新型Mo/TiO_2的噻吩加氢脱硫性能

THIOPHENE HYDRODESULFURIZATION OF A NOVEL Mo/TiO_2 CATALYST

以二氧化钛(TiO2)晶须成型材料为载体,采用过量浸渍法制备了MoO3负载量为7.2%(质量分数)的新型Mo/TiO2加氢脱硫催化剂。利用XRD、BET等手段对该催化剂进行表征,并且在催化剂中压微反活性评价装置上考察了不同操作条件对其噻吩加氢脱硫性能的影响。结果表明,新型Mo/TiO2为纯锐钛矿相;TiO2晶须成型载体负载了7.2%MoO3后,比表面积由93m2/g变为72m2/g,孔容由0.27cm3/g变为0.23cm3/g,下降均不明显。该Mo/TiO2催化剂直接用于噻吩加氢脱硫反应时,5h内即达较高活性,能把模型溶液中的噻吩质量分数由1300μg/g降至5μg/g以下。在反应温度300～330℃、H2分压1.5～3.0MPa、氢/油体积比155～250、体积空速3.0～5.0h-1的条件下,新型Mo/TiO2催化剂上噻吩加氢脱硫转化率接近100%,运行500h没有明显失活迹象。

A novel Mo/TiO2 catalyst with the MoO3 loading of 7. 2% （mass fraction） used for hydrodesulfurization（HDS） of thiophene was prepared by the impregnation method, in which mesoporous titania whisker （TiO2） molding material was used as the support and ammonium heptamolybdate [（NH4）6Mo7O24·4H2O] solution as the impregnation solution. The catalyst was well characterized by some techniques, such as X-ray diffraction （XRD）, N2 adsorption-desorption, and its HDS activity for thiophene was evaluated in a continuous-flow fixed-bed micro-reactor under different reaction conditions. Furthermore, the stability of novel Mo/TiO2 catalyst in HDS reaction of thiophene was also investigated. The results indicated that the novel catalyst was in anatase phase. The specific surface areas of TiO2 whisker and novel Mo/TiO2 catalyst were 93 m^2/g and 72 m^2/g, their pore volumes were 0. 27 cm^3/g and 0. 23 cm^3/g, respectively, and there was no obvious reduction in specific surface area and pore volume between them. When the Mo/TiO2 catalyst was used to catalyze the HDS of thiophene, its activity could reach higher level in 5 h, and the mass fraction of thiophene in model solution could be reduced from 1300μg/g to 5μg/g. The thiophene conversion of HDS over the Mo/TiO2 catalyst could reach near 100% under reaction temperatureof300--330℃, H2 pressure of 1.5-3.0 MPa, H2/oil volume ratio of 155-250 and LHSV of 3.0-5.0 h^-1 , and no obvious evidence of deactivation for the catalyst could be seen after running for 500 h.