Evaluating the gas storage capacity of 1,3-dioxolane–hydrogen binary hydrates via molecular simulations

Abstract

H2 is a green fuel with high energy density, but its efficient storage and transportation remain challenging. Clathrate hydrates are promising materials for H2 storage. In this study, molecular simulations are conducted to evaluate the gas storage capacity of 1,3-Dioxolane (DIOX)–H2 hydrate under various thermodynamic conditions. Results reveal that the growth rates of DIOX–H2 and tetrahydrofuran (THF)–H2 hydrates exhibit similar trends to those of pure DIOX and THF hydrates with temperature, indicating that the growth processes of the binary hydrates are dominated by DIOX and THF. However, their growth rates are almost constant with pressure of 10–110 MPa at 250 K. H2 can significantly improve the growth rate of hydrates due to its small size and high mobility. Furthermore, temperature has little effect on the gas storage capacity of the binary hydrates, but an increase of pressure significantly enhances it. Although DIOX is more efficient than THF in promoting the growth of hydrates, the gas storage capacity of DIOX–H2 hydrate is weaker. The gas occupancy of 512 cages is the key factor determining the gas storage capacity of the binary hydrates. Multiple H2 occupancies can be found in 51264 cages at high pressures. This study provides molecular-level insights into the hydrate growth process, which can serve as a guide for improving the gas storage capacity of hydrates.