原油蒸馏装置常压塔顶回流管腐蚀失效分析与对策  

Corrosion failure analysis and countermeasures for reflux line of atmospheric tower in crude distillation unit

作　　者：朱林利 ZHU Linli(SINOPEC Shanghai Petrochemical Co.,Ltd.,Shanghai 200540,China)

机构地区：[1]上海石油化工股份有限公司炼油部,上海200540

出　　处：《石油化工腐蚀与防护》2022年第3期60-64,共5页Corrosion & Protection In Petrochemical Industry

摘　　要：某公司2.5 Mt/a原油蒸馏装置常压塔塔顶回流管线严重腐蚀失效,现场检查发现塔顶冷回流管线的焊缝部位腐蚀开裂和穿孔,塔顶循环回流管线的表面腐蚀开裂。通过失效部位的宏观和微观组织检查、腐蚀产物检测,并结合工艺操作和腐蚀介质组成分析发现,腐蚀失效的主要原因是回流管材质奥氏体不锈钢对Cl;存在敏感性,在塔顶低温H;S-HCl-H;O腐蚀环境中,特定材料制成的回流管在拉应力作用下发生了应力腐蚀开裂,尤其在强度较高的接管焊缝等存在残余应力及承担工作负荷的位置易发生腐蚀开裂。根据常压塔顶回流管线腐蚀失效的原因分析,提出了相应的解决措施。Serious corrosion failure was found in reflux line of atmospheric tower in a 2.5 Mt/a crude distillation unit. Field inspection revealed that there is corrosion cracking and perforation at the welds of cold reflux line, as well as the surface of circulating reflux line. Causes were studied by employing the methods of macro and micro structure inspection, corrosion product detection, process operation analysis, composition analysis of corrosive medium, it was concluded that austenitic stainless steel material of reflux line is sensitive to Cl;under low-temperature H;S-HCl-H;O corrosion environment at top of atmospheric tower. Under such environment, stress corrosion cracking occurred in reflux line with the influences of specific material and tensile stress, severe corrosion cracking preferentially occurred especially at welding seam with residual stress and bear working load. Countermeasures are advised accordingly.

关 键 词：原油蒸馏装置 塔顶低温腐蚀 回流管线 应力腐蚀开裂 不锈钢 

分 类 号：TE986[石油与天然气工程—石油机械设备]