磷镍物质的量比对溶剂热法制备的磷化镍催化剂加氢脱硫性能的影响

以三苯基膦(PPh3)为磷源,以三正辛胺(TOA)为液相反应体系,采用溶剂热法制备了负载型Ni-P(x)/MCM-41催化剂(x为初始P/Ni物质的量比),并用X射线衍射(XRD)、N2吸附比表面积测定(BET)、CO吸附、X射线光电子能谱(XPS)和TEM对催化剂进行了结构表征。以含质量分数1%二苯并噻吩(DBT)的十氢萘溶液为原料,在连续固定床反应装置上,研究了初始P/Ni物质的量比对加氢脱硫(HDS)性能的影响。结果表明,在初始P/Ni物质的量比为0.5时,生成的磷化镍物相为以Ni12P5为主,含有少量Ni2P的混合相;初始P/Ni物质的量比大于0.5时,可得到纯Ni_2P相,且随着P/Ni物质的量比的提高,Ni2P晶粒粒径减小,分散度提高。在反应温度613 K,压力3.0 MPa,H_2/oil体积比500,质量空速2.0 h-1时,Ni-P(6)/MCM-41和Ni-P(10)/MCM-41催化剂的DBT转化率接近100%。

Effect of P/Ni ratio on the structure and hydrodesulfurization performance of nickel phosphide catalyst prepared by the solvothermal method

A series of MCM-41-supported Ni_xP catalysts was prepared by the solvothermal method using low-price triphenylphosphine as phosphorus material and tri-n-octylamine as coordinating liquid reaction system. They were characterized with X-ray diffraction, N₂ sorption, CO sorption, X-ray photoelectron spectroscopy and transmission electron microscopy techniques. The effects of initial P/Ni molar ratio on their structures and hydrodesulfurization performances were investigated in a lab-scale continuous flow fixed-bed reactor by feeding 1% of dibenzothiophene (DBT) in decahydronaphthalene. It was shown that Ni₁₂P₅ was primarily formed with a small amount of Ni₂P at the initial P/Ni molar ratio of 0.5. When the initial P/Ni molar ratio was higher than 0.5, pure Ni₂P phase was generated, and its crystal size decreased, and thus, its dispersion increased with the increase of initial P/Ni molar ratio. At 613 K, 3.0 MPa, H₂/oil ratio of 500 (volume ratio), and weight hourly space velocity of 2.0 h^-1, the DBT conversion nearly reached 100% on both the Ni-P(6)/MCM-41 and the Ni-P(10)/MCM-41 samples.