What coke is and how it is made
Coke is produced by the pyrolysis of bituminous coal at high temperatures – exceeding 1,000 °C – in the absence of air. Coke is produced from hard coal, preferably with a low sulphur content and other favourable parameters. The coking process yields tar, ammonia, raw benzol, coal gas and hydrogen sulphide.
Coking process
- Preparation and handling of coal
- Charge preparation
- High-temperature carbonisation (coal charging, coking, removal and quenching of coke)
- Processing and separation of coke
- Cooling and cleaning of raw coal gas and separation of chemical byproducts
Various uses of coke
Coke is used as a fuel and a reducing agent, for example in blast furnaces when producing iron or in cupola furnaces when producing cast iron or insulating materials. Coke can also be used as a fuel for heating or as a raw material in some chemical processes.
Coke made from coal is grey in colour, hard and porous.
The heating value of coke is 29.6 MJ/kg.
Coke can also be created by a natural process, when coal strata are exposed to hot magma.
Coke can be produced when processing crude oil; however, the composition makes it unsuitable for iron production.
Coke in space
The porosity of coke makes it an exceptionally good thermal insulation material. It is and has been used in the US space programme as one of the components of the spacecraft thermal protection system. The Apollo space programme thus carried this material to the Moon orbit in the thermal shield of the command and service space vehicle. It is planned that coke will be used in the Orion spacecraft designed to return people to the Moon and enable the conquest of Mars.