Review on CO₂ hydrate formation/dissociation and its cold energy application

Carbon dioxide hydrate has been paid growing attention due to its application potentials like being used as a secondary refrigerant and sequestration in the deep ocean. Therefore, there has been a lot of research on various gas hydrates, including methane hydrate, ethane hydrate, methane-CO₂ mixture hydrate and so on. However, there is no review especially on the CO₂ hydrate and its cooling application. In this paper, the review provides the comprehensive understanding of the CO₂ hydrate with focus on the formation and dissociation models, including the kinetic and thermodynamic ones, as well as its applications. It is proposed that more experimental and modeling work should be carried out on CO₂ hydrate dissociation, and the kinetic models should be developed by considering the effect of additives. It is also proposed that the cooling application of CO₂ hydrate will become popular in the very near future and therefore, the experimental data at low pressure are needed. Finding the effective additives which can reduce the equilibrium conditions and increase the kinetic formation/dissociation rate is recommended.