低温选择加氢脱硫醚催化剂NiMoZn/Al2O3中Zn的作用

以Al₂O₃作为载体,采用等体积浸渍法制备了多种不同的金属氧化物催化剂,考察其低温选择加氢脱硫醚活性。以1-戊烯和叔丁基甲基硫醚的环己烷模型化合物为反应原料,考察助剂的添加对NiMo/Al₂O₃催化剂性能的影响,并筛选出选择加氢脱硫活性最优的催化剂;接着以FCC全馏分汽油进行150h的长周期实验考察最优催化剂的性能;通过SEM、XRD、H₂-TPR、C₄H₄S-TPD、硫碳分析对催化剂进行了表征。实验结果表明:经过适当组合的三组分催化剂的选择加氢脱硫醚的性能有所改变,其中以NiMoZn/Al₂O₃催化剂的选择加氢脱硫醚性能最好,并在长周期试验中表现出很好的活性和稳定性。表征结果证实Zn的加入起到了分相作用,促进NiO向表面迁移;降低活性组分与载体间的强相互作用,有利于组分的还原;适宜的Zn含量有利于催化剂表面的活性相均匀分布;Zn促进催化剂对硫化物的吸附。

Study on the effect of Zn on selective hydrodesulfurization catalyst NiMoZn/Al2O3 fortert-butyl methyl sulfide at low temperature

Metal oxide catalysts supported on Al₂O₃ for selective hydrodesulfurization of tert-butyl methyl sulfide at low temperature were prepared by co-impregnation. The cyclohexane model compounds containing 1-pentene and tert-butyl methyl sulfide were used as raw material for reaction. The catalytic performance of three-component catalysts was investigated to choose the optimal catalyst which was then reacted in the full-range FCC gasoline during a 150h long-period experiment. The results showed that adding the third elements changed the catalytic performance; NiMoZn/Al₂O₃ catalyst was the best, while the NiMoZn/Al₂O₃ catalyst showed high activity and stability in FCC gasoline. Effect of Zn was investigated by SEM, XRD, H₂-TPR and the analysis of S, C content. Adding Zn promotes the surface migration of NiO, and reduces the strong interaction between support and active component, which can facilitate the reduction. The suitable Zn content promotes the distribution of active component on the surface of catalyst.