燃煤锅炉CO生成特性对锅炉效率及NO_(x)生成的影响机制

Influence Mechanism of CO Generation of Coal-Fired Boilers on Boiler Efficiency and NO_(x) Generation

以国内某600MW墙式切圆燃烧锅炉为研究对象,在炉膛关键区域布置了高温CO在线监测系统,通过试验与数值模拟计算,研究了炉膛CO生成特性与锅炉效率及NO_(x)排放的关联特性,并建立了低氮综合燃烧指数,以平衡锅炉高效燃烧与低氮排放之间的矛盾.研究结果表明,该锅炉效率随监测的炉膛CO浓度增大呈现先增大后减小的趋势,炉膛NO_(x)排放浓度随炉膛CO浓度的增大而逐渐降低;锅炉CO生成特性与锅炉效率及NO_(x)排放均表现出了显著相关性,优化炉膛CO生成特性能够使得锅炉燃烧效率与氮氧化物排放的综合性能实现优化.锅炉实际运行中,可通过监测与调控炉膛CO浓度,获得低氮综合燃烧指数最大值,以有效平衡锅炉效率与NO_(x)排放之间的矛盾,实现锅炉的高效、低氮运行.

A domestic 600MW wall-type tangentially burning boiler was taken as the research object,and a high-temperature CO online monitoring system was arranged in the key areas of the boiler.Through experiments and numerical simulation calculations,the correlation was studied among the boiler CO generation characteristics,the boiler efficiency and NO_(x)emissions.Finally,a low-NO_(x)combustion comprehensive index was established to bal-ance the contradiction between the boiler's high efficiency combustion and low NO_(x)emissions.The results show that the boiler efficiency increases firstly and then decreases with the increase of the monitored boiler CO concen-tration,while the boiler NO_(x)emission concentration continuously decreases with the rising boiler CO concentra-tion.The generation characteristic of boiler CO shows a significant correlation with both the boiler efficiency and NO_(x)emissions,and there is an optimal boiler CO concentration,at which the overall performance of boiler com-bustion efficiency and NO_(x)emissions can be optimized.In the actual operation of the boiler,by monitoring and regulating the CO concentration in the boiler,the maximum value of the low NO_(x)combustion comprehensive in-dex can be obtained,so as to balance the contradiction between the boiler efficiency and the NO_(x)emission,and then the operation of the boiler with high efficiency and low NO_(x)emissions can be realized.