The TiO2-Al2O3 complex support was prepared by the sol-gel method. A nickel phosphide catalyst, Ni2P/TiO2-Al2O3 with citric acid (CA) as chelating agent, was prepared by the impregnation method. The catalysts were characterized by X-ray diffraction (XRD), N2 -adsorption specific surface area measurements (BET), thermogravimetry-differential thermal analysis (TG-DTA) , temperature programmed reduction (TPR) and transmission electron microscope (TEM). The effects of different chelating agents and CA addition for dibenzothiophene (DBT) hydrodesulfurization (HDS) were studied. The result showed that the addition of appropriate amount of CA into the catalyst can enrich the pores of Ni2P/TiO2-Al2O3 catalyst, increase the surface area, which made better pore structure, higher dispersion of metal active component and more uniform size of the active component. CA can weaken the interaction between the active phase and the support, resulting in an apparent decrease in reduction temperature for nickel and phosphorus precursor as well as promotion of the formation of the Ni-P-O active phase. At reaction temperature of 360℃, pressure of 3. 0 Mpa, hydrogen/oil ratio of 500 (volume ratio) , liquid hourly space velocity of 2. 0 h-1 and reaction time of 4 h, the initial dibenzothiophene conversion was 99. 5% and stabilized at about 95.0% during 48 h reaction.%采用溶胶-凝胶法制备了TiO2-Al2O3复合载体,以柠檬酸(CA)为络合剂采用浸渍法制备了Ni2P负载的TiO2-Al2O3复合载体催化剂,并用X射线衍射(XRD)、N2吸附比表面积(BET)测定、热重-差热分析(TG-DTA)、程序升温氢还原(H2-TPR)和透射电子显微镜(TEM)技术对催化剂的结构和性质进行了表征,考察了加入CA对Ni2P/TiO2-Al2O3催化剂二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响.结果表明,适量的CA可以丰富催化剂的孔道,提高催化剂的比表面积,使催化剂具有更好的孔结构、更高的金属活性组分分散度和更均一的活性组分尺寸.CA的引入可以减弱金属与载体之间的相互作用,显著降低Ni和P前驱体的还原温度,促进Ni-P-O活性相前驱态的生成.在360℃、3.0 MPa、氢油比500(体积比)、液时体积空速2.0h-1的条件下,反应4h时二苯并噻吩转化率达到99.5％.在48 h内二苯并噻吩转化率可稳定在95.0％左右.
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