Prediction of Thermodynamic Properties of CO2 by Cubic and Multiparameter Equations of State for Fluid Dynamics Applications

摘要

This paper makes a comprehensive analysis of equations of state (EOS) for the prediction of thermodynamic properties of CO2 which play a key role in fluid dynamics calculations: molar volume, throttling temperature, inversion curve, and velocity of sound. The cubic EOS Peng-Robinson and Soave-Redlich-Kwong are compared with the multi-parameter Huang and Sterner and Pitzer EOS. We further propose a method to compute the throttling temperature, which relies on the residual property, unlike the usual practice which solely computes the Joule-Thomson coefficient or the inversion curve. The predicted properties are compared with experimental data from literature to verify the best EOS at different temperatures and pressure conditions for each investigated property. The Huang EOS is the best at predicting the molar volume, especially in supercritical conditions, and the inversion curve. The cubic EOS predict the throttling temperature with greater accuracy. The Sterner and Pitzer EOS outperforms the others when predicting the velocity of sound, especially in conditions near and above the critical point. These multiparameter EOS seem to balance the trade-off between complexity and accuracy. These findings might be useful for designing and monitoring processes that use CO2 over a wide range of temperature and pressure conditions.