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Solid catalyst simplifies turning algae into biodiesel

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American



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As home biodiesel brewers know, it's a time-consuming and chemically intensive process to transform French fry grease into a fuel. And then there's the problem of burning something in your truck that could have fed people; canola oil can be used for food or fuel, for example.

That's why many biodiesel devotees—including DARPA, the Defense Department's research arm—have turned to plentiful algae: it grows like a weed and certain strains can be turned into buckets of oil. Plus, it's not a nutritional staple like soy or palm oil.

The question is: How do you convert algae oil into biodiesel efficiently?

United Environment & Energy, an engineering company in Horseheads, N.Y., believes it has the answer. By using a "mixed metal oxide" catalyst (a form of certain metals resistant to corrosion but reactive), chemical engineer Ben Wen and his colleagues at United have come up with a conversion process that is 40 percent cheaper than an industrial scale version of the traditional methanol and lye process (methanol costs about 65¢ per gallon while lye is about $4 per pound). That process must also be finished by purifying the biodiesel with water to wash out left over chemicals that then linger in the water.

This new process would make biodiesel that also doesn't require the purification step, because there is no liquid catalyst mixed into the resulting fuel, Wen says. He notes that his company has made around 10 gallons of algae biodiesel this way to date, though its main interest is not in manufacturing the fuel but in selling the technology to make it to other companies. He says there are already some takers—including one that has made at least 100 gallons of the fuel and certified it to ASTM standards, a legal requirement to be sold in the U.S.—but he declined to identify any of them.

Other refining or fuel companies, such as Illinois-headquartered UOP and San Diego-based Sapphire Energy, are also aiming at producing oil and fuel alternatives from algae but have struggled to get adequate supplies of it. Wen says his company has a "stable supplier" of algae oil that he also refused to identify for competitive reasons. He adds that said supplier was not U.S.-based as environmental regulations in this country hamper use of the toxic solvents necessary to extract oil from the algae. "Algae growth is not a big problem, people know how to grow it," he says. "The big barrier is extraction."

Image: Courtesy of United Environment & Energy