2000t/h四墙切圆锅炉炉内空气动力场试验研究

Experimental Study on Furnace Air Flow Field of a 2000t/h Tangentially Fired Boiler

通过模拟燃烧器热态设计工况,对一台660 MW超超临界锅炉PM型四墙布置切圆燃烧器进行了炉内冷态空气动力场试验研究。通过测量某一层燃烧器区域空气速度分布和衰减情况,研究了一次风速,一、二次风动量比和周界风风量等因素对四墙切圆燃烧方式下炉内空气动力场的影响规律。试验结果表明,四墙切圆燃烧器与四角切圆燃烧器有较大差别,冷态实际切圆形成主要取决于假想切圆直径,受一、二次风动量比和周界风量影响较小;降低了燃烧器向火侧火焰刷壁的可能性,更加有利于组织炉内燃烧,从而更好地控制炉膛出口热偏差、火焰中心高度和NOx排放量。

In order to predict hot state situation for the burners at designed parameters,full scale cold flow experiment was carried out in the PM type four wall tangentially fired furnace of a 660MW ultra supercritical boiler unit.The velocity distribution and jet decay in the burner area at a certain level was measured.Effects of the primary air velocity,momentum ratio of the primary to the secondary air and the border air flux on the flow field in the furnace were investigated.The results show that four wall tangentially fired burners are different from the four corner fired ones obviously.In cold state,the size of the practical tangential circle depends on that of the imaginary one,but is little related to the momentum ratio between the primary air to the secondary and border air flux.It lowers the possibility of the flame washing the wall and can also benefit the combustion organization in various aspects such as heat deviation control at the furnace exit,flame center altitude and NOx emission.