镁硅分子筛的合成及其催化性能研究

发布时间：2018-01-16 02:36

本文关键词：镁硅分子筛的合成及其催化性能研究　出处：《东北石油大学》2016年硕士论文　论文类型：学位论文

更多相关文章： MCM-48 镁硅分子筛 Ni 正庚烷 异构化

【摘要】：在石油炼制工业中,生产环保型燃料油和优质润滑油都与临氢异构化反应有关。而正庚烷异构化在提高汽油辛烷值过程中发挥着重要作用。同时具有加氢-脱氢活性又具有酸活性的双功能催化剂为近年来正庚烷异构化的主要催化剂。MCM-48介孔分子筛的三维螺旋孔道结构有利于物料的传输,较高的比表面积有利于活性组分的分散。但纯硅MCM-48介孔分子筛催化活性低,引入活性组分合成具有稳定催化活性的介孔材料具有广阔的应用前景。因此本文以镁改性MCM-48介孔分子筛为载体,制备负载型双金属催化剂,并通过XRD、N2吸附-脱附、FT-IR、SEM、NH3-TPD等表征手段考察金属Mg的引入对催化剂结构、形貌、酸性及稳定性的影响,同时以正庚烷异构化反应为探针考察Ni/Mg-MCM-48的催化性能,主要内容如下:1.以水热合成法合成原位掺杂镁的MCM-48介孔分子筛,并考察了不同制备条件对镁改性MCM-48介孔分子筛结构的影响,结果表明当Mg与Si摩尔比为0.02时,在110o C下晶化72 h,在550o C下焙烧5h,所得到的Mg-MCM-48介孔分子筛有序性最强。2.以金属Ni为活性组分,镁改性MCM-48为载体,采用浸渍法制备Ni/Mg-MCM-48催化剂,并考察了制备条件、还原条件和反应条件对Mg-MCM-48催化剂催化性能的影响,结果表明在制备条件为(3%Ni,焙烧温度=400o C,焙烧时间=4h),还原条件为(还原温度=400o C,还原时间=4h),反应条件为(反应温度=250o C,WHSV=6.8h-1,氢气流速=40ml/min)时催化剂催化性能较好,转化率和选择性分别达到44.7%和90.3%。
[Abstract]:In the oil refining industry. The production of environment-friendly fuel oil and high quality lubricating oil are all related to hydroisomerization. The n-heptane isomerization plays an important role in increasing the octane number of gasoline. It also has hydrogenation dehydrogenation activity and acid activity. Bifunctional catalyst is the main catalyst for n-heptane isomerization in recent years. MCM-48 mesoporous molecular sieve three-dimensional spiral pore structure is conducive to the transport of materials. Higher specific surface area is beneficial to the dispersion of active components, but the catalytic activity of pure silicon MCM-48 mesoporous molecular sieve is low. The synthesis of mesoporous materials with stable catalytic activity by introducing active components has broad application prospects. Therefore, supported bimetallic catalysts are prepared by using magnesium modified MCM-48 mesoporous molecular sieve as the carrier. The influence of the introduction of mg on the structure, morphology, acidity and stability of the catalyst was investigated by means of XRDN _ 2 adsorption-desorption and FT-IRN / SEMN NH _ 3-TPD. At the same time, the catalytic properties of Ni/Mg-MCM-48 were investigated with n-heptane isomerization as probe. The main contents were as follows: 1. In situ MgO-doped MCM-48 mesoporous molecular sieve was synthesized by hydrothermal synthesis. The effects of different preparation conditions on the structure of MCM-48 mesoporous molecular sieve modified by magnesium were investigated. The results showed that when the molar ratio of mg to Si was 0.02, the crystallization time was 72 h at 110o C. When calcined at 550 o C for 5 h, the ordered properties of Mg-MCM-48 mesoporous molecular sieve were strongest. 2. The metal Ni was used as active component and magnesium modified MCM-48 as carrier. Ni/Mg-MCM-48 catalysts were prepared by impregnation method. The effects of preparation conditions, reduction conditions and reaction conditions on the catalytic performance of Mg-MCM-48 catalysts were investigated. The results show that the preparation conditions are as follows: Ni3, calcination temperature 400o C, roasting time 4hs, and reduction conditions: reduction temperature 400o C, reduction time 4h. The catalytic performance of the catalyst is better when the reaction temperature is 250o / h ~ (-1) and the flow rate of hydrogen is 40 ml / min. The conversion and selectivity reached 44.7% and 90.3 respectively.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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