When blast furnace 2 in Duisburg-Schwelgern was finally fired up again at the end of September, it had completed an epic modernization process. The technical term for this process is ‘relining,’ and it comprised the refitting of the core unit as well as repair work on the auxiliary units. In addition, the cooling system was modernized, the cast house was renovated, and the hot blast stoves, the gas cleaning system, the slag granulator, and the expansion turbine all underwent repair work.
Optimizing the purity requirements for steel quality
Parallel to this work, ThyssenKrupp Steel Europe conducted modernization work on the neighboring continuous caster 1 in Beeckerwerth, Germany. This project had to be carried out while the blast furnace was offline to prevent major production downtime. As part of this modernization project, the company completely replaced the casting machine itself and invested in a new ladle turret and a tundish, including car, among other things. “This way we can optimize the purity requirements for the steel materials,” says Ingo Knopp, who is responsible for slab production in Beeckerwerth.
New cooling technology results in better quality
In addition, a new technology for cooling the hot strand was integrated into the system. According to Knopp, “Thanks to the dual air-water cooling system, we will be able to cool the slab more gently and accurately than with our previous water cooling system. A number of different zones along the width of each segment on the hot strand are now cooled individually, and the cooling process can be adjusted based on the quality of the steel and the width of the strand.” The technique helps to reduce edge defects – one of the main challenges involved in the continuous casting process – to an absolute minimum.
“This improves the surface quality of the slab and ultimately results in better quality coils,” says Knopp. And naturally, that is something that customers love to hear. “This modernization work not only ensures the continued profitability of the Duisburg location, it also increases the efficiency of our systems and the quality of our product portfolio,” says Head of Production at Steel Europe Dr. Herbert Eichelkraut.
This type of modernization work is not unusual. The logistics of this gigantic project, on the other hand, were definitely out of the ordinary – the team of the Duisburg-based steel producer alone was 300 employees strong. Around 1,100 external workers from around 100 German and international companies were on the job each day, working to ensure that production could start up again as soon as possible.
The all-round modernization work, which was meticulously organized, took a little over three months.
The modernization of Europe’s largest blast furnace and the neighboring continuous caster cost the company over 200 million euros.