Palladium-silver alloys reactor

Palladium and palladium-silver alloy membranes on porous alumina tubes were prepared by means of simultaneous and sequential electroless plating techniques [234], The membrane reactor was used for the direct formation of hydrogen peroxide by catalytic reaction of H2 and 02 at 293 K. The concentration of H202 increased with increases in the transmembrane partial pressure gradient of H2. A high concentration of H202 was obtained with a membrane that consisted of a palladium layer on the outer surface, porous alumina in the middle, and a palladium-silver alloy layer on the inside. 

W. H. Lin, Y. C. Liu and H. F. Chang, Elydrogen production from oxidative steam reforming of ethanol in a palladium-silver alloy composite membrane reactor, J. Chin. Inst. Chem. Eng., 2008, 39, 435-440. 

Much better catalysts now provide improved operation. Hydrogenation can be controlled by adding traces of carbon monoxide to the hydrogen. Adsorbed carbon monoxide modifies the relative adsorption of acetylene and ethylene on the palladium and minimizes ethylene loss. The catalyst itself can also be made more selective by alloying the palladium with a further metal such as copper or silver. This also affects pallacfium dispersion and the relative adsorption of acetylene and ethylene on the catalyst surface to improve selectivity. To minimize temperature rise catalyst suppliers recommend that one or more catalyst beds with intercoolers be used in each reactor, depending on the acetylene content of the C2 stream ... 

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