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Jerry Woodall, a professor at Purdue University invented the new alloy production process, promising affordable, easy hydrogen.  (Source: Purdue University)

Pictures of the alloy in water, reacting to produce hydrogen, as evidenced by bubbling.  (Source: Purdue University)

The byproduct of the process is a recyclable mix of aluminum and gallium-indium-tin ores.  (Source: Purdue University)

Here a Purdue researcher uses the hydrogen produced by the process to power an internal combustion engine.  (Source: Purdue University)
While some hydrogen research focuses on simulating nature, a new metal reagent developed by Purdue University promises economic viability

Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue University, is firmly ground in the world of commercial production.  When he began researching ways to improve hydrogen production using aluminum reagents, his goal was simple -- if it wasn't commercially viable, it wasn't a success.

While recent researchers have reported significant breakthroughs in fields such as synthetic photosynthesis and microbial hydrogen production, these methods currently are too inefficient to currently be feasible as a non-subsidized fuel alternative.  While these methods are exciting in that they may one day lead to cleaner and more effective energy production, many agree that the time for hydrogen is now, and waiting for theoretical methods is simply impractical.

Fortunately Purdue's Woodall developed a more down to Earth method of hydrogen production that promises a feasible infrastructure and short term commercial viability.  Woodall states, "We now have an economically viable process for producing hydrogen on-demand for vehicles, electrical generating stations and other applications."

The key to the method is a new aluminum reagent, which Woodall invented.  The new reagent is composed of 95 percent aluminum and then a critical 5 percent mixture of gallium, indium and tin to improve its reactive character.  Previous similar alloys used far more gallium, which is very expensive.  By cutting down the gallium, Woodall greatly reduced the costs of hydrogen production.

When the new alloy is exposed to water, it reacts to create hydrogen gas and oxygen.  The oxygen then bonds to the aluminum to form aluminum oxide, also known as alumina.  It is cheaper to recycle alumina back to aluminum than it is to refine aluminum from bauxite ore, which is another element contributing to its efficiency.  Woodall illuminates, "After recycling both the aluminum oxide back to aluminum and the inert gallium-indium-tin alloy only 60 times, the cost of producing energy both as hydrogen and heat using the technology would be reduced to 10 cents per kilowatt hour, making it competitive with other energy technologies."

Control of the microscopic structure of the solid aluminum and the gallium-indium-tin alloy mixture is critical to the technology's success.   The mixture is a "two-phase" mixture, meaning that it features abrupt changes in composition between one constituent to another.  Woodall explains this challenge stating, "This is because the mixture tends to resist forming entirely as a homogeneous solid due to the different crystal structures of the elements in the alloy and the low   melting point of the gallium-indium-tin alloy.  I can form a one-phase melt of liquid aluminum and the gallium-indium-tin alloy by heating it. But when I cool it down, most of the gallium-indium-tin alloy is not homogeneously incorporated into the solid aluminum, but remains a separate phase of liquid.  The constituents separate into two phases just like ice and liquid water."

Researchers had two options -- fast cooling to leave separate alloys or slow cooling to yield a single solid alloy brick.  At first they tried fast cooling, which required a puddle of gallium-indium-tin to initiate the reaction.  However, when they turned to the slow-cooled alloy, they were impressed to discover that it reacted just as well, or better, eliminating the need for the liquid gallium-indium-tin alloy.  Woodall adds, "That was a fantastic discovery.  What used to be a curiosity is now a real alternative energy technology."

The Purdue team is currently completing work on developing a production method to produce briquettes of the alloy.  These briquettes could be dropped into a tank of water, producing pure hydrogen.  This would eliminate both the need for hydrogen storage and hydrogen transportation, two critical obstacles for the hydrogen industry. 

The gallium-indium-tin alloy in the process is inert and is able to be recovered with almost 100 percent efficiency.  Woodall says even the less efficient aluminum recycling produces much less carbon emissions than traditional fuel.  He states, "The aluminum oxide is recycled back into aluminum using the currently preferred industrial process called the Hall-Héroult process, which produces one-third as much carbon dioxide as combusting gasoline in an engine."

In order to fully realize the technology on a national scale for fuel use, alumina recycling infrastructure would need to be dramatically expanded.  Additionally, gallium-indium-tin recycling would need to be added.  This infrastructure would be expensive, but according to Woodall "the economic risk is large, but the potential payoff is also large."

Woodall won the 2001 National Medal of Technology, the highest award for technological achievement in the U.S.  Woodall his fellow researchers will present their findings on Feb. 26, 2008 at the Materials Innovations in an Emerging Hydrogen Economy conference in Cocoa Beach, Fla.  The alloy production process's primary patent title is owned by the Purdue Research Foundation.  Purdue has licensed the technology to an Indiana startup company, AlGalCo LLC., which Purdue hopes will be the first company to implement the technology commercially.

Purdue's solution is similar to the University of Leeds' new method of producing hydrogen from biofuel waste sludge, in that both solutions are economically feasible, but require the development of production infrastructures.  However the new method from Purdue can make hydrogen from a far more plentiful source -- pure water.


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RE: unsure
By pauluskc on 2/21/2008 3:37:34 PM , Rating: 2
why not just convert the oil pipelines to hydrogen pipelines? there's already a huge infrastructre in place to distribute gasoline that could be used similarly for hydrogen.

maybe.


RE: unsure
By Cattman on 2/21/2008 3:56:11 PM , Rating: 2
Because hydrogen leaks out of everything in gaseous state. It will actually leak out of a sealed gas bottle. The atoms are so small they permeate everything. A weld or joint that is liquid tight will probably not be hydrogen tight. Keeping it liquid would be a nightmare as well.


RE: unsure
By FITCamaro on 2/21/2008 4:26:51 PM , Rating: 1
I'm no chemist, but I don't think hydrogen can leak through solid metal. A joint yes. But if you put hydrogen in a sealed metal container, I don't see it getting out.

Regardless of the practicality of this, the real problem is getting the oil industries to embrace it. Because really, they're the ones who have to. The government isn't going to put down the cash to replace oil. It's not really their business to either. And the oil industry is really the only ones with the billions it'll cost to convert our gasoline base infrastructure to a hydrogen one.

Even if it does happen, then the only downside is that a car is going to go far fewer miles on a gasoline tank sized hydrogen fuel cell than it would go on the tank of gas since you have to use a lot more hydrogen to get the same bang as with gas.


RE: unsure
By SolarHydrogen on 2/21/2008 4:35:53 PM , Rating: 3
The issue with piping hydrogen is that it reacts with the metal, turning it brittle and susceptible to cracking.


RE: unsure
By geddarkstorm on 2/21/2008 4:45:04 PM , Rating: 2
It diffuses through some metals--especially steel--and can form pockets of hydrogen gas inside microscopic cavities. http://en.wikipedia.org/wiki/Hydrogen_embrittlemen...

I don't think it'd leak out at a rate of or in the sense of noticable loss of volume during piping. It'll just slowly destroy the pipes. It is a potential issue, which is why this reactive alloy technology is so cool and great.


RE: unsure
By Chernobyl68 on 2/21/2008 5:45:29 PM , Rating: 2
great article, thanks for the link.


RE: unsure
By drwho9437 on 2/21/2008 5:25:48 PM , Rating: 2
You are right you aren't. Hydrogen diffuses through "solids" at fairly low temperatures. The diffusion constant is just proportional to temperature, so at 300K it isn't what it is at say 600K but if you are going to have a lot of it, a lot of it will get out. Hydrogen is one of the hardest things to hold on to.


RE: unsure
By Oregonian2 on 2/21/2008 5:44:06 PM , Rating: 2
Aren't pipelines always being tested for microcracks (etc)? Seems like things would leak. But it's more than that, recall that for energy density the hydrogen has to be at really high pressures, something an oil pipeline wouldn't have been built for. Hydrogen also may be a bit more volatile than crude oil.


RE: unsure
By Keeir on 2/21/2008 6:19:22 PM , Rating: 2
Your also no Structural Analyst. Or Mechancal Engineer.

All gases create pressure vessal situations. To create the required density through put of Hydrogen, well, the gas will need to be at significant pressure. That pressure will put alot of strain (that is signiciantly different than Oil mass loading) on current pipe lengths and joints. The pumping mechanisms that work well for oil, they are not the most efficient for Hydrogen.

Then, the "last mile" that takes the hydrogen to "filling station"... the truck would need to be very strong indeed to withstand the PSI. To get current amount of energy storage as in a modern gastank type volume... that volume would be at 10,000 psi!. Aircraft typically operate at ~10 psi interal gage pressure for a point of reference.

Sorry folks, entire pipeline/gasoline infrastructure would need to be examined, reanalyzed, and potentially replaced to use it for Hydrogen transportation. Thats before Hydrogen Embrittlement and other issues.


RE: unsure
By FITCamaro on 2/22/2008 8:46:26 AM , Rating: 2
quote:
Your also no Structural Analyst. Or Mechancal Engineer.


I didn't claim to be. I'm a simple programmer. We leave those gases and stuff to the smart people.


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