Electrochemical Investigation on the Effect of Heat-stable Salts on Corrosion in CO2 Capture Plants Using Aqueous Solution of MEA

Amine treating plants have long encountered the problem of solvent degradation associated with nonregenerable heat-stable salts. This work investigated the effect of six heat-stable salts on corrosion of process equipment made of carbon steel 1018 and stainless steel 304. The investigation was done by conducting electrochemical corrosion experiments in a 5 kmol/m^3 aqueous solution of monoethanolamine (MEA) at 80 °C under 0.20 mol/mol CO2 loading. The results show that heat-stable salts caused the solution corrosiveness to increase to various degrees, depending upon type and concentration of salt. Oxalate was the most corrosive, followed by malonate and formate. No salts induced pitting corrosion on either test material.