煤掺混燃烧时氮析出特性的试验研究

Experimental Study on Nitrogen Release During Combustion of Blended Coal

在一维煤粉燃烧试验台上对电站动力用单种煤及其混煤燃烧时氮氧化物的析出特性进行了试验研究,主要探讨组分煤种的煤质比例以及掺混比例对氮氧化物析出的影响规律。研究结果表明:NOx主要是在煤粉着火过程中产生的,其生成量与煤中的氮含量和挥发分含量密切相关;混煤燃烧时,各组分煤种氮的析出是既独立又相互影响的,混煤氮的析出曲线一般具有“双峰”结构,峰值区域较宽,其NOx生成量与各组分煤种的氮含量基本呈线性关系。掺烧比例对混煤氮的析出有较大影响,在贫煤中掺混其它煤种时,混煤氮的析出时间、析出浓度与各组分煤种的加权平均值有一定差异。

Release characteristics of nitrogen containing pollutants during the combustion of individual kinds of coal, as well as their mixtures, have been experimentally studied with the help of a one-dimensional pulverized coal combustion test rig. In the main, the effect of properties of different coal categories and their mixtures on the release of nitrogen containing pollutants were investigated. Study results show that NOX is primarily emitted during pulverized coal＇ s ignition process and is strongly influenced by the coal＇s nitrogen and the volatile content; when mixed coal is fired the nitrogen release curve usually exhibits two peaks with a relatively broad extent. The amount of NOx emitted is approximately linearly related with the nitrogen contained in the relevant coal categories, and is thus strongly effected by the proportional content of the coal mixture. In case lean coal is blended with other coal categories, the time of emission, and its concentration, are somewhat different from those, calculated by the weighted average of the ingredients.