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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 geddarkstorm on 2/21/2008 7:12:17 PM , Rating: 3
This is very interesting. At least to me as well.

Another way of looking at it is that if the 11.6 million tons of aluminum recycled in 1998 fulfilled 40% of the world's demand for aluminum, then that demand was 29 million tons for the year. Cars using 12.7 million tons would make the 1998 levels of world demand for aluminum increase by 70% to 41.7 million tons. Quite the jump in world demand, if this was done for all cars, instantly, overnight. Fortunately, the switch would obviously be gradual. However, one thing to consider is how much new aluminum would have to be added to the system per year, over what would be recycled (loss in conversion, increase in cars, how much we can expand our recycling abilities by)? That I can't begin to speculate on, but it would certainly be less and less with each year, so the picture only gets better as time goes on.

Gasoline has an average density of about 737.22 kg/m³ ( http://en.wikipedia.org/wiki/Gasoline ), or 0.737 kg/l, or 2.79 kg/gallon. "Therefore, in the United States, something like 400 million gallons (1.51 billion liters) of gasoline gets consumed every day" ( http://auto.howstuffworks.com/question417.htm ) which then comes to 1.1 million tons of gasoline used by the US alone per day!

So, on the one hand, based on 1998's standards, our aluminum infrastructure would be strained a bit by the demand if all the cars in the world switched to hydrogen produced by this aluminum alloy reagent right at this moment. Sure, we could put all our recycled amounts immediately into it, but that'd leave all the other sectors needing mined aluminum, meaning an increase of 40% in mining would have to be done. By 1998's standards. However, on the other hand, this isn't going to happen over night for all the cars of the world instantly.

But then, compared to how much gasoline we consume, the amount of aluminum it would take to run our cars on hydrogen via this method would be nothing. Nothing at all, in comparison. By the time this method became wide spread, our infrastructure would be more than capable of handling it (recycling is what would go up mostly, after the initial load of raw aluminum gradually leaked into the hydrogen production pool). Again, none of this would happen over night.

Our figures are probably pretty far off from reality, but they give a good perspective and picture. Just looking at that gasoline consumption.. always leaves me shaking my head in awe. Still, the biggest cost factor, especially initially, will be that 5 percent mixture of gallium, indium and tin. If we use 12.7 million tons of aluminum, that'd be 635,000 tons of that stuff (it can be nearly 100% recycled too, thankfully).

In any case, this has been very interesting to research. Thank you for getting me on this kick. Ultimately, we'll just have to see what comes in the future--if this stuff gets commercialized well, if it is presented to the market in a competitive way against gasoline (i.e. how it's priced and how that changes over time), and how the technology matures.


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