NOx-emissions from flameless coal combustion in air, Ar/O2 and CO2/O2
NOx-emissions from flameless coal combustion in air, Ar/O2 and CO2/O2
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DOI：
10.1016/j.proci.2008.06.025
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
H. Stadler;Dragisa Ristic;M. Förster;A. Schuster;R. Kneer;G. Scheffknecht
中科院分区：
文献类型：
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作者：
H. Stadler;Dragisa Ristic;M. Förster;A. Schuster;R. Kneer;G. Scheffknecht
无焰或“温和”燃烧是减少NOx排放的公知措施。本工作旨在将该技术应用于煤燃烧器。已经用褐煤以及烟煤进行了实验，其显示出在当前燃烧器设计下约20-50%的总NOx还原能力，这取决于燃料类型和燃烧器处的化学计量。最重要的设计特征是燃烧空气的高动量引起强烈的再循环，这减少了燃烧室中的温度变化和温度峰值，从而防止热NO形成。在Ar/O2和CO2/O2气氛下进行了氮氧化物排放的调查，以量化的燃料热NO的比例。这项调查表明，在无焰燃烧模式热NO的高度减少。它还表明，燃料NO的增加，这主要是有关的峰值火焰温度在无焰燃烧的下降。无焰燃烧中的强烈混合还允许在氧燃料条件下将氧化剂氧浓度降低至15体积%，而标准旋流燃烧器的氧化剂氧浓度为17体积%。
Flameless or ‘mild’ combustion is a well known measure to reduce NOx-emissions. This work aims at the application of the technique to coal combustors. Experiments have been carried out with lignite as well as bituminous coals showing an overall NOx-reduction capability with the current burner design of about 20–50% depending on fuel type and the stoichiometry at the burner. The most important design feature is a high momentum of the combustion air inducing a strong recirculation which reduces the temperature variations and temperature peaks in the combustion chamber and thus prevents thermal NO formation. An investigation of NOx-emissions under Ar/O2as well as CO2/O2atmospheres was carried out in order to quantify the ratio of fuel- to thermal-NO. This investigation showed a high reduction of thermal NO in the flameless combustion mode. It also showed an increase of fuel-NO which was primarily related to the decrease of the peak flame temperature in flameless combustion. The intensive mixing in flameless combustion also allows a reduction of the oxidiser oxygen concentration under oxyfuel conditions to 15vol % as compared to 17vol % with a standard swirl burner.