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$\le$3.0). There were large discrepancies between measured and computed mole fractions of benzene and naphthalene at high equivalence ratio (Ø$\ge$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.

摘要

_{由极度富含燃料的 CH 4} /空气混合物（当量比为 1.7-6.0 和燃料与混合物的比为 15-38 mol.%）接近碳烟产生单环/双环芳烃以及较小的稳定物质使用具有受控温度曲线的微流反应器在最高壁温 1300 K 下研究了温度限制。 O ₂、H ₂、CO、CO ₂、CH ₄、C ₂ H ₂、C ₂的物种测量H ₄ , C ₂ H ₆、苯、甲苯、苯乙烯和萘用 GC 和 GC/MS 分析。还用几个详细的化学动力学进行了一维计算。_{大多数机制都很好地预测了除了 C 2} H ₂ （乙炔）之外的较小物质，所有机制都高估了这一点，特别是在中等当量比（Ø$\le$3.0）。在高当量比（Ø$\ge$4.0）。反应路径分析表明，从C ₂ H ₃与甲基自由基反应分支的反应路径与C ₂ H ₂的生成竞争，在中等当量比下对苯的形成贡献相对较低。因此，需要进一步考虑与甲基自由基的反应来改进化学动力学，以精确预测存在大量甲基自由基的产物。