GB539262A - Improvements in or relating to the refining of fatty oils - Google Patents

Abstract

539,262. Refining fatty oils. SHARPLES CORPORATION. Oct. 17, 1939, No. 28067. Convention date, Feb. 28. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 22, 1940.] Drawings to Specification. [Class 91] In the refining of fatty oils by treatment with alkali in at least sufficient amount to neutralize their fatty acid content, the oil is mixed with a small quantity of water prior to the alkaline treatment and after the treatment the finely dispersed water and soap stock resulting from the neutralization is promptly removed by centrifugation in a misco-separator. Oils specified are cottonseed, soya bean, palm, peanut, corn, cocoanut, babassu, palm kernel and tallow oils. The amount of water added is preferably between 0.5 and 5.0 per cent of the oil, whilst the time taken by the mixing of the alkaline re-agent, water and oil and the centrifugal separation is desirably less than 5 minutes and may be less than 1 minute. The mixing with water is preferably effected at a temperature of 115-160‹F. To remove any darkness in colour of the refined oil, the dispersion of alkaline re-agent and water in the oil may be subjected to an additional mixing step in a centrifugal emulsor just prior to the centrifugation, in which case a smaller amount of alkali may then be used. Generally, the alkaline re-agent, e.g. caustic soda, is of greater concentration than in standard refining practice and desirably exceeds 20‹ BaumÚ. To remove any soap stock remaining in the oil emerging from the misco-separator, it may be promptly washed with water, e.g. by mixing the oil with warm water and passing it through a further centrifugal separator. The water mixed with the oil prior to the alkaline treatment need not be in the pure state but may contain small quantities of alkalies, acids or salts, or even starch. In the examples, comparative figures are given for the amount and concentration of caustic soda used, the refining loss and the colour of the refined oil in the case of hydraulic cotton seed oil, expeller cotton seed oil, inedible tallow and cocoanut oil, all containing free fatty acid, when treated by the present process or by a known batch process or by the process of Specification 407,995. The Specification as open to inspection under Sect. 91 also describes the use of a more concentrated alkaline re-agent than customarily, and the washing of the refined oil with warm water, as features independent of the admixture with a small quantity of water just prior to the alkaline treatment. It also describes a process according to which the oil is degummed prior to the alkaline treatment by admixture with water and removal of the hydrated gums by centrifugal treatment. Figures are given which diagrammatically illustrate the various processes, together with examples which demonstrate the advantages of using higher concentrations of alkali and of a preliminary de-gumming operation in the refining of a number of oils, the separation of the soap stock being effected in each case by centrifugation while it is finely dispersed in the oil. This subject-matter does not appear in the Specification as accepted.