三维有序大孔金属氧化物脱硫剂的合成及常温脱硫性能研究

发布时间：2018-01-10 07:27

本文关键词：三维有序大孔金属氧化物脱硫剂的合成及常温脱硫性能研究　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着全球化石能源的日益枯竭和环境问题的日益严峻,研究与开发高效、节能、环保的能源利用新技术已迫在眉睫。正在兴起的燃料电池(FC)技术是其中的典型代表。供氢原料气的深度脱硫是FC必须解决的关键技术环节。且随着FC应用环境与目的不同,对常低温温和条件下深度脱硫工艺的需求也越来越多。由于金属和硫之间很强的键合作用,金属氧化物化学吸收法是非常有效而普遍使用的脱硫方法。相比其它金属氧化物,氧化锌和氧化铜与硫化氢反应具有更好的热力学优势,因此在常低温条件下具有更高的脱硫精度。然而,现有常低温金属氧化物脱硫技术普遍存在硫容偏低的问题,因此硫容的提高一直是优化其常温脱硫性能的研究热点。本研究采用聚苯乙烯胶晶模板法成功制备了三维有序大孔氧化锌-氧化硅和氧化铜一氧化硅系列复合氧化物,并在固定床上对其进行了常温动态脱硫性能评价,采用X射线衍射仪(XRD)、N2吸附、傅里叶红外(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X光电子能谱(XPS)等表征手段对样品脱硫前后的物相组成、微观形貌以及织构的变化进行了分析,并且与常温脱硫机理和脱硫性能进行了关联。表征结果显示,所制备的3DOM锌硅和铜硅复合氧化物三维大孔结构整齐有序,大孔尺寸均一且长程有序度高,大孔之间有小窗口连接从而在三维空间上相互贯通。二氧化硅的掺入以及3DOM的结构效应使得复合物中的活性组分氧化锌和氧化铜被高度分散。同时,二氧化硅还对三维有序大孔结构起到一定的支撑作用。脱硫前后3DOM复合氧化物的物相组成及结构形貌发生了明显变化,其中的金属氧化物转化为相应的金属硫化物。硫化后样品的孔道急剧收缩,孔容和表面积显著下降,说明脱硫剂硫化过程是一个内部由开孔向闭孔转变的过程。因此,织构对于脱硫有着重要影响。固定床评价研究显示,3DOM金属氧化物脱硫剂常温脱硫性能明显优于常温商品脱硫剂以及无3DOM结构的金属氧化物脱硫剂,脱硫性能的大幅提升主要归功于3DOM独特的结构特征：发达而贯通的孔道、大的比表面积以及纳米尺寸晶粒。焙烧温度以及金属氧化物与二氧化硅的比例直接影响着3DOM脱硫剂的脱硫性能。此外,研究中还发现水汽对于3DOM脱硫剂的常温脱硫性能具有极大的促进作用,有水汽氛下与无水汽氛下的脱硫机理是不同的。通过对3DOM金属氧化物脱硫剂进行氨化处理,其脱硫性能明显提升,说明脱硫剂的表面性质对于其常温脱硫也起着关键作用。本实验中对3DOM金属氧化物脱硫剂的再生性能也进行了研究,结果显示,再生后样品的脱硫性能明显下降,但是相比于商品脱硫剂来说,其再生率还是相当可观。而且再生性能稳定,再生过程中孔道结构并没有发生明显的破坏和坍塌。
[Abstract]:With the increasing depletion of fossil energy and global environmental problems are becoming more and more serious, the research and development of high efficiency, energy saving, environmentally friendly energy utilization of new technology has been imminent. The emerging fuel cell (FC) technology is one of the typical representatives. Deep desulfurization hydrogen supply of raw gas is the key technology to link FC to be solved with. The FC application environment and different purposes, for deep desulfurization process at low temperature under mild conditions needs more and more. Between the metal and the sulfur strong bond, metal oxide chemical absorption method is very effective and widely used method of desulfurization. Compared with other metal oxides, the thermodynamic advantage of Zinc Oxide and copper oxide and hydrogen sulfide with reaction better, so it has higher accuracy in desulfurization under the condition of low temperature. However, the existing low temperature metal oxide desulfurization technology often exists the problem of low sulfur content, therefore The sulfur content in the increase has been a hot research to optimize the desulfurization performance at room temperature. This study used polystyrene colloidal crystal template method was employed to prepare three-dimensional ordered macroporous Zinc Oxide - silicon oxide and copper oxide silicon oxide composite oxide, the dynamic evaluation and the desulfurization performance at room temperature in a fixed bed, by using X ray diffraction instrument (XRD), N2 adsorption, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X ray photoelectron spectroscopy (XPS) phase composition characterized the samples before and after desulfurization, change of microstructure and texture were analyzed, and the correlation with ambient temperature desulfurization the mechanism and the desulfurization performance. Results show that the 3DOM Zn Si and Cu Si composite oxide three-dimensional macroporous structure prepared orderly, large pore size and uniform degree of long range order is high, a small window to connect in 3D empty hole Between each other. Through the incorporation of silica and 3DOM structure effect makes the activity group complex in the Zinc Oxide and the copper oxide is highly dispersed. At the same time, silica to a supporting role in the three-dimensional ordered macroporous structure. The 3DOM composite oxides before and after desulfurization phase composition and morphology changed obviously. One of the metal oxides into the corresponding metal sulfides. Sample pore sharp contraction after curing, the pore volume and surface area decreased significantly, indicating sulfide desulfurization process is a process of transformation from an internal hole to the obturator. Because of this, the texture has a great influence on desulfurization. Evaluation of fixed bed, desulfurization performance 3DOM metal oxide desulfurizer at ambient temperature is obviously better than that of normal goods desulfurizing agent and metal oxide desulfurization agent without 3DOM structure, greatly enhance the desulfurization performance is mainly attributed to the unique 3DOM The structural characteristics: developed and through the pore, large surface area and nano grain size. The calcination temperature and the proportion of silica and metal oxides directly affect the desulfurization performance of 3DOM desulfurizing agent. In addition, the study also found that water vapor for 3DOM desulfurization desulfurization performance at room temperature has great role in promoting, with the desulfurization mechanism water vapor in atmosphere and anhydrous steam atmosphere is different. Based on the 3DOM metal oxide desulfurizer for treatments, the desulfurization performance improved significantly, indicating the surface properties of desulfurization agent for the desulfurization at normal temperature also plays a key role in the experiment. The regeneration performance of 3DOM metal oxide desulfurizer was also investigated. Results show that the regenerated desulfurization performance of samples decreased significantly, but compared to the commodity desulfurizer, the regeneration rate is still considerable. And the regeneration performance is stable, in the regeneration process of hole There is no obvious damage and collapse in the channel structure.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TM911.4

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