How is crude oil separated at an oil refinary?

Answer 1

Crude Oil is separated at a oil refinery by fractional distilation chamber. The oil is boiled and vapourised, and moves along a tube into the bottom of the chamber, which is hot at the bottom (around 350degrees c) and cool at the top - around 40. The mixture of hydrocarbons, such as ethane and octane, rise up the column to the temperature at which they condense and become liquids - tubes leading off each section, or fraction, collect these substances. At the very top of the chamber, the petrolum gases, which include methane (which has a very low boiling point) and propane, have too-low boiling points to condense into liquids, so those gases float up through the tube at the top, and are collected. The substances collected in each fraction have all got different uses - e.g. Petrol is used for fuel for cars, and bitumen, the residue at the bottom of the chamber, is used for road surfacing. The substances collected higher in the fractionating column are less viscous and ignite more easily, and vice versa.