Membrane Process for Bioethanol Production

Bioethanol is an established domestic chemical/fuel product that is environmentally friendly and offers the possibility of strengthening the American farm economy, while simultaneously lowering dependence on foreign oil. However, the broad-based introduction of bioethanol is limited by the high cost of separating and recovering fuel-grade ethanol from the fermentation solution, particularly when bioethanol is produced from distributed biomass. This project will develop a more efficient ethanol production process, in which fermentation is combined with a membrane separation process, so that ethanol can be continuously extracted from the fermentor. In Phase I, a nanoporous membrane, capable of selectively removing ethanol from the fermentation solution, was developed, and the production of concentrated ethanol was demonstrated in bench-scale tests, using a single step process. The novel membrane exhibited an order-of-magnitude increase in ethanol/water separatation, compared to prior-art membranes. An initial economic analysis showed that the membrane separation process would significantly reduce ethanol production costs and process energy consumption, compared to traditional distillation. In Phase II, membrane performance will be optimized, a pilot scale membrane module will be constructed and tested, and a commercial-scale hollow-fiber membrane module will be developed. Commercial Applications and other Benefits as described by the awardee: The new membrane technology should reduce the cost of producing bioethanol, a renewable energy source and fossil fuel substitute, and provide an energy efficient process that integrates fermentation with ethanol separation. Increased bioethanol production would reduce U.S. dependence on foreign oil, enhance national security, and reduce atmospheric emissions