ACCESSIBILITY STUDY OF BRONSTED ACID SITE IN USY ZEOLITE

Abstract

Abstract: The accessibility of the Bronsted acid center of the USY is the key factor to catalytic cracking performance. The physical properties and structural parameters of USY and HY zeolites were investigated by in-situ infrared specrum technique using pyridine, 2, 6-dimethylpyridine, and 2,6-di-tert-butylpyridine as probe molecules. The MAT evaluation was conducted using Dagang light diesel fraction as feed. It was found that the accessibility of the Bronsted acid sites in the supercages of the USY zeolite to the larger-sized probes is significantly better than that of the conventional HY zeolite. It was concluded that lower Bronsted acid density is the main reason that USY zeolite showed superior Bronsted acid center accessibility in the cage. The MAT of USY zeolite was 69%, higher than that of conventional HY zeolite.

Key words: USY zeolite, Bronsted acid site, supercage, accessibility, in-situ infrared spectrum

CLC Number:

References

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