三维有序大孔氧化铜基复合脱硫剂的合成及常温脱硫性能研究

发布时间：2018-03-04 20:31

  本文选题：氧化铜基复合脱硫剂　切入点：三维有序大孔　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：面对日趋严重的环境污染问题和逐步严苛的空气保护法,提高能源利用率,开发高效、绿色、节能的新技术已迫在眉睫。燃料电池是其中突出的代表。氢燃料电池的兴起使得常低温脱硫走入人们的视野。为了满足燃料电池正常运行,必须对提供燃料电池的富氢气体进行脱硫。金属氧化物吸附脱硫因脱硫精度高、工艺操作简单而被广泛采用。其中,氧化铜和氧化锌脱硫的热力学优势明显,具有很高的脱硫精度,然而常温操作条件下存在活性差、硫容低的问题。基于前期的研究结果,本研究将通过织构优化与表面改性的方法来提高氧化铜基脱硫剂对硫化氢的硫化常温脱硫性能。本研究采用胶晶模板法制得三维有序大孔铜硅及铜锌硅复合脱硫剂,并用氨气相沉积法和碱浸渍法对表面进行改性,在固定床反应器上对所制备的脱硫剂进行穿透动态评价实验。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、氮吸附(BET)、CO_2程序升温脱附(CO_2-TPD)、X光电子能谱(XPS)、X射线吸收近边结构(XANES)、热重质谱联用(TG-MS)一系列仪器进行表征,得到以下结论:SEM/TEM、XRD和氮吸附相关表征表明,具有三维有序大孔结构的脱硫剂大孔结构整齐有序,三维空间相互贯通,晶粒高度分散,比表面积大。二氧化硅的加入助于三维有序大孔骨架牢固,同时对活性金属氧化物起到分散作用。固定床穿透脱硫实验评价结果表明,三维有序大孔的特殊结构可使得铜硅复合脱硫剂的硫容提升六倍之多,突出体现了大孔在脱硫过程中的作用。硫化过程中水汽的加入对脱硫剂硫化性能起到了至关重要的作用,水膜的形成为硫化氢在金属氧化物表面的解离吸附提供了极大帮助。在相对湿度为47.6%时,脱硫剂的脱硫性能最佳,硫容达到147 mg/g。然而,由于热力学平衡所限,水汽的加入却使脱硫精度有一定降低。通过对脱硫剂表面进行氨化/碱化改性,可克服上述缺点,显著提高脱硫剂在有水气氛下的脱硫性能,使精度和硫容均有大幅提高。硫化/再生循环性能的考察研究表明,具有三维有序大孔的脱硫剂在不同温度下再生,均具有比非三维有序大孔脱硫剂更好的活性。在300℃再生后脱硫剂具有最佳的再生性能,并在硫化再生循环过程中保持高硫容。通过对铜锌硅复合脱硫剂的研究,发现铜锌硅复合脱硫剂的硫容介于锌硅复合脱硫剂和铜硅复合脱硫剂之间。在铜锌硅系复合脱硫剂中,1%的铜与锌硅复合后的脱硫剂具有最高的硫容,由此可知金属间的相互作用对其硫化性能有重要影响。
[Abstract]:In the face of increasingly serious environmental pollution problems and gradually stringent air protection laws, to improve energy efficiency, to develop efficient, green, New energy-saving technology is imminent. Fuel cell is one of the outstanding representatives. The rise of hydrogen fuel cell makes desulfurization at low temperature into people's view. In order to meet the normal operation of fuel cell, It is necessary to desulphurize the hydrogen rich body which provides fuel cell. Metal oxide adsorption desulfurization is widely used because of its high desulfurization precision and simple operation. Among them, the thermodynamic advantages of copper oxide and zinc oxide desulfurization are obvious. It has high desulphurization accuracy, however, there are some problems such as low activity and low sulfur capacity under normal operating conditions. In this study, the desulfurization performance of cupric oxide based desulfurizer on hydrogen sulfide at room temperature was improved by texture optimization and surface modification. In this study, three dimensional ordered macroporous copper-silicon and copper-zinc silicon composite desulfurizer were prepared by colloidal template method. The surface was modified by ammonia vapor deposition and alkali impregnation. The dynamic penetrability evaluation experiment of the prepared desulfurizer was carried out in a fixed bed reactor. Using scanning electron microscope (SEM), transmission electron microscope (TEM), Tem X ray diffractometer (XRDX), nitrogen adsorption (BETT) COS2, temperature programmed desorption of CO2-TPDX (X ray photoelectron spectroscopy) XPSX X ray diffraction (XPSX). The absorption near edge structure was characterized by a series of TG-MS instruments, which were characterized by thermogravimetric mass spectrometry (TG-MS). The following conclusions are obtained: XRD and nitrogen adsorption characterization show that the macroporous structure of desulfurizer with three-dimensional ordered macroporous structure is orderly, the three-dimensional space is interpenetrating, and the grains are highly dispersed. The addition of silica helps the three-dimensional ordered macroporous skeleton to be firm and disperses the active metal oxides. The experimental results of fixed bed penetration desulfurization show that, The special structure of three-dimensional ordered macroporous can increase the sulfur capacity of copper-silicon composite desulfurizer by six times, which highlights the role of macropore in the desulfurization process. The addition of water vapor plays an important role in the vulcanization performance of the desulfurizer. The formation of water film provides a great help for the dissociation and adsorption of hydrogen sulfide on the surface of metal oxides. When the relative humidity is 47.6, the desulfurization performance of the desulphurizer is the best, and the sulfur capacity is up to 147 mg / g. However, due to the thermodynamic equilibrium, The desulphurization precision is reduced by adding water vapor. The desulfurization performance of the desulfurizer in the presence of water can be greatly improved by ammoniation / alkali modification on the surface of the desulfurizer, which can overcome the above shortcomings and improve the desulfurization performance of the desulphurizer in the presence of water. The results show that the desulphurizer with three dimensional ordered macroporous is regenerated at different temperatures. After regeneration at 300 鈩，

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