GB1090114A - Treatment of oils - Google Patents

Abstract

Free fatty acid in fatty oils (including molten fats) is neutralized with a liquid, oil-immiscible treating agent by a process in which the oil is continuously supplied to form a film on a moving carrier surface, each point on which follows a closed path, and said film is then carried without disruption or substantial movement relative to said surface through a body of the liquid treating agent, and is continuously removed from the surface. The treated oil after removal from the carrier surface may be fed to a pool of treated oil partly covering the body of treating liquid, the treated oil being continuously removed from pool. Two types of carrier surface are described, namely a rotating drum and a rotating disc, both of which rotate about horizontal axes and dip into a bath of treating liquid. Unrefined oil is fed to a descending surface of the carrier, in the case of the disc to both side thereof. Apparatuses embodying both types of carrier surface are described in detail. The process is particularly suitable for the alkali refining of glyceride oils, the treating agent being aqueous caustic soda, suitable of normality 0.1-0.8 N, which may contain minor amounts of soap or other melting agent, e.g. dodecyl benzene sulphonate, and an electrolyte, e.g. NaCl. When the unrefined glyceride oil has a high free fatty acid content the moving surface may be made lipophilic, e.g. by treatment with aluminium stearate. Unrefined oils treated in examples are palm kernel oil, coconut oil, groundnut oil, soya bean oil, rapeseed oil, and cottonseed oil.