Energy-efficient storage of methane and carbon dioxide capture in the form of clathrate hydrates using a novel non-foaming surfactant: An experimental and computational investigation

In recent decades, both rising energy demand and increasing population have led to a significant increase in atmospheric carbon dioxide (CO2). Natural gas, the primary source of energy, and carbon capture and storage must therefore be managed efficiently. Gas hydrates have considerable potential for CO2 capture and energy storage since they can selectively absorb gas molecules and provide a large storage capacity. However, the slow kinetics of the hydrate formation constrained their commercial usage. Although surfactants have been investigated as effective additives to accelerate the rate of gas hydrate formation, intense foaming during the gas hydrate dissociation adversely affects the gas recovery factor. In this study, a novel anionic surfactant based on aconitic acid (ASA) was developed to improve the kinetics of methane and CO2 hydrates formation. The methane hydrate experiments indicated that, even at low concentrations, ASA significantly enhanced the kinetics of methane hydrate formation. The maximum water-to-hydrate conversion of 97 % and the highest storage capacity of 174 v/v were achieved using 50 ppm of ASA. Additionally, 99.1 v/v of storage capacity was achieved for CO2 hydrate in the solution containing 1000 ppm of ASA. Moreover, molecular dynamics simulation revealed that self-assembly behavior of ASA molecules increased the solubility of the gas molecules in the solution, provided more gas molecules for growing hydrate interface, and increased gas hydrate growth. Furthermore, no foam formation occurred in the ASA solution, even at high concentrations. These results show that ASA can be applied as an efficient and foamless gas hydrate promoter for methane storage and CO2 capture applications.