New AMP/polyamine blends for improved CO 2 capture: Study of kinetic and equilibrium features

2‐Amino‐2‐methyl‐1‐propanol (AMP), which is the sterically hindered form of monoethanolamine (MEA), is a credible substitute to conventional CO 2 ‐capturing solvents. Its performance can be improved by blending with a highly reactive polyamine promoter. Two such aqueous blends of AMP/TETA and AMP/TEPA were chosen here (TETA = triethylenetetramine and TEPA = tetraethylenepentamine). The kinetics of CO 2 absorption in the proposed blends was investigated at 308, 313, and 318 K using the stirred cell technique. The concentrations of AMP and polyamine were varied between 2 to 3 kmol/m 3 and 0.1 to 0.5 kmol/m 3 , respectively. From the measured values of the fast pseudo‐first order constants, the second‐order rate constants for the reactions of CO 2 with TETA (14 695 m 3 /(kmol s)) and TEPA (19 250 m 3 /(kmol s)) were determined at T = 313 K. Both TETA and TEPA react faster with CO 2 than MEA. Further, the respective activation energy values were found (40 and 37 kJ/mol). Finally, the equilibrium solubility of CO 2 for both blends was measured at T = 303 K. The loading capacity was higher than that for the aqueous blends of AMP/MEA, AMP/DEA, and AMP/MDEA (here, DEA and MDEA denote diethanolamine and N‐methyldiethanolamine). The highest value of loading capacity (1.12 mol CO 2 /mol amine at 2.01 kPa equilibrium partial pressure of CO 2 ) was noted in AMP/TEPA mixtures. The new findings on our proposed blends will strengthen the AMP/polyamine application in CO 2 separation.