墙式分离燃尽风对660 MW切圆燃烧锅炉烟温偏差影响的数值模拟研究

摘要

To study the effect of wall separated over-fire air (SOFA)on flue gas temperature deviation,numerical simulation on furnace flow,combustion and pollutant emission under multiple loading conditions for a 660 MW tangentially coal-fired boiler was carried out. The effect of SOFA air rate and swinging angle onthe flue gas temperature deviation was investigated carefully. The simulation results indicate that increase of air rate of SOFA causes sectional temperature unevenness coeffi-cient of smokestack at the furnace exit and sectional flue gas temperature deviation at the furnace exit both decrease and makes for reducing NOx emission without large impact on burn-off rate of pulverized coal. Meanwhile,level swinging angle of SOFA nozzle extends and SOFA nozzle swings downward,which are both good to reduce flue gas temperature deviation of the boiler.%为研究墙式分离燃尽风(separated over-fire air,SOFA)对切圆燃烧锅炉烟温偏差的影响效果,对1台660 MW四角切圆燃烧锅炉开展了多工况炉内流动、燃烧和污染物排放数值模拟,研究了墙式 SOFA风率和摆角对锅炉烟温偏差的影响。结果表明：SOFA风量增加,使得炉膛出口烟窗截面温度分布不均匀系数和炉膛出口截面烟温偏差减小,并且有利于降低NOx 排放量,但对煤粉燃尽率影响不大；SOFA喷口水平摆角增大,有利于降低锅炉烟温偏差；SOFA喷口向下摆动,有利于降低锅炉烟温偏差。