Computational Fluid Dynamics Modeling of Macro-Meso Porous Monoliths for Continous Catalysis

Abstract

In this study, a 2D axisymmetric homogenized monolith geometry was utilized to develop a CFD model, which was then applied to investigate the heterogeneous catalyzed Knoevenagel condensation reaction. The CFD model encompasses convective fluid flow in the macro pores, species diffusion, and reaction kinetics in the meso pores of the monolith. The model's accuracy was affirmed through successful validation against previously available experimental data in the literature for the Knoevenagel condensation reaction. Subsequently, the model was employed to examine the influence of key parameters, such as meso and macroporosity, on flow and diffusion. Moreover, reaction parameters, including temperature and multiscale reactor size, were explored, ranging from the pore level to the reactor length. To analyze flow patterns and concentration profiles at the macro pore level, porescale simulations were conducted through image processing and CFD modeling of 25x25 µm Scanning Electron Microscopy (SEM) images of the porous monoliths. These simulations yielded an in-depth comprehension of pore flow and concentration behaviors at the macro-meso level, offering valuable insights for optimizing pores in hierarchical structures.