Equilibrium solubility measurement and Kent‐Eisenberg modeling of CO2 absorption in aqueous mixture of N‐methyldiethanolamine and hexamethylenediamine

Abstract Vapor‐liquid equilibrium of CO 2 in aqueous mixture of hexamethylenediamine (HMDA) and N‐methyldiethanolamine (MDEA) has been investigated using a stirred equilibrium cell set‐up in the temperature and pressure range of 303–333K and 1–100kPa, respectively. Composition of the mixed amine solvents used are (5mass% HMDA+25mass% MDEA), (10 mass% HMDA+20 mass% MDEA), (15mass% HMDA+15mass% MDEA), and (20 mass% HMDA+10 mass% MDEA). Equilibrium solubility data is fitted using the Kent‐Eisenberg thermodynamic model. To fit experimental solubility data with model predicted data, bicarbamate formation and zwitterion deprotonation reaction equilibrium constants of HMDA are regressed as a function of CO 2 loading and temperature. Average absolute deviation between experimental and model predicted data is found to be 7.16%. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.