Cooperative effect of surfactant and porous media on CO2 hydrate formation and capacity of gas storage

Abstract

Hydrate-based technology is considered to be a promising approach widely applied in the areas of industrial natural gas storage and transportation, CO2 capture and storage. The major technical issues related to this technology are enhancing the formation rate and gas storage capacity under different conditions. In this work, the formation characteristics of CO2 hydrate were investigated in porous media below the freezing point in the presence of SDS (Sodium Dodecyl Sulfate). The influence of cooperative effect of surfactant and porous media on hydrate formation was investigated at different concentration of SDS. The results indicated that surfactant could obviously promote the formation process of CO2 hydrate in porous media when the concentration of SDS was in the range of 0–1240 ppm and the temperature ranged from 268.15 K to 272.15 K. However, there was an optimal SDS concentration to promote the formation process of CO2 hydrate in porous media below the freezing point. When the SDS concentration was 240 ppm, the highest conversion rate of ice to hydrate and the largest gas storage capacity were obtained, which were 43.05% and 80.06 L/L, respectively. The results also indicated that, with or without SDS in porous media system, the higher the temperature was, the less time it brought to reach 90% of the CO2 gas absorption (t90). But the maximum gas storage capacity of CO2 hydrate was obtained at 270.15 K in porous media in the presence of SDS. In addition, the results demonstrated that the SDS concentration of 0.24 g/L could increase the gas storage capacity of hydrate and shorten the value of t90 at different temperature conditions. These results are helpful for comprehensively understanding the rapid formation of CO2 hydrate in industrial areas and providing an important theoretical guidance and reference for the CO2 capture and storage in the form of hydrate.