基于雨流计数法的锅炉汽包寿命实时监测

建立了汽包温度场、应力场监测模型,基于从电厂DCS(分布控制系统)中取出的锅炉汽包启动数据,通过有限元分析确定汽包的危险点,并修正了该点的应力集中系数,给出了汽包瞬态温度场计算的隐式差分方法和危险点的当量应力计算公式,改进了雨流计数方法,提出了采用应力稳定原则作为判定汽包启停状态结束的准则,统计每次启停过程中不同应力幅的循环次数,并据此确定汽包的寿命损耗。通过对锅炉汽包一次冷启动数据分析,验证了本文方法的有效性,研制了锅炉汽包寿命实时监测系统,经600 MW机组锅炉汽包的监测运行表明,效果良好,达到了对锅炉汽包寿命损耗进行实时监测并指导运行的目的。

Boiler Drum Life Real-time Monitoring Based on a Rain-flow Counting Method

A model for monitoring the temperature and stress profiles of boiler drums has been established.Based on the start-up data of a boiler drum acquired from the DCS(distributed control system) of a power plant,the hazardous point on the boiler drum can be determined from a finite element analysis and the stress concentration factor at that point also corrected.An implicit difference method to calculate the transient temperature profile of the boiler drum and the equivalent stress calculation formula of the hazardous point were given,thereby improving the rain-flow counting method.Proposed is a criterion for judging the completion of boiler drum startup and shutdown process by adopting a stress stabilization principle.The number of different stress amplitude cycles at each startup and shutdown process was added up and on this basis the life wastage of the boiler drum determined.By analyzing the data acquired from a cold startup of the boiler drum,the authors have verified the effectiveness of the method under discussion and thereby developed a real-time system for monitoring the service life of boiler drums.The boiler drum monitoring operation of a 600 MW turbo-generator boiler drum shows the effectiveness of the method in achieving the aim of performing a real-time monitoring of boiler drum life wastage and of providing guidance for their operation.