The Bilstein Group has converted a complete heating hood with eleven burners and 1,800 kW heat output from natural gas to hydrogen operation at its Hagen-Hohenlimburg site. There was no loss of performance in the process, the company reports.
Bilstein has now been able to implement what it claims is the world's first CO2-neutral heat treatment with 100 t of cold strip. Hydrogen-capable recuperation burners from Küppers Solutions were used.
On May 15 and 16, 2023, the commissioning of the converted heating hood took place after two years of research and development work.
"Not a single gram of natural gas"
"From the ignition of the burners to the end of the process, we did not burn a single gram of natural gas and achieved excellent process parameters. As a result, we were able to save around 3,700 kg of CO2 locally in this trial alone. Water vapor came out of the chimney instead of CO2," explains Christian Hagenkord, Head of Sustainability Projects and Energy Supply at Bilstein.
This was confirmed by the Gas- und Wärme-Institut Essen e.V. (GWI), which provided metrological support for the project.
Before the pandemic, the parent company Bilstein achieved a production volume of 500,000 t per year. If the company were to switch completely to hydrogen, this would result in potential savings of 25,000 t of CO2. This would be equivalent to the annual CO2 consumption of around 2,300 people living in Germany.
Technical details
Since the volumetric calorific value of hydrogen is only one-third that of natural gas, around 5,600 m³ of hydrogen was needed instead of 1,870 m³ of natural gas to anneal the approx. 100 t of cold-rolled strip for several hours at a temperature of 710 °C. The hydrogen is used to heat the strip.
Westfalen provided the quantity of hydrogen required for the practical test and corresponding truck trailers from which the hydrogen was fed directly into the piping systems of the hood annealing plant. At peak times, more than 600 m³ of hydrogen per hour had flowed directly from the trailer to the Bilstein plant.
Kueppers Solutions burners in use
Following a successful feasibility study in mid-2022, the decision was made at the end of 2022 to convert a heating hood on a test basis to dual operation with natural gas or hydrogen. Together with Kueppers Solutions GmbH from Gelsenkirchen, it was possible to "significantly further develop" the existing burner technology.
It was the use of 3D printing that made it possible to implement new burner designs and bring them to market. The burner mouth in particular is produced by metallic 3D printing in the new, complex burner shape. The same material (2.4856 Inconel 625) is used as for the engine blades of the Airbus A380.
