Study of polycyclic aromatic hydrocarbons (PAHs) in hydrogen-enriched methane diffusion flames
Study of polycyclic aromatic hydrocarbons (PAHs) in hydrogen-enriched methane diffusion flames
复制标题
DOI：
10.1016/j.ijhydene.2019.01.253
复制
发表时间：
2019-03
影响因子：
7.2
通讯作者：
Chinonso Ezenwajiaku;M. Talibi;N. Doan;N. Swaminathan;R. Balachandran
中科院分区：
文献类型：
--
作者：
Chinonso Ezenwajiaku;M. Talibi;N. Doan;N. Swaminathan;R. Balachandran
多环芳烃（PAHs）是煤烟的致癌成分。需要详细了解多环芳烃的形成特征，以制定有效的策略来减少多环芳烃的形成和减少燃烧装置中的烟尘。本研究提出了一种实验方法，利用平面激光诱导荧光（PLIF）同时成像多环芳烃和羟基自由基（OH），分析有氢（H2）和没有氢（H2）的非预混甲烷-空气火焰中多环芳烃的形成特征。用OH PLIF表示火焰前缘的峰值温度区域。在相同的燃料混合条件下，进行了一维反喷层流非预混火焰模拟。这项工作描述了两组研究趋势的比较。多环芳烃荧光强度值随燃烧器上方高度的增加而增加，但随h2o2的加入而降低。这种观察到的多环芳烃荧光变化率（即多环芳烃生长特性）表明了燃料混合物的烟尘潜力。实验得到的多环芳烃荧光和模拟得到的多环芳烃浓度随h2加成量的增加而明显降低。在靠近燃烧器尖端的位置添加h2o2，多环芳烃荧光信号减少的百分比与火焰模拟中观察到的百分比相似。添加h2h后，多环芳烃的减少可能是由于乙炔和丙炔浓度的降低以及h提取速率的降低，从而降低了多环芳烃生长的活性位点的可用性。所提出的多环芳烃测量的实验方法可以很容易地应用于任何燃料混合物。
Polycyclic aromatic hydrocarbons (PAHs) are the carcinogenic components of soot. Detailed understanding of PAH formation characteristics is required for development of effective strategies to curtail PAH formation and reduce soot in combustion devices. This study presents an experimental methodology to analyse PAH formation characteristics of a non-premixed methane-air flame with and without hydrogen (H2) addition, using simultaneous planar laser induced fluorescence (PLIF) imaging of PAH and hydroxyl radical (OH). OH PLIF was used to represent peak temperature regions in the flame front. One-dimensional, opposed-jet laminar non-premixed flame simulations were also carried out for the same fuel mixture conditions. This work describes comparison of trends from both sets of studies. PAH fluorescence intensity values were observed to increase with increasing height above burner, however this rate of increase reduced with H2addition. This observed rate of change in PAH fluorescence (that is, PAH growth characteristics) is indicative of the sooting potential of the fuel mixture. PAH fluorescence from experiments and PAH concentration from simulation show strong reduction with increase in H2addition. The percentage reduction in PAH fluorescence signal with H2addition closer to the burner tip was of a similar magnitude to that observed with flame simulations. The reduction in PAH with H2addition could be attributed to the reduction in acetylene and propargyl concentrations, and reduced H-abstraction rates, which reduced the availability of active sites for PAH growth. The proposed experimental methodology for PAH measurements can be readily applied to any fuel mixtures.