X65管线钢在油水两相界面处的CO2腐蚀行为研究

Corrosion Behavior of X65 Pipeline Steel at Oil-Water Interface Region in Hyperbaric CO2 Environment

利用失重法、电化学极化法、电化学阻抗谱及腐蚀形貌观察和腐蚀产物物相分析,研究了油水分层介质中X65管线钢在油水两相界面处的腐蚀行为及不同缓蚀剂在油水界面处的作用效果。结果表明,在CO2分压为0.9 MPa,温度为60℃,静止状态下的油水分层介质中,X65钢在油相区几乎不发生腐蚀,在油水两相界面处发生局部腐蚀,在水相区发生严重腐蚀。添加水溶性缓蚀剂十七烯基胺乙基咪唑啉季铵盐使得X65钢在该工况下的腐蚀速率降低,添加油溶性缓蚀剂癸硫醇反而使得X65钢在油水两相界面处的局部腐蚀加重,甚至出现了腐蚀沟槽。

The corrosion behavior of X65 pipeline steel at oil-water interface region in hyperbaric CO2 environment was studied by means of weight loss method,polarization curve,electrochemical impedance spectroscopy and other electrochemical analysis techniques,as well as corrosion morphology observation and corrosion products analysis.The results revealed that the X65 steel had little corrosion in the oil phase,local corrosion occurred at the interface region between oil and water,severe corrosion occurred in the aqueous region,where the oil-water stratified medium was under stationary state with CO2 partial pressure of 0.9 MPa at 60℃.The addition of seventeen alkenyl amide ethyl imidazoline quaternary ammonium salt,which is water soluble rust inhibitor,could reduced the corrosion rate of X65 steel under this condition,while the addition of the decyl mercaptan,which is oil soluble rust inhibitor,could aggravated the local corrosion of X65 steel at the oil-water interface,whilst,groove corrosion was observed at the oil-water interface.