Fuel processors

Heat rejection is only one aspect of thermal management. Thermal integration is vital for optimizing fuel cell system efficiency, cost, volume and weight. Other critical tasks, depending on the fuel cell, are water recovery (from fuel cell stack to fuel processor) and freeze-thaw management. 

Fuel cells can run on fuels other than hydrogen. In the direct methanol fuel cell (DMFC), a dilute methanol solution ( 3%) is fed directly into the anode, and a multistep process causes the liberation of protons and electrons together with conversion to water and carbon dioxide. Because no fuel processor is required, the system is conceptually vei"y attractive. However, the multistep process is understandably less rapid than the simpler hydrogen reaction, and this causes the direct methanol fuel cell stack to produce less power and to need more catalyst. 

Development of Highly Compaet PROX System for PEMFC Fuel Processor... 

Computational study on the micro-channel fuel processors... 

Ereeman, H. D., Marco, J. L., Roberts, G. L., VanderWiel, D. P., A compact steam reforming reactor for use in an automotive fuel processor, in Proceedings of the 4th International Conference on Microreaction Technology, IMRET 4, pp. 358-363 (5-9 March 2000), AIChE Topical Conf. Proc., Atlanta, USA. 

Phelps, M., Guzman, C., Sub-watt power using an integrated fuel processor and fuel cell, in Matlosz, M., Ehreeld,... 

Qi, A., Peppley, B., Karan, K. (2007) Integrated Fuel Processors for Fuel CeU Application A Review. Fuel Processing Technology, 88, 3-22. 

NASA conducted studies on the development of the catalysts for methane decomposition process for space life-support systems [94], A special catalytic reactor with a rotating magnetic field to support Co catalyst at 850°C was designed. In the 1970s, a U.S. Army researcher M. Callahan [95] developed a fuel processor to catalytically convert different hydrocarbon fuels to hydrogen, which was used to feed a 1.5 kW FC. He screened a number of metals for the catalytic activity in the methane decomposition reaction including Ni, Co, Fe, Pt, and Cr. Alumina-supported Ni catalyst was selected as the most suitable for the process. The following rate equation for methane decomposition was reported ... 

InnovaTek, InnovaGen Fuel Processor, available at http //www.tekkie.com/docs/InnovaGen.pdf (accessed July 2007). 

Carbon Deposition. The processing of hydrocarbons always has the potential to form coke (soot). If the fuel processor is not properly designed or operated, coking is likely to occur. Carbon deposition not only represents a loss of carbon for the reaction but more importantly also results in deactivation of catalysts in the processor and the fuel cell, due to deposition at the active sites. 

Gary Jacobs and Burt Davis (University of Kentucky) review catalysts used for low-temperature water gas shift, one of the key steps in fuel processors designed to convert liquid fuels into hydrogen-rich gas streams for fuel cells. These catalysts must closely approach the favorable equilibrium associated with low temperatures, but be active enough to minimize reactor volume. The authors discuss both heterogeneous and homogeneous catalysts for this reaction, with the latter including bases and metal carbonyls. 

In the 1990s and beyond 2000, there has been an explosion of interest in metal/ partially reducible oxide catalysts for low temperature water-gas shift, mainly directed at the production/purification of hydrogen in a fuel processor for fuel cell applications. 

C) Metal/Ti02 catalysts. References479 501 cover work on metal/Ti02 catalysts from 1980, which focused primarily on photo-assisted water-gas shift, to the present, which is currently aimed at utilizing the catalyst for hydrogen cleanup steps in fuel processors for fuel cell applications. 

However, in developing new fuel processors for hydrogen production to feed low-temperature fuel cells, one should bear in mind the following limitations of the conventional processes [29] ... 

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