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 co ntaining two types of supported precious metal membranes: one is an electro less-plating palladium membrane, and the others are CVD palladium, platinum , and ruthenium membranes. A CVD platinum membrane having a H-2/N-2 separat ion factor as high as 280 gave an excellent performance comparable to the e lectroless-plating palladium membrane. The advantages of the CVD platinum m embrane versus the electroless-plating palladium membrane are lower metal l oading and lower cost as well as a lower tendency toward hydrogen embrittle ment, It is also shown in this study based on a computer simulation that co mpared with thermodynamic equilibrium, the non-palladium CVD membranes prod uced a high conversion of methane similar to an electroless-plating palladi um membrane only when showing high hydrogen permselectivity. The catalyst p acking in front of the membrane zone enhances the membrane reactor efficien cy. (C) 2000 Elsevier Science B.V. All rights reserved.