Coke (fuel)

Coke is a solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. The volatile constituents of the coal, including water, coal-gas and coal-tar, are driven off by baking in an airless oven at temperatures as high as 1,000 degrees Celsius so that the fixed carbon and residual ash are fused together. Most coke in modern facilities is produced in "by-product" coke ovens, such as in the photograph on the right, and the resultant coke is used as the main fuel in iron making blast furnaces. Today, the hydrocarbons are considered the by-products of modern coke-making facilities (though they are usually captured and used to produce valuable products). Non-byproduct coke oven facilities, such as in the lower photograph, burn hydrocarbon off-gases on site to provide the heat needed to drive the carbonization process.