This is a post on the NxRev Site.
Oil refineries break crude oil down into more usable material. It arrives via tanker or pipeline, and is then pumped into large storage tanks. The crude oil then begins to undergo distillation as it is vaporized when heated by the system.
Heavier oils then move down to a fluid catalytic cracking unit (FCCU). The FCCU uses heat, pressure, and a catalyst to convert heavy fractions into components that can be used in asphalt, bunker oil, diesel, gasoline, heating oil, jet fuel, marine gas oil, and propane.