Liquid-liquid equilibrium. Computation of liquid-liquid equilibrium in terms of an equation of state

1986 ◽  
Vol 51 (7) ◽  
pp. 1382-1392 ◽  
Author(s):  
Josef P. Novák ◽  
Vlastimil Růžička ◽  
Jaroslav Matouš ◽  
Jiří Pick
Keyword(s):  
Equation Of State ◽  
Thermodynamic Stability ◽  
Boiling Point ◽  
Interaction Parameters ◽  
Liquid Equilibrium ◽  
End Points ◽  
Equilibrium Computation ◽  
First Approximation ◽  
Point Pressure

An algorithm for calculating the boiling point pressure at a chosen temperature and composition was used for computing liquid-liquid equilibrium. A lot of attention is paid to the determination of the first approximation which is specified in terms of the conditions of thermodynamic stability. The conditions of thermodynamic stability make as well possible to localize the lower and upper critical end points (LCEP and UCEP. The Redlich-Kwong-Soave equation of state was applied in calculations, and it was found out that this equation with zero interaction parameters predicts well the lower and upper critical end temperatures in the systems methane-n-hexane, ethane-n-eicosane and ethane-n-docosane.

Excess entropy of the systems of molecules differing in size and shape

1983 ◽  
Vol 48 (1) ◽  
pp. 192-198 ◽  
Author(s):  
Tomáš Boublík
Keyword(s):  
Equation Of State ◽  
Hard Spheres ◽  
Excess Entropy ◽  
Convex Bodies ◽  
Pure Substance ◽  
Liquid Equilibrium ◽  
Simple Rules ◽  
Different Shapes ◽  
The Mean

The excess entropy of mixing of mixtures of hard spheres and spherocylinders is determined from an equation of state of hard convex bodies. The obtained dependence of excess entropy on composition was used to find the accuracy of determining ΔSE from relations employed for the correlation and prediction of vapour-liquid equilibrium. Simple rules were proposed for establishing the mean parameter of nonsphericity for mixtures of hard bodies of different shapes allowing to describe the P-V-T behaviour of solutions in terms of the equation of state fo pure substance. The determination of ΔSE by means of these rules is discussed.

Liquid-liquid equilibrium in the water-ethanol-toluene system. Experimental results

1989 ◽  
Vol 54 (3) ◽  
pp. 581-585 ◽  
Author(s):  
Květuše Říčná ◽  
Jaroslav Matouš ◽  
Josef P. Novák ◽  
Vladimír Kubíček
Keyword(s):  
Distribution Coefficient ◽  
Boiling Point ◽  
Normal Pressure ◽  
Experimental Results ◽  
Azeotropic Mixture ◽  
Liquid Equilibrium

Liquid-liquid equilibrium at 5, 25, and 50 °C was measured in the water-ethanol-toluene system. Special attention was paid to the determination of distribution coefficient of ethanol. Besides, the composition and boiling point of azeotropic mixture at normal pressure were determined.

A modification of the Redlich-Kwong-Soave equation of state and the determination of its parameters on the basis of saturated vapour pressures and second virial coefficients of pure substances

1989 ◽  
Vol 54 (6) ◽  
pp. 1446-1463 ◽  
Author(s):  
Petr Voňka ◽  
Pavel Dittrich ◽  
Josef P. Novák
Keyword(s):  
Equation Of State ◽  
Virial Coefficients ◽  
Effective Algorithm ◽  
Liquid Equilibrium ◽  
Second Virial Coefficients ◽  
Saturated Vapour ◽  
Pure Substances ◽  
Better Than ◽  
Wagner Equation

The temperature dependence of parameter a = a(Tr) of the Redlich-Kwong-Soave equation of state was modified. To calculate the corresponding individual parameters, an effective algorithm applying the Newton method was proposed. The parameters were determined for 60 substances, and the new modification correlates saturated vapour pressures from the values of pr = 0.001 to pr = 1.0 with the accuracy which is usually better than 0.2% and is comparable with that attained in terms of the Wagner equation. The modification proposed is utilized above all when applying the equation of state to the calculation of vapour-liquid equilibrium.

Vapour-liquid equilibrium at low pressures from the back equation of state. II. Ternary systems

1984 ◽  
Vol 49 (5) ◽  
pp. 1240-1246
Author(s):  
Tomáš Boublík
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Ternary Systems ◽  
Liquid Equilibrium ◽  
Pure Compounds ◽  
Benzene Toluene ◽  
Excess Thermodynamic Functions ◽  
Low Pressures

Ternary equilibrium diagrams in the n-hexane-cyclohexane-benzene system at temperature 298.15 K and n-hexane-benzene-toluene system at pressure 101.325 kPa were determined from the BACK equation of state. In the course of the determination of excess thermodynamic functions of mixtures the values of the BACK equation parameters for pure compounds and binary interactions parameters, ki,j, adjusted to GE and HE of the corresponding binaries were employed. The comparison of theoretical and experimental data shows very good quality of the prediction of the equilibrium behaviour of polycomponent systems from the BACK equation of state.

scholarly journals Determination of Vapor-Liquid Equilibrium from Boiling Point Curve

1968 ◽  
Vol 32 (2) ◽  
pp. 149-153,a1 ◽  
Author(s):  
Kazuo Kojima ◽  
Katsumi Tochigi ◽  
Haruo Seki ◽  
Koichi Watase
Keyword(s):  
Boiling Point ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Point Curve ◽  
Vapor Liquid

Modeling of vapor-liquid equilibrium for binary polypropylene glycol/solvent solutions using cubic equation of state models: optimization and comparison of CEoS models

2014 ◽  
Vol 34 (1) ◽  
pp. 95-104
Author(s):  
Ebrahim Ahmadloo ◽  
Najmeh Sobhanifar ◽  
Fatemeh Sadat Hosseini
Keyword(s):  
Equation Of State ◽  
Fluid Mixing ◽  
Polypropylene Glycol ◽  
Mixing Rule ◽  
Liquid Equilibrium ◽  
Bubble Point ◽  
Cubic Equation Of State ◽  
Bubble Point Pressure ◽  
Cubic Equation ◽  
Point Pressure

Abstract The cubic equation of state (CEoS) is a powerful method for calculation of the vapor-liquid equilibrium (VLE) in polymer solutions. Using CEoS for both the vapor and liquid phases allows one to calculate the non-ideality of polymer solutions based on a single EoS approach. In this research, VLE calculations of polypropylene glycol (polypropylene oxide) [PPG(PPO)]/solvent solutions were carried out. In this approach, eight models containing Peng-Robinson-Stryjek-Vera (PRSV) and Soave-Redlich-Kwong (SRK) CEoS separately combined with four mixing rules, namely van der Waals one-fluid mixing rule with one adjustable parameter (vdW1), van der Waals one-fluid mixing rule with two adjustable parameters (vdW2), Wong-Sandler (WS), and Zhong-Masuoka (ZM) were applied to calculations of bubble point pressure. For a better correlation, the adjustable binary interaction parameters existing in any mixing rule were optimized. The results were very acceptable and satisfactory. The results of absolute average deviations (%AAD) between computed results and experimental bubble point pressure data were calculated and presented. Although the capability of two CEoS had a good agreement with experimental data and illustrated the correct type of phase behavior in all cases, the performance of the PRSV+vdW2 was more reliable than the other models.

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