SOLVENT RECOVERY AND PARTIAL DEACIDIFICATION OF VEGETABLE-OILS BY MEMBRANE TECHNOLOGY

A process is described using nanofiltration membranes for the partial de-solventizing and de-acidification of hexane-extracted vegetable oil s. The model miscella (containing 20% soybean oil with 2% free fatty a cids) was concentrated to 45%, oil at an average flux of 9 l/m(2)h at 2.76 MPa and 24 degrees C. The permeate from this stage was re-concent rated 9-fold at an average flux of 20 l/m(2)h. The net recovery of oil was more than 99%, with a simultaneous 40% reduction of FFA and over 50% reduction in the energy required for evaporation of hexane.