THE EFFECTS OF ZRP ZEOLITES ON FCC GASOLINE CATALYTIC CRACKING FOR PROPYLENE

The catalytic cracking reaction of FCC gasoline over ZRP zeolites under 550℃,atmospheric pressure and with steam for production of propylene,and the effects ofn(SiO2)/ n(Al2O3) and the modification of ZRP by rare earth elements on the cracking reaction were investigated..The experimental results and calculated distribution of reactants and products showed that the propylene was obtained by the cracking reaction of olefin in FCC gasoline.Increasing the conversion of olefin,promoting the cracking reaction and increasing the selectivity of propylene would be in favor of increasing the yield of propylene.The ZRP zeolite with high n(SiO2)/n(Al2O3) possessed more strong acid so that the conversion of olefin and the selectivity of light olefin were both increased.But the selectivity of butylene was higher than that of propylene.The ZRP zeolite modified with rare earth also possessed more strong acid,over which in cracking reaction of FCC gasoline,not only increased the conversion of olefin,but also the selectivity of propylene increased,resulting in the olefin conversion of 74.32%,the olefin mass fraction of 18.20% in cracking gasoline and the propylene selectivity of 45.91%.