Fluid phase equilibria

... 1995) 257267 ilK[ Isothermal vapourliquid equilibrium data for the systems npentane with nhexane, noctane and ndecane Peter Rice, Ali E1Nikheli Dept. ... equilibrium still used was a Lobodest Model 0601 U recirculating still similar to that described by Gutsch and Knapp (1982). ...

An acceleration technique, based on the Dominant Eigenvalue Method of Orbach and Crowe (1971), is proposed to accelerate a successive substitution method in which liquid and vapor compositions are used as the iteration variables. The performance of this scheme is compared with the accelerated successive substitution method of Mehra et al. (1983) and the General Dominant Eigenvalue Method (GDEM) of Crowe and Nishio (1975) as implemented by Michelsen (1982, 1987) which iterate upon the equilibrium ratios. The proposed acceleration scheme exhibits a less oscillatory behavior during convergence, and requires less storage than the accelerated methods using the K-factors as the iteration variables. However, the number of thermodynamic evaluations is comparable with that of Mehra et al. (1983) and is more than that of Michelsen (1982, 1987).On propose une technique d'accélération basée sur la méthode de valeur propre dominante de Orbach et Crowe (1971), pour accélérer une méthode de substitution successive dans laquelle la composition de liquide et de vapeur est utilisée comme variable itérative. On compare la performance de ce schéma à la méthode de substitution successive accélérée de Mehra et coll. (1983) et à la méthode de valeur propre dominante générale (GDEM) de Crowe et Nishio (1975) implantée par Michelsen (1982, 1987). Ces méthodes utilisent les rapports d'équilibre comme variables d'itération. Le schéma d'accélération proposé présente un comportement oscillatoire moins prnoncé pendant la convergence et requiert moins de stockage que les méthodes d'accélération utilisant les facteurs K comme variables d'itération. Cependant, le nombre d'évaluations thermodynamiques est comparable à celui de Mehra et coll. (1983) et est supérieur à celui de Michelsen (1982, 1987).

The Henry's Law constants of CO2, CH4 and N2 in 2701 ionic liquids (ILs) of widely varying structures at (283.15, 298.15, and 323.15) K, the molar volumes and the relative polarity of ILs at 298.15 K are predicted using the thermodynamic method COSMO-RS. Structural variations in the cations and anions that enhance or diminish solubility and selectivity are identified. The trends in Henry's Law constants are explained in the light of molecular interactions qualitatively through sigma profiles and sigma-potentials of ILs. The relationships between the Henry's Law constants and the properties of ionic liquids are also investigated. In general, the Henry's Law constants of CO2 decrease with increase in molar volume, and decrease in polarity of ILs. Both the solubility of CO2 and selectivity decrease as temperature is increased. Activity coefficients at infinite dilution, enthalpies and entropies of solvation are also used to elucidate gas–liquid interactions. COSMOtherm ...

The liquid−liquid equilibria (LLE) data for the
quaternary system, acetic acid, water, p-xylene, and ethyl
acetate, was obtained at 313.15 K under atmospheric pressure.
The composition distribution of each component on the
aqueous phase and organic phase were investigated. To
examine the effects of the solvent, the LLE phase diagrams at
different p-xylene to ethyl acetate ratios are presented for this
quaternary system. The reliability of the tie-line data of this
study was also confirmed using the Othmer−Tobias and Hand
equation. The distribution ratio and separation factors for the
extraction of acetic acid from the aqueous solutions were
obtained. Furthermore, the equilibrium data of this study was
analyzed using the quasichemical activity coefficient (UNIQUAC)
and nonrandom two liquid (NRTL) models. The experimental data was correlated successfully with both the activity
coefficient models that were extended with each binary interaction parameter. To determine the accuracy of each activity model,
the root-mean-square deviations (RMSDs) and average absolute deviation (AAD) resulting from these models were also
calculated. The RMSDs and AAD of the NRTL models were 0.0196 and 0.0213, respectively, whereas those of the UNIQUAC
model were 0.0166 and 0.0114, respectively. These values showed that the UNIQUAC model is superior to the NRTL model.

The comprehensions of Roger Boscovich (1711-1787) concerning the structure of fluids have been further developed applying the achievements and the results of modern science. It is shown that various supermolecular rotating particles (molecular pairs, bimolecules and oligomolecules) exist in compressed gases and liquids. The volumes occupied by rotating particles are equal to the volumes of substances at the critical point (molecular pairs), co-volume of van der Waals equation (bimolecules), and volume of solid phase at triple point (oligomolecules). A mathematical model that enables the calculation of these volumes as well as their fractions in liquids was developed. The importance of the supermolecular structure of olefins and vinyl monomers for their polymerization is presented.

Isothermal vapor-liquid equilibrium (VLE) data for binary mixtures of tert-butanol + glycerol have been measured at the temperature range from (318.15 to 328.15) K using a simple quasi-static ebulliometer. The reliability of this apparatus was verified by comparing the measured vapor pressures of tert-butanol with the published data. The comparisons showed that our data were in good agreement with the published data with average absolute deviations in the vapor pressures of 0.48%. For the VLE data measurements of tert-butanol + glycerol, the bubble point vapor pressures increased with increasing tert-butanol mole fractions. The experimental data were correlated by using the Wilson, Non-Random Two-Liquid (NRTL), and Universal Quasi-Chemical (UNIQUAC) activity coefficient models with an average absolute deviation of 3.44%, 3.44%, and 3.42%, respectively.

Density (ρ) and viscosity (η) values of the binary mixtures of phenetole+ 1-pentanol,+ 1-hexanol,+ 1-heptanol,+ 1-octanol,+ 1-nonanol, and+ 1-decanol over the entire range of mole fraction at 293.15, 298.15, 308.15, and 318.15 K have been measured at atmospheric ...