Abstract In this paper, the effect of hydrogen addition on methane coupling in a microwave moderate pressure (55 mbar and 110 mbar) plasma reactor has been studied. The use of optical emission spectroscopy allowed the determination of the rotational temperature of heavy particles and showed it to be in the range of 3000–4000 K. Due to the high temperature in the discharge the dominant product was acetylene and it was concluded that the methane coupling process is mainly through thermal decomposition with a key role of H radicals. It was revealed that the addition of hydrogen can increase both methane conversion and acetylene and ethylene yield and selectivity. With the CH4:H2 ratio of 1:1, the methane conversion increased from 31.0% to 42.1% (55 mbar) and from 34.0% to 48.6% (110 mbar), when compared to pure methane plasma. Respectively, the yield of acetylene increased from 14.4% to 25.3% (55 mbar) and from 20.1% to 34.0% (110 mbar). Moreover, the addition of hydrogen decreased the output of the problematic soot-like product. These results indicate that hydrogen addition can be a simple yet effective method of increasing selectivity to desirable products in plasma reforming of CH4.

中文翻译：

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加氢对中压微波等离子体中甲烷耦合的影响

摘要 本文研究了加氢对微波中压(55 mbar和110 mbar)等离子体反应器中甲烷耦合的影响。使用光学发射光谱可以确定重粒子的旋转温度，并表明它在 3000-4000 K 的范围内。由于放电中的高温，主要产物是乙炔，得出的结论是甲烷偶联过程主要是通过热分解与H自由基的关键作用。结果表明，氢气的加入可以提高甲烷转化率以及乙炔和乙烯的产率和选择性。当 CH4:H2 比率为 1:1 时，与纯甲烷等离子体相比，甲烷转化率从 31.0% 增加到 42.1% (55 mbar) 和从 34.0% 增加到 48.6% (110 mbar)。分别，乙炔的产率从 14.4% 增加到 25.3% (55 mbar)，从 20.1% 增加到 34.0% (110 mbar)。此外，氢气的加入降低了有问题的烟灰状产品的产量。这些结果表明，在 CH4 的等离子体重整中，加氢是一种简单而有效的方法，可以提高对所需产物的选择性。