700MW四角切圆锅炉低氮运行特性分析

Low-NO_x Operating Characteristic Analysis in 700MW Tangentially Fired Boiler

针对700 MW锅炉主、再热蒸汽温度偏低、蒸汽温度偏差较大以及氮氧化物排放量偏高的问题,开展了低氮燃烧改造,采用三菱基于深度空气分级思想的MACT(Mitsubishi Advanced Combustion Technology)燃烧技术和M-PM(Multiple-Pollution Minimum)低NOx燃烧器,并进行了燃烧优化调整。改造及运行调整后,锅炉主、再热蒸汽温度达到设计值,两侧偏差基本消除,过热器和再热器均无超温风险,NOx排放量低于150 mg/Nm3,锅炉效率有所提高。结果表明,通过低氮燃烧改造和运行优化调整,协同实现了提高锅炉蒸汽温度和降低NOx排放的目的,提高了锅炉的安全、经济和环保性能。

In view of the problems from the 700 MW boiler, including the low main steam temperature and reheat steam temperature, the lager deviation on both sides of main steam temperature and reheat steam temperature and the excessive NOx emission, the combustion system was modificated by adopting Mitsubishi Advanced Combustion Technology based on the deep air-staged concept and Advanced-Pollution Minimum low-NOx burner, then the combustion optimization and adjustment were carried out. Through the adjustment and optimization, the boiler main steam temperature and reheat steam temperature returned to the design value, whose both sides of the deviation was basically eliminated. Meanwhile superheater and reheater had no risk of over-temperature, the NOx production is less than 150 mg/Nm^3, the boiler efficiency has been improved. It is found that through low NOx combustion modification as well as running optimization and adjustment, the purpose of improving boiler steam temperature and reducing NOx emissions has been achieved simultaneously, thus the safe, economic and environmental performance of the boiler has been improved to a large extent.