PHASE-BEHAVIOR PREDICTION IN SUPERCRITICAL SYSTEMS USING GENERALIZED SOLUTE CRITICAL PROPERTIES

Trebble and Sigmund (1990) have recently published a generalized form of the Peng-Robinson (1976) equation of state in which binary interaction parameters are predicted as a function of the species critical volumes, dipole moments, and quadrupole moments. In this study, the critical properties of solutes heavier than normal hexane are correlated against molar mass, normal boiling temperature, and group type (i.e. paraffinic, olefinic, naphthenic or aromatic). This extension further facilitates the use of the generalized Peng-Robinson equation in calculating phase behaviour of supercritical systems in which solute critical properties are unknown or uncertain. Calculation of phase behaviour using the extended correlation is shown to be of the same quality as the previous generalization (which required solute critical constants) for 38 binary systems covering broad temperature and pressure ranges.