摘要
本文考察了ＣｏＭｏ／ＴｉＯ３和ＣｏＭｏ／γ－Ａｌ２Ｏ３催化剂的加氢脱硫性能及表面结构变化和预处理条件对其活性的影响．担体ＴｉＯ２（Ａ）和ＴｉＯ２（Ｂ）分别采用ＴｉＣｌ４中和法和ＴｉＯＳＯ４水解法制备．结果表明，催化剂的活性顺序为ＣｏＭｏ／ＴｉＯ２（Ａ）＞ＣｏＭｏ／ＴｉＯ２（Ｂ）＞ＣｏＭｏ／γ－Ａｌ２Ｏ３催化剂的预处理条件对催化剂的加氢脱硫（ＨＤＳ）和加氢（ＨＹＤ）活性有很大影响，ＴｉＯ２担体上Ｍｏ物种主要以八面体配位构型存在，Ｍｏ６＋更易于还原成低价态．
ydrodesulfurization activity of CoMo/TiO2 and CoMo/γ-Al2O3catalysts was examined by using a microreactor operating at 3. 0 MPaH2pressure.The surface structure and reducibility in H2 at 450℃ of these catalysts were characterized by LRS and XPS. For CoMo/TiO2 catalysts, TiO2 carrier was prepared by two methods:TiO2(A) was prepared by using ammonium water neutralizing TiCl4 solution, while TiO2 (B) was prepared by the hydrolysis of TiOSO4 Before the measurement of thiophene HDS and cyclohexene HYD, the catalysts were pretreated by sulfiding or reducing or without any treatment.The results obtained are: (1) The HDS and HYD activities of CoMo/TiO2 (A) and CoMo/TiO2(B) catalysts are much higher than that of CoMo/γ-Al2O3 catalyst.The obvious influence of preparation technology of TiO2 carrier on the CoMo/TiO2 catalyst can be observed.(2) Pretreating conditions obviously influence the HDS and HYD activities of CoMo/TiO2 (A),(B)and CoMo/γ-Al2O3. The best way is presulfiding treatment in H2-H2S at 400℃ For CoMo/TiO2 catalyst without any pretreatment relatively high activity is exhibited, which is of significance in terms of industrial application. (3) The surface structure of CoMo/TiO2 catalyslts is differeht from CoMo/γ-Al2O3. LRS spectra show that the strong band of bridged Mo-O-Mo species existed in CoMo/TiO2 (A), XPS results demonstrate that more Mo6+ species of CoMo/TiO2 than that of CoMo/γ-Al2O3 can be reduced to Mo4 + ions, which. reveals that TiO2 carrier can favor the reduction of Mo6+ species.
关键词
加氢脱硫
钴钼催化剂
CRS
XPS
ydrodesulfurization,CoMo/TiO_2, CoMo/γ-Al_2O_3, LRS,XPS
