低温过热器泄漏原因分析及预防措施OA

The frequent low-load operation of coal-fired power plants due to their participation in peak shaving lead to low flue gas tem-peratures at the inlet of SCR systems,to address this issue,adding an economizer flue gas bypass is a commonly adopted technical so-lution.After the bypass flue is put into operation,the inlet pipe of the low-temperature superheater is repeatedly scratched and cracked.Firstly,for Unit 1 boiler in some power plant,a bypass flue is created by making openings on the fins of tube panels below the inlet header of the low-temperature superheater,diverting high-temperature flue gas to the SCR system inlet.Secondly,through a comprehensive analysis of the causes of crack formation,it concludes that restricted expansion and alternating stress concentration are the main reasons for crack generation.Fianlly,it proposes preventive measures,a non-metallic expansion joint is implemented to effectively separate the economizer bypass flue from the rear wall of the rear flue.This flexible connection allows independent thermal expansion of both components without mutual interference,thereby eliminating safety risks in the boiler's"four tubes".It can provide a reference for low-temperature superheaters with similar problems.