Simulation insights into wetting properties of hydrogen-brine-clay for hydrogen geo-storage

Journal of Energy Storage, Journal Year: 2025, Volume and Issue: 112, P. 115477 - 115477

Published: Jan. 27, 2025

Language: Английский

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Structural and dynamical properties of aqueous NaCl brines confined in kaolinite nanopores

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(12)

Published: March 24, 2025

Quantifying thermodynamics, structural, and dynamical properties of brine confined in clay pores is critical for a variety geo-energy applications, including underground hydrogen storage (UHS) carbon capture sequestration (CCS). Atomistic molecular dynamics simulations are applied here to study aqueous NaCl brines within 10-Å kaolinite slit pores. concentrations chosen at 5, 10, 12.5, 15 wt. %, all below the solubility limit high enough provide statistically relevant information. The distribution ions nanopores found not be homogeneous. Explicitly, Na+ cations, preferentially attracted siloxane surface, accumulate regions with low water density, whereas Cl− anions, gibbsite surface kaolinite, hydration layers. Confinement affects ions, ion pairing being more pronounced pore than bulk solutions similar temperatures, pressures, compositions. Conversely, affect water. For example, lifetime water–water bonds confinement shortened shells; increasing salinity from 5 12.5 % reduces likelihood density fluctuations near surfaces, although when concentration rises anions enhance layer surface. simulated trajectories studied further extract diffusion coefficients. While nanopore mobility species, non-monotonic trends observed as function salt concentration. seem associated pairing. Furthermore, coefficients cations predicted higher those which contrary what typically brines. Because correlated such gases water, our observations may have important implications applications UHS CCS.

Language: Английский

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Wettability of Chemically Heterogeneous Clay Surfaces: Correlation between Surface Defects and Contact Angles as Revealed by Machine Learning

ACS Applied Materials & Interfaces, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

Quantifying the wettability of clay surfaces and how it changes in presence gas mixtures is crucial for designing geo-energy applications such as underground hydrogen storage carbon capture sequestration. While computational studies exist atomically perfect mineral substrates, actual minerals possess heterogeneities. This study employs molecular dynamics simulations to examine impact surface defects on kaolinite exposed hydrogen, methane, dioxide. The results show that siloxane become more hydrophilic defect densities increase gases can strongly affect wettability. Carbon dioxide, particular, shows stronger adsorption heterogeneous than methane. As a consequence, dioxide Additionally, our higher salt concentrations reduce water contact angle, which important because likely present subsurface. A machine learning classification algorithm applied interpret develop predictive capabilities. Our findings highlight importance wettability, essential geological repositories ranging from enhanced recovery sequestration intermittent storage.

Language: Английский

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Roles of kaolinite-oil-gas molecular interactions in hydrogen storage within depleted reservoirs

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: unknown, P. 156452 - 156452

Published: Oct. 1, 2024

Language: Английский

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