On an industrial scale, the efficiency of heterogeneous catalysis is commonly subject to diffusive transport limitations. The binary friction model (BFM) combines Maxwell-Stefan-type diffusion, pore effects and viscous contributions for multicomponent reaction mixtures. A variety of catalyst shapes have been developed over the years to overcome transport problems. However, rigorous modeling of multicomponent diffusion-reaction problems in 3D geometries remains an ongoing challenge. We successfully applied the BFM to nine shapes, all varying in size and catalyst loading. The volume-to-surface ratio and the curvature of the bodies were found to be the characteristic features of the pellets, describing the reaction-diffusion interplay. With this, the 3D shape can be adequately approximated with straightforward 1D strategies. Finally, a comparison to Fickian diffusion models highlights the similarities and discrepancies to the Maxwell-Stefan concept of the BFM. These findings can contribute to an integral description of 3D reaction-diffusion problems in homogeneously distributed, mesoporous catalysts.
