The expected outcomes from this project include:
- Better understanding of the needs for thermal storage pertaining to each use-case, including technical requirements, key performance criteria, site specific factors, integration requirements/challenges, value proposition.
- A clear technology landscape for high-temperature TES options, and an evaluation (via SWOT analysis) of how they fit with the needs of HILT CRC end users.
- Flow sheets modelling integration of hot stored iron ore into a fluidised bed H2-DRI process.
- Simplified system performance model of PB-TES systems for integration to alumina/lime calcination processes.
- Techno-economic assessment of the storage and integration options.
- Evaluation of the technical challenges and risks.
- Recommendations for any future HILT CRC investment in research and/or demonstration of high-temperature TES, on the basis of the findings of the Scoping Study and Case Studies.
Phase 1 of RP2.009 was completed in September 2024, and phase 2 (RP2.017) is underway.
RP2.009 examined two case studies for thermal energy storage integration to HILT processes in depth:
- retrofit of high-temperature thermal storage to a calciner in an alumina refinery
- supply of heat to a hydrogen fluidised bed direct reduction process, for iron making.
For alumina, heat is required at a temperature around 1000°C. Hot blast stoves are regenerative heating systems used for heating air that is fed into blast furnaces in steelmaking, and an example of a fully commercial system designed for heating air at the temperatures required.
This project investigated the feasibility of repurposing hot blast stoves for longer-term storage, and electrical heating. The encouraging results indicated that the concept could potentially displace about one-third of energy normally provided by natural gas. Phase 2 is investigating further options for deeper levels of gas replacement, in both retrofit and new build cases.
For iron ore, the research team developed an initial flow sheet integrating thermal storage. The cost of heat supply from this route was about 23% cheaper compared to a reference case in which heat was provided by burning hydrogen. There are opportunities to further increase this benefit, and these are being further developed in phase 2.
