How do you separate petrol from crude oil?
Petrol is obtained from crude oil by fractional distillation and subsequent mixing of some of the fractions to obtain the desired properties. There are seasonal differences in petrol to facilitate vehicle operation under different climactic conditions. Some of the fractions for the petrol may be obtained by “cracking” higher molecular weight fractions to lower molecular weights. Some impurities, like sulfur, and some unsaturation of the fraction may be removed by treatment with hydrogen which replaces the impurity on the hydrocarbon molecule or adds hydrogen to the molecule to make it more stable. Some of the fractions may be treated to rearrange some of the molecules to make a more desireable product. It is a complex process that is highly dependant on the crude source, desired products, time of year, and the configuration of the refinery. From the same crude may come: fractions for making plastics, rubber, heating oil, diesel and gasoline fuels, lpg fuel, lubricants, solvents, petrol
