COKING COAL :
These coals, when heated in the absence of air, form
coherent beads, free from volatiles, with strong and porous
mass, called coke.
- These have coking properties
- Mainly used in steel making and metallurgical
industries
- Also used for hard coke manufacturing
SEMI COKING COAL :
These coals, when heated in the absence of air, form
coherent beads not strong enough to be directly fed into the
blast furnace. Such coals are blended with coking coal in
adequate proportion to make coke.
- These have comparatively less coking properties than
coking coal
- Mainly used as blend-able coal in steel making,
merchant coke manufacturing and other metallurgical
industries
NON-COKING COAL :
These are coals without coking properties.
- Mainly used as thermal grade coal for power generation
- Also used for cement, fertilizer, glass, ceramic,
paper, chemical and brick manufacturing, and for other
heating purposes
HARD COAL :
Hard coke is formed from coking / semi-coking coal through
the process of carbonisation.
- Mainly used in metallurgical industries
- Also used in industrial plants utilising furnaces
WASHED AND BENEFICIATED COAL :
These coals have undergone the process of coal washing or
coal beneficiation, resulting in value addition of coal due
to reduction in ash percentage.
- Used in manufacturing of hard coke for steel making
- Beneficiated and washed non-coking coal is used mainly
for power generation
- Beneficiated non-coking coal is used by cement, sponge
iron and other industrial plants
MIDDLINGS :
Middlings are by-products of the three stage coal washing /
beneficiation process, as a fraction of feed raw coal.
- Used for power generation
- Also used by domestic fuel plants, brick manufacturing
units, cement plants, industrial plants, etc.
REJECTS :
Rejects are the products of coal beneficiation process after
separation of cleans and / or middlings, as a fraction of
feed raw coal.
- Used for Fluidized Bed Combustion (FBC) Boilers for
power generation, road repairs, briquette (domestic fuel)
making, land filling, etc.
CIL COKE / LTC COKE :
CIL Coke / LTC Coke is a smokeless, environment friendly
product of the Dankuni Coal Complex, obtained through low
temperature carbonisation.
- Used in furnaces and kilns of industrial units
- Also used as domestic fuel by halwais, hotels, etc.
COAL FINES / COKE FINES :
These are the screened fractions of feed raw coal and LTC
coke / CIL Coke respectively, obtained from the Dankuni Coal
Complex and other coke oven plants.
- Used in industrial furnaces as well as for domestic
purposes
TAR / HEAVY OIL / LIGHT OIL / SOFT
PITCH :
These are products from Dankuni Coal Complex using low
temperature carbonisation of non-coking coal in vertical
retorts.
- Used in furnaces and boilers of industrial plants as
well as power houses, oil, dye, pharmaceutical industries,
etc.
GRADATION OF COAL
|
A. COKING COAL |
|
Grade |
Parameter |
| Steel – I |
Ash not
exceeding 15% |
| Steel –
II |
Ash
exceeding 15% but not
exceeding 18 % |
| Washery –
I |
Ash
exceeding 18% but not
exceeding 21 % |
| Washery –
II |
Ash
exceeding 21% but not
exceeding 24 % |
| Washery –
III |
Ash
exceeding 24% but not
exceeding 28 % |
| Washery –
IV |
Ash
exceeding 28% but not
exceeding 35 % |
|
B. SEMI COKING COAL |
|
Grade |
Parameter |
| Semi
Coking – I |
Ash +
moisture not exceeding 19 % |
| Semi
Coking – II |
Ash +
moisture exceeding 19 % but
not exceeding 24 % |
|
C. NON-COKING COAL |
|
Grade |
UHV RANGE
(KCALS/KG) |
| A |
Exceeding
6200 |
| B |
Exceeding
5600 but not exceeding 6200 |
| C |
Exceeding
4940 but not exceeding 5600 |
| D |
Exceeding
4200 but not exceeding 4940 |
| E |
Exceeding
3360 but not exceeding 4200 |
| F |
Exceeding
2400 but not exceeding 3360 |
| G |
Exceeding
1300 but not exceeding 2400 |
|
D. HARD COKE |
|
Grade |
Ash %
|
| By
Product Premium |
Not
exceeding 25 % |
| By
Product Ordinary |
Exceeding
25 % but not exceeding 30 % |
| Beehive
Premium |
Not
exceeding 27 % |
| Beehive
Superior |
Exceeding
27 % but not exceeding 31 % |
| Beehive
Ordinary |
Exceeding
31 % but not exceeding 36 % |
SUITABILITY OF COAL
|
E. HARD COKE |
|
Industry |
Type of
Coal Required |
| Steel
making |
Coking and
semi-coking coal, direct
feed and washed; blendable
coal; low ash % Assam and
Ranigunj coal |
| Steel
making, sponge iron industry |
Non-coking
coal of high Initial
Deformation Temperature (IDT)
(>1200 degrees Celcius) |
| Cokeries /
coke oven plants |
Coking and
semi-coking coal |
| Briquette
making / domestic fuel
making |
Semi-coking
and non-coking coal;
middling & rejects of
washeries |
| Special
Smokeless Fuel (SSF) |
Semi-coking
coal of Coking Index 8 – 10 |
| Power
sector |
Non-coking
coal; middlings of coking
coal washeries; washed coal
of non-coking coal washeries |
| Cement
sector |
Non-coking
coal; middlings of coking
coal washeries |
| Glass and
potteries |
Long Flame
non-coking coal |
| Cast iron
castings |
Hard coke
|
| Steel
castings |
Non-coking
coal |
| Bricks |
Non-coking
coal; middlings of coking
coal washeries |
| Old boilers |
Superior
grades of non-coking coal |
| Halwais,
domestic use, hotels, etc. |
Non-coking
coal; CIL Coke / LTC Coke |
