Low hydrogen solubility in clay interlayers limits gas loss in hydrogen geological storage

TA Ho and CF Jove-Colon and YF Wang, SUSTAINABLE ENERGY & FUELS, 7 (2023).

DOI: 10.1039/d3se00363a

Gas intercalation into clay interlayers may result in hydrogen loss in the geological storage of hydrogen; a phenomenon that has not been fully understood and quantified. Here we use metadynamics molecular simulations to calculate the free energy landscape of H-2 intercalation into montmorillonite interlayers and the H-2 solubility in the confined water; in comparison with results obtained for CO2. The results indicate that H-2 intercalation into hydrated interlayers is thermodynamically unfavorable while CO2 intercalation can be favorable. H-2 solubility in hydrated clay interlayers is in the same order of magnitude as that in bulk water and therefore no over-solubility effect due to nanoconfinement is observed - in striking contrast with CO2. These results indicate that H-2 loss and leakage through hydrated interlayers due to intercalation in a subsurface storage system, if any, is limited.

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