"A New Variant of the PC-SAFT EOS"
The PC-SAF EOS has been applied to model phase behavior of various types of systems, while it is also well-known that the PC-SAFT EOS has difficulties in describing some second-order derivative properties. In this work, the temperature and volume dependences of the PC-SAFT EOS have been analyzed based on the total reduced residual Helmholtz free energy from the well-established reference equations. Meanwhile, a practical procedure has been proposed to refit the universal constants of the PC-SAFT EOS with focus on describing vapor pressure and density. It is shown that the new universal constants have practically resolved the mostly criticized numerical pitfall, i.e. presence of more than three volume roots at real application conditions, and the non-physical phase equilibrium prediction from the original universal constants is also studied. Finally, the possibility of using the original PC-SAFT model parameters with the new universal constants has been investigated for the phase equilibria of the systems containing hydrocarbons, chemicals, water or polymers.