Nitrogen dioxide formation in the gliding arc discharge-assisted decomposition of volatile organic compounds
Nitrogen dioxide formation in the gliding arc discharge-assisted decomposition of volatile organic compounds
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DOI：
10.1016/j.jhazmat.2008.12.030
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发表时间：
2009-07-30
影响因子：
13.6
通讯作者：
Cen, Kefa
中科院分区：
文献类型：
--
作者：
Bo, Zheng;Yan, Jianhua;Cen, Kefa
为了将滑动弧光放电(GAD)等离子体处理应用于挥发性有机化合物(VOCs)的排放控制，需要解决作为有害副产品的NO2的形成问题。实验和热力学平衡计算的出水温度和产物浓度的对比结果表明，干燥空气中NO2的生成完全脱离热力学平衡。同时，在干燥空气GAD等离子体区检测到明显的NO(A(2)Sigma(+))和N-2(+)(B-2 Sigma(+)(U))是主要的反应物种。这些结果表明，在GAD系统中，热(或Zeldovich)NOx的生成机制并不明显，而等离子体区域的能级和电子密度将严重影响NO2的生成。原料气中500ppm的VOCs对NO2的生成影响有限，其大小顺序为芳香烃(C6H6和C7H8)和直链烃(C4H10和C6H14)和卤代烃(CCl4)。考察了VOCs化学结构、供电电压、进气湿度和反应器几何形状对NO2生成的影响，结果与上述机理分析相吻合。在此基础上，探讨了GAD辅助VOCs分解过程中抑制NO2生成的可能途径。(C)2008爱思唯尔B.V.保留所有权利。
To apply gliding arc discharge (GAD) plasma processing to volatile organic compounds (VOCs) emission control, the formation of NO2 as an undesired byproduct needs to be addressed. Comparative results of effluent temperature and product concentrations between experiment and thermodynamic equilibrium calculation show that the NO2 formation in dry air GAD is totally out of thermodynamic equilibrium. Meanwhile, obvious NO (A(2)Sigma(+)) and N-2(+) (B-2 Sigma(+)(u)) are detected as the major reactive species in the dry air GAD plasma region. These results suggest that the thermal (or Zeldovich) NOx formation mechanism is not significant in GAD system, while the energy level and the density of electrons in the plasma region will severely influence the NO2 formation. The presence of 500 ppm VOCs in the feed gases shows a limiting influence on the NO2 formation, which is in the order of aromatic hydrocarbon (C6H6 and C7H8)> straight-chain hydrocarbon (C4H10 and C6H14) > halogenated hydrocarbon (CCl4). The influences of VOCs chemical structure, supply voltage, feed gas humidity, and reactor geometry on NO2 formation are investigated, and the results correspond to above mechanism analysis. Based on the above, the possible pathways of the inhibition of NO2 formation in GAD-assisted VOCs decomposition process are discussed. (C) 2008 Elsevier B.V. All rights reserved.