Technology Performances and Pilot Plant Design of Membrane Bioreactor for Efficient Bioethanol Production

Five runs of bench test for bioethanol production in membrane bioreactor with pervaporation or membrane distillation have been carried out for the evaluation of technology performances. Compared with the traditional batch mode, the equipment utilization efficiency can be increased to 1.5-2.0 times, the cell utilization efficiency can be improved 2-10 times and the amount of waste water can be reduced by 70%-85% in membrane bioreactor. The respiration heat released by the microbial cell during fermentation can be fully utilized for membrane separation to compensate 30%-60% of the energy required by pervaporation. Furthermore, the latent heat for condensing permeate vapor can be recovered by mechanical vapor compression (MVC) to save 50% energy consumption. In terms of the pilot plant, the power required is lower than 12 kW and the coproduction of single cell protein being 15 ton/a and ethanol being 300 ton/a can be expected