Main Steps of Edible Oil Refining
1. Crude Oil Degumming: In this step gums in crude oil are removed by hydration with the help of phosphoric acid.
2. Neutralization: In this step free fatty acids are neutralized by using sodium hydroxide and convert them into soap. Additional impurities are also removed by adsorption on soap.
3. Bleaching: During bleaching, unwanted pigments are adsorbed physically and oil will become much clearer.
4. Deodorization: Deodorization is used to remove unacceptable odors by steam distillation, the odoriferous compound are stripped off with the help of live injected steam into heated oil under high vacuum pressure.
5. Dewaxing (necessary for cold areas)
Some kinds of oil like sunflower, maize germ or corn oil have waxes inside, if these impurities are not removed, the oil will freeze easily under low temperature, thus effecting oil quality and appearance. so this process is necessary in extremely cold areas.
Edible Oil Refining Equipment
1. Decoloring tank: bleach pigments from oil.
2. Deodorizing tank: remove the un-favored smell from decolorized oil.
3. Oil furnace: provide enough heat for the refining sections which need high temperature of 280℃.
4. Vacuum pump: provide high pressure for bleaching, deodorization which can reach 755mmHg or more.
5. Air compressor: dry the bleached clay after bleaching.
6. Filter press: filter the clay into the bleached oil.
7. Steam generator: generate steam distillation.
