| 摘要 |
<p>Free fatty and resin acids are removed from an aqueous solution of soap such as soapstock, by adding an acid substance, such as hydrochloric or sulphuric acid or sodium bisulphate, with gentle stirring, to a prepared dilute solution of soap, to split the soap, and then subjecting the acidified solution to centrifugal separation so that the free acids and the acidified water are <PICT:0787715/III/1> discharged separately. The degree of dilution of the soap solution is such that, when the amount of acidic substance required for splitting is added, there is instantly formed only an emulsion of the free acids of a low-viscosity oil-in-water type. In the preparation of the soap solution, acid water in an amount insufficient to split the soap is preferably used. As shown, soapstock from tank 1 passes by line 4 to heater 5, where it is heated to 90-95 DEG C. before passing to mixer 7, where it is mixed with water introduced through line 8. From mixer 7 the soapstock passes to mixer 11, which is also supplied with concentrated acid through line 13 in an amount sufficient to split the soapstock. The resulting oil-in-water emulsion passes through line 15 to centrifugal separator 16, where the free acids are run off through 17, acid water is discharged through line 18 and funnel 27 to tank 30, and any unseparated emulsion is passed by line 19 to tank 20. This unseparated emulsion in tank 20, and the acid water in tank 30, are then introduced through line 8 to dilute the soapstock entering the process. Excess acid water in tank 30 is run off to waste through 29. Devices 9, 12 and 14 control the rate of flow of the various mixtures, the device 14 being actuated by pH meter 24 which has its glass electrode 23 immersed in tank 20. The flow of concentrated acid to mixer 11 is thereby controlled so that the pH of the unseparated emulsion leaving the separator 16 is maintained constant. The soapstock, which may have an initial fatty acid content of about 25 per cent, is usually diluted before splitting to a fatty acid content below about 10 per cent. Specification 719,472 is referred to.</p> |
