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Equation of state for benzene for temperatures from the melting line up to 725 K with pressures up to 500 MPa
Monika Thol, Eric W. Lemmon and Roland Span
An equation of state (EOS) is presented for the thermodynamic properties of benzene that is valid from the triple point temperature (278.674 K) to 725 K with pressures up to 500 MPa. The equation is expressed in terms of the Helmholtz energy as a function of temperature and density. This formulation can be used for the calculation of all thermodynamic properties. Comparisons to experimental data are given to establish the accuracy of the EOS. The approximate uncertainties (k = 2) of properties calculated with the new equation are 0.1% below T = 350 K and 0.2% above T = 350 K for vapor pressure and liquid density, 1% for saturated vapor density, 0.1% for density up to T = 350 K and p = 100 MPa, 0.1 – 0.5% in density above T = 350 K, 1% for the isobaric and saturated heat capacities, and 0.5% in speed of sound. Deviations in the critical region are higher for all properties except vapor pressure.
Keywords: Benzene, equation of state, extrapolation behavior, Helmholtz energy, thermodynamic properties.