Of course, there are other roadblocks. Sulfur in the hydrocarbon fuel can contaminate the fuel cell and degrade it. GE and others are working on various pre-treatment processes to keep the contaminant out of the fuel cell. For example, researchers at Tufts University have developed a way to use cerium and lanthanum oxides to remove sulfur. Maria Flytzani-Stephanopoulos, a chemical engineer at Tufts who led development of the scrubber, cautions that while the GE work is impressive, large challenges lie ahead. "I think that the reported numbers represent a significant development," she says. "Of course, scale-up systems must be shown to be equally efficient in future work." The work is part of a Department of Energy clean-coal initiative launched in 2003 that aims to build, within ten years, a highly efficient, multi-megawatt, solid-oxide fuel-cell power plant paired with coal-gasification technology. The United States is thought to have about 250 years' worth of coal in the ground. But burning coal looms as a major factor in increasing global warming; indeed, coal releases more carbon dioxide for each unit of energy produced than any other fossil fuel does. In coal-gasification plants, the coal is heated and turned into a "syngas," a mixture of mainly carbon monoxide and hydrogen. This can then be combusted in a type of power plant called Integrated Gasification Combined Cycle. The GE technology would allow hydrogen to be pulled out of the syngas and sent through a solid-oxide fuel cell. |
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A Cool Fuel Cell
08/04/2008
Massachusetts Institute of Technology
Comments
MarkShapiro on 10/23/2006 at 3:14 PM
13
Better yet, if the reliable DC electric output could be used directly for electronic devices (such as for a computer server farm), you avoid all the costs and losses of converting to AC and back to DC.
eminentas on 10/23/2006 at 4:17 PM
2
This is the energy used from manufacturing the components going all the way up to having the system operating and producing some type of energy (electricity or heat basically).
It would be interesting to evaluate the amount of energy involved on producing a unit of SOFC, let’s say 1 kWe, and compare with other technologies.
I believe there is a huge amount of energy involved on preparing the wafers of ceramic electrodes and cocking them at high temperatures (usually above 1000°C).
A similar case occurs on making the silicon ingots for solar photovoltaic cells that at the end will be less than 15% efficient.
The good point for SOFC is the possibilities for heat recovery and co-generation from which an important amount of high quality heat can be recovered and utilized for space heating, process heat, process steam or moving an adsorption chiller for A/A.
On this way we could reach easily 75% up to 85% efficiencies. This is very good.
Another point is to include the efficiency for making the syngas from coal.
An alternative approach is the use of conventional heating oil (with very low sulfur content) directly on SOFC, without pre-reforming, since the infrastructure for using heating oil is already in place.
At the SOFC operating temperature it is possible to use this fuel.
Some Japanese,UK and American universities support this route on SOFC.
Based on this fuel, the deployment of residential and commercial SOFC would be easily enabled.
49% fuel cell efficiency is a very good figure and if we could place on top on this a heat recovery system even better.
TaffyDownUnder on 10/26/2006 at 8:06 PM
2
asdar on 11/01/2006 at 4:08 PM
64