NWO-DFG, Fluidization Technology for Regeneration of Hydrogen-based Iron Fuel

• Applicant: Professor Dr.-Ing. Stefan Heinrich
• Subject Area: Energy Process Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 575570236

Climate change necessitates an energy transition from fossil fuels to renewable energy. Due to fluctuating availability of energy resources such as solar and wind, the global energy transition requires innovative energy carriers for decentralized, long-term, and long-distance storage and transportation to complement the future energy mix. Iron powder has emerged as a clean, safe, and cost-effective energy carrier, particularly because of its high (volumetric) energy density. It releases chemical energy through oxidation with air or reaction with water, generating high-temperature heat and/or hydrogen. The resultant iron oxide powder can be regenerated into iron via chemical reduction using (green) hydrogen generated from renewable energy. This cyclical oxidation-reduction process, known as the Iron Power Cycle, establishes a circular, CO2-free energy economy. While development of iron combustion technology has grown rapidly with MW-scale fluidized bed boiler demonstration, development of green iron fuel regeneration (iron oxide reduction) technology is lagging. This proposal focuses on the regeneration/reduction challenges in fluidized beds. Fluidization technology has a wide application in chemical engineering, energy conversion, and pharmaceuticals production. Because of its advantage in high heat and mass transfer rates between the fluid phase and solid phase, it is very attractive and has been preliminarily investigated for the regeneration process in the Iron Power Cycle. The aim of this project is to leverage the fundamental understanding of reactive, cohesive particulate flows in fluidized bed H2-ironmaking process towards the industrial application of Iron Power Energy Cycle. With a novel experimental setup for the first time, the collision and consequent sintering of laser heated particles will be measured with two high-speed cameras. Furthermore, the most suitable fluidized bed configuration for this H2-DRI process will be examined. The fluidization regimes to be investigated include bubbling regime, spouted fluidization and fast fluidization. The experiments will provide datasets of cohesive particle collision and reactive gas-solid flow dynamics in different fluidization regimes, which are essential for development and validation of numerical models. Finally, effective numerical tools with generic modules should be established which are applicable beyond this project towards wide applications involving dense gas-solid flows with phase transition and chemical reactions. Despite a focus on scientific impact, this project will, in the long term, also generate impact on technological development (increasing TRL) and implementation of the Iron Power Cycle as well as green steelmaking. The research employes a combined experimental and numerical approach. At Hamburg University of Technology, the work focuses on experiments. At Eindhoven University of Technology, the focus will be on numerical model development and CFD-DEM simulations.

• DFG Programme: Research Grants
• International Connection: Netherlands
• Partner Organisation: Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
• Cooperation Partner: Professorin Dr. Yali Tang