湿CO_(2)环境中316不锈钢腐蚀行为研究

Corrosion behavior of 316 stainless steel inwet CO_(2) environment

针对CO_(2)管输过程中碳钢因发生腐蚀而导致失效的问题,开展了316不锈钢的腐蚀行为研究。使用失重法研究含水率、CO_(2)分压以及Cl-浓度对316不锈钢腐蚀行为的影响,并绘制了腐蚀特征图谱;采用扫描电镜分析了腐蚀产物的微光形貌,X-射线衍射仪分析了腐蚀产物成分。结果表明:316不锈钢在管输CO_(2)工况条件下表现出较好的耐腐蚀性,处于轻度腐蚀状态,腐蚀速率极低;316不锈钢腐蚀速率随含水率的增大而增大,随CO_(2)分压的增大而减小,随Cl-浓度的增加而增大;316不锈钢含有Cr可以在不锈钢表面形成致密的钝化膜,这使得Cr成为不锈钢防腐的关键;由于316不锈钢腐蚀速率远小于碳钢,在腐蚀“重灾区”,可以考虑将集输管道更换成316不锈钢。该研究成果为CCUS中CO_(2)管输钢材的选型提供重要的理论依据。

To solve the problem that carbon steel is prone to corrosion during CO_(2) pipeline transportation,the corrosion behavior of 316 stainless steel was studied.The effects of water content,CO_(2) partial pressure and Cl-concentration on the corrosion behavior of 316 stainless steel were studied by weight loss method,and the corrosion characteristic map was drawn.The low-light morphology of corrosion products was analyzed by scanning electron microscope,and the components of corrosion products were analyzed by X-ray diffractometer.The results show that 316 stainless steel shows good corrosion resistance under the condition of CO_(2) pipeline transportation,and it is in a mild corrosion state with extremely low corrosion rate.The corrosion rate of 316 stainless steel increases with the increase of water content,decreases with the increase of CO_(2) pressure,and increases with the increase of Cl-concentration.Cr is the most effective element to prevent corrosion in 316 stainless steel,which can form a dense and extremely thin passivation film on the metal surface.Because the corrosion rate of 316 stainless steel is much lower than that of carbon steel,it can be considered to replace the gathering pipeline with 316 stainless steel in the“hardest hit area”of corrosion.The research provides an important theoretical basis for the selection of CO_(2) pipeline steel in CCUS.