Influence of MoS2/TiO2 on the behavior of heavy oil hydrogenation and coke generation

The high tolerance to feed oil makes slurry bed hydrocracking technology one of the main streams of research, but the relationship between hydrogenation and deactivation of slurry bed catalysts remains unclear. In this study, the distribution of vacuum residue (VR) hydrogenation products, coke generation, and catalyst deactivation patterns were analyzed using MoS 2 /TiO 2 as the hydrogenation catalyst. With an increase in the reaction temperature or decrease in the hydrogen pressure, the cracking performance gradually improved, the hydrogenation saturation effect gradually weakened, and the oil-to-coke ratio (OCR) gradually decreased. This implies that the influence of the lightning effect from coke generation gradually increased. The conversion rate of VR to gasoline and diesel components is 3.8 times higher than the conversion rate to coke and gas. At lower temperatures, coke was dominated by graphitic carbon encapsulated on the catalyst surface. As the temperature increased, the content and lamellar diameter of graphitic carbon decreased, and the content of amorphous carbon increased. An increase in temperature also promoted the dealkylation reaction and coke condensation, resulting in a decrease in pyrolytic activity. VR hydrogenation was subjected to kinetic analysis, and a model for MoTi-5-catalyzed VR deactivation was developed using OCR to deduce the degree of contribution of coke generation to lightning.