Kinetics and mechanism of attrition of several fcc catalysts

Catalyst attrition resistance is extremely important in the operation of fluid catalytic cracking (FCC) units because of potential problems with loss of catalyst and contamination of the subsequent products. Attrition behavior of several FCC catalysts and catalyst additives in oil refineries was investigated through lab-scale jet-cup test. The influences of ambient hydrodynamic parameters and material characteristic properties on particle attrition mechanism were mainly explored and clarified. The experimental results indicate that the particle size distribution has great influence on the attrition behavior of the catalysts tested, and a mixed attrition mechanism consisting of abrasion and fragmentation is identified for all the catalysts in terms of attrition loss rate evaluation, after-attrition morphology characterization and particle size distribution analysis. It is shown that the attrition of particles was found to evolute following Gwyn's kinetic model and the difference of attrition mechanism of various particles can be categorized with parameters of the Gwyn equation.