Pressure, volume, temperature, and composition measurements and thermodynamic properties of water + n-heptane mixtures in the supercritical region

摘要

A new set of experimental pressure, volume, temperature, and composition data for water, n-heptane, and their mixtures at supercritical conditions is reported. The measurements were made with a constant-volume piezometer in a precision thermostat. The measurements cover the temperature range 573-673 K and the pressure range 4-30 MPa. The overall accuracy of the pressure, density, temperature, and concentration measurements are within ±0.15, ±0.2, ±10 mK, and ±0.002 mole fraction, respectively. The partial and excess molar volumes, excess Gibbs energy, and activity coefficients of n-heptane in supercritical water were calculated by the use of the experimental results.