| Summary: | 博士 === 國立臺灣大學 === 化學工程研究所 === 84 === Equations of state are widely employed in the calculations of
thermodynamic properties of pure fluids and their mixtures. A
proper mixing model is essential to the equation of state
methods and many researches have been devoted to this respect.
In this study, we developed a new mixing model and applied it
in vapor-liquid equilibrium calculations.Two equations of state
were used in this work: the Peng-Robinson and the Generalized
Flory-Dimer equations. Traditional van der Waals one-fluid
mixing rules were usually used in mixture calculations. This
method has its disadvantage due to the existence of empirical
parameters. In the past twenty years, predictive mixing models
which combine the equations of state and excess Gibbs free
energy models were proposed in literature. This study compared
some of the predictive mixing models in vapor-liquid
equilibrium calculations: the Huron-Vidal, the MHV2, and the
LCVM models. A modification method which determined the energy
parameter of the equation of state by the geometrical average
of the Huron-Vidal and the MHV2 methods was suggested in this
work. The geometrical average approach gave satisfactory
results which are superior to those from the LCVM model.
Recently, the Wong-Sandler mixing model was proposed with
improved theoretical basis where the quadratic mixing rule of
the second virial coefficients was implanted. This study
extended the Wong-Sandler mixing rules by introducing a
coordination number model from statistical mechanics. in nature.
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