Formation and dissociation of CO2 hydrates within a natural basaltic-based porous medium from Icelandic margins.

Carbon dioxide hydrates were formed and dissociated in a lab-scale apparatus, filled with demineralised water and porous sediments. Two different porous media were tested; the first consists of glass beads, commonly used to reproduce marine environments during lab-scale hydrate formation experiments. Natural basaltic sand, typical of the Icelandic margins, was chosen as second sediment. The role played by the two sediments, was analysed both during the hydrate formation and dissociation processes and the results were compared among each other. In particular, the pressure – temperature values measured during the dissociation phase, were compared with the phase boundary equilibrium conditions for pure carbon dioxide hydrates, carried out in absence of any porous sediment, collected from the scientific literature.