UA Researchers Named to Presidential Research Initiative
by Elizabeth M. Smith
The record rise of gasoline prices during 2004 underscored for consumers a need scientists have been interested in for some time — the search for alternative fuel sources. The University of Alabama is on the cutting edge of that search and is working toward innovative solutions to make hydrogen-powered cars and trucks a reality.
As part of President George W. Bush’s Hydrogen Research Initiative, the Capstone has been named a partner in a Grand Challenge Center for Chemical Hydrogen Storage. The benefits of hydrogen and fuel cell technology will be cleaner air, economic growth and less dependence on foreign oil.
The Center, led by Los Alamos National Laboratory and co-led by Pacific Northwest National Laboratory, requested $6 million in funding annually for five years. It is part of Secretary of Energy Spencer Abraham’s recently announced $350 million in science and research projects, which represents nearly one-third of the president’s $1.2 billion commitment in research funding to bring hydrogen and fuel cell technology from the laboratory to the showroom. UA’s share will be at least $250,000 a year for five years.
Dr. Anthony J. Arduengo, Saxon Professor of Chemistry, and Dr. David A. Dixon, Ramsay Professor of Chemistry and formerly of the Pacific Northwest National Laboratory, are the principal investigators with Dr. Joseph Thrasher, professor and chemistry department chair, serving as the co-principal investigator on the project.
All three UA scientists are known internationally for their research. For this project, Arduengo’s focus will be on synthesizing new compounds capable of taking up and releasing hydrogen on demand; Dixon will study the energetics of hydrogen storage systems and help design molecules that will provide maximum hydrogen storage capacity per unit weight by using advanced computational methods; and Thrasher’s work will seek out materials to manage heat exchange during hydrogen uptake and release and that provide for effective hydrogen transport.
“We want to be able to develop a working prototype fairly early in the project,” Arduengo says. “It may not be the optimal system, but it will allow us to address not only the fundamental problems of hydrogen storage, hydrogen transport and heat transport but also the questions of system integration. The research all three of us are leading will move along hand-in-hand.”
Hydrogen vs. Gasoline
Why hydrogen? Mother Nature made a simple fuel in hydrogen. It burns with oxygen in the air to produce water, is not harmful to release into the environment, and there are no byproducts.
“In fact, the water that comes out of fuel cells is normally very pure,” Arduengo says. “The Apollo space program used fuel cells for power, and the water produced from the fuel cells was used as drinking water by the astronauts in space.”
Energy from hydrogen is produced in a simple chemical reaction. Chemically combined in a fuel cell with oxygen, electrical energy is produced, harnessed and can be used to power an electric motor or other electrical device. Hydrogen can also be burned in air in the conventional sense to produce heat. No other fuel offers the flexibility of hydrogen.
The United States has natural resources that can be used to produce hydrogen, and the use of these resources will make the country less dependent on foreign oil. In that way, the use of hydrogen as a fuel has significant national security implications.
Gasoline use comes with danger signs and warnings, and while the world has decided it is worth the risks, the use of hydrogen could provide fewer dangers. In addition, the nation imports enormous amounts of hydrocarbon-based fuels.
“If you can imagine a gasoline spill, it spills onto the ground and spreads out,” Arduengo says. “If, in the process of that spill, there were to be an accident that caused it to inflame — because gasoline is a heavier-than-air material — it will burn in the same spot and expose people and equipment to that flame and heat.
“Hydrogen, on the other hand, is a lighter-than-air gas,” he continued. “So, when it is released it tends to move up into the atmosphere and away from individuals on the ground. The chances of ignition are reduced, and, if it does ignite, hydrogen is lighter than air and is moving away from the accident or spill.”
Storage Issues
Two of the main components the scientists will be studying are storage and transportation. Literally, how will the hydrogen be moved from point A to point B, and how will it be stored? For automotive use, the easiest way is a fuel tank to provide a stored amount of hydrogen fuel. The key to this is weight.
The scientists will conduct experiments to determine what combination of hydrogen and other compounds will provide the greatest stability and highest energy content for the weight of the tank that must be transported. Dixon says combinations of boron and nitrogen appear to be a good choice because these two light elements can carry quite a bit of hydrogen.
“And that’s the key piece: How can I get a lot of hydrogen onto a compound and have it be stable enough to store underneath a car in a tank?” Dixon says. “If there’s not a great enough percent weight of hydrogen in the chemical compound, it literally will be too heavy and would cost too much to carry around.”
A gallon of gas weighs between 6 and 8 pounds, and a fill up for a 15 gallon tank weighs between 90 and 120 pounds.
“No one’s going to want to bring that up to 500 pounds,” he continues. “It would make your car less efficient and be a waste of energy. So what we have to come up with are low weight materials that release hydrogen safely and on demand without a lot of energy being required to release the hydrogen or to make the fuel, so we can keep it a cost-effective process.”
Thrasher’s work on heat exchange will impact both of these areas. “A chemical hydrogen storage system will likely be a solid material,” he says. “In the refueling process, heat will be given off, and there has to be a way to dissipate that heat. Fluorocarbon materials will do a very good job of this because they have excellent heat capacities and a high solubility of hydrogen.”
Other Applications
In addition to acting as a fuel source for automobiles, other uses for hydrogen could be home heating or the local production of electricity.
“If hydrogen were ever to be used in the economy to replace natural gas or propane for the home, you can imagine either delivering that hydrogen through a pipeline or through a tank,” Arduengo says.
So, can today’s natural gas pipelines be used to transport hydrogen? UA scientists say, “maybe.”
Hydrogen is such a small molecule that it has a tendency to leak out of systems where nothing else will leak. It even finds holes where there are seemingly none.
According to Arduengo, steel, which is perfectly good for containing methane, is not so good for containing hydrogen because eventually some steels will become fragile after prolonged exposure to hydrogen, as the hydrogen can creep into the microscopic cracks found in any material.
There is a lot of plastic in today’s systems, as natural gas companies have been lining older steel and laying new pipe with polyethylene. Arduengo says permeability will again have to be studied for these plastics.
“There will be some small diffusion of hydrogen, but the question is how much, and is it enough to worry about, or is it just a small loss?” Arduengo says. “I think you can probably find people to support both sides of that question. It’ll just mean looking at the system and seeing what sort of pressures can be used.”
Research as a Teaching Tool
All three researchers say this piece of science and technology will be a fantastic teaching tool for UA students.
“Our No. 1 objective at the University is to produce and train nationally and internationally competitive students to enter the workforce,” Thrasher says.
“The problem of solving the hydrogen transport problem gives us a great opportunity to train students in a relevant area of technology,” Arduengo says. “I think it’s a tremendous opportunity to help us train these new generations of scientists while, in fact, being able to come up with a creative solution to an important ‘real world’ problem.”
Dixon agrees. “That’s what I think is unique, our students will be getting a fundamental science understanding, and they’ll also be able to apply it to a real problem and work in a team environment.”
Thrasher adds that before the general public puts fuel cells in their cars and hydrogen in their tanks, the public is going to have to accept these changes. Students trained at UA will enter all facets of science: grade school and high school science teachers, professors, and research and development at companies around the state and the nation.
“We need people in all these areas talking to their neighbors and friends about this new science application to get the word out,” he says. “We’ll have to show that this is a safe and valuable technology, so they’ll accept it when it comes along.”
UA will be working in conjunction with scientists from Los Alamos National Laboratory and Pacific Northwest National Laboratory, U.S. Borax, Intematix, Millennium Cell and Rohm and Haas, as well as the following universities: Penn State, The University of California, Davis, University of Pennsylvania, UCLA and the University of Washington.
Further Reading