660 MW超临界W火焰锅炉低负荷稳燃特性研究

Investigations of Combustion Stability in a 660 MW Supercritical W-Flame Boiler Under Low Load

“碳中和”、“碳达峰”的提出预示着未来煤电机组将在更低的负荷运行,用于燃烧无烟煤、贫煤等低挥发份煤种的W火焰锅炉低负荷运行时会出现燃烧稳定性问题。以某660 MW超临界W型火焰锅炉为对象开展了针对低负荷稳燃特性的研究,进行了100%、60%、55%、45%THA工况的试验研究与数值模拟解析,35%THA工况理论预报。结果表明由于炉膛温度降低、煤粉变细、煤粉浓度降低的综合影响,负荷对煤粉颗粒的着火距离影响不大;低负荷工况下投运两侧燃烧器、减少乏气风的射入量有利于提高燃烧稳定性;通过数值模拟可知35%THA工况无法保持炉内高温火焰稳定燃烧,模拟预报锅炉会熄火。

The proposal of carbon neutrality and peak carbon emissions indicated that the thermal power generating units will operate at lower load in the near future.The combustion stability is the key problem especially for the W-flame boiler with low volatile coal burnt,such as anthracite or lean coal.Therefore the combustion stability under low loads was studied in a 660 MW supercritical W-flame boiler through a series of experiments and CFD modeling work at 100%,60%,55%,45%and 35%THA conditions.The results show that the load has little effect on the ignition distance of pulverized coal particles due to the comprehensive effects of the lower temperature in the furnace,the finer pulverized coal and the decreased concentration of the pulverized coal.The operation of burners on both sides and the reduction of exhaust air injection amount are beneficial to improve the combustion stability under low load condition.It is clear that the high temperature flame in the furnace cannot be kept under the condition of 35%THA.And the flame in the boiler will be extinguished in the predicted results of numerical simulation.