Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Amino acid salts have potential use as alternative absorbents to alkanolamines for post combustion CO2 capture, because of their negligible volatility, resistance to oxidative degradation and fast absorption rates. In this work, the density and viscosity of CO2-free and CO2-loaded aqueous solutions of potassium lysinate (LysK) and potassium prolinate (ProK)were measured at temperatures from (298.15 to 348.15)K and for their concentrations from (0.2 to 3.0) mol L 1. The data were correlated accurately (R2 0.99) as a function of temperature, concentration and CO2 loading by nonlinear regression analysis. The solubility of CO2 in 2.5 mol L 1 amino acid salt solutionswas also determined in vapor liquid equilibrium vessels at temperatures (313 and 333) K and CO2 partial pressures relevant to flue gas conditions. It was found that, the CO2 absorption capacity of LysK is higher than that of industrially used monoethanolamine (MEA) and the CO2 loadings vary as LysK greater than ProK greater thanMEA at given CO2 partial pressures. Moreover, LysK may offer higher cyclic loading than MEA for CO2 capture.