Energetics of electrochemically mediated amine regeneration process for flue gas CO2 capture

The electrochemically mediated amine regeneration (EMAR) process presents an alternative route to the conventional thermal regeneration of amines for carbon capture from a flue gas source. In this study, chemical and electrochemical measurements were performed to validate the speciation and activity coefficient models that describe the solution thermodynamics. Electrochemical kinetics and efficiencies were identified and process level energetic calculations were performed using these validated models to understand the effects of various operating parameters on the energy demand for CO2 capture. An isothermal EMAR process requires about 52 kJe/molCO(2), and the net energy demand can be reduced to about 37 kJe/molCO(2) if waste heat is available at temperatures below 90 degrees C. The EMAR process is able to desorb CO2 at pressures up to 20 bar with negligible additional energy penalty. These results suggest that the EMAR process is competitive with the conventional thermally regenerated amine processes. Preliminary assessments also indicate the solvent fomulation with NaCl requires less electric energy among other conventional supporting salt candidates (e.g. Na2SO4) for electrolytic processes. Advanced process designs, process optimization, and the identification of improved solvents may offer the potential to further reduce the energy demand for CO2 capture.