Solubility of CO2 in nonaqueous system of 2-(butylamino)ethanol with 2-butoxyethanol: Experimental data and model representation

Abstract

Nonaqueous amine-based system is an attractive solution to overcome high-energy-intensive CO2 capture process using the conventional aqueous amines. Advanced nonaqueous absorbent of 2-(butylamino)ethanol (BAE) with 2-butoxyethanol (2-BE) has been recently proposed for low-energy-consumption CO2 capture. In this work, Henry’s law constants of CO2 in the BAE/2-BE blend were obtained by N2O/CO2 analogy, and correlated in the temperature range of (283–333) K. Vapor-liquid equilibrium (VLE) data for the BAE + CO2 + 2-BE system at 65.4% (mass) BAE were also determined in a stirred equilibrium cell at temperatures of (313–393) K and CO2 partial pressures up to 275 kPa. A single apparent equilibrium constant KCO2,app was proposed for this system and correlated as a function of temperature, carbonated degree of amine and CO2 loading. Solubility data were well represented by the modified Kent-Eisenberg model with an average absolute relative deviation (AARD) of 13%.