Evaluation of Cubic, SAFT, and PC-SAFT Equations of State for the Vapor–Liquid Equilibrium Modeling of CO₂ Mixtures with Other Gases

Abstract

Accurate thermodynamic models for phase equilibria calculations of carbon dioxide mixtures with other gases are of high importance for the safe and economic design of carbon capture and storage (CCS) technologies. In this work, we assess the capability of Redlich−Kwong (RK), Soave−Redlich−Kwong (SRK), Peng−Robinson (PR) cubic equations of state (EoS), as well as Statistical Associating Fluid Theory (SAFT) and Perturbed-Chain SAFT (PC-SAFT) in modeling vapor−liquid equilibria for binary mixtures of CO 2 with CH 4 , N 2 , O 2 , SO 2 , Ar, and H 2 S, and for the ternary mixture CO 2 −N 2 −O 2 . Liquid density calculations for some of these mixtures are also performed. Experimental data available are used to assess the accuracy of the models. Two different expressions are used for the calculation of parameter α in PR EoS. PC-SAFT is, on average, more accurate than cubic EoS and SAFT when no binary interaction parameter is used. However, when a binary interaction parameter fitted to the experimental data is used, model correlations from SRK, PR, SAFT, and PC-SAFT are of comparable accuracy.

An integrated, multi-scale modelling approach for the simulation of multiphase dispersion from accidental CO2 pipeline releases in realistic terrain

“…These quantities can be derived from the equation of state and greatly affect the predictions of rate of pipeline depressurization during accidental release. As a result, accurate modelling is critical to hazard identification studies, and prediction and validation of the derivative properties has been documented ( ; Diamantonis et al, 2013). Finally, the newly proposed equation of state combined with existing semiempirical transport-property models were validated for viscosity and the self-diffusion coefficient.…”

Molecular simulation of the thermophysical properties and phase behaviour of impure CO2 relevant to CCS

“…There are complex EoS for CO 2 mixtures, including the SAFT 14 , PC-SAFT 15 , GERG 12 , EOS-CG 6,16 and Demetriades models 10 . Some comparisons to CCS-relevant measurements have been made 6,10,17 .…”

“…The SAFT family of EoS 14,15 has a basis in physical modelling, meaning they have the potential to address some of these issues. However, they still require fitting to experiments and it is not yet clear whether these outperform empirical EoS in terms of accuracy and robustness 6,10,17 . There is a clear need for modelling based on robust physical and chemical principles to complement EoS approaches.…”

Hybrid fluid–structure interaction modelling of dynamic brittle fracture in steel pipelines transporting CO 2 streams

“…To calculate properties of the liquid and vapour phases and their equilibrium mixtures formed during the CO 2 pipeline decompression, the PC-SAFT equation of state is applied (Diamantonis et al, 2013). This equation of state has proved to provide superior accuracy in predicting the thermodynamic data for multi-component CO 2 mixtures covering the regions of vapour-liquid equilibria (VLE) of relevance for CCS transportation pipelines (Diamantonis and Economou, 2011).…”