Reduction of Distillation Usage in the Manufacture of Ethanol by Reactive Water Separation

Biomass-derived ethanol is now an integral and rapidly-growing part of the overall transportation fuel system in the U.S. However, distillation processes to remove water from crude fermentation ethanol consumes substantial energy, and adds to production costs. This energy usage contributes to the cost of manufacture of ethanol, requiring subsidies for general use in the transportation sector. This project will develop technology to reduce or substantially eliminate the reliance on distillation for water removal from biomass-derived ethanol. The approach involves the addition of a novel reactant to the crude ethanol, which will convert the water in the crude ethanol into a highly volatile product, by a reversible reaction over a solid catalyst. This volatile product will be readily removed from the remaining fuel-grade ethanol, at substantially reduced energy input. The volatile product is then regenerated off-line by reversing the reaction, producing water which separates by phase separation. Commercial Applications and other Benefits as described by the awardee: This reactive dehydration system should find immediate application to the production of fuel-grade ethanol from corn, and also could be applied to the production of ethanol from other biomass materials. In addition, because water must be removed in many industrial chemical process, such as the production of acetic acid, the technology should lead to opportunities for a major reduction in the energy requirements for dehydration in the production of chemical and fuels for the U.S. economy.