Carbon Chemistry: Fractional Distillation of Crude Oil

Crude oil is a complex mixture of hydrocarbons. These hydrocarbons have different boiling points, making fractional distillation a useful method for separating them.
Fractional distillation of crude oil is a physical process that separates the mixture into components (fractions) based on their boiling points.
Fractional distillation takes place in a fractionating column, a large vertical column heated from the bottom. This column is hotter at the bottom and gets cooler towards the top.
When crude oil is heated, it vaporises. The vapours rise through the column.
Hydrocarbons with higher boiling points (longer chain length) condense at the hot bottom levels, while hydrocarbons with lower boiling points (shorter chain length) continue to rise and condense further up where it’s cooler.
The ‘fractions’ collected at various levels in the column have varying properties and uses - the heavy fractions with high boiling points found at the bottom are often used as bitumen, lubricating oils, and fuels for ships and industrial heating. The intermediate fractions provide diesel oil, paraffin and heating oil. The lightest fractions at the top with low boiling points are largely used for petrol and other gases.
Carbon chemistry is a key aspect of this process as all the fractions are hydrocarbons, compounds containing only carbon and hydrogen.
Understanding the environmental impacts of the use of these fractions is crucial. The combustion of these hydrocarbons in vehicles and power plants contributes to air pollution, climate change, and other environmental issues.
Advances in science and technology are helping us find sustainable alternatives for these hydrocarbons, such as electric-powered vehicles and renewable energy sources, to reduce our dependence on crude oil.