Boiler Fundamental & Water Circulation System Mdified

BOILER SPECIFICATIONS 

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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 STEAM COOLED WALL) FUEL FIRING SYSTEM,(oil gun,ignitor,burner,burner tilt mechanism,scanner) SADC,(secondary air damper control) WATER WALL TUBE OR RISER ECONOMISER ,(THREE STAGE) SUPER HEATER,(LTSH,DIVISIONAL

•REHEATER, •SOOT BLOWER SYSTEM(WATER WALL,LRSB AND APH) •,BOTTOM ASH HOPPER(CRUSHER,REFACTORY,THR OUGH SEAL) •BOILER AUXILLARIES •FANS(PA FANS,FD FANS, ID FANS) •MILLING SYSTEM(MILL,RAW COAL FEERDER,SEAL AIR FAN) •AIR PREHEATER(SAPH,PAPH) •ESP •ASH DISPOSAL SYSTEM.(DRY ASH SYSTEM,WET ASH SYSTEM

BOILER DRUM FUNCTIONS:-

SEPRATES WATER AND STEAM REDUCED DISSOLVED SOLID CONTENTS OF STEAM

STORAGE OF WATER

FURNACE 

PROVIDES PROPER INSTTALATION, OPERATION MAINTENANCE OF FUEL BURNING EQUIPMENTS



SUFFICIENT VOLUME FOR COMBUSTION



ADEQUATE REFRACTORIES & INSULATION

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)

Principal of combustion

Fuels : Gaseous fuel Liquid fuel  solid fuel

Heat :

•LDO •HFO

Air : Less amount of air will cause incomplete combustion Excess amount of air will cause boiler losses

Three T’s for efficient combustion 1. Time 2. Temperature 3. Turbulence( proper mixing)

Combustion efficiency: 1. design of boiler 2. fuel used 3. skill in obtaining combustion with minimum amount of air

REHEATERS HEAT TRANSFER BY RADIATION & CONVECTION

COMPOSED OF FRONT & REAR PENDANT SECTION

AIR PREHEATERS LOCATED IN FLUE GAS PASS AFTER ECONOMISER TO HEAT PRIMARY AND SECONDARY AIR

BCW PUMP • BCW PUMP IS SINGLE STAGE, GLANDLESS ,SINGLE SUCTION DOUBLE DISCHARGE, CENTRIFUGAL PUMP.

BURNERS COAL BURNERS OIL BURNERS AUX. AIR SUPPLY DAMPERS O/F AIR DAMPERS BURNER TILT MECHANISM

HEA IGNITORS PROVIDED WITH ALL OIL BURNERS 4 SPARKS /SEC,

HFO SCHEME AT BOILER FRONT HOFCV

HOTV FT

AB ELEVATION CD ELEVATION EF ELEVATION

M

GH ELEVATION SHORT RECIRCULATION

FT

HORV HFO SUPPLY LINE

HFO RETURN LINE

ATOMISING STEAM SCHEME AT BOILER FRONT AB ELEVATION

CD ELEVATION

EF ELEVATION

GH ELEVATION

OIL GUN CONNECTION

HFO NOZZLE VALVE

ATOMISING STEAM VALVE

SCAVENGE VALVE

OIL GUN

Important phenomenon 

Nucleate boiling



Film boiling

Water wall refile tubes

Flow chart of WCS condensor

LP HEATERS

DEARETORS

T=40,P=-.9mm

BFP

HPH

ECO

p=
B.DRUM

DOWN COMER

URH

BRH

WATER WALL

Drum & drum internals

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

M.S

FROM F.R.S

Economiser

WATER WALLS SPECIFICATIONS FW

SW

RW

ROOF

NUMBER

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

417

417

416

448

WATER WALL HEADERS INLET

OUTLET

NO.OF HEADERS

4

5

OUTSIDE DIA(MM)

914.4

273

DES 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

Bottom Ring Header

SH.SPECIFICATIONS LTSH STAGE-I 708

PLATEN STAGE-II 444

PLATEN STAGE-III 456

51.0

51.0

54.0

JOINING

BUTT

BUTT

BUTT

MAX.STEM TEMP MAX GAS TEMP

366(H) 467(P) 482(H) 512(P)

488

558

548

628

NO.OF TUBES OD(MM)

M.S

FROM F.R.S

Sh 1

M.S

FROM F.R.S

SH 2

M.S

FRM F.R.S

LTSH

M.S

FROM F.R.S

Final SH

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

M.S

FROM F.R.S

RH

SH&RH HEADERS SH

RH

MAX.OPERATI 188.2 NG PR

46.7

DESIGN PR

56.2

204

WEIGHT(KGS) 223000

117800

M.S

FROM F.R.S

RE HEATER CIRCUIT NON DRAINABLE PORTION DRAINABLE PORTION UNIT 7 BOILER HYDRO TEST

M.S

FROM F.R.S

RE HEATER CIRCUIT NON DRAINABLE PORTION DRAINABLE PORTION UNIT 7 BOILER HYDRO TEST

SOOT BLOWING SYSTEM 88 Nos. of wall Blowers, 34 Nos of LRSB’s and 4 Nos of APH Soot Blowers are provided in first and second pass of boilers to remove Soot from furmace / SH coils and APH Elements.  Each wall blower is provided with a rotary & traverse motor with associated gear box arrangements for rotary & traverse motion of the lance  34 Nos of LRSBs are mounted on the water wall covering SH and reheater sections to remove ash dust from SH and RH coils 

Coal from Mines to Mills MGR System Coal Handling Plant RC Bunker

Size = 200 mm to 25 mm

Feeder Pulverizer/Mill Powdered Form

Coal Feeders

Coal feeders is used to regulate the flow of coal from bunker the pulverizer Types of Coal Feeders: 1. Volumetric Feeders 2. Gravimetric Feeders Coal Entry to feeder from

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

Pulverization of Coal Pulverization : It is a method by which the coal is crushed to a fineness such that 70-80% passes through a 200 mesh sieve Importance of Pulverization Coal firing: 1. High Boiler Efficiency 2. Ability to use high combustion air temp. 3. Low Excess Air Requirement 4. Ability to burn a wide variety of coals 5. Better reaction to automatic control

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 two elevations 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

Tube and Ball Mill RC Feeder Classifiers 4 No. Drum Feeder Classifiers Distributors 2 No. Hot Air Entry

Ball and Tube Mill Coal entry to Drum

Tube and Ball Mill

Steel Balls

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

Bowl Mill Coal Entry

Hot Air Flow from PA Fan

Classifiers To burners Rollers

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

Burner Arrangement

Flue Gas System

Air Heaters It is a heat transfer surface in which air temperature is raised by transferring heat from other medium such as flue gas. These are used for heating the primary and secondary air before entering the furnace.

Advantages 1. 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.

Types of Air Heaters 1. Recuperative type a. Tubular Reheater b. Plate type Airheater c. Steam Air Preheater 2. Regenerative type a. Ljungstrom type b. Rothemuhle type

Ljungstorm Airheater

OVERVIEW OF AIR FLOW IN TPP

FURNACE

CHIMNEY SECONDRY AIR HEATER

FD FAN A FD FAN B ID FAN A

ID FAN B

Atmosphe ESP ric air

MILLS

PRIMERY AIR HEATER

PA FAN A

PA FAN B

Atmospheric Atmosphe air ric air