Catalytic performance and sulfidation behaviors of CoMo/Beta-MCM-48 catalysts prepared with citric acid for FCC gasoline hydroupgrading

摘要

CoMo catalysts supported on Beta-MCM-48 were prepared by different impregnation methods and calcination conditions with the addition of citric acid (CA). The addition of citric acid resulted in an increase of the catalytic activities in gasoline hydroupgrading, which was correlated to the formation of Mo–CA complexes, leading to higher MoS2 dispersion degrees and more amounts of Co–Mo–S active phases. The as-synthesized catalysts were characterized by powder X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and the corresponding catalytic performance of FCC gasoline hydroupgrading was evaluated. The results showed that different impregnation methods and calcination conditions had a certain influence on their catalytic performance. In this research, CA-CoMo/ABM48-S catalyst obtained by two-step impregnation method and air-calcination had the shortest average length of 3.0 nm and the moderate stacking degree of 2.6, therefore, it made a good balance in hydrodesulfurization (HDS), hydroisomerization and aromatization activities, as a result it exhibited the highest HDS efficiency (95.0 %) and the lowest RON loss (0.5 unit).