Chemical characterization of soot precursors and soot particles produced in hexane and diesel surrogates using an inverse diffusion flame burner
Chemical characterization of soot precursors and soot particles produced in hexane and diesel surrogates using an inverse diffusion flame burner
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DOI：
10.1016/j.fuel.2012.04.033
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发表时间：
2013-02
期刊：
影响因子：
7.4
通讯作者：
Mauricio Velasquez;F. Mondragón;A. Santamaría
中科院分区：
文献类型：
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作者：
Mauricio Velasquez;F. Mondragón;A. Santamaría
在这项研究中，我们介绍了液体燃料反扩散火焰中产生的碳烟颗粒和前体的化学和形态信息。研究发现，柴油替代燃料(SF)产生的碳烟是脂肪族正己烷火焰(H)的5倍。这种差异主要是由于芳烃和环己烷在初始SF中的贡献较大，这可能会显著影响第一碳烟粒子的早期演化。例如，由于热效应，随着火焰高度的增加，制造部分SF的脂环成分可能会经历快速的脱氢过程。结果是，生成了苯，因此通过FTIR观察到脂肪族基团的CH伸缩模式的下降，并通过1H-核磁共振证实了这一点。两种火焰的碳烟颗粒形态都变成了覆盖着液体物质的链状聚集体；导致颗粒边界不规则的特征。然而，与在低火焰位置获得的初级颗粒尺寸相比，主要是由于热和氧化过程，一次颗粒尺寸移动到较小的范围，这反过来又导致覆盖焦油物质的量减少，正己烷烟尘颗粒比SF烟尘颗粒更剧烈，可能是因为温度较高。
In this study, we present information of the chemistry and morphology of soot particles and precursors generated in inverse diffusion flames of liquid fuels. It was found that diesel surrogate fuel (SF) produces five times more soot than the aliphatic hexane flame (H). This difference is mainly due to the high contribution of both aromatic and cyclohexane fraction of the initial SF, which could significantly influence the early evolution of the first soot particle. For example, the alicyclic component that makes part of SF can suffer fast dehydrogenation processes as flame height increases due to thermal effects. As result, benzene is produced and therefore a declining in the CH stretching mode of the aliphatic groups is observed by FTIR and corroborated by1H-NMR. Soot particle morphology of both flames becomes chain-like aggregates covered with liquid material; characteristic that induces irregular boundaries of the particles. However, the primary particle size is shifted to small ranges compared to the ones obtained at low flame positions mainly due to thermal and oxidation processes, which in turn caused a reduction in the amount of covering tar material, being more drastic for hexane soot particles than for SF soot, probably because the temperature was higher.