HYDRA places the DR-EAF route at the center of its strategy to support the transition toward carbon neutral steel production. In this approach, Direct Reduced Iron (DRI) is produced in a dedicated Direct Reduction Plant (DRP) and then fed—together with scrap—into the Electric Arc Furnace (EAF), where final melting and refining occur. This integrated pathway is among the most promising alternatives to conventional BFBOF steelmaking for reducing CO₂ emissions while enabling flexibility in material inputs and energy sources.
 

At pilot scale, HYDRA leverages both units—DRP and EAF—to generate high quality experimental data and validate process models. The DRP allows systematic variation of chemical composition, temperature, and flow conditions to evaluate DRI quality. The EAF pilot setup enables controlled testing of feeding strategies, arc behavior, melting dynamics, and final steel performance. Together, these capabilities provide a robust foundation for scalable industrial innovation. 

A core pillar of HYDRA’s approach is advanced process modeling, essential to understanding the underlying physics, thermochemistry, mass and energy balances, and system level interactions. Modeling supports operational decisions, increases process efficiency, and enables reliable scaleup of carbon neutral steelmaking technologies. 

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A wide spectrum of model types—computational fluid dynamics (CFD), thermodynamic models, numerical and physical models, data driven tools, and hybrid approaches—is needed to capture the complexity of EAF operations. While CFD offers deep insight into localized phenomena (e.g., oxygen jet penetration, multiphase flow, arc–metal interaction), it remains limited by its computational intensity, incomplete boundary conditions, and scarcity of high quality validation data from inside the furnace. This highlights the value of models based on mass and energy balances, which provide a broader perspective on process optimization, cost reduction, and sustainability. 

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Looking ahead, the shift toward DRI intensive and hydrogen based routes requires new modeling capabilities beyond conventional scrap based assumptions. Priority research areas include: 

• DRI feeding behavior, including DEM–CFD coupling for granular and thermal interactions. 

• Fragmentation and carryover of fine DRI, with implications for slag foaming and oxidation. 

• Electrode configuration and electromagnetic modeling to predict arc stability, melting profiles, and stirring patterns. 

• Mixed burden behavior (scrap+DRI), impacting melting rates, slag chemistry, and H2 control. 

• HDRI charging, requiring transient heat transfer and melting front models. 

• Integration of machine learning models for process prediction, adaptive control, and energy optimization. 

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In conclusion, HYDRA’s work on EAF process modeling lays the groundwork for the next generation of flexible, efficient, and low-carbon steelmaking solutions. By combining experimentation with advanced multiscale modeling, the project strengthens the technological readiness of the DR-EAF route and provides actionable insights for industry stakeholders committed to achieving sustainable production.