I saw this research in a documentary over the weekend. Basically, aluminum reacts with water to release hydrogen. The alumina residue can be cheaply recycled back into aluminum in existing bauxite refineries -- it behaves like extremely high-grade ore. To get around the oxide layer that normally protects aluminum from corrosion, you alloy the aluminum with gallium. The gallium just prevents the oxidation skin, and is inert with respect to the H2 production, and thus can be recovered and reused efficiently.Funny how higher prices for gas spur innovation in transportation, isn't it? It's almost as if the law of supply and demand is working, or something.
And where do we get the gallium? It turns out gallium is a waste product from aluminum refining operations.
The big obstacle for hydrogen vehicles is how to store large quantities of hydrogen safely. Producing H2 on demand solves that problem. You create the H2 by metering water at the desired rate into a bed of aluminum-gallium pellets.
One article I found says that with *today's* aluminum processing facilities, that is, no assumption of a more efficient process, this makes hydrogen roughly equivalent in cost to $3.60/gallon gasoline if you run it in a converted internal combustion engine. If you use a fuel cell to run an electric vehicle instead, it's a lot cheaper, but that's not an easy retrofit of existing cars.
Monday, April 7, 2008
Aluminum and the Hydrogen Car
My friend Scott sent this out, and it was too good not to share in its entirety.