A MATHEMATICAL MODEL FOR THE CATALYST DEACTIVATION IN A COMMERCIAL RESIDUE HYDRODESULFURIZATION REACTOR SYSTEM

Abstract

A mathematical model that describes catalyst deactivation in a commercial Residue Hydrodesulfurization (RDS) system is proposed. In this model, coking, metal deposition and the decrease of effective diffusivities are all considered, so that it can predict the dynamics of catalyst activity during a long run of an RDS system. The RDS system under consideration here is a complex trickle bed reactor system with four adiabatic reactors in series, between which the oil is quenched by hydrogen to prevent the catalysts in the next reactor from being damaged by high temperature. This article shows that by incorporating a catalyst deactivation model into the overall reactor system model, the predicted catalyst aging curve assumes the “S” shape, characteristic of real RDS system. The model prediction are compared with data from an operating refinery and the agreement is pleasing. KEYWORDS Residue Hydrodesulfurization(RDS) Apparent activity Catalyst deactivation curve Pore radius.