A Different Method of Producing Hydrogen on Demand
Earlier this week I wrote about a method of using an aluminum and gallium alloy and water to produce hydrogen on demand. By the middle of the week, news came out of Virginia Tech of another means of producing hydrogen on demand.
In this research, conducted by scientists at Virginia Tech, Oak Ridge National Laboratory and the University of Georgia, polysaccharides from biomass react with a combination of 13 enzymes not found together in nature and water to yield hydrogen and carbon dioxide. A 12-gallon tank could hold 27 kg of starch, the equivalent of 4 kg of hydrogen. The range would be over 300 miles.
This biomass is the same sort of stuff scientists are using to turn into ethanol, but this system is far more efficient, as researcher Y. H. Percival Zhang notes:
"What is more important, the energy conversion efficiency from the sugar-hydrogen-fuel cell system is extremely high--greater than three times higher than a sugar-ethanol-internal combustion engine," Zhang said. "It means that if about 30 percent of transportation fuel can be replaced by ethanol from biomass as the DOE proposed, the same amount of biomass will be sufficient to provide 100 percent of vehicle transportation fuel through this technology."
Like the method I wrote about earlier this week, this process of producing hydrogen on demand eliminates the difficulties of storing and transporting hydrogen. The costs of the hydrogen produced is within Department of Energy (DOE) goals, and the energy storage density of the starch is higher than DOE goals.
The research paper is available online without subscription at the Public Library of Science.
Comments (4)
"to yield hydrogen and carbon dioxide"
I'm all for reducing purchases of oil from hostile countries, but given that this process still produces CO2 - I don't think does much to help AGW proponents out.
Posted by Patrick Henry | May 25, 2007 8:35 AM
Carbon dioxide? Did you say carbon dioxide was a by-product? Now, tell me again how this is supposed to be an improvement? Oh, yeah. Hydrogen is the fuel.
Posted by Paul | May 25, 2007 9:31 AM
Patrick and Paul - Burning fossil fuels releases "dead" carbon into the atmosphere, carbon that's been trapped underground for millions of years. Using biomass, whether in the form of ethanol, biodiesel or in this process - while the process still releases carbon dioxide, it's carbon that's "live" carbon, still active in the carbon cycle. The process doesn't release any more carbon dioxide than would be released as the biomass decomposed naturally. Thus, the process is considered to be "carbon neutral."
Posted by Laura Hannon | May 25, 2007 9:49 AM
Laura,
If it were possible to grow enough biomass to replace all of the petroleum usage, then it would also be possible to grow that same quantity of biomass and bury it or otherwise neutralize the carbon.
Either approach would have the same net effect on reducing the rise in atmospheric CO2, only the second approach is low tech and does not require massive changes in transportation technology and fuel delivery.
Posted by Patrick Henry | May 25, 2007 10:59 AM