FAITH AND MOBILITY OF HYDROGEN IN GEOLOGICAL POROUS MEDIA
Master thesis
Permanent lenke
https://hdl.handle.net/11250/3056780Utgivelsesdato
2022Metadata
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- Studentoppgaver (TN-IEP) [323]
Beskrivelse
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Sammendrag
Large-scale hydrogen storage can help alleviate the main drawbacks of renewable energygeneration, their intermittency, and their seasonal and geographical constraints. Renewableenergy without energy storage is unable to satisfy the whole system’s energy demand.Excess renewable energy can be converted to hydrogen through electrolysis (“greenhydrogen”) and stored to be used during periods of high energy demand. Even hydrogengenerated from hydrocarbons, in combination with Carbon Capture and Storage, (“bluehydrogen”) can help to reduce emissions in the energy sector while transitioning towards alow-carbon industry. Expectations for energy storage are high but large-scale undergroundhydrogen storage in porous media (UHSP) have not been deeply understood. To facilitatehydrogen supply on the scales required for a zero-carbon future, geological storage inporous media, such as saline aquifers and depleted hydrocarbon reservoirs can be a valuableoption.Despite the vast opportunity provided by UHSP, the maturity is considered low, and as suchUHSP is associated with several uncertainties and challenges. Some of them are theselection of the most suitable cushion gas for maintaining sufficient operational pressure,the rate of injectivity, different physical and chemical properties compared to othergeologically stored fluids, and the possible reaction of hydrogen with subsurface mineralsand fluids affecting the storage options.In this project, attempts are made to have a deeper look into the surface and downholeparameters that must be considered for the safe storage of H2 in geological porous mediaand transfer the knowledge or lesson learned from the CO2 storage sites. Comparing andidentifying the element of the storage risks, a general scheme for a safe hydrogen injectionand reproduction in geological porous media will be proposed and certain recommendationswill be made.The hydrogen storage was created in the synthetically created infinite-acting aquifer usingCMG-GEM software to run the simulation and WINPROP-CMG to model the fluidparameters. The hydrogen was injected in the middle of the aquifer with residual brine inthe porous medium. The options with three different water salinity levels and variousstorage scenarios including multiple operations cycles in the presence of prior cushion gasinjection and methanation reaction were considered and the efficiency of hydrogen storagewas evaluated.In a case of five cycles of injection and production with the interval of 12 months led todecreased water production rate over time in the absences of a cushion gas and brinesalinity. As a cushion gas, the nitrogen and carbon dioxide were chosen to be tested. It canbe beneficial to inject nitrogen during various cycles in order to reduce the water productionrate but may not be the best choice if brine salinity rises. Carbon dioxide was injected toinitiate the methanation reaction which occurs after the following hydrogen injection toyield methane.Injection of CO2 proved to be the most effective way to remove water from the wellboreregion. However, due to high costs associated with assembling the installation system fortransporting liquid CO2, the first few extraction cycles may be problematic for CO2injection. In the best scenario, less saline aquifers with cyclic hydrogen injection andproduction with CO2 cushion gas were found to be the most efficient.