Crude Oil and Hydrocarbons

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Crude Oil and Hydrocarbons

Petroleum, also known as crude oil is formed from fossilized remains of marine plants and animals that settled on the sea floor millions of years ago. Petroleum consists of a complex mixture of hydrocarbons molecules including parrafins, aromatics, napthenes/ cycloalkanes, alkenes and alkynes. Hydrocarbons are molecules that contain hydrogen and carbon atoms that form various structures from straight chains to branching chains and rings. Hydrocarbons with low molecular weights, such as propane (C3H8) are in a gaseous form. Octane and kerosene are both liquids and have medium molecular weights, whilst the larger hydrocarbons are solids such as tar and bitumen.

Fractional Distillation

Oil drilling occurs both at land and at sea, and is then transported to an oil refinery. Fractional distillation is the process in which the different length hydrocarbon chains are separated by their boiling points, which are dependent on the length. These different length chains are called fractions. The shorter carbon chains evaporate more easily than the longer chains. In order to separate the different length chains in crude oil, the mixture is heated at very high temperatures in a distillation tower. The distillation tower becomes progressively cooler from the base to the top and as all the hydrocarbons begin in the gaseous stage they rise. As the vapours rise fractional condensation occurs at different sections of the tower (Roger, 2010).

Some products that come from crude oil include; petroleum gas, naphtha, petroleum, kerosene, lubricating oil, fuel oil and residuals such as asphalt and tar. Although all fractions of crude oil have uses, the greatest demand requires that over 50% of the crude oil be converted...

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