A new equation of state : theory and experiment

Abstract

Representation of thermodynamic properties is needed to design chemical processes. In this work, a theoretically based equation of state is formulated to represent the PVT behavior of pure fluids. The new equation of state is based upon the augmented van der Waals theory and predicts the behavior of pure spherical and non-spherical molecules over a wide range of fluid densities at high and low pressure in the single and two phase regions. Accurate saturated liquid densities and vapor pressures can be predicted with the new EOS. Also, excellent estimates of the second and third virial coefficient are possible with this equation of state. Additionally, accurate density measurements of dichlorodifluoromethane (R-12) and chlorotrifluoromethane (R-13) between 230 and 475 K and from 0.7 to 67 MPa are made using a direct weighing method. The estimated accuracy of these measurements is 0.2%.