leftchick
02-23-2008, 06:26 AM
Purdue University engineers have developed a new aluminum-rich alloy that produces hydrogen by splitting water and is economically competitive with conventional fuels for transportation and power generation.
http://www.physorg.com/news122655117.html
"We now have an economically viable process for producing hydrogen on-demand for vehicles, electrical generating stations and other applications," said Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue who invented the process.
The new alloy contains 95 percent aluminum and 5 percent of an alloy that is made of the metals gallium, indium and tin. Because the new alloy contains significantly less of the more expensive gallium than previous forms of the alloy, hydrogen can be produced less expensively, he said.
When immersed in water, the alloy splits water molecules into hydrogen and oxygen, which immediately reacts with the aluminum to produce aluminum oxide, also called alumina, which can be recycled back into aluminum. Recycling aluminum from nearly pure alumina is less expensive than mining the aluminum-containing ore bauxite, making the technology more competitive with other forms of energy production, Woodall said.
"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," Woodall said.
The researchers will present findings about the new alloy on Feb. 26 during the conference Materials Innovations in an Emerging Hydrogen Economy, which runs Feb. 24-27 in Cocoa Beach, Fla..
A key to developing the alloy for large-scale technologies is controlling the microscopic structure of the solid aluminum and the gallium-indium-tin alloy mixture.
"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," Woodall said.
The alloy is said to have two phases because it contains abrupt changes in composition from one constituent to another.
"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," Woodall said. "The constituents separate into two phases just like ice and liquid water."
The two-phase composition seems to be critical for the technology to work because it enables the aluminum alloy to react with water and produce hydrogen.
http://www.physorg.com/news122655117.html
"We now have an economically viable process for producing hydrogen on-demand for vehicles, electrical generating stations and other applications," said Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue who invented the process.
The new alloy contains 95 percent aluminum and 5 percent of an alloy that is made of the metals gallium, indium and tin. Because the new alloy contains significantly less of the more expensive gallium than previous forms of the alloy, hydrogen can be produced less expensively, he said.
When immersed in water, the alloy splits water molecules into hydrogen and oxygen, which immediately reacts with the aluminum to produce aluminum oxide, also called alumina, which can be recycled back into aluminum. Recycling aluminum from nearly pure alumina is less expensive than mining the aluminum-containing ore bauxite, making the technology more competitive with other forms of energy production, Woodall said.
"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," Woodall said.
The researchers will present findings about the new alloy on Feb. 26 during the conference Materials Innovations in an Emerging Hydrogen Economy, which runs Feb. 24-27 in Cocoa Beach, Fla..
A key to developing the alloy for large-scale technologies is controlling the microscopic structure of the solid aluminum and the gallium-indium-tin alloy mixture.
"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," Woodall said.
The alloy is said to have two phases because it contains abrupt changes in composition from one constituent to another.
"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," Woodall said. "The constituents separate into two phases just like ice and liquid water."
The two-phase composition seems to be critical for the technology to work because it enables the aluminum alloy to react with water and produce hydrogen.