Coal and Coke

Question: Differentiate between Coal and Coke:- Coal Coke 1. It is a Primary Fuel. 1. It is a Secondary Fuel. 2. It is a readily combustible black or brownish-black sedimentary rock. 2. Coke from coal is grey, hard, and porous. Coke is a solid carbonaceous leftover derived from destructive distillation of low-ash, low- sulfur bituminous coal. 3. The energy density of coal is roughly 24 Mega joules per kilogram and in terms of kWh the energy density of coal is 6.67 kW*hours/kg 3. Coke has Better Calorific Value than coal. The energy density of coke is roughly 24.8 million Btu/ton (29.6 MJ/kg). 4. Coal usually contains a considerable amount of incidental moisture, which is the water trapped within the coal in between the coal particles. Coals are usually mined wet and may be stored wet to prevent spontaneous combustion, so the carbon content of coal is quoted as both a 'as mined' and on a 'moisture free' basis. 4. The volatile constituents of the coal, including water, coal-gas and coal-tar, are driven off by baking in an oven without air at temperatures as high as 1,000 °C (1,832 °F) so that the fixed carbon and residual ash are fused together. In that scene Coke has better yield of energy as volatile compounds have been removed. 5. Coal has 0.4 times greater density as Coke has. 5. Coke typically has a specific gravity between 1.85 and 1.9. It is highly porous, and a mass of coke has 40% greater volume than the equivalent mass of coal. 6. Low quality coals, like 6. Since the smoke-producing

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Transcript of Coal and Coke

Question:Differentiate between Coal and Coke:-

Coal Coke1. It is a Primary Fuel. 1. It is a Secondary Fuel.2. It is a readily combustible black or brownish-black sedimentary rock.

2. Coke from coal is grey, hard, and porous. Coke is a solid carbonaceous leftover derived from destructive distillation of low-ash, low-sulfur bituminous coal.

3. The energy density of coal is roughly 24 Mega joules per kilogram and in terms of kWh the energy density of coal is 6.67 kW*hours/kg

3. Coke has Better Calorific Value than coal. The energy density of coke is roughly 24.8 million Btu/ton (29.6 MJ/kg).

4. Coal usually contains a considerable amount of incidental moisture, which is the water trapped within the coal in between the coal particles. Coals are usually mined wet and may be stored wet to prevent spontaneous combustion, so the carbon content of coal is quoted as both a 'as mined' and on a 'moisture free' basis.

4. The volatile constituents of the coal, including water, coal-gas and coal-tar, are driven off by baking in an oven without air at temperatures as high as 1,000 °C (1,832 °F) so that the fixed carbon and residual ash are fused together.In that scene Coke has better yield of energy as volatile compounds have been removed.

5. Coal has 0.4 times greater density as Coke has.

5. Coke typically has a specific gravity between 1.85 and 1.9. It is highly porous, and a mass of coke has 40% greater volume than the equivalent mass of coal.

6. Low quality coals, like Bituminous Coal contain smoke-producing constituents. The presence of these contents makes them unsuitable for domestic stoves and the furnaces launched near living areas.Bituminous Coal results in a large amount of smoke.But Coke may Burn without smoke.

6. Since the smoke-producing constituents are driven off during the coking of the coal, coke forms a desirable fuel for stoves and furnaces in which conditions are not suitable for the complete burning of bituminous coal itself. Coke may be burned with little or no smoke under combustion conditions which would result in a large amount of smoke if

bituminous coal were the fuel.

7. Coal can not be used directly as a reducing agent in smelting iron ore in a blast furnace, as the volatile compounds present in coal will cause to form foam and more slag.

7. Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace.

8. Byproducts of Coking (this conversion of coal to coke) include coal tar, ammonia, light oils, and "coal-gas".9. Bituminous coal must meet a set of criteria for use as coking coal, determined by particular coal assay techniques. These include moisture content, ash content, sulfur content, volatile content, tar, and plasticity.