负载型钒基催化剂上丙烷氧化脱氢制丙烯的研究

发布时间：2018-05-10 14:33

  本文选题：丙烷氧化脱氢 + β分子筛　； 参考：《北京服装学院》2017年硕士论文

【摘要】：丙烯是石油化工基础原料之一,主要用于生产丙烯酸、丙烯醛、醇、酸、酐及腈等。随着需求量的快速增长,传统技术生产的丙烯难以满足实际需求。虽然丙烷直接脱氢制丙烯已经实现工业化,但此反应是吸热反应,生产工艺需要高温,耗费大量能量,而丙烷氧化脱氢反应是在较低温度下的放热反应,可以大大降低能耗。所以,开发高选择性、高活性的丙烷氧化脱氢催化剂具有重要意义。本文利用浸渍法制备了V/β和V/γ-Al2O3催化剂,为了寻求更高选择性的丙烷氧化脱氢制丙烯的催化剂,对上述催化活性较好的催化剂进行改性,制备了不同镁含量的V-Mg/β和V-Mg/γ-Al2O3催化剂。利用XRD、BET、H2-TPR、NH3-TPD、UV-Vis DRS和FT-IR等手段对催化剂进行分析,并考察它们在丙烷氧化脱氢制丙烯反应中的催化性能。借助原位红外光谱仪研究丙烷和丙烯在催化剂上的吸附以及在程序升温过程中的变化,最后借用化学模拟软件模拟丙烷和丙烯在分子筛上的吸附过程。实验结果表明:1.反应温度500℃下,V负载量为8wt%的8V/β和8wt%的8V/γ-Al2O3的催化剂的活性较好。2.Mg的含量为4wt%的8V4Mg/β催化剂的活性较好,反应温度500℃下,丙烯选择性为71.2%,丙烷转化率为17.2%。3.利用原位红外光谱仪研究在50、500℃下,丙烷分别在β分子筛、8V/β和8V4Mg/β催剂上吸附的过程,同时研究丙烷和丙烯分别在8V/β、8V/γ-Al2O3、8V4Mg/β和8V4Mg/γ-Al2O3催化剂的程序升温过程。原位红外光谱表明,活性组分钒的加入,有利于催化剂对丙烷的吸附,碱金属Mg有利于丙烯的选择性。4.分子筛的大孔更有利丙烷和丙烯的吸附,丙烯的吸附量比丙烷大,丙烷自扩散系数均随着吸附量的增加而减少,V2O5与丙烷、丙烷+氧气反应时,出现不同反应过程,但都有丙烯的生成。
[Abstract]:Propylene is one of the basic petrochemical raw materials, mainly used in the production of acrylic acid, acrolein, alcohol, acid, anhydride and nitrile. With the rapid growth of demand, propene produced by traditional technology is difficult to meet the actual demand. Although the direct dehydrogenation of propane to propylene has been industrialized, the reaction is an endothermic reaction, which requires high temperature and consumes a lot of energy. However, the oxidative dehydrogenation of propane is an exothermic reaction at a lower temperature, which can greatly reduce the energy consumption. Therefore, it is of great significance to develop highly selective and highly active catalysts for oxidative dehydrogenation of propane. In this paper, V / 尾 and V / 纬 -Al _ 2O _ 3 catalysts were prepared by impregnation method. In order to find more selective catalysts for oxidative dehydrogenation of propane to propylene, the catalysts with better catalytic activity were modified, and V-Mg/ 尾 and V-Mg/ 纬 -Al _ 2O _ 3 catalysts with different magnesium contents were prepared. The catalysts were analyzed by means of DRS and FT-IR, and their catalytic properties in the oxidative dehydrogenation of propane to propylene were investigated. The adsorption of propane and propylene on the catalyst and the changes in temperature programmed process were studied by in situ infrared spectrometer. Finally, the adsorption process of propane and propylene on molecular sieve was simulated by chemical simulation software. The result of the experiment shows that 1: 1. At 500 鈩，

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