(181b) A Comprehensive Thermodynamic Model for the Lithium Chloride and Water Binary System Using the Electrolyte NRTL Model

Thermodynamic properties of the lithium chloride and water binary system have been extensively studied, however, many of these analyses are applicable only to a narrow range of concentration and/or temperatures. The objective of the present work is to establish a comprehensive thermodynamic representation by implementing the symmetric electrolyte NRTL (eNRTL) activity coefficient model. The solubility model correlates the nonideality of the solution with the composition dependency by utilizing two binary interaction parameters for each of the electrolyte-electrolyte and molecule-electrolyte pairs in the system. Each parameter is determined by applying up to three temperature dependent coefficients and then regressed from experimental data. This allows the parameters to establish the accuracy of the model for concentrations up to saturation and temperatures between 273.15-473.15 K. The advancement of process design, optimization, and operation range of absorption heat pumps and refrigeration systems, as well as the increasing interest in understanding the phase behavior of lithium salt systems for energy storage devices facilitates the need for a comprehensive thermodynamic model.