A pair of University of Wisconsin researcher claim they have developed a more efficient and less polluting way to convert hydrocarbons into hydrogen.
Carbon monoxide, or CO, has long been a major technical barrier to the efficient operation of fuel cells. But now, chemical and biological engineers at UW-Madison have not only cleared that barrier - they also have discovered a method to capture carbon monoxide's energy.
To be useful in a power-generating fuel cell, hydrocarbons such as gasoline, natural gas or ethanol must be reformed into a hydrogen-rich gas. A large, costly and critical step to this process requires generating steam and reacting it with carbon monoxide (CO). This process, called water-gas shift, produces hydrogen and carbon dioxide (CO2). Additional steps then are taken to reduce the CO levels further before the hydrogen enters a fuel cell.
James Dumesic, professor of chemical and biological engineering, postdoctoral researcher Won Bae Kim, and graduate students Tobias Voitl and Gabriel Rodriguez-Rivera eliminated the water-gas shift reaction from the process, removing the need to transport and vaporize liquid water in the production of energy for portable applications.
The team, as reported in the Aug. 27 issue of Science, uses an environmentally benign polyoxometalate (POM) compound to oxidize CO in liquid water at room temperature. The compound not only removes CO from gas streams for fuel cells, but also converts the energy content of CO into a liquid that subsequently can be used to power a fuel cell.
Note that their focus is on the development of supporting technologies aimed at making portable fuel cells more practical. Their approach does not generate any energy and they need hydrocarbon fuels to start with. Still, conversion of hydrocarbons to hydrogen to burn in fuel cells might some day make cars more efficient in their use of liquid hydrocarbons. At the very least their appoach might provide portable power sources for personal computers and other gadgets humans lug around.
WIth an aim of enabling solar power to be tapped as an economic source of energy a pair of Australian scientists claim they will be able to build solar power driven hydrogen generating titanium oxide ceramics.
Australian scientists predict that a revolutionary new way to harness the power of the sun to extract clean and almost unlimited energy supplies from water will be a reality within seven years.Using special titanium oxide ceramics that harvest sunlight and split water to produce hydrogen fuel, the researchers say it will then be a simple engineering exercise to make an energy-harvesting device with no moving parts and emitting no greenhouse gases or pollutants.
It would be the cheapest, cleanest and most abundant energy source ever developed: the main by-products would be oxygen and water.
"This is potentially huge, with a market the size of all the existing markets for coal, oil and gas combined," says Professor Janusz Nowotny, who with Professor Chris Sorrell is leading a solar hydrogen research project at the University of New South Wales (UNSW) Centre for Materials and Energy Conversion. The team is thought to be the most advanced in developing the cheap, light-sensitive materials that will be the basis of the technology.
"Based on our research results, we know we are on the right track and with the right support we now estimate that we can deliver a new material within seven years," says Nowotny.
The UNSW team opted to use titania ceramic photoelectrodes because they have the right semiconducting properties and the highest resistance to water corrosion.
Solar hydrogen, Professor Sorrell argues, is not incompatible with coal. It can be used to produce solar methanol, which produces less carbon dioxide than conventional methods. "As a mid-term energy carrier it has a lot to say for it," he says.
Okay, seven years is some years out there with obviously a number of technical problems yet to be solved. They haven't proved they can really make their approach work or that their materials will really turn out to be cheap to manufacture. Still, they might succeed.
We need many more teams in research labs working on materials to use solar power to generate hydrogen, electricity, and hydrocarbons (artificial photosynthesis). We also need more teams working on fuel cell technologies and materials for newer lighter types of batteries. Many battery and fuel cell technologies would allow fossil fuels to be burned more efficiently while also acting as enabling technologies for solar power by allowing energy captured by solar technologies to be stored.
|Share |||Randall Parker, 2004 August 26 03:49 PM Energy Tech|