A consistent and transferable thermodynamic model to accurately describe CO2 capture with monoethanolamine

•Postcombustion CO2 absorption in MEA is accurately described with the soft-SAFT EoS.•Amine and alcohol groups are characterized independently.•Thermodynamic model valid in a wide range of pressure, temperature and CO2 loading.•The phase behavior and absorption enthalpy of CO2 in MEA are well captured.•The model is transferable to predict the absorption capacity of other alkanolamines.

In this work, a consistent and transferable thermodynamic model to describe the carbon dioxide (CO2) capture process with monoethanolamine (MEA) has been successfully developed within the framework of the soft-SAFT equation of state. The effect of the association interactions of the amine and alcohol groups contained in MEA have been isolated and characterized by studying the 1-alkylamines and 1-alkanols family. In a similar manner, the interaction between these functional groups and water has also been determined and later transferred to aqueous MEA. At the end, a reliable and consistent set of molecular parameters has been obtained for MEA. The CO2 absorption process is described in terms of the aggregation of the reactants driven by the presence of strong intermolecular interactions. Descriptions of the density, vapor pressure and surface tension in these systems provide excellent agreement with the available experimental information. Also, a very good estimation of the CO2 loading in MEA is found in the range of operating conditions. Predictions on the mixing enthalpies and the enthalpy of absorption are also given. This transferable model will allow the prediction of the CO2 absorption process in other alkanolamines in the absence of experimental data.

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