Experimental Measurement and Thermodynamic Modeling of CO2 Absorption in a Wide Range of Aqueous MDEA Solutions (10-98 wt%)

In this study, the process of capturing CO2 by using an aqueous MDEA solution under the operating conditions of the concentration range of 10-98 wt% of MDEA, temperature range of 303-323K and atmospheric pressure is investigated. Most researchers have measured the effect of pressure changes on the loading, but in this work, we have investigated the effect of changing the concentration of amine on the loading. We employed the apparatus introduced by Pahlavanzadeh et al. to evaluate the solubility of carbon dioxide in the aqueous solutions of N-methyldiethanolamine (MDEA). The results indicate that the maximum absorption of CO2 takes place in concentration of between 40-50 wt% of MDEA. Subsequently, the Cubic-Two-State Equation of State (CTS EoS) was improved and used to describe the solubility of CO2 in aqueous MDEA solutions in a wide range of concentrations and temperatures. This equation, referred to as CTSDH, includes three terms relating to the different intermolecular interactions happening in electrolyte solutions. The same EoS was used for vapor and liquid phases. Model parameters were adjusted according to the experimental results of this work and other researches. Using the adjustable parameters from this work, the model successfully approximated CO2 loading under a wide range of functional conditions. The evaluation of model results with experimental data showed the average absolute percent deviation (AAD%) to be 7.05%, indicating a satisfactory alignment between model predictions and Measured results.