New Insights into the Kinetics and Morphology of CO2 Hydrate Formation in the Presence of Sodium Dodecyl Sulfate

This work reports an experimental investigation on the morphology and kinetics of CO2 hydrate formation in the presence of sodium dodecyl sulfate (SDS). The experiments were conducted at 277.15 K and 3.5 MPa, and the quantity of SDS varies from 0 to 3000 ppm. The “wall climbing” phenomenon of CO2 hydrate formation in the presence of SDS was observed, and the growth of CO2 hydrate above the gas–liquid interface was found to become stronger as the SDS concentration was increased from 300 to 3000 ppm. This indicates that the promoting effect of SDS on CO2 hydrate formation was enhanced with the increase of SDS concentration. The largest gas consumption for CO2 hydrate formation in SDS solutions was obtained at 1500 ppm of SDS among the four SDS concentrations tested in this work, which increased by 85% compared to that obtained in pure water under the same temperature and pressure conditions. When CO2 hydrate formation was conducted for a considerably long period, two rapid jumps in the gas consumption could be observed as the SDS concentration increased above 300 ppm, and the plateau between the two jumps was shortened with the increase of SDS concentration. As a result, a high efficiency for CO2 hydrate formation was obtained at 1500 and 3000 ppm of SDS. This will provide an implication to the improvement of the hydrate-based CO2 capture technology in the future.