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The team used xylose -- a simple plant sugar

Virginia Tech researchers have found a way to produce large amounts of hydrogen inexpensively using a simple plant sugar.

Y.H. Percival Zhang, study leader and an associate professor of biological systems engineering at Virginia Tech, and his team have produced large quantities of hydrogen in an effort to lessen the dependence of fossil fuels.

Zhang and his team used xylose in the study, which is a sugar first isolated from wood. Not only is this form of hydrogen production inexpensive and environmentally friendly, but it can also occur using any source of biomass. 

Up until now, producing hydrogen gas from biomass was a costly process that didn't yield very much in the end.


For this study, Zhang and his team liberated the hydrogen under normal atmospheric pressure and mild reaction conditions at 122 degrees. A group of enzymes -- which were isolated from various microorganisms at extreme temperatures -- were used as biocatalysts to release the hydrogen.

The team used xylose to release the hydrogen, which hasn't been used much in the past because most scientists use natural or engineered microorganisms. These cannot create large quantities of hydrogen because the microorganisms grow and reproduce instead of splitting water molecules for the creation of pure hydrogen.

The energy stored in Xylose splits water molecules, thus creating very pure hydrogen that can be used by proton-exchange membrane fuel cells.

The team separated some of the enzymes from their native microorganisms to create a special enzyme mixture.  When the enzymes were combined with xylose and a polyphosphate, a large amount of hydrogen was liberated from the xylose.

In fact, the team produced about three times as much hydrogen as other hydrogen-producing microorganisms.

“Our new process could help end our dependence on fossil fuels,” said Zhang. "Hydrogen is one of the most important biofuels of the future.”

Source: Virginia Tech News



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RE: One problem...
By kyuuketsuki on 4/7/2013 7:11:47 PM , Rating: 3
Where are you getting all those numbers for the efficiency of various stages of hydrogen production? Seems to me like you're just pulling those out of thin air. Plus, even if they are accurate, you're obviously not taking into account the efficiency of the new process described in the article, since it's not a current manufacturing process.

Plus, what are the numbers for the various stages of extracting/transporting/burning gasoline and ethanol? You claim that both are more efficient than hydrogen, yet don't provide any proof.

Really, if hydrogen can be produced efficiently, then the only issue left is storage, which is an engineering problem that would be solved fairly quickly, I think, once hydrogen is feasible as a fuel in the first place. We've had tanks full of explosive fuel in our vehicles forever, and we already have vehicles running on a pressurized flammable gas (CNG).


RE: One problem...
By Solandri on 4/7/2013 9:49:33 PM , Rating: 1
quote:
Where are you getting all those numbers for the efficiency of various stages of hydrogen production? Seems to me like you're just pulling those out of thin air.

I'm getting them from years of mulling over and learning about these different technologies. 40% is about the efficiency of a modern coal plant. Coal produces most of our electricity.

60-65% is the efficiency of electrolysis of water. You can get higher - up to 80%-95%, but that usually comes at the cost of (much) slower conversion rates. Unfeasible for wide-scale production of hydrogen.
http://en.wikipedia.org/wiki/Electrolysis_of_water...

quote:
Plus, even if they are accurate, you're obviously not taking into account the efficiency of the new process described in the article, since it's not a current manufacturing process.

Well that was my point. You can't just point to this new hydrogen production method and say "Look! Hydrogen is free now!" You have to compare it against an alternative use of that plant matter - conversion into ethanol. You always have to compare against opportunity costs, not against a vacuum.

quote:
Plus, what are the numbers for the various stages of extracting/transporting/burning gasoline and ethanol? You claim that both are more efficient than hydrogen, yet don't provide any proof.

Isn't it obvious? Gasoline and ethanol can be stored and transported as a liquid at room temperature and normal atmospheric pressure. Hydrogen either needs to be compressed or chilled. And due to H2 being a tiny molecule, hoses and fittings which can carry gasoline and alcohol without leaking cannot carry hydrogen without leaking. So the storage and transportation cost of hydrogen will always be higher than for gasoline and ethanol.

quote:
Really, if hydrogen can be produced efficiently, then the only issue left is storage, which is an engineering problem that would be solved fairly quickly

If you know anyone who works in a lab which uses H2 gas (or He gas, which is an even smaller molecule), please have a chat with them. The stuff leaks out of even well-designed storage tanks and hoses/fittings.

The entire reason petroleum and alcohols are preferred as fuels is because they bind hydrogen into a molecule which is much easier and safer to store and handle, while only giving up a little of the energy. The difficulty with storing and transporting hydrogen gas is driving some hydrogen fuel cell researchers to try out methane and methanol as fuels instead of pure hydrogen gas. Well, if you keep going down that path, you arrive right back at where we started - petroleum and alcohol as the optimal way to store and transport energy in hydrogen atoms.


RE: One problem...
By Alexvrb on 4/7/2013 10:55:02 PM , Rating: 2
Up until now, producing hydrogen gas from biomass was a costly process that didn't yield very much in the end. But now... with this latest breakthrough... producing hydrogen gas from biomass is a costly process that yields a bit more.


RE: One problem...
By Kyuu on 4/8/2013 1:03:46 AM , Rating: 2
Okay... fair enough. Thanks for the info.

It looks like there are at least a couple of promising technologies under development for mobile hydrogen storage, though, like cryo-compression and metal organic frameworks.


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