Modeling of the catalytic cracking: Catalyst deactivation by coke and heavy metals

This paper proposes a model of the cracking process considering the catalyst deactivation by Ni, V and coke. The developed model is sensitive to the feedstock composition and describes the kinetics of cracking reactions leading to coke formation, the structural and selective properties of the catalyst. It also reflects the main technological parameters. The forecast calculations showed that when the resins and Ni contents in the feedstock increase by 4.2 wt% and 0.6 ppm, the coke contents on the catalyst increase by 0.75 and 0.32 wt% wt. under the other equal conditions. The catalyst activity decreases by 4.4% relative to initial value along with increasing the V content in the feedstock by 1.9 ppm due to its dealumination. If the Ni with V co-presence in the catalytic cracking feedstock and the Ni content increases by 0.6 ppm, the V destructive effect reduces by 1.2% due to reaction of Ni with the vanadic acid, also Ni on the catalyst increases the catalyst dehydrogenation activity. According to the calculations performed, the yield of the gasoline fraction changes by 4.43 wt%, depending on the feedstock composition (CSH/CAH = 1.6–1.8 units), other things being equal.