GB466596A - Continuous countercurrent hydrolysis of fat - Google Patents

Abstract

<PICT:0466596/III/1> In a continuous splitting process, fat and water separately heated to 300--600 DEG F. and under pressure sufficient to maintain the water liquid are passed in countercurrent through a vertical chamber, the water being in an excess at least equal to the weight of glycerine to be liberated and the time of contact sufficient to cause at least 95 per cent splitting. The pressure may be 125--1600 lb. the time of contact at least 30 min., and the proportion of water suitably such as to produce a "sweet water" containing 20--50 per cent of glycerine. Any splitting catalyst may be used, preferably mixed with the fat; oxides and soaps of zinc, calcium and magnesium are specified. In one example, 3500 lb. of water and 7500 lb. of tallow respectively per hour are passed through deaerators 1, 2, meters 3, 4, pumps 5, 6, heaters 7, 8 connected to a boiler 9, and over thermometers 24, 25 to pipes 15, 14 by which they are distributed into an autoclave 13 maintained at 470 DEG F. and under 600 lb. pressure. Zinc soap, equivalent to 0,25 per cent of zinc oxide relative to fat, is passed from a vessel 10 through a pump 12 to the fat issuing from the heater 8. The fat takes 1 hr. to pass through the autoclave, and is 99 per cent split. The fatty acids pass through an automatic pressure control valve 23 to a tank 16 where they are flasked to atmospheric pressure, the water vapour discharging through a pipe 18 and the acids through a pipe 17; the escaping steam blankets and so protects the fatty acid from air. The "sweet water" containing 24 per cent of glycerine passes through a discharge rate and pressure-controlling valve 22, and is flasked in a chamber 19 to atmospheric pressure, steam passing through a pipe 21, and the "sweet water" now of 32 per cent glycerine content, discharging through a pipe 20. In the spaces in the autoclave above the pipe 15 and below the pipe 14 are water settled out from fatty acid, and fat from glycerine water respectively, the interface between the fat and water preferably being at about the level of the pipe 14 as shown by the gauge 26. The efficiency of the process is attributed to the solution of water in the fat under the conditions. Curves showing the percentages of liquid water dissolved by fatty acids of tallow and coconut oil at different temperatures are given; means by which such a curve for any fatty acid is obtained are described; and a formula is supplied to predetermine the proportion of water to be used to obtain "sweet water" of a specified glycerine content. In the above example about 11 per cent of water is stated to be dissolved in the fat.