3.4. Effect of regeneration temperatures on regeneration time and
material degradation
Fig. 6 shows the profiles of CO2 desorption from the impregnated AC at various temperatures. For both AC-MEA and AC-DEA, the concentration of CO2 desorbed into the sweeping gas was found to increase with increasing desorption temperatures.
For AC-DEA, the desorption times until no CO2 was detected in the sweeping gas was 60, 50, 40 and 30 min, respectively, for the desorption temperatures of 140, 150, 160 and 170 C. The
temperature of 170 C gave the shortest desorption time for the regeneration of the AC-DEA. For AC-MEA, the desorption times until no CO2 was detected in the sweeping gas was 60 min or longer
when the desorption temperatures were between 140 C and 160 C. The longer desorption times of AC-MEA indicated that mass transfer was hindered more in the AC-MEA than in the AC-DEA. The
desorption temperature of 170 C was not included in Fig. 6a for AC-MEA because after the regeneration of AC-MEA at 170 C, the adsorption capacity of the regenerated AC-MEA was greatly
reduced compared with fresh AC-MEA (Fig. 7a). In contrast, the AC-DEA could be regenerated at 170 C with only a slight drop in the adsorption capacity (Fig. 7b).