变换装置混合三通腐蚀失效分析及防护策略研究

Corrosion Failure Analysis and Control Method of Tee on Syngas Pipeline

某变换装置变换炉进气加热器壳程出口冷热粗合成气混合三通腐蚀减薄严重,三通出口端穿孔泄漏,危及装置安全运行。通过现场腐蚀形貌及相关腐蚀机理研究,表明紊流现象造成饱和粗合成气易出现液相,气相中的CO_(2)、H_(2)S溶于水形成碳酸腐蚀和湿H_(2)S腐蚀使得三通腐蚀穿孔泄漏;同时在介质高流速的冲蚀下,三通出口端底部出现明显的流线型沟槽。同时,采用计算机软件对90°三通及45°斜三通流场进行模拟对比分析后发现,45°异径斜三通汇流后主管下游的低速涡流区及湍流强度都明显小于90°异径三通,对下游管壁造成的冲击不明显,混合过程相对平缓,冲刷作用小。最后提出更换三通材料、增加伴热管线以及将90°三通改为45°斜三通三种措施来保证装置的安全运行。

The cold and hot crude syngas mixed tee at the shell side outlet of the converter inlet heater of a converter has been severely eroded.The perforation and leakage at the outlet end of the tee endanger the safe operation of the device.The turbulent flow phenomenon makes the saturated crude syngas prone to liquid phase.CO_(2) and H_(2)S in the gas phase dissolve in water to form carbonic acid corrosion and wet H_(2)S corrosion,which makes the tee corrosion and leakage.There are obvious streamline grooves at the bottom of tee outlet caused by high velocity.This paper uses computer software to compare and analyze the flow field of 90°reducer tee and 45°reducer lateral tee.Finally,three measures are proposed to ensure the safe operation of the device:replacing tee materials,increasing heat tracing pipeline and changing 90°reducer tee to 45°reducer lateral tee.