Solid Oxide Fuel Cells - The Non-Hydrogen solution

[bisi77]

Hello everybody,

I did a PhD at Paul Scherrer Institut and the Swiss Federal Institute of Technology in Zurich in the field of Fuel Cells and Biomass Gasification. The result of my work was the world 1st continuous operation with pure wood gas of a full-scale residential Solid Oxide Fuel Cell residential combined heat and power system. The project has gone to the next level and PSI is in the
process of designing a pilot plant.
Thus, I guess one could say that hydrogen is not absplutely necessary for a clean energy future involving fuel cells. I'd be happy about any comments and thoughts of you on this rather provoking statement. If you want to know more about fuel cells in general and their application with gasification derived fuel gases, feel free to download my thesis:


Electricity from wood through the combination of gasification and solid
oxide fuel cells:

http://e-collection.ethbib.ethz.ch/e...h-41553-02.pdf

(Sometimes the link to the pdf doesn’t seem to work, try right click "save
as" then)

Cheers

[myocardia]

Hi, welcome to Nature2Energy. I've been reading your thesis, and at 352 pages it's going to take awhile to read, but so far it has been very interesting. Can you tell us mere mortals with no degree in chemistry any more about the process of wood gasification? This is the first time I've heard that term, and I can see how that might be an enormous benefit, since wood is as much a stored solar energy as oil happens to be.

[bisi77]

Hi myocardia. I m no chemist either but mechanical engineer anyways, wood gasification is a pretty old technology and first "played with" around the 19th century. The peak of thetechnology was reached during the 2 world wars, where the Germans had to find ways to run their cars without gasoline. During these times, the most famous gasifier (the Imbert gasifier) was developed. After the wars, the technology was kind of forgotten as nobody felt a real need for it given the abundance of oil. Only recently, say some 10 years ago, academia and industry rediscovered this technology to turn solid carboneous fuels into combustible gas.
The chemistry behind the gasification of solid wood is described in detail in my thesis, but if you want a really short discription, here we go: Gasifying wood is like burning it except that you don't add enough air for complete combustion. For instance, every carbon atom in the wood requires one oxygen molecule to be converted to carbon dioxide, the final product of carbon combustion. If you only add one oxygen molecule per two carbon atoms, you ll end up with carbon monoxide. This is a combustible gas that can be used as fuel in fuel cells..But be carefull. Only high-temperature fuel cells will be happy with that fuel gas. PEM fuel cells, the ones usually employed in cars, will die from this stuff..
If you want to have a hands-on idea about what gasification is, lite up a match and observe where the flame burns. You ll see that the wood itself doesnt burn but the flame hovers some millimeter above the wood. What's happening is that the flame "gasifies" the wood and is fed by the produced gas. In a gasifier, you basically take the flame away..easy as that