Steam reforming of methane, ethane, propane, butane, and natural gas over a rhodium-based catalyst

Steam reforming of methane, ethane, propane, butane, and a sulfur-free natural gas is studied over a rhodium-based monolithic honeycomb catalyst. The product distribution is analyzed as function of temperature (250-900 degrees C) and steam-to-carbon ratio (2.2-4) for two honeycomb channel densities (600 and 900 cpsi) and an uncoated monolith by gas chromatography and mass spectroscopy. The reactive flow in the single monolith channel is modeled by a two-dimensional flow field description coupled with detailed reaction mechanisms modeling surface and gas-phase kinetics. Ethane, propane, and butane are converted at much lower temperature than methane, also in natural gas mixtures. An impact of the presence of the higher hydrocarbons on methane conversion in steam reforming of natural gas is found. Steam reforming in the pure gas phase occurs only above 600 degrees C and the product spectrum differs from that of catalytic conversion. (C) 2009 Elsevier B.V. All rights reserved.