Crude benzene is one of many different by-products, resulting in the manufacturing coke in a coking plant. All these materials are produced by a pyrolysis process, the heating in the absence of air at high temperatures, of suitable grades of hard coal.

While the main product coke is needed particularly for the industrial production of pig irons in blast furnaces, further by-products like ammonium sulphate, sulphuric acid, tar and crude benzene are recovered from the coke oven gas.