重整预加氢进料换热器的腐蚀原因及对策

Cause analysis of corrosion in hydrotreater feed exchanger of CCR and countermeasures

介绍了中国石油克拉玛依石化分公司重整预加氢进料换热器(E-104E)管束的腐蚀泄漏情况,分析了该换热器腐蚀的机理与特征:其主要机理是换热器内部的氯化铵盐结晶以及在换热器低温部位形成了HCl-H2S-H2O循环腐蚀体系;其主要腐蚀特征是孔蚀和应力腐蚀。提出了连续加注缓蚀剂、增设一台高温脱氯器、选择合适的设备材质、设备腐蚀在线监测等防腐蚀措施,其中连续加注缓蚀剂的措施已经得到实践验证,取得良好的效果。

The corrosion leakages were found in the naphtha hydrotreater feed exchanger （E-104E） tubes of CCR in the overhaul in May, 2009 by PetroChina Karamay Petrochemical Company. The corrosion mechanisms and characteristics were studied. The main corrosion mechanisms were the ammonium chloride salt deposition inside the heat exchanger and the formation of HC1 - HzS - H20 corrosion loop at the low - temperature section of heat exchanger. The main characteristics were pit corrosion and stress corrosion. Corrosion protection measures were proposed such as continuous addition of corrosion inhibitor, installation of a high - temperature dechlorinator, selection of appropriate equipment materials and on -line corrosion monitoring of equipment, etc. The continuous addition of corrosion inhibitors has been commercially verified, and good results have been achieved.