Pd−Ag−Au−Ni Membrane Reactor for Methoxymethane Steam Reforming

The permeability of hydrogen through a Pd-Ag-Au-Ni membrane was determined at temperatures between (473 and 573) K at a hydrogen pressure of between (1.0 and 4.0) 10 5 Pa. Methoxymethane steam reforming (C 2 H 6 O + 3H 2 O(g) = 6H 2 + 2CO 2 ) with a Pd-Ag-Au-Ni membrane reactor is used to produce hydrogen in proton exchange membrane fuel cells (PEMFCs). This process uses a bifunctional catalyst of (CuO―ZnO―Al 2 O 3 ―ZrO 2 + ZSM-5) in mass fraction ratio of each component of 50 %. The determined methoxymethane conversion, hydrogen yield, and hydrogen recovery flow in a reactor were compared to those in a fixed bed reactor. The operating parameters were pressures of (1.0 to 4.0)•10 5 Pa, temperatures of (473 to 573) K, and input mass fraction ratios of H 2 O-to-C 2 H 6 O of (3 to 7) at velocities of between (1180 and 9000) cm 3 •g ―1 •h ―1 . The conversion of C 2 H 6 O was higher in the membrane reactor due to the countercurrent removal of hydrogen. In the membrane reactor, the thermal energy needed for the endothermic steam reforming can be provided by the combustion of the exit stream from the membrane reactor. The enthalpy for the reactions indicated coupling, and both reforming and oxidation reactions gave a energy recovery of about 85 %.