Date of Award
2025
Document Type
Thesis - ECU Access Only
Publisher
Edith Cowan University
Degree Name
Doctor of Philosophy
School
School of Engineering
First Supervisor
Stefan Iglauer
Second Supervisor
Alireza Keshavarz
Third Supervisor
Peter Behrenbruch
Abstract
Underground Hydrogen Storage (UHS) offers a potential solution for clean fuel and promises to replace traditional fossil fuels, significantly reducing CO2 emissions. Geological formations such as depleted oil/gas reservoirs, deep saline aquifers and shale formations have been recognized as potential targets for injecting and storing H2, subsurface situations which have sufficient storage capacity and geological stability. Depleted hydrocarbon reservoirs are considered to be an excellent solution due to inherent advantages when executing a large-scale UHS. However, H2 flow properties under various geo-storage conditions during injection and production cycles have not been investigated widely when compared to natural gas or CO2. Furthermore, due to the highly diffusive nature of H2, the risk of leakage and loss during underground storage and transportation still raises many concerns about implementing UHS. Hence, a comprehensive understanding of multiphase flow properties, such as interfacial tension and diffusion coefficients in the presence of H2 is vital for assessing and storing H2 safely and efficiently in geological formations. This thesis aims to investigate typical influences of interfacial tension and diffusion when blending H2 with cushion gas (CH4, CO2, N2) in different geo-storage situations, and with natural gas in various transport conditions. The presented research used molecular dynamics (MD) simulation to investigate interfacial tension and self-diffusion in binary systems (H2-H2O, H2-CH4, and H2-N2) and ternary systems (H2- CO2-H2O, H2-N2-H2O and H2-CH4-H2O) at temperatures from 300 K to 373 K and a pressure range of 1 to 70 MPa. Findings revealed that interfacial tension is a function of pressure, temperature, and H2% mixing with cushion gas. However, at elevated pressure (over 50 MPa), the interfacial tension was found to be independent of temperature and pressure. Furthermore, it was found that H2 self-diffusion in methane and nitrogen is a function of pressure and temperature, but H2 self-diffusion in water depends only on temperature. Additionally, the degree of H2 self-diffusion in water is slower than in cushion gas. The thesis provides extended or new data on interfacial tension and self-diffusion for various Hydrogen storage and transportation conditions. Moreover, results obtained can aid in de-risking large-scale UHS projects, providing more secure and effective means of implementation.
DOI
10.25958/hxzc-1185
Access Note
Access to this thesis is embargoed until 25th October 2026
Recommended Citation
Doan, Q. (2025). Hydrogen geo-storage: Prediction of fundamental parameters using molecular dynamics simulations. Edith Cowan University. https://doi.org/10.25958/hxzc-1185
Comments
Author also known as Trevor Doan