Question

Explain the principle used to refine petroleum.

Answer 1

Petroleum is a mixture of various components. These components are separated from each other on the basis of difference in their boiling points. The components of petrol are termed as fractions and the technique used for their separation is called fractional distillation.
The process of separating the various components of petrol by fractional distillation is called refining.

The difference in the boiling points of the components of petrol is due to the number of carbon atoms present in them. More the number of carbon atoms, higher will be the boiling point.

During this process, the crude oil is heated to about 400^oC in a furnace. The vapours which are formed during this process are passed into a fractionating tower. The component with the highest boiling point will condense first and collect near the base of the tower.

More and more vapours will be produced with lower boiling points and will condense at different heights. These components are separated as different fractions which are finally collected.