Density and Viscosity Measurements and Modeling of CO2-Loaded and Unloaded Aqueous Solutions of Potassium Lysinate

This paper reports new experimental data and calibrated semiempirical correlations concerning the density and viscosity of aqueous solutions of potassium lysinate (LysK), a promising bio-based solvent for postcombustion CO2 capture from flue gases, an application of relevance for industrial decarbonization. The analysis covers a LysK molality range in the solution from 2.16 to 4.44 molLysK/kgH2O, temperature intervals between 288.15 and 358.15 K, and a CO2 loading range of 0.3-0.98 molCO2/molLysK. Newly collected experimental results supported the development and calibration of semiempirical correlations for the density and viscosity of LysK solutions suitable to predict these thermophysical properties in the range of conditions tested. These models can predict the behavior of the thermophysical properties investigated with high accuracy (for loaded solutions, average absolute deviation for density equal to 1.48 kg/m3 and for viscosity of 0.04 mPa s) within the whole range of LysK concentration, temperature, and CO2 loading explored. Validation against literature data lying outside the calibration range shows an accuracy for density correlation ≤3%, while for the viscosity model, deviations are larger and vary between 1 and 15% of the measured value.