General oil refinery layout

Crude oil is refined in three main steps, neutralization, bleaching and deodorizing, which remove fatty acids, colour, and off-flavours, respectively. Each of these processes involves heating the oil to a certain extent. The refining processes may be carried out in stages using batch plant, or by using equipment providing continuous operation.

Oil refinery layout

Oil refinery layout _ neutralization
The fatty acids are neutralized by mixing the oil with a solution of caustic soda. The caustic soda solution reacts with the fatty acids to produce soap which can be washed from the oil with water. The soap solution, known as soapstock, can be used for soap manufacture.
Oil refinery layout _ bleaching section
The oil is then bleached by adding a powdered clay known as 'Fuller's earth'. This operation removes coloured pigments and produces a light-coloured oil.
Oil refinery layout _ Deodorization
Deodorization is carried out by passing high pressure steam through the oil under vacuum to remove the taints and odours present in the oil at the beginning of the refining process, and those produced by the neutralizing and bleaching stages. A bland-tasting oil is finally obtained.