The Phase Equilibrium Calculation Of Solution Containing Electrolyte

The electrolyte solution widely exist in industrial processes, life science andnature, for example the Extraction and distillation of salting out with salt bath anddesalination membrane desalination process, The development and utilization of saltlake resources, so the thermodynamic properties research of electrolyte solution hasimportant theoretical significance and value in industry.Organic solution system containing salt appeared in the process of manychemical industry, for example: the extractive distillation, Received widely attentiondue to salt effect undermine its constant boiling, other like the heat pump technology,there is a kind of working medium is LiBr-H2O-CH3OH, also have many similarworking medium, so to study thermodynamic properties of the solution containingorganic and salt system has important significance for salt effect and distillationseparation.Based on phase equilibrium problems for several different types of systemscontaining electrolytes, puts forward several new calculation method and a newthermodynamic model.1. Based on the gibbs can minimize the method to calculate phase equilibriumprinciple，sea water and alkaline water system which the phase behavior and phasenumber are unknown. Combinated minimizing gibbs free energy method and thegenetic algorithm, established one step mathematical model for calculating of thephase behavior and composition.2. Using the principle of Henry’s law and dissolution equilibriumthermodynamics, established mathematical model to calculate KCl-HCl-NaCl- H2O three-phase equilibrium, and applied genetic algorithm to the optimal solutionin the process of solving calculation.3. In view of the uniquac model can’t be used well in the organic solutioncontaining salt application problems,so this work put forward a new extendeduniquac model, the influence of salt concentration in organic phase activitycoefficient is introduced into the model of the formula, and the salt-alcohol-watersystem and the salt-alcohol-alcohol system of gas liquid equilibrium wascalculated.4.As to the pitzer model in organic mixed solution can not associated with theexperimental data very well, put forward new pitzer extension model, fitting out theorganic composition ‘s influence the expression of the relative model parameters, andused the corresponding thermodynamic data, calculated the solid liquid equilibriumof inorganic salt5. The pitzer and Li Yigui&Pitzer’s simplified model is applied to calculate thephase equilibrium at elevated temperature, this work improved the applicability of themodel, and the HCl-H2O system and FeCl2-HCl-H2O system’s phase equilibriumat elevated temperature was calculated.