Non–isothermal two–phase hydrogen transport in rock salt during cycling in underground caverns

• Published in: International journal of hydrogen energy 2021-02, Vol.46 (9), p.6632-6647
• Main Authors: AbuAisha, Murad, Rouabhi, Ahmed, Billiotte, Joël, Hadj–Hassen, Faouzi
• Format: Article
• Language: English
• Subjects: Cavern thermodynamic state; Engineering Sciences; Environmental Sciences; Fluids mechanics; Mechanics; Saturated rock salt; Thermo–hydraulic coupling; Two–phase hydrogen percolation and diffusion; Underground salt caverns
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.11.152

For a good management and precise tracks of hydrogen quantities stored in salt caverns, this paper presents a study on hydrogen transport in rock salt during cycling. It provides a novel mathematical–numerical model that couples the cavern thermodynamics with the transport mechanisms of hydrogen in the saturated rock salt in a fully coupled thermo–hydraulic framework. Both the two–phase Darcian percolation and the Fickian diffusion are used to account for hydrogen migration in the interstitial brine of the rock salt. Due to the absence of experimental data, a parametric study is furnished. The effect of cycling within the cavern on the migration mechanisms is discussed in detail. Simulations have confirmed the dependency of the Darcian percolation on the model parameters. However, for similar applications, this dependency might be limited. The value of the Fickian diffusion coefficient affects indirectly the Darcian percolation. The two–phase percolation becomes more of a piston–like for very small values of the diffusion coefficient. On a real–scale typical cavern, and over a period of 40 years, simulations have proven that the quantity of hydrogen lost into the surrounding rock salt is unimportant. Besides, cycling renders this quantity more insignificant. 1) The cavern thermodynamic state is coupled with the non-isothermal two phase flow of hydrogen in the rock salt 2) The mass of hydrogen exchanged with the rock domain is quantified. [Display omitted] •Hydrogen migration in the context of underground storage is presented.•Transport mechanisms between the cavern phases are discussed.•Cavern thermodynamics is coupled with the transport mechanisms.•Model parameters effects are investigated in a parametric study.•Cycling simulations proved that the amount of lost hydrogen rests negligible.