Research Of High Silica Y Type Molecular Sieve Catalytic Cracking Catalyst

Fluid catalytic cracking (FCC) process is a core technology in modern petroleum refineries. The feedstock for FCC units is mixed into higher and higher proportion of heavy feedstock, as crude oil being heavy and of poor quality in these years. So, developing of highly effective and stable FCC catalyst is urgent.Zeolite Y is one of the most important active components of FCC catalyst. It is well known that the performance of Y zeolite such as stability, acidity and selectivity could be greatly improved by increasing the its silica to alumina ratio (SiO2/Al2O3). In the present work, high silica NaY zeolite, which shares a SiO2/Al2O3ratio of6.0or above, was synthesized using direct synthesis method. Synthesis conditions were optimized and the high silica NaY zeolite was obtained with cheap industrial material and without template agent.A number of successful middle scale experiments are done with the optimized formulation, the high silica NaY zeolites are produced and characterized by XRD, SEM. The results show that those products have no mixed crystal, their relative crystallinity is above95%, and SiO2/AlO3ratio of products is increased1.3units compared to industry standard sample. The crystal size of high silica NaY zeolite is smaller and homogeneous. Compared to the industry standard sample, the surface area is increased by40m2/g, the framework collapse temperature is enhanced by44℃in average, which shows excellent thermal stability.After the high silica NaY zeolites were modified by rare earth feeding and hydrothermal treatments, REUSY zeolites were obtained. The modified REUSY zeolites are used to prepared FCC catalysts, whose cracking performances are investigated and compared to the normal industrial FCC catalysts. The obtained result shows that the gasoline selectivity and hydrogen transfer activity of the present catalyst named C-2, is excellent, and the yield of gasoline is higher, the yield of coke and bottom oil is lower than normal industrial FCC catalysts. At the mean time, the olefin content in the gasoline is reduced and the octane number is keeping.C-2shows good adaptability for all kinds of feedings and hydrothermal stability. It’s suitable to be industrial FCC catalyst.