Studies on corrosion and corrosion inhibitors for amine based solvents for CO2 absorption from power plant flue gases containing CO2, O2 and SO2

AbstractThis work investigated the effects of operating parameters on the corrosion of carbon steel in MEA- H2O-CO2-O2-SO2 systems. It also investigated the effectiveness of a number of chemical additives in inhibiting corrosion. Two methods, namely, the Tafel plot and potentiodynamic polarization techniques were used to quantify the corrosion rate. The results showed that an increase of both O2 and SO2 concentrations in simulated flue gas stream, CO2 loading, MEA concentration and the operating temperature induced higher corrosion rates. Also, the data obtained from different corrosion measurement techniques produced almost the same results. In addition, the corrosion products obtained experimentally based on CE and SEM/EDS measurements included Fe(OH)2, Fe(OH)3, 2Fe2O3⋅H2O, FeCO3, and FeSO4. A power-law model shows that CO2 loading had the highest impact on the corrosion rate, while SO2 and O2 show only slight effects on the corrosion rate. I was observed that all of the corrosion inhibitors tested can minimize corrosion of carbon steel in the MEA- H2O-CO2-O2-SO2 system. However, the inhibition efficiency of each inhibitor depended on its concentration