B&W

Atmospher ic F lu id ised Bed Combust ion Boi lers

for F i r ing Sol id Fuels

Historically, Babcock & Wilcox has maintained an ongoing program to develop advanced

technologies which offer the potential for more efficient, cost effective and reliable steam

generation. One of these advanced technologies is Atmospheric Fluidised Bed

Combustion (AFBC), which promises to provide a viable alternative to conventional coal

fired and other solid fuel fired boilers for utility and industrial applications.

B & W began investigating various aspects of the AFBC process in the mid -70s and has

become the technological leader among boiler manufacturers in AFBC development for

utility and industrial use.

ADVANCED TECHNOLOGIES

FOR POWER GENERATION

Flow Modelled Fuel Feed System

Combustor Components

Fuel Feed Mixing Nozzles Studded Carbon Steel Inbed Evaporator and

Stainless Steel Inbed Superheater Tubes

Atmospheric Fluidised Bed Combustion Boilers (AFBC)

Secondary Over Fire Air Arrangement

110 TPH AFBC Control Room

SALIENT FEATURES OF TBW AFBC BOILER

Boiler

Furnace

Cold AirCold

Ash

Drain

Hot

AirHot

Bed

Ash

Fluid bed ash coolers for cooling bed

ash. Air is used to cool ash. Flue gas

sent back to the air heater to recover

sensible heat resulting in further

improvement in efficiency.

Inclined airholes prevent bed material re-entry

eliminating back shifting.

Stainless steel air (Bubble Cap) nozzles for primary air

are designed for higher pressure drop to achieve

higher turndown ratios. The entire nozzle including the

shaft pipe is made of stainless steel.

Underbed fuel feed system using drag chain

feeders for smooth flow of high moisture

fuel to furnace. Hot air for transport of fuel

inside combustor for smooth flow of fuel in

the feed lines. No bends on fuel transport

lines improves availability.

Secondary overfire air is

provided from both sides of

furnace to ensure complete

combustion, resulting in

minimum unburnt, reduced

c a r b o n m o n o x i d e a n d

improving efficiency.

B&W design two stage

s t e a m s e p a r a t i n g

equipment inside the

drum ensures turbine

q u a l i t y s t e a m .

Guaranteed 99.99 %

steam purity even

under conditions of

rapid load changes.

In line, spaced bed evaporator tubes for

better access to bed plate. Pin studs welded

on inbed surfaces and furnace walls

eliminate tube erosion completely.

Distributor plate 16 mm thick carbon steel.

Shop assembled, machine

welded membrane panels

allow for less refractory and

make a gas tight enclosure

resulting in less leakage and

improved efficiency.

The challenge of the AFBC process is to burn fuel in an environmentally acceptable manner yet showing economic

promise. The AFBC Boiler achieves this by carrying out combustion in a bed of crushed refractory / sand which is

suspended by an upward stream of air, fluidising it and facilitating a significant higher degree of combustion

completeness. In addition to this inherent advantage of the fluidised bed combustion process, design and operating

characteristics of TBW AFBC boilers offer a number of advantages for industrial steam and power generation.

Combustion temperatures of the AFBC process are maintained below the fuel ash softening temperature, so low-

grade fuels can be burned without the risk of slagging and fouling in the boiler. The lower temperatures also limit the

formation of nitrogen oxides. Fuels like coal, washery rejects, lignite (Kutch, Neyveli), petcoke, rice husk, DOB,

bark, effluent sludge from paper mills, viscose plant, coffee waste etc. can be effectively burnt in TBW

AFBC Boilers.

Due to lower operating temperatures, the TBW AFBC boiler design is less dependent on fuel and fuel ash

characteristics than conventional boilers.

SOx control is achieved by limestone addition.

sludge from

Load Vs Efficiency

EFFIC

IEN

CY

83

82

84

85

86

87

88

LOAD % MCR

30 40 50 60 70 80 90 100 110

Fuel : Coal with 45% ash

TBW TECHNOLOGY :

HIGH AVAILABILITY & EFFICIENCY

Boiler Availability*

JA

N 0

2

FEB

0

2

MA

R 0

2

AP

R 0

2

MAY

0

2

JU

N 0

2

JU

L 0

2

AU

G 0

2

SEP

0

2

OC

T 0

2

NO

V 0

2

DEC

0

2

% A

VA

ILA

BIL

ITY

0

100

MONTHS

* Based on actual observations at an operating unit.

71.5

98.11100

93.82

20

40

60

80

100

120

99.44 100 100 100 100 100 100 100 100 100

59

100

90.5

100 100

94.4

100 100 100

JA

N 0

3

FEB

0

3

MA

R 0

3

AP

R 0

3

MAY

0

3

JU

N 0

3

JU

L 0

3

AU

G 0

3

SEP

0

3

OC

T 0

3

NO

V 0

3

DEC

0

3

Plant

Shutdown

Planned

Shutdown

Capacity

Enhancement

Designed and manufactured to the legendary Babcock & Wilcox quality incorporating the latest advances in boiler and control technology,

making it the most efficient and reliable boiler for combustion of diverse range of difficult fuels.

Capacity Range : Up to 300 TPH

2

Pressure : Up to 135 Kg/cm g

Temperature : Up to 540 C

Fuel : Coal / Lignite / Petcoke / Rice Husk / Pith /Oil / Agricultural Waste /

Washery Rejects / Char / Biomass / Spent Coffee Waste / Spent Tea

Waste, etc., Sawdust, DOB

Design Feature : Top or bottom supported, Single or Bi-drum design boilers suitable for

firing low calorific value fuels. Suspension burning of fuel - higher

combustion efficiency.

Coal Size 6 mm Bubbling Bed Ash Coolers Stainless Steel

Inbed Superheater Stainless Steel Fluidizing Nozzles Boiler

Bank without Baffles High Steam Purity Membrane Wall Furnace

Start-up by Oil / Charcoal

ATMOSPHERIC FLUID BED

COMBUSTION BOILER

(Underbed & Overbed feed system design)

FUEL

BUNKER 1

FUEL

BUNKER 2

ASH

DRAIN

PIPES

P A FAN

STEAM

DRUM

ACCESS

DOOR ON

L,H, SIDE

GROUND

Salient Features

! Combustor does not have any moving parts thus reducing

maintenance in the furnace.

! Uniform Temperature distribution in the bed and agitating

characterstic of fluid bed ensures optimum combustion.

! Low excess air requirement resulting in higher efficiency.

! Lower NOx and CO emissions.

! Low SOx emission with limestone addition.

! Low temperature operation minimises the biomass fuel

ash agglomeration and fouling tendency.

HOPPER BOTTOM (FLUID BED)

! Continuous slow draining of bed ash which aids:

= Easy settling and disposal of large sized particles which

hamper fluidisation.

= Maintaining alkali concentration below acceptable levels.

= Avoiding accumulation of denser particles in bed in

maintaining uniform bed density across the entire bed.

! Under bed / over bed fuel feeding for proper distribution

of fuel.

AFBC INSTALLATIONS

CLIENT NOS2

Kg/cm g FUEL YEARCap,

(TPH)Deg C

Mysore Paper Mills 2 60 63 460 Coal 1991

Central Pulp Mills 1 50 42 440 Coal/Lignite 1992

BILT for Sewa Paper Mills 1 45 42 440 Coal 1992

Mysore Paper Mills 1 60 63 460 Coal 1993

Nestle India Ltd. 1 14 24 Sat Spent Coffee Grounds, Coal, 1994

Coconut Shell, Spent Tea

JK Corporation 1 60 37 410 Coal 1995

Servall Engineering 1 44 13 209 Lignite 1995

GHCL 1 90 105 505 Lignite/Coal 1996

L&T 2 95 66 495 Coal/Washery Middlings 1996

Vardhaman Acrylic Ltd. 1 42 45 420 Coal 1997

L&T for Usha Martin 1 110 66 495 Coal 1998

Jocil Ltd. 1 30 66 485 Rice Husk, Coal, Cotton Stalk, Julia Fora 1999

JCT Ltd. 1 35 44 420 Coal. Rice Husk 2000

Khanna Paper Mills Ltd. 1 70 66 485 Rice Husk/Padtal 2000

India Glycols Ltd. 1 45 34 400 Rice Husk/Coal/Bio-Gas 2000

Oswal Chemical & Fertilisers Ltd. 2 110 63 485 Coal 2001

Saro Power & Infrastructure Ltd. 1 35 66 495 Coal/Rice Husk, Cotton Stalk, Julia Fora 2001

Shree Cements Ltd. 2 80 65 495 Imported Coal, Petcoke, Lignite 2001

Nestle, Thailand. 1 15 18.5 Sat Spent Coffee Ground 2001

Nova Petrochemicals Ltd. 1 47 47 495 Imported Coal, Petcoke, Lignite, 2001

Indian Coal, Sawdust/GN Shell

Nav Bharat Ferro Alloys Ltd. 2 65 93 515 Coal/Washery/Petcoke 2002

Sangam Spinners 1 50 66 495 K. Lignite/Petcoke 2002

Chaddha Papers Ltd. 1 50 65 490 Coal/Rice Husk/Petcoke 2002

Bhushan Ltd. 1 75 88 520 Washery Rejects/Char 2003

Sree Rayalseema Alkalies & 1 100 100 525 Coal 2003

Allied Chemicals Ltd.

Gujarat Ambuja Cements Ltd. 2 45 67 495 Rice Husk/Coal/Petcoke 2003

Nestle Russia Ltd. 1 18 22 Sat Spent Coffee Ground/Natural Gas & Diesel 2003

Khanna Paper Mills Ltd. 1 100 66 500 Petcoke/Rajasthan Lignite Paper Sludge 2003

& Plastic waste

West Coast Paper Mill 1 65 43.5 415 Coal 2003

Chettinad Cement Ltd. 1 68 87 515 Imported Coal, Indian Coal, Neveyli Lignite 2003

Madras Cement Ltd. 2 76 89 515 Imported Coal, Petcoke, Lignite 2003

Nestle Philippines Inc. 1 24.95 18 D&S Spent Coffee Ground, Green Coffee 2004

Residue, Roasted, Roasted Chaffs & HFO

ITC, Dakshin 1 60 64 485 Lignite, Sawdust, DOB 2004

Bhushan Ltd. 1 165 88 520 Washery Rejects/Char 2004

South Pacific Viscose 1 45 45 450 Coal/Viscose Sludge 2004

AFBC INTALLATIONS / FEATURES

Usha Martin Industries Ltd.

Jamshedpur

Capacity : 110 TPH

Fuel Used : Coal

Research & Development

Shot Blasting Machine

Furnace Panels

in Shop Floor

OTHER PRODUCTS & AFBC FEATURES

Inbed Evaporator

Assembly at Shop

Stainless Steel Dense

Studs for Inbed Tubes

Membrane Welding

Installation at Kanoria Chemicals

Capacity : 105 TPH

Fuel used : Coal

CFBC Boiler

B&W

Thermax Babcock & Wilcox Limited

Pune

D-1 Block, Plot No 7/2, R.D. Aga Road,

M.I.D.C, Chinchwad, Pune 411 019, India.

Tel: 91-20-4126464 Fax: 91-20-27479200

Email: tbw@vsnl.com

Mumbai

Dhanrajmahal 2nd floor,

Chhatrapati Shivaji Maharaj Marg,

Near Gateway of India, Colaba,

Mumbai 400 039, India.

Tel: 91-22-22045391, 22045324,

Fax: 91-22-22040859

Delhi

9, Community Centre, Basant Lok,

New Delhi 110 057, India.

Tel: 91-11-26145319, 26145326,

Fax: 91-11-26148679

Chennai

Fatima Akthar Court,

3rd floor, 312 Anna Salai,

Teynampet, Chennai 600 018, India.

Tel: 91-44-24353831, 24353834,

Fax: 91-44-24353841

Kolkata

Azimganj House, 5th Floor,

7 Camac Street, Kolkata 700 017, India.

Tel: 91-33-22826711/2/3,

Fax: 91-33-22826796

Hyderabad

6-3-649 Nalanda Complex

Somaji Guda, Hyderabad 500 082 India.

Tel: 91-40-23310254, 23312013, 23396820

Fax: 91-40-23312335

www. tbw ind i a . com Synerg

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