Improvement of predictive Soave-Redlich-Kwong (PSRK) equation of state for representing volumetric properties of carbon dioxide-expanded organic solvents

摘要

In this study, the volume translation correction is applied to the predictive Soave-Redlich-Kwong (PSRK) equation of state (EOS) for improving the prediction accuracy of liquid densities of carbon dioxide (CO2)-expanded organic solvents. A total of 23 CO2-expanded organic solvents including hydrocarbons, ketones, and esters are considered in our calculation. By applying the original PSRK EOS, the prediction accuracy of liquid density is only qualitative and the average deviation is about 15%. When applying the translated volumes proposed by Peneloux and Rauzy (1982) and Lin et al. (2006), significant improvements in prediction accuracy are obtained and the average deviation is reduced to 4% and 6%, respectively. To further enhance the predictive accuracy, one attempt has been made in this study to consider the translated volume of CO2 and organic solvent separately. With Peneloux and Rauzy's translated volume for organic solvent, an alternative translated volume for CO2 is developed and adopted. With this approach, satisfactory predicted results are obtained especially at higher pressures and the average deviation can be further reduced to 3%. The volume-translated PSRK EOS discussed in this study provides a simple, empirical and totally predictive approach to accurate representation of liquid densities of CO2-expanded organic solvents. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.