Net zero Flow Assurance - Validation of various equations of state for the prediction of VLE and density of CO2-rich mixtures for CCUS applications

Abstract

Carbon dioxide management is becoming a major topic of interest in the energy industry and carbon capture is part of this process. Carbon capture utilization and storage is considered a promising technique to mitigate the impact of the hard-to-abate industries. Despite the high level of accuracy of predictions of the thermodynamic behaviour of pure CO2, there are still several uncertainties when dealing with CO2-rich mixtures. The impact of impurities in the captured stream can impact considerably the sizing and the design of components such as pipelines and related costs. The scope of this work is to assess the capabilities of the most acknowledged Equations of State (EoS) in the energy industry to predict CO2-rich mixtures behaviour. In this work we assess their accuracy in the prediction of Vapour-Liquid Equilibrium (VLE) and density validating numerical results with detailed experimental data available in literature. A quantitative estimation of deviations from experimental data is provided for density and bubble points. The results show that, based on experimental data available, multi-parameters Equations of State, such as GERG-2008 and CSMA, are generally more accurate in the description of both VLE and density if compared with cubic EoS.