Hot potassium carbonate (PC) solution in comparison with amine solution had a decreased energy of regeneration and a high chemical solubility of CO2. To present vapor and liquid equation (VLE) of this system and predict CO2 solubility, the ion specific non-electrolyte Wilson-NRF local composition model (isNWN) was used in this study; the framework of this model was molecular. Therefore, it was suitable for both electrolyte and non-electrolyte solutions. The present research employed the NWN model and the Pitzer-Debye-Hückel theory in order to assess the contribution of the excess Gibbs energy of electrolyte solutions in a short and long range. The data of CO2 solubility in water and the system of aqueous K2CO3 were correlated in the model considering a temperature range of 10 − 170 ○C and a pressure range of and 0.5 − 141.1 bar. The average absolute error of (CO2 − H2O) and (CO2 − H2O − K2CO3) systems were 4.2% and 11.41% respectively. The results and comparisons with other models proved that the experimental data were exactly correlated in the model.

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