超临界锅炉再热热段管道裂纹分析及寿命评估  

Crack Analysis and Lifespan Assessment of Reheat Section Pipes in Supercritical Boiler

作　　者：夏红伟[1] 任建辉[1] 杨见森 XIA Hongwei;REN Jianhui;YANG Jiansen(Special EquipmentInspection Instituteof Anhui,Hefei 230051,China)

机构地区：[1]安徽省特种设备检测院,安徽合肥230051

出　　处：《工业加热》2024年第11期81-84,共4页Industrial Heating

摘　　要：某型超临界锅炉再热热段管道内壁出现网状裂纹,裂纹分布于该处疏水管沿蒸汽流动方向约200 mm范围内。经宏观检查,无损检测以及扫描电镜形貌检查,判断其为热疲劳裂纹。通过查询该锅炉的运行记录,分析原因为再热蒸汽压力波动,导致疏水管道产生的冷凝水反复涌入再热热段管道,使其管道内壁产生热疲劳裂纹。运用有限元软件模拟出了疏水管内冷凝水产生的液面位置,即距离再热热段管道外壁超过30 cm的疏水管内再热蒸汽会全部冷凝为液态水。提出了避免产生此种热疲劳裂纹的解决方法,如调整疏水一次阀门的位置以及控制再热蒸汽压力的大幅度波动。最后对该段无裂纹的热段管道进行了寿命评估,得出剩余寿命约为61 722 h。A type of supercritical boiler's reheat section pipe had developed mesh-like cracks on the inner wall. The cracks were distributed in a range of about 200mm along the steam flow direction of the drain pipe. Through macroscopic inspection, non-destructive testing, and scanning electron microscopy(SEM) morphology analysis, it was determined that the cracks were caused by thermal fatigue. By analyzing the operating records of the boiler, it was found that the cause is the fluctuation of reheat steam pressure, which leads to repeated influx of condensate water from the drain pipe into the reheat section pipeline, causing heat fatigue cracks on the inner wall of the pipeline. The position of liquid surface generated by condensate in drain pipe is simulated by finite element software, showing that if the distance from the outer wall of the reheat section pipeline exceeds 30cm, all the reheated steam in the drain pipe will condense into liquid water. Solutions to prevent such heat fatigue cracks were proposed, such as adjusting the position of the primary drain valve and controlling large fluctuations in reheat steam pressure. Finally, a life assessment was conducted on the heat section pipeline without cracks, and it was determined that the remaining service life is approximately 61,722 hours.

关 键 词：热疲劳裂纹 有限元模拟 寿命评估 

分 类 号：TK228[动力工程及工程热物理—动力机械及工程]