冷低压分离器油相系统铵盐垢下腐蚀风险的模拟预测

SIMULATION AND PREDICTION OF CORROSION RISK UNDER AMMONIUM SALT SCALE IN COLD LOW PRESSURE SEPARATOR OIL PHASE SYSTEM

为探究某加氢装置高压换热器管束腐蚀泄漏原因,利用Aspen Plus工艺模拟软件计算了冷低压分离器油相(简称冷低分油)中水质量分数分别为1%,2%,3%时,冷低分油系统的露点温度、氯化铵结晶温度、氯化铵潮解点温度和相对湿度。结果表明:相较于经验的露点温度预测方法,通过引入潮解点、划分系统“湿环境”温度范围判断氯化铵垢下腐蚀风险区域的方法与实际腐蚀案例更为切合;在3种油相含水条件下,换热器管束存在氯化铵垢下腐蚀的“湿环境”温度范围分别为:50~103℃,50~161℃,50~176℃;随着油相中含水量的提高,“湿环境”腐蚀区域逐渐向高温部位迁移,预计铵盐导致的垢下腐蚀将会愈加严重。

In order to explore the reasons for the corrosion failure and leakage of the high-pressure heat exchanger tube bundles of a hydrogenation unit,the dew point temperature,ammonium chloride crystallization temperature,ammonium chloride deliquescent temperature and relative humidity of the cold low pressure separator oil phase stream were calculated by Aspen Plus process simulation software when the water mass fractions were 1%,2%and 3%.It is found that compared with the empirical dew point temperature prediction method,the method of judging the corrosion risk area under ammonium chloride scale by introducing the deliquescent point and dividing the“wet environment”temperature range is more suitable for actual corrosion cases.The“wet environment”areas are determined as 50-103℃,50-161℃and 50-176℃in the case of 3 kinds of oil phase water content,respectively.In addition,with the increase of water content in the oil phase,the corrosion area in the“wet environment”will gradually migrate to the high temperature part,and the ammonium chloride salt corrosion is expected to become more severe.