Circulating Fluidised Bed Combustion

(CFBC) Boilers
Powerful solutions for steam generation

ThyssenKrupp Industries India

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Steam Generators with Circulating

Fluidised Bed Combustion (CFBC)
Technology

Boiler drum

Airbox

ThyssenKrupp Industries India offers a wide range of world-class

Circulating Fluidised Bed Combustion (CFBC) Boilers. A modern
concept in steam generators, these boilers are designed and
manufactured for a wide range up to about 550 TPH capacity.

These boilers display multi-fuel firing capabilities, high efficiency,

low emissions of SOx & NOx and can effectively utilise a variety of
Coals, Lignites, Petcoke, Char, Coal Washery Rejects etc.
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added to the fuel to capture

sulphur, if required to meet
stringent SOx emission norms.
The ash from the fluidised bed,
cyclone and ESP is conveyed
pneumatically to the main ash
silo, keeping the plant clean of
ash.
The boiler is designed for
fluidising velocities up to 4.5
m/s, generating high
turbulence and resulting in
good mixing of hot bed material
with fuel and recirculated fly
ash. The height of the bed is
kept constant through removal
of the produced bed ash as a
function of the differential
pressure between the airbox
and freeboard.
In the freeboard (upper part of
the combustion chamber), fine
fuel particles of size below 0.4
mm, that have been elutriated
from the fluidised bed, and part
of the volatile matter are burnt.
This post-combustion process
releases approximately 40% of
the total combustion heat which
is then is transferred to the flue
gas or, by way of radiation, to
the cooled combustion
chamber walls.
membrane tube walls. They are It is recirculated into the
The system part of the evaporator system combustion chamber via a
The amply dimensioned
freeboard height guarantees a
The fuel and the cold fly ash, and designed for natural siphon system which serves as mean residence time for flue
recirculated to the fluidised circulation. a seal. gases of at least 4 seconds.
bed, is well mixed with the hot The lower section of the first The heated combustion air from The correspondingly long
bed material resulting in boiler pass consists of the the air heater is passed through residence time of elutriated fuel
uniform temperature combustion chamber with the the air nozzles into the fluidised particles has its decisive share
distribution in the bed. This is fluidised bed and the freeboard bed as primary air and, above in the high degree of
achieved by higher turbulence above. The upper section is the fluidised bed, into the combustion and
caused by introducing fluidising made up of convection heating freeboard as secondary/ desulphurization efficiency.
air in smaller bed dimensions. surfaces: namely superheater, tertiary air. Combustion takes The recirculated fly ash quantity
Unlike Bubbling AFBC boilers, evaporator and part place within an optimum is adjusted to maintain the
erosion-prone submerged economiser. This first boiler temperature range of 800OC to fluidised bed temperature at
heating surfaces are dispensed pass is top supported, allowing 950OC. The flue gases are about 850OC. This quantity of
with. The recirculated cold fly easy expansion downwards. conducted to the chimney via fly ash recirculation suffices to
ash takes over the cooling of The second boiler pass has the an ESP and induced draught ensure the burn-out of fines
the fluidised bed. It is in the remaining part of the fan. and the capture of sulphur in
convection pass, that the heat economiser heating surface the freeboard with optimal
and the tubular air heater. The process of preparing the
taken is transferred to the fuel is relatively simple. The fuel consumption of limestone.
convectional heating surfaces. The elutriated fly ash is is crushed to a size of
The boiler has a tower-type separated from flue gases in approximately 8 mm and no
arrangement. cyclone separators located grinding of coal is necessary.
The first boiler pass is formed between the boilers first and The fuel is fed into the fluidised
by water-cooled, gas-tight second passes, at bed, together with recirculated
temperatures around 400OC. fly ash. Limestone can be
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Superior features of ThyssenKrupp

CFBC boiler
1. High efficiency (even at part loads)
- low operating cost.

2. Wide fuel band

- can burn Coal, Lignite, Coal Washery Rejects, Petcoke etc.

3. Simple fuel preparation

- no grinding required

4. Low emission levels

- due to staged combustion

5. Quick start up
- due to cyclone design

6. Good load chasing ability

- comparable to PF boilers

7. Low erosion risk

- no bed tubes

8. Reduced maintenance
- minimum refractory

Advantages of ThyssenKrupp CFBC Boiler over Bubbling Bed Boiler

Particulars Bubbling Bed CFBC (ThyssenKrupp) Advantage of CFBC (ThyssenKrupp)
1. Economic range <60 TPH 60-550TPH Lesser floor space requirement
Type 2-pass Tower
2. Thermal Eff. (Coal) 83% 87% Better efficiency due to ash recirculation
Carbon burn up 93% 98% and longer reaction time in large furnace.
Power consumption ~ 14 KW/MW (th) ~ 18 KW/MW (th) Higher bed height of 1600mm vs. 1300mm.
Fuel flexibility Limited range Wide range Staged air, larger furnace volume, more
Fuel preparation <8 mm <8 mm residence time
Fuel fines <1mm <20% <50% No monsoon problems of feeder jamming &
Fuel Moisture ~10-12% ~16% coal pipes jamming
3. Reliability Low Very High No inbed tubes, No erosion problems
Response Poor Very good Equal to PF
Auto Controls Combustion control not possible Possible Stepless turndown up to 30% achievable.
4. Fluidising velocity 2-3 m/sec 4-5 m/sec Leads to more compact furnace.
Furnace Resi. Time 2-3 sec. 4-5 sec.
Bed heat release ~1.5 MW/m ~5.0 MW/m
5. Bed Temp. Falls at part loads Constant Much better part load efficiency
Bed Temp. Control In-bed tubes & bed partition Ash recirc & staged combustion Auto combustion control possible.
Bed level control Intermittent draining Intermittent draining No bed tube erosion
6. Emission (mg/Nm )
-NOx <600 <200 Due to larger furnace & staged combustion
-SO ~300 ~300 Due to ash & Limestone recirculation
Limestone requirement More Less
Desulferisation Limit 85% 95%
Meets pollution Norm No Yes
7. Quick & +ve start-up No Yes Start-up using Hot Gas Generator
8. Ease of Operation Less More Simpler systems, auto controls
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Advantages of ThyssenKrupp CFBC Boiler over Pulverised Fuel Boiler

Particulars Pulverised Fuel CFBC (ThyssenKrupp) Advantage of CFBC (ThyssenKrupp)
1 Thermal Efficiency ~87% ~87% Practically same
2. Power consumption Higher due to grinding Lower than PF No milling equipment
3. Oil Firing Start up & upto 50% load Only start up Big savings in oil as no oil required for part lod operation
4. Fuel preparation <75 micron <8 mm No grinding of fuel. Less power.
- Fuel Flexibility Limited Wide range Very poor fuels can be burnt like lignite & washery rejects
- Max. Ash + H O ~62% ~ 75%
- Abrasive coals High Mill Wear & maintenance None Adequate precaution taken for pressure part
- High sulphur fuels FGD Plant reqd. CaCO dosing In situ SO capture
5. Emission (mg/Nm )
- NOx ~ 650 <200 Low NOx due to low combustion temp. of about ~850 C
- SO ~ 2600 ~300 Meet pollution low of future also
6. Start up time ~ 5 hrs. with multiple burner 3-4 hrs with 2 Hot Gas Gen. Big saving in oil bill & over all plant operation cost
7. - Moving Equipment Feeders, Mills Only feeders No mills
- Maintenance High Low Maintenance friendly
8. Pressure Part
- Arrangement 2 Pass type Tower type Lesser floor space requirement.
- Erosion Moderate Less No gas turns on tube banks so less wear
9. Soot Blowers Many & all over None No steam consumption or maintenance
10. Space More Less Compact layout
11. Ash Handling Wet & Dry Dry System very simple, clean & automatic
12. Explosion Risk High None Safe & reliable operation
13. Boiler Control Complicated Very Simple
14. Burner Controls Complicated Very Simple Only 2 Hot Gas Generators
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Blue chip references

No. of Capacity Pressure

Client & location Fuel
Boilers (TPH) (Bar)

Tata Chemicals, Mithapur, Gujarat 2 220 112 565 Lignite/ Petcoke/ Coal

Nava Bharat Ferro Alloys, Paloncha, Andhra Pradesh 2 151 91 530 Coal

Hindalco, Hirakud, Odisha 11 165 90.2 515 Coal

HEG, Mandideep, Madhya Pradesh 1 140 66 485 Coal

Jaiprakash Associates, Rewa, Madhya Pradesh 1 170 87 515 Coal/ Washery Rejects

India Cements, Sankar Nagar, Tamil Nadu 2 115 100 545 Coal

Ultratech Cement, Tadipatri, Andhra Pradesh 4 115 112 540 Coal/ Washery Rejects

Bhushan Power & Steel, Sambalpur, Odisha 1 390 105 535 Washery Rejects / Coal/ Char

Anrak Aluminium, Vizag, Andhra Pradesh 3 315 112 540 Indian/ Imported Coal

BIDCO, Uttar Pradesh 6 190 110 540 Coal

PT Megadaya Tangguh, Amurang, Indonesia 2 130 100 535 Indonesian Coal

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Integrated approach, comprehensive solutions

Customer
Turnkey solutions
in steam generation
Concept
After-Sales Development ThyssenKrupp Industries India designs,
& Service manufactures, supplies, installs and
Support commissions a wide range of Steam
Generating Plants for various industrial
Process /
Systems
applications. The boilers serve diverse
Design needs of different industries with multi-fuel
firing capability, high efficiency and
Installation ThyssenKrupp environment-friendly steam generation
& Design &
Commissioning Industries capabilities.
Engineering
India (Mechanical, The boiler range covers water tube boilers
Electrical, up to 550 tph and includes:
Instrumentation, n CFBC Boilers
Civil)
n Oil & Gas Fired Boilers
Manufacturing
& Quality n Waste Heat Recovery Boilers
Assurance Project
n Unconventional Fuel Fired Boilers
Management
Procurement
n Biomass Fired Boilers (Dumping /
Traveling grate)
Locations
OFFICE & FACTORY
PUNE
Pimpri, Pune - 411 018, India
Telephone : (020) 2742 5461 - 64
Fax : (020) 2742 5350
E-mail : contactus.tkii@thyssenkrupp.com
HYDERABAD
Cherlapally, Hyderabad - 500 051, India
Telephone : (040) 2726 3540 / 2726 3896 / 2726 3647 / 2726 2762
Fax : (040) 2726 3162/ 2726 2762
E-mail : tkii.hydbad@thyssenkrupp.com

REGISTERED OFFICE
MUMBAI
154 C, Mittal Tower, 15th Floor, 210, Nariman Point
Mumbai - 400 021, India
Telephone : (022) 2202 0064 / 6837
Fax : (022) 2204 4025
E-mail : tkii.mumbai@thyssenkrupp.com

BRANCHES
CHENNAI
Temple Tower, 5th Floor, Nandanam
672, Anna Salai, Chennai - 600 035, India
Telephone : (044) 2431 4235 / 2433 9482
Fax : (044) 2434 8198
E-mail : tkii.chennai@thyssenkrupp.com
KOLKATA
Eco-Space, Premises No.701, Block-A
7th Floor, New Town, Rajarhat, Kolkata - 700 156. India
Telephone: +91 33 6605 5200/01
Fax: +91 33 6605 5218
Email : tkii.kolkata@thyssenkrupp.com
NEW DELHI
407 A, Hemkunt Tower, 98, Nehru Place
New Delhi - 110 019, India
Telephone : (011) 2644 9971 / 72 / 73
Fax : (011) 2646 8968
E-mail : tkii.delhi@thyssenkrupp.com

ThyssenKrupp Industries India Pvt. Ltd.

Pimpri, Pune 411 018, India
Phone: +91 20 2742 5461-64
Fax: +91 20 2742 5350
Corporate Identity No. : U74999MH1947PTC005508
E-mail: contactus.tkii@thyssenkrupp.com
Internet: www.thyssenkrupp-industries-india.com