CO2 and CO2-Rich Stream Hydrate Formation in Equilibrium with Brines in the Context of CO2 Injection

This work investigates the effects of salt solutions composed of NaCl, KCl, CaCl₂, MgCl₂, and Na₂SO₄ on hydrates of CO₂ and CO₂-rich streams. Measurements were made using the isochoric pressure-search method up to 43 MPa between 251 and 292 K. The obtained data were compared with predictions from a thermodynamic model using the Cubic-Plus-Association equation of state (EoS). In all cases, the hydrate-forming conditions were modeled with the solid solution theory of van der Waals and Platteeuw. A thermodynamic consistency analysis was performed by using linear regression fitting. The results indicate that the stabilities of CO₂ and CO₂-rich hydrates are significantly influenced by the concentration of salt solutions. These findings contribute to a better understanding of hydrate formation and dissociation conditions in CO₂ and CO₂-rich streams, particularly when injected into saline aquifers for Carbon Capture, Utilization, and Storage (CCS) applications.