GB550705A - Improvements in or relating to the treatment of oil or fat-containing material for the recovery of oil or fat therefrom - Google Patents

Abstract

550,705. Extracting fats and oils. SILBERSTEIN, V., KERNOT, J. C., and ATTARI, H. July, 18, 1941, No. 9102. [Class 91] In the recovery of oil or fat from animal and vegetable material including waste, and also from used filtering earths and carbons, by treating the material in a vessel in the presence of an aqueous medium of lowered surface tension and at a temperature not substantially exceeding 100‹C., the oil or fat rising to the surface of the liquid and being thereupon removed, the remaining liquid is drained off and the residual material is removed from the vessel and subjected to treatment in another apparatus, such as a centrifuge, so as to expel any aqueous medium retained therein. The materials for adding to the water to lower the surface tension are similar to those described in Specification 543,424. The treating vessel 1 of a suitable plant is provided with hinged, perforated semi-circular elements 12, 13 and 16, 17 to form spaced filtering plates for containing the raw material therebetween, a number of rotatably mounted perforated tubes 21 and a similar paddle 22 for admission of steam to the contents of the vessel all arranged beneath the lower filtering plate, and a steam jacket around its lower part. The vessel is filled with the aqueous medium to just below an overflow pipe 3. The material is preferably subjected to steam treatment, superheated or not, prior to the introduction of the aqueous medium to the vessel, so as to break the fat-containing cells. In the subsequent treatment with the hot liquid the heating thereof may be supplemented by passing steam through the tube and paddle. After the solution has been boiled for a period, it is allowed to remain quiescent and thereafter by addition of further solution the supernatant fat or oil is caused to overflow into a jacketed collecting vat 8. The remaining liquid is drained into a settling tank 42, and the residual material then discharged through a door 44 for treatment according to the second stage of the process, such as in a steam jacketed centrifuge 34, prior to optional treatment in a dryer 46. The fat or oil in vat 8 is then processed by passing it through a separator 48, deodorizer 52 and filter press 54. The dried residue may be used as animal food or as a fertilizer.