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Vapor-Liquid Phase Equilibria Of Nonideal Fluids With A Ge-Eos Model, Socrates Ioannidis

Dissertations

This study dealt with the prediction and correlation of vapor-liquid equilibria behavior of nonideal fluids. The thermodynamic formalism of the G^E-EoS models, which combines the two traditional methods γ-Φ and Φ-Φ used so far for low and high pressure phase equilibria correlations respectively, has been combined with the 1FG^E model, based on one-fluid theory, to produce a more consistent approach to the phase equilibrium problem.

In the first part of our study we examine the predictive abilities of our model for vapor-liquid equilibria of highly nonideal fluids. The results establish the fact that the Huron-Vidal mixing rule …

Thermodynamic And Leaching Studies Of Various Systems, Satya D. Rami

Theses

The group contribution approach is a reliable and fast method for the prediction of liquid phase activity coefficients in none lectrolyte, nonpolymeric mixtures at low to moderate pressures and temperatures between 300 and 425 K. It has become widely used in practical chemical engineering applications in cases where little or no relevant experimental information is available.

The two group contribution methods examined in the course of this work, are the Knox and & UNIFAC models. Group interaction parameters are evaluated for each of these models and results compared. Although the results for both models are similar when sufficient data are …

Prediction Of Vapor And Liquid Equilibrium Properties For 25 Organic Priority Pollutants In Aqueous Solution, Pinchieh Pai

Theses

Activity coefficients and Henry's law constants for 25 organic priority pollutants were estimated using UNIFAC thermodynamic calculations. For 6 of these compounds, the results were compared with measured values reported in the literature. This indicated errors in the UNIFAC predictions varying from 24.0% to 95.0%. Best results with UNIFAC were obtained using liquid-liquid equilibria, rather than vapor-liquid equilibria.

Octanol/water partition coefficients were also estimated for the same 25 organic priority pollutants using the fragment constant method. Results differed from values reported in the literature by 5% to 170%.

Estimated activity coefficients were also used to predict stripping rates of organic …

Vapor Pressures Of Some Coal Oil Fractions, David G. Gaydos

Theses

New data on coal tar oils and data from the literature on pure compounds and oils derived from coal were used for testing the predictions by the correlation of Maxwell—Bonnell. Based on the observation that the discrepancies between the predicted values and the data are systematic, recommendations were deduced on needed modifications to the correlation. A proposal for modification to the Maxwell and Bonnell correlation to improve prediction of vapor pressures of highly aromatic fuel fractions with characterization factors of8 UOPK 10.5 was made.

Experimental data were taken on vapor pressures of fractions of coke oven coal tar oils and …

Prediction Of Vapor-Liquid Equilibrium From Ternary Liquid-Liquid Equilibrium Data, David Kim Yee

Theses

Reasonable estimates of ternary vapor-liquid equilibrium can be obtained by using the corresponding liquid-liquid equilibrium (LLE) data with the NRTL, LEMF and UNIQUAC models. The overall average absolute deviation in vapor phase concentration for seven such systems is 0.028.: Use of the UNIFAC method gives erratic predictions suggesting caution when applied to such systems. Combination, however, of the LLE data and the UNIFAC method gives the best results with a deviation of 0.020 Prediction of binary VLE behavior from LLE data yields also reasonably good results.

Calculations Of Isobaric Phase Enthalpy Differences For Binary Systems From Vapor-Liquid Equilibrium Data, Steven Merrill Harvey

Theses

Equations relating isobaric vapor-liquid equilibrium data to heats of vaporization are useful in testing the thermodynamic consistency of experimental VLE data and in the design of distillation equipment. Several researchers have proposed such equations based on the Gibbs-Duhem equation. At low pressures, simplified versions of these equations were successfully used to test the consistency of published VLE and enthalpy data. At high pressures, equilibrium phase enthalpy differences were calculated from rigorous equations using a modified form of the Redlich-Kwong equation to calculate fugacity coefficients. As expected, the relative error of using the simplified equations was found to increase with increasing …

Vapor-Liquid Equilibrium At Low Pressures : Correlation Of Binary And Prediction Of Multicomponent Data, Norman I. Silverman

Theses

The Wilson equation is chosen as typical of the new correlations for activity coefficients gaining wide distribution for use in the correlation and prediction of vapor-liquid equilibria today. Vapor liquid equilibrium data for 247 binary systems have been regressed against each of ten (10) objective functions and values of the Wilson energy parameters obtained. For the typical binary system, a wide variation of the Wilson energy parameters are observed when different objective functions are used with the given set of binary data. These are each examined with respect to their capability to correlate multicomponent vapor-liquid equilibrium data for seventy-three (73) …

Prediction And Correlation Of The Salt-Effect In Vapor-Liquid Equilibrium, Enrique M. Bekerman

Theses

The feasibility of developing a method of correlation and prediction, for mixtures of two solvents containing a dissolved salt has been studied. The procedure consisted of arriving at the interaction parameters for the three binary systems (solvent 1-solvent 2, solvent 1-salt, solvent 2-salt) and using these to calculate the ternary results. Attempts to generate interaction parameters for the solvent-salt binaries by means of the Wilson equation were unsuccessful, whereas, use of the NRTL equation resulted in a very good fit of the binary data.

In correlating the ternary results, it became necessary to redefine the liquid phase mole fractions and …

A Preliminary Study Of The Thermodynamic Limitations Of The Nrtl/Lemf Equations, Robert Petrie

Theses

Analytical evaluations of the second and third derivatives of the molar Gibbs energy of mixing for the NRTL/LEMF equations indicate distinct zones of miscible and inmiscible prediction.

These calculations for a number of different α's have produced approximate miscibility limits for both NRTL/LEMF energy parameters and infinite dilution activity coefficients of a given system.

Evaluation Of Herington General Integral Test For Vapor-Liquid Equilibrium Data, Raja Gopal Nori

Theses

A new set of general integral tests for the thermodynamic consistency of isothermal and isobaric equilibrium data of binary systems was proposed by E.F.G. Herington.

The systems Benzene-Cyclohexane and Benzene-n-Propanol were examined using Herington integral test-. The data used included sets of data known to be in error. One set was, in effect, at true vapor-liquid equilibrium (the data of literature) but the other data was obtained when the system was inadequately insulated and heated.

Heringtan test showed significantly different estimates for heats of mixing for the cases involved. The best data showed heats of mixing near the theoratical values. …