10. SYSTEM DESCRIPTION
BOTTOM ASH GENERATED IS
EXTRACTED BY SCRAPPER CONVEYOR
AND GOES TO B.A. TRANSFER PIT
THROUGH CLINKER GRINDER. THE
SLURRY COLLECTED IN PIT IS
TRANSPORTED TO MAIN ASH SLURRY
PUMPS PIT BY B.A. TRANSFER PUMPS.
11. THREE METHOD OF ASH EVACUATION –
1. CONVENTIONAL FLUSHING SYSTEM
2. WET ASH SYSTEM
3. DRYASH SYSTEM
13. CONVENTIONAL FLUSHING
SYSTEM
ASH COLLECTION – DIRECT MIXING OF
ASH AND WATER
CYCLE TIME – APPROX. 10 MIN.
WATER CONSUMPTION – 2200 M3/Hr
14. WET ASH SYSTEM
ASH IS COLLECTED IN THE FORM OF
ASH SLURRY THROUGH WETTING HEAD
AND COLLECTING TANK AND GOES TO
THE SLURRY PUMP PIT.
15. TI e saI
laa[-na
vao@y
aUma
pmp
bafr
haÐpr
e ela
TI
P`aayamarI
klao@Tr
TOMk
saokNDrI
klao@Tr
TOMk
baoga
iflTr
eyar
vaaSar
vaoTIM
ga hoD
klao@T
r TOMk
saa[-
laonsa
r
ma
ao
Tr
21
16. NTPC
bafr haÐpr
BUFFER HOPPER
vaoTIMg
a hoD
WETTING
HEAD
klao@Tr
TOMk
COLLECTOR
TANK
eyar
vaaSar
AIR
WASHER
saa[-
laonsar
CYLINCER
P`aayamarI
klao@Tr
PRIMERY
COLLECTOR
saokN
DrIklao
@Tr
PRIME
RY
COLLE
CTOR
saIla
baa@s
a
Seal box
baoga
iflTr
TI e saI laa[-na
Vacuum header to v/pump
Vacuum from air washer to v /pump
19
To silo
Dry ash
To wet mode
T
o
d
r
y
m
o
d
e
Vacuum line
17. WET ASH SYSTEM
CONSTITUENTS OF THE SYSTEM :-
• WETTING HEAD
• AIR WASHER
• COLLECTING TANK
• PIPE LINES
• SEAL BOX
19. WET ASH SYSTEM
1. ASH COLLECTION – MIXING OF WATER AND ASH
BY SPRAY NOZZLES IN WETTING HEAD
2. IDLE CYCLE TIME – 5 MIN.
3. WATER CONSUMPTION - 100 M3/Hr. AT 35 MWC
4. MAIN PARTS-
a) COLLECTOR TANK – CAPACITY OF 12 Cu.M
b) WETTING HEAD – CAPACITY OF 54 T/Hr, 22 no.
OF SPRAY NOZZLE
c) AIR WASHER – 3 no. OF SPRAY NOZZLE FOR
CREATING FOG
20. DRY ASH SYSTEM
FROM ESP HOPPER ASH IS EVACUATED BY
VACUUM PUMP AND COLLECTED IN BUFFER
HOPPER, THEN IT IS TRANSPORTED VIA AIR
LOCK TANK TO SILO BY TRANSPORT AIR
FOR ASH UTILIZATION
21. DRY ASH SYSTEM
CONSTITUENTS OF THE SYSTEM :-
• PIPE LINES AND VALVES
• PRIMARY COLLECTOR TANK
• SECONDARY COLLECTOR TANK
• FILTER BAGS CHAMBER
• BUFFER HOPPER
• AIR LOCK TANKS
• 3 WAY VALVES
• ROTARY SEGREGATING VALVES
22. COMPRESSOR USED IN DRY FLY AND
WET MODE
INSTRUMENT AIR COMPRESSOR
TRANSPORT AIR COMPRESSOR
27. DRY ASH SYSTEM
1. IDLE CYCLE TIME – 10 MIN.
2. MAIN PARTS –
a) BUFFER HOPPER – CAPACITY OF 34.64
Cu.M
1. ASH COLLECTION – TRANSPORTATION OF ASH
IN DRY FORM TO SILO BY TAC
b) COLLECTORS – PRIMARY AND
SECONDARY COLLECTOR WITH CAPACITY OF
54 T/Hr EACH
c) ALT – CAPACITY OF 108 T/Hr
d) BAG FILTERS – 49 no. WITH PULSE
JETTING SYSTEM
28. – SCRAPPER CONVEYOR - 02 NOS ( 2 X 50%)
EACH UNIT
–CAPACITY – 15 T/HR
– CLINKER GRINDER-02 NOS (2 X 50% ) EACH
UNIT
29. STAGE-I FLY ASH SYSTEM
• 60 T/HR OF ASH IN EACH UNIT IS COLLECTED BY DRY FLY ASH
SYSTEM. NEW DRY FLY ASH SYSTEM IS PROVIDED ONLY IN UNIT
#2 AND UNIT #3 .
UNIT#1 HAS NO DRY ASH COLLECTING SYSTEM
• 56 ESP HOPPERS IN EACH UNIT
• 4 NOS OF COLLECTOR TANK
• 4 NOS OF AIR WASHER
• 4 NOS OF MECHANICAL EXHAUSTER
• 2 NOS OF I.A.C.
• DRY ASH IS COLLECTED AND SLURRY IS MADE BY WETTING
HEAD AND THROUGH TRENCH COLLECTED IN ASH PIT.
30. STAGE –II BOTTOM ASH SYSTEM
SYSTEM INCLUDES:
• SCRAPPER CONVEYOR – 02 NOS/UNIT (100%
EACH)
• CLINKER GRINDER – 02 NOS/UNIT (100% EACH)
• BA TRANSFER P/P – 02 NOS/UNIT (100% EACH)
• 05 SERIES FOR ASH DISPOSAL.
• ASH SLURRY PUMPS – 03 NOS / SERIES.
• SEAL WATER PUMPS FOR ASH SLURRY PUMP
GLAND SEALING.
• LP/HPASH WATER PUMPS.
31. STAGE –II DRY FLY ASH HANDLING
SYSTEM (500 MW)
• NO OF UNITS – 03 UNITS
• NO OF ESP PASSES – 04 / UNIT
• NO OF ESP HOPPERS – 24 / PASS
• TOTAL NO. OF ESP HOPPERS – 96
• NO OF VACUUM PUMP – 02/ PASS
32. STAGE # 1
200MW UNIT
Plant data for collection of ash-
Sr.no Description No. of
hopper per
boiler
Ash collection
rate per boiler
T/Hr
Holding
capacity storage
in Hrs. of max.
ash generation
1 Bottom ash hopper 1 12.85 4
2 Economizer hopper 4 3.22 8
3 Air heater hopper 4 3.22 8
4 ESP HOPPER
1 st row 8 39.61 12
2 nd row 8 9.002 12
3 rd row 8 1.39 12
4 th row 8 0.617 12
5 th row 8 0.335 12
6 th row 8 0.109 12
7 th row 8 0.061 12
5 Stack hopper 1 0.282 8
1) Bottom ash removal from each boiler unit = 15 T/Hr. continuously.
2) Fly ash removal from each boiler unit = 60 T/Hr. continuously
34. SILO
1. SILO CAPACITY - 400 MT EACH
2. SILO TRUCK LOADING -
a) WET ASH FOR ASH BRICK PLANTS
b) DRY ASH FOR CEMENT PLANTS
3. MAIN PARTS –
a) ROTORY FEEDER – CAPACITY OF 100 T/Hr
b) HMDC - CAPACITY OF 100 T/Hr, 16 no. OF
NOZZLES FOR 45 Cu.M/Hr OF WATER SPRAY
c) AERATION BLOWER- CAPACITY OF 76 Cu.M/Hr
AT 3 MWC
d) BAG FILTERS – 108 no. WITH PULSE JETTING
SYSTEM
36. ASP
5A 5B
ASP
4A
3A 3B
2A 2B
4B
1A 1B
Ash slurry
pit no. 1
Ash slurry
pit no. 2
SCHEMATIC FLOW DIAGRAM FROM STAGE#2 P/P HOUSE
ASP
5C
4C
3C
2C
1C
TO OLD DYKE
LP Water header for flushing.
450 NB pipe line
TO
BPH
From RWL-BPH
37. ASH UTILISATION
• Cement, Asbestos – Cement products &
Concrete manufacturing industries
• Land development
• Road embankments construction
• Ash Dyke Raising
• Building Products such as Bricks/ blocks/tiles,
• Reclamation of coal mine
• As a soil amender and source of micro –
nutrients in agriculture.
38. CONSTRAINTS
• CORROSION OF METAL PARTS DUE TO POOR QUALITY OF
COAL BURNED
• DIFFICULTY IN DETECTION OF SUCTION SPOT DURING
LOW VACCUM
• FREQUENT GLAND SEAL LEAKAGE AND BODY LEAKAGE
IN VACCUM PUMPS
• LESS AVAILABILITY OF TAC LINE DUE TO FREQUENT
COUPLING LEAKAGE AND DAMAGE OF RSV DISC
• FREQUENT DAMAGE OF BAG FILTERS
39. CONSTRAINTS
BOTTOM PORTION OF PIPE GETS ERRODED OVER
THE PERIOD OF TIME.
RATE OF EROSION DEPENDS ON MANY FACTORS
LIKE ASH- PARTICLE SIZE, CHEMICAL
COMPOSITION, LINE PRESSURE, SLURRY
CONCENTRATION, VELOCITY ETC.
RATE OF EROSION OF ALL ASH LINES DIFFER DUE
TO CHANGE IN ASH SLURRY CONCENTRATION, IT
CARRIES.
• LESS UTILISATION OF ASH DUE TO LESSER ASH
TRUCKS AVAILABLITY
40. CONSTRAINTS
BOTTOM PORTION OF PIPE GETS ERRODED OVER THE
PERIOD OF TIME.
RATE OF EROSION DEPENDS ON MANY FACTORS LIKE ASH-
PARTICLE SIZE, CHEMICAL COMPOSITION, LINE PRESSURE,
SLURRY CONCENTRATION, VELOCITY ETC.
RATE OF EROSION OF ALL ASH LINES DIFFER DUE TO
CHANGE IN ASH SLURRY CONCENTRATION, IT CARRIES.
• LESS UTILISATION OFASH DUE TO LESSER ASH TRUCKS
AVAILABLITY
