Abstract
Active metal combination and metal loading effects on hydrogenation (HY) and hydrocracking (HC) activities of Ni-W sulfide catalysts were investigated in order to control these binary functions. A series of W and Ni-W catalysts supported on γ-Al2O3 were prepared using an impregnation method. Loadings of active metal such as W and Ni were varied, while a metal loading ratio of W and Ni was kept constant in the Ni-W catalysts. Another series of Mo and Ni-Mo catalysts were also prepared to clarify differences in catalytic functions between Ni-W and Ni-Mo catalysts. After presulfiding each catalyst, two kinds of model test reactions, using 1-methylnaphthalene (1-MN) and diphenylmethane (DPM), were carried out to evaluate HY and HC activities of the catalysts, respectively.
For hydrogenation (HY), Ni-W catalysts showed much higher activities than the W catalysts, while for hydrocracking (HC), lower activities were observed over the Ni-W catalysts as compared to those over the W catalysts, indicating that HY active sites appeared and HC active sites disappeared by the active metal combination of W and Ni. The HY and HC activities of the Ni-W catalysts increased as the metal loadings were increased. In the meanwhile, HY activities reached saturation at around formation of a monolayerloading of the active metals.
When comparing Ni-W catalysts with Ni-Mo catalysts the former showed higher HY activities at higher reaction temperature than the latter. Higher HY activity of the Ni-W catalysts were obtained at higher metal loading.
After optimizing physical and chemical properties of Al2O3 support and active metal loadings of Ni and W, the Ni-W catalyst was used for the upgrading of coal-derived kerosene. Since HY activities of the Ni-W catalysts are easily poisoned by sulfur containing compounds in the feed, a coal-derived liquid containing less amount of sulfur was used for the feed for the upgrading. The Ni-W catalyst gave superior hydrogenation (HY) and hydrodenitrogenation (HDN) activities as compared to Ni-Mo catalysts.
