燃烧器上摆角度对四角切圆锅炉再热蒸汽温度偏差影响的数值模拟

采用燃烧器上摆和附加风上摆角度偏差设置的方法来降低锅炉烟温偏差和再热蒸汽温度偏差。对一台700 MW四角切圆燃烧锅炉不同燃烧器上摆角度条件下的炉内燃烧过程进行了数值模拟,模拟结果与试验值符合较好。燃烧器上摆角度增加,炉内气流的旋转动量矩和屏区入口的残余旋转动量矩减小,水平烟道内烟气速度和温度偏差降低。附加风上摆角度的偏差设置可降低屏区入口的残余旋转动量矩,进而减小烟气速度和温度偏差。燃烧试验表明,燃烧器上摆11°和附加风上摆角度的偏差设置10°可将再热蒸汽温度偏差由20℃左右降低至4℃以下,是一种有效降低烟气和再热蒸汽温度偏差的手段。

Numerical simulation on effect of burner tilting up angle on reheat steam temperature deviation for tangentially fired pulverized-coal boiler

The burner tilting up and the bias setting of AA tilting up angle was employed in order to reduce the temperature deviation of flue gas and reheat steam. The combustion processes in a 700 MW tangentially fired boiler with different burner tilting up angles were numerically simulated. The simulated results were fitted in with the measured data well. For greater burner tilting up angle, the swirling momentum moment in the furnace and the residual swirling momentum moment in the entrance of platen zone were reduced, while the flue gas deviation in the horizontal flue gas pass was lower. The bias setting of AA burner tilting up angle can reduce the flue gas residual swirling momentum moment of the entrance of platen zone considerably and lower the deviation of the flue gas temperature and velocity. The combustion tests showed that as an effective measures to reduce the temperature deviation of flue gas and reheat steam of this boiler, the burner tilting up for 11° and the bias setting of AA tilting up angle for 10° can reduce the temperature deviation of reheat steam from 20℃ to about 4℃.