尾气处理装置烟气加热器腐蚀失效原因分析

Cause analysis of corrosion failure in flue gas heater of tail gas treatment unit

摘要:
目的分析某天然气净化厂康索夫(Cansolv)尾气处理装置烟气加热器出现严重腐蚀失效的原因。
方法分析了烟气加热器管束的腐蚀环境，开展了材料理化性能、腐蚀产物成分及微观形貌等失效原因分析。
结果失效管束的理化性能符合要求，管束泄漏处呈坑状和蜂窝状，部分沟槽尖端有裂纹，且深入基体，呈现应力腐蚀的特征。
结论烟气加热器在高温、高酸液含量的环境下发生了电化学腐蚀和应力腐蚀，导致管束出现腐蚀泄漏。

Abstract:
Objective The aim is to analyze the causes of serious corrosion failure of flue gas heater in Cansolv tail gas treatment unit of a natural gas purification plant.
Methods The corrosion environment of the flue gas heater tube bundle was analyzed, and the failure reasons, such as the physical and chemical properties of the material, the composition of the corrosion products and the micro-morphology were analyzed.
Results The physical and chemical properties of the failed tube bundle met the requirements. The leakage area of the tube bundle was pit-shaped and honeycomb-shaped, and some groove tips had cracks that penetrate deep into the substrate, exhibiting stress corrosion characteristics.
Conclusions The electrochemical corrosion and stress corrosion occurred in the flue gas heater under high temperature and high acid content, resulting in corrosion leakage of the tube bundle.