Investigation into the Mechanistic Controlling Behaviors of CO₂ Corrosion Models via the Use of Simulated Polarization Curves

In this work, a comprehensive mechanistic model for CO₂ corrosion is investigated in detail to explore the underlying electrochemical behavior. Simulated polarization curves are generated under different environmental and hydrodynamic conditions by varying the carbon dioxide (CO₂) partial pressure, and the velocity of the bulk flow. The electrochemical response is examined using these curves and compared with output corrosion data to perform in-depth analysis as to underlying causes of the model behavior. Regions of charge-transfer control and mass-transport control are clearly identified and discussed in relation to the chemical and electrochemical reactions occurring in the system. Hence, the degree of sensitivity of the corrosion rate to changing conditions is analyzed with respect to these controlling mechanisms. Under full mass-transport control, the corrosion rate increased significantly with increasing pressure and velocity, however under charge-transfer control the corrosion rate was independent of either variable, demonstrating some potentially counter-intuitive relationships between changes in operating environment and corrosion rate response.