Ternary Vapor–liquid Equilibrium Data Research Articles

Vapor–liquid equilibria for the ternary system of carbon dioxide + ethanol + ethyl acetate at elevated pressures

Vapor–liquid equilibrium (VLE) data for the ternary system of carbon dioxide, ethanol and ethyl acetate were measured in this study at 303.2, 308.2, and 313.2 K, and at pressures from 4 to 7 MPa. A static type phase equilibrium apparatus with visual sapphire windows was used in the experimental measurements. New VLE data for CO 2 in the mixed solvent were presented. These ternary VLE data at elevated pressures were also correlated using either the modified Soave–Redlich–Kwong or Peng–Robinson equation of state, with either the van der Waals one-fluid or Huron–Vidal mixing model. Satisfactory correlation results are reported with temperature-independent binary parameters. It is observed that at 313.2 K and 7 MPa, ethanol can be separated from ethyl acetate into the vapor phase at all concentrations in the presence of high pressure CO 2.

Isothermal and Isobaric Vapor−Liquid Equilibria of the Ternary System of 2,2-Dimethoxypropane + Acetone + Methanol

The isothermal (T = 323.15 K) and the isobaric (P = 66.66 kPa and 79.99 kPa) vapor−liquid equilibria (VLE) for the ternary system of 2,2-dimethoxypropane + acetone + methanol were measured with an inclined ebulliometer. The measured results for the ternary system are compared with the calculated ones from the UNIQUAC equation using only temperature-dependent binary parameters obtained from the binary literature values and resulted in satisfactory results. The ternary VLE data are useful in the design of efficient separation process of 2,2-dimethoxypropane, acetone, and methanol.

Vapor−Liquid Equilibria for the Ternary Systems of Methyl tert-Butyl Ether + Methanol + Methylcyclohexane and Methyl tert-Butyl Ether + Methanol + n-Heptane and Constituent Binary Systems at 313.15 K

Isothermal vapor−liquid equilibrium (VLE) data are measured for the ternary systems of methyl tert-butyl ether (MTBE) + methanol + methylcyclohexane (MCH) and MTBE + methanol + n-heptane and constituent four binary systems, MTBE + MCH, MTBE + n-heptane, methanol + MCH, and methanol + n-heptane, at 313.15 K. The experimental binary VLE data were correlated with common gE model equations. The correlated Wilson and NRTL parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson and NRTL parameters and the predicted data using modified UNIFAC (Dortmund) model were compared with experimental ternary data.

Isobaric vapor-liquid equilibrium for methyldichlorosilane-methyltrichlorosilane-dimethyldichlorosilane system

This paper describes measurement of vapor-liquid equilibrium (VLE) data of methyldichlorosilane-methyltrichlorosilane-dimethyldichlorosilane system and that of the three binary systems at 101.325 kPa with a new pump-ebulliometer. The equilibrium composition of the vapor phase was calculated from pTx by indirect method. The model parameters of the liquid activity coefficient of the Wilson, NRTL, Margules and van Laar equations was corrected by the least square method. The ternary system VLE data were predicted by the Wilson equation, with the calculated boiling points showing good agreement with the experimental data.

Isobaric Vapor−Liquid Equilibria for Water + Acetic Acid + (n-Pentyl Acetate or Isopropyl Acetate)

Isobaric vapor−liquid equilibria (VLE) data for water + acetic acid, acetic acid + isopropyl acetate, acetic acid + n-pentyl acetate, water + acetic acid + isopropyl acetate, and water + acetic acid + n-pentyl acetate systems have been measured at 101.33 kPa using a recirculating still. The nonideality of the vapor phase caused by the association of the acetic acid has been corrected by the Hayden−O'Connell method. The three experimental binary data have been correlated by the NRTL and UNIQUAC models. The obtained NRTL model parameters from binary data have been used to predict ternary VLE data. The ternary predicted values obtained in this way agree well with the experimental values.

Simulation of Salt-Containing Extractive Distillation for the System of Ethanol/Water/Ethanediol/KAc. 1. Calculation of the Vapor−Liquid Equilibrium for the Salt-Containing System

Quaternary vapor−liquid equilibrium (VLE) data were measured for the system of ethanol/water/ethanediol/potassium acetate (KAc). Binary salt-containing VLE data were correlated with the salt-containing local composition model (SCLCM). For a multicomponent system, ternary and quaternary VLE data predicted by SCLCM are in agreement with the literature data and data in this work. The influence of KAc, ethanediol, and the mixture of KAc and ethanediol on the system was investigated by the SCLCM method, and the results showed that the additives have different influences on the volatility of ethanol and water. The calculation method of the salt-containing VLE is simple and effective for the system.

Vapor–liquid equilibria for the ternary systems of methyl tert-butyl ether + methanol + benzene and methyl tert-butyl ether + methanol + toluene and constituent binary systems at 313.15 K

Isothermal vapor–liquid equilibria (VLE) data are measured for the ternary systems of methyl tert-butyl ether (MTBE)+methanol+benzene and MTBE+methanol+toluene and constituent five binary systems, MTBE+methanol, MTBE+benzene, MTBE+toluene, methanol+benzene, and methanol+toluene, at 313.15 K. The experimental binary VLE data were correlated with common g E model equations. And the correlated Wilson and NRTL parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson and NRTL parameters were compared with experimental ternary data.

Isothermal vapor–liquid equilibria and excess molar volumes for the ternary mixtures containing 2-methyl pyrazine

Isothermal vapor–liquid equilibrium (VLE) data at 353.15 K and excess molar volumes ( V E) at 298.15 K are reported for the binary systems of ethyl acetate (EA)+cyclohexane and EA+ n-hexane and also for the ternary systems of EA+cyclohexane+2-methyl pyrazine (2MP) and EA+ n-hexane+2MP. The experimental binary VLE data were correlated with common g E model equations. The correlated Wilson parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson parameters were compared with experimental ternary data. The experimental excess molar volumes were correlated with the Redlich–Kister equation for the binary mixtures, and Cibulka’s equation for the ternary mixtures.

Predictions of the solubility of acid gases in monoethanolamine (MEA) and methyldiethanolamine (MDEA) solutions using the electrolyte-UNIQUAC model

A thermodynamic model was developed for representing vapor–liquid equilibria (VLE) of the CO 2–H 2S–MEA–MDEA–water system. The model accounts for chemical equilibria in the liquid phase and physical equilibria between the liquid and vapor phases. Activity coefficients are represented by the electrolyte-UNIQUAC equation. The present extension uses an ion-pair interaction approach and satisfies both the principles of like-ion repulsion and local electroneutrality. Contributions from long-range ion–ion interactions are represented by a Debye–Hückel formula suitable for mixed solvents, water and alkanolamines. Adjustable parameters of the electrolyte-UNIQUAC equation, representing short-range binary interactions, were determined by data regression using binary, ternary, and quaternary system VLE data. Predicted H 2S and CO 2 vapor pressures are in good agreement with the reported experimental data for aqueous solutions of a single acid gas as well as mixtures of H 2S and CO 2 in MEA and MDEA and their mixtures in the temperature range 25–120°C.

Prediction of Phase Equilibria for Binary and Ternary Mixtures Involvingtert-Butyl Methyl Ether andtert-Amyl Methyl Ether

Vapor−liquid equilibrium (VLE) and excess enthalpy (HE) data of binary and ternary mixtures involving 1,1-dimethylethyl methyl ether (tert-butyl methyl ether or MTBE) or 1,1-dimethylpropyl methyl ether (tert-amyl methyl ether or TAME) and alkanes, olefins, benzene, and alcohols have been studied using the UNIQUAC model, the original UNIFAC group contribution model, and the modified UNIFAC models of Lyngby and Dortmund. Values for the binary parameters required in the UNIQUAC model are obtained from binary VLE or HE data. Binary VLE data are predicted using the UNIQUAC equation with parameters obtained from HE data and the UNIFAC and modified UNIFAC models. Ternary VLE data are predicted using the UNIQUAC equation with parameters obtained from binary HE or VLE data and the UNIFAC and modified UNIFAC models. Accurate ternary data are obtained using the UNIQUAC equation with parameters determined from binary VLE data. The modified UNIFAC (Dortmund) model is shown to provide good predictions of binary and ter...

A study on ternary vapor-liquid equilibria for the system heptane/methylcyclohexane/toluene at 101.325kPa

The isobaric separation of multicomponent mixtures by distillation require reliable vapor-liquid equilibrium data. Since the experimental determination of multicomponent vapor-liquid equilibrium data is laborious and time consuming there is a need to use a predictive method for the liquid phase activity coefficients. The estimated vapor-phase compositions are dependent on the predictive thermodynamic method used. The ternary vapor-liquid equilibrium data for the system, heptane/ methylcyclohexane/ toluene at 101.325 kPa have been chosen to compare the abilities of the three-suffix Margules and the UNIQUAC Equations in the prediction of isobaric ternary vapor-liquid equilibria with parameters estimated from the corresponding binary vapor-liquid equilibria compositions taken from the literature. The predictions with the three-suffix Margules equations was found to be little superior with overall root mean square deviations of ±0.0047 whereas the UNIQUAC equations could predict the ternary vapor compositions with overall root mean square deviations of ± 0.0061.

Measurements of the heats of dilution and description of the system H 2O/H 2SO 4/HCl with a solvation model

Heat of dilution measurements have been performed on the system H 2O/H 2SO 4/HCl in the concentration range of 0.3 mol% to 20 mol% electrolyte and in the temperature range of 20°C to 60°C. The constituent binary systems H 2O/H 2SO 4 and H 2O/HCl could be described using the solvation model introduced by Engels [H. Engels, Anwendung des modells der lokalen zusammensetzung auf elektroytlösungen, Dissertation, RWTH Aachen, 1985]. The vapor–liquid-equilibria (VLE) and the thermal properties are described simultaneously by one set of parameters. Applying the solvation model to the ternary system H 2O/H 2SO 4/HCl, the measured heats of dilution as well as VLE-data taken from the literature could be predicted. The heat of dilution data are presented with a mean relative deviation of 3.5%. The boiling temperatures of the three sources of ternary VLE data considered in this paper are predicted with a mean absolute deviation of less than 1.2 K. The corresponding mean absolute deviations of the vapor mole fractions of HCl are within 0.06.

Vapour-liquid equilibria for some binary and ternary polymer solutions

Vapour-liquid equilibrium (VLE) data for seven binary polymer + solvent systems and for one ternary polymer + mixed solvent system have been obtained using the gravimetric-sorption method at 50°C. The binary polymer + solvent mixtures studied include polystyrene (PS), poly(methyl methacrylate) (PMMA) and the random copolymer poly(styrene-co-50% methyl methacrylate) in acetone, methyl acetate and chloroform. Solvent absorption by the copolymer was inbetween those by PS and PMMA for chloroform, but it was less than those by either homopolymer for acetone and methyl acetate. A modification to the classic gravimetric-sorption technique was established for acquiring sorption data for polymer + mixed solvent systems. VLE data were obtained for polystyrene + chloroform + carbon tetrachloride. A perturbed hard-sphere chain (PHSC) equation of state was used to correlate binary and ternary VLE data.

Vapor-liquid equilibria of the ternary system methanol + acetone + methyl vinyl ketone at atmospheric pressure

Isobaric vapor-liquid equilibrium (VLE) data at atmospheric pressure for the ternary system methanol + acetone + methyl vinyl ketone have been experimentally obtained. The measurements were conducted in a two-phase recirculation still. The experimental VLE data were correlated according to the Margules, Wilson, NRTL and UNIQUAC equations. The ternary VLE data were predicted from their constituent binaries. A comparison of model performances was made using the criterion of average absolute deviations in boiling point and in vapor-phase composition.

An expression for GE for use in the reduction of ternary vapor-liquid equilibrium data

Abstract Campbell, S.W. 1992. An expression for G E for use in the reduction of ternary vapor-liquid equilibrium data. Fluid Phase Equilibria, 74: 35-46. A new empirical correlating expression for the excess Gibbs free energy is proposed for use in reduction of ternary vapor-liquid equilibrium data. The equation results from an attempt to combine the desirable aspects of local composition equations and those based on Wohl's expansion. The method is applied to two ternary systems, each of which is comprised of two alcohols and a hydrocarbon. The new equation compares favorably to previously attempted methods in that it provides a slightly better representation of the ternary data while utilizing fewer adjustable parameters.

Prediction of fluid phase equilibrium of ternary mixtures in the critical region and the modified Leung–Griffiths theory

The modified Leung–Griffiths theory of vapor–liquid equilibrium (VLE) is generalized to the case of three components. The principle of ‘‘corresponding states’’ is reconsidered along with certain functions of ‘‘field variables’’ within the model. The mathematical form of the coexistence boundary in terms of the field variables remains practically unchanged and conforms to modern scaling theory. The new model essentially predicts ternary fluid mixture phase boundaries in the critical region from previous vapor–liquid equilibrium data correlations of the three binary fluid mixture limits. Predicted saturation isotherms of the ethane+n-butane+n-pentane and ethane+n-butane+n-heptane mixtures are compared with experimental ternary VLE data in the literature.

Applicability of the unifac method for prediction of binary and ternary vapour-liquid equilibrium data in systems formed by hydrocarbons and alcohols

The problem of the prediction and correlation of vapour-liquid equilibria in binary and ternary systems has been discussed and the limitation in the applicability of the UNIFAC method for this purpose has been pointed out. The total pressure data for six ternary systems (cyclohexane-2-propanol-benzene, cyclohexane-ethanol-benzene, n-heptane-1-propanol-benzene, n-hexane-ethanol- benzene, cyclohexane-methanol-benzene, cyclohexane-ethanol-toluene) and eighteen corresponding binary mixtures (benzene-2-propanol, benzene-cyclohexane, cyclohexane-2-propanol, cyclohexane-ethanol, cyclohexane-benzene, ethanol-benzene, ethanol-benzene, n-hexane-benzene, n-hexane-ethanol, benzene-1-propanol, benzene- n-hexane, n-heptane-1-propanol, cyclohexane-methanol, benzene-cyclohexane, benzene-methanol, cyclohexane-ethanol, benzene-cyclohexane, benzene-ethanol) have been selected and correlated by means of the Redlich-Kister equation and compared with the results predicted by the UNIFAC method. The correlation and the prediction results have been fully discussed from the point of view of intermolecular interactions and some recommendations have been made on the use of the methods investigated for such calculations.

Prediction of thermodynamic properties of ternary hydrocarbon mixtures containing olefins. I. 1-Alkenes + benzene + n-alkanes

Excess enthalpies and excess Gibbs energies (vapor-liquid equilibria) of ternary systems formed by 1-alkenes + benzene + n-alkanes are predicted from a generalized quasi-lattice group contribution theory. All the parameters were obtained by application of the same theory to the experimental values of the corresponding classes of binary systems after a thorough bibliographical search. The results compare satisfactorily with the only available experimental ternary vapor-liquid equilibrium data set found in the literature for this type of systems.

Ternary liquid—liquid equilibria for acetonitrile—ethanol—cyclohexane and acetonitrile—2-propanol—cyclohexane

Liquid—liquid equilibrium data were obtained for two ternary systems: acetonitrile— ethanol—cyclohexane at 40°C, and acetonitrile—2-propanol—cyclohexane at 50°C. Binary vapor—Liquid equilibrium data were measured for acetonitrile—2-propanol at 50°C. The binary parameters of the Zeta and effective Zeta equations were evaluated from equilibrium data for binary pairs. The parameters obtained were used to predict the ternary liquid—liquid equilibrium data for six systems involving the present systems and the ternary vapor—liquid equilibrium data for one completely miscible system and two partially miscible systems without adding any ternary parameter. A heterogeneous area calculated by the Zeta equation is in general too large and does not decrease appreciably with increasing values of the third parameter ζ of the Zeta equation. However, the effective Zeta equation works much better than the original Zeta equation in data reduction.

The prediction of isobaric phase equilibria for non-ideal multicomponent mixtures from heat of mixing data

A method for predicting isobaric binary and ternary vapor—liquid equilibrium data using only isothermal binary heat of mixing data and pure component vapor pressure data is presented. Three binary and two ternary hydrocarbon liquid mixtures were studied. The method consists of evaluating the parameters of the NRTL equation from isothermal heat of mixing data for the constituent binary pairs. These parameters are then used in the multicomponent NRTL equation to compute isobaric vapor—liquid equilibrium data for the ternary mixture. No ternary or higher order interaction terms are needed in the ternary calculations because of the nature of the NRTL equation. NRTL parameters derived from heat of mixing data at one temperature can be used to predict vapor—liquid equilibrium data at other temperatures up to the boiling temperature of the liquid mixture. For the systems studied this method predicted the composition of the vapor phase with a standard deviation ranging from 1–8% for the binary systems and from 4–12% for the ternary systems.