连续重整装置汽提塔顶空冷器管束泄漏原因分析  

Leakage analysis of stripper air cooler tube bundle in continuous reforming unit

作　　者：窦超 王天宇 王旸 马晶晶 DOU Chao;WANG Tianyu;WANG Yang;MA Jingjing(SINOPEC Jinling Company,Nanjing 210033,China;Nanjing Jinchuang Nonferrous Metal Technology Development Limited Company,Nanjing 211161,China)

机构地区：[1]中国石油化工股份有限公司金陵分公司,江苏南京210033 [2]南京金创有色金属科技发展有限公司,江苏南京211161

出　　处：《石油化工腐蚀与防护》2024年第3期61-64,共4页Corrosion & Protection In Petrochemical Industry

摘　　要：通过化学成分分析、金相组织分析、扫描电镜观察和能谱分析等方法,对连续重整装置汽提塔顶空冷器换热管穿孔的原因进行分析。结果表明,换热管材质的化学成分除了Si元素含量偏低以外,其他元素含量均符合10号钢材质的化学成分要求;换热管各处的金相组织均为铁素体+珠光体,并无明显差异;换热管外壁存在两层腐蚀产物,其中外层腐蚀产物主要为铁的氧化物,内层腐蚀产物主要为锌与铁的氧化物及水垢。镀锌的换热管在发生腐蚀前其表面曾发生过严重的结垢。换热管穿孔是由外部腐蚀造成的,腐蚀穿孔的机理为氧浓差电池腐蚀。由于换热管外表面垢层与外壁金属之间存在缝隙,缝隙内介质流动不畅,导致缝隙内外形成氧浓差电池,使结垢部位发生垢下腐蚀,最终导致其局部腐蚀减薄,直至穿孔。The reasons for perforation of heat exchange tube in stripper air cooler of continuous reforming unit were analyzed by means of chemical composition analysis,metallographic structure analysis,scanning electron microscopy observation and energy spectrum analysis.The survey found that the chemical composition of heat exchange tube material meets the chemical composition requirements of No.10 steel material except for the low content of Si element.Metallographic structure of each part of heat exchange tube is ferrite+pearlite with no significant difference.There are two layers of corrosion products on the outer wall of heat exchange tube,The outer corrosion products are mainly iron oxides,while the inner corrosion products are mainly zinc and iron oxides and scale.The surface of galvanized heat exchange tube had undergone severe scaling before corrosion occurred.Perforation of heat exchange tube was caused by external corrosion,mechanism of corrosion perforation is oxygen concentration cell corrosion.Due to poor medium flow in the gap between scale layer on outer surface of heat exchange tube and metal outer wall,concentration cell corrosion was developed inside and outside the gap,ultimately causing under-deposit corrosion at scaling area and leading to local corrosion thinning until perforation.

关 键 词：10号钢 汽提塔顶空冷器 换热管 外壁腐蚀 

分 类 号：TE986[石油与天然气工程—石油机械设备]