Vanadium-Zeolite Interactions in Fluidized Cracking Catalysts

Abstract

Metal levels on equilibrium fluidized cracking catalysts (FCC) have been increasing through the years (Fig. 1), indicating that the study of the physicochemical properties of metal resistant FCC has remained an important topic to refiners [1]. After the crude oil price collapse of 1986, Ni levels on equilibrium FCC have remained fairly constant whereas V levels have somewhat decreased owing to the greater availability (and lower cost) of high-quality crudes; Fig. 2. At the metals levels shown in Fig. 1, Ni and V catalyze the undesirable cracking of hydrocarbons in the gasoline boiling range, thus increasing coke and hydrogen yields. Vanadium-induced activity losses can be easily circumvented with the proper catalyst management and increased makeup rates. However, should refiners in the future undertake the cracking of residual oils or crack certain readily available crudes from Venezuela and Mexico, metals (especially V) will probably increase well above the levels shown in Fig. 1 and novel FCC will have to be found to negate the severe effects of V on cracking activity.