尿素装置CO_2汽提塔腐蚀原因分析  

Corrosion Causes Analysis for CO_2 Stripper of the Urea Unit

作　　者：张辉[1] 魏盛斌 赵光辉 王文灿 关好 

机构地区：[1]中国石油乌鲁木齐石化设备检验检测院,新疆乌鲁木齐830019

出　　处：《石油化工设备》2014年第A01期87-90,共4页Petro-Chemical Equipment

摘　　要：针对某石化公司化肥厂尿素装置CO2汽提塔衬里、分布管及换热列管上均发现有大量的裂纹和腐蚀坑缺陷的问题,通过对设备材质进行宏观检查、金相分析、扫描电镜分析、硬度测试以及腐蚀产物成分分析等方法对相关缺陷的产生原因进行分析,认为导致该设备发生大量裂纹性缺陷的原因是在局部无氧条件下,双相不锈钢受介质中含有的N-甲基二乙醇胺(MDEA)、硫离子、氰酸根离子的作用产生具有选择性腐蚀特征的氢致应力腐蚀开裂。Serious corrosion problems happened in CO2 stripper of a urea plant, a large number of cracks and pitting corrosion were observed in the lining, gas tube and heat exchanging pipe. After macroscopically testing, micro-structure analysis, scanning electron microscope analysis, hardness testing and chemical composition analysis, the result show that the root failure reason is hydrogen induced stress corrosion cracking with a selective corrosion characteristics for duplex steel, which were caused by oxygen free condition and the medium containing MDEA, S ion and CN.

关 键 词：尿素装置 CO2汽提塔 腐蚀 双相不锈钢 N-甲基二乙醇胺(MDEA) 

分 类 号：TQ050.1[化学工程]