600MW四角切圆燃烧锅炉富氧燃烧的数值模拟

Numerical simulation on 600 MW tangentially fired pulverized-coal boiler with oxygen-enriched combustion

为了研究煤粉锅炉的传热特性,控制燃煤污染物排放,阐述了600 MW四角切圆煤粉锅炉炉内的流动、传热与燃烧过程的数值模拟方法,通过Gambit软件建立炉膛的三维结构及网格生成,在FLUENT软件中选择合理的数学模型,分别进行了空气气氛和富氧气氛下炉内煤粉燃烧的数值模拟过程。模拟结果表明:O2/CO2气氛下,CO2具有较高的比热容,炉膛内烟气的蓄热能力及着火热增加,炉膛整体温度下降,火焰中心上移;随着氧气浓度的提高,煤粉的燃烧得到强化,炉内温度升高,炉内高温区变大,火焰中心逐渐下移,有利于煤粉的着火和燃烧。

In order to study the heat transfer of pulverized - coal fired boiler and control the pollutant emission, this paper expounds the numerical simulation method of flow, heat transfer and combustion process for 600 MW tangentially fired pulverized- coal boiler, and establishes the 3D structure and mesh generation of the furnace by Gambit and selects the reasonable mathematical model with FLUENT and carries out the numerical simulation of pulverized- coal combustion separately with air and enriched oxygen. The simulation result shows that with O2/CO2 ,which has higher specify heat capacity, the heat storage and ignition heat of flue gas in furnace are enhanced, and the flame center moves up with the decrease of furnace temperature;with the increase of oxygen concentration, the combustion of pulverized coal is strengthened, and the flame center moves down with the increase of furnace temperature and high -temperature area,which beneficial to ignition and combustion.