摘要
某石化公司一条石脑油输送管道某弯头部位在停车检验时发现局部存在严重减薄,经切割后发现内壁腐蚀严重并存在多处腐蚀坑.本文拟通过宏观形貌分析、金相组织分析、腐蚀产物微观分析以及腐蚀产物XRD分析等方法对其腐蚀减薄原因进行研究.结果表明,由于输送介质中含有硫、氯等腐蚀性离子,在服役过程中管道内壁发生腐蚀形成腐蚀层,由于局部闭塞效应,诱发小的点蚀坑,导致腐蚀层疏松,发生不定期的剥落,造成管道不断减薄;而在腐蚀产物堆积垢层下由于闭塞效应而发生垢下腐蚀,形成局部的坑状腐蚀.
A certain elbow of a naphtha transportation pipeline of a petrochemical company was found to have severe local thinning during parking inspection.After cutting,it was found that the inner wall was severely corroded and there were multiple corrosion pits.This paper intends to study the reasons for its corrosion thinning through macroscopic morphology analysis,metallographic analysis,microscopic analysis of corrosion products,and XRD analysis of corrosion products.The results show that due to the corrosive ions such as sulfur and chlorine contained in the conveying medium,the inner wall of the pipeline corrodes to form a corrosive layer during the service process.Due to the local blocking effect,small pitting pits are induced,which leads to the loosening of the corrosive layer and irregular spalling-resulting in continuous thinning of the pipeline;and under-scaling corrosion occurs due to the occlusion effect under the corrosion product accumulation scale layer,forming local pit-like corrosion.
作者
湛小琳
闫河
韩利哲
丁敏
李修能
Zhan Xiaolin;Yan He;Han Lizhe;Ding Min;Li Xiuneng(China Special Equipment Inspection and Research Institute,Beijing 100029)
出处
《中国特种设备安全》
2021年第4期94-97,共4页
China Special Equipment Safety
基金
国家重点研发计划(2018YFC0808600)资助。
关键词
垢下腐蚀
电化学腐蚀
腐蚀减薄
石脑油
Corrosion under scale
Electrochemical corrosion
Corrosion thinning
Naphtha
作者简介
湛小琳(1986~),男,硕士,工程师,从事材料腐蚀与防护、失效分析工作;通讯作者:闫河,E-mail:peteryan76@126.com。
