Development of new ZSM-5 catalyst-additives in the Fluid Catalytic Cracking process for the maximization of gaseous alkenes yield

The catalytic activity of gallium, chromium or copper modified H-ZSM-5 zeolite as Fluid Catalytic Cracking (FCC) catalyst-additive was tested in this study. The partial ion-exchange of H-ZSM-5 with copper hindered framework dealumination upon severe steaming and resulted in significant increase of light alkenes (propylene and butylenes). The gallium and chromium impregnated H-ZSM-5 zeolites were more selective with regard to light alkenes compared to the unmodified H-ZSM-5 sample, but were not as active as the Cu-exchanged sample. An optimum balance between the number/strength of acid sites and the type/amount of metals in the modified H-ZSM-5 catalyst-additives is required for maximization of light alkenes with relatively low gasoline loss and low coke formation.