介绍了某石化公司制氢装置低变气换热器6E-4管束泄漏失效情况,通过分析确定管束泄漏是由于0Cr18Ni10Ti不锈钢的应力腐蚀破裂造成的.原因是壳程冷却水含氯离子,管束过热导致结垢严重,垢下腐蚀部位形成应力腐蚀裂纹源,垢下氯离子富集加速了换热管的应力腐蚀开裂.通过材质升级、水质控制和工艺技术改造等措施,确保了该换热器的长周期运行.

The reason of leakage of low-pressure-convert-gas heat exchanger 6E-4 tube bundle in a hydrogen manufacturing plant of a petrochemical company.The results indicated that the essential leakage reason of 6E-4 tube bundle was the stress-corrosion of 0Cr18Ni10Ti austenite stainless steel resulted from Cl- contained in the shell-side cooling water.In addition, the temperature of the cooling water surpassed the normal temperature, resulting in severe scalling.The crack sources were formed from the region of under-scale-corrosion, the chlorine ions were concentrated,and thus the stress-corrosion was speeded up.The means of material quality upgrading,water quality controlling and process technology improvement could ensure long-period operation for the heat exchanger.