Corrosion performance of carbon/stainless steel in amine-based solvents under different conditions for CO2 chemical absorption process

The overall corrosion behavior of S304 stainless steel and A3 carbon steel in 30 wt.% MEA (monoethanolamine) and AMP/MEA (2-amino-2-methyl-1-propanol / monoethanolamine) blended amine solutions at 40–100°C was investigated. The characterization analysis of the corroded material surfaces was performed, and the changes in the properties of both solvents after long-term immersion corrosion were measured, including the accumulation of heat stable salts (HSS) and viscosity changes. The results of the long-term immersion corrosion experiments showed that the corrosion rate of S304 stainless steel was significantly lower than that of A3 carbon steel in both amine solutions. However, the corrosion rate of both materials exhibited a similar trend, initially decreasing and then stabilizing over time. Due to the higher concentration of carbonate ions in the AMP/MEA system, it exhibited better overall corrosion resistance and degradation resistance compared to the MEA system. The main component of the corrosion product on carbon steel was identified as Fe₂(OH)₂CO₃. The electrochemical test results showed that the corrosion current of S304 stainless steel was much smaller than that of A3 carbon steel, and its charge transfer resistance was much higher, indicating that it was less prone to electron loss in the organic amine solutions. Additionally, the AMP/MEA system exhibited superior corrosion resistance. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.