Abstract
Underground hydrogen storage has been the subject of extensive research recently. Hydrogen diffusion coefficient into brine critically affects hydrogen loss. However, the available data pertain to hydrogen diffusivity in pure water or NaCl solutions, with rare interpretations of temperature and salinity effects. In this paper, molecular dynamics simulations at realistic conditions were conducted to calculate these coefficients in various brines, particularly those containing divalent salts. The results indicate lower diffusivities at higher salinities and lower temperatures, the value being 7.29 × 10−9 m2/s at 323 K, increasing to 10.2 × 10−9 m2/s at 353 K for 1 molal NaCl solution. The diffusion coefficient decreases up to 38 % as the salinity increases from 1 to 5 molal. Besides, hydrogen diffusivity in MgCl2 solution is up to 60 % smaller than in NaCl solutions at the same molality. Radial distribution functions and hydrogen bond analyses confirm the results. This research provides new data for estimating hydrogen loss in aquifers or water-saturated caprocks.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.