Density and Viscosity of Potassium and Sodium Glycinate Solutions

Among the features of solvents, density and viscosity are essential to consider in the design of new absorption facilities and estimate properties such as diffusivity. In the present work, the density and viscosity of potassium glycinate aqueous solutions and sodium glycinate aqueous solutions [4–40 wt %] have been measured from 288.15 to 323.15 K. From these data, it can be concluded that potassium glycinate solutions are less viscous (by 16.5% on average for 1.0 mol/kg solvent) than sodium glycinate solutions. A comparison with other solutions of amino acid salts leads to the conclusion that glycinate solutions have relatively low viscosities, which can reduce the capital and operating costs of carbon dioxide (CO2) capture facilities. To enable viscosity and density to be estimated accurately, three semi-empirical correlations are set up to correlate the viscosity of potassium and sodium glycinate solutions. These correlations are compared and provide accurate results of viscosity (AARD < 3.1%). Density is also correlated, and the correlation shows excellent results (AARD < 0.2%).