2020 Volume 53 Issue 8 Pages 389-396
Micro-partition (MP; supplied by Nano Cube Japan Co., Ltd.) which is commercially available as a heat sink for precision electronic parts (and generally not as a catalyst support), was adopted as a structured catalyst support. The MP was made from aluminum; it was converted into an alumite catalyst as structured catalyst and applied for a gas–solid catalytic reaction. The MP has micro fins and holes; therefore, the reactivity was expected to improve because the reactant fluid would be disarranged. In this research, we linked the disarrangement of the fluid with the reactivity, analyzed the flow state of the reactants in detail, and evaluated its effect on the reactivity. Experiments and a three-dimensional simulation were carried out to investigate the relationship between the structure and reactivity. Steam reforming of methanol was adopted as the model reaction. When the structured catalyst was used, the conversion increased by 80% at 553 K compared with that of a non-characteristic structured catalyst plate, and it was implied that the improvement in reactivity was better at lower temperature. The characteristic structure of the MP, not only the fins but also the holes significantly improved the reactivity. An analysis of the reaction rate showed that the contact frequency between the reactants and the catalyst increased. Furthermore, an index to evaluate the promotion of mass transfer was introduced when analyzing the mass transfer around the catalyst using dynamics simulation. The simulation showed that the structure promoted the mass transfer by convection, and a similar trend as the experiments was observed; the effect of the structured catalyst was larger at lower temperature condition. The factor of the reactivity improvement by the structured catalyst became clear from the results of the experiments and simulation.