How is petroleum refined into different products?

Petroleum is refined into different products through a process called fractional distillation in a petroleum refinery.

Fractional distillation is a process that separates a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point. The process of refining petroleum into different products begins with the raw material, crude oil, which is a mixture of hydrocarbons with different molecular weights.

In a petroleum refinery, the crude oil is heated to a high temperature, causing it to vaporise. This vapour is then fed into a distillation column, also known as a fractionating column. This column is filled with trays or plates, and as the vapour rises, it cools and condenses on these trays. The different fractions of the crude oil have different boiling points, so they condense at different levels in the column.

The lighter fractions, such as petrol and kerosene, have lower boiling points and condense at the top of the column. Heavier fractions, such as diesel and lubricating oil, have higher boiling points and condense lower down. The heaviest fractions, such as bitumen, do not vaporise at all and remain at the bottom of the column.

Each fraction is then collected separately and undergoes further processing to remove impurities and to create the final products. For example, the petrol fraction is treated to remove sulphur compounds, which can cause air pollution when the petrol is burned. The diesel fraction is treated to remove aromatic compounds, which can be harmful to human health.

In summary, the process of refining petroleum into different products involves heating the crude oil, separating it into fractions by their boiling points in a distillation column, and then treating each fraction to remove impurities.