加氢处理催化剂的制备和表征Ⅱ.制备方法对MoNiP/Al_2O_3催化剂性质的影响

Preparation and Characterization of Hydrotreating CatalystsⅡ. Effect of Preparation Methods on Properties of MoNiP/Al_2O_3 Catalyst

从实用的角度出发 ,比较了不同制备方法 (干混法、干混 浸渍法和共浸渍法 )对MoNiP/Al2 O3 催化剂性质的影响 .结果表明 ,采用干混法制备的催化剂 ,活性金属 (Mo ,Ni)在其表面上虽然有较高的分散度 ,但其分散状态较差 ,因而影响其催化活性 ;采用干混 浸渍法和共浸渍法制备的催化剂 ,可以克服上述缺点 ,使活性金属在其表面上既有较高的分散度 ,又有优良的分散状态 ,因而催化活性较高 .此外 ,采用干混 浸渍法制备的催化剂 ,有较大的比表面积和较大的孔容 ,而采用共浸渍法制备的催化剂 ,有较大的孔直径和较高的机械强度 .活性评价实验结果表明 ,MoNiP/Al2 O3 催化剂的最佳焙烧温度为 45

Three methods for preparing hydrotreating catalysts, such as dry mixing (DM), dry mixing followed by impregnation (DM I) and co impregnation (CI), were compared. The experimental data indicated that the active metals Mo and Ni on the surface of MoNiP/Al 2O 3(DM) catalyst have high dispersion degree and worse dispersion state. For MoNiP/Al 2O 3(DM I) catalyst, the active metals have both good dispersion state and high dispersion degree. Based on a newly developed support γ Al 2O 3, MoNiP/Al 2O 3(CI) catalyst was prepared and its properties are very similar to MoNiP/Al 2O 3(DM I) catalyst. Hence, the HDN activity of both MoNiP/Al 2O 3(CI) and MoNiP/Al 2O 3(DM I) is obviously higher than that of MoNiP/Al 2O 3(DM) catalyst. In addition, MoNiP/Al 2O 3(DM I) catalyst has larger surface area and pore volume, being suitable for hydrotreating hydrocarbon fractions, such as VGO (vacuum gas oil) and AGO (atmospheric gas oil). While MoNiP/Al 2O 3(CI) catalyst has larger pore size, being suitable for hydrotreating hydrocarbon fractions with larger molecular size, such as petroleum wax, vaseline, etc . The results of evaluation tests showed that the optimal calcination temperature for MoNiP/Al 2O 3 (CI) catalyst is 450 ℃.