2150 t/h切圆燃烧锅炉低氧燃烧的试验研究

摘要

In order to provide bases for the optimization of boiler low-oxygen combustion,experiments are performed on a 2 150-t/h tangentially fired boiler to study the influence of oxygen reduction on boiler combustion.The results show that under stable conditions,there is a peak value of the furnace temperature in the change of oxygen; on the upper and lower sides of the peak,the effects of oxygen reduction on combustion and boiler operation parameters are different.As oxygen varies,NOx emission has a peak value near the peak value of the furnace temperature,and a valley value in deep low-oxygen combustion.Decreasing oxygen can reduce NOx emissions only if the oxygen level lies between the peak and valley values of NOx emissions.Reducing oxygen enlarges the swirl number under steady operating conditions and the variation amplitude of swirl number in load decreasing,which easily leads to large steam temperature deviation and overheating.Oxygen reduction,which does not make obvious rise of the incomplete combustion loss,will enlarge the fluctuation range of the furnace temperature and NOx emissions in load changes.And conversely,if the incomplete combustion loss markedly increases,the load change has little effect on the furnace temperature and NOx emissions because of the influence of air flow on coal releasing heat.%为了给锅炉低氧燃烧优化提供依据,在2150 t/h四角切圆燃烧锅炉上进行了燃烧试验,以研究降低炉内氧量对锅炉燃烧的影响.结果表明:稳定工况下,炉膛温度随氧量变化存在一个峰值点,在峰值点两侧,降低氧量对燃烧和锅炉运行参数的影响不同；NOx排放在炉膛温度峰值点附近存在一个峰值点,在深度降低氧量时存在一个谷值点,仅当氧量位于峰谷值中间区域时,降低氧量能够降低NOx排放；降低氧量将加大稳定工况的旋流指数和降负荷过程巾旋流指数的变化幅度,易引起蒸汽温度偏差大、超温等问题;当降低氧量未使锅炉不完全燃烧热损失明显增加时,会加大变负荷过程炉温、N0x排放波动幅度,反之,变负荷时风量改变对燃煤放热量的影响,会使负荷变化对炉膛温度、N0x排放影响降至很小.