Impact of hydrogen storage on the characteristics and mechanical properties of trona deposits

Abstract

Underground hydrogen storage (UHS) represents a promising avenue for storing excess energy for future use. To ensure the safe implementation of this technology, it is crucial to evaluate the potential alterations hydrogen might induce in the host rock. This research studied the impact of hydrogen (H₂) on the mechanical properties of trona rock collected from Sweetwater County, Wyoming, USA. Twelve cylindrical specimens were prepared: three with a diameter of 25 mm and nine with a diameter of 38 mm. Specimens underwent treatment with gas compositions of 50 %H₂ and 100 %H₂ over two weeks, under 4 MPa of pressure and at room temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and both uniaxial and triaxial compression tests were performed. Trona specimens treated with 50 %H₂ and 100 %H₂ exhibited, on average, 14 % and 33 % lower triaxial compressive strength, respectively, than that of untreated specimens. However, the elastic modulus of specimens treated with 50 %H₂ and 100 %H₂ increased by an average of 88 % and 166 %, respectively, compared to untreated specimens. This study shows that the rock's mechanical properties and microstructure are influenced by the reaction between H₂ and trona-related minerals.