Fractional Distillation, Crude Oils and Alkanes

Crude oils

• The term 'crude oil' refers to a natural oil found in small reserves deep underground. It is a non-renewable fossil fuel.
• Crude oils are mixtures of various different types of hydrocarbons (compounds made of hydrogen and carbon), and using fractional distillation, they can be separated out into their respective types, or fractions, because each fraction has a different use.
• while fuels produced from crude oils are effective, they are in short supply, so new methods of power are currently being researched.

Fractional Distillation

• Fractional distillation is the process of separating the different compounds in crude oils.
• The crude oil is heated to 350 degrees celsius, and is fed into the bottom of a fractionating tower.
• as the crude oil vapourises, it rises up the column.
• There are sections in the column that are at different temperatures, getting cooler towards the top. The fractions have different boiling points, so they condense in the different sections.
• At the bottom is bitumen, used to make tar, with the longest molecular chains and highest boiling point (above 350 degrees celsius), with the shortest chain molecules with the lowest boiling points at the top.