Abstract: ZSM-5 zeolites were modified with phosphorus by incipient-wetness impregnation method, hydrothermal dispersion method and high-temperature hydrothermal method, respectively. The phosphorus modified zeolites were analyzed by XRD, TEM, SEM, etc. The performance of increasing propylene production in FCC process was evaluated. The results showed that the pore volume and the acidity of the modified zeolites increased with the increase of the modification temperature. The interaction between P and zeolites was weak by incipient-wetness impregnation, and strong by hydrothermal dispersion or high-temperature hydrothermal. The evaluation results showed that the propylene yield of the additives with ZSM-5 modified by hydrothermal dispersion was the highest, reaching 12.43%.

Key words: modification process, ZSM-5 zeolite, phosphorus modification, catalytic cracking, propylene