Reaction pathway for nascent soot in ethylene pyrolysis
Reaction pathway for nascent soot in ethylene pyrolysis
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DOI：
10.1016/j.combustflame.2016.02.008
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发表时间：
2016-05-01
影响因子：
4.4
通讯作者：
Yamaguchi, Togo
中科院分区：
文献类型：
--
作者：
Matsukawa, Yoshiya;Ono, Kiminori;Yamaguchi, Togo
在这项研究中，讨论了导致烟灰形成的多环芳烃（PAH）的生长机制。此外，通过比较烟灰和非烟灰条件下PAHs的浓度，研究了PAHs对烟灰成核的影响。原料乙烯在 1150-1730 K 的等温层流中热解，停留时间为 16-363 ms。使用气相色谱/质谱 (GC/MS) 的总离子色谱图 (TIC) 讨论了每个温度下 PAH 生长的反应途径。这些 TIC 表明，氢夺碳加成 (HACA) 和甲基加成/环化 (MAC) 机制是 1350 K 下大 PAH 的主要机制，而苯基加成/环化 (PAC) 在 1730 K 下也发挥着重要作用。本文鉴定了以前在烟灰模型中很少考虑的途径：通过苊二聚的途径；从苝到晕苯的途径；从四苯到苯并[k]四苯的途径。在 1730 K 的 TIC 中还检测到了一些重要的脂肪族碳氢化合物峰。使用氘化物通过 GC/MS 检查了热解产物的定量。在1730 K时，初生烟灰的数量浓度随着PAHs的摩尔分数的增加而增加。尽管多环芳烃的摩尔分数相对较高，分子量为200-300 u，但在1150 K 时没有观察到烟灰。这表明此类多环芳烃不是初生烟灰的前体。 (C) 2016 年燃烧研究所。由爱思唯尔公司出版。保留所有权利。
In this study, growth mechanisms of polycyclic aromatic hydrocarbons (PAHs) leading to soot formation were discussed. In addition, the effect of PAHs on soot nucleation was investigated by comparing the concentration of PAHs under sooting and non-sooting conditions. The feedstock ethylene was pyrolyzed in an isothermal laminar flow at 1150-1730 K with a residence time of 16-363 ms. Reaction pathways of PAH growth at each temperature were discussed using total ion chromatograms (TICs) of gas chromatography/mass spectrometry (GC/MS). These TICs suggest that the hydrogen-abstraction carbon-addition (HACA) and methyl addition/cyclization (MAC) mechanisms are the main mechanisms for large PAHs at 1350 K and that phenyl addition/cyclization (PAC) also plays an important role at 1730 K. This paper was the identification of pathways previously rarely considered in soot models: the pathway via dimerization of acenaphthylene; the pathway from perylene to coronene; the pathway from tetraphene to benzo[k]tetraphene. Some significant peaks of aliphatic hydrocarbons were also detected in the TIC at 1730 K. The quantification of pyrolysates was examined by GC/MS with deuterides. At 1730 K, the number concentration of nascent soot increased along with the mole fraction of PAHs. Despite a relatively high mole fraction of PAHs with molecular masses of 200-300 u, no soot was observed at 1150 K. This indicates that such PAHs are not precursors of nascent soot. (C) 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.