PREPARATION OF NEW TYPE CATALYST WITH GOOD PROPERTIES FOR HYDRODESULFURIZATION

The CoMo/TiA catalyst for hydrodesulfurization (HDS) and its composite support TiA with industrial scale had been produced through the certain process and the studied range of ratio of TiO₂/(TiO₂ + Al₂O₃) was enlarged. The good properties of the support TiA were attributed to its special pore structure. When the ratio of TiA/(TiA + Al₂O₃) was 0.80, the specific surface area of the support and its pore volume reached their maximum respectively. The range of atom ratio of Co/(Co + Mo) of the catalyst CoMo/TiA from 0.25-0.31 proved best, during which activity of the catalyst reached the maximum. The disperse state of TiO₂ on the surface of TiA and effect of the promoter Co content on the surface structure of the catalyst had been studied by XRD, LRS and XPS. The analytic results showed that 0.47 g TiO₂/g γ-Al₂O₃ was the schwellenwert for the coverage of TiO₂ on the surface of TiA. Beyond this, TiO₂ lies on the surface of TiA with a single layer; otherwise, it existed in the form of TiO₂ crystal phase (anatase phase). When adding a few promoters Co into the catalyst, the dispersity of MoO₃ on the surface of the support TiA increased remarkably and activity of this catalyst was also improved.