轻烃回收装置吸收塔腐蚀分析及对策

Corrosion Analysis and Countermeasures of Absorption Tower in Light Hydrocarbon Recovery Unit

某炼化厂轻烃回收装置的原料为蒸馏装置的三顶不凝气,采用初顶汽油和循环稳定汽油做溶剂从原料气中回收液体产品。2019年6月装置大检修期间,对装置进行腐蚀调查,发现吸收塔塔壁、集油箱、塔盘和溢流堰出现严重腐蚀现象,壳体及内构件材质均为0Cr13Al。结合腐蚀产物对腐蚀机理分析,结果表明:三顶不凝气高H2S含量(v%:3.130)是造成设备腐蚀的主要原因,局部腐蚀速率超过0.5mm/a。针对以上腐蚀原因从设备选材和工艺控制等方面提出了相应的腐蚀控制措施。

The raw material of light hydrocarbon recovery unit in a refinery is the three top non condensable gas of distillation unit.The initial top gasoline and circulating stable gasoline are used as solvents to recover liquid products from the feed gas.During the overhaul of the unit in June 2019,the corrosion of the unit was investigated.It was found that the absorber wall,oil collecting tank,tray and overflow weir were seriously corroded.The shell and internal components were made of 0Cr13Al.The results show that the high content of H2S(v%:3.130)is the main cause of equipment corrosion,and the local corrosion rate is more than 0.5mm/a.In view of the above corrosion reasons,the corresponding corrosion control measures are proposed from the aspects of equipment selection and process control.