Simulation of catalytic reactions in open-cell foam structures

TL;DR

This paper presents a particle-based simulation method for heterogeneous catalysis in open-cell foam structures, validated against experimental data, revealing optimal porosity for efficient flow and conversion.

Contribution

The paper introduces a novel simulation technique combining iSRD and CSG for modeling catalytic reactions in foam structures, validated with experimental results.

Findings

Catalyst density can be reduced without losing efficiency.

Large porosity structures optimize flow and conversion.

Two flow regimes identified around Reynolds number 10.

Abstract

We describe a technique for particle-based simulations of heterogeneous catalysis in open-cell foam structures, which is based on isotropic Stochastic Rotation Dynamics (iSRD) together with Constructive Solid Geometry (CSG). The approach is validated by means of experimental results for the low temperature water-gas shift reaction in an open-cell foam structure modeled as inverse sphere packing. Considering the relation between Sherwood and Reynolds number, we find two distinct regimes meeting approximately at the strut size Reynolds number 10. For typical parameters from the literature, we find that the catalyst density in the washcoat can be reduced considerably without a notable loss of conversion efficiency. We vary the porosity to determine optimum open-cell foam structures, which combine low flow resistance with high conversion efficiency and find large porosity values to be favorable not only in the mass transfer limited regime but also in the intermediate regime.