煤粉锅炉富氧燃烧的数值模拟研究

NUMERICAL STUDY ON COMBUSTION PROCESS IN A COAL BOILERS WITH OXY-FUEL COMBUSTION

以一台600MW四角切圆煤粉锅炉为研究对象,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,进行了空气气氛和富氧气氛下炉内煤粉燃烧的数值模拟.模拟结果表明:O2/CO2气氛下,由于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.

Taking a 600 MW coal-fired boiler in a power plant serving as the object ot study, three dimensional structure of the furnace has been established and a mesh being produced through Gambit software. A reasonable mathematic model has been chosen from FLUENT soft- ware and the combustion in furnace being numerically simulated under condition of burning coals with different quality. In O2/CO2 atmosphere, CO2 has a higher specific heat capacity that heat storage capacity of the furnace flue gas and ignition heat increase, furnace overall temperature drops and the flame center moves. As the oxygen concentration increased, the combustion of pul- verized coal have been strengthened, the furnace temperature and the temperature inside the zone change, the flame center gradually moves down, which is in favor of the pulverized coal ignition and combustion.