Industrial & Engineering Chemistry Research, Vol.37, No.5, 1663-1672, 1998
Gaussian-like volume shifts for the Peng-Robinson equation of state
The original form of the Peng-Robinson (PR) cubic equation of state does not predict liquid densities that are accurate enough to be used for process calculations. Liquid densities predicted by the PR equation have been improved by incorporating a Gaussian-like volume translation which is a strong function of temperature near the critical point but becomes a constant value away from the critical point, without any discontinuities in the critical region. This simple method provides liquid densities for 283 nonpolar, polar, and hydrogen-bonding fluids with an overall average absolute deviation of 0.70%, which compares favorably with existing volume translation and dedicated liquid density calculation methods.