N2-bubbling Method for O2 Removal from the Loaded MEA Solution in the CO2 Capture Process

Flue gas stream contains full-oxidized (carbon dioxide), partially oxidized hydrocarbons, and some extent of oxygen. Carbon dioxide can be separated by CO2 capture and separation (CCS) process using monoethanolamine (MEA). In this process, CO2 accompanied with O2 can be absorbed by the solution (MEA+H2O). Dissolved molecular oxygen may explicitly participate in the cathodic reaction and generate sever corrosion problems, or it may induce amine degradation via irreversible oxidative reaction, reducing amine efficiency. In this research, the method of N2-bubbling was investigated for deoxygenation of loaded aqueous MEA solution on a laboratory scale. N2-bubbling set-up was simulated with a known volume glass vessel in which bubbling of N2 with an available flow rate was applied through the loaded amine solution. A mathematical formula was developed to correlate the N2-bubbling flow rate, F, the volume of amine solution in the bubbling column, V, and time taking the oxygen concentration decreases from saturated O2-solution to less than 0.5 mg/L.