boiler fundamental & water circulation system mdified

7/31/2019 Boiler Fundamental & Water Circulation System Mdified

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BOILER SPECIFICATIONS

Controlled circulation

Single drum

Top supported

Tangential corner fired

Riffle tubes

Balanced draught

Radiant reheat

Dry bottom

Furnace area 14770m3

Manufacturer BHEL


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BOILER COMPONENTS

BOILER DRUM,

DOWNCOMERS, CC PUMP,

FURNACE,(WATER WALL AND STEAMCOOLED WALL)

FUEL FIRING SYSTEM,(oilgun,ignitor,burner,burner tiltmechanism,scanner)

SADC,(secondary air damper control) WATER WALL TUBE OR RISER

ECONOMISER ,(THREE STAGE)

SUPER HEATER,(LTSH,DIVISIONAL


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REHEATER,SOOT BLOWER SYSTEM(WATERWALL,LRSB AND APH)

,BOTTOM ASHHOPPER(CRUSHER,REFACTORY,THROUGH SEAL)BOILER AUXILLARIESFANS(PA FANS,FD FANS, ID FANS)MILLING SYSTEM(MILL,RAW COALFEERDER,SEAL AIR FAN)AIR PREHEATER(SAPH,PAPH)ESP

ASH DISPOSAL SYSTEM.(DRY ASHSYSTEM,WET ASH SYSTEM


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BOILER DRUM

FUNCTIONS:-

SEPRATES WATER AND STEAM

REDUCED DISSOLVED SOLID CONTENTS OF STEAM

STORAGE OF WATER


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FURNACE

PROVIDES PROPER INSTTALATION, OPERATIONMAINTENANCE OF FUEL BURNING EQUIPMENTS

SUFFICIENT VOLUME FOR COMBUSTION

ADEQUATE REFRACTORIES & INSULATION


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ECONOMISER

LOCATED IN 2ND PASS BELOW LTSH.

PREHEATS BFW BEFORE GOING TO DRUM

SUPER HEATERS

LTSH(LOW TEMP. SUPER HEATER)

DIVISIONAL PANEL(PANEL SUPERHEATER)

PLATEN SUPERHEATER(FINAL)


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Principal of combustion


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Fuels :Gaseous fuelLiquid fuel solid fuel

Heat :

Air :Less amount of air will causeincomplete combustionExcess amount of air

will cause boiler losses

LDOHFO


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Three Ts for efficient combustion

1. Time2. Temperature3. Turbulence( proper mixing)

Combustion efficiency:1. design of boiler2. fuel used3. skill in obtaining combustion with minimum

amount of air


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REHEATERS

HEAT TRANSFER BY RADIATION & CONVECTION

COMPOSED OF FRONT & REAR PENDANT SECTION

AIR PREHEATERS

LOCATED IN FLUE GAS PASS AFTER ECONOMISER TOHEAT PRIMARY AND SECONDARY AIR


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BCW PUMP

BCW PUMP IS SINGLE STAGE, GLANDLESS

,SINGLE SUCTION DOUBLE DISCHARGE,

CENTRIFUGAL PUMP.


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BURNERS

COAL BURNERSOIL BURNERSAUX. AIR SUPPLY DAMPERSO/F AIR DAMPERSBURNER TILT MECHANISM

HEA IGNITORS

PROVIDED WITH ALL OIL BURNERS4 SPARKS /SEC,


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M

FT

FT

AB ELEVATION

CD ELEVATION

EF ELEVATION

GH ELEVATION

HOFCVHOTV

HORV

SHORTRECIRCULATION

HFOSUPPLY

LINE

HFORETURN

LINE

HFO SCHEME AT BOILER FRONT


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OIL GUN

ATOMISING

STEAM VALVE

HFO NOZZLEVALVE SCAVENGE

VALVE

AB ELEVATION

CD ELEVATION

EF ELEVATION

GH ELEVATION

ATOMISING STEAM SCHEME AT BOILER FRONT

OIL GUN CONNECTION


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Important phenomenon

Nucleate boiling

Film boiling

Water wall refile tubes


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condensor LP HEATERS

BFP ECO

B.DRUM

WATER WALL

DOWN COMER

HPH

URH

BRH

DEARETORST=40,P=-.9mm

p=


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Drum & drum internals


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ECO.SPECIFICATIONS

MATERIAL CARBON STEEL

SA210 GRA1,SA210 GRC

NO.OF COILS 76

OD OF TUBES(MM) 51

ACTUAL THICKNESS 5.6

DES.PR OF TUBES 207.4

DES.PR OF HEADERS 219.7


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M.S

FROM F.R.S

Economiser


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WATER WALLS SPECIFICATIONS

FW SW RW ROOFNUMBER 283 444 283 142

OD(MM) 51 51 51 57

D.THCKNESS 5.19 5.19 5.19 5.54

A.THICKNESS 5.6 5.1 5.1 5.1

JOINING BUTT BUTT BUTT BUTT

DES.PR OF TUBE 208.8 207.3 207.3 204.9

MAX.PR OF TUBE 197.0 197.3 197.3 192.3

DES.MET.TEMP 448 417 417 416


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WATER WALL HEADERS

INLET OUTLET

NO.OF HEADERS 4 5

OUTSIDE DIA(MM) 914.4 273DES THICKNESS(MM) 86 50

ACTUAL THICKNESS 89 45

DES PR.OF HEADERS 208.8 204

MAX.WORKING PR 197.0 192.2

MATERIAL SA-299 SA-106


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Bottom Ring

Header


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SH.SPECIFICATIONS

LTSH

STAGE-I

PLATEN

STAGE-II

PLATEN

STAGE-III

NO.OF

TUBES

708 444 456

OD(MM) 51.0 51.0 54.0

JOINING BUTT BUTT BUTT

MAX.STEM

TEMP

366(H)

467(P)

488 558

MAX GAS

TEMP

482(H)

512(P)

548 628


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M.S

FROM F.R.S

Sh 1


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M.S

FROM F.R.S

SH 2


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M.S

FROM F.R.S

Final SH


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RH SPECIFIFATIONS

STAGE-I STAGE-II

MAX.OPERATING PR 46.7 45.8

DESIGN PR 56.2 56.2

MAX.STEAMSIDE MT 397 566

MAX.GAS SIDE MT 460 612

OD(MM) 60.3 54.0

TOTAL NO.OF TUBES 248+254 644+92

JOINING BUTT BUTT


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M.S

FROM F.R.S

RH


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SH&RH HEADERS

SH RH

MAX.OPERATING PR

188.2 46.7

DESIGN PR 204 56.2

WEIGHT(KGS) 223000 117800


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RE HEATER CIRCUIT

NON DRAINABLE PORTION

DRAINABLE PORTION

UNIT 7 BOILER HYDRO TEST

M.S

FROM F.R.S


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RE HEATER CIRCUIT

NON DRAINABLE PORTION

DRAINABLE PORTION

UNIT 7 BOILER HYDRO TEST

M.S

FROM F.R.S


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SOOT BLOWING SYSTEM

88 Nos. of wall Blowers, 34 Nos of LRSBs and 4

Nos of APH Soot Blowers are provided in firstand second pass of boilers to remove Soot fromfurmace / SH coils and APH Elements.

Each wall blower is provided with a rotary &

traverse motor with associated gear boxarrangements for rotary & traverse motion of thelance

34 Nos of LRSBs are mounted on the water wallcovering SH and reheater sections to removeash dust from SH and RH coils


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Coal from Mines to Mills

MGR System

Coal Handling

Plant

RC Bunker Size = 200 mm to 25 mm

Feeder

Pulverizer/Mill Powdered Form


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Coal Feeders

Coal feeders is used to regulate the flow of coal from bunkethe pulverizerTypes of Coal Feeders:1. Volumetric Feeders2. Gravimetric Feeders

Coal Entry to feeder fro


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Coal Feeders

Gravimetric Coal Feeder : Feeding the Coal from Bunker to Pulverizer as per

requirement Leveling Bar

Specialized Belt Conveyer Amount of Coal entry controlled by the speed of the

Drive pulley Drive pulley connected through motor with variable

speed drive Either DC Motor or Motor with Magnetic clutch is

used


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Pulverization of Coal

Pulverization : It is a method by which the coal iscrushed to a fineness such that 70-80% passesthrough a 200 mesh sieve

Importance of Pulverization Coal firing:1. High Boiler Efficiency2. Ability to use high combustion air temp.3. Low Excess Air Requirement4. Ability to burn a wide variety of coals5. Better reaction to automatic control


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Low Speed Mill

Tube and Ball Mill Operate at 17 to 20 Rpm Coal Feed from both end of the Tube Small Ball of 30,40, 50 mm Sizes are used

Hot air blown to move coal to classifiers at twoelevations in boiler furnace

No Maintenance for long periods Better availability so no spare mill required Always a reserve of coal so there is no spark

produced between Steel balls Consumption of power is more High Foundation and Initial cost of Equipment


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Tube and Ball Mill

Ball and Tube Mill

RC Feeder

Drum Feeder

Coal entry to Drum

Classifiers Distributors2 No.

Classifiers 4 No.

Hot AirEntry


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Tube and Ball Mill

Steel Balls


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High Speed Mill

Impact Mills and Beater Mill Directly Coupled to the Motor 500 to 1000 Rpm Compact in Size

Less Power Consumption Rate of Wear of the grinding elements is High High Maintenance Cost


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Bowl Mill

Rollers

Coal Entry

Hot AirFlow fromPA Fan

ClassifiersTo burners


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Burners

Design consideration: Atomise the oil Properly shaped jet Combustion must be complete Excess air should be minimum Ready accessibility for repairs


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Burner Arrangement


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Flue Gas System


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Air Heaters

It is a heat transfer surface in which air temperature israised by transferring heat from other medium suchas flue gas.

These are used for heating the primary and secondaryair before entering the furnace.

Ad t


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Advantages1. Increase in boiler efficiency.

2. Stability of combustion increases by use of hot air.

3. Intensify and improved combustion.

4. Permitting to burn poor quality of coal.

5. High heat transfer rate in the furnace and hence lesser

heat transfer area requirement.

6. Less un burnt fuel particle in flue gas thus combustion

and both efficiency is improved.7. intensified combustion permits faster load variation

and fluctuations.


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Types of Air Heaters

1. Recuperative type

a. Tubular Reheater

b. Plate type Airheater

c. Steam Air Preheater

2. Regenerative typea. Ljungstrom type

b. Rothemuhle type


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Ljungstorm Airheater


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OVERVIEW OF AIR FLOW IN

TPP


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FURNACE

PRIMERY AIR HEATER

SECONDRY AIR HEATER MILLS

FD FAN A

PA FAN BPA FAN A

FD FAN B

ESPID FAN A

ID FAN B

HIMNEY

Atmospheric airAtmosphe

Atmospheric air

boiler fundamental & water circulation system mdified

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