Fractional Distillation occurs when a mixed liquid is heated up until each component or fraction boils and evaporates

fractions have different boiling points, when the boiling point for a certain compound is reached the vapor being evaporated off lands in a different container where there will be a more pure sample of that compound. Just like distillation, fractional distillation works because the different compounds in the mixture have different boiling points. Fractional Distillation is used very commonly in petroleum refineries, petrochemical and chemical plants and natural gas processing plants.  In petroleum refineries fractional distillation is used to separate the different fractions found in crude oil. The process of how crude oil separates through fractional distillation is as follows, first the crude oil is inserted through a furnace where it is heated, and then the crude oil moves from the furnace to the distillation tower. At the bottom of the distillation tower the temperature will be the highest, which is at around 400°C, and at the top of the distillation tower the temperature will be the lowest, which is around 20°C.  Fractions of the crude oil that does not boil sinks to the bottom of the tank and goes through a pipe. The fraction of the crude oil that does not boil is known as bitumen, which is used for roads. The other compounds boil and rise up the distillation tower; these are the fractions with low boiling temperature. This happens because the fractions that have low temperature points have small molecules, which means they are very volatile, easily move around, have low boiling points and easily ignite. The fractions at the bottom have large molecules and are the complete opposite, of the small molecule compounds. So as the small molecule compounds rise up the tower, it starts to get colder, and each compound boils at a certain point throughout the tower. When the compound boils, it exits the tower through the closest pipe next to it. The different fractions found in crude oil (ordered from highest boiling point to lowest boiling point) are bitumen, fuel oil, diesel oil, kerosene, naphtha, petrol and refinery gases.         Fractional Distillation is when different compounds in a mixture separate from each other by heating it up until   Resources: http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/rocks/fuelsrev3.shtml http://en.wikipedia.org/wiki/Fractional_distillation#Industrial_distillation http://jonathoncampbell.hubpages.com/hub/Crude-Oil-and-Separating-CrudeOil http://answers.ask.com/Science/Chemistry/how_does_fractional_distillation_work  By: Abdul Rahim Altiti 10AA