新建350MW超临界机组典型缺陷分析及处理

分别对呼和浩特热电厂扩建的2台350 MW超临界空冷火力发电机组在基建监督检查中发现的锅炉、汽轮机和四大管道等主要设备存在的承重部件焊缝裂纹、未熔合,P91材料集箱开裂及内壁氧化严重,P91材料集箱硬度异常,集箱内部存在大量异物,弯管壁厚减薄超标,大型铸件及径向支撑轴瓦等缺陷的产生原因及可能对机组安全、稳定运行造成的影响进行了分析,并采取了相应的补焊、重新加工处理及更换等措施,为保证机组投运后的安全稳定运行奠定了基础,并为开展超(超)临界火力发电机组的基建监督检查工作提供参考。

Analysis on Typical Flaws of Construction Supervision and Detecting for 350 MW Supercritical Power Units

Respectively, the flaws which were found in boilers, turbines and other major equipments of two new air-cooled 350 MW supercritical units in Hohhot Thermal Power Plant were analyzed. These flaws contain cracks and faulty fusion of load-bearing parts welds, cracking and oxidized seriously of P91 header, abnormal hardness of P91 header, there were lots of impurity in headers, excessive bending wall thinning, large castings and bush defects. The generation cause of flaws and effect on long-term safety and stability were analyzed, and taking the appropriate welding, re-processing and replacement of other measures to ensure the safety and stability of the units. All of these could provide reference to construction supervision and detecting of uhra-supercritical thermal power units.