(440c) Numerical Investigation of Heat Transfer in Fixed-Bed Reactors Filled with Complex Particle Shapes Using CFD

Catalytic fixed-bed reactors with a low tube-to-particle diameter ratio are widely used in the chemical and process industry. They are characterized by a heterogenous packing morphology that lead to a strong interplay between local flow effects and the heat and mass transfer within the system. For that reason, simplified pseudo-homogenous models lead to an erroneous numerical description of that reactor type which is why more sophisticated numerical methods are needed.

Particle-resolved computational fluid dynamics (CFD) is a first-principle modeling approach that has been proven to be a reliable and predictive tool to analyze the flow, temperature and species field within fixed-beds in a spatially resolved manner as recently reviewed by Jurtz et al. This allows the method to be used as a design tool for new particle shapes to optimize the trade-off between a high active catalytic surface, a low pressure drop and a good heat transfer characteristic.

Within the scope of this presentation a fully automated workflow for the simulation of fluid flow and heat transfer in fixed-beds filled with cylindrical particles, Raschig rings and multi-hole cylinders will be presented. The different particle shapes will be compared regarding their thermal performance and advanced post-processing methods will be used to understand the complex interplay between particle orientation, convective heat transfer within the inner particle voids and the overall thermal performance. It will be shown how effective transport parameters can be extracted from the simulation results that afterwards can be used in simplified numerical models.

Literature
Jurtz, N., Kraume, M. and Wehinger, G. (2018). Advances in fixed-bed reactor modeling using particle-resolved computational fluid dynamics (CFD). Reviews in Chemical Engineering. Published: 2018/02/02. Available at: https://doi.org/10.1515/revce-2017-0059 [Epub ahead of print]