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 degrees C for 2 h. 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. (C) 2013 Elsevier B.V. All rights reserved.