How to Compute Binary Vapor-Liquid Equilibrium Compositions from Experimental P-x or t-x Data

Tao, Luh C.

doi:10.1021/ie50616a032

Cited by 33 publications

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“…Fortunately, there is also an enormous simplification in the resulting equations as compared with the corresponding liquid-phase calculations. Now, Equation (7) This can be solved for XI to give Inspection of Equation (9) shows why Equation (2) was invalid, in general, for multicomponent mixtures. By assuming an ideal gas phase and by ignoring the liquid phase volume, Equation (2) becomes…”

Section: Dew Point Pressure Methodsmentioning

confidence: 99%

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

Davison¹,

James²,

Tromblee³

1970

AIChE Journal

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Numerical integration of total vapor pressure-liquid composition curves with the Gibbs-Duhem equation is an established tool for calculating vapor-liquid equilibria of binary systems (1 to 9). The procedure is usually employed with isothermal data, since isobaric data may require accurate values of the heat of mixing. In contrast, it has only rarely been used for multicomponent systems. This is largely explained by the increasing complexity of the calculational procedures and the greater quantity of data required as the number of components is increased beyond 2.Mixon et al. (10) have given a general procedure for isothermal multicomponent total pressure-liquid composition data. It is essentially a generalization of the method of Tao (9) in which nj refers to constant mole numbers for all components except component 1, and + is a correction for gas phase nonideality. The derivatives are taken such that all mole fractions except XI remain in a fixed ratio as XI is varied. It can be shown that this is exact for an ideal liquid phase. Unfortunately, it is not correct for nonideal liquid phases in multicomponent systems, as will be explained later. DEW POINT PRESSURE METHODAll the above methods, both binary and multicomponent, employ bubble point pressures and composition with the Gibbs-Duhem equation for the calculation of the vapor-phase composition. There is no reason, however, why dew point pressures and vapor-phase compositions cannot be used. While the equipment for dew point measurements is more complex, such apparatus have been constructed, and variations could easily be designed.Generally, the sample would be vaporized and the isothermal pressure-volume relations recorded until condensa-R. James is at Massachusetts Institute of Technology. Cambridge, Massachusetts.tion occurred, as noted by a break in the pressure-volume curve; if the pressure rise is rapid as compared with heat transfer, the process will be nearly adiabatic. Then AT/AP = u/CP Since the apparent heat capacity will include the latent heat, it will show a large change at the dew point. An obvious bonus from this procedure would be the byproduct pressure-volume data from which fugacity coefficients could be calculated. The unavailability of the latter is frequently the weakness in the total pressure method. Fortunately, there is also an enormous simplification in the resulting equations as compared with the corresponding liquid-phase calculations. where nj represents %. n3, ---n~. Now

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Section: Dew Point Pressure Methodsmentioning

confidence: 99%

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

Davison¹,

James²,

Tromblee³

1970

AIChE Journal

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“…XVIII KÖIDE KEEMIA * GEOLOOGIA, 1969, Nr. 4 ИЗВЕСТИЯ АКАДЕМИИ НАУК ЭСТОНСКОЙ ССР. ТОМ XVIII ХИМИЯ * ГЕОЛОГИЯ.…”

Section: экспериментальная частьunclassified

“…Конечные результаты вычислений, составы равновесных фаз, корригированная упругость паров p k , коэффициенты активности для фенола yi и углеводорода у2, а также относительная летучесть а приведены в табл. 4…”

Section: экспериментальная частьunclassified

Равновесие Пар-Жидкость В Бинарных Системах, Содержащих Одноатомные Фенолы И Углеводороды I. Изотермическое Равновесие Пар–жидкость В Смесях Фенол–углеводороды

Aarna¹,

Kaps²,

Malanovski³

1969

Eesti NSV Teaduste Akadeemia Toimetised. Keemia. Geoloogia

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“…Tao's procedure involves calculation of the activity coefficient essentially by integration of an equation resembling the coexistence equation. His procedure, though indirect, retains the rigor usually associated with the direct method [6]. The method of Tao appears specific to binary systems and does not seem to be easily generalized.…”

Section: Introductionmentioning

confidence: 99%

Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and
Gao
¹
,
Zhang
²
,
Lücking
³

et al. 2012
Journal of Thermodynamics

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Vapor-liquid equilibrium (VLE) data for the strongly associated ternary system methanol + water + ethanoic acid and the three constituent binary systems have been determined by the total pressure-temperature-liquid-phase composition-molar excess enthalpy of mixing of the liquid phase (p, T, x, HmE) for the binary systems using a novel pump ebulliometer at 101.325 kPa. The vapor-phase compositions of these binary systems had been calculated from Tpx and HmE based on the Q function of molar excess Gibbs energy through an indirect method. Moreover, the experimental T, x data are used to estimate nonrandom two-liquid (NRTL), Wilson, Margules, and van Laar model parameters, and these parameters in turn are used to calculate vapor-phase compositions. The activity coefficients of the solution were correlated with NRTL, Wilson, Margules, and van Laar models through fitting by least-squares method. The VLE data of the ternary system were well predicted from these binary interaction parameters of NRTL, Wilson, Margules, and van Laar model parameters without any additional adjustment to build the thermodynamic model of VLE for the ternary system and obtain the vapor-phase compositions and the calculated bubble points.

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How to Compute Binary Vapor-Liquid Equilibrium Compositions from Experimental P-x or t-x Data

Cited by 33 publications

References 0 publications

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

Равновесие Пар-Жидкость В Бинарных Системах, Содержащих Одноатомные Фенолы И Углеводороды I. Изотермическое Равновесие Пар–жидкость В Смесях Фенол–углеводороды

Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and
Gao
¹
,
Zhang
²
,
Lücking
³

et al. 2012
Journal of Thermodynamics

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How to Compute Binary Vapor-Liquid Equilibrium Compositions from Experimental P-x or t-x Data

Cited by 33 publications

References 0 publications

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

A method for multicomponent equilibrium calculations by using dew point pressure‐vapor composition data

Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and Gao1, Zhang2, Lücking3 et al. 2012Journal of Thermodynamics

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Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and
Gao
¹
,
Zhang
²
,
Lücking
³

et al. 2012
Journal of Thermodynamics