Phase Equilibria and Excess Properties of Short-Alkane Mixtures Estimated Using the SAFT-VR Equation of State

2014 ◽  
Vol 59 (10) ◽  
pp. 3242-3249 ◽  
Author(s):  
Manuel M. Piñeiro ◽  
Felipe J. Blas ◽  
María Carolina dos Ramos
Keyword(s):  
Equation Of State ◽  
Phase Equilibria ◽  
Excess Properties

Potential of group contribution methods for the prediction of phase equilibria and excess properties of complex mixtures

2003 ◽  
Vol 75 (7) ◽  
pp. 875-888 ◽  
Author(s):  
Jürgen Gmehling
Keyword(s):  
Equation Of State ◽  
Phase Equilibria ◽  
Equations Of State ◽  
Data Bank ◽  
Group Contribution ◽  
Proximity Effects ◽  
Excess Properties ◽  
Excess Enthalpies ◽  
Separation Processes ◽  
Group Contribution Methods

Reliable knowledge of the thermophysical properties of pure compounds and their mixtures in the whole composition and a wide temperature and pressure range is a vital prerequisite for computer-aided synthesis, design, and optimization of chemical processes. Knowledge of the various phase equilibria is most important for the development of thermal separation processes (but also for other applications,such as the design of multiphase reactors, the prediction of the fate of a chemical in the environment,etc.).Whereas 25 years ago, the main interest was directed to the development of predictive tools for vapor–liquid equilibria of subcritical compounds of similar size (ASOG, UNIFAC), 15 years later a proper description of the temperature dependence (excess enthalpies), the activity coefficients at infinite dilution, and solid–liquid equilibria of eutectic mixtures (including strong asymmetric systems) was achieved. After the combination with cubic equations of state [Soave–Redlich–Kwong (SRK), Peng–Robinson (PR)], the group contribution concept was extended to supercritical compounds [predictive SRK (PSRK)]. With the development of an adequate electrolyte model (LIFAC), the equation-of-state approach can even be used for systems with strong electrolytes. With the revision of the group interaction parameters, the extension of the parameter matrix (introduction of new structural groups, filling of parameter gaps), and the help of a large database (Dortmund Data Bank), the predicted results of group contribution methods were significantly improved and the range of applicability greatly extended. Furthermore, still-existing problems with the group contribution approach (proximity effects,etc.) were reduced.With the help of a volume-translated PR equation of state and application of temperature-dependent and improved mixing rules, the remaining weaknesses of group contribution equations of state (such as poor results for liquid densities, excess enthalpies, and the problems with asymmetric systems) were minimized.

Prediction of phase equilibria and excess properties for systems with sulfones

AIChE Journal ◽  
2003 ◽  
Vol 49 (2) ◽  
pp. 530-537 ◽  
Author(s):  
Roland Wittig ◽  
Jürgen Lohmann ◽  
Jürgen Gmehling
Keyword(s):  
Phase Equilibria ◽  
Excess Properties

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.

Sign in / Sign up

Export Citation Format

Share Document