低温等离子体协同处理含汞废气和二恶英及活性剂增效机制

The mercury and dioxins from medical waste incineration, domestic waste incineration and some metallurgical smelting flue gas, are the most difficult to be treated safely. Activated carbon adsorption is the conventional mercury, dioxins adsorption process and therefore produce secondary waste need to be disposed safely. There are serious environmental risk in the subsequent disposal process due to the reasons by the cost, technology and management. The pulsed non-thermal plasma can realize the transformation from elemental mercury into bivalent mercury or particle-associated mercury, and can decompose dioxins，simutaneously. In this research, based on the characteristics of flue gas containing mercury and dioxins, parameters of pulsed non-thermal plasma will be studied to determine its influences on the simultaneous purification effect of mercury and dioxins，as well as those of SO2 and NOx.The mechanisms of enhancement of mercury trapping and dioxins decomposition with active hydrazine additives will also be experimentally explored. The transfer and trapping machnism of mercury from the flue gas, mechanism of decomposition of dioxins, will be studied under the conditions of pulsed non-thermal plasma atmosphere with help of analysis tools of synchrotron rediation and chemical reaction dynamics.Reaction models will be set up based on the obtained reaction database to simulate and predict the influence of different operating conditions on the trapping effect of mercury and decomposition efficiency of dioxins.Through the implementation of this project, a new way will be explored to simultaneously and efficiently treat flue gas containing mercury,dioxins and other pollutants.

医疗废物、生活垃圾等废物焚烧烟气以及一些冶炼废气中汞和二恶英是最难处理的污染物，通常采用活性炭吸附并因此产生需要处理的二次废物，其后续处理因经济、技术和管理等原因难以实现安全处置，环境风险突出。脉冲低温等离子体技术（NTP）可实现不可溶单质汞向二价汞或颗粒态汞转化并能降解二恶英，有望实现低成本的废气中汞和二恶英的协同控制。本研究基于含汞和二恶英废气的特性，研究NTP的技术参数变化时对含汞和二恶英的协同处理效果，及对SO2、NOx等其他污染物的影响，并探索利用肼类添加剂强化Hg捕集和二恶英的分解效果。借助现有同步辐射及化学反应动力学分析手段，揭示在NTP条件下，废气中汞的转化和捕捉、二恶英分解机理及肼类活性剂的增效机制；建立活性添加剂作用下Hg价态转化及捕集的反应模型，以及二恶英分解反应模型，为含有汞和二恶英废气的高效协同处理提供新的途径。

医疗废物、生活垃圾等废物焚烧烟气中汞和二噁英是最难处理的污染物，脉冲低温等离子体技术（NTP）可实现单质汞的高效氧化并能降解二噁英，本研究旨在研究NTP各项参数变化对废气中汞和二噁英的协同处理效果，获得了NTP对汞和二噁英的处理效果及电源各主要技术指标（脉冲电压、脉冲频率等）对处理效果的影响，得到了处理汞、二噁英的最佳工作条件及产物分布特性；研究了脉冲低温等离子体处理含汞废气时，NO、SO2等存在的影响效果，明确了各污染物对汞氧化效果影响的变化规律；研究了脉冲低温等离子体处理含三氯苯（TCB）废气时，NO、HCl、SO2等存在的影响效果，明确了各污染物对TCB去除效果影响的变化规律；研究了脉冲低温等离子体处理含汞及二噁英的蒸气时，汞和二噁英的处理效率，获得了脉冲低温等离子体的不同参数（脉冲电压、脉冲频率等）的作用下的相互影响，获得了协同处理两类污染物的最佳工作条件。并通过chemkin软件模拟低温等离子体氧化Hg0反应的影响因素，通过分析低温等离子体单脉冲能量对于自由基浓度以及汞脱除效率的影响，获得汞污染物在反应器内变化的分布规律及脱除速率，在此基础上开展了添加剂肼分解动力学计算，并对烟气中水合肼添加比例的变化对烟气在低温等离子体反应器内氯苯脱除进行了影响研究，进一步明确了肼添加比例及单脉冲能量的变化对氯苯去除的影响机理。. 通过上述工作，建立了NTP技术及添加剂肼共同协同处置汞和二噁英的理论基础，并且探索了去除多种污染物的协同处置机理，对含汞和二噁英的汞污染源头能够有针对性的控制。本研究成果对于有效控制汞和二噁英的环境污染，促进涉汞行业重金属污染防治及废物焚烧行业烟气排放的治理、推进我国的汞及二噁英履约工作的顺利开展具有重要意义。