柴油加氢改质装置分馏塔顶空冷器腐蚀分析及对策

Analysis and Countermeasures of Air Cooler Corrosion at the top of Fractionation Tower of Diesel Hydro-upgrading Unit

某石化公司1.5 Mt/a柴油加氢改质装置在运行过程中分馏塔顶空冷器多次出现泄漏,严重影响装置安全平稳长周期运行。通过对空冷器管束进行涡流检测、塔顶露点计算和管束内锈垢分析,结果表明原料中的氯及反应产物中未经汽提塔完全脱除的H_2S及NH_3均会导致分馏塔顶空冷器腐蚀。根据腐蚀机理,提出原料氯离子监控预警,加注缓蚀剂、空冷器管束冲洗、冬季防冻措施优化、加强设备腐蚀监测及优化工艺操作等防腐蚀措施和建议。

A number of corrosion leakage emergencies occurred in the overhead air cooler of 1. 5 Mt/ a diesel hydro-upgrading unit at CNPC Karamay Petrochemical Company, which seriously affected the safe, stable and long?term operation of the device. By means of eddy current testing, fractionation tower top dew point calculation and rust element analysis in the tube bundle, the results showed that the corrosion was caused by the chlorine in the raw materials, as well as the H 2 S and NH 3 in the reaction product. According to the corrosion mechanism, the anti?corrosion measures and optimization suggestions were proposed, such as chloride ion monitoring and early warning, adding slow release agent, air cooler tube bundle flushing, winter antifreeze measures optimization, strengthening equipment corrosion monitoring and optimizing pre-process operation.