Bioethanol Production

As stated in Melody Voith's article "Dow Plans Algae Biofuels Pilot," "fuel-quality ethanol must be distilled from the bioreactor condensate" (C&EN, July 6, page 10). One of the major hurdles facing bioethanol production is the energy-intensive distillation of ethanol from the fermentation mixture. However, ethanol boils at a lower temperature than water; distillation would not require as much heat as water.

Many manufacturing facilities, such as power plants, paper mills, and others have excess low-pressure steam that could be used to distill bioethanol. The availability of this heat resource suggests that ethanol fermentation facilities might be located more profitably near manufacturing facilities rather than close to agricultural sites.

Robert F. Cassidy Jr.
Stone Ridge, N.Y.