二氧化碳环境中碳钢电偶腐蚀行为研究  

GALVANIC CORROSION BEHAVIORS OF CARBON STEEL UNDER CARBON DIOXIDE (CO_2) ENVIRONMENT

作　　者：刘东[1] 艾俊哲[1] 郭兴蓬[1] 

机构地区：[1]华中科技大学化学系

出　　处：《天然气工业》2007年第10期114-116,共3页Natural Gas Industry

基　　金：国家自然科学基金(编号:50471062)资助项目

摘　　要：电偶腐蚀是油气开采运输过程中危害性较大的一种腐蚀。利用失重法和电偶电流测量以及扫描电镜和X衍射分析研究了饱和CO2的1%NaCl水溶液中碳钢/不锈钢,以及碳钢/腐蚀产物膜之间的电偶腐蚀行为。结果表明,相同温度条件下,碳钢/不锈钢电偶对阴阳极面积比越大,电偶对中阳极(N80钢)的腐蚀速率就越大。当CO2分压较低时(0.1MPa),随着温度的升高,电偶对阳极的腐蚀速率有一个极大值,且腐蚀速率的对数值与阴阳极面积比的对数值之间呈线性关系;而在高CO2分压(2.5MPa)条件下,阴阳极面积比小于等于4时,电偶对阳极的腐蚀速率存在一个极大值和一个极小值。试验结果还表明,温度对碳钢的CO2腐蚀产物组分有很大的影响,不同温度下碳钢表面形成的腐蚀产物膜都能与裸金属之间形成腐蚀电偶,且温度为90℃时生成的腐蚀产物膜与碳钢的电偶腐蚀最为严重。Galvanic corrosion is one of the most harmful corrosion during the exploration and transportation of oil and gas.The corrosion behaviors of the couples between the carbon steel and stainless steel as well as between the carbon steel and corrosion product scales of 1 percent NaCl water solution of the saturated CO2 were studied by means of the weightlessness method,galvanic current measurement,scan electron microscope and X diffraction.The results showed that under the same temper-ature condition,the bigger the Sc/a,of the carbon steel/stainless steel to the cathode and anode is.the higher the Vcorr couple to anode(N80 steel)will be.When the CO2 fractional pressure is relatively low(less than 0.1 MPa),the said VTO has a maximum value as the temperature keeps rising and the logarithm value of Vcorr has a linear relationship with the logarithm value of Sc/a.Under the condition of high CO2 fractional pressure(2.5 MPa).the said Vcorr has a maximum value and minimum value whenn the Sc/a.is less than or equate 4.The test result all showed that temperature has great influences on the CO.corrosion products' components of carbon steel.The corrosion product scales on the surface of the carbon steel under different temperatures can form corrosion galvanic couple with the bare metals.When the temperature is 90℃,the bimetallic corrosion of the corrosion product scales and carbon steel is most serious.These researches can provide significant references to the prevention of bimetallic corrosion.

关 键 词：二氧化碳腐蚀 电化腐蚀 低碳钢 不锈钢 腐蚀产物 实验室试验 

分 类 号：TE980[石油与天然气工程—石油机械设备]