Accurate calculation and reliable prediction of second virial coefficients for nonpolar mixtures

Abstract

The virial equation of state has a theoretical advantage in the calculations of mixtures. The second mixture virial coefficients are with the theoretically rigid mixing rules and composed of the second virial coefficients for pure fluids and the cross second virial coefficients. Based on the generalized corresponding state principle second virial coefficient model for pure fluids we proposed before, the generalized cross second virial coefficient models were established with three characteristic parameters for nonpolar binaries in this work. The calculation of the mixture critical temperature requires the binary interaction coefficients (k_ij). The mixture acentric factor was determined by the arithmetic mean. The mixture critical pressure could be calculated without the critical specific volume. For the most sensitive mixing rule of the mixture critical temperature, the k_ij was optimized for 145 nonpolar binaries. An easily accessible characteristic correlating parameter, the reduced diameter, was proposed to develop the predictive k_ij correlations for common nonpolar binaries. Due to the complex intermolecular interactions between two different molecules, the k_ij correlations were proposed respectively for alkane/alkane binaries, nonpolar binaries containing fluorocarbon, nonpolar binaries containing nitrogen or oxygen, nonpolar binaries containing simple fluids, nonpolar binaries containing carbon dioxide and nonpolar binaries containing neon. Our work was validated to perform satisfactorily from the comparison with the Chueh-Prausnitz k_ij correlation, Fender-Halsey k_ij correlation, and Meng k_ij correlation. Together with our previous work, this work could accurately calculate and reliably predict the second virial coefficients for common nonpolar mixtures.