Degumming is the first operation in refining. The Impac® Degumming process consists of a mere hydration of the crude oil. Certain impurities like phospholipids, gums and proteins are soluble in oil in their anhydrous form, but insoluble once they are hydrated. This is how the hydratable phospholipids are removed from the oil. Part of the constituents however remain in the oil, and an acid treatment is needed to remove them.
Water degumming is more generally carried out in the extraction plant rather than in the refinery, lest foots should conglomerate in the crude oil intermediate tanks.
The aqueous phase obtained after degumming separation is recirculated into the meal stream of the toaster. Should lecithin be of significant commercial value, it can be dried separately.