Application of Polymer Membranes to Alcohol Concentration in Fermentation of Biomass

Abstract

It is required that aqueous alcohol solutions produced by a biomass fermentation technique are concentrated and separated by some methods to use a concentrated alcohol as fuels. There are many techniques for concentration and separation of aqueous alcohol solutions. Membrane separation techniques are worth noticing to be able to concentrate and separate liquid and gas mixtures in low energy consumption. In particular, pervaporation which is one of them is a very useful technique for the concentration of organic liquid mixtures¹. When an aqueous ethanol solution produced by the biomass fermentation is required to be concentrated by the membrane separation techniques, two type membranes will be able to be applied. Namely, if an aqueous ethanol solution is distillated and then an azeotropic mixture is given, water-permselective membranes are used to dehydrate water from the azeotropic mixture. On the other hand, if an aqueous ethanol solution is concentrated directly, ethanol-permselective membranes can be applied to concentrate ethanol in an aqueous ethanol solution.