Kinetic of methane steam reforming reaction over nickel- and rhodium-based catalysts

Kinetics of methane steam reforming over a commercial nickel-based catalyst and over an innovative rhodium-perovskite catalyst of formula BaRhxZr(1-x)O3 was studied at atmospheric pressure and in the temperature range 723-1023 K. Extensive experimental runs were firstly carried out in a micro-reactor, with the catalysts in powder form, to evaluate their performances in steam methane reforming process. The behaviour of rhodium-perovskite catalyst was analyzed as function of steam-to-methane ratio and temperature, comparing the obtained performances of this catalyst with that showed by the commercial nickel-based one. Rhodium-perovskite catalyst shows higher activity for steam methane reforming reaching methane conversions higher than those obtained with the nickel-based catalyst and closer to the thermodynamic equilibrium value. Based on a detailed review of the kinetic models proposed for steam reforming, the experimental data were fitted using a simple kinetic model where the conversion of methane is proportional only to the methane partial pressure. Good agreement was obtained between the experimental data and the kinetic model prediction. (C) 2010 Elsevier B.V. All rights reserved.