Properties of CO₂ Mixtures and Impacts on Carbon Capture and Storage

The technologies for CO₂ capture and storage (CCS) differ much in design, operation conditions, and the amount and nature of impurities in the captured CO₂. The presence of impurities affects the thermophysical properties of CO₂ significantly. In particular, properties such as phase equilibrium behavior, density, viscosity, thermal conductivity, and diffusion coefficient are much affected. The development and technical breakthrough of new CCS technology rely on a deeper understanding of the thermophysical properties of CO₂ mixtures. In this chapter, the available experimental data and theoretical models about the thermodynamic and transport properties of mixtures at conditions relevant to CCS have been summarized. Knowledge gaps have been identified; in particular, more measurements are needed to close the experimental gaps. In addition, the impacts of impurities on operation of different CCS processes have been discussed, including CO₂ conditioning, compression, liquefaction, transport, and storage. Recommended levels of impurities from different sources have been reviewed and compared.