循环流化床锅炉脱硝改造异常的原因分析与解决方法

摘要

The theoretical analysis and the site acceptance test are carried out to solve the problem of the distorted data collected on site existed in the SCR denitration renovation of a 220t/h circulating fluidized bed boiler. Results show that the temperature sensor has high measurement accuracy and very small measurement error based on radiation heat transfer may be neglected when the heating surface temperature arranging around temperature sensor get close to flue gas temperature, and the temperature sensor has a big error when the heating surface temperature arranging around temperature sensor is very different with flue gas temperature. The suggestion for this issue was put forward. The analysis is significative for monitoring boiler heating surface temperature, improving boiler burning, properly arranging SNCR and SCR denitration and reducing boiler Nox emission,and so on.%针对某电厂220t/h循环流化床锅炉尾部SCR脱硝改造出现现场采集数据失真的问题,进行了理论分析及现场验证.结果表明:当测温元件环境温度与烟气温度接近时,测温元件与背景之间的辐射换热基本可忽略,测量准确度高,测量误差很小;当测温元件周围存在温度较低的受热面时,测温元件所测数据与实际烟气温度存在较大误差.针对该问题,提出改造建议.这些对有效监测锅炉各受热面的温度分布,优化锅炉燃烧、合理布置炉内SCNR及SCR脱硝、降低NOx排放等方面有一定的指导意义.