dc.description.abstract | In this study, two predictive thermodynamic models were applied to predict the solubility of pure solid solute in supercritical carbon dioxide. One is the PSRK EOS (Predictive Soave-Redich-Kwong equation of state) and the other is the PR+COSMOSAC EOS. The PSRK EOS is based on the group contribution concept. The required critical properties and acentric factor of pure solid solute for PSRK EOS are also determined from group contribution methods (four different models are evaluated: JR, CG, MG and NNR) and PR+COSMOSAC EOS, due to the absence of experimental data in literature. The PR+COSMOSAC EOS utilizes quantum mechanical calculation results of molecules to predict phase equilibrium of fluids and does not required critical properties and acentric factor as input. However, it should be noted that the melting temperature and heat of fusion of solid solutes are necessary to estimate the solid phase fugacity in the solubility calculation for both EOS.
The solubility of 101 solid solutes in supercritical carbon dioxide is investigated in this study. Because of the missing parameter issue and lack of functional group definitions in group contribution methods, the PSKR EOS can predict solubility for only 59 solid solutes. The overall average logarithmic deviation (ALD-x) in solubility for these 59 solid solutes are 1.96, 1.41, 1.35, 1.47, 1.47 and 1.00 from PSRK-JR, PSRK-CG, PSRK-MG, PSRK-NNR, PSRK-PRCS and PR+COSMOSAC, respectively. The PR+COSMOSAC EOS, in general, provides more accurate results than group contribution methods. Since the PR+COSMOSAC EOS does not have the missing parameter issue, it can be applied to predict all solid solutes considered in this study and provide a similar accuracy (ALD-x = 0.92). In addition, the accuracy of six aforementioned approaches in predicting solubility of 23 solid solutes in supercritical carbon dioxide with 20 organic cosolvents (a total of 61 ternary systems) was also investigated. The PR+COSMOSAC EOS still provides the most accurate results (ALD-x = 0.71) in the ternary systems compared to those from PRSK EOS (ALD-x = 1.87, 1.32, 1.39, and 1.82 from PSRK-JR, PSRK-CG, PSRK-MG, and PSRK-NNR, respectively, for 18 solid solutes and a total of 53 ternary systems). This study shows that the PR+COSMOSAC EOS could provide useful information for design of industry process when no experimental data are available.
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