Zeolite y Mother Liquor Modified γ-Al₂O₃ with Enhanced Brönsted Acidity as Active Matrix to Improve the Performance of Fluid Catalytic Cracking Catalyst

A new matrix material for the fluid catalytic cracking (FCC) catalyst was prepared using the zeolite Y mother liquor to modify the surface acidity of γ-Al₂O₃. The modified γ-Al₂O₃ was characterized using a variety of techniques, and the relationship between surface acidity and catalytic performances in the catalytic cracking of vacuum gas oil (VGO) was correlated. Characterization results showed that Brönsted acid sites derived mainly from isolated silanol groups, which increased on modified γ-Al₂O₃, while Lewis acid sites reduced dramatically after modification. Correlation results indicated that increased Brönsted acid sites effectively improved the conversion of VGO. In addition, new medium strong acid sites engendered at the interfaces of γ-Al₂O₃/amorphous silica-alumina or γ-Al₂O₃/zeolite Y played a critical role in determining the final product distribution, leading to yields of gasoline and liquefied petroleum gas higher than those of the pure γ-Al₂O₃ derived catalyst.