Performance of Zr- and P-modified USY-based catalyst in hydrocracking of vacuum gas oil

• Published in: Fuel processing technology 2013-02, Vol.106, p.439-446
• Main Authors: Cui, Qingyan, Zhou, Yasong, Wei, Qiang, Yu, Guanglin, Zhu, Li
• Format: Article
• Language: English
• Subjects: Acidity; Applied sciences; catalysts; Crude oil, natural gas and petroleum products; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; hydrogenation; Hydrogenation activity; Middle distillate; oils; Phosphorus; Processing of crude oil and oils from shales and tar sands. Processes. Equipment. Refinery and treatment units; slabs; synergism; USY; zeolites; Zirconium
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2012.09.010

USY zeolites were modified by zirconium, phosphorus and both zirconium and phosphorus, and the corresponding catalysts were prepared for hydrocracking of vacuum gas oil. The results showed that Zr-modified USY enhanced W species dispersion on catalyst surface, weakened interaction of W species with support and improved W species reducibility, leading to formation of highly stacked WS2 slabs and higher sulfidation degree of W species, which was favorable for the enhancement of hydrogenation activity. The influence of the modification with zirconium and phosphorus on these properties of catalyst was more pronounced than that of zirconium or phosphorus modification because of the synergistic action of phosphorus and zirconium. The catalyst containing Zr-USY had slightly lower hydrocracking activity than that containing USY owing to a diminution of acid sites, but presented obviously greater middle distillate selectivity arising from the improvement of hydrogenation activity. The middle distillate selectivity on catalyst containing Zr-P-USY was higher than that on catalysts containing Zr-USY or P-USY, corresponding to its more effective catalyst properties. ► Zr-P modification weakens interaction of W species with support. ► Zr-P modification increases stacking layers of WS2 slabs. ► Zr-P modification improved the sulfidation degrees of W species. ► Catalyst containing Zr-P-USY presented higher selectivity to middle distillates.