scholarly journals Equation of state for thermodynamic properties of chain fluids near-to and far-from the vapor–liquid critical region

1999 ◽  
Vol 111 (13) ◽  
pp. 5964-5974 ◽  
Author(s):  
Jianwen Jiang ◽  
John M. Prausnitz
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Critical Region ◽  
Chain Fluids ◽  
Vapor Liquid

A Rational Equation of State for Water and Water Vapor in the Critical Region

1964 ◽  
Vol 86 (3) ◽  
pp. 320-326 ◽  
Author(s):  
E. S. Nowak
Keyword(s):  
Water Vapor ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Critical Point ◽  
Critical Region ◽  
Constant Pressure ◽  
Parametric Equation ◽  
Enthalpy And Entropy ◽  
Specific Volumes

A parametric equation of state was derived for water and water vapor in the critical region from experimental P-V-T data. It is valid in that part of the critical region encompassed by pressures from 3000 to 4000 psia, specific volumes from 0.0400 to 0.1100 ft3/lb, and temperatures from 698 to 752 deg F. The equation of state satisfies all of the known conditions at the critical point. It also satisfies the conditions along certain of the boundaries which probably separate “supercritical liquid” from “supercritical vapor.” The equation of state, though quite simple in form, is probably superior to any equation heretofore derived for water and water vapor in the critical region. Specifically, the deviations between the measured and computed values of pressure in the large majority of the cases were within three parts in one thousand. This coincides approximately with the overall uncertainty in P-V-T measurements. In view of these factors, the author recommends that the equation be used to derive values for such thermodynamic properties as specific heat at constant pressure, enthalpy, and entropy in the critical region.

Renormalization Group Theory Applied to the CPA Equation of State: Impacts on Phase Equilibrium and Derivative Properties

2019 ◽  
Author(s):  
Gabriel Silva ◽  
Charlles Abreu ◽  
Frederico W. Tavares
Keyword(s):  
Renormalization Group ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Chemical Engineering ◽  
Equations Of State ◽  
Thermodynamic Description ◽  
Critical Conditions ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Vapor Liquid

Calculation of thermodynamic properties such as vapor-liquid phase behavior with equations of state is largely and successfully employed in chemical engineering applications.<br>However, in the proximities of the critical point, the different density-fluctuation scales inherent to critical phenomena introduce significant changes in these thermodynamic properties, with which the classical equations of state are not prepared to deal.<br>Aiming at correcting this failure, we apply a renormalization-group methodology to the CPA equation of state in order to improve the thermodynamic description in the vicinity of critical points.<br>We use this approach to compute vapor-liquid equilibrium of pure components and binary mixtures, as well as derivative properties such as speed of sound and heat capacity.<br>Our results show that this methodology is able to provide an equation of state with the correct non-classical behavior, thus bringing it in consonance with experimental observation of vapor-liquid equilibrium and derivative properties in near-critical conditions.

Thermodynamic Property Calculation in Vapor-Liquid Equilibrium for Multicomponent Mixtures using Highly Accurate Helmholtz Free Energy Equation of State

2021 ◽  
pp. 108-121
Author(s):  
T. Luo ◽  
A.Yu. Chirkov
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Energy Equation ◽  
Helmholtz Free Energy ◽  
Multicomponent Mixtures ◽  
Liquid Equilibrium ◽  
Equilibrium Calculation ◽  
Vapor Liquid Equilibrium ◽  
Vapor Liquid

Thermodynamic properties of multicomponent mixtures in phase equilibrium were studied. The tangent plane criterion was used for stability analysis, and the Gibbs energy minimization was employed for phase equilibrium calculation when the successive substitution didn't converge. Thermodynamic properties of a 12-component natural gas mixture in vapor-liquid equilibrium were calculated with highly accurate Helmholtz free energy equation of state GERG--2008, simplified GERG--2008 and common cubic Peng --- Robinson (PR) equation of state. Results show that in vapor-liquid equilibrium, GERG--2008 has high accuracy and works better than simplified GERG--2008 and PR-equation of state. Simplified GERG--2008 and PR-equation of state both work unsatisfactorily in vapor-liquid equilibrium calculation, especially near the saturation zone. The deviation function in GERG--2008 can significantly affect the accuracy of GERG--2008 when calculating thermodynamic properties of mixtures in vapor-liquid equilibrium

Reference correlations for the viscosity and thermal conductivity of fluids over an extended range of conditions: hexane in the vapor, liquid, and supercritical regions (IUPAC Technical Report)

2015 ◽  
Vol 87 (3) ◽  
pp. 321-337
Author(s):  
Richard A. Perkins ◽  
Marcia L. Huber ◽  
Marc J. Assael ◽  
Efthimia K. Mihailidou ◽  
Sofia K. Mylona ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Reliable Data ◽  
Theoretical Knowledge ◽  
Technical Report ◽  
Wide Range ◽  
Extended Range ◽  
Vapor Liquid

AbstractThis article summarizes the correlation procedures developed for IUPAC Project 2012-040-1-100 [Reference correlations for the thermal conductivity and viscosity of fluids over extended range of conditions (vapor, liquid and supercritical regions)]. This project is focused on the development of wide-range reference correlations for the thermal conductivity and viscosity of fluids that incorporate as much theoretical knowledge of these properties as possible. The thermal conductivity and viscosity correlations developed here for pure fluids are functions of temperature and density. The best available equations of state for a given fluid are used to calculate the thermodynamic properties required for these correlations, often from measured temperatures and pressures. The correlation methodology developed during this project has been applied to hexane in this report but can be applied to any pure fluid with a reliable equation of state and reliable data for the thermal conductivity and viscosity over a significant range of temperatures and densities.

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