Revised parameters and typical results of the VTPR group contribution equation of state

Group contribution methods like UNIFAC or modified UNIFAC and group contribution equations of state such as PSRK and VTPR are ideal tools for the development of the different processes in chemical industry, where the latter methods have the advantage that they can be applied for supercritical compounds. With the development of VTPR the weaknesses of the PSRK model (poor results for activity coefficients at infinite dilution, excess enthalpies, asymmetric systems, liquid densities) were as far as possible removed.With the application for systems with strongly polar compounds, such as water, alcohols, etc., the VTPR model had to be revised. For example new fragmentation rules and van der Waals surfaces had to be used, and further thermophysical properties and a sophisticated procedure had to be applied for the simultaneous fit of the temperature-dependent group interaction parameters to a comprehensive data base.In this paper the required parameters for different group combinations are given. Furthermore the quality of the results of the group contribution equation of state VTPR is demonstrated on various examples of industrial interest.

► An extended mod. UNIFAC (Do) fragmentation was introduced in the VTPR-GC-EOS.
► The parameter fitting procedure is explained in detail.
► New and revised parameters for 65 group combinations are given.
► Adjusted van der Waals group surface parameters are given.
► Typical results of the group contribution equation of state VTPR model are shown.