Rapid growth of CO2 hydrate as a promising way to mitigate the greenhouse effect

Abstract

Hydrate method to capture and store CO₂ under sea floor as one of the most novel and promising methods to deal with the greenhouse effect and reduce carbon emission has gained increasing attention nowadays. But how to grow CO₂ hydrate under promotion in confinement has rarely been exploited. Here the growth of CO₂ hydrate with tetrahydrofuran (THF) promoter in confinement was systematically investigated by molecular dynamics simulations, with the counterpart growth but without promoter as a comparison. With promoter, an obviously more rapid growth of CO₂ hydrate was observed and CO₂ molecules went inside water cages along with the THF ones but not gathered into bubbles during the formation of clathrate. However, the gathering of CO₂ bubbles in the system without promotion hindered the obvious formation of clathrate. The vivid movies and physical quantities were analyzed in detail in order to further unravel the physical mechanism of the growth process and the promotion effect of THF. The obtained simulation results proved that THF could indeed promote the confined growth of CO₂ hydrate by preventing the formation of large CO₂ bubbles, providing a theoretical foundation for the geological storage of CO₂ hydrate in permafrost areas and marine sediments.