110th Anniversary: Commentary: CFD as a Modeling Tool for Fixed Bed Reactors

Computational fluid dynamics (CFD) is a valuable tool in the modeling of fixed bed reactors. In particular, resolved-particle CFD in which a bed of particles is simulated directly, without invoking a porous media representation, is being used to probe reaction systems and understand the complexities of reactions in heterogeneous systems. Some reviews are now available, and the number of publications is growing. In this contribution, a broad perspective is attempted on what are some of the key issues, what problems should be solved for further progress, and what new techniques might be applied. Topics discussed are the numerical generation and meshing and simulation of beds of complex particle shapes, coupling microkinetics with resolved-particle CFD, validation with in situ experimental methods, and some suggestions for the possible role of visualization techniques and machine learning in the interpretation of the large amounts of information generated by CFD.