Pt负载位置对双功能催化剂正十二烷加氢异构化性能影响

将金属Pt分别负载在Al₂O₃和ZSM-22分子筛上，然后分别与等质量的HZSM-22分子筛和Al₂O₃混合制备2种复合双功能催化剂Pt/Al₂O₃+HZSM-22和Pt/HZSM-22+ Al₂O₃。采用XRD、BET、NH₃-TPD、SEM、ICP以及TEM表征手段对载体和催化剂进行分析。在固定床反应装置上以正十二烷为正构烷烃模型化合物，考察了复合双功能催化剂对正十二烷加氢异构性能的影响。结果表明：金属Pt的负载位置直接影响加氢异构反应性能，金属负载在γ-Al₂O₃上的催化剂Pt/Al₂O₃+HZSM-2,其正十二烷转化率和异构产率均明显优于金属负载在HZSM-22分子筛上的催化剂Pt/HZSM-22+ Al₂O₃。但是将金属Pt负载在γ-Al₂O₃或直接负载在ZSM-22分子筛上并不影响单甲基异构产物的分布，其异构产物以支链靠近端部的2-甲基异构体为主。

Influence of Pt Position on the Performance of Bifunctional Catalysts for n-Dodecane Hydroisomerization

By controlling the location of Pt onγ-Al₂O₃ and ZSM-22, two kinds of composite bifunctional catalysts, referred as to Pt/ Al₂O₃+HZSM-22 and Pt/HZSM-22+ Al₂O₃, respectively, were prepared by mixing with HZSM-22 molecular sieve and Al₂O₃. The physicochemical properties of the carriers and catalysts were characterized by XRD, BET, NH₃-TPD, ICP, SEM and TEM. The performances of catalysts were evaluated by n-dodecane hydroisomerization in a micro-fixed bed reactor. Catalytic evaluation results show that the catalytic performance is affected by the loading position of Pt. Pt/Al₂O₃+HZSM-22 with Pt loading onγ-Al₂O₃ exhibits higher C₁₂ conversion and isomer yield than those of Pt/HZSM-22+ Al₂O₃ with Pt loading on HZSM-22. However, the distribution of mono-branched isomers has not been affected by the location of Pt on bothγ-Al₂O₃ and HZSM-22, with 2-Methyllundecane serving as the main isomer product.