CFD modeling of mass transfer in Gas-Liquid-Solid catalytic reactors

This work investigates Gas-Liquid-Solid mass transfer coupled to heterogeneous catalytic reaction using Computational Fluid Dynamics (CFD). The numerical model is based on the Volume-of-Fluid (VOF) approach, coupled with a convection-diffusion equation for mass transfer resolution. First, the numerical method is validated on a falling liquid film over a semi-infinite planar surface. Then, a micro-structured reactor with alpha-methylstyrene hydrogenation is studied. A good agreement is found between experimental data of Tourvieille et al. (2013) and simulation results. Afterwards, a vertical spherical beads string is investigated. Convective transport by transversal velocities is identified as an important contributor to the overall Gas-Liquid-Solid mass transfer. While the film model is applicable in pure diffusion regimes, the resistances-in-series model is not relevant and over-estimates the real mass transfer by nearly 30% when mass transfer occurs in liquid film flow without bulk. The present work shows how CFD can be an effective tool for predicting hydrodynamic and catalyst geometry effect on mass transfer in Gas-Liquid-Solid reactors. (C) 2020 Elsevier Ltd. All rights reserved.