Volumetric properties of supercritical carbon dioxide from volume-translated and modified Peng-Robinson equations of state

Abstract

Following three well-established approaches, different modifications have been proposed that significantly improve the Peng-Robinson EOS’s predictions of the volumetric properties of carbon dioxide in the supercritical region. By making use of 5301 experimental PVT data points of supercritical carbon dioxide (SC-CO2), three models have been developed based on the volume-translation concept, modification of the alpha function of the attractive term of the Peng-Robinson EOS and the addition of a third translation parameter to the EOS. The experimental data considered encompass a wide temperature and pressure range of 304.35-1,273.15 K and 7.38-800.00MPa, respectively. According to the results from several graphical and statistical analyses, the proposed models can reliably be employed for prediction and representation of the volumetric properties of SC-CO2 with AARDs below 1.3%. Comparisons have also been made with the modified Redlich-Kwong EOS as well as the standard reference multiparameter EOS developed by Span and Wagner, demonstrating the comparable accuracy of the proposed models, while offering notably simpler mathematical formulation.