Quantifying the impact of intraparticle convection within fixed beds formed by catalytic particles with low macro-porosities

Abstract

Computational fluid dynamics (CFD) modeling plays a pivotal
role in optimizing fixed bed catalytic chemical reactors to enhance performance
but must accurately capture the various length- and time-scales that underpin
the complex particle−fluid interactions. Within catalytic particles, a range of
pore sizes exist, with micro-pore scales enhancing the active surface area for
increased reactivity and macro-pore scales enhancing intraparticle heat and
mass transfer through intraparticle convection. Existing particle-resolved CFD
models primarily approach such dual-scale particles with low intraparticle
macro-porosities as purely solid. Consequently, intraparticle phenomena
associated with intraparticle convection are neglected, and their impact in
the full bed scale is not understood. This study presents a porous particle CFD
model, whereby individual particles are defined through two distinct porosity terms, a macro-porosity term responsible for the
particle’s hydrodynamic profile and a micro-porosity term responsible for diffusion and reaction. By comparing the flow profiles
through full beds formed by porous and solid particles, the impact of intraparticle convection on mass and heat transfer, as well as on
diffusion and reaction, was investigated.

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Identifiers

ORCID for Matthew E. Potter: orcid.org/0000-0001-9849-3306

ORCID for Robert Raja: orcid.org/0000-0002-4161-7053

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