Plasma activation of methane for hydrogen production in a N-2 rotating gliding arc warm plasma: A chemical kinetics study
Plasma activation of methane for hydrogen production in a N-2 rotating gliding arc warm plasma: A chemical kinetics study
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N-2 旋转滑翔弧暖等离子体中甲烷的等离子体活化产氢：化学动力学研究
DOI：
10.1016/j.cej.2018.03.123
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发表时间：
2018
影响因子：
15.1
通讯作者：
Tu Xin
中科院分区：
文献类型：
--
作者：
Zhang Hao;Wang Weizong;Li Xiaodong;Han Long;Yan Mi;Zhong Yingjie;Tu Xin
本文采用化学动力学方法研究了甲烷在温等离子体中的活化制氢过程，N2旋转滑动弧（RGA），首次进行了新的见解的潜在的反应机制和途径。建立了一个零维化学动力学模型，该模型在CH4转化率和产物选择性方面与实验结果吻合较好，使我们能够更好地理解各种重要物种及其相关反应对CH4、H2和C2H2等生成和损失的相对重要性.获得了一个整体反应方案，以提供等离子体化学的真实画面。结果表明，电子和激发态氮物种（主要是N2（A））在CH4的初始解离中起主导作用。而H原子诱导的反应CH4+ H → CH3+ H2，由于气体温度较高（超过1200 K），反应速率加快，是CH4转化率和H2生成率的主要贡献者，当只考虑正向反应时，其相对贡献率分别>90%和> 85%。旋转滑动弧温等离子体中热化学和等离子体化学过程的共存和相互作用显著提高了工艺性能。C2碳氢化合物的形成遵循C2 H6 → C2 H4 → C2 H2的近单向路径，解释了C2产物选择性按C2 H2> C2 H4> C2 H6的顺序降低的原因。
In this work, a chemical kinetics study on methane activation for hydrogen production in a warm plasma, i.e., N2rotating gliding arc (RGA), was performed for the first time to get new insights into the underlying reaction mechanisms and pathways. A zero-dimensional chemical kinetics model was developed, which showed a good agreement with the experimental results in terms of the conversion of CH4and product selectivities, allowing us to get a better understanding of the relative significance of various important species and their related reactions to the formation and loss of CH4, H2, and C2H2etc. An overall reaction scheme was obtained to provide a realistic picture of the plasma chemistry. The results reveal that the electrons and excited nitrogen species (mainly N2(A)) play a dominant role in the initial dissociation of CH4. However, the H atom induced reaction CH4+ H → CH3+ H2, which has an enhanced reaction rate due to the high gas temperature (over 1200 K), is the major contributor to both the conversion of CH4and H2production, with its relative contributions of >90% and >85%, respectively, when only considering the forward reactions. The coexistence and interaction of thermochemical and plasma chemical processes in the rotating gliding arc warm plasma significantly enhance the process performance. The formation of C2hydrocarbons follows a nearly one-way path of C2H6→ C2H4→ C2H2, explaining why the selectivities of C2products decreased in the order of C2H2> C2H4> C2H6.