Posted on 05/17/2007 4:09:52 AM PDT by saganite
WEST LAFAYETTE, INDIANA, USA -- A Purdue University engineer has developed a method that uses an aluminum alloy to extract hydrogen from water for running fuel cells or internal combustion engines. The technique could be used to replace gasoline, though it is not quite cost-competitive yet.
The method makes it unnecessary to store or transport hydrogen - two major challenges in creating a hydrogen economy, said Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue who invented the process.
"The hydrogen is generated on demand, so you only produce as much as you need when you need it," said Woodall, who presented research findings detailing how the system works during a recent energy symposium at Purdue.
The technology could be used to drive small internal combustion engines in various applications, including portable emergency generators, lawn mowers and chain saws. The process could, in theory, also be used to replace gasoline for cars and trucks, he said.
Hydrogen is generated spontaneously when water is added to pellets of the alloy, which is made of aluminum and a metal called gallium. The researchers have shown how hydrogen is produced when water is added to a small tank containing the pellets. Hydrogen produced in such a system could be fed directly to an engine, such as those on lawn mowers.
"When water is added to the pellets, the aluminum in the solid alloy reacts because it has a strong attraction to the oxygen in the water," Woodall said.
This reaction splits the oxygen and hydrogen contained in water, releasing hydrogen in the process.
The gallium is critical to the process because it hinders the formation of a skin normally created on aluminum's surface after oxidation. This skin usually prevents oxygen from reacting with aluminum, acting as a barrier. Preventing the skin's formation allows the reaction to continue until all of the aluminum is used.
The waste products are gallium and aluminum oxide, also called alumina. Combusting hydrogen in an engine produces only water as waste.
As a catalyst, the gallium is not consumed, and hence does not need to be replenished. The alumina can be recharged in a separate process, preferably using renewable energy.
The Purdue Research Foundation holds title to the primary patent, which has been filed with the U.S. Patent and Trademark Office and is pending. An Indiana startup company, AlGalCo LLC., has received a license for the exclusive right to commercialize the process.
Woodall discovered that liquid alloys of aluminum and gallium spontaneously produce hydrogen if mixed with water while he was working as a researcher in the semiconductor industry in 1967. The research, which focused on developing new semiconductors for computers and electronics, led to advances in optical-fiber communications and light-emitting diodes, making them practical for everything from DVD players to automotive dashboard displays. That work also led to development of advanced transistors for cell phones and components in solar cells powering space modules like those used on the Mars rover, earning Woodall the 2001 National Medal of Technology from President George W. Bush.
"I was cleaning a crucible containing liquid alloys of gallium and aluminum," Woodall said. "When I added water to this alloy - talk about a discovery - there was a violent poof. I went to my office and worked out the reaction in a couple of hours to figure out what had happened. When aluminum atoms in the liquid alloy come into contact with water, they react, splitting the water and producing hydrogen and aluminum oxide.
"Gallium is critical because it melts at low temperature and readily dissolves aluminum, and it renders the aluminum in the solid pellets reactive with water. This was a totally surprising discovery, since it is well known that pure solid aluminum does not readily react with water."
"No toxic fumes are produced," Woodall said. "It's important to note that the gallium doesn't react, so it doesn't get used up and can be recycled over and over again. The reason this is so important is because gallium is currently a lot more expensive than aluminum. Hopefully, if this process is widely adopted, the gallium industry will respond by producing large quantities of the low-grade gallium required for our process. Currently, nearly all gallium is of high purity and used almost exclusively by the semiconductor industry."
Woodall said that because the technology makes it possible to use hydrogen instead of gasoline to run internal combustion engines it could be used for cars and trucks. In order for the technology to be economically competitive with gasoline, however, the cost of recycling aluminum oxide must be reduced, he said.
"Right now it costs more than $1 a pound to buy aluminum, and, at that price, you can't deliver a product at the equivalent of $3 per gallon of gasoline," Woodall said.
However, the cost of aluminum could be reduced by recycling it from the alumina using a process called fused salt electrolysis. The aluminum could be produced at competitive prices if the recycling process were carried out with electricity generated by a nuclear power plant or windmills. Because the electricity would not need to be distributed on the power grid, it would be less costly than power produced by plants connected to the grid, and the generators could be located in remote locations, which would be particularly important for a nuclear reactor to ease political and social concerns, Woodall said.
"The cost of making on-site electricity is much lower if you don't have to distribute it," Woodall said.
The approach could enable the United States to replace gasoline for transportation purposes, reducing pollution and the nation's dependence on foreign oil. If hydrogen fuel cells are perfected for cars and trucks in the future, the same hydrogen-producing method could be used to power them, he said.
"We call this the aluminum-enabling hydrogen economy," Woodall said. "It's a simple matter to convert ordinary internal combustion engines to run on hydrogen. All you have to do is replace the gasoline fuel injector with a hydrogen injector."
Even at the current cost of aluminum, however, the method would be economically competitive with gasoline if the hydrogen were used to run future fuel cells.
"Using pure hydrogen, fuel cell systems run at an overall efficiency of 75 percent, compared to 40 percent using hydrogen extracted from fossil fuels and with 25 percent for internal combustion engines," Woodall said. "Therefore, when and if fuel cells become economically viable, our method would compete with gasoline at $3 per gallon even if aluminum costs more than a dollar per pound."
The hydrogen-generating technology paired with advanced fuel cells also represents a potential future method for replacing lead-acid batteries in applications such as golf carts, electric wheel chairs and hybrid cars, he said.
The technology underscores aluminum's value for energy production.
"Most people don't realize how energy intensive aluminum is," Woodall said. "For every pound of aluminum you get more than two kilowatt hours of energy in the form of hydrogen combustion and more than two kilowatt hours of heat from the reaction of aluminum with water. A midsize car with a full tank of aluminum-gallium pellets, which amounts to about 350 pounds of aluminum, could take a 350-mile trip and it would cost $60, assuming the alumina is converted back to aluminum on-site at a nuclear power plant.
"How does this compare with conventional technology? Well, if I put gasoline in a tank, I get six kilowatt hours per pound, or about two and a half times the energy than I get for a pound of aluminum. So I need about two and a half times the weight of aluminum to get the same energy output, but I eliminate gasoline entirely, and I am using a resource that is cheap and abundant in the United States. If only the energy of the generated hydrogen is used, then the aluminum-gallium alloy would require about the same space as a tank of gasoline, so no extra room would be needed, and the added weight would be the equivalent of an extra passenger, albeit a pretty large extra passenger."
The concept could eliminate major hurdles related to developing a hydrogen economy. Replacing gasoline with hydrogen for transportation purposes would require the production of huge quantities of hydrogen, and the hydrogen gas would then have to be transported to filling stations. Transporting hydrogen is expensive because it is a "non-ideal gas," meaning storage tanks contain less hydrogen than other gases.
"If I can economically make hydrogen on demand, however, I don't have to store and transport it, which solves a significant problem," Woodall said.
Researchers Succeed In Fueling UpThe principle behind fuel cells is not new-it was discovered in 1839... Basically, a fuel cell is a device-think of it as a high-tech battery-that converts the energy of a fuel (hydrogen, natural gas, etc.) and an oxidant (air or oxygen) into useable electricity... There are no moving parts and it produces little noise. Unlike traditional combustion engines that currently dominate the energy market, fuel cells do not produce any particulate matter, nitrogen or sulfur oxides; when fueled by pure hydrogen, they have only heat and water as by-products... To date, hydrogen has been the conventional fuel for a fuel cell. But practical generation and storage of hydrogen has been a problem-it's expensive and inefficient. The model developed by Gorte's team aims to get around this dilemma... Previous attempts to use hydrocarbon fuels to run a solid-oxide fuel cell failed because the electrochemical process that generates electricity caused a buildup of carbon, which ruined the cell. In a solid-oxide fuel cell, oxygen anions are transported through an oxide membrane and react with the fuel at the anode... The Penn researchers were looking for an anode material that did not result in fouling... Eventually, they settled on a composite of copper and ceria. Ceria is an important catalytic component of automotive catalysis, which is why the researchers focused on its properties... Says Gorte, "Running a car is a transient process and you've got to have a pretty big fuel cell to power it, something on the order of 50kw as opposed to a 5kw cell to power a house, for instance." ...At least one major automotive manufacturer is seriously studying this technology... Their work has generated a great deal of excitement and was touted in Nature magazine (3/16/00). Professor Gorte has been interviewed by MSNBC.
by Jane Brooks
Don’t worry about this.
American car companies will continue to make big heavy lumbering V-8 gas powered cars.
Europe will have a hydrogen powered speedster on the market by next March.
Chrysler will be sold again to Europeans, by the end of next year.
Am I wrong?
Whatever happened to American innovation?
Why are we stuck?
I blame it on first the education system and second the lawyers.
You misunderstand me. It's not that I lack the vision for new transportation technology; rather, I think that by the time we got all the issues resolved satisfactorily to make this particular technology viable, we will have already solved the problem of cheap portable energy with other methods, rendering this approach moot.
If you think Europeans can out innovate us you’ve been drinking some koolaid I’m not familiar with. You screen name is appropriate.
And the process of emptying the beer cans will produce a water source. It's a perfect fuel system.
Been doing some musing over this. Years ago, just for fun, did the aluminum strips/lye-in-water/balloon number. It WORKS at producing H2 of course but how would it stack up against your Ga/Al/H2O unit in terms of initial cost for the system and over the long haul?
Lye is widely available right now, as is scrap aluminum; one doesn’t need to wait 5 years and pay $50K for a mass-marketed Ga/Al unit-system, wheather w/an IC engine or fickle H2/air fuel cell. This could be an item made by Mother Earth Home tinkerers, the same guys who do their own solar systems(the sun don’t shine in nuclear winter).
So, where does one find hydrogen IC fuel injectors?
I told the group about lye when it first formed. Students
often do that with 2-liter pop bottles which usually gets the police riled up. Strong lye might be a problem in
a wreck if it gets loose or splashed on someone.
For hydrogen injectors, a propane carb should work with
minor changes. It may even be possible to have a carb
without a throttle plate due to the very wide ignition
limits of H2. Big volumetric effeciency boost.
I havent heard much on the glass BB’s to store H2
for a few years now.. anybody else heard?
For a nuke winter, biomass gasifiers make more
sense. They don’t need an infrastructure in place
to ship the fuel and recycle the spent fuel for
regeneration.
I havent been to a group meeting for 2-3 months.
I just volunteered for awhile to give ‘em a hand.
I have 3000 computers to worry about for my
‘real’ job...
—ghg
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