Crude Oil

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Crude Oil Crude oil is a complex mixture of hydrocarbon molecules formed over millions of years when the remains of microscopic sea creatures trapped in sediments were converted by heat and pressure into crude oil. The most abundant of these mixtures are the ones containing hydrogen and carbon only. These hydrocarbons can take on a number of different forms, i.e. alkanes, alkenes and alkynes. They vary in size and shape and viscosity. By manipulating these chains of hydrocarbons you can create any number of useful substances as they are very adaptable. However there are lots of compounds that also contain some of the following; oxygen, sulphur or nitrogen. The purer hydrocarbon compounds are the most required for these produce a higher temperature when they are burned which is the primary use for it as it generates an excess amount of energy when burned and therefore is a useful fuel. The other compounds with sulphur or nitrogen also have a high energy when burned but they have a negative side-effect as they make sulphur dioxide and nitrogen dioxide when burned and these compounds contribute towards acid rain. Crude oil has to be refined by fractional distillation to separate the short productive hydrocarbon chains from the longer, less useful ones before the compounds can be put to good use. Fractional distillation is a technique that relies on the difference in boiling points of the chains of hydrocarbons to separate them. It is so specific that it can separate the substances from each other even when there is only a small amount of difference between the boiling points of the substances. The crude oil is heat... ... middle of paper ... ...ne, which are used to manufacture chemicals. Or the residual from the distillation tower is heated 482°C, cooled with gas oil and rapidly burned in a distillation tower. This process reduces the viscosity of heavy weight oils and produces tar. The other method of cracking is called Catalytic Cracking and it uses a catalyst to speed up the cracking reaction. Catalysts include zeolite, aluminium hydrosilicate, and bauxite. The hydrocarbons (only from the oil fraction) are heated in the same way but the catalyst speeds up the reaction by lowering the boiling point of the substance and allowing high molecular mass alkanes to break into many low molecular mass alkanes and some alkenes. Because the bond breaking happens randomly, many different forms of the substances are made, i.e. cyclo or branched isomers.

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