Experimental studies on carbon dioxide absorption using potassium carbonate solutions with amino acid salts

Absorption and desorption of CO 2 using K 2 CO 3 solutions promoted by three amino acid salts (AASs), potassium glycinate (PG), potassium lysinate (PL) and potassium L-argininate (PA), were evaluated using 40% CO 2 at 40 °C and with pure N 2 at 80 °C, respectively. The addition of all 3 AASs clearly enhanced both absorption and desorption of CO 2 compared to single K 2 CO 3 solution. PA + K 2 CO 3 solution showed the highest CO 2 cyclic capacity of 0.678 mol CO 2 /mol absorbent, while the highest CO 2 absorption and desorption rates of 39.8 and 17.6 mol CO 2  L −1  s −1 were achieved by PG + K 2 CO 3 solution. Finally, simulated biogas containing 40% of CO 2 and 60% of CH 4 was used as test gas in a hollow fiber membrane contactor. PG and PA promoters presented higher CO 2 absorption flux and removal efficiency than PL promoters in K 2 CO 3 solution within low Gas/Liquid ratio region. Stable CO 2 removal performances for all three promoters were observed at elevated temperature and pressure for 60 min operation.