An electrochemical model for prediction of corrosion of mild steel in aqueous carbon dioxide solutions
An electrochemical model for prediction of corrosion of mild steel in aqueous carbon dioxide solutions
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DOI：
10.5006/1.3293640
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发表时间：
1996-04-01
期刊：
影响因子：
1.6
通讯作者：
Olsen, S
中科院分区：
文献类型：
--
作者：
Nesic, S;Postlethwaite, J;Olsen, S
基于水-CO2体系中单个电化学反应的建模，建立了均匀二氧化碳（CO2）腐蚀的预测模型，该模型考虑了氢离子（H+）还原、碳酸（H2CO3）还原、直接水还原、氧还原和铁的阳极溶解等电化学反应。通过在玻璃电池中进行的实验，确定了不同反应的交换电流密度和塔菲尔斜率。通过极化电阻、动电位扫描、电化学阻抗和失重测量来监测腐蚀过程。该模型针对两种低碳钢在一系列参数上进行了校准：温度(t) = 20℃至80℃，pH = 3至6，CO2分压(p -CO2) = 0 bar至1 bar (0 kPa至100 kPa), omega = 0 rpm至5,000 rpm （v(p) = 0 m/s至2.5 m/s）。该模型适用于无保护膜的均匀腐蚀。通过将预测结果与独立回路实验结果进行比较，验证了模型的性能。预测结果还与其他CO2腐蚀预测模型进行了比较。与以往的主要经验模型相比，该模型考虑了pH、温度和溶液流速对参与的阳极和阴极反应的影响，从而更清晰地描述了腐蚀机理。
A predictive model was developed for uniform carbon dioxide (CO2) corrosion, based on modeling of individual electrochemical reactions in a water-CO2 system The model takes into account the electrochemical reactions of hydrogen ion (H+) reduction, carbonic acid (H2CO3) reduction, direct water reduction, oxygen reduction, and anodic dissolution of iron The required electrochemical parameters (e.g., exchange current densities and Tafel slopes) for different reactions were determined from experiments conducted in glass cells. The corrosion process was monitored using polarization resistance, potentiodynamic sweep, electrochemical impedance, and weight-loss measurements. The model was calibrated for two mild steels over a range of parameters: temperature (t) = 20 degrees C to 80 degrees C, pH = 3 to 6, partial pressure of CO2 (P-CO2) = 0 bar to 1 bar (0 kPa to 100 kPa), and omega = 0 rpm to 5,000 rpm (v(p) = 0 m/s to 2.5 m/s). The model was applicable for uniform corrosion with no protective films present. Performance of the model was validated by comparing predictions to results from independent loop experiments. Predictions also were compared to those of other CO2 corrosion prediction models. Compared to the previous largely empirical models, the model gave a clearer picture of the corrosion mechanisms by considering the effects of pH, temperature, and solution flow rate on the participating anodic and cathodic reactions.