Saturday, March 14, 2009

Green gasoline: oxymoron or the future?

Gasoline is everyone's idea of the anti-biofuel—the stuff we're trying to get away from. Is it even conceivable to think of gas as green?

Well, sure, if it doesn't come from oil or coal, and particularly if it comes from a renewable source.

(Image: University of Wisconsin student Edward Kunkes in the lab used to convert sugars into liquid fuels. Credit: Jim Dumesic, University of Wisconsin.)

What if you make it out of sugar cane? Better yet, what if you can make it out of non-edible sugars in agricultural waste and non-food plants?

Everybody knows you can efficiently make alcohol out of sugar, and create either rum or a fuel that can run an engine. Not everybody likes using ethanol fuel, and it does have its unique set of issues. Now new research has developed a way to make gasoline out of sugars.

Two independent groups using different approaches came up with the discovery.

“Sugars and carbohydrates can be processed like petroleum into the full suite of products that drive the fuel, pharmaceutical and chemical industries,” says the National Science Foundation press release on the work.

The independent teams, both working in Madison, Wisconsin, were Randy Cortright and associates at Virent Energy Systems, and James Dumesic at the University of Wisconsin. Madison isn't that big a city, and these guys obviously know each other. Cortright used to be a student of Dumesic.

The techniques have been discussed since as early as 2006. They call the system aqueous phase reforming.

“In passing a watery slurry of plant-derived sugar and carbohydrates over a series of catalysts—materials that speed up reactions without sacrificing themselves in the process—carbon-rich organic molecules split apart into component elements that recombine to form many of the chemicals that are extracted from non-renewable petroleum,” the release says.

The process yields an oil that can readily be converted into gasoline. Being able to buy gasoline made from sugars from this process is still a few years off, but the scientific teams are sure they can get there.

Said Cortright: "Our scientists now have years of expertise with our BioForming process and are rapidly moving the technology to commercial scale. We are quickly working to put our renewable, green gasoline and other hydrocarbon biofuels in fuel tanks all over the world."

But isn't gasoline a fuel source of the past?

"Even when solar and wind, in addition to clean coal and nuclear, become highly developed, and cars become electric or plug-in hybrid, we will still need high energy-density gasoline, diesel and jet fuel for planes, trains, trucks, and boats," said John Regalbuto, director of the Catalysis and Biocatalysis Program at the National Science Foundation.

One of the interesting things about gasoline, Virent says, is that it spontaneously separates from water. Ethanol, by contrast, must be distilled to separate it from water, and that's an energy-intensive process.

Green gasoline is not by any means the only big advance going on in fuel science. Here's just one other.

Researchers at Penn State have found they can produce hydrogen through electrolysis using cheap stainless steel cathodes instead of ones made of expensive platinum. They get similar yields, and although it takes a little more steel than platinum, it's so much cheaper that it saves bundles.

"Stainless steel brush cathodes can produce hydrogen at rates and efficiencies similar to those we have achieved with platinum-catalyzed carbon cloth," says Bruce E. Logan, Kappe professor of environmental engineering.

©2009 Jan TenBruggencate

1 comment:

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