scholarly journals Optimizing Interaction Parameters of Various Thermodynamics Models using MATLAB to Estimate Activity Coefficients of Azeotropic Mixtures

2019 ◽  
Vol 9 (1) ◽  
pp. 379-384
Keyword(s):  
Experimental Data ◽  
Activity Coefficients ◽  
Interaction Parameters ◽  
General Interest ◽  
Equilibrium Conditions ◽  
Unifac Model ◽  
Azeotropic Mixtures ◽  
Conventional Models ◽  
Irregular Behavior ◽  
Vapor Phase Equilibrium

The calculation of the liquid-vapor phase equilibrium conditions in multicomponent mixtures is a subject of general interest for engineering. So in this article, interaction parameters of various thermodynamics models are optimized using MATLAB and the vapor-liquid equilibrium conditions are estimated through the application of the modified Raoult’s equation. Activity coefficients of azeotropic mixtures are also estimated. The application of conventional models is restricted for those systems that exhibit irregular behavior, that is, they form azeotropic. In these cases, the validity of these models is limited since the experimental data is not satisfactorily explained. The UNIFAC model completely explains the experimental data of non-ideal systems quite well.

Solid-Fluid Phase Equilibria Measurement for Mixtures of Methane, Carbon-Dioxide and N-Hexadecane

2021 ◽  
Author(s):  
Oluwakemi Victoria Eniolorunda ◽  
Antonin Chapoy ◽  
Rod Burgass
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Equation Of State ◽  
Phase Equilibria ◽  
Activity Coefficients ◽  
Fluid Phase ◽  
Ternary Mixtures ◽  
Binary Interaction ◽  
Thermodynamic Models ◽  
Methane Carbon

Abstract In this study, new experimental data using a reliable approach are reported for solid-fluid phase equilibrium of ternary mixtures of Methane-Carbon-dioxide- n-Hexadecane for 30-73 mol% CO2 and pressures up to 24 MPa. The effect of varying CO2 composition on the overall phase transition of the systems were investigated. Three thermodynamic models were used to predict the liquid phase fugacity, this includes the Peng Robison equation of state (PR-EoS), Soave Redlich-Kwong equation of state (SRK-EoS) and the Cubic plus Association (CPA) equation of state with the classical mixing rule and a group contribution approach for calculating binary interaction parameters in all cases. To describe the wax (solid) phase, three activity coefficient models based on the solid solution theory were investigated: the predictive universal quasichemical activity coefficients (UNIQUAC), Universal quasi-chemical Functional Group activity coefficients (UNIFAC) and the predictive Wilson approach. The solid-fluid equilibria experimental data gathered in this experimental work including those from saturated and under-saturated conditions were used to check the reliability of the various phase equilibria thermodynamic models.

New Group-Interaction Parameters of the UNIFAC Model:  Aromatic Methoxyl Binaries

2001 ◽  
Vol 40 (7) ◽  
pp. 1740-1747 ◽  
Author(s):  
Shou-Ming Hwang ◽  
Ming-Jer Lee ◽  
Ho-mu Lin
Keyword(s):  
Group Interaction ◽  
Interaction Parameters ◽  
Unifac Model

scholarly journals Application of COSMO-RS Method for the Prediction of Liquid-Liquid Equilibrium of Water/n-Dodecane/1-Butanol

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
S. Balasubramonian ◽  
Shekhar Kumar ◽  
D. Sivakumar ◽  
U. Kamachi Mudali
Keyword(s):  
Activity Coefficient ◽  
Mutual Solubility ◽  
Solubility Data ◽  
Interaction Parameters ◽  
Binary Interaction ◽  
Liquid Equilibrium ◽  
Model Interaction ◽  
Uniquac Model ◽  
Unifac Model ◽  
Lle Data

The liquid-liquid equilibrium (LLE) for the system water-dodecane-butanol was estimated using the UNIQUAC model. In the UNIQUAC model interaction parameters were estimated from the vapor-liquid equilibrium (VLE) and LLE data of their constituent binary pairs. The water-dodecane-butanol LLE was experimentally measured at 298.15 K. Phase stability constraints were taken into account while calculating the binary interaction parameters from the mutual solubility data. The COSMO-RS method was used to estimate the activity coefficient in the miscible binary pair. The ternary LLE composition was predicted using the experimental VLE data as well as using the COSMO-RS calculated activity coefficient data along with the experimental mutual solubility data. In the latter case the root mean square deviation (RMSD) for the distribution of butanol between aqueous and organic phase is 0.24%. The corresponding UNIFAC model prediction is 7.63%.

scholarly journals Treatment Interactions with Nonexperimental Data in Stata

2011 ◽  
Vol 11 (4) ◽  
pp. 545-555 ◽  
Author(s):  
Graham K. Brown ◽  
Thanos Mergoupis
Keyword(s):  
Experimental Data ◽  
Observational Data ◽  
Treatment Effect ◽  
Treatment Effects ◽  
Average Treatment Effect ◽  
Interaction Parameters ◽  
Average Treatment ◽  
Interaction Terms ◽  
Treatment Interaction ◽  
Predicted Values

Treatment effects may vary with the observed characteristics of the treated, often with important implications. In the context of experimental data, a growing literature deals with the problem of specifying treatment interaction terms that most effectively capture this variation. Some results of this literature are now implemented in Stata. With nonexperimental (observational) data, and in particular when selection into treatment depends on unmeasured factors, treatment effects can be estimated using Stata's treatreg command. Though not originally designed for this purpose, treatreg can be used to consistently estimate treatment interaction parameters. With interactions, however, adjustments are required to generate predicted values and estimate the average treatment effect. In this article, we introduce commands that perform this adjustment for multiplicative interactions, and we show the required adjustment for more complicated interactions.

A FRACTAL ANALYSIS OF SUBCOOLED NUCLEATE POOL BOILING

Fractals ◽  
2008 ◽  
Vol 16 (01) ◽  
pp. 1-9 ◽  
Author(s):  
BOQI XIAO ◽  
ZONGCHI WANG ◽  
BOMING YU
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Fractal Model ◽  
Nucleate Pool Boiling ◽  
Empirical Constant ◽  
Pool Boiling Heat Transfer ◽  
Model Predictions ◽  
Conventional Models

A fractal model for the subcooled nucleate pool boiling heat transfer is proposed in this paper. The analytical expressions for the subcooled nucleate pool boiling heat transfer are derived based on the fractal distribution of nucleation sites on boiling surfaces. The proposed fractal model for the subcooled nucleate pool boiling heat transfer is found to be a function of wall superheat, liquid subcooling, fractal dimension, the minimum and maximum active cavity size, the contact angle and physical properties of fluid. No additional/new empirical constant is introduced, and the proposed model contains less empirical constants than the conventional models. The model predictions are compared with the existing experimental data, and fair agreement between the model predictions and experimental data is found for different liquid subcoolings.

scholarly journals Flash point of organic binary mixtures containing alcohols: experiment and prediction

2013 ◽  
Vol 11 (3) ◽  
pp. 388-393 ◽  
Author(s):  
Mariana Hristova ◽  
Dimitar Damgaliev
Keyword(s):  
Experimental Data ◽  
Activity Coefficient ◽  
Binary Mixtures ◽  
Activity Coefficients ◽  
Thermodynamic Model ◽  
Flash Point ◽  
Wilson Equation ◽  
Nrtl Equation

AbstractThe flash points of three organic binary mixtures containing alcohols were measured in the present work. The experimental data was obtained using the Pensky-Martens closed cup tester. The experimental data were compared with the values calculated by the Liaw model. Activity coefficients were calculated by the Wilson equation and NRTL equation. The accuracy of predicted flash point values is dependent on the thermodynamic model used for activity coefficient.

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