An increasingly popular approach when solving the phase and chemical equilibrium problem is to pose it as an optimization problem. However, diiculties are encountered due to the highly nonlinear nature of the models used to represent the behavior of the uids, and because of the existence of multiple local solutions. This work shows how it is possible to guarantee-global solutions for a certain ...

The Gibbs tangent plane criterion has become an important tool in determining the quality of obtained solutions to the phase and chemical equilibrium problem. The ability to determine if a postulated solution is thermodynamically stable with respect to perturbations in any or all of the phases is very useful in the search for the true equilibrium solution. Previous approaches have concentrated ...

The liquid-liquid equilibrium (LLE) phase boundaries were determined experimentally for the ternary systems containing refined sunflower oil, methanol, and one of ten potential cosolvents at 308.2 K under atmospheric pressure by using cloud point method. n-Butylamine was found to be one of the best cosolvents, which could substantially enhance the miscibility between the oil and methanol. The L...

A concentration-dependent surface area parameter model (Iwai, Fluid Phase Equilibria, 465 (2018) 24–32) was modified to avoid the restriction conditions for parameters of pure components. The is applied correlate ternary liquid-liquid equilibria and constituent binary phase with one set parameters. correlated results both vapor-liquid obtained by are better than those NRTL UNIQUAC models. simul...

Isobaric vapor–liquid equilibrium (VLE) data for 2-propanol + 1-butanol, 2-propanol + 1-pentanol, 1butanol + 1-pentanol and 2-propanol + 1-butanol + 1-pentanol were measured at 101.3 kPa by using an improved Rose still. All the binary VLE data have passed the traditional area test proposed by Herington. The interaction parameters for the Wilson, NRTL and UNIQUAC equations were determined by reg...

In process simulation, reliable and accurate property estimation methods play an important role in the solution of various simulation problems where convergence is often traced to failures in the reliable predictions of physical and thermodynamic properties. Convergence and reliability of the simulation is heavily dependent on the fluid package selected. Predictions of phase equilibrium using v...

This paper reports experimental data and the thermodynamic modeling of the liquid-liquid equilibrium systems with triacylglycerols, free fatty acids (obtained from olive oil), ethanol and water. The experimental data were fitted using the UNIQUAC model, in which absolute deviation of 1.28 % and root mean square deviation of 2.10 % between experimental and calculated mass fraction of the compone...