Polarization Behavior and Performance of Inorganic Corrosion Inhibitors in Monoethanolamine Solution Containing Carbon Dioxide and Heat-Stable Salts

This work has extended the knowledge of corrosion inhibition by sodium metavanadate (NaVO₃) and copper carbonate (CuCO₃) in the carbon dioxide (CO₂) separation process using aqueous solutions of monoethanolamine (MEA). The inhibition behavior and performance of these two inhibitors were examined using the electrochemical polarization technique in a 5-kmol/m³ MEA saturated with CO₂ at 80°C. The results showed that NaVO₃ generally offered superior inhibition performance over CuCO₃. The performance of both inhibitors deteriorated when the heat-stable amine salt represented by oxalate was present in the solution. The CuCO₃ was found to induce some pitting tendency but NaVO₃ did not.