Cmi - The View of The HRSG.

Repowering Older Plants - The HRSG View
International Conference Power Plants 2012

Society of Thermal Engineers of Serbia
Oct 30th Nov 2nd , 2012

Zlatibor, Serbia
Heat Recovery Steam Generators offered by CMI
Power Plants 2012- 2 of 32
Inherent features Horizontal & Vertical HRSGs
Horizontal
Vertical
Accessibility / Maintainability
Cleanability
Duct firing
Arrangement
Catalysts
Erection cranes
Cycling
Lets review the specific application of repowering power plants

and fuel oil in the following presentation slides
Introduction to power plants repowering

In the Balkan and Central Europe, there is a large fleet of old
coal fired power plants with a potential for repowering into
modern combined cycle power plants.
Compared to green field projects, repowering a steam turbine
with a new train of gas turbine and HRSG includes some special
challenges.
Most of the time, the HRSGs have to be tailored made to suit
limited foot print, and existing repowered steam turbine.
CMI has completed such a large repowering project, like
Senoko in Asia or Dunamenti in Hungary. These experience will
be the support throughout this presentation to explain these
specific repowering challenges.
Besides this main topic, CMI will present the HRSG for heavy
oil application, and the most recent references in Central
Europe.
Concept of Plant Repowering

OPTION
REMAIN
12
11
Condenseur
10
8
Turbine vapeur
6
13
HRSG
NEW
1 : condensats - 2 : eau alimentaire - 3: eau alimentaire. IP - 4: eau alimentaire HP

5: vapeur HP - 6: retour turbine (Cold reheat) - 7: resurchauffe - 8 : vapeur LP -
Pompes alimentaires
9: eau dsurchauffe by-pass IP - 10: by-pass IP - 11- by-pass LP

12: eau dsurchauffe by-pass LP - 13 : by-pass HP
Repowering Senoko - Project background

Repowering of old 3*120MW steam turbine into efficient CCPP
Main contractor was Alstom using its gas turbine engine GT26B
CMI Vertical HRSG 3P+R in natural circulation
HRSG tailor designed to suit numerous constraints
Project challenges:
- limited foot print of old boiler
- existing site very congested
- only 18 months outage
ALSTOM GT26 arrival at site

Site limitations
3D model
new boiler
Original fired boiler had to

contain new GT+ HRSG.
Available area for HRSG
was limited to 30.6*28.1m
HRSG indoor includes main
auxiliaries (cargo lift, FWP,
feedwater tank, etc)
CMI exchanged with
Alstom 3D model to make
detailed plant modelling
Vertical HRSG flexible layout

A Vertical HRSG behind GT class F for greenfield is around 35
meters long. In case of Vertical HRSG, tubes length impact directly
the overall boiler length. This is not the case for Horizontal HRSGs.
This is a special flexibility feature offered by the Vertical HRSG only.
Typical tubes length 20.4 m
Typical
heigth
9m
GT
Overall boiler length 35 meters

Vertical HRSG flexibility layout

To match this repowering limited space (length 30,6 meters), CMI has
taken advantage of this flexible arrangement offered by the Vertical
HRSG:
CMI used shorter tubes length. For unchanged casing cross section,
boiler casing was enlarged in proportion
Reduced
tube/boiler
length
Longest
tube
20.4 m
Gas cross section
Flexible
Gas cross
section
unchanged
Slightly
enlarged
boiler
width
Vertical HRSG flexibility layout

Considering the installed boiler heating surface, this HRSG was
arranged in 3 modules in width by 4 levels in height, instead of 2
modules wide by 5 levels height which would have applied otherwise
for a greenfield site.
Heating
surface
modules
flexible
arrangement
Standard
'greenfield'
arrangement
Senoko
enlarged
casing width
Modular construction
HRSG was made of 12 heat exchanger modules prefabricated and
hydrotested to reduce erection time. The largest module dimensions
was 23.6 meters long * 3.9 wide *2.9 heigth.
Heat exchanger modules unloading and transportation

Congested existing site

Boiler modules were transported by hydraulic trailer self propelled
which reduced convoy length and help to perform precise movements
with large angle orientation wheels in congested site
Heat exchanger
modules arriving at
the gate of the
existing power
plant (Site very
congested)
Modules erection using hydraulic jacks
28 hydraulic jacks
to lift modules on
top of structure
Vertical HRSG:
No large crane
was required.
Vertical HRSG Steel structure

with jacks on top for module
lifting
Modules erection using hydraulic jacks

Considering a congested site, the CMI Vertical HRSG
erection features:
- no module tilting performed
- no large cranes required
Horizontal HRSG
typical lifting
system
Modules erection sequence

The first row of 3 modules was hanged to cables and lifted up just
enough to introduce the next row of 3 modules. This operation was
repeated until all 4 levels of modules were suspended to one another.

Erection cables
Temporary plates
(peinted in yellow)
Final suspensions
First row of modules suspended


Hydraulic trailer self propelled had to manoeuvre in limited space.
Introduction of
the second row
of modules.

The module was positioned exactly and it was attached to the
module just above it on each support plates. Then, the hydraulic
trailer was lowered and released.
Erection of last row:

All modules remained
flat during the complete
erection sequence

Completion of 12
modules suspended
Only adjacent header

ends were
to2012be20welded
Power Plants
of 32

The complete assembly
(1450 tonnes) was then
jacked up on top of the
steel structure.
Hydraulic jacks were

released, dismantled
and installed on the
next unit.
All modules suspended in final
position inside the steel
structure

Boiler modules erection completed in 6 days only!
Indoor HRSG
HRSGs steel structure has been extended to an enclosure wrapped
all around for weather protection, noise abatement and aesthetic.
View of completed repowered

Senoko Power Plant
Repowering de Dunamenti G3 in Hungary
Unit 9
Unit 8
G3 to be repowered
Repowering Dunamenti - Project background

The GDF SUEZ Group, majority
owner of the Dunamenti power
station, Hungarys second largest
power plant, decided to upgrade its
G3 unit, a combined-cycle gas
turbine (CCGT) block, from 215 MW
to 400 MW, commissioning in 2011.
In
this
repowering
process,
Dunamenti, the existing gas-fired
steam turbine and installed a heat
recovery steam generator (HRSG)
and a gas turbine. This raised the
units efficiency from 36% to 57%.
The Dunamenti plant accounted for
7% of all electricity generated in
Hungary in 2010, producing 2.6
terawatt-hours.
View of the Repowered
Dunamenti Power Plant
Repowering Older Plants - The HRSG View

Repowering of old conventional plants into new efficient CCPP
(new GT-HRSG sets with old ST sets) is a cost effective solution,
because existing equipments remains such as steam turbine,
electrical distribution, cooling system, etc.
Permitting is also more easy as this is an existing power plant.
Compared to greenfield plants, repowering of old units always
requires tailor made design to match specific constraints:
- remaining equipment's (steam turbine, condenser, etc)
- limited available space of the old fired boiler
- minimum outage of the existing plant
- congested existing site
- indoor HRSGs
The Vertical HRSG has proofed to be very flexible and
accommodating for those specific repowering constraints.
Design Criteria for HRSG Heavy Fuel Oil Operation
Gas turbines are operated typically on natural gas, with no risk of

fouling and typical dew point at 60C. Both Horizontal or Vertical
HRSG are suitable for the purpose.
Heavy fuel oil has high sulfur content with Acid Dew Point (ADP)
up to 145C
Such high sulfur content requires a special HRSG design because

all metallic surfaces must remain above ADP to prevent internal
corrosion on tubes and ducting.
Temperature of condensate water entering finned tubes must be

controlled to remain above ADP to avoid acid formation on tubes
It limits the heat recovery in the back end of the HRSG
Ducting metal must remain above ADP which is not feasible with
internal insulation. HRSG must be externally insulated with ducting
remaining at inside flue gas temperature.
Design Criteria for HRSG Heavy Fuel Oil Operation

Combination of Heat Exchangers arrangement and Sootblowers
must maintain permanent industrial cleanliness of finned tubes:
Finned tubes
Maximum height of solid fins
Maximum fins density (160 fpm on heavy oil)
Staggered or inline arrangement with constant minimum
tubes pitches
Limitation of tube rows per bank
Sootblowers
Between tubes banks for
on-load cleaning
Rotary or Rake type parallel
to tubes
Boiler design for Fuel Oil is different than Natural Gas.
This requires specific boiler expertise with references.
Proven HRSG design for Distillate Oil
HRSG designed for continuous operation on distillate oil

Proven HRSG design for Crude Oil
HRSG designed especially for continuous operation with

crude oil and equipped with sootblowers
Conclusions
There is real potential for repowering of old steam turbines in the

Balkans. In a lot of old conventional plants, fired boilers have
exhausted their useful life before its steam turbine. Repowering of
those old steam sets into efficient combined cycle with new GTs and
HRSG is a cost effective solution. Today, available gas turbines can
provide the exhaust energy for steam turbines of 120 -150 MW of
which there are many examples in Europe dating back from the
1970s. These units could be repowered so as to increase power
supply with a significant improvement in operating efficiency,
flexibility and emissions. CMI has completed the Senoko and
Dunamenti plants, which are a very successful example of such
repowering. Vertical HRSG has been proofed to be very
accommodating for those the specific repowering constraints, which
always require a tailor made design to suit limited space. In addition
CMI Vertical HRSGs are uniquely fit behind Gas Turbine firing fuel oils.
Question time
Thank you for your attention
Europe: + 32 430 2810
Email: hrs@cmigroupe.com
Website: http://www.cmigroupe.com

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What are some of the challenges of repowering existing power plants?

What are some of the challenges of repowering existing power plants?

How can a vertical HRSG help address site constraints in repowering projects?

How can a vertical HRSG help address site constraints in repowering projects?

Repowering Older Plants - The HRSG View

International Conference Power Plants 2012

Oct 30th Nov 2nd , 2012

Heat Recovery Steam Generators offered by CMI

Power Plants 2012- 2 of 32

Inherent features Horizontal & Vertical HRSGs

Lets review the specific application of repowering power plants

Introduction to power plants repowering

Concept of Plant Repowering

1 : condensats - 2 : eau alimentaire - 3: eau alimentaire. IP - 4: eau alimentaire HP

9: eau dsurchauffe by-pass IP - 10: by-pass IP - 11- by-pass LP

Power Plants 2012- 5 of 32

Repowering Senoko - Project background

ALSTOM GT26 arrival at site

Original fired boiler had to

Vertical HRSG flexible layout

Overall boiler length 35 meters

Vertical HRSG flexibility layout

Vertical HRSG flexibility layout

Power Plants 2012- 10 of 32

Heat exchanger modules unloading and transportation

Congested existing site

Modules erection using hydraulic jacks

Vertical HRSG Steel structure

Power Plants 2012- 13 of 32

Modules erection using hydraulic jacks

Modules erection sequence

Power Plants 2012- 15 of 32

Modules erection sequence

First row of modules suspended

Modules erection sequence

Modules erection sequence

Power Plants 2012- 18 of 32

Modules erection sequence

Erection of last row:

Modules erection sequence

Only adjacent header

Modules erection sequence

Hydraulic jacks were

Modules erection sequence

Power Plants 2012- 22 of 32

View of completed repowered

Repowering de Dunamenti G3 in Hungary

Power Plants 2012- 24 of 32

Repowering Dunamenti - Project background

Power Plants 2012- 25 of 32

Repowering Older Plants - The HRSG View

Power Plants 2012- 26 of 32

Design Criteria for HRSG Heavy Fuel Oil Operation

Gas turbines are operated typically on natural gas, with no risk of

Such high sulfur content requires a special HRSG design because

Temperature of condensate water entering finned tubes must be

Design Criteria for HRSG Heavy Fuel Oil Operation

Proven HRSG design for Distillate Oil