Corrosion performance of A3 carbon steel in 30wt.% MEA and AMP-MEA blends for post-combustion carbon capture: Effect and mechanism of corrosion inhibitors.

• Corrosion behavior of A3 carbon steel was evaluated by using both electrochemical testing techniques (potentiodynamic polarization technique and electrochemical impedance spectroscopy [EIS]) and immersion corrosion experiment (weight loss method) in 30 wt.% MEA and AMP-MEA blend amine solution systems. • The inhibition effect and mechanism of imidazoline, sodium metavanadate (NaVO3) and phosphoric acid, triethanolamine salt (P-TEA) in these two solvent systems were studied. • With the three inhibitors added, the Tafel curves exhibited varying degrees of rightward shift, indicating an increase in corrosion potential. NaVO3 and P-TEA could effectively raise the solution resistance and charge transfer resistance, thus achieving a corrosion inhibition effect. • AMP-MEA blends exhibits improved corrosivity performance with formation of a denser Fe2(OH)2CO3 protective layer on the surface of A3 carbon steel compared to MEA system at 100 °C. This could be illustrated by the higher bicarbonate concentration in AMP-MEA system. • The HSS and iron ion content of two solvent systems showed no significant difference and the HSS concentration order was sulfate > oxalate > glycolate > formate > acetate. The corrosion behavior of A3 carbon steel in 30 wt.% MEA and AMP-MEA (2:1) blended amine solutions, two typical CO 2 capture solvents for chemical absorption processes, was investigated. The inhibition effects of imidazoline, sodium metavanadate (NaVO 3), and phosphoric acid, triethanolamine salt (P-TEA) were evaluated using various electrochemical testing techniques and immersion corrosion experiments. Results showed that NaVO 3 exhibited the highest corrosion inhibition effect at a concentration level of 1000 ppm, while imidazoline showed limited effectiveness. Both NaVO 3 and P-TEA significantly increased solution resistance and charge transfer resistance, thereby enhancing corrosion inhibition. Additionally, AMP-MEA blends exhibited improved corrosion performance compared to MEA, with the formation of a denser protective layer on the surface of A3 carbon steel. Furthermore, experimental results revealed that NaVO 3 and P-TEA, instead of forming protective oxide or carbonate layers, formed complexes or chelates with iron ions in the solution. These compounds adsorbed onto the carbon steel surface, effectively preventing further corrosion. These findings provide valuable insights into the corrosion behavior of A3 carbon steel in amine-CO 2 H 2 O systems and underscore the potential of NaVO 3 and P-TEA as effective corrosion inhibitors. This knowledge is crucial for developing enhanced corrosion control strategies in related industrial applications. [ABSTRACT FROM AUTHOR]