制氢装置水分器三通开裂原因分析

Failure analysis of tees in water separator of hydrogen generation plant

分析了某炼油厂制氢装置水分器三通的腐蚀开裂原因,认为在高温工况时,失效构件的高温蒸汽腐蚀诱发的应力腐蚀占主导地位,它破坏了不锈钢表面氧化膜的保护性并产生腐蚀微裂纹,冲刷和气蚀及二氧化碳腐蚀起加剧作用;在低温工况时,氢致开裂占主导地位,进一步使裂纹扩展直至开裂;各种腐蚀形式交互影响,加剧了水分器三通的腐蚀开裂失效。通过工艺流程动改,取消了三通部件,彻底消除了该部位存在的腐蚀开裂隐患。

The analysis of corrosion cracking causes of a tee in water separator of a hydrogen generation plant concluded that the stress corrosion induced by water vapor corrosion of the failed component was predominant under the high-temperature conditions. The damage of protection film and corrosion cracking on the stainless steel surface, erosion, cavitation corrosion as well as carbon dioxide corrosion accelerated the corrosion process. Under the service conditions of low temperature, hydrogen induced cracking （HIC） was predominant, which further propagated the micro-cracks to cracking. In addition, the interactions of different corrosions have aggravated the corrosion failure of the separator. The potential safety hazard of corrosion cracking was thoroughly eliminated by process modifications and cancel of the tees.