Informal Document 7 EGTEI Guidance-Document On Stationary Sources Tracked Changes Compared With WGSR Version

Convention on Long-Range Transboundary Air Pollution
th
50 Working Group on Strategies and Review – 10 to 14 September 2012
Prepared by EGTEI
Guidance document on control techniques for emissions of

sulphur, NOx, VOCs, dust (including PM10, PM2.5 and black
carbon) from stationary sources
Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (Including PM 10, PM2.5
and black carbon) from stationary sources
5 July24 September 2012 Page 2

List of abbreviations and acronyms
AEL Associated Emission Levels

ACI Activated carbon injection
3 3
Am Actual m
AS Air staging
ASK Annular shaft kiln
BAT Best Available Techniques
BBF Biased Burner Firing
BC Black Carbon
BF Blast furnace
BOF Basic oxygen furnace
BOOS Burners Out of Service
Bra Brown Carbon Mis en forme : Anglais (Royaume-Uni)
BREF Best available technique reference document
BTEX Benzene, toluene, ethylbenzene, and xylenes
°C Celsius degree
C eq Carbon equivalent
CaO Calcium oxide
CaCO3 Calcium carbonate
Ca(OH)2 Calcium hydroxide
C3+ Carbon ion
CCGT Combined Cycle Gas Turbines
CCS Carbon capture and storage
CDQ Coke dry quenching
CFBC Circulating fluidised-bed combustion
CFA Circulating fluidised-bed absorber
CHP Combined Heat and Power
COG Coke Oven Gas
COHPAC Compact Hybrid Particulate Collector
CONCAWE European Oil Company Organisation for Environment, Health and Safety
Co Cobalt
CO Carbon Monoxide
CO2 Carbon Dioxide
COC Condensable organic compounds
CPIV Comité Permanent des Industries du Verre de la CEE
Cr Chromium Mis en forme : Anglais (États Unis)
Cu Copper
DF Dual Fuel
DLN Dry low NOx
DPF Diesel Particulate Filters
DRI Direct Reduced Iron
€/kW Euro per Kilo watt
€/kWh Euro per Kilo Watt hour
€/ton Euro per ton
EAF Electric arc furnace Mis en forme : Anglais (États Unis)
UNECE United Nations Economic Commission for Europe
EED Energy efficient design

EGR Exhaust gas recirculation

ELV Emission Limit Value
EMEP European Monitoring and Evaluation Programme under the Convention on
Long-Range Transboundary Air Pollution (LRTAP)
ESP Electrostatic precipitator
FBC Fluidized bed combustion
FCC Fluid Catalytic Cracking
Fe Iron
FF Fabric filter
FGD Flue gas desulphurisation
FGR Flue Gas Recirculation Mis en forme : Anglais (États Unis)
FR Fuel re-burning
FS Fuel staging
GD Gas Diesel Mis en forme : Anglais (États Unis)
GHG Greenhouse Gases
GJ Giga Joule
GSA Gas suspension absorber Mis en forme : Anglais (États Unis)
HCl Hydrochloric Acid
H2S Hydrogen sulphide
HEPA High efficiency particulate air filter
HF Hydrogen fluoride
HFO Heavy Fuel Oil
H2 Hydrogen
Hg Mercury
H2SO4 Sulphuric acid
IFC International Finance Corporation
IGCC Integrated gasification combined-cycle
IPPC Integrated Pollution Prevention and Control
IPTS Institute for Prospective Technological Studies
K Kelvin
kPa Kilo Pascal
kV Kilo Volt
kWel Kilowatt electric
LDAR Leak detection and repair programme
LEA Low excess air combustion
LFO Light Fuel Oil
LICADO Liquid Carbon Dioxide
LIMB Limestone Injection Multistage Burner
LNB Low NOx Burners
LPG Liquefied petroleum gas
LRK Long rotary kiln
mg/l Milligramme per litre
3
mg/m Milligramme per cubic metre
3
mg/Nm Milligramme per normal cubic metre
mg/t Milligramme per ton Mis en forme : Français (France)
MCR Maximum Continuous Rating
MFSK Mixed feed shat kiln
Mg Megagramme, metric ton

Ni Nickel
Mn Manganese
Mo Molybdenum
MSW Municipal solid waste
MW Mega Watt
MWth Mega Watt Thermal
MWe Mega Watt Electric
3
µg/Nm Microgramme per normal cubic metre
µm Micrometer
N2 Nitrogen
NaHCO3 Sodium bicarbonate
NOx Nitrogen oxide
NFM Non ferrous metal
NMVOC Non-methane volatile organic compounds
O2 Oxygen
OC Organic Carbon
OFA Over Fire Air
OSK Other shaft kiln
PAH Polycyclic aromatic hydrocarbon
PCDD/F polychlorinated dibenzodioxin/furan
PCDF Polychlorinated dibenzofurans
PFBC Pressurized fluidized bed combustion
PFRK Parallel flow regenerative kiln
PM Particulate matter
PM2,5 Particulate matter (2,5 micrometer)
PM10 Particulate matter (10 micrometer)
ppm Parts per million
PRK Pre-heater rotary kiln
RAINS Regional Air Pollution Information and Simulation
RAP Reduced air preheat
SCR Selective Catalytic Reduction
SG Spark Gas (engines)
SNCR Selective non-catalytic reduction
SRA Sulphur Reducing Additives
SRU Sulphur Recovery Unit
SO2 Sulphur dioxide
TA-LUFT Technische Anleitung zur Reinhaltung der Luft (Technical Instructions on Air
Quality Control)
TCC Thermal catalytic cracking
TOC Total organic carbon
TSP Total Suspended Particles
UNECE United Nations Economic Commission for Europe
UNEP United Nations Environment Programme
VOC Volatile Organic Compound
WMO World Meteorological Organisation

Voluntary left blank

CONTENT
1 Introduction 117
2 Common general issues for the pollutants considered 1713

2.1 Monitoring and reporting 1713
2.2 Energy management, energy efficiency, energy mix 1713
3 General issues for sulphur 1915

3.1 General issues 1915
3.2 Sulphur content of fuels 1915
3.3 Fuel switching 1915
3.4 Fuel cleaning 1915
3.5 Combustion Technologies 2016
3.6 Secondary measures - Flue gas desulphurisation processes 2016
3.7 Costs of reduction techniques of SO2 2218
3.8 By products and side effects 2218
3.9 References used in chapter 3 2319
4 General issues for NOx 2420

4.4 Primary measures 2420
4.5 Secondary measures 2622
4.6 Costs of NOx emission reduction techniques 2824
4.7 Side effects 2925
5 General issues for VOCs 3127

5.2 Knowledge of emissions and solvent management plan 3228
5.3 General approaches to reduce VOCs emissions 3329
5.3.1 Primary measures 3430
5.3.2 Secondary measures 3430
5.4 Costs 3733
6 General issues for dust (including PM10, PM2,5 and BC). 3935

6.4 Primary measures 4541

6.5 Secondary measures 4541
6.6 Costs of dust emission reduction techniques 5046
7 Available techniques for different activities 5349

7.1 Combustion installations <1MW with domestic combustion installation included 51
7.2 Combustion installations from 1 to 50 MW 61
7.3 Combustion installations > 50 MW 65
7.4 Mineral oil and gas refineries for SO 2, NOx and dust emissions 79
7.5 Mineral oil and gas refineries for VOC emissions 87
7.6 Coke Oven furnaces 93
7.7 Iron and steel production 97
7.8 Ferrous metals processing including iron foundries 105
7.9 Non ferrous metal processing industry 113
7.10 Cement production 123
7.11 Lime production 129
7.12 Glass production 135
7.13 Man-made fibre production 147
7.14 Ceramics manufacturing industry 153
7.15 Pulp production 161
7.16 Nitric acid production 169
7.17 Sulphuric acid production 171
7.18 Municipal, medical and hazardous waste incineration) 177
7.19 Industrial wood processing 183
7.20 Petrol distribution – from the Mineral oil refinery dispatch stations (petrol) to
service-stations including transport and depots (petrol) 187
7.21 Storage and handling of organic compounds (except petrol covered by chapters
7.5 and 7.21) 193
7.22 Production of organic chemicals (excluding fine organic chemical production) 197
7.23 Production of organic fine chemicals 201
7.24 Adhesive coating (including footwear manufacture) General coating, shoe
industry, lamination 205
7.25 Coating processes 1: Manufacture of cars, Manufacture of truck cabins, trucks,
Manufacture of buses and trailers 207
7.26 Coating processes 2: Winding wire coating 211
7.27 Coating processes 3: Coil coating 213
7.28 Other coating processes 4: Other industrial coating 215
7.29 Solvent content in products 1: Domestic and architectural paints 219

7.30 Manufacturing of coatings, varnishes, inks and adhesives 221

7.31 Printing processes 223
7.32 Rubber processing 227
7.33 Dry cleaning 229
7.34 Metal degreasing 233
7.35 Vegetable oil and animal fat extraction and vegetable oil refining 239
7.36 Vehicle refinishing 243
7.37 Wood impregnation 245
7.38 Solvent content in products 2: Domestic uses of solvent (other than paints) 247
7.39 Beer production 249
7.40 Titanium dioxide production 253
7.41 New stationary engines 257

Acronyms used
The following acronyms are used throughout the guidance document:
BAT Best available technique Mis en forme : Taquets de
tabulation : Pas à 1.5 cm + 4 cm
BC Black carbon
Dust Used in the same way as TSP
ELV Emission limit value
FF Fabric Filter
3
Nm Cubic meter at standard conditions (101,325 kPa and 273.15 K)
SNCR Selective Non-Catalytic Reduction
VOCs In the context of the Gothenburg Protocol, all organic compounds of an Mis en forme : Retrait : Gauche : 0
anthropogenic nature, other than methane, that are capable of producing photochemi cal oxidant by cm, Espace Avant : 3 pt, Taquets de
tabulation : Pas à 1.5 cm + 14.75 cm
reaction with nitrogen oxides in the presence of sunlight

1 Introduction
The aim of this document is to provide the Parties to the Convention on Long-Range Transboundary
Air Pollution with guidance on identifying best abatement options, with particular reference to best
available techniques (BAT) to enable them to meet the obligations of the Protocol to abate
Acidification, Eutrophication, Ground Level Ozone and dust (including PM10, PM2,5 and BC).
This guidance document addresseslists control options for the following pollutants:
the control options for NOx emissions defined as the sum of nitric oxide (NO) and nitrogen
dioxide (NO2) expressed as nitrogen dioxide (NO2),
the control options of sulphur emissions considered including as all sulphur compounds
expressed as sulphur dioxide (SO2).
the control options of VOC emissions considered defined as all organic compounds of an
anthropogenic nature, other than methane, that are capable of producing photochemical oxidant
by reaction with nitrogen oxides in the presence of sunlight.
the control options of particulate matter (PM) emissions consisting of a mixture of particles
suspended in the air including dust or Total Suspended Particulate Matter (TSP) , (including
PM10, PM2.5 and black carbon (BC)) whose definitions are as follows:
- PM2.5 : particles with an aerodynamic diameter equal to or less than 2.5 microns (µm);
- PM10: particles with an aerodynamic diameter equal to or less than 10 microns (µm);
- Dustdust or TSP: for the purpose of the guidance document “dust” and “total suspended
particulate matter” (TSP) means the mass of particles, of any shape, structure or density,
dispersed in the gas phase at the sampling point conditions which may be collected by filtration
under specified conditions after representative sampling of the gas to be analyzed, and which
remain upstream of the filter and on the filter after drying under specified conditions .
- black carbon (BC): carbonaceous particulate matter that absorbs light.
In the context of this guidance document, dust and TSP have the same meaning. As can be seen from
chapter 6, abatement techniques for dust in general also provide high removal efficiency for PM 10, and
in some cases, PM2.5. However, some measures will reduce coarse particles much more efficiently
than finer particles such as PM2.5; therefore, specific measures targeting PM2.5 and BC are necessary.
As monitoring data for specific fractions of particulate matter such as PM 2.5 and PM10 are in general
not presently available, emission levels are defined for dust.
The expression “Best available techniques” means the most effective and advanced stage in the
development of activities and their methods of operation which indicate the practical suitability of
particular techniques for providing the basis for emission limit values and other permit conditions
designed to prevent and, where that is not practicable, to reduce emissions and the impact on the
environment as a whole:
(a) “techniques” includes both the technology used and the way in which the installation is designed,
built, maintained, operated and decommissioned,
(b) “available” techniques means those developed on a scale which allows implementation in the
relevant industrial sector, under economically and technically viable conditions, taking into
consideration the costs and advantages, whether or not the techniques are used or produced inside
the Member State in question, as long as they are reasonably accessible to the operator,
(c) “best” means most effective in achieving a high general level of protection of the environment as a
whole.
Criteria for determining BAT are as follows:
1. the use of low-waste technology;
2. the use of less hazardous substances;
3. the furthering of recovery and recycling of substances generated and used in the process and
of waste, where appropriate;

4. comparable processes, facilities or methods of operation which have been tried with success
on an industrial scale;
5. technological advances and changes in scientific knowledge and understanding;
6. the nature, effects and volume of the emissions concerned;
7. the commissioning dates for new or existing installations;
8. the length of time needed to introduce the best available technique;
9. the consumption and nature of raw materials (including water) used in the process and
energy efficiency;
10. the need to prevent or reduce to a minimum the overall impact of the emissions on
the environment and the risks to it;
11. the need to prevent accidents and to minimize the consequences for the environment;
12. information published by national and international organisations.
This guidance document presents BAT Associated Emission Levels (AELs) which can be described as
follows:
BAT AELs are levels that an operator can expect to achieve when using the BAT, and are
appropriate reference points to assist in the determination of permit conditions,
BAT AELs represent average emission levels achievable during a substantial period of time in
normal operating and/or design conditions (well-proven technology),
BAT AELs are neither emission nor consumption limit values.
BAT AELs are based on normal operating conditions and may vary with changing input materials or
for varying outputs.
The BATAELs are based on a range of averaging periods and represent a typical load situation.
Therefore, when taking account of BATAELs in the context of ELV setting, proper regard must always
be given to the reference period to which the described BATAEL pertains. For peak load, start up and
shut down periods, as well as for operational problems of the flue gas cleaning systems, short-term
peak values, which could be higher, have to be regarded.
Where a level is described as "achievable" using a particular technique or combination of techniques,
this should be understood to mean that the level may be expected to be achieved over a substantial
period of time in a well maintained and operated installation or process using those techniques.
Unless otherwise indicated, the reduction measures listed are considered, on the basis of operational
experience of several years in most cases, to be the most well-established and economically feasible
3
best available techniques. BAT Associated Emission Levels are generally expressed in mg/m (dry
gas, 273.15K and 101.325 kPa except is stipulated different) as daily average. For organic solvent
uses they can be expressed in % of solvents used (solvents purchased + solvents internally recycled).
The continuously expanding experience with low-emission measures and technologies at new plants
as well as with the retrofitting of existing plants will necessitate regular review of this document.
Although this guidance document lists a number of measures and technologies, spanning a wide
range of costs and efficiencies, it cannot be considered as an exhaustive statement of control options.
Moreover, the choice of control measures and technologies for any particular case will depend on a
number of factors, including current legislation and regulatory provisions and, in particular, control
technology requirements, primary energy patterns, industrial infrastructure, economic circumstances
and specific in-plant conditions.
This guidance document provides options and techniques, along with their performance assessment
for emission prevention and reduction of Sulphur, NOx, VOCs, dust (including PM10, PM2,5 and BC).
However, the reduction of a given pollutant cannot be considered without taking into account the risk
of generating other pollutants and/or increasing energy consumption. It is worthwhile to consider them
together along with such other pollutant-specific control options in order to maximize the abatement

effect and minimize the impact on the environment. Respective co-benefit/trade-off between different
pollutants have to be carefully accounted for. This is particularly important for multi-pollutant/multi-
effect approach where positive/negative effects on the reduction of Greenhouse Gases (GHGs) are
possible (For example, measures that improve the efficiency of combustion will generally reduce both
BC and CO2)..
This guidance document provides options and techniques, along with their performance assessment
for emission prevention and reduction of Sulphur, NO x, VOCs, dust (including PM10, PM2,5 and BC).
Performance and costs are documented in a series of documents elaborated by EGTEI, in the draft
background document submitted to the UNECE Task Force on Heavy Metals (TFHM) of 2006, the EU
Commission with the different Best Available Reference documents (BREF) and other recent
publications, US EPA reports and a series of documents acknowledged nationally or internationally.
In this document, both primary and secondary measures are considered. Primary reduction measures
aim at reducing pollutant emissions at their sources of formation. Secondary measures aim at treating
waste gases containing already formed pollutants (add-on or end of pipe technologies).
This guidance document covers the stationary sources emitting Sulphur, NOx, VOCs, dust (including
PM10, PM2,5 and BC) listed in table 1. Mobile sources (road traffic, non road traffic and off road
machineries) are covered by the guidance document on mobile sources. Some stationary sources are
not covered by this guidance document but may be significant sources of BC for some countries, such
as agricultural burning, open biomass burning, flares in gas and petroleum extraction, existing
stationary diesel engines.

Table 1: stationary sources for emissions of sulphur, NOx, VOCs, dust (including PM10, PM2,5
and BC) covered by this guidance document
SO2 NOx Dust BC VOCs
7-1 Combustion installation < 1MW with domestic combustion

Y Y Y Y Y
installation included
7-2 Combustion installations from 1 to 50 MW
Y Y Y Y Y
(a) Boilers (b) Gas turbines
7-3 Combustion installations > 50 MW
Y Y Y Y Y
(a) Boilers (b) Gas turbines
7-4 Mineral oil and gas refineries
Combustion and furnaces for emissions of SO2, NOx and dust Y Y Y Y
(including PM10, PM2,5 and BC) including processes heaters,
FCC, TCC and flares)
7-5 Mineral oil and gas refineries
Y
Processes and sources of NMVOC
7-6 Coke oven furnaces Y Y Y Y Y
7-7 Iron and steel production (iron and steel making in integrated
steelworks (sinter plants, pelletization plants, blast furnaces and
Y Y Y Y Y
basic oxygen furnaces including continuous and ingot casting)
and electric arc furnace steelmaking)
7-8 Ferrous metals processing
iron foundries with a capacity exceeding 20 tonnes/day, as well
as installations for “hot and cold forming”, including hot rolling, Y Y Y Y Y
cold rolling, wire drawing, installations for “continuous coating”,
including hot dip coating and coating of wire, and installations for
“batch galvanizing”
7-9 Non ferrous metal processing industry (primary and secondary
Al production, primary and secondary Pb production, primary
Y Y Y Y
and secondary Zn production and primary and secondary Cu
production)
7-10 Cement production Y Y Y Y
7-11 Lime production Y Y Y Y
7-12 Glass production Y Y Y Y
7-13 Man-made fibre production Y Y Y Y Y
7-14 Ceramics manufacturing industry Y Y Y Y
7-15 Paper pulp production Y Y Y Y
7-16 Nitric acid production Y Y Y
7-17 Sulphuric acid production Y Y Y
7-18 Waste incineration (domestic and industrial waste, waste water
Y Y Y Y
treatment sludge incineration)
7-19 Industrial wood processing Y
7-20 Petrol distribution – from the mineral oil refinery dispatch
stations (petrol) to service stations including transport and Y
depots (petrol)
7-21 Storage and handling of organic compounds (except petrol
Y
covered by chapters 7.5 and 7.21)

Table 1: stationary sources for emissions of sulphur, NOx, VOCs, dust (including PM10, PM2,5
and BC) covered by this guidance document
SO2 NOx Dust BC VOCs
7-22 Production of organic chemicals (excluding fine organic

Y
chemical production)
7-23 Production of organic fine chemicals Y
7-24 Adhesive coating (including footwear manufacture)
Y
General coating, shoe industry, lamination
7-25 Coating processes 1
Manufacture of cars
Y
Manufacture of truck cabins, trucks
Manufacture of buses and trailers
Y
Winding wire coating
Y
Coil coating
7-28 Other coating processes 4
Y
Other industrial coating
7-29 Solvent content in products 1: Domestic and architectural paints Y
7-30 Manufacturing of coatings, varnishes, inks and adhesives Y
7-31 Printing processes (Packaging printing, cold set offset
Y
heat set offset, publication sector, screen printing)
7-32 Rubber processing Y
7-33 Dry cleaning Y
7-34 Metal degreasing Y
7-35 Vegetable oil and animal fat extraction and vegetable oil refining Y
7-36 Vehicle refinishing Y
7-37 Wood impregnation Y
7-38 Solvent content in products 2:
Y
Domestic uses of solvent (other than paints)
7-39 Beer production Y
7-40 Titanium dioxide production Y Y Y
7-41 New stationary gas and diesel engines Y Y Y

Acronyms used
The following acronyms are used throughout the guidance document:
BAT Best available technique Mis en forme : Taquets de
BC Black carbon
Dust Used in the same way as TSP
ELV Emission limit value
FF Fabric Filter
3
Nm Cubic meter at standard conditions (101,325 kPa and 273.15 K)
SNCR Selective Non-Catalytic Reduction
VOCs In the context of the Gothenburg Protocol, all organic compounds of an anthropogenic Mis en forme : Retrait : Gauche : 0
nature, other than methane, that are capable of producing photochemical oxidant by reaction with cm, Première ligne : 0 cm, Taquets de
nitrogen oxides in the presence of sunlight

2 Common general issues for all the pollutants considered in this

report
2.1 Monitoring and reporting
Several monitoring systems, using both continuous and discontinuous measurement methods, are
available. However, quality requirements vary. Measurements are to be carried out by qualified
institutes using measuring and monitoring systems that meet international standards. To this end, a
certification system can provide the best assurance.
In the framework of modern automated monitoring systems and process control equipment, reporting
does not create a problem. The collection of data for further use is a state-of-the-art technique.
However, data to be reported to competent authorities differ from case to case. To obtain better
comparability, data sets and prescribing regulations should be harmonized. Harmonization is also
desirable for quality assurance of measuring and monitoring systems. This should be taken into
account when comparing data.
To prevent discrepancies and inconsistencies, key issues and parameters, including the following,
must be well defined:
3
(a) definition of standards expressed as ppmv, mg/Nm , g/GJ, kg/h or kg/Mg of product. Most of
these units need to be calculated and need specification in terms of gas temperature,
humidity, pressure, oxygen content or heat input value;
(b) definition of the period over which standards are to be averaged, expressed as hours, months
or a year, and of the measuring method;
(c) definition of failure times and corresponding emergency regulations regarding bypass of
monitoring systems or shutdown of the installation;
(d) definition of methods for backfilling data missed or lost as a result of equipment failure;
(e) definition of the parameter set to be measured. Depending on the type of industrial process,
the necessary information may differ. This also involves the location of the measurement point
within the system.
Quality control of measurements has to be ensured.
2.2 Energy management, energy efficiency, energy mix

The major part of the sulphur, NOx, and dust (including PM10, PM2,5 and BC) emissions from
stationary installations result from fuel combustion to produce heat and power. Reducing fuel
combustion via an efficient and rational use of energy (energy management) may be therefore an
efficient measure to reduce these air emissions but also the emissions of other pollutants and of
greenhouse gases. Energy management may also contribute to increasing security of energy supply
and a reduced consumption of natural resources. On the level of stationary installations but also on
the level of production sites energy management means to increase overall energy efficiency by a
number of different measures which can be realized alone or at best in combination like:
implementation of an energy efficiency management system (ENEMS)
establishment of a systems view for energy efficiency
benchmarking
energy efficient design (EED)
process integration
expertise and know-how gains on energy efficiency
effective control, maintenance and monitoring of installations
BAT is the optimisation of the combustion and steam systems but also the systems for compressed
air, pumping, heating, cooling, ventilation, lighting, and other physical and chemical processes using a

large number of techniques. Of particular importance are also heat recovery and cogeneration if
reasonable [from [1]].
Besides energy management which focuses more on the demand side, the supply side for energy has
also a large impact on air emissions. Besides fuel switch where one (fossil) fuel is replaced by another
also a change in the energy mix should be considered taking into account country specific conditions
such as infrastructure, energy policy and availability of resources of fossil fuels and renewable energy
like wind power, solar energy, geothermal energy or biomass. Burning more biomass, especially in
stoves, may, however, also lead to increasing air emissions.
Reference used for this chapter:

[1] European Commission (2008): Reference Document on Best Available Techniques, Energy
Efficiency]

3 General issues for sulphur

3.1 General issues
In order to reduce SOx emissions from combustion processes or other sources, different types of
measures are applied. The main applied techniques: energy efficiency improvement, fuel switching,
fuel cleaning, primary and secondary measures are presented in this chapter.
SO2 is a major contributor to acidification, via the formation in the atmosphere, of sulphate and
sulphuric acid. SO2 residence time in atmosphere depends on meteorological conditions. The average
residence time is about 3 to 5 days, hence SO 2 can be transported over hundred kilometres.
To achieve the most efficient SOx emission reduction, beyond energy management measures, a
combination of measures should be considered.
3.2 Sulphur content of fuels
Sulphur present in fuels reacts with oxygen contained in combustion air to form SO2. Therefore SO2
emissions arising from combustion are directly related to the sulphur content of fuels used. SO 3 is
produced by oxidation of SO2, during combustion.
Sulphur content of solid fossil fuels ranges from 0.5 % to more than 5 %. Solid fossil fuels are the
largest sources of SO2 [1]. Sulphur content of natural gas is very low as well as sulphur content of
wood. Sulphur content of liquid fossil fuels ranges from 0.001 % to more than 5 %. The availability of
low sulphur content liquid fossil fuels requires the removal of sulphur at the refinery and the adoption
of specific processes.
During the last decade, national and European legislation have toughened the limits required for the
sulphur content of petroleum products. The table 2 presents the typical limit values applied for liquid
fuels in the EU [2].
Table 2: typical limit values applied for liquid fuels in the EU
Fuel Current sulphur content (% weight) EU directive

Residual oil < 1 % or 10000 ppm 1999/32/EC
Gas-oil < 0.1 % or 1000 ppm 1999/32/EC
3.3 Fuel switching

Fuel switching (e.g. from high- to low-sulphur coals and/or liquid fuels, or from coal or liquid fuel to
gas) leads to lower sulphur emissions, but there may be certain restrictions, such as the availability of
low-sulphur fuels and the adaptability of existing combustion systems to different fuels. In many EU
countries, some coal or oil combustion plant is being replaced by gas-fired combustion plant. Dual-fuel
plant may facilitate fuel switching. Fuel switching can also have beneficial effects on nitrogen dioxide
or particulate matter emission levels.
3.4 Fuel cleaning

Cleaning of natural gas is state-of-the-art technology and widely applied for operational reasons.
Cleaning of process gas (acid refinery gas, coke oven gas, biogas, etc.) is also state-of-the-art
technology. Desulphurization of liquid fuels (light and medium fractions) is state -of-the-art technology.
Desulphurization of heavy fractions is technically feasible; nevertheless, the crude o il properties
should be kept in mind. Desulphurization of atmospheric residue (bottom products from atmospheric
crude distillation units) for the production of low-sulphur fuel oil is not, however, commonly practised;
processing low-sulphur crude is usually preferable. Hydro-cracking and full conversion technology has
matured and combine high sulphur retention with improved yield of light products. The number of full
conversion refineries is constantly rising. Such refineries typically recover 80 to 90% of the sulphur
intake and convert all residues into light products or other marketable products. This type of refinery

consumes more energy and requires higher investments. Sulphur content of refinery products needs
to correspond to the restricted value ordered by the EU and provided in table 2. Current technologies
to clean hard coal can remove approximately 50% of the inorganic sulphur (depending on coal
properties) but none of the organic sulphur. More effective technologies are being developed.
However, they require higher specific investments. Thus the efficiency of sulphur removal by coal
cleaning is limited compared to flue gas desulphurisation. There may be a country-specific
optimisation potential for the best combination of fuel cleaning and flue gas cleaning.
3.5 Combustion Technologies

Advanced combustion technologies may improve thermal efficiency and reduce sulphur emissions.
These technologies include fluidized-bed combustion (FBC), integrated gasification combined-cycle
(IGCC); and combined-cycle gas turbines (CCGT). Stationary combustion turbines can be integrated
into combustion systems in existing conventional power plant. This can increase overall efficiency by 5
to 7%, leading, for example, to a significant reduction in SO 2 emissions. However, major alterations to
the existing furnace system become necessary. Reciprocating engines can also increase the electrical
efficiency by taking advantage of the sensible heat of the exhaust gases generated by e.g. use of a
feed-water combined cycle.
In FBC, the combustion takes place through a particulate bed, which can be fixed (FFBC), pressurized
(PFBC), circulating (CFBC) or bubbling (BFBC). Fluidized-bed combustion is a combustion technology
for burning hard coal and brown coal, but it can also burn other solid fuels, such as petroleum coke,
and low-grade fuels, such as waste, peat and wood. Emissions can be further reduced by integrated
combustion control in the system due to the addition of lime/limestone to the bed material. The use
and/or disposal of by-products from this process may cause problems and further development is
required.
The IGCC process includes coal gasification and combined-cycle power generation in a gas and
steam turbine. The gasified coal is burnt in the combustion chamber of the gas turbine. Sulphur
emission control is achieved by using state-of-the-art technology for raw gas cleaning facilities
upstream of the gas turbine. The technology also exists for heavy oil residues and bitumen emulsions.
Combustion modifications comparable to the measures used for NOx emission control do not exist, as
during combustion the organically and/or inorganically bound sulphur is almost completely oxidized. A
certain percentage, depending on the fuel properties and combustion technology, is retaine d in the
ash. The amount of sulphur retained in ash, can be influenced by added sorbents (e.g. lime/limestone)
and combustion conditions (e.g. temperature). In this guidance document dry additive processes for
conventional boilers are considered as process modifications due to the injection of an agent into the
combustion unit. However, experience has shown that, when applying these processes, thermal
capacity is lowered, and the Ca/S ratio is relatively high and sulphur removal low. In recent years, the
performance of these processes has nevertheless been optimized to the point that SO 2 removal
efficiency reached 50 - 80%. Problems with the further use of the by-product have to be considered.
3.6 Secondary measures - Flue gas desulphurisation processes
These processes aim at removing already formed sulphur oxides, and are considered as secondary
measures. Sulphur removal using wet, dry or semi-dry processes are used to treat the flue gases.
Sulphur can also be removed using the recovery of sulphur dioxide from the flue gases. It is then
either extracted (regenerative process) or converted into sulphuric acid (sulphuric acid plant). Flue gas
scrubbing using water or seawater is another available technology to reduce SO 2 emissions.
In wet scrubbing technologies, the flue gas is first dedusted then cleaned by an atomized solution of
alkaline compounds. SO2 reacts with these alkaline compounds to form by products, whose chemical
nature depends on the alkaline compound used. In the case of use CaCO3 or CaO, by products may
be upgraded as gypsum if some technical conditions are achieved. By products can also be upgraded
using other scrubbing agent. With wet FGD, excellent efficiencies can be achieved ranging from 92 to
98% with a near-stoichiometry Ca/S ratio. This process is mainly used for reducing SO 2 emissions
from coal power plants.

In the dry process, a calcium or sodium based sorbent is injected in solid form into the flue gases
before a fabric filter or an ESP. Hydrated lime (Ca(OH) 2) or sodium bicarbonate (NaHCO3) are the
most frequently used sorbents. Sorbents need to be very reactive and are activated for this purpose
(finely ground CA(OH)2 with high activity as example). They react with SO2 to form calcium or sodium Mis en forme : Indice
sulphites and sulphates, which need then to be filtered in order to reduce dust emissions. The dry duct
injection process efficiency is lower than with wet FGD (about 50 % ) and depends on several
parameters such as temperature, SO2 content of the flue gas, Ca/S ratio and residence time.
Furnace sorbent injection is a direct injection of a dry sorbent in the gas stream of the boiler furnace.
Pulverised limestone is used (CaCO3). Calcium sulphites and sulphates formed need to be captured
by FF or ESP. Efficiencies from 70 to 80 % may be obtained according to the arrangement used [4].
The semi-dry process or spray dry scrubbing is similar to the dry process and also produces a solid
residue. It uses moisturised lime or limestone containing about 10% of water to enhance the contact
and the reactions. The removal SO2 efficiency ranges from 85 to 92% with a ratio Ca/S from 1.3 to 2
[4].
In regenerative processes, a regenerating agent is used to recover SO 2. The sodium sulphite

bisulphite process is one of these regenerative processes. Sodium sulphite (Na2SO3) reacts with SO2
to form sodium bisulphite (NaHSO3), which is then evaporated to crystallise sodium sulphite and
recover SO2. A recovery rate of more than 95% can be achieved. This type of process is commonly
used in titanium dioxide production plants. This process requires qualified operating staff.
In sulphuric acid production, SO2 is first oxidised to SO3 which is absorbed to form sulphuric acid. The
sulphuric acid production process can include a single absorption stage or a double one depending on
the conversion rate to be achieved. Double absorption sulphuric acid plant is more effective.
Flue gas desulphurisation is a high capital cost process best suited to high load factor plant.
The following table presents general results for several flue gas desulphurisation processes.
Table 3: general description and performance for selected flue gas desulphurisation processes
[3]
Acid sulphuric
Regenerative
Wet scrubbing Dry scrubbing plant (double
process
absorption)
Desulphurisation
Desulphurisation rate of 50 % to 80%
rate of 95 % to depending on the
Recovery rate of Conversion rate of
Efficiency 98%) for a Ca/S Ca/S ratio and
95-98 % > 99%
ratio from 1.02 to systems (dry duct
1.1 injection or furnace
injection)
Gypsum can be
obtained under
certain conditions Calcium sulphite
By-product and can be suitable and sulphate not
for use in recoverable
plasterboard
production
Inlet dust
concentration
Not cost effective, 3
< 30 mg/Nm
Possible problem of large amount of
Limits Inlet O2
scaling waste to be treated
accordingly concentrations to be
5 times higher than
SO2 concentrations.

To achieve the most efficient process for sulphur emission reductions beyond the energy management
measures listed above, a combination of technological options identified in the paragraphs above
should be considered. In some cases, options for reducing sulphur emissions may also reduce
emissions of NOx and other pollutants.
3.7 Costs of reduction techniques of SO2
Costs are an important issue when selecting SO2 emission reduction techniques. The following
expenses may be relevant:
imputed depreciation allowance and imputed interest,
labour costs,
expenses for auxiliary and operating materials,
energy costs,
maintenance and repair costs, expenditure on monitoring, expenses for external services,
taxes, environmental levies (e.g. charges for waste water), fees, public charges.
Costs increase in general less than the capacity of the reduction technique so that larger units are
often more cost-effective or unit with higher flue gas sulphur content. Dry additive processes are less
cost effective for high sulphur content fuels compared to wet scrubbing processes.
Costs of SO2 abatement techniques are developed in chapter 7.
3.8 By products and side effects
Side effects of emission abatement options/techniques can be positive or negative and should be
accounted for.
Options that lead to usable by-products should be selected, as should options that lead to increased
thermal efficiency and reduced waste whenever possible. Although most by-products such as gypsum,
ammonia salts, sulphuric acid or sulphur, are usable or recyclable products, factors such as market
conditions and quality standards need to be taken into account.
Side effects can generally be limited by properly designing and operating the facilities. Side effects
include
impacts on energy consumption and hence greenhouse gas emissions,
impacts on other air pollutants,
impacts on the use of natural resources such as limestone,
cross-media effects, e.g. on waste or water.
More particularly, the following table presents positive and negative side effects for selected flue gas
desulphurisation processes.
Table 4: positive and negative side effects for selected flue gas desulphurisation processes
Abatement technique Positive side effect Negative side effect

Calcium sulphite and sulphate not
Dry scrubbers or additive recoverable
Reduction of dust and heavy metals
injection process
Large amount of waste produced
Water consumption
Reduction of dust and heavy metals
Energy consumption
Wet scrubbers Possible upgrade of by-products to
Limestone consumption
gypsum
Waste generation

3.9 References used in chapter 3

[1] DGEMP, direction générale de l’énergie et des matières premières,
http://www.industrie.gouv.fr/energie/,
th
[2] European directive 1999/32/ EC, UEOJ 26 April 1999.
[3] Techniques de désulphurisation des procédés industriels, ADEME, 1999.
[4] LCP BREF (2006): Reference Document on Best Available Techniques for Large Combustion
Plants. – European Commission, 618 pp.

4 General issues for NOx

4.1 General issues
The generic term NOx refers to the sum of nitrogen oxide (NO) and nitrogen dioxide (NO 2), expressed
as NO2. Nitrous oxide (N 2O), a greenhouse gas, is not covered in NOx. The main source for NOx is
combustion where primarily NO is formed [1]. NO is then rapidly converted to NO2.
NOx emissions contribute to acidification via formation of nitrous acid (HNO 2) and nitric acid (HNO3),
to eutrophication, to tropospheric ozone formation and (in particular NO 2) to irritation and damage to
respiratory organs. Furthermore, NOx may react with ammonia to form secondary fine particles with
negative health effects.
In combustion, three main types of NOx formation are distinguished:
thermal NOx: molecular nitrogen (N2) from air and molecular oxygen (O2) dissociate at high
temperature and react to form NOx. The reaction is reversible and usually becomes significant
at temperatures above around 1300 °C [1]. NOx formation increases with temperature and
residence time.
fuel NOx: in fuel NOx, the nitrogen source for NOx formation is the fuel itself. Two path ways
may be distinguished: i) during initial combustion, volatiles including oxidized nitrogen are
released and ii) during later stages when the char is oxidized and the nitrogen contained in the
char is oxidized to NOx. Fuel NOx formation is significant at temperatures above about 800°C.
The amount of fuel NOx depends on the N content of fuels and on combustion conditions.
prompt NOx: fuel radicals react with molecular nitrogen (N2) from the air to form NOx.
Compared to thermal and fuel NOx, prompt NOx is of lesser importance for the sources
considered here.
In order to reduce NOx formation and NOx emissions from combustion processes different types of
measures like energy efficiency improvements (cf. Chapter 2), fuel switch as well as primary and
secondary measures are applied. To achieve the most efficient NOx reduction, beyond energy
management measures, a combination of measures should be considered. To identify the best
combination of measures, a site-specific evaluation is needed.
4.2 Fuel switching

Switching to low NOx producing fuels is one option to reduce NOx emissions but is governed by
country specific conditions such as infrastructure and energy policy. Fuels with high nitrogen content
like heavy fuel oil and coal may lead to high fuel NOx formation and hydrogen rich fuels like natural
gas as a result of high combustion temperatures to high thermal NOx formation. The choice of the fuel
may also have effects on other emissions like sulphur, particulate matter and greenhouse gas
emissions as well as on applicability and need of abatement measures.
4.3 Fuel cleaning

Fuel cleaning to remove nitrogen is not a commercial option. Hydroprocessing in refineries, however,
also reduces the nitrogen content of end products.
4.4 Primary measures

Primary measures reduce NOx generation at the source by a number of different principles o r
methods or a combination of them [1]:
reducing peak temperature,
reducing residence time at peak temperature,
chemical reduction of NOx during combustion process,
reducing nitrogen in the combustion process.

In the following paragraphs, an overview on available primary measures is given. Their applicability
depends on the industrial sector and the production process.
Reducing peak temperature: As thermal NOx formation depends largely on the combustion
temperature, a reduction in temperature is one option to reduce NOx formation. Reducing peak
temperature can be achieved by the following methods i) diluting the heat produced during the
combustion process, ii) cooling down, and iii) reducing the oxygen available for combustion [1] but
also by applying other combustion techniques like fluidized bed combustion (FBC) which operates at
lower temperatures and includes an inherent air-staging. Main methods for reducing peak temperature
are:
substoichiometric combustion, i.e. using a fuel-rich mixture so that oxygen is a limiting factor
(fuel acts also as reducing agent),
suprastoichiometric combustion, i.e. using a fuel-lean mixture to dilute combustion heat,
injecting cooled oxygen-depleted fuel gas to dilute combustion heat,
injecting cooled oxygen-depleted fuel gas with added fuel to dilute combustion heat, to reduce
the reaction temperature and to make oxygen a limiting factor,
injecting water or steam to dilute combustion heat and to reduce the reaction temperature.
Reducing residence time at peak temperature: As thermal NOx formation depends largely on the
time the fuel gas remains in the high temperature region, reducing this residence time reduces also
NOx formation. Methods to reduce residence time include [1]:
injection of fuel, steam, re-circulated flue gas or combustion air immediately after combustion,
reducing the extension of the high temperature zone which can be faster left by the flue gas
then.
Chemical reduction of NOx during combustion process: NOx can be reduced to N 2 using a
reducing agent which is itself oxidized. The principle of chemical reduction is widely used in secondary
measures but can be also used as a primary measure when reduction takes already place during the
combustion process. Main methods are:
substoichiometric combustion, i.e. in a fuel rich mixture so that the remaining fuel may act as
reducing agent,
re-burning of the flue gas with fuel added (with the added fuel acting as a reducing agent),
generation of fuel-lean and fuel-rich conditions in the combustion zone.
Reducing nitrogen in the combustion process: Reducing NOx formation by reducing the available
nitrogen can be achieved using nitrogen poor fuels like natural gas (see fuel switch) as well as by
using oxygen instead of air for the combustion process.
The following primary measures which are based on the principles and methods described above are
mainly in use, each with its specific advantages and disadvantages, cf. e.g [1], [11]. Some of the
primary measures are typical for retrofit, others for new installations and others are only applicable in
new installations.
low excess air combustion (LEA): In order to ensure complete combustion air is often added
in large excess which may result in higher thermal NOx formation when air nitrogen is oxidized
[2], [3], [4]. Reducing the excess air reduces also NOx formation.
flue gas recirculation (FGR): Re-circulating cooled flue gas reduces the combustion
temperature in a secondary combustion stage and also oxygen concentration so that thermal
NOx formation is reduced. Heat of the flue gas may be recovered in a heat exchanger [1], [5].
air staging (AS): The principle of air staging is to create two zones, one fuel-rich zone where
initial combustion takes place and a second one where air is added to ensure complete
combustion. This allows reducing thermal NOx formation in the first zone where less nitrogen is
available and in the second where temperature is lower. The zone may be created in different
ways. In Biased Burner Firing (BBF) air and fuel flow rates are varied, in Burners Out of
Service (BOOS) the fuel flow to the burner is cut for a short time and in Overfire Air (OFA) air

is injected above the normal combustion zone [3], [4], [5]. Staged air combustion is frequently
used in conjunction with Low NOx burners (LNB).
fuel staging (FS): Fuel staging is similar to air staging but with fuel instead of air. The first
stage is extremely fuel-lean which reduces the temperature. Fuel added in the second stage
acts as a reducing agent for formed NOx. In a third stage air is added to ensure burnout [6].
fuel re-burning (FR): Fuel re-burning is similar to flue gas recirculation (FGR) but with added
fuel in the flue gas leading to lower temperatures. If added in a second combustion stage fuel
re-burning makes use of the fuel as reducing agent and is similar to fuel staging (FS).
reduced air preheat (RAP): Combustion air is in general preheated by the flue gases to cool
them down in order to improve efficiency. Reducing this preheating reduces also flame
temperature and hence NOx formation but also overall energy efficiency [1], [3].
low NOx burners (LNB): Low NOx burners mix fuel and air/flue gas in a way so that different
zones are created as in staged combustion. The zoning allows lower flame temperature and
oxygen concentration as well as chemical reduction of NOx by fuel in some of the zones [1], [5].
Low NOx burners can be further differentiated into air-staged LNB, flue-gas recirculation LNB
and fuel-staged LNB depending on the principle used for reducing NOx emissions. A further
development is the Ultra low NOx burner.
water/steam injection: Water and steam are injected to cool the flame and to reduce thermal
NOx formation.
oxycombustion: In oxycombustion the combustion air is replaced by oxygen so that no thermal
NOx is produced. So far oxycombustion is to a larger extent only applied for glass production
but its use might become more emerging in future as oxycombustion is one option to achieve
high CO2 concentrations in flue gas which is an advantage for CO2 capture and sequestration
[7].
combustion optimisation: In combustion optimisation the combustion process is actively
controlled, e.g. by making use of specialised software. One option is to slightly decrease
combustion efficiency in order to reduce NOx emissions [1].
catalytic combustion: Using a catalyst to reduce combustion temperature below NOx
formation temperature may reduce NOx emissions very strongly. However, applications are still
rare in practice [1] though gas turbines seem to be an interesting field of application [8].
The techniques reported in § 4.4 are an inventory of available technologies to reduce NOx emissions,
which does not mean that those reported technologies are applicable to each industrial sector or
process of production.
For new stationary gas and diesel engine measures, refer to document 7-41.
4.5 Secondary measures

Secondary measures (add-on or end of pipe technologies) reduce the emissions of already formed
NOx to the environment.
There are two main principles:
chemical reduction of NOx by a reducing agent with or without a catalyst,
sorption/neutralisation of NOx.
The following secondary measures are mainly in use, each with its specific advantages and
disadvantages [1]:
selective Catalytic Reduction (SCR): In SCR, NOx is reduced to N2 by a reducing agent
(usually ammonia) which is directly injected into the flue gas over a catalyst in the presence of
sufficient oxygen. NOx-conversion takes place on the catalyst surface at a temperature between
170 and 510 degree C (with a range between 300 and 400 degree C being more typical, the
minimum flue gas temperature is dependent on the sulphur content of the fuel. At a too low flue
gas temperature ammonium bisulphate is formed which will clog the SCR elements. A limitation
for the applicability of SCR [11] exists for diesel engines which need to be operated in varying
loads. These units are operated frequently on isolated systems to be operated for a reduced
number of hours only. According to the electricity demand, these engines need to be started up
and shut down several times a day. SCR is an applied technique for diesel engines, but cannot
be seen as BAT for engines with frequent load variation, including frequent start up and shut

down periods due to technical constraints. A SCR unit would not function effectively when the
operating conditions and the consequent catalyst temperature are fluctuating frequently outside
the necessary effective temperature window. As a result, SCR is part of BAT, but no specific
emission levels are associated with BAT in a general sense.
selective Non-Catalytic Reduction (SNCR): Similar to SCR a reducing agent (usually
ammonia, urea or caustic ammonia) is used to reduce NOx but in contrast to SCR, without a
catalyst and at a higher temperature between 850 and 1100°C.
Other secondary NOx control techniques include:
NOXSO Process: The NOXSO process is based on simultaneous adsorption of SO 2 and NOx
from flue gas by a regenerable sorbent, finally leading to liquid SO 2, N2 and O2. Claimed
efficiencies are 98% for SO 2 and 75% for NOx [9].
SOx-NOx-Rox-Box (SNRB): SNRB uses a catalytic baghouse for integrated removal of SOx
(via injection of alkali sorbent), NOx (via ammonia injection and SCR), and dust (cf 10).
Problems with this technique include the production of hazardous waste as by-product and
rather low abatement efficiencies.
limestone Injection Multistage Burner (LIMB): LIMB shows lower reliability and rather low NOx
abatement efficiencies.
In integrated gasification combined cycle (IGCC) the fuel is gasified under reducing conditions to
syngas. The syngas is then cleaned and burnt in either air or oxygen. This enables to achieve very low
NOx emission levels. IGCC is seen as one of several key technologies in the framework of carbon
capture and storage (CCS). So far its application is restricted to few, mostly demonstration plants.
With CCS, IGCC could become commercially available around 2020 .
The selection of the most suitable measure depends on many factors related to e.g. [11]:
fuels used,
combustion technology applied,
operational mode of installation,
process characteristics in industrial processes,
new installation or retrofitting,
flue gas characteristics (NOx concentration, temperature, humidity, dust, other pollutants,
catalyst poisons etc.),
flow rate of flue gas,
emission levels to be achieved,
side and cross media effects,
operational safety and reliability,
costs.
The following table gives a brief overview about the performance of primary and secondary measures
for reducing NOx emissions in large combustion plants; cf. the sectoral chapters for more detailed
information on sector specific issues.

Table 5: average reduction efficiency of selected primary and secondary measures for
reducing NOx emissions in large combustion plants for boilers [11]
Technique Average NOx reduction rate* Technical limitations

Low excess air (LEA) 10-44% incomplete burn-out
Burner out of service (BOOS) 10-70% incomplete burn-out
Biased burner firing (BBF)
Overfire air (OFA)
Flue gas recirculation (FGR) < 20% (coal) flame instability
30-50% (gas, combined with OFA)
Reduced air preheat (RAP) 20-30%
Fuel staging (FG) 50-60%
Air-staged LNB 25-35% incomplete burn-out
flame instability
Flue-gas recirculation LNB <20% flame instability
Fuel-staged LNB 50-60% incomplete burn-out
flame instability
Selective catalytic reduction 80-95% ammonia slip;
(SCR) contamination of fly ash by
ammonia; air heater fouling
Selective non-catalytic reduction 30-50% ammonia slip which is
(SNCR) usually higher than with
SCR
* If several measures are applied reduction rates are different.
4.6 Costs of NOx emission reduction techniques

Costs are an important issue when selecting NOx emission reduction techniques. The following
expenses may be relevant [12]:
labour costs,
energy costs,
often more cost-effective. Retrofitting of existing installations is often possible but in general at higher
costs.
For primary measures, investment related costs are in general relatively low and in new installations
there are often no additional costs. But costs accruing from efficiency decreases may be significant
and have to be accounted for.
For SCR, the cost of retrofitting may be high because of the difficulty of building a catalyst reactor
close to the boiler. In addition, for SCR the following costs are most relevant: investment related costs,
ammonia costs, electricity costs, catalyst replacement costs and labour costs. SNCR generally has
lower costs than SCR as there are no costs for catalysts and catalyst reactor housings. However,
costs for SCR and SNCR depend e.g. on the nature of the waste gas, its temperature and the required

abatement efficiency. As a consequence, the additional costs for catalyst replacement in the case of
SCR may be compensated by a significantly lower ammonia consumption compared to SNCR.
4.7 Side effects

accounted for. Side effects can generally be reduced by properly designing and operating the facilities.
Side effects include
impacts on use of natural resources,
More specifically, the side effects to be considered with different emission reduction techniques are:
Primary measures: possible side effects are lower overall energy efficiency, increased CO and
soot formation and hydrocarbon emissions, corrosion due to reducing atmosphere, increase in
unburnt carbon in fly ash.
FBC: this technique also brings about a considerable reduction in SO x emissions. A possible
drawback in FBC systems may be the increased formation of N2O under certain process
conditions. The handling of the ashes needs consideration in relation to their possible use
and/or disposal.
SCR: some possible side effects are ammonia slip in the exhaust gas, ammonia content in the
fly ash, formation of ammonium salts on downstream facilities, deactivation of the catalyst and
increased conversion of SO2 to SO3 (corrosion and fouling). By the controlled operation of the
plant, the fly ash quality can, however, be guaranteed and the formation of ammonia salt
reduced. In terms of by-products, deactivated catalysts from the SCR process may be the only
relevant products, although this has become a minor problem since catalyst lifetime has been
improved and reprocessing options exist. Biomass and waste burning can reduce catalyst life.
SNCR: side effects to be considered are ammonia in the exhaust gas, formation of ammonium
salts on downstream facilities, the formation of N 2O, when urea, for instance, is used as a
component of the reducing mixture, and CO releases. The ammonia slip from SNCR usually is
much higher than from SCR due to the required over-stoichiometric dosage of the reducing
agent (at the high temperatures required for SNCR, part of the injected ammonia reacts to form
additional NOx).
The production of ammonia and urea for flue gas treatment processes involves a number of
separate steps which require energy and reactants. The storage systems for ammonia are subject to
the relevant safety legislation and such systems are designed to operate as totally closed systems,
with a resultant minimum of ammonia emissions. The use of NH 3 is still considered appropriate, even
when taking into account the indirect emissions related to the production and transport of NH 3.

[1] US EPA (1999): Nitrogen Oxides, Why and how they are controlled? U.S. Environmental Protection
Agency (EPA), Technical Bulletin EPA-456/F-99-006R.
[2] Lim, K.J., C. Castaldini, and C.D. Wolbach (1982): A promising NOx-Control Technology. –
Environmental Progress 1, 167-177.
[3] Wallin, S.C. (1986): Abatement systems for SOx, NOx, and Particles – Technical Options. – The
Environmentalist 6, 111-124.
[4] A summary of NOx reduction technologies. – The Texas Institute for Advancement of Chemical
Technology Special Report 1, 2000.
[5] Lani, B.W., T.J. Feeley, J. Murphy, and L. Green (2005): A review of DOE/NETL’s advanced NOx
control technology R&D program for coal-fired power plants. – DOE/NETL’s NOx R&D Program
Review, March 2005.

[6] Zabetta, E.C., M. Hupa and K. Saviharju (2005): Reducing NOx emissions using fuel staging, air
staging, and selective non catalytic reduction in synergy. – Ind. Eng. Chem. Res. 44, 4552-4561.
[7] Results of work of the EGTEI expert sub-group on Emerging Technologies/Techniques. Report by
the Chair of the Expert sub-group on Emerging Technologies/Techniques to the Working Group on
Strategies and Review – 1 – 5 September 2008.
[8] Cocchia, S., G. Nutinia, M.J. Spencerb and S.G. Nickola (2006): Catalytic combustion system for a
10 MW class power generation gas turbine. – Catalysis Today 117, 419-426.
[9] Black, J.B., M.C. Woods, J.J. Friedrich, and J.P. Browning: The NOXSO clean coal project. -
NOXSO Corporation, PA, USA.
[10] Kudlac, G. A., G.A. Farthing, T. Szymanski, and R. Corbett (1992): The SOx-NOx-Rox BoxTM
(SNRB). - Environmental Progress, 11, 33 – 38.
[12] VDI 3800, Determination of costs for industrial environmental protection measures. Verein
Deutscher Ingenieure, 2001.
[13] EGTEI: Final background document on the sector “glass industry”, DFIU/IFARE 2003.

5 General issues for VOCs

5.1 General issues
Definitions
Volatile organic compounds or VOCs means, unless other wise specified, all organic compounds of an
anthropogenic nature, other than methane, that are capable of producing photochemical oxidant by
reaction with nitrogen oxides in the presence of sunlight.
An organic compound is any compound containing at least the element carbon and one or more of
hydrogen, halogens, oxygen, sulphur, phosphorus, silicon or nitrogen, with the exception of carbon
oxides and inorganic carbonates and bicarbonates [1].
On case by case, other definitions can be encountered in sectoral the sections of chapter 7s:
For the uses of solvent considered in chapter 7-24 to 7-37 and technical annex VI, volatile organic
compounds (VOC) mean any organic compound as well as the fraction of creosote, having at 293.15
K, a vapour pressure of 0.01 kPa or more, or having a corresponding volatility under the particular
conditions of use [9].
For the solvent content of products, chapter 7-38 and technical annex XI, volatile organic compounds
(VOCs) means any organic compound having an initial boiling point less than or equal to 250°C
measured at a standard pressure of 101.3 kPa. This definition is compatible with the previous one, as
there is a relation between the boiling point and the vapour pressure.
The leak detection and repair programme (LDAR) [3] developed by the US EPA and standardised in
Europe [4] is based on a vapour pressure of VOCs of 300 Pa at 295.15 K.
VOCs result from a larger number of sources both anthropogenic and natural:
thermal processes: hydrocarbons emitted from thermal processes (fixed sources and mobile
sources) contribute to the total amount of VOCs,
use of organic solvent: an organic solvent is any VOC which is used alone or in combination
with other agents, and without undergoing a chemical change, to dissolve raw materials,
products or waste materials, or is used as a cleaning agent to dissolve contaminants, or as a
dissolver, or as a dispersion medium, or as a viscosity adjuster, or as a surface tension
adjuster, or a plasticiser, or as a preservative [1],
transport and handling of liquid fuels and light organic compounds (petrol as example),
refineries and organic chemical industries,
natural sources.
VOCs play a significant role in the atmospheric chemistry. VOCs, through complex photochemical
reactions, contribute to the formation of toxic oxidants, such as tropospheric ozone and other oxidants,
which can trigger a variety of health problems and have detrimental effects on plants and ecosystems.
Certain VOCs have been shown to be highly toxic, mutagenic and carcinogenic. These VOCs have to
receive increased attention due to their implication for human health. These VOCs are those affected
by the following risk phrases [7]:
H 350: may cause cancer;
H 340: may cause genetic defects;
H 350i: may cause cancer by inhalation;
H 360F: may damage fertility;
H 360D: may damage the unborn child.
These VOCs should be reduced as far as possible in priority. VOCs associated to risk phrases H351
suspected of causing cancerand/or H 341 suspected of causing genetic defects, should be also
considered with attention and reduced as far as possible.

In order to reduce efficiently VOC emissions, it is of particular importance to consider both the
reduction of stack emissions and fugitive emissions. Stack emissions refer to emissions of which the
source and the direction of gas flow is clearly definable. They enter in the atmosphere by passing
through a stack or a duct designed to direct and control their flow. Sources of fugitive emissions are
not clearly defined. They enter in the atmosphere without passing through a stack or duct designed to
direct or control the emissions. They include uncaptured emissions released to the outside
environment via windows, doors, vents and similar openings [2]. In industrial plants, fugitive emissions
have a diffuse character as they can arise from a lot of sources spatially dispersed.
Instead of applying emission limit values (ELV), e.g. connected to end-of-pipe measures, reduction
schemes can be used. Solvent management plans have to be used as guidance for these reduction
schemes. The purpose of a reduction scheme is to allow a plant operator to achieve emission
reductions similar to those achieved if given limit values were to be applied by other means.
Definitions of solvent management plan and of a reduction scheme are given below. Solvent
management plan and reduction scheme are a key element of annexe VI to the Protocol to Abate
Acidification, Eutrophication and Ground-level Ozone. They help to verify compliance with given
regulations, identify future reduction options, and enable the provision of information on solvent
consumption, emissions and compliance with regulations to the public.
In this guidance document, emission abatement options/techniques are characterised by:

emission factors expressed in terms of mass of emitted substance (VOCs) or mass of total
2
organic carbon per activity within a sector (e.g. g/m in car coating); or
emission factors expressed in terms of mass of emitted substance (VOCs) or mass of total
organic carbon per mass of solvent input (solvent purchased + solvent recovered and reused)
within a sector (e.g. % of solvent used in speciality organic chemistry); or
concentrations in terms of mass of emitted substance (VOCs) or total organic carbon per
volume unit of the exhaust gases; or
abatement efficiency (%).
In general, no further subdivision for VOCs is made with regard to specific substances. Performance is
reported where available.
5.2 Knowledge of emissions and solvent management plan

In order to minimise VOC emissions and construct a reduction plan, perfect knowledge of emissions is
essential. This knowledge is based on monitoring VOC emissions in stacks, determining VOC fugitive
emissions by several relevant techniques.
A solvent management plan is a key technique to understand the consumption, use and emissions of
solvents, especially fugitive VOC emissions [5].
The solvent management plan consists in estimating solvent inputs and solvent outputs. Inputs are
often easily known. On contrary, some outputs cannot be estimated easily. The solvent mass balance
is a tool for estimating VOC emissions based on the following principles [1].
Definitions of inputs and outputs to be considered are as follows:
Inputs of organic solvents (I):
I1 The quantity of organic solvents or their quantity in preparations purchased which are used as input
into the process in the time frame over which the mass balance is being calculated.
I2 The quantity of organic solvents or their quantity in preparations recovered and reused as solvent
input into the process. (The recycled solvent is counted every time it is used to carry out the activity.)
Outputs of organic solvents (O):
O1 Emissions in waste gases.
O2 Organic solvents lost in water, if appropriate taking into account waste water treatment when
calculating O5.
O3 The quantity of organic solvents which remains as contamination or residue in products output
from the process.

O4 Uncaptured emissions of organic solvents to air. This includes the general ventilation of rooms,
where air is released to the outside environment via windows, doors, vents and similar openings.
O5 Organic solvents and/or organic compounds lost due to chemical or physical reactions (including
for example those which are destroyed, e.g. by incineration or other waste gas or waste water
treatments, or captured, e.g. by adsorption, as long as they are not counted under O6, O7 or O8).
O6 Organic solvents contained in collected waste.
O7 Organic solvents, or organic solvents contained in preparations, which are sold or are intended to
be sold as a commercially valuable product.
O8 Organic solvents contained in preparations recovered for reuse but not as input into the process,
as long as not counted under O7.
O9 Organic solvents released in other ways.
Determination of solvent consumption and NMVOC emissions can be done according to equations
presented here after:
Consumption can be calculated according to the following equation:
C = I1 - O8
Total NMVOC emissions are defined as follows:
E = F + O1
Where F is the fugitive emission as defined below:
F = I1 - O1 - O5 - O6 - O7 - O8
or
F = O2 + O3 + O4 + O9
This quantity can be determined by direct measurement of the quantities. Alternatively, an equivalent
calculation can be made by other means, for instance by using the capture efficiency of the process.
The fugitive emission value as well as the total emission can be expressed as a proportion of the
input, which is calculated according to the following equation:
I = I1 + I2
The solvent management plan can be done on a regular basis such as an annual basis, in order to
control progress carried out, take the necessary measures if deviations are observed and be in
position to assess the compliance of the installation with regulation implementing ELVs.
5.3 General approaches to reduce VOCs emissions

For nearly all stationary sources, measures to control or to prevent VOCs emissions are available. A
distinction is generally made between primary, secondary (add-on or end-of-pipe) and structural
measures. Unless stated otherwise, measures are applicable to new and existing installations. The
reduction of VOC emissions outside of stationary sources focuses on the restrictions in the VOC
content of products.
The following list gives a general outline of available measures for reducing VOC emissions, which
may also be combined with secondary measures:
(a) More effective VOC control technologies in terms of efficient maintenance of equipment, better
capture of waste gases, and generally optimized operating conditions;
(b) Substitution of VOC, e.g. use of low-organic solvent or organic-solvent-free materials and
processes, such as water-based paints, water-based degreasing, etc., and/or process modifications;
(c) Reduction of emissions by best management practices such as good housekeeping, improved
inspection and maintenance programmes, by changes in processes such as closed circuit machines,
improved sealing of storage tanks, or by structural changes such as transfer of activity to locations
where VOC emissions are reduced more efficiently, e.g. via pre-coating of certain products;
(d) Recycling and/or recovery of VOCs by control technologies such as condensation, adsorption,
absorption, and membrane processes (pre-processing step). A further option is the recovery of heat
(energy recovery) from VOCs. Preferably, the organic compounds should be reused on-site; this can

be facilitated by the use of only few organic solvents instead of complex mixtures. Complex mixtures
may be better treated off-site; however, emissions may be caused by distribution, handling, transport
and storage;
(e) Destruction of VOCs by control technologies such as thermal or catalytic incineration, or
biological treatment. For incineration, heat recovery is recommended in order to reduce operating
costs and resource consumption. Another common procedure for destroying non-halogenated VOCs
is to use VOC-laden gas streams as secondary air or fuel in existing energy-conversion units.
5.3.1 Primary measures

Possible primary measures for the control of emissions from the industrial use of organic solvents are:
prevention (use of low- or no-organic solvent containing materials and processes), good
housekeeping, process-integrated measures and structural measures. Thus, two approaches can in
principle be used: a product-oriented approach, which, for instance, leads to a reformulation of the
product (paints, inks, degreasing products, etc.); and process-oriented changes (increase of transfer
efficiency, use of sealed chamber systems for degreasing…); , other); Moreover, the product-oriented
approach should be looked at, inter alia, because of the positive spin-off effects on emissions from the
organic solvents manufacturing industry. Moreover, the environmental impact of emissions can be
reduced by product reformulation to replace solvents by less harmful alternatives. Closed systems
may lead to very low organic solvent emissions as well. There is a rapid ongoing development towards
low-organic solvent or organic-solvent-free paints, which are among the most cost-effective solutions.
For the domestic use of paints and other solvent-containing products, only a product-oriented
approach is possible. The same is true for the painting of constructions and buildings, the commercial
use of cleaning products, etc. The use of water-based systems (e.g. for paints and adhesives) is an
effective measure already used, especially for products for both commercial and domestic purposes.
5.3.2 Secondary measures

When primary measures are not sufficient to reach high VOC reductions or are not technically
applicable, add-on control technologies can be applied alone or in combination. These techniques are
used to reduce VOC emissions from processes and solvent uses.
The following techniques can be distinguished:

techniques based on destruction of VOCs present in waste gases:
- recuperative or regenerative thermal oxidation,
- catalytic recuperative or regenerative oxidation,
- biological destruction.
techniques enabling possible recovery of VOCs for possible reuse in the process after a specific
treatment carried on site or by external companies:
- adsorption on activated carbon or zeolithe substrates,
- absorption in adapted scrubbing liquors (water, heavy oils),
- condensation and cryogenic condensation,
- membrane separation associated to other processes such as cryogenic condensation and
adsorption.
Processes using thermal oxidation may enable valorisation of the energy content of VOCs. However,
in most cases, this valorisation is difficult due to the low VOC concentrations generally encountered.
Primary thermal energy recovery (for warming inlet gases as example) is indispensable but secondary
thermal energy recovery is often most difficult to be implemented in existing plants. The VOCs
concentrations have to be sufficient for enabling the oxidation unit to run without additional fuel
consumption and to be consequently in autothermal conditions. Lower concentrations require
additional fuel consumption which can be rapidly prohibitive.

Recuperative or regenerative thermal oxidation. In recuperative or regenerative oxidation, VOCs

are destructed at high temperature. The oxidation temperature depends on the type of energy
recovery system used. In recuperative oxidiser, a preheating thermal exchanger is used to heat inlet
gases. The heat recovery ranges from 60 to 70 %. The temperature ranges from 650 to 750°C. The
3
system can only be autothermal for high concentrations of VOCs ranging from 8 to 10 g/Nm . The
regenerative thermal oxidiser is constituted of two or three ceramic heat exchangers. Waste gases
containing VOCs pass through a first ceramic exchanger. They are heated. They enter after in the
combustion chamber maintained at about 800 to 900 °C by burners. Before being released into the
atmosphere they leave the oxidiser through another ceramic exchanger, transferring its thermal
energy to be re-used for preheating the next cycle. The role of the exchanger, heating or cooling, is
inversed regularly. Heat recovery efficiency up to 95 % can be achieved. Regenerative thermal
oxidisers are suitable for large waste gas flow rates and can be autothermal at VOCs concentrations
3 3
from 2 to 3 g/Nm . Output VOC concentrations lower than 20 mg/Nm can be achieved in perfectly
dimensioned and operated oxidisers. Methane is largely represented in the resulting concentrations.
Recuperative or regenerative catalytic oxidation. In recuperative or regenerative catalytic

oxidation, the use of a catalyst enables VOCs to be destroyed at lower temperature than in thermal
oxidation. Catalysts used are either precious metals (Platinum, Palladium or rhodium) or metal oxides
(Cr, Fe, Mo, Mn, Co, Cu, Ni). The principles of heat exchange are the same as in thermal oxidation.
Oxidation temperatures range from 200 to 500 °C according to catalyst used and the type of heat
exchanger used. Recuperative catalytic oxidiser can be autothermal at concentrations ranging from 3
3
to 4 g/Nm . Regenerative catalytic oxidiser can be autothermal at concentrations ranging from 1 to 2
3
g/Nm . Life time of catalysts is limited. Lifetime of metal oxide based catalysts is about 12 000 h. Life
time of precious metal based catalysts is about 15 000 h to 25 000 h. Catalysts are sensible to
poisons and they can be deactivated irreversibly by certain of them. Output VOC concentrations lower
3
than 20 mg/Nm can be achieved in perfectly dimensioned and operated oxidisers. When using liquid
fuels with more than 0.1% S in the power plant prime mover, the catalyst lifetime can be shortened.
Methane is largely represented in the resulting concentrations.
Biological destruction: biological destruction can be carried out in bio filters and in bio scrubbers.
Micro organisms are able to destruct biodegradable VOCs in humid conditions and at low
temperature. Warm waste gases (> 35 °C) must be cooled. In bio filter, microorganisms are
maintained at the surface of a moist organic substrate which can be peat, heather or compost. In bio
scrubbing, a combination of wet gas scrubbing and biodegradation is carried out. Microorganisms are
suspended in the scrubbing water. In biofilters, residence time must be sufficient to enable biological
reactions to occur. Accepted inlet VOC concentrations are low. Biological oxidation is used primarily
3
for low concentrations. Output VOC concentrations from 100 to 150 mg/Nm can be achieved. Lower
concentrations are however more difficult to obtain.
Adsorption on activated carbon or zeolithes. In adsorption, VOCs are physically bound to the
surface of a media which can be activated carbon or zeolithes. The adsorption capacity of activated
carbon or zeolithe is limited and consequently they must be regenerated to recover their initial
capacity to adsorb VOCs and recover VOC. Several configurations exist but in most of the cases,
fixed bed adsorption devices are used with 2 or 3 beds. A bed is in adsorption phase, the second one
is in desorption phase. Desorption is carried at high temperature with steam or inert gas. The
adsorption temperature must be below 40 °C because the effectiveness of adsorption improves at low
temperature. Inlet gases must be consequently conditioned. VOCs are recovered after a special
treatment which involves condensation, separation and distillation if several VOCs are present. VOCs
abatement efficiency depends on a lot of parameters such as adsorption temperature, type and
number of VOCs to be eliminated, frequency set point for desorption. Output VOC concentrations from
3
50 to 100 mg/Nm can be achieved. Efficiencies achieved depend on numerous factors such as
correct dimensioning of the installation, the frequency of desorption and the threshold value fro for
desorption….
Condensation and cryogenic condensation: in condensation VOCs are cooled below the stream
dew point. Condensation of VOCs is carried out by chilling and /or pressurisation. Cooling media can
be cooled water, chilled water, refrigerants and liquid nitrogen. Diverse heat exchangers equipment
can be used. Condensation with cooled water, chilled water or refrigerants is often used as pre-

treatment but is not sufficient to achieve high reduction of emissions. Output VOC concentrations from
3
100 to 150 mg/Nm can be achieved. Efficiencies achieved depend on numerous factors such as
correct dimensioning of the installation, the frequency of desorption and the threshold value for
desorption…
Liquid nitrogen is used in cryogenic (temperature less than -160°C) condensation. Cryogenic
condensation is a versatile process that is not VOCs specific. Typically, condensation takes place with
liquid nitrogen as the refrigerant in a straightforward heat exchange process. The VOCs condense on
the shell side of the exchanger then drains into a collection tank, from which it can be recycled,
reclaimed, recovered for reuse or for disposal. During condensation, the presence of water vapour or
VOCs with a high melting point can cause freezing on the external surface of the tubes inside a
cryogenic condenser. Special configuration exists to avoid this problem and especially a series of
condenser can be used with different temperature set points [8]. Cryogenic condensation is best
suited to low waste gas flowrates and/or high VOCs concentrations. Output VOC concentrations from
3
50 to 100mg/Nm can be achieved. Efficiencies achieved depend on numerous factors such as correct
dimensioning of the installation, the volatility of solvents…
Membrane separation: VOC emissions can be concentrated using organic selective (VOCs
permeable) membranes. Air and VOCs permeate through the membrane at rates determined by their
relative permeabilities and the pressure difference across the membrane. Membranes ar e typically 10
to 100 times more permeable to VOCs than air, depending on the specific VOC characteristics. Based
on the system design, the exit membrane stream VOC concentration can be increased five to fifty
times the inlet membrane stream concentration. Concentrated gas streams can be then compressed
and condensed by the use of conventional condensation technology. Membrane separation cannot be
used alone. Subsequent gas cleaning device is necessary.
The choice of a control technique will depend on various parameters, such as the concentration of
VOCs in the raw gas, the gas volume flow, the type and composition of VOCs, and others. Therefore,
some overlap in the fields of application may occur. In that case, the most appropriate technique must
be selected according to case-specific conditions. An overview of the most relevant parameters for the
application of some secondary measures is outlined in table 26. The overall efficiency of secondary
measures in the solvent-using sectors depends to a large extent on the capturing efficiency for the
VOC-laden waste gas flows. Especially for fugitive emissions, capturing is paramount for the overall
efficiency of the system.

Table 6: overview of the most relevant parameters for the application of secondary measures
Thermal Thermal Catalytic Catalytic

recuperative regenerative recuperative regenerative
oxidation oxidation oxidation oxidation
Ranges of Adapted to high Adapted to low Adapted to low Adapted to very low
concentrations concentrations concentrations concentrations concentrations
3 3 3 3
5 to 20 g/Nm 2 to 10 g/Nm 2 to 10 g/Nm C < 5 g/Nm
Waste gas flow 1 000 to 30 000 10 000 to 200 000 1 000 to 30 000 10 000 to 100 000
3 3 3 3
rates Nm /h Nm /h Nm /h Nm /h
Authothermic 3 3 3 3
8 to 10 g/Nm 2 to 3 g/Nm 3 to 4 g/Nm 1 to 2 g/Nm
threshold
Performances
3 3 3 3
VOCs (C eq) < 20 mg/Nm < 20 mg/Nm < 20 mg/Nm < 20 mg/Nm
1 3 3 3 3
NOx < 100 mg/Nm < 50 mg/Nm < 50 mg/Nm < 50 mg/Nm
3 3 3 3
CO < 100 mg/Nm < 50 mg/Nm < 50 mg/Nm < 50 mg/Nm
Limits of uses Low concentrations Presence of Presence of Presence of
Presence of halogenated halogenated halogenated
halogenated organic organic organic
organic compounds ; compounds ; compounds ;
compounds ; Presence of Presence of catalyst Presence of catalyst
Energy particulate matter ; poisons ; poisons ;
consumption . Presence of Presence of
outside autothermal Particulate matter ; Particulate matter ;
conditions. Risks of high Risks of high
concentrations concentrations
Biological Adsorption on Absorption in heavy Cryogenic

destruction activated carbon oil condensation
Ranges of Adapted to very low
concentrations concentrations 3 3 3
C < 15 g/Nm C < 10-15 g/Nm C > 10 g/Nm
3
C < 1 à 2 g/Nm
Waste gas flow 1 000 à 100 000 1 000 to 100 000 1 000 to 100 000 1 000 to 5 000
3 3 3 3
rates Nm /h Nm /h Nm /h Nm /h
Performances (C 3 3 3 3
100-150 mg/Nm 50 to 100 mg/Nm 50 to 100 mg/Nm 50 to 100 mg/Nm
eq)
Limits of uses non biodegradable Number of VOCs Number of VOCs Number of VOCs
VOCs, Presence of Capacity of High volatile
Temperature of particulate matter ; absorption of compounds
waste gases to be Presence of VOCs; Humidity ;
treated polymerisable Treatment of Treatment of
Non permanent compounds ; recovered products. recovered products.
release of NMVOC. Treatment of
recovered products.
1
Concentrations obtained for oxidisers used to abate VOC emissions from solvent uses in processes.
5.4 Costs
The estimation of investments and operating costs for VOC emission reduction options/techniques is
important when choosing from the wide range of measures and, on a macroeconomic level, when
developing a national or regional emission control strategy. It must be borne in mind that specific
figures are highly dependent on factors such as plant capacity, removal efficiency, VOC concentration
in the raw gas, type of technology, and the choice of new installations as opposed to retrofitting. These
parameters, and thus the costs incurred as well as the resulting ranking of measures in terms of costs,
may be highly case-specific, for instance for retrofit cases, and examples should not be generalised.

EGTEI documents defining the methodologies used to estimate costs for waste gas treatment
techniques are available. Documents on oxidation, carbon adsorption and bio filtration are available at:
http://citepa.org/forums/egtei/egtei_doc-VOC_abattement_tech.htm.
Investments and operating costs depend particularly on flow rates and VOC concentrations to be
treated. Costs are provided in chapter 7.
5.5 Side effects

accounted for. Side effects can generally be limited by properly designing and operating the facilities.
Side effects include:
impacts on the use of natural resources,
Table 7: positive and negative side effects of VOC emission reduction techniques Mis en forme : Non Surlignage
Reduction technique Positive side effects Negative side effects Mis en forme : Non Surlignage
Oxidation Possible co-treatment of odours Energy consumption and GHG

emissions in case of non
autothermal conditions
Adsorption Possible co-treatment of odours Possible increase of energy
consumption for steam
generation
Cryogenic condensation Possible co-treatment of odours Energy consumption to produce
liquid nitrogen

[1] Council Directive 1999/13/EC of 11 March 1999 on the limitation of emissions of volatile organic
compounds due to the use of organic solvents in certain activities and installations
Official Journal L 085, 29/03/1999 P. 0001 - 0022
[2] Directive 2004/42/CE on the limitation of emissions of volatile organic compounds due to the use o f
organic solvents in certain paints and varnishes and vehicle refinishing products and amending
Directive 1999/13/EC
[3] US EPA - Protocol for equipment leak - Emission estimates
EPA 453-95-017 – 1995
[4] EN 15446:2008
"Fugitive and diffuse emissions of common concern to industry sectors - Measurement of fugitive
emission of vapours generating from equipment and piping leaks"
European comity of normalisation
[5] European Commission - reference document on BAT in surface treatment with solvent 2007
[6] European Commission - reference document on BAT in common waste water and waste gas
treatment / management systems in the chemical sector – February 2003.
[7] Regulation (EC) No 1272/2008 of the European parliament and of the council of 16 December
2008 on classification, labeling and packaging of substances and mixtures, amending and repealing
Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006
[8] Joint Service Pollution Prevention and Sustainability Technical Library
http://205.153.241.230/topics/airpollution.html

6 General issues for dust (including PM10, PM2,5 and BC).

6.1 General issues
Dust refers to a complex mixture of small to tiny particles and liquid droplets suspended in air. Sizes of
dust range from several nanometers up to 100 micrometers (µm). Dust may be differentiated
according to the aerodynamic diamete,r into:
large particles with an aerodynamic diameter of more than 10 µm,
coarse particles with an aerodynamic diameter of 2.5 to 10 µm,
fine particles with an aerodynamic diameter of less than 2.5 µm,
ultrafine particles with an aerodynamic diameter of less than 0.1 µm,
and more particularly into:
Total Suspended Particles (TSP) as the sum of fine, coarse and large particles,
PM10: the mass of particulate matter that is measured after passing through a size-selective
inlet with a 50 % efficiency cut-off at 10 μm aerodynamic diameter,
PM2.5: the mass of particulate matter that is measured after passing through a size-selective
inlet with a 50 % efficiency cut-off at 2.5 μm aerodynamic diameter;
PM1: the mass of particulate matter that is measured after passing through a size -selective inlet
with a 50 % efficiency cut-off at 1 μm aerodynamic diameter.
Besides this size dependent classification, dust is also differentiated according to its origin into primary
and secondary dust. Dust can be natural (sea salts, volcanoes, soil erosion...) , etc) and
anthropogenic (combustrion, processes...). , etc). According to its source, dust has different chemical
compositions. Primary dust is composed of salts (nitrates, sulphates, carbonates...), , etc), of black
carbon (BC), of organic carbon (non-carbonate carbonaceous particles other than elemental carbon
[20]) (OC) and trace elements such as heavy metals. Secondary PM is formed in the atmosphere of
the precursors ammonia, sulphuric acid, nitric acid and NMVOC-related organic oxidation products [1].
Dust affects the radiation balance of the earth. Some components of dust have a cooling effect
(sulphates, OC). Other ones, have a warming effect (BC).
BC means carbonaceous particulate matter that absorbs light. Absorption occurs at all wavelengths of
solar radiation [16], [19]. BC remains in the atmosphere for days to weeks and because of its light
absorbing properties, it contributes significantly to global warming. It also darkens snow and ice after
deposition and thereby reduces the surface albedo, or reflectivity. This albedo effect is particularly
prevalent in the Arctic region. By darkening ice and snow, it contributes to regional warming [16], [17],
[18].
The BC content of dust increases with incomplete combustion of various fossil fuels, biofuels and
biomass [16]. BC is part of a complex particle mixture called soot which primarily consists of BC
(which is a warming agent) and OC (which is a cooling agent). There is a close relationship between
the two compounds. They are always co-emitted, but in different proportions for different sources.
Soot mixtures can vary in composition, having different ratios of OC to BC and usually include
inorganic materials such as metals and sulphates. For example, the average OC/BC ratio of diesel
exhaust could range approximately from 1/4 (heavy duty engine type operating on distillate) according
to reference [19] to 15/1 (large medium speed engine operating on heavy fuel oil) according to
reference [2134]. For biofuel burning, the ratio is approximately 4/1 and for open vegetation fires (or
open biomass burning) it is approximately 9/1 [19]. For all sources, monitoring results are needed to
improve knowledge of BC emissions.
BC forms during combustion, and is emitted when there is insufficient oxygen and heat available for
the combustion process to burn the fuel completely. BC originates as tiny spherules, ranging in size
from 0.001 to 0.005 micrometers (μm), which aggregate to form particles of larger sizes (0.1 to 1 μm).
The characteristic particle size range, in which fresh BC is emitted, also makes it an important
constituent of the ultrafine particles (<100 nanometers (nm)). BC is associated with particles less than
1 µm [19]. When combustion is carried out in optimal O 2 concentrations (optimal excess air) and
optimal temperatures, mainly salts are present in dust. Mitigation techniques for BC are the same as
for PM2,5 as BC is a compound of dust. Only fabric filters and electrostatic precipitators can be
efficiencies on fine particles.

Inhaling dust may cause negative health effects [2] like asthma, lung cancer, cardiovascular issues,
and premature death. Health effects are related to particle size as large particles can be filtered out in
the nose and throat. Particles with a size less than about 10 µm can enter the bronchi and the lungs,
particles less than 2.5 µm in diameter the gas-exchange regions of the lung, and particles less than
0.1 µm can enter via the lungs into other organs. Therefore, the potential for negative health effects
increases with decreasing particle diameter. Besides particle size also the chemical compos ition, e.g.
carcinogenic components, and solubility of the particle in the lung has an impact on the potential
health effects. Health effects are expected to be related to the number of smaller particles whereas
most measurements refer to the particle mass which is in general dominated by the larger particles
within the size fraction.
Furthermore, dust generates haze with effects on visibility.
For dust, there are several natural and anthropogenic sources with differences in the size and the
chemical composition of the generated dust. Dust formation may result from:
mechanical processing of solid matter (crushing, grinding, surface processing, abrasion etc.),
chemical and physical reactions (incomplete combustion, gas-to-particle conversion,
condensation, deposition etc.),
exposure of solid matter (wind erosion etc.)
re-suspension of dust (from roads, stockpiles etc.).
Published measurement data on the share of PM 2.5 and PM10 in waste gas is scarce and/or of limited
quality. Therefore the following tables citing calculated shares as used in the RAINS/GAINS model are
presented.

Table 7: shares of PM2.5 and PM10 in TSP as used in RAINS (2002) [15]
%
Sector Name RAINS-Code(s) Unit PM2.5 PM10 %PM10 TSP
PM2.5
Coal, grate (in industry, raw gas) 7% 20%
Coal, fluidized (in industry, raw gas) 5% 26%

Brown coal, pulverized (in industry, raw
10% 35%
gas)
Hard coal, pulverized (in industry, raw
6% 23%
gas)
Derived coal (in industry, raw gas) 45% 79%
Biomass (in industry, raw gas) 77% 89%
Waste (in industry, raw gas) 23% 38%
Coal, grate (in power plants, raw gas) 14% 37%
Coal, fluidized (in power plants, raw gas) 5% 26%

Brown coal, pulverized (in power plants,
10% 35%
raw gas)
Hard coal, pulverized (in power plants,
6% 23%
raw gas)
Hard coal, wet bottom (in power plants,
21% 23%
raw gas)
Derived coal (in power plants, raw gas) 45% 79%
Biomass (in power plants, raw gas) 77% 89%
Waste (in power plants, raw gas) 23% 38%
Coal, stoves and boilers (domestic) 13% 90%
Coal, large boilers (residential) 7% 20%
Derived coal (residential) 45% 79%
Biomass, stoves and boilers (domestic) 93% 96%
Biomass, large boilers (residential) 77% 89%
Waste (residential) 60% 90%
Fireplaces, stoves (wood burning in DOM_FPLACE,

kt/PJ 0,279 93% 0,288 96% 0,3
Eastern Europe) DOM_STOVE
Small domestic boilers (wood burning in DOM_SHB_M, 37% - 0,096 - 37% - 0,1 -
kt/PJ 0,093 - 0,23
Eastern Europe) DOM_SHB_A 92% 0,24 96% 0,25
Large residential boilers (wood burning in DOM_MB_M, 39% - 0,089 - 45% -

kt/PJ 0,077 - 0,15 0,1 - 0,2
Eastern Europe) DOM_MB_A 75% 0,18 90%
Industry (wood burning in Eastern PP_, IN_,

kt/PJ 0,185 77% 0,214 89% 0,24
Europe) CONV_COMB
Fireplaces, stoves (wood burning in DOM_FPLACE, 34% - 0,07 - 35% - 0,072 -

kt/PJ 0,067 - 0,186
Western Europe) DOM_STOVE 93% 0,192 96% 0,2
Small domestic boilers (wood burning in DOM_SHB_M, 33% - 0,062 - 34% - 0,065 -
kt/PJ 0,06 - 0,167
Western Europe) DOM_SHB_A 93% 0,17 94% 0,18
Large residential boilers (wood burning in DOM_MB_M, 33% - 0,06 - 40% - 0,065 -
kt/PJ 0,05 - 0,12
Western Europe) DOM_MB_A 80% 0,134 89% 0,15
Industry (wood burning in Western PP_, IN_,

kt/PJ 0,185 77% 0,214 89% 0,24
Europe) CONV_COMB

Table 7: shares of PM2.5 and PM10 in TSP as used in RAINS (2002) [15]
%
Sector Name RAINS-Code(s) Unit PM2.5 PM10 %PM10 TSP
PM2.5
Power plants (stationary combustion of PP_NEW, Mis en forme : Gauche
kt/PJ 0,0093 60% 0,0132 85% 0,0155
heavy fuel oil) PP_EX
Conversion (stationary combustion of Mis en forme : Gauche
CON_COMB kt/PJ 0,0117 60% 0,0166 85% 0,0195
heavy fuel oil)
Industry (stationary combustion of heavy Mis en forme : Gauche
IN_BO, IN_OC kt/PJ 0,0104 60% 0,0147 85% 0,0173
fuel oil)
Residential (stationary combustion of Mis en forme : Gauche
DOM kt/PJ 0,0095 25% 0,0247 65% 0,038
heavy fuel oil)
Power plants (stationary combustion of Mis en forme : Gauche
PP_NEW kt/PJ 0,0004 18% 0,0011 50% 0,0022
light fuel oil), new
Power plants (stationary combustion of Mis en forme : Gauche
PP_EX kt/PJ 0,0007 19% 0,0018 50% 0,0036
light fuel oil), existing
CON_COMB kt/PJ 0,0004 11% 0,0018 50% 0,0036
light fuel oil)
Industry (stationary combustion of light Mis en forme : Gauche
IN_BO, IN_OC kt/PJ 0,0003 14% 0,0011 50% 0,0022
fuel oil)
Residential (stationary combustion of Mis en forme : Gauche
DOM kt/PJ 0,0007 41% 0,0009 53% 0,0017
light fuel oil)
Power plants (stationary combustion of PP_NEW, Mis en forme : Gauche
kt/PJ 0,0001 100% 0,0001 100% 0,0001
natural gas) PP_EX
CON_COMB kt/PJ 0,0001 100% 0,0001 100% 0,0001
natural gas)
Industry (stationary combustion of Mis en forme : Gauche
IN_BO, IN_OC kt/PJ 0,0001 100% 0,0001 100% 0,0001
natural gas)
0,0000
Residential (stationary combustion of 0,00003 - 0,00003 Mis en forme : Gauche
DOM kt/PJ 100% 3- 100%
natural gas) 0,0002 - 0,0002
0,0002
Coke Production PR_COKE kt/ton 1,9971 40% 3,3618 68% 4,976
Sinter processes PR_SINT kg/ton sinter 0,557 7% 1,285 15% 8,563
Sinter fugitive PR_SINT_F kg/ton sinter 0,104 7% 0,24 15% 1,6
Pellet plant PR_PELL kg/ton pellet 0,03 100% 0,03 100% 0,03
Pig iron production PR_PIGI kg/ton pig iron 0,15 10% 0,24 16% 1,48
Pig iron production (fugitive) PR_PIGI_F kg/ton pig iron 0,15 6% 0,25 10% 2,5
Open-hearth furnace PR_HEARTH kg/ton steel 6,33 60% 8,76 83% 10,55
Basic oxygen furnace PR_BAOX kg/ton steel 10,45 50% 14,63 70% 20,9
Electric arc furnace PR_EARC kg/ton steel 7,55 43% 10,18 58% 17,55
Iron foundries PR_CAST kg/ton iron 10,68 71% 13,55 90% 15,05
Iron foundries (fugitive) PR_CAST_F kg/ton iron 1,38 24% 2,82 49% 5,75
Aluminium production (primary) PR_ALPRIM kg/ton aluminium 18,5 39% 27,26 58% 47
Aluminium production (secondary) PR_ALSEC kg/ton aluminium 5,195 44% 6,93 58% 11,9
Other Non-ferrous metals PR_OT_NFME kg/ton metal 12,3 82% 13,8 92% 15
Cement production PR_CEM kg/t cement 23,4 18% 54,6 42% 130
Lime production PR_LIME kg/t lime 1,4 1% 12 12% 100
Petroleum refining (refineries) PR_REF kg/t crude oil 0,096 79% 0,12 98% 0,122
Fertilizer production PR_FERT kg/t 18 36% 30 60% 50
Carbon Black production PR_CBLACK kg/t 1,44 81% 1,6 90% 1,78
Glass production PR_GLASS kg/t glass 2,96 91% 3,09 95% 3,25
Other production (PVC, gypsum, glass 3% - 11% - Mis en forme : Gauche
PR_OTHER kg/ton product 0,5 - 8 2 - 15 5 - 17,5
fibre) 46% 86%

Major stationary sources of dust emissions are therefore combustion processes, in particular of coal,
fuel oil and biomass but also of black liquor in paper industry, industrial processes like sintering,
cement production etc. as well as storage, handling and mechanical processing of materials.
BC emission inventories are available at the global scale or local level. Reference [21] provides an
overview of available inventories [22], [23], [24], [25] at the global scale. The GAINS model has been
extended to cover BC and OC [27]. A report on emission factor determination is available from IIASA
[26]. Uncertainties are still considerable regarding sources such as combustion, agricultural burning,
and open biomass burning (wild fire and prescribed forest burning), however there is a consensus on
the most important sources of BC. These sources are [17], [19]:
In UNECE regions:
the on-road and off-road diesel engines including marine engines;
the domestic sector due to emissions from domestic heating, primarily wood but also coal
combustion;
the open biomass burning sector, primarily due to emissions from agricultural burning,
prescribed burning in forestry, and wildfires.
Globally, important sources include residential cook stoves in all regions; brick kilns and coke ovens in
Asia; and mobile diesel vehicles and marine engines in all regions; open biomass burning in all
regions. Gas flaring from fossil fuel extraction is also considered as a significant BC emission source
by most publications.
The following graph presents emission sources in the UNECE region according to GAINS [28]. In this
region, residential combustion (biomass and coal), road traffic and off-road machineries are the largest
sources of BC. Off-road sources are very significant as well as open biomass burning in agricultural
activities.
Figure 1: BC and OC emission sources in the UNECE region according to GAINS [28]
SNAP 1: combustion in energy and transformation industries

SNAP 2: non industrial combustion plants
SNAP 3: combustion in manufacturing industries
SNAP 4: production processes
SNAP 5: extraction and distribution of fossil fuels and geothermal energy
SNAP 6: solvent and other product use
SNAP 7: road transport
SNAP 8: other mobile sources and machinery
SNAP 9: waste treatment and disposal
SNAP 10: agriculture
In order to reduce dust formation and dust emissions different types of measures like energy efficiency
improvements (cf. Chapter 2.2), fuel switching, fuel cleaning, better handling of materials as well as

abatement measures are applied. To achieve the most efficient dust reduction, beyond energy
management measures, a combination of measures should be considered. To identify the best
combination of measures a site-specific evaluation is needed.
6.2 Fuel switching

Fuel switching is an important option to reduce dust emissions from combustion but is governed by
country specific conditions such as infrastructure and energy policy. Dust emissions are in general
lower if the fuel allows a more homogenous combustion, contains less sulphur and less ash but more
hydrogen. Therefore, combustion of natural gas is in general associated with low emissions whereas
high dust emissions result from combustion of fuel oil, biomass and coal if no abatement measures
are applied.
BC mainly results from incomplete combustion. The form of the fuel influences the likelihood of
complete combustion and the reduction of BC can be achieved through fuels able to limit the
occurrence of incomplete combustion [19]:
Gas phase fuels (e.g., natural gas) can be readily mixed with oxygen, which reduces the emission of
carbonaceous particles.
Liquid fuels (e.g., gasoline) generally must vaporize in order to fuel flaming combustion. If a liquid fuel
contains heavy oils, vaporisation and thorough mixing with oxygen are difficult to achieve.
Solid fuels (e.g., wood) require preheating and then ignition before flaming combustion can occur.
High fuel moisture can suppress full flaming combustion, contributing to the formation of Brown
Carbon (Bra) particles as well as BC.
The choice of the fuel may also have effects on other emissions like sulphur, NOx and greenhouse
gas emissions as well as on applicability and need of abatement measures.
6.3 Fuel cleaning

Fuel cleaning is important for coal and fuel oil.
Conventional coal cleaning techniques rely on gravity-based separation of ash and sulphur
compounds using jigs, dense-medium baths, cyclones or flotation of grinded coal. While 60 to 90%
and 85 to 98% of the heating value of the coal is retained, ash removal can reach 60% and total
sulphur removal 10 to 40%. Both sulphur and ash removal contributes to a reduction of dust
emissions. Sulphur removal increases with the content of pyritic sulphur in the coal [4]. Advanced
techniques are mostly based on:
advanced physical cleaning (advanced froth floatation, electrostatic, heavy liquid cycloning),
aqueous phase pre-treatment (bioprocessing, hydrothermal, ion exchange),
selective agglomeration (Otisca, LICADO, spherical agglomeration Aglofloat),
organic phase pre-treatment (depolymerisation, alkylation, solvent swelling, catalyst addition
(e.g., carbonyl), organic sulphur removal).
These advanced coal cleaning techniques are still in development or demonstration phase [4].
Besides a reduction of sulphur and dust emissions, reported advantages are lower transportation
costs if coal is cleaned already at the mine, higher boiler availability, less boiler slagging and fouling,
less wear on equipment, lower dust load. Disadvantages are energy loss from cleaning (2-15%),
energy costs for the processes and an increased moisture content of the coal if water-based
processes are used [4].
Fuel desulphurisation for fuel oil is common practice in order to achieve low sulphur fuels which are
e.g. required in the EU by Directive 1999/32/EC (heavy and light fuel oil less than 1% resp. 0.1% wt).
Removing of sulphur reduces sulphur based dust emissions (Chapter 3.4 describes the
desulphurisation processes of fuel oils).

6.4 Primary measures

Unloading, handling and storage of solids
During unloading, storage and handling, e.g. loading, of solids dust emissions might occur. In general
particle size of dust from unloading, storage and handling of solid is larger than dust from e.g.
combustion. The use of enclosed or housed systems, e.g. covered continuous conveying systems,
and reducing of drop heights may reduce dust emissions from unloading and handling [3]. Approaches
to minimise dust from storage can be differentiated into primary measures which reduce emissions
and secondary measures which aim at limiting the distribution of the dust [2]. Primary measures can
be further differentiated into organisational, constructional, and technical measures. Technical primary
measures are wind protection, covering or avoidance of open storage, and moistening of the open
storage, e.g. by a sprinkler systems. Secondary measures are spraying, water curtains and jet
spraying as well as installation of filters in e.g. silos [2]. Spraying water is also a measure to reduce
dust emissions from construction sites.
Capture of emissions
A prerequisite for later dust abatement is the capture of fugitive dust emissions, e.g. in the iron and
steel industry, and venting to dust control systems.
Combustion technique and optimisation

A smooth, continuous and complete combustion generates less dust (including PM10, PM2.5 and black
carbon) emissions. An optimised air supply, mixing of fuel and air as well as burner/boiler design
reduce the formation of soot and other substances resulting from incomplete combustion such as BC.
Therefore good housekeeping of boilers as well as the use of new, more efficient boilers and stoves,
especially in the residential and commercial sector, may reduce dust and BC emissions. In this way
dust and BC emissions from wood and coal stoves can be considerably reduced. Changing from batch
to continuous operation of boilers allows for a better combustion control and reduces dust and BC
emissions. Primary measures for NOx reduction may, however, increase soot formation (cf. Chapter 4)
A lowering of the combustion temperature reduces ash volatisation. Fuel additives and sorbents are
proposed to reduce the formation of fine particles and metals in the fine particles. In Integrated
gasification combined cycle (IGCC) the fuel is gasified under reducing conditions to syngas. The
syngas is then cleaned and burnt in either air or oxygen. This allows the achievement of very low dust
emission levels. IGCC is seen as one of several key technologies in the framework of carbon capture
and storage (CCS). So far its application is restricted to few, mostly demonstration plants. With CCS-
IGCC could become commercially available around 2020 [5].
6.5 Secondary measures

Secondary measures (add-on or end of pipe technologies) reduce the emissions of PM which is
already in the flue gas. Several main principles are used for secondary measures:
inertia of particles,
sieving and adsorption,
electrostatic charging of particles and subsequent precipitation making use of an electric field,
scrubbing.
1
The following secondary measures are mainly in use, each with its specific advantages and
disadvantages according to the size of particles. Because BC from incomplete combustion is mainly
associated to particles with a diameter less than 1 µm, only reduction techniques able to remove fine
particles will have a significant efficiency on BC emissions:
gravity settling chamber: In gravity settling chambers the flow rate of the air is reduced so that
larger particles sink and settle. Gravity settling chambers are only useful for removing the
largest particles in terms of "pre-cleaning". The minimum particle size removed by gravity
settling chambers is >20 µm [1].Table 8 presents dust removal efficiencies of gravity settling
chamber. This equipment is not suitable for removal of fine particle and BC.
Mis en forme : Police :(Par défaut)
1
The performance data in the following paragraphs mainly refer to boiler installations Arial, 9 pt

cyclone: In cyclones inertia of particles are used for dust removal. In a cyclone the flue gas is
forced (usually via a conical shaped chamber) into a circular motion where particles are forced
by inertia to the cyclone walls where they are collected. Collection efficiency depends strongly
on particle size and increases with the pollutant loading. For conventional single cyclones it is
estimated to be 70-90% for TSP, 30-90% for PM10 and 0-40% for PM2.5 [6]. The minimum
particle size removed by cyclones is 5-25 µm and 5 µm in multicyclones [1]. Conventional
cyclones are therefore referred to as "pre-cleaners". Conventional cyclones alone are not BAT
for industrial installations but could be an option to reduce dust emissions from small
combustion installations, e.g. in households or in the commercial sector. High efficiency
cyclones removing 60-95% of PM10 and 20-70% of PM2.5 have been developed but at the
expense of a high pressure drop leading to high energy and hence operation costs [6].
Achieving higher removal efficiencies in cyclones is mainly a problem of the resulting pressure
drop. High throughput cyclones have been designed on purpose for removing just the larger
dust fraction at the expense of only low pressure drop. In multicyclones many small cyclones
operate in parallel achieving removal efficiencies similar or superior to high efficiency cyclones
(cf. [6]). Application of cyclones as a pre-cleaner to remove abrasive particles may increase the
lifetime of other abatement equipment. Cyclones are also used to recover recycling products,
process materials etc. from the flue gas, e.g. in the ferrous and non-ferrous metals industry.
Advantages of cyclones are: low investments, low operating and maintenance costs relative to
the amount of PM removed, temperature and pressure range only limited by material, collection
of dry material, relatively small in size. Disadvantages include low removal efficiencies for fine
PM (or alternatively high pressure drops) and non-applicability for sticky materials. The
efficiency of cyclones on BC can be assumed similar to the efficiency obtained on PM 2.5,
electrostatic precipitator (ESP): The principle behind ESP is that particles of the flue gas
stream are electrostatically charged when passing through a region with gaseous ions (corona)
generated by electrodes at high voltage (around 20 to 100 kV). The charged particles are then
redirected in an electric field and settle at the collector walls. As large particles absorb more
ions than smaller ones, ESP removal efficiency is higher for larger particles. New ESP typically
may achieve PM removal efficiencies of 99% to about 99.99% if perfectly dimensioned and in
optimal operation conditions, in the range 0.01 to >100 µm, older ones 90 to 99.9% [1], [7], [8].
The minimum particle size removed by ESP is <1 µm [1]. Removal efficiencies are lowest for
particles with a diameter of 0.1 to 1 µm. Efficiency depends on the ESP size (collection area)
but also on dust resistivity, temperature, chemical composition of the dust and gas and particle
size distribution. The electrical conductivity of dust is one of the most relevant properties for
ESP operation. In good and steady combustion conditions, particles are mainly composed of
inorganic compounds such as salts which present ideal conductivity and are removed efficiently
with the ESP. Soot and BC reveal high conductivity thus enabling high precipitation efficiency
but severe re-entrainment of agglomerated particles. Condensable organic compounds (COC)
from wood combustion (which are formed at low temperature from wood pyrolysis with
characteristic compounds depending on residence time, heating rate, temperature and other
operation parameters and at moderate temperatures and local lack of oxygen) exhibit low
conductivity thus leading to back-corona which limits ESP operation [29], [30].
Dust at the collectors can be removed either dry or wet by a spray of usually water (dry or wet
ESP). Dry ESPs are more common as dry collected dust is easier to handle than slurry which
requires after treatment. Wet ESPs need noncorrosive materials. However, removal of particles
with extremely low or high resistivity is difficult in dry ESPs whereas wet ESPs can also collect
particles with high resistivity as well as sticky particles, mists or explosive dusts. Wet ESPs
show also higher efficiencies for smaller particles. Injection of conditioning gases, liquids or
solids, in particular water and SO 3, may improve removal efficiencies [1]. Advantages of ESPs
are in general very low pressure drops, very good removal efficiencies (but less pronounced for
fine particles), low operating costs as well as wide applicability (sticky, glowing, high resistivity
(wet ESP) particles, mists, acids, ammonia, exploding gases (wet ESP)) [1], [7], [8].
Disadvantages are high investments, high space demand, ozone formation due to high voltage,
need for specialised personnel for high voltage, and limited applicability in case of varying flue
gas conditions (flow rate, temperature, dust load, composition of dust) as well as necessary
after treatment of slurry (wet ESPs), but almost closed water loops are achievable [1], [7], [8].
For combustion installations, ESPs can guarantee low dust and BC emissions when stable and
good combustion conditions are achieved. On contrary, during transient conditions, dust
(including PM10, PM2.5 and black carbon) emissions can be increased not only due to increased

raw gas concentrations, but additionally due to reduced precipitation efficiency. All measures to
insure steady state running of combustion installations are unavoidable even if an ESP is
present (refer to chapter 6.4 for optimisation of the combustion).
To achieve high efficiency of dust and BC removal with ESP, the following recommendations
are provided by references [29], [30] for biomass combustion:
1. Optimum design and system integration of combustion and ESP enabling steady operation,
2. Process integrated control of ESP with specific information as indicators for the particle
properties: flue gas temperature (as often carried our presently), excess air ratio, combustion
temperature, water content of the fuel. This increases the range of conditions when the ESP is
effective.
3. Measures to avoid re-entrainment: limitation of gas velocity to < 1.5 m/s, optimised shape of
collecting plates, shorter dedusting interval during re-entrainment regimes.
The lower efficiency of ESPs on sub micrometer particles can be addressed by the use of an
association of an ESP and a FF or the use of an agglomerator (see here after). These two
techniques have been defined as emerging techniques by EGTEI [31].
fabric filter (FF): In a FF the flue gasses pass through a permeable fabric where larger
particles are sieved or adsorbed. The filter cake made up of collected particles supports the
collection of further particles. As pressure drop increases with filter cake thickness the fabric
filter needs to be cleaned from time to time. Three main cleaning mechanisms are applied:
pulse jet filters where filters are cleaned by a pulse of pressurized air from the other side,
shaker mechanisms and reverse gas flow. Pulse jet filters are today the most common type as
they demand less space, are less expensive and applicable for high dust loadings and cause
constant pressure drop [1], [9], [10]. Removal efficiencies are 99 to 99.99% for new and 95 to
99.9% for older installations [1], [9], [10] and depend on filtration velocity, particle and fabrics
characteristics and applied cleaning mechanism. FF is in particular able to remove fine and
ultrafine dust and is consequently efficient to remove BC. Flue gas conditioning using mainly
elemental sulphur, ammonia and SO 3 is applied to achieve higher removal rates, reduce
pressure drop, and reduce re-entrainment of particles [1]. New developments are the addition of
activated carbon or lime to achieve reactions in the filter cake as well as a catalytic filter material
[1]. Flue gas temperature depends on the filter material used and the dew point of the flue gas
and is in general between 120-180°C [1]. Advantages of FF are very low emission levels even
down to ultrafine particles (depending on fabric) and achieved independent from dust loading,
flow rate (e.g. start-ups) and dust type (. (except COC due to their sticky properties [30]),
simple operation and in general no corrosion problems. Disadvantages are relatively high
maintenance and operating costs due to replacement of filter bags (lifetime depends on
temperature and dust) and pressure drop and in particular limitations in applicability in moist
environments and for hygroscopic, glowing and sticky particles as well as for acids and
ammonia and exploding gases [1], [9], [10]. Large particles need to be removed in advance [1].
Bypassing is necessary during failure.
wet scrubber: Injecting water into the flue gas stream leads to formation of water droplets
which with dust, forms a slurry. Scrubbers are mainly used for SOx removal but reduce also
dust. Removal efficiencies are up to 80% for spray towers as well as dynamic and collision
scrubbers and up to 99 % for venturi scrubbers [1]. The minimum particle size removed by
spray towers is >10 µm, by dynamic and collision scrubbers > 2.5 µm and by venturi scrubbers
>0.5 µm. Advantages of wet scrubbers are simultaneous removal of SOx and dust (and even
other pollutants like HCl and HF), low maintenance, rather high removal e fficiencies (in
particular venturi scrubbers), few application limits (flow rate fluctuations, hot or cold, wet and
corrosive gases, mists are uncritical) and reduced explosion risks from dust. Disadvantages are
waste generation (slurry), high maintenance costs due to potentially high pressure drop,
corrosion problems and rather low removal efficiency for very fine particles such as those to
which BC is associated [1].
oxidation techniques (described in chapter 5.3.2) used to abate VOC, PAH and odours can
also be a useful technique to break down organic matter, including BC in some specific
applications. Organic matter like BC can be incinerated indeed. This oxidation takes place in a
thermal oxidation step in an off-gas burner, or in a catalytic oxidation installation. Oxidation
techniques are used to abate anode plant emissions which partially consist of pitch and tar
fumes and are rich in PAHs. Oxidation techniques abate pitch and tar fumes as well as
condensed and volatile PAHs as well [32], [33].

promising emerging dust control techniques include [31]:

- COHPAC and TOXECON technologies: COHPAC (Compact Hybrid Particulate
Collector) and TOXECON are multi multi-pollutant control technologies for mercury, dioxins
but also other pollutants including fine particles developed and applied in the U.S.A. In
COHPAC a FF is installed downstream of an existing ESP. As the ESP removes most of the
dust, the filtration rate of the FF can be increased substantially while keeping a modest pressure
drop [11]. ESP might also lead to agglomeration of very fine particles which can be then
removed in the FF. TOXECON refers to the injection of a dry sorbent like activated carbon
between the ESP and FF.
- indigo Agglomerator: The Indigo Agglomerator forms large agglomerated particles by
attaching fine particles to larger particles. The agglomerated particles can be easily removed
using standard techniques like ESP. This technique allows also the reduction of mercury
emissions [12] and may be used in case of significant concentrations of BC associated to sub
micrometer particles [19].
To sum up, a variety of measures to reduce dust emissions exist. Some like cyclones are able to
reduce the large and to some extent also the coarse fraction but are considerably less efficient for the
fine fraction of dust. For fine and submicron dust fabric filters achieve very high removal efficiencies
(up to 99.99% and above). Highly efficient ESPs, in particular Wet ESPs, as well as Venturi scrubbers
may also achieve relatively high removal efficiencies for this size class up to 95% to 99%. Emerging
techniques like the Indigo Agglomerator might contribute to increase ESP efficiency for fine particles
by increasing the particle size.
However, when comparing removal efficiencies it need to be taken into account the characteristics of
the dust and the flue gas as well as other parameters like dust load, flow rate, fluctuations as these
factors may have a large impact on overall and size-specific removal performance. Furthermore
removal rates largely depend on the specific design of the dust collector, e.g. on chosen filter material
and ESP dimensioning, and in the end investment and operating costs.

Table 8: Removal efficiencies of dust abatement measures for different particles size for boiler
plants
Removal efficiencies [%]
submicron fine coarse large
Category Type Subtype <1 µm 0-2.5 µm 2.5-6 µm 6-10 µm 2.5-10 µm >10 µm
RAINS* US EPA** RAINS** US EPA** RAINS** RAINS**
high efficiency 3.6 5 6
Gravity Gravity collector medium efficieny 2.9 4 4.8
and low efficiency 1.5 3.2 3.7
centrifugal high efficiency 80 95 95
collector Centrifugal collector medium efficieny 50 75 85
low efficiency 10 35 50
Single cyclone 10 35 50
Multiple cyclone without fly ash
80 95 95
reinjection
Cyclone Multiple cyclone with fly ash
50 75 85
reinjection
Cyclone/Multcyclone unspecified 11 30 70 90
Wet cyclonic separator 50 75 85
ESP high efficiency 98.6 95 99 99 99.5 99.9 99.95
medium efficiency
ESP 95.4 96 99 99,9
(unspecified)
low efficiency
ESP 91.96 93 95 97
(unspecified)
ESP
wet ESP 98.86 99 99.9 99.95
medium efficieny 50 80 94
ESP: boilers
medium efficieny 80 90 97
ESP: other than boilers
high temperature 99 99.5 99.5
Fabric
Fabric filter medium temperature 99 99.5 99.5
Filter
low temperature 99.99 99 99 99.5 99.5 99.9 99.98
Spray tower 20 80 90
high efficiency 95 90 96 95 99 99 99.5
Scrubber Wet scrubber medium efficieny 25 85 95
Venturi scrubber 90 95 99
Process enclosed 1.5 3.2 3.7
Dust suppression by water sprays 40 65 90
Dust suppression by chemical
40 65 90
stabilizer or wetting agents
Other Water curtain 10 45 90
Good practice: industrial processes
stage 1 20 10 15 20
(fugitive)
Good practice: industrial processes
stage 2 65.33 30 50 75
(fugitive)
* Kupiainen, K. & Z. Klimont (2004) Primary emissions of submicron and carbonaceous particles in Europe and the potential for their control. - IIASA Interim Report IR-04-079, 122 pp.
** Klimont, Z. J. Cofala, I. Bertok, M. Amann, C. Heyes & F. Gyarfas (2002): Modelling Particulate Emissions in Europe. - IIASA Interim Report IR-02-076, 179 pp.
*** US EPA (1996): AP 42, Volume I, Fifth Edition, Appendix B.2 Generalized Particle Size Distributions
Because most BC is within the fine or submicron size categories, the removal efficiencies for fine and
especially submicron particles indicated in table 8 can be used as a rough proxy for BC removal
efficiencies.
The selection of the most suitable measure depends on many factors related to e.g.such as the
following ones:
flue gas characteristics (dust concentration and characteristics like particle size distribution,
resistivity, temperature, humidity, other pollutants present like acids, SOx, etc.),
flow rate and fluctuations of flue gas,
operation mode of installation,
process specifics in industrial processes,
new installation or retrofitting, e.g. available space,
emission levels to be achieved,
side and cross media effects,
operational safety and reliability,
site specifics,
costs.

6.6 Costs of dust emission reduction techniques

Costs are an important issue when selecting PM emission reduction techniques. The following
expenses may be relevant [13]:
labour costs,
energy costs,
often more cost-effective. Retrofitting of existing installations is often possible but in general at higher
costs.
For ESP investments are relatively high whereas maintenance and operating costs are relatively low,
in particular as a result of the low pressure drop. Other costs are related to personnel specialised for
high voltage and in case of wet ESP costs for slurry treatment.
For fabric filters, investments are lower but maintenance and operating costs are higher as fabrics
have to be changed regularly (depending on flue gas and dust characteristics) and as the pressure
drop is modest to high.
6.7 Side effects

accounted for. Side effects can generally be limited by properly designing and operating the facilities.
Side effects include:
impacts on the use of natural resources,
A core side effect of dust emission reduction is the simultaneous reduction of heavy metals (except for
mercury) [14]. Depending on its characteristics and chemical composition collected dust can be
recycled, e.g. in iron and steel industry, or has to be disposed.
More specifically, the side effects to be considered with different PM emission reduction techniques
are:
Electrostatic precipitator (ESP): For ESPs a main side effect is electricity consumption for producing
the corona and the electric field. However, as pressure drop is low in ESPs, overall electricity
consumption is considerably lower than in FF where high pressure drops have to be compensated for.
In wet ESPs treatment of the slurry is necessary but water recirculation reaches almost 100% so that
waste consumption is low. As ESPs have considerably lower removal efficiencies in the size range 0.1
to 1 µm removal of heavy metals in ESPs is far lower than in FF.
Fabric filters (FF): Fabrics have to be changed around every 2 to 4 years (lifetime depends on
various factors) so that waste is generated if reprocessing of the fabrics is not possible. The pressure
drop in FFs has to be compensated for by pumping leading to additional electricity consumption. As
FFs are also very effective in removal of fine particles, they also effectively reduce emissions of heavy
metals which are enriched in the sub-micrometer size range of dust in flue gases.


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emissions in energy generation and industry. Views and conclusions of the FINE Particles -
Technology, Environment and Health Technology Programme, VTT Technical Research Centre of
Finland.
[2] Storage BREF (2006): Reference Document on Best Available Techniques for Emissions from
Storage. – European Commission, 460 pp.
[4] Worldbank: Coal Cleaning, http://www.worldbank.org/html/fpd/em/power/EA/mitigatn/aqsocc.stm,
accessed 27.09.2008.
[5] Results of work of the EGTEI expert sub-group on Emerging Technologies/Techniques. Report by
the Chair of the Expert sub-group on Emerging Technologies/Techniques to the Working Group on
Strategies and Review – 1 – 5 September 2008.
[6] US EPA: EPA-CICA Air Pollution Technology Fact Sheet "Cyclones".
[7] US EPA: EPA-CICA Air Pollution Technology Fact Sheet "Wet Electrostatic Precipitator (ESP) -
Wire-Pipe Type".
[8] US EPA: EPA-CICA Air Pollution Technology Fact Sheet "Dry Electrostatic Precipitator (ESP) -
Wire-Plate Type".
[9] US EPA: EPA-CICA Air Pollution Technology Fact Sheet "Fabric Filter, Pulse-Jet Cleaned Type".
[10] US EPA: EPA-CICA Air Pollution Technology Fact Sheet "Fabric Filter, Mechanical Shaker
Cleaned Type".
[11] Miller, R., R. Chang & C.J. Bustard (2003): Effective use of both COHPACT and TOXECON
technologies as the "Technology of the future" for particulate and mercury control on coal -fired boilers.
- Text prepared for 2003 International Power-Gen Conference, Las Vegas, U.S.A.
[12] Truce, R. (2008): Enhanced fine particle and mercury emission control using the Indigo
Agglomerator. - VGB powertech 88, 95-101.
[13] VDI 3800, Determination of costs for industrial environmental protection measures. Verein
Deutscher Ingenieure, 2001.
[14] Kraus, K., S. Wenzel, G. Howland, U. Kutschera, S. Hlawiczka, A. P. Weem and C. French
(2006): Assessment of technological developments: Best available techniques (BAT) and limit values.
Submitted to the Task Force on Heavy Metals, UNECE Convention on Long-range Transboundary Air
Pollution.
[15] GAINS Europe - http://gains.iiasa.ac.at/index.php/gains-europe
[16] UNECE - Ad Hoc Expert Group on Black Carbon - Black carbon - Report by the Co-Chairs of the
Ad Hoc Expert Group on Black Carbon. Executive Body for the Convention on Long-range
Transboundary Air Pollution. Twenty-eighth session Geneva, 13–17 December 2010.
[17] Arctic Council - Task Force on Short-Lived Climate Forcers - “An Assessment of Emissions and
Mitigation Options for Black Carbon” – 2011.
[18] UNEP/WMO - Integrated Assessment of Black Carbon and Tropospheric Ozone – 2011.
[19] United States Enviromental Protection Agency – Report to congress on Black carbon USA March
2012.
[20] Kupiainen, K. & Klimont, Z., 2007. Primary Emissions of fine carbonaceous particles in Europe
Atmospheric environment – 41 – (2007) - 2156-2170.
[21] H-C Hansson and alls, Stockholm University and Karin Kindbom and alls, IVL Swedish
Environmental Research Institute - Black carbon – Possibilities to reduce emissions and potential
effects. July 2011.
[22] Visschedijk, A.J.H., Dernier van der Gon, H.A.C., Dröge, R., Van der Brugh, H., 2009. A
European high-resolution and size-differentiated emission inventory for elemental and organic carbon
for the year 2005. TNO report TNO-034-UT-2009-00688_RPT-ML. PO Box 80015, 3508 TA Utrecht,
The Netherlands.

[23] Van der Gon H., Visschedijk A., Kuenen J, Harrison R., Beddows D., Prior S., Sørensen
L.L.,Janhäll S., Pandis S., Johansson C., Hedberg Larsson E., De Leeuw G., and O‘Dowd C. Progress
in Eucaari Wp 1.3: Anthropogenic and Biogenic Emissions of Aerosols and Precursors. In
Proceedings of 2007 EUCAARI Annual Meeting Helsinki 20.-22.11.2007, Kulmala et al. (Eds.), Report
Series in Aerosol Science, 91. http://www.atm.helsinki.fi/~asmi/EUCAARI/EUCAARI_rs91.pdf.
[24] Bond, T.C., Streets, D.G., Yarber, K.F., Nelson, S.M., Woo, J.-H., Klimont, Z., 2004. A
technology-based global inventory of black and organic carbon emissions from combustion. Journal of
Geophysical Research 109, D14203.
[25] Junker, C and Liousse, C., 2008. A global emission inventory of carbonaceous aerosol from
historic records of fossil fuel and biofuel consumption for the period 1860 –1997. Atmos. Chem. Phys.,
8, 1195–1207.
[26] Kupiainen, K. & Klimont, Z., 2004. Primary Emissions of Submicron and Carbona ceous Particles
in Europe and the Potential for their Control. International Institute for Applied Systems Analysis
(IASA), Interim report IR-04-79, Schlossplatz 1 A-2361 Laxenburg Austria.
[27] Amann, M. - 2008, The Greenhouse Gas – Air Pollution Interactions and Synergies Model
(GAINS). Interim Report on Modelling Technology, European Consortium for Modelling of Air Pollution
and Climate Strategies - EC4MACS. Task 2: Integrated Assessment of Air Pollution and Greenhouse
Gases.
[28] Klimont, Z. - Center for Integrated Assessment Modelling (CIAM) - International Institute for
Applied Systems Analysis (IIASA).
Current Emissions and Baseline Projections of Black Carbon in UNECE area GAINS model – working
progress. UNECE TFEIP Stockholm, May 2-3, 2011.
[29] Nussbaumer,T. & Lauber, A. - Formation mechanisms and physical properties of particles from
wood combustion for design and operation of electrostatic precipitators - 18th European Biomass
Conference and Exhibition, Lyon, 3–7 May 2010, OA11.3, ETA-Florence 2010.[30] Nussbaumer, T. -
Overview on Technologies for Biomass Combustion and Emission levels of Particulate Matter,
prepared for the Swiss Federal Office for the Environment and EGTEI, 2010.
[31] EGTEI - Expert sub-group on Emerging Technologies/Techniques on Large Combustion Plants
>500 MWth up to 2030 – 2008.
[32] Information from A. Peeters Weem, INFO MIL Netherlands in the scope of the review of the
guidance document for inclusion of information on black carbon emission reduction techniques - June
2012.
th
[33] Mannweiler U. And alls - An anode plant in urban area: fiction or reality? - 12 Arabal, April 2 to
5, 2006.
[34] CIMAC document at
http://www.cimac.com/cimac_cms/uploads/explorer/Working%20groups/black_carbon.pdf
Mis en forme : Français (France)

7 Available techniques for different activities

Voluntary left blankVoluntary left blank

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including PM10, PM2.5
7.1 Combustion installations < 1 MW with domestic combustion

installations included
7.1.1 Coverage
Domestic combustion can be a significant source of NO X, SO2, VOCs and dust emissions (including
PM10, PM2.5 and black carbon (BC)) depending on the type of fuel used. This chapter covers domestic
appliances used for home heating and sanitary water heating. It covers installations with a thermal
input < 1 MW.
7.1.2 Combustion technologies

Domestic combustion appliances can be fed with different fuels, such as: natural gas, fuel oil, wood
and coal. A combination of different technologies of burners and different technologies of boilers can
be used in these appliances. For wood and coal use, stoves, inserts and open fire places can be used
as domestic appliances, as well as manually and automatically fuelled boilers.
7.1.2.1 Burner technologies
Gaseous fuels
Gaseous fuel burners are atomizing burners. Atomization increases the surface contact between air
combustion and fuel; it thus improves the combustion process. Atmospheric burners are used as well
as forced air burners.
Gaseous fuel burners can have different operating modes: on-off, 2 loads, modulating load.
On-off burners operate at nominal load.
2 load burners operate at nominal load or 40 – 60 % load depending on the demand.
Graduated load burners operate gradually depending on the demand, with a minimum of 30% load.
This last operating mode permits a better management of the fuel consumption. Hence, emissions are
reduced, especially start-up and shut-down-emissions.[1][1] Code de champ modifié
Different technologies of gaseous fuel burners can be used in domestic appliances. Mis en forme : Anglais (Royaume-Uni)
Low NOx burners limit the formation of NOx emissions. One of the techniques used consists in
recycling combustion flue gases into the burner air inlet. This reduces flame temperature, the oxygen
concentration and thus enables the reduction of NO x emissions.
Premixing type burners mix gaseous fuel and air inside a premixing chamber. The mix is then
distributed on a specific surface where the flame is developing. Different design of surface can be
used. This technique enables control and optimisation of the mixing. It is based on a modular air/fuel
ratio. It avoids air excess during the combustion and thus NO x emissions. This technique can be used
with catalytic combustion.
Radiating burners are only used with gaseous fuel. This technique permits flame temperature
reduction and thus limits NOx emissions during the combustion.
Liquid fuels
Liquid fuel burners are mostly atomizing burners and have the same operating modes as gaseous
fuel burners: on-off; 2 loads; modulating load.
Different technologies of liquid fuel burners can be used in domestic appliances.
Vaporizing burners are burners where liquid fuel is atomized under gaseous form. It enables a more
complete combustion and thus limits pollutant emissions but it is rarely used in boilers.
Low NOx burners are also used for liquid fuel, based on similar techniques as for gaseous fuel.

Biomass fuels
For wood combustion, burners are essentially used for pellets combustion in boilers or stoves.
Pellets are automatically supplied to the burner with a screw conveyor.
7.1.2.2 Boiler technologies used with gaseous and liquid fuels

A liquid or gas boiler generally consists of a burner, a combustion chamber and a heat exchanger. It
is equipped with a stack.
Burner burns fuel in the combustion chamber where combustion gases heat water in the heat
exchanger before exiting through the stack. The heated water can be used for home heating and/or
sanitary water.
Different types of boilers technologies can be used.
In low temperature boilers, burners are not operating at nominal load and water is heated at lower
temperatures (25-75°C instead of 70-80°C). Fuel consumption reductions of 12 to 15 % can be
expected in using this technology compared to the use of traditional technologies.[1][1] Mis en forme : Anglais (Royaume-Uni)
Condensing technology is used with gaseous fuel and, increasingly, with liquid fuels. It consists in Code de champ modifié
recovering the latent heat from water contained in the flue gas.
In using the heat exchanger with water at low temperature, the latent heat of the combustion gases
can be recovered. Combustion gases are condensed during the heat exchange. Thus, in using
condensing technology, more heat is recovered with less energy spent than using traditional
technology.
Boiler yield can be increased by 15 to 20 % using this technology compared to the use of recent
standard boilers.[1][1] Mis en forme : Anglais (Royaume-Uni)
The firm Ökofen uses condensing technology in one of its models to diffuse the emitted dust in the Code de champ modifié
condensed water contained in combustion gases. The advantage of this technique is both Mis en forme : Surlignage
improvement of energy efficiency and reduction of dust emissions (-10%). However, atmospheric dust
emissions avoided are contained in condensates. [8] Mis en forme : Surlignage
Flue gases from liquid fuel combustion contain less water to be condensed. Hence, condensing boiler
is less used for liquid fuels.
Condensing boilers are generally associated with low NOx burners.
Micro combustion technology is composed of an immersed combustion chamber, and a multitubular

heat exchanger. The combustion happens under the form of micro combustions (115 per second).
This technology enables to recover the latent heat from water contained in the flue gas like
condensing technology.
While condensing technology can be used with different type of fuel, micro combustion technology can
only be used with gaseous fuel.[5][5] Mis en forme : Anglais (Royaume-Uni)
Code de champ modifié
7.1.2.3 Technologies used with biomass fuels
Boilers
There are different types of wood boilers; mainly log boilers and pellet boilers.
Wood chip boilers can be used but are mainly used in larger installations (thermal output >30 kW).
The same technology is employed for pellet and wood chip boilers: fuel is automatically burnt by a
burner and the flue gases heat a calorific fluid (generally water) in a heat exchanger.
For log wood boilers, logs are loaded on a grate and are burnt using different technologies: vertical,
horizontal or inverted combustion and natural or forced draft.
For natural draft, three combustion techniques are used:

vertical combustion: all the wood logs loaded on the grate catch fire at the same time. This type
of combustion is very difficult to control; hence emissions are high and energy efficiency is low
(10-20%).
horizontal combustion: wood logs don’t catch fire at the same time. Wood logs are first dried
and then burnt. Flames are horizontal. This type of combustion is easier to control than
horizontal combustion and thus performances are higher.
inverted combustion: as in horizontal combustion, wood logs don’t catch fire at the same time
and are dried before being burnt. It is called inverted combustion because instead of going up
as in vertical combustion, flames are going down, through the grate. It is the best controlled
combustion type for natural draft; hence performances are the highest.
Forced draft boilers (also called “turbo” boilers) are more recent and have higher performances than
natural draft. Technique employed is the same as inverted combustion, but in “turbo” boilers,
introduction of combustion air is made by a fan and flue gases are sucked out. These types of boilers
apply staged combustion. Here primary air introduced on top of the fuel is involved in drying the wood
and in a gasification process which occurs in the first stage. In the second stage, gas combustion is
activated by the injection of secondary air. Staged combustion enables the good mixing of combustion
air with the fuel gases formed during the devolatilisation and gasification in the fuel bed [15]. The
control of combustion is improved thus enabling high efficiency and high temperature, key factors for a
complete combustion. and Tthese boilers have higher the highest performances.
In log wood boilers, a heat storage tank can be used to avoid part-load operating conditions. The
boiler can be operated at full load or at steady-state part-load which reduces emissions of combustion
residues. In manually or automatically operated boiler, a heat storage tank is advisable as it helps to
reduce part load emissions.
Low NOx technology as recycling of the combustion flue gases can also be applied to woo d boiler. Self
cleaning option is available for some boilers. It contributes to maintain appliances energy efficiency.
Other domestic appliances

Stoves, inserts and open fire places can be used for wood combustion:
open fireplaces are the worst technique: combustion is made in the ambient air. There is no
control of the combustion, energy efficiency is bad and emissions are high.
different technologies can be used in inserts: air regulation (air combustion can be heated
before to be injected in the combustion chamber), catalysis (a catalyst is added to drop
combustion temperature).
stoves: different technologies can be used.
 air regulation: air combustion can be heated before being injected in the combustion
chamber and it can be controlled automatically using an electronic device. This option
reduces real-life emissions.
 fuel used (pellets or wood logs) varies from a technology to another. Masonry stove can
accumulate energy during the combustion and then diffuse heat several hours after
combustion.
 airtight stove: outside air is used as air combustion. There is thus no air exchange
between combustion air and inside air. Performances of this technique are higher than a
classic stove and it avoids indoor air quality problems.
Energy efficiency of appliances depends a lot on heat exchange. Therefore, improvements in heat
exchange are always in development. Longer smoke pipe and the use of fan for convection air can be
used. It transfers more energy from flue gases to indoor air and thus improves energy efficiency and
reduces emissions.
Appliances performances depend also on combustion rateload. When the rate of combustionload is
lower than the nominal rate load (reduced combustion), combustion is bad; : emissions are higher and
energy efficiency is lower. This is due to the low temperature in the combustion chamber.

Automatic appliances, which burn pellets or wood chips, enable to operate at a nominal combustion
rate; therefore better performances are obtained better and dust emissions as well other unburnt
pollutants due to incomplete combustion such as CO and VOCs are lower than with manual
appliances.
7.1.2.4 Technologies used with solid fossil fuels

No information is available at the moment concerning technologies using coal.
7.1.3 Available Techniques, Emission Levels

Reducing emissions in domestic combustion mainly means increasing appliances energy efficiency by
using advanced technologies. Nevertheless, so as to achieve the best energy efficiency, measures
taken on appliances have to be followed through by measures on buildings thermal insulation and on
the whole heating network.
Pollutant emissions depend on the type of fuel used:

gaseous fuels use is mainly a source of NO X emissions.
liquid fuels use is mainly a source of SO 2 and NOX emissions.
solid fuels: emissions arising from wood combustion are mainly dust and VOC while emissions
from coal combustion are mainly SO 2 and dust.
Combustion technologies depend also on the type of fuels used. Therefore, available techniques to
reduce emissions from domestic appliances mainly depend on it too.
7.1.3.1 Type of fuel used
Gaseous fuels
Condensing boiler technology combined with the use of a specific burner can be considered as high
efficient technique when gaseous fuels are used. Specific burners enable further re duction especially
low NOx burners for NOx emissions. Micro combustion can also be considered as high efficient
technique with the use of gaseous fuels. [1][1] [2][2]. Mis en forme : Anglais (Royaume-Uni)
Liquid fuels
Mis en forme : Anglais (Royaume-Uni)
Low temperature or condensing boilers combined with the use of specific burners are considered as Code de champ modifié
high efficient technique with the use of liquid fuels. Further NO x emission reductions can also be
achieved by the use of specific burners.
Biomass fuels
For wood logs boilers, inverted combustion with forced draft and recycling of the combustion flue
gases can be considered as high efficient technique. Energy efficiency can be increased and
emissions reduced with the use of a water tank as hydro-accumulator.
The use of pellets as fuel in boilers can also be considered as high efficient technique, so is the use of
condensing technology for solid fuels use.
Dust and VOC emission level mainly depend on the combustion efficiency; the more complete the
combustion is, the lower are the emission levels.
For inserts, the use of catalysts reduces atmospheric emissions of combustion residues by dropping
combustion temperature. This technique is currently used in USA and begins to appear in Europe.
According to measurements reports [10][10] and [11][11], use of catalysts in inserts can divide dust Mis en forme : Anglais (Royaume-Uni)
emissions by two. Code de champ modifié
For stoves, the use of pellets can be considered as a high energy efficiency technique. Mis en forme : Anglais (Royaume-Uni)
Masonry stoves diffuse energy stored during several hours. It allows obtaining a good ambient Code de champ modifié
temperature during several hours without use reduced combustion which produces a lot of pollutants.

However, any technology used to increase energy saving and combustion efficiency, whatever fuel
used, contributes to pollutant emissions reduction by reduction of fuel consumption.
Solid fossil fuels

No information is was available at the moment concerning technologies using coal when the guidance
was drafted.
7.1.3.2 Pollutants
SO2
SO2 emissions depend on the sulphur content of the fuel used. Therefore, the main measure to reduce
SO2 emissions is to use sulphur-free fuels or fuels with low sulphur content. For brown coal, the
addition of calcium hydroxide is possible in order to fix sulphur in the ash.
NOx
NOx emissions are influenced by different parameters such as: the type of fuel, the flame temperature,
the air volume, the residence time in the combustion chamber and the nitrogen content of the fuel.
Available techniques to reduce specifically NO x emissions are the use low NOx burners or premixed
modular air/fuel ratio burner. The premixed modular air/fuel ratio burner enables the NO x formation
reduction in controlling the air content in the mix.
The following table gives an overview of achievable NO x emission levels using selected gas firing
domestic combustion appliances at full load.
Table 1: achievable NOx emissions using selected gas firing domestic combustion appliances.
[2][2] Code de champ modifié
Heat output NOx
(kW) (g/GJ)
Forced air condensing boiler + premixing burner with modular gas/air
24 18
ratio
Forced air boiler + premixed low-NOx burner 24 29
Forced air boiler + conventional burner 24.6 62
Conventional boiler and burner 24.2 85
VOCs
VOC emissions are mainly influenced by the combustion efficiency. There is no technology used to
reduce specifically VOC. Available techniques to reduce VOC emissions are actually the use of
technologies enabling the most complete combustion as possible. These technologies are detailed in
the previous paragraphs concerning wood fuel technologies.
Dust (including PM10, PM2.5 and BC)

In domestic combustion as in combustion in general, dust emissions are influenced by the type of fuel
used. With the use of gGaseous fuels have very low dust emissions are considerably low and gas can
be used to substitute coal and/or wood. or For57 liquid fuels, dust emission are also low. measures to
improve energy efficiency are primary Primary measures to reduce dust emissions are presented in
chapter 7.1.2.1 and 7.1.2.2.. They are the only measures considered in this chapter to reduce dust
emission from gaseous or liquid fuels use.
Solid fuels are the main source of dust emissions. Available techniques to reduce dust emissions are
foremost primary measures enabling the most complete combustion as possible. These techniques

have been described in the previous paragraphs concerning wood fuel technologies. Dust emissions
from existing appliances can be obtained by replacing them with modern appliances showing higher
energy efficiency and better combustion conditions.
Besides those technical measures, especially for manually operated wood stoves and boilers, proper
operation and quality of fuel are essential to avoid high-pollutant emissions in practice. Ignition of the
wood from the top instead of ignition from the bottom significantly reduces e missions from the start-up
phase. Throttling the combustion air leading to low heat loads needs to be strictly avoided . [15]. The
use of untreated wood only and the correct seasoning of wood for moisture content are also very
important prerequisites. Public information programs can help in raising the awareness for these
requirements [15].
Secondary measures to reduce dust emissions can also be considered with the use of solid fuels. The
proven technologies for dust removal are multicyclones, electrostatic precipitators (ESP) and fabric
filters which are described in more detail in paragraphs 6.5 and 7.1.2.3.
Studies have shown that ESP and fabric filters are suited in the range <1 MW down to 100 kW [8][8].
For installations < 500 kW, costs are still relatively high, but there is positive experience with some
3
reference installations in this range. Dust emission reductions below 50 mg/m (13% O2) can be
reached with a simple (1-stage) ESP, while reductions to 10-20 mg/m³ (13% O2) have been
demonstrated with optimized (multi-stage) ESP. Fabric filters can reduce dust emissions to < 10 or
even <5 mg/m³ [8][8], [15]. Mis en forme : Police :10 pt, Anglais
(États Unis)
Small-scale electrostatic precipitators (ESP) have been developed in some countries, e.g. Norway,
Germany and Switzerland [8] [13], [15], [17], and can be considered as available techniques to reduce Code de champ modifié
dust emissions from domestic wood combustion appliances < 50 kW including single-room heaters. Mis en forme : Police :10 pt, Anglais
Under ideal conditions small-scale ESP can reduce 90 % of the dust particles with a diameter superior (Royaume-Uni)
to 0.1 µm [7][7]. However these separators are often based on a design which for cost reasons is Mis en forme : Police :10 pt, Anglais
simplified compared to industrial applications. In some cases only moderate separation efficiencies (Royaume-Uni)
below 50% may be expected, especially when there is re-entrainment after agglomeration of particles. Code de champ modifié
Field tests have shown that small-scale ESP now available on the market are only effective on the
long-term when used with modern combustion installations enabling a rather complete and clean Mis en forme : Police :10 pt, Anglais
(Royaume-Uni)
combustion. Older combustion installations with poor combustion technology and correspondingly high
particulate emissions may quickly lead to overload and clogging [8][18]. In the current state of the art a Mis en forme : Police :10 pt, Anglais
general retrofitting of older installations with small-scale ESP is not recommended. (Royaume-Uni)
More generally, dust is deposited in the stoves, boilers, ducts, stacks, etc. Thus, to limit emissions of
dust, boilers or stoves need to be cleaned regularly. Self cleaning option can also be seen as an Mis en forme : Anglais (Royaume-Uni)
efficient technique for the dust reduction. Code de champ modifié
Table 2: achievable dust emission levels of biomass combustion appliances < 1 MW [2][16] Code de champ modifié
Appliance type 1. Secondary 2. Achievable Mis en forme : Centré, Sans
abatement dust emission numérotation ni puces
technology level
3
3. mg/mn
at 13% O2
Wood stoves and 20 - 40
closed insert
appliances
Log wood boilers 15 -30
(with heat storage
tank)
Pellet stoves & 15 - 30
boilers
Automatic wood multicyclone 75 - 150
boilers
simple ESP 20 - 50
improved ESP < 10 - 20
fabric filter < 10

Focus on black Carbon (BC)

Residential combustion - especially biomass combustion - is and remains in the future a key BC
emitting sector. Soot (found as BC in the atmosphere) is formed under conditions of incomplete
combustion in zones of high temperatures and lack of oxygen. Incomplete combustion is often found
in manually operated combustion. Hence manually operated wood stoves and small-size boilers are
the main BC sources in this source category.
Available techniques to reduce BC emissions are the same technical primary measures as described
above for dust reduction by enabling the most complete combustion as possible. Especially staged
combustion comprising lower temperature gasification will reduce soot formation by reducing fuel rich,
high temperature zones in the flame. Again - as for dust reduction - proper operation of manually
operated appliances and quality of fuel are also essential for BC reduction [15].
In automatic combustion installations - automatic wood boilers, pellet stoves and boilers - nearly
complete combustion can be achieved and hence inorganic particles are dominant as dust
components. However, during start-up, and in phases of inappropriate operation, soot can also be
emitted from automatic installations [15].
Concerning secondary measures, in general electrostatic precipitators (ESP) and fabric filters will
reduce BC. Soot has a high electrical conductivity thus enabling high separation efficiency in ESPs but
severe re-entrainment of agglomerated particles can occur. Multicyclones will not reduce BC to any
significant degree, since they have a poor separation efficiency for particles smaller than 5 microns
[15].
For small-scale ESPs marketed for use with domestic stoves and boilers, the BC reduction potential in
practice is uncertain for most applications and hence further experience is needed [8][18]. Code de champ modifié
7.1.4 Emerging techniques

The micro-cogeneration is an emerging technique to reduce energy consumption. The energy use for
home heating or sanitary water heating is also used to produce electricity.
The use of pellets which is being developed for inserts technology increases energy efficiency.
Ceramic filters have been used for large industrial installations over longer periods. For small
combustion installations, ceramic filters have been developed that use the same technology as
particle traps for diesel engines in vehicles and vessels. These soot filters also reduce emissions of
BC. Ceramic filters can also be used in oxidation installations. The ceramic material transfers the heat
for the oxidation reaction or functions as a catalyst. This way unburned material like BC can be
oxidised. These emission abatement systems have been developed and tested in practice but not
enough data are available to assess the availability for stationary combustion plants < 1 MW. It is
expected that the development of this abatement technique will benefit from the use of particle
traps on heavy duty vehicles and that this will become an available technique for small combustion
plants burning solid fuels in the near future [19].
7.1.5 Cost data for emission reduction technique

The investment cost of a low-NOx boiler is about 500 euros more than for a conventional boiler Mis en forme : Anglais (Royaume-Uni)
[10][10]. Code de champ modifié
The investment cost for a wood boiler with inverted combustion and forced draft is from 3 000 to 7 650 Code de champ modifié
euros, for installations from 15kW to 150kW. An investment for heat accumulator is from 1 500 to Mis en forme : Anglais (Royaume-Uni)
2 750 euros [10][10], [12][12].
The investment cost for a pellet boiler is 7 000 to 15 000 euros for installations from 15 kW to a few Mis en forme : Anglais (Royaume-Uni)
MW [12][12].


According to Swiss studies [13][13], the investment cost for a small-scale ESP reducing at least 60 %
of dust emissions would be 1 000 to 1 500 euros for installations < 35 kW. Mis en forme : Anglais (Royaume-Uni)
Additional cost of catalysts addition in inserts is about 1 000 euros [14][14]. Mis en forme : Anglais (Royaume-Uni)

Table 2: investment per kW heat output for wood heating systems and dust abatement
1
equipment [8][8] Code de champ modifié
Technology (heater system) Building (without silo) ESP FF

Power [kW]
[€/kW] [€/kW] [€/kW] [€/kW]
100 965 520 660 450
200 800 430 405 240
500 630 340 195 115
1000 420 225 115 70
2000 315 170 75 50
7.1.6 References used in chapter 7.1

[1] L’énergie en region Wallone: http://energie.wallonie.be
[2] Atmospheric emissions from gas fired home heating appliances, Cernushi, Consonni, Lonati,
Giugliano, Ozgen, EGTEI report.
[3] GFCC, groupement des fabricants de chauffage central par l’eau chaude et production d’eau
chaude sanitaire.
[4] ADEME website, les chaudières performantes:
http://www.ademe.fr/particuliers/Fiches/chaudiere_performante/rub3.htm
[5] ADEME, “fiche OX NOx « chaudière à combustion pulsatoire »”, 2002.
[6] “Emissions characteristics of modern and old-type residential boilers fired with logs and wood
pellets”, L.S. Johansson and alls. Atmospheric environment, 38 (2004) 4183-4195
[7] “Petites chaudières du secteur industriel et tertiaire et appareils domestiques de chauffage au
bois…”, , Inventaires d’émissions, règlementations, performances et coûts des technologies Mis en forme : Police :10 pt, Non
avancées de réduction des émissions ”, INERIS, CITEPA, 2007 for the French ministry of Surlignage
ecology..
[8] “Stand der Technik und Kosten der Feinstaubabscheidung für automatische Holzfeuerungen
von 100 kW bis 2 MW”, Verenum, Bundesamt für Umwelt, Abteilung Luftreinhaltung & Kanton
Thurgau, Amt für Umwelt, Abteilung Luftreinhaltung, Zürich 2006.
[9] “Estimation de l’impact environnemental du chauffage domestique au bois à l’échelle
Locale locale », ADEME, 2008.
[10] Bericht über die Erstprüfung eines Kamineinsatzes für feste Brennstoffe vom Typ „“ULYSS 700“
nach DIN EN 13 229, Fraunhofer Institut, 17/04/2008.
[11] Ergebnisse aus der Prüfung der Nennwärmeleistung nach DIN EN 13 229 des Kamineinsatzes
“ULYS 700ZE“ der Firma Fondis SA, Fraunhofer Institut, le 13/11/2008.
[12] Bioenergy institute website, www.ITEBE.org: "technologies pour les particuliers".
[13] Volker Schmatloch, EMPA Swiss federal institute for Materials Research and testing, “exhaust
gas aftertreatment for small wood fired appliances - recent progress and field test results”.
[14] Interview’s report of M. Haas technical director of Fondis, 19/03/2009.
[15] Nussbaumer T., Overview on Technologies for Biomass Combustion and Emission levels of
Particulate Matter, prepared for the Swiss Federal Office for the Environment and EGTEI, 2 010.
[16] Options for limit values for emissions of dust from small combustion installations < 50 MWth,
report of the Subgroup on Small Combustion Installations under EGTEI, 2010.
1
Data from 2005/2006, converted to € (1 SFR= 0,64523 €) and rounded ; for calculation details see source report

[17] http://www.ruegg-cheminee.com/ww/de/pub/produkte/partikelabscheider/vorteile.htm
[18] H. Hartmann et al., Electrostatic precipitators for small-scale wood combustion systems –
Results from lab- and field tests, Central European Biomass Conference (CEBC), 26.-
28.January 2011 in Graz,
http://www.biomasseverband.at/uploads/tx_osfopage/WSF_5_Hartmann.pdf.
[19] http://www.econergy.ltd.uk/docs/files/Case%20studies/Greenland.pdf


7.2 Combustion Installation from 1 to 50 MW
7.2.1 Coverage
This section covers emissions from boiler installations and gas turbines with a net thermal input
between 1 and 50 MW th. In the following, the term “boilers” is meant in contrast to combustion engi nes
or turbines and includes all kinds of boilers and process heaters.
The following installations are not covered by this section:
plant in which the products of combustion are used for direct heating, drying, or any other
treatment of objects or materials, e.g. reheating furnaces, furnaces for heat treatment;
post-combustion plant, i.e. any technical apparatus designed to purify the waste gases by
combustion that is not operated as an independent combustion plant;
facilities for the regeneration of catalytic cracking catalysts;
facilities for the conversion of hydrogen sulphide into sulphur;
reactors used in the chemical industry;
coke battery furnaces;
cowpers;
waste incinerators;
and
plant powered by diesel, petrol or gas engines, irrespective of the fuel used (For information
about stationary engines see document "New stationary Engines" 7-41)

Within the sector, the technologies used for the combustion of liquid and gaseous fuels are similar to
those for production of thermal energy in industrial combustion activities.
For the combustion of solid fuels and biomass mainly fixed bed combustion technology, i.e. grate -
firing, is applied.
Fluidized bed combustion technologies are also used in the sector. This technology is m ost
appropriate for co-combustion of coal with biomass and/or with waste fuels, or combustion of biomass
Gas turbines are used for the transformation of thermal energy into mechanical energy. They use a
steady flow of a gas (mostly air), compressed and fired with gaseous or liquid fuel.
7.2.3 Available Techniques, Associated Emission Levels (AEL)

Emissions within the sector strongly depend on the fuel, combustion technologies as well as on
operational practices and maintenance. For solid fuels specific emissions are higher in smaller than in
larger plants. For gaseous and liquid fuels, the emissions are not significantly higher in comparison to
industrial scale boilers due to the quality of fuels and design of burners [1].[1]

7.2.3.1 SO2
Table 1: emission sources and selected SO2 control measures with associated range of
emission levels (solid and liquid fuels) resp. upper emission level (gaseous fuels) in
combustion installations between 1 and 50MWth [1]
3
Emission source Control measures SO2 emission level (mg/Nm )
Solid fuel
Use of low-sulphur fuel,
Boilers other than fluidized
Sorbent injection, 50-1000
bed combustion (FBC)
Flue gas desulphurisation,
Fluidized bed combustion Sorbent injection, 50-400
Flue gas desulphurisation,
Liquid fuel
Boilers Sorbent injection, 50-850
Flue gas desulphurisation
Gaseous fuel
Boilers: Refinery gas Use of low-sulphur fuel, 100
Boilers: Liquefied gas Sorbent injection, 5
Boilers: Other gaseous fuel Flue gas desulphurisation 35
If not stated otherwise, values are daily averages assuming an oxygen content by volume in the waste gas of
3 % in the case of liquid and gaseous fuels, 6 % in the case of solid fuels.
3
If emission reduction measures are regarded, for low sulphur fuels a level of 700 mg/Nm can be
3
reached, for sorbent injection a level of 200 - 400 mg/Nm and for desulphurisation a level of 50 – 200
3
mg/Nm .

7.2.3.2 NOx
Table 2: emission sources and selected NOx control measures with associated upper emission
levels in combustion installations between 1 and 50MW th [1], [2][1], [2]
3
Emission source Control measures NOx emission level (mg/Nm )
Solid fuel
Grate firing Low-NOx burner
Air staging
< 200-400
Flue gas recirculation
Boiler design
Pulverized coal Low-NOx burner
Air staging
< 200-400
Boiler design
Air staging
Flue gas recirculation < 200-500
Fluidized bed combustion Boiler design
SNCR < 50-100

Liquid fuel
Low-NOx burner
Air staging
Boiler < 200-300
Boiler design
Gaseous fuel
Low-NOx burner
Air staging
Boiler < 200
Boiler design
Existing Gas-Turbines
Water and steam injection or
Fuel: natural gas 50-120
SCR
Water and steam injection or SCR
Fuel: diesel oil or process gas
New Gas-Turbines
Dry low-NOx premix burner or SCR
Fuel: natural gas 20-50
If not stated otherwise, values are daily averages assuming an oxygen content by volume in the waste gas of
3 % in the case of liquid and gaseous fuels, 6 % in the case of solid fuels and 15 % in the case of gas
turbines.

7.2.3.3 Dust (including PM10, PM2.5 and BC)

Table 3: emission sources and selected dust control measures with associated range of
emission levels in boiler installations between 1 and 50 MWth [1] [1]
3
Emission source Control measures Dust emission level (mg/Nm )
new existing
Cyclone < 50 < 100
Solid fuel, 1- to 5 MWth ESP 5 - 20 5 - 30
FF 5 - 20 5 - 20
ESP 5 - 20 5 - 30
Solid fuel, 5 - to 50 MWth
FF < 5 - 20 < 5 - 20
ESP 5 - 50 5 - 50
Liquid fuels, 1- to 5 MWth FF < 5 – 20 < 5 – 20
Use of low ash fuel < 5 - 50 < 5 - 50
ESP 5 - 20 5 - 50
Liquid fuels, 5 - to 50 MWth
FF < 5 - 20 < 5 - 20
Gaseous fuels 2-5 2-5
If not stated otherwise, values are daily averages at standard conditions assuming an oxygen content by
volume in the waste gas of 3 % in the case of liquid and gaseous fuels, 6 % in the case of mineral solid
fuels, 11 % in the case of wood
Because BC is formed during incomplete combustion. I, it is mainly associated to particles with a
diameter less than 1 µm. In such combustion installations, BC content of dust can increase during
start-up and shut-down periods. A smooth, continuous and optimised combustion reduces dust
(including PM10, PM2.5 and BC) emissions as described in chapter 6.4. OOnly reduction techniques
able to remove fine particles will have a significant efficiency on BC emissions. In such combustion
installations, BC content of dust increases during start-up and shut-down periods. Combustion
technique optimisation reduces dust (including PM10, PM2.5 and BC) emissions as described in chapter
6.4. Chapter 6.5 provides information on the efficiency of ESP and FF for dust (including PM10, PM2.5
and BC).

[1] European Commission: Kubica. K; Paradiz. B; Dilara. P: Small combustion installations:
Techniques, emissions and measures for emission reduction, 2007
[2] German TA Luft - Technische Anleitung zur Reinhaltung der Luft, Erste Allgemeine
Verwaltungsvorschrift zum Bundes-Immissionsschutzgesetz, Germany
[3] The association for British Furniture Manufacturers: Benchmarking wood waste combustion in the
UK furniture manufacturing sector, 2005

7.3 Combustion Installations larger than 50 MW
7.3.1 Coverage
The combustion sector covers a range of different combustion techniques suited to different fuels:
solid fuels, such as coal, lignite, peat, biomass, liquid and gaseous fuels, including low calo rific and
blast furnace gas. This section covers boilers (small: 50 - 100 MW th, medium: 100 - 300 MW th, and
large: > 300 MW th) and gas turbines (> 50 MW el). In the following, the term “boilers” is meant in
contrast to combustion engines or turbines and includes all kinds of boilers and process heaters. The
given capacity classes in terms of rated thermal input refer to the lower heating value (LHV) of the
respective fuel.
The following installations are not covered by this section:
plant in which the products of combustion are used for direct heating, drying, or any other
treatment of objects or materials, e.g. reheating furnaces, furnaces for heat treatment;
post-combustion plant, i.e. any technical apparatus designed to purify the waste gases by
combustion that is not operated as an independent combustion plant;
facilities for the regeneration of catalytic cracking catalysts;
facilities for the conversion of hydrogen sulphide into sulphur;
reactors used in the chemical industry;
coke battery furnaces;
cowpers;
waste incinerators;
and
plant powered by diesel, petrol or gas engines, irrespective of the fuel used (For information
about stationary engines see document "New stationary engines" 7-41)
7.3.2 Emission sources

The combustion process leads to the generation of emissions to air, which are considered to be one of
the major sources of air pollution. Depending on the type of the fuels, several combustion technologies
are available which show considerably different NO x, SOx and dust (including PM10, PM2.5 and BC)
emissions. This paragraph describes the main technologies used for the combustion of solid, liquid
and gaseous fuels.
(a) Large boilers, process heaters and furnaces
Grate firing is used in comparatively small combustion plants with a thermal capacity of less than 100
MW th sometimes grate firing is used for burning waste (not regarded in this chapter, cf. 7-18) and
biomass [1]. The fuel on the grate will be first dried and pyrolysed. And then the char is burned on the
grate. The conditions of combustion are not as well controlled as in other systems as the combustion
chemistry and the temperature can vary considerably across the grate [2].
Pulverised fuel firing is well established for all sizes of boiler above 50 MW th and is a solid fuel
burning technique in which the fuel is pulverised before being ignited. Two general boilers types are
distinguished:
Dry bottom boilers operate at lower temperatures so that the ash is not heated above its melting
point during the combustion process.
Wet bottom boilers require high combustion temperatures in order to melt the ash; accordingly,
comparatively high NOx emission levels are observed [1]. This technique is often used for fuels with
poor combustion characteristics and involves recycling fly ash [3].

Fluidized bed combustion (FBC) is a combustion technology for burning hard coal and lignite, but
also low-grade fuels such as waste, peat and wood, which are not regarded in this section. Fuel is
injected into a hot turbulent bed of reactive or inert material while a flow of air passes up through the
bed. Emissions can be further reduced via integrated combustion control in the system. Within the
sector of energy conversion, atmospheric fluidized bed combustion is a well-established commercial
technology. Depending on the velocity of the fluidisation air, two types of atmospheric fluidised bed
combustion do exist, the atmospheric bubbling fluidised bed combustion (BFBC), and the atmospheric
circulating fluidised bed combustion (CFBC). Pressurized fluidized bed combustion (PFBC) operates
at elevated pressures and produces a high-pressure gas stream at temperatures that can drive a gas
turbine.
(b) Turbines
Gas turbines are used for the transformation of thermal energy into mechanical energy. They use a
steady flow of a gas (mostly air), compressed and fired with gaseous or liquid fuel. Gas turbines are
increasingly used for electricity production in base and intermediate load but are also still used for
peaking load in simple cycle (then fired with gas or light oil). In combined cycle power plants a gas
turbine is combined with steam turbine to generate electricity.
Integrated gasification combined cycle (IGCC) process incorporates coal or biomass gasification
and combined cycle plants. The gasified solid fuel is burned in the combustion chamber of the gas
turbine. The technology also exists for heavy oil residue. However, this process is not yet fully
commercialized, a small number of demonstration units, mainly around 250 MWe size are being
operated in Europe and the USA.
BAT for the combustion of solid, liquid and gaseous fuels

Combustion of coal and lignite
Pulverized combustion, fluidized bed combustion as well as pressurized fluidized bed combustion and
grate firing are all considered to be BAT for the combustion of coal and lignite for new and existing
plants. Grate firing should preferably only be applied to new plants with a rated thermal input below
100 MW [3].
Combustion of biomass and peat
For the combustion of biomass and peat, pulverized combustion, fluidized bed combustion as well as
the spreader stoker grate firing technique for wood and vibrating, water-cooler grate for straw-firing are
BAT. Pulverized peat combustion plants are not BAT for new plants [3].
Combustion of liquid fuels
For liquid fuels, the use of pretreatment devices, such as diesel oil cleaning units used in gas turbines
and engines, are BAT. Heavy fuel oil (HFO) treatment comprises devices such as electrical or steam
coil type heaters, de-emulsifier dosing systems, etc.
Combustion of liquid and gaseous fuels in CHP plants
A combined cycle operation and cogeneration of heat and power is to be considere d as the first BAT
option, i.e. whenever the local heat demand is great enough to warrant the construction of such a
system [3].
7.3.3 BAT, Associated Emission Levels (AEL)
7.3.3.1 SO2
This section provides descriptions of the abatement options that are generally used to reduce
emissions of sulphur oxides from combustion installations. Emissions of SO 2 are highly dependent on
the sulphur content in coal burned and the emissions control system employed. In general, techniques
to reduce sulphur oxides are divided into primary and secondary measures.

Primary measures
Use of low sulphur fuel, the SO2 emissions during combustion are directly related to the sulphur
content of the fuel used. Fuel switching (from high- to low-sulphur fuels) leads to lower sulphur
emissions. This measure is widely applied. However there may be certain restrictions, such as the
availability of low-sulphur fuels and the adaptability of existing combustion systems to different fuels.
Fuel switching to natural gas can be sufficient for reducing SO 2, in case of other fuels depending on
the fuel sulphur content it can be used as a supplementary technique.
Use of alkaline sorbents in fluidised bed combustion systems.

FBC boilers can operate very efficiently in terms of SO2 removal, for example sorbent injection into the
FBC boiler is an inexpensive method for sulphur capture. Investment costs are low, because the
desulphurisation is incorporated into the combustion process and separate reactor equipment is not
needed [3]. However, the solid by-products composed of ash, sulphate containing reaction products
and lime cannot be used for concrete making as fly ash from conventional PC combustion
Secondary measures
Flue gas desulphurisation (FGD) processes. These processes aim at removing already formed
sulphur oxides, and are also referred to as secondary measures. The state -of-the-art technologies for
flue gas treatment are all based on the removal of sulphur by wet or dry processes.
In wet processes, wet slurry waste or by-product is produced, and flue gas leaving the absorber is
saturated with moisture. Seawater scrubbing utilises seawater’s inherent properties to absorb and
neutralise sulphur dioxide in flue-gases. If a large amount of seawater is available near a power plant,
it is most likely to be used as a cooling medium in the condensers. Wet scrubbers, especially the
limestone-gypsum processes, are the leading FGD technologies. They have about 80% of the market
share and are used in large utility boilers. The efficiency of sulphur dioxide removal may be increased
up to 92-98%. In case of retrofitting the efficiencies are lower reaching up to 95%.
In semi-dry processes, a slurry of alkaline reagent is atomized and injected into a vessel where it
reacts with the SO2 in the flue gas to produce calcium sulphate or sulphite products [4]. Sulphur
dioxide removal efficiencies of 80 to 95% have been achieved.

Table 1: emission sources and selected BAT SOx control measures with associated emission
levels in combustion installations (PM is for primary measures)
Combination of control SOx emission level associated

Emission source 1 3
measures with BAT (mg/Nm ) [3]
boilers 50 - 100 MWth
Grate-firing, Fuel: coal and lignite Low sulphur fuel or FGD 200 - 400
Boiler; 200 - 400
Low sulphur fuel and FGD
Fuel: coal and lignite (split view industry: 200 - 300)
Circulating FBC; Pressurised Low sulphur fuel 150 - 400
FBC; Fuel: coal, lignite Limestone injection (split view industry: 150 - 300)
Bubbling FBC; Low sulphur fuel 150 - 400
Fuel: coal, lignite FGD (split view industry: 150 - 300)
Limestone injection
Boiler; Calcium hydroxide injection in 200 - 300 (new)
dry form before the ESP or
Fuel: peat FF 200 - 300 (existing)
FGD
Co-combustion of biomass
and peat
Limestone injection
Circulating FBC; Bubbling FBC; 200 - 300 (new)
Calcium hydroxide injection in
Fuel: peat 200 - 300 (existing)
FF
FGD
100-350 (new)
Low sulphur fuel oil
Boiler; 100-350 (existing)
Co-combustion of gas and oil
Fuel: oil (split view industry: new plants:
FGD
200-850, existing plants: 200-850)
Boilers 100 - 300 MWth
Low sulphur fuel 100 - 200 (new)
Boiler; FGD 100 - 250 (existing)
Fuel: coal and lignite Combined techniques for the (split view industry: existing plants
reduction of NOx and SOx 100-600)
100 - 200 (new)
Circulating FBC; Pressurised Low sulphur fuel 100 - 250 (existing)
FBC; Fuel: coal, lignite Limestone injection (split view industry: existing plants:
100-300)
100 - 200 (new)
Bubbling FBC; Low sulphur fuel 100 - 250 (existing)
Fuel: coal, lignite FGD (split view industry: existing plants
100-300)
Limestone injection
Boiler; Calcium hydroxide injection in 200 - 300 (new)
Fuel: peat FF 200 - 300 (existing)
FGD
and peat
Circulating FBC; Bubbling FBC; Limestone injection 150 - 250 (new)
Fuel: peat Calcium hydroxide injection in 150 - 300 (existing)
FF,

FGD

Co-combustion of gas and oil 100 - 200 (new)
Boiler; and FGD 100 - 250 (existing)
Fuel: oil FGD (split view industry: new plants:
Combined techniques for the 100-400, existing plants: 100-400)
reduction of NOx and SOx
Boilers >300 MWth
Low sulphur fuel 20 - 150 (new)
FGD 20 - 200 (existing)
Boiler; Fuel: coal and lignite
Combined techniques for the (split view industry: new plants:
reduction of NOx and SOx 20-200, existing plants: 20-400)
100 - 200 (new)
Circulating FBC; Pressurized Low sulphur fuel 100 - 200 (existing)
FBC, Fuel: coal, lignite Limestone injection (split view industry: existing plants:
100-300)
20 - 150 (new)
Low sulphur fuel 20 - 200 (existing)
Bubbling FBC, Fuel: coal, lignite
FGD (split view industry: existing plants:
20-300)
FGD
50 - 150 (new)
Boiler; Fuel: peat Combined techniques for the
50 - 200 (existing)
reduction of NOx and SO2
and peat
Limestone injection
Circulating FBC; Bubbling FBC 50 - 200 (new)
Fuel: peat Calcium hydroxide injection in
50 - 200 (existing)
FF
FGD
50 - 150 (new)
Co-combustion of gas and oil
50 - 200 (existing)
Boiler, Fuel: oil FGD
(split view industry: new plants:
Combined techniques for the 50-200, existing plants: 50-400)
reduction of NOx and SOx
1
The BAT associated emission levels are based on a daily average, standard conditions and
represents a typical load situation. For peak load, start up and shut down periods, as well as for
operational problems of the flue gas cleaning systems, short-term peak values, which could be higher,
have to be regarded.
If not stated otherwise, values are daily averages assuming an oxygen content by volume in the waste
gas of 3 % in the case of liquid and gaseous fuels, 6 % in the case of solid fuels.
7.3.3.2 NOx
The most important oxides of nitrogen with respect to releases from combustion processes are nitric
oxide (NO), nitrogen dioxide (NO2) and nitrous oxide (N 2O). NO and NO2 are commonly referred to as
NOx. [2]. NOx is formed during most combustion processes by one or more of three chemical
mechanisms: “thermal” NOx resulting form oxidation of atmospheric molecular nitrogen, “fuel” NO x
resulting from oxidation of chemically bound nitrogen in the fuel, and “prompt” NOx resulting from

reaction between atmospheric molecular nitrogen and hydrocarbon radicals [4]. Only the first two
mechanisms are of major importance in combustion plants.
This section provides descriptions of the abatement options that are generally used to reduce
emissions of nitrogen oxides from combustion installations. In general, techniques to reduce nitrogen
oxides are divided into primary and secondary measures. Primary measures have been developed to
reduce NOx emissions at source during the combustion process by regulating flame characteristics
such as temperature and fuel-air mixing. Secondary measures operate downstream of the combustion
process and remove NOx emissions from the flue gas.
The application of primary measures is limited by operational and fuel specific parameters that
influence the safe operation. It is also limited by layout feasibility in existing i nstallations.
Primary measures (combustion modifications):

Air staging consists of the introduction of combustion air into primary and secondary flow sections to
achieve complete burnout and to encourage the formation of N 2 rather than NOx. The primary
combustion zone has a lack of oxygen and the secondary combustion zone an excess of oxygen. This
technique is frequently used in conjunction with low NO x burners, completes the combustion process
at a lower temperature [1], [5].
Fuel staging, also named reburning is a three-stage (zone) system. It is based on the creation of
different zones in the furnace by staged injection of fuel and air. The aim is to reduce nitrogen oxides,
which have already been formed back to nitrogen [1]. The reburning technique is capable of achieving
relatively high NOx reduction (50-75%) and can in principle be used at all types of fossil fuel fired
boilers, and also in combination with low-NOx combustion techniques for the primary fuel. This
technique is not well adapted for retrofit due to space constraints.
Flue gas recirculation results in a reduction of available oxygen in the combustion zone and, since it
directly cools the flame, in a decrease of the flame temperature: therefore, both fuel bound nitrogen
conversion and thermal NOx formation are reduced. The recirculation of flue gas into the combustion
air has proven to be a successful method for NO x abatement at high temperature combustion systems
such as wet bottom boilers and oil or gas fired installations but is generally not effective on dry bottom
pulverised coal boilers. NOx emissions reduction of 30-60% can be observed by employing flue gas
recirculation when burning natural gas. On heavy fuel oil NOx reductions of 10-20% are observed but
dust emissions may increase
Low NOx Burners (LNB) are designed to control the mixing of fuel and air to achieve what amounts to
staged combustion. An under-stoichiometric zone is created with a fuel/air mixture and primary air.
Due to the swirl of primary air, internal recirculation occurs. Around the primary air nozzles, an
arrangement of secondary nozzles feeds secondary air to the burnout zone. This staged combustion
reduces both flame temperature and oxygen concentration during some phases of combustion, in turn,
produces both lower thermal NOx and fuel NOx generation. Low NOx Burners should be fitted to all
new plant and retrofitting to existing plant should normally be expected. Low NO x-Burners are effective
in reducing NOx emissions by 30-50% [1] [5] and can be combined with other primary measures such
as overfire air, reburning or flue gas recirculation.
Secondary measures (post combustion NO x control technology)

Selective Catalytic Reduction (SCR) is the most mature and widely applied process for the reduction
of nitrogen oxides in exhaust gases from combustion installations in Europe and other coun tries such
as Japan and the U.S. The SCR process can be used for a wide range of fuels such as natural gas.
The SCR process usually uses ammonia as a reducing agent, which is directly injected into the flue
gas over a catalyst in the presence of sufficient oxygen. NOx-conversion takes place on the catalyst
surface at a temperature between 170 and 510°C (with a range between 300 and 400°C being more
typical; the minimum flue gas temperature is dependent on the sulphur content of the fuel. At a too
low flue gas temperature ammoniumbisulphate is formed which will clog the SCR element) [3] NOx
emission reductions over 80-90% are achieved and depend on the system design, catalyst activity and
the concentration of reacting gases [2].
Selective Non-Catalytic Reduction (SNCR) reduces NOx and operates without a catalyst at a
temperature between 850 and 1100°C. This temperature window is strongly dependent on the

reactant used, which can be: ammonia, urea or ammonia solution. The SNCR process has found
application for various types of fossil fuels. The average achievable NO x abatement efficiency is in the
range of 30-50% [3]. SNCR is less costly than SCR because of the absence of catalyst and can be
applied also at small installations. But SNCR is not well suited for plants, which are operated at
variable load (risk of excessive ammonia slip and smell).
BAT for reducing nitrogen oxide emissions

Combustion of lignite and coal
For NOx removal of off-gases from coal and lignite combustion plants, the use of a combination of
primary and/or secondary measures is considered to be BAT. However according to the boiler
technology and coal type (e.g. high primary NOX for low volatile coals) a distinction of BAT has to be
made.
The combination of primary measures in combination with secondary measures such a SCR is
considered to be BAT for base load pulverized coal combustion plants.
The use of a combination of different primary measures for pulverized lignite-fired plants is considered
to be BAT. Because of lower NO x emissions in lignite-fired plants, the SCR technique is not
considered to be BAT for the combustion of lignite.
The use of staged combustion for the fluidized bed combustion of coal and lignite is considered to be
BAT.

For NOx removal of off-gases from biomass and peat combustion plants, the use of a combination of
primary and/or secondary measures is considered to be BAT. However according to the boiler
technology a distinction of BAT has to be made.

For NOx removal of off-gases from liquid-fuel fired combustion plants, the use of a combination of
primary and/or secondary measures such as a SCR is considered to be BAT for over 50 MW th and in
particular for large baseload plants above 100MW th.
The use of a combination of different primary measures is considered to be BAT for combustion plants
with a capacity of less than 100 MW th.
Combustion in Gas Turbines

For new gas turbines, dry low NOx premix burners (DLN) are BAT. For existing gas turbines, water
and steam injection as primary measure or conversion to the DLN technique is BAT. DLN burners are
only BAT for new turbines where the technique is available on the market for the use in gas turbines
burning liquid fuels.

Table 2: emission sources and selected BAT NOx control measures with associated emission
levels in combustion installation (PM is for primary measures)
Combination of control NOx emission level associated

Emission source 1 3
200 - 300
Grate firing, Fuel: coal and lignite PM and or SNCR (split view industry: existing plants:
200-400)
90 - 300
Combination of PM, SNCR or
Boiler; Fuel: coal (split view industry: new plants:
SCR
90-450, existing plants: 90-500)
200 - 450
Boiler; Fuel: lignite Combination of PM (split view industry: existing plants:
200-500)
Circulating FBC; Pressurised
FBC Bubbling FBC, Fuel: coal, Combination of PM 200 - 300
lignite
Grate firing, Fuel: biomass and 170 - 250 (new)
Spreader-stocker
peat 200 - 300 (existing)
150 - 250 (new)
Boiler; Fuel: biomass and peat Combination of PM or SCR
150 - 300 (existing)
Circulating FBC; Bubbling FBC, 150- 250 (new)
Combination of PM
Fuel: biomass and peat 150 - 300 (existing)
150- 300 (new)
Combination of PM
Boiler, Fuel: oil SCR
SNCR in case of HFO firing
150-400)
50 - 100 (new and existing)
Low NOx-Burners or SCR or
Industrial boiler; fuel: gas (split view industry: new and
SNCR
existing: 50-120)
90-200 (new)
Combination of PM in 90 - 200 (existing)
Boiler; Fuel: coal combination with SCR or (split view industry: new plants:
combined techniques 100-200, existing plants: 90-300)
100 - 200 (new)

Boiler; Fuel: lignite Combination of PM
(split view industry: existing plants:
100-450)
100 - 200 (new)
Circulating FBC; Pressurized Combination of PM, if
FBC Bubbling FBC, Fuel: coal, necessary, together with
lignite SNCR (split view industry: existing plants:
100-300)
Combination of PM, if 150 - 200 (new)
Boiler; Fuel: biomass and peat
necessary SNCR and/or SCR 150 - 250 (existing)
Circulating FBC; Bubbling FBC, 150 - 200 (new)
Combination of PM
Combination of PM in 50 - 150 (new)
Boiler, Fuel: oil combination with SNCR, SCR 50 - 200 (existing)
or combined technique (split view industry: new plants:

50-200; existing plants: 50-450)

Low NOx burners or SCR or 50 - 120 -100 (3% O2)
Industrial boiler; fuel: gas
SNCR (split view industry: 50-120)
Boilers >300 MWth
Combination of PM in 90 - 150 (new)
Boiler; Fuel: coal combination with SCR or 90 - 200 (existing)
combined techniques
50 - 200 (new)
50 - 200 (existing)
Boiler; Fuel: lignite Combination of PM
50 - 150 (new)
Circulating FBC; Pressurized
50 - 200 (existing)
FBC Bubbling FBC, Fuel: coal, Combination of PM
lignite (split view industry: existing plants:
100-200)
Combination of PM, if 50 - 150 (new)
necessary SCR or and SNCR 50 - 200 (existing)
Circulating FBC; Bubbling FBC, Combination of PM, if 50 - 150 (new)
Fuel: biomass and peat necessary SCR or and SNCR 50 - 200 (existing)
50- 100 (new)
Combination of PM in
50 - 150 (existing)
Boiler, Fuel: oil combination with SCR or
combined techniques (split view industry: new plants:
New CCGT without Dry low-NOx premix burners
20-50
supplementary firing or SCR
Dry low-NOx premix burners 20-90
Existing CCGT without
or water and steam injection (split view industry existing plants:
supplementary firing
or SCR if required space 80-120)
Dry low-NOx premix burners
New CCGT with supplementary
and low-NOx burners for the 20-50
firing
boiler part or SCR or SNCR
Dry low-NOx premix burners
or water and steam injection 20-90
Existing CCGT with
and low-NOx burners for the (split view industry existing plants:
supplementary firing
boiler part or SCR if required 80-140)
space in the HRSG or SNCR
Low NOx burners or SCR or 50 - 100 (3% O2)
Industrial boiler; fuel: gas
SNCR (industry split view: 50-120)
Existing Gas-Turbines
Water and steam injection or 50-90
Fuel: natural gas
SCR (industry split view: 80-120)
Water and steam injection or
Fuel: diesel oil or process gas SCR
New Gas-Turbines
Dry low-NOx premix burner or
Fuel: natural gas SCR 20-50
Wet controls
Fuel: diesel oil or process gas
SCR

1
The BAT associated emission levels are based on a daily average, standard conditions and represents a typical
load situation. For peak load, start up and shut down periods, as well as for operational problems of the flue gas
cleaning systems, short-term peak values, which could be higher, have to be regarded.
gas of 3 % in the case of liquid and gaseous fuels, 6 % in the case of solid fuels and 15 % in the case
of gas turbines.
Dust is emitted from the combustion process, especially from the use of heavy fuel oil, coal and solid
biomass. Dust emissions of solid fuel combustion are higher than dust emissions from fuel oil
combustion. Because In such large combustion, BC content of dust is very low due to very high
combustion efficiency generally achieved. BC is formed during incomplete combustion and is, it is
mainly associated to particles with a diameter less than 1 µm. In such large combustion installations,
BC concentrations in dust can increase during start-up and shut-down periods in which incomplete
combustion conditions can occur. A smooth, continuous and optimised combustion reduces dust
(including PM10, PM2.5 and BC) emissions as described in chapter 6.4. Only reduction techniques able
to remove fine particles have a significant efficiency on BC emissions. In such large combustion
installations, BC concentrations of dust increase during start-up periods. BC content of dust is then
very low due to very high combustion efficiency. The proven technologies for dust removal in power
plants are fabric filters and electrostatic precipitators (ESPs) [6].
Electrostatic precipitators (ESPs) are the dust emissions control technology, which is most widely
used in coal-fired power generating facilities [5]. They remove particles from a flowing gas using
electrical forces. The particles are given an electrical charge by forcing them to pass through a corona,
a region in which gaseous ions flow. The electrical field that forces the charged particles to the walls
comes from electrodes maintained at high voltage in the centre of the flow lane [7].
These control devices remove dust, including particulate matter less than or equal to 10 and 2.5
micrometers and hazardous air pollutants that are in particulate form, such as most met al oxides [7].
Electrostatic precipitators are used in both solid and liquid fired combustion plants and are available
for small and large-scale combustion plants [1]. ESPs provide high dust and fine particulate removal
efficiency (and consequently BC which is a component of fine particulates if present).The efficiency of
ESPs is described in chapter 6.5.
Fabric filters (Baghouses), are widely used worldwide for removing particles. A fabric filter unit
consists of one or more isolated compartments containing rows of fabric bags in the form of round,
flat, or shaped tubes, or pleated cartridges. Particle-laden gas passes up along the surface of the bags
then radially through the fabric. Particles are retained on the upstream face of the bags, and the
cleaned gas stream is vented to the atmosphere [8]. This control devices remove dust, including
particulate matter less than or equal to 10 and 2.5 micrometers and hazardous air pollutants that are
in particulate form, such as most metal oxides [9]. The choice between ESP and fabric filtration
generally depends on coal type, plant size, and boiler type and configuration [ 5]. Fabric filters provide
high dust and fine particulate removal efficiency (and consequently BC which a component of fine
particulates if present). The efficiency of fabric filters is described in chapter 6.5.
Wet scrubbers, are air pollution control devices that remove dust and acid gases from waste gas
streams of stationary point sources provided that the PM level is already within the right range to
guarantee safe operation of the scrubber (if not another PM control technology is required upstream
the FGD). The low capital cost of wet scrubbers compared to that for ESPs and baghouses makes
them potentially attractive for industrial scale use, though this may be offset by a relatively high
pressure drop and operating costs [3]. The pollutants are removed primarily through the absorption of

the pollutant onto droplets of liquid. The liquid containing the pollutant is then collected for disposal.
There are numerous types of wet scrubbers, which remove both acid gas and dust.
BAT for the removal of dust
Combustion of coal and lignite

For dust removal of off-gases from coal- and lignite-fired new and existing combustion plants, BAT is
3
the use of an ESP or a FF, where a FF normally achieves emission below 5 mg/m . Cyclones and
mechanical collectors alone are not BAT, but they can be used as a pre-cleaning stage. BAT
associated emission levels for dust are lower for combustion plants over 100 MWth, especially over
300MWth because the wet FGD techniques which are already a part of the BAT conclusion for
desulphurisation also reduce dust [10].

For dust removal from off-gases from biomass- and peat-fired new and existing combustion plants,
BAT is the use of FF or an ESP. When using low sulphur fuels such as biomass, the potential for
reduction performance of ESPs is reduced with low flue-gas sulphur dioxide concentrations. In this
3
context, the FF, which leads to dust emissions around 5 mg/Nm , is the preferred technical option to
reduce dust emissions. Cyclones and mechanical collectors alone are not BAT, but they can be used
as a pre-cleaning stage [10].

For dust removal from off-gases from new and existing liquid fuel-fired combustion plants, BAT is the
use of an ESP or a FF. Cyclones and mechanical collectors alone are not BAT, but they can be used
as a pre-cleaning stage. BAT associated emission levels for dust are lower for combustion plants over
300 MWth because the FGD technique that is part of the BAT conclusion for desulphurisation also
reduces dust [10].
Table 3: emission sources and selected BAT dust control measures with associated emission
levels in combustion installation (PM is for primary measures)
Emission source Combination of control Dust emission level associated

1 3
boilers 50 - 100 MWth
< 5 - 20 (new)
Boiler; (split view industry: new plants: 10-50)

Fuel: coal and lignite ESP or FF 5-30 (existing)
(split view industry: existing plants: 20-
100)
Circulating FBC,
Fuel: coal, lignite ESP or FF

< 5 - 20 (new)
Circulating FBC; Bubbling FBC ESP or FF
< 5 - 20 (new)
Boiler, 5 - 30 (existing)
Fuel: oil ESP or FF
(split view industry: new and existing
plants: 10-50 ESP)
Boilers 100 – 300 MWth

< 5–20 (new)
Boiler; 5-25 (existing)

ESP or FF in combination with
Fuel: coal and lignite FGD (split view industry: new plants: 10-30;
existing plants: 10-100 ESP/FF; 10-50
in combination with wet FGD)
< 5–20 (new)
Circulating FBC, 5-25 (existing)

Fuel: coal, lignite ESP or FF (split view: new plants: 10-30;
existing plants: 10-100 ESP/FF; 10-50
in combination with wet FGD)
< 5 - 20 (new)
Circulating FBC; Bubbling FBC; ESP or FF
< 5 - 20 (new)
Boiler, ESP or FF in combination with 5 - 25 (existing) (split view industry:
Fuel: oil FGD new plants: 5-30, existing plants: 5-
50)
Boilers >300 MWth
< 5 - 10 (new)
Boiler; 10 –20 (existing)
ESP or FF in combination with
Fuel: coal and lignite FGD (split view industry: new plants: 10-30,
existing plants: 10-100; 10-50 comb.
wet FGD)
< 5 –20 (new)
Circulating FBC; 5-20 (existing)
Fuel: coal, lignite ESP or FF
(split view industry: new plants: 10-30,
existing plants: 10-100; 10-50 comb.
wet FGD)
< 5 - 20 (new)
Circulating FBC; Bubbling FBC ESP or FF
< 5 - 10 (new)
Boiler; ESP or FF in combination with 5 - 20 (existing)
Fuel: oil FGD
(split view industry: new plants: 5-30,
existing plants: 5-50)
1
gas of 3 % in the case of liquid and gaseous fuels, 6 % in the case of solid fuels.

7.3.4 Cost data for emission reduction techniques
7.3.4.1 Cost data for NOx emission reductions
Table 4: indicative costs of NOx emissions abatement techniques for boiler plants (1999 Euros,
Environment Agency)
Indicative capital Indicative

Typically achievable Process capacity cost € /kWel
Control options operating cost€
emission reduction (MWel) /kWh
1 2
SCR 80-90% Various 30-70 11-14 €/kWel/a 2
SNCR 30-50% Various 14 0.0011
Reburning 50-75% Various 42 0.0011
Flue gas
15-45% Various 14 0.00014
recirculation
Low NOx Burner 30-50% Various 14 0
1
It should be noted that the design of SCR is highly site-specific and this makes definition of capital
cost difficult
2
J. Theloke, B. Calaminus, F. Dünnebeil, R. Friedrich, H. Helms, A. Kuhn, U. Lambrecht, D. Nicklaß,
T. Pregger, S. Reis, S. Wenzel (2007): Maßnahmen zur Einhaltung der Emissionshöchstmengen der
NEC Richtlinie, Umweltbundesamt, Texte 36/07, 498 pp. (cost data on p. 162)
7.3.4.2 Cost data for SOx emission reductions
Table 5 shows the indicative costs ranges for the sulphur abatement technologies described above.
However, when applying these technologies to individual cases, it should be noted that investment
costs of emission reduction measures will depend among other things on the particular technologies
used, the required control systems, the plant size, the extent of the required reduction and the
timescale of planned maintenance cycles. Operation and maintenance costs for SO 2 scrubbers for
boiler plants increase with increasing sulphur content since more reagent is required to treat the same
volume of gas [11].
Table 5: indicative costs of SO2 emissions abatement techniques for boiler plants (2001 Euros,
EPA)
Annual Cost Cost per ton of

Process
Capital cost O&M Cost Pollutant
Control option capacity €/kW Removed
€ /kW €/kW
MWth
€/ton
Wet scrubber >400 104 - 262 2-8 21 -52 210 -523
Wet scrubber <400 262 - 1572 8- 21 52 - 210 523 - 5230
Dry Scrubber >200 41- 157 4- 11 21 - 52 157 - 314
Dry Scrubber <200 157 - 1572 11 - 314 52 - 523 523 - 4190

7.3.4.3 Cost data for dust emission reductions
Table 6: indicative costs of dust emissions abatement techniques for boiler plants (1999 Euros,
Environment Agency)
Indicative Indicative
Typically
Control options achievable Process capacity capital cost Operating cost
emission reduction
€/kW €/kWh
Reduction to below
ESP 3 various 35 0.00042
25 mg/m
Reduction to below
Fabric filters 3 various 14 0.0015
25 mg/m

[1] Technical background documents for the actualisation and assessment of UN/ECE protocols
related to the abatement of the Transboundary Transport of nitrogen oxides from stationary sources,
DFIU, 1999
[2] Environment Agency, 2002: V2. 03 27.07.05, IPPC Sector Guidance Note Combustion Activities
[3] European Commission. 2006: Integrated Pollution Prevention and Control (IPPC) Reference
Document on Best Available Techniques for Large Combustion Plants
[4] Multipollutant emission control technology options for coal fired power plants, US EPA 2005.
[5] http://www.iea-coal.org.uk/site/ieacoal/home
[6] IFC 2007. International Finance Corporation (World Bank Group): Environmental, Health, and
Safety Guidelines for Thermal Power Plants
[7] US Environmental Protection Agency (US EPA). EPA-452/F-03-028, Air Pollution Control
Technology Fact Sheet- Dry Electrostatic Precipitator (ESP)-Wire-Plate Type
[8] US Environmental Protection Agency (US EPA). EPA-452/B-02-001, Section 6, Chapter 2, Wet
Scrubbers for Particulate Matter
[9] US Environmental Protection Agency (US EPA). EPA-452/F-03-026.025.024, Air Pollution Control
Technology Fact Sheet-Fabric Filters
[10] UNECE 2006. Draft background document: Assessment of technological developments: Best
Available Techniques (BAT) and limit values. Submitted to the Task Force on Heavy Metals of UNECE
CLTRAP
[11] US Environmental Protection Agency (US EPA). EPA-452/F-03-034, Air Pollution Control
Technology Fact Sheet-Flue Gas Desulphurisation-Wet, Spray Dry, and Dry Scrubber


7.4 Mineral Oil and Gas Refineries for SO2, NOx dust (including PM10,
PM2.5 and balck black carbon) emissions
7.4.1 Coverage
The section covers emissions from combustion processes in refineries burning non-commercial fuels
or a mixture of commercial and non-commercial fuels, Fluidised Catalytic Cracking (FCC) units,
Sulphur Recovery Units (SRU) and flares.
Refinery fuels are highly variable in nature and comprise both liquid and gaseous streams often used
in conjunction. A significant part of the fuel used for process heaters is provided by refinery gas.
Various processes contribute a large variety of compounds to the refinery gas, resulting in varying
emissions. Other fuels in use in mineral oil refineries are natural gas, petroleum coke, heavy fuel oil, or
other gaseous or liquid residues originating from atmospheric and vacuum distillation, fluid catalytic
cracking (FCC) and thermal catalytic cracking (TCC). Refinery processes such as FCC may involve
combustion of coke laid down on the catalyst and CO as well as supplementary fuel for steam raising.
Use of petroleum coke as a gasification feedstock occurs but is not very common
Many refinery units discharge through a common stack. The emissions from refineries associated with
the key processes in this chapter are NOX, SOX and dust (including PM10, PM2.5 and black carbon
(BC)). BC is an inseparable part of fine particles. Its emissions from combustion units are low as these
emissions are linked to may occur during incomplete combustion not frequent in this activity.
Incomplete combustion may occurencountered during start-up, shut-down and soot-blowing periods
and if the installation is not operated in optimised combustion condition . Flares can be a source of BC
emissions.
A work is still progress to revise the BREF document on refineries dated 2003 [3], at the Institute for
Prospective Technological Studies (IPTS) in Seville. The 2003 document is the main reference for
most of the BAT AELs presented in this chapter.

In the following, the focus is on emissions from processes used in the production of refined products
from crude oil. These include process heaters and boilers, power generation and recovery, catalytic
cracking, sulphur recovery and flare systems.
Process heaters and boilers

In most refining processes it is necessary to apply heat to raise the temperature of the feedstock to a
required level. Fired process heaters and boilers are the main heat producers. Process heaters are
installed at the atmospheric distillation, before the vacuum distillation, before the FCC units and before
the hydrotreatment units. Refineries can have many process heaters, with different feedstock [1].
Gas turbine installations are used for the transformation of thermal energy into mechanical energy.
They use a steady flow of a gas (mostly air), compressed and fired with (sometimes non -commercial)
gaseous or liquid fuel. The energy in the turbine exhaust gas can be recovered in a heat recovery
section downstream of the gas turbine. This heat recovery section comprises of a steam boiler or a
process heater which can be equipped with additional fuel supply. Steam turbines are used to
transform the steam pressure to power. Combined cycle processes combine the gas and steam
turbines processes to produce power at higher efficiency than reached with open-cycle turbines.
(Fluid) Catalytic cracking (FCC) is the most widely used conversion process for upgrading heavier
hydrocarbons into more valuable lower boiling hydrocarbons. It uses heat and a catalyst to break
larger hydrocarbon molecules into smaller, lighter molecules. A catalytic cracking unit is usually part of
a processing complex that includes a gas plant, amine treating of the light (incl. C3/C4) gases and
treatment of various product streams [3].

Sulphur Recovery Units (SRU) typically comprise a Claus unit and a tail gas unit. They recover
elemental sulphur from the H 2S recovered in the acid gas removal section. The tail gas treatment
section is designed to increase the overall sulphur recovery. They work by partial combustion of the
hydrogen sulphide-rich gas stream and then reacting the resulting sulphur dioxide and unburned
hydrogen sulphide in the presence of a catalyst to produce elemental sulphur [3].
Flare-Gas-System consists at least of a flare knock-out drum and a flare stack as well as additional
supporting equipment and is connected through a flare gas pipeline grid to many refinery processes.
The overall goal of a flare gas system is to assure or support a pressure release of a process
equipment (e.g. columns, vessels) if necessary and to keep the refinery processes in a safe condition
even in an emergency case. During shut-down or start-up periods of units, e.g. before and after
maintenance activities, the flare gas system has to collect off-gases for safe discharge. Flare systems
are sources of SO2, NOx and dust (including BC) emissions.

7.4.3.1 SO2
The release of sulphur dioxides is directly linked to the sulphur content of the refinery fuel gas and fuel
oils used for combustion units. Heavy fuel oil residues normally contain significant proportions of
sulphur and nitrogen depending mainly on their source and the crude oil [2].
Various flue gas desulphurisation techniques exist with SO 2 removal efficiencies ranging from 50 to 95
to 98 %. SO2 is removed in general from the flue gas by means of wet scrubbers (lime/limestone,
Wellman-Lord, seawater, wet gas sulphuric acid process WSA), spray dry scrubbers, application of
sorbent injection and regenerative processes. By using wet lime/limestone reduction rates from 90 to
98% are achievable. With additive injection and spray dry scrubbers reduction rates above 92% are
achievable. However, these efficiency figures are dependent on input concentrations, sizes of units
and their specific application.
Improvement of the energy efficiency by enhancing heat integration and recovery throughout the
refinery, applying energy conservation techniques and optimising the energy production/consumption
is considered BAT [3].
The use of low sulphur content for the overall refinery liquid fuel pool achieved for example, by
hydrodesulphurisation, is considered to be BAT and FGD for large boilers/furnaces where it is cost-
effective. Fuel switching is also an option.
For catalytic cracking, SO2 emission reduction by using Sulphur Reducing Additives (SRA), FGD of
the regenerator gas with 95 – 99 % efficiency (emission target depends on uncontrolled level) is
considered BAT if economically viable [3].
Wet scrubbing (for example Wellman Lord scrubbing) is one option for FGD, a suitably well designed
process will normally provide an effective removal efficiency of both SO 2/SO3 and particulates. With
the inclusion of an extra treatment tower, to oxidise the NO to NO 2, NOx can also be removed partially
[3].
Before elemental sulphur can be recovered in the SRU, the fuel gases (primarily methane and ethane)
need to be separated from the hydrogen sulphide. This is typically accomplished by dissolving the
hydrogen sulphide in a chemical solvent (absorption). Solvents most commonly used are amines [3].
For sulphur recovery units (SRU), it is BAT to apply a staged SRU, including tail gas treatment with
the recovery efficiency given below (based on acid gas feed to the SRU), the range depends on cost
effectiveness considerations [3].

Table 1: emission sources and selected BAT SOx control measures with associated emission
levels in mineral oil refineries
Emission source Combination of control SOx emission level associated

1 3
measures with BAT (mg/Nm )[3]
Fuel type: refinery fuel gas
3,
5 –20
Heaters, Boilers, Use of sulphur removal
techniques for fuel gas
Gas turbines
And use of monitoring when using fuel gas by cleaning
refinery fuel gas
Fuel type: liquid fuel
Combination of:
Heaters, Boilers 50 – 850
Low S fuels
for the total refinery liquid fuel
Use of FGD techniques (where pool
feasible and cost-effective)
Catalytic cracking
Suitable combination of:
Hydrotreatment of the feedstock
if it is economically and
technically viable
Catalytic cracking 10-350
Sulphur Reducing Additives
(SRA)
FGD of the regenerator gas if
economically viable
Sulphur Recovery Units (SRU)
2 New plants 99.5-99.9%

Sulphur recovery rate
Existing plants 98.5-99.5%
1
2
The sulphur recovery rate is the percentage of the imported H2S converted to elemental sulphur as a yearly
average
3
As values are expressed on a dry basis, this value has to be adjusted for hydrocarbon-hydrogen mixtures. The
upper value range thus increases in proportion to the fuel hydrogen content having a value of 35 at a fuel H 2
concentration of 50% v.
Oxygen reference: dry basis, 3% for combustion (also for gas turbines (if expressed at 15%, the range for gas
turbine is 7 - 17))
7.4.3.2 NOx
Refinery NOX emissions primarily originate from combustion units and catalytic cracking. Besides the
relevance of the fuel type, NOx emissions depend on fuel nitrogen content (for liquid fuels) or
hydrogen content and C3+ content (for gaseous fuels), burners and heaters design, and operating
conditions [4].
In general, the reduction of the fuel consumption and the replacement of existing burners with low -
NOx burners during major scheduled shutdowns is considered to be BAT as far as is possible with
respect to the existing process engineering design.

For heaters and boilers burning gaseous fuel an application of a suitable combination of the following
3
primary and secondary measures allowing to achieve emissions levels from 20 to 150 mg/Nm is
considered to be BAT [3]:
high thermal efficiency furnace/boiler designs with good control systems
jowlow-NOx burners technique
flue gas circulation in boilers
SCR or SNCR
For heaters and boilers burning combinations of gas and liquid fuel (liquid fuel as majority fuel) an
application of a suitable combination of the following primary and secondary measures allowing to
3
achieve emissions levels from 55 to 300 mg/Nm is considered to be BAT [3]:
fuel with low nitrogen content
low-NOx burners technique
flue gas circulation in boilers
reburning technique
SCR or SNCR to liquid fuels heavier than gasoil type (if technically and economically feasible)
For gas turbines an application of a suitable combination of the following primary and secondary
3
measures allowing to achieve emissions levels from 20-75 mg/Nm is considered to be BAT [3]:
diluent injection
dry low NOx combustors
SCR (if technically and economically feasible)

Table 2: emission sources and selected BAT NOx control measures with associated emission
NOx emission level

Emission 1
One or combination of control measures associated with BAT
source 3
(mg/Nm ) [3]
Fuel type: refinery fuel gas
- high thermal efficiency designs with good control
systems 2
20 – 150
Heaters, Boilers - low-NOx burners technique
- flue gas circulation in boilers
- SCR or SNCR (if technically and economically feasible)
- diluent injection 20 – 75
Gas turbines
burning either - dry low NOx combustors (lower levels for natural
gas or light liquid - SCR (where technically and economically applicable) gas and higher levels
fuels for small gas turbines
and RFG)
Fuel type: heavy liquid fuel firing (majority fuel)
- liquid fuel with low nitrogen content
2
- low-NOx burners technique 55 – 300
Heaters, Boilers - flue gas circulation in boilers
- SCR or SNCR to liquid fuels heavier than gasoil type
(where technically and economically applicable)
Catalytic cracking
CO-furnace/boiler for partial oxidation conditions 100-300
Catalytic for full combustion plants 300-600

cracking
Combination of (if economically viable): modification of 40-150
the design and operation of regenerator, SCR, SNCR
1
2
in the EU-BREFof 2003, several split views exist about BAT AELs.
Oxygen reference: dry basis 3% for combustion, 15 % for gas turbines

The main emission sources of dust in refining are process heaters and boilers firing liquid heavy fuel
oil, catalytic cracker regenerators, coke plants, incinerators, decoking and soot blowing of heaters and
the flare [3].
The emission levels of dust depend on various parameters such as fuel type, burner design, and
oxygen concentration at the outlet of the radiant section and can vary widely.
The dust emissions from furnace and boilers burning heavy fuel oil consist of a mix of ash, soot and
BC. Mineral matter is a natural component of crude oil and becomes ash during combustion of heavier
fuel oils. Soot and BC result from imperfections in the combustion process. BC content of dust is low
in continuous processes with optimised combustion conditions but can be higher during start-up and
shut-down periods in which imcomplete combustion condition can occur.
The size of the particulate matter from heaters and boilers burning heavy fuel oil is in the order of 1
m. Particulate matter removal techniques mainly used are ESPs. An application of a suitable
combination of the following techniques is considered to be BAT for the reduction of dust [3]:
Reduction of the fuel consumption
Maximizing the use of gas and low ash content liquid fuels
Improved atomisation on the liquid fuels
The use of ESP or filters in the flue gas of heaters and boilers when burning heavy liquid fuel s
[3] if technically and economically feasible.
Table 3: Emission sources and selected BAT dust control measures with associated emission
Dust emission
Emission level associated
One or combination of control measures 1
source with BAT
3
(mg/Nm )
Fuel type: heavy liquid fuel (majority fuel)
By a combination of:
- Reduction of the fuel consumption 5 – 20 [3]
Heaters,
boilers - Maximizing the use of gas and low ash content liquid fuels (split view industry:
- Steam atomisation on the liquid fuels 5-50)
- Use of ESP
By a suitable combination of:
FCC process integrated measures,

2
10-40 [5]
regenerators ESP,
third stage cyclones, scrubbers
1
² If technical difficulties in upgrading the existing ESPs, the upper range can be difficult to reach. In those cases
50 is seen as a more achievable value [3].
Oxygen reference: dry basis, 3% for combustion, 15 % for gas turbines.

BAT for flare systems:

Flare systems can be equipped with adequate monitoring and control systems necessary to operate
smokelessly and should be observed at all times under non emergency conditions to avoid emissions.
Techniques to be applied to flares that may reduce emissions (including BC) [3] are:
the pilot burners give more reliable ignition to the vent gases because they are not affected by
the wind
steam injection in flaring stacks can reduce particulate matter emissions
coke formation in flare tips should be prevented
surplus refinery gas should be flared, not vented. Knock-out pots to remove liquids should be
provided, and with appropriate seals and liquid disposal system to prevent entrainment of
liquids into the combustion zone. Water streams from seal drums should be routed to the sour
water system
flare-gas recovery systems have been developed due to environmental and economic
considerations. The flare gas is captured and compressed for other uses. Usually recovered
flare gas is treated and routed to the refinery fuel gas system. Depending upon flare gas
composition, recovered gas may have other uses. Reductions of flaring to ratios of 0.08 - 0.12
% of production in one natural gas plant in Norway have been reported. Flare gas recovery is
not cost effective if the flow of gas to flaring is reduced by other measures.

Emerging techniques in the field of SO2 emission reduction are SO2 capture from flue gas and
subsequent conversion into liquid sulphur as well as biological H 2S removal [3].
Integrated gasification combined cycle (IGCC) is a technique for producing steam, hydrogen and
electric energy from a variety of low-grade fuel types. The gasified solid fuel is burned in the
combustion chamber of the gas turbine. Emissions from IGCC are low. The technology also exists for
heavy oil residue. However, this process is not yet fully commercialized for refeneries, a number of
demonstration units, mainly around 250 MWe size are being operated in Europe and the USA.

[1] O. Rentz, D. Oertel: Process Furnaces, SNAP Code 01 03 06, In: Atmospheric Emission Inventory
Guidebook, CD-Rom, 1996
[2] Environment Agency: Guidance for the gasification, liquefaction and refining sector, 2003
[3] European commission: Reference Document on Best Available Techniques for Mineral Oil and Gas
Refineries, Integrated Pollution Prevention and Control (IPPC), February 2003
[4] O. Rentz, S. Nunge, M. Laforsch, T. Holtmann: Technical Background Document for the
Actualisation and Assessment of UN/ECE Protocols related to the Abatement of the Transboundary
Transport of Nitrogen Oxides from Stationary Sources, Task Force on the Assessment of Abatement
Options/Techniques for Nitrogen Oxides from Stationary Sources, Karlsruhe, September 1999
[5] J. Schacht, J. Courtheyn: ESP units realise major dust emission reduction at Total Refinery
Antwerp. Total Refinery Antwerp, presented at Dustconf 2007
[6] Concawe Report 4/09 “Refining BREF review – Air Emissions” Prepared by the CONCAWE Air
Quality Management Group’s Special Task Force on Integrated Pollution Prevention and Control
(AQ/STF-70), 2009


7.5 Mineral oil and gas refineries for VOC emissions
7.5.1 Coverage
This chapter covers activities originating VOC emissions in the oil refineries: fugitive emissions, flare
system, storage tanks, and oil separators. Fugitive VOC emission sources (such as leakages from
flanges, pumps or any pieces of equipment) and losses from the storage facilities of liquid products
may contribute more than 50 % to the total VOC emissions. VOC emissions also occur from
processes linked to combustion and from flares but these are lower emitters of VOCs in refineries.
The refinery petrol dispatch station is covered by chapter 7.20.

Sources of VOC emissions considered are as follows:
Fugitive emissions:
Fugitive VOC emissions are released from leaking pressurised equipment components on process
units, such as valves, flanges and connectors, opened lines and sampling systems containing volatile
liquids or gases. Volatile products are defined in CEN 15446 [9] and reference [10] as all products of
which at least 20% by weight has a vapour pressure higher than 0.3 kPa at 20C.
The quantity of VOC emissions from sealing elements, depends on:
size, type and material of the seal,
state of maintenance, age of the equipment,
pressure, temperature, and physical condition of the product. Emissions are larger at those
refineries that are processing light products (fuel producing refineries).
valves represent 50-60 % of fugitive emissions [1]. A major portion of fugitive emissions comes
from only a small portion of sources (less than 1 % of valves in gas / vapour service may
account for more than 70% of the fugitive emissions of a refinery).
The flare systems:

Flares are used for safety and environmental control of discharges of undesired or excess
combustibles and for surges of gases in emergency situation or upsets [1]. The VOC emissions from
flaring itself are a small proportion of the total refinery VOC emissions. Fugitive emissions, however,
can result from leaking equipment components in the flare gas collection system.
The oil water separators:

Waste water treatment systems employed in refineries include neutralisers, oil/water separators,
settling chambers, clarifiers, dissolved air flotation systems and activated sludge ponds. If
contaminated by oil, the waste water from a refinery is passed to a multi-stage water purification via an
oil separator or via flocculation.
Emissions from sewage systems and oil separators primarily result from evaporation of NMVOC from
liquid surfaces open to the atmosphere. Direct sources include processes that use water for washing
(e. g. desalter), sour water stripping and also steam used in jet eductors to produce vacuum. Indirect
sources include leaks from heat exchangers, condensers and pumps.
Sources of contamination with hydrocarbons are [4]:
desalters: 40 %
storage tanks: 20 %
slop systems: 15 %
other processes: 25 %

Crude oil and volatile product storages:

A significant proportion of the VOC emissions from refineries may arise from storage tanks for crude
oil and volatile products in case of no use of BAT. Those products may be stored in different types of
storage tanks according to the physical and chemical properties, such as fixed roof tanks, external
floating roof tanks or internal floating roof tanks. Fixed roof tanks can only be used for petroleum
products with very low vapour pressure.
7.5.3 BAT, associated emission levels (AEL)

BAT for reducing VOC emissions are as follows [1] and [2]:
Fugitive emissions:
quantifying VOC emission source in order to identify the main emitters in each specific case,
executing leak detection and repair programme (LDAR) campaigns or equivalent. A good LDAR
includes the determination of the type of measurement frequency, type of components to be
checked, type of compound lines, what leaks should be repaired and how fast action should be
taken,
using a maintenance drain out system,
selecting and using low leakage valves such as graphite packed valves or equivalent for lines
containing product with high vapour pressure,
using low leak pumps (e.g. seal less designs, double seals, with gas seals or good mechanical
seals) on lines containing product with high vapour pressure,
blinding, plugging or capping open ended vents and drain vents,
routing relief valves with high potential VOC emissions to flare,
routing compressor vents with high potential for VOC emissions back to process and when not
possible to refinery flare for destruction,
using totally closed loop in all routine samplers that potentially may generate VOC emissions,
minimizing flaring.
A LDAR programme is established according to the following principles [3]:

1 the definition of what constitutes a leak and fixation of corresponding thresholds,
2 the fixation of the frequency of inspections,
3 the listing and identification of components included,
4 the procedures concerning repair of leaking components depending on the leak category.
Equipment tightening can be made with equipment in operation (except with remote control valves
(e.g. tightening bolts to eliminate leaks from valves stems or flanges, installing tightening caps on
open ends…). , etc).
Maintenance with equipment dismantling or exchange can only be implemented during plant
shutdowns with circuit insulation and degassing. This implies that implementing this type of
maintenance with the sole objective of reducing fugitive emissions would lead to unacceptable costs.
Maintenance on the equipment can consist in removing some parts or replacing the equipment with a
new one of the same technology (named basic maintenance in this document). A complete change of
equipment such as valves with valves of the newest not leaking technology can also be operated (not
considered in this document).

Water treatment plant [1]:

covering separators, basins and inlet bays and by routing off gases in the waste water treatment
plant. Implementation of some of these techniques may compromise efficient operation of the
waste water treatment plant or cause safety concerns if they are not properly designed and
managed. For these reasons, this technique may have some technical problems when
retrofitted.
Storage and handling [1] and [2]:

ensure that the liquids and gases stored are in appropriate tanks or vessels based upon the true
vapour pressure of the stored materials,
use high efficiency seals in floating roof tanks (example provided in reference [1] indicates an
incremental reduction potential for changing from a vapour mounted primary seal to a liquid
mounted seal was 84%),
bund all stored chemicals, with separate bunding for incompatibles,
apply emission reduction measures during tank cleaning,
apply concept of good house keeping and environmental management,
minimise the number of tanks and volume by suitable combination of application of in line
blending, integration of processing units, these techniques being much easier to apply on new
facilities, e.g. by vapour balance lines that transfer the displaced vapour from the container
being filled to the one being emptied. Incompatibility of tank vapours and applicability to external
floating roofs tank are some examples of restrictions of application. Applicability needs to reflect
economics, the type and size of vessel to be used (e.g. tank, truck, railcar, ship), type of
hydrocarbon fraction and frequency of use of the tank. Because this technique is related to the
next one, both should be evaluated together when implementing on a specific site.
apply vapour recovery (not applicable to non-volatile products) on tanks, vehicles, ships etc. in
stationary use and during loading/unloading. Achieved emission levels are very dependent on
the application, but recoveries of 95 - >99 % are considered BAT. If VRUs are not considered
appropriate for certain streams, vapour destruction units are considered BAT. Properties of
streams, such as type of substance, compatibility of substances or quantity need to be
considered in the applicability of this BAT. Applicability needs to reflect economics, the type and
size of vessel to be used (e.g. tank, truck, railcar, ship), type of hydrocarbon fraction and
frequency of use of the tank. Because this technique is related to the above one, both should be
evaluated together when implementing on a specific site.
reduce the risk of soil contamination by the implementation of an inspection maintenance
programme which can include good house keeping measures, double bottom tanks, impervious
liners…
install self sealing hose connections or implement line draining procedures,
some other best practices.
External floating roofs and internal floating roofs can have the following emission reduction efficiency:
The BAT associated emission reduction level associated to an external floating roof for a large tank is
at least 97 % (compared to a fixed roof tank without measures), which can be achieved when over at
least 95 % of the circumference the gap between the roof and the wall is less than 3.2 mm and the
seals are liquid mounted, mechanical shoe seals. By installing liquid mounted primary seals and rim
mounted secondary seals, a reduction in air emissions of up to 99.5 % (compared to a fixed roof tank
without measures) can be achieved [2].
The achievable emission reduction for a large tank using an internal floating roof is at least 97 %
(compared to a fixed roof tank without measures), which can be achieved when over at least 95 % of
the circumference of the gap between the roof and wall is less than 3.2 mm and the seals are liquid
mounted, mechanical shoe seals. By applying liquid mounted primary seals and rim mounted
secondary seals, some further improvement in emission reductions can be achieved. However, the
smaller the tank and the smaller the numbers of turnovers are, the less effective the floating roof is.

However, measurements of diffuse sources (e.g. tanks) can only be made over short periods and
extrapolation to provide annual estimates of emissions introduces significant errors due to the
temporal variations in emissions from these types of sources.
Table 1: associated Emission Levels with BAT to reduce VOC emissions from storage
Emission sources Combination of BAT BAT Associated Emissions
Levels for VOCs
Internal floating roof
Storage tanks of volatile External floating roof 97 to 99.5 % compared to a
products Other tank designs and appropriate fixed roof tank without
colours measure*
* If the efficiency cannot be reached because of the specific characteristics of a storage tank (such as small
throughput, small diameter), best available primary and secondary seals have to used.
Table 2: associated Emission Levels with BAT to reduce VOC emissions in refinery loading and
unloading operations
Emission source BAT and reduction efficiency BAT associated
emission levels*
3
kg VOC/m /kPa
[1], [6]
Road tanker filling, bottom or 0.0228 x 0.05 to
top loading and vapour 0.0228 x 0.01
balancing during previous off
loading and VRU
Rail tanker, top loading and 0.0108 x 0.05 to
VRU VRU with 95 to 99 % efficiency [1] 0.0108 x 0.01
Marine tanker, typical cargo 0.004 x 0.05 to
tank condition 0.004 x 0.01
Barge – typical cargo tank 0.007x 0.05 to
conditions 0.007 x 0.01
*Not available in reference [1] but calculated with reference [6].
kPa: True vapour of the volatile product.

The EGTEI synopsis sheet [7] on VOC emissions in refineries provides costs of VOC emission
reduction techniques.
Cost of a LDAR programme depends on the thresholds defining what constitutes a leak. Reference [1]
provides operating costs ranging from 0.04 to 0.08 M€/year for a 10000 ppm programme and 0.8
M€/year for a 100 to 500 ppm.
7.5.5 References used for chapter 7.5

[1] European Commission - Reference document on best available techniques for mineral oil and gas
refineries - BREF – February 2003 – European commission – Available at: http://eipccb.jrc.es
[2] European Commission - reference document on BAT on emissions from storage – February
2003July 2006 – Available at: http://eipccb.jrc.es
[3] EGTEI - background document on the organic chemical industry - 2003

[4] VAN DER REST A. and others: Best available techniques to reduce emissions from refineries -
CONCAWE report n°BAT/II – air – February 1999
[5] GOODSELL P.: Information mail to CITEPA of September 8, 2003. Provided in reference [3]
[6] CONCAWE - Air pollutant emission estimation methods for E-PRTR reporting by refineries - Report
n°1/2009 (Amending report 2007)
[7] EGTEI synopsis sheets on NMVOC from refineries – October 2005
[8] EPA - Emission factor documentation for AP42 section 7.1 - Organic liquid storage tanks - Final
report - September 2006
[9] EN15446:2008 Fugitive and diffuse emissions of common concern to industry sectors -
Measurement of fugitive emission of vapours generating from equipment and piping leaks
[10] EPA - Protocol for equipment leak - Emission estimates EPA 453-95-017 – 1995
[11] Edda Hoffmann, UBA Germany: comments on the first version of the guidance document


7.6 Coke oven furnaces
7.6.1 Coverage
This section deals with emissions originating from coke oven furnaces in iron and steel production.
The further use of coke or coke oven gases is not regarded here, for information see section “Iron and
Steel Production”.

Within the production of primary iron and steel, the blast furnace (cf. Refer to section “Iron and Steel
Production”) is the main operational unit. Coke is basically used as a reducing agent in a blast furnace
due to its physical and chemical characteristics. It is produced from coal in a coke oven via dry
distillation.
Coke oven plant: Coke is produced via heating of coal mixtures in absence of oxygen. The coke
oven is a chamber made up of heat resistant bricks. A heating wall consists of heating flues with
nozzles for fuel supply and with air intakes. In general, cleaned coke oven gas is used as a fuel as
well as other gases such as blast furnace gas. The coke is afterwards used mainly as a reducing
agent in blast furnaces.
Due to high costs of coke, replacement by pulverized coal, fuel oil, plastics etc. may replace it as
reducing agents in the blast furnace route [2]. This reduction in coke consumption also helps to
reduce total emissions from coke production. Several 'direct' and 'smelting reduction' processes have
been developed for primary iron production without the use of coke (for example Corex).
7.6.3.1 SO2
In general emissions of SO2 can be minimised by reducing the sulphur content of the coal.
During the coking process, this sulphur of the coal is fully converted into H 2S and captured with the
coke oven gas, which is used usually after cleaning of the coke oven gas i.a.for instance as fuel for
coke oven underfiring. Hence, the emissions of SO2 can be minimized by the use of coking coal with
lower sulphur content, as well as by adequate desulphurisation of the coke oven gas. For underfiring
coke oven gas and blast furnace gas can be used.
The use of desulphurised coke oven gas is considered to be BAT. And the desulphurization of coke
oven gas by absorption systems or the oxidative desulphurization is considered to be BAT.
The prevention of leakage between oven chamber and heating chamber by means of regular coke
oven operation is considered to be BAT [2]. Table 1 shows selected BAT H2S control measures with
associated H2S levels of the coke oven gas (to be later used as a fuel i.a. for coke oven underfiring).
5 July24 september 2012 Page 99

Table 1: selected BAT H2S control measures with associated H2S levels of coke oven gas [2]
Combination of control H2S level

3
measures mg/Nm
Coke oven gas Desulphurisation by absorption
500 -1000
systems
Oxidative desulphurization < 500
The BAT associated emission levels may be expected to be achieved over a substantial period of time at
standard conditions and represents a typical load situation.
According to the German IPPC implementation report from 2006 the SOx-emissions from coke oven plants in
Germany - all applying COG desulphurisation - were in the magnitude of 110-250 mg/m3 when using solely COG
(90% percentile values based on half-hourly average values from continuous measurements). When using mixed
gas (a mix mainly consisting of COG and blast furnace gas), the reported emissions were in the range of 80-160
3
mg/m .
7.6.3.2 NOx
Coke oven gas

Nitrogen emissions arising from the coke oven firing result mainly from the thermal and the chemical
fuel NOx mechanisms (refer to chapter 3.4, for the description of the different mechanisms). Chemical
Fuel NOx is due to the residual content of nitrogen compounds in the COG after cleaning e.g.
ammonia. Nevertheless, the type of fuel used is also of importance [1].
The most effective way to reduce the formation of NO x is achieved by reducing the flame temperature
in the heating chamber [1]. Therefore, the NOx emissions from the coke oven firing are preferably
minimised by process-integrated measures, but end-of-pipe techniques may also be applied.
However, due to the high cost, flue gas denitrification (e.g. SCR) is currently not applied except in a
limited number of new plants under circumstances where environmental quality standards are not
likely to be met [2].
The use of combustion modification techniques such as, low-NOx techniques, staged combustion are
considered to be BAT in new batteries. Achievable NOX emissions are 500-770 mg/Nm³.
Table 2: Emission sources and selected BAT NOx control measures with associated emission
levels in coke ovens [2]
Combination of control NOx emission level associated
Emission source 1 3
measures with BAT mg/Nm
2
Combustion of coke oven gas Combustion modification (at new 500-770 (5% O2)
plants)
1
standard conditions and represents a typical load situation. For peak load, start up and shut down periods, as well
as for operational problems of the flue gas cleaning systems, short-term peak values, which could be higher, have
to be regarded.
2
German IPPC implementation report from 2006 the NOx-emissions from coke oven: 322-414 mg as annual
average values from different plants (using both solely COG or mixed gas).
7.6.3.3 Dust (including PM10, PM2,5 and black carbon)
Information on emissions from blast furnaces that use coke oven gas can be found in the section “Iron
and steel production”.

Emissions of dust in coke ovens arise mainly from diffuse dust emission sources at the coking plant,
starting from coal handling and processing, diffuse emissions from charging holes, coke oven doors
and coke pushing, until coke quenching.
Coke ovens are a significant source of BC in developing countries according to references [4] and [5].
In western countries emissions are controlled and limited. Monitoring data are very scarce. Dust
emissions may contain a share of black carbon. Measures reducing dust emissions may consequently
reduce black carbon emissions when those measures are efficient on fine particles. Emissions of dust
(including PM10, PM2.5 and black carbon) should be prevented by minimising charging emissions (cf.
table 3), by sealing the openings efficiently and good maintenance, by minimising leakage between
coke oven chamber and heating chamber and especially by using de-dusting of coke pushing. Dust in
the waste gas from coke oven underfiring can be removed by means of fabric filters or ESP [2], [3].
levels in coke ovens [2]
Emission Dust emission level

1
source Combination of control measures associated with BAT
3
mg/Nm or (kg/tonne)
"Smokeless" charging or sequential charging
Charging With double ascension pipes or jumper pipes are the preferred; (< 5 g/t coke)
efficient evacuation and subsequent combustion and fabric
filtration
Extraction with an (integrated) hood on coke transfer machine

and land-based (< 5 g/t coke (stack
Pushing
Extraction gas treatment with fabric filter and usage of one point emissions))
quenching car
Wet quenching (< 50 g/t coke)
3
Quenching < 5 mg/m
Coke dry quenching (CDQ)
(< 6-12 g/t coke)
1
to be regarded.
Due to high costs and environmental impacts from coke use, 'direct' and 'smelting reduction'
processes may replace the blast furnace route and hence make coke production unnecessary [2].
So-called super coke ovens aim at, amongst others, reduced NOX and dust emissions.


related to the abatement of the Transboundary Transport of nitrogen oxides from stationary
sources, DFIU, 1999.
[2] European commission: Best Available Techniques Reference Document on the production of
Iron and Steel, December 2001.
[3] European commission: Best Available Techniques Reference Document on the production of
Iron and Steel, Draft February 2008.
[4] UNEP/WMO – Integrated Assessment of Black Carbon and Tropospheric Ozone – 2011.
[5] UNECE - Ad Hoc Expert Group on Black Carbon - Black carbon - Report by the Co-Chairs of
the Ad Hoc Expert Group on Black Carbon. Executive Body for the Convention on Long-range

7.7 Iron and steel production

7.7.1 Coverage
The sector covers iron and steel making in integrated steelworks (sinter plants, pelletization plants,
coke oven plants, blast furnaces and basic oxygen furnaces including continuous and ingot casting)
and electric arc furnace steelmaking [1]. Other downstream activities like ferrous metal processing in
foundries, rolling or galvanizing are dealt with within the sector “ferrous metals processing”. Emissions
originating from coke oven furnaces in iron and steel production are dealt with in the section coke
ovens.

The iron and steel industry is a highly material and energy intensive industry, in which more than half
of the mass input becomes output in the form of off-gases and solid wastes/by-products. Air emissions
from sinter plants dominate the overall emissions for most of the pollutants. Besides sinter plants,
most relevant emissions occur in pelletization plants, coke oven plants (described in the separate
section for this sector), blast furnaces, basic oxygen steelmaking and casting, and electric steelmaking
and casting [1], [2].
Sinter plants
Sinter is the product of an agglomeration process of iron-containing materials and is the source of a
major part of environmental issues in integrated steel works. This product is obtained by heating a
layer of crushed and mixed raw material (iron ore, coke, limestone …) and by exhausting flue gases
through this layer so that the surface melts and agglomerate is formed. Sinter plants are playing a very
important role for the internal material management of integrated steel works because, under
conditions, most of iron-bearing waste materials can be recycled into the sinter feed in order to utilise
their iron content and consequently save raw material. The off-gas emissions from sinter strands
contain pollutants such as dust, heavy metals, SO 2, HCl, HF, PAH and organochlorine components
[1], [3].
Sinter plants are not recognized as a significant source of BC according to references [10], [11] and
[13]. Monitoring data are very scarce.
Pelletization plants
Pelletization is an alternative process to agglomerate iron-containing materials, with pellets being
produced mainly at the site of the mine or its shipping port. Again, emissions to air dominate the
environmental issues [1], [9].
Pelletization plants are not recognized as a significant source of BC according to references [10], [11]
and [13]. Monitoring data are very scarce.
Coke oven plants are not subject of this part, but are dealt with in chapter 7.6.
Blast furnaces
The blast furnace remains by far the most important process to produce pig iron from iron containing
materials. These are reduced using carbon and hot gas to pig iron, which later acts as a raw material
for steelmaking. Due to the high input of reducing agents (coke, pulverized coal) it consumes most of
the overall energy input in an integrated steelworks [1]. It produces a high volume of process gas,
which needs to be cleaned before being used for internal combustion or for internal/external
generation of energy.
Although the blast furnace route is the main process for iron production, several other production
routes for pig iron are currently being developed. Two main types of alternative iron making are direct
reduction (production of solid primary iron from iron ores and a reducing agent, e.g. natural gas) and
smelting reduction (combining direct reduction in one reactor with smelting in a separate reactor,
without the use of coke). COREX is a commercially successful version of a 'smelting reduction'

process [4]. These techniques use coke, coal or natural gas as the reduction agent. In some of the
new techniques lump ore and pellets by pulverized iron ore as the main feedstock. The solid product is
called Direct Reduced Iron (DRI) and is mainly applied as feedstock in EAFs [4], [9].
Blast furnaces are not recognized as a significant source of BC according to references [10], [11] and
[13]. Monitoring data are very scarce.
Basic oxygen steelmaking and casting

The objective of oxygen steelmaking is to reduce the carbon content and to remove the undesirable
impurities still contained in the hot metal from the blast furnace. It includes the pre -treatment of hot
metal, the oxidation process in the basic oxygen furnace, secondary metallurgical treatment and
casting (continuous and/or ingot). In addition to hot metal, up to 25% scrap can be used as input
material. Collected basic oxygen furnace (BOF) gas is cleaned and stored for subsequent use as a
fuel, if economical feasible or with regard to appropriate energy management [1], [4].
Basic Oxygen oxygen furnaces are not recognized as a significant source of BC according to
references [10], [11] and [13]. Monitoring data are very scarce.
Electric steelmaking and casting

The direct smelting of iron-containing materials, mainly scrap, is usually performed in electric arc
furnaces. This needs considerable amounts of electric energy and causes substantial emissions to air.
The energy consumption (and the corresponding amount of CO 2 emissions) from steel production in
electric arc furnaces is about one third of the energy consumption of the blast furnace / basic oxygen
furnace route. The use of this 'lower CO 2 production route' is however limited by the availability of
scrap and certain qualities of steel can only be achieved via the primary production route [1].
Electric arc furnaces are not recognized as a significant source of BC according to references [10],
[11] and [13]. Monitoring data are very scarce.
7.7.3.1 SO2
For sinter plant emissions, SO2 can be minimised by lowering the sulphur input (use of coke breeze
and iron ore with low sulphur content), emission concentrations of <500 mg SO2/Nm³ can be achieved
in this way. SO2 emissions from sinter plants may also be reduced by dry or semi-dry adsorption
systems in combination with high-efficiency dust filters (as part of a multi-pollutant control technique).
With a wet waste gas desulphurization, reduction of SO 2 emissions >98% and concentrations < 100
mg SO2/Nm³ can be achieved. Due to the high cost wet waste gas desulphurisation should only be
required in circumstances where environmental quality standards are not likely to be met [1]
operational reliability (availability ratio of the equipment) is also questioned.
For pelletization plants, dust, SO2 and other pollutants can be removed from induration strand waste
gas either by scrubbing or semi-dry desulphurization and subsequent de-dusting (e.g. gas suspension
absorber (GSA)) or by any other device with the same removal efficiency [1].
Addition of adsorbents such as hydrated lime, calcium oxide or fly ashes with high calcium oxide
content may be used to further reduce SO 2 emissions, when injected into the exhaust gas outlet before
filtration [9].

Table 1: SO2 emission levels associated with BAT for iron and steel production
Emission Source BAT associated Comments
1
emission levels
3
mg/Nm or (kg/tonne)
< 500
Sinter plants [1] 500 according to BREF
(1)
SO2 as SO2; using system with removal
Pelletization plants [1] < 20
efficiency >80%
Related to an oxygen content of 3%
Blast furnaces: cowpers (hot In the German IPPC implementation report

stoves) < 200 from 2006 a range of 60-210 mg/m is
3
reported as 5% and 95% percentiles based

on half-hourly average values from
continuous measurements.
1
to be regarded.
7.7.3.2 NOx
For sinter plants, NOX emissions should be minimized by, for example waste gas recirculation, waste
gas denitrification using regenerative activated carbon process or selective catalytic reduction.
Regenerative activated carbon and selective catalytic reduction are options for reducing NO X
emissions, but have not yet been applied in the UN-ECE region on full scale due to their high costs
(currently SCR is tested in pilot plant scale at one European steel plant) [1].
For pelletization plants it is considered BAT to optimise plant design for recovery of sensible heat
and low-NOx emissions from all firing sections (induration strand, where applicable and drying at the
grinding mills) [1]. For one pelletization plant, NO X emissions of 175 g/tonne pellet are achieved using
process-integrated measures only, namely by a combination of low energy use, low nitrogen content
in the fuel (coal and oil) and limiting the oxygen excess [5], [6].
The application of modern burners may reduce NOx emissions of to blast furnace cowpers.

Table 2: NOX emission levels associated with BAT for iron and steel production
1
emission levels
3
mg/Nm or (kg/tonne)
Related to an oxygen content of 3%
In the German IPPC implementation report

Blast furnace (hot stoves) [1] 20-120 3
from 2006 a range of 20-120 mg/m is
reported as 5% and 95% percentiles based
on half-hourly average values from
continuous measurements.
300-400 Normal operation conditions
1
Sinter plants [6]
2 3
100-120 SCR
1
to be regarded.
2
The emission level is based on data from Japan and Taiwan
3
Due to the high cost, waste gas denitrification is not applied except in circumstances where environmental
quality standards are not likely to be met.
Fabric filters should be used whenever possible, reducing the dust content to less than 20 mg/m³
(hourly average). If conditions make this impossible (due to their tendency to blind and their sensitivity
to fire), advanced ESPs and/or high-efficiency scrubbers may be used, reducing the dust content to 50
mg/m³. Many applications of fabric filters can achieve much lower values [4], [7].
Sinter plants may generate the most significant quantity of dust emissions in integrated steel mills,
they arise primarily from material handling and from the agglomeration reaction on the strand.
Dust (together with PCDD/F) is furthermore the most important pollutant in sinter plants and waste gas
de-dusting is considered BAT, for example by application of advanced electrostatic precipitation
(moving electrode ESP, ESP pulse system, high voltage operation of ESP) or electrostatic
precipitation plus fabric filter or pre-dedusting (e.g., ESP or cyclone) plus high pressure wet scrubbing
system. The presence of fine dust, which mainly contains alkali and lead chlorides may limit the
efficiency of ESPs.
BAT also includes to use enclosure and/or hooding, where appropriate, with emission controls, of the
sinter strand operations that are potential sources of fugitive emissions, as well as to apply operating
practices that minimize fugitive emissions that are not amenable to enclosure or hooding. For reducing
dust emissions from material handling operations indoor or covered stockpiles, when possible, as well
as a simple and linear layout for material handling should be used. Enclosed conveyer transfer points
and enclosed silos to store bulk powder can further reduce emissions from bulk powder materials
(fugitive emissions of coal dust are a major concern here) [1], [4], [9].
BC emission monitoring data are scarce. When present in dust, BC emissions can be removed, at
least partially, by the use of the same BAT measures described just above for dust when those
measures are efficient for the concerned size of particles.
For information for pelletization plants see above (chapter 7.7.3.1).

For blast furnace gas treatment, an efficient de-dusting is considered BAT using dry separation
techniques (e.g. deflector) for removing and reusing coarse particulate matter. Subsequently fine
particulate matter is removed by means of a scrubber or a wet electrostatic precipitator or any other
technique achieving the same removal efficiency. For cast house de-dusting, emissions should be
minimized by covering the runners and evacuation of the emission sources (tap-holes, runners,
skimmers, torpedo ladle charging points) and purification by means of fabric filtration or electrostatic
precipitation [1].
BC emission monitoring data are scarce. When present in dust, BC emissions can be removed, at
least partially, by the use of the same BAT measures described just above for dust when those
measures are efficient for the concerned size.
For basic oxygen steelmaking and casting including hot metal pre-treatment, secondary
metallurgical treatment and continuous casting (including hot metal transfer processes,
desulphurization and deslagging), BAT is considered to use particulate matter abatement by means of
efficient evacuation and subsequent purification by means of fabric filtration or electrostatic
precipitation. For basic oxygen steelmaking and casting, the use of a whirl hood for secondary
dedusting aims at reducing dust emissions.
Basic oxygen furnace gas recovery and primary de-dusting is considered BAT applying suppressed
combustion and dry electrostatic precipitation (in new and existing installations) or scrubbing (in
existing installations). Secondary de-dusting is considered BAT applying efficient evacuation during
charging and tapping with subsequent purification by means of fabric filtration or ESP or any other
technique with the same removal efficiency. Efficient evacuation should also be applied during hot
metal handling, deslagging of hot metal and secondary metallurgy with subsequent purification by
means of fabric filtration or any other technique with the same removal efficiency [1].
No BC emissions occur according to reference [12]. When present in dust, BC emissions can be
removed, at least partially, by the use of the same BAT measures described just above for dust when
those measures are efficient for the concerned size.
For electric steelmaking and casting, BAT is considered to achieve dust collection efficiencies with
a combination of direct off gas extraction (4th or 2nd hole) and hood systems or dog -house and hood
systems or total building evacuation of 98% (primary and secondary emissions). Waste gas de -dusting
is considered BAT using well designed fabric filters achieving 5 mg dust/Nm³ for new plants and 15
mg dust/Nm³ for existing ones, both determined as daily mean values [1].
No BC emissions occur according to reference [12]. BC emission monitoring data are however scarce.
When present in dust, BC emissions can be removed, at least partially, by the use of the same BAT
measures described just above for dust when those measures are efficient for the concerned size.

Table 3: Dust emission levels associated with BAT for iron and steel production
[Comment: [9] recommends maximum dust emission levels of 50 mg/Nm³ for all operations in integrated steel
mills, 20 mg/Nm³ when toxic metals are present]

1
emission levels
3
mg/Nm or (kg/tonne)
< 50 [1] Existing sinter plants equipped with
advanced ESPs
Sinter Plants
10-20 [1] Application of fabric filters
(0.04-0.12) [4]
10 [1] Using a system with removal efficiency
Pelletization plants
(0.04) [4] >95%
< 10 [1] Related to an oxygen content of 3%
Blast furnaces: Hot stoves (0.035-0.05) [4] kg/tonne pig iron
Blast furnaces: fugitive (0.005-0.015) [1] US EPA 1998 [1][8] reports the following
emissions (fully captured) shares of PM1 in dust: Casthouse (older
type): 15%; Furnace with local evacuation:
9%; Hot metal desulphurization: 2%
5-15 [1] Fabric filters
20-30 [1] ESP
Basic oxygen steelmaking
and casting (0.035-0.07) [4] US EPA 1998 [8] [8] reports the following
shares of PM1 in dust: Charging (at source)
12%;Tapping (at source) 11%
2 3
< 5 [1][1]; (0.06) [4] For new plants
2 3
< 15 [1][1]; (0.12) [4] For existing plants
Electric steelmaking and
casting US EPA 1998 [8] [8] reports the following
shares of PM1 in dust for EAF: Melting and
refining (carbon steel, uncontrolled): 23%
1
to be regarded.
2
For this value: daily mean
3
Recommended performance indicator
Note:
The International Finance Corporation [9] recommends maximum dust emission levels of 50 mg/Nm³
for all operations in integrated steel mills, 20 mg/Nm³ when toxic metals are present.
In the Iron & Steel Industry BREF document, there is to emphasize that only the air emissions at EAF and the
water data at Blast Furnace are expressed as daily averages when all other BAT AELs have been expressed
under normal operation conditions (e.g. excluding start up and shut down periods) and design, and averaged on a
substantial period of time (there is not yet any consensus reached about this definition)
7.7.3.4 VOC
Volatile organic compounds and polycyclic aromatic hydrocarbons (PAH) may be emitted from various
stages in iron and steel production. These include off gases in the pelletization and sintering

processes due to carbon compounds contained in the solid fuels of sinter or pelletization feed, for
example from the addition of mill scale [9].
As this sector is not considered a major emitter of VOC, no further information is given on emission
levels associated with BAT.
7.7.3.5 Cross Media Effects
For all mentioned emission reduction and abatement techniques, the cross-media transfer of
pollutants and the full range of environmental effects and improvements should be considered. For
example additional energy consumption and increased quantities of waste or wastewater residuals
may result from individual efforts for pollutant prevention, reduction, or removal.
Especially de-dusting using ESP or FF leads to an additional solid waste flow, which can be recycled
into the process for some cases. If the bags in FF are precoated by injecting slaked lime, significant
abatement of some acidic components (HCl, HF) can also be achieved. In combination with an
injection of lignite coke or activated carbon, FF also help to reduce PCDD/PCDF emissions
3
significantly (to below 0.1 to 0.5 ng/m ). The minimisation of dust emissions correlates with the
minimisation of heavy metal emissions except for heavy metals in the gas phase like mercury [1], [2].

Direct reduction and direct smelting are under development (cf.refer to section description of
production technologies) and may reduce the need for sinter plants and blast furnaces in the future.
The use of new reagents in the hot metal desulfurization process might lead to a decrease in dust
emissions and a different (more useful) composition of the generated dust. The technique is unde r
development. Several foaming techniques at pig iron pre-treatment and steel refining are already
available, absorbing the dust arising from the hot metal processing [4].
For electric arc furnaces, intermetallic bag filters combine filtering and catalytic operations and allow to
reduce dust and associated pollutant emissions [2]. Additionally, a number of new furnace types have
been introduced, that might be realized at industrial scale, and that show advantages with regard to
heavy metals and dust emissions, e.g.:
Comelt EAF (integrated shaft scrap preheating and a complete off gas collection in each operating
phase)
Contiarc furnace (waste gas and dust volumes are considerably reduced, and the gas-tight furnace
enclosure captures all primary and nearly all secondary emissions)

7.7.5 Cost data for emission reductions
8 Table 4: examples of investments and operating costs of control options for the abatement of
NOx emissions [6]
Mis en forme : Justifié, Espace Après
7.7.5 : 0 pt, Sans numérotation ni puces
a/ b/
Characteristics of Control options Investments Operating costs Abated mass flow
reference installation [EURO] [EURO/year] [Mg NOx/year]
Source: previous guidance document

Iron and steel production: sinter plant
e/1
Travelling grate sinter Flue gas 5,000,000 - 200,000 2,000
machine; Fuel: coke recirculation
breeze; Production
output: 12,000 Mg
sinter/day; SCR 50,000,000 5,300,000 3,200
Operating time: 8,400
h/year
1
Due to reduced coke breeze consumption
[Comment: UNECE 2006 states “Total costs of implementing FFs for one representative sinter plant are 3000 to
16000 Euro p.a.”]
Mis en forme : Espace Avant : 6 pt,
7.7.6 References used in chapter 7.7 Après : 6 pt, Hiérarchisation + Niveau :
3 + Style de numérotation : 1, 2, 3, …
[1] European Commission. 2001: “Integrated Pollution Prevention and Control (IPPC) Best + Commencer à : 6 + Alignement :
Available Techniques Reference Document on the Production of Iron and Steel.” Gauche + Alignement : 2.49 cm +
http://eippcb.jrc.es/pages/FActivities.htm Retrait : 3.76 cm
[2] European Commission. 2008 Draft: “Integrated Pollution Prevention and Control (IPPC) Best
Available Techniques Reference Document on the Production of Iron and Steel.”
http://eippcb.jrc.es/pages/FActivities.htm
[3] IIASA 2004: International Institute for Applied Systems Analysis. Interim Report IR -04-079
”Primary Emissions of Submicron and Carbonaceous Particles in Europe and the Potential for
their Control“.
[4] Kraus, K., S. Wenzel, G. Howland, U. Kutschera, S. Hlawiczka, A. P. Weem and C. French
(2006): Assessment of technological developments: Best available techniques (BAT) and limit
values. Submitted to the Task Force on Heavy Metals, UNECE Convention on Long-range
Transboundary Air Pollution.
[5] The nordic council of ministers 2005: “BAT examples from the Nordic iron and steel industry“
http://www.norden.org/pub/miljo/miljo/uk/TN2006509.pdf.
[6] UNECE 1999. “Draft guidance documents on control techniques and economic instruments to
the protocol to abate acidification, eutrophication and ground level ozone”.
[7] IFC 2007. International Finance Corporation (World Bank Group): “Environmental, Health, and
Safety Guidelines for Base Metal Smelting and Refining”.
th
[8] US EPA 1998: “Compilation of air pollutant emission factors”, 5 edition: EPA AP-42. United
States Environmental Protection Agency.
Safety Guidelines for Integrated Steel Mills”.
[10] UNEP/WMO – Integrated Assessment of Black Carbon and Tropospheric Ozone – 2011.

[12] Kupiainen, K. & Klimont, Z., 2004. Primary Emissions of Submicron and Carbonaceous
Particles in Europe and the Potential for their Control. International Institute for Applied Systems
Analysis (IASA), Interim report IR-04-79, Schlossplatz 1 A-2361 Laxenburg Austria.
[13] EPA – Report to congress on black carbon – March 2012.

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including PM10, PM2,5
7.8 Ferrous metals processing including iron foundries

7.8.1 Coverage
This section on ferrous metals processing comprises iron foundries (for continuous and ingot casting
see chapter “Iron and steel production”) with a capacity exceeding 20 tonnes/day, as well as
installations for “hot and cold forming”, including hot rolling, cold rolling, wire drawing, installations for
“continuous coating”, including hot dip coating and coating of wire, and installations for “batch
galvanizing” [1], [2].

7.8.2.1 Foundries
Foundries melt metals and alloys (only ferrous metals regarded in the following) and reshape them
into products at or near their finished shape through the pouring and solidificatio n of the liquid metal
into a mould. Fluxes and fuels are similar as in pig iron processing. The industry consists of a wide
range of installations, most of them comprising the process steps: melting and metal treatment,
preparation of moulds and core, casting the molten metal in the mould, cooling for solidification and
removing, finishing the raw casting. The main environmental issues of this industry are emissions to
air (dust, acidifying compounds, products of incomplete combustion and volatile organic compounds)
[2], [3].
7.8.2.2 Hot and cold forming

In hot rolling, the size, shape and metallurgical properties of steel are changed by repeatedly
compressing the hot metal (1050-1300 °C) between rollers. The steel input varies in form and shape –
cast ingots, slabs, blooms, billets, beam blanks – depending on the product, generally classified in the
basic types flat and long products. Hot rolling mills usually comprise the following process steps:
conditioning of the input (scarfing, grinding); heating to the rolling temperature; descaling; rolling and
finishing. The main environmental issues of hot rolling are emissions to air, especially NO X and SO2,
energy consumption and dust emissions.
In cold rolling, the properties of hot rolled strip products (thickness, mechanical and technological
characteristics) are changed by compression between rollers without previous heating. The process
steps for low alloy steel (carbon steel) are pickling, rolling for reduction in thickness, annealing or heat
treatment to regenerate the crystalline structure, temper rolling or skin pass rolling of annealed strip to
give desired mechanical properties and finishing. The process steps for high alloy steel (stainless
steel) involves additional steps, the main stages are: hot band annealing and pickling, cold rolling, final
annealing and pickling (or bright annealing), skin pass rolling and finishing. The main environmental
issues of cold rolling are acidic waste and waste water, degreaser fume acidic and oil mist emissions
to air, dust and NOX (mixed acid pickling and furnace firing).
Wire drawing is a process in which wire rods/wires are reduced in size by drawing them through
cone-shaped openings of a smaller cross section, called dies. A typical plant comprises the following
process lines: pre-treatment (descaling, pickling), dry or wet drawing, heat treatment and finishing.
The main environmental aspects of wire drawing are air emissions from pickling, acidic wastes and
waste water, fugitive soap dusts, spent lubricants and combustion gases [1].
7.8.2.3 Continuous hot dip coating

In the hot dip coating process, steel sheet or wire is continuously passed through molten metal. An
alloying reaction between the two metals takes place, leading to a good bond between coating and
substrate. Continuous coating lines for sheet comprise the steps surface cleaning (chemical or thermal
treatment), heat treatment, immersion in a bath of molten metal, and finishing treatment. Continuous
wire galvanizing plants involve the steps pickling, fluxing, galvanizing, finishing. Main environmental
issues are acidic air emissions, waste and wastewater and energy consumption [1].

7.8.2.4 Batch galvanizing

Hot dip galvanization is a corrosion protection process in which iron and steel fabrications are coated
with zinc. Prevalent in this sector is job galvanizing, in which a great variety of products are treated for
different customers; batch galvanizing usually comprises the steps degreasing, pickling, fluxing,
galvanizing, finishing. The main environmental issues are emissions to air (HCl, dust) spent process
solutions and oily wastes and zinc containing residues [1].

7.8.3.1 SO2
For re-heating and heat treatment furnaces in hot rolling installations, a careful choice of fuel and
implementation of furnace automation/control to optimise the firing conditions is considered BAT.
Process waste gases are commonly used at reheating furnaces in place of fossil fuels. Fuels with low
S content are commonly used [1].
Table 1: SO2 emission levels associated with BAT for ferrous metals production
1
emission levels
3
mg/Nm or (kg/tonne)
20-100 Hot blast cupola
Foundries: ferrous metal
100-400 Cold blast cupola
melting [2]
70-130 Rotary arc furnace
Moulding and casting using
lost moulds (regeneration 120
units) [2]
100 For natural gas
Hot rolling: re-heating and
400 For all other gases and gas mixtures
heat treatment furnaces [1] 2
1700 for fuel oil <1%S
Recovery of the free acid by crystallisation;
Cold rolling: H 2SO4-pickling 8-20 air scrubbing devices for recovery plant.
Cold rolling: HCl-pickling [1] 50-100 Regeneration of the acid by spray roasting
or fluidised bed (or equivalent system)
1
2
EU-BREF split view if fuel oil <1%S is BAT or additional SO 2 reduction measures are necessary
7.8.3.2 NOX
For re-heating and heat treatment furnaces in hot rolling installations, the use of second generation
low-NOX burners is considered BAT. [comment: BREF2001 split view on whether SCR and SNCR are
BAT for re-heating and heat treatment furnaces in hot rolling installations]
For mixed acid pickling in cold rolling installations, it is considered BAT to use either free acid
reclamation (by side-stream or ion exchange or dialysis) or acid regeneration by spray roasting or acid
regeneration by evaporation process. In general for mixed acid pickling in cold rolling installations,
enclosed equipment/hoods and scrubbing should be used, and additionally for high alloy steels either
scrubbing with H2O2, urea, etc. or NOX suppression by adding H 2O2 or urea to the pickling bath or by
use of SCR. An alternative is to use nitric acid-free pickling plus enclosed equipment or equipment
fitted with hoods and scrubbing. For annealing furnaces in cold rolling installations, it is BAT to use low
NOX burners for continuous furnaces, combustion air preheating by regenerative or recuperative
burners or pre-heating of stock by waste gas.
For continuous hot dip coating, it is considered BAT to use low-NOX burners and regenerative or
recuperative burner for heat treatment furnaces and galvannealing. For heat treatment furnaces, it is

additionally BAT to use pre-heating of the strip and steam production to recover heat from waste gas
where there is a need for steam [1].
Table 2: NOX emission levels associated with BAT for ferrous metals production
1
emission levels
3
mg/Nm or (kg/tonne)
10-200 Hot blast cupola
20-70 Cold blast cupola
Foundries: ferrous metal
160-400 Cokeless cupola
melting [2]
10-50 Electric arc furnace
50-250 Rotary arc furnace
Moulding and casting using
lost moulds (regeneration 150
units) [2]
390 Fuel: blast furnace gas; low NOX burner
1100 Fuel: coke oven gas, heavy fuel oil; low NO X
Hot rolling: re-heating and burner
heat treatment furnaces [1]
250-400 Fuel: natural gas, gas oil; low NO X burner
3% O2 for gas, 6% O2 for liquid fuel
3 2
Hot rolling: re-heating and 320 SCR
3 2 3
heat treatment furnaces 205 SNCR , ammonia slip 5 mg/Nm
2 2
using SCR and SNCR [1] 3% O2 for gas, 6% O2 for liquid fuel
Cold rolling: HCl pickling [1] 300-370
200-650
Cold rolling: mixed acid
200 Acid regeneration by spray roasting
pickling [1]
100 Acid regeneration by evaporation process
Cold rolling: annealing Without air pre-heating, 3% O2, reduction
250-400
furnaces [1] rates of 60% for NOX
Hot dip coating: heat
treatment furnaces and 250-400 Without air pre-heating, 3% O2
galvannealing [1]
1
2
EU-BREF split view if SCR and SNCR are BAT (only one of each installation exists in Europe)
3
These are emission levels reported for the one existing SCR plant (walking beam furnace) and the one existing
SNCR plant (walking beam furnace).

For foundries, a key issue in emission reduction is not only to treat the exhaust and off -gas flow, but
also to capture it. BAT is to minimize fugitive emissions arising from various non-contained sources in
the process chain like from furnaces during opening or tapping by optimizing capture and cleaning,
clean furnace off-gas by subsequent collection, cooling and dust removal. For cupola furnace melting
of cast iron, BAT for dust reduction is to improve thermal efficiency and use a fabric filters or wet
scrubbers.
For the operation of induction furnaces, BAT is, amongst others, use a hood, lip extraction or cover
extraction on each induction furnace to capture the furnace off-gas and to use dry flue-gas cleaning
[2].
For finishing techniques like abrasive cutting, shot blasting and fettling, BAT is to collect and treat the
finishing off gas using a wet or dry system. For heat treatment, BAT is to use clean fuels (i.e. natural
gas or low-level sulphur content fuel), automated furnace operation and burner/heater control and also
to capture and evacuate the exhaust gas from the heat treatment furnaces.

For hot rolling, it is considered BAT to use enclosures for machine scarfing and dust abatement with
fabric filters or electrostatic precipitators, where fabric filters cannot be operated because of wet fume.
For machine grinding operations in hot rolling installations, BAT is to use enclosures for machine
grinding and dedicated booths, equipped with collection hoods for manual grinding and dust
abatement by fabric filters. In the finishing train, exhaust systems with treatment of extracted air by
fabric filters and recycling of collected dust is considered BAT. For levelling and welding, suction
hoods and subsequent abatement by fabric filters are considered BAT.
For cold rolling, it is BAT to use extraction hoods with dust abatement by fabric filters in levelling and
welding operations.
1
For coating of wire, it is considered BAT to use good housekeeping measures for hot dipping [1].
Iron and steel foundries are not recognised as a significant source of BC according to references [7],
[8]. Monitoring data are very scarce. No emission factor is proposed by reference [9]. When present in
dust, BC emissions can be removed, at least partially, by the use of the same BAT measures
described just above for dust when those measures are efficient for the concerned size.
Table 3: dust emission levels associated with BAT for ferrous metals production
1
emission levels
3
mg/Nm or (kg/tonne)
daily average, standard conditions
Iron Foundries [2] 5-20
Iron foundries: induction

(0.2)
furnaces [2]
2
5 / 20 Fabric filters
Hot rolling: machine scarfing 10 / 20-50
2
[1] ESP, where FF cannot be operated because

of wet fume
2
Hot rolling: grinding [1] 5 / 20
Hot rolling: finishing train and 2
5/ 20
levelling and welding[1]
2
Cold rolling: decoiling [1] 5 / 20
Cold rolling: HCl pickling [1] 20-50
Cold rolling: levelling and 2
5 / 20
welding [1]
Coating of wire: hot dipping
10
[1]
Galvanizing baths [4] 15
1
2
EU-BREF 2001 split view
7.8.3.4 VOC
In foundries, various additives are used to bind the sand in the making of moulds and cores; These
include organic and inorganic compounds (solvents, BTEX, phenol, formaldehyde, etc.): the
generation of decomposition products further continues during the casting cooling and de -moulding
operations. As the process involves various emission sources (hot castings, sand, hot metal), a key
issue is not only to treat the off-gas, but also to capture it [5].
Hydrocarbons and misted oil emissions may arise from the cold rolling mill operations, advanced
emission collection and demisting systems like precoated fabric filters can be used to reduce them [6].
1
Cf. EIPPCB BREF 2001, Chapter B.4

Table 4: VOC emission levels associated with BAT for ferrous metal processing
1
emission levels
3
mg/Nm or (kg/tonne)
Foundries: Ferrous metal 10-20 Cold blast cupola
melting
1


For hot and cold rolling, the flameless burner or diffuse flame maximises recirculation of the flue gas
and has punctually achieved NOX emission levels of 100 mg/m³, however no industrial application
exists until now. Reductions of NOx emissions are also aimed at by the ultra low-NOx burner
(complete mixing of fuel and combustion air in the furnace, thus no anchoring of the flame in the
furnace) and water injection (reduction of temperature and thus thermal NOx formation) [1].


Table 5: cost information for different NOX reduction techniques for a 50 MW furnace [1]
Technique Typical range Capital Operating Total cost of technique
of cost cost (GBP ‘000/year for 50 MW furnace)
NOX reduction (GBP (GBP/GJ)
‘000) 2000 4000 8000
hours/year hours/year hours/year
Low-NOX
Up to 97% 328 0.0 53.7 53.7 53.7
burners
0.0257
Limiting air for 50 %
NA 92.5 185 370
preheat NOX
reduction
Up to 93% 75.6
Flue gas 0.098 47.6 82.9 153
(44.74 (631)*
recirculation (0.072)* (129)* (154)* (206)*
15 % FGR)
up to 95%
1100 -
SCR (Typically 70 - 0.0722 205 - 438 231 - 464 283 - 516
2530
90)
up to 85%
SNCR
(Typically 50 - 350 - 650 0.0361 69.9 - 119 82.9 - 132 109 - 158
(with NH3)
60)
Cost given in 1996 British Pounds
NA Not available and, for the purposes of calculation, assumed to be small compared with operating cost.
* Figures in brackets refer to case where burners and regenerators would need to be uprated.
NB1 Flue gas recirculation operating cost figures all based on 15 % FGR.
Estimated fuel consumption penalty = 3.2 %
Increased fan running costs (based on regenerative burners) = 1.6 % of fuel costs (0.32 % if burners and
regeneratoars were uprated).
NB2 Water injection cost figures all based on 15 kg (water)/GJ (fuel):
Estimated fuel cost penalty = 11.8 %
Cost of water not included


[1] European Commission. 2001: “Integrated Pollution Prevention and Control (IPPC) Reference
Document on Best Available Techniques in the Ferrous Metals Processing Industry.”
Document on Best Available Techniques in the Smitheries and Foundries Industry.”
[3] IIASA 2004: International Institute for Applied Systems Analysis. Interim Report IR -04-079
„Primary Emissions of Submicron and Carbonaceous Particles in Europe and the Potential for
their Control“.
[4] DEFRA 2006: Sector Guidance Note IPPC SG5 - Secretary of State's Guidance for A2 Activities
in the Galvanising Sector. http://www.defra.gov.uk
Safety Guidelines for Foundries”
Safety Guidelines for Integrated Steel Mills”
[7] UNEP/WMO – Integrated Assessment of Black Carbon and Tropospheric Ozone – 2011
the Ad Hoc Expert Group on Black Carbon. Executive Body for the Convention on Long -range
Transboundary Air Pollution. Twenty-eighth session Geneva, 13–17 December 2010
Analysis (IASA), Interim report IR-04-79, Schlossplatz 1 A-2361 Laxenburg Austria

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including
PM10, PM2,5 and black carbon) from stationary sources
7.9 Non ferrous metal processing industry1

7.9.1 Aluminium
7.9.1.1 Coverage
Aluminium industry is the largest non ferrous metal industry. This chapter covers primary and
secondary aluminium production.
7.9.1.2 Emission sources

Aluminium production is divided into 2 types of production, the primary production and the secondary
production.
In primary production, alumina is the raw material used to produce aluminium. Alumina is produced
from the bauxite, extracted from mines. Caustic soda is used to extract alumina from bauxite, using a
standard process at high temperature and pressure. Aluminium is then produced by electrolytic
reduction of alumina. During this process the exhaust gases are collected and treated by a dry
alumina scrubber and dust treatment system such as ESP or bag filters. Further abatement systems
might be considered on a case-by-case basis.
The obtained aluminium is then refined to remove impurities by injection of gas in the molten metal.
The choice of the gas depends on the type of impurities. These processes are sources of dust, SO 2
and NOx emissions. [1].
In secondary production, aluminium comes from scraps. These scraps can be pre-treated (swarf
drying or thermal de-coating) before being processed to produce aluminium.
Different furnaces, mainly rotary or reverberatory furnaces can be used to melt the raw material.
Natural gas, which does not contain sulphur, is the fuel most commonly used. The obtained aluminium
is then refined in a holding furnace as in the primary aluminium production. These processes are
sources of dust, SO2 and NOx emissions. [1].
7.9.1.3 BAT, Associated Emission Levels (AEL)

If not stated otherwise, emission levels given in this section are given as daily average based on
continuous monitoring and standard conditions of 273 K, 101.3 kPa, measured oxygen content and
dry gas without dilution of the gases with air.
SO2:
In primary aluminium production, SO2 emissions are influenced by the sulphur content of the anodes
used during the electrolytic reduction. In secondary production, and in the production of carbon
anodes for the Prebake primary production, the possible source of SO 2 emissions is the sulphur
content of the fuel used. SO2 emissions do not generally cause the greatest concern during the
aluminium production process, however this has to be considered on a case-by-case basis, depending
on the local and environmental conditions.
In primary aluminium production, BAT to reduce SO2 emissions is to limit sulphur content fuel and
anodes, subject to their market availability. For secondary aluminium production, wet or semi-dry
alkaline scrubbers are considered BAT to reduce SO 2 emissions from the holding and degassing of
molten metal process, material pretreatment process, and melting and smelting processes.
The applicability of SO2 abatement systems has to be assessed on a case-by-case basis, taking into
account the technical characteristics of the plant, the geographical location and the local conditions,
with particular reference to possible cross-media effects
1
The information included in this subchapter is based on the NFM BREF [1], which is currently under revision in
June 2009 at the Institute for Prospective Technological Studies in Sevile (IPTS)..

a/
Table 1: associated SO2 emission levels with BAT to reduce emissions in aluminium industry
[1] [10]
Associated
emission level
Emission source Techniques
with BAT
3
(mg/Nm )
Holding and degassing of molten metal in primary < 50 – 200
and secondary aluminium production
Materials pre-treatment, melting and smelting in

wet or semi-dry alkaline < 50 – 100
secondary aluminium production
scrubber (if needed)
Grinding, mixing and baking stages (if sulphur is
added to the blend or the fuel contains high %S)
[1] < 50 - 200
a/ The information included in Tab. 1 is currently under discussion in the context of the NFM BREF revision, .
whose conclusion is anticipated in Q1 2010. It would be advisable not to include this table to avoid possible
confusion once the new NFM BREF is adopted or, at least, to clarify that this information, including BAT-AELs, is
under revision.
NOx:
In aluminium production NOx emissions come from the combustion processes used to melt the raw
materials. Emissions are influenced by different parameters: the type of fuel, the type of combustion,
the combustion air-ratio and the flame temperature. Oxy-fuel burner and low NOx burners are the
measures considered BAT to reduce NOx emission in aluminium production. [1].
The following table gives an overview of achievable NOx emission levels in aluminium production.
Table 2: associated NOx emission levels with BAT to reduce emissions in aluminium industry
[1][1] Mis en forme : Police :Non Gras,
Anglais (États Unis)
Associated
emission level
with BAT
3
(mg/Nm )
furnaces from primary
Low NOx burner < 100
and secondary aluminium
Oxy-fuel burner < 100 - 300
and swarf drying
Dust (including PM10, PM2.5 and BC)

In primary aluminium production, dust emissions come mainly from alumina production process,
electrolysis, smelting and casting processes. This source is not identified as a large emitter of BC
according to references [15], [16]. BC emission data are scarce. According to [17], there is no BC
emission in primary aluminium and 1.2 g BC/t aluminium produced in secondary aluminium plants.
Flue gases from production of alumina need to be collected and a fabric filter or ESP can be used to
remove calcined alumina and dust. Collected gases from other processes need to be dedusted. A
fabric filter can be used. A wet scrubber can also be used depending on local conditions . [6] Mis en forme : Police :Non Gras
In secondary aluminium production, pre-treatment, secondary smelting and holding are sources of
dust emissions. Ceramic or fabric filters can be used to remove dust from the collected gases of
secondary smelting process. For the other processes, flue gases need to be collected and can be
filtered using a fabric filter when it is needed. [1].

The collected dust from the filters has to be reused when it is possible.
The material reception, handling and storage are sources of fugitive d ust emissions. These emissions
have to be minimized by a good handling and protections from the wind of raw material.
The following table gives an overview of achievable dust emission levels in aluminium production. [3]
The preferred technique for dust abatement is the use of a fabric filter or a ceramic filter.
If present in dust, BC emissions can be removed, at least partially, by the use of the same BAT
measures described in table 3 for dust which are also efficient for fine particles.
Table 3: associated dust emission levels with BAT to reduce emissions in aluminium industry
[1][1], [4][4] Mis en forme : Police :Non Gras,
Anglais (États Unis)
Associated emission level with
Mis en forme : Police :Non Gras,
Emission source Techniques BAT
3 Anglais (États Unis)
(mg/Nm )
Electrolysis, Pre-treatment Fabric filter
Dust: 1 – 5
Primary & secondary smelting Ceramic or fabric filter

7.9.2 Copper
7.9.2.1 Coverage
Copper is largely used for its very high thermal and electrical conductivity, its relative resistance to
corrosion and its easiness to be recycled. This category covers copper production from primary and
secondary processing.

Copper production is divided into 2 productions, the primary production and the secondary production.
Primary production
The concentrates used to produce primary copper are mainly sulphides and contain other metal than
copper. Therefore several processes are used to separate the different compounds and recover them
as far as possible. Due to the composition of the concentrates (sulphides), SO 2 emission level is high
during these processes.
2 methods are used to produce primary copper: pyrometallurgical and hydrometallurgical processes.
The pyrometallurgical process is made of several steps: roasting, smelting, converting, refining and
electro-refining.
The roasting is a major source of SO 2 emissions. During the roasting, the sulphides are heated to
become sulphur. The flue gases needs then to be desulphurized; they are usually direct ed to on-site
acid plants to produce sulphuric acid or liquid SO 2.
The smelting step enables the separation between copper sulphides from other compounds contained
in the ore. Roasting and smelting steps are realised in a unique furnace at high temperature s enabling
the separation between the matte mainly containing copper sulphides and the slag mainly containing
iron sulphides. [1].
The converting steps consist in injecting air and oxygen in the matte formerly obtained during the
smelting step. The converting processes can be batch, the most used, or continuous. During these
processes, SO2 emissions are also relevant.
The copper needs then to be refined; a fire refining process is first applied. During the fire refining
process, air is injected to the smelting metal so as to oxide the impurities and remove the last traces of
sulphur. A small reducing agent can be added but it increases NOx emissions.
The electro-refining process takes place in an electrolytic cell using a cast copper anode and a
cathode. The cell is placed in an electrolyte containing copper sulphate and sulphuric acid.
The hydrometallurgical process is mainly applied to oxide ores, oxide/sulphide ore s or ores hard to
concentrate. The ores are first crushed and then leached by sulphuric acid. The liquor produced
during the leaching is then clarified, purified and concentrated using a solvent extraction. Copper is
finally removed by electro-winning. It only differs from electro-refining in the anode form. [1].
Secondary production
The secondary copper is produced using pyrometallurgical processes. The steps of these processes
depend on the copper content of the secondary feed material. It can contain othe r organic material like
coatings. Therefore, secondary smelting and secondary refining are designed depending on the feed
material. [1].

7.9.2.3 BAT, Associated Emission Levels (AEL)

SO2:
In copper production, SO2 emissions cause the greatest concern. Sulphur comes mainly from the ores
used to produce copper. Hence SO2 emissions are more concerning during primary production than
during secondary production. Roasting, smelting and converting are the major sources of sulphur
dioxide. SO2 comes from the copper sulphides used to produce copper. The roasting and smelting
steps are realised in the same furnace. It needs to be sealed to enable a better collection of the gases.
Oxygen enrichment is used to produce high sulphur dioxide concentration. It enables the reduction of
the flue gas volumes. Sulphuric acid plants are used to convert these gases.
The converting process is also a source of SO 2 emissions, but the gas collection is not totally efficient
when using batch processes, due to the variation of sulphur dioxide concentration. Then SO 2 removal
systems need to be designed consequently. [1].
The sulphur dioxide emissions from the roasting, smelting and converting process are removed from
the flue gases using a sulphuric acid plant.
The following table gives an overview of achievable SO 2 emissions levels in copper production.
Table 4: associated SO2 emission levels with BAT to reduce emissions in copper industry [1]
[11]
Associated
emission level
with BAT
3
(mg/Nm )
SO2-rich off-stream gas (> 5 %)
99.7 – 99.92 %
Primary roasting, smelting and Double contact sulphuric acid plant
(conversion factor)
converting
Alkali semi-dry scrubber and fabric filter.
Wet alkali or double alkali scrubbers using
Secondary smelting and lime, magnesium hydroxide, sodium
converting, primary and secondary hydroxide.
< 50 – 200
fire-refining, electric slag cleaning Combinations of sodium or
and melting. alumina/aluminium sulphate in combination
with lime to regenerate the reagent and
form gypsum
Fabric filter with dry lime injection into a cool
gas < 500
Secondary fume collection
systems and drying processes Alkaline wet scrubber for SO2 collection
from hot gases (from dryer gases after dust < 50 – 200
removal)

NOx:
In copper production, the use of oxygen and the high temperature processes are responsible for NO x
emissions. During the primary production, nitrogen oxides are mainly absorbed in the sulphuric acid
produced. Thus NOx emissions are not a major issue. BAT to reduce these emissions are the use of
oxy-fuel burners and low NOx burners. [1].
The following table gives an overview of achievable NO x emissions levels in copper production. [1]
Table 5: associated NOx emission levels with BAT to reduce emissions in copper industry
Associated
emission level
Emission source Techniques with BAT
3
(mg/Nm )
primary and secondary Low NOx burner < 100

copper production Oxy-fuel burner < 100 - 300
Dust (including PM10, PM2.5 and BC):

In copper production, smelting, converting and refining processes are major sources of dust
emissions. In these production processes, flue gases are collected, cooled and filtered using ESP and
fabric filters to control dust emissions and volatile metals contained in dust. [1], [2].
This source is not identified as a large emitter of BC according to references [15], [16]. BC emission
data are scarce. According to [17], there is no BC emission in other non ferrous metal production.
The following table gives an overview of achievable dust emissions levels in copper production. The
preferred technique for dust abatement is the use of a fabric filter or a ceramic filter. Electrostatic
precipitators should be used for gases containing too much moist, for hot gases, or when the dust is
too sticky. Scrubbers should be used as the temperature or the nature of the gases precludes the use
of other techniques, or when gases or acids have to be removed simultaneously with dust.
Table 6: associated dust emission levels with BAT to reduce emissions in copper industry [1]
[3]
Associated emission level with BAT
Emission source Techniques 3
(mg/Nm )
Fabric filters
Smelting, converting and
ESP Dust: 1 – 5
refining processes
Scrubbers

7.9.3 Lead and Zinc

7.9.3.1 Coverage
This category covers both lead and zinc production, from primary and secondary production. These
metals are often associated together in ores and concentrates. As it is in the other non ferrous metal
processing industry, SO2 and dust emissions are the more concerning. However NO x emission
reductions are also detailed in this category.

As for copper or aluminium production, lead and zinc can be produced from primary or secondary
processes.
There are 2 primary lead production processes: the sintering/smelting process and the direct smelting
process. Primary zinc process is on the wane as a production method [6], [8].
The Sintering/smelting process involves of the agglomeration of lead and zinc concentrates,
recycled sinter fines, secondary materials and other process materials.
The agglomeration product is then crushed, screened and charged into an Imperial Smelting Furnace
where the smelting process takes place. Lead is directly recovered from this furnace as by product
and then refined. A mixing of zinc and lead is also recovered. Zinc needs to be separated from lead
before being refined [1].
The separation of zinc from lead takes place in a splash condenser in which a molten lead shower
enables the lead absorption. The resulting alloy is then cooled and zinc is recovered floating on the
surface. It is then refined.
In the direct smelting process, lead concentrates and other material are directly charged into the
furnace, melted and oxidised before being refined.
Secondary lead is produced from recycled lead wastes and scraps. Battery is a major source of lead.
Batteries can be crushed and separated into different fractions before going to the furnace . The lead
recovery process from automotive batteries starts with the drainage of the acid of the batteries before
further processing [10].
Lead contained in other material can be recovered using simple smelting processes [1].
There are 2 refining process for lead: the electrolytic refining and the pyrometallurgical refining.
The electrolytic refining is a high cost process, hence it is used where electricity is cheap (e.g.
hydroelectricity).
During the pyrometallurgical refining cells are heated, it enables the removal of the impurities. First
copper is removed by mechanical skimming, then arsenic, antimony and tin are removed by oxidation
associated with mechanical skimming [1].
The primary zinc obtained during the primary lead production is refined using a distillation process. It
enables during a first step the separation of zinc and cadmium from lead and during a second step the
separation of zinc from cadmium is realised. Finally zinc is treated with sodium to remove arsenic and
antimony.
In Europe, primary zinc is marginally produced from the primary lead process (~5%), it is essentially
produced from hydrometallurgical process. This process is used principally for treating zinc
sulphides, but also oxides, carbonates or silicates. It involves first the roasting of materials in fluidised
bed roasters, which produces sulphur dioxide and a calcine (zinc oxide). The Zinc calcine is then
cooled and leached by sulphuric acid. This process is similar to the copper hydrometallurgical
process. The Zinc solution obtained is then purified, refined and sent to the cellhouse. Here zinc is
extracted by means electrowinning [6].

Secondary zinc production, when treating metallic scrap, consists in physical separation, melting and
other high temperature treatment [1]. End-of-life galvanized products are recycled for steel recovery
and zinc oxide reports to fumes (Electric Arc Furnace (EAF)-dust) that are further treated
pyrometallurgically ( Waelz kilns or other furnaces) to recover a ‘Zinc oxide’ -rich fraction that is further
processed for zinc or zinc oxide recovery [6].
SO2:
During lead and zinc production process, the sulphur contained in materials is oxidised and sulphur
dioxide is emitted. Flue gases need then to be desulphurized. Sulphuric acid plants can be used,
where there is no pre-treatment of sulphur compounds, to convert these gases. Depending on the flue
gas SO2 content, a single or double contact sulphuric acid plant is considered as BAT to reduce
emission levels. Emissions from refining, material pre-treatment and secondary smelting are reduced
with SO2 scrubber. Wet alkaline scrubber or Alkali semi-dry scrubber and fabric filter is considered
BAT [1].
For secondary lead plants furnace feed materials can be desulphurized before smelting to reduce SO2
emissions and enable the plant to meet its emission limits [6].
The following table gives an overview of achievable SO 2 emissions levels in zinc and lead production.
Table 7: associated SO2 emission levels with BAT to reduce emissions in lead and zinc
industry [1] [11]
Associated
emission level
with BAT
3
(mg/Nm )
Low SO2 off-stream gas (< 5 %)
Single contact sulphuric acid plant or wet > 99.1 %
Primary roasting, smelting and
gas sulphuric acid plant. (conversion factor
sintering
SO2-rich off-stream gas (> 5 %)
99.7 – 99.92 % %
Primary roasting, smelting and Double contact sulphuric acid plant
(conversion factor)
sintering
Pre-treatment, secondary
smelting, thermal refining, melting Wet alkali scrubbers
< 50-200
secondary zinc processes and
slag fuming [9] Alkali semi-dry scrubber and fabric filter.
NOx:
In zinc and lead production, the roasting and the smelting processes are the main sources of NO x
emissions. Nitrogen oxides are mainly absorbed in the sulphuric acid produced during the primary
roasting, smelting and sintering flue gas treatment. Thus NO x emissions are not a major issue. BAT to
reduce NOx emissions at other process steps are the use of oxy-fuel burners and low NOx burners [1].
The following table gives an overview of achievable NO x emissions levels in zinc and lead production.

Table 8: associated NOx emission levels with BAT to reduce emissions in lead and zinc
industry [1]
Associated
emission level
with BAT
3
(mg/Nm )
Low NOx burner < 100
Lead and zinc production
Oxy-fuel burner < 100 - 300

The roasting and smelting processes are the major point sources of dust emissions for lead and zinc
industry. The gases need to be collected and treated to reduce dust emission levels. In these
production processes, flue gases are collected, cooled and filtered using ESP and fabric filters to
control dust emissions and volatile metals contained in dust. [1]. The preferred technique for dust
abatement is the use of a fabric filter or a ceramic filter. Electrostatic precipitators should be used for
gases containing too much moist, for hot gases, or when the dust is too sticky. Scrubbers should be
used as the temperature or the nature of the gases precludes the use of other techniques, or when
gases or acids have to be removed simultaneously with dust.
Emissions associated with the use of BAT to reduce dust emissions are presented in the following
table.
This source is not identified as a large emitter of BC according to references [15], [16]. BC emission
data are scarce. According to [17], there is no BC emission in other non ferrous metal production.
Table 9: associated dust emission levels with BAT to reduce emissions in lead and zinc
industry [1] [5]
3
(mg/Nm )
Fabric filters
Roasting and smelting Dust: 1 – 5
ESP

[1] Reference document on Best Available Techniques in the non ferrous metal industries,
December 2001.
[2] Assessments of technological developments BAT and limit value, non ferrous metal processing
industry, draft background document.
[3] UK fine particulate emissions from industrial processes, AEAT, August 2000.
[4] AP 42, Fifth edition, volume 1 chapter 12: metallurgical industry, EPA, January 1995.
[5] Characterization of particulate emissions from non-ferrous smelters, R.L Bennet and K.T
Knapp, JAPCA -February 1989
[6] Comments from Lynette Chung, EUROMETAUX, 02/2009.
[7] “Compilation of the answers-to-questions-and proposal of EGTEI secretariat.doc”,EGTEI,
02/2009.
[8] Comments from Aldo Zucca, PORTOVESME, 03/2009.
[9] Comments from Thomas Krutzler, UBA Austria, 03/2009.
[10] Comments from Ines Flügel, UBA Germany, 03/2009.
[11] Reference document on Best Available Techniques for the manufacture of large volume
Inorganic Chemicals – Ammonia, Acids and Fertilisers.
[12] EGTEI-State of progress.doc”, for WGSR, March 2009.
[13] Comments from Lynette Chung, EUROMETAUX, 05/2009
[14] Comments from André Peteers Weem, INFOMIL, 05/2009
[15] UNEP/WMO - Integrated Assessment of Black Carbon and Tropospheric Ozone – 2011
Particles in Europe and the Potential for their Control. International Institute for Applied S ystems

7.10 Cement production

7.10.1 Coverage
The emissions from cement plants which cause the greatest concern are nitrogen oxides (NO x) and
dust . Sulphur dioxide (SO2) emissions, are lower but are also considered in this guidance document.
This chapter covers installations for production of cement clinker in rotary kilns with a production
capacity exceeding 500 tonnes per day, or in other furnaces with a production capacity exceeding 50
tonnes per day [as it is the BREF document] [12].

The cement manufacturing process can be divided in 3 steps. The first step is the calcination, in which
calcium carbonate (CaCO3) is decomposed to form calcium oxide (CaO) at about 900 °C. The
following step is the clinker burning in which calcium oxide reacts with silica, alumina, and ferrous
oxides at about 1400 to 1500 °C to form the clinker, which is then cooled. Finally the clinker is ground
with gypsum and other additives to produce cement.
The clinkering process groups the calcination step and the clinker burning step. It is the largest source
of emissions in terms of NOx, SO2 and dust emissions. The clinkering process takes place in a kiln.
Most of the kilns used are rotary kilns. There are different processes used for the clinker production:
the dry process, the semi-dry process, the semi-wet process and the wet process. Preheater or
precalciner can be added to the process.
More than 75 % of the European clinker production is carried out with dry processes.
In the clinkering process, the raw meal is fed into the rotary kiln system where it is dried, pre-heated,
calcined and sintered to produce cement clinker. The clinker is then cooled and stored before being
mixed with gypsum to produce cement. [12].
Different preheating technologies are available for the clinkering process.
grate preheater takes place outside of the kiln. With grate preheater rotary kiln becomes
shorter, heat losses are reduced and energy efficiency is increased.
suspension preheating consists in maintaining the meal in suspension with flue hot gas from
the rotary kiln. The considerably larger contact surface enables almost complete heat
exchange, at least theoretically,
precalcination system divides the combustion in two points. The first burning occurs in the kiln
burning zone and the secondary burning takes place in a special combustion chamber between
the rotary kiln and the preheater.
The exhaust gases finally go through different cleaning devices to be dedusted and/or desulphurized.
[12].
Cogeneration can now be applied in cement plants. The excess heat from the cement production can
be used to generate electrical power [12].

If not stated otherwise, emission levels given in this section are expressed on a daily average basis
and standard conditions of 273 K, 101.3 kPa, 10% oxygen and dry gas.
SO2:
In cement production, SO2 emissions are mainly influenced by content of volatile sulphur in the raw
materials. Thus the main measure to reduce SO 2 emissions is the use of sulphur free fuel or fuel with
low sulphur content. SO2 emissions of cement kiln may be very low without any treatment of waste
gases: simply when low sulphur raw material and low sulphur fuels are used [10].

However, different flue gas cleaning systems can be used when initial SO2 emission levels are not
very low.
The addition of absorbents such as slaked lime (Ca(OH)2), quicklime (CaO) or activated fly ash with
high CaO content to the flue gas can absorb a portion of the SO 2, it is BAT. This injection can be
carried out under dry or wet form. The use of Ca(OH)2 based absorbents with a high specific surface
area and high porosity is recommended. The low reactivity of these absorbents implies to apply a
Ca/S molar ratio of between 3 and 6.
Wet scrubbing is BAT for desulphurization. In wet scrubbing technologies, the flue gas is first
dedusted then cleaned by an atomized solution of alkali compounds. SO 2 reacts with this solution to
form different by-products, which can be upgraded as sulphuric acid, sulphur, gypsum or scrubbing
agent. A SO2 reduction of more than 90 % can be expected.[12]
The BAT AEL can be met by applying absorbent addition or wet scrubber.
Regarding the absorbent addition it should be taken into account that the cost of
absorbents implies increasing operational costs for increasing SO2 concentrations, so that
this measure might not be cost effective anymore for initial SO2 emissions levels above 1.200 mg/m³.
3
In cement industry values in the range of 50-400 mg/Nm are expected when using adapted
technologies. The following table gives an overview of BAT associated SO2 emission levels for cement
manufacturing.
Table 1: BAT Associated SO2 emission levels to reduce emissions in cement Industry [12]
Associated
emission level
1
Parameters Techniques with BAT
3
(mg/Nm ) (daily
average value)
Absorbent addition
Sulphur in fuel SO2: <50 – <400
Wet scrubbing system
1
these values are daily average values and the range takes into account the sulphur content in the raw material
NOx:
In cement production, NOx emissions are influenced by different parameters: the type of fuel, the type
of combustion, the combustion air-ratio and the flame temperature. Thus, to reduce NOx emissions,
several measures can be taken.
Among primary measures, flame cooling, low NO x burners, staged combustion, mid kiln firing and
addition of mineralisers to the raw material are the main techniques used in cement plants :
Flame cooling can be achieved by an addition of water to the fuel or directly to the flame. It drops the
temperature and so limits NOx formation.
The addition of mineralisers, such as fluorine, to the raw material enables also the reduction of the
sintering zone temperature and thus NOx formation.
Low NOx burners enable to reduce NOx emissions during combustion processes. Combustion with
low NOx burner consists in a cold combustion with an internal or external flue gas recirculation. NO x
reductions up to 30% are achievable in successful installations and emission levels of 600-1000
3
mg/Nm have been reported with the use of this technology. Erreur ! Source du renvoi
introuvable.[12].
In staged combustion; the first combustion stage takes place in the rotary kiln. The second
combustion stage is a burner at the kiln inlet; it decomposes nitrogen oxides generated in the first
stage. In the third combustion stage the fuel is fed into the calciner with an amount of tertiary air. This
system reduces the generation of NOx from the fuel, and also decreases the NOx coming out of the

kiln. In the fourth and final combustion stage, the remaining tertiary air is fed into the system as 'top air'
for residual combustion. Staged firing technology can in general only be used with kilns equipped with
a precalciner [12].
Mid-kiln firing is applied in long wet or dry kilns. It creates a reducing zone by injecting fuel at an
intermediate point in the kiln system. In some installations using this technique, NO x reductions of 20 –
40% have been achieved.
Primary measures are efficient nevertheless secondary measures can be used to achieve larger NOx
emission reductions. Among them, selective catalytic reduction (SCR) and selective non-catalytic
reduction (SNCR) are the main techniques considered in cement plants [6]. In SNCR, the conversion
rate is lower: 10 – 50 % is obtained in cement plants.
In cement industry, the BAT for NOx emissions reduction are primary measures combined with staged
3
combustion or a SNCR. Emission values in the range of 200-500 mg/Nm are achievable when using
these technologies.
Selective Catalytic Reduction (SCR) is BAT, subject to appropriate catalyst and process developments
in the cement industry. Large reduction (85 – 95 %) can be expected. At least 2 suppliers in Europe
3
guarantee emissions in the range of 100-200 mg/Nm , when using this technique. However,
investment for this technique is still significantly higher than for SNCR [12].
The following table gives an overview of BAT associated NOx emission levels for cement
manufacturing [12].
If co-incineration waste is used, the requirements of the Waste Incineration Directive (WID) have to be
met [12].
Table 2: BAT Associated NOx emission levels to reduce emissions in cement industry [12]
Associated
emission level
with BAT
3
(mg/Nm )
Combination of: primary measures (flame cooling,
12
Preheater kilns low NOx burner, mid kiln firing, addition of <200 – 450
mineralisers...), staged combustion (also in
combination with a precalciner and the use of
optimised fuel mix), SNCR, SCR subject to
Lepol and long rotary 3
appropriate catalyst and process development in the 400 – 800
kilns
cement industry.
1
BAT-AEL is 500 mg/Nm3, where after primary measures techniques the initial NOx level is <1000mg/Nm3
2
Existing kiln system design, fuel mix properties including waste, raw material burnability can influence the ability to be in the
range. Levels below 350 mg/Nm3 are achieved at kilns with favourable conditions. The lower value of 200 mg/Nm3 has only
been reported as monthly average for three plants (easy burning mix used);
3
Depending on initial levels and ammonia slip.

In cement production, stack dust emissions come from three main sources; the kiln, the clinker cooler
and the cement mills. Diffuse emissions come from handling and storage of materials. The crushing
and grinding of raw materials and fuels handling can also be significant.
Cement production is not identified as a large emitter of BC according to references [17], [18] and [20].
However BC emission data are scarce.
Electrostatic precipitators (ESP) and fabric filters are used to control dust emissions in cement
production. If BC is present in dust, BAT measures described here after, which are efficient for fine
particles, are also efficient for BC.The fabric filter should have multiple compartments which can be

individually isolated in case of bag failure and they should be sufficiently designed to allow adequate
performance to be maintained if a compartment is taken off line. As the dust is collected the resistance
to the gas flow increases and so does the pressure inside the filter. There should be 'burst bag
detectors' on each compartment to indicate the need for maintenance when this happens.
3
Emissions below 5 mg/m can be achieved by well designed and well maintained fabric filters.
Sufficiently dimensioned electrostatic filters, with both good air conditioning and optimised ESP
3
cleaning regime, can reduce dust emission levels below 10 mg/Nm (daily average value).
Control of CO level is necessary for the use of ESP. Concentration of CO has to be kept below the
lower explosive limit to avoid any critical problem.
Roads used by lorries needs to be paved and periodically cleaned to avoid diffuse dust emissions. In
addition, spraying water at the installation site is used to avoid dust emissions. Chemical agents can
also be added to water to improve the efficiency of the agglomeration of dust. As far as possible,
material handling should be conducted in closed area, where air need to be collected and cleaned
through fabric filters [12].
In cement industry the BAT for dust emissions reduction are ESP and fabric filters. Concentration
3
values in the range of 5 – 50 mg/Nm of dust are achieved when using these technologies. With the
3
use of hybrid filters (combination of both FF and ESP), values in the range of 10 – 30 mg/Nm of dust
are achieved. The following table gives an overview of BAT associated dust emission levels for
cement manufacturing.
Table 3: BAT Associated dust emission levels to reduce emissions in cement Industry [4], [12]
3
(mg/Nm )
All kiln system
Clinker cooler
Fabric filters or ESP Dust: <10 – 20
Cement mills
1 Dry exhaust gas cleaning with a 2

Dusty operations Dust: <10
filter
1
It has be noted that for small sources (<10000 Nm 3/h) a priority approach has to be taken into account.
2
spot measurement, at least half an hour.

As in cement production, the most concerning emissions are NOx emissions, emerging techniques
presented are techniques to reduce NOx.
Fluidised bed combustion, and staged combustion combined with SNCR are emerging techniques to
reduce NOx emission levels.
3 3
Using fluidised bed combustion, NOx emissions vary from 115 mg/Nm to 190 mg/Nm when heavy oil
3 3
is used and from 440 mg/Nm to 515 mg/Nm when pulverised coal is used as fuel.
In theory, the combination of staged combustion and SNCR results in similar performance as SCR
technology in terms of NOx emission levels.

The following tables give an overview of the costs for different abatement techniques in cement
industry [12], [2].
Table 4: cost of techniques for controlling NO x in cement Industry [12]

1
Reported costs
Kiln systems Reduction Operating
Technique Investment
applicability efficiency 6 (euros/tonne of
(in 10 euros)
clinker)
Flame cooling All 0-35 % Up to 0.2 Up to 0.5
Low-NOx burner All 0-35 % Up to 0.45 0.07
Precalciner 0.1 – 2 0
Staged combustion 10-50 %
Preheater 1–4 0
Preheater and
30 – 90 % 0.5 – 1.2 0.1 – 1.7
SNCR Precalciner
Grate preheater 35 % 0.5 0.84
6
SCR Possibly all 43 – 95 % 2.2 – 4.5 0.33 – 3.0
1
Investment cost and operating cost in, referring to a kiln capacity of 3000 tonne clinker/day and initial emission up to 2000 mg
NOx/m3
6
Costs data based on a kiln capacity of 1500 tonne clinker/day
Table 5: cost of techniques for controlling SO 2 in cement Industry
Reported costs
Kiln systems Reduction Operating
Technique Investment
applicability efficiency (euros/tonne of
(in 106 euros)
clinker)
Absorbent addition All 60-80 % 0.2 – 0.3 0.1 – 0.4
Wet scrubber All > 90 % 5.8 – 23 0.5 – 2
2
Activated carbon Dry up to 95 % 15 No info.
2
This cost also includes an SNCR process, referring to a kiln capacity of 2000 tonne clinker/day and initial emission of 50-600
mg SO2/m3
Table 6: cost of techniques for controlling dust emissions in cement Industry [12].
1
Costs
Technique Applicability Investment Operating
6
(in 10 euros) (euros/tonne of clinker)
All kiln systems 2.1 – 6.0 0.1 – 0.2
Electrostatic clinker coolers 0.8 – 1.2 0.09 – 0.18
precipitators
cement mills 0.8 – 1.2 0.09 – 0.18
All kiln systems 2.1 – 6.0 0.15 – 0.35
Fabric filters clinker coolers 1.0 – 1.4 0.1 – 0.15
cement mills 0.3 – 0.5 0.03 – 0.04
1
Investment cost and operating cost to reduce the emission to 10-50 mg/m3, normally referring to a kiln capacity of 3000 tonne
clinker per day and initial emission up to 500 g dust/m3

7.10.6 References used in the chapter 7.10
[1] Aerosol size distribution determination from stack emissions: the case of a cement plant,
Fraboulet, 2007. Dust conference in Maastricht. April 2007.
[2] Background document: cement production, EGTEI, 2003.
[3] Assements of technological developments BAT and limit value, cement industry, draft
background document.
[4] Options for updating BAT from a technical point of view and implications for other annexes, M.
Suhr, FEA Germany, Task Force on Heavy Metal, june 2008.
th
[5] Ministère de l’écologie – France - “Arrêté du 3 mai 1993”, JO 15 june 1993.
[6] Comments from André Peeters Weem, Cees Braams, InfoMil, the Dutch Ministry of
Environment, 12/2008.
[7] Comments from Maja Bernicke, Federal Environment Agency Germany, 12/2008.
[8] Comments from Gaston Theis, Swiss Federal Office for the Environment, 11/2008.
02/2009.
[11] “EGTEI-State of progress.doc”, for WGSR, March 2009.
[12] European Commission - Reference document on Best Available Techniques in the cement, lime
and magnesium oxide manufacturing industries, May 2010.
[13] Comments from CEMBUREAU, May 2010.
[14] Comments from EULA, May 2009
[15] Comments from Andre Peteers Weem, INFOMIL, May 2009
[16] Comments from Maja Bernicke, UBA, May 2009
[20] EPA – Report to congress on black carbon – March 2012

7.11 Lime production

7.11.1 Coverage
This category covers the lime production and the use of lime kiln in lime industry. It does not cover the
lime kiln integrated in other industrial process such as in paper industry.
The emissions from lime plants which cause greatest concern are dust (TSP) emissions. Lime
production process is also a source of nitrogen oxides (NOx) and sulphur dioxide (SO2) emissions.
These emissions mainly arise from the limestone calcining process [7].

Lime is produced by a heating process. Calcium or magnesium carbonate is heated to form carbon
dioxide and lime. During this process, NOx, SO2 and dust are emitted.
Different techniques are used for lime production. The choice of the technique depends on the
quantity of lime to be produced and the size of the feed stones.
Most of used furnaces are based on either the shaft or the rotary design. All of these designs
incorporate the concept of three zones: the preheating zone where limestone is heated to 800°C, the
calcining zone where the combustion takes place and enable the formation of lime at over 900°C,
and the cooling zone where lime is cooled. The lime which exits from the cooling process is called
quicklime (CaO).
Some rotary and fluidised bed kilns, are operated in connection with separate preheaters.
Quicklime from the cooling process is screened and fines particles, less pure, are removed. The
screened quicklime is then crushed and classified to control the grading of the products.
Slaked lime can also be produced. It includes hydrated lime, milk of lime and lime putty. Hydrated lime
is produced from quicklime using a hydrator. Milk of lime and lime putty are produced by sla king of
lime in excess of water. Batch and continuous slakers are used for this operation [7].

If not stated otherwise, emission levels given in this section are expressed on a daily average basis
and standard conditions of 273 K, 101.3 kPa, 11% oxygen and dry gas.
SO2:
In lime production, SO2 emissions are influenced by the sulphur content of the fuel used during the
combustion process. SO2 emissions also depend on the design of kiln and the required sulphur
content of the lime produced. The main measure to reduce SO2 emissions is the use of free sulphur
fuel or fuel with low sulphur content. There is no secondary measure considered in the current BAT to
reduce SO2 emissions. Absorbent addition techniques are available, but not currently applied.
SO2 from the flue-gases of kiln firing processes can be reduced by using process optimisation
measures/techniques to ensure an efficient absorption of sulphur dioxide, i.e. efficient contact between
the kiln gases and the quicklime.
As no BAT emission levels are available, Ttypical SO2 emissions associated with the use of BAT from
lime production are presented in the following table [7].
5 July 2012 Page 135

Table 1: associated SO2 emission levels with BAT to reduce emissions in lime Industry [7]
Associated emission
Emission source Techniques level with BAT
3 1, 2
(mg/Nm )
Parallel flow regenerative kiln (PFRK),

annular shaft kiln (ASK), mixed feed shat Combination of: process
<50 – <200
kiln (MFSK), other shaft kiln (OSK) and optimisations to ensure an efficient
preheater rotary kiln (PRK) absorption of SO2, use of fuel with
low sulphur content and using
Long rotary kiln (LRK) absorbent addition techniques < 50 – < 400
1
The level depends on the initial SOX level in the exhaust gas and on the reduction measure technique used
2
For the production of sintered dolime using the “double pass process”, SOx emissions might be higher than the upper end of
the range.
NOx:
In lime production, NOx emissions are influenced by different parameters: the type of fuel, the type of
combustion, the combustion air-ratio and the flame temperature. Those parameters depend on the
quality of lime to be produced and the design of kiln.
Both primary and secondary measures can be used in order to reduce NO x emissions. Primary
measures include:
process optimization: smoothing and optimising the plant operation and/or homogenisation of
the fuel and raw material feedings.
burner design: NOx emissions can be minimised by the operation of special low NO x burners.
These burners are useful for reducing the flame temperature and thus reducing thermal and (to
some extent) fuel derived NOx. The NOx reduction is achieved by supplying rinsing air for
lowering the flame temperature or pulsed operation of the burners. Low NO x burners are only
applied to rotary kilns.
Secondary measure that can be applied is:

selective non catalytic reduction (SNCR): in the selective non-catalytic reduction (SNCR)
process, nitrogen oxides (NO + NO2) from the flue-gases are removed by selective non-catalytic
reduction and converted into nitrogen and water by injecting a reducing agent into the kiln
which reacts with the nitrogen oxides. The reactions occur at temperatures of between 850 and
1020 °C, with the optimal range is typically between 900 to 920 °C. In lime manufacturing,
SNCR is applicable to preheater rotary kilns (Lepol grate). For vertical kilns, it is technically not
yet feasible to carry out an SNCR treatment since the temperature of the flue-gas is far below
200 °C. In long rotary kilns, the application of the SNCR technology is not practical as the zone
with the optimal window of temperatures is located within the rotating part of the kiln. Being an
emerging technique in the lime industry, SNCR is currently only applied in one plant in Europe.
As no BAT emission levels are available, Ttypical NOx emissions associated with BAT from lime
production process are presented in the following table [7].

Table 2: associated NOX emission levels with BAT to reduce emissions in lime Industry [7]
Associated emission
Emission source Techniques level with BAT
3
(mg/Nm )
Annular shaft kiln (ASK), parallel flow Combination of: primary 12

regenerative kiln (PFRK), mixed feed shat techniques (use of fuel with low 100 – < 350
kiln (MFSK) and other shaft kiln (OSK). nitrogen content, process
optimisations, burner design (low
Long rotary kiln (LRK) NOX burners), air staging (PRK)) 13
and SNCR (lepol rotary kiln). < 200 – < 500
Preheater rotary kiln (PRK)
1The higher ranges are related to the production of dolime and hard burned lime.
2
For LRK and PRK with shaft producing hard burned lime, the upper level is up to 800 mg/Nm3.
3
Where primary measures/techniques are not sufficient and where secondary measures/techniques are not available to reduce
NOx emissions to 350 mg/Nm3, the upper level is 500 mg/Nm3, especially for hard burned lime.

In lime production, the kiln and the post-cooling processes are the main sources of dust emissions.
Fugitive emissions from handling and storage of materials are also significant.
Rotary kilns are generally equipped with ESP while shaft kilns and lime grinding plants are equipped
with fabric filters to control dust emissions. Fabric filters should be equipped with burst bag detectors
to indicate the need for maintenance.
Cyclones can also be used to reduce dust emissions but only as flue gases pre-cleaners. Cyclones
are easy to operate and cost effective but do not retain effectively microparticles and not avoid the use
of ESP or FF.
Flue gases from lime hydrating can be dedusted using wet scrubbers or fabric filters while flue gases
from lime grinding can be dedusted using both cyclones and fabric filters.
Lime production is not identified as a large emitter of BC according to references [11], [10] and [13].
However BC emission data are scarce.
If BC is present in dust, BAT measures described here above, which are efficient for fine particles, are
also efficient for BC.
The following table gives an overview of achievable dust emissions levels in lime manufacturing.

Table 3: Associated dust emission levels with BAT to reduce emissions in lime Industry [7]

(mg/Nm )
34
ESP Dust: < 20 Mis en forme : Exposant
Kilns
4
Fabric filters Dust: < 10
2
Fabric filter Dust: <10
1
Dusty operations
Wet scrubbers 2
Dust: < 10 – 20
(mainly used in hydrating plants)
1
It has be noted that for small sources (<10000 Nm3/h) a priority approach has to be taken into account.
2
Values are given as the average over the sampling period (spots measurements, for at least half an hour)
3
In exceptional cases where resistivity of dust is high, the BAT AEL could be higher, up to 30 mg/Nm3, as the daily average
value.
4
Daily average values.

Considered emerging reduction techniques in lime production are:
fluidised bed calcinations to reduce SO2 and NOx emission levels.
absorbent addition (hydrated lime or sodium bicarbonate) to reduce SO2 emission levels. This
process needs an optimised residence time to be effective.
ceramic filters to reduce dust emission levels. They are not currently used but their ability to
reduce dust at high temperature makes this technique available.

As dust emissions are the emissions which cause the greatest concern, costs of reduction techniques
are only presented for dust Erreur ! Source du renvoi introuvable.[7], [2][7], [2]. There are three Mis en forme : Anglais (États Unis)
main dedusting techniques used for lime kilns : fabric filters, electrostatic precipitators (ESPs) and wet
scrubber.
Investments costs are affected by the size of the filter and the operating conditions. Therefore, a wide
variation of investment costs exists. The main cost drivers are investments, maintenance and energy.
The cost of dust reduction techniques are presented in the next table.

Table 4: cost of techniques for controlling dust in lime Industry
Emission level Cost

3
Technique Applicability 3 1 2
mg/m kg/tonne investment operating
All kiln systems,
ESP milling plant, <10 – <20 0.015 – 0.1 0.6 – 3.9 >1.5
subsidiary processes
All kiln systems <10 – <20 0.015 – 0.15
Fabric filter Milling plant, 0.25 – 1.7 >1.5
<10 – <20 0.015 – 0.05
subsidiary processes
Wet dust All kiln systems,
10 – 30 0.06 – 0.25 - -
separator hydrating plants
1
normally referring to daily averages, dry gas, 273 K, 101.3 kPa and 11% O2, except for hydrating plants for
which conditions are as emitted.
2 3 3
kg/tonne lime based on 3 700 Nm /tonne of lime for rotary kilns with preheaters, 3 000 Nm /tonne of lime for
3
annular shaft kilns and parallel flow regenerative kilns and 5 000 Nm /tonne for long rotary kilns
3 6 Mis en forme : Exposant
investment in 10 euros and operating cost in euros/tonne lime, referring to different kiln capacities.

[1] Auswertung von staub- und Feinstaubemissionsdaten der Datenbank nordrhein-westfälisher
Emissionserklärungen, LUA NRW, 2003.
[2] Background document: lime production, EGTEI, 2003.
[3] Comments from André Peeters Weem, Cees Braams, InfoMil, the Dutch Ministry of
Environment, 12/2008.
[4] Comments from Maja Bernicke, Federal Environment Agency Germany, 12/2008.
[5] Comments from Gaston Theis, Swiss Federal Office for the Environment, 11/2008.
[6] “Compilation of the answers-to-questions-and proposal of EGTEI secretariat.doc”, EGTEI,
02/2009.
[7] European Commission - Reference document on Best Available Techniques in the cement, lime
and magnesium oxide manufacturing industries. May 2010
[9] Comments from Mira Tayah, IMA, May 2009.
Particles in Europe and the Potential for their Control. International Institute for Ap plied Systems


7.12 Glass production

7.12.1 Coverage
The sector of glass production includes installations for the manufacture of glass with a melting
capacity exceeding 20 tonnes per day. The production of glass fibres and mineral fibres is dealt with
in the chapter “Man-Made Fibres” (7-13) This sector includes the manufacture of flat glass and
container glass, as well as the production of special glass (TV screen, lighting), domestic glassware
and water glass. The production of flat, container and commodity glass is dominated by large
multinational companies, whereas the manufacture of table and decorative ware is mainly composed
of small and medium sized enterprises. Unlike the production of technical glass, domestic glass
production is characterized by a great diversity of products and processes, including hand forming of
glass [1],[1], [2], [3].

As glass making is an energy intensive activity, the choice of energy source, heating technique and
heat recovery are crucial for the environmental performance of an installation. Natural gas, fuel oil and
electricity are the three main energy sources. While in the recent decades, fuel oil has been the
predominant fuel for glass making, the use of natural gas is increasing due to the ease of control and
reduced emissions of SO2 and CO2, however generally at higher cost. Many furnaces are today
equipped to run on both natural gas and fuel oil with a fuel change-over only requiring a change of
burners; a mixing of fuel and gas in the same burner is also found. Electricity (resistive heating, where
a current is passed through the molten glass) is the third energy source for glass making; it can be
used either as the exclusive energy source or in combination with other fuels [1][1].
Manufacturing techniques vary from small electricity heated furnaces to cross-fired regenerative
furnaces in the flat glass sector, producing up to 900 tonnes per day [4][4]. The following list contains
the main melting techniques for different classes of capacities:
large capacity (>500 t/d) installations: Almost always cross-fired regenerative furnaces
medium capacity (100 to 500 t/d) installations: regenerative end-port furnaces are favoured,
but cross-fired regenerative, recuperative unit melters and also oxy-fuel and electric melters
may be used
small capacity (25 to 100 t/d) installations: Recuperative unit melters, regenerative end port
furnaces, electric melters and oxy-fuel melters are used [1].[1].
Regenerative furnaces utilize regenerative systems for heat recovery and usually burners in or below
combustion air / waste gas ports. Waste gas heat is used to preheat combustion air by passing the
waste gas through a heat absorbing chamber. The furnace fires on one side at a time and after about
twenty minutes, the firing is reversed and the combustion air is passed through the previously heated
chamber. Preheat temperatures up to 1400°C and very high thermal efficiencies may be reached.
Regenerative furnaces are either cross-fired (combustion ports and burners along the sides of the
furnace, chambers on either side) for rather large installations or end-fired (burners and chambers on
one side).
Recuperative furnaces utilize heat exchangers for heat recovery, which continuously preheat the
combustion air by the waste gases. Temperatures are limited to around 750°C for metallic
recuperators and the specific melting capacity of recuperative furnaces is around 30% lower than for
regenerative furnaces. The burners are located along each side of the furnace and fire continuously
from both sides. Recuperative furnaces are primarily used when high flexibility of operation is required
with minimum initial capital, and when regenerators are not economically viable due to small capacity.
Oxy fuel melting involves the replacement of combustion air with oxygen (>90% purity), by which the
volume of waste gas is reduced by about two thirds. As the atmospheric nitrogen has not to be heated
to the flame temperature, energy savings are possible, as well as reduction of NO X formation. This

kind of furnace generally has the same design as unit melters (multiple lateral bur ners, a single waste
gas exhaust port), but does not utilize heat recovery systems to pre-heat the oxygen supply.
Electric melting uses a refractory lined box with electrodes inserted either from the top, the sides or,
more usually the bottom of the furnace. Energy is provided by resistive heating, as the current passes
through the molten glass. The technique is commonly applied in small furnaces (especially for special
glass), the upper size limit for the economic viability is determined by the cost of ele ctricity compared
to fossil fuels. The replacement of fossil fuels in the furnace eliminates the formation of combustion by-
products.
Combined fossil fuel and electric melting can be either fossil fuel firing with electrical boost or (less
common) predominantly electrical heating with a fossil fuel support.
Discontinuous batch melting is used when smaller amounts of glass are required, particularly if the
glass formulation changes regularly. Pot furnaces or day tanks are used to melt specific batches of
raw material, most of them are below the sector threshold of 20 tonnes/day. A pot furnace uses a
lower section to preheat the combustion air and an upper section, which holds the pots, serves as the
melting chamber. Day tanks are larger and resemble a conventional furnace, but are refilled with batch
each day.
Special melter designs were developed to improve efficiency and environmental performance[1][1].
The major environmental challenges for the glass industry are emissions to air and energy
consumption. Glass making is a high temperature, energy intensive activity, resulting in the emission
of combustion products and the high temperature oxidation of atmospheric nitrogen, i.e. in particular
sulphur dioxide, carbon dioxide, and oxides of nitrogen. Furnace emissions also contain dust, which
arises mainly from the volatilisation and subsequent condensation of volatile batch materials [4].

7.12.3.1 SO2
The main techniques for controlling SO2 emissions are fuel selection, batch formulation and acid gas
scrubbing. For oil-fired processes, the main source of SO 2 is the oxidation of sulphur contained in the
fuel. SO2 emissions from the batch vary depending on the use of mainly sodium sulphate for glass
oxidation and in some cases sulphite/sulphide in raw materials, but are lower than those from fuel
whenever oil-firing is used. The most obvious way for reducing SO 2 emissions is thus to reduce the
sulphur content of the fuel or to switch to gas-firing (essentially sulphur free). While the use of fuel with
lower sulphur content does not necessarily lead to higher cost (except higher fuel price), the switch to
gas-firing requires different burners and several other modifications. It is considered BAT to use gas or
oil with a sulphur level of 1% or lower, burning higher sulphur content fuel may also represent BAT if
abatement is used to achieve equivalent emission levels [1],[1], [9].
Concerning emissions from batch materials, sulphates are the main source for conventional glass
making, as they are the most widely used fining agents and are also important oxidising agents. In
most modern glass furnaces, batch sulphates have been reduced to the minimum practicable level.
Concerning scrubbing, the principles of dry and semi-dry scrubbing are the same: the absorbent is
introduced to, and dispersed in the waste gas stream, the absorbents chosen for SO 2 are also
effective for other acidic gases. The absorbent can be a dry powder (dry process), a suspension or
solution with the water-cooling the gas stream (semi-dry process). The recycling of filter dust
(including sulphate waste) is often considered reasonable, when technically applicable. This measure
can reduce sulphur overall emissions up to the technically feasible substitution in raw materials by
filter dust; external disposal routes for the filter dust may be additionally necessary. Thus site -specific
solutions may include a balancing of potentially conflicting waste minimisation and sulphur emissions
reduction, a process sulphur balance will be essential in this case.
The majority of installed SO 2 scrubbers operate with dry-lime scrubbing at around 400°C, at this
temperature a SO2 reduction of about 50% can be achieved (higher reduction rates possible for
around 200°C and humid atmosphere) [1],[1], [5].

For container glass, flat glass, domestic glass and special glass, secondary abatement for dust
with dry or semi-dry acid gas scrubbing where appropriate is considered as BAT. Different values are
given for BAT depending on the fuel and (for container glass and flat glass) on the emission reduction
priority of the installation, as waste minimisation by filter dust and cullet recycling may lead to higher
SO2 emissions.
For frits, BAT for SO2 is considered to be fuel selection (where practicable) and control of batch
composition [1] [1].
Table 1: SO2 emission levels associated with BAT for furnaces in glass production [1][1]
1
BAT associated emission levels
3
Emission source mgSO2/Nm or (kg/tonne) Comments
gas-firing oil-firing
Container glass with SO2 200 – 500 500 – 1200
reduction as priority (0.3-0.75) (0.75-1.8)
Container glass with Where mass balance does not allow
< 800 < 1500
waste minimisation as the figures above to be achieved.
priority (1.2) (2.25)
Flat glass with SO2 200 – 500 500 – 1200

reduction as priority (0.5-1.25) (1.25-3)
Where mass balance does not allow
Flat glass with waste < 800 < 1500
the figures above to be achieved.
minimisation as priority (2) (3.75)
If low sulphate in batch, then <200 for

Domestic glass 200 – 500 500 - 1300 gas-firing.
(0.5-1.25) (1.25-3.25) Figures in upper part of ranges relate
to dust recycling.
Special glass (including Figures in upper part of ranges relate
200 – 500 500 - 1200
water glass) to dust recycling.
< 200 Oil firing is rare.
Frits 500 - 1000
(0.1-0.5)
1
The BAT associated emission levels are based on a daily average, standard conditions and represents a typical load
situation. For peak load, start up and shut down periods, as well as for operational problems of the flue gas cleaning
systems, short-term peak values, which could be higher, have to be regarded.
For combustion gases: dry, 8 % oxygen by volume (continuous melters), 13 % oxygen by volume (discontinuous
melters). For oxy-fuel fired systems the expression of the emissions corrected to 8 % oxygen is of little value, and
emissions from these systems should be discussed in terms of mass.

7.12.3.2 NOx
In glass production, nitrogen oxides are mainly generated as thermal NO X caused by high furnace
temperatures, as a product from decomposition of compounds in the batch materials, and from the
nitrogen contained in the used fuels. Thus several parameters have a significant influence on the NOX
emission levels: the type and amount of fuel used (natural gas, heavy fuel oil), the furnace t ype (cross-
fired, end-fired furnaces; regenerative, recuperative air preheating), the melting temperature and the
type of glass produced [1], [2]. The most appropriate techniques for controlling NO X emissions are in
general: primary measures, oxy-fuel melting, chemical reduction by fuel, selective catalytic reduction
(SCR) and selective non-catalytic reduction (SNCR) . When using oxycombustion, special care has to
be taken with regard to energy efficiency so as not to reduce the NO X emission abatement potential
[1],[1], [6].
Primary process modifications are based on the following techniques or combinations: reduction of the
1
air/fuel ratio (near stoichiometric combustion), staged combustion , low NOX and sealed burners and
fuel change. Further measures include the running of furnaces under slightly reducing conditions and
to minimize the combustion air supply. The latter is done in order to enhance energy efficiency and to
prevent NOX formation. It is generally recommended to maintain 0,7-1 % O2 in unit melters and 1-2%
O2 in end-port furnaces (measured at combustion chamber exit) and to keep the CO level as low as
possible (200-300 to 1000 ppm CO maximum)[8], [9].
Secondary techniques for reducing NOX emissions in glass manufacturing should be implemented
where primary measures do not achieve necessary NO X levels. They include the chemical reduction
by fuel, the use of selective catalytic reduction (SCR) and, not widely adopted, the use of selective
non-catalytic reduction (SNCR), [9].
For container glass, the main techniques likely to be considered BAT are primary measures
(combustion modifications), oxy-fuel firing, SNCR or SCR (other techniques that achieve the emission
levels may also represent BAT). Technically, low NO X levels can be achieved using for example the
special melters or electric melting. However, these techniques may only be economically applicable i n
certain circumstances. More widely applicable but options, which may not represent the most
appropriate option in all circumstances are oxy-fuel firing and batch/cullet preheating.
Where these secondary techniques require a delay until the next rebuild, many air fuel fired furnaces
are expected to achieve emission levels of 600-850 mg/Nm³ with primary measures only.
For flat glass BAT are primary measures. When other techniques (e.g., SCR,) can be used to achieve
the given levels, they can also be considered BAT. Where these techniques require a delay until the
next rebuild, many air fuel fired furnaces are expected to achieve emission levels of <850 mg/Nm³ with
combustion modifications only.
For domestic glass, BAT statements are more difficult, as in the sector high product quality
requirements, lower production volumes and more oxidising conditions (higher levels of nitrate)
increase the potential for NO X emissions. For smaller installations, electrically heated furnaces are an
option and are considered BAT for lead crystal, crystal glass and opal glass.
In the short time, using primary combustion measures, emission reductions of up to 40% compared to
the current levels are expected. As a medium term proposal, values in the range of 500 -700 mg/Nm³
are expected using the following measures (or combinations thereof) that are considered BAT: primary
measures, oxy-fuel-firing or SCR (if costs are acceptable).
For special glass, the BAT values are based primarily on the use of oxy-fuel melting and SNCR or
SCR. The sector is very diverse and the appropriate technique will depend on site-specific issues.
For frits, BAT is the use of oxy-fuel melting or alternatively the use of air-gas systems and primary or
secondary measures that are able to achieve the given levels [1].[1].
1
This measure is expected to be phased out with the installation of new low-NOx burners

Table 2: NOX emission levels associated with BAT for furnaces in glass production [1]. [1]
BAT associated
Combination of emission levels
1
Emission source Comments
control measures 3
mg/Nm (kg/tonne)
BAT techniques (see Transition until next rebuild
500-700 (1.5-1.75)
Flat glass text) or substantial use of nitrate
compounds: < 850 (2.2)
BAT techniques (see Transition until next rebuild:
Container glass 500-700 (0.5-1.1)
text) 500-850 (0.9-1.3)
BAT techniques (see

Special glass 500-700
text)
Electrical heating (0.2-1.0)
Short term
Domestic Glass (Lead modifications: Air-fuel 1000-1500 (2.5-3.5)
crystal, crystal glass, opal fired
glass) Medium term limit
values: Primary
500-700 (0.5-1.75)
measures, oxy-fuel,
SNCR, SCR
Oxy-fuel melting (0.5-1.5)
Frits Air-gas systems and
primary / secondary 500-700
measures
1
systems, short-term peak values, which could be higher, have to be regarded.

Dust is emitted by all sub-sectors of glass manufacturing in different process steps. Dust emissions in
glass manufacturing industry stem mainly from furnaces and to a lesser extent from batch mixing (use
of powdered, granular, or dusty raw materials) and finishing and blasting of glass products. Dust is
emitted by the batch plant as volatile components that evaporate and condensate from the batch and
the glass melt (mainly sodium sulphate), by combustion of some fossil fuels, in low quantities by
materials transportation, handling, storage, and mixing. Dust emissions depend notably on the type of
fuel used, the furnace type, and the type of glass produced. Besides end-of-pipe measures,
possibilities to slightly reduce direct dust emissions are: pelleting the glass batch, changing the
heating system from oil/gas-firing to electrical heating, charging a larger share of glass returns in the
batch, and applying a better selection of raw materials (size distribution) [2].
Dust emissions arising through transportation, storage and mixing are typically coarser than those
2
from the high temperature processes, which are generally < 1µm. Emissions from storage can be
reduced by using enclosed silos, which are vented to suitable dust abatement equipment. During
transportation by above ground conveyors, some type of enclosure to provide wind protection is
necessary to prevent substantial material loss. These systems can be designed to enclose the
conveyor on all sides. Where pneumatic conveying is used, it is important to provide a sealed system

with a filter to clean the transport air before release. To reduce dust during conveying and "carry-over"
of fine particles out of the furnace, a percentage of water can be maintained in the batch, usually 3 -
4 % [2].
During the melting cycle using discontinuous furnaces, the dust emission varies greatly. The dust
emissions from crystal glass tanks (<5 kg/tonne melted glass) are higher than from other tanks (<1
kg/tonne melted soda and potash glass). Oxy-fuel burners can reduce waste gas volume and flue dust
production by 60%. The most significant means for reducing dust emissions from furnaces is the use
of either an electrostatic precipitator or a bag filter system, were appropriate in combination with a dry
or semi-dry acid gas scrubbing system. Installation of electrostatic precipitators (ESP) can reduce dust
3 3
emissions to 30 mg/m and fabric (baghouse) filters can reduce the emissions below 10 mg/m . The
BAT emission level with these techniques is 5-30 mg/Nm³ (equates to 0.1 kg/tonne of glass melted),
based on a typical averaging period between 30 minutes and 24 hours. In some cases, BAT for metal
emissions may result in lower emission levels for dust [1],[1], [2].
For container glass, flat glass, domestic glass, special glass, frits BAT for dust is considered the
use of an electrostatic precipitator or bag filter operating, where appropriate, in conjunction with a dry
or semi-dry acid gas scrubbing system. The application of BAT for metals may in some cases result in
lower emission levels for dust [1]. [1].
The production of glass is not identified as a major source of black carbon, according to references
[12], [13] and [15]. However BC emission data are scarce. BC emissions are linked to incomplete
combustion. This type of situation does not occur in glass production which is a continuous process
with high level of energy efficiency. Reference [14] provides an emission factor of 0.06 % of TSP. If
BC is present in dust, BAT measures described just above, efficient for fine particles, are also efficient
for BC.

Table 3: dust emission levels associated with BAT for furnaces in glass production [1][1]
1
Emission source 3 Comments Commentaire [CITEPA1]: Colunm to
mg/Nm or (kg/tonne) be deleted
Container glass 5-30 (<0.1)
Flat glass 5-30 (<0.1)
Domestic glass 5-30 (<0.1)
Special glass 5-30
Frits 5-30 (<0.1)

1
7.12.3.4 VOC
VOC emissions from the production of mineral fibres are subject of the section on “man -made fibres”
(chapter 7-13). For other glass manufacturing operations, minor emissions of VOCs could also arise
for example from cold coating operations. These emissions are not considered to be very significant
and are not discussed further.

For the sector of glass production, the recycling of filter dust (including sulphate waste) may lead to
higher SOX emissions, thus waste minimisation and sulphur emissions reduction may become
conflicting targets (cf.refer to chapter 7.12.3.1).

In the medium term, no major breakthroughs in technology are expected. Techniques that are already
beyond the state of emerging technologies, but which are likely to undergo further development are
low NOX burner systems, oxy-fuel melting, cullet and batch preheating, developments concerning
batch formulations, the integration of frit processes. Innovative long-term techniques still at pilot scale
are systems using ceramic filters and catalysts combining in one operation NOx, SOx and Dust
removal (CERCAT®) and ESP using charged water droplets (TRI-MER®) [1],[1], [10].


Table 4: cost data for different abatement techniques [1],[1]
Abatement Capital Costs [k€] Annual Operating Costs Specific cost [€/Tonne
Technique @ 100/300/600 [k€] @ 100/300/600 molten glass]
[Tonnes/d] [Tonnes/d] @ 100/300/600 [Tonnes/d]
SCR 615/1000/1800 64/123/330 4.98/2.83/2.99
SNCR 280/450/1350 28/73/225

2.35/1.49/2.16
LowNOx 100/180/550 21/35/72

1.34/0.72/0.83
Oxy-Fuel -300/-1350/-4800 190/530/1900 4.06/5.05/5.16
3R incl. Repair etc - /270/680 - /185/285 2.87/2.28/1.91
3R excluding repair - /140/260

- /106/267 2.20/1.35/1.50
SCR+filter 1500/2420/4550 10.2/5.75/5.78

108/200/470
Filter+scrubber 875/1420/2750 53/89/186 5.52/3.01/3.06
Values for a capacity of 100 [tonnes/day] Container (11120 m³ flue/h), 300 [tonnes/day] Container
(23000 m³ flue/h), 600 [tonnes/day] Float (70000 m³ flue/h)
Table 5: efficiencies of different NOX reduction technologies in Glassmaking [5]
Achieved reduction Secondary measures Achieved reduction
Low-NOx burner 40% 3R process 85%
Staged combustion 35% SCR >70%
Oxy-fuel firing <1kg NOX/tonne glass SNCR Up to 70%

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including PM10, PM2,5 and black carbon) from stationary sources
Table 6: specific cost for different combinations of filters (dust) and scrubbers (SOX) for glass furnaces [11]
ESP & dry ESP & dry ESP & dry ESP & dry Bag filter & Bag filter & Bag filter & Bag filter &
Production scrubber scrubber scrubber scrubber dry dry semi dry semi dry
scrubber Wet
Type of (CaOH)2 (CaOH)2 (NaHC03) (NaHC03) scrubber scrubber scrubber
(Tons melt scrubber
glass Filter dust
per day) Filter dust Filter dust Filter dust Filter dust Filter dust Filter dust Filter dust [€/t]
disposal
recycle [€/t] disposal [€/t] recycle [€/t] disposal [€/t] recycle [€/t] [€/t] recycle [€/t] disposal [€/t]
9.6 (gas)-13
Float 500 4.8 6.51 6 7-7.35
(oil)
Float 700 4.27 5.87 4.39 7.75 6.98
Float 900 3.88 5.44 5.82 8.33
Container 100-150 11 14
Container 200 6.7 4.63-5.9 4.8-7
Container
200 6.4 9.25
(oil)
Container
300-350 4.52-6 6.31-7.5 7.38-8.33 3.86-5 4.11-7.3 5.3 6.54
(oil)
Container 450 3.96-5.2 4.77-6.5 2.9 3.6
Container
600 3.58 5.1 2.7 3.37
(oil)
Container
740 4 5.1
(gas)
Container
1240 3.4 4.6
(gas)
Container
1240 3.7 6.2
(oil)
Tableware 30-35 15.65 16.7 12.85 13.84
Tableware 180-200 7.66 3.75-4.35
E-glass oxy 100-120 11 14.4-21.5*
E-glass air 100-120 15.7-20.5*
* higher value for filter dust disposal 400 Euro/ton
Table 7: specific cost for different DeNOx methods for glass furnaces [11]
Production Basic Lownox All-Oxygen firing All-Oxygen firing

SNCR Extended
(€/Nm³) with (€/Nm³) with
Type of glass (Tons melt per SCR [€/t] 3R [€/t] (recuperative) measures** Lownox
silica crown* fused cast
day) [€/t] [€/t] measures*** [€/t]
[€/t] crown* [€/t]
Float 500 3.3 6-6.25 0.85-1.1 6.83 (0.06) 11.35 (0.06)
Float 700 2.6-2.9 5.25-5.6 2.33
Float 900 2.6 0.58 1.82
Container 150 3.07 (0.06) 5.28 (0.06)
Container 200-225 2.56 4.5 2.28 0.76 1.63 3.27 (0.06) 5.39 (0.06)
Container 300 2.13 4 1.88 0.59 1.34
Container 450 1.84 0.47 1.09 5.18 (0.06) 7.16 (0.06)
Container
450 3.73 1.02 1.5 estimated
cross-fired
Tableware
30-35 8 (at 0.10) –4.32
(recuperative)
Tableware
70 (at 0.10) +12.76
(regenerative)
Tableware
100 4.9
(regenerative)
Tableware
150 8 (high E-boost)
(regenerative)
Tableware
190 0.7
(regenerative)
Special glass
250 3.34
oxygen fired
Special glass
regenerative 700 2.8
fired
E-glass 100 4.1 6.20 (0.08)
* Oxygen cost in Euros per Nm³ given between brackets
** Basic Lownox measures: adjustable burners, oxygen sensors, air-fuel control
*** Extended Lownox measures: basic measures plus modifications burner ports & combustion chamber


Mis en forme : Police :10 pt
Document on Best Available Techniques in the Glass Manufacturing Industry.”
Available Techniques (BAT) and limit values. Submitted to the Task Force on Heavy Metals of
UNECE CLTRAP
related to the abatement of the transboundary Transport of nitrogen oxides from stationary
sources, DFIU, 1999.
[4] UNECE 2003. Background document on the sector of glass industry. Geneva (available on the
EGTEI website: http://www.citepa.org/forums/egtei/egtei_index.htm)
[5] DEFRA 2006: Sector Guidance Note IPPC SG2 - Secretary of State's Guidance for A2 Activities
in the Glassmaking Sector. http://www.defra.gov.uk
[6] UNECE 1999. Draft guidance documents on control techniques and economic instruments to
the protocol to abate acidification, eutrophication and ground level ozone.
[7] Bingham and Marshall: Reformulation of container glasses for environmental benefit through
lower melting temperatures. Glass Technology, 2005, 46 (1), pp 11-19.
[8] VDI 2578. Verein Deutscher Ingenieure: Emission control Glassworks, VDI/DIN Handbuch
Reinhaltung der Luft, Band 3, 1999
Safety Guidelines for Glass Manufacturing
[10] CPIV Expert communication 05.05.2009
[11] Beerkens 2007 Evaluation of costs associated with air pollution control for glass melting
furnaces – A study to support the revision of the IPPC reference document on best available
techniques in the glass manufacturing industry 2008, Ordered by CPIV, Brussels, Belgium.
General References:
US Environmental Protection Agency (US EPA). 1995. “AP-42 Section 11.15, Glass Manufacturing.”
Washington, DC.
US Environmental Protection Agency (US EPA). Standards of Performance for New Stationary
Sources. Subpart CC – Standards of Performance for Glass Manufacturing Plants, 40 CFR Part 60.
Washington, DC.
US EPA 1995 Glass Manufacturing Point Source Category. Subpart E – Float Glass Manufacturing
Subcategory40 CFR Part 426. Washington, DC.


7.13 Man-made fibres production

7.13.1 Coverage
The sector production of man-made mineral fibres includes installations for the manufacture of
continuous filament glass fibre, of mineral wool and of high temperature insulation glass wools with a
melting capacity exceeding 20 tonnes per day. Mineral wool refers to glass wool and stone wool
insulating materials, i.e., randomly interlaced masses of fibre that are bound by a resin based binder
[1], [2].

Several production steps and environmental issues of the sector “production of man -made fibres” are
the same as for the sector “glass production”, so the following represents additional information to the
basic production technologies, BAT etc. of the “glass production” sector.
Continuous Filament Glass Fibre is produced using recuperative or oxy-fuel fired furnaces. The
glass flows from the furnace to the forehearths where is passes through bushings on the base. The
glass is drawn through the brushing tips to form continuous filaments. The filaments are drawn
together and pass over a roller or belt, which applies an aqueous coating to each filament. The coated
filaments are gathered together into bundles (strands) for further processing.
Glass wool furnaces are usually electric melters, gas fired recuperative furnaces, or oxy-fuel
furnaces. Glass flows along a forehearth and through single orifice bushings into rotary centrifugal
spinners. Fiberising is by centrifugal action with attenuation by hot flame gases. An aqueous phenolic
resin solution is sprayed onto the fibres. The resin-coated fibre is drawn under suction onto a moving
conveyor and then passes through an oven to dry and cure the product.
Stone wool is usually produced with a coke fired hot blast cupola. The molten material gathers in the
bottom of the furnace and flows out along the spinning machine. Air is used to attenuate the fibres and
to direct them onto the collection belts. An aqueous phenolic resin solution is prayed onto the fibres by
a series of spray nozzles. The remainder of the process is essentially as for glass wool.
Ceramic fibre is produced using electric furnaces. The melt is fiberised either by high -speed wheels
or high pressure air jet, and the fibres are drawn onto a collection belt. The product can either be
baled at this point or processed into blanket to be baled as product or needle felted.
Mineral wool
In the mineral wool sector, mainly recuperative and electrical furnaces are used, besid e also oxy-gas-
fired furnaces for glass wool production.
As in the glass industry, the main environmental issues are emissions to air (fossil fuelled furnaces
and high-temperature oxidation of atmospheric nitrogen lead to emissions of SO 2, NOX, CO2 and Dust)
and energy consumption.
In addition to the emissions found in the glass manufacturing sector, two further important emission
sources exist: the forming area (application of binder to the fibres) and the curing oven (drying and
curing of binder). In the forming area, dust, phenol, formaldehyde and ammonia are emitted, in the
curing oven volatile binder components, breakdown products and combustion products are emitted.
For the production of high temperature insulation glass wools, only electrically hea ted furnaces are
used. Thus only dust emissions are relevant and to a minor extent some organic compounds [1], [2].


7.13.3.1 SO2
In stone wool production, important sources of SO2 emissions (in addition to coke) are the use of
blast furnace slag and cement bond briquettes in the batch. The availability of low sulphur coke and
slag are restricted by the limited supply within economical transport distances. Slag can normally be
eliminated from most batches (except for examples white fibre for specific applications). Using cement
bond waste briquettes involves a balance between waste minimisation and SO 2 emission reduction
[2].
For continuous filament glass fibres, BAT is considered to be the use of secondary abatement for
dust with dry or semi-dry acid gas scrubbing where appropriate. The upper parts of the range
correspond to dust recycling (otherwise lower values are expected) [2].
For glass wool production, SO2 emissions are often low without any specific abatement equipment,
as almost all furnaces are electrically or gas heated and very low levels of sulphate are used. If oil -
fired furnaces are used, acid gas scrubbing will usually be necessary to protect dust abatement
equipment [2].
For stone wool production, the given BAT values correspond to a situation, where priority is given to
the recycling of process wastes. Where these values are not reached, acid gas scrubbing may
represent BAT (dry scrubbing likely to be most cost effective) [2].
Table 1: SO2 emission levels associated with BAT for furnaces in fibres production [2]
1
3
Emission source mg/Nm (kg/tonne) Comments
gas-firing oil-firing
If sulphates in batch, gas-firing values
3
Continuous filament glass could be up to 800 mg/Nm (3.6
500 – 1000 kg/tonne).
fibre < 200; (0.9)
(2.25-4.5) For oil-firing, upper end of range
relates to dust recycling.
generally < 50 300 – 1000
Glass wool Generally low sulphate glass.
(0.1) (0.6-2.0)
(a) Stone charge
Stone wool (coke fired) < 600 (1.5)
(b) 45 % cement bound briquettes
with waste minimisation < 1100 (2.7)
(c) Cement briquettes inc. filter dust
and recycling as priority. < 1400 (3.4)
(a) Stone charge

Stone wool (coke fired) < 200 (0.5)
(b) 45 % cement bound briquettes
with SO2 reduction as < 350 (0.8)
(c) Cement briquettes inc. filter dust
priority. < 400 (1.0)
Ceramic fibre (electric Electric furnaces only, concentration

< 0.5 kg/tonne melt
melting) will be case specific.
1
systems, short-term peak values, which could be higher, have to be regarded.^

7.13.3.2 NOx
For continuous filament glass fibres, BAT is considered likely to be oxy-fuel melting, however this is
no firm conclusion. SCR is considered unlikely to be applicable in the near future due to fears of
borate condensation in the catalyst. When using oxycombustion, special care has to be taken with
regard to energy efficiency so as not to reduce the NO X emission abatement potential.
For glass wool production, BAT for NOX is considered to be oxy-firing or predominantly electrical
melting, conventional firing combined with primary or secondary measures may also be judged BAT if
emissions within the ranges are achieved.
Stone wool cupolas do not generally give rise to substantial NO X emissions, however where tank
furnaces are used, the NOX BAT levels correspond to the one of glass wool production [2].
Table 2: NOX emission levels associated with BAT for furnaces in fibres production [2]
BAT associated
1
Emission source emission levels Comments
3
mg/Nm or (kg/tonne)
Continuous filament glass (0.5-1.5)
fibre, oxycombustion
Sector in a transition period concerning NO X
Continuous filament glass control, emissions generally higher than
fibre, other than 500-700 1000 mg/Nm³ (4.5 kg/tonne), with
oxycombustion conventional combustion 800 mg/Nm³ (3.6
kg/tonne) possible
500-700
Glass wool
(0.5-1.4)
Stone wool (0.5) For tank furnaces: see level for glass wool
Ceramic fibre (<0.1-0.5)
1

Many statements from the section on glass manufacturing (chapter 7.12) can be transferred to the
production of man-made fibres, for example that oxy-fuel burners can reduce waste gas volume and
flue dust production by 60%. End-of-pipe prevention and control techniques to reduce dust emission
commonly include the installation of electrostatic precipitators (ESP) reducing the emissions to 30
3 3
mg/m and fabric (baghouse) filters reducing the emissions below 10 mg/m [1].
For continuous filament glass fibres, BAT for dust is the use of an electrostatic precipitator or bag
filter operating, where appropriate, in conjunction with a dry or semi-dry acid gas scrubbing system.
For this sector, cooling the waste gas and the positioning of the abatement system are very important
for optimising efficiency. If existing equipment can achieve emission levels of 50 mg/Nm³, costs of
replacement prior to the next rebuild could be disproportionate to the advantages gained [2].
For mineral wool (glass and stone wool) production, the use of an electrostatic precipitator or bag
filter is considered BAT, while acid gas scrubbing systems are not considered necessary due to
prevalence of electric or gas heating). For downstream processes, the use of either a wet electrostatic
scrubber, a packed bed scrubber, or a stone wool filter (stone wool processes only) is considered
BAT.

In the glass wool production, the cooling of the waste gas and the positioning of the abatement
system are very important for optimising the efficiency. If existing equipment can achieve emission
levels of 50 mg/Nm³, costs of replacement prior to the next rebuild could be disproportionate to the
advantages gained.
For ceramic fibre production, electric melting with a bag filter system is considered BAT [1].
The production of man made fibers is not identified as a major source ob black carbon, according to
references [4], [5] and [6]. However BC emission data are scarce. If BC is present in dust, BAT
measures described just above efficient for fine particles, are also efficient for BC.
Table 3: dust emission levels associated with BAT for furnaces in fibres production [2]
BAT associated emission

1
Emission source levels Comments
3
mg/Nm or (kg/tonne)
Electrostatic precipitator or bag filter (plus
dry or semi-dry acid gas scrubber where
Continuous filament appropriate)
5-30; (<0.14)
glass fibre If existing equipment achieves 50 mg/Nm³,
costs of major modifications prior to rebuild
may be disproportionate
Glass wool Electrostatic precipitator or bag filter.
5-30 (<0.1) If existing equipment achieves 50 mg/Nm³,
Stone wool costs of major modifications prior to rebuild
may be disproportionate
Downstream operations 20-50 combined forming and curing
of mineral wool plants 5-30 curing ovens for stone wool
Ceramic fibres <10
1
7.13.3.4 VOC
In the production of man-made mineral fibres, VOC emissions can be reduced by switching to low
organic solvent containing binding agents and/or by VOC adsorption and incineration.
For stone wool processes, BAT is considered the use of a thermal incineration unit to reduce curing
oven emissions.
Mis en forme : Normal, Interligne :
simple
Table 4

Table 4 shows emission levels achievable by switching from conventional to reformulated binding
agents and by destructing the emissions generated in the forming and the curing steps (catalytic
incineration or adsorption preceded by precipitation of dust) [1].
Table 4: VOC emission levels associated with BAT for fibres production [2]
1
Emission Source levels Comments
3
mg/Nm or (kg/tonne)
10-50 [Erreur ! Signet non
défini.] forming area and combined forming and
Glass wool
curing emissions
(0.12) [1]
curing ovens: Thermal incineration unit
Stone wool < 10
considered BAT
Ceramic fibre 10-20
1


An emerging technology is the Plasma Melter, which makes use of the electrical conductivity of molten
glass and operates with negligible dust emissions. It is however not expected to be a viable technique
for melting within the foreseeable future.
7.13.5 Cost data for emission reduction technologies

For general cost data for abatement techniques see section 7-12 (glass production).
Table 5: cost data for abatement techniques (only fibres production) [1]
Abatement Typical NOX Dust VOC Investment Investment Operating

Technique Flow Rate 3 3
mg/Nm or mg/Nm or mg/Nm or
3 for new for existing Cost M€/y
Nm³/h (kg/tonne) (kg/tonne) (kg/tonne) process M€ process M€
Impact
150000-
scrubber + 50 (1.8) 30 (1.8) 1.3+30 % 1.6+40 % 0.1+0.02
300000
cyclone
Impact
scrubber + 150000-
20 (1.2) 30 (1.8) 3.8+30 % 4.6+40 % 0.12+0.02
cyclone 300000
+WEP
Impact 150000-
50 (1.8) 25 (1.8) 3.5+30 % 4.2+40 % 0.21+0.02
scrubber + 300000

cyclone
+PBS
Stone wool 150000-
20 (0.7) 25 (1.0) 1.3+30 % 1.5+30 % 0.2+0.1
slab filter 250000
150000-
Incinerator 200 (0.6) 20 (0.1) 10 (0.04) 1.3+40 % 1.6+30 % 0.2+0.1
300000
150000-
Stack 0.7+40 % 0.8+40 %
300000

Available Techniques (BAT) and limit values. Submitted to the Task Force on Heavy Metals of
UNECE CLTRAP
Document on Best Available Techniques in the Glass Manufacturing Industry.”
[3] UNECE. 2003. Background document on the sector of glass industry. Geneva (available on the
EGTEI website: http://www.citepa.org/forums/egtei/egtei_index.htm)
General References:
US Environmental Protection Agency (US EPA). 1995. “AP-42 Section 11.15, Glass Manufacturing.”
Washington, DC.
Washington, DC.
US EPA. 1995 .Glass Manufacturing Point Source Category. Subpart E – Float Glass Manufacturing
Technical background documents for the actualisation and assessment of UN/ECE protocols related
to the abatement of the transboundary Transport of nitrogen oxides from stationary sources, DFIU,
1999.

7.14 Ceramics
7.14.1 Coverage
The sector addresses industrial installations for the manufacture of ceramic products by firing, in
particular roofing tiles, bricks, refractory bricks, tiles, stoneware or porcelain, with a production
capacity exceeding 75 tonnes per day and/or with a kiln capacity exceeding 4 m³ and with a setting
density per kiln exceeding 300 kg/m³ [1].

The manufacture of ceramic products takes place in different types of kilns, with a wide range of raw
materials. The general process of manufacturing ceramic products, however, is rather uniform except
that for some products a multistage firing process is used [1].
The main process steps are:
raw material preparation and component mixing
forming and shaping of ware, decoration
drying ware
firing ware
product finishing
addition of auxiliary materials [2]
In general, raw materials are mixed and cast, pressed or extruded into shape. The water used for a
thorough mixing and shaping is evaporated in dryers and the products are placed either by hand in the
kiln (especially for periodically operated shuttle kilns) or placed onto carriages that are transferred
through continuously operated tunnel or roller hearth kilns. For the manufacture of expanded clay
aggregates, rotary kilns are used. During firing, a very accurate temperature gradient is necessary to
ensure that the products obtain the right treatment. Today natural gas, liquefied pe troleum gas and
light fuel oil are mainly used for firing, while heavy fuel oil, liquefied natural gas, biogas/biomass
electricity and solid fuels can also play a role as energy source for burners. The main environmental
issues are emissions to air as dust and gaseous emissions (carbon oxides, nitrogen oxides, sulphur
oxides and others) [1], [3].

For all following pollutants, reductions can be achieved by reducing the energy consumption. In order
to achieve this, it is BAT to apply a combination of the following techniques:
improved design of kilns and dryers
recovery of excess heat from kilns, especially from their cooling zone
applying a fuel switch in the kiln firing process (substitution of heavy fuel oil and solid fuels)
modification of ceramic bodies
It is furthermore considered BAT to reduce primary energy consumption by applying cogeneration on
the basis of useful heat demand, within energy regulatory schemes, which are economically viable [1].
7.14.3.1 SO2
The emissions of SO2 in ceramic kiln exhaust gas depend on the sulphur content of the fuel and
certain raw materials (gypsum, pyrite, etc). The presence of carbonates in raw material s however may
reduce sulphur emissions. In general, techniques for reducing SO 2 emissions include the use of low
sulphur content fuels (such as natural gas or LPG), of low-sulphur raw materials and low sulphur
5 July 201224 September 2012 Page 159

body-additives. Further reductions are possible by optimising the heating process and lowering the
firing temperature and the use of dry or wet scrubbers [4].
Table 1: SO2 emission levels associated with BAT for ceramics production [1]
BAT associated
1
Emission Source emission levels Comments
3
mg/Nm
< 500 Sulphur content in raw material <0.25%
500-2000 Sulphur content in raw material >0.25%; the

Flue gas from kiln firing higher level only applies to raw material with
an extremely high sulphur content
[Comment: IFC guideline gives a general
value of 400 for kiln operations at 10% O 2]
1
Reference conditions: Oxygen content 18 %
3
IFC guideline [4] gives a general value of 400 mg/Nm for kiln operations in ceramic tile production at
3
10% O2 or 110 mg/Nm at 18% O2.
7.14.3.2 NOx
The techniques for reducing emissions of gaseous compounds in ceramics manufacturing can be
summarized as reducing the input of pollutant precursors (raw materials and additives) and heating
curve optimisation (optimal peak flame temperatures, computerized control of kiln firing).
For expanded clay aggregates, it is BAT to keep the emissions from rotary kiln firing below the given
BAT value by applying a combination of primary measures/techniques [1], [4].
Table 2: NOX emission levels associated with BAT for flue gas from kiln firing in ceramics
production [1]
BAT associated
1
3
mg/Nm
< 250 Daily average value stated as NO2 for kiln
gas temperatures below 1300 °C
Daily average value stated as NO2 for kiln
Flue gas from kiln firing < 500
gas temperatures of 1300 °C or above
[Comment: IFC guideline gives a general
value of 600 for kiln operations at 10% O 2]
Flue gas from kiln firing
< 500 Daily average value
(expanded clay aggregates)
1
3
IFC guideline [4] gives a general value of 600 mg/Nm for kiln operations in ceramic tile production at
3
10% O2 or 164 mg/Nm at 18% O2.

General BAT
The processing of clay and other ceramic raw materials inevitably leads to dust formation, especially
drying, grinding, milling, screening mixing and conveying can all result in the emission of fine dust ; the

fuels also contribute to these emissions. While diffuse dust emissions should be minimized by
appropriate measures (use of silos for all bulk storage of dusty materials or use of confined storage
areas within buildings or use of enclosed containers/packaging), for channelled dust emissions, it is
BAT to use fabric filters.
For drying processes, it is BAT to clean the dryer, to avoid the accumulation of dust residues in the
dryer and to adopt adequate maintenance protocols.
For kiln firing, it is considered BAT to use low ash fuels, to minimise dust formation caused by the
charging of the ware to be fired in the kiln and to use flue-gas cleaning by filters or packed bed
absorbers [1], [2].
The production of ceramics is not identified as a major source of black carbon, according to references
[6] and [7]. However BC emission data are scarce. As presented in chapter 6.1, BC emissions occur
during incomplete combustion phases and during start-up periods. If BC is present in dust, BAT
measures described just above, efficient fine particles, are also efficient for BC.
Sector specific BAT

For wall and floor tiles, household ceramics, sanitaryware, and technical ceramics, vitrified clay pipes
it is considered BAT to reduce channelled dust emissions from spray glazing processes by applying
fabric filters or sintered lamellar filters.
For wall and floor tiles, household ceramics, technical ceramics it is BAT to reduce channelled
emissions from spray drying processes by applying fabric filters, or alternatively cyclones in
combination with wet dust separators for existing installations, if the rinsing water can be reused.
For expanded clay aggregates, it is considered BAT to reduce channelled emissions from hot off-
gases by applying electrostatic precipitators or wet dust separators.
For wall and floor tiles, it is BAT to reduce dust emissions from flue-gases of kiln firing processes, by
applying flue-gas cleaning with a fabric filter [1].
Table 3: dust emission levels associated with BAT for ceramics production [1]
BAT associated
1
3
mg/Nm
General BAT
Channelled emissions from
1-10 Half hourly average value by applying fabric
operations other than drying,
filter; may be higher on specific conditions
spray drying or firing
Drying processes 1-20 Daily average
Daily average; flue gas cleaning with filter
1-20
Kiln firing Daily average; flue gas cleaning with
< 50
cascade-type-packed bed absorbers
Sector specific BAT
Spray glazing
(For wall and floor tiles,
household ceramics, 1-10
sanitaryware, technical
ceramics, vitrified clay pipes)
Spray drying
1-30 Half hourly average; fabric filters
(For wall and floor tiles,
household ceramics, 1-50 Cyclones in combination with wet dust
technical ceramics) separators for existing installations, if the
rinsing water can be reused
Expanded clay aggregates 5-50 Daily average
Kiln firing
1-5 Daily average
(for wall and floor tiles)

1
7.14.3.4 VOC
Emissions of volatile organic compounds (VOC) result from incomplete combustion and from the
organic material in the raw materials (e.g., binders, plasticizers, lubricants).
For bricks and roof tiles, refractory products, technical ceramics, inorganic bonded abrasives it is
considered BAT to reduce the emissions of VOCs from the flue-gases of firing processes – with raw
gas concentrations of more than 100 to 150 mg/m³, depending on the raw gas characteristics, e.g.,
composition, temperature – to the given BAT value by applying thermal afterburning either in a one or
a three chamber thermo-reactor.
For refractory products treated with organic compounds it is BAT to reduce the emissions in low off -
gas volumes from the treatment with organic compounds by applying activated carbon filters. For h igh
off-gas volumes it is BAT to reduce the emissions of VOCs from the treatment with organic
compounds by applying thermal afterburning [1], [5].
Table 4: VOC emission levels associated with BAT for ceramics production [1]
BAT associated
1
3
mg/Nm
Flue gases of firing
For raw gas concentrations of more than
processes for bricks and roof
5-20 100-150 mg/m³; as daily average (total C);
tiles, refractory products,
by application of afterburning, in a 1 or 3
technical ceramics, inorganic
chamber thermo-reactor
bonded abrasives
Refractory products 5-20 Thermal afterburning
1


The use of radiant tube burners (flame place inside a heat resistant tube, still under development) can
reduce HF and SO2 emissions. Microwave assisted firing and microwave dryers aim at shorter firing
cycles and less excess heat. Large refractory products can be dried more efficiently by placing steel
foils or carbon fibres as the heating element into the refractory mix [1].


Table 5: cost data for different emission reduction techniques for ceramics production [1]
Common sizes/ Rough

Absorbent Sorbent cost Operation
Cleaning flowrates for the investment Maintenance
Field of Application /adsorbent (EUR/tonne) cost
system/type ceramic industry guideline (EUR/y)
(EUR/y) (EUR/t)
(Am3/h)
1 (EUR)
Dust abatement
Complete areas in the
6000 – 150000
Fabric filter/bag plant, preparation,
house conveying, storage, 900 to 70000 (Depending on 0.03 – 0.1
size and amount
forming area, handing
of ductwork)
over locations, etc.
Complete areas in the
plant, preparation, 25000 – 65000
Central vacuum conveying, storage, (Depending on
forming area, 900 to 1000
cleaner amount of
handing over locations, ductwork/pipes)
Kiln cars etc.
Kiln car cleaning
system
(In different 40000 –200000
execution: Fixed Kiln cars 8000 to 30000 (Depending on
nozzle, moving size and
nozzle, lifting and execution)
adjusting of the
plateau)
Dust abatement for hot
Electrostatic 1000000 –
and large offgas Up to 100000 0.1 – 0.2
precipitator 3000000
streams
Inorganic gaseous compounds abatement

Ca(OH)2
Module system Mainly HF reduction Very low flowrates 45000 – 100000 ~500 ~46000 EUR/yr
Honeycomb
30 – 55
2500 to 140000
EUR/tonne
Cascade type (no lower or upper 23400 – 4800
Mainly HF reduction CaCO3 40000 – 500000 ~2000 (delivered)
packed bed absorber limit)
4000 – 30000
EUR/yr
95 – 110
2500 to 140000 EUR/tonne
Cascade type Mainly HF, HCl and SO2 Modified/fabricat 40000 – 500000
(no lower or upper ~2000 (delivered)
packed bed absorber reduction ed absorbent
limit) up to 60000
EUR/yr
30 – 55
EUR/tonne
Countercurrent type CaCO3
2500 to 140000 (delivered)
packed bed Mainly HF, HCl, and and modified/ 80000 – 800000
(no lower or upper ~2500 respectively 95
absorber/ series SO2 reduction fabricated
modules limit) – 110
absorbent
EUR/tonne
(delivered)
95 – 110
Dry sorption with Ca(OH)2 2500 to 140000 EUR/tonne
Mainly HF, HCl, SO2 ~4000 107500 –
fabric filter (fly in different (no lower or upper 80000-1000000 (delivered)
Particulate reduction 130700
stream system) qualities limit) 8000 – 45000
EUR/yr
Dry sorption with Ca(OH)2 95 – 110

fabric filter (fly Mainly HF, HCl, and 2500 to 140000 EUR/tonne 107500 –
in different 200000 –
stream system) with SO2 Particulate qualities (with (no lower or upper ~6500 (delivered) 130700
1600000
conditioning of the reduction little water limit) 8000 – 45000
reaction product added) EUR/yr

95 – 110
2500 to 140000 EUR/tonne
Mainly HCl and SO2 400000 –
Wet scrubber Alkali water (no lower or upper up to 8000 (delivered)
reduction 2000000
limit) 8000 – 45000
EUR/yr +water
VOC abatement
Thermal afterburning
180000 –
in a thermoreactor VOC reduction 10000 – 50000 500 – 4500
420000
(external)
Internal
carbonization gas VOC reduction 42000 – 300000 500 – 8000
combustion
Note: In the column ‘common sizes/flowrates’ and in the column ‘rough investment guideline’ there are ranges. It is reasonable to assume that the small Am3/h-figures correspond to the low
investment figure in EUR and that the high Am3/h figure corresponds to the high investment figure in EUR. In between the increase is not linear, normally the more Am 3/h are treated, and the lower
the investment per Am3 is.
1
) The flowrates are given in ‘actual m3’ (Am3, as opposed to normal m3, standard condition) because actual flue-gas has to be treated.

Mis en forme

Document on Best Available Techniques in the Ceramics Manufacturing Industry.”
[2] DEFRA 2007: Sector Guidance Note IPPC SG7 - Secretary of State's Guidance for the A2
Ceramics Sector including Heavy Clay, Refractories, Calcining Clay and Whiteware.
http://www.defra.gov.uk
[3] Rentz, O., A. Schmittinger, R. Jochum and F. Schultmann (2002): Exemplarische Untersuchung
der praktischen Umsetzung des integrierten Umweltschutzes in der Keramischen Industrie unter
Beachtung der IVU-Richtlinie und der Erstellung von BVT-Merkblättern, DFIU-IFARE Karlsruhe,
report on behalf of Umweltbundesamt, Germany, 221 pp.
Safety Guidelines for Ceramic Tile and Sanitary Ware Manufacturing
[5] US Environmental Protection Agency (US EPA). 1995. “AP-42 Section 11.15, Glass
Manufacturing.” Washington, DC.
[7] UNECE - Ad Hoc Expert Group on Black Carbon - Black carbon - Report by the Co-Chairs of the
Ad Hoc Expert Group on Black Carbon. Executive Body for the Convention on Long-range
General References
Washington, DC.
US EPA 1995 .Glass Manufacturing Point Source Category. Subpart E – Float Glass Manufacturing
Beerkens 2007 Evaluation of costs associated with air pollution control for glass melting furnaces – A
study to support the revision of the IPPC reference document on best available techniques in the glass
manufacturing industry 2008, Ordered by CPIV, Brussels, Belgium.
European Commission. 2007: Proposal for a Directive of the European Parliament and of the Council
on Industrial Emissions (Integrated Pollution Prevention and Control) (Recast)

7.15 Pulp production1

7.15.1 Coverage
This chapter covers sulphate (Kraft) and sulphite pulping processes which are the most commonly
used processes. Pulp production [5] processes are sources of nitrogen oxides (NOx), sulphur dioxide
(SO2) and dust (TSPincluding PM10, PM2.5 and black carbon). Mis en forme : Indice
Mis en forme : Indice
For chemical pulping process as Kraft process and sulphite process, wood is needed. Wood is first
debarked and then reduced into chips which are screened. The removed material from the screening
operation can be used in the process as solid fuel or be sold for other purposes.
The screened material is then cooked in a cooking plant with different chemical depending on the
process. The cooking stage can be continuous or batch.
The sulphate or Kraft process is the most used pulping process, due to the quality of the produced
pulp and to its applicability to all wood species.
During the cooking stage of the Kraft process, fibres are liberated from the screened chips using a
solution of white liquor to dissolve the lignin. White liquor is composed of sodium hydroxide and
sodium sulphide.
The pulp formed in the cooking plant contains fibres and spent cooking liquor; black liquor. Black
liquor is removed from the pulp during washing steps and is led to the recovery process. During this
recovery process, chemicals and energy are recovered. The recovery system normally enables the
whole production process to be self-sufficient in heat and energy.
After the cooking step, delignification can be continued by an oxygen delignification. Then the pulp is
purified.
The next step of the process is the bleaching, it is only necessary to obtain brighter Kraft pulp. The
bleaching is generally composed of a sequence of separate bleaching stages (4-5). During those
stages, chlorine dioxide, oxygen, ozone and peroxide can be used as bleaching agent.
After the bleaching, pulp is purified.
Depending on the type of plant; pulp mill or integrated pulp and pap er mill, the final pulp is dried to be
transported or directly used as it is [1], [5].
After the cooking step, black liquor is removed and led to a recovery process. To be used as
performing fuel, recovered black liquor needs to be concentrated. It is concentrated by evaporation to
65-75% dry-solids content. During the evaporation, non condensable gases and condensates are
recovered. Non condensable gases are burnt with malodorous gases while condensates are purified
and used as chemicals during the washing of the pulp.
The concentrated black liquor is burnt in a recovery boiler to recover the sodium and sulphur content
in a suitable chemical form to regenerate the pulping chemicals and recover energy from the flue
gases [1], [5].
The recovery system also enables the regeneration of chemicals; the smelt from recovery boiler are
recovered and dissolved in water or white liquor. The solution is then clarified and caus ticized with
lime to form sodium hydroxide, which is then used to produce white liquor.
The calcium carbonate recovered from the causticizing is used in a lime kiln to regenerate lime.
Mis en forme : Anglais (États Unis)

1 Mis en forme : Anglais (États Unis)
The information included in this subchapter is based on the BREF on pulp and paper industry [1], which is
currently under revision at the Institute for Prospective Technological Studies in Sevile (IPTS). Mis en forme : Anglais (États Unis)

Air emissions from this process come mainly from recovery boiler, lime kiln, auxiliary boilers and pulp
drying.
The recovery boiler is the main source of emissions in the Kraft process. The boiler is fed with
concentrated black liquor. NOx, SO2, and dust emissions occur, and the rate of these emissions are Mis en forme : Indice
influenced by the combustion efficiency and the sulphur content of the black liquor.The recovery
boiler is however the main source of emissions in the Kraft process. The boiler is fed wi th
concentrated black liquor, which is the cause of NO x, SO2 and dust emissions. These emissions are
influenced by the efficiency of the combustion and the sulphur content of the black liquor.
The lime kiln is also responsible of similar emissions as in lime production (refer to chapter 7.11.2).
A bark boiler and other boilers are used in the Kraft process as auxiliary boilers to cover the energy
demand of the pulp production. These boilers can be fed with solid, liquid or gaseous fuel [1].
The sulphite process is less used than the Kraft process, due to the lower quality of the produced
pulp and to its non applicability to certain wood species. Environmental issues are in most cases more
expensive to solve than in the Kraft process.
In the sulphite process, the same processes are used, only the chemicals used are different. Hence,
recovering and regenerating steps are slightly different.
The white liquor used in the cooking plant is composed of magnesium sulphite and magnesium
bisulphite. The cooking step is most of the time a batch process.
As in the Kraft process, chemicals and energy are recovered to enable the whole production process
to be self-sufficient in heat and energy.
Air emissions from this process come from the same sources as in the Kraft process and recovery
boiler is also the main source of emissions [1].

If not stated otherwise the data refer to yearly average values, standard conditions and the reference
oxygen content is:
6% with solid fuel or biofuel;
3% with liquid fuel or gaseous fuel
SO2:
Kraft process
The recovery boiler is the major source of SO 2 emissions. Therefore BAT to reduce SO2 emission
levels in pulp industry is first of all reducing emissions from this boiler.
Malodorous gases from cooking plant, delignification step or evaporation of the black liquor need to be
collected and incinerated in the lime kiln, the recovery boiler or the auxiliary boilers. Emissions from
incineration need to be controlled.
In the recovery boiler, the use of high dry solids content of black liquor is a primary measure to reduce
SO2 emissions. A high dry solid content >75% permits to reduce significantly emissions.
In order to reduce SO2 emissions from the recovery boiler, a flue gas wet scrubber can be installed as
secondary measures. The scrubbing enables the removal of SO 2 and dust. The pH is controlled and
regulated by addition of liquor or sodium hydroxide. SO 2 reacts with the scrubbing liquor to form
sodium sulphite (Na 2SO3) or sodium sulphate (Na 2SO4). The usual removal efficiency of this scrubbing
3 3
is > 90 %. From initial concentration levels of 50-200 mg/Mm , levels of 10-50 mg/m can be Mis en forme : Exposant
3 3
reachedFor initial concentration levels of 50 – 200 mg/Nm , levels of 10 - 50 mg/m can be reached. Mis en forme : Exposant

The reduction of SO2 emissions from other boilers involves the use of low sulphur content fuels or the
use of scrubber to control emissions [1].
The following table gives an overview of BAT associated SO2 emission levels for Kraft pulping process
using different techniques.
Table 1: associated SO2 emission levels with BAT to reduce emissions in Kraft pulping process
[1]
Associated
emission level
with BAT
3
(mg S/Nm )
Recovery boiler SO2 scrubbing system 10 – 50
(5% O2) If with High dry solids content of black liquor (>75%) it goes to 5 – 10
1
Auxiliary boilers Use of fuel with low sulphur content 100 – 200
2
25 – 50
3
<5
4
<15
SO2 scrubbing system 1

50 – 100
1
feed with coal or heavy fuel oil
2
feed with gas oil
3
feed with gas
4
feed with biofuel
Sulphite process
As for Kraft pulping process, the recovery boiler is responsible for the major part of SO2 emissions in
the sulphite pulping process.
Similar primary measures can be applied to reduce emissions.
In order to reduce SO2 emissions from the recovery boiler, a flue gas multi staged scrubber can be
used. SO2 emissions from the other boilers can be reduced using the same reduction techniques as
for Kraft process.
The following table gives an overview of BAT associated SO2 emission levels for sulphite pulping
process using different techniques.
Table 2: associated SO2 emission levels with BAT to reduce emissions in sulphite pulping
process [1]
Associated
emission level with
BAT
3
(mgS/Nm )
Recovery boiler SO2 multi-staged scrubber 50 – 150
(5% O2)
1
Auxiliary boilers Use of fuel with low sulphur content 100 – 200
2
25 – 50
3
<5
4
<15
SO2 scrubbing system 1

50 – 100
1
2
feed with gas oil

3
feed with gas
4
feed with biofuel
Mis en forme : Légende, Gauche

NOx:
Kraft process
The main sources of NOx emissions in the Kraft process are the lime kiln and the recovery boiler. The
recovery boiler is responsible for the largest part of NOx emission due to the amount of black liquor
burnt. Low NOx burners and modified combustion conditions with staged air feed system can reduce
the emission levels.
The high combustion temperature in the lime kiln is also responsible of NO x emissions. The level of
emissions is influenced by the type of fuel used. Primary measures such as adjusting functioning
parameters like flame shape or air distribution, can control the NOx emissions.
Auxiliary boilers within the pulp industry are of a very large range size (from 10 to above 200 MW).
Therefore, different measures can be applied from small boiler to large boilers. In smaller boilers,
structural and primary measures are cost effective while in larger boilers, secondary measures can
also be applied [1].
The following table gives an overview of BAT associated NOx emission levels for Kraft pulping
process.

Table 3: associated NOx emission levels with BAT to reduce emissions in Kraft pulping
process [1]
Associated
emission level
with BAT
3
(mg/Nm )
Recovery boiler (5% O2) Low NOx burner, staged air feed system 80 – 120
Lime kiln adjusting parameters :

5
oil firing 80 – 180
5
gas firing 300 – 540
1
80 – 110
2
45 - 60
structural and primary measures 3
Auxiliary boilers 30 - 60
4
60 – 100
1
50 - 80
SNCR 4
40 – 70
1
2
feed with gas oil
3
feed with gas
4
feed with biofuel
[5 AEL exactly reproduced from the BREF [1]. However 300-540 should refer to oil firing and 80-180 to gas firing Mis en forme : Retrait : Gauche : 0
cm
As written in the Bref document, it could be an error] Mis en forme : Police :(Par défaut)
Arial, 8 pt, Anglais (États Unis), Non
Surlignage
Sulphite process
The main sources of NOx emissions in the sulphite process are the boilers. Hence, NO x emissions
from those boilers can also be reduced using the same reduction techniques as for Kraft process.
The following table gives an overview of BAT associated NOx emission levels for sulphite pulping
process in pulp industry.
Table 4: associated NOx emission levels with BAT to reduce emissions in sulphite pulping
process [1]
Associated
emission level
with BAT
3
(mg/Nm )
Recovery boiler
Low NOx burner, staged air feed system 200 - 300
(5% O2)
1
80 - 110
2
45 - 60
Structural and primary measures 3
Auxiliary boiler 30 - 60
4
60 - 100
1
50 - 80
SNCR 4
40 - 70
1
2
feed with gas oil
3
feed with gas
4
feed with biofuel

Kraft process
In kraft pulp mills, dust emissions come from different sources, mainly the lime kiln, the auxiliary boiler
and the recovery boiler. Emissions can be controlled by electrostatic precipitator and/or SO 2 scrubbers
depending on the emission source process. Bag filters can also be used [7].
The SO2 scrubbers used on boilers also enable the control of the dust emissions.
For new boilers, only the use of ESP is considered to be BAT to reduce dust emission levels. For
existing boilers, the combination of ESP and scrubbers is necessary. SO 2 scrubber combined with an
3
ESP can achieve about 15 mg/Nm of dust emissions.
The following table gives an overview of BAT associated dust emission levels for Kraft pulping
process.
Paper pulp production is not identified as a large emitter of BC according to references [9], [10] and
[12]. However BC emission data are scarce. If BC is present in dust, BAT measures described just
above for dust which are efficient for fine particles, are also efficient for BC.
Table 5: associated dust emission levels with BAT to reduce emissions in the Kraft pulping
process [1], [2]
3
(mg/Nm )
Lime kiln ESP dust: 30 – 50
Recovery boilers
ESP and SO2 scrubbers dust: 30 – 50
(5% O2)
1
dust: 10 – 30
2
Auxiliary boilers ESP dust: 10 – 40
3
dust: < 5
1
feed with coal or biofuel or gas oil
1
feed with heavy fuel oil
3
feed with gas
Sulphite process
In sulphite pulp mills, dust emissions come from different sources, mainly the lime kiln, the auxiliary
boiler and the recovery boiler. Emissions can be controlled using the same systems as for the Kraft
process.
The following table gives an overview of BAT associated dust emission levels for sulphite pulping
process.
Paper pulp production is not identified as a large emitter of BC according to references [9], [10] and
[12]. However BC emission data are scarce. If BC is present in dust, BAT measures described just
above which are efficient for fine particles, are also efficient for BC.

Table 6: associated dust emission levels with BAT to reduce emissions in the sulphite pulping
process [1], [2]

(mg/Nm )
Recovery boilers
ESP and SO2 scrubbers dust: 5 - 20
(5% O2)
1
dust: 10 – 30
2
Auxiliary boilers ESP dust: 10 – 40
3
dust: < 5
1
feed with coal or biofuel
1
feed with heavy fuel oil
3
feed with gas

The installation of SNCR on recovery boilers, main source of NOx emissions, is considered as
emerging reduction technique in pulp industry, as it is a new application of this common technique.
The investment for a complete installation of SNCR (NOxOUT process) on a recovery boiler (black
liquor load: 1600 t dry solids/day) is about 2.2 - 2.8 Meuros.
Due to its low rate of use, no emerging techniques are identified for emissions reduction in the sulphite
process [1].
SO2 scrubbers on recovery boilers come usually as a package from the supplier. Investment for a
bleached Kraft mill with a production capacity of 250,000 and 500,000 t/y amount to 7.2 Meuros and
10.4 Meuros respectively. They include scrubber, scrubber liquor pumps, circulation pumps,
electrification and instrumentation. Operating costs amount to 0.58 Meuros/y and 0.92 Meuros/y
respectively [1][1]. Mis en forme : Anglais (États Unis)
The investment to add a SNCR process to the bark boiler for the same production capacit y plant is
about 0.7-1.15 Meuros. The investment costs include injection equipment, pipes, pumps, tanks and
rebuild/adoption of the boiler. The operating costs are mainly due to urea consumption, about 1-2 kg
urea is required per kg NOx removed [1][1]. Mis en forme : Anglais (États Unis)
The installation of electrostatic precipitator costs about 3-4 Meuros for the bark boiler (auxiliary boiler)
and 5-6 Meuros for the lime kiln. Operating costs are less than 0.3 Meuros/y in both cases [1][1]. Mis en forme : Anglais (États Unis)
Investments for low NOx technology in auxiliary boilers or lime kilns are 0.5 - 0.8 Meuros.

[1] Reference document on Best Available Techniques in the pulp and paper industry, December
2001.
[2] EPA 42 – volume 1 chapter 1, September 1998.
[3] Auswertung von staub- und Feinstaubemissionsdaten der Datenbank nordrhein-westfälisher
Emissionserklärungen, LUA NRW, 2003.
[4] Arrêté du 3 avril 2000 relatif à l’industrie papetière, JO 17-06-2000.

[5] Comments from Almut Reichart, UBA, 12/2008

[6] “Compilation of the answers-to-questions-and proposal of EGTEI secretariat.doc”, EGTEI,
02/2009.

7.16 Nitric acid production

7.16.1 Coverage
Nitric acid (HNO3) is one of the most produced chemical product. Emissions to the atmosphere from
nitric acid production which cause the greatest concern are nitrous oxide (N2O) and nitrogen oxides
(NOx) emissions. The Gothenburg Protocol deals with transboundary air pollution and particularly with
acidification and eutrophication. It sets emission ceilings for sulphur, nitrogen oxide, VOC, ammonia
and dust but it does not cover N2O which is a green house gas with high global warming potential.
Hence, this chapter is mainly focused on NOx emission reductions.

HNO3 is produced from ammonia (NH 3), which is evaporated, filtered and oxidised to form nitric oxide
(NO). Ammonia filtration is necessary in order to remove all dust. It avoids interaction between dust
particles and catalysts on which ammonia oxidation takes place.
The NO formed during the oxidation is then also oxidised to form nitrogen dioxide (NO2). NO2 is then
absorbed in H2O to form nitric acid and nitric oxide. The absorption process is an important source of
NOx emissions; hence NOx need to be controlled and reduced. Different techniques are available to
reduce these emissions.

Primary measures
Major NOx emissions come from the step of formation of HNO 3. One of the different applicable
techniques to reduce NOx emissions involves the optimisation of the absorption stage. The more the
absorption is efficient, the more HNO3 is formed and the less NOx is emitted [1].
The efficiency increase of this absorption is based on the optimization of 3 parameters; the
temperature, the pressure and the contact between NOx, O2 and H2O.
due to the reaction exothermia, heat removal is needed to optimise the temperature process.
The absorption stage takes place in the first third of the column, thus heat removal can be
applied before the column.
high pressure increases the efficiency of the absorption and then nitric acid formation. It also
reduces the formation of NOx.
optimising the contact in the absorption tower mainly means changing the tower design. The
volume, the number of trays and the residence time are the main parameters to play with so as
to optimise the absorption. The longer the residence time is, the more NOx is recovered and the
more nitric acid is formed. The increase of the number of trays and of the volume enhances the
nitric acid formation too.
3
Tail gas concentration level of 82 – 103 mg/Nm is technically feasible with completely optimised
absorption (heat removal, high pressure, optimised contact).
The HNO3 yield can also be increased by addition of H 2O2 to the last absorption stage. It avoids the
implementation of a SCR [1].
Secondary measures
NOx emissions can be reduced by a tail gas treatment, such as a combined N2O and NOx abatement
technique or a SCR can also be used.
The combined N2O and NOx abatement technique consists of 2 catalyst layers. In the first layer, N 2O
is reduced in N2 and O2. In the second layer, NOx is reduced by addition of NH 3 (comparable to a
SCR) and N2O further decomposition is also taking place. This process can lead to a NOx abatement
of 99 %.The process is applicable for nitric acid plants with a tail gas temperature of more than 400
degree Celsius [1].

For installations with a tail gas temperature of more than 340 degree Celsius N 2O and NOx emissions
can be reduced in a combined N2O and NOx abatement system with the addition of hydrocarbons. [4].
As in the combined N 2O and NOx abatement process, there are 2 catalyst layers. In the first one, NO x
is removed in reacting with NH 3 and N2O is removed by a catalytic reduction with hydrocarbon (natural
gas or propane) in the second step. Similar emission levels as in the N 2O and NOx combined
abatement technique can be expected. [1].
The following table gives an overview of BAT associated NOx emission levels for nitric acid production.
Table 1: associated NOx emission levels with BAT to reduce emissions in nitric acid
production.
Associated
emission level
with BAT
3 1
(mg/Nm )
New plants
Optimisation of the absorption stage, 10 - 154
Nitric acid production Combined NOx and N2O abatement technique ,
SCR, Addition of H2O2 to the last absorption stage Existing plants
2
10 – 185
1
emissions were converted from ppmv to mg / Nm3 using: 1ppmv = 2.05 mg NO2 / Nm3.
2
up to 307 mg/Nm3, where safety aspects due to deposits of AN restrict the effect of SCR or with addition of H 2O2 instead of
applying SCR.

There is no emerging technique available to reduce NOx emissions in HNO3 production [1].

The investment of a combined N2O and NOx treatment unit is about 1.7 Meuros. A comparison of
various N2O reduction strategies does not show a significant difference in cost effectiveness and the
cost per tonne HNO3. Operating costs are between 0.71-0.87 euros per tonne CO2-eq reduced and
0.98 – 1.20 euros per tonne HNO3 produced.
There is no available information about the cost of the hydrocarbon addition technique.
The total cost for a SCR technique is around 1.3 USD per tonne HNO 3 produced. This estimation was
made in 1998 assuming certain price of catalyst and fuel, which are now significantly different. [1].
The specific cost of the implementation of the addition of H 2O2 to the last absorption stage is 2.5 USD
per tonne HNO3.

[1] Reference document on Best Available Techniques for the manufactures of large volume
chemicals – ammonia, acids and fertilizers, August 2007.
[2] Comments from Birgit Brahner, German Federal Environment Agency, 12/2008.
02/2009.
[4] Comments from Thomas Krutzler, UBA Austria, March 2009.
[5] EGTEI-State of progress.doc”, for WGSR, March 2009.

7.17 Sulphuric acid production1

7.17.1 Coverage
The production of sulphuric acid (H 2SO4) is in terms of quantities the most important production of the
industrial chemical production. The production of H 2SO4 varies from the SO2 sources.
The emissions to the atmosphere from sulphuric acid production which cause greatest concern are
sulphur dioxide (SO2) emissions. This chapter covers the chemical production of sulphuric acid.

H2SO4 is produced from sulphur dioxide or elemental sulphur. Elemental sulphur is derived from
desulphurisation of natural gas or crude oil. SO2 is derived from flue gas process, e.g. SO2 gases from
sulphur, the roasting of zinc and /or lead minerals, regeneration of spent acids, non ferrous metal
production, or waste gas incineration, etc.
SO2 is first oxidised on catalysts to SO3. Catalysts used are based on vanadium compounds, platinum
and iron oxides [6].
SO3 is then absorbed in H 2SO4 to form sulphuric acid. High SO2 emission levels come from this part of
the process; hence measures to reduce SO2 emissions have to be used.
Mis en forme : Police :Gras, Anglais

SO2: [1][1]
(États Unis)
The major SO2 emissions come from the absorption process tail gas. SO2 emissions depend on the
conversion rate of the process. Process optimisation can be considered as the best available
technique to reduce emissions.
Different techniques to increase SO2 conversion rate can be combined in order to achieve BAT
associated emission levels.
A double contact/double absorption process improves the conversion yield of SO 2 from the tail gas. A
change from a single absorption to a double absorption can significantly reduce SO 2 emissions.
The addition of a fifth bed catalyst in the double contact process can increase the conversion rate to
99.9 %. This technique is generally applicable for double contact plants, provided that sufficient room
is available [1]. Usually applying double contact process maximum conversion rate is 99.8 % in a
steady-state operation, maximum conversion rate 99,6% under transient operation conditions. But this
technique’s application in an existing plant has two main difficulties: the high cos t of the investment
and the high cost of the operation, owing to the need of external heating , owing to the difficulty of
reaching the proper temperatures for the operation of catalyst and to the fluodynamic characteristics of
the installed blowers [6].
The use of a Cs promoted catalyst can also increase the conversion rate of SO 2. Indeed, Cs promoted
catalysts can be used at lower temperature (380 – 620°C) than conventional catalysts (420 – 660°C).
The replacement of brick-arch converters, too porous, can lead to an increase of SO 2 conversion rate.
The use of wet catalysis process enables the conversion of wet SO 2 gases.
Finally, a regular maintenance of utilities and replacement of catalysts is necessary to mai ntain a high
conversion rate.
1
The information included in this subchapter is based on the BREF [1] on large volume chemicals. Some new
information from the BREF non ferrous metal industry, which is currently under revision at the Institute for
Prospective Technological Studies in Seville (IPTS), should be available in a near term. Mis en forme : Anglais (États Unis)

Secondary measures can also be applied.

Tail gas can be scrubbed using an aqueous ZnO solution or NH3 solution, or other alkaline solutions
such as sodium hydroxide, as well as hydrogen peroxide. These scrubbing can provide by-products
that can be used on-site or sold [4].Erreur ! Source du renvoi introuvable.
The BAT to reduce SO2 emissions is a combination of the formerly cited processes and reduction
techniques permitting to achieve the emission levels detailed in the following table.
The following table gives an overview of BAT associated SO2 emission levels for sulphuric acid
production.
Table 1: associated SO2 emission levels with BAT to reduce emissions in sulphuric acid
production
Associated
emission level with
BAT
3 1, 2
(mg/Nm )
Existing installations :
30-680
Sulphur burning, double contact/double absorption
New installations :
30-340
Sulphuric acid production
Other double contact/double absorption 200-680
Single contact/single absorption 100-450
Other 14-170
1
This level might include the effect of tail gas scrubbing.
2
Expressed as daily average value.

No data available.

The addition of a fifth bed to a double contact process needs an investment of about 1 million euros.
The specific cost related to SO2 reduction is 629 euros per ton SO2 reduced [1].
The investment cost of the application of promoted-Cs catalyst in a double contact process is 21 700
euro/y more than the original investment for traditional catalyst. The specific cost related to SO2
reduction is 12 euros per ton SO 2 reduced. This cost increases to 930 euros per ton SO2 reduced for a
single contact process [1].
The following table gives an overview of the costs and SO 2 conversion rate for different abatement
techniques in sulphuric acid production [8].

Table 2: cost and operational data of techniques used to control SO2 emissions in sulphuric acid production.
SO2-Conversion Costs SO2 Annualised SO2

Construction
Nr. Capacity % SO2 average (%) €/t SO2 €/t H2SO4 avoided costs unabated
(t H2SO4/d) content before after before after abated additionaly (t/year) (€/year) (t/year)
4 bed SC/SA Base case A1 98.00 - 0 0 0 0 1143
3 4 bed SC/SA + Cs in bed 4 98.00 99.10 3 0.02 628 1 763
1 4 bed SC/SA 4 bed DC/DA 98.00 99.60 1 317 13.76 914 1 203 985
5-7
2 4 bed SC/SA 4 bed DC/DA + Cs in bed 4 98.00 99.70 1 159 12.87 971 1 125 848
4 4 bed SC/SA + TGS Peracidox 98.00 99.87 1 048 12.80 1 068 1 119 881
5 250 4 bed SC/SA + TGS (alkaline) 98.00 99.87 1 286 15.70 1 068 1 373 446
4 bed DC/DA Base case A2 99.60 - 0 0 0 0 228
6 4 bed DC/DA + Cs in bed 4 99.60 99.70 367 0.24 57 20 858
7 9 - 12 4 bed DC/DA 5 bed DC/DA + Cs in bed 5 99.60 99.80 3 100 4.03 114 352 656
8 4 bed DC/DA + TGS Peracidox 99.60 99.94 3 910 8.68 194 759 562
9 4 bed DC/DA + TGS (alkaline) 99.60 99.94 6 636 14.73 194 1 287 390
4 bed SC/SA Base case B1 98.00 - 0 0 0 0 2286
12 4 bed SC/SA + Cs in bed 4 98.00 99.10 5 0.04 1 257 6 285
10 4 bed SC/SA 4 bed DC/DA 98.00 99.60 867 9.06 1 829 1 584 685
5-7
11 4 bed SC/SA 4 bed DC/DA + Cs in bed 4 98.00 99.70 835 9.27 1 943 1 622 590
13 4 bed SC/SA + TGS Peracidox 98.00 99.87 718 8.77 2 137 1 535 220
500
14 4 bed SC/SA + TGS (alkaline) 98.00 99.87 883 10.78 2 137 1 886 839
4 bed DC/DA Base cas C1 99.60 - 0 0 0 0 457
15 4 bed DC/DA + Cs in bed 4 99.60 99.70 363 0.24 114 41 278
9 - 12
16 4 bed DC/DA 5 bed DC/DA + Cs in bed 5 99.60 99.80 1 559 2.03 228 354 762
17 4 bed DC/DA + TGS Peracidox 99.60 99.94 2 209 4.90 389 858 349

4 bed DC/DA Base Case C2 99.60 - 0 0 0 0 914
19 4 bed DC/DA + Cs in bed 4 99.60 99.70 356 0.23 228 81 023
20 1000 9 - 12 4 bed DC/DA 5 bed DC/DA + Cs in bed 5 99.60 99.80 1 020 1.33 455 464 258
21 4 bed DC/DA + TGS Peracidox 99.60 99.94 1 359 3.02 777 1 055 922
Hypothesis:
the conversion rate depends on specifications (design, installations, concentration, source of SO2). Precision 0,1%.
SO2 content: 5 - 7%: calculated with 5% and 9 - 12% calculated with 10%,
O2 content: 5 - 7% SO2 + 6 - 9% O2 and 9 - 12% SO2 + 8 - 11% O2,
lifetime for all installations: 10 years,
fixed operation costs: 3%,
interest rate: 4%,
price H2SO4: 20 €/t ex works
labour costs: 37 k€/man-year
utilities for TGS Peracidox and alkaline Absorptions: +30% capital investment costs
warranted SO2-content after TGS: < 200 mg SO2/Nm³ = < 70 ppm SO2
steam price: 10 €/t
SC = single contact ,SA = single absorption, DC = double contact, DA = double absorption


[1] Reference document on Best Available Techniques for the manufactures of large volume
chemicals – ammonia, acids and fertilizers, August 2007.
[2] Comments from Birgit Brahner, German Federal Environment Agency, 12/2008.
02/2009.
[4] Comments from Erik Kiekens, PVS, European sulphuric acid association, March 2009.
[5] Comments from Dawn Christensen, Ineos, European sulphuric acid association, March 2009.
[6] Comments from Aldo Zucca, Portovesme, European sulphuric acid association, March 2009.
[7] Comments from Thomas Krutzler, UBA Austria, March 2009.
[8] Retrofitting of old plants, ESA expert group, May 2009.


7.18 Municipal, medical and hazardous waste incineration
7.18.1 Coverage
This section addresses the incineration of municipal (or domestic) solid waste, hazardous and medical
wastes as well as the incineration of sludges from wastewater treatment.
Municipal solid waste (MSW) mainly consists of paper and paperboard, glass, metals, plastics, rubber,
leather, textiles, wood, food waste, yard waste, and miscellaneous inorganic waste [1].
Hazardous waste is mainly generated in industrial production processes (e.g. ashes, sludges, and
other production waste), energy generation, civil engineering and building activities (e.g. demolition
waste, construction site waste, and road construction waste) and by waste incineration (fly ashes) [1].

Municipal solid waste, sewage sludge and hazardous waste can i. a. be treated in incineration plants.
Municipal solid waste is mainly incinerated in public owned waste incineration plants, although a
certain amount is burned at industrial incineration sites [1]
Different types of thermal treatments are applied to the different types of wastes, however not all
thermal treatments are suited to all wastes. This paragraph describes the main technologies for the
thermal treatment of wastes [1].
Municipal solid waste can be incinerated via several main combustion systems including moving
grate and fluidized bed [1]. Fluidized bed technology requires MSW to be of a certain particle size
range - this usually requires some degree of pre-treatment and/or the selective collection of the waste
[3].
For the incineration of hazardous and medical waste, rotary kilns and grate incinerators are most
commonly used, but fluidized bed incinerators are also applied.
Incineration of sewage sludge takes place in rotary kilns, multiple hearth, or fluidized bed
incinerators, but co-combustion in grate firing systems, coal combustion plants and industrial
processes is also applied [1], [2], [3]. Sewage sludge has to be dried or mechanically dehydrated
before combustion and often additional firing is required to ensure stable combustion.
Grate technology. Municipal waste is the main application for these incinerators, which can be
designed to handle large volumes of waste [2]. In Europe approximately 90% of installations treating
MSW uses grates.
Different grate firing systems such as rocking grates, reciprocating grates, travelling grates, roller
grates (each of them and water cooled or not) have been developed and can be distinguished by the
way the waste is conveyed through the different zones in the combustion chamber. The different grate
systems have to fulfill special requirements regarding primary air feeding, conveying velocity and
raking, as well as mixing of the waste. Main additional features are good control characteristics and a
robust construction to withstand the severe conditions in the combustion chamber [1].
Fluidized bed Incinerators are suitable only for reasonably homogeneous materials and are
therefore the main designs for the incineration of sewage sludge, but also for mechanically or
mechanically-biologically pre-treated waste streams [2].
Preheated air is introduced into the combustion chamber via openings in the bed plate forming a
fluidized bed with the sand contained in the combustion chamber. The waste is fed to the reactor via a
pump, a star feeder or a screw-tube conveyor. In the fluidized bed, drying, volatilisation, ignition, and
combustion take place at a temperature between 850 and 950 °C. Above the fluidized bed, a
secondary combustion zone is created to ensure a retention time of more than two seconds at a
temperature above 850 °C. When the air supply to the fluidized bed is under-stoichiometrical (lambda

<1), the bed temperature is significantly lower, e.g. 650°C. In this case, only gasification takes place in
the bed itself, and most of the heat is being generated in the secondary combustion zone, i.e. above
the fluidized bed, by gas phase oxidation reactions [1].
Fluidized bed incineration systems have the advantage of easy and quick stop of waste supply and
hot start behaviour and the advantage of a lower temperature which leads to lower NOx formation [1],
[2]. However, in case of a complete shut-down (e.g. with the aim of bed material removal or
maintenance work to be done) or a cold start, it takes significantly longer for a fluidized bed system to
cool down or to heat up than for a grate system, as the whole sand load has to be cooled down or
heated up to operation temperature
Rotary kiln. In rotary kilns, almost any waste, regardless of type and composition, can be incinerated
and temperature restrictions for operation are not as stringent as in the case of fluidized bed or
multiple hearth incinerators [1]. They have the benefit of good waste agitation and achieve good
burnout, provided waste residence time in the furnace is adequate. They can be used in combination
with other designs to provide additional ash burnout [2]. The rotary kiln consists of a cylindrical vessel
slightly inclined on its horizontal axis. The waste is conveyed through the kiln by gravity as it rotates. In
order to ensure complete destruction of toxic compounds, a secondary combustion chamber is
generally necessary [Erreur ! Signet non défini.1].
Multiple hearth furnaces are mainly applied to the incineration of suldges. Sewage sludge is fed at
the top of the furnace and moves downwards through the different hearths counter-current to the
combustion air, which is fed at the bottom of the furnace. The upper hearths of the furnace provide a
drying zone, where the sludge gives up moisture while the hot flue gases are cooled. The central
hearths are in charge of the incineration, and the lower hearths ensure complete burnout. The
incineration temperature is limited to 980 °C, because above this temperature the sludge ash fusion
temperature will be reached and clinker will be formed. In order to prevent leakage of hot toxic flue
gases, multiple hearth furnaces are always operated at a slight vacuum pressure [8]
Other processes have been developed that are based on the decoupling of the phases which also
take place in an incinerator: drying, volatilisation, pyrolysis, carbonisation and oxidation of the waste;
gasification using gasifying agents such as steam, air, carbon-oxides or oxygen is also applied.
7.18.3.1 SO2
Sulphur dioxide as well as HCL and HF is formed during combustion of sulphur-(chloride- and
fluoride)-containing compounds which are found in waste. Their amount is mainly determined by the
amount of sulphur-(chloride- and fluoride) containing compounds present in the waste but operation
conditions and incineration technology applied may also have a minor impact.
Raw gas concentrations of SO2 typically are in a range from 400 to 1000 mg/Nm³, clean gas
concentrations are mostly required to be considerably lower [1], [3], making flue gas treatment
indispensable.
SO2 is removed in general from the flue gas by means of wet scrubbers, spray-dry scrubbers and dry
scrubbers.
The use of primary measures such as fuel selection, waste selection or segregation techniques, are
considered to be BAT [2].
The three main techniques, web scrubbing, semi-dry and dry scrubbing are considered to be BAT for
the removal of SO2 in the incineration of sewage sludges, municipal and medical waste [2].

3
For wet scrubbers and semi-wet FGTsemi-dry scrubbers, concentration < 20 mg/m can be achieved
and water consumption is needed (and effluent may be generated). Reduction rates of 96-98.4 % are
3
achievable. For dry scrubbers, concentration achieved can be < 40 20 or to < 420 mg/m can be
achieved depending on the reagent used.
Table 1: Emission sources and selected BAT SOx control measures with associated emission
levels in waste incineration
Operational SOx emission level
Combination of control 12
Emission source associated with BAT
measures 3
(mg/Nm )
Domestic or municipal waste incineration
Grate incinerator Dry scrubber 1- 40 [3][3]
Rotary kiln Spray dry scrubber 1 - 40
Fluidized bed combustion Wet Scrubber 1 - 40
Industrial waste incineration (hazardous and medical waste)
Grate incinerator Dry scrubber 1 - 40
Rotary kiln Spray dry scrubber 1 - 40
Incineration of sludges from waste-water treatment
Rotary kiln Dry scrubber 1 - 40
Multiple hearth furnace Spray dry scrubber 1 - 40
1
2
The ELV of the EU waste incineration directive for SO2 is 50 mg/m³
7.18.3.2 NOx
Nitrogen oxides are emitted from incineration plants. In many cases they are measured using
continuous emission monitors. Emissions at modern plants are reported to be generally in the range
3
between 30 and 200 mg/Nm . (clean gas, daily average, 11% O2 [3]).
Emissions of NOx can generally be lowered by reducing the amount of incinerated waste. This can be
accomplished through various waste management strategies, including recycling programmes and
composting of organic materials.
Nitrogen oxides are formed predominantly as NO and NO2. Contrary to high temperature processes,
most Most of the nitrogen oxides generated during waste incineration (furnace temperature between
800 and 1200 °C) originate from the nitrogen contained in the waste (fuel- NOx) [1]. Thermal NOx
concentrations are lower than fuel NOx concentrations. Therefore, the reduction efficiency of primary
measures mainly aimed at limiting fuel NOx formation is generally limited, as a majority of nitrogen
oxidesNOx originates from fuel bound nitrogen and as the amount of fuel bound nitrogen converted to
nitrogen oxides can only be influenced to a limited extent through changes in plant design and
operation [1]. However, primary measures are generally of great importance for reducing the formation
of NOx at the combustion stage. They mainly relate to the management and preparation of wastes,
and particularly to the thermal treatment applied [3].
Primary measures (limiting emissions at the source in opposition to secondary measures reducing end
of pipe emissions) have been developed to reduce NOx emissions at source during the combustion
process by regulating flame characteristics such as temperature and fuel-air mixing. Secondary
measures operate downstream of the combustion process and remove NOx emissions from the flue
gas.

For the incineration of sewage sludges as well as municipal and medical waste the use of primary
measures such as flue-gas recirculation, air-staged combustion, fuel selection, low NOx burners in
combination with secondary measures (e.g., SCR, SNCR) is considered to be BAT.
In general SCR is considered BAT where higher NOx reduction efficiencies are required (i.e. raw flue
gas NOx levels are high) and where low final flue-gas emission concentrations of NOx are desired.
Actually, SCR is a proven technology in the waste incineration sector, which allow to achieve high NOx
3
reduction rates (typically over 90%) [1] [3] [1], [3] and NOx emission of below 50 mg/m [11].
For SNCR ammonia and urea injection are suitable and considered to be BAT. Reducing NOx by
SNCR to 75% requires a higher addition of the reducing agent. With application of SNCR NOx
3
emission concentrations of 70 mg/m (daily average) [1], [3] can be reached.
An effective emission control of NOx via SCR or SNCR can result in increased NH3-emissions (NH3-
slip), which again can be converted to NOX. To achieve a low level of total nitrogen emissions also a
3
NH3-emission control (NH3 emissions < 10 mg/m are achievable) is necessary [3].
Table 2: Emission sources and selected BAT NOx control measures with associated emission
Operational NOx emission level

Combination of control 12
Emission source associated with BAT
measures 3
(mg/Nm )
Waste incineration SCR 40-100
no SCR 120-180
1
2
The ELV of the EU waste incineration directive for NOX is 200-400 mg/m³ (depending on plant capacity and
existing/new status)
Effective control of NOx abatement systems, including reagent dosing contributes to reducing NH3 emissions. Wet
scrubbers absorb NH3 and transfer it to the wastewater stream. BAT are considered NH3 emissions <10 mg/m³
(BREF Split view: <5)
Dust emissions from waste incineration plants mainly consist of the fine ashes from the incineration
process that are entrained in the gas flow [3].[3]. Dust is normally measured continuously with
3
reported emissions after treatment of between <0.05 and 15 mg/Nm (11% O2) [3]).
Dust removal techniques can be divided into pre-dedusting and end-dedusting. Whereas the main
purpose of pre-dedusting is to collect residues of different composition separately and to avoid
operational problems in down-stream equipment, the main purpose of end-dedusting is to reduce final
dust emissions
Dry and wet electrostatic precipitator and fabric filters are the mainly used three types for removing of
particulate matter in flue gases. ESPs are effective in collecting dust with particle size in the range of
0.1 µm to 10 µm, and their overall collection efficiency can be 95 to 99 percent [1].
Fabric filters (FF) are considered to be BAT for the incineration of sewage sludge as well as municipal
and medical waste. They are a proven technology and when correctly operated and maintained
3
provide reliable abatement of particulate matter to below 5 mg/m . Removal efficiencies are very high
for a large range of particle size.
In general, electrostatic precipitators (ESPs) either wet or dry are not capable of abating particulate
matter to the same extent as fabric filters [2]. In combination with wet scrubbers they are considered to
be BAT. Depending on the design system and the place in the flue gas treatment system (pre- or end-
3
dedusting), particulate emission concentration values of 5 to 25 mg/m can be reached [Erreur !

Signet non défini.3]. With a wet ESP which is a specific version of the ESP the cleaning takes place
continuously by a water flow. This version is applied as end-dedusting after a wet scrubber. Very low
3
particulate matter of below 5 mg/m can be reached [3].
Waste incineration is not identified as a large emitter of BC according to references [12], [13] and [14].
However BC emission data are scarce. If BC is present in dust, BAT measures described just above
efficient for fine particles, are also efficient for BC.
Combination of control Operational dust emission level

Emission source 12 3
measures associated with BAT (mg/m )
FF,
ESP
Waste incineration In general the use of fabric filters gives 1-5 Mis en forme : Anglais (États Unis)
the lower levels within this emission
range. Mis en forme : Anglais (États Unis)
1 Mis en forme : Retrait : Gauche : 0
cm, Espace Avant : 0 pt, Avec coupure
load situation. For peak load, start up and shut down periods, as well as for operational problems of the flue gas mots, Ne pas ajuster l'espace entre le
cleaning systems, short-term peak values, which could be higher, have to be regarded texte latin et asiatique, Ne pas ajuster
2
The ELV of the EU waste incineration directive for dust is 10 mg/m³ l'espace entre le texte et les nombres
asiatiques
Mis en forme : Police :(Par défaut)
Times New Roman, 9 pt
Table 4: cost data for different abatement techniques [1], [3]
Investments costs (EURO) Specific costs of maintenance (EURO/t)

Control options
Throughput per line (t/yr) Throughput per line (t/yr)
75,000 100,000 150,000 75,000 100,000 150,000
SCR 1,200,000 1,500,000 2,000,000 0.30 0.30 0.30

SNCR 700,000 800,000 1,000,000 0.19 0.16 0.13
Wet dedusting system 1,500,000 2,000,000 2,500,000 0.30 0.30 0.30
Dry flue gas cleaning
1,725,000 2,175,000 3,000,000 0.23 0.22 0.20
with adsorption
ESP 1,000,000 1,200,00 1,600,000 0.27 0.24 0.21
Dry flue gas cleaning
1,150,000 1,450,000 2,000,000 0.15 0.15 0.13
with fabric filter

Guidance document on control techniques for emissions of sulphur, NOx, VOCs, dust and black
carbonfrom stationary sources

[1] DFIU/IFARE: Draft Background document on the sector Waste Incineration. In preparation of
st
the 1 EGTEI panel Meeting, Paris, June 2002
[2] UK Environment Agency: Guidance for the incineration of waste and fuel manufactured from or
Including waste, UK Technical Guidance : S5.01, July 2004
[3] European Commission: Reference Document on the Best Available Techniques for Waste
Incineration, August 2006
[4] Donnelly, J. R.: Waste Incineration Sources - Refuse, in: Buonicore, A. J.; Davis, T. W. (eds.):
Air Pollution Engineering Manual, New York, 1992
[5] Brunner, R. C.: Waste Incineration Sources - Sewage Sludge, in: Buonicore, A. J.; Davis, T. W.
(eds.): Air Pollution Engineering Manual, New York, 1992
[6] N.N.: Mitverbrennung von Klärschlamm im Kohlekraftwerk, in: Abfallwirtschaftsjournal,
6 (1994) 12
[7] Stäubli, B.; Keller, C.: Stoffflußanalyse bei zwei Klärschlammverbrennungsanlagen, in: Müll und
Abfall, 25 (1993) 2
[8] Rentz, O; Schleef, H.-J.; Dorn, R.; Sasse, H.; Karl, U.: Emission Control at Stationary Sources
in the Federal Republic of Germany, Sulphur Oxide and Nitrogen Oxide Emission Control,
UFOPLAN-Ref. No. 104 02 360, Karlsruhe, August 1996
[9] Rentz, O; Ribeiro, J.: Operating experience with NOx Abatement at Stationary Sources, NOx
Task Force, Karlsruhe, 1992
[10] R. Meij, B. Winkel: The emissions and environmental impact of PM10 and trace elements from
a modern coal-fired power plant equipped with ESP and wet FGD, Fuel Processing 85, 641-
656.
[11] J. Stubenvoll, S. Böhmer, I. Szednyj: State of the Art for Waste Incineration Plants, Federal
Environment Agency-Austria, Vienna, November 2002

7.19 Industrial wood processing

7.19.1 Coverage
The wood processing industry is composed by many activities. Sawmill, flooring, panel production,
furniture production are the main activities covered by this wide sector.
Wood processing is mainly a source of dust emissions.
This chapter covers the different activities of wood processing. Although, wood processing industries
use wood to fed boilers, wood combustion is not included in this chapter.

Wood processing activities can be separated between primary and secondary processing steps.
Primary processing covers raw wood processing activities while secondary processing covers
activities transforming primary processed wood.
During primary processing, wood harvest is cut, barked, cross cut or pressed. Then, wood is
secondary processed into wooden floor, panels, furniture, toys, etc.
Different types of wood are used in wood processing industry; they are presented in the following
table. [1]
Table 1: wood processing activities (sources of dust emissions) associated to types of wood
used
Moist
Process Dry wood Timber Panel
wood
Wood harvest cut X X
Slicing X X
Primary cut X X
Storage of fine sawdust and chips X X
Defibration, milling and chipping X X X
Drying of laminations, particles and sawdust X X X
Screening
Seasoning of timber and drying of panels X X
Pressing of panels X X
Cutting X X X
Sanding X X X
Other machining (edging, planning, etc.) X X X
Workshop cleaning X X X X
Dust emission levels and characteristics depend on 2 main factors:

type of wood processed,
water content of the wood processed.
Therefore, dry wood, moist wood, timber and panel are separated in the previous table.

7.19.3 Available Techniques, Associated Emission Level (AEL)
Techniques used to reduce dust emission levels depend on particle sizes, which themselves depend
on the process applied and the wood used. Therefore, it is necessary to distinguish primary
processing from secondary processing.
Primary processing steps [1]

Primary processing steps are essentially debarking, slicing, primary cutting, routing, milling, chipping
and pressing. Those processes are not major sources of fine particle emissions. Emissions are mainly
composed by particles with a diameter of more than 700 µm except from the routing process which is
a source of particles with a diameter of more than 100 µm.
Debarking, slicing, primary cutting and routing:
During these processes, dust emissions are mainly coarse particles. To reduce dust emission levels, a
spray of water on the trunk can be considered as sufficient during the debarking process which is a
source of low emission levels while cyclones can be used to control dust emissions from slicing,
primary cutting and routing which are sources of higher emission levels.
Milling and chipping:
In most of the cases, the mill grinder is open and dust emission levels are high. However emissions
can be collected by an aspiration system and dust emission levels can be reduced by the use of fabric
filters.
Pressing:
A wet electrostatic precipitator can be used to reduce dust emission levels from collected emissions of
the pressing process.
Secondary processing steps [1]

Secondary wood processing steps are important issues concerning fine particle emissions. The higher
level of PM10 and PM2,5 emissions can be explained by the fact that the wood used in secondary
processing steps is dry.
Drying, sanding and edging processes are major sources of high dust emission levels. Mainly fine
particles are emitted during these processes, thus emissions should be collected and treated. Multi-
cyclones or a combination of cyclones and wet scrubbing system can be used to treat emissions from
drying systems. Fabric filters can be used to reduce dust emission level from sanding or edging.
As heated air used in the dryers usually comes from boilers fed by wood fuel, dust come also from the
boiler and emission levels need to be reduced before entering the dryer.
Collected dust from fabric filters or other dry dust reduction techniques should be recycled and re-used
in the process as far as possible or used as biomass fuel. The collected dust or sawdust should be
transported between the different process steps in closed conveyor equipped with an aspiration
system and a dust treatment system.
Emissions from sawdust storages are mainly fugitives. Storages have thus to be protected from the
wind and handled carefully. Good housekeeping may also contribute to reduce dust emissions.
Dust emissions can also be abated using electrostatic filters, but this technique is very expensive and
does not seem to be cost effective in the wood processing industry. However it can be considered as
available techniques for new installations while fabric filters can be considered as available techniques
in existing installations for most emitting processing steps.
Panel production can be separated from other wood processing industries. In wood processing
industries, small companies of less than 20 employees are numerous while panel production
establishments are significantly larger in size. Therefore, secondary measures to reduce dust
emission levels are more cost effective in panel industry than they are in other small wood processing
industries.

Table 2: associated dust emission levels with available techniques to reduce emissions in
panel production industry [1]
Associated emission level

(mg/Nm )
Cyclone 100 – 230
Dryers in particle board Wet scrubbing system 15 – 75
production
Combination of cyclone and wet
25
scrubbing system
Dryers in fiberboard production Cyclone 7
Machining in fiberboard
Bag filters 0,03 – 0,6
production
Dryers in oriented strand board Cyclone filter 60 – 70

No emerging technique is considered for the wood processing industry.

The following table gives an overview of the costs for different abatement techniques in particle board
industry.
Table 3: cost of techniques to control PM emission in particle board industry [2]
1
Technique Investment ( Euros/1000m² of board)
Cyclone 5.4
Wet Cyclone 7.2
Fabric Filters 21.6
Dry ESP 28.8
Wet ESP 32.3
1
Conversion rate used: 1 C$/1000m² = 7.19 €/1000m².

[1] Technique de dépoussiérage utilisées dans l’industrie en 2006, ADEME, décembre 2007 Mis en forme : Français (France)
[2] Carte routière technologique – panneaux de particules, Strategis Canada, 1998.
[3] EGTEI-State of progress.doc”, for WGSR, April 2009.


7.20 Petrol distribution (from the mineral oil refinery dispatch station
(petrol) to service stations including transport and depots (petrol))
7.20.1 Coverage
Activities covered relate to the transport and distribution of petrol from mineral oil refinery dispatch
stations or terminals, to service-stations often via intermediate storages. The terminal is any facility
which is used for the storage and loading of petrol onto road tankers, rail tankers, or vessels, including
all storage installations on the site of the facility. A refinery may have its own terminal fed by pipeline in
close proximity but external to the refinery site or a dispatch station which is located on the refinery.
The service-station is an installation where petrol is dispensed to motor vehicle fuel tanks from
stationary underground storage tanks [1].

At terminals, petrol is stored in External Floating Roof Tank (EFRT) or in Internal Floating Roof Tanks
(IFRT).
Petrol transport is carried out by a combination of road, rail and water transport and by pipeline; this
last means releases no significant emissions.
At terminals, different means are used for loading of mobile containers (road tankers, rail tankers,
barges and marine tankers). Bottom loading and top loading of containers are used. VOC emissions
depend on the type of container being loaded, the degree of saturation of the vapour in the cargo tank
[2] and also how loading is carried out.
Petrol is delivered to service-stations where it is transferred into underground storage tanks and sub-
sequently dispensed into automobile fuel tanks. At service-stations, filling of underground tanks is
carried out via a fixed vertical pipe installed within the tank to which the road tanker is connected using
a hose. VOC emissions occur from the storage tank loading and breathing although the latter is
minimal as the tank is underground and hence not subject to diurnal changes in solar heating.
At service-stations, in addition to the emissions arising from fuel deliveries, there are emissions
released from the refuelling of vehicles.
Vehicle-refuelling operations are considered to be a major source of VOC emissions. These emissions
are attributable to vapour displaced from the automobile tank by dispensed petrol. The major factors
affecting the quantity of emissions are the volume of petrol dispensed, petrol temperature, vehicle tank
temperature, petrol vapour pressure, and dispensing rates. Especially, the vehicle tank temperature is
nowadays of major importance for refuelling emissions of modern gasoline injection cars. These VOC
emissions can be controlled by vapour balancing systems, so-called Stage II controls which have
been legislated for on a national basis in a large number of EU countries or by an enlarge d carbon
canister system which is mandated in the USA.

Emission control options from mobile tank filling and service-station storage tank filling are generally
named stage I controls. In the EU, these activities are regulated under the European Parliament and
Council Directive 94/63/EC of 20 December 1994 on the control of volatile organic compound
emissions resulting from the storage of petrol and its distribution from terminals to service stations [1].
Emission control options concerning car refuelling are generally termed stage II controls.
In the scope of air thematic strategy programme, the EU has issued a proposal of directive related to
stage II of petrol vapour recovery during refuelling of passenger cars [11]. BAT, associated emission
levels.

7.20.3.1 Petrol storage

BAT are described in chapter 7.5.
7.20.3.2 Stage I controls

Stage I controls mainly consist of vapour balance lines and vapour recovery units (VRU) to recover
petrol. Modified loading, e.g. bottom loading of road tankers, results in a smaller vapour loss than top
loading. Bottom loading enables reduced VOC emissions compared to top loading and importantly
permits more efficient vapour collection than with modified top loading arms.
Vapours collected at service stations from the discharge of petrol from road tankers can be returned
via the road tankers and recovered in the terminal VRU. The VRU unit is based on adsorption on
activated carbon, absorption, membrane separation or hybrid systems combining cooling/absorption
and compression/absorption/membrane separation [9]. The overall efficiency of VRU ranges from 95
to more than 99 % [9]. Stage I controls also mean modifications to road and rail tankers and to ships
and barges. In the latter cases, extra care must be taken to maintain safety standards particularly to
prevent propagation of ignition and over- or under-pressurisation of cargo tanks.
7.20.3.3 Stage II controls

VOC emissions from car refuelling can be controlled by vapour balancing systems, so-called stage II
controls, or by an enlargement of the on-board canister already installed on automobiles to capture
fuel system hot soak losses. Stage II controls are technically capable of achieving a 85-92% recovery
(depending on the capture efficiency). The costs of stage II are rather site-specific and vary widely.
To reduce VOC emissions from vehicle tank filling at service stations, active vapour recovery systems
can be used. They are based on the following principle: the petrol air vapour mixture escaping from
the tank during filling is sucked off at the vapour spout of the nozzle and vapours are returned back to
the storage tank. The air/vapour mixture has to be returned proportionally to the flow rate of petrol
delivered. Components of an open active petrol vapour recovery system include:
a vapour recovery nozzle,
a hose through which vapours are collected and a pipe through which the vapours are returned
to the underground tank
a vacuum pump and a system to control the ratio of the volume of vapour recovered to the
volume of petrol dispensed in the vehicle tank.
The ratio Vapour/Petrol (V/P) has to range from 95 % to 105/110 % vol. Greater V/P ratio cannot be
used to avoid excessive pressure built up and consequent VOC release through the pressure relief
valves of the storage tank.
The control of the ratio can be achieved by a proportional valve controlled either hydraulically or
electronically. Electronic regulation systems are the most widely used. However two systems can be
distinguished: the Electronic Controlled Vapour Recovery (ECVR) – open loop – without regulation
and the Electronic Controlled Vapour Recovery – Self Calibrating Gas – with regulation.
With active systems ECVR without regulation, VOC recovery efficiency cannot be maintained
effectively during the entire life time of the system. If maintenance and checks are not operated
carefully and periodically, efficiency decreases as the V/P ratio rapidly deviates from the optimal
values. A leak on the vapour line will reduce the volume of vapour returned and hence the recovery
efficiency.
With active systems ECVR with regulation, the control of vapour recovery is adjusted after each filling
operation. Each deviation from the optimum value is compensated electronically. The efficiency is
consequently stable during the life time of the system.
In both cases, theoretical VOC emission recovery efficiency is about 85 to 92 % wt. However in real
life, the efficiency of the ECVR with regulation is constant and consequently larger than the efficiency
of the ECVR without regulation. Faults can be detected and alarms can be installed to prevent
operations outside optimal values. If a fault is detected, the petrol delivery can be de-activated until the
fault is rectified [3]. This type of demand is presently implemented in some countries such as
Germany, Switzerland and UK.
Although experience with the first generation of Stage II systems was poor, the combination of routine
dry-tests (which electronically simulate the liquid flow and measure the air sucked in), regular visual

inspection by the service station personnel and the installation of a 'fault code' system (which check
that the equipment is working properly e.g. that the vapour pump is functional and that the vapour
control valves are operating within defined limits) can achieve consistently high recovery efficiencies at
approximately one tenth of the cost of the automatic monitoring system.
To achieve an overall VOC recovery efficiency of about 95 % wt, the V/P ratio has to be increased by
a factor 1.3 to 1.5 [4]. However, vapour recovery systems with V/P ratio larger than 100-110 % can
only be used if additional types of systems able to prevent any excessive pressure and consequent
VOC release through the pressure relief valves of the storage tank, are used. These systems are
based on membranes or compression and condensation [4], [6]. As example, the membrane unit is
installed in parallel to the vent stack of the petrol underground tank. The vapour sucked during car
refuelling is always returned to the storage by an active system. However the V/P ratio used is higher.
Consequently the surplus of vapours generates an over pressure in the storage tank. The pressure
gauge of the vacuum pump of the membrane unit controls the pressure. At a certain pressure, the
vacuum pump is activated and the tank pressure relieves over the membrane module to the
atmosphere. A global efficiency of 95% is obtained according to reference 4.
Other vapour recovery systems can be used, in which petrol vapours are recovered at the dispenser
and returned directly for sale. The equipment includes an active system to suck vapours with the
vacuum pump, a heat exchanger and a compressor which condenses the petrol vapours and a tank in
which water is separated from recovered petrol. The petrol recovered is conducted to the dispenser for
refilling a vehicle.
Table 1: associated emission levels with BAT to reduce VOC emissions in refinery petrol
dispatch station
emission levels*
3
kg VOC/m /kPa
[2], [9]
Road tanker filling, bottom or 0.0228 x 0.05 to
loading and VRU
Rail tanker, top loading and 0.0108 x 0.05 to
VRU VRU with 95 to 99 % efficiency [9] 0.0108 x 0.01
Marine tanker, typical cargo 0.004 x 0.05 to
tank condition 0.004 x 0.01
Barge – typical cargo tank 0.007x 0.05 to
conditions 0.007 x 0.01

Table 2: associated emission levels with BAT to reduce VOC emissions in intermediate petrol
storages
Intermediate depot
emission level
3
kg VOC /m /kPa*
[2], [9]
Petrol storage Internal floating roof Refer to the
External floating roof efficiency provided
Other tank designs and appropriate colours
97 to 99.5 % compared to a fixed roof tank
without measure [12]
Road tanker filling, bottom or VRU with 95 to 99 % efficiency [9] 0.0228 x 0.01 to
loading and VRU
Table 3: emission levels of available techniques to reduce VOC emissions from service-
stations
Service-stations
VOC source Available techniques Reduction Emission level
3
efficiency kg VOC /m /kPa
[2] and [6]
Underground Vapour return to the mobile Vapour return 0.0011
storage tank filling container (breathing losses not efficiency > 95 %
covered)
Car refuelling Well controlled and maintained Vapour recovery 0.0367 x 0.15
active systems with common efficiency > 85% w/w
vapour/petrol ratio of 95 to 105
% v/v
kPa is the true vapour pressure of the product delivered, m3 of petrol


Costs of stage I and stage II options are available for service-stations. Costs for service-stations
depend on the size of the station. Costs can be estimated as presented in the following table.
Investment costs for stage I come from the EGTEI data [5]. Investment costs for conventional ECVR
without regulation at the dispenser come from manufacturer data [7] and costs of works from
reference [8]. These costs have been determined for an ADEME study not yet published, made in
2007 by CITEPA [6].
Table 4: costs for stage I and stage II in service-stations of different sizes
Emissions Total Cost per

Avoided Invest- Operatio-
annual ton of
emissions ment nal cost
cost (10 VOC
years and abated
4%
interest €/t VOC
kg VOC/y kg VOC/y € €/an avoided
rate)€/an
No reduction 90
RI01
Stage I 59 32 6 400 789 24 955
< 100 m3 / an
Stage I and II 16 74 14 300 100 1 863 25 194
No reduction 588
RI02
Stage I 382 206 9 800 1 208 5 879
100 to 500 m3 / an
Stage I and II 107 481 22 600 200 2 986 6 213
No reduction 1 582 0
RI03
3 Stage I 1 028 553 12 600 1 553 2 807
500 to 1000 m / an
Stage I and II 288 1 294 30 200 400 4 123 3 186
No reduction 4 067
RI04
Stage I 2 645 1 423 15 200 1 874 1 317
1000 to 2000 m3 / an
Stage I and II 740 3 328 37 900 600 5 273 1 584
No reduction 5 197
RI05
Stage I 3 379 1 818 17 500 2 158 1 187
2000 to 3000 m3/an
Stage I and II 945 4 252 45 000 800 6 348 1 493
No reduction 7 909
RI06
Stage I 5 142 2 767 19 800 2 441 882
3000 to 4500 m3 / an
Stage I and II 1 438 6 471 52 100 1 000 7 423 1 147
No reduction 19 208
RI07
Stage I 12 488 6 719 27 000 3 329 495
> 4500 m3 / an
Stage I and II 3 493 15 714 79 000 2 000 11 740 747
For active systems, the cost efficiency ratio depends on the size of stations and decreases with the
3
decrease of the size. Costs range from 900 to 1 350 € / t VOC abated for stations larger than 3 000 m
3
per year, 1 700 – 1 800 € / t VOC abated for stations from 1 000 to 3 000 m per year and become
3
larger for smaller stations : 3 500 € / t VOC abated for stations from 500 to 1000 m per year, 6 500 € /
3
t VOC abated for stations from 100 to 500 m per year and 25 400 € / t VOC abated for stations
3
delivering less than 100 m per year.

[1] European Parliament and Council Directive 94/63/EC of 20 December 1994 on the control of
volatile organic compound (NMVOC) emissions resulting from the storage of petrol and its distribution
from terminals to service stations
[2] CONCAWE
Air pollutant emission estimation methods for E-PRTR reporting by refineries
Report n°1/2009 – 2009 edition
[3] VDI 4205 Part 5
Measurement and test methods for the assessment of vapour recovery systems on filling station
System test of automatic monitoring systems of active vapour recovery systems - September 2006
[4] Klaus Ohlrogge and Jim Wind
Membrane based vapour recovery at petrol stations - GKSS forchungszentrum
[5] EGTEI - Distribution of gasoline – Service stations - 2003
http://www.citepa.org/forums/egtei/egtei_doc-Fuel_distribution.htm
[6] NMVOC emissions from service stations – ADEME 2007- Not publicly available
VOC emissions from service stations – Synthesis – ADEME 2007 -
[7] TOKHEIM data provided to CITEPA – July 2006
[8] Data from Total - 2007
[9] European Commission - Reference document on best available techniques for mineral oil and gas
refineries - BREF – February 2003 – European commission – Available at: http://eipccb.jrc.es
[10] EPA - Emission factor documentation for AP42 section 7.1 - Organic liquid storage tanks
Final report - September 2006
[11] Proposal for a European Parliament and Council Directive on Stage II petrol vapour recovery
during refueling of passenger cars at service stations, {SEC(2008) 2937}, {SEC(2008) 2938}
4.12.2008, COM(2008) 812 final
[12] European Commission - reference document on BAT on emissions from storage – February 2003
– Available at: http://eipccb.jrc.es

7.21 Storage and handling of organic compounds (except petrol covered

by chapters 7.5 and 7.20)
7.21.1 Coverage
This chapter addresses the storage and handling of organic compound (vapour pressure higher than
10 Pa at 20°C) carried in activities such as the organic chemical industry, use of solvents, fine
chemical industry, etc. Petrol storage and handling is covered by chapters 7.5 and 7.20.

Storage and handling of liquid organic compounds (vapour pressure higher than 10 P a at 20°C) may
be source of VOC emissions.
7.21.3 BAT, Associated Emission Levels (AELs)

BAT description comes from reference 1 and 2.
Storage
Tank design
BAT for a proper design is to take into account at least as follows:
the physico-chemical properties of the substance being stored
how the storage is operated, what level of instrumentation is needed, how many operators are
required, and what their workload will be
how the operators are informed of deviations from normal process conditions (alarms)
how the storage is protected against deviations from normal process conditions (safety
instructions, interlock systems, pressure relief devices, leak detection and containment, etc.)
what equipment has to be installed, largely taking account of past experiences of the product
(construction materials, valve quality, etc.)
which maintenance and inspection plan needs to be implemented and how to ease the
maintenance and inspection work (access, layout, etc.)
how to deal with emergency situations (distances to other tanks, facilities and to the boundary,
fire protection, access for emergency services such as the fire brigade, etc.).
Inspection and maintenance
BAT is to apply a tool to determine proactive maintenance plans and to develop risk -based inspection
plans such as the risk and reliability based maintenance approach.
Inspection work can be divided into routine inspections, in-service external inspections and outof-
service internal inspections.
Tank colour
BAT is to apply either a tank colour with a reflectivity of thermal or light radiation of at least 70 %, or a
solar shield on aboveground tanks which contain volatile substances.
Emissions minimization principle in tank storage
BAT is to abate emissions from tank storage, transfer and handling.
External floating roof tank

The BAT associated emission reduction level for a large tank is at least 97 % (compared to a fixed
roof tank without measures), which can be achieved when over at least 95 % of the circumference the
gap between the roof and the wall is less than 3.2 mm and the seals are liquid mounted, mechanical

shoe seals. By installing liquid mounted primary seals and rim mounted secondary seals, a reduction
in air emissions of up to 99.5 % (compared to a fixed roof tank without measures) can be achieved.
However, the choice of seal is related to reliability, e.g. shoe seals are preferred for longevity and,
therefore, for high turnovers.
BAT is to apply direct contact floating roofs (double-deck), however, existing non-contact floating roofs
(pontoon) are also BAT.
Additional measures to reduce emissions are:
applying a float in the slotted guide pole
applying a sleeve over the slotted guide pole, and/or
applying ‘socks’ over the roof legs.
Fixed roof tanks

Fixed roof tanks are used for the storage of flammable and other liquids, such as oil products and
chemicals with all levels of toxicity.
For the storage of volatile substances which are toxic (T), very toxic (T+), or carcinogenic, mutagenic
and reproductive toxic (CMR) categories 1 and 2 in a fixed roof tank, BAT is to apply a vapour
treatment installation.
For other substances, BAT is to apply a vapour treatment installation, or to install an internal floating
roof.
The selection of the vapour treatment technology is based on criteria such as cost, toxicity of the
product, abatement efficiency, quantities of rest-emissions and possibilities for product or energy
recovery, and has to be decided case-by-case. The BAT associated emission reduction is at least 98
% (compared to a fixed roof tank without measures).
The achievable emission reduction for a large tank using an internal floating roof is at least 97 %
(compared to a fixed roof tank without measures), which can be achieved when over at least 95 % of
the circumference of the gap between the roof and wall is less than 3.2 mm and the seals are liquid
mounted, mechanical shoe seals. By applying liquid mounted primary seals and rim mounted
secondary seals, even higher emission reductions can be achieved. However, the smaller the tank
and the smaller the number of turnovers, the less effective the floating roof is.
Transfer and handling
Inspection and maintenance

BAT is to apply a tool to determine proactive maintenance plans and to develop risk -based inspection
plans such as, the risk and reliability based maintenance approach;
Leak detection and repair programme

For large storage facilities, according to the properties of the products stored, BAT is to apply a leak
detection and repair programme. Focus needs to be on those situations most likely t o cause
emissions (such as gas/light liquid, under high pressure and/or temperature duties).
Emissions minimisation principle in tank storage

BAT is to abate emissions from tank storage, transfer and handling that have a significant negative
environmental effect, This is applicable to large storage facilities, allowing a certain time frame for
implementation.
Operational procedures and training
BAT is to implement and follow adequate organisational measures and to enable the training and
instruction of employees for safe and responsible operation of the installation

Piping
BAT is to apply aboveground closed piping in new situations. For existing underground piping it is BAT
to apply a risk and reliability based maintenance approach.
Bolted flanges and gasket-sealed joints are an important source of fugitive emissions. BAT is to
minimise the number of flanges by replacing them with welded connections, within the limitation of
operational requirements for equipment maintenance or transfer system flexibilit y,
BAT for bolted flange connections include:

• fitting blind flanges to infrequently used fittings to prevent accidental opening
• using end caps or plugs on open-ended lines and not valves
• ensuring gaskets are selected appropriate to the process application
• ensuring the gasket is installed correctly
• ensuring the flange joint is assembled and loaded correctly
• where toxic, carcinogenic or other hazardous substances are transferred, fitting high integrity
gaskets, such as spiral wound, kammprofile or ring joints.
Internal corrosion may be caused by the corrosive nature of the product being transferred, BAT is to
prevent corrosion by:
• selecting construction material that is resistant to the product
• applying proper construction methods
• applying preventive maintenance, and
• where applicable, applying an internal coating or adding corrosion inhibitors.
To prevent the piping from external corrosion, BAT is to apply a one, two, or three layer coating
system depending on the site-specific conditions (e.g. close to sea). Coating is normally not applied to
plastic or stainless steel pipelines.
Vapour treatment
BAT is to apply vapour balancing or treatment on significant emissions from the loading and unloading
of volatile substances to (or from) trucks, barges and ships. The significance of the emission depends
on the substance and the volume that is emitted, and has to be decided on a case-by-case basis.
Valves
BAT for valves include:
• correct selection of the packing material and construction for the process application
• with monitoring, focus on those valves most at risk (such as rising stem control valves in
continual operation)
• applying rotating control valves or variable speed pumps instead of rising stem control valves
• where toxic, carcinogenic or other hazardous substances are involved, fit diaphragm, bellows,
or double walled valves
• route relief valves back into the transfer or storage system or to a vapour treatment system.
Pumps and compressors

Installation and maintenance of pumps and compressors
The design, installation and operation of the pump or compressor heavily influence the life potential
and reliability of the sealing system. The following are some of the main factors which constitute BAT:

• proper fixing of the pump or compressor unit to its base-plate or frame

• having connecting pipe forces within producers’ recommendations
• proper design of suction pipework to minimise hydraulic imbalance
• alignment of shaft and casing within producers’ recommendations
• alignment of driver/pump or compressor coupling within producers’ recommendations when
fitted
• correct level of balance of rotating parts
• effective priming of pumps and compressors prior to start-up operation of the pump and
compressor within producers’ recommended performance range (The optimum performance is
achieved at its best efficiency point.)
• the level of net positive suction head available should always be in excess of the pump or
compressor
• regular monitoring and maintenance of both rotating equipment and seal systems, combined
with a repair or replacement programme.
Sealing system in pumps

BAT is to use the correct selection of pump and seal types for the process application, preferably
pumps that are technologically designed to be tight such as canned motor pumps, magnetically
coupled pumps, pumps with multiple mechanical seals and a quench or buffer system, pumps with
multiple mechanical seals and seals dry to the atmosphere, diaphragm pumps or bellow pumps.
Sealing systems in compressors
BAT for compressors transferring non-toxic gases is to apply gas lubricated mechanical seals. BAT for
compressors, transferring toxic gases is to apply double seals with a liquid or gas barrier and to purge
the process side of the containment seal with an inert buffer gas. In very high pressure services, BAT
is to apply a triple tandem seal system.
Table 1: associated Emission Levels with BAT to reduce VOC emissions from storage of
organic compounds
Emission sources Combination of BAT BAT Associated Emissions

Levels for VOCs
Internal floating roof
Storage tanks of volatile External floating roof 97 to 99.5 % compared to a
products fixed roof tank without
Other tank designs and appropriate
measure*
colours
* If the efficiency cannot be reached because of the specific characteristics of a storage tank (such as small
throughput, small diameter), best available primary and secondary seals have to used.
7.21.4 Cost data for emissions reduction techniques

.No cost data are available.

[1] European Commission - reference document on BAT in emissions from storage - July 2006.
[2] European Commission - reference document on BAT on emissions from storage – February 2003
– Available at: http://eipccb.jrc.es

Mis en forme
7.22 Manufacture of organic chemicals (Except production of organic
fine chemicals, chapter 7.23)
7.22.1 Coverage
In this chapter, the organic chemical industry is the industry aiming at producing the following types of
products :
lower olefins such as ethylene and propylene produced mainly by the steam cracking route,
aromatics compounds such as benzene and toluene,
oxygenated compounds,
nitrogened compounds,
halogenated compounds,
polymers (polyethylene, polypropylene, PVC, polyesters, polystyrene...).

In the production of organic chemicals, emissions differ widely according to the products and
production processes. Often one product is produced by different processes, each of which has its
own emission characteristics with regard to VOCs.
VOCs emissions arise from some main sources, as follows:
fugitive emissions. Fugitive VOC emissions are released from leaking pressurised equipment
components on process units, such as valves, flanges and connectors, opened lines and
sampling systems containing volatile liquids or gases. Volatile products are defined in CEN
15446 [7] and reference [8] as all products of which at least 20% by weight has a vapour
pressure higher than 0,3 kPa at 20°C,
stack emissions,
flaring systems (used for safe disposal of hydrocarbons or hydrogen that cannot be recovered in
the process),
storage and handling of chemical substances treated in chapter 7.21.

New installations:
When new processes are designed and in case of major modification of existing processes, BAT is a
selection of the following techniques:
carry out chemical reactions and separation processes continuously, in closed equipment,
subject continuous purge streams from process vessels to the hierarchy of: re-use, recovery,
combustion in air pollution control equipment and combustion in non dedicated equipment
minimise energy use and maximise energy recovery,
use compounds with low or lower vapour pressure.
Process modification, including changes of feedstock and products, can in selected cases help to
reduce VOC emissions. New chemical reactions or principles may be applied to reduce the quantity of
undesired by-products. Process improvements must also aim at recovery and recycling of by-products
as well as at enclosing open process equipment as far as possible.

An efficient measure to reduce waste gas flow rates and VOC emissions from oxidation and
oxychlorination processes (e.g. production of vinyl chloride) is the use of pure oxygen instead of air.
New oxidation and oxychlorination plant usually uses only pure oxygen.
Fugitive VOC emissions:

For preventing and controlling fugitive VOC emissions, BATs are a combination of leak detection and
repair programme as and the use high performance equipment:
Mis en forme : Retrait : Gauche : 1
Aa leak detection and repair programme (LDAR) consisting consists in measuring the cm, Sans numérotation ni puces
concentration of VOC in the atmosphere around the potential leak, then selecting equipments
leaking over a defined threshold value and finally operating a repair on those leaking items.
A LDAR programme is established according to the following principles [6]:
- the definition of what constitutes a leak and fixation of corresponding thresholds,
- the fixation of the frequency of inspections,
- the listing and identification of components included,
- the procedures concerning repair of leaking components depending of the leak category.
Immediate minors repair can be carried out immediately such as tightening leaking equipment.
Maintenance and complex repair have to be scheduled. They can be done during scheduled
shutdown.
Equipment tightening can be made with equipment in operation (except with remote control valves (eg
tightening bolts to eliminate leaks from valves stems or flanges, installing tightening caps on open
ends…). ,etc).
Maintenance with dismantling equipment or exchange, can only be carried out during plant shutdowns
with circuit insulation and degassing. So, during plant shutdowns, two kinds of maintenance
programme can be carried out according to the situation [6]:
- basic maintenance: maintenance on the equipment (flanges + valves) to remove some parts or
to change the equipment with a new one of the same technology.
- heavy maintenance: complete change of the valves with valves of the higher grade standard,
not leaking technology. Basic maintenance is maintained for the flanges.

use Hhigh- performance equipment such as consists of the following [1]: cm, Sans numérotation ni puces
- valves: low leak rate valves with double packing seals, bellow seals for high risk duty,
- pumps: double seals with liquid or gas barrier, or seal pumps,
- compressors and vacuum pumps: double seals with liquid or gas barrier, or seal less pumps, or
simple seal technology with equivalent emission levels,
- flanges: minimise the number, use effective gaskets,
- open ends: fir blind flanges, caps and plugs to infrequently used fittings, use closed loop flush
on liquid sampling points, and for sampling systems analysers optimise the sampling
volume/frequency, minimise the length of sampling lines or fit enclosures,
- safety valves: fit upstream rupture disk.
Stack VOC emissions:

VOC in vent gases can be controlled by conventional methods of controlling organic pollutants from
stationary sources, i.e. adsorption, absorption, condensation, membrane process, thermal and
catalytic incineration, as well as process modification. These techniques are presented in chapter
5.3.2.

Flare emissions:
for preventing flare emissions, BAT is:
- minimise the need for hydrocarbon disposal to flare through good plant design and good plant
management
- BAT for elevated flare design and operation includes the provision of permanent pilots and
pilots flame detection, efficient mixing, ratio controlled to the hydrocarbon flow and remote
monitoring by closed circuit television
- destruction efficiency larger than 99% for elevated flare and 99.5 % for ground flares.
VOC from storage, handling and transfer [1] and [2]:

BAT for storage, handling and transfer is, in addition to those described in chapter 7.2221, an
appropriate combination or selection of, inter alia, the following techniques:
external floating roof with secondary seals (not for highly dangerous substances), fixed roof ;
tanks with internal floating covers and rim seals (for more volatile liquids), fixed roof tanks ;
with inert gas blanket, pressurised storage (for highly dangerous or odorous substances);
inter-connect storage vessels and mobile containers with balance lines;
minimise the storage temperature;
instrumentation and procedures to prevent overfilling;
impermeable secondary containment with a capacity of 110 % of the largest tank;
recover VOCs from vents (by condensation, absorption or adsorption) before recycling or
destruction by combustion in an energy raising unit, incinerator or flare; cm, Sans numérotation ni puces
continuous monitoring of liquid level and changes in liquid level;
tank filling pipes that extend beneath the liquid surface;
bottom loading to avoid splashing;
sensing devices on loading arms to detect undue movement;
self-sealing hose connections / dry break coupling.

Unit costs range from -100 to + 180 €/t VOC abated according to the reduction measure considered
according to EGTEI [9] for implementing a LDAR programme to reduce fugitive emissions for the
steam cracking unit. Negative costs indicate that savings are high and counter balance.
Unit costs range can be much larger and range as example from 310 to 1050 €/t VOC abated
according to the reduction measure considered in the production of PVC [10].

[1] European Commission - Reference document on BAT in the large volume organic chemical
industry – February 2003
[2] European Commission - Reference document on BAT in the production of polymers – 2006
[3] European Commission - Reference document on BAT for the manufacture of organic fine
chemicals August 2006
[4] European Commission - reference document on BAT in common waste water and waste gas
treatment / management systems in the chemical sector – February 2003.

[5] European Commission - reference document on BAT in on emissions from storage to be

completed – February 2003July 2006.
[6] EGTEI background document on the organic chemical industry.
[7] EN15446:2008 Fugitive and diffuse emissions of common concern to industry sectors -
Measurement of fugitive emission of vapours generating from equipment and piping leaks
[8] EPA - Protocol for equipment leak - Emission estimates EPA 453-95-017 – 1995
[9] EGTEI - Organic chemical industry – steam cracking – synopsis sheet - 15 October 2005
http://www.citepa.org/forums/egtei/10-Synopsis-sheet-steam-cracking-15-10-05.pdf
[10] EGTEI - Organic chemical industry – Production of PVC – synopsis sheet - 3 October 2005
http://www.citepa.org/forums/egtei/11-synopsis-sheet-PVC-suspension-03-10-05.pdf

and black carbon) from stationary sources Mis en forme : Police :9 pt
7.23 Production of organic fine chemicals

7.23.1 Coverage
The speciality organic chemical industry covers the production of different types of chemicals
produced in campaign basis, in multi purpose and multi product plants (pharmaceutical active
ingredients, biological products, food additives, photographic chemicals, dyestuffs and intermediates,
pesticides and other speciality products…) [1].
The pharmaceutical product manufacturing is part of the organic chemical industry and covers both:
the production of primary pharmaceutical products: production of bulk pharmaceuticals, drug
intermediates and active ingredients by means of synthesis, fermentation, extraction or other
processes, in multipurpose and multi product plants and on a campaign basis.
the activities related to formulation of finished drugs and medicines using the active ingredients
supplied by the bulk plants (taking place in finishing plants). Active ingredients are converted
into products suitable for administration. Physical formulation, filling and packaging are
involved.
Only VOC emissions are covered in this chapter.

This industry is very heterogeneous: plants manufacture a large range of products, using a large
number of production processes and may store and use several hundred raw material substances or
intermediate products. Processes are usually operated on a campaign basis and in multi purpose
plants. For one active ingredient, several transformation stages are required. The processes typically
involve between 1 to 40 transformation stages depending on molecules. Process stages cover the full
range of unit operations such as: reactions, liquid/liquid extraction, liquid/liquid or liquid/solid or
gas/solid separation, distillation, crystallisation, drying, gas adsorption… etc. Production is carried out
in discontinuous processes (or batch processes). Equipment is rarely specific but, most often, multi
application. Processes frequently use solvents. Any reacted raw materials may be either recovered or
recycled or ultimately discharged to the environment after appropriate treatment.
Due to the diversity of processes used in this sector, no simple process description can be made.
Instead, a brief outline of characteristics of existing pharmaceutical product production plants is
provided.
Significant number of VOC emission release points

Gaseous discharge circuits are complex. For the same equipment, several discharge points often
exist, depending on the performed operations. The large number of discharge points is due to:
quality constraints required in this sector in order to avoid risks of cross-contamination,
security constraints in order, for example, to avoid the contact of incompatible gases.
Plants having an annual solvent consumption ranging from 900 to 1 500 t may have from 10 to 50
VOC emission vent stacks in the atmosphere.
A large number of discharge points are equipped with condensers to trap VOCs. To trap corrosive or
toxic gases, several vents are related to abatement absorption columns. W hen secondary abatement
techniques are applied, collecting the vents proves to be necessary.
High variability of VOC discharges with time

VOC concentrations may vary widely from one discharge point to another. Discharges with high waste
gas flow rates and low concentrations do exist; general ventilation of a factory belongs to this group.
Other discharges, such as production equipment vents are characterised by very low waste gas flow
3
rates (some Nm /h) and VOC concentrations that may be high.

VOC discharges present a very high variability over time: high variability over time when there is a
discharge and non-permanent discharges.
This situation leads to more significant costs for emission treatment: the gas-cleaning device should
be able to accept emission peaks. Abatement technique dimensioning must be based on the peak
discharge (the frequency of peaks should be considered as well). Investments are thus higher than for
more regular emissions in time.
A large number of solvents used

In this activity, even though 5 solvents (methanol, toluene, acetone, ethanol, methane dichloride)
represent about 70 % of the new solvent consumption [1], around 40 different solvents are in use. The
consumption of chlorinated solvents is still quite high. This large number of solvents, the presence of
chlorinated solvents and security and quality constraints make the use of secondary abatement
techniques more difficult and more expensive (treatment of HCl if incineration, limited potential for
collection and recycling of solvents).

In order to reduce solvent losses and emissions into the atmosphere, a wide range of best practices
and process improvements are available among which work in concentrated environment in order to
reduce the consumption of solvents, increased use of low volatile solvents and of solvents easier to
condense, modification of certain operating conditions for distillation (e. g. distillation under ordinary
pressure instead of vacuum distillation), implementation of good housekeeping, increased condenser
efficiency (increased exchanger surfaces and increased refrigerating capacities), technology change
(dry-sealed vacuum pumps instead of liquid ring vacuum pumps; closed pressure filters or vacuum
filters more leak free than open filters; vacuum dryers leading to a better solvent condensation…).,
etc).
A list of BAT is a follows [2]:
contain and enclose sources and close any openings in order to minimise uncontrolled
emissions,
carry out drying using closed circuits, including condensers for solvent recovery,
keep equipment closed for rinsing and cleaning with solvents,
close unnecessary openings in order to prevent air being sucked to the gas collection system
via the process equipment,
ensure the air tightness of process equipment, especially of vessels,
apply shock inertisation instead of continuous inertisation,
minimise the exhaust gas volume from distillations by optimisation of the layout of the
condenser,
carry out liquid addition into vessels as bottom feed or with dip leg, unless reaction chemistry
and / or safety considerations make it impractical. In such cases, the addition of liquid as top
feed with a pipe directed to the wall reduces splashing and hence the organic load of the
displaced gas,
minimise the accumulation of peak loads and flows and related concentration peaks by
optimisation of the production matrix and application of smoothing filters.
treatment of waste gases containing VOC. The selection of VOC treatment techniques is a
crucial task on a multipurpose site. Since the volume flows show a wide variation on a
multipurpose site, the key parameter for the selection of techniques are average mass flows
from emission point sources in kg/hour. One or a combination of techniques can be applied as a
recovery/abatement system for a whole site, an individual production building, or an individual
process. This depends on the particular situation and affects the number of point sources. Non-
oxidative recovery/abatement techniques are operated efficiently after minimisation of volume
flows and the achieved concentration levels should be related to the corresponding volume flow

without dilution by, e.g. volume flows from building or room ventilation. Thermal
oxidation/incineration and catalytic oxidation are proven techniques for destroying VOCs with
highest efficiency but show considerable cross-media effects. In direct comparison, Catalytic
oxidation consumes less energy and creates less NOx and hence is preferred where technically
possible. Thermal oxidation is advantageous where support fuel can be replaced by organic
liquid waste (e.g. waste solvents which are technically/economically available on-site and non-
recoverable) or where autothermal operation can be enabled by stripping of organic compounds
from waste water streams. Where exhaust gases also contain high loads of other pollutants
besides VOCs, thermal oxidation can enable, e.g. the recovery of marketable HCl or, if the
thermal oxidiser is equipped with a DeNOx unit or is designed as two stage combustion, the
efficient abatement of NOx.Thermal oxidation/incineration and catalytic oxidation can also be a
suitable technique to reduce odour emissions.
BAT is to reduce emissions to the levels given

Existing installations can reduce their total VOC emissions to less than 5 % of the solvent input by
following a combined strategy which involves:
a) Step-by-step implementation of integrated measures to prevent/reduce diffuse/fugitive emissions
and to minimise the mass flow that requires abatement
b) Applying high level recovery/abatement techniques, such as thermal/catalytic oxidation or activated
carbon adsorption
c) Applying specific recovery/abatement techniques at source on smaller sites with dedicated
equipment, and by utilising only one or two different bulk solvents.
Table 1: selected VOC control measures with BAT associated VOC emission levels for organic
fine chemicals
Emission source Combination of control measures BAT associated
emission levels for VOC
New plants Mix of BAT defined above (primary measures ≤ 3 % of solvent input*
and use of secondary measures (both oxidation,
adsorption and / or condensation))
Existing plants Mix of BAT defined above (primary measures ≤ 5% of solvent input*
and use of secondary measures (both oxidation,
adsorption and / or condensation))
* Sum of I1 the quantity of organic solvents or their quantity in preparations purchased which are used as input into the process
in the time frame over which the mass balance is being calculated + I2 the quantity of organic solvents or their quantity in
preparations recovered and reused as solvent input into the process. (The recycled solvent is counted every time it is used to
carry out the activity.)
Table 2: BAT Associated VOC Emission Levels for non-oxidative recovery/abatement

techniques [2]
Process step Average emission level from point sources*
Non-oxidative recovery/abatement techniques 0.1 kg C/hour* or 20 mg C/m3**
*The averaging time relates to the emission profile, the levels relate to dry gas and Nm3
**The concentration level relates to volume flows without dilution by, e.g. volume flows from room or
building ventilation

Table 3: BAT associated emission levels for total organic C for thermal oxidation/incineration
or catalytic oxidation [2]
Process step Average emission level from point sources*
Thermal oxidation/incineration Average mass flow or Average
or catalytic oxidation < 0.05 kg C/h** concentration**
3
< 5 mg C/m
3
* The averaging time relates to the emission profile, levels relate to dry gas and Nm
**
These values are technically demanding and attention has to be carried out on energy efficiency
which might be not acceptable
7.23.4 Cost data for emission reduction technique
Costs vary in a large range. Average investments to achieve best performance levels on an existing
plant are about 6700 k€ and the total costs per kg of abated VOC of 2.3 €/kg [8].
7.23.5 Reference used for chapter 7.23
[1] Speciality organic chemical industry. EGTEI background document – 24 may 2005
http://www.citepa.org/forums/egtei/speciality_chemistry_290405.pdf
[2] European commission - reference document on BAT for the manufacture of organic fine chemicals
August 2006
[3] Council Directive 1999/13/EC of 11 March 1999 on the limitation of emissions of volatile organic
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31999L0013:EN:HTML
[4] Regulation (EC) No 166/2006 of the European Parliament and of the Council of 18 January 2006
concerning the establishment of a European Pollutant Release and Transfer Register and amending
Council Directives 91/689/EEC and 96/61/EC
[5] Arrêté du 31 janvier 2008 relatif au registre et à la déclaration annuelle des émissions polluantes et
des déchets - (JO n° 62 du 13 mars 2008)
[6] Comments from André Peeters Weem, Cees Braams from InfoMil, the Dutch Ministry of
Environment on GD 7-26 Manufacture of organic fine chemical - version 1
[7] Comments from Johannes Drotleff, German Umweltbundesamt on GD 7-26 Manufacture of organic
fine chemical - version 1
[8] Speciality organic chemical industry. Synopsis sheet – 3 October 2005
http://www.citepa.org/forums/egtei/31-Synopsis-sheet-Speciality-organic-chemical-industry-03-10-
05.pdf

Mis en forme
7.24 Adhesive coating (including footwear manufacture)
7.24.1 Coverage
Sectors using adhesives are very diverse. Production processes and application techniques are also
very different. Relevant sectors are: the production of adhesive tapes, composite foils, the
transportation sector (passenger cars, commercial vehicles, mobile homes, rail vehicles, aircrafts), the
manufacture of shoes and leather goods and the wood material and furniture industry. The non-
industrial use of adhesives is a large sector but it is studied separately.

Application techniques and types of adhesives used differ widely from one sector to another.
Adhesives can be applied manually, by spraying, or roller coating. The application efficiency depends
on the type of technique used. Solvent contents in the adhesives depend highly on the type of material
consumed. Solvent content in solvent-based adhesives can be as high as 80%. Dispersion glues
contain some 2 - 6 % solvents; and melting glues are solvent-free. Each type of adhesive has different
physical and chemical properties.

BAT AEL and techniques are based on STS BREF [1] for the manufacture of adhesive tapes and on
EGTEI data [2] for the other sectors.
Reduction techniques are general but are suitable among sectors using adhesives.
Solvent-based adhesive coating processes generate significant amounts of VOC emissions, which
can be reduced either by primary measures (substitution by zero or low organic solvent containing
adhesives) or by secondary measures for larger installations (adsorption, thermal or catalytic
oxidation). A selection of such measures applied to selected base processes is given in table 1.
Table 1: Emission sources and selected VOC control measures with associated emission
levels for adhesive coating and shoe manufacturing
Type of installation Combination of control Associated emission levels
measures for VOC
[Defined for the following
averaging period: (yearly
average for total AEL])
Manufacturing of adhesive tape Use of condensation, adsorption, Total emission of 5 wt-% or
oxidation or a combination of less of the solvent input [1]
these techniques
Manufacturing of adhesive tape Use of non-solvent based 0 g/kg adhesive
Adhesive coating in other sectors adhesives [2]
Use of condensation, adsorption, < 150 g/kg adhesive [5]
oxidation or a combination of
these techniques
Use of water-based adhesives 20 g/kg adhesive [2]
Shoe industry Use of water-based adhesives 20 – 30 g / pair [3]
Use of biofiltration


Costs vary between about 0.1 and 0.7 k€/t VOC abated according to the type of measure applied (i.e.
treatment or solvent consumption reduction): abatement costs are even less expensive with 100%
solid content adhesives compared to solvent-based products but these systems are not always
technically applicable. These costs are representative for large installations.
For the particular sector of shoe manufacturing, the implementation of thermal oxidation will lead to
abatement costs around 8 to 11 k€/t VOC and the use of water-based products around 0.7 k€/t VOC
but this last technique does not seem to be applicable to all types of productions.
The detailed methodologies used to estimate these costs are defined in EGTEI documents concerning
“adhesive application“ [2] and “manufacture of shoes” [3].
Caution: these documents are susceptible to evolve if new updated data are available.

No data is available.

[1] STS BREF – August 2007
[2] EGTEI background document/synopsis sheet: Adhesive application – 2003/2005
[3] EGTEI background document/synopsis sheet: Manufacture of shoes – 2003/2005
[4] Directive 1999/13/EC of 11 March 1999 on the limitation of emissions of volatile organic
[5] Comments from Birgit Mahrwald – UBA

Mis en forme
7.25 Coating processes 1: coating of cars, truck cabins, trucks and
buses
7.25.1 Coverage
This sector covers the coating of passenger cars, truck cabins, trucks and buses.

Major steps of such processes may include:
preliminary cleaning, phosphating, electrophoretic coating (also called electrocoating or
electrodeposition);
application of primer, curing of primer;
application of topcoat(s), curing of topcoat(s);
under body sealing and sealing of seams, cavity corrosion protection, and repair painting before
assembly.

BAT AELs are based on STS BREF [1]. Combinations of control measures are derived from
discussion with ACEA [2] and correspond to the BAT.
Table 1: emission sources and selected VOC control measures with associated emission levels
for coating processes
Type of installation Combination of control measures BAT associated emission levels
[4] for VOC
averaging period:( yearly average
for total AEL)]
Manufacture of cars Electrocoat: water-based (5 wt.-% 10 – 35 g VOC/m² or 0.3 kg/body +
(M1, M2) solvent content) 8 g/m² to 1 kg/body + 26 g/m²
Primer: water-based (8 wt.-%
solvent content) - electrostatic
application
Topcoat :
- High solid coat (45 wt.-%
solvent content) - electrostatic
application, and
- water-based basecoat (15 wt.-
% solvent content) –
electrostatic application – and
solvent-based clear coat (45 –
55 wt.-% solvent content) -
electrostatic application
Solvent management plan, recovery
of purge solvent
Manufacture of truck WB enamels 10 – 55 g VOC/m²
cabins (N1, N2, N3) HS clearcoat
Improved solvent recovery / solvent
consumption reduction
Oxidation on ovens

Manufacture of trucks WB primer and topcoat for high 15 – 50 g VOC/m²

(N1, N2, N3) runners and HS topcoat for special
orders
Manufacture of buses Cataphoresis 92 – 150 g VOC/m²
(M3) WB enamels
HS clearcoat
Oxidation on cataphoresis, mid-
layer and enamel ovens
Manufacture of vans WB enamels 15 – 50 g VOC/m²
HS clearcoat
Oxidation on ovens
The surface area is defined as the total electrophoretic coating area, and the surface area of any parts
that might be added in successive phases of the coating process which are coated with the same
coatings as those used for the product in question, or the total surface of the total product coated in
the installations.
M1: vehicles used for the carriage of passengers and comprising not more than eight seats in addition
to the driver's seat.
M2: vehicles used for the carriage of passengers and comprising more than eight seats in addition to
the driver's seat, and having a maximum mass not exceeding 5 Mg.
M3: vehicles used for the carriage of passengers and comprising more than eight seats in addition to
the driver's seat, and having a maximum mass exceeding 5 Mg.
N1: vehicles used for the carriage of goods and having a maximum mass not exceeding 3.5 Mg.
N2: vehicles used for the carriage of goods and having a maximum mass exceeding 3.5 Mg but not
exceeding 12 Mg.
N3: vehicles used for the carriage of goods and having a maximum mass exceeding 12 Mg.

Costs are defined in the EGTEI documents “car coating“ [3], truck and van coating [4], truck cabin
coating [5] and bus coating [6].
For the manufacture of cars, abatement costs corresponding to BAT vary from 11 to 25 k€/tonne of
VOC abated. Some techniques have even higher costs.
For the manufacture of trucks and vans, abatement costs vary between 12 k€/t VOC and 22 k€/t VOC
abated depending on the associated emission level reached (i.e. Solvent Directive requirem ents or
BAT).
For the manufacture of trucks cabins, abatement costs vary between 21 k€/t VOC and 33 k€/t VOC
abated depending on the associated emission level reached (i.e. Solvent Directive requirements or
BAT).
For the manufacture of busses, abatement costs vary between 13 k€/t VOC and 23 k€/t VOC abated
depending on the associated emission level reached (i.e. Solvent Directive requirements or BAT).
The detailed methodologies used to estimate these costs are defined in EGTEI documents concerning
“car coating“ [3], “truck coating” [4], “truck cabin coating” [5] and “bus coating” [6].


No quantitative data is available.

[2] Internal meeting ACEA / EGTEI – July 2006
[3] EGTEI background document/synopsis sheet: Car coating – 2003/2005
[4] EGTEI background document/synopsis sheet: Truck coating – 2003/2005
[5] EGTEI background document/synopsis sheet: Truck cabin coating – 2003/2005
[6] EGTEI background document/synopsis sheet: Bus coating – 2003/2005


Mis en forme
7.26 Coating processes 2: Winding wire coating
7.26.1 Coverage
Only the coating of metallic conductors used for winding the coils in transformers, motors, etc. is
considered in this section.

Wires are coated by passing continuously through a bath of enamel. Coated wires are then dried in a
heated chamber where solvents are evaporated and the film is cured a t a hirehigh temperature. Up to
30 applications of enamel may be applied until the desired layer thickness is obtained. Recirculated
airflow ovens are in use in contemporary wire coating processes. The air/solvent mix is usually treated
in a catalytic oxidiser which ensures that residual solvent concentrations are below legal threshold
3
limits (typically 20 – 30 mg C/Nm ). The heat from the thermal oxidiser can be used in the drying
process [1].
Depending on the final product requirements, a film of wax may be applied to the surface of the
enamelled wire before it is wound on to a delivery reel. Traditionally, typical paraffin is applied from an
organic solvent with a solvent content from 98 to 99.9%. Lubricants, as concentrated emulsions, with a
solvent content between 50 to 95%, water-based emulsions or even solvent-free hot melts are also
used in this industry, though with limited success [1].
There are now two methods available for applying solid wax to the wire surface. One method uses
wax coated string in contact with the surface and the other is by applying a molten wax to the surface
of the wire.

Abatement options based on the STS BREF [1] are defined in the table 1 bellow.
for winding wire coating
BAT associated
emission levels for
VOC
[Defined for the
Emission source Combination of control measures
following averaging
period: (yearly
average for total
AEL])
All plants Use of low solvent-based materials (such as 5 g/kg wire or less for
high solids enamel coatings and solvent-free non-fine wires (> 0.1
lubricants) and/or processes mm diameter)
And
Use of catalytic oxidiser to treat emissions 10 g/kg wire or less
from the enamel coating step for fine wires (0.01 -
0.1 mm diameter)

Costs are defined in the EGTEI documents concerning “wire coating“ [2]. Abatement costs (€/tonne of
VOC abated) are considered to be negative as when an oven is replaced, the only choice is to buy a
more efficient one leading to energy savings.


Waxing of fine wires: this technique is considered the solvent emissions from the final drying of wax on
fine wires (0.01 – 0.1 mm) [1].

[2] EGTEI background document/synopsis sheet: Wire coating – 2003/2005

Mis en forme
7.27 Coating processes 3: Coil coating
7.27.1 Coverage
Coil coating (of metal coil surface) is a linear process by which protective and/or decorative organic
coatings are applied to flat metal sheets or strips packaged in rolls or coils.

The metal strip is sent through a coating application station, where rollers coat one or both sides of the
metal strip. Roller coaters assure a very high transfer efficiency of the paint on the strip. The strip then
passes through an oven where the coatings are dried and cured. As the strip exits the oven, it is
cooled by water spray and/or air quenching and again dried. If the line is a tandem line, as most are,
there is first the application of a primer, followed by another of topcoat on one or both sides of the
strip.
Solvent-based paints containing between 40 and 50% of solvent are commonly used. There is no
technical limit for the use of solvent-based paints.
7.27.3 BAT, Associated Emissions Levels (AEL)

The potential of use of the different coatings is different. Water-based paints almost disappeared in the
early 80s and have not seen significant usage since due to technical difficulties in manufacture and
limitations in use. The use of powder coatings is limited as their application is still technologically and
economically difficult. For the time being, powder line speed is about 10 m/min vs. 50 - 100 m/min for
most liquid paint lines, while film thicknesses less than 60 m are difficult and expensive to achieve in
powder. These factors combined make powder uncompetitive against traditional solvent-based coil
coatings in most applications.
BAT AELs are based on the STS BREF [1] and on information from ECCA [4].They are presented in
table 1 bellow.
for coil coating
levels for VOC
Emission source Combination of control measures averaging periods:( daily
average for AELc and
yearly average for AELf
and total AEL]
Coil coating – new plants Combination of extraction of the coating 0.73 to 0.84 g NMVOC/m²,
preparation area, paint application, with 3 – 5% fugitive
drier/oven and cooling zone and emissions*
treatment of the waste gases by thermal (concentrations in the
or catalytic oxidation treated waste gas of 20 - 50
mg C/m³ can be reached)
Coil coating – existing 0.73 to 0.84 g NMVOC/m²,
plants with 3 – 10% fugitive
emissions*
(concentrations in the
treated waste gas of 20 - 50
mg C/m³ can be reached)
* New information from ECCA shows that the achievable emission rate depends on a wide variety of factors, but
2
that a figure of <2.5 g/m should be used to cover all foreseeable scenarios, where BAT is adopted. As this value
has not been validated in the BREF, it is not reproduced in the table above.


Abatement costs corresponding to the implementation of a thermal oxidiser vary between about 200
and 360 €/t VOC abated according to the size of the installation. The detailed methodology used to
estimate these costs is defined in the EGTEI synopsis sheet concerning “coil coating“ [2].
Caution: this document is susceptible to evolve if new updated data are available.

The primary technique is secondary abatement through oxidisers. Technology for water-borne and
powder paints are not new, but both systems suffer severe limitations. In the future, the emergence of
radiation-curable paints (using UV and/or EB radiation) may provide VOC-free paint systems for this
sector, but these technologies are not yet commercially adopted [4].

[2] EGTEI synopsis sheet: Coil coating – 2006
[4] Comments from ECCA – 09/03/2009

Mis en forme
7.28 Coating processes 4: coating of metal, wood, plastic and other
surfaces (fabric, leather, paper…etc)
7.28.1 Coverage
Only industrial uses of paints are considered in this section. The use of domestic and architectural
paints is studied in another paragraph. Coating of cars and other vehicles, coil coating and coating of
winding wire are defined in other sections as abatement techniques applied are very specific.

Within this source category, VOC emissions are released from the application of paint, from drying
ovens and from the cleaning of equipment and paint cabins. According to reference [1], due to the
high variety of techniques used and the highly different requirements for the quality of coatings,
uniform reduction techniques can not be defined.
The requirements of the surface coating show significant differences within the sectors of paint
application. The solvent content of products is very variable:
a/ Solvent based paints
Conventional solvent based paints contain approximately 30 to 80 wt. % of organic solvents.
High solid paints have a solid content above 65%.
b/ Water based paints
Water based paints contain from less than 1% to 18% of organic solvents used as solubilizer and for
the improvement of properties of the wet film layer.
These paints are available and are widely used. Their range of application is increasing continuously.
c/ Powder coatings
Powder coatings are solvent free materials. Most often, overspray is recycled so the transfer efficiency
is pretty high. For drying, the material is heated and thus merged into a film. Powder coatings are
mainly applied via electrostatic assisted spraying on the work pieces. In several sectors, this technique
is well established.

BAT AELs are based on the STS BREF [2] for large installations consuming more than 200 tones of
solvent a year and on the SED Directive [3] for smaller installations (associated emission factors are
based on solvent reduction scheme calculations).
a/ General issues
The typical exhaust air from the coating industry has a high flow rate and a low organic solvent
content, which means that energy costs for end-of-pipe measures can be significant. Therefore, if this
option is chosen, processes should be used that have low energy consumption and/or high energy
recovery rates. A further solution is to use a preceding concentration step via adsorption/desorption
processes. The use of low and no organic solvent paints and cleaning methods is in many cases the
most effective means of reducing organic solvent emissions in industrial painting.
Furthermore, for industrial applications, emission reduction technologies exist, such as improvement
of the application processes: e.g. electrostatic guns and other spray techniques instead of
conventional pneumatic application, low solvent-based coating systems, and sometimes
automatisation of application. Also, paint recovery (e.g. overspray recovery) is a proven VOC
abatement option in the wood- and metal-coating sectors.

b/ Specific issues for the wood coating

In the coating of wood materials, water-based coatings are not suitable with oak; powder coatings are
only suitable for MDF (Medium-density fiberboard) and radiation cured coatings are suitable for flat
pieces only.
for coating processes
levels for VOC
Combination of control
Type of installation [Defined for the following
measures
averaging period:( yearly
average for total AEL])
Large installations [2]
Coating of furniture and wood Waste gas treatment such as 0.25 kg or less of VOC / kg of
materials thermal oxidation when other solid input
techniques are not available or
do not achieve suitable levels
Use of low or non-solvent paints
and, maximize efficiency of paint
application
High organic solvent paints 40 – 60 g VOC/m²
(solvent content of w-% 65) with
high application efficiency
technique (rolling, flooding,
electrostatically assisted
spraying, airless spraying) and
good housekeeping
Medium organic solvent paints 10 – 20 g VOC/m²
technique and good
housekeeping
Low organic solvent paints 2 – 5 g VOC/m²
technique and good
housekeeping
Coating of plastic workpieces Waste gas treatment 0.25 to 0.35 kg or less of VOC /
Use of low solvent paints or kg of solid input
water-based paints and,
maximize efficiency of paint
application
Coating of metal surfaces Waste gas treatment 0.10 to 0.33 kg or less of VOC /
Use of low solvent paints or kg of solid input
application
Small installations [3]
Coating of furniture and wood Waste gas treatment such as 1 to 1.6 (for installation
materials thermal oxidation when other consuming less than 25 tonnes
techniques are not available or of solvents per year) or less of
do not achieve suitable levels VOC / kg of solid input

Use of low or non-solvent paints

and, maximize efficiency of paint
application
Use of low solvent paints or
application
Coating of metal and plastic Waste gas treatment 0.375 – 0.6 (for installation
surfaces Use of low solvent paints or consuming less than 15 tonnes
water-based paints and, of solvents per year) or less of
maximize efficiency of paint VOC / kg of solid input
application
According to CEPE [7], for metal and plastic coating 0.375 kg VOC emission per kg NV consumption is
achievable by a combination of very high solids primer and high solids topcoat wet-on-wet which is a suitable
process for many applications. Lower limits may apply for metal surfaces in cases where electrocoat, powder or
other high-bake materials can be used. It might be unachievable for many low bake operations and would trigger
need for abatement of spray-booth exhaust air as undesired add-on measure.
7.28.4 Costs
Costs are defined in the EGTEI documents concerning “paint in the general industry“ [4] and “wood
coating” [5].
For the coating in the industry (general industry, continuous processes, plastic coating), abatement
costs vary between 2 and 18 k€/tonne of VOC abated depending on the size of the installation and are
negative for primary measures (higher application process efficiencies lead to the reduction of solvent
consumptions so less products are used).
For the coating of wood, abatement costs vary from 2 to 16 k€/tonne of VOC abated depending on the
size of the installation and are negative if emissions are reduced by primary measures.

The electrostatically assisted application of powder coatings onto non-conductive wood and wood
materials is under development [2].

[1] BAT for paint and adhesive applications in Germany, IFARE – 2002
[4] EGTEI background document/synopsis sheet: Paint in the general industry – 2003/2005
[5] EGTEI background document/synopsis sheet: Wood coating – 2003/2005
[6] Compilation of the answers-to-questions-and proposal of EGTEI secretariat.doc – EGTEI - 02/2009
[7] Comments from CEPE – March 2009


Mis en forme
7.29 Solvent content in products 1: Decorative coatings
7.29.1 Coverage
Decorative paints are applied in situ to buildings.

VOC emissions from decorative paint use come from evaporation of VOCs, which may be present as
necessary components of the supplied paint or added before application of solvent based paints to
reduce viscosity (thinners) or used as cleaning solvents [3].
All unrecovered VOCs can be considered as potential emissions. The major factor affecting these
emissions is the amount of VOC in the ready for use paint. Paints can be water based - where the
viscosity can be reduced by addition of water - or solvent based where the viscosity is reduced by
addition of solvent.
Conventional solvent based decorative paints typically contained around 50% solids and 50% organic
solvent. The VOC limits of the Product Directive 2004/42/EC [1] require adoption of lower VOC
products.
7.29.3 Available techniques, Achievable Solvent Concentrations

Decorative paint VOC emissions result from use of the ready for use paint and from cleaning of
equipment where this is done with solvents. VOC emissions can be reduced by adoption of lower VOC
paint e.g. by switching use of conventional solvent based paint to lower VOC water based paint or by
adopting lower VOC solvent based paints. The maximum VOC contents permitted under the phase II
of the Product Directive 2004/42/EC are defined by product category in table 1 below.
Table 1: achievable solvent concentrations for each type of paint
Product Subcategory Type Phase II (g/l)*
Interior matt wall and ceilings WB 30
(Gloss ≤ 25@60°) SB 30
Interior glossy walls and ceilings WB 100
(Gloss > 25@60°) SB 100
WB 40
Exterior walls of mineral substrate
SB 430
Interior/exterior trim and cladding paints for WB 130
wood and metal SB 300
Interior/exterior trim varnishes and woodstains, WB 130
including opaque woodstains SB 700
WB 30
Primers
SB 350
WB 30
Binding primers
SB 750
WB 140
One pack performance coatings
SB 500
2 pack reactive performance coatings for WB 140
specific end use SB 500
WB 100
Multi-coloured coatings
SB 100
WB 200
Decorative effects coatings
SB 200
* g/l ready to use

With the exceptions of solvent based interior wall paints, the European Decorative paints industry
believes that in practice these VOC's should be achievable.
Interior wall paints will become entirely water based as the 30g/l and 100g/l limits will not be practically
achievable with solvent based products [3].
7.29.4 Cost data

Costs are defined in the EGTEI background document concerning “decorative paint“ [2]. According to
CEPE [3], this document is outdated. CEPE has prepared a document covering the costs of relabeling
products: this document is available to the group [4].


[1] Directive 2004/42/EC of the European Parliament and of the Council of 21 April 2004 on the
limitation of emissions of volatile organic compounds due to the use of organic solvents in decorative
paints and varnishes and vehicle refinishing products and amending Directive 1999/13/EC
[2] EGTEI background document: Decorative paint – 2003
[3] J. WARNON – CEPE – 02/03/2009
[4] Cost impact of Directive 2004/42/EC. CEPE estimate of relabeling costs for the changes in 2010
for Decorative paints

Mis en forme
7.30 Manufacturing of coatings, varnishes, inks and adhesives
7.30.1 Coverage
This sector covers the manufacturing of all types of paints, varnishes, stains as well as inks and
adhesives. A wide number of products, formulated to meet a variety of service requirements, are
available. These products are destined among others to aircrafts, automobiles, ships, wooden and
metal furniture, packaging, textile fibres, domestic uses etc.

Raw materials used in the products manufacturing process include solids, binders, solvents and all
kinds of additives.
solids provide the coating with colour, opacity, and a degree of durability.
binders are components which form a continuous phase, hold the solids in the dry film, and
cause it to adhere to the surface to be coated. The majority of binders are composed of resins
and drying oils which are to a great extent responsible for the protective and general
mechanical properties of the film.
for viscosity adjustment, solvents are required. Materials that can be used as solvents include
aliphatic and aromatic hydrocarbons, alcohols, esters and ketones.
additives are raw materials which are added in small concentrations. They perform a special
function or give a certain property to the coating. Additives include driers, thickeners, antifoams,
dispersing agents, and catalysts.
Only physical processes such as weighing, mixing, grinding, tinting, thinning, and packaging take
place; no chemical reactions are involved. These processes are carried out in large mixing tanks at
approximately room temperature.
Emission losses may arise from several steps in the process. Major emission sources are:
losses during filling and cleaning activities;
losses from product clinging to the vessels and equipment;
fugitive losses during mixing of preparations and storage of solvents.
7.30.3 Available Techniques, Associated Emissions Levels (AEL)

In the production of coatings, process modifications are possible by switching to low organic solvent
containing paints and glues. Process controls for reducing emissions, such as covering vessels or
reducing storage tank breathing losses can be implemented. Further VOC abatement options are
condensation, adsorption, thermal and catalytic oxidation. Examples of available emission reduction
measures are given in table 1 below.

for manufacturing of paints and adhesives
Emission Combination of control measures Associated emission
source levels for VOC
[Defined for the
following averaging
period:( yearly average
for total AEL])
Large
installations
with an annual 1 wt-% of solvent input
organic solvent [1]
consumption >
1000 t
All other plants Good practices such as:
Recovery of solvent vapours during raw material
distribution,
Unloading of the barrels with fork lifts to avoid
leakages,
Coverage of mobile vessels, 2.5 wt-% of solvent input
Use of solvents with lower volatility to reduce fugitive
emissions,
Use of cleaning agents containing less solvents,
Use of automatic cleaning devices whenever possible,
Recycling of cleaning solutions,
Good practices and upgrading of the condensation or
1.75 wt-% of solvent input
carbon adsorption units and solvent recovery

Abatement costs corresponding to emission levels below 2% of the solvent input are about 2,200 €/t
VOC abated. The detailed methodology is defined in the EGTEI synopsis sheet concerning
“manufacture of paints, inks and glues“ [2].

No data available.

[1] Comments from UBA – this correspond to the German legislation for large installations
[2] EGTEI synopsis sheet: Manufacture of paints, inks and glues – 2005

Mis en forme
7.31 Printing processes
7.31.1 Coverage
The most important techniques in the printing sector are heatset offset, flexography and rotogravure in
the packaging sector, publication gravure and rotary screen printing.
According to Intergraf [10], sheetfed and coldset have very limited VOC emissions. These emissions
are also difficult to measure since there is no forced drying process producing waste gasses. There is
a trend towards the use of low volatility cleaning agents and the avoidance of isopropanol in
dampening solutions. The applicability of these emission reduction measures however depends very
much on locally determined circumstances and cannot be translated in any kind of emission limit
value. For this reason, these processes cannot be covered in the system used for the other printing
processes and should be left out of this document.

a/ Heatset offset
Offset means a printing process using an image carrier in which the printing and non-printing areas
are on the same plane. The non-printing area is treated to attract water and thus reject the greasy ink.
The printing area is treated to receive and transmit ink to a rubber coated cylinder and from there the
surface to be printed.
Heatset means an offset printing process where evaporation takes place in an oven where hot air is
used to heat the printed material (most offset inks do not dry by evaporation, but by oxidation or
absorption in the paper. Heat set inks are the exception. They are the only offset ink drying largely
through evaporation [1]).
Emissions to air arise primarily from the organic solvents contained in inks. Inks used within consist of
high boiling mineral oils as solvents (between 40 and 45 wt.-%). About 20% of the mineral oil remains
in the paper, where once cooled to room temperature, no longer fall within the definition of NMVOC,
and the rest evaporates during the drying stage, which occurs at high temperatures (200 to 300 °C).
Solvents used in cleaning, the storage and handling of solvents and the use of organic solvents as
part of the dampening solutions (commonly isopropanol) are also important sources of emissions of
organic compounds.
b/ Publication gravure
Rotogravure means a printing process using a cylindrical image carrier, in which the printing area is
below the non-printing area, using liquid inks that dry through evaporation. The cells are filled with ink
and the surplus is cleaned off the non-printing area before the surface to be printed contacts the
cylinder and lifts the ink from the cells. Only toluene based inks are used [1]. Ink contains 50% of
toluene when leaving the ink factory. A dilution is made in the printing plant to obtain the proper
concentration in toluene: machine ready ink contains up to 80% toluene [2]. This dilution is made with
toluene recovered inside the plant.
c/ Flexography and rotogravure in packaging
Flexography means a printing process using an image carrier of rubber or elastic photopolymers on
which the printing areas are above the non-printing areas, using liquid inks that dry through the
evaporation of organic solvents. The process is usually web fed and is employed for medium or long
multicolour runs on a variety of substrates, including heavy paper, fibreboard, and metal and plastic
foil. The major categories of the flexography market are flexible packaging and laminates, multiwall
bags, milk cartons, gift wrap, folding cartons, corrugated paperboard (which is sheet fed), paper cups
and plates, labels, tapes, and envelopes. Almost all milk cartons and multiwall bags and half of all
flexible packaging are printed by this process.
Solvent based inks can have different solvent contents when bought but ready to use inks contain
about 80 to 90% of solvents (these figures take into account cleaning agents). Substitution can be
implemented with water-based products (containing about 5% of solvent), UV curing inks and 2-

components adhesives. Water-based inks in flexography printing are in regular production use in
some packaging applications such as paper bags and plastic carrier bags [1].

BAT AEL and techniques are based on the STS BREF [3] when information is available (for large
installations consuming more than 200 tones of solvents a year) and on the SED Directive [4] or
EGTEI data for smaller installations. For screen printing, data are based on a study from 1999 [ 5] as
this sector has not been treated specifically by EGTEI.
a/ Heatset Offset
NMVOC emissions from heatset printing consist of isopropanol (IPA) emitted from the dampening
solutions, from cleaning agents and the stack emissions from dryers. BAT is to reduce the sum of
fugitive emissions and to treat stack VOC emissions with thermal, catalytic or regenerative oxidation.
It is then BAT to reduce:
the emission of IPA by using low IPA or free-IP dampening solution,
fugitive emissions from the cleaning process by a combination of the following techniques:
substitution and control of NMVOC used in cleaning, automatic cleaning systems for printing
and blanket cylinders.
Table 1: BAT associated emission levels for heatset offset

Type of press BAT associated emission levels for VOC
[Defined for the following averaging periods:( daily average
for AELc and yearly average for AELf and total AEL]
IPPC installations [1]
For new and upgraded presses 2.5 to 10% VOC expressed as % of the ink consumption by
weight
For existing presses 5 to 15% VOC expressed as % of the ink consumption by weight
Smaller installations
For all presses Fugitive emissions lower than 30% of solvent input can be
reached [1] with concentration in the stack not greater than 20
3
mg C / Nm
b/ Publication gravure
In the publication rotogravure sector, more than 90% of the organic solvent consumption can be
recovered, if activated carbon adsorption is used, due to the small number of components in the
organic solvent (mainly toluene). The recycling of these organic solvents is possible and has long
been practiced.
It is BAT to reduce fugitive emissions remaining after gas treatment:
Table 2: BAT associated emission levels for publication rotogravure

For new installations [3]
[Defined for the following averaging periods:( yearly average for total AEL])
Total emissions of 4 to 5% of solvent input
For existing installations [3], [4]
[Defined for the following averaging periods:( yearly average for total AEL])
Total emissions of 5 to 7% of solvent input

c/ Packaging rotogravure and flexography

In the packaging rotogravure and flexography sector, the following control measures for VOC
emissions can be used:
Substitution with low solvent or solvent-free inks, and adhesives where practicable;
Activated carbon adsorption: the efficiency of the capturing system is an important parameter for the
overall efficiency. Due to the numerous organic solvents in the inks, recycling on-site is difficult. This
option may be technically and economically feasible for large printing installations with an annual
solvent consumption of at least 500 Mg. The optimisation of the captured air flow at the different parts
of an installation is always advisable when designing an installation. Minimizing the overall air flow rate
and thus increasing the inlet concentration results in considerable savings in investments and
operating costs;
Thermal or catalytic oxidation: the efficiency of the capturing system is an important parameter for the
overall efficiency. At present, this measure is the most commonly used to reduce VOC emissions in
this part of the printing sector, and it is expected to remain the most favourable option from an
economic point of view for printing facilities with a solvent consumption of less than 500 Mg/year. The
optimization of the captured air flow at the different parts of an installation is always advisable when
designing an installation. Minimizing the overall air flow rate and thus increasing the inlet concentration
results in considerable savings in investments and operating costs.
for packaging rotogravure and flexography
Type of installation Combination of control BAT associated emission
measures levels for VOC
averaging periods:( daily
average for AELc and yearly
average for AELf and total
AEL]
IPPC installations For plants with all machines 7.5 to 12.5% of the reference
a/
connected to oxidation emission [3]
For plants with all machines 10 to 15% of the reference
a/
connected to carbon adsorption emission [3]
For existing mixed plants: where Emissions from the machines
some existing machines may not connected to oxidisers or carbon
be attached to an incinerator or adsorption are below the
solvent recovery emission limits of 7.5 to 12.5% or
10 to 15% respectively
For machines not connected to
gas treatment: use of low solvent
or solvent free products,
connection to waste gas
treatment when there is spare
capacity and preferentially run
high solvent content work on
machines connected to waste
gas treatment.
Total emissions below 25% of
reference emission (requirement
reduction scheme SED)
3
Smaller installations AELc = 100 mg C/Nm and AELf = 20 wt-%
Or total AEL = 25% of reference emission a/ which can be reached
with the following measures
Switch to water-based inks (5 50 g/kg of product ready to use

wt.-% solvent content) (Abatement efficiency ~ 94%)
[6]

Solvent based products and Abatement efficiency ~ 76%

treatment of stack emissions by [5]
oxidation
60% of products with no-solvents ~ 80 g/kg of product ready to use
and treatment of stack emissions (Abatement efficiency ~ 90%)
for the remaining 40% [6]
a/
Using the reference emission defined in annex IIb to the SED [4]

The detailed methodologies developed to estimate costs are defined in the EGTEI synopsis sheets
concerning “heatset offset” [6], “packaging” [7], and “publication gravure” [8].
For heatset offset, abatement costs for the implementation of an oxidiser vary between about 1 and 5
k€ according to the size of installations.
For the packaging industry, abatement costs are very dependant of the installation’s size: for small
installations, the use of an oxidiser costs around 22 k€/t NMVOC abated versus less than 1 k€/t
NMVOC for the biggest installations. For all types of installations, when the use of water-based inks is
technically feasible, this option will lead to costs around 0.15 k€/t NMVOC abated. The last option,
technically and economically available only for large installations, is the implementation of carbon
adsorption leading to abatement costs below 1 k€/t NMVOC.
For the publication gravure, abatement costs to reduce emissions by carbon adsorption are about 1
k€. Abatement costs are reduced because a large amount of toluene can be recycled.

It is likely that UV curing flexo printing, for purposes other than beverage cartons, will be developed in
the future [3].

[1] P. VERSPOOR for INTERGRAF – Communications for EGTEI and IIASA – 2002 to 2004
[2] J. BERNARD for ERA. – 2003
[4] Directive 1999/13/EC of 11 March 1999. on the limitation of emissions of volatile organic
[5] Task Force on the Assessment of Abatement Options/Techniques for VOC from Stationary
Sources – 1999
[6] EGTEI synopsis sheets: Heatset offset – 2005
[7] EGTEI synopsis sheets: Packaging – 2005
[8] EGTEI synopsis sheets: Publication gravure – 2005
[9] Compilation of the answers-to-questions-and proposal of EGTEI secretariat.doc – EGTEI - 02/2009
[10] Comments from Intergraf – 25/03/2009 and 25/05/2009

Mis en forme
7.32 Rubber processing
7.32.1 Coverage
This sector concerns the production of tyres as well as the production of all other rubber goods.
Adhesives used in the production of some rubber goods are considered in the section on adhesive
coating. Reduction techniques are not the same as the one defined below.

Products made of rubber are produced using a large variety of materials. The main process steps are:
mixing;
extrusion;
calendering;
building;
curing (Vulcanisation).
Within the conversion of natural or synthetic rubber, organic solvents are mainly used for tackifying.
7.32.3 Available techniques, Associated Emissions Levels (AEL)

Reference documents on Best Available Techniques in the production of tyre and general rubber
goods do not exist. The existing document addresses "Production of Polymers" which is not covered
by the sector named "rubber processing" [4].
In this sector, VOC emissions will be reduced either by primary or secondary measures but generally,
not by a combination of the 2 approaches. Most of the time, emissions will be reduced by switching
solvent-based to low or non-solvent based products. When no technique is available, waste gas
treatment might be used. Associated emission factors are based on the EGTEI document for the
production of tyres [1] and on a study from 1999 for the production of rubber goods [2]. Considering
the very large variety of installations and products manufactured and the fact that no BREF has been
developed for this sector, achievable emission levels defined in table 1 are only indicative and have
to be understood as average values.

for the production of natural or synthetic rubber goods
Emission source Combination of control measures VOC emission levels
[Defined for the
following averaging
period:( yearly average
for total AEL)]
Rubber goods production
Plant with a solvent Partly switch from solvent-based to water- 1 kg/tonne rubber
consumption ≥ 15 tonnes based agents and cleaning systems produced [2]
/year or
waste gas treatment such as oxidation
Tyre production
All plants New processes (example: adhesive rubber 2.5 kg/t of tyre
band use – New type of building machine [1]
(1)
associated with extruder – New technology

extrusion).
Use of 25 % solvent-based adhesives,
coatings, inks and cleaning agents (90 wt.-
% solvent content)
or
oxidation when reduction of solvent
consumption is not suitable
(1) The VOC emission level of 2.5 kg VOC/t of tyre is derived from the EGTEI background document on tyre
production [1]. This is the result of the application of a 75% reduction to the average non-abated situation
(which includes also plants in which reduction measures had been already implemented)

Costs are defined in the EGTEI synopsis sheet concerning “tyre production“ [1].
For the production of tyres, abatement costs defined, for an average installation, vary between 0.14
and 1 k€/tonne of VOC abated according to the technique implemented (i.e. solvent consumption
reduction or thermal oxidation). In most of the cases, secondary measures will be implemented only
when primary measures are not technically applicable.


[1] EGTEI synopsis sheet: Tyre production – 2005
[2] Task Force on the Assessment of Abatement Options/Techniques for VOC from Stationary
Sources – 1999
[3] Comments from ETRMA – March/April 2009

7.33 Dry cleaning

7.33.1 Coverage
This sector covers dry cleaning of textiles, leather and furs. Dry cleaning relates to cleaning of fabrics
with organic solvents.

In dry-cleaning, solvents such as perchloroethylene (PER) and light hydrocarbons (which are
flammable) are mainly used today. Hydrocarbons with higher flash point are also used. In Germany
where these solvents are used in dry cleaning, the requirements for use are as follows [6]: ebullition
temperature between 180 and 210 °C, flash point larger than 55°C. They are less volatile than
perchlorethylene. Consequently the drying cycle is longer. They have a lower Kb value than PER and
are consequently less efficient than PER for some types of products to be removed (the Kauri butanol
value (Kb) measures the cleaning power of the solvent, the higher the Kb, the more aggressive is the
solvent).
Significant VOC emissions of solvents from dry-cleaning machines can be divided into two categories:
discharge of vapour, including venting of machines, air discharge from storage tanks during
filling, leaks and solvent retained temporarily on cleaned clothes;
residues left outside.
Presently some other types of organic solvent emerge. One of them is the Siloxane D CAS 541-02-6,
5
a liquid silicone. Its vapour pressure at 20°C is 0.03 kPa. This product is attractive however it is not
free of impact on human health according to studies carried in USA and Denmark [4] and [5]. The use
of liquid is still marginal but is growing [8]. For any substitution of current solvents used in dry
cleaning, special attention has to be paid to classification of solvents (see chapter 5.1).
.
There are 4 types of dry cleaning machines presently in operation [1]:
Machine type I: this type of machine has only a water cooled unit at a temperature of 20-30°C to
condense the solvent. After water cooling, the solvent laden air is exhausted without an activated
carbon filter. The emissions to air are about 105 g solvent/kg textiles. The solvent consumption is
about 110 g solvent/kg textiles.
Machine type II: this type of machine has a refrigeration cooling unit condensing perchorethylene at a
temperature of -20°C. The exhaust air passes an activated carbon filter before being exhausted. The
emissions to air are about 45 g solvent/kg textiles. The solvent consumption is about 50 g solvent/kg
textiles.
Machine type III: this type of machine is a closed machine with a closed drying cycle where the drying
air is recirculated through a refrigeration cooling unit. There is no exhaust air released. The assumed
emissions to air are about 20 g solvent/kg textiles and the range of emissions 20 to 40 g solvent/kg
textiles. The solvent consumption is about 25 g solvent/kg textiles.
Machine type IV: this type is totally closed with a closed drying cycle similar to type III. In this case,
the air stream for drying cycles, circulates through the refrigeration cooling unit and the activated
3
carbon, until the concentration of solvent in the turning cage is below 2 mg/m . The solvent from the
adsorption phase of the activated carbon adsorber is returned into the machine. The assumed
emissions to air are about 5 g solvent/kg textiles. The solvent consumption is about 10 g solvent/kg
textiles.

7.33.3 Available Techniques, associated emission levels

Wet cleaning
A generally applicable primary measure with a high emission reduction potential consists in switching
to wet cleaning processes with water
Wet cleaning use water to clean clothes that are typically dry cleaned. A special detergent and sizing
formulated for wet cleaning applications is used. Both products are automatically dispensed to the
machine at quantities set by the individual cycle programs. The detergent is a combination of active
detergents, glycol ether, anti-shrinking agents, and alcohol dissolved in water. Occasionally, starch
and other spot cleaners are used, some of which may contain hazardous chemicals. Wet cleaning is
carried out in computer controlled washing and dry machines. The main cross media effect is water
pollution. The quality can be lower than with solvent dry cleaning as fabrics can be deteriorated as
colours. Restrictions with regard to leather and fabric have to be accounted for.
New generation dry cleaning machines

By introducing new generation closed-circuit machines (equipped with a condenser and an activated
carbon filter), like type IV machines described above, VOC emissions can be reduced by 95% in
comparison to open machines. Conventional closed-circuit machines with activated carbon filters can
only reduce emissions by 80 %.
Table 1: emission sources and selected available techniques with associated emission levels
Available Technique
Associated
Combination of control Emission Levels for
Emission source VOCs
measures
(yearly average for
total AEL)
Switch to wet processes with 0 g/kg textiles cleaned

Open circuit machine and conventional
water
closed machines (type I to type III machines)
Switch to the newest
generation type IV machine
Solvent used : (closed machine with 5 g/kg textiles cleaned
perchlorethylene (PER) or hydrocarbons refrigeration cooling and
activated carbon)

Liquid CO2 cleaning
Liquid CO2 cleaning machines already exist but are not yet widely spread. Like in a conventional
process, liquid CO2 cleaning machines have a cleaning chamber, a circulation loop, a filtration system,
a lint trap, a distillation unit and storage. The equipment and chemistry is specially developed to house
the pressure and interact with carbon dioxide. Garments have not to be dried after cleaning. Due to its
low viscosity, liquid CO2 enables to clean garments easily. Its performance is comparable to PER. A
slight difference in cleaning performance is dirty motor oil and lipstick. However, these stains can be
pre-spotted or post-spotted for complete stain removal [6].
Water less washing machines
The process is based on the use of plastic granules that are tumbled with the clothes to remove
stains. The water consumption of 100 ml/kg garments is very low compared to traditional wet cleaning
machines [8].


Costs are defined in the EGTEI background document concerning dry cleaning [3]. Investment cost of
the last generation closed circuit machine is approximately 25 % higher than a conventional closed
circuit machine.

[1] Institute for health and consumer protection European Chemical Bureau. Risk assessment report
for tetrachloroethylene. Final report 2005 – EUR 21680 EN
[3] EGTEI background document: Dry cleaning – 2005
[4] Siloxanes in the Nordic Environment, TemaNord 2005 : 593 Nordic Council of Ministers,
Copenhagen 2005 - ISBN 92-893-1268-8
[5] EPA study on siloxanes
[6] INERIS – rapport d’étude ERSA 05 9 – Note sur les produits de substitution du perchloroéthylène.
[7] Birgit Mahrwald UBA Comments on GD 7-36 dry cleaning version 1
[8] AEA energy and environment, OKOPOL and BIPRO: Guidance on VOC substitution and reduction
for activities covered by the VOC solvent emissions directive – Guidance 11 - Dry cleaning –
European commission 2008

and black carbon)from stationary sources
Mis en forme
7.34 Surface cleaning
7.34.1 Coverage
This chapter covers stack and fugitive VOC emissions from cleaning processes using solvents carried
out in industry. The metalworking industries are the major users of solvent cleaning, i. e. automotive,
electronic, plumbing, aircraft, refrigeration and business machine industries. Solvent cleaning is also
used in activities such as printing, chemical industry, plastic processing, rubber processing, textile
processing, mirror manufacturing, paper industry and electric power and solvents are used for paint.
Most repair stations for road vehicles and electronic tools use solvent cleaning at least part of the time.

Surface cleaning with solvent (often named solvent degreasing) is the process of using organic
solvents to remove water-insoluble residues such as grease, fats, oils, waxes, carbon deposits, fluxes
and tars from metal, plastic, fibreglass, printed circuit boards and other surfaces.
Several types of degreasing agents for surface cleaning are used:
organic solvents, halogenated or not halogenated,
aqueous solutions with use of alkalis, acids, silicates, phosphates and complexing and wetting
agents [1],
supercritical CO2,
biological agents,
ultrasonic degreasing.
Organic solvents used in degreasing applications, are:

chlorinated solvents. They are not flammable (no flashpoint) but many of them are classified
R40 (perclorethylene and methanedichloride) or R45 (trichlorethylene),
hydrocarbon solvents or A3 class solvents (flash point larger than 55°C meaning these solvents
are not flammable under current uses but can become flammable during non controlled uses
(flammable solvents have a flash point < 55° C)),
alcohols and ketones which are flammable,
HFC hydrofluorocarbons, HFE hydrofluoroethers, PFC perfluorocarbons used in special
cleaning applications such as electronic whose main concern is their potential impact on
stratospheric ozone even if their ODP (ozone depletion potential) is low but also climate change
(PFC and HFC are green house gases regulated under the Kyoto Protocol). HFE are included
in the fourth assessment report of IPCC (AR4) [5].
Solvent cleaning is most often used when the metallic part has to be dried after degreasing.
The following parameters have a great influence on the choice of the surface cleaning process:
the medium to be cleaned,
the type of impurity to be removed,
the manufacturing process,
the requirements induced by subsequent process steps.

The degreasing methodologies surface cleaning techniques can be summarized as followsin the
following table:
Table 1: main surface cleaning techniques
Process Type of machine Cleaning product used

Manual (with a chiffon as
example) Alcohols
Cold cleaning
Open machines Chlorinated solvents
Closed machines
Open top machines
Covered open top machines
Chlorinated solvents
Closed machines
Closed sealed machines
Hot cleaning
Open top machines
Covered open top machines
Hydrocarbons
Closed machines
Closed sealed machines
Mono tank machine, Alkalis, acids, silicates,
Aqueous cleaning Multi tank machines phosphates, complexing and
Tunnel machines wetting agents
With organic solvents, two types of process exist [1], [2]:

cold cleaning : cold cleaners are mainly applied in maintenance and manufacturing. They are
batch loaded, non-boiling solvent degreasers. Cold cleaner operations include spraying,
brushing, flushing, and immersion. In a typical maintenance cleaner, dirty parts are cleaned
manually by spraying and then soaking in the tank. After cleaning, the parts are either
suspended over the tank to drain or are placed on an external rack that routes the drained
solvent back into the cleaner. The cover is intended to be closed whenever parts are not being
handled in the cleaner. Typical manufacturing cold cleaners vary widely in design, but there are
two basic tank designs: the simple spray sink and the dip tank. Of these, the dip tank provides
more thorough cleaning through immersion, and often is made to improve cleaning efficiency by
agitation.
vapour cleaning: vapour degreasers are batch loaded boiling degreasers that clean with
condensation of hot solvent vapour on colder metal parts. Vapour degreasing uses halogenated
solvents (usually perchloroethylene, trichloroethylene), because they are not flammable and
their vapours are heavier than air. A typical vapour degreaser is a sump containing a heater that
boils the solvent to generate vapours. Parts to be cleaned are immersed in the vapour zone,
and condensation continues until they are heated to the vapour temperature. Residual liquid
solvent on the parts rapidly evaporates as they are slowly removed from the vapour zone.
Cleaning action is often increased by spraying the parts with solvent below the vapour level or
by immersing them in the liquid solvent bath. Nearly all vapour degreasers are equipped with a
water separator which allows the solvent to flow back into the degreaser.
For cold cleaners, bath evaporation can be controlled by covering the bath regularly, by using an
adequate freeboard height, and by avoiding excessive drafts in the workshop.
For open-top vapour systems, most emissions are due to diffusion and convection, which can be
reduced by covering the bath automatically or manually, by spraying below the vapour level, by
optimising work loads, or by using a refrigerated freeboard chillers (which may be replaced, on larger
units, by a carbon adsorption device).
Vapour cleaning can be carried out in closed sealed machines.
Hermetically sealed machines

These types of machines prevent direct exposure between the solvent and the atmosphere by a series
of interlocks, and by the use of a vapour extraction and/or refrigeration system which recycles the
vapour back into the solvent sump. This provides an extremely high degree of solvent containment
and reduces fugitive emissions. These machines can work either with chlorinated solvents or with
other solvents like A3 class hydrocarbons, HFC or HFE. As an option, the complete cleaning device
can be operated under a vacuum. This enables distillation at lower temperatures and allows a
permanent control of the vapour emissions [3].
Aqueous based cleaning systems

This technique consists of water, detergent and a small amount of solvents, and has been shown to
provide a reasonable cleaning efficiency for certain applications. Besides acid cleaning baths, strong
till weak alkaline and neutral products are used for industrial cleaning of hard surfaces. Neutral
cleaners are predominantly applied for intermediate and final surface cleaning, whereas strong
alkaline products aim at obtaining highly cleaned surfaces before surface ennoblement, phosphatation
or coating processes. Acid products are found in special applications. Water-based cleaning agents
can be used for the cleaning of metals such as steel, aluminium, magnesium, copper, etc., but also for
plastics, coated surfaces, glass and electronic parts. In large parts of industrial surface cleaning,
water-based systems have been established, leading partly to even better cleaning results as former
solvent-based systems. This effect is especially related to further processing of the substrate, such as
coating. The two main techniques used in aqueous systems are immersion (small tanks to multi-tanks
system) and aspersion (small machines interoperations with complete tunnels).
Biological cleaning process

This technology is based on a water-based cleaning agent combined with an integrated microbiology
for the degradation of oils and grease. The water-based cleaning solution is light alkaline to allow the
degreasing of a wide range of metals (e. g. copper, iron, aluminium, zinc).The used micro organisms
are natural, their living conditions are optimised and continuously controlled via a computer system in
order to keep the determinant parameters of the milieu optimal. In order not to endanger the micro
organisms, the cleaning temperature is kept between 40 and 45 °C (but can go down to 35°C in
certain systems) and the pH-value must remain around 9. The cleaning agent is regenerated via
automatic dosage. When comparing to conventional degreasing processes, the amount of generated
waste water is in this case much smaller. Some substances cause damage to the micro organisms, or
worse kill them; among these substances are chlorinated products, whose degradation has not yet
been clarified. The main applications encountered are degreasing fountains for maintenance cleaning
in the cold cleaning application.

General emission reduction options in this sector are [1]:
minimisation of the amount of grease and oil, selection of oils greases or systems that allow the
use of the most environmentally friendly degreasing systems
mmprovement of equipment:
- cold cleaning : systematic use of covers, reduction of pulverisation pressure,
- vapour degreasing : systematic use of closed sealed machines for vapour degreasing
with chlorinated solvent, hydrocarbons or other solvents such as HFE, HCFC and PFC
- Higher freeboards for the reduction of organic solvent losses for degreasing baths;
refrigerated freeboards for degreasing baths associated with activated carbon adsorption.
substitution of solvent based cleaning agents:

all solvents such as trichloroethylene which are classified as carcinogenic compounds, have to
be substituted if not used in safe and hermetically sealed machines.
- vapour degreasing : use of aqueous based cleaning agent (using also the BAT defined
for these processes [1]),
- cold cleaning : biological agents, use of fatty acids of natural or synthetic esters |3].
regeneration of used organic solvents on-site or by an external regenerator;

switch to low-temperature plasma processes (still using some organic solvent).

Examples of emission reduction measures and performances in surface cleaning are presented in
table 12
Table 12: emission sources and selected VOC control measures with associated emission
levels for surface cleaning [2]
Associated
emission levels
Emission source Available techniques for VOCs
(yearly average for
total AEL)
0 g/kg solvent
Vapour cleaning using Water-based degreasing systems
used*
halogenated solvents or
hydrocarbons Less than 0.1 %
Hermetically sealed machines
solvent used*
* sum of I1 the quantity of organic solvents or their quantity in preparations purchased which are used as input
into the process in the time frame over which the mass balance is being calculated and I2 the quantity of organic
solvents or their quantity in preparations recovered and reused as solvent input into the process. (The recycled
solvent is counted every time it is used to carry out the activity).

Supercritical CO2
The principle of this technique is that at supercritical conditions (beyond 75 bars and 35°C),
intermediary between liquid and gas, CO2 has solvent properties which have the advantage to be
adjustable with the variation of temperature and pressure. This clean solvent is easily recoverable in
making it passing again in a gas stage at the end of the cycle. Nevertheless its cleaning power is
limited: it works well for non-polar products but is less efficient with polar products. This difficulty can
be surmounted by adding few percent of co-solvent or using an ultra-sonic mechanical effect.
Plasma degreasing
This technology is already applied in some specific production sectors and can be applied to a large
variety of substrates leading partly to even better cleaning results than former solvent systems. This
effect is especially related to further processing of the substrate, such as coating of certain plastics
with water-based paints. Thus, a double emission reduction may be achieved in some cases. Within
the plasma degreasing process, surface cleaning is carried out at temperatures below 100 °C and a
-3
pressure between 0.1 and 2.10 hPa. The vacuum chamber is filled with process gas, such as noble
gases (e. g. argon, helium), fluorine containing gases (e. g. tetrafluoromethane) or oxygen. An electric
field conveys energy to the system, resulting in ionised gas particles. Oxygen is mostly used as
process gas. Radicals generated via excitation aim at cutting the hydrocarbon chains and oxidise
them to form carbon dioxide and water. The cleaning effect of the plasma is based on this chemical
reaction. Organic impurities can be removed by this degreasing process, but plasma technique is not
adapted to inorganic impurities such as shavings, mineral dust or salts.

Costs are defined in the EGTEI synopsis sheet concerning “surface cleaning“ [2].
Costs range from 0.4 to 56 € / kg VOC abated in the smallest installation and from – 0.3 to 2.97 € / kg
VOC in the largest one.

[1] European commission BREF for the surface treatment of metals and plastics – August 2006
[2] EGTEI synopsis sheet: Surface cleaning – 2005
http://www.citepa.org/forums/egtei/27-Synopsis-sheet-surface%20cleaning-30-09-05.pdf
[3] Biosolvants – Enjeux et opportunités – 27 mai 2008 – ADEME

[4] AEA energy and environment, OKOPOL and BIPRO: Guidance on VOC substitution and reduction
for activities covered by the VOC solvent emissions directive – Guidance 4/5 – Surface cleaning –
European commission 2008
[5] A compilation of technical information on the new GHG gases and groups included in the Fourth
Assessment Report (AR4) of the Intergovernmental Panel on Climate Change
http://unfccc.int/national_reports/annex_i_ghg_inventories/items/4624.php

Mis en forme
7.35 Vegetable oil and animal fat extraction and vegetable oil refining
7.35.1 Coverage
Activities covered relate to the vegetable oil and animal fat extraction and vegetable oil refining
activities. The definition is as follows [1]: Any activity to extract vegetable oil from seeds and other
vegetable matter, the processing of dry residues to produce animal feed, the purification of fats and
vegetable oils derived from seeds, vegetable matter and/or animal matter.
However, presently, due to the problem of bovine spongiform encephalopathy, the solvent extraction
of animal fat from dead cows and other animals, for producing animal meals is not more carried out
according to [4]. This chapter consequently covers only vegetable oil extraction.

The production of crude vegetable oil from oilseeds (e.g. soya beans, sunflower seeds or rapeseed) is
a two-stage process:
the first process step is cleaning, preparation (i.e. drying) and in some cases dehulling, flaking
and conditioning and pressing of the oilseeds. Pressing takes place in one or two steps,
resulting in crude pressed oil and a cake.
Beans (with 20% oil or less) are not pressed, because of the lower fat content, but are extracted
directly after cleaning and preparation.
the second process step is the extraction of oil from the pressed cake or flaked beans using
hexane as a solvent. Extraction takes place in counter-current flow desolventiser-toaster (DT)
by means of direct or indirect steam.
The mixture of hexane and oil, called miscella, is further processed in a distillation process, to
separate the hexane from the vegetable oil. The solvent is re-used in the extraction process. Oil is
further refined to become consumable.
The hexane remaining in the cake is recovered by a stripping process, using steam. This
desolventising-toasting process also reduces the enzyme and micro organism activity in the meal.
The meal is dried and cooled by air before storage in silos or before loading.
Refining consists in several operations which can be physical or chemical. Conventional chemical
refining includes degumming for the removal of phospholipids, neutralization for the removal of free
fatty acids (ffa) and bleaching for decolourisation and deodorization.
VOCs emissions arise from the oil extraction process. Fugitive and stack emissions occur. The
refining process is not the main source of VOC emissions however VOC emissions arise from the
neutralisation and the deodorisation steps. Dust emissions arise from the drying of desolventised and
toasted meals. Excess moisture in removed by heated ambient air and after, by cooled ambient air.
The exhaust air contains dusts [3].

For the extraction of vegetable oil and the refining of vegetable oil, several VOC emission reduction
options are available.
Batch and continuous processes are to be distinguished in terms of emission relevance, the former
are more relevant. By introducing the so-called Schumacher-type desolventizer-toaster-dryer-cooler in
the edible and non-edible oil extraction sector, VOC emissions can be reduced significantly.
For reducing emissions, several techniques can be used [2] and associated and are constituted of:
Process optimisation: the counter current flow Desolventizer-Toaster (DT) allowing to minimize the
solvent losses and steam consumption, the heat integration of DT vapour stream with miscella

distillation in the extraction process leading to an optimisation of the energy consumption, the mineral
oil scrubbing system to reduce VOC emissions and the reboiler minimising solvent losses.
Use of secondary measures by Condensation/Physical Separation/Distillation: the hexane and

steam vapours coming from the meal desolventising/toasting, from the miscella (crude vegetable oil
and hexane) distillation, from the reboiler and from the stripping column of the mineral oil system, all
pass through a condenser system. The condensed vapours (hexane-water condensate) go to the
hexane-water separator where the undissolved hexane is separated by means of gravitational phase
separation. The hexane is re-circulated to the extraction process. Any residual solvent content in the
aqueous phase of the hexane/water separator is distilled off in the so-called re-boiler. The resulting
hexane/water vapours from the reboiler are condensed together with the vapours from the distillation
stage.
After boiling the almost hexane-free water is fed to the waste water system. This technology also
ensures the explosion safety of this downstream system.
Use of secondary measures by Absorption/Desorption

The components that cannot be condensed by the condenser are treated further by an absorption
technique, the so-called mineral oil scrubbing system, where residual hexane is absorbed. The
mineral oil system consists of an absorption column, where the hexane is absorbed by cold, food
grade mineral oil. The hexane is then recovered by steam stripping the hexane laden mineral oil in a
stripping column. The stripped mineral oil is cooled down and reused in the absorption column.
The final emissions from the mineral oil system consist of the non-condensables with traces of
hexane.
The hexane and steam vapour from the mineral oil stripping column are condensed in the condenser
system. The hexane-water condensate then goes to the hexane-water separator (see above). The
total recovered hexane is reused in the extraction process.
Dusts are removed by cyclones for safety reasons. The use of fabric filters and electrostatic
precipitators increase the fire hazard and cannot be used.
BAT for this sector is consequently to [3]:
use of a counter flow desolventizer toaster (Schumacher type as example)
use the vapour generated in the desolvantiser toaster in the first step of the miscella distillation
pre-evaporator,
use water ring pumps to generate an auxiliary vacuum for oil drying, oil degassing or minimising
oxidation of oil,
use a mineral oil scrubber to recover hexane from incondensable vapours from meals
desolventising toasting, miscella distillation, the reboiler and from the stripping column of the
mineral oil system,
use cyclones to reduce wet dust emissions arising from vegetable oil extraction, to achieve a
3
wet dust emission level of less than 50 mg/Nm ,
better control deviations from normal operating conditions and avoid start-ups and shut-downs
[2] (this is however depending on the number of different types of seeds to treat in the year and
much more difficult if this number high).
[Achievable emission levels were defined in the EGTEI background document assuming biofiltration
use. However, according to FEDIOL, biofiltration is not feasible due to the very limited water solubility
of hexane. The achievable emission level given in the previous Gothenburg Protocol guidance
document III has also been modified according to data defined in the EGTEI background document
[2]].

Table 1: control measures with VOC associated emission levels for extraction of vegetable oil
emission levels for
VOC
[Defined for the
following averaging
period: (yearly
averagefor total
AELfor total AEL)]
Extraction of oil from seed, Process optimization and counter flow 0.5 g/kg seed
continuous process from desolventizer-toaster-dryer-cooler and processed
rapeseeds, sunflower seeds condensation with further absorption (mineral oil
and soya beans. scrubbing system) and other techniques [2]
Extraction of oil from other described above
3 g/kg seed
seeds such as safflower processed
seed, mustard seed, cotton
seed and vegetable material [as in [3]]
Extraction of seeds in batch 4.0 g/kg seed
process processed
All fractionation processes : 1.5 g/kg seed
excl. degumming: processed
Degumming:
4.0 g/kg seed
processed
[as in [3]]

Costs have been defined in the EGTEI documents [2]. Abatement costs defined are negative as
investments lead to hexane consumption reduction.


[2] EGTEI background document/synopsis sheet: Fat edible and non-edible oil extraction – 2003/2005
[3] European Commission - reference document on BAT for the food, drink and milk industries -
August 2006
[4] M. GESLIN from National federation of fat compounds (Fédération Nationale des Corps Gras) –
Information to CITEPA – September 2008


248
Mis en forme
7.36 Vehicle refinishing
7.36.1 Coverage
This sector covers the coating of road vehicles, or part of them, carried out as part of vehicle repair,
conservation or decoration outside manufacturing installations as considered in annexe IX.
Vehicle refinishing comprises coating and surface cleaning activities.

The main VOC emission sources in this sector are the application of paint, the drying operations, the
cleaning of equipment, and the cleaning operations before the coating and between the applications of
different layers.

Emission reduction can be achieved by primary measures such as good housekeeping, low organic
solvent containing paints (including water-based systems), high-volume, low-pressure (HVLP) guns,
and gun cleaning devices. Secondary measures are normally not applicable for economic and
efficiency reasons.
The maximum VOC contents permitted under the Product Directive 2004/42/EC are defined by
product category in table 1 below.
Table 1: achievable solvent concentrations for each type of paint

1 2
Product Subcategory Coatings VOC (g/l)
Preparatory 850
Preparatory and cleaning
Pre-cleaner 200
Bodyfiller/stopper All types 250
Surfacer/filler and
540
Primer general (metal) primer
Wash primer 780
Topcoat All types 420
Special finishes All types 840
1
Product subcategories are defined in annex XI
2
g/l of ready for use product. Except for “preparatory and cleaning”, any water content of the product ready for use should be
discounted.

Abatement costs corresponding to the respect of the Directive 2004/42/CE are about 1,400 €/t VOC
abated. The detailed methodology used to estimate these costs is defined in the EGTEI synopsis
sheet concerning “vehicle refinishing“ [1].

Further reductions seem to be possible.
5 JulySeptember 2012 Page 249


[1] EGTEI synopsis sheet: Vehicle refinishing – 2005
[2] Directive 2004/42/EC of the European Parliament and of the Council of 21 April 2004 on the
limitation of emissions of volatile organic compounds due to the use of organic solvents in decorative
paints and varnishes and vehicle refinishing products and amending Directive 1999/13/EC
5 JulySeptember 2012 Page 250

Mis en forme
7.37 Wood impregnation
7.37.1 Coverage
This sector covers the wood impregnation in organic solvent-based preservatives, creosote and water-
based preservatives. Wood preservatives may be supplied for both industrial and domestic use. Only
industrial applications are treated in this section.

Wood is preserved to protect it against fungal and insect attack and also against weathering. Different
types of preservatives are used [1]:
solvent-based preservatives: traditional preservative systems consist of approximately 10%
active ingredient and 90% organic solvents, usually whit spirit or other petroleum -based
3
hydrocarbons. Without additional measure, the reference VOC emission is about 19.8 kg/m of
wood treated, concentrated pesticide systems: these are solvent-based solutions with a higher
concentration of pesticides,
water-based preservatives: they consist of solutions of salts in water. VOC emission reductions
above 99% are observed compared to the reference situation,
creosote: it is an oil prepared from coal tar distillation. Approximately 10% of the creosote used
for wood preservation is made up of VOC.
The estimation of emissions can either be based on the quantity of preservatives consumed or on the
quantity of timber treated.
The application of the preservative may be carried out via vacuum processes, pressure processes,
dipping, spraying or brushing. The vacuum process may vary slightly, depending on the preservative
product. The application efficiency of the pesticide for dipping and brushing is close to 90% and using
the vacuum process with full containment is close to 100%. Spraying has a much lower efficiency, i.e.
from 5 – 50%.

According to the STS BREF [1], it is BAT to use a vacuum impregnation with water-based or high
concentration pesticide solvent systems or waste gas treatment such as activated carbon or
condensation. 99% reduction can be achieved using water-based systems and 70% with solvent-
based systems and waste gas treatment (about 15 to 25% of the solvent remains in the wood and
evaporate over the life of the product).
As a significant amount of solvent is released after the wood has been treated, it is BAT to use
solvents with lower ozone-forming potentials.
Techniques and corresponding associated emission factors defined in the table below originate from
the EGTEI background document [2].

for impregnation of wooden surfaces
emission levels for
VOC [2]
[Defined for the
following averaging
period:( yearly
average for total
AEL)]
3
All installations 100% of solvent based preservatives ~ 6 kg/m
vacuum impregnation system and waste gas wood treated
treatment such as activated carbon or
condensation* (adsorption on cartridges with
off-site recovery or disposal may also be
considered)
3
Process optimisation 11 kg/m wood
100% of more concentrated solvent based treated
preservatives
vacuum impregnation system
3
100% of water based preservatives ~ 0.2 kg/m
vacuum impregnation system wood treated
* According to the STS BREF [1], treatment of emissions is carried out in large installations when, in small plants,
abatement equipment may not be economically viable.

Costs and methodologies are defined in the EGTEI documents concerning “preservation of wood“ [2].
Abatement costs for primary measures vary from 0.3 to 0.7 k€/tonne of VOC abated and are even
negative in some particular cases. When secondary measures are implemented, abatement costs
vary from 1 to 21 k€/tonne of VOC abated depending on the size of the installation and on the
technique used.


[2] EGTEI background document/synopsis sheet: Wood preservation – 2004/2005

Mis en forme
7.38 Solvent content in products 2: Domestic uses of solvent (other than
paints)
7.38.1 Coverage
This source category covers the domestic application of glues, use of car care products, cleaning
agents, leather and furniture care products, pesticides, and cosmetics and pharmaceuticals.

VOC emissions are due to the solvents contained in the products. All solvents used are considered to
be 100% emitted into the atmosphere.

For the domestic use of organic solvents, emission reduction options are given only in terms of
substitution by zero or low organic solvent containing products (mainly water-based products), by non-
organic propellants, and the reduction of the packaging volume.
The BIPRO study aiming at identifying reductions in VOC emissions from the use of product [1]
defines maximum VOC content which could be mandatory in a list of products. 3 types of products are
considered: propellants, cosmetics (besides aerosols) and adhesives used outside installations (which
are already covered by the Directive 99/13/EC [2]). Maximum allowed VOC content are presented in
the table below.
The most important emission sources from the use of products containing VOC in the EU are [1] :
- aerosol in cosmetics (propellants) 180 kton/a
- solvents in cleaning products 110 kton/a
- solvents in adhesives 100 kton/a
Table 1: maximum allowed VOC content for each type of domestic products
Maximum allowed VOC ELV from the Californian

content [%] regulation [1], [3]
Propellants
Hair sprays 75 55
Deodorants 20 10
Antiperspirants 75 10 (MVOC), 40 (HVOC)
Cleaning Agents 10 4
Cosmetics (besides aerosols)
Skin care products 20
Shampoos, soap and bath products 3
Shaving products 3
Flagrances 80 75
Deodorants 20 10
Adhesives used in building and construction
a/
Roofing Solvent free
a/
Insulation Solvent free

Maximum allowed VOC ELV from the Californian

content [%] regulation [1], [3]
Ceiling titles 30
a/
Plywood paneling Solvent free
a/
Floor covering 8
Adhesives in woodworking and joinery
a/
Wood Solvent free
b/
Varnished surfaces No limitation
a/
Leather, textiles, felt 8
b/
Rubber, plastics, PVC 70
a/
Cushions and foams 8
Adhesives for footwear and leather
a/
Shoe upper assembly 10
Sole assembly 55
Sole fitting No limitation
Adhesives used by consumers, DIY
Wood Solvent free
Paper and board Solvent free
b/
Multipurpose and contact No limitation
adhesives
b/
Modelling and plastics 70
a/ exceptions for specific applications

b/ use of alternatives dependant on material and technical conditions
7.38.4 Cost data



[1] Screening study to identify reductions in VOC emissions due to the restrictions in the VOC conte nt
of products
[2] Directive 1999/13/EC of 11 March 1999. on the limitation of emissions of volatile organic
[3] Regulation for reducing VOC emissions from consumer products, Title 17, California Code of
Regulations, Division 3, Chapter 1, Subchapter 8.5, Article 2, Consumer Products, Sections 94507 -
94517 (dec. 2007).

7.39 Beer production

7.39.1 Coverage
Breweries with a production capacity of 300 tonnes finished product per day are covered by this
section on beer production. Here, the sector of beer production includes the malting stage, even
though these two process steps are carried out in different locations [1], [2].

Cereals used in the production of beer and some spirits are usually allowed to germinate before use.
This process is called malting, and results in the conversion of starch into sugars. Germinated cereals
may then be roasted. The length of roasting varies depending on the type of grain and the type of
beverage to be produced. Before fermentation, cereals are often boiled in water to produce wort,
which is then filtered to separate out the solid residues.
Fermentation occurs in large fermenting vessels and typically lasts one to three weeks. Normally,
vessels are sealed, recirculating the carbon dioxide. Others, normally in smaller plants, vent to
atmosphere via a water trap [3].

In order to reduce energy consumption, BAT for breweries is to reuse hot water from wort cooling,
recover heat from wort boiling and from condensing vapours (this also reduces odour emissions) to
preheat the next batch or process water. Where applicable, CO 2 should be recovered by cleaning,
compressing, drying and purifying it from the beer fermentation gas [1], [2], [4].
7.41.1.1 SO2
As a measure to reduce SO2 emissions, it is recommended to use commercially available low-sulphur

fuels [5].
However, SO2 emissions are not considered to be very significant for the sector of beer production
and are not discussed further; information on emissions from energy generation can be found in the
part on industrial boiler plants.
7.41.1.2 NOx
As a measure to reduce NOX emissions, the use of low NOX burners and regular maintenance of the
boiler is recommended [5].
However, these emissions are not considered to be very significant for the sector of beer production
part on industrial boiler plants.
7.41.1.3 Dust
If necessary, cyclones, fabric filters or electrostatic precipitators should be used on exhaust air to
remove particulates [3], [5].
However, these emissions are not considered to be very significant for the sector of beer production
1
part on small combustion plants [6] .
1 Mis en forme : Police :8 pt

According to the EMEP/Corinair guidebook 2006 : “These activities are not believed to be a significant source of PM2.5 (as of
December 2006) Mis en forme : Anglais (États Unis)

[comment: Corinair 2006 : “These activities are not believed to be a significant source of PM 2.5 (as of
December 2006)“]
7.41.1.4 VOC
Beer production is generally responsible for odorous emissions. Considerable emissions of VOCs can
be released from larger breweries, appropriate abatement techniques for odour and VOC should be
used and exhaust gases should be reused where possible. VOC emissions are partly controlled as a
result of odour reduction requirements and can be reduced by working in closed cycles , e.g. by CO2
recirculation. If the exhausted air from the brewhouse is condensed and the gas from fermentation is
recovered, there is no need for further emission abatement like biofiltration. If not, Biofiltration is a very
useful control measure and is particularly suitable for low VOC concentrations in the exhaust air and
for odorous emissions. Biofilters reduce odour and VOC emissions by absorbing the pollutants onto
the filter material and degrading them by the microorganisms located on the fixed filt er medium. They
are applicable for a wide range of airflows (up to >100000 m³/h), but airborne temperature may not
exceed 40°C. The investments and operating costs of biofiltration in this case are lower than those of
conventional control techniques (e.g. activated carbon adsorption). Alternatively, the organic odour
components can be removed by condensing the vapour from boiling vessels combined with energy
recovery.
VOC emissions generated by certain process steps may be reduced by applying control techniques
like condensation, activated carbon adsorption, or incineration. Selected applicable abatement options
and their respective achievable emission factors are given in Table 1 for beer production [1], [2], [4].
Table 1: VOC emission levels associated with BAT for beer production [2]

1
levels
Emission source 3 3 Comments
mg/Nm or (kg/tonne) kg/m
beer
Condensation of exhaust air
from the brewhouse and
recovery of fermentation gas or
Biofiltration of emissions from
Beer production (capacity > 3 the malting of grain and CO2
3 (0.004) [kg/m beer] [2] recovery during fermentation
1,000 m /year)
[comment: EMEP/Corinair
guidebook 2007 : 0.035 kg/hl
beer; no value given in BREF]
1

7.39.4 Emerging Technologies

No major technological breakthroughs are expected for this sector.
8 Table 2: cost data for CO2 recovery and biofiltration [1]
Operating
Characteristics of reference Investmentsa/ Abated mass flow
Control options costsb/
installation [EURO] [Mg VOC/year]
[EURO/year]
Beer production (malting included)
Large brewery; production

capacity: 150,000 m3/year beer; CO2 recovery during fermentation
operating time: and biofiltration of emissions from 250,000 3,2000 9
malting of grain
4,000 h/year
VP: vapour pressure.

a/ Depending on e.g. waste gas flow rate, VOC concentration in the waste gas, production capacity. Unless specified
otherwise, all investments mentioned represent additional investments if the technology switch occurs in the course of an
autonomous technology change.
b/ Depending on e.g. waste gas flow rate, VOC concentration in the waste gas, heat recovery rate.
Table 32: cost data for biofilters [1]
Installation size (airflow) Specific investment Operating cost
Small (200-500 m³/h) 45-50 €/m³
0.225-0.3 €/1000m³
(including 0.15-0.225 €/1000m³ energy cost,
Larger plants Down to 10-15 €/m³ calculated with electricity costs at 0.15 €/kWh)
Mis en forme : Hiérarchisation +

Niveau : 3 + Style de numérotation : 1,
2, 3, … + Commencer à : 6 +
Alignement : Gauche + Alignement :
1.51 cm + Retrait : 2.78 cm

1 European Commission. 2006: “Integrated Pollution Prevention and Control (IPPC) Reference
Document on Best Available Techniques in the Food, Drink and Milk Industries.”
2 Old version of the Gguidance document on control techniques for emissions of sulphur, NOx and
VOCs from stationary sources - 1999
3 Environmental Protection Agency Ireland. 2006: Draft BAT Guidance Note on Best Available
Techniques for the Brewing, Malting & Distilling Sector (Final draft)
4 IFC 2007. International Finance Corporation (World Bank Group): Environmental, Health, and Safety
Guidelines for Breweries
5 The Brewers of Europe 2006: Guidance Note for establishing BAT in the brewing industry
6 EMEP/CORINAIR Emission Inventory Guidebook (Activities 040606-040608), December 2006

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including PM10,
PM2,5 and black carbon) from stationary sources
7.41 New Stationary Engines

7.41.1 Coverage
The stationary engines sector covers combustion techniques of stationary engines using liquid or gaseous
fuels. This paper focuses mainly on reduction of nitrogen oxide emissions (NOx) from new stationary engines
with a rated thermal input of more than 1 MW th spark ignition (SG) or dual fuel (DF in gas mode) or more than
5 MW th diesel engines. Some information is also given on the effects of fuels and reduction of dust (including
PM10, PM2,5 and BC), carbon monoxide (CO) and volatile organic compound (VOCs) emissions from
stationary engines (definitions are provided in chapter 1, 5 and 6).

The combustion processes as a whole lead to the generation of emissions to air, which are considered to be
one of the major sources of air pollution. Depending on the type of the fuels and techniques available,
several technologies (such as boilers, gas turbines or stationary engine plants) are available which show
considerably different NOx, SOx and particulate matter emissions. This paragraph describes the main
stationary engine technologies used for the combustion of liquid and gaseous fuels.
Definitions for engines:

Stationary engines can be divided according to fuel used into (see Table 2);
diesel engines (inclusive dual fuel high pressure gas diesel (GD))
spark plug or by other device ignited gas engines (SG) and
dual fuel engines (low pressure gas DF).
Also, stationary engines can be divided into 2- and 4-stroke engines. :

2-stroke engines with compression or open chamber ignition and combustion are low speed engines
(<300 rpm) and can be either one or (high pressure gas) dual fuel (GD) solutions.
4-stroke engines are ignited with compression, pilot, spark or hot body principle, they have open
chamber, pre-chamber, lambda 1 or lean-burn combustion solutions and are either medium (300 < n
< 1200 rpm) or high speed (> 1200 rpm) engines. Different engine solutions are such as gas-fired
spark ignited (SG), dual fuel low pressure gas (DF) or high pressure gas diesels (GD) or liquid fired
diesel or DF engines.
Mis en forme : Retrait : Gauche :
Also, stationary engines can be divided according to their speed: 1.27 cm, Sans numérotation ni puces
the low-speed and medium-speed engines are often used in e.g. base load, decentralized
small/medium sized combined heat and power (CHP), gas compression and crude oil pumping and
grid peaking plant applications. Low and medium speed engines can operate either in one or dual
fuel principle.
low speed 2-stroke engines (available up to about 90 MW e unit sizes) operate on liquid distillate fuel
oil, HFO (heavy fuel oil), residual, emulsified fuel oil, refinery vacuum residuals and high pressure
natural gas (GD type).
medium speed 4-stroke engines (available up to about 25 MW e diesel engines), up to about 17 MW e
low pressure gas dual fuel (DF) and spark ignition (SG) up to about 10 MW e unit sizes) operate on
liquid distillate fuel oil and HFO (diesel and dual fuel engines), liquid residual fuel oil, emulsified fuel
oils, refinery vacuum residuals (diesel engines), natural gas (gas diesel (GD), dual fuel (DF) and
spark ignition (SG) types), biogas, mining and landfill gas (depending on SG and GD types).
high-speed engines are mostly used in peak load applications. High-speed stationary engine types
are usually small (unit size output up to a 5 MW e) and mostly operate on natural gas, biogas, landfill

Guidance document on control techniques for emissions of sulphur, NOx, VOCs and dust (including PM10,
PM2,5 and black carbon) from stationary sources
gas, liquid bio-fuels and liquid distillate fuel oil. High-speed engines are used both in electricity
production and in other non-road applications.
Table 1: main engine types according to fuels used
Compression ignition engines operate

according to a Diesel cycle whereby
air and fuel are injected separately
(not mixed) into the cylinder: air is
injected and compressed by a piston.
At the end of the compression stroke
fuel is injected, it ignites on contact
with the hot air. In gas mode high
pressure gas is used
Lean-burn gas engines operate

according to an Otto cycle, whereby
Gas fuel and burning air are premixed
engine, before injection into the cylinder. The
spark spark ignited lean burn engine is a
ignition “pure” gas engine and the gas fuel is
(by a spark ignited by e.g. a spark plug.
plug)
Dual fuel engines operate according

to a diesel cycle when firing liquid
fuels or, when used with gaseous
fuels, to an Otto cycle. In gas mode,
ignition is at the end of the
compression stroke via the injection of
a small amount of pilot liquid fuel. In
gas mode low pressure gas is used.

Table 2: current main types of stationary reciprocating engines
Typical classification of
Operating Ignition and Unit electric power
engines based on Mode of operation Fuels
principle combustion output
engine speed
One fuel operation Liquid distillate fuel (diesel oil),
Compression & HFO, residual, emulsified fuel
2-stroke Low speed (< 300 rpm) Dual fuel (GD) Up to 90 MW e
Open chamber oil, refinery vacuum residuals,
(high pressure natural gas) natural gas
One fuel operation
Ignition Liquid fuels, gas (Spark ignited Depending on engine type (see
type, SG) Chapter 2):
-Compression Up to
-Pilot Liquid distillate fuel (diesel oil),
Medium speed Dual fuel operation HFO, liquid residual fuel oil, - 25 MWe (diesel)
-Spark (300 – 1200 rpm) High pressure natural gas (Gas emulsified fuel oils, refinery - 17 MWe (DF)
-Hot body Diesel, GD) vacuum residuals, liquid
Low pressure natural gas (Dual biofuels - 10 MWe (SG)
4 –stroke Fuel, DF) Natural gas, biogas, landfill gas
Combustion
Back-up-mode: liquid fuel
-Open chamber
-Pre-chamber
One fuel operation Natural gas, biogas, landfill gas,
-Lambda 1 High speed
Liquid fuels, gas (Spark ignited liquid biofuels, liquid distillate Up to 5 MW e
-Lean-burn (> 1200 rpm) fuel oil (diesel oil),
type)

BAT for controlling NO x emissions from lean burn type gas engines
For gas-fired stationary engine plants, the lean-burn approach to reduce NO x emissions is BAT, it is
analogous to the dry low NOx technique used in gas turbines. This is a primary measure that requires
no extra reagents or water additions to achieve low NO x levels. For spark plug or by other device
3
ignited (SG) natural gas fired lean-burn engines, a NOx level of 95-190 mg/Nm at 15% O2 and 190-
3
380 mg/Nm at 15% O2 for low pressure gas dual fuel engines are achievable by primary measures.
Because gas engines can be equipped with a SCR this is also considered as BAT. For engines using
natural gas oxidation catalysts are BAT for CO emissions control. Fuel gas cleaning will be needed in
1
most cases when using oxidation and SCR catalysts when burning other gaseous fuels, such as
2
biogas or landfill gases, that might contain catalyst poisons . Engine optimization is a compromise
between NOx emissions, engine efficiency (fuel consumption and thus CO 2 emission) and other
emissions (such as CO and hydrocarbons). With the application of SCR (secondary measure) NOx
3 3
emissions levels in range of 5 -19 mg NOx /Nm in 15 % O2 have been measured.
BAT for controlling NO x emissions from liquid fuel-fired (diesel) engines

The application of primary methods and secondary measures, in particular the application of the SCR
system is regarded as BAT to reduce NO x emissions from liquid fired diesel engines. A limitation for
the applicability of SCR is given for diesel engines, which need to be operated in varying loads. SCR
is a commonly applied system for diesel engines but cannot be seen as BAT for engines with frequent
load variation due to technical constrains (see LCP BREF p. 406). A SCR unit would not function
effectively when the operating conditions and the consequent catalyst temperature are fluctuating
frequently outside the necessary effective temperature window. Achievable NOx emission levels for
operational diesel engines, using primary measures, have been found to range from 1460 to 2000 mg
3
NOx /Nm depending on the fuel and engine type. For new engines according to the new IFC/WB
3
Guidelines, depending on bore size, the range of the emission level is 1460 – 1850 NOx /Nm at 15 %
O2.
For diesel engines it is necessary to use SCR as a secondary measure to reach the emission limit
3 3
values of 190 or 225 mg NOx /Nm in 15 % O2 (equivalent to 500-600 mg NOx /Nm in 5 % O2 given in
the Gothenburg Protocol. It should be noted that, for engines with SCR, a minimum flue-gas
temperature (dependent on the fuel sulphur content) is needed to prevent salt formation clogging the
catalyst and that the supply infrastructure is in place to supply ammonia or urea of adequate quality.
Achievable NOx emission levels with SCR based on the examples of diesel engine plants in operation
3
range from 145 to 325 mg NO x/Nm with fuels from light to heavy fuel oils, respectively (EU LCP
BREF Table 6.23 and 6.12). It should be noted that the NO x-reduction of a SCR system is dependent
on the fed reagent amount (dependent on the exhaust gas flow and inlet NO x concentration/set outlet
NOx-limit). The control system will adjust the reagent flow to the SCR based on the feed-forward
signal from the engine loading (preprogrammed parameters during the commissioning of the plant
based on NOx measurements). In some cases also a feed-back signal (from a NOx-measurement
device) is used for “fine tuning” of the system besides the feed-forward signal. The set NOx-levels
various in different countries as the following examples show:
3
- in Belgium and in the Netherlands NO x emission values of 130 to 150 mg/Nm (15 % O2) for
new diesel engines have recently been introduced
3
- according to the German TA-LUFT 2002 the set NO x-limit is equivalent to 190 mg/Nm (15 %
3
O2) and the French NO x-limit is close to former TA-LUFT 1986 about 750 mg/Nm (15 % O2).
1 Only limited experience exists thus far

2 The catalysts might get deactivated. There is limited experience from SCR with the use of biogas at the moment and the systems are
expensive. Additional fuel gas purification equipment is necessary to clean out detrimental compounds such as e.g. NH3 and H2S.
3According to the industry, this NOx value can be reached under ideal conditions using a fresh new catalyst, but will not be met during
normal operation.
24 September 5 July 2012 Page 266

A Dual Fuel (DF) engine is not part of the current Protocol. A DF engine in liquid/back-up mode has
higher NOx emissions than a modern diesel engine due to the lower compression ratio, a DF engine is
optimized for natural gas mode operation.
The emission of NOx depends on the engine speed. Fuel efficient, large bore, low speed engines tend
to have higher NO x emissions than faster running smaller engines. When the engine speed is lower,
NOx concentrations are higher in the combustion chamber because of the longer residence time
during which to form NOx.
7.41.3 Options for reducing emissions from stationary engines
Options for reducing emissions to air from liquid fuel-fired (diesel) engines
The main pollutants emitted in the exhaust of a typical (compression ignition) diesel engine burning
heavy fuel oil include nitrogen oxides (NO x), particulate matter (PM) and sulphur oxides (SO x). SOx
and PM are mainly fuel related emissions. Due to the high efficiency resulting from the high
temperature of combustion in stationary diesel engines, emissions of unburned emissions such as
carbon monoxide and unburned hydrocarbons are low.
Abatement of dust (including PM10, PM2.5 and BC) emissions

When burning heavy fuel oil, dust mainly consists of the ash and sulphur (formed sulphates) contents
from the fuel oil and to a smaller extent of soot, BC and hydrocarbons. When burning light fuel oil, the
particulate matter mainly consists of soot, BC and hydrocarbons (HCs). BC emissions can be
4
estimated in the range 0.05 to 0.2 g/kg fuel with heavy fuel oil and steady state high load . Secondary
5
cleaning equipment for dust is currently being developed for larger diesel engines . Diesel particulates
form under very different conditions of excess oxygen and temperature compared to dust formed in a
boiler. The electrical properties (e.g. resistivity, etc.) differ from particulates from a boiler flue-gas, and
proper testing of the ESP (electrostatic precipitator) is needed prior to commercial release. The use of
engine measures in combination with the use of a low ash and low sulphur fuel, whenever
commercially available, can be considered as BAT for reducing dust emissions. Dust concentrations
(85 to 100 % of MCR engine load, measurement method ISO 9096 or principally similar other
3
measurement method) lower than 50 mg/Nm at 15 % O2 (after engine) can be achieved with heavy
fuel oil with S concentrations lower than 1.0 wt-%, ash concentration lower than 0.03 to 0.04 wt-%,
and asphalthene content lower than 8 wt-%. With heavy fuel oil of lower quality (higher sulphur, ash,
3
and asphalthenes contents) concentrations lower than 75 to 100 mg/Nm at 15 % O2 can typically be
achieved depending on used heavy fuel oil properties. (Remark: Diesel Particulate Filters (DPF) used
on heavy duty vehicles and small off road engines are not yet suitable for large stationary diesel
engines covered by the guidance document (larger > 5 MWth). Particulate traps are indeed used in
many diesel cars and trucks running on clean diesel fuel for filtering off partic ulates/soot. The trap has
to regenerate on a regular basis, i.e. the trapped soot must be burnt out. Precious metal catalysts are
often used for regeneration. Oxidation catalysts are sometimes used on clean distillate oil operated
diesels equipped with EGR for oxidation of CO, HC and soot. Both systems are based on precious
metal catalysts – fast deactivation and clogging would occur with power plant normal fuel qualities.
Particulate traps are therefore not yet suitable for large medium/slow speed engines designed to be
able to run on heavy fuel oils or other residual fuels. It could be possible for large diesel engines to
also run on alternative fuels like LFO).
4
CIMAC – The International Council on Combustion Engines – Background information on black carbon from large marine and stationary
diesel engines – definition, measurement methods, emission factors and abatement techniques -2012
5 LCP BREF 2006, page 356

Abatement of SO2 emissions

The sulphur oxide emissions are directly related to the used fuel and to the sulphur content of the fuel.
The primary method to reduce the SO x emissions is to use a low sulphur content liquid fuel or natural
gas if commercially available. Currently few diesel engine systems are equipped with DESOX
(desulphurization units) installations and, of these, most are small or medium sized plants and there is
little accumulated experience. Here too it should be noted that a diesel flue-gas differs from a boiler
flue-gas, for instance it has high oxygen content, which might adversely impact in the performance of
the DESOX system. The investment cost for a DESOx plant varies a lot according to the method
chosen. The operating cost mainly depends on the amount and type of reagent, water, electricity
consumption, and maintenance and waste-product disposal costs. The DESOx system needs proper
maintenance in order to work optimally.
Abatement of NOx emissions

In general, the application of primary methods including the use of better fuel quality to reduce air
emissions at source is preferred to secondary measures (end-of-pipe techniques), which is often also
costly. During the last decade, NO x emissions from liquid fuel-fired diesel engines have been reduced
considerably by primary measures as a result of extensive research and development work on the
engine, whilst maintaining its high efficiency. Nevertheless NOx emissions of diesel engines without
secondary measures are still considerable and further reduction needs to be worked on. Primary
measures that can be applied for liquid fuel-fired diesel engines, include a base engine optimized for
low NOx, fuel injection retards, and the addition of water (such as water injection directly into the
combustion space, water-in-fuel emulsion, or humidification of the combustion air). If natural gas is
available, an option (dependent on engine type, if possible) is to convert of the diesel engine to a low
pressure gas dual fuel engine (DF).
The applicable secondary method for diesel engines is the use of SCR (Selective Catalytic
Reduction).
Control of NOx emissions from liquid-fired (diesel) engines

Achievable NOx emissions for new heavy fuel oil (HFO) and light fuel oil (LFO) fired stationary
medium/low-speed diesel engines with primary dry abatement technique are according to the EU LCP
BAT BREF information and according to the new World Bank EHS guidelines 2008 (second
3
generation engines) today below 2000 mg/Nm (15% O2). Cost effective and technically suitable
primary and secondary exhaust gas cleaning technologies are the focus of today’s product
development. In general the application of primary methods to reduce air emissions at source is
preferred to abatement after formation from the exhaust gas, often at great expense.
Technical measures to reduce NOx emissions can be divided into primary and secondary abatement
techniques:
Primary methods for liquid fuel-fired diesel engines, such as a base engine optimized for low NO x
(using the Miller concept - a “dry method”), fuel injection retards, the addition of water (such as water
injection directly into the combustion space, water-in-fuel emulsion, or humidification of the
combustion air, water emulsion, etc. depending on the application and engine manufacturer). “Dry
methods” are preferred in those areas where there is limited access to suitable water supplies.
Mechanical, thermal loading and fuel consumption limitation, etc. aspects are factors to consider when
applying primary NO x reduction methods.
By using a low NOx combustion concept in combination with the Miller concept the NO x emissions of
modern engines is up to 40 % lower than that of a similar engine type from the beginning of 1990s
whilst maintaining the same, high, efficiency. The development work is continuing but the turbocharger
is the technical bottleneck; higher pressure ratios are needed in order to enhance the “Miller-concept”,
otherwise the fuel consumption will increase and power output of the engines might decrease. A new
generation of turbochargers is needed if lower NO x emissions are to be achieved.

Secondary method: the only applicable secondary method for diesel engines is exhaust gas treatment
with SCR (Selective Catalytic Reduction). SCR is an efficient NO x abatement technique in cases
where it is possible to take into account the following issues related to installation and operation
6
ensuring that the techniques works properly :
a minimum flue-gas temperature needs to be maintained, depending on the sulphur content of
the fuel;
some trace metals (such as Na, K, Ca, Mg, As, Se, P) might act as catalyst poisons
if heavy fuel oil or other residual fuels are used, a soot blowing system needs to be installed
in the SCR reactor to keep the elements clean and avoid pressure drop increases
regular maintenance and inspection in order to maintain low ammonia slips that are harmful
for components situated after the SCR reactor
disposal of used elements
supply of reagents (pure ammonia, aqueous ammonia or urea) needs to be ensured
(infrastructure exists)
installation, operation and maintenance costs to be covered
Achievable NOx emissions ranges for existing diesel engines with primary measures and secondary
measures are described in Table 3 (measurement results from selected references around the world,
note ambient relative humidity has a big impact on the resulting NO x emissions from a diesel engine).
As mentioned above the achievable NO X emissions for new diesel engines are now below 2000
mg/Nm³ in case of primary measures (WB EHS guidelines: 1460 - 1850 mg/Nm³ at 15 % O2),
depending on the bore size.
Table 3: examples of achievable NOx emissions with emission reduction measures for diesel
7
engines
NOx emissions (HFO)

Diesel engine type 3 Remarks
mg/Nm dry, 15 % O2
Standard diesel engine in
Base engine optimized for low NOx
2163 – 2178 production, until 2000 (plant in
(Primary)
the Caribbean)
Standard diesel engine in
Base engine optimized for low NOx
1739 – 1881 production today (plant in
(primary, second generation)
Central America)
Typically up to 10 to Fuel consumption increase
20 % NOx reduction depends on the degree of
Engine with injection retard
(depends on engine injection retard, typically up to 3
type) %
Used mostly in ships, fuel
Slow speed engine
1540 consumption increases, (plant in
+ ‘water addition’
the Caribbean)
Engine with SCR (Secondary 150 diesel oil
measure) 325 oil with 0,45 wt-% S
6
LCP BREF 2006, page 360
7
LCP BREF 2006, page 379

Impacts of fuel quality on the operation of diesel

For diesel engines, fuel quality has a central role on the emissions. The sulphur content of liquid fuels
(including HFO and gas oils etc.) alternates /varies typically from 0.1 or less to 4 wt-% S in the UNECE
Region Medium sized (up to about 25 MW e) and slow-speed engine types (up to about 90 MW e unit
size) usually operate on more economical fuel oils such as heavy fuel oils, fuel emulsions, refinery
vacuum residuals. Small high-speed engines (up to about 5 MW e unit size) are operating on distillate
oils (low sulphur diesel and ultra low sulphur diesel). Some types of diesel engine can also operate on
natural gas and bio-oils.
The fuel quality also has impact on the primary NO x abatement methods that can be used. In small
high speed applications e.g. EGR (Exhaust Gas Recirculation) and high pressure, electronically
controlled injection can be used and lower NO x levels achieved compared to the bigger engine types.
The “Miller concept” (early closing timing of the air inlet valves, which suppresses the in-cylinder
temperatures reducing NO x formation) and advanced fuel injection equipment are applicable to bigger
modern engine types.
Abatement of CO and hydrocarbon emissions from liquid fuelled (diesel) engines

8
Good engine maintenance is regarded as BAT for the minimization of unburned gaseous air pollutant
emissions, a well operated large diesel engine has low CO and hydrocarbon (HC) emissions. CO can
be reduced by primary measures aiming at complete combustion. The most important parameter
governing the rate of NO x formation in a diesel engine is the combustion temperature: the higher the
temperature the higher the NO x and lower the unburned emissions. There is an optimum balance
between the emissions: a lower NO x will lead to higher unburned emissions (see Figure 1) and vice
versa.
Reducing NOx emissions by primary measures may increase other emissions such as CO, CO 2 and
particulate matter as shown in Figure 1. Oxidation catalysts may be applied to abate emissions from
high speed light fuel oil fired engines but not for engines using heavy fuel oil.
8 according to the EU LCP BREF document

Figure 1: Typical emission trends for a diesel engine as a function of efficiency (cylinder
temperature)
CO
Control of NOx emissions from gas engines, spark-ignited (SG) and dual fuel (DF) (gas mode)
Spark, or otherwise, ignited 4-stroke lean-burn gas engines (SG) are “pure gas” engines, they operate
on low pressure natural gas and (depending on engine type) also biogases such as landfill, digester
and mine gases. Dual fuel (DF) engines are designed to operate in gas mode on low-pressure natural
gas as the main fuel.
By primary engine measures in natural gas mode following NO x emissions can be achieved: for lean-
3
burn SG engines 95-190 mg/Nm at 15% O2 and for low pressure gas dual fuel engines 190-380
3
mg/Nm at 15% O2. For other gases than natural gas levels of 95-190 mg/Nm³ can also be achieved
with lean burn SG engines, but possible fluctuations of gas composition and contaminations may have
to be considered when defining emission limit values.
The combustion temperature is the most important parameter governing the rate of NO x formation in
internal combustion engines: the higher the temperature the higher the NO x content of the exhaust
gases. One method to reduce the combustion temperature is to lower the fuel/air ratio, the same
specific heat quantity released by the combustion of the fuel is then used to heat up a larger ma ss of
exhaust gases, resulting in a lower maximum combustion temperature. This primary measure called
the lean-burn approach in gas-fired stationary engines is analogous to dry low-NOx combustors in gas
turbines. Gas fired stationary engine (SG and DF types) installations have low NO x levels due to the
lean-burn approach.
As the lean-burn engine operates in a leaner mode (enhanced lean-burn) at lower set NO x levels with
higher specific fuel consumption, the flue gas temperature gets colder and as a consequence the
useful heat energy in the flue gas decreases.
In some special applications stationary gas engines are equipped with SCR for additional NO x
9
reduction . The driving force for application of SCR is the need to improve local air quality. Strict NO x
9
In 2008 in the Netherlands there were about 1000 stationary gas engines using SCR (such as CHP production and CO2 fertilization in
greenhouses). However it should be noted that the feasible investment costs when comparing a power plant to a greenhouse gas
application differ considerably."

reduction targets are also needed for some countries with a polluted air-shed in order to meet the
obligations of international agreements or EU Directives. In Table 4 achievable NO x emission levels for
gas fired engines with reduction measures are given.
In some special applications stationary gas engines are equipped with SCR for additional NO x
reduction. The driving force for application of SCR is the need to improve local air quality. Strict NO x
reduction targets are also needed for come countries with a polluted air-shed in order to meet the
obligations of international agreements or EU directives. For instance, one country has taken action
3
for applying stricter NO x ELVs such as 35 mg/Nm for stationary engines with obligation of using SCR,
due to the need to take in use all possible reduction measures for different sectors in order to be able
to comply with the NO x ceiling of the Gothenburg Protocol.
Table 4: achievable NOx emissions for gas engines (at steady state engine load) according to
10
the EU LCP BREF Document
NOx emissions,
Engine type 3
Measure Remarks
mg/Nm (Dry, 15 % O2)
Normal rating - optimal specific fuel consumption

161-190
(primary) - minimum unburned emissions
- increase of specific fuel
Low-NOx tuned
71- 83 consumption (up to 3% higher) and
(primary)
unburned emissions
Spark ignited Driving force for implementation of
gas engines SCR for gas engines is mainly
11
5 -19 situations where local air quality
SCR standards requests a high reduction
(secondary) of NOx or ozone emissions, as a
result of operation in highly populated
areas or the contribution of several
industries or mobile sources.
Dual fuel engine

- increase of specific fuel
- gas mode 144-177 consumption and unburned
emissions
Dual fuel engine
1531-1751 LFO = light fuel oil (> 0.05 wt-% S)
- Back-up mode
Gas Diesel Natural gas main fuel, pilot fuel
1584 – 1612
- gas mode heavy fuel oil
Unburned emissions from lean burn gas engines

NMVOC emissions from SG and DF engines in gas mode depend on the composition of natural gas.
Secondary emission reduction techniques for NMVOC emissions might, in some cases, be needed
and an oxidation catalyst for simultaneous CO and NMVOC reduction can be applied. The oxidation
catalyst reduction efficiency of NMVOC is very dependent of the hydrocarbon composition in the flue
10
Tables 7.9 (p.438) and 7.26 (p.466)
11 This NOx value can be reached under ideal conditions using a new and fresh catalyst but will not be met during normal operation.

12
gas, especially ethane and propane species are difficult to reduce . CO values kept below 100
3 13
mg/Nm (15 % O2) are considered as BAT for gas-fired engine equipped with a new oxidation
catalyst.
3
Based on the information from the engine industry, emission levels around 100 mg/Nm , are only
applicable for gas engines (equipped with oxidation catalysts) burning natural gas and not for gas
engines burning renewable gases like landfill gas, biogas or purification gas. For them the CO
3 14
associated level should be at a level of 110 – 380 mg/Nm (15 % O2) in order to represent BAT , due
to technical reasons (fuel composition impact).
Increase in carbon emissions when decreasing NO x emissions

Engine optimization is a compromise between NO x emissions, engine efficiency (fuel consumption and
thus CO2 emission) and other emissions (such as CO and hydrocarbons). A reduction in NO x
emissions by primary measures will increase CO 2 emissions (fuel consumption) as well as "unburned"
emissions such as CO, HC, and may also finally lead to misfiring, which might eventually destroy the
engine. In operation on biogases, the impurities of the biogas might create deposits on the engine
internal components and will thus put restrictions on the achievable NOx level. See subheader 9 below
(spark ignition engine type). In special cases, such as in polluted urban areas, where SCR is
sometimes used to reduce NOx emissions the air-fuel ratio can be optimized for best fuel efficiency,
and thus also emissions of unburned substances can be reduced. Modern gas engines are knock
limited and therefore the potential for operating engines in a richer fuel mode for improved efficiency
(and higher NOx) and lower CO and HC emissions is limited as other boundary conditions such as
engine knock must be respected.
Loss of efficiency when decreasing NO x emissions
As the lean-burn engine operates in a leaner mode at lower set NO x levels with higher specific fuel
consumption, the flue gas temperature gets colder and as a consequence the useful heat energy in
15
the flue gas decreases (detrimental for e.g. steam production in a CHP plant) .
7.41.4 Costs of BAT
Installation and operation costs of SCR
SCR has a high initial purchase price and, depending on the quality of the fuel used the catalysts will
need to be replaced periodically – and used catalyst disposed of in a proper manner. In addition, SCR
requires good technical support including spare parts and expertise to operate and maintain. For
typical costs of SCR as a function of NO x reduction, see Figure 2. Note that the cost and availability of
reagent might vary from location to location.
12Field Experience and Laboratory Analysis of Oxidation Catalyst on Dual Fuel Fuel Engines”, by Shazam Williams; Mojghan Naseri; Joe
Aleixo; Kristoffer Sandelin, published May, 7, 2006
13 LCP BREF, page 480
14 subheader 3 in Table 7.36 of LCP BAT BREF
15
Due to deposits formed inside the combustion chamber of biogas (landfill gas, anaerobic fermenter gases) fired engines, NOx levels far
below 190 mg/Nm3 at 15% O2 can not be achieved over the operation life of the engine because of a drift of the emissions caused by
isolation effects and change in combustion chamber geometry (Annex 7).

Figure 2: typical costs of SCR as a function of NO x reduction rate, heavy fuel oil fired medium
speed diesel engine power plant, reagent handling not included. Urea 40% solution 200
euros/ton, aqueous 25% ammonia solution 225 euros/ton)
Installed Cost O&M Costs

7 MW Engine 17 MW Engine
Urea (solution) Ammonia
50
8
40
Euro / kWe
Euro / MWh
6
30
4
20
10 2
0 0
0 20 40 60 80 100 20 40 60 80 100
NOx abatement [ % ] NOx abatement [ % ]
Mis en forme : Numéros + Niveau : 1

+ Style de numérotation : 1, 2, 3, … +
Commencer à : 1 + Alignement :
Gauche + Alignement : 0.63 cm +
Retrait : 1.27 cm
7.41.5 References used for chapter 7.41 Mis en forme : Retrait : Gauche :
1.27 cm, Sans numérotation ni puces
“Protocol to the 1979 Convention on Long-Range Transboundary Air Pollution to Abate + Style de numérotation : 1, 2, 3, … +
Acidification, Eutrohication and Ground Level Ozone”, Euromot April 2003, available at: Commencer à : 1 + Alignement :
http://www.euromot.org/download/news/positions/stationary_engines/UNECE_CLRTAP_ABC Gauche + Alignement : 0.63 cm +
_Analysis_080403.pdf Retrait : 1.27 cm
available at: http://www.unece.org/env/lrtap/multi_h1.html Mis en forme : Retrait : Gauche :
1.27 cm
[1] Integrated Pollution Prevention and Control (IPPC) Reference Document on Best Available
Techniques for large Combustion Plants, July 2006, Code de champ modifié
Mis en forme
http://eippcb.jrc.ec.europa.eu/pages/FActivities.htm
[2] COUNCIL DIRECTIVE 1999/32/EC of 26 April 1999 relating to a reduction in the sulphur
content of certain liquid fuels and amending Directive 93/12/EEC Gauche + Alignement : 0.63 cm +
http://eur-lex.europa.eu/en/index Retrait : 1.27 cm
[3] Position Paper of the CIMAC WG5 Exhaust Gas Emissions Controls on “Prime Mover Mis en forme : Retrait : Gauche :
Technique Specific Emission Limits Need Stationary Reciprocating Engine Plant”, at 1.27 cm
http://www.cimac.com/workinggroups/Index1-working-groups-exhaustemission.htm Mis en forme : Numéros + Niveau : 1
[4] Field Experience and Laboratory Analysis of Oxidation Catalyst on Dual Fuel Engines. Commencer à : 1 + Alignement :
http://www.dclinc.com
Retrait : 1.27 cm
[5] Euromot Position Paper on the LCP BREF preparations, 2002 : Mis en forme : Retrait : Gauche :
1.27 cm
http://www.euromot.org/download/news/positions/stationary_engines/EIPPCB_BREF
_euromot_comment_may_02.pdf Mis en forme : Numéros + Niveau : 1
[6] CIMAC – The International Council on Combustion Engines – Background information on Commencer à : 1 + Alignement :
black carbon from large marine and stationary diesel engines – definition, measurement Gauche + Alignement : 0.63 cm +
methods, emission factors and abatement techniques – January 2012 Retrait : 1.27 cm
Mis en forme : Retrait : Gauche :
1.27 cm
Retrait : 1.27 cm

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Convention on Long-Range Transboundary Air Pollution

Guidance document on control techniques for emissions of

5 July24 September 2012 Page 2

List of abbreviations and acronyms

AEL Associated Emission Levels

5 July24 September 2012 Page 3

EGR Exhaust gas recirculation

5 July24 September 2012 Page 4

5 July24 September 2012 Page 5

Voluntary left blank

5 July24 September 2012 Page 6

2 Common general issues for the pollutants considered 1713

3 General issues for sulphur 1915

4 General issues for NOx 2420

5 General issues for VOCs 3127

5 July24 September 2012 Page 7

6.4 Primary measures 4541

7 Available techniques for different activities 5349

5 July24 September 2012 Page 8

7.30 Manufacturing of coatings, varnishes, inks and adhesives 221

5 July24 September 2012 Page 9

5 July24 September 2012 Page 10

5 July24 September 2012 Page 11

5 July24 September 2012 Page 12

5 July24 September 2012 Page 13

SO2 NOx Dust BC VOCs

7-1 Combustion installation < 1MW with domestic combustion

5 July24 September 2012 Page 14

SO2 NOx Dust BC VOCs

7-22 Production of organic chemicals (excluding fine organic

5 July24 September 2012 Page 15

5 July24 September 2012 Page 16

2 Common general issues for all the pollutants considered in this

2.2 Energy management, energy efficiency, energy mix

5 July24 September 2012 Page 17

Reference used for this chapter:

5 July24 September 2012 Page 18

3 General issues for sulphur

3.2 Sulphur content of fuels

Table 2: typical limit values applied for liquid fuels in the EU

Fuel Current sulphur content (% weight) EU directive

3.3 Fuel switching

3.4 Fuel cleaning

5 July24 September 2012 Page 19

3.5 Combustion Technologies

3.6 Secondary measures - Flue gas desulphurisation processes

5 July24 September 2012 Page 20

In regenerative processes, a regenerating agent is used to recover SO 2. The sodium sulphite

5 July24 September 2012 Page 21

3.7 Costs of reduction techniques of SO2

Costs of SO2 abatement techniques are developed in chapter 7.

3.8 By products and side effects

Abatement technique Positive side effect Negative side effect

5 July24 September 2012 Page 22

3.9 References used in chapter 3

5 July24 September 2012 Page 23

4 General issues for NOx

4.2 Fuel switching

4.3 Fuel cleaning