Abstract

A kinetic analysis of the noncatalytic carbon dioxide reforming of CH₄ has been carried out in the temperature range of 1500–1800 K under conditions of variable temperature behind the reflected shock wave. The stages of methane conversion into syngas, the characteristic time intervals corresponding to these stages, and the most important elementary reactions have been established. At the first stage, as a result of thermal pyrolysis, methane molecules are sequentially converted into ethane, ethylene, and then acetylene, the most stable hydrocarbon in this temperature range. At the second stage, acetylene is normally converted into CO and H₂ and also into soot particles in the case of rich mixtures. The conversion of CO₂ proceeds at the second and third stages, when CH₄ conversion is almost complete. It occurs as a result of the interaction of CO₂ molecules with \({{{\text{H}}}^{\bullet }}\) atoms arising in the reacting system and leads to the formation of CO molecules and \({\text{O}}{{{\text{H}}}^{\bullet }}\) radicals. Acetylene is predominantly consumed in the reaction with \({\text{O}}{{{\text{H}}}^{\bullet }}\) radicals. The high concentration of acetylene during methane reforming promotes active formation of soot nuclei, for which acetylene makes the highest contribution to the rate of their surface growth. At the same time, acetylene itself is not a precursor of soot particle nuclei, which mainly form from \({{{\text{C}}}_{{\text{3}}}}{\text{H}}_{3}^{\bullet }\) radicals.

中文翻译：

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СО2 添加剂对天然气非催化转化为合成气和氢气的影响

摘要

_{在 1500–1800 K 的温度范围内，在反射冲击波后面的可变温度条件下，对 CH 4}的非催化二氧化碳重整进行了动力学分析。甲烷转化为合成气的阶段、与这些阶段对应的特征时间间隔以及最重要的基元反应已经建立。在第一阶段，由于热解，甲烷分子依次转化为乙烷、乙烯，然后是乙炔，乙炔是该温度范围内最稳定的碳氢化合物。在第二阶段，乙炔通常会转化为 CO 和 H ₂，并且在富混合物的情况下还会转化为烟灰颗粒。_{CO 2}的转化在第二和第三阶段进行，此时 CH ₄转化几乎完成。_{它是 CO 2}分子与反应系统中出现的 \({{{\text{H}}}^{\bullet }}\)原子相互作用的结果，并导致 CO 分子和\( {\text{O}}{{{\text{H}}}^{\bullet }}\)部首。乙炔主要在与\({\text{O}}{{{\text{H}}}^{\bullet }}\) 自由基的反应中消耗掉。甲烷重整过程中的高浓度乙炔促进了烟灰核的活跃形成，其中乙炔对其表面生长速率的贡献最大。同时，乙炔本身并不是烟尘粒子核的前体，烟尘粒子核主要由\({{{\text{C}}}_{{\text{3}}}}{\text{H}}_{3}^{\bullet }\) 部首。