Institute of Petroleum Engineering

Centre for Gas Hydrate Research Publications

Abstract 162

Freezing Point Depression of Common Electrolyte Solutions: Experimental and Prediction using the CPA Equation of State

Haghighi, H., Chapoy, A., and Tohidi, B.
Industrial and Engineering Chemistry Research, 47, 3983-3989 (2008)

New experimental freezing point depressions of six binary solutions (H2O-NaCl, H2O-CaCl2, H2O-MgCl2, H2O-KOH, H2O-ZnCl2, and H2O-ZnBr2) and four ternary solutions (H2O-NaCl-KCl, H2O-NaCl-CaCl2, H2O-KCl-CaCl2, and H2O-NaCl-MgCl2) have been measured by a reliable differential temperature technique. The available experimental literature data on the freezing point depression in addition to the vapor pressure data of aqueous electrolyte solutions for NaCl, KCl, KOH, CaCl2, MgCl2, CaBr2, ZnCl2, and ZnBr2 have been used to optimize binary interaction parameters between salts and water. The fugacity of water in salt-free aqueous phase has been modeled by the cubic-plus-association (CPA) equation of state. The Debye–Hückel electrostatic term has been used for taking into account the effect of salt on the fugacity of water when electrolytes are present. Model predictions are validated against independent experimental data generated in this work for both single and mixed electrolyte solutions and a good agreement between predictions and experimental data is observed, supporting the reliability of the developed model.

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