Recovery of oils from filter cake of decolourising earth - includes mixing with volatile solvent and decanting mixt. over water

摘要

The filter cake is mixed with a highly volatile solvent. and the earth is sepd. from the mixt. which is then distilled to recover the oil. The mixt. of oil, solvent and earth is fed continuously into a decanting vessel to form a layer of suspension on top of the surface of water lying in the vessel. Earth settles progressively to the bottom of the vessel, residual oil/solvent on the earth being washed off by the water. The oil/solvent mixt. rises through the suspension layer to a top overflow. The depth of settled earth and the depth of water are pref. both controlled within predetermined limits. The speed at which the mixt. riset through the suspension layer is pref. related to the density and grain size of the earth, and to the density and viscosity of the mixt. The mixt. formine the suspension is pref. introduced into the upper third of the decanting vessel. The solvent is pref. hexane and the process temp. held between 40 degrees and 50 degrees C. The proportion of solvent used pref process a mixt. with an oil content of 10-15% used in refinning oils. fats etc.