【作者】 吴祖良；

【导师】 骆仲泱； 高翔； 岑可法；

【作者基本信息】 浙江大学 ， 环境工程， 2006， 博士

【摘要】 随着社会经济的发展以及环保意识的提高，燃煤烟气中需控制的污染物越来越多。除了首要的SO₂和NO_x以外，汞以及碳氢化合物的控制也逐渐提上日程。然而采取组合方法对各种污染物进行逐一治理，无论从技术上还是从经济上来讲都不是合理的选择。为了降低烟气净化工艺的复杂性和投资运行费用，开发新型的烟气综合治理技术具有重要的现实意义。 本文全面阐述了自由基簇射烟气中多种污染物脱除技术，侧重于基础理论研究，并进行了放大反应器设计及应用分析。首先，电晕放电的基本物理过程、自由基簇射形成过程以及喷嘴电极结构优化被研究；接着从实验和理论研究角度，深入分析了自由基簇射SO₂和NO_x的反应特性和机理，优化了反应过程，提出了自由基簇射同时脱硫脱硝技术方案，并对该技术的大规模应用进行了经济技术性分析，为烟气污染物脱除领域提供了新的解决方案；再者，应用自由基簇射技术对有机废气的降解进行了探索，重点考察提高降解效率的关键因素和降解副产物。并且引入量子化学种的密度泛函法对多种有机物分子的键离解能进行了初步的计算分析； 在电晕放电自由基簇射实验中，发现稳定的流光电晕能够充满整个放电气隙。放电电流呈现显著的脉冲特性，而且电流随电压呈指数级增长；从喷嘴中心至喷嘴边缘的电场都大于临界电场，且电极气分子如O₂、H₂O和NH₃的键离解能都在4～5eV之间，小于自由基簇射过程产生的电子的能量，确保了自由基簇射的形成；喷嘴外径的增大能够增加电晕区域和强度，喷嘴个数的增加则提高了能量输入水平。但是由于电晕之间的屏蔽作用，过大的喷嘴外径以及过多的喷嘴个数都不利于电晕的发展。在本实验条件下，以喷嘴电极外径为3mm，喷嘴个数为14个为宜。 对于自由基簇射SO₂的脱除，单纯的氧化作用并没有起到好的脱除效果，而氨气的加入则大大提高了SO₂的转化率。此时SO₂的转化通过热化学反应、同相自由基反应以及气溶胶表面的异相自由基反应，这3种途径对SO₂转化的贡献率分别为65％、20％和15％；而对于NO_x的脱除，氧化作用是决定性的，60％以上的NO被氧化成了NO₂。烟速的成倍增加减少了烟气在电晕区和非电晕区内的更多还原

【Abstract】 With the development of economy and the improvement of environmental protection awareness, more pollutants need be controlled from coal-combustion flue gas. In addition to the primary SO₂ and NO_X, the controls of mercury and hydrocarbon are gradually proposed the program. However, whether from the technical or economical viewpoint, it isn’t reasonable that all kinds of pollutants are controlled one by one using combinative methods. In order to reduce the craft complexity and the investment and running cost, it has important realistic signification to develop an integrated control technology for flue gas.The radical shower multi-pollutants removal technology was completely expatiated in this paper. The basic theory study was emphasized and the design and application of amplificatory reactor were analyzed. Firstly, the basically physical process of corona discharge, the forming process of radical shower and the configuration optimization of nozzle electrode was studied. Secondly, the reactive characteristics and mechanism of radical shower SO₂ and NO_X removal was deeply investigated from the experiment and theory. The simultaneous removal of SO₂ and NO_x with radical shower technology was put forward on the basis of optimizing the reactive process and its economical and technical analysis for the large-scale application was done, which provides a new approach in the flue gas pollutant removal field. Finally, the organic exhaust gas decomposition using the radical shower technology was explored. The key factors improving decomposition rate and the decomposition by-products were emphasized. The bond dissociation energies of various organic compounds were calculated using the DFT method in the quantum chemistry.It is found in the corona discharge radical shower experiment that the stable streamer corona can be full of the whole discharge space. The discharge current increases exponentially and presents obvious pulsed characteristics with the increasing discharge voltage. The electric field from nozzle center to nozzle edge is更多还原