The core refining process is simple distillation
Because crude oil is made up of a mixture of hydrocarbons, this first and basic
refining process is aimed at separating the crude oil into its "fractions," the
broad categories of its component hydrocarbons. Crude oil is heated and
put into a still -- a distillation column -- and different products boil off and
can be recovered at different temperatures. The lighter products -- liquid
petroleum gases (LPG), naphtha, and so-called "straight run" gasoline -- are
recovered at the lowest temperatures. Middle distillates -- jet fuel,
kerosene, distillates (such as home heating oil and diesel fuel) -- come next.
Finally, the heaviest products (residuum or residual fuel oil) are recovered,
sometimes at temperatures over 1000 degrees F. The simplest
refineries stop at this point. Most in the