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 oils. The model miscella (containing 20% soybean oil with 2% free fatty acids) was concentrated to 45% oil at an average flux of 91/m2h at 2.76 MPa and 24°C. The permeate from this stage was re‐concentrated 9‐fold at an average flux of 201/m2h. 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.