碳钢在含硫化氢及高压二氧化碳饱和的NaC1溶液中的腐蚀行为

CORROSION BEHAVIOR OF CARBON STEEL IN HIGH PRESSURE CARBON DIOXIDE SATURATED NaCl SOLUTIONS CONTAINING HYDROGEN SULFIDE

利用自制的高温、高压腐蚀试验及电化学测试装置，通过失重法、电化学极化曲线法及电子探针微观分析等方法，研究了温度、硫化氢浓度对碳钢在高压二氧化碳饱和的３％ＮａＣ１溶液中腐蚀的影响．结果表明：较低温度（８０℃）下，升高温度及增大硫化氢浓度均加速腐蚀反应的阴、阳极过程，失重腐蚀速率增大；高浓度的硫化氢抑制了腐蚀反应的阴极过程；１２０℃时碳钢ＣＯ２腐蚀产物膜对金属基体起很好的保护作用，失重腐蚀速率减小了３－４倍，随硫化氢浓度的增大，失重腐蚀速率缓慢增长，腐蚀产物ＦｅＣＯ３膜逐渐转变为以硫铁化合物为主的腐蚀产物膜．

Using a self autoclave for corrosion testing and electrochemical measurements under high pressure conditions, the effects of temperature and hydrogen sulfide concentration on the corrosion of carbon steel in high pressure CO2 saturated 3% NaCl solutions were studied by weight-loss method, electrochemical polarization technique, electron probe microscopy analysis (EPMA). Experimental results showed that temperature and hydrogen sulfide concentration had obvious effects on the corrosion rate, configuration and character of corrosion scales. The adhesivity and protectivity of corrosion scale formed at lower temperature(80℃ ) were poor. The rising of temperature accelerated cathodic and anodic process of corrosion reaction and at the same time increased corrosion rate. Dense iron carbonate film on steel surface at 120℃, which exhibited good adhesivity and protectivily. The corrosion rate of steel at 120℃ was only one fourth of that at 80℃. Electrochemical polarization indicated that at 120℃ cathodic process of corrosion reaction was accelerated , while the anodic process was restrained. At the lower temperature (80℃ ), both cathodic and anodic process of corrosion reaction were accelerated and the corrosion rate increased with increasing the concentration of hydrogen sulfide. The cathodic process of corrosion reaction is restrained at the higher concentration of hydrogen sulfide. At the higher temperature (120℃ ), with increasing the concentration of hydrogen sulfide the corrosion scale gradually changed from iron carbonate film to corrosion scale mainly made up of sulfur/iron compound. Electrochemical polarization indicated that cathodic process of corrosion reaction was accelerated but the anodic process was restrained.