某公司污水汽提装置氨精馏塔底的重沸器换热管使用不足2 a即发生穿孔泄漏。通过失效换热管管体宏观形貌观察、化学分析、显微组织观察以及管壁上垢层形貌和成分分析，对换热管穿孔泄漏的原因进行了研究。结果表明：换热管泄漏起源于外壁，溶解在壳程介质氨水中的H₂S电离产生HS^-，HS^-破坏换热管表面氧化膜，引起金属与溶解氧的腐蚀反应；生成的腐蚀产物逐渐沉积形成垢层，进而引发垢下腐蚀；同时，Cl^-在垢下闭塞区富集浓缩并引发自催化酸化效应，加速了垢下腐蚀，最终导致换热管穿孔泄漏。

Some heat exchange tubes in a reboiler at the bottom of ammonia rectification tower in sewage stripping plant of a company were perforated and leaked when used less than 2 a. The reasons for perforation and leakage of S30403 heat exchange tubes were investigated through macroscopic analysis, chemical analysis, microstructure observation for the failed tube body, morphology and composition analysis for the scale layer on the tube surface. The results showed that the heat exchange tube leakage originated from outer wall. H₂S dissolved in ammonia water on the shell side was ionized to produce HS^- which destroyed the oxide film on the surface of the heat exchange tubes, causing the corrosion reaction between metal and dissolved oxygen. The corrosion products deposited gradually and formed scale layer, leading to under-deposit corrosion. At the same time, enrichment and concentration of Cl^- in subscale occlusion area caused autocatalytic acidification and accelerated the progress of under-deposit corrosion, resulting in perforation and leakage of the heat exchange tubes finnally.