Hydrogen production from methane by steam reforming in a periodically operated two-layer catalytic reactor

Almost CO-free hydrogen gas, which could be directly used as a feed for a PEM fuel cell, can be produced by a novel steam reforming process of methane in a fixed bed reactor which contains two different catalysts layers which go through a periodic reduction/re-oxidation cycle. During the reduction phase, water-free methane is converted at the first layer (Pt-Ce0.5Zr0.5O2) into a mixture of CO and H-2 by partial oxidation. This mixture is fed directly to a second layer of Fe2O3-Ce0.5Zr0.5O2 where the products of the methane partial oxidation reduce the iron-containing catalyst whereby giving CO2 and H2O. During the re-oxidation phase of the cycle, the two-layer reactor is fed with pure steam which is converted into a CO-free hydrogen gas whereby leading to the re-oxidation of the catalytic materials in both layers so that that they can be reused in the next redox cycle. The present study reports the preparation and characterization of suitable catalytic materials, related activity tests and kinetic studies which demonstrate the feasibility of the proposed process concept. (c) 2005 Elsevier B.V. All rights reserved.