Kinetic investigations on methanol steam reforming on PdZn catalysts in microchannel reactors and model transfer into the pressure gap region

Abstract

In the present study, a microchannel reactor was used in an integral mode of reactor operation to investigate parameter influences on the steam reforming of methanol on PdZn catalysts prepared by washcoating the microchannels with ZnO nanoparticles. Different models derived from significant concentration parameters were evaluated concerning their suitability to describe the kinetics of the methanol reforming reaction in the examined parameter range. Water gas shift reaction was found to be negligible in the reaction network. Methanol decomposition, even though it was influenced by the reactor material, was neglected for the modelling since CO was present only at a minor extent at the reactor outlet. Superior isothermal behaviour of the microchannel reactor is supposed to be responsible for good correlations of the derived models with experimental results. One of the models, the “global model”, was transferred to results from experiments in the pressure gap region obtained in a similar microchannel reactor suitable for low-pressure application. Although this was a model extrapolation, model and experiment were in good accordance for a wide range of absolute and methanol partial pressures, molar ratios of water to methanol and temperatures.