Preparation of Y Zeolite Molecular Sieve Based on Bentonite and its Catalytic Cracking Performance for Shale Oil

Abstract

In this paper, Y-type molecular sieve was prepared by hydrothermal synthesis method using bentonite as raw material, which reduced the preparation cost of traditional molecular sieve and improved the comprehensive resource utilization rate of bentonite. The effect of metal composition in bentonite on the preparation of Y-type molecular sieve and the catalytic cracking performance of shale oil was investigated. XRD, SEM, FT-IR, BET and other characterization methods were used to investigate the physicochemical properties. The results showed that the Y-type molecular sieve prepared with bentonite as raw material has good morphology, small grain square block, high crystallinity, high acidity, and better specific surface area, pore size and pore volume. Compared with the Y-type molecular sieve (HY-2) prepared by the bentonite containing Fe, the Y-type molecular sieve catalyst (HY-1) prepared by the bentonite removing impurities such as metal Fe has higher crystallinity, stronger acidity, larger specific surface area, pore size and pore volume. The results show that removing metal Fe and other impurities from bentonite is beneficial to the synthesis of Y-type molecular sieve and can effectively improve its physical property structure. The catalytic cracking performance of the catalyst was investigated by using shale oil >350℃ fractions. The results showed that the content of gasoline and LPG reached 46.03% and 2.51%, the content of diesel oil was 41.14%, the content of dry gas and heavy oil was 0.87% and 8.28%, and the content of coke was as low as 1.16%. Compared with HY-2, the gasoline content of HY-1 reaction products is 56.66%, an increase of 10.63%, while the diesel and heavy oil contents are 32.89% and 6.43%, respectively, a decrease of 8.25% and 1.82%, indicating that HY-1 has stronger catalytic cracking performance and can convert more heavy oil and diesel into gasoline. Compared with commercial Y-type molecular sieve catalyst, the gasoline content of HY-1 is only 3.68% lower, while the coke content is 2% lower, indicating that the Mg and K contained in bentonite are conducive to the catalytic cracking reaction and improve the production of light oil. At the same time, the catalytic cracking performance of HY-1 has reached the performance of commercial products, and has high commercial value and research potential. By optimizing the reaction conditions, the gasoline yield of HY-1 reached 63.38%, an increase of 6.72%. The heavy oil content is only 3.78%, which is reduced by 2.56%, and has a lower coke rate of 0.93%. Therefore, it shows that the bentonite-based Y-type molecular sieve has good catalytic performance, which can reduce the cost of Y-type molecular sieve catalyst, improve the utilization rate of shale oil heavy oil, and create certain economic value.