Study of mixing rules on equation of state

• Main Authors: Yo-Li Chou, 周有利
• Other Authors: Yan-Ping Chen
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/21486238956458944766

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.