Characterization and cracking performance of zirconium-modified Y zeolite

Zirconium-modified Y zeolites (ZrUSY) were prepared by impregnation of the zeolite with anhydrous-ethanol and aqueous ion exchange methods. The ZrUSY samples were characterized by powder X-ray diffraction, nitrogen physisorption, and Fourier transform infrared spectroscopy. The results indicated that ZrUSY prepared by the impregnation with anhydrous-ethanol method showed higher crystallinity, specific surface area and hydrothermal stability. The incorporation of Zr into other Y zeolites leads to an increase of the Brønsted acid site concentration and a decrease of the Lewis acid site concentration compared to the ultra-stable Y zeolite (USY). The ZrUSY was much more favorable towards heavy oil FCC conversion with decreasing coke yield and improving olefins selectivity.