Algae-To-Fuel: The Tough Part

Ethanol (Shutterstock)The New York Times (and its Green Inc. blog) are covering Dow Chemical and startup company Algenol Biofuels' newly announced plan to build a pilot plant for converting carbon dioxide into ethanol. (You'll hear more about this story in C&EN soon). As you might be able to guess from Algenol's name, the idea is to use specially-engineered algae to make the ethanol, which would be used as fuel or as a feedstock for plastics. Both of the stories are business stories, so I don't expect them to have a great deal of information about the science behind this announcement. But it's important to emphasize a potential stumbling block for this technology-getting the ethanol the algae makes into a usable form. The Times's online edition mentioned that concern briefly in their story, while Green Inc. doesn't mention it. From the Times story: Among the steps still being improved is the separation of the oxygen and water from the ethanol. The Georgia Institute of Technology will work on that process, as will Membrane Technology and Research, a company in Menlo Park, Calif. It takes plenty of energy to distill ethanol- I'm not clear on where Dow/Algenol are going to obtain the heat to do the distillation, and how that fits into the overall carbon dioxide balance for their process. Membrane Technology and Research, one of the partners mentioned in the Times article, is working on ways to save energy during the distillation step. That link provides a little more detail about their energy-saving process, which combines distillation and permeable membranes. I wish Dow, Algenol, and partners the best in getting U.S. Department of Energy grant they're after. We'll never know if this or any alternative fuel-making process is feasible on a practical scale unless someone ponies up for the tinkering and testing phase. Image: Shutterstock

Author: Carmen Drahl

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