Optimized Zeolite Distribution of FCC Catalysts for Promoting Heavy-Oil Catalytic Cracking

The accessibility of cracking active components, mainly zeolite Y, to heavy oil molecules is the key factor to determine the performance of FCC catalysts. In this study, a novel FCC catalyst with Y zeolite components synthesized via in situ crystallization on kaolin microspheres has been designed and prepared. The distribution of the zeolite Y in the FCC catalyst microspheres has been characterized by scanning electron micros-copy (SEM) and high-resolution field emission scanning electron microscopy (HR-FESEM). Differing from the random distribution of zeolite components in a commercial FCC catalyst prepared via a spray drying technique, the Y zeolite components are concentrated on the surface of the in situ crystallization FCC catalyst microspheres. The unique distribution characteristics lead to the distinctive structural properties, such as texture constructions and acid properties, mass transfer performance, and zeolite accessibility. The catalytic cracking performance of heavy oil macromolecules of the two catalysts has been investigated using a microactivity test (MAT) and advanced catalyst equipment (ACE). Based on the results, we can conclude that the unique distribution of the zeolite Y on the surface of in situ crystallization FCC catalyst microspheres plays an important role for promoting a greater ability for conversion of heavy oil, higher gasoline selectivity, and lower byproduct yield.