Boiler Fundamental & Water Circulation System

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july 9,2008


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1-Combustion

2. Boiler & Classification

3.Arrangament of main components

Boiler Fundamental

Water Circulation System

1-Types of circulation system

2-Nucleate ,film boiling ,ww rifiled tubes

3-Flow Chart4-Economiser Operation

5-Drum &Drum internals

CONTENTS


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November 9,2006


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Principal of combustion


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Fuels :Gaseous fuelLiquid fuel solid fuel

Heat :

Air :Less amount of air will cause

incomplete combustionExcess amount of air

will cause boiler losses

HEALDOHFO


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Three Ts for efficient combustion

1. Time

2. Temperature

3. Turbulence( proper mixing)

Combustion efficiency:1. design of boiler2. fuel used

3. skill in obtaining combustion with minimum

amount of air


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Boiler :

Boiler is device for generating steam for power,

processing, or heating purpose

Classification:

1. Tube contents

a .water tube

b. fire tube

2.Firinga. tangential

b.center

Contd..


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4. Use

a. utility

b.industrial

3.Circulation

a. natural

b. controlled

c. combined


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ARRANGEMENT OF MAIN

BOILER (STEAM GENERATOR)

A STEAM GENERATOR IS A COMPLEX INTEGRATIONOF THE FOLLOWING ACCESSORIES:

* ECONOMISER * LTSH

* BOILER DRUM * DIV PANEL

* DOWN COMERS * PLATEN SH

* CCW PUMPS * REHEATER

* BOTTOM RING HEADER * BURNERS

* WATER WALLS * APHs


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SUPPORTING STRUCTURES

MAIN COLUMNS: SUPPORTS DRUM, SHs, RH, ECO,

APH

BURNERS & GALLERIES AT VARIOUS LEVELS

AUX COLUMNS: SUPPORTS THE BOILER PLATFORM

AND OTHER DUCTS


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GALLERIES & STAIRWAYSGALLERIES & STAIRWAYS

COMBUSTION & HEAT RECOVERYCOMBUSTION & HEAT RECOVERY

AREAS FOR PROPER APPROACHAREAS FOR PROPER APPROACH

STAIRWAYS ARE PROVIDED ON BOTHSTAIRWAYS ARE PROVIDED ON BOTHTHE SIDES OF BOILERTHE SIDES OF BOILER

ALL THE FLOORS ARE COVEREDALL THE FLOORS ARE COVEREDWITH FLOOR GRATINGS FORWITH FLOOR GRATINGS FOR

WALKWAYSWALKWAYS


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FURNACEFURNACE

PROVIDES PROPER INSTTALATION, OPERATIONPROVIDES PROPER INSTTALATION, OPERATION

MAINTENANCE OF FUEL BURNING EQUIPMENTSMAINTENANCE OF FUEL BURNING EQUIPMENTS

SUFFICIENT VOLUME FOR COMBUSTIONSUFFICIENT VOLUME FOR COMBUSTION

ADEQUATE REFRACTORIES & INSULATIONADEQUATE REFRACTORIES & INSULATION


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BOILER DRUMBOILER DRUM

FUNCTIONS:-

SEPRATES WATER AND STEAM

REDUCED DISSOLVED SOLID CONTENTS OF STEAM

STORAGE OF WATER


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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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REHEATERS

HEAT TRANSFER BY RADIATION & CONVECTION

COMPOSED OF FRONT & REAR PENDANT SECTION

AIR PREHEATERS

LOCATED IN FLUE GAS PASS AFTER ECONOMISER


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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, 12 J /SPARK,120 V


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November 9,2006

W t i l ti t (WCS)


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BOTTOM RNG HDR& Z-PANEL 1ST PASS W.W

1ST PASS W.W O/L HDRS ROOF I/L HEADER

2ND PASS UPPER C-HDR 2nd PASS LOWER C-HDRS

LTSH I/L HEADER LTSH O/L HEADER

D.P.I/L HEADER D.P.O/L HEADER

S.H. HEADER R.H.HEADER2ND PASS ROOF O/L HDR(REAR ECONOMISER

M.S

H.

R.

HC.R.H

FROM F.R.S

Water circulation system (WCS):


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Circulation ratioThe ratio of the weight of water to the weight of steam

In mixture leaving the absorption surfaces is called

Circulation ratio

Various types of WCS of boiler:

1. Natural circulation system2. Controlled circulation system

3. Combined circulation system


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Natural circulation system

thermo-siphon principal used for pressure up to 140 kg/cm2 circulation ratio = 14 to 16


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2. Controlled circulation system:

use of controlled circulation pump used for pressure up to 194kg/cm2 (sub critical pr.) circulation ratio=6-9


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3.Combined circulation system:Circulation ratio=2

No use of drumUse of controlled circulation pumpUse for pressure above 200kg/cm2.


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Important phenomenonImportant phenomenon Nucleate boilingNucleate boiling

Film boilingFilm 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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ECONOMISER OPERATION

Improved efficiency

Counter flow arrangement of flue gasses & water

Role of soot blowers

INCORPORATION OF STOP &NON RETURN VALVE

AVOID STEAMING

PRECAUTION:-


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WATER WALLS

Tangential arrangement of tubesTangential arrangement of tubes

Nucleate boilingNucleate boiling

Absorb around 50%heat released by combustionAbsorb around 50%heat released by combustion of fuelof fuel

Drum & drum internals


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Drum & drum internals


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Boiler Fundamental & Water Circulation System

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