Thermodynamic and experimental study of combined dry and steam reforming of methane on Ru/ ZrO 2-La 2O 3 catalyst at low temperature

Abstract

Analysis of the effect of adding small amounts of steam to the methane dry reforming feed on activity and products distribution was performed from thermodynamic equilibrium calculations of the system based on the Gibbs free energy minimization method. This analysis is supported by new insights from the direct experimental investigation of the influence of co-feeding with H 2O over a Ru/ZrO 2-La 2O 3 catalyst. Activity measurements were carried out in a fixed-bed reactor but using the operating conditions applicable in a Pd membrane reactor, that is, at maximum reaction temperature below 550 °C. Experimental results were in good agreement with thermodynamics predictions. It was observed that the addition of H 2O into the dry reforming feed strongly affects activity and products distribution. The co-feeding of steam resulted in increasing methane conversion and hydrogen yield but decreasing carbon dioxide conversion and carbon monoxide yield. At a given temperature, syngas composition (H 2/CO ratio) can be tuned by changing the amount of H 2O co-fed. Interestingly the stability of the Ru/ZrO 2-La 2O 3 catalyst was improved by adding steam to the dry reforming reactant mixtures.