Comparative study on differently concentrated aqueous solutions of MEA and TETA for CO2 capture from flue gases

Next to IGCC and oxyfuel technology amine scrubbing is one possible process pursued for industrial-scale CO2 capture from power plant flue gases. Aqueous solutions of Monoethanolamine (MEA) are commonly used for the existing amine scrubbing processes because of their high reaction kinetics during CO2 absorption. However, the required energy demand for regeneration of the MEA solution is comparably high, requiring improvements in process technology and solvent development. Within this work the results from lab-scale experimental research on the CO2 absorption from flue gases using differently concentrated aqueous solutions of MEA and Triethylenetetramine (TETA) are presented and discussed. The amine content of the solutions was varied in order to show the influence of concentration on CO2 loading, cyclic capacity and limitations within physical parameters. The equilibrium CO2 loading of the concentrated amine solutions was obtained at temperatures from 30 to 95 °C using synthetic flue gas with different CO2 concentrations of up to 15 vol% CO2. From these results the cyclic capacities of the different solutions are calculated and discussed with focus on the influence of the amine concentration. Furthermore MEA and TETA will be compared on molar and mass basis specifying the significance of TETA as polyamine and its advantages regarding the scrubbing process.

► MEA and TETA solutions were characterized for CO2 capture.
► Concentration, temperature and CO2 partial pressure were varied.
► Total CO2 uptake increases with increasing amine concentration.
► TETA achieves same CO2 uptake than MEA by at least 25% lower concentrations.
► TETA shows potential in reducing CO2 capture costs as alternative to MEA.