Effects of 2,5-Dihydrofuran on Hydrate Equilibrium Dissociation Conditions of CO2

Hydrate has advantages in the field of CO2 capture and sequestration, cold storage, etc. But CO2 hydrate formation needs very strict conditions, such as high pressure or low temperature conditions. 2,5-Dihydrofuran is used as a thermodynamic promoter to improve CO2 hydrate equilibrium conditions. At any temperature, the experimental results show that the equilibrium pressure of CO2 + 2,5-dihydrofuran + H2O is much lower than that of CO2 in pure water. The CO2 + 2,5-dihydrofuran + H2O system forms a structure II hydrate, while CO2 forms a structure I hydrate in pure water. With more addition of 2,5-dihydrofuran (>10 wt %), the reduction of hydrate formation pressure decreases at any experimental temperatures. At lower pressures, 2,5-dihydrofuran exhibits the properties of a water-soluble thermodynamic promoter, while at higher pressures, it shows the properties of an insoluble thermodynamic promoter.