An improved volume translation strategy for PR EOS without crossover issue

For the most nonlinear temperature-dependent volume translation techniques, there is a crossing of isotherms in the pressure-volume (PV) diagram, which leads to thermodynamic inconsistency, gives anomalous prediction of some physical properties and thereby restricts the applicability of the volume translated equation of state (EOS). In this work, a generalized nonlinear temperature-dependent volume translation model is developed for PR EOS to achieve more accurate prediction of the liquid densities for pure components. Based on a criterion we have derived in a prior work, a mathematical constraint is applied when the model parameters are being regressed to match the measured density data; by adopting this criterion, we ensure that no any crossover phenomenon occurs for the new volume translation model over a wide range of pressure and temperature (up close to 100 MPa and 1000 K). The model parameters are determined based on the regression of the density data of 17 non-polar and slightly polar substances. It is shown that the new consistent volume-translated PR EOS improves the accuracy in calculating the liquid density for the 17 substances with an overall absolute average percentage deviation of 1.44%.