Estimation of Catalytic Cracking of Vacuum Gas Oil by a Y Zeolite-Containing Two-Layered Catalyst and a Novel Three-Layered Hierarchical Catalyst Using a Curie Point Pyrolyzer Method

A Y zeolite-containing two-layered catalyst and a novel three-layered hierarchical catalyst were prepared using a template and the gel skeletal reinforcement (GSR) method. Initially, two-layered catalysts were prepared by the sol-gel method using malic acid as the template in the presence of HY zeolite (HYZ). The two-layered hierarchical catalyst, 2L(S-HYZ), consisted of 50 wt % the mesoporous part of silica (S) and 50 wt % the microporous part of HYZ. The three-layered hierarchical catalyst, 3L(GSR-S)2L(S-HYZ), was made by GSR silica (GSR-S) production in the presence of 2L(S-HYZ) where silica gel particles including 2L(S-HYZ) inside were reinforced by a reinforcing solution of hexamethyldisiloxane-acetic anhydride before aging and successive calcination and consisted of 50 wt % large-mesoporous GSR-S and 50 wt % the 2L(S-HYZ) hierarchical catalyst. It was confirmed by XRD and N-2 adsorption and desorption measurement that this catalyst possessed three characters of microporous zeolite crystals, small mesoporous silica, and large mesoporous silica. Catalytic cracking of vacuum gas oil over these hierarchical catalysts was performed using a Curie point pyrolyzer method. 3L(GSR-S)2L(S-HYZ)(Z25), which included 25 wt % HYZ, exhibited the highest activity. Further, it was proposed that the activity could be related to not only the amount of acid sites but also the size of mesoporous pore volume.