Hydration degumming is the use of phospholipids and other insoluble impurities hydrophilic gum, a predetermined amount of hot water or dilute alkali, salt, and phosphoric acid electrolyte aqueous solution are added under stirring in the hot crude oil, so that one of the water absorption gel aggregated insoluble impurities , then separated. This process uses the warm water of hydration process type, a small oil refinery in warm water commonly used method. Further, by adding a certain amount of hydrated phosphoric acid, after the reaction, the oil in the non-hydratable phosphatide, converted to chlorine factory hydratable phosphatide. Such phospholipid content is greatly reduced, can achieve better results unglued.

crude oil both contain a certain amount of free fatty acids, through refining, and crude oil may be in the majority of the big free fatty acids, fatty acid sodium salt does not dissolve generated in oil, become flocculation substance and sedimentation. Sodium hydroxide and sodium soaps of fatty acids and generated, fast response, and the resulting sodium soap surfactant adsorption and absorption capabilities are strong, can be a considerable amount of impurities, such as proteins, pigments, phospholipids and substances with hydroxyl also into the sediment, suspended solids and even fluff soap group may also be carried down, alkali refining most significant advantage is that having deacidification, degumming, off solid impurities, the combined effects of decoloration.

In addition to its oil pigment prolapse, but also serve to reduce the phospholipid content, peroxide value, the amount of soap and the role of the metal ion content containing oil to improve the color, flavor and enhance oxidative stability. The most commonly used method is activated clay adsorption decolorization, i.e.