Experimental determination of the critical line for (carbon dioxide plus ethane) and calculation of various thermodynamic properties for (carbon dioxide plus n-alkane) using the PSRK model

The binary (carbon dioxide + ethane) exhibits an unusual and interesting ph ase equilibrium behaviour especially in the critical region of the pure com ponents and their mixtures. The critical line of this system was determined by using a flow apparatus. The experimental results were compared with the predictive Soave-Redlich-Kwong (PSRK) model. In this paper the PSRK model was also applied to the calculation of critical points, (vapour + liquid) e quilibria, azeotropic points, excess enthalpies (H-E), excess volumes (V-E) , and Henry's coefficients (H-12) The investigated systems included (carbon dioxide + ethane, or propane, or rt-butane. or n-hexadecane). In the PSRK calculations only one pair of temperature-dependent interaction parameters is required for (carbon dioxide + an n-alkane). The calculated results were compared with experimental data. The relation of excess properties with ph ase equilibria in (carbon dioxide + ethane) was discussed in detail. (C) 20 00 Academic Press.