Chabab, Salaheddine, Théveneau, Pascal, Corvisier, Jérôme, Coquelet, Christophe, Paricaud, Patrice, Houriez, Céline, and Ahmar, Elise El
• CO 2 solubility in NaCl brine was measured with equipment based on the static-analytic method. • The PR-CPA model was extended to electrolytes (e-PR-CPA). • The Soreide and Whitson model was improved. • The well-known Duan model and a geochemical model implemented in the CHESS/HYTEC software were tested. • Evaluation of the models were done over a wide range of temperature, pressure and molality. The thermodynamic study of the CO 2 -H 2 O-NaCl system is of great importance whether in an environmental context as part of Carbon Capture and Storage (CCS) or in an economic context such as enhanced oil recovery by CO 2 injection, or massive and reversible underground storage for industrial use (methanation, fermentation, water treatment, carbonation of drinks, etc.). In this work, using a new set-up based on the "static-analytic" method, measurements of CO 2 solubility in aqueous sodium chloride solution were performed at molalities between 1 and 3 m, at temperatures between 50 and 100 °C and pressures up to 230 bar. For the modeling part, an electrolyte version of the PR-CPA (Peng-Robinson Cubic Plus Association) equation of state was developed under the name "e-PR-CPA", as well as modified Soreide and Whitson (m-SW) model was used and improved. These two models using the phi-phi approach are compared with two geochemical models (Corvisier 2013 and Duan el al. 2006) using the gamma-phi approach, and against the literature and measured data. The measured data are in good agreement with the literature data and model predictions. Under geological storage conditions, the e-PR-CPA and Duan models estimate solubility slightly better (Average Absolute Deviation less than 6.6%) than the m-SW model and the geochemical model (AAD less than 7.6%). [ABSTRACT FROM AUTHOR]