Coke

Raw coke

Coke is a fuel with a high carbon content and few impurities, usually made from coal. It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulphur bituminous coal. Cokes made from coal are grey, hard, and porous. While coke can be formed naturally, the commonly used form is synthetic. The form known as petroleum coke, or pet coke, is derived from oil refinery coker units or other cracking processes.

Coke is used in preparation of producer gas which is a mixture of carbon monoxide (CO) and nitrogen (N₂). Producer gas is produced by passing air over red-hot coke. Coke is also used to manufacture water gas.