【作者】 潘巧媛；

【导师】 白敏冬；

【作者基本信息】 大连海事大学 ， 环境科学， 2011， 博士

【摘要】 本论文结合国家高技术发展计划项目（863项目）“羟基自由基氧化烟气脱硫脱硝技术”（编号2008AA062317）和中华环保基金会项目“羟基自由基氧化脱除燃煤烟气二氧化硫、氮氧化物并生成酸的绿色方法”（编号CEPF200812313）,针对烟气脱硫脱硝过程中存在的二氧化硫和氮氧化物气相氧化难题,围绕大气压强电离放电规模高效制取羟基自由基以及羟基自由基氧化脱硫脱硝两大关键问题进行了研究,提出了一种大气压强电离放电制取氧活性粒子注入烟气资源化脱硫脱硝方法。利用大气压强电离放电物理手段,将水蒸气和氧气电离、离解生成O₃、O₂⁺、H₂O⁺、H₂O₂等氧活性粒子,注入烟气后经过一系列等离子体化学反应生成以羟基自由基为主体的强氧化活性物质,实现高效氧化脱除烟气中二氧化硫和氮氧化物,最终副产物为硫酸和硝酸。应用气体放电物理、等离子体化学、宏观动力学等理论和方法,阐明了氧活性粒子的形成及其注入烟气中转化为羟基自由基的等离子体化学反应机制,探讨了羟基自由基等活性粒子氧化脱除二氧化硫和氮氧化物的反应过程。根据氧活性粒子脱硫脱硝原理,设计并构建了实验系统,通过实验分析了影响二氧化硫和氮氧化物脱除的主要影响因素,初步建立了副产物回收途径,确立了羟基自由基等活性粒子氧化脱硫脱硝适宜的工艺条件。研究结果表明：大气压强电离放电制取的氧活性粒子中臭氧和正负离子浓度可达243 g/m³、2.5×10¹⁶/m³及1.7×10¹⁶/m³。注入烟气中的臭氧和离子能高效转化为羟基自由基,实现了烟气中二氧化硫和氮氧化物的单独脱除和同时脱除。单独脱除时,脱硫率和脱硝率分别可达90%和100%；同时脱除时,脱硫率和脱硝率分别达68%和100%；硫酸和硝酸回收率分别可以达68.7%和77.1%。本论文利用大气压强电离放电解决了高浓度氧活性粒子的制取难题,采用羟基自由基氧化解决了二氧化硫和氮氧化物气相氧化的难题。提出的氧活性粒子注入烟气脱硫脱硝方法具有脱除率高、不涉及湿法引入、无催化剂、无吸收剂等特点,为资源化脱硫脱硝提供了一个新方法。更多还原

【Abstract】 The work is supported by National High Technology Research and Development Program of China (No.2008AA06Z317) "SO2 and NOx Removal from Flue Gas Using Hydroxyl Radical Oxidation" and Project of China Environmental Protection Foundation (No.CEPF200812313) "A New Green Method of SO2 and NOx Removal from Flue Gas to Acid Droplets Using Hydroxyl Radicals Oxidation".With the aim of solving the problems of SO2 and NOx gas-phase oxidation in the process of desulfurization and denitrification from flue gas, this research is carried out around two key things. One is how to produce hydroxyl (·OH) radicals with high concentration and high efficiency, and the other is how to remove SO2 and NOx by radicals oxidation. In the end, these two problems will be solved, and a new gas-phase oxidation method for the removal of SO2 and NOx using strong ionization discharge at atmospheric pressure is found.Using strong electric-field ionization discharge method, water vapor and O2 are ionized, decomposed, and excited extremely into radicals, such as O3、O2-、H2O+、H2O2 and so on. The radicals can transform into·OH, once they are injected into the flue gas. The·OH radicals are generated accompanying a complicated process, which includes lots of plasma chemistry reactions. Being one of the most active radicals,·OH can oxidize SO2 and NOx into H2SO4 and HNO3 on high speed in gas-phase.Basing on the gas discharge physics, plasma chemistry, macrodynamics, the processes of radicals formation and·OH conversation are represented, and reaction mechanics of SO2 and NOx oxidizing by radicals are discussed with mathematics model helping. Experimental system of SO2 and NOx removal using radicals injection has been set up, and effects of operating conditions are discussed in detail, such as mole concentration ratio of oxygen radical to SO2/NOx, gas temperature, gas-flow rate, water vapor concentration, and so on. Moreover, the method of by-produce recycling has been investigated. At last, the optimally conditions of SO2 and NOx removal and recovery have been established.The research results show that in oxygen radicals the concentrations of ozone, positive ion and negative ion are 243 g/m3,2.5×1016/m3,1.7×1016/m3, respectively. This method not only can be applied to single desulfurization or denitrification from flue gas, with the removal rate 90% and 100%, but also the simultaneous desulfurization and denitrification, with the removal rate 68% and 100%. The recovery rates of SO2 and-NOx can reach as high as 68.7% and 77.1%, respectively.The research has solved two difficult problems of production of·OH with high concentration and SO2/NOx oxidation in gas-phase. Therefore, the method for SO2 and NOx removal from flue gas by radical injection without absorbent and catalyst additive, may open a new perspective on resourcify flue gas desulphurization and denitrification.更多还原