Absorption Of CO₂ From Flue Gas Into Activated SG Solutions

Chemical absorption of CO2 from flue gases has been extensively studied in recent years because of both environmental concern of greenhouse effect and carbon dioxide's great potential as resources. Features of sodium glycinate (SG) solutions activated by piperazine (PZ), the interaction of amines in solution, kinetics region, as well as regeneration behavior were studied in this paper, which may serve future study as groundwork.In the present work absorption of CO? into aqueous blends of SG and PZ has been studied at the total concentration of 1.0 kmol·m-3 in a double stirred-cell contactor. The relationships between the absorption rate, absorption capacity and absorption time were analyzed. The results indicated that a small addition of PZ into SG solutions increases the absorption rate and that aqueous blends of SG and PZ are much more suitable as flue-gas CO2 scrubbers than other traditional alkanolamines such as monoethanolamine (MEA).The interactions of SG and PZ in aqueous solutions were observed at the temperature of 313 K. As for the blends with 0.1,0.2, 0.3 kmol·m-3 PZ, the Enhancement Factors remain above 80% of their original values at the CO2 loading of 0.1. It was demonstrated that the kinetics region of absorpting CO2 into aqueous blends of SG and PZ belongs to the fast pseudo-first order reaction regime.The regeneration capability of the aqueous blends of SG and PZ was investigated by heating under various operating conditions. Experimental results showed that the most suitable regeneration temperature for the blends of SG and PZ is 388 K. It was found that the blends of 0.9 kmol·m-3 SG + 0.1 kmol·m-3 PZ has the highest regeneration efficiency under our experiment conditions, namely 91.0%, which is 2.6% higher than single SG The fast absorption rate combined with high regeneration efficiency suggest that aqueous solutions of SG activated by PZ have the potential to be a preferred solvent for CO2 capture.