Bioethanol Production with Membranes

75027S The development of bio-based fuels can help reduce our nation's dependence on imported oil. This project will develop an integrated membrane pervaporation-dephlegmation-dehydration process to separate water from ethanol and produce 99.5% fuel-grade ethanol. In particular, high-flux, moderately-selective membranes will be developed for the dehydration step of the integrated process. The new membranes would lower capital and operating costs, increasing the competitiveness of biomass-to-ethanol process, compared to distillation and molecular sieve technologies. In Phase I, composite membranes were made, and their performance was evaluated in laboratory stamps and in bench-scale. Membrane permeances exceeded those for existing commercial pervaporation membranes by a factor of 4 to 5. An economic analysis of the total process showed that if the new membranes were formed into commercial-scale spiral-wound modules, the costs would be significantly less than current technology. In Phase II, a pilot unit, which uses a membrane-based pervaporation-dephlegmation-dehydration process, will be constructed, field tested, and evaluated. The field test will be used treat a slipstream at a corn-to-ethanol plant or a whey-lactose stream from cheese production. Commercial Applications and Other Benefits as described by the awardee: The pervaporation-dephlegmation-dehydration process being developed should allow a large number of small (50 ton-per-day) fermentable waste biomass streams to be economically converted to ethanol. Such streams are produced in cheese, wine, beer and sugar production. Distillation is too expensive to use for ethanol recovery at this small a scale. Nationwide, more than 200 new process plants could be installed. The process also could replace molecular sieve dehydration in large corn-to-ethanol plants.