氯苯装置腐蚀原因分析及预防措施

Corrosion Cause Analysis and Prevention Measures of Chlorobenzene Unit

某炼厂氯苯装置现场腐蚀调研发现副产盐酸单元管道、法兰、设备外壁、结构框架和楼板均发生严重外部腐蚀。结合装置选用材质、设备表面温度、当地的气候环境对腐蚀原因进行了分析。结果表明:氯苯装置外部腐蚀是大气腐蚀引起。氯苯装置内部工艺介质含有氯化氢或者盐酸,部分露到周围的大气中,并溶于低温设备管道表面的薄液膜或者水膜,形成pH值较低的盐酸溶液,腐蚀设备、管道、螺栓的外壁。针对氯苯装置外部腐蚀严重的原因,提出了相应的预防建议和处理措施。

The on-site corrosion investigation of chlorobenzene unit in a refinery found that serious external corrosion occurred on the pipes,flanges,equipment outer walls,structural frames and floors of the by-product hydrochloric acid unit.The corrosion causes were analyzed based on material selection,surface temperature and local climate environment.The results show that the external corrosion of chlorobenzene plant is caused by atmospheric corrosion.The process medium inside the chlorobenol device contains hydrogen chloride or hydrochloric acid,which is partially exposed to the surrounding atmosphere and dissolves in the thin liquid film or water film on the surface of the pipeline of the low-temperature equipment,forming hydrochloric acid solution with low pH and corroding the outer wall of the equipment,pipeline and bolt.In view of the serious external corrosion of chlorobenzene plant,the corresponding prevention suggestions and treatment measures are put forward.