【作者】 王敬伟；

【导师】 王安杰；

【作者基本信息】 大连理工大学 ， 化学工程与技术， 2011， 硕士

【摘要】 世界各国都对汽柴油的质量,特别是硫含量进行严格限制。开发新型高效的加氢脱硫(HDS)催化剂用来生产超低硫燃料油,是一个十分有意义的研究课题。全硅MCM-41型介孔材料是一种优良的HDS催化剂载体,本文从MCM-41载体入手,以三甲基氯硅烷为硅烷化试剂,通过后嫁接处理法对载体MCM-41进行了硅烷化改性,通过X射线衍射、N2吸附等温线和CO吸附红外光谱等手段对改性载体骨架结构和孔性质进行了表征。以质量分数为0.8%的二苯并噻吩(DBT)的十氢萘溶液作模型化合物考察了硅烷化改性前后的MCM-41担载Pd催化剂HDS反应。结合ICP、H2化学吸附、XPS以及CO吸附红外光谱对催化剂进行表征,探讨了载体对担载的贵金属催化剂HDS反应性能的影响。以三甲基氯硅烷为硅烷化试剂对MCM-41进行硅烷化改性,原位IR结果显示,经焙烧、原位还原,载体表面仍保留硅烷基团,硅烷化改性顺利进行；XRD以及N2吸附等温线表明,改性前后MCM-41均保持了典型的全硅MCM-41六方有序介孔结构；N2吸附等温线表明硅烷化改性后MCM-41孔容、孔径和BET比表面积都有所降低。以DBT为模型化合物,考察了改性前后担载Pd催化剂的加氢脱硫反应。通过加氢脱硫活性与抗硫性效果对比,发现经硅烷化改性后担载Pd催化剂活性明显提高且能够保持良好的稳定性。长时间抗硫性测试,发现硅烷化改性后催化剂表现出良好的抗硫性；通过加氢脱硫路径选择性与产物选择性对比,可以看出硅烷化改性对催化剂的加氢性能产生很大影响。硅烷化改性主要提高了催化剂加氢反应路径的活性。同时,硅烷化改性后,催化剂表现出了较低的裂化活性。CO-IR表征结果显示,硅烷化改性对担载Pd金属的电子性质产生影响,IR谱图蓝移现象证明Pd与硅烷化载体发生强相互作用,产生了缺电子结构。Pd 3d的XPS结果同样显示有Pdδ+结构的形成。从而解释了硅烷化改性后Pd催化剂活性与抗硫性提高的原因。更多还原

【Abstract】 Environment legislations demand lower-sulfur transportation fuels all over the world. The development of novel catalyst with high efficiency to produce ultra-low sulfur diesel fuels is a meaningful topic.The Si-MCM-41 is a promising support for deep HDS catalysts, in this dissertation, silylation modification of MCM-41 was prepared using trimethylchlorosilane. XRD, N2 adsorption, CO adsorbed FTIR were performed to characterize the structure of the support. The hydrodesulfurization (HDS) performances of the supported Pd catalysts were studied using a model fuel containing 0.8 wt% DBT in decalin. ICP, H2-chemisorption, CO adsorbed FT-IR, XPS were performed to characterize the structure of the catalysts. The effects of support on the HDS performances of noble metal catalysts were discussed.Silylation modification of MCM-41 was prepared using trimethylchlorosilane, FTIR indicated that silylation process was successful. XRD and N2 adsorption indicated that the original structure of MCM-41 maintained after silylation, but the total pore volume, the pore size and the BET surface area decreased to some extent.The hydrodesulfurization (HDS) performances of the supported Pd catalysts were studied using a model fuel containing 0.8 wt% DBT in decalin. By comparing the activities and thioresistance in the HDS, the HDS activity and thioresistance were both improved by silylation modification. The long-term stability test of the supported Pd catalysts in DBT HDS indicated that the supported noble metal catalysts exhibited better thioresistance by silylation modification. By comparing the selectivities of the route and the products in the HDS, the catalysts activity was improved by silylation modification, especially the hydrogenation ability.The HYD activity was improved signally. Meanwhile, the catalysts exhibited low cracking activity by silylation modification.CO-IR indicated that the electronic properties of the Pd catalysts supported on silylated MCM-41 changed. The IR showed the frequency shifts (blue shift). The shift revealed the strong interaction between Pd and the silylated MCM-41. The XPS also proved the generation of Pdδ+. The CO-IR and XPS both indicated the improvement in activities and thioresistance originates from electron-deficient Pd.更多还原