Fractional distillation: To separate two or more liquids that are miscible with one another
Industrial process of fractional distillation:
The process of fractional distillation to separate crude oil in a fractionating column
Fractional distillation is carried out in a fractionating column.
- In the fractionating column, it is hot at the bottom and cool at the top.
- Crude oil will enter the fractionating column and will be heated so vapours will rise and evaporate.
- Vapours of hydrocarbons with very high boiling points will immediately turn into liquid and are tapped off at the bottom of the column.
- Vapours of hydrocarbons with low boiling points will rise up the column and condense at the top to be tapped off.
- The different fractions will condense at different heights according to their boiling points and will be tapped off as liquids. All the fraction are mixtures of different kinds of hydrocarbon.
To conclude the smaller hydrocarbons are collected at the top of the fractionating column as gases. The bigger hydrocarbons are collected at the lower sections of the fractionating column.