A new way to enhance the porosity and Y-faujasite percentage of in situ crystallized FCC catalyst

摘要

An in situ crystallized FCC catalyst with high porosity and high Y-faujasite percentage was successfully synthesized via adding a lab made porosity enlarging agent (PEA) to kaolin clay. The in situ crystallized microspheres (CMS) had a pore volume of 0.462 mL g~(-1), a specific surface area of 406 m~2 g~(-1), and a Y-faujasite content of over 60%. Densely packed Y-faujasite crystals and abundant macropores can be observed on the surface of the in situ crystallized microspheres. After ion exchange with NH4NO3 solution and rare earth lanthanum, the crystallized microspheres had an attrition index of 2.2% h~(-1), meeting the commercial requirements of FCC catalysts. The ratio of Bronsted sites to Lewis sites was 2.8, and the ratio of weak, medium and strong acid sites was 1.83:1.33:1. The resulting catalyst had a good hydrothermal stability. Its catalytic performance in cracking mixing oil displayed high selectivities to gasoline and light oil, and low selectivities to dry gas and coke.