Effect of impurities on thermophysical properties and phase behaviour of a CO2-rich system in CCS

CO2 captured from flue gases may contain impurities such as O2, Ar, N2 and water. The presence of such impurities in the CO2 stream can lead to challenging flow assurance and processing issues. The aim of this communication is to present experimental results on the phase behaviour and thermophysical properties of carbon dioxide in the presence of O2, Ar, N2 and water. The effect of these impurities on density and viscosity was experimentally and theoretically investigated over the range of temperature from 243.15 K to 423.15 K up to 150 MPa. A corresponding-state viscosity model was developed to predict the viscosity of the stream and a volume corrected equation of state approach was used to calculate densities. Saturation pressures and hydrate stability (in water saturated and undersaturated conditions) of the CCS stream were also experimentally determined and modelled. This work shows that the thermodynamic models and approaches adopted were able to satisfactorily describe the thermophysical properties and phase behaviour of a typical CO2-rich stream resulting from flue gases.