Solubility of CO2 in aqueous solution of MDEA promoted by K2CO3 Experimental investigation and thermodynamic modeling

Abstract

The main objective of this study is to experimentally investigate the CO₂ solubility in an aqueous solution of N-methyldiethanolamine (MDEA) promoted by Potassium carbonate (K₂CO₃) at 303, 313, 323 Kelvin and atmospheric pressure, and to model the behavior of this system. Therefore, it comprises two main sections: experimental and modeling. The experimental section examines and compares the solubility of CO₂ into pure MDEA, pure K₂CO₃, and their mixtures. The results showed that mixed solutions (MDEA 10–30 % promoted by K₂CO₃ 5–10 %) have higher CO₂ solubility compared to pure MDEA and K₂CO₃ at most points. The experiments were carried out using an apparatus for determining gas solubility in liquid (introduced by Pahlavanzadeh et al., 2006, 2009). Based on the data obtained in the experimental section, modeling of the CO₂ solubility into MDEA promoted by K₂CO₃ was performed. The CTS model (introduced by Medeiros et al., 2008, 2013) was used in this study after improvement in the electrolytic section. This model, called CTS^DH, includes three parts: physical, association, and electrolyte. Using the adjustable parameters obtained in this work, the CTS^DH EoS was able to provide relatively good CO₂ loading in a wide range of operating conditions. The average absolute deviation of model results compared to experimental data was determined to be 3.4 %.