Steam reforming of methane in membrane reactors: comparison of electroless-plating and CVD membranes and catalyst packing modes

Steam reforming of methane was studied at 773 K using a membrane reactor containing two types of supported precious metal membranes: one is an electroless-plating palladium membrane, and the others are CVD palladium, platinum, and ruthenium membranes. A CVD platinum membrane having a H-2/N-2 separation factor as high as 280 gave an excellent performance comparable to the electroless-plating palladium membrane. The advantages of the CVD platinum membrane versus the electroless-plating palladium membrane are lower metal loading and lower cost as well as a lower tendency toward hydrogen embrittlement, It is also shown in this study based on a computer simulation that compared with thermodynamic equilibrium, the non-palladium CVD membranes produced a high conversion of methane similar to an electroless-plating palladium membrane only when showing high hydrogen permselectivity. The catalyst packing in front of the membrane zone enhances the membrane reactor efficiency. (C) 2000 Elsevier Science B.V. All rights reserved.