Mo supported on natural rectorite catalyst for slurry-phase hydrocracking of vacuum residue: An effect of calcination

In order to develop high-efficiency and low-cost catalyst for the slurry-phase hydrocracking of vacuum residue (VR), the catalyst supported on natural rectorite was prepared, and the effect of calcination modification of rectorite on the catalyst properties and performance was investigated. The support of rectorite and catalyst were characterized by XRD, FTIR, Py-FTIR, H2-TPR and XPS to examine their structures and properties. The comparative reaction results show that VR conversions for the catalysts supported on calcined rectorite were similar with that on raw rectorite, possibly due to the VR cracking reaction controlled by the thermal cracking following free radical mechanism because of few acid sites observed on the catalysts surface. However, the yields of naphtha and middle distillates for the various catalysts were obviously different, and increased following as Rec-Mo (40.4 wt%) < Rec-600-Mo (52.7 wt%) < Rec-450-Mo (53.5 wt%) < Rec-500-Mo (61.7 wt%), indicating that the calcination of rectorite favored the enhancement of the yields of naphtha and middle distillates for the catalyst in the slurry-phase hydrocracking process, it is attributed that the higher sulfidation degree of molybdenum oxide species on the catalyst surface promoted hydrogenation reaction, thus restrained over-cracking reaction of intermediate product to produce gas.