Mixing rules for the back equation of state

1987 ◽  
Vol 52 (1) ◽  
pp. 29-44 ◽  
Author(s):  
Tomáš Boublík ◽  
Benjamin C.-Y. Lu
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Equation Of State ◽  
Van Der Waals ◽  
Energy Parameter ◽  
Excess Properties ◽  
Mixing Rules ◽  
Good Prediction ◽  
Mixing Rule ◽  
Simple Molecules

Van der Waals type of mixing rule for the energy parameter us together with the mixing rules introduced previously for parameters αs and Vs0 of the BACK equation were employed in evaluating excess properties of mixing, Henry's law constant and high pressure vapour-liquid equilibria. A comparison with the experimental data reveals that the BACK equation together with the suggested mixing rules could provide good prediction of equilibrium properties of mixtures of relatively simple molecules.

scholarly journals Drawing PT-phase envelopes and calculating critical points for multicomponent systems using flash calculations

2020 ◽  
Vol 15 (1) ◽  
pp. 46-54
Author(s):  
L. A. Toro
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Critical Points ◽  
Isopropyl Alcohol ◽  
Equations Of State ◽  
Mixing Rules ◽  
Mixing Rule ◽  
Multicomponent Systems ◽  
Activity Coefficient Model ◽  
Robinson Equation

Objectives. This study aims to draw PT-phase envelopes and calculate the critical points for multicomponent systems using flash calculations.Methods. Flash calculations with an equation of state and a mixing rule were used to construct phase envelopes for multicomponent systems. In general, the methodology uses the Soave–RedlichKwong equation of state and Van der Waals mixing rules; and the Peng–Robinson equation of state with Wong–Sandler mixing rules and the non-random two-liquid activity coefficient model.Results. The method was applied to the following mixtures: ethane (1)–butane (2) (four different compositions); ethane (1)–propane (2) (four different compositions); butane (1)–carbon dioxide (2) (three different compositions); C2C3C4C5C6 (one composition); isobutane–methanol–methyl tertbutyl ether–1-butene (one composition); and propylene–water–isopropyl alcohol–diisopropyl ether (one composition).Conclusions. Our results agreed to a large extent with the experimental data available in the literature. For mixtures that contained CO2 , the best results were obtained using the PengRobinson equation of state and the Wong–Sandler mixing rules. Our methodology, based on flash calculations, equations of state, and mixing rules, may be viewed as a shortcut procedure for drawing phase envelopes and estimating critical points of multicomponent systems.

Comparative Study of Linear Co-Volume Based Mixing Rules for Equation of State/ Excess Gibbs Energy (EOS/GE) Models for CO2 – MEA and CO2 – MDEA Systems

2014 ◽  
Vol 625 ◽  
pp. 541-544 ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Equation Of State ◽  
Gibbs Energy ◽  
Comparative Study ◽  
Excess Gibbs Energy ◽  
High Pressures ◽  
Mixing Rules ◽  
Good Prediction ◽  
Mixing Rule ◽  
Polar Mixtures ◽  
Reference Pressure

With the advent of Equation of State/ Excess Gibbs Energy (EOS/GE) models, the linear co-volume based mixing rules have gained vast importance for predicting multi-component VLE for polar mixtures. Owing to their inherent ease of calculation and good prediction abilities, these mixing rules have been applied in extension, to a variety of systems especially for CO2-H2O-alkanolamine systems. However, no comparative study is available to select appropriate mixing rule for prediction of thermodynamic properties. In this study, pressure prediction of various linear co-volume mixing rules has been compared for CO2– MEA and CO2– MDEA systems, while effects of activity coefficients and process parameters have been kept constant. The infinite pressure mixing rules have heavily under – predicted and approximate zero reference pressure mixing rules have over – predicted, but latter are valid for low and medium pressure ranges. The linear combination of Vidal and Michelsen (LCVM) mixing rule have good predictions at high pressures.

scholarly journals Application of PC-SAFT and cubic equations of state for the correlation of solubility of some pharmaceutical and statin drugs in SC-CO2

2013 ◽  
Vol 19 (3) ◽  
pp. 449-460 ◽  
Author(s):  
El Abdallah ◽  
C. Si-Moussa ◽  
S. Hanini ◽  
M. Laidi
Keyword(s):  
Experimental Data ◽  
Equations Of State ◽  
Van Der Waals ◽  
Energy Parameter ◽  
Pure Component ◽  
Binary Interaction ◽  
Statistical Associating Fluid Theory ◽  
Binary Interaction Parameters ◽  
Fluid Theory ◽  
Statin Drugs

In this work, the solubilities of some anti-inflammatory (nabumetone, phenylbutazone and salicylamide) and statin drugs (fluvastatin, atorvastatin, lovastatin, simvastatin and rosuvastatin) were correlated using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) with one-parameter mixing rule and commonly used cubic equations of state Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) combining with van-der Waals-1 parameter (VDW1) and van-der Waals-2 parameters (VDW2) mixing rules. The experimental data for studied compounds were taken from literature at temperature and pressure in ranges (308-348 K) and (100-360 bar) respectively. The critical properties required for the correlation with PR and SRK were estimated using Gani and Noonalol contribution group methods whereas, PC-SAFT pure-component parameters; segment number (m), segment diameter (?) and energy parameter (?/k) have been estimated by tihic?s group contribution method for nabumetone. For phenylbutazone and salicylamide those parameters were determined using a linear correlation. For statin drugs, PC-SAFT parameters were fitted to solubility data, and binary interaction parameters (kij and lij) have been obtained by fitting the experimental data. The result was found to be in good agreement with the experimental data and showed that PC-SAFT approach can be used to model solid-SCF equilibrium with better correlation accuracy than cubic equations of state.

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