Multi-scale Simulations in a Catalytic Reactor Considering Three-dimensional Pellet Geometry

Catalytic reactors that convert carbon dioxide into methanol are one of the key technologies in carbon recycling. Various numerical simulations have been conducted to study catalytic reactors, including multi-step chemical reactions, flow, reaction heat, heat transfer, and diffusion. However, in most cases, the microstructures of the catalyst bed are treated as a homogeneous body, in which permeability, diffusion coefficient, and thermal conductivity are estimated by simplified estimation formula, making it difficult to evaluate the effects of the differences in pellet shapes. In this study, we developed a macroscopic homogenization model combined with a three-dimensional microstructure in the catalyst bed in order to predict complex phenomena in the reactor. The model validation was also performed with the actual experiments of catalytic reactions. Furthermore, the effects of different pellet shapes on the temperature, flow field, and reaction field in the reactor were compared.