Optimizing catalyst pore network structure in the presence of deactivation by coking

Designing the pore network structure is an effective approach to improve the performance of industrial catalyst particles, although it receives less attention than designing catalytic surfaces or active sites. This work presents a first example of the optimization of catalyst pore network structures in the presence of deactivation by coke formation, using a three-dimensional pore network model. Propane dehydrogenation in a Pt-Sn/Al2O3 catalyst particle is taken as the model reaction system. Catalyst particles with unimodal and bimodal pore-size distributions are investigated, both being commonly used in industry. The porosity, connectivity, pore size, and their spatial distributions are optimized under two separate assumptions: constant intrinsic activity per unit catalyst weight and constant intrinsic activity per unit internal surface area. The optimized catalyst shows up to 14-fold improvement in the time-averaged propene formation rate, when compared to a benchmark catalyst. This significant improvement is primarily because of reductions in diffusion resistance and pore blockage.