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对125 MW四角切向燃烧煤粉锅炉炉膛内的燃烧、传热过程进行研究,预测了不同空气温度下炉膛内的流场分布、温度分布和气相浓度分布。结果表明:各种工况下,炉内高温区出现在燃烧器区域,随着炉膛高度的增加,温度逐渐降低;相比低温区,高温区内的CO浓度较高,CO2和O2浓度较低;从各燃烧器喷口出来的气流围绕一个切圆运动,切圆直径内和贴近炉墙的气流速度都较低,其他区域气流速度较高;在达到工业生产要求的炉内温度时,二、三次风使用高温空气,可以降低总空气量和煤粉消耗量,同时还可以减少污染物的生成量,达到节能减排的目的;随着空气温度的升高,炉膛内同一截面的温度更加趋于均匀,这样水冷壁各管吸热均匀,有利于锅炉水循环的稳定性。
The combustion and heat transfer processes in a 125 MW tangentially fired pulverized coal fired boiler were studied, and the distribution of flow field, temperature distribution and gas phase concentration in the furnace at different air temperatures were predicted. The results show that the high temperature zone in the furnace appears in the burner zone under various operating conditions and the temperature decreases with the increase of the furnace height. Compared with the low temperature zone, the CO concentration in the high temperature zone is higher and the CO2 and O2 concentrations are lower ; The airflow from each combustor nozzle is circled around a tangent circle, the airflow velocity in the tangent circle diameter and the furnace wall close to each other is lower, and the air velocity in the other regions is higher; when the furnace temperature in industrial production is required, The tertiary air use of high temperature air, can reduce the total amount of air and coal consumption, but also can reduce the amount of pollutants generated to achieve the purpose of energy saving and emission reduction; with the air temperature, the same section of the furnace temperature more In uniform, so that all water-wall heat pipe evenly, is conducive to the stability of the boiler water cycle.