The prediction of Thermodynamic-Kinetic behavior of anti solvent crystallization from Sodium Chloride aqueous systems containing Non-electrolytes

In this study, the antisolvent crystallization system containing sodium chloride as solute, water as primary solvent and ethanol as the antisolvent was considered. At first there was a saturated solution of water-NaCl, by gradual addition of ethanol in a specific rate, the solubility of NaCl decreases. A thermodynamic model which can predict the behavior of the aqueous salt systems containing non-electrolytes was applied in this study. This model consists of a Gibbs energy function, which combines a Debye-Hückel term with the standard UNIQUAC model. Using the Extended UNIQUAC model for the purpose of thermodynamic modeling, the solubility of NaCl in the water-ethanol mixture in different compositions with an acceptable error was calculated. The model parameters including volume, surface area and binary interaction parameters were modified by comparing the experimental and theoretical data of NaCl solubility in water-ethanol mixture. Afterwards, this thermodynamic solubility model was introduced to the kinetic modeling of antisolvent crystallization process using Population Balance Equation. Using supersaturation for the calculation of the nucleation and the crystal growth rates, crystal size distribution and the volume mean of crystals were determined by the numerical solution to the PBE implementing Discretization technique. In order to evaluate the model accuracy, antisolvent addition rates were changed and the results were compared with the experimental data, the results appeared justifiable.