Deactivation of Hydroprocessing Catalysts:Thermochemistry of Coke Formation

摘要

The condensation of polyaromatic hydrocarbons (PAH) often is cited as a mechanism for coke-induced catalyst deactivation in hydroprocessing units.Such condensation reactions are inhibited by PAH saturation,which explains why high hydrogen partial pressure (ppH2) inhibits deactivation.This paper describes a simple system designed to model the competition between these two types of reactions:We wanted to use the dimerization of naphthalene for Equation 3,but our physical property database contained no information on C20 PAH.We didn't want to resort to estimates for C20 compounds,so instead we used o-xylene as a proxy;it is only allowed to condense with naphthalene to form chrysene.