摘要
超超临界机组再热热段疏水罐发生泄漏会对人身和设备安全构成极大威胁。为了研究造成疏水罐泄漏的因素,本文以发生泄漏的某1 000 MW机组热段疏水罐为研究对象,对其内壁缺陷位置进行了无损检测、成分检验、组织分析、力学性能试验等,并从疏水罐的疏水逻辑、疏水阀位置、水位测量管路布置等多个角度进行分析。结果表明:这种泄漏主要由冷凝水与内壁作用导致的热疲劳引起;疏水不尽、疏水阀位置远离疏水罐底部、蒸汽在水位测量管路遇冷液化是造成疏水罐中冷凝水形成的重要原因;疏水罐罐口的湍流侵入效应、机组负荷变化、水位计管口冷凝水回流等因素使得疏水罐底部冷凝水液位面上下波动,造成较大范围热疲劳裂纹。为避免再次发生泄漏,需要在疏水罐的疏水逻辑、疏水阀位置、水位测量管路等方面进行改进。
The leakage failure of a drainage tank of reheat pipeline in ultra supercritical units will pose a great threat to personal and equipment safety. To find out the factors resulting in the drainage tank leakage, several tests such as non-destructive testing, component analysis, microscopic analysis and mechanical tests were carried out on defects position of inner wall of the drainage tank in hot section of reheat pipeline in a 1 000 MW unit. The factors such as the drainage logic of the drainage tank, the position of the drainage valve and the pipeline layout of the water level measuring were studied. It was found that the leakage of the tank was mainly caused by the thermal fatigue, which was resulted from the condensed water. Furthermore, the effect of turbulence invasion, the change of unit load, and the condensate return at the gauge nozzles made the liquid level fluctuate at the bottom of the tank, resulting in thermal fatigue cracks in a wide range. The reasons for the formation of condensate water included incomplete drainage, too far position of drainage valve, easy stream liquefaction in the water level measuring pipeline. In order to avoid re-leakage of the drainage tank of 1000 MW unit, it is necessary to improve the drainage logic, the location of the drainage valve, the nineline layout of the water level measuring and so on.
出处
《热力发电》
CAS
北大核心
2018年第1期130-135,共6页
Thermal Power Generation
基金
浙能集团科技项目(ZNKJ-2016-001)
关键词
超超临界机组
再热热段
疏水罐
泄漏
热疲劳
冷凝水
湍流侵入
失效分析
ultra supercritlcal unit, reheat pipeline, drainage tank, leakage, thermal fatigue, condensed water,turbulence invasion, failure analysis
