Kinetics and morphology study of hydrate formation from CO2-H2O emulsion in glass beads

The CO 2 -H 2 O emulsion has multiple advantages in forming hydrate, such as easily adjustable CO 2 -to-H 2 O ratio, large contact area, strong sweep efficiency, and ability to carry chemical agents, which holds great promise for large-scale solid CO 2 geological sequestration. This paper systematically investigates the kinetics of hydrate formation from CO 2 -H 2 O emulsion and the corresponding morphological features in glass beads under different pore sizes at 3.27–7.15 °C and 10–14 MPa. Quantitative results on CO 2 hydrate formation rates, quantities, conversion rates, and hydrate saturations are obtained. Overall, under multi-factors, the conversion rates of CO 2 hydrate range from 22.9 % to 56.3 %, and hydrate saturations range from 18.5 % to 45.4 %. Here, lower temperature and higher pressure can enhance hydrate formation and increase the final conversion rate. As the pore size decreases, CO 2 hydrate conversion ratio increases, but the formation rate shows a significant decline. Additionally, under flowing conditions, hydrate conversion rates are further increased to 44.4 %–76.5 %, and its enhancement mechanism has been observed and revealed. Even though CO 2 droplets remain spatially separated, hydrate formation still demonstrates remarkably rapid propagation. These results prove the potential of CO 2 emulsion as an excellent medium for CO 2 hydrate storage and provide a direction for more effective carbon storage.