Water-lean blend mixtures of amino acid salts and 2-methoxyethanol for CO2 capture: Density, viscosity and solubility of CO2

Abstract

Water-lean amino acid salt (AAS) solutions have attracted special attentions for energy-efficient CO2 absorbents. In this work, 2-methoxyethanol was proposed as a novel anti-solvent due to its excellent properties such as low volatility, low specific heat capacity and low viscosity. Density and viscosity were measured at atmospheric pressure for water-lean blends of potassium sarcosinate (SarK) or potassium L-prolinate (ProK)/water/2-methoxyethanol over the temperature range from (293 to 353) K and the AAS molality up to 4.914 mol·kg−1. Partially CO2 loaded solutions were also investigated. Equilibrium solubility of CO2 in AAS/water/2-methoxyethanol solutions was measured in a stirred equilibrium cell at temperatures of (313, 333 and 373) K and CO2 partial pressures up to 190 kPa. These property data were correlated using empirical correlations as a function of AAS molality, CO2 molality and/or temperature. The predicted values of density and viscosity matched well with the measured data, with AADs within 0.31% for density and 3.76% for viscosity. The solubility data of CO2 were fairly fitted with a proposed Soft model.