Applications of the Peng-Robinson equation of state

The Peng-Robinson (PR) equation of state (EOS) applies well to all light hydrocarbon processes, such as natural gas processing and light ends processing in refinery gas plants. For hydrogen-rich systems the accuracy for the hydrogen solubility may be improved by using a different alpha formulation or one of the more advanced mixing rules.

Using the PR EOS for the prediction of mixture properties involves two steps. First, we must "tune" the component acentric factor, a(Tr), for each component such that we accurately predict the component vapor pressure. Secondly, we determine the kij terms from experimental data for the binary system with components i and j such that the phase equilibria matches.

This EOS gives accurate predictions for nonpolar mixtures of hydrocarbons.

In addition to K-values (kij), you can use the PR EOS to predict the enthalpies, entropies, and densities for the liquid and vapor phases.