This study dealt with the prediction and correlation of vapor-liquid equilibria behavior of nonideal fluids. The thermodynamic formalism of the GE-EoS models, which combines the two traditional methods gamma-phi and phi-phi used so far for low and high pressure phase equilibria correlations respectively, has been combined with the 1FGE model, based on one-fluid theory, to produce a more consistent approach to the phase equilibrium problem. In the first part of our study we examine the predictive abilities of our model for vapor-liquid equilibria of highly nonideal fluids. The results establish the fact that the Huron-Vidal mixing rule with a one parameter version of the lFGE model, is able to successfully utilize available experimental information at low pressures for phase equilibria predictions of multicomponent mixtures over an extended range of pressures and temperatures. In the second part of the study we perform an analysis of the correlative abilities of the 1FGE model, as applied to hydrogen-hydrocarbon mixtures. The results of this part suggest that the unique local composition character of the 1FGE model, along with its one size and one temperature-dependent energy parameter, make it able to adequately describe vapor-liquid equilibria behavior of multicomponent mixtures for this highly asymmetric class of mixtures. Moreover, it is shown that the model parameters for binary hydrogen-hydrocarbon mixtures can be correlated to the acentric factor of the hydrocarbon. The important class of the refrigerant mixtures was modeled in the third part of this study. The lFGE model was introduced into the Wong-Sandler mixing rule, based on the infinite pressure state thermodynamic formalism. The results for these systems showed that a limited amount of experimental data, either at low or high pressures can be utilized to provide a parameter which is practically independent of the temperature set used. As shown from the results, this single parameter can be used to extend vapor-liquid equilibria predictions over a range of conditions for this difficult class of systems. More importantly, we set a heuristic rule able to screen multiparameter and one parameter models. A coordination temperature-parameter planet can be used as a predictive tool from a limited amount of information. Our model comes in lieu of the GE models based on two-fluid theory, which are inconsistent with the one fluid character of an EoS. The 1FGE-EoS framework proposed in this work meets current needs in the area of Applied Thermodynamics, which require that the model's parameters can be obtained from a limited information of experimental data and can give for accurate phase equilibria predictions of nonideal mixtures from low to high pressures.

Reviews the latest developments in a subject relevant to professionals involved in the simulation and design of chemical processes - includes disk of computer programs.

Working Guide to Vapor-Liquid Phase Equilibria Calculations offers a practical guide for calculations of vapor-phase equilibria. The book begins by introducing basic concepts such as vapor pressure, vapor pressure charts, equilibrium ratios, and flash calculations. It then presents methods for predicting the equilibrium ratios of hydrocarbon mixtures: Wilson's correlation, Standing's correlation, convergence pressure method, and Whitson and Torp correlation. The book describes techniques to determine equilibrium ratios of the plus fraction, including Campbell's method, Winn's method, and Katz's method. The remaining chapters cover the solution of phase equilibrium problems in reservoir and process engineering; developments in the field of empirical cubic equations of state (EOS) and their applications in petroleum engineering; and the splitting of the plus fraction for EOS calculations. - Includes explanations of formulas - Step by step calculations - Provides examples and solutions

The prediction or correlation of thermodynamic properties and phase equilibria with equations of state remains an important goal in chemical and related industries. Although the use of equations of state has for a long time has been restricted to systems of simple fluids, there is an increasing demand for models that are also suitable for complex and macromolecular compounds. Due to its ability to describe the thermodynamics of symmetric as well as asymmetric systems, the most common approaches for modeling gas-polymer solubility have been based on the PC-SAFT EOS. It has wide applicability starting from low molecular weight organic compounds to highly non-ideal macro-molecular weight system such as polymer In the present work, PC-SAFT equation of state of Gross & Sadowski, 2001 has been used to model solubility of various gases /vapors in liquid polyethylene to demonstrate the suitability of PC-SAFT EOS for polymer-solvent system.

Vapor-Liquid Equilibria Using UNIFAC: A Group-Contribution Method focuses on the UNIFAC group-contribution method used in predicting quantitative information on the phase equilibria during separation by estimating activity coefficients. Drawing on tested vapor-liquid equilibrium data on which UNIFAC is based, it demonstrates through examples how the method may be used in practical engineering design calculations. Divided into nine chapters, this volume begins with a discussion of vapor and liquid phase nonidealities and how they are calculated in terms of fugacity and activity coefficients, respectively. It then introduces the reader to the UNIFAC method and how it works, the procedure used in establishing the parameters needed for the model, prediction of binary and multicomponent vapor-liquid equilibria for a large number of systems, the potential of UNIFAC for predicting liquid-liquid equilibria, and how UNIFAC can be used to solve practical distillation design problems. This book will benefit process design engineers who want to reliably predict phase equilibria for designing distillation columns and other separation processes.

Vapor-Liquid Equilibrium, Second Edition covers the theoretical principles and methods of calculation of equilibrium conditions from various experimental data and the elements of measuring technique, as well as the instruments for the direct determination of the equilibrium compositions of the liquid and vapor phases of the system. The book discusses the relations necessary for the thermodynamic treatment of the equilibrium between the liquid and vapor phase of a system; the concept of an ideal solution and auxiliary thermodynamic functions; and the activity and the activity coefficient. The text also describes vapor-liquid equilibrium in real systems (electrolytes and non-electrolytes) and in systems whose components (i.e. temperature, pressure, and composition of phases) mutually react according to several stoichiometric equations. The criteria of purity of substances and the methods of measuring temperature; low, medium, and high pressures; the pressures of the saturated vapors at given temperatures; and the boiling points at given pressures used in laboratory work in the field of vapor-liquid equilibrium are considered. The book also tackles the methods for the direct determination of equilibrium data (distillation, circulation, static, dew and bubble point, and flow methods). The text concludes with a review of the literature on the systems whose vapor-liquid equilibrium data had been measured and reported to the beginning of 1954. Workers in the chemical industry who deal with problems of distillation and rectification will find the book useful.