Showing papers in "Fluid Phase Equilibria in 1983"

TL;DR: In this article, the authors investigate various aspects of the density-dependent local composition (DDLC) concept and offer two useful forms, one for the Peng-Robinson (1976) equation of state and the other for the non-ideal mixtures.

TL;DR: Group contribution methods for dense fluid (liquid) mixtures are critically reviewed in this paper, where emphasis is placed on common sense rather than on mathematical derivations, and the purpose of the review is to stimulate discussion.

TL;DR: In this paper, the equation recently proposed by Chrastil was modified to correlate solubility of solids and liquids in supercritical carbon dioxide and ethylene for a total of 37 systems.

TL;DR: In this paper, the UNIFAC group contribution method was used to synthesize molecular structures with specific solvent properties for the separation of aromatic and paraffinic hydrocarbons, and the potential solvents were studied with regard to their solvent power, selectivity and binodal curve.

TL;DR: In this paper, a method for determining the enthalpy of hydrogen-bond formation and the equilibrium association constant for pure liquid compounds is presented, based on an association model derived from Flory's theory of mixtures of polymers.

TL;DR: In this paper, infinite dilution partial molal volumes have been measured for heavy organic solids in supercritical fluid solvents and compared with some of the common cubic equations of state as well as for an ideal chemical theory approach.

TL;DR: For equimolar mixtures at 298.15 K, deviations from ideality range from 0.46 J ·mol −1 for n -hexane to 23.16 J·mol − 1 for 2,2-dimethylbutane.

TL;DR: In this paper, a continuous distribution function instead of the mole fractions of individual components is used to establish a consistent building of "continuous thermodynamics", which can be applied to the phase equilibria of all mixtures containing a large number of similar chemical species as heavy petroleum fractions, similar coal-derived liquids, tars and polymers.

TL;DR: In this paper, a new equation of state which contains four parameters and remains cubic in terms of volume has been developed and successfully applied to the representation of properties of pure components (compressibility factor, fugacity coefficient, enthalpy departure, vapor pressure, and saturated liquid and vapor volumes) and mixtures (vapor-liquid equilibria and compressibility factor).

TL;DR: In this paper, phase equilibria of the second type are found in fluid (n-alkane + water) mixtures (gas + gas) of the first type.

TL;DR: In this article, the authors describe a new model for strong, completely dissociated electrolytes in pure and mixed solvents based on the UNIQUAC model, which can represent binary water/salt systems up to salt concentrations of 10 mol/kg water for 1:1 salt and 6.5 mol.kg for 2:1 salts.

TL;DR: In this paper, an associated-solution theory was proposed for the self-association of methanol and solvation equilibrium constants between unlike molecules, and the results were analyzed using an associated solution theory.

TL;DR: In this article, the authors introduce the concepts of universality, critical exponents, scaling laws, field and density variables, "strong" and "weak" directions, and present experimental evidence for the presence of nonclassical critical behavior in fluids and fluid mixtures.

TL;DR: In this paper, a method of modifying empirical equations of state in order to improve their performance in the critical region is introduced, which involves the construction of a state function which measures the effective distance between the state in question and the critical state, and a mathematical transformation, parameterized by this function, is then used to define a new equation of state which is designed to be identical in behavior to the original formulation outside the critical regions, but to develop the nonclassical scaling behavior characteristic of real fluids near the critical point.

TL;DR: In this paper, a statistical-mechanical thermodynamic formalism for polydisperse fluids is presented, the starting point for which is the distribution of the differences of the chemical potentials of the species to that of an arbitrarily chosen component.

TL;DR: In this article, the translation concept of the equation of state as a function of the nature of the components and of the problem at hand is used to adapt the mixing law to polar mixtures.

TL;DR: In this paper, the solubility of components of low volatility having the same vapour pressures at 70 °C -hexadecanol, octadecane and salicylic acid phenyl ester - in various gases and entrainers have been determined.

TL;DR: In this article, the UNIFAC group-contribution method was used to predict the solubility of some gases of industrial importance in pure solvents and solvent mixtures.

TL;DR: In this article, the analysis and acceleration of the successive substitution algorithm for two-phase flash calculations, phase envelope computations, phase stability analysis and multiphase flash and related problems are reviewed.

TL;DR: In this article, the phase behavior of North Sea oils and gas condensates is predicted using only six hydrocarbon fractions, and the experimental results are simulated using the SRK equation of state and a suitable characterization procedure based on analytical information.

TL;DR: In this article, the utility of perturbed hard sphere equations of state based on a simplified Barker-Henderson theory for a square well fluid inclusive of the three-body contributions is examined for orthobaric densities and both sub- and supercritical isotherms of simple fluids.

TL;DR: In this paper, two high pressure phase equilibrium cells working according to the analytical method in the temperature range 300 to 450 K and up to 200 MPa have been developed, where p,T,x,y equilibrium data can be determined by sampling and GC analysis.

TL;DR: In this paper, a cubic equation of state is developed based on the concept of perturbation theory to include the rotational contribution of molecular motion in addition to the repulsive and attractive contributions.

TL;DR: In this article, the mean-field two-component lattice gas model was improved by introducing interacting surface areas and an empirical entropy of mixing parameter, which has proven to be well capable of describing almost quantitatively fluid-phase behaviour of non-polar and polar substances of low and high molar mass and mixtures thereof in large temperature and pressure ranges.

TL;DR: In this article, the statistical-mechanical basis for the local-composition model is presented, where local compositions are expressed in terms of the potential of mean force, so that the approximations required to obtain the expressions commonly utilized can be analyzed and new and improved expressions can be developed.

TL;DR: Mollerup et al. as mentioned in this paper proposed a new random-non-random-mixture equation for the Helmholtz energy of a fluid mixture, which combines the van der Waals random mixture theory with the nonrandom liquid theory of the local composition concept.

TL;DR: In this article, the static dielectric constant of water and the freon R22 (CHClF2) is shown in some detail, and the PVT-data of concentrated supercritical aqueous NaCl-solutions and the ion product of pure water to 1000 °C are discussed.

TL;DR: In this article, supercritical acetone or methanol extraction of wood gave liquid products with a maximum yield of 74%. Approximately 5% of these complex products were identified as substituted guaiacols and levoglucosan.

TL;DR: In this paper, a thermodynamically consistent method has been developed for the quantitative characterization of vapor-liquid equilibria in systems with electrolytic components and mixed non-electrolytic solvent.

TL;DR: In this article, sixteen two-term three-parameter equations of state were evaluated and compared from the viewpoint of suitable representation of properties at saturation and in the high liquid density region (ρ r ≤ 3) of pure components.