加氢裂化热低分气空冷器结盐腐蚀泄漏原因分析

针对加氢裂化装置低分气空冷器腐蚀状况、腐蚀机理和运行工况,结合低分气空冷管束发生泄漏的实际案例,分析计算空冷器的工艺条件以及相关腐蚀数据。通过分析,根据装置进料时氮含量的变化分别计算出氯化铵平衡常数K_p值,结合氯化铵结晶热平衡数据查询出的结盐温度与装置实际运行温度对比,找出结盐的原因及影响因素。采取在A102前定期注水、降低混合进料中的氮含量和空冷管束材质升级等控制措施以达到减缓腐蚀的目的。

Cause Analysis of Salt Corrosion Leakage in Air Cooler of Hot Low-Pressure Separator Gas in Hydrocracking Unit

As for corrosion state, corrosion mechanism and operation condition of air cooler of hot low-pressure separator gas in hydrocracking unit, process condition and corrosion data of cooler were analyzed and collected from practical cases. Equilibrium constant Kp value of ammonium chloride was learnt by the change of nitrogen content while feeding device, salt deposition temperature and operating temperature of unit were compared by heat balance data of ammonium chloride crystallization. Corrective actions were implemented, such as performing regular water injection before A102, reducing nitrogen content of mixed feed and upgrading bundle material.