Multi-metal catalysts for slurry-phase hydrocracking of coal-tar vacuum residue: Impact of inherent inorganic minerals

Multi-metal catalysts for slurry-phase hydrocracking of coal-tar vacuum residue were investigated. The multi-metal catalysts system consisted of pyrrhotite (Fe1-xS) transformed from inherent inorganic minerals in coal-tar vacuum residue and mixed molybdenum (Mo)-nickel (Ni) sulfide catalysts. The inherent inorganic minerals included iron oxide (hematite-Fe2O3, goethite-FeO(OH)) and other minerals. The formed pyrrhotite (Fe1-xS) was acting as an active phase for hydrocracking. Mo naphthenate and Ni naphthenate were used as precursors to the dispersed Mo-Ni sulfide catalysts. The multi-metal sulfide catalysts were confirmed to form and well dispersed across the toluene insoluble sample by XRD, XPS and EDS analysis during hydrocracking. Comparative reaction tests revealed that the inherent inorganic minerals, as Mo-Ni catalyst carrier and coke carrier, enhanced the dispersion of Mo-Ni catalysts and induced less coke formation. Compared with only the Mo-Ni catalysts or inherent inorganic minerals, the multi-metal catalysts system promoted the thermal decomposition of CTVR feedstock at a low temperature, and suppressed coke formation, increased the liquid yield and improved hydrodeheteroatom at a high temperature, which resulted from the synergistic effects between the Mo-Ni sulfides and the inherent inorganic minerals.