甲烷重整制合成气催化反应研究

发布时间：2018-04-17 03:11

本文选题：氧化铝 + 干气重整　；参考：《南京大学》2015年硕士论文

【摘要】：甲烷二氧化碳重整或甲烷水二氧化碳双重整制合成气,进而通过合成气转化成多种重要化学品是天然气有效利用的重要途径。这一反应目前还没有应用到实际工业中的重要原因就是仍没有研制出一种高稳定、高活性、价格低廉的催化剂。本论文主要围绕此课题展开工作,以传统催化剂反应理论为基础,通过合理设计、合成针对甲烷二氧化碳重整或甲烷水二氧化碳双重整反应的高效催化剂,提出了一条获得在苛刻反应条件下保持高活性、高稳定性催化剂的可行路线,为该系列反应真正实现工业化打下一定基础。主要工作如下：1.针对催化剂活性中心的烧结以及活性中心及载体上的积碳导致催化剂失活的这一原因,本工作通过详细分析其中的物理化学机制,采用相应解决办法,各个击破。首先,制备出CuNi合金纳米颗粒并将其负载在y-Al_2O_3载体上一克制催化剂活性中心上的积碳。实验结果证明,此方法确实可以有效抑制反应过程中活性中心因为积碳而导致的不稳定,催化剂能够维持长时间的高活性;其次,预先在γ-Al_2O_3载体表面沉积一层氧化锆以克制载体上的积碳,同时减弱CuNi合金纳米颗粒与载体的相互作用,防止合金中铜组分在高温下与氧化铝载体反应,以达到稳定合金结构的目的;最后,在沉积CuNi合金纳米颗粒之后,再沉积一层氧化锆,以有限包裹CuNi合金颗粒防止活性颗粒达到烧结长大。实验结果证明,通过上述方法得到的催化剂,在甲烷二氧化碳干气重整的条件下,具有长期运行的高活性和高稳定性。2.实际反应中,由于逆水汽变换反应通道的存在,甲烷二氧化碳干气重整得到的合成气比例组成中,H_2/CO1,这种组成将限制后续工业应用的范围。通过往反应体系中加入一定比例的水,即实现双重整反应,可以实现对合成气组成的控制。在前述工作的基础上,本论文进一步考察了经过两次氧化锆修饰的CuNi合金催化剂在甲烷水二氧化碳双重整条件下的催化反应性能,证实这样的催化剂,即使在有水的高温反应条件下,也能维持相当时间的高活性和高稳定性。通过多种谱学手段表征了催化剂的结构以及在催化反应中的变化过程,为进一步掌握该类型催化剂的实际应用提供了宝贵的基础研究成果。
[Abstract]:Methane carbon dioxide reforming or methane water carbon dioxide dual integration to syngas, and then converted to a variety of important chemicals through syngas is an important way for the effective use of natural gas.The main reason why this reaction has not been applied to practical industry is that a catalyst with high stability, high activity and low price has not been developed.Based on the theory of traditional catalyst reaction, this thesis mainly focuses on the synthesis of high efficiency catalyst for methane carbon dioxide reforming or methane water carbon dioxide dual integral reaction through reasonable design.A feasible way to obtain the catalyst with high activity and high stability under harsh reaction conditions was put forward, which laid a foundation for the industrialization of the series of reactions.The main work is as follows: 1.In view of the reason that the sintering of the active center of the catalyst and the carbon deposition on the active center and the carrier lead to the deactivation of the catalyst, the physical and chemical mechanism of the catalyst is analyzed in detail, and the corresponding solutions are adopted.Firstly, the CuNi alloy nanoparticles were prepared and loaded on the y-Al_2O_3 support to restrain the carbon deposition on the active center of the catalyst.The experimental results show that this method can effectively suppress the instability of the active sites caused by carbon deposition in the reaction process, and the catalyst can maintain high activity for a long time.A layer of zirconia was deposited on the surface of 纬 -Al _ 2O _ 3 carrier in advance to restrain carbon deposition on the carrier, and at the same time, the interaction between the CuNi alloy nanoparticles and the carrier was attenuated so as to prevent the copper component in the alloy from reacting with the alumina carrier at high temperature.Finally, after depositing CuNi alloy nanoparticles, a layer of zirconia was deposited to prevent the active particles from sinter and grow.The experimental results show that the catalyst obtained by the above method has high activity and stability for a long time under the condition of methane carbon dioxide dry gas reforming.In the actual reaction, due to the existence of the reverse water vapor shift reaction channel, the proportion of synthetic gas obtained from the methane carbon dioxide dry gas reforming is H _ 2 / CO _ 1, which will limit the scope of subsequent industrial application.The composition of syngas can be controlled by adding a certain proportion of water to the reaction system.On the basis of the above work, the catalytic properties of CuNi alloy catalysts modified by zirconia were further investigated under the condition of methane, water and carbon dioxide.Even under the condition of high temperature reaction with water, high activity and high stability can be maintained for a certain period of time.The structure of the catalyst and the changing process in the catalytic reaction were characterized by various spectroscopic methods, which provided valuable basic research results for further understanding the practical application of this type of catalyst.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE665.3

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