Metallic membranes methanol steam reformer

A commercial nickel catalyst was used for methane steam reforming performed at a 500 °C reaction temperature, a S/C ratio of 3.0 and atmospheric pressure, while the permeate side was evacuated. The performance of the vapour deposited platinum membrane was similar to the plated dense palladium membrane. In the permeate of the deposited ruthenium and palladium membranes, small amounts of carbon oxides and also methane were observed. While it was expected that all these species had passed through the membranes by diffusion, in addition some methane was converted into carbon dioxide over the noble metals of the membranes. Kikuchi et al. demonstrated by simulations that conversion and hydrogen permeation in a membrane reactor is higher, where the first portion of the catalyst bed is not coupled to the membrane. Such an arrangement as shown in Figure 7.16 would clearly save expensive membrane surface area. Experimental work by Itoh et al. performed for methanol steam reforming [521] confirmed the assumptions of Kikuchi et al. 

Metal foam (see, for example. Figure 3.5) has already been discussed in the context of heat exchangers. Micro-reactors, highly relevant to the subject of small fuel cells, have also been introduced in earlier chapters. The construction of metal foam based methanol steam micro-reformers to generate hydrogen for polymer electrolyte membrane fuel cells (PEMFCs) has been reported and in Guangzhou, Chinese researchers have looked at laminated micro-reactors in which copper-based catalysts have been supported by metal foams (see Figure 11.11 Yu et al., 2007). 

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