P/Ce复合改性ZSM-5催化剂的制备及其对重烃催化裂解的反应性能OA

With spent catalyst discharged from a catalytic cracking unit as raw material,an ammonium salt mixing-calcination-hydrothermal slurrying method was adopted to remove Fe and Ni from the spent catalyst,thereby effectively enriching ZSM-5 zeolite.The obtained ZSM-5 zeolite further underwent phosphorus and cerium composite modification to prepare P/Ce composite modified ZSM-5 catalysts.The crystal structure,elemental composition,textural properties,and surface acidity of the catalysts were characterized by XRD,XRF,N2 adsorption-desorption,Py-FTIR,and NH3-TPD.With Yulin atmospheric residue as the feedstock,the activity of P/Ce composite modified ZSM-5 catalysts(Z-1-Z-5)with different Ce loadings in catalytic cracking was evaluated in a fixed-bed microreactor.The experimental results show that P/Ce composite modification does not destroy the MFI framework structure of ZSM-5 zeolite,and mainly regulates the mesoporous structure of the catalyst.The introduction of Ce can significantly increase the amount of Lewis acid sites and optimize the surface acidity.The Z-4 catalyst with a Ce loading of 0.220%(w)exhibits strong heavy hydrocarbon conversion ability(conversion of 91.3%),high ethylene and propylene yield(28.01%),and low coke yield(7.70%),showing excellent catalytic activity.