GB816792A - Improvements in or relating to processes for extracting and refining glyceride oils and fats - Google Patents

Abstract

<PICT:0816792/III/1> <PICT:0816792/III/2> <PICT:0816792/III/3> A combined extracting and refining process for glyceride fats and oils, particularly cottonseed oil, which is suitable for batch or continuous operation, comprises converting the oil-soluble impurities contained in the source material to water-soluble impurities by treating the source material in the presence of any included moisture with a refining reagent such as urea, sodium carbonate, sodium bicarbonate, or sodium phosphates, or with small quantities of sodium hydroxide, all preferably in the solid state, as a result of which the impurities are deposited on the source material, and thereafter extracting the fat by passing a selective solvent for the fat, suitably n-hexane, through the mixture while the included moisture is present. As shown, a preferred continuous embodiment comprises (Fig. 1) a screw conveyer 10 which supplies source material to a five-ring cooker 12, whence the material passes to salt feeder 28, where the material is mixed with the refining reagent fed in from hopper 29. The mixture then passes to press 16, where much of the oil is extracted by pressure and passes by line 17 to head tank 18 (Fig. 2). The source material from press 16 passes to flaking rolls 20, on which it is comminuted, and then to the top of extracting column 23, up which is flowed an extracting solvent supplied from tank 25. The resulting miscella passes through filter 38 to head tank 39 (Fig. 2), while the extracted residue from the bottom of the extracting column is removed by conveyer 32 to drier 34. The resulting meal is suitable as a cattle or poultry feed. The oil in head tank 18 (Fig. 2) and the miscella in tank 39 then pass through a T-duct 52, which interconnects rotometers 43 and 51, to proportionometer 41, where the oil or miscella is mixed with caustic soda solution supplied from tank 54. The mixture then passes to homogenizer 60, where the mixture is homogenized for 15-90 seconds with recycling under high pressure (usually more than 300 p.s.i.). The mixture passes through heat-exchanger 70 to soap centrifuge 74 (Fig. 3), where soapstock is removed and passed back into line 33 (Fig. 1) to be dried with the meal. The oil or miscella which leaves the centrifuge is washed in water-wash mixer 78 and separated from wash water in centrifuge 79, the water passing to decanter tank 81, where solvent may be separated and re-used. Pump 84 passes miscella successively to preheater 86, evaporator 87, flash chamber 88, and stripper 89, where solvent is removed and condensed by condensers 90, 91. The oil is finally passed either directly to storage or first to vacuum drier 96 fitted with condenser 97.