氢气压缩机级间冷却系统二氧化碳腐蚀与防护

Carbon dioxide corrosion and protection of hydrogen compressor interstage cooling system

苯乙烯装置氢气压缩机级间冷却系统的腐蚀主要集中在一至四级气体冷却器壳体底部和壳程出口管线弯头等部位,具有坑蚀、沟槽状腐蚀及台地状腐蚀等典型的CO_(2)局部腐蚀形貌特征。在CO_(2)腐蚀环境中,因金属表面各区域FeCO3腐蚀产物膜覆盖度不同而形成了电偶腐蚀,对氢气压缩机级间冷却系统的设备及管道造成了腐蚀,其中奥氏体不锈钢设备及管道腐蚀轻微,而碳钢设备及管道则腐蚀严重。冷却系统的工艺、温度和压力等影响因素为CO_(2)腐蚀的发生及发展提供了环境条件。针对该系统的腐蚀原因及机理,提出了定期排污和加注气相中和缓蚀剂的防护措施。

The corrosion of hydrogen compressor interstage cooling system in the styrene plant was mainly concentrated at the bot⁃tom of the shell of the first to fourth stage gas cooler and the elbow of the shell side outlet line,with typical characteristics of CO_(2)local corrosion morphology such as pit corrosion,groove corrosion,and platform corrosion.In the CO_(2)corrosion environment,galvanic corrosion was formed due to the different film coverage of FeCO3 corrosion products in various areas of the metal surface,which corroded the equipment and pipelines of the hydrogen compressor interstage cooling system.CO_(2)caused mild corrosion to austenitic stainless steel equipment and pipelines,while severe corrosion to carbon steel equipment and pipelines.The process,temperature and pressure of the cooling system provided environmental conditions for the occurrence and development of CO_(2)cor⁃rosion.According to the corrosion causes and mechanism,protection measures of periodic blowdown and adding inhibitors were proposed.