Role of macroporosity in macro-mesoporous red mud catalysts for slurry-phase hydrocracking of vacuum residue

Abstract

To improve the catalytic performance of red mud (RM) for slurry-phase hydrocracking of vacuum residue, macro-mesoporosity was introduced into RM using polystyrene and Pluronic F-127 as co-templates in this study. The obtained macro-mesoporous red mud (Ma-RM) catalysts were characterized by nitrogen adsorption, X-ray diffraction, ammonia temperature-programmed desorption, scanning electron microscopy, and transition electron microscopy. Subsequently, they were applied to the slurry-phase hydrocracking of vacuum residue at 490°C for 2h. Comparative reaction tests revealed that Ma-RM exhibited better catalytic behavior for the VR hydrocracking compared to activated RM without macropores. Ma-RM successfully suppressed coke formation and increased liquid yield in products distribution. The macroporous structure of Ma-RM was connected by mesopores containing active sites for hydrogenation. The presence of a macro-mesoporous structure enhanced hydrogenation over the catalysts due to better accessibility to the active sites for hydrogenation, which induced less coke and more liquid yield.