Lavoro presentato alla Conferenza “First Conference on Chemical and Process Engineering”, Firenze, 13-15 maggio 1993. -
This paper is related to the phase behavior prediction of an oil fraction in supercritical solvents.
The supercritical fluids investigated in this work are n-hexane and n-heptane using equilibrium data from our laboratory and from literature .
We can consider the oil fraction, (boiling point range: 230-350°C), made by two homogeneus subfractions, a paraffinic-like fraction and an aromatic-like fraction.
These cuts can be obtained by chromatographic separation (1) and analyzed by simulated distillation.
From the informations obtained throught analytical data is possible to find two components, having the same molecular weight of the fraction, one paraffinic and one aromatic, for representing the two subfractions .
The procedure, tested in previous works (2, 3), considers a thermodynamic model (PHCT equation) proposed by Cotterman et al. (4).
The parameters of the pure component have a physical meaning and they can be correlated with the molecular weight within an homologous class.
From the knowledge of these properties and by means of experimental binary data, from literature, of the two systems, solvent with paraffinic and aromatic compound, it is possible the calculation of the PHCT binary interaction coefficients.
Starting from these binary coefficients we can predict the phase behavior of the solvent-oil fraction system.
