Long-chain carbon refinery

Long-chain carbon refinery conversion of oils and fats to biodiesel and chemicals. 

Petroleum is by far the largest source of the vast number of products broadly known as petrochemicals. Raw petroleum is a mixture of hydrocarbons containing up to 40 carbon atoms per molecule. These large molecules are not useful in their natural form, but they are broken into smaller molecules in petroleum refineries (Fig. 21.13 also see Fig. 18.7). Catalytic cracking essentially cracks the long carbon chains into shorter molecules of 5 to 10 carbon atoms. Fractional distillation separates hydrocarbons into fractions that boil at different temperatures. Alkanes of up to 4 or 5 carbon atoms per molecule may be obtained in pure form by this method. The boiling points of larger alkanes are too close for their complete separation, so chemical methods must be used to obtain pure products. 

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