Crude oil is a mixture of various hydrocarbons, is a viscous, dark brown liquid. Direct use of crude oil very wasteful, so will need to separate the components in crude oil, usually using distillation methods, that is, precise control of the temperature,making a specific component of the boiling point of flavor.
Vacuum distillation: atmospheric residue 8kPa distilled under the pressure of heavy distillate oil as lubrication oil, feedstock or cracking feedstock and residual vacuum residue in bottom. If the oil content of light oil or fuel oil market demand, crude oil distillation can also include preprocessing and atmospheric distillation of crude oil only two processes, commonly known as crude oil topping. Crude oil distillation fractions of some oil products raw materials; some secondary processing