某重沸器不锈钢换热管泄漏的原因  

Reasons for Perforation and Leakage of Stainless Steel Heat Exchange Tubes in a Reboiler

作　　者：汤鹏杰 梁斌 TANG Pengjie;LIANG Bin(Nanjing Jinchuang Non-ferrous Metal Technology Development Limited Company,Nanjing 211178,China;Nanjing Boiler and Pressure Vessel Inspection Institute,Nanjing 210019,China)

机构地区：[1]南京金创有色金属科技发展有限公司,南京211178 [2]南京市锅炉压力容器检验研究院,南京210019

出　　处：《腐蚀与防护》2023年第5期107-110,共4页Corrosion & Protection

摘　　要：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.H_2S 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.

关 键 词：S30403不锈钢 换热管 垢下腐蚀 穿孔 

分 类 号：TG172[金属学及工艺—金属表面处理]