A long‐term multiscale model for acetylene hydrochlorination: Coupling intra‐particle evolution with reactor performance

Abstract

The long‐term economic viability of mercury‐free catalysts for acetylene hydrochlorination requires precise thermal management to prevent the deactivation of sensitive active sites. We developed a validated, spatiotemporal multiscale model that integrates intrinsic kinetics with intra‐particle transfer and reactor‐scale transport, successfully predicting catalytic performance and deactivation trends from laboratory to pilot scale. Its modular architecture was designed to incorporate detailed sub‐models, enabling explicit resolution of non‐spherical catalyst geometries and intra‐particle non‐uniform deactivation of active sites. The analysis shows that hotspot intensity arises mainly from a mismatch between internally mass‐transfer‐limited heat generation and externally heat‐transfer‐limited heat dissipation, which ultimately controls catalyst stability. Furthermore, time‐advancement simulations uncover an intra‐particle activity stratification, demonstrating that spatially non‐uniform activity loss buffers downstream hotspot migration and ultimately extends overall catalyst lifetime. This work provides a powerful, particle‐centric modeling strategy for the design and long‐term optimization of fixed‐bed reactors for highly exothermic processes.