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--Anasdon (talk) 19:08, 16 January 2014 (UTC)FRACTIONAL DISTILLATION (THE SIX FRACTION)

'''The six fraction that are separated from crude oil are gases, petrol, Kerosene, diesel oil, fuel oil and bitumen. Gases are used for bottled gases, petrol for fuel for cars, kerosene is used in aircraft fuels, diesel oil is used for fuel for cars, lorries and buses. Fuel oil is used for ships and power station and bitumen is used for making roads and water proof roofs. When a hydrocarbon is burned in a limited supply of air, toxic gas is formed that is called Naphtha.

Fractional distillation differs from distillation only in that it separates a mixture into a number of different parts, called fractions. A tall column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with low boiling points condense at the top. Like distillation, fractional distillation works because the different substances in the mixture have different boiling points.

Fractional distillation of crude oil

Because they have different boiling points, the substances in crude oil can be separated using fractional distillation. The crude oil is evaporated and its vapours allowed to condense at different temperatures in the fractionating column. Each fraction contains hydrocarbon molecules with a similar number of carbon atoms.

the main fractions include refinery gases, gasoline (petrol), naphtha, kerosene, diesel oil, fuel oil, and a residue that contains bitumen. These fractions are mainly used as fuels, although they do have other uses too. Hydrocarbons with small molecules make better fuels than hydrocarbons with large molecules because they are volatile, flow easily and are easily ignited.

Fuels burn when they react with oxygen in the air. The hydrogen in hydrocarbons is oxidised to water (remember that water, H2O, is an oxide of hydrogen). If there is plenty of air, we get complete combustion and the carbon in hydrocarbons is oxidised to carbon dioxide: hydrocarbon + oxygen   →    water + carbon dioxide Incomplete combustion If there is insufficient air for complete combustion, we get incomplete combustion instead. The hydrogen is still oxidised to water, but instead of carbon dioxide we get carbon monoxide. Particles of carbon, seen as soot or smoke, are also released.

The combustion of a fuel may release several gases into the atmosphere, including: water vapour carbon dioxide carbon monoxide particles sulphur dioxide These products may be harmful to the environment.'''

BY M.ANAS.BIN.IKHLAQUE