水煤浆MILD燃烧数值模拟研究

为解决水煤浆常规燃烧存在的运行稳定性差等问题,以IFRF炉为研究对象,采用数值模拟方法尝试对水煤浆燃料进行了MILD燃烧研究。结果表明,在燃料输入功率不变的条件下,水煤浆MILD燃烧相对于常规旋流燃烧,流场的回流区域更大,烟气循环更加强烈,整体的炉膛温度更低,分布更加均匀,峰值温度最高降低了227 K,燃烧反应速率更慢,燃烧反应区面积存在区域更大,整个炉膛基本处于低氧氛围下,尾部烟气中的NO_x排放降低了50%以上。此外,水煤浆浓度的改变对炉膛流场几乎没有影响,但可以降低炉膛整体温度以及尾部烟气中NO_x排放。

Numerical simulation of MILD combustion on coal-water slurry

In order to solve the problems of poor operation stability of CWS (coal-water slurry) combustion,the MILD (moderate or intense low oxygen dilution) combustion characteristics of CWS were studied numerically based on the pilot-scale furnace of IFRF.Results show that under the same fuel input,the MILD combustion of CWS has extensive backflow region than the conventional swirl combustion,more intense flue gas circulation,lower and more uniform distribution of furnace temperature.The maximum peak temperature is reduced by 227 K.The rate of combustion reaction is slower,and the area of combustion reaction zone is larger.The whole furnace is in a low oxygen atmosphere,and the emission of NOx is dramatically reduced by more than 50％.In addition,different concentrations CWS have little effect on flow distribution,but it can lower the temperature in the whole furnace and reduce the final NOx emission.