Flameless Metamorphosis: CO₂-Neutral Steel Heat Alchemy

LOIImage Source: Tenova


Tenova LOI Thermprocess, in collaboration with thyssenkrupp Hohenlimburg GmbH, achieves a groundbreaking milestone in steel production. A bell-type annealing plant, utilizing Tenova's Ultra low NOx HPH®-flameless technology, has successfully heat-treated 70 metric tons of steel strip using up to 100% hydrogen—a world-first in locally CO₂-neutral processing. The innovative flameless concept demonstrates remarkable low NOx emissions, showcasing the compatibility of CO₂-neutral heat treatment with minimal nitrogen oxide impact.


In a pioneering collaboration, Tenova LOI Thermprocess and thyssenkrupp Hohenlimburg GmbH redefine the landscape of steel production. Traditionally operated with natural gas, bell-type annealing plants play a crucial role in shaping the mechanical properties of steel coils. Tenova's latest generation heating hoods, featuring the patented Ultra low NOx HPH®-flameless concept, have already proven their worth at thyssenkrupp's Hagen-Hohenlimburg site, yielding energy and CO₂ savings of up to 12% over 12 years.

As part of a joint project to decarbonize steel production, the partners embarked on a significant campaign involving multiple annealing cycles. In a groundbreaking move, the fuel gas supply for heat-treating hot-rolled narrow strips transitioned from natural gas to up to 100% hydrogen, a world-first in locally CO₂-neutral processing. Despite the higher combustion temperature of hydrogen, Tenova's HPH®-flameless technology showcased remarkably low NOx emissions, affirming its compatibility with sustainable steel production.

For flexible fuel delivery, a specially designed mobile natural gas/hydrogen mixing station facilitated the annealing process, assessing the impact of increased hydrogen admixtures. This forward-looking initiative not only embraces decarbonization but also aligns with thyssenkrupp Steel Europe's long-term strategy to achieve climate neutrality in downstream production processes by 2045.

Jan Bernhofen, Team Coordinator Processing at thyssenkrupp Hohenlimburg GmbH, emphasizes that the project is integral to the company's decarbonization strategy, aiming for climate-neutral steel production. Dr. Gökhan Gula, Project Manager and Process Engineer at Tenova LOI Thermprocess, underscores the technical complexity of hydrogen combustion and the project's role in advancing insights into the decarbonization of the annealing process.


In a remarkable feat, the collaboration between Tenova LOI Thermprocess and thyssenkrupp Hohenlimburg GmbH has ushered in a new era for steel production. The successful heat treatment of 70 metric tons of steel strip using up to 100% hydrogen in a bell-type annealing plant marks a pivotal step towards CO₂-neutral processing. The innovative Ultra low NOx HPH®-flameless technology not only demonstrated low NOx emissions but also showcased the compatibility of hydrogen combustion with the intricate annealing process. This initiative aligns with thyssenkrupp Steel Europe's broader decarbonization strategy, envisioning climate-neutral steel production by 2045.

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