Temperature Dependence of Wilson Coefficients: Vapor-Liquid Equilibria of Aqueous Ammonia
Final rept. May-Oct 1999
FORCE TECHNOLOGY LYNGBY (DENMARK)
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This study extends a model for non-ideal solution behavior by considering the temperature dependence of the coefficients of the Wilson equation for aqueous ammonia. Twenty-seven sets of experimental PXY data up to I MPa 10 atm pressure N284 are analyzed using an objective function based on the excess Gibbs free energy to determine the pair of Wilson coefficients for each set. Evaluation of these results supports the interpretation of the interaction parameters in Wilsons equation as temperature dependent entropy functions. Comparison of computed results is made with four categories of vapor-liquid equilibrium VLE data I primary PTXY, 2 refined PTXY, 3 secondary PTXY or PTM, and 4 partial. Excellent agreement is found for all but two of these VLE data sets in the region of rapidly changing vapor composition up to 90 mol of ammonia. A comparison also to three previously published isothermal pairs of Wilson coefficients shows that better agreement in Y for all three cases and in P for two cases is achieved with the entropic representation.
- Physical Chemistry