Low Temperature and High Salt Concentration Effects on General CO₂ Corrosion for Carbon Steel

In this study, the low temperature and high salt concentration effects on CO₂ corrosion have been investigated using electrochemical techniques and weight loss (WL) measurements. The study started with general CO₂ corrosion experiments at low temperatures (1 – 10°C). It was found that the general CO₂ corrosion rate significantly decreased as the temperature decreased. The general CO₂ corrosion rate was found to be under charge transfer control at low temperatures (1 – 10°C). It was also found that the experimental data were not consistent with the data predicted by the most advanced corrosion prediction model.

A series of experiments were also performed to study high salt concentration effects on general CO₂ corrosion. The corrosion rates of carbon steel were found to be significantly affected by the high content of salt. The corrosion rates decrease significantly and nonlinearly with the increase of salt concentration. It was also found from the potentiodynamic results that the high salt concentration retarded the cathodic reaction, the anodic reaction and the limiting current.

A modification to the well known published electrochemical model was made to account for the low temperature and high salt effects. The modified model agrees well with the experimental data at low temperatures and high salt concentrations.