Selective Formation of Light Olefins by the Cracking of Heavy Naphtha over Acid Catalysts

摘要

The catalytic cracking of heavy naphtha was carried out over various types of proton form zeolites such as of H-ZSM-5, H-Mor, H-Beta, and SAPO-11 for the selective production of ethylene (C_2~=) and propylene (C_3~=). Among them, the H-ZSM-5 showed the highest olefin selectivity and propylene yield. The yield of light olefins and product distribution were also strongly influenced by the concentration and strength of acid sites. Maximum yield of ethylene and propylene was obtained over H-ZSM-5 with the lowest Si/Al ratio. In the optimized reaction conditions, the C_2~= + C_3~= yield of 48.5 wt % with C_2~= /C_3~= ratio of 0.90 was obtained.