An Integrated Membrane-based Process Train for Reducing Costs of Ethanol Production

Production of ethanol derived from starch crops and biomass is forecast to grow considerably in the next decade. There exist opportunities for significant reductions in ethanol production costs and associated energy usage via employment of innovative process operations. Many of these processes involve membranes, which provide cost savings due primarily to reduced energy consumption. Recently, new hydrophobic pervaporation (PV) membranes have been developed by the proposing organization that (when scaled up to large sizes) will allow for displacement of distillation as the means for extracting and concentrating ethanol from the fermentation liquid. However, optimal deployment of these new PV membranes requires additional modifications in the ethanol process train. The overall subject of this SBIR proposal is development of an integrated process for more cost-effective production of ethanol from starchy crops. This process features microfiltration (MF) as one pre-treatment operation prior to the PV membranes. In Phase II, experimental work will focus on development of PV membrane cleaning procedures and of a second pre-treatment process that will scavenge membrane foulants from feed streams and thereby allow the PV membranes to operate at high efficiency for extended periods of time. The overall Phase II goal is to demonstrate economically attractive operation of an ethanol-extracting hydrophobic PV membrane for a period of at least 500 hours.