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Friday, May 06, 2005

Ethanol to Hydrogen

Reviewing some of my alumni junk mail, I discovered that one of the profs on my thesis committee has discovered something significant last year:
Dr. Lanny Schmidt, a University of Minnesota chemical engineer led a study on developing a cleaner-burning technology for fuel cells. Schmidt said the study proves the feasibility of using renewable hydrogen as an energy source.

According to the study, a cleaner-burning renewable fuel such as ethanol can produce hydrogen in a reactor to heat small homes and power cars more efficiently than the older fossil fuel technologies of oil and gas.
I can attest that this guy has really done a lot of fundamental research work (obligatory logrolling/disclaimer: he's cool and I passed my defense). Having stayed on the semiconductor side of things myself while he on basic catalysis, our groups used many of the same research equipment for studying material surface properties. In retrospect, I kind of dismissed studying catalytic reactions as a bit retro and old hat.
For the last 20 years Schmidt has had about 10 students working with him at any given time. The work is tough and not for the easily discouraged. Deluga recounts how prototypes of the reactor used to blow up inside a hood on a weekly basis, but Schmidt kept pressing him to keep working on the design. Despite such rigors, Schmidt's students call him "Lanny" and have great fun with each other. The lab's signature success is probably its work with novel catalysts that transform organic molecules into useful products. The hydrogen reactor is only the latest project in that vein.
As far as the significance of his discovery, they note that the conventional "fermentation reactions that produce ethanol take place in water, and removing every last drop of water from a batch of ethanol takes plenty of energy." And this ethanol isn't like vodka, ethanol used for internal combustion engines has to contain nearly 100% alcohol. Going from ethanol to its diluted form of vodka ("wet" ethanol) eliminates many energy intensive steps. However, don't expect a rosy future. They note:
For one thing, it matters where the hydrogen comes from. If its source is a plant like corn or soybeans, then the real powerhouse is the sun. But if the U.S., let alone the world, were to switch to ethanol and biodiesel, farmers would have to supply much more corn or soybeans, and the effort of growing these crops would consume extra energy and may devour more pristine land. Also, corn requires high inputs of nitrogen fertilizer. Crops like switchgrass or hybrid poplar have been suggested as possible hydrogen sources that would exact a lesser environmental cost. Nevertheless, the question of how to supply hydrogen without despoiling the environment will probably not be answered soon. Wind power, although sporadic, can generate electricity to extract hydrogen from water and may ease the situation somewhat.

However hydrogen is generated, it's of little use without fuel cells to extract its energy. That technology is just now moving from infancy to the demonstration stage.

"Once fuel cells become popular, the hydrogen reactor technology will be a very competitive option," says Schmidt. But the combination of his reactor and fuel cells won't replace current technologies until a new infrastructure is ready.

"The hydrogen economy means cars and electricity powered by hydrogen," he says. "But hydrogen is hard to come by. You can't pipe it long distances. There are a few hydrogen fueling stations, but they strip hydrogen from methane on site. It's expensive, and because it uses fossil fuels it increases carbon dioxide emissions, so it's only a short-term solution until renewable hydrogen is available."
More recent news on Schmidt's discovery here and here. A good review which includes Lanny's idea, but I somehow missed is archived at PeakOil.


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