铝改性介孔二氧化硅泡沫载体材料合成及其DBT加氢脱硫性能（英文）

发布时间：2018-05-06 16:03

本文选题：铝改性介孔二氧化硅泡沫 + 硅铝比　；参考：《催化学报》2017年08期

【摘要】：介孔二氧化硅泡沫(MCFs)材料具有超大的三维球形孔结构、超大孔容(1.0 2.4 cm~3/g)、高比表面(1000 m~2/g)、孔径可调范围较广(24 50 nm)且球形孔道之间通过窗口(9 22 nm)联结,因此具有优良的传质性能,能够促进加氢脱硫反应.但是,与传统的微孔分子筛相比,该纯硅类介孔材料酸性较弱,不利于一些酸催化反应;因此,对纯硅材料进行金属改性以增加其酸性,从而促进催化剂的催化活性.而一般对纯硅类介孔材料采用Al,Ti,Zr等金属,铝改性主要是为纯硅载体提供酸性,而钛锆改性则是为了调变活性金属以及促进金属的分散,从而提高催化剂的加氢脱硫活性.因此,我们主要采用后改性方法,以P123为微乳液体系中的表面活性剂,TEOS为硅源,TMB为扩孔剂,异丙醇铝为铝源,成功合成了一系列Si/Al比不同的介孔二氧化硅泡沫材料.通过改变异丙醇铝的加入量,成功合成了系列Si/Al比(x)的NiMo/Al-MCFs(x)(x=10,20,30,40和50)催化剂.对所合成的载体及相应的催化剂通过SAXS,N_2吸附脱附,SEM,Py-FTIR,UV-Vis,H_2-TPR,NH3-TPD,HRTEM,Raman及~(27)Al MAS NMR等表征手段进行分析,并在高压加氢微反装置上对相应的NiMo负载型催化剂进行DBT HDS活性评价,系统分析了不同硅铝比对催化剂DBT HDS反应活性的影响.SAXS和SEM表征结果表明,Al后改性并没有破坏载体材料的结构;~(27)Al MAS NMR表征结果表明,后改性法能成功把Al掺杂进纯硅材料的骨架中.催化剂UV-Vis和Raman表征结果表明,当Si/Al比为20时,NiMo/Al-MCFs(20)催化剂Mo物种的带隙能量最大,且氧化钼的平均粒径较小,Mo物种在该催化剂中的分散度较好;H_2-TPR分析结果表明,NiMo/Al-MCFs(20)催化剂还原温度较低,最易还原.Py-FTIR结果表明,随着Al加入量的增大,其酸性逐渐增大,当Si/Al比为20时酸性达到最大,继续增加Al的加入量,其酸性不再增加;此外,NiMo/Al-MCFs(20)的硫化度最高,且其MoS_2的堆垛层数较低.负载活性金属后制备了NiM o/Al-MCFs(x)催化剂,将其应用于DBT加氢脱硫反应,并与传统NiM o/γ-Al_2O_3催化剂加氢脱硫反应活性作对比.研究发现,所制备的NiMo/Al-MCFs(x)系列催化剂由于具有较大孔径、比表面积及孔容和较强的酸性,因而其DBT HDS活性明显高于传统的工业NiMo/g-Al_2O_3催化剂,且催化剂活性在硅铝比达到20时最大,最高可达96%,因此它作为加氢脱硫催化剂载体具有很大的应用前景.
[Abstract]:The mesoporous silica foam MCFs has a very large three-dimensional spherical pore structure, a very large pore volume of 1.0 ~ 2.4 cm ~ (2) cm ~ (-1) / g ~ (-1), a high specific surface area of 1 000 m ~ (2) / g ~ (-1), a wide adjustable aperture range of 24 ~ 50 nm) and a connection between the spherical channels through a window of 9 ~ 22 nm), so it has excellent mass transfer performance. It can promote the hydrodesulfurization reaction. However, compared with the traditional microporous molecular sieves, the pure silica mesoporous materials are less acidic, which is not conducive to some acid-catalyzed reactions. Therefore, the pure silicon materials are modified by metal to increase their acidity, thus promoting the catalytic activity of the catalysts. Aluminum is mainly used to provide acid for pure silicon carrier, while titanium zirconium is used to modify the active metal and promote the dispersion of metal, so as to improve the hydrodesulfurization activity of the catalyst. Therefore, a series of mesoporous silica foams with different Si/Al ratios were successfully synthesized by post-modification method, using P123 as the surfactant in the microemulsion system and TMB as the pore expander and aluminum isopropanol as the aluminum source. By changing the amount of aluminum isopropanol, a series of NiMo / Al-MCFS (10 / 20) 30 ~ (40) and 50) catalysts have been successfully synthesized. The synthesized supports and their corresponding catalysts were characterized by SAXS- Py-FTIRU UV-VisH- H2-TPR-NH3-TPD-HRTEMU MAS NMR and the DBT HDS activity of the corresponding NiMo supported catalysts was evaluated on a high pressure hydrogenation microreactor. The effects of Si / Al ratio on the activity of DBT HDS reaction were systematically analyzed. The results of SAXS and SEM characterization showed that the modified catalyst did not destroy the structure of the support material, and the results of MAS NMR characterization showed that the modified catalyst did not destroy the structure of the support material. After modification, Al can be successfully doped into the framework of pure silicon. The results of UV-Vis and Raman characterization showed that the band gap energy of Mo species was the highest when the Si/Al ratio was 20:00. The average particle size of molybdenum oxide is smaller and the dispersion of Mo species in the catalyst is better. The results of H2-TPR analysis show that the reduction temperature of NiMo- / Al-MCFsCF-20) catalyst is lower, and the results of .Py-FTIR show that the acidity increases with the increase of Al content. When the Si/Al ratio reaches the maximum at 20:00, the acidity does not increase when the addition of Al continues to increase, in addition, the sulfidation of NiMo-Al / MCFsCF-20) is the highest, and the number of stacking layers of MoS_2 is lower. The NiM o / Al-MCFS X) catalyst was prepared after the active metal was supported. The catalyst was applied to the hydrodesulfurization of DBT and compared with that of the traditional NiM o / 纬 -Al _ 2O _ 3 catalyst. It is found that the DBT HDS activity of NiMoAl-MCFsX) series catalysts is obviously higher than that of traditional commercial NiMo/g-Al_2O_3 catalysts because of its large pore size, specific surface area, pore volume and strong acidity, and the activity of the catalysts reaches 20:00 at the ratio of Si / Al. The maximum is 96, so it has great application prospect as the support of hydrodesulfurization catalyst.
【作者单位】：中国石油天然气股份有限公司石油化工研究院;中国石油化工股份有限公司抚顺石油化工研究院;中国石油大学国家重油加工重点实验室北京;
【基金】：supported by National Natural Science Foundation of China (21276277,U1463207) CNOOC Project CNPC major project the Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology (2015K003)~~
【分类号】：O643.36

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