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boiler description ntpc shaktinagar
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BOILER
SABARI GIRISH N
SR. ENGINEER (O)
SESSION PLAN
Boiler fundamentals
Principle of Combustion
Classification of Boilers
Arrangement of main boiler
WHAT IS A BOILER?
“BOILER” means any closed vessel exceeding 22.75 litres in capacity which is used expressly for generating steam under pressure and includes any mounting or other fitting attached to such vessel, which is wholly or partly under pressure when steam is shut off. As per INDIAN BOILER REGULATIONS
COAL FLUE GAS
CO, CO2, H2, H2O, 02 AIR ASH
BOILER
STEAM
WATER
BOILER FUNDAMENTALS…
COMBUSTION EQUATIONS..
C +O2 CO2 33820 KJ/Kg
2C+O2 2CO 10200 KJ/Kg
2H+O2 H2O
S +02 SO2
COMBUSTION EQUATIONS..
AIR REQUIRED =4.31[(8/3)C – 8(H-0/8)-S]
ATMOSPHERIC AIR = N2 - 77% O2 - 23% by weight
N2 -79% O2- 21% by volume
EXCESS AIR FOR COMPLETE COMBUSTION- 15 TO 20%
REQUIREMENTS FOR GOOD COMBUSTION
3Ts temperature time Turbulance
COMBUSTION EFFICIENCYDesign of the boilerFuel usedSkill of obtaining combustion with minimum excess air ( CO monitoring)
EFFICIENCY CALCULATION METHODS
DIRECT METHOD IN-DIRECT METHOD
CLASSIFICATION OF BOILERS
BASED ON ARRANGEMENT
FIRE TUBE
WATER TUBE
CLASSIFICATION OF BOILERS
FIRING ARRANGEMENT FRONT FIRED CORNER /TANGENTIAL FIRED GRATE FIRED PULVERIZED FUEL FIRED
CIRCULATION NATURAL CIRCULATION FORCED CIRCULATION
CLASSIFICATION OF BOILERS
APPLICATION UTILITY BOILERS INDUSTRIAL BOILERS
CONSTRUCTION TOWER TYPE TWO PASS BOILERS
MANUFACTURERS CE-BHEL ANSOLDO LMZ
COMPONENTS OF A BOILER ECONOMISER BOILER DRUM DOWN COMERS WATER WALL PRIMERY SUPER HEATER PLATEN SUPER HEATER FINAL SUPER HEATER RE-HEATER BURNER OIL GUNS IGNITORS BUCK STAYS
STAGE-I
ECONOMISER
FORMS PART OF FEED WATER
CIRCUIT
PRE HEAT BOILER FEED WATER
RECOVERY OF HEAT FROM FLUE GAS
LOCATED IN BOTTOM OF REAR PASS
NO STEAM FORMATION
BOILER DRUM
TO SEPARATE WATER FROM STEAM
TO REMOVE DISSOLVED SOLIDS
TO PROTECT WATER WALLS FROM
STARVATION
ACTS AS TEMPORARY PRESSURE RESERVOIR
DURING TRANSIENT LOADS
WATER WALL
FORMS FURNACE ENCLOSURE
GENERATION OF STEAM
PROVIDES SEALING TO FURNACE
SUPER HEATER
RAISE STEAM TO HIGHER TEMPERATURE
ARRANGED IN 3 STAGES
LTSH LOCATED ABOVE ECONOMISER
RADIANT PENDENT TYPE (DIV PANEL)
ABOVE FURNACE
CONVECTIVE FINAL SUPER HEATER
ABOVE FURNACE IN CONVECTIVE PATH
RE HEATER RE HEAT THE STEAM FROM HP TURBINE TO 540 DEG
COMPOSED OF THREE SECTIONS
RADIANT WALL REHEATER ARRANGED IN FRONT &
SIDE WATER WALLS
REAR PENDANT SECTION ARRANGED ABOVE GOOSE
NECK
FRONT SECTION ARRANGED BETWEEN UPPER HEATER
PLATEN & REAR WATER WALL HANGER TUBES
BURNERS
32 COAL BURNERS & 16 OIL BURNERS IN ALL
IN CE TYPE BOILERS OF STAGE-II 500 MW
24 COAL BURNERS & 24 OIL GUNS IN STAGE-I
ANSALDO BOILER ARRANGED ON THE FRONT
IN 500 MW BOILERS BURNERS CAN TILTED +30
TO -30. DENPENDING ON THE REQUIREMENT
NO SUCH PROVISION IN STAGE- 1 BURNERS
IGNITORS
EACH GUN IS PROVIDED WITH AN IGNITOR
HIGH ENERGY ARC, EDDY CURRENT IGNITORS
OUT PUT VOLTAGE 2500V DC
SPARKS 4 SPARKS PER SECOND
DUTY CYCLE 15 MIN ON , 30 MIN OFF
CONTROL CIRCULATION PUMPS
THREE PUMPS PER BOILER(2X50%)
ASSIST IN CIRCULATING WATER THROGH
WATER WALL TUBES
EACH PUMP CAPACTY 2879.4 T/HR
DIFFERENTIAL PRESSURE 1.948 KSC
SPECIFIC GRAVITY .5993@362
DEG
BUCKSTAYS
MECHANICAL SUPPORT BEAMS
SUPPORTS BOILER ENCLOSURE
TO SAFE GUARD FURNACE
GEOMETRY , EXPECIALLY FURNACE
EXPLOSION /IMPLOSIONS
BOILER AUXILIARIES COAL FEEDERS MILLS PRIMARY AIR FANS SEAL AIR FAN FORCED DRAFT FANS WIND BOX SCANNER FAN AIR PRE HEATERS ESP INDUCED DRAFT FANS CHIMNEY SOOT BLOWERS
COMBUSTION
Constituents of coal (%) Carbon 36.54 Volatile matter
21.6 Moisture 10 Ash 32 Sulphure .38
500 MW RSTPS BOILER
MANUFACTURER BHEL-(CE DESIGN)
TYPE BALANCED DRAFT, DRY BOTTOM, SINGLE DRUM, CONTROLLED CIRCULATION PLUS, TILTING TANGENTIAL
NO OF MILL WITH OUT OIL SUPPORT
2 ADJACENT MILLS @ 50% OF CAPACITY
EXPLOSION/IMPLOSION CAPACITY
+660 OR -660 mmwc
VOLUME 14820 M3
SIZE 62.456MTR (FROM BA HOPPER TO FURNACE ROOF) X 15.289 X 18.034
TUBES OD -51MM THICKNESS-5.6MM, PITCH 63.5 DSGN PR 208.8 SA 210CWT 583.2 TONS
DRUM 22070X2130X1778 END THICKNESS 152.4mm CYCLONES 96 SA 299 WT 246 T, ( 224 T WITHOUT INTRNL)
CAPACITY 10 SEC FROM NORMAL TO LO-LO TRIP
SAFTEY VALVES DRUM -6 SUP HEATER 6 (2+4), CRH -4, HRH -8 (4+4)
TUBE LENGTH 350 KM approx( FOR 500 MW BOILER) , 58000 BUTT WELLDS approx
PARAMETERS
Flow MCR NCR
S H steam 1725 1384
RH steam 1537 1527
Feed water 1725 1527.3
Spray 22.7
Secondary 1464 1337
Primary air 558 477
Total Air 2021 1814
COAL( 4300 kcal/kg)
296 266
COMPARISONSL. NO
PARAMETER ST.-1 ST.-2
1 FIRING FRONT FIRED CORNER FIRED
2 CIRCULATION NATURAL CONTROLLED
3PF
TRANSPORTATIONPA FAN TO EACH MILL
COMMON PA FANS-2NOs.
4 OIL LFO/HFO LSHS or HFO
5 REHEATERS IN CONVECTIVE ZONEIN CONV. &
RADIATION ZONE
6 APHsCOMMON TO SEC. AND
PRIMARY AIRSEPARATE APHs
7 FLY ASHING CONTINUOUS(u#2 & 3) INTERMITTENT
8 BOILER CONTROL BMS FSSS
9 COAL MILL BALL AND RACE BOWL
Contd.SL. NO
PARAMETER ST.-1 ST.-2
10SH/RH TEMP.
CONTROLGAS BY PASS &
ATTEMPERATIONATTEMPERATION &
BURNER TILT
11 DOWN COMERS 7 6
12SECONDARY AIR
CONTROLNOT POSSIBLE POSSIBLE
13MILL CHANGE
OVERREQUIRE GUNS’
SUPPORT
ADJACENT MILL SUPPORT IS SUFFICIENT
14 IGNITORSREQUIRES LFO
SUPPORTHIGH ENERGY ARC.
NO OIL.
15 OIL GUN TIP Y J
16 AIRPRIMARY AIR,
SECONDARY AIRPA, SA, AUX. AIR, END
AIR, OVER FIRE
Contd.
SL. NO
PARAMETER ST.-1 ST.-2
17 FD FAN CONTROLVANE
CONTROLBLADE PITCH
CONTROL
18 PA FAN CONTROLVANE
CONTROLBLADE PITCH
CONTROL
SAFETY VALVES ( STAGE-II) BOILER DRUM 6 SPRING LOADED SUPER HEATER 2 SPRING LOADED, 4 ERVs CRH 4 SPRING LOADED HRH 4 SPRING LOADED, 4 ERVs
NO SET PR RESET PR %BLOWDOWN
B1 200 191 4
B2-B6 202- 206 192-196 5
SH 184 178 3
SH ERVs 180-182 176-178 4.8
CRH 55-56 53-55 3
HRH 48.5-49 47-47.5 3
HRH ERVs 47.5-48 46.6-47 1.97
SOOT BLOWING SYSTEM NO BLOWERS 104+34+4
WALL BLOWER LRSB TRAVEL 305 9200 mm NOZZLE DIA 26 32 mm BLOWING PRESSURE 12 12.5 ksc TIME 1.44 MIN (PER PAIR) RATE 833 KG/HR (PER PAIR) 293 CONSUMPTION 116.62 KG (PER PAIR)
3349 (PER GROUP)
ELECTRO STATIC PRECIPITATOR COLLECTION EFFICIENCY 99.9% TREATMENT TIME 33.33 SEC DUST CONCENTRATION 115mg / M3 (LIMIT) COLLECTING RAPPER FREQUECY 15- 2 RAPS/ HR EMITTING RAPPER FREQUECY 10 RAPS /HR HOPPERS 96 HOPPER CAPACITY 8HRS +10% HOPPER HEATERS 96X6 FIELD CURRENTS ( mA) 150 250 325 450 600 750 VOLTAGE 70 KV PEAK
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