S Zorb管板组件反吹接管裂纹故障分析及处理

Failure analysis of cracks on backflush nozzle weld of S Zorb filter tube sheet and treatment

介绍了S Zorb反应器过滤器的基本结构、设计及操作参数以及管板组件反吹接管焊缝产生裂纹、泄漏及修复的情况。从设计、制造、安装、管理4个角度分析了泄漏原因,认为管板与反吹接管焊接结构设计不合理;设备运行中存在疲劳应力;焊缝存在原始缺陷;由于泄漏导致管板工况变化;焊缝部位出现再热裂纹是这次事故的主要原因。管板利旧时没有做必要的检验,缺陷没有及时发现则是导致泄漏的另一原因。为此提出以下改进措施:将管板与反吹接管的焊接形式由角焊缝改进为对接焊缝;增加焊缝硬度检验和接管水压试验工序;安装时要求反吹系统管线无应力配管;加强设备备件质量管理等。

Here introduced are the construction, design and operating parameters of the reactor effluent filter of S Zorb unit as well as backflush nozzle weld cracks, leakage, and repair of the tube sheet. The causes of leakages were analyzed in respect of design, fabrication, installation and management. It is concluded that the main culprits of failure were inappropriate welding structure design of tube sheet and backflush pipe, fatigue stress in the operation of equipment, existence of original defects in welds, changes of tube sheet conditions caused by leakages and reheat cracking on the welds. Another reason is that the lack of the necessary inspection of old tube sheet led to failure to find the defects. To solve these problems, some improvement measures were proposed such as the improvement of welding structure of tube sheet and backflush pipe by replacing fillet weld with butt weld, additional hardness inspection of welds and hydraulic testing of blowbaek pipe, stress-free piping in installation of backflush system pipeline and strengthened quality management of equipment spare parts.