Fuelling Fuel Cells

Another commonly used way of producing hydrogen is to use electricity to eleclrolyse water - the reverse of a fuel cell. Since the purpose of a fuel cell is to produce electricity, this may at first seem perverse. However, in many cases it is in fact a very convenient and efficient way of providing hydrogen for mobile fuel cells. Electrolysers are briefly discussed in Section 8.7. 

Fuel Cell Systems Explained, Second Edition James Lanninie and Andrew Dicks 2003 John Wiley Sons, Ltd ISBN 0-470-84857-X 

A promising way of producing hydrogen that is not yet commercially used, but may well be soon, is using biological methods to break down the fuel - fossil or bio. Some of these methods are based on enzymes, others on bacteria, and still others use light. These methods, and their prospects, are outlined in Section 8.8. 

These hydrogen-carrier compounds can be made to give up their hydrogen much more easily than fossil fuels and can be used in mobile systems. The most important of these compounds, and the ways they could be used, are explained in Section 8.10. 

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According to Kawatsu, from Toyota [30], a ruthenium catalyst was used in the fuel processor of the Toyota methanol-fuelled fuel cell vehicle (see Section 9.1). It was claimed to show less reverse water-gas shift and higher selectivity compared with a platinum catalyst. Giroux et al. also proposed the application of ruthenium- or copper-based catalysts, especially for a second stage preferential oxidation reactor [57]. Farrauto et al. even mention the possibility of three preferential oxidation stages [107], which seems too complicated for a practical application. 

Toyota developed a methanol-fuelled fuel cell vehicle that was presented shortly after the NECAR 3, in September 1997, which is shown in Figure 9.11. It had a range of 500 km and a maximum power of 50 kW. It worked with a methanol steam... 

Figure 9.11 Methanol-fuelled fuel cell electric vehicle (FCEV) developed by Toyota [30. ...

Meyer et al. also described the full range of hydrocarbon fuelled fuel cell systems that International Fuel Cells, LLC had developed by the year 2000 [627]. The fuels ranged from methane to heavy hydrocarbons and the system size from 500 W to 11 MW. The fuel cell technology, which was suppUed with hydrogen from the fuel processors, were reported to cover alkaline, proton exchange, molten carbonate and phosphoric acid fuel cells. However, no details were provided concerning the specific applications or performance of these systems. 

The aim of this chapter is to provide an overview of the issues involved in fuelling fuel cells, starting from the thermodynamics of reactions at the anode, through fuel processing and alternative fuels, and concluding with a look at the deleterious effects of impurities and the fuels themselves on performance. 

DaimlerChrysler developed a methanol processor for the NeCar 3 experimental vehicle. This was demonstrated in September 1997 as the world s first methanol-fuelled fuel cell car. It was used in conjunction with a Ballard 50-kW fuel cell stack. Characteristics of... 

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