Nickel Passivation on Cracking Catalysts

Experiments on passivation of 1000-5000 ppm nickel on commercial zeolite-containing cracking catalysts were performed. The optimum passivator/nickel ratios for the catalysts containing up to 5000 ppm nickel were determined. The catalysts after the deactivation with nickel and its passivation were studied by such methods as temperature-programmed reduction with hydrogen, temperature-programmed ammonia desorption, X-ray diffraction analysis, and low-temperature nitrogen adsorption-desorption. The boron-containing passivator binds nickel into a difficultly reducible form, thus considerably reducing its dehydrogenating activity. The effect of deactivation of catalysts with nickel on their activity in the cracking of hydrotreated vacuum gasoil was demonstrated. The passivation of nickel in an amount of up to 5000 ppm with boron-containing compounds partially restores the activity of the commercial zeolite-containing catalyst in the cracking of hydrotreated vacuum gasoil.