Deactivation and regeneration of Claus catalyst particles unraveled by pore network model

Abstract

A pore network model is proposed to study the deactivation of Claus catalysts caused by sulfur condensation, as well as the corresponding regeneration. This model allows to describe the coupled reaction, diffusion, and sulfur condensation from a single pore to a catalyst particle. The results show that the deactivation branch of apparent activities is well above the regeneration branch in the temperature and pressure ranges where capillary condensation of sulfur occurs. This phenomenon of multiple steady states can be attributed to the inconsistent contents of liquid sulfur in the catalyst particle when changing temperature and pressure in different directions. The catalyst particle shape and pore network structure directly influence diffusion resistance, internal surface area for reaction, and sulfur condensation, and subsequently pass these influences on to the apparent activity. This work should provide a proper model and some useful guidelines for the design of catalyst particles for the Claus reaction.