超超临界电站锅炉水冷壁管横向开裂原因分析

Analysis on the Causes of Transverse Cracking of Waterwall Tubes in Boilers of Ultra-supercritical Power Plants

煤电机组锅炉受热面的频发性开裂和失效是制约机组灵活高效运行的重要因素之一。利用宏观检查、金相实验、微观形貌分析、能谱分析、硬度检测等方法,深入研究超超临界电站锅炉水冷壁管横向开裂问题,分析问题产生原因,阐明水冷壁的开裂机理,提出了缓解水冷壁热膨胀、热疲劳的运行调整建议,完成燃煤机组灵活性调峰安全评价创新实践。

Frequent crackings and failures of boiler heating surfaces are one of the important factors that restrict the flexible and efficient operation of coal-fired power units.Multiple methods such as macroscopic inspection,metallographic experiments,microscopic morphology analysis,energy spectrum analysis,and hardness testing are applied to carry out in-depth research on the transverse cracking phenomena of waterwall tubes in boilers of ultra-supercritical power plants.Analysis is conducted on the causes of such problems,the cracking mechanism of waterwall is illustrated,and suggestions on operational adjustment are proposed to mitigate thermal expansion and fatigue of waterwall.Innovative practices in the safety evaluation of flexible peak regulation for coal-fired units are completed.