Stability limits and Mechanical Behaviors of Methane Gas Hydrates for use in Greenhouse Gas Mitigation Technologies

With the increasing crises of global warming phenomenon, Carbon dioxide (CO₂) sequestration is an inevitable component during greenhouse gas mitigation. It aims to capture and store the CO₂ gases in the atmosphere. Gas hydrates are potential material for CO₂ sequestration due to their excellent storage capacity. The CO₂ sequestration process is based on SI methane gas hydrates; methane is replaced by carbon dioxide. The pressures and temperatures surrounding the gas hydrates change during this process, making the hydrate structure unstable. This contribution will present the pressure stability limits of monocrystal defect-free methane gas hydrates, using accurate density functional theory (DFT) to simulate the hydrate's performance under varying pressure. The effects of pressure on this guest-host crystal's geometric and atomic bonding features are presented and analyzed using various atomic angle and bond length distribution functions. Comprehensive characterization of the elastic properties with pressure is presented and related to the crystal geometry changes. Taken together, these results contribute to understanding the methane gas hydrate stability under a great range of pressures and provide a comprehensive prediction of the hydrate's performance during CO₂ sequestration.