BABCOCK & WILCOX C I R C U L A T I N G F L U I D IZ E D - B E D B O I L E R A n
Overview of B& W CF B Boiler Technology
The Babc ock & Wilcox circulating fluidize d-be d (CFB) b oiler is designe d f o r hig h reliability and availability with low maintenance, while complying with stringent emission regulations B& W's CFB techno logy is unique and includes a simple U-beam particle sep arator design. This is the result o f extensive research and develop ment an d com mercial operating experience. B& W and it s jo in t ve ntur e co mpa nie s hav e sold more than 38 fl uid iz ed-bed p roje cts o f whic h 10 ar e atmospheric circulating fluidiz ed-b ed boilers.
CFB PROCESS •
H o w t h e B & W C F B I n t e rn a l C i r c ul a t io n B o i le r W o r k s
In a circulating fluidized-bed boiler, a portion of com bustio n air is introduced throug h the botto m o f the bed. The bed material normally consists of fuel, limestone and ash. The b ottom of the bed is supported by water-cooled m em bra ne walls with specially designe d air nozzles which distribute the air uniformly . Th e fuel and lim eston e (for sulfur capture) are fed into the lower bed. In the presence o f fluidizing air, the fuel and limestone quickly and uniformly mix under the turbulent environment and behave like a fluid. Carbon particles in the fuel are expo sed to the combu stion air. The balance of com bust ion air is introduced at the top of the lower, dense bed. This staged combustion limits the formation of nitrogen oxides (N O) . The bed fluidizing air velocity is greater than the terminal velocity of mo st of the particles in the bed and thus fluidizing air elutriates the particles through the comb ustion cham ber to the U- bea m separators at the furnace exit. The captured solids, including any unburned carbon and unutilized calcium oxide (CaO), are reinjected directly b ack into the combu stion chamb er without passin g through an external recirculation. This internal solids circulation provides longer residence time for fuel and limeston e, resulting in good combustion and improved sulfur capture.
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CFB Steam Generator
The CFB boiler is arranged with a single furnace havin g full-height/partial depth s traight-tube division wails with or without steam-cooled wing wails. The furnace and particle separator enclosure walls are com pos ed of water-cooled m em bra ne tubes. The superheater enclosure is a comb ination of steam-co oled and water-cooled mem bran e tubes. Feedwater enters the unit at the econo mizer inlet, flows through the econom izer banks in the convecti on pass to the outlet header, and then to the steam dru m feedwater inlet. Water in the dru m pass es through
large downc om ers an d multiple supply tub es to feed the enclosu re walls and division walls. Steam-water mixtu res from the va rious circuits flow throu gh headers and riser tribes back to the drum. Saturated ste am is routed from the dru m to the superheater enclosure side wails (if supplied) and then to the primary superhe ater located in the conv ection pass. Steam then travels to the inlet heade rs of the superhe ater wing walls ( if supplied) in the furnace. Steam p assing throu gh the wing walls is collected and routed bac k to the secon dary supe rheater through spr ay attemperators. The stea m passes thr oug h the secon dary superheater a nd d ischarges to the outlet terminal adjacent to the boiler.
CFB BOILER MAJOR SYSTEMS •
Circulating Fluidized-Bed Furnace
The furnac e design has been develope d from B& W's 30 years o f experience with fluidized-bed techn ology. The me cha nics of fuel a nd limes tone feed, air distribution, start-up syste m, refractory, bed drains, watercooled walls, etc., a re based on research and d ev elopmen t and comm ercial operating units. The CFB furnac e operates as an extend ed fluidized bed o f solid particles. M ost o f these entrained solids recirculate within the furn ace or are captured by the primary impact separator (U-be ams ) at the furna ce exit and are returned internally to the botto m of the furnace. Com bustio n.air is admitted to the furna ce as follows: •
Primar y air
throug h a bubble cap air distributor in the furna ce bottom.
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Seco ndary air
throug h nozzles and material injection points at two levels in the lower furnace.
The region of the furnac e below the lower secon dary air level is called the primar y zone. The circulating fluidized bed form s two distinct regions: •
Den se bed in the primary zone { 14 ft/s (4.25 m/s)}.
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Dilute bed in the middle and uppe r furnace { 19.7 ft/s (6 m/s) }.
The transition between these two regions is gradual, and operating experience indicates low eros ion potential. The solids densities in the dilute bed and transitional regions of a circulating-bed com bus tor are relatively high. This results in high er rates of ga s-solids reactions for combu stion, sulfur capture and heat transfer between the bed and the fur nace walls. The furnac e height is selected to maxim ize carbo n burnou t and sulfur capture. B&W operates higher solids densities compared to other suppliers to optimize sul fur capture and heat transfer.
The material separated by the U-beam primary separator at the furnace exit is returned to the lower furnace by gravity, falling as a curtain along the rear furnace wall. In the lo wer furnace, these solids are reentrained by prim ary and secon dary air and carried back to the furnace exit. This intensive furnace backmixing provides uniform distribution and optimum residence time. Finer solids not collected by the primar y separato r are carded by gas es through the convection pass, are collected by the se condar y separator, and are recirculated to the l ower furnace.
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Dens e Bed in the Prim ary Zone
The primary zone design provides for uniform distribution and intensive mixing o f primary com bustion air and bed solids supplied by material feed systems and recirculated from the primar y and seco ndary separators. The cross section o f the prima ry zone is reduced relative to the upper furnace to pro mote go od mixin g and turbulence and to ensure solids entrainment throughout the boiler load range. The high rate of mass transfer in the prim ary zone provides intense combustio n and calcination/sulfation reactions. The substoichiometric conditions in the primary zone promote con ver sion of fuel nitrogen compou nds to elemental nitrogen, thus r educing NO x formation.
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D iL u te B e d i n t h e M i d d l e a n d U p p e r F u r n a c e
The middle and u pper sections of the CFB furnace are designed for the following: •
sufficient residence time for fuel burno ut and sulfur capture,
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high solids inventory for improv ed heat transfer rates and sorben t reaction surface,
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heat transfer surface of the enclosure walls, in-furnace division, and wing wails, and
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good mixing of secondary air and combustion products.
AIR AND GAS SYSTEMS Air fro m the primar y air fan or forced draft fan (single fan option) is heated by a steam coil air heater and flows across a partitioned section of the tubular air heater. It is then directed to a water-cooled wind box at the bottom o f the furnace. This windb ox is divided into many compa rtments across the width o f the unit, with dampers to control the flow of primary air to each compartment. A portion of the primary is also admitted to the furnace thr ough the fuel chutes. A duct burne r is installed in each main pr imary air feed duct to facilitate boiler start-up. Air from the secondary air fan or forced draft fan is heated by a steam coil air heater and pass es throug h the secondar y section of the tubular air heater. This second ary air flows to the distributing nozzles located across the width of the furnace on both the front and rear wails. Dampers vary the proportions of the secondary air to the fron t and rear distributing nozzles.
A portion o f the seconda ry air is admitted to the furnace through overb ed burners.
A portion o f the seconda ry air is admitted to the furnace through overb ed burners. The flue gas with entrained solids leav es the furnace through the U-bea m primary p article separator, a nd passe s through th e convective heat recovery pass to the secondary separator. The flue gas with an y remain ing fine particles contin ue thro ugh the air heater. Most o f these remain ing fine particles are remo ved at the bag hou se or electrostatic precipitator (ESP).
SOLIDS SEPARATION SYSTEM The solids separation system s is a key eleme n t of any CFB boiler design, influe ncing both capital an d operating c osts. The separa tion sy stem affects the solid inventory in the f urnace, which impacts furnac e tempera tu re contro l (furnac e heat transfer), c arbon bu rnout and limestone utilization. T he B &W CFB boiler uses a two-stage solids separation system : Prim ary particle separators - U- bea ms •
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Seco ndary particle separator system - multi-cyclo ne dust collector (MD C) or ESP
The Prim ary Particle Separato r (U-Beams)
B& W uses an impa ct for primary particle collection, whic h is different from ho t cyclones comm on ly u sed for CFB boilers. B &W 's imp act separ ator is unique in CFB boiler design. Impact separa to rs h ave b een used for se veral de cades to separate particles greater th an 100 microns. T he dust laden gas stream impinges on the staggered vertical a rrangement of U-bea m channels. B & W has conduc te d considerable res earch and deve lo pme nt on impact separa tors on the Cold Mod el T est Facility at B& W' s Alliance Resea rch Center. Geometrical cor relations have be en developed based on o perating variables such as gas velocity; solids loading, num ber of chann el rows, and particle size. Thes e relationships have been applied succ essfully to B & W's c om mercial CFB b oiler designs . B & W primary solids collector consists of two (2) rows of U-bea ms located within th e furna ce at the gas exit and four ( 4) additional rows of U-b eams loca ted immed iately down stream of the in -furnace U-beam s. Solids collected by the front two rows discharge downward directly to the furnace along the rear wall. Solids collected by the rear rows o f U- be am s discharge into a hopp er integral to the furnace rear wall and return by grav ity to the furnace throu gh openin gs distributed across the width o f the unit. These U -beam s a re mad e of stainless steel. Individual U-beam s a re in th e form o f channels six inches (152 ram) wid e by seven inches (178 m m) deep. Two bolts th rough the water cooled roof susp end each beam, protected by an enclosure. Dynamic (gas and solids) stresses, static (dead load) stresses, design tempera tu res and m aterial creep strength are use d to design the U-beam s. A pan at the lower end o f each U-be am holds the U-beam in alignm ent and accom moda tes horizonta l a nd vertical thermal expa nsion. These pa ns also form a gas barrier at the bottom disc harge end of the bea ms to prevent ga s bypass ing and impro ve particle collection. B& W's operating exper ie nce with U-b eam s has
been ver y success ful. The U-bea ms have m aintained ge ometry and structural integrity with no erosion. Erosion potential is low du e to the chro miu m oxide scale that forms on sta inless steel at furnac e operating tempera tures. Lower gas velocity through the U-b ea m and desig n with all impact ang le s at 90 d egrees a re also favourable. The U-b eam supports have maintained their o riginal condition o ver time.
B&W CFB Boiler Impact Separator Offers Several Advantages •
U- be am separators, an integral part of the top- supported boiler, are easy to install and repair.
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No high tempera ture flue gas expa nsion joints or refractory-lined ducts are required. Building v olume is redu ced. The uniform, low veloc ity gas flow acros s the wid th o f th e boiler at the furnace exit red uces the erosion potential in the upp er furnace an d the collectors.
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There is no thick refractory to limit start-up and load cha nge rates.
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Mai ntena nce costs are lower beca use of less refractory.
Secondary Particle Separator System
The seco ndary sep arator is a conventional multi-cyclon e dust collector or the first pass o f the ESP. The small diameter low temperature collecting cans in the MDC allow for higher fine particle collecti on efficiencies. The two stage particle separation syste m with high efficiency secon dary separation provid es overall c olle ction efficiencies well in excess of 99 .7%. T his allows the B&W CFB to a chieve the high er furnac e densities and uniform ve rtical tempera tu re profile in the furnac e. B&W 's co mme rcial units with in-furna ce U-Bea ms typically h ave furnac e temperature variations along the furnace heig ht o f only abou t 25°F (14°C) at full load.
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The M DC or first pass ESP helps mana ge inventory on especially low ash input fuels suc h as a low a sh and low sulp hur coal. It also enhan ces calcium utilization and carbon burno ut of fine material. The co nvection pass is designe d to accom modate the so lids recirculation around th e M DC or ESP loop. The U-B eam s capture substantially all material above 30 0 microns and almo st all material abov e 200 microns. Th is r esults in dust loadings through the c onvection pass which ran ge from as low as 0.05 lb (0.023 kg ) to 0.025 lb (0.1 lkg) per poun d (0.4536 kg) of flue gas. B& W' s experience w ith conve ctive heating sur face performa nce has been excellent. Convection pa ss tube erosion is m inimize d due to lower flue gas velocity [30 to 40 ft/s (9.1 to 12.2 m/s)] and in-line tube arrangem ents. The M DC or ESP solids hopper is located at a high elevation, whic h allows use of an air assisted, gravity return recycle s yste m from the secondar y collector. This sy stem uses ro tary valves with low pressur e drop to control solids flow. A small volu me of fluidizing air from the primary air fans allow the material to mov e back into th e furnac e through multiple return points ac ross the width of the furnace rear wall.
Bed tempera tu re control is enhan ced by usin g solids inventory located under ne ath the multicyc lo ne dust
Bed tempera tu re control is enhan ced by usin g solids inventory located under ne ath the multicyc lo ne dust collector or as a separa te hopp er in the case o f first pass ESP collection. W h en the furnace temperature increases above the target, bed material from the particle storage is transferred to the furnace by increasin g the recycle flow rate from the mu lti-cyclone or the hopper. The increased invento ry of circulating material enhanc es furna ce heat transfer, thus reduc ing bed temperature. Inversely, when th e bed tem perature decreases, the inventory of circulating solids in the furnac e is reduc ed by slowing dow n the recycle rate from the MD C or the ESP hopper, and circu lating material is tr ansferred to storage. This contro l m etho d is used both d uring cons ta nt load opera tion and during load change to impr ove the load follow ing capability and provide a wider turn-dow n ratio. The curren t de sign of the B&W two-stage particle seParation syste m exceed s the performan ce o f a standalone cyclon e-base d CFB system, providing higher o verall c ollection efficiency. Design features o f th e convec tio n pass, multi-cyclone dus t c ollector and d ust collector recy cle provide an econ omical syste m which also reduces erosion potential a nd auxiliary power consump tio n.
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Bed Drain and Cooling System
Bed ash is purge d from the furnac e to control bed solids inventory and remove oversized material that may enter the fuel. Material exits the furna ce throu gh bed drains. These so lid s are at bed temperature and must be cooled prior to handling. Water-cooled screws or fluidized-bed coolers are used to cool the material and control the rate of m aterial drained. It is desirable to minim ize the amo unt of material d rained from the furnac e becau se the high tempera tu re at wh ich it is dr ained results in a sensible heat loss. Strict control of fuel size decreases the amou nt of material that mu st be drained th rough the bed drains by reducing th e amo unt of oversize d material that enters with the fuel. Solids exiting the water-co oled screws pass th rough a screen whic h remo ves mater ia l g reater than 2000 microns. Th e screened solids then enter the ash rem ov al system. With fluidized-bed coolers, particles less than 350 microns are injected back into the furnace.
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Convective Heat Recove ry System
The vertical penda nt ty pe superhe ater designed for a C FB boiler is unique an d non-dra inable. The design provides m etal temp erature protection during start-up. A vertical pendant su perheate r is located after the four (4) ro ws o f external U-be ams . Sup erheater erosion p otential is considerably reduced due to very low gas velocities. Unifo rm gas distribution is ensured to the superheater for better performance. Th e superheater sections are encas ed with either steam-co oled or water -cooled walls. The econom iser is designe d with ba re tubes enclosed in a carbon steel casing. Economise r surface is arrang ed in-line to avoid ash bu ild -up between the tube ban ks. Econom iser surfa ces are designed very conserv atively due to varying con vection pass dust loadings and to ac comm odate a ran ge of fuel ash content. B& W' s operating experien ce indicates that sootblowers are not required.
Key Features / Benefits of B & W CFB Boilers
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Techn ology is suitable to bu m a wide range of fuels, or opportunity fuels with less exp ensi ve fuel preparation. (Fuels burned in B & W CFB boilers are high ash-waste coal, high su lfur coal, lignite, pet. coke, anthracite culm, wo od waste, etc.)
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Use state-of-the-art CFB techno logy to achieve lower em issio ns levels. (Sulfur capture is >90 % a n d N O x emission is <10 0 ppm)
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Provides higher reliability, operability, availability with lower mainten ance. B & W' s CFB boiler has on e-fifth of the total refractory of the hot cy clone CFB boiler. B & W CFB boiler availability is frequently more than 95%. Boiler building volu me is conside rably reduce d because most o f the U-beam s are locate d in side the furnace. B uilding volume is r educed by 20 to 3 0% w hen com pared to the cyclone- based CFB boiler design. Boiler design allows wider load swing
with high turn-d own (appro ximately 5:1) without auxiliary
Key Features / Benefits of B & W CFB Boilers
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Techn ology is suitable to bu m a wide range of fuels, or opportunity fuels with less exp ensi ve fuel preparation. (Fuels burned in B & W CFB boilers are high ash-waste coal, high su lfur coal, lignite, pet. coke, anthracite culm, wo od waste, etc.)
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Use state-of-the-art CFB techno logy to achieve lower em issio ns levels. (Sulfur capture is >90 % a n d N O x emission is <10 0 ppm)
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Provides higher reliability, operability, availability with lower mainten ance. B & W' s CFB boiler has on e-fifth of the total refractory of the hot cy clone CFB boiler. B & W CFB boiler availability is frequently more than 95%. Boiler building volu me is conside rably reduce d because most o f the U-beam s are locate d in side the furnace. B uilding volume is r educed by 20 to 3 0% w hen com pared to the cyclone- based CFB boiler design. Boiler design allows wider load swing s, with high turn-d own (appro ximately 5:1) without auxiliary fuel support. Auxiliary power co nsum ption by B & W CFB boilers is relatively lower com pared to cyclonebased CF B boilers. B & W CFB boilers do not require high pressure blowers. B & W CFB boilers have .625 in. (15.9 m m) thin refractory. Therefore, virtually no limitation on start-up (usua lly less than 6 h ours to reach full load) U- Be am flue gas velocity is around 26 ft/s (8 m/s). The flue gas and solids are uniform ly distributed and at that g as velocity, there is virtually no erosion in the furnace roo f or the U- Be am m aterials; compar e this to the h ot cyclone de sign, which has experienc ed significant erosion at the cyclone entrance [66 to 85 ft/s(20 to 26 m/s)], the furnace roof, cyclone vo rtex finder [98 ft/s ( ~ 30 m/s)] and the c yclone barrel. B & W bubble cap nozzles are well designed, and at low load not much solids backsifting is experienced. No sootblowers are required in the convection pass. This eliminates main tenan ce and forced outages. Two-s tage solids collection provides better performance, especially carbon burn out, sulfur capture, and better h eat transfer. The solids collection efficiency is greater than 99.7%.
FUEL, LIMESTONE, AND SAND HANDLING SYSTEMS
FUEL, LIMESTONE, AND SAND HANDLING SYSTEMS
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Fuel Feed System
The fuel flo ws from fuel storage bunker s located in front of the boiler to gravimetric feeders. Each gravimetric feeder dischargers into a gravity feed chute. Air is injected at the base of each feed chute to ensure a positive flo w of fuel into the furnace. Fuel is fed into the pr imary zone o f the CFB furnace. The injection points are distributed across the widt h of the furnace f or unifo rm fuel feed. Furnace depth is designed for proper fuel mixin g within the bed.
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Limeston e Feed System
The limestone fl ows fro m the storage silo located adjacent to the boiler into gravimetric or volumetric feeders which mete r the quantity of limestone entering the unit. The feeders discharge via the feed chutes into the primar y zone of the furnace.
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Inert Bed Material Feed System
When a fuel with a low ash and lo w sulfur content is used, it may be necessary to provide supp lemental inert solid bed material such as sand to maintain inventory in the circulating bed. Increased limestone feed rate in mos t cases is not economical because, without substantial sulfation, limestone consu mptio n is high. Excess limestone, when calcined produces soft lime which breaks down quickly to very fine particles that p ass es to the bag hou se with little effect on the bed inventory.
EMISSIONS •
Sulfu r Capture
Sulfur capture in the CFB pro cess is achieved by adding limestone. The limestone is normally in the f orm of calcium carbonate (CaCO3) with impurities of magnesium carbonate (MgCO3), plus aluminium and iron oxide. Whe n the limeston e is added into the circulating fluidised bed at high tempera ture [1550 to 1650 °F (843 to 899 °C)], the CaCO 3 und ergo es endothermi c reactions to be com e CaO and C O2. Fuel sulfur oxidizes to becom e SO 2. In the presence of oxy gen, the CaO reacts exothermically w ith S O2 to form CaSO4 (calciu m sulfate), thus captu ring the sulfur. The calcium sulf ate is in the f orm o f solid material, which can be drained fr om the bed. Th e reactions are :
CaCO 3
-- - - --> CaO + CO2(endothermic reaction)
CaO + 1/2 0 2 + SO 2
--> CaSO 4 (exothermic reaction)
Sulfur capture is influenced by various factors such as fuel properties. Sulfur content, calcium to sulfu r mola r ratio, limeston e reactivity, furnace temperature, gas and solids residence time, and limes tone particle size.
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NO
x
Reduction
Low NO emiss ions are a major benefit of CFB boilers. When burnin g fuel in CFB boilers, approximate ly x
50 to 70% of the combustion air flow enters through the grid as primary air. The substoichiometric amount of air suppresses volatile nitrogen oxidation to NOx by creating a fuel-rich zone in the fuel devolatilization region. The secondary air is added further above the lower reducing zone. Since the fuel nitrogen is already tra nsforme d into molecular nitrogen, formation of NOx above this zone is controlled. The relatively low com bus tio n temperatu re [1550 to 1650 °F (843 to 899 °C)] also helps red uce N O x formation. NO emissio ns in CFB boilers are influenced by various factors including nitrogen and volatile matter in x
the fuel, furnace temperature, excess air, bed stoichiometry and limestone feed rate. Additional NO xreduction (say 40 to 60% of the CFB p rocess NOx) can be achieved by injecting ammo nia (NH3) either befor e or after the U-beam s. The factors influenci ng additional NOx reduction are NH3/NOx molar ratio, initial NO x Concentration, furna ce temperatu re, d egree of N H3 mixing and gas residence time.
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CO Emissions
CO emissions from a CFB boiler are generally very low. The formation of CO is due to incomplete combu stion and is a function of man y parameters such as bed temperature, excess air, type of fuel, no nunif orm fuel distribution, overfire air/gas mixing, and gas residence time in the furnace.
T B W C F B B o ile r
T B W C F B B o ile r O perab ility Strength Key Features
Key Benefits
1.
1.
Excellent turndo wn withou t auxiliary fuel (u p to 5:1).
. All in te rn al prim ary solids re cy cle a nd gravity feed second ary solids recycle with FD fan or PA fan air. ,
4.
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Reduce d opera ting costs at low load operation. Reduced auxiliary pow er consumption compare d to using high press ure blowers.
High solids co llection efficiency with two stages (>99.8%).
3.
Increased com bustion efficiency and reduced operating cost.
The en tire CFB unit has thin refractory installed.
4.
Reduced start up time and reduced operatin g costs. (Hot cyclone with thick refractory has prolo nge d start up).
Lower Maintenance/ Higher Reliability Key Features
Key Benefits
. All-i nt ern al p rim ary s olids re cy cle system (U-beam s) within a furnace.
1.
Avoid high mainten ance thick refractory (ex :hot cyclone) • Avoid forced outage concerns due to thick refractory failure, and special teams required to reinstall refractory.
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Low er velocities in the furnace, furnace exit, U-beams, and supe rheater
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Reduce d erosion potential due to low gas velocities. (Highv elocity gas/solids entering cyclone leads to erosion). • TBW's CFB had no erosion maintenance on U-beams after •several years of operation. • Reduced superheater erosion potential.
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No s ootblowers required in the convection pass
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Avoid maintenance and forced outage on convective surface failures caused by sootblowers
Circulating Fluidized-Bed B oiler Experience
Circulating Fluidized-Bed B oiler Experience (B&W, AE&E, B&W JV) Plant Loc ation
Capa city Ib/hr (t/hr)
Ultrapower
W est Enfield, Maine USA
220,000 (100)
Wood wa stes & wood chips
1986
Ultrapower
Jonesboro, Maine US A
220,000 (100)
Wood was tes & wood chips
1986
Sithe Energy
Ma rysville, Ca lifornia US A
164,000 (74.3)
Wood wa ste s
19"86
Lauhoff Grain Co.
Danville, Illinios US A
225,800 (102.4)
Bituminou s coal
1989
Ebensburg Pow er Co.
Ebensburg, 465,00 0 Penn sylvania USA (211)
High ash was te coal
1990
Pusan Dyeing Co.
Pusa n Republic of Korea
176,370 - (80)
Coal & hea vy oil
1991
Tha i Petrochemical Ind.
Rayong, Th ailand
286,6 00 (130)
Coal lignite, oil & gas
1994
Kanoria Chemicals & Industries Ltd.
Renukoot, India
231,48 0 (105)
High ash coal
1995
Southern Illinois University
Carbo ndale, Illinois, US A
120,000 (54.4)
Coal, petroleum coke & natural gas
1996
Los Angeles County San itation District (3 boilers)
Carson, California, US A
48,000 (21.8)
Sew age sludge
Customer
Fuel
Start-Up Da te
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Our Branch Offices :
MUMBAI
CHENNAI
NEW DELHI
Dhanra j M ahal, 2nd floor, Chhatrapati Shivaji Maharaj Marg, Near Gateway of India, C olaba, Mumbai 400 03 9 Tel. : 91-22-2045391, 2045324 Fax. : 91-22-2040859
610, Anna Salai, Chennai 600 006 Tel; : 91-44-8271891, 8272007 Telex : 041-7886 TMAX IN Fax. : 91-44-8277401
9, Commu nity Centre, Basant Lok New Delhi 110 057 Tel. : 91-11-6145319, 614532 6 Telex : 031-72013 TMA X IN Fax. : 91-11-6148679
Circulating Fluidized-Bed Boiler Experienc e
Circulating Fluidized-Bed Boiler Experienc e
