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采用NH3-TPD、SEM-EDS、XRD、压汞法等方法考察不同TiO2含量对重整石脑油选择性加氢催化剂MoNi/γ-Al2O3-TiO2物化性质的影响,并进行了TiO2含量与催化剂加氢活性及加氢选择性的关联实验。结果表明,MoNi/Al2O3-TiO2催化剂的酸性中心以弱酸、中强酸为主;随着载体中TiO2含量的增加,催化剂比表面积、总酸量降低,催化剂侧压强度略有下降。载体γ-Al2O3-TiO2中以γ-Al2O3为骨架结构,TiO2和γ-Al2O3之间存在相互作用,形成均匀的复合载体;载体表面上具有较发达的孔结构。当TiO2质量分数小于10%时,TiO2在载体中均匀分散;随着TiO2含量进一步增加,TiO2聚集加快,晶粒增长迅速,出现了TiO2的锐钛矿晶相。TiO2质量分数为10%时,活性组分Al、Ti、Mo、Ni均匀分布在MoNi/γ-Al2O3-TiO2催化剂中。在重整石脑油的选择性加氢反应中,随着载体中TiO2含量的增加,催化剂的加氢活性有所降低,但加氢选择性提高。
The effect of different TiO2 content on the physicochemical properties of reformer naphtha selective hydrogenation catalyst MoNi / γ-Al2O3-TiO2 was investigated by NH3-TPD, SEM-EDS, XRD and mercury intrusion porosimetry. The effects of TiO2 content and catalyst Correlation Experiment of Hydrogenation Activity and Hydrogenation Selectivity. The results show that the acidic sites of MoNi / Al2O3-TiO2 catalyst are mainly weak acid and medium strong acid. With the increase of TiO2 content in the catalyst, the specific surface area and total acid amount of the catalyst decrease, and the lateral pressure of the catalyst decreases slightly. The carrier γ-Al 2 O 3 -TiO 2 has γ-Al 2 O 3 as the framework structure, and there is interaction between TiO 2 and γ-Al 2 O 3 to form a uniform composite support. The carrier has a well-developed pore structure on the surface. When the mass fraction of TiO2 is less than 10%, the TiO2 is uniformly dispersed in the carrier. With the further increase of TiO2 content, the aggregation of TiO2 accelerates and the grains grow rapidly and the anatase phase of TiO2 appears. When the mass fraction of TiO2 is 10%, the active components Al, Ti, Mo and Ni are uniformly distributed on the MoNi / γ-Al2O3-TiO2 catalyst. In the selective hydrogenation of the reformed naphtha, the hydrogenation activity of the catalyst is reduced with the increase of TiO2 content in the carrier, but the hydrogenation selectivity is increased.