Industrial Chemistry: General Introduction to

Industrial Chemistry & the Chemical Industry

Dr. Md. Sajid Ghufran

April, 2021
Industrial Chemistry - I
 INTRODUCTION TO INDUSTRIAL CHEMISTRY

Contents to be covered:-

 Classical and industrial chemistry

 Classify the chemical industry in terms of scale, raw materials, end use
and value addition

 Distinguish between unit operations and unit processes

 Background
 The development of industrial chemistry started when a need to know how
various chemicals are produced in much more than the laboratory scale.

 Chemistry knowledge is applied to furnish the rapidly expanding chemical

industries with ‘’recipes’’ which is called chemical processes.

 Industrial chemistry keeps up with the progress in science and technology. It

incorporates other emerging disciplines such as
 biotechnology, microelectronics, pharmacology and material science.

 The discipline is also concerned with economics and the need to protect the
environment.
Classical and Industrial Chemistry
 Difference between Classical and Industrial Chemistry
Definition
Industrial chemistry is defined as the branch of chemistry which applies
physical and chemical procedures towards the transformation of natural
raw materials and their derivatives to products that are of benefit to
humanity.

Classical chemistry (organic, inorganic and physical chemistry) is very

essential for advancing the science of chemistry by discovering and reporting
new products, routes and techniques.

Industrial chemistry helps us to close the gap between classical chemistry

as it is practiced commercially.
 Scope of Industrial Chemistry
The scope of industrial chemistry therefore includes:

 The exploitation of materials and energy in appropriate scale

 Application of science and technology to enable humanity experience the

benefits of chemistry in areas such as

• Food production

• Health and hygiene

• Shelter

• Protection
Classification of Industries
 Classification of Industries
Industry is a general term that refers to all economic activities that deal with
production of goods and services. Goods and services are key words of industry.

 We can expect industry in general to include the following sectors:

• Manufacturing
• Agriculture
• Energy
• Transport
• Education
• Building and construction
• Trade
• Finance etc.
 Classification of the Manufacturing Industry
Manufacturing produces manufactured goods. This makes it distinct from other
sectors like agriculture which also produce goods. In manufacturing,
materials are transformed into other more valuable materials.

Manufacturing industry can be defined as follows:

• Manufacturing industry is a compartment of industry or economy
which is concerned with the production or making of goods out of raw
materials by means of a system of organized labour.

• Manufacturing industry can be classified into two major categories namely

 Heavy industry
 Light industry
 Classification of the Manufacturing Industry
Capital-intensive industries are classified as heavy while labour
intensive industries are classified as light industries.

 Light industries are easier to relocate than heavy industries

 Light industry require less capital investment to build than heavier industry.

 Using the above classification criteria, examples of heavy industries

include those that produce
 Industrial machinery

 Vehicles and

 Basic chemicals
 Classification of the Manufacturing Industry
 Other measures used to classify industries include the weight or volume of
products handled and weight per cost of production.

 For example the weight of steel produced per dollar is more than the weight
per dollar of a drug. In this case, steel industry is a heavy industry whereas
drug manufacture is a light industry.

 Both inorganic and organic chemical industry can be either heavy or light
industry.

 For example the pharmaceutical industry which is basically organic is

light industry. Petroleum refining is organic but heavy industry. Iron and
steel industry is inorganic and heavy industry.
 Manufacturing sub-sectors
The raw materials and the actual products manufactured are so
varied, different skills and technologies are needed in manufacturing.
Manufacturing is therefore divided into sub-sectors which typically deal
with category of goods such as the following:
 Food, beverages and tobacco
 Textiles, wearing apparel, leather goods
 Paper products, printing and publishing
 Chemical, petroleum, rubber and plastic products
 Non-metallic mineral products other than petroleum products
 Basic metal products, machines and equipment.
 Chemical Industry
The chemical industry can also be classified according to the type of main raw
materials used and/or type of principal products made.
 Industrial inorganic chemical industries

 Industrial organic chemical industries

Industrial inorganic chemical Industries extract inorganic chemical substances,

make composites of the same and also synthesize inorganic chemicals.

Light industrial organic chemical industries produce specialty chemicals which

include pharmaceuticals, dyes, pigments and paints, pesticides, soaps and
detergents, cosmetic products and miscellaneous products.

Heavy industrial organic chemical industries produce petroleum fuels,

polymers, petrochemicals and other synthetic materials, mostly from petroleum.
Structure of the Chemical Industry
 The Structure of the Global Chemical Industry
The structure of global chemical industry can be divided into following three
sections:

1) Commodity chemicals (Industrial chemicals)

2) Specialty chemicals

3) Fine chemicals
 The Structure of the Global Chemical Industry
1) Commodity chemicals (Industrial chemicals):
 The global chemical industry is founded on Basic Inorganic Chemicals
(BIC) and Basic Organic Chemicals (BOC) and their intermediates.

 Produced directly from natural resources or immediate derivatives of

natural resources.

 Produced in large quantities.

 Commodity chemicals are therefore defined as low-valued products

produced in large quantities mostly in continuous processes.

 They are of technical or general purpose grade.

 The Structure of the Global Chemical Industry
1) Commodity chemicals (Industrial chemicals):
 In the top ten BIC, almost all the time, sulphuric acid, nitrogen,
oxygen, ammonia, lime, sodium hydroxide, phosphoric acid and
chlorine dominate.

 The reason sulphuric acid is always number one is because it is used in

the manufacture of fertilizers, polymers, drugs, paints, detergents and
paper. It is also used in petroleum refining, metallurgy and in many other
processes. The top ranking of oxygen is due to its use in the steel industry.

 Ethylene and propylene are usually among the top ten BOC. They are
used in the production of many organic chemicals including polymers.
 The Structure of the Global Chemical Industry
2) Specialty chemicals:
 These are high value-added products produced in low volumes, used in
extremely low quantities and sold on the basis of a specific function.

 Judged by performance and efficiency.

 Enzymes and dyes are performance chemicals.

 Other examples includes:

 Medicinal chemicals, agrochemicals, pigments,
 Flavour and fragrances,
 Personal care products,
 Surfactants and adhesives.
 The Structure of the Global Chemical Industry
3) Fine chemicals:
 High value-added pure organic chemical substances produced in
relatively low volumes and sold on the basis of exact specifications of
purity rather than functional characteristics are known as fine chemicals.

 Purity is of vital importance in their formulation.

Therefore the global market share for each type is roughly as follows:

Commodities chemicals: 80%

Specialties chemicals: 18%

Fine chemicals: 2%
 Raw materials for the Chemical Industry
Since there would be no chemical industry without raw materials, the subject
of raw materials is due for discussion at this stage.
 All chemicals are derived from raw materials available in nature. The price
of chemicals depends on the availability of their raw materials.

 Major chemical industries have therefore developed around the most

plentiful raw materials. The natural environment is the source of raw
materials for the chemical industry.

Source of raw materials for the chemical industry

Raw materials from the atmosphere
 The atmosphere is the field above ground level. It is the source of air from
which six industrial gases namely N2, O2, Ne, Ar, Kr and Xe are manufactured.
 Raw materials for the Chemical Industry
Raw materials from the hydrosphere
 Seawater is a good source of sodium chloride, magnesium and bromine.

Raw materials from the lithosphere

 The vast majority of elements are obtained from the earth’s crust in the form
of mineral ores, carbon and hydrocarbons.
 Coal, natural gas and crude petroleum besides being energy sources are also
converted to thousands of chemicals.

Raw materials from the biosphere

 Vegetation and animals contribute raw materials to the agro-based industries.
Oils, fats, waxes, resins, sugar, natural fibres and leather are examples of
thousands of natural products.
Chemical Processes
 Chemical Processes
Every industrial process is designed to produce a desired products from a variety of
starting raw materials using energy through a succession of treatment steps integrated in
a rational fashion. The treatments steps are either physical or chemical in nature.

Energy is an input to or output in chemical processes.

The layout of a chemical process indicates areas where:
 Raw materials are pre-treated.
 Conversion takes place.
 Separation of products from by-products is carried out.
 Refining/purification of products takes place.
 Entry and exit points of services such as cooling water and steam.
 Units that make up a chemical process
 A chemical process consists of a combination of chemical reactions.

 The reactions involve namely synthesis, calcination, ion exchange,

electrolysis, oxidation, hydration and operations based on physical
phenomena which includes
 evaporation, crystallization, distillation and extraction.

 In short a chemical process is therefore any single processing unit or a

combination of processing units used for the conversion of raw materials
transforms into finished products through any combination of
 Physical treatment
 Chemical treatment
 Units that make up a chemical process
Unit Operations (Physical treatment)
 There are many types of chemical processes that make up the global chemical
industry. However, each may be broken down into a series of steps called unit
operations.

 Therefore Unit operations are the physical treatment steps employed in a

chemical processes to transform raw materials and products into required
forms.

 These are the physical treatment steps, which are required to:
 Put the raw materials in a form in which they can be reacted
chemically.
 Put the product in a form which is suitable for the market.
 Units that make up a chemical process
Examples of unit operations:
Agitation Dispersion Heat transfer
Atomization Distillation Humidification
Centrifuging Evaporation Mixing
Classification Filtration Pumping
Crushing Floatation Settling
Decanting Gas absorption Size reduction

 We can define unit operations as physical transformations.

 These transformation includes:

 Size reduction
 Size enlargement and
 Separation of mixtures
 Units that make up a chemical process
Size Reduction
 Size reduction refers to all the ways in which particles are cut or broken into smaller
pieces.

 The objective is to produce small particles from big ones for any of the following
reasons.
 To reduce chunks of raw materials to workable sizes e.g. crushing of mineral ore.

 To increase the reactivity of materials by increasing the surface area.

 To release valuable substances so that they can be separated from unwanted material.

 To reduce the bulk of fibrous materials for easier handling.

 To increase particles in number for the purpose of selling and to improve blending
efficiency of formulations, composites e.g. insecticides, dyes, paints.
 Units that make up a chemical process
Jaw Crusher
 When a solid is held between two planes
and pressure is applied on one plane, the
solid is fractured and breaks into
fragments when pressure is removed.

 The fragments formed are of different

sizes.

 An example of an industrial equipment

that is based on compression is a jaw
crusher. Schematic diagram of a jaw crusher
 Units that make up a chemical process
Ball Mill
 A ball mill is based on impact.
Impact is the breaking up of
material when it is hit by an
object moving at high speed.

 The product contain coarse and

fine particles.

 Suitable for dry or wet- milling

Schematic diagram of a ball mill
of various material in cement,
fertilizer and metallurgical
industries.
 Units that make up a chemical process
Unit Processes (Chemical treatment)

 Unit processes are the chemical transformations or conversions that are

performed in a process.

 Examples of unit processes:

Acylation Calcinations Dehydrogenation

Hydrolysis Alcoholysis Carboxylation

Alkylation Electrolysis Amination

Isomerization Oxidation Dehydration

Hydrogenation Pyrolysis Esterification

Fermentation Ammonolysis Aromatization

Water in the Chemical Industry
 Water in the Chemical Industry
 Water conditioning and waste-water treatment have long been essential functions.

 However, the importance of suitably preparing water for the chemical industry is
sometimes underemphasized.

 The chemical manufacturing processes consume large quantities of water ranging in

quality from untreated to deionized.

 Industrial waste waters present a complex and challenging problem to the chemical
engineer.

 The solution is specific with each industry (indeed, almost with each plant or factory),
a few general principles may be observed: reuse of waste waters, recovery of by-
products to lessen the expense of treatment, and pooling of wastes to distribute
pollution or to effect a saving in neutralization costs.
 Water in the Chemical Industry
 The purity and the quantity of available water are very important in the
location of a chemical plant.

 Both the surface and the ground water should be considered.

 The ground water is more suitable usually for cooling purposes because of its
uniformly low summer and winter temperature.

 But such water is generally harder, may cause scale, and hence may interfere
with heat transfer.
 Hardness of Water and dissolved solids
 Hardness is usually expressed in terms of the dissolved calcium and magnesium
salts calculated as calcium carbonate equivalent CaCO3.

 Water hardness may be divided into two classes: carbonate and non-carbonate,
also frequently known as temporary and permanent hardness of water.

 Temporary hardness can usually be greatly reduced by boiling.

 Permanent hardness requires the use of chemical agents.

 Carbonate or temporary hardness is caused by bicarbonates of lime and

magnesia.

 Non-carbonate or permanent hardness is due to the sulphates and chlorides of

lime and magnesia.
 Hardness of Water and dissolved solids
 In addition to hardness, there may also be present varying amounts of sodium
salts, silica, alumina, iron or manganese.

 The total dissolved solids may range from a few parts per million in snow
water to several thousand parts per million in water from mineral springs.

 Other water impurities that may be present are

 Suspended insoluble matter (classed usually as turbidity)
 Organic matter
 Color and
 Dissolved gases. Such gases are carbon dioxide (largely as bicarbonate), oxygen,
nitrogen, and in sulfur waters, hydrogen sulfide.
 Hardness of Water
 Hard water is water that contains cations with a charge of +2, especially Ca2+ and
Mg2+.

 These ions do not pose any health threat, but they can engage in reactions that
leave insoluble mineral deposits.

 These deposits can make hard water unsuitable for many uses, and so a variety of
means have been developed to "soften" hard water; i.e., remove the calcium and
magnesium ions.

Problems with hard water

 Mineral deposits are formed by ionic reactions resulting in the formation of an
insoluble precipitate. For example, when hard water is heated, Ca2+ ions react with
bicarbonate (HCO3–) ions to form insoluble calcium carbonate (CaCO3).
Ca2+ (aq) + 2HCO3– (aq)  CaCO3 (s) + H2O + CO2
 Hardness of Water
Ca2+ (aq) + 2HCO3– (aq)  CaCO3 (s) + H2O + CO2
 This precipitate, known as scale, coats the vessels in which the water is heated,
producing the mineral deposits.

 In small quantities, these deposits are not harmful, As these deposits build up,
however, they reduce the efficiency of heat transfer.

 More serious is the situation in which industrial-sized water boilers become coated
with scale: the cost in heat-transfer efficiency can have a dramatic effect on power
bill.

 Furthermore, scale can accumulate on the inside of appliances, such as

dishwashers, and pipes. As scale builds up, water flow is impeded, and hence
appliance parts and pipes must be replaced more often than if Ca2+ and Mg2+ ions
were not present in the water.
 Hardness of Water
Strategies to "Soften" Hard Water

 For large-scale municipal operations, a process known as the "lime-soda process" is

used to remove Ca2+ and Mg2+ from the water supply.

 Ion-exchange reactions, which result in the formation of an insoluble precipitate, are

the basis of this process.

 The water is treated with a combination of slaked lime, Ca(OH)2 and soda ash,
Na2CO3.

 Calcium precipitates as CaCO3 and magnesium precipitates as Mg(OH)2. These

solids can be collected, thus removing the scale-forming cations from the water
supply.
 Hardness of Water
Strategies to "Soften" Hard Water
 To see this process in more detail, let us consider the reaction for the precipitation of
Mg(OH)2.

 Ca(OH)2 of slaked lime is moderately soluble in water.

 Hence, it can dissociate in water to give one Ca2+ ion and two OH– ions for each unit
of Ca(OH)2 that dissolves.

 The OH– ions react with Mg2+ ions in the water to form the insoluble precipitate. The
Ca2+ ions are unaffected by this reaction, and so we do not include them in the net
ionic reaction.

 They are removed by the separate reaction with CO32– ions from the soda ash.
Mg2+ (aq) + 2OH– (aq)  Mg(OH)2 (s)
 Hardness of Water
Water treatment (softening) by Ion-exchange
 Water softeners typically use a different process, known as ion exchange.

 Ion-exchange devices consist of a bed of plastic (polymer) beads covalently

bound to anion groups, such as -COO–. The negative charge of these anions is
balanced by Na+ cations attached to them.

 When water containing Ca2+ and Mg2+ ions is passed through the ion
exchanger, the Ca2+ and Mg2+ ions are more attracted to the anion groups than
the Na+ ions. Hence, they replace the Na+ ions on the beads, and so the Na+
ions (which do not form scale) go into the water in their place.
 Hardness of Water
Water treatment (softening) by Ion-exchange
 When hard water passes through the
ion exchanger (right), the calcium ions
in the hard water get exchanged by the
sodium ions in the ion exchanger.

 The softened water, containing sodium

ions in place of calcium ions, can be
collected for household use.
Treatment of Water
 Treatment of water by sedimentation
Plain sedimentation
 Wastewater, after preliminary treatment, undergoes sedimentation by gravity
in a basin or tank sized to produce near quiescent conditions.

 In this facility, settleable solids and most suspended solids settle to the bottom
of the basin.

 In the next step, mechanical collectors is provided to continuously sweep the

sludge to a tank where it is removed for further treatment and disposal
followed by the use of skimming equipment to remove those floatable
substances such as scum, oils, and greases which accumulate at the liquid
surface.
 Treatment of water by sedimentation
Chemical Sedimentation
 Sedimentation using chemical coagulation has been implied mainly to pre-
treatment of industrial or process wastewaters and removal of phosphorus from
domestic wastewaters.

 Chemicals commonly used, either singularly or in combination, are the salts of

iron and aluminium, lime, and synthetic organic polyelectrolytes.

 It is desirable to run pilot studies to determine the optimal chemicals and dosage
levels.

 The use of a given chemical(s) and effluent quality must be carefully balanced
against the amount of additional sludge produced in the sedimentation step.
 Filtration and membrane filtration
The newly emerging application of wastewater reuse is hyped to become the
most promising process for membranes in the water industry.

Membranes have been used in water and wastewater applications since the
1960's.

There are two classes of membrane process used in the water and wastewater
field:

 The first category includes Reverse Osmosis (RO) and Nano Filtration (NF).

 These membranes have a dense non porous separating layer cast onto a porous
support, and are used for the removal of dissolved substances.
 Filtration and membrane filtration
 The second category is membrane filtration. Membrane filtration process is a
physical separation method characterized by the ability to separate
molecules of different sizes and characteristics.

 In membrane filtration a micro-porous separating layer provides a barrier to

the finest particles present in the feed source but allows dissolved components
to pass through.

 One of the longest established uses for membranes in water treatment is in the
use of reverse osmosis (RO) for desalinating seawater.

 RO has recently taken over from distillation processes as the preferred

technology.
 Filtration and membrane filtration
There are two types of membrane filtration technology for water and
wastewater treatment.

 The two types include:

 Ultrafiltration (UF)

 Microfiltration (MF)

 Ultrafiltration (UF) has pores size of of 0.01 – 0.02 μm, while

Microfiltration (MF) for water treatment has pores size of 0.04 – 0.10 μm.

 In wastewater applications, coarser MF pore sizes of 0.2 and 0.4 μm can be

used, but the finer MF membranes for water duties are also suitable.
 Filtration and membrane filtration
 Microfiltration (MF) removes common particles found in water including
bacteria and other microbial organisms.

 Ultrafiltration (UF) removes viruses in addition, thereby providing a physical

disinfection barrier.

 For RO pre-treatment of wastewater, membrane filtration is normally used in

combination with coagulation to control fouling, ensure operational stability
and improve removals of dissolved organics.
 Filtration and membrane filtration

Ranges of membrane based separations

Hydrochloric acid (HCl)
 Hydrochloric acid or Muriatic acid
Hydrochloric acid (HCl)
Methods of Manufacture and uses
 Hydrochloric acid, although not manufactured in such large quantities as
sulfuric acid, is an important heavy chemical.

 Manufacturing techniques have changed and improved in recent years and new
procedures are employed such as the burning of chlorine in hydrogen.

 Hydrogen chloride, HCl, is a gas at ordinary temperatures and pressures.

 Aqueous solutions of it are known as hydrochloric acid or, if the hydrogen

chloride in solution is of the commercial grade, as muriatic acid.
 Hydrochloric acid or Muriatic acid
Hydrochloric acid (HCl)
 Hydrochloric acid is prepared by dissolving hydrogen chloride in water.

 Hydrogen chloride can be generated in many ways, and thus several precursors
to hydrochloric acid exist.

 The large-scale production of hydrochloric acid is almost always integrated

with the industrial scale production of other chemicals.

Historical perspective
 Hydrogen 'chloride was discovered in the' fifteenth century by Basilius
Valentinius.
 Hydrochloric acid or Muriatic acid
Hydrochloric acid (HCl)
 Commercial production of hydrochloric acid began in England when
legislation was passed prohibiting the indiscriminate discharge of hydrogen
chloride into the atmosphere.

 This legislation forced manufacturers, using the LeBlanc process for soda ash,
to absorb the waste hydrogen chloride in water.

 As more uses for hydrochloric acid were discovered, plants were built solely
for its production.

 The largest users of hydrochloric acid are the petroleum, chemical, food and
metal industries.
 Hydrochloric acid or Muriatic acid
Hydrochloric acid (HCl)
 Industry experts estimate that activation of oil wells consumes about 30
percent of the acid sold.

Breakdown of the remaining uses in percent is:

 Chemical production, 23 percent; Metal production, 13 per cent;

 Food industry including the production of monosodium glutamate and

starch hydrolysis, 12 percent;

 Metal and general cleaning, 10 percent; and miscellaneous uses, 13

percent.
 Manufacturing of Hydrochloric acid
Hydrochloric acid (HCl)
Manufacture:
Hydrochloric acid is obtained from four major sources:
 As a by-product in the chlorination of both aromatic and aliphatic hydrocarbons

 From reacting salt and sulfuric acid.

 From the combustion of hydrogen and chlorine.

 From Hargreaves-type operations (4NaCl + 2SO2 + O2 + 2H2O = 2Na2SO4 + 4HCl)

 The old salt-sulfuric acid method and the newer combustion method each supply
about 20 per cent. The Hargreaves process is used by only one company, although a
modified Hargreaves process is in operation at another plant.
 Reactions and Energy Requirements
Reactions and Energy Requirements
 The basic steps in the production of by-product acid include the removal of
any unchlorinated hydrocarbon followed by the absorption of the HCl in water.
A typical chlorination for illustration follows:
C6H6 + Cl2 → C6H5Cl + HCl
 Since the chlorination of aliphatic and aromatic hydrocarbons evolves large
amounts of heat, special equipment is necessary for control of the temperature
of reaction.
 The reactions of the salt-sulfuric acid process are endothermic.
NaCl + H2SO4 → HCl + NaHSO4
NaCl + NaHSO4 → HCl + Na2SO4
Summation:
2NaCl (s) + H2SO4 (l) → 2HCl (g) + Na2SO4 (s); ∆H = + 15.8KCal
 Reactions and Energy Requirements
Reactions and Energy Requirements
 The first reaction goes to completion at relatively low temperatures while the
second approaches completion only at elevated temperatures.

 The reactions are forced to the right by the escape of the hydrogen chloride
from the reaction mass.

 The reaction between hydrogen and chlorine is highly exothermic and goes
spontaneously to completion as soon as it is initiated
 Salt Process for Hydrochloric acid Manufacturing
Salt process:
The salt process may be divided into the following unit operations (Op.) and
unit processes (Pr.):
 Sulfuric acid and salt are roasted in a furnace to form hydrogen chloride
and sodium sulfate (salt cake) (Pr.).

 The hot hydrogen chloride, contaminated with droplets of sulfuric acid and
particles of salt cake, is cooled by passing it through a series of S-shaped
Karbate coolers, cooled externally by water (Op.).

 The cooled gas is then passed upward through a coke tower to remove
suspended foreign materials (Op.).
 Salt Process for Hydrochloric acid Manufacturing
Salt process continued…
 Purified hydrogen chloride from the top of the coke tower is absorbed in
water in a tantalum or Karbate absorber (Op.).

 Finished hydrochloric acid is withdrawn from the bottom of the absorber,

and any undissolved gas passing out the top of the absorber is scrubbed out
with water in a packed tower (Op.).
 The most important of the salt furnaces in operation is the Mannheim
furnace. This consists of a cast-iron muffle, composed of a dish-shaped top
and bottom bolted together and equipped with plows to agitate the reaction
mixture.

 The rotary furnace is growing in usage. Here sulfuric acid and salt are
continuously mixed and heated.
 Synthetic Process for Hydrochloric acid Manufacturing
Synthetic process:
 The synthetic process generates hydrogen chloride by burning chlorine
in a few percent excess of hydrogen.

 The purity of the ensuing acid is dependent upon the purity of the
hydrogen and chlorine.

 Both of these gases (hydrogen and chlorine) are available in a very pure
state as by-products of the electrolytic process for caustic soda, this
synthetic method produces the purest hydrogen chloride of all the
processes.

 The cooling and absorption are very similar to that employed in the salt
process.
 Handling of Hydrochloric acid
Handling:
Hydrochloric acid is extremely corrosive to most of the common metals and
great care should be taken.

 Hydrochloric acid is produced in solutions up to 38% HCl (concentrated

grade).

 Higher concentrations up to just over 40% are chemically possible, but the
evaporation rate is then so high that storage and handling require extra
precautions, such as pressurization and cooling.

 Bulk industrial-grade is therefore 30% to 35%, optimized to balance

transport efficiency and product loss through evaporation.
 Hydrochloric acid or Muriatic acid
Applications or uses
Hydrochloric acid is a strong inorganic acid that is used in many industrial
processes such as refining metal. The application often determines the required
product quality.

1. Pickling of steel (metal surface treatment used to remove impurities)

 One of the most important applications of hydrochloric acid is in the
pickling of steel, to remove rust or iron oxide scale from iron or steel
before subsequent processing, such as extrusion, rolling, galvanizing, and
other techniques.

 Technical quality HCl at typically 18% concentration is the most

commonly used pickling agent for the pickling of carbon steel grades.
 Hydrochloric acid or Muriatic acid
Applications or uses
2. Production of organic compounds:
 Another major use of hydrochloric acid is in the production of organic
compounds, such as vinyl chloride and dichloroethane for PVC.

3. Production of inorganic compounds

 Numerous products can be produced with hydrochloric acid in normal acid-
base reactions, resulting in inorganic compounds.

 These include water treatment chemicals such as iron (III) chloride and
polyaluminium chloride (PAC).
 Hydrochloric acid or Muriatic acid
4. pH control and neutralization
 Hydrochloric acid can be used to regulate the acidity (pH) of solutions.

 In industry demanding purity (food, pharmaceutical, drinking water), high-quality

hydrochloric acid is used to control the pH of process water streams. In less-
demanding industry, technical quality hydrochloric acid suffices for neutralizing
waste streams and swimming pool pH control.

5. Regeneration of ion exchangers

 High-quality hydrochloric acid is used in the regeneration of ion exchange resins.
Cation exchange is widely used to remove ions such as Na+ and Ca2+ from aqueous
solutions, producing demineralized water. The acid is used to rinse the cations from
the resins. Na+ is replaced with H+ and Ca2+ with 2 H+.
 Ion exchangers and demineralized water are used in all chemical industries, drinking
water production, and many food industries.
Hydrofluoric acid (HF)
 Fluorine and Fluoro-Chemicals
Fluorine
Introduction
 Fluorine, a pale, greenish-yellow gas of the halogen family, is the most
chemically active non-metal element. It occurs in the combined form and
second only to chlorine in abundance among the halogens.

 Fluorine was discovered by Scheele in 1771, but not isolated until 1886 by H.
Moissan after a period of more than 75 years of intensive effort by many
experimenters.

 The Freon refrigerants developed in 1930 fostered the commercial

development of anhydrous hydrofluoric acid (HF) and stimulated the growth of
this new industry.
 Fluorine and Fluoro-Chemicals
Fluorine
Uses
 The largest production of fluorine compounds is of hydrofluoric acid
(anhydrous and aqueous), used in making "alkylate" for gasoline manufacture
and Freon for refrigerants and Aerosol bombs.

 It is also employed in the preparation of inorganic fluorides, elemental

fluorine, and many organic fluorine- and non-fluorine-containing
compounds.

 Aqueous hydrofluoric acid (HF) is used in the glass, metal and petroleum
industries, besides in the manufacture of many inorganic and acid fluorides.
 Manufacturing of Hydrofluoric acid (HF)
Hydrofluoric acid (HF)
 Both aqueous and anhydrous hydrofluoric acid are prepared in heated kilns by
the following reaction:
CaF2 (fluorspar) + H2SO4 → CaSO4 + 2HF
 Aqueous acid is the older product and is formed by adsorbing the HF gases in
lead cooling and absorbing towers.

 By recycling absorption liquors, various strengths of acid are obtained,

although the most common strengths are 60 and 65 per cent.

 Since concentrations of 60 per cent and above can be handled in steel

compared with lead and hard rubber for lower acid strengths, the shipping
trend is more to the stronger or anhydrous acid.
 Manufacturing of Hydrofluoric acid (HF)
Hydrofluoric acid (HF)
 For anhydrous hydrofluoric acid (HF), finely ground fluorite is mixed with a
slight excess of sulfuric acid in a hopper and fed into a heated kiln (300 to 800
⁰C).

 A large vent pipe conducts the hydrofluoric acid (HF) and other gaseous
products counter currently into sulfuric acid absorption towers for
dehydration.

 After distillation, the hydrofluoric acid (HF) is condensed to a liquid by

refrigeration.
Sulphuric acid (H2SO4)
 Manufacturing of Sulphuric acid
Sulphuric acid (H2SO4)
Introduction
 During the 19th century, the German chemist Baron Justus von Liebig
discovered that sulphuric acid, when added to the soil, increased the amount of
soil phosphorus available to plants.

 This discovery gave rise to an increase in the commercial production of

sulphuric acid and led to improved methods of manufacture.

Uses
Sulphuric acid is the most widely used chemical.
 The largest single use of sulphuric acid is for making phosphate and
ammonium sulphate fertilizers.
 Manufacturing of Sulphuric acid
Sulphuric acid (H2SO4)
Other uses include
 Production of phosphoric acid.

 Trisodium phosphates for detergent making.

 Sulphuric acid is also used in large quantities in iron and steel making as a
pickling agent to remove oxidation, rust and scale from the metals.

 It is an oxidizing and dehydrating agent.

 Its dehydrating action is vital in absorbing water formed in chemical

conversions such as nitration, sulphonation and esterification. It vigorously
removes water and therefore it is being used in wood, cotton, sugar, and paper
industry.
 Manufacturing of Sulphuric acid
 As a strong oxidizing agent it is capable of dissolving such relatively
unreactive metals as copper, mercury and lead to make compounds of these
metals.

 It is used in the manufacture of aluminium sulphate for application in paper

pulp production and in water treatment.

 It is also used as an electrolyte in lead acid batteries found in cars.

 Manufacturing of Sulphuric acid
Various concentrations of sulphuric acid are available depending on the
application purpose. These includes:
 10% dilute acid for laboratory use, pH = 1

 33.3% for lead acid batteries, pH = 0.5

 62.2% for chamber and fertilizer manufacture, pH = 0.4

 93.2% Oil of Vitriol

 98% concentrated acid, pH = 0.1

 20% fuming sulphuric acid or oleum (104.5% H2SO4)

 Raw Materials and Manufacturing Process
Raw Materials
Raw materials for sulphuric acid are those that produce sulphur dioxide when
reacted with oxygen. The commonly used raw materials are:
 Elemental sulphur

 Sulphides such as pyrites

 Hydrogen sulphide from petroleum refineries

Manufacturing process
 Two processes, the lead-chamber and contact processes, are used for the
production of sulphuric acid.

 In their initial steps, both processes require the use of sulphur dioxide.
 Raw Materials and Manufacturing Process
Lead-chamber process
 This process employs as reaction vessels large lead-sheathed brick towers.

 In these towers, sulphur-dioxide gas, air, steam and oxides of nitrogen react to
yield sulphuric acid as fine droplets that fall to the bottom of the chamber.

 Almost all the nitrogen oxides are recovered from the outflowing gas and are brought
back to the chamber to be used again. Sulphuric acid produced in this way is only
about 62 to 70 percent H2SO4, the rest is water.

The Lead chamber process has become obsolete and has been replaced by the contact
process due to the following reasons:

 An increased demand for strong, pure acid and oleum

 Contact process plants are cheaper and more compact
 Manufacturing Process
Contact Process
 The second method of manufacturing sulphuric acid is the contact process,
which came into commercial use about 1900 century.

 This process depends on oxidation of sulphur dioxide (SO2) to sulphur

trioxide (SO3), under the accelerating influence of a catalyst.

 The first plants for contact process (before 1920) were built using platinum
catalysts.

 Finely divided platinum, the most effective catalyst, has two disadvantages:
it is very expensive, and it is deactivated by certain impurities in ordinary
sulphur dioxide. They include compounds of arsenic, antimony and lead.
 Manufacturing Process
Contact Process
 In the middle of 1920s, vanadium catalysts started being used and have since
then replaced platinum.

 By 1930, the contact process could compete with the chamber process and
because it produces high strength acid, it has almost replaced the chamber
process.
 Flow Chart for Manufacturing of Sulphuric acid

Fig: The flow diagram for sulphuric acid manufacture by the contact process.
 Main Steps Involved in Contact Process
Main steps in the plant of contact process are:
 Production of sulphur dioxide gas

 Purifying and cooling of the gas

 Conversion of SO2 into sulphur trioxide (SO3) by passing it through a

converter containing the catalyst

 Absorbing the sulphur trioxide in sulphuric acid

 Main Steps Involved in Contact Process
Production of SO3
Sulphur is burned in the sulphur burner to produce sulphur dioxide:
 Before combustion, sulphur, is first melted by heating it to 135°C. Combustion
is carried out at between 900 and 1800°C.

 The combustion unit has a process gas cooler. The SO2 content of the
combustion gases is generally around 18% by volume and the O2 content is
low but higher than 3%.

 The gases are generally diluted to 9-12% SO2 before entering the conversion
process.
S (s) + O2 (g) = SO2 (g), ∆H = -298.3 kJ at 25 ⁰C
 Main Steps Involved in Contact Process
Conversion of SO2 into SO3
The design and operation of sulphuric acid plants are focused on the following gas phase
chemical reaction in the presence of a catalyst:
2SO2 (g) + O2 (g) = 2SO3 (g), ∆H = -98.3 kJ at 25 ⁰C

From thermodynamic and stoichiometric considerations, the following methods are available
to maximise the formation of SO3 for the O2/SO2/SO3 system:
 Heat removal: the formation of SO3 is exothermic, so a decrease of temperature will be
favourable
 Increased oxygen concentration
 Removal of SO3
 Raising the system pressure
 Catalyst selection to reduce the working temperature
 Longer reaction time
 Main Steps Involved in Contact Process
Conditions employed for the conversion of SO2 into SO3
 This reaction is a reversible reaction and the conditions used are a
compromise between equilibrium and rate considerations.

 It is necessary to shift the position of the equilibrium as far as possible to the right in
order to produce the maximum possible amount of sulphur trioxide in the equilibrium
mixture.

 Even though excess O2 would move the SO2 formation to the right, the 1:1 mixture
gives the best possible overall yield of sulphur trioxide (SO3).

 The forward reaction is exothermic and is favoured by low temperature. However,

too low temperature slows the reaction. To get the gases to reach equilibrium within a
very short time, a compromise temperature of 400 – 450 ⁰C is used.
 Main Steps Involved in Contact Process
Conditions employed for the conversion of SO2 into SO3

 According to Le Chatelier’s principle high pressures favour the forward

reaction. However, even at relatively low pressures of 1 to 2 atmospheres,
there is a 99.5% conversion of sulphur dioxide into sulphur trioxide.

 In the absence of a catalyst the reaction is quite slow and is therefore carried
out in the presence of a vanadium oxide catalyst which has a long life because
it is not easily poisoned. Further more, vanadium catalyst has high conversion
efficiency.

 Its only disadvantage is that it requires use of low sulphur dioxide

concentration which makes plant capital cost to be high.
 Main Steps Involved in Contact Process
In summary, optimum conditions for sulphuric acid production in the contact
process are:
 A temperature of about 430 ⁰C
 A pressure of 2 atmospheres
 Vanadium pentoxide to be used as catalyst

Fig: Typical diagram of the converter and the multistage reactor for the conversion of SO2 into SO3.
 Main Steps Involved in Contact Process
Absorption of SO3
 Sulphuric acid (H2SO4) is obtained from the absorption of SO3 into sulphuric
acid with a concentration of at least 98%, followed by the adjustment of the
strength by the controlled addition of water.
SO3 (g) + H2O (l) = H2SO4 (l), ∆H = -130.4 kJ at 25 ⁰C

 SO3 will react with water to form sulphuric acid (H2SO4). However,
converting the sulphur trioxide into sulphuric acid cannot be done by simply
adding water to the sulphur trioxide (SO3).

 Direct mixing of SO3 with water by the above reaction is uncontrollable. The
exothermic nature of the reaction generates a fog or mist of sulphuric acid,
which is more difficult to work with than a liquid.
 Main Steps Involved in Contact Process
Absorption of SO3
 Instead, the sulphur trioxide is first dissolved in concentrated (98%) sulphuric acid to
form a product known as fuming sulphuric acid or oleum.
SO3 (g) + H2SO4 (l) = H2S2O7 (l)
 The oleum can then be reacted safely with water to produce concentrated sulphuric
acid.
H2S2O7 (l) + H2O (l) = 2H2SO4 (l)
Environmental issues
 Sulphuric acid is a constituent of acid rain, formed by atmospheric
oxidation of sulphur dioxide in the presence of water.
 Sulphur dioxide is released when fuels containing sulphur such as oil and coal are
burned. The gas escapes into the atmosphere forming sulphuric acid. Sulphuric
acid is also formed naturally by oxidation of sulphide ores.
Thank You