【作者】 薄拯；

【导师】 岑可法； 严建华； 池涌；

【作者基本信息】 浙江大学 ， 工程热物理， 2008， 博士

【摘要】 有机废气是一种排放量大、污染面广且对人体和环境都具有严重危害作用的气态污染物。它广泛来源于油漆、涂料、润滑油等化学制品的涂层作业,其主要成分为挥发性有机化合物（Volatile Organic Compounds,VOCs）。当前存在的VOCs处理技术还不能在经济性和技术性方面同时满足工业排放有机废气的治理需求。因此,在完善现有工艺的同时,进一步开发出新型处理工艺具有其必要性和市场价值。基于此背景,本文将滑动弧放电低温等离子体技术应用于环境保护和废气治理领域,通过理论和实验研究建立起可指导工业应用的理论体系,通过装置结构改进使之适合工业应用的要求,并通过示范性工程应用对其工业应用前景作技术经济性分析和评估。本文还针对甲烷这种特殊的VOCs,开展了滑动弧放电等离子体辅助甲烷/二氧化碳重整制取合成气的可行性分析工作。论文的第一章是对论文背景及技术关键点相关知识的文献综述。首先,介绍了VOCs的定义、来源、危害和现有处理技术,以及低温等离子体技术的概念、发生方式和在气态污染物治理方面的应用情况。然后,重点介绍了滑动弧放电现象的物理特征、等离子体特性、研究现状,以及和其它低温等离子体发生方式的比较。在此章节中,还包括了对全文系统和框架的介绍。论文的第二章是滑动弧放电等离子体物理特性研究。首先,针对实验台规模交流滑动弧放电反应器进行放电电参数检测、放电电弧移动特性检测,以及气体流场模拟计算。然后,通过实验结果和理论热动力平衡计算结果之间的对比,并结合等离子体区域光谱分析的结果,对滑动弧放电过程非平衡特性刺激化学反应的能力进行了分析。在此章节中,还包括了对本论文所采用的主要分析测试仪器和软件的介绍说明。论文的第三章是滑动弧放电等离子体处理VOCs的初步研究。首先研究了滑动弧放电在降解过程中对VOCs浓度和流量的适应性。然后以正已烷(n-C₆H₁₄)为代表性VOCs,研究了放电过程参数,如放电电压、VOCs初始浓度、背景气体成分、背景气体氧气浓度等,对VOCs降解率的影响。基于上述实验结果,初步分析了滑动弧放电降解VOCs的过程和机理。最后,通过分析电极间距以及电极喉部高度对电弧移动特性和VOCs降解性能的影响,对滑动弧放电反应器的结构开展了研究工作。论文的第四章是滑动弧放电等离子体处理VOCs机理研究。首先,以研究背景气体相对湿度和氧气浓度对VOCs降解性能的影响作为切入口,研究了背景气体的氧气浓度和相对湿度对滑动弧放电特性的影响。然后,针对四氯化碳（CCl₄）,正已烷(n-C₆H₁₄)和甲苯（C₇H₈）三种不同结构的典型VOCs,通过实验研究,分析了背景相对湿度和氧气浓度对VOCs降解产物和降解率的影响。在上述实验结果的基础上,针对不同VOCs化学结构,分析了高能电子和活性基团对VOCs降解过程所起作用的重要性差异,实现探索滑动弧放电低温等离子体降解VOCs机理的目的,对提高降解过程选择性提供理论指导。论文的第五章对滑动弧放电处理挥发性有机化合物过程中二氧化氮生成和抑制途径进行了研究.在分析滑动弧放电过程二氧化氮的生成机理的基础上,研究了VOCs化学结构、供给电压、反应器结构等参数对二氧化氮生成的影响。最后,探讨了放电过程二氧化氮生成的抑制途径。论文的第六章是滑动弧放电装置结构改进及工业应用设计。首先,通过实验研究和流体数值计算对传统滑动弧放电装置的放大进行了研究和分析。然后,受等离子体区域光谱分析结果的启发,提出了一种改进型滑动弧放电装置,并针对四氯化碳（CCl₄）,正已烷(n-C₆H₁₄)和甲苯（C₇H₈）三种典型VOCs的降解性能进行研究和分析。通过和多电极滑动弧放电装置处理效果的对比,对该装置做出技术性和经济性评估。基于此改进思路,提出多电极改进型滑动弧放电装置的设计方案。最后,对改进型滑动弧放电反应器及活性炭吸附-滑动弧联合技术的工业应用进行了技术经济性分析。论文的第七章是滑动弧放电甲烷/二氧化碳重整（Dry Methane Reforming,DMR）制取合成气的可行性分析。本章主要研究了甲烷/二氧化碳摩尔比对DMR过程的影响,考察对象包括反应物（甲烷和二氧化碳）转化率、合成气成分、主要放电产物的生成率和选择率、反应物单位转化量能耗和生成物单位生成量能耗等。通过实验结果和理论热平衡计算结果的比较,对滑动弧放电刺激DMR过程中的低温等离子体作用进行验证和分析。最后,通过和传统DMR过程以及其他等离子体放电DMR过程的比较,对滑动弧放电DMR过程作经济性评估,并分析其进一步应用的潜力。论文的第八章是全文总结及工作展望。主要包括对全文结论的总结归纳,论文创新点的提炼,以及对未来需要进一步加强或开展的研究工作的展望。更多还原

【Abstract】 Organic waste gas is particularly burdensome for both the natural environment and human health. It is widely emitted from the processes containing the uses of paint, dope, and lube, etc. The main components of this type of gaseous pollutants are so-called the volatile organic compounds （VOCs）. Currently, the applications of conventional technologies for VOCs removal process can’t simultaneously meet the economic and technical requirements owing to their own disadvantages, so the development of innovative VOCs removal technology is essentially necessary. In this dissertation the gliding arc discharge non-thermal plasma （NTP） is applied into the region of environmental protection: a theoretical system which can be used for the guidance of industrial application is built based on both the theoretical analysis and experimental researches; the device structure is developed to fit for the practical application; and the technical and economic assessments are performed based on the results of a demo project. Furthermore, the explorative work on the methane reforming with carbon dioxide is also carried out.Chapter one is the background review, mainly including the definitions of VOCs, the sources of VOCs, the harm of VOCs, the conventional VOCs removal technologies, the concept of NTP, the various styles of NTP sources, and the application of NTP in the gaseous emission control areas, etc. The gliding arc discharge plasma has been paid particular attentions, mainly focusing on the operation phenomenon, the features of plasma region, the state-of-art of current application, as well as the comparison of which with other NTP sources. In this chapter, the framework and the structure of this dissertation are also introduced.Chapter two is on the researches on the physical characteristics of gliding arc discharge plasma. An experimental scale AC gliding arc discharge reactor is used for the discharge parameters detection, the arc movement analysis, and the gas field and velocity field simulation calculation. Then the non-thermal property of gliding arc evolution is analyzed with the comparison between experimental results and thermodynamic equilibrium calculation data, and also based on the plasma region spectral analysis results.Chapter three is on the preliminary researches about the VOCs decomposition with gliding arc discharge. Firstly, the VOCs decomposition performances of gliding arc discharge are investigated, with the targets as single compound VOCs, dilute VOCs mixtures, and concentrated VOCs mixtures, respectively. Then the influences of discharge parameters, i.e. supply voltage, VOCs initial concentration, background gas component, and the background oxygen concentration, etc. on the VOCs decomposition performance are investigated, with hexane (n-C₆H₁₄) is chosen as the typical VOCs. Based on the above, the mechanism of gliding arc discharge assisted VOCs decomposition is preliminarily discussed and analyzed. Finally, the gliding arc discharge reactor structure is analyzed based on the researches of the influences of electrodes gap and throat height on the VOCs decomposition efficiency and specific energy consumption, etc.Chapter four is on the mechanism of VOCs decomposition in gliding arc discharge plasma atmosphere. The investigation on the influences of background relative humidity and oxygen concentration on VOCs decomposition is chosen as the entry point. Firstly, the influences of background relative humidity and oxygen concentration on the gliding arc discharge characteristics are investigated, and then the researches on the effects of background relative humidity and oxygen concentration on three different types of VOCs, i.e. tetrachloromethane （CCl₄）, n-butane (n-C₄H₁₀) and toluene （C₇H₈）, are carried out. Based on above experimental results, the dominant decomposition channels and species under gliding arc non-thermal plasma conditions for different VOCs structures are discussed.Chapter five is on the nitrogen dioxide formation in the gliding arc discharge assisted VOCs decomposition processes. NO₂ formation in dry air gliding arc discharge is mechanistically discussed based on the thermodynamic equilibrium calculation and plasma region spectra analysis. Then the influences of VOCs chemical structure, supply voltage, background humidity, and reactor geometry on NO₂ formation are experimentally investigated. The pathways of NO₂ formation inhibition are discussed based on the above.Chapter six is on the gliding arc discharge device development and the design for industrial application. The scale-up analysis on traditional gliding arc facility is studied based on the laboratory experiments and numerical simulation. An innovative developed gliding arc discharge reactor based on a modified gas feed system is proposed. The performances of developed gliding arc discharge reactor in the decomposition of VOCs with relative high gas flow rate, including the decomposition efficiency, the specific energy consumption, and the decomposition by-products, are investigated, with tetrachloromethane （CCl₄）, n-butane (n-C₄H₁₀) and toluene （C₇H₈） are chosen as the typical VOCs. The economic and technical assessments are performed with the comparison with multi-electrode gliding arc discharge device, and the design of multi-electrode developed gliding arc discharge device is proposed. At the end, the economic analysis on the activated carbon-gliding arc technology for the treatment of industrial VOCs emission control is also carried out.Chapter seven is on the gliding arc gas discharge assisted dry methane reforming （DMR）. The influences of feed gas proportion on the reagents conversion and main by-product distribution are investigated in different supply voltage conditions. Based on the present investigation, the performance of the plasma assisted DMR process of gliding arc discharge facility is assessed by the comparison between experimental result and theoretical thermodynamic equilibrium calculation data. Finally, the economic assessment on the gliding arc assisted DMR process is carried out via the comparison with traditional DMR process and other plasma assisted DMR processes, based on which the potential of the application of gliding arc discharge in the assistance of DMR process is also analyzed.Chapter eight mainly includes the conclusions and the innovative point of this dissertation, and the prospect of future work.更多还原