Modification of the Acidic and Textural Properties of HY Zeolite by AHFS Treatment and Its Coke Formation Performance in the Catalytic Cracking Reaction of N-Butene

Coke formation on n-butene cracking catalyst is the main reason for reducing of its lifetime. To study effects acidity and textural properties coke process, a series HY zeolite-type catalysts were prepared by ammonium hexafluorosilicate treatment (AHFS). NH3-TPD Py-IR-TPD used to systematically change law zeolite acidity. It was found that with increase AHFS concentration, acid density decreased, whereas ratio Brønsted Lewis first increased then decreased. Meanwhile, percentage inside supper cages strength degree dealumination. Combined in situ IR formation, relationship between coking site revealed. rate zeolites affected density, which decreased decline density. When remains at same level, it determined rate—the stronger strength, faster rate.