Modeling the phase equilibrium of soybean oil deodorizer distillates plus supercritical carbon dioxide using the Peng-Robinson EOS

The Peng-Robinson EOS was used to predict vapor-liquid equilibrium (VLE) of the multicomponent mixture soybean oil deodorizer distillates (SODD)/CO2. The composition of SODD from the Cia. Riograndense (RS, Brazil) was used. S ODD was treated as a mixture containing fatty acids (palmitic, oleic, and l inoleic), sterols (stigmasterol), tocopherols (alpha -tocopherol), and squa lene. The interaction parameters were obtained from solubility and/or VLE d ata available in the literature for the binary pairs of SODD compounds/carb on dioxide. For the binary systems SODD compound i/SODD compound j, the int eraction parameters were set equal to zero. The results were compared with literature data using distribution coefficients and selectivities. The sele ctivity was calculated by reducing the mixture to a pseudo-binary system co ntaining a light and a heavy compound. The modeling of the system SODD/CO2 using the Peng-Robinson EOS has proven to be a powerful tool for obtaining preliminary information of VLE of complex systems and for guiding experimen tal vapor-liquid equilibrium measurements.