CO₂ hydrate formation and dissociation are the fundamental processes for investigating hydrate-based carbon storage. To better understand CO₂ hydrate phase behaviors in the presence of surfactant and solid additives, this study reports the effects of Sodium Dodecyl Sulfate (SDS) and micron Cu particles on the formation of CO₂ hydrates in the presence of porous quartz sands in a lab-scale reactor. This research is part of a wider study focused on defining the properties of solid additives, produced via gas-atomization, on the formation and dissociation of gas hydrates. The morphology of CO₂ hydrate formed in SDS solution shows dispersed crystal particles due to the increase of surface tension. SDS works as the kinetic promoter on CO₂ hydrates formation whereas the addition of Cu particles inhibits CO₂ gas consumption. The mixture additives show a faint kinetic inhibit effect, in which the Brownian motion restrictions may be responsible for the inhibition of CO₂ hydrate production. The solid additives also showed a weak thermodynamic effect on CO₂ hydrate phase equilibrium.

This article consists of an experimental description about how the memory effect intervenes on hydrates formation. In particular, carbon dioxide hydrates were formed in a lab–scale apparatus and in presence of demineralized water and a pure quartz porous medium. The same gas-water mixture was used. Half of experiments was carried out in order to ensure that the system retained memory of previous processes, while in the other half, such effect was completely avoided. Experiments were characterized thermodynamically and kinetically. The local conditions, required for hydrates formation, were compared with those of equilibrium. Moreover, the time needed for the process completion and the rate constant trend over time, were defined. The study of these parameters, together with the observation that hydrates formation was quantitatively similar in both types of experiments, allowed to conclude that the memory effect mainly acted as kinetic promoter for carbon dioxide hydrates formation.