Effect of 1,3-Dioxolane on Gas Separation Kinetics via Gas Hydrates

The mixed gas separation of hydrate technology can promote biogas separation, purify CO2, and improve the quality of CH4 while reducing carbon emissions and realizing efficient CO2 capture and storage. Herein, we identified the effects of low-content 1,3-dioxolane (DIOX) on the separation efficiency and kinetics of a CH4/CO2 (6:4) mixture via gas hydrates. The experimental results showed that the hydrate formation with DIOX had five stages. The purification rate of CH4 could be effectively accelerated with the increase in DIOX concentrations. At 4.5 MPa and 274.65 K, the induction time of hydrate formation could be reduced by 93.3% compared to that of the pure water system. However, higher driving forces could lead to dense hydrate film and reduce the separation efficiency of CO2/CH4. The suitable pressure and temperature (e.g., 4 MPa, 274.65 K) could alleviate this problem, and it could result in a CO2 recovery of 92.2%. When the gas–liquid ratio was 3.5, the CO2 recovery could be increased by 23% and the CO2 phase equilibrium constant could be increased by 2.8 times compared to that of the pure water system.