COKE MAKING
BY
SATRUGHNA NAYAK
What is coke
• Coke is a hard, porous mass containing
carbon and ash, by heating coal in a closed
chamber in the absence of air (destructive
distillation) to drive out the volatile matter.
Coal Vs Coke(BF)
Why not Coal Why coke
• High crushing strength
• Its poor crushing strength. Burden support
• Poor combustibility.
• High combustibility
• Presence of volatile matter. Fuel for heat generation
Reducing agent
• Excessive fines. • No volatile matter
• High Swelling property. Furnace pressure control
• Limited fines
• Moisture, Volatile matter, Furnace permeability
Ash, carbon • Negligible swelling
Less fines generation
• Ash and Carbon
Blending of coal
FROM R.M.H.
BINS 1 2 3 4 5 6 7 8 9 10
WEIGH FEEDERS
TO CRUSHER HOUSE
Best Coal required for coke-making-Bituminous Grade
Moisture 9%~12% (10% as basis for calculation)
Ash (dry basis): 10.64% (max.)
Volatile matter (dry basis): 24%~26% (25% as basis for calculation)
Sulphur: 0.6~0.7% (max.)
8
Belt Magnet & Magnetic Separator
COAL CRUSHING
Fraction below 50% (Max.) FROM BLENDING BINS
0.5mm:
Fraction below 90% (Min.)
3.15mm:
COLLECTING
BIN
APRON FEEDER
COLLECTING PRIMARY CRUSHER
BIN
APRON FEEDER
SECONDRY CRUSHER
TO COAL TOWERS
10
COAL CRUSHER HAMMER TIPS – COKE PLANT
COAL FILLING
FROM CRUSHERS
COAL TOWER
SCP#1
12
STAMPING PROCESS
t/Oven 42
Coal cake (t/Oven)
t/m3 1.0
Bulk density of coal cake
(dry) t/m3
COKE OVEN BATTERY
OVEN TOP
HEATING
CHAMBER
DOOR
OVEN TOP
OVEN
OVEN
OVEN
HC H HC H
C C
REGENERATOR
CHARGING PROCESS
SCP MACHINE
OVEN
16
HPLA VALVE IN THE GOOSE NECK OF THE AP OF THE CHARGING OVEN
HEATING
CHAMBER
OVEN
DUMMY
WALL OVEN OVEN OVEN OVEN
REGENERATOR
OVEN WALL
REGENERATOR
WASTE GAS
GAS
COAL CARBONISATION
HEATING HEATING HEATING
HEATING
CHAMBER OVEN CHAMBER OVEN CHAMBER OVEN CHAMBER
Coal cake is Heated in absence of air for 26 hours
Coke oven (CO) gas is generated.
26
MOVEMENT OF PLASTIC LAYERS
Semi-Coke Layer
Melting Layer
Coal Layer
Wall
Research & Development
Semi
Coal
coke
Plastic
mass
Coke
Steam Tar
condens &
Just after ation gas
charging
Steam Plastic
formation After mass, Few
moisture semi-coke hours
removal & coke after
charging
Heating
Wall
Only semi- Coke
coke & coke ( At the time
of pushing)
Temperature ( degrre centigrade) Activiteis
375-475 Destructive distillation
Evaluation of volatile product
475-600 Tar formation,
Swelling -as gas and condensable
vapour are entrapped in plastic
mass,
Plasticity –decreases,
Semi coke formation
600-1100 Coke stabilization
Contraction of coke
Hydrogen removed
PUSHING PROCESS
SCP MACHINE
OVEN COKE GUIDE CAR
COKE CAR
32
PUSHING OPERATION
SCP
Even Distribution of Hot Coke in Quench Car
Hot coke being taken to Quenching Tower
QUENCHING PROCESS
QUENCHING
BATTERY STATION
Q.L.
36
COKE DUMPING AND DISPATCH
BATTERY
QUENCHING
STATION
Q.L.
WHARF WHARF
TO BLAST FURNACE
37
FUEL AND COMBUSTION
COMPOSITION OF BY-PRODUCT GASES USED AS FUEL
B.F.Gas C.O. Gas L.D. Gas
CO2 14-16 3-4 3-4
O2 <1 <1 1.0
CO 22-24 7-8 50-55
H2 4-6 52-54 4-5
CH4 NIL 20-22 NIL
CnHm NIL 3-4 NIL
N2 52-54 5-6 40-45
CV 850-900 4100-4300 1650-1700
Sp.Gr. 1.03 0.44 1.08
Coke properties
Moisture ~3.5%
Ash (dry basis) 14% (max)
Volatile matter (dry basis) 1% (max)
Sulphur 0.8% (max)
M40 81 (min)
M10 6.5 (max)
CSR 65 (min)
CRI 22 ~ 25
Types of coke
BF COKE-30-80MM
NUT COKE-10-30MM
BREEZ COKE-Below 10mm
CRUDE GAS GENERATION AND DISPATCH
EACH BLOCK OVENS HAS CONNECTED WITH A GAS COLLECTING MAIN
EACH OVEN CHARGED WITH 40 TONES WET COAL CAKE
GAS
HOLDER
BY PRODUCT
HOT STRIP COLD ROLL POWER PLANTS PLANT
MILLS MILLS
EXHAUSTER
FLARE A HOUSE
FLARE B
GAS COLLECTING (G.C.) MAIN
COKE PLANT 42
C.O.CRUDE GAS GENERATION FROM OVEN AND FLOW PATH
EACH OVEN CONNECT WITH INDIVISUAL ASCENSION PIPE
AND ELBOW WITH COMMON GAS COLLECTING MAIN
A.P. CAP
AP TROUGH
FLUSHING LIQUOR
HPLA
ELBOW
ASCENSION PIPE ISOLATING VALVE
( A.P. ) (I.V.)
GAS COLLECTING MAIN
MINISTAND
(G. C. MAIN)
C.O. CRUDE GAS
SUCTION HOLE
TO BY PRODUCT PLANT
OVEN
COAL CAKE COAL CAKE
40 TONS
COKE PLANT 43
BATTERY OPERATION
ACCENSSION PIPE 44
BATTERY OPERATION
BATTERY OPERATION
C.O.CRUDE GAS GENERATION FROM OVEN AND FLOW PATH
FOUL GAS MAIN
TO BPP
-VE PRESSURE
G C MAIN CONTROLLER
TO TAR & LIQUOR
CROSS OVER MAIN PUMP HOUSE
12.5MMWC
G C MAIN
COKE PLANT 47
Sl No. PARAMETERS
Battery Specification Unit Value
1 Number of Oven Chambers (4 x 44 ovens) Nos 176
2 Volume of coal cake (m3/Oven) m3/Oven 36.5
3 Bulk density of coal cake (dry) t/m3 t/m3 1.0
4 Charge per oven chamber (dry) t/m3 t/m3 36.5
5 Coking Time (Wet Quenching) hrs Hrs 26.5
6 Coking Time (Dry Quenching) hrs Hrs 25.5
7 Coke Production/Oven T 27.74
8 Annual Operating days of coke oven Days 365
9 Moisture in coal charge (%) % 10
10 Gas Yield (m3/t dry coal) m3/t dry coal 320
11 Coke Yield (%) % 76
12 CV of Mixed Gas for coke oven heating (Kcal/m3) Kcal/m3 1000~1050
CSN
Any Question
