This involves shifting from coal-powered blast furnaces that use coal as a reduction medium to a direct reduction process using hydrogen produced via renewable energy. The first HYBRIT pilot plant in Luleå, Sweden began operations in 2020, with commercial-scale production targeted by 2027.

Kanthal is proud to have contributed to HYBRIT’s groundbreaking journey by developing an electricity-based process gas heater for the hydrogen-based direct reduction process under the name Prothal®. This project showcased the feasibility of fossil-free industrial heating solutions and laid the groundwork for scaling up these technologies to meet the steel industry's future needs.

A vision for fossil-free steel

Traditional steelmaking methods rely heavily on coal, significantly contributing to global CO₂ emissions. HYBRIT seeks to phase out coal by using hydrogen in the reduction process, producing water as a byproduct instead of CO₂.

A key aspect of this vision is an emissions-free heating technology. Kanthal’s renowned expertise in industrial heating has led to the development of a gas-heating solution entirely powered by electricity.

The role of Kanthal electric process gas heaters

Kanthal's process gas heater, Prothal®, in HYBRIT's pilot plant.Kanthal’s team worked closely with HYBRIT to design, install, and test electric gas heaters concept capable of heating hydrogen gas to the high temperatures required for the direct reduction process.

The Kanthal solution uses metallic resistance materials as heating elements and structural components. This innovative approach minimizes heat loss, reduces design complexity, and ensures high efficiency.

The developed heater concept can handle several gas mixtures, including 100% hydrogen, hydrogen-nitrogen (H₂-N₂) blends, and air. It is designed to operate at extreme temperatures, reaching up to 1,000°C (1,832°F), making it highly adaptable for direct reduction.

Development and testing: A stepwise approach 

The journey from concept to implementation involved rigorous development and testing carried out in three phases:   

Laboratory-scale heater

The initial prototype, with a 200–400 kW capacity, was developed and tested in Kanthal’s laboratories. Practical tests and computer simulations validated its design and performance.

Pilot heater

The next phase involved installing a similar 200–400 kW heater in a subset of the gas circuit in HYBRIT’s pilot plant. This allowed the team to evaluate functionality under varying conditions, such as gas flow, pressure, and composition.

Full-scale pilot heater

The final phase saw the installation of a 1 MW heater in the main gas circuit. This heater successfully heated pure hydrogen gas in campaigns up to 950°C (1,742°F), demonstrating good temperature stability and high efficiency (95%). It operated seamlessly as part of HYBRIT’s direct reduction process, proving its ability to handle varying gas mixtures and flow rates.

Results and impact

The electric gas heater has proven to be a viable alternative to fossil-fueled heating systems. During the pilot tests, it demonstrated:

• Zero greenhouse gas emissions during operation (when powered by renewable electricity).

• High efficiency, minimal energy waste.

• Successful integration into the direct reduction process as part of a cohesive production system.

Beyond technical achievements, the project provided valuable know-how regarding process integration, control, and regulation. These learnings will be critical for scaling up the technology to meet the demands of industrial-scale steelmaking. 

The Swedish Energy Agency has recognized the importance of this work, emphasizing its role in transitioning the steel industry toward sustainability.

A broader vision for electric heating

The HYBRIT project primarily focuses on ironmaking, but Kanthal’s electric gas heater, Prothal®, has potential applications that extend well beyond this sector.

The HYBRIT project primarily focuses on ironmaking, but Kanthal’s electric gas heater, Prothal®, has potential applications that extend well beyond this sector. Industries requiring high-temperature gas heating, such as petrochemicals, cement, and many more, can greatly benefit from this technology. Fossil-free electric heating provides a sustainable alternative to traditional heating methods in various industrial processes.

Next steps: Scaling up for the future

The pilot project’s success has set the stage for further development. The next phase will focus on industrializing the electric gas heater concept, and one vital part is optimizing the heater’s design to ensure cost-effective production, high availability, and superior performance. Moving on, addressing challenges and refining design criteria for large-scale industrial deployment will be the top priorities.

These advancements will support the HYBRIT initiative and position Kanthal’s electric heating solutions as a cornerstone of sustainable practices. As industries globally strive to decarbonize, this technology provides a pathway to achieve both environmental and commercial objectives.