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.