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 ...

Following the work of Austgen et al., the electrolyte nonrandom-two-liquid (NRTL) model was applied in a thermodynamically consistent manner to represent the vapor-liquid equilibrium (VLE) of the aqueous monoethanolamine (MEA)-CO2 system with rigorous chemical equilibrium consideration. Special attention was given to the accurate VLE description of the system at both absorbing and stripping con...

The interaction energy parameters of the Nonrandom two-liquid (NRTL) equation for Bi–Se, Pb–Se, Sb–Se, and Tl–Se binary systems were determined. difference in goodness fit between was discussed each system. activities components at corresponding temperatures four calculated using NRTL equation. mixing enthalpies Gibbs free energies these obtained. calculations are agreement with experimental da...

Isobaric vapor–liquid equilibria of the binary mixtures toluene + styrene at 30 and 40 kPa α-methylstyrene 20 25 were measured applying a recirculation still. The equilibrium data modeled adopting non-random two-liquid (NRTL) excess Gibbs energy model with RK (Redlich–Kwong) equation state. NRTL interaction parameter optimization was carried out employing own literature for system. applied corr...

Ionic liquids (ILs) have been suggested as potential "green" solvents to replace volatile organic solvents in reaction and separation processes due to their negligible vapor pressure. To develop ILs for these applications, it is important to gain a fundamental understanding of the factors that control the phase behavior of ionic liquids with other liquids. In this work, we continue our study of...

The adequate correlation of experimental phase equilibrium data by using any thermodynamic model represents a key point for the rigorous design chemical processes. However, this process remains challenging problem, due to high nonlinearity models used and consequent problems convergence. present work analyzes nonrandom two-liquids mode (NRTL) check relation between values binary interaction par...

Several approaches have been proposed for the computation of solutions to the phase and chemical equilibrium problem when the problem is posed as the minimization of the Gibbs free energy function. None of them can guarantee convergence to the true optimal solution, and are highly dependent on the supplied initial point. Convergence to local solutions often occurs, yielding incorrect phase and ...