Preparation of Y-type molecular sieve based on bentonite and study of its performance in hydrocatalytic cracking of shale oil

Abstract

Y-type molecular sieve was synthesized hydrothermally using bentonite as the raw material. The study investigated the optimal synthesis conditions and the impact of metal impurities in bentonite on Y-type molecular sieve. Y-1 molecular sieve (synthesized from purified bentonite) has higher crystallinity, stronger acidity, and larger specific surface area, pore size, and pore volume than Y-2 molecular sieve (synthesized from the original bentonite). The elimination of metal impurities from bentonite is advantageous for synthesizing Y-type molecular sieve, as it can significantly enhance its physical properties and structure. HY molecular sieves were prepared by modifying Y-1 and Y-2 through ammonium exchange and were used as catalysts for the hydrocatalytic cracking of shale oil fractions > 350 °C. The findings indicate that the HY-1 catalyst exhibits superior catalytic cracking performance compared to the HY-2 catalyst. The catalyst’s performance is comparable to that of commercial Y-type molecular sieve catalyst. Under the conditions of a solid–liquid ratio of 1 g:20 g, an initial hydrogen pressure of 4 MPa, a reaction time of 50 min, and a reaction temperature of 370 °C, the gasoline yield is 63.38%, heavy oil content is only 3.78%, and coke yield is 0.93%.