渣油加氢装置汽提塔顶空冷器的腐蚀泄漏分析

Corrosion Leakage Analysis of Stripper Air Cooler in Residue Hydrogenation Unit

针对A炼油厂渣油加氢装置汽提塔顶空冷器(EA-3001)管束首端焊口腐蚀泄漏状况,展开了检测和分析研究,明确了管束端部胀口铵盐聚集形成垢下腐蚀是造成泄漏的原因。汽提塔上部及其冷凝冷却系统发生腐蚀的原因在于自反应系统来的反应产物中一般含有H2S,NH3和Cl-等腐蚀性介质,通过加氢反应形成NH4HS和NH4Cl,在温度压力降到一定程度结晶析出,再加上工艺操作引起管束偏流以及露点腐蚀,导致了空冷EA-3001发生铵盐腐蚀泄漏。建议严格控制原料中的氮含量,改善空冷器前注水措施,调整好注入量,以减少铵盐的生成,保证装置的安全稳定运行。

Detection and analysis were carried out in the light of leakage situation at pipe welding head of stripper air cooler(EA-3001) in residue hydrogenation unit of a refinery, the results showed that the leakage problem was incurred by under-deposit corrosion. The corrosion was mainly caused by NH4HS and NH4Cl formed from corrosive media such as H2S, NH3 and Cl- contained in reaction products. Measures are proposed to ensure long-term operation of the unit, such as strictly controlling nitrogen content in raw material, improving water injection measures of air cooler, adjusting injection amount to reduce ammonium salts.