The dynamic evolution and interaction with dielectric material of the discharge in packed bed reactor
The dynamic evolution and interaction with dielectric material of the discharge in packed bed reactor
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DOI：
10.1088/1361-6595/ab844e
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发表时间：
2020-05
影响因子：
3.8
通讯作者：
Yao Li;Dezheng Yang;Jun-Jie Qiao;Li Zhang;Weizong Wang;Zilu Zhao;Xiongfeng Zhou;Hao Yuan;Wen‐Chun Wang
中科院分区：
文献类型：
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作者：
Yao Li;Dezheng Yang;Jun-Jie Qiao;Li Zhang;Weizong Wang;Zilu Zhao;Xiongfeng Zhou;Hao Yuan;Wen‐Chun Wang
本文采用不同介电常数的介质柱作为填充床反应器中的介质材料，研究了等离子体相互作用过程的动力学行为。研究了介电常数（氧化锆：ε = 25和PTFE：ε = 2.5）对等离子体催化应用中反应物种产生的影响。对比研究了氧化锆和聚四氟乙烯柱的放电图像、电特性、放电动态演化和时空分辨发射光谱。结果表明，填充床反应器中存在4种放电过程：介质柱表面流光放电、接触点局部放电、接地介质板表面放电和体放电。反应性物种如N2（C3 ~ u）、N2+（B2 ~ u+）和O（3 p5 P）的产生在很大程度上取决于放电过程。N2+（B2 u+）的产生总是伴随着电子直接碰撞过程激发基态氮分子为N2+（B2 u+）而形成流光。O（3 p5 P）以两种不同的方式产生，分别在电压脉冲上升和下降期间起主要作用。第一种方法是直接快速的一步电离和激发高能电子与O2。第二种方式是从氮亚稳态N2（A3 u+）和高能电子的能量转移，其中O首先从O2电离，然后被激发为O（3 p5 P）。此外，与氧化锆柱相比，PTFE柱更有利于反应物种的产生。
In this paper, dielectric columns with different dielectric constants are employed as dielectric materials in the packed bed reactor to investigate the dynamic behaviors of plasma interaction processes. The effects of the dielectric constants (zirconia: ε = 25 and PTFE: ε = 2.5) on the production of reactive species are studied for plasma catalysis applications. Comparison studies of discharge images, electrical characteristics, discharge dynamic evolution and spatial-temporal resolved optical emission spectroscopy are carried on when zirconia and PTFE columns are employed. The results show that there are four discharge processes existing in the packed bed reactor: surface streamer on the dielectric column, local discharge at the contact point, surface discharge on the grounded dielectric plate, and the volume discharge. The production of reactive species such as N2(C3Пu), N2+(B2Σu+) and O(3p5P) depend on the discharge processes to a great extent. The production of the N2+(B2Σu+) always accompanies the formation of the streamer by electrons direct impact process to excite the ground state nitrogen molecules to N2+(B2Σu+). The O(3p5P) is generated in two different ways, which plays a major role during the voltage pulse raising and falling time, respectively. The first way is the direct and fast one-step ionization and excitation by high energy electrons with O2. The second way is the energy transfer from the nitrogen metastable N2(A3Σu+) and energetic electrons, in which the O is first ionized from O2 and then excited to O(3p5P). Furthermore, compared with a zirconia column, a PTFE column is more conductive to the generation of reactive species.