Corrosion issues of MDEA solutions

The main corrosion mechanisms are as follows: 1. R2NH-H2S-CO2-H2O corrosion: This type of corrosion is primarily caused by CO2; both free and combined forms of CO2 can lead to corrosion. Severe corrosion occurs in areas at high temperatures with the presence of water (above 90°C), such as in the regeneration tower and its feed pipelines, as well as in the bottom reboiler and its inlet and outlet pipelines. Furthermore, pollutants present in the amine solution play a significant role in accelerating the reaction between steel and CO2, such as heat-resistant amine salts, oxygen, and solids. 2. Amine stress corrosion cracking: The factors that affect amine stress corrosion cracking include the type of amine, the composition of the amine solution, the temperature of the metal, and the level of tensile stress. Amine stress corrosion generally occurs in amine-poor solutions containing low concentrations of acidic gases; fresh amine solution does not suffer from amine stress corrosion. Amine stress corrosion cracking is unlikely to occur in amine-rich solutions containing high concentrations of acidic gases; in such solutions, other types of stress corrosion cracking are more common, such as SSC and HIC/SOHIC. 3. Carbonate corrosion cracking: This refers primarily to the cracking that occurs in metals in an alkaline acidic water environment containing moderate to high concentrations of carbonates, as a result of the combined effects of tensile stress and corrosion. The main influencing factors are pH value, carbonate concentration, and tensile stress level