Friday, May 18, 2007
New Process Generates Hydrogen From Aluminum Alloy To Run Engines, Fuel Cells
A promising catalytic process using water and aluminum can produce hydrogen for fuel. Instead of distributing hydrogen and putting it in a tank you would use...water.
Subscribe to:
Post Comments (Atom)
1 comment:
There are some problems with the article. The article states the auto would need 350 lbs of aluminum to run 350 miles. How much water would it need? Well, you would need three water atoms for every two atoms of aluminum to make Aluminum oxide (Al2O3). Aluminum is roughly 27 grams/mole, water is 18 grams/mole--another 3 to 2 factor, so you would need roughly 9/4 as much water by weight as aluminum. Thus you would need approximately 800 lbs of water to provide the hydrogen in addition to the weight of aluminum--that is, the vehicle would need 1150 lbs of fuel to go that 350 miles. (Someone more familiar with such things should check my calculation)
Thus, whoever wrote the article, and the Purdue engineer, are either (a) stupid or (b) ethical as a used car salesman.
There are other things not considered in the article. The water should be distilled water--that is, pure water, or impurities would build up in the recycling process for the aluminum. The biggest problem, however, might be that refining aluminum from aluminum oxide is a very energy-intensive operation. That means it would take a lot of energy (7.5 Kwh per pound) to recycle the aluminum each time. If a service station refueled 50 cars a day for 350 lbs that would be 17,500 lbs of aluminum needing processing each day, or 131 megawatt-hours (5 megawatts/day)--which is roughly equivalent to needing a small nuclear reactor at each service station. Refining aluminum from aluminum oxide produces carbon dioxide as a byproduct; a half-pound of carbon is used for every pound of carbon produced, meaning that same service station would need to deal with a huge volume of carbon dioxide each day.
So--don't mortgage the homestead to invest in this technology just yet.
Post a Comment