Fractional distillation of Crude Oil
Hydrocarbons are important molecules in crude oil. They contain carbon and hydrogen atoms only.
The length of the hydrocarbon determines there state of the molecules. If the hydrocarbon chains are short this means that the hydrocarbons in the short chain are runny, easy to ignite and have low boiling point. They are also more useful that longer chains and can be used for fuels. On the other hand the molecules the longer hydrocarbon chains are more viscous, harder to ignite and have higher boiling points.
However before hydrocarbons can become useful they must first be separated into groups with similar carbon atoms, they are called fractions.
Crude Oil is separated through fractional distillation. This is how the process works : -
1) Crude oil is first heated until it evaporates.
In a fractionating column it is much hotter at the top of the column and cooler at the bottom.
2) This results in the short hydrocarbon molecules reaching the top of the column before they condense so they are collected. Longer hydrocarbon molecules condense at higher temperatures are are collected at different points nearer the bottom of the column.
Although the longer hydrocarbon molecules become separated they after the fractional distillation process however they are still not useful, to be used as fuels and other products. However the hydrocarbon molecules can be broken down into smaller more useful valuable molecules by a process called cracking.