CATALYTIC CRACKING WITH FCCT LOADED WITH TIN METAL TRAPS - ADSORPTIONCONSTANTS FOR GAS OIL, GASOLINE, AND LIGHT GASES

Catalysts, so-called FCCT (catalysts for fluid catalytic cracking (FCC ) with ''in situ metal traps''), were developed to achieve high disper sion of passivators. These FCCTs were extensively tested and demonstra ted experimentally. The catalyst, steamed to achieve equilibrium condi tions, was artificially impregnated with a tin compound (0-3750 ppm) a nd with nickel and vanadium naphthenates. Experimental runs were perfo rmed ina microcatalytic fixed bed reactor using different carrier gas flows (120-150 std mL/min) and different temperatures (510-550 degrees C). The unsteady state pulse technique, gas oil pulses reacting with FCC catalyst, was used to study the effects of metal traps in a FCC ca talyst contaminated with 3000 ppm of Ni and 4500 ppm of V. The four-lu mp model featuring gas oil, gasoline, light gases, and coke was used t o evaluate the kinetic constants. The equations developed for the four -lump model were also used to evaluate the adsorption constants for ga s oil, gasoline, and light gases.;These parameters are of special impo rtance for the simulation of industrial scale FCC risers. Experimental results demonstrated that gas oil conversion recovered significantly with FCCTs. It was also proven that the effects of the addition of the in situ metal traps were beneficial on gasoline yield, gasoline selec tivity, and research octane number. A major contribution of the in sit u metal traps was an important reduction in coke yield. Consistent wit h this result a reduced catalyst deactivation was observed with FCCTs.