为探究循环流化床（CFB）锅炉的低NOx排放性能，在热输入功率为81.3 kW的CFB热态实验台上研究了燃煤平均粒径与二次风对NOx原始生成量的影响，考察了以碳酸氢铵为还原剂，以碳酸钠和乙醇为添加剂的选择性非催化还原（SNCR）低温脱硝增效性能。结果表明：随燃煤平均粒径的减小，NOx生成量降低；提高二次风比例及二次风口位置可降低NOx生成量；以碳酸氢铵为还原剂的SNCR法在氨氮摩尔比为1.7时脱硝效率达到65.2%，还原剂利用率达到峰值；在650~800 ℃的低温范围内，添加碳酸钠较无添加剂工况的脱硝效率平均提升24.5个百分点，750 ℃时的脱硝效率提升34.8个百分点；添加乙醇后的低温区效率平均提升28.2个百分点，温度低于700 ℃时增效性能优于添加碳酸钠工况；添加剂主要通过自由基链式反应提升SNCR法的低温脱硝性能。

In order to explore the low NOx emission performance of circulating fluidized bed (CFB) boiler, on a thermal state test rig with input power of 81.3 kW, the effects of the average particle size of coal and the secondary air on the original NOx generation were studied, the synergistic denitration performance of selective noncatalytic reduction (SNCR) at low temperature was investigated with ammonium bicarbonate as reducing agent and sodium carbonate and ethanol as additives. The experimental results show that the NOx generation of CFB boiler decreases with the decrease of average particle size of coal; increasing the proportion and the vent position of secondary air can decrease NOx generation; the SNCR method with ammonium bicarbonate as reducing agent achieves a denitration efficiency of 65.2% at an ammonia to nitrogen molar ratio of 1.7, with peak reducing agent utilisation; in the low temperature range of 650-800 ℃, the denitration efficiency with sodium carbonate is increased by 24.5 percentage points on average compared with that without additive, and at 750 ℃, the denitration efficiency is increased by 34.8 percentage points; after adding ethanol, the average efficiency of low temperature zone is improved by 28.2 percentage points, and the synergistic performance is better than that of adding sodium carbonate when the temperature is lower than 700 ℃; the additive enhances the lowtemperature denitration performance of SNCR mainly by simulating the free radical chain reaction.

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国家重点研发计划（2020YFB0606300）