Speaker
Description
With the growing importance of subsurface storage for clean fuels, hydrogen and ammonia have been proposed as promising candidates—hydrogen as a clean fuel and ammonia as a carbon-free energy carrier. A key concern, however, lies in the geochemical reactions that may occur between these injected fluids and host rocks in the presence of an aqueous phase. In particular, reactions with calcite can lead to carbonate dissolution and the formation of secondary phases such as CO₂. Understanding these processes is essential for evaluating the long-term impacts of fluid injection into porous media and for optimizing energy storage systems. This study explicitly models surface-reaction kinetics at the pore-scale, addressing a critical knowledge gap regarding the suitability of carbonate formations for subsurface ammonia or hydrogen storage. Hydro-chemical simulations were performed to investigate interactions between ammonia/hydrogen and calcite. Numerical experiments focused on a single calcite grain exposed, in two separate scenarios, to continuous aqua-ammonia flow and to continuous dissolved hydrogen flow. Results indicate that, under identical boundary and hydrodynamic conditions, the grain–hydrogen system undergoes substantially more aggressive dissolution than the grain–ammonia system. This contrast arises from differing local chemical environments: in the ammonia–water system, strong alkaline conditions (pH ≈ 11–12) develop, which suppress reaction rates and slow calcite dissolution, whereas in the water–hydrogen system, pH remains below 7, creating a more acidic environment that accelerates dissolution. A sensitivity analysis of ammonia injection rate further revealed that, although total calcite volume loss remains limited within the explored parameter range, higher injection rates lead to measurable increases in dissolution and associated microstructural changes.
| Country | Iran |
|---|---|
| Green Housing & Porous Media Focused Abstracts | This abstract is related to Green Housing |
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