Influence of the kinetic sub-model on the performance of a comprehensive model of a micro-scale catalytic reactor

Abstract

Abstract This work investigated a micro-scale catalytic plate reactor designed for thermal coupling of an exothermic reaction (combustion) to endothermic reforming reactions. The system was studied through both experiments and modelling. A 3D model, previously developed by the authors, was employed and adapted to simulate the real reactor geometry. The aim of the work was to study the influence of different kinetic sub-models for the reforming reactions on the model results. Multi-component mass transport was modelled using a Fick-like law. Operating conditions utilized in the experiments and for the modelling were those typical of reforming reactions. The kinetics sub-models of the methane reforming and combustion reactions were taken from the literature. In particular, for the combustion process a power-law kinetic expression was used with a linear dependence on methane concentration and zero dependence on oxygen concentration. Instead, for the reforming reactions two different kinetics, suggested, respectively, by Xu and Froment and by Hou and Hughes, were employed. The comparison between model results and experimental findings was performed to discriminate which of the two reforming kinetics was more suitable to describe the experiments. It was found that when using the reforming proposed by kinetics Hou and Hughes was employed, the agreement between model results and experiments was elevated while it resulted poor when the other kinetic sub-model was used. An analysis of the features and of the origins of the two sub-models was performed and the comparisons with the characteristics of our experiments was carried out in order to find the reasons for the different agreement.