Catalytic Cracking of VGO by Zeolite–kaolin Mixed Catalysts Using Curie Point Pyrolyzer

Mixed composite catalysts including three types of zeolite (Y, β and ZSM-5), kaolin and binder (Al 2 O 3 ) were prepared as a model of an industrial catalyst for catalytic cracking and were tested in the catalytic cracking of VGO using a Curie point pyrolyzer (CPP) as a simple estimation method of catalysts for catalytic cracking. The mixed catalysts consisted of 26 wt% of zeolite, 58 wt% of kaolin and 16 wt% of a binder (Al 2 O 3 ). The three mixed catalysts using Y (Si/Al 2 ＝ 5.5), β (37), ZSM-5 (90) zeolites were named MAT(kaolin)-Y, MAT(kaolin)- β and MAT(kaolin)-Z, respectively. MAT(kaolin)-Y and MAT(kaolin)- β showed higher selectivity for gasoline and higher RON value, and produced larger amounts of olefin and multi-branched products compared with single zeolite. These results indicated that both inhibition of over-cracking and dispersion of acid sites of zeolite were important to increase RON value. The SiO 2 /Al 2 O 3 ratio of ZSM-5 used in this study was 90, and thus the density of acid sites of the mixed catalyst was much smaller than those for other zeolites used. Therefore, addition of kaolin to ZSM-5 significantly reduced the activity and the product selectivity. In this paper, the CPP method was found to be a simple and convenient tool to investigate the characteristics of catalysts for catalytic cracking of heavy feedstock such as VGO.