An Equation of State for Binary Fluid Mixtures to High Temperatures and High Pressures

Publisher Website
Google Scholar
Abstract
An equation of state has been constructed which can describe and predict phase equilibria and critical curves of fluid binary systems. The equation is particularly suitable for regions of elevated temperatures and pressures and for systems with molecules of high polarity, for example for aqueous systems. The computer simulation based Carnahan‐Starling term with temperature dependent particle diameter describes the repulsion. The attraction term uses a square well potential. The values of the parameters in the equation are derived from critical data of the pure mixture partners or have a defined relation to the chosen model of molecular interaction. Thus predictions are possible. The experimental critical curve of the H2O‐N2system to 250 MPa could be well represented with two adjusted parameters. With the same set of adjusted parameter values critical curves of the systems H2O‐CH4and H2O‐Xe have been calculated to 220 MPa. Critical curve and the binodal (phase‐equilibrium) surface in the pressure‐temperature‐composition diagram could be calculated for H2O‐CO2above about 500 K to 200 MPa with a different pair of mixture parameters. A comparison with other equations is made. The possibility to predict excess molar volumes of supercritical dense H2O‐CH4‐mixtures to 400°C and 150 MPa is demonstrated.

This publication has 40 references indexed in Scilit: