Organic+-+Thermal+cracking.

=Introduction= Oil refinery in California. Photo: CA Energy Commission Cracking is a [|petroleum refining] process in which heavy-molecular weight hydrocarbons are broken up into light hydrocarbon molecules by the application of [|heat] and pressure, with or without the use of catalysts, to derive a variety of fuel products. Cracking is one of the principal ways in which crude oil is converted into useful fuels such as motor gasoline, jet fuel, and home heatng oil. [| http://www.eoearth.org/article/Cracking]