某300 MW亚临界锅炉高温再热器泄漏原因分析

Analysis of the Causes of Leakage of High⁃Temperature Reheater in a 300 MW Subcritical Boiler

高温再热器是亚临界锅炉中的一个重要组件,其主要作用是将排出锅炉的高温高压蒸汽再热至合适的温度,以提高锅炉的热效率。然而,在实际运行中,高温再热器泄漏问题时常出现,给锅炉正常运行和安全运行带来了一定的影响。对某300 MW亚临界锅炉高温再热器泄漏原因进行分析,通过对电厂所送管样的宏观形貌检查、几何尺寸测量、化学成分分析、金相分析、硬度试验和拉伸试验,结果表明,该300 MW亚临界锅炉高温再热器泄漏原因是长期超温导致管子力学性能劣化和微观组织老化、损伤所致的。

High-temperature reheater is an important component in subcritical boiler,and its main function is to reheat the high-temperature and high-pressure steam discharged from the boiler to a suitable temperature to improve the thermal efficiency of the boiler.However,in actual operation,high-temperature reheater leakage problems occur from time to time,which bring some impact on the normal and safe operation of the boiler.For this reason,the paper analyzes the causes of high-temperature reheater leakage in a 300 MW subcritical boiler,and the results of macroscopic morphology inspection,geometric dimension measurement,chemical composition analysis,metallographic analysis,hardness test,and tensile test of the tube samples sent to the power plant show that the cause of the leakage of the high-temperature reheater in the 300 MW subcritical boiler is the result of the deterioration of the mechanical properties of the tubes and the microstructures aging and damages due to the long term over-temperature.