Effect of the concentration of MAPA on the heat of absorption of CO2 and on the cyclic capacity in DEEA-MAPA blends

In this work, the heat of absorption of CO2 in aqueous blends of 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA) were measured as a function of CO2 loading at 40 °C, 80 °C and 120 °C. The main objective was to investigate the effect of concentration of MAPA on the heat of absorption. Furthermore, from the total pressure measurements the partial pressure of CO2 was estimated and cyclic capacities were calculated. The study included systems forming one and two liquid phases during CO2 absorption. The results show that increasing the concentration of MAPA in a 3 M DEEA solution raised the heat of absorption at all temperatures. Similarly the cyclic capacity increased with the rise of MAPA content in 3 M DEEA blends. However, increasing the MAPA concentration up to 5 M and simultaneously decreasing the DEEA concentration to 1 M, decreased the cyclic capacity.