Study on Products from Fuel-rich Methane Combustion near Sooting Limit Temperature Region and Importance of Methyl Radicals for the Formation of First Aromatic Rings
Study on Products from Fuel-rich Methane Combustion near Sooting Limit Temperature Region and Importance of Methyl Radicals for the Formation of First Aromatic Rings
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DOI：
10.1080/00102202.2020.1787394
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发表时间：
2020-07
影响因子：
1.9
通讯作者：
Keisuke Kanayama;A. Dubey;T. Tezuka;S. Hasegawa;H. Nakamura;K. Maruta
中科院分区：
文献类型：
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作者：
Keisuke Kanayama;A. Dubey;T. Tezuka;S. Hasegawa;H. Nakamura;K. Maruta
从极富燃料的甲烷/空气混合物（当量比为1.7-6.0，燃料与混合物的摩尔比为15- 38%）中生产单/双环芳烃以及较小的稳定物种在最高壁温为1300 K时，采用温度分布可控的微流反应器，研究了在温度接近炭黑生成极限时的炭黑生成规律。采用GC和GC/MS分析方法对O2、H2、CO、CO2、CH 4、C2 H2、C2 H4、C2 H6、苯、甲苯、苯乙烯和萘的物种进行了测定。一维计算也进行了几个详细的化学动力学。除了C2 H2（乙炔）外，大多数机理都很好地预测了较小的物种，特别是在中等当量比（1.3.0）下，C2 H2（乙炔）被所有机理高估。在高当量比（≤ 4.0）下，苯和萘的摩尔分数的测量值与计算值有很大的差异。反应路径分析表明，在中等当量比下，C2 H3与甲基自由基的反应对苯生成的贡献相对较小，而甲基自由基与C2 H2的生成存在竞争。因此，进一步考虑与甲基自由基反应的化学动力学的改进对于精确预测存在大量甲基自由基的产物是必要的。
ABSTRACT Productions of mono-/di-cyclic aromatic hydrocarbons as well as smaller stable species from extremely fuel-rich CH4/air mixtures (equivalence ratio of 1.7–6.0 and fuel-to-mixture ratio of 15–38 mol.%) near sooting limit in terms of temperature, were investigated using a micro flow reactor with a controlled temperature profile at maximum wall temperature of 1300 K. Species measurements of O2, H2, CO, CO2, CH4, C2H2, C2H4, C2H6, benzene, toluene, styrene and naphthalene were performed with GC and GC/MS analysis. One-dimensional computations were also conducted with several detailed chemical kinetics. Most of the mechanisms comparably well predicted the smaller species except C2H2 (acetylene), which was overestimated by all the mechanism especially at moderate equivalence ratio (Ø 3.0). There were large discrepancies between measured and computed mole fractions of benzene and naphthalene at high equivalence ratio (Ø 4.0). Reaction path analysis indicated that reaction pathway branched from C2H3 reacting with methyl radical, which competes with C2H2 production, showed relatively low contribution to benzene formation at moderate equivalence ratio. Therefore, improvements of chemical kinetics with further consideration of reactions with methyl radical are necessary for precise prediction of products where abundant amounts of methyl radical exist.