Pore Structure and Catalytic Performance of Steam-Dealuminated ZSM-5／Y Composite Zeolites

1. Introduction FCC (fluid catalytic cracking) is the major processin which catalysts play a very important role. Zeolites,especially zeolite Y and ZSM-5 that are widely used incatalytic cracking catalysts because of their unique porestructures and stro…

Pore Structure and Catalytic Performance of Steam-Dealuminated ZSM-5/Y Composite Zeolites

For investigating the effect of dealumination on the pore structure and catalytic performance, ZSM-5/Y composite zeolites synthesized in situ from NaY gel were dealuminated by steaming at different temperatures. XRD (X-ray diffraction) characterization indicates that the relative crystallinity of the composite zeolites decreases with the increase in Si/Al ratio after steaming. N2 adsorption-desorption suggests that more mesopores are formed while the BET (Brunauer, Emmett and Teller) specific surface area and the micropore specific surface area decrease as the temperature of steaming rises. Daqing heavy oil was used as feedstock to test the catalytic cracking activity of ZSM-5/Y composite zeolites. The experimental results of the catalytic cracking performance reveal that the distribution of products differs due to the different conditions of hydrothermal treatment. Further hydrothermal treatment leads to an increase in the yield of light oil, and a decrease in the yield of gas products and coke.