Crude Oil and Fractional Distilation

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Definition of Crude Oil

Crude oil is the untouched oil as it comes out of the ground. In order to make it useful for a wide range of purposes, it undergoes fractional distillation where the different lengths of alkanes are separated.

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Fractional Distillation

At different levels are bubble caps. The crude oil is heated and the longer chain of alkanes that have a high boiling point will rise out of the bubble cap, but when it reaches its fraction level higher up where it's cooler, the vapour condenses and runs out of the distiller.

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The groups of oil that are removed at different levels that have similar boiling points are called; fractions.

Fraction Uses
Gases A mixture of small hydrocarbons (ethane, propane etc.), liquified as LPG (liquified petroleum gas). This is a chemical feedstock (see below).
Petrol Used as fuel for cars.
Kerosene A fuel for jet engines and oil powered domestic heating. This fraction is used in cracking.
Diesel To power combustion engines in cars and ships.
Lubricating Oil Waxes, greases (like Vaseline) and polishes. Mostly used in cracking.
Bitumen Semi solid tar substance left over from distillation. Used for road surfaces and waterproofing roofs.

Chemical feedstocks are fractions used to produce various chemicals. Naptha is the chief feedstock and used in paints, cosmetics, drugs, glues and pesticides. This is why oil is so important to us today. Oil isn't just used in cars - and the rapid depletion (loss) of oil reserves is a critical issue.

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Article Info

Categories : Applied

Recent edits by: Jamie (ScienceAid Editor)

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