German forging company Schmiedewerke Gröditz (SWG) operates a 50-tonne electric arc furnace (EAF) for manufacturing and processing blanks across various weight categories. The EAF’s roof was completely lined with refractory material. This has now changed with a series of upgrades by KSK during the furnace’s shutdown at the turn of the year 23/24.
The new year began with a mission accomplished for KSK, an engineering firm from Germany. KSK and SWG successfully started up the new, water-cooled furnace roof, which includes a system of pipes, a slag chamber and a recooling circuit.
The new roof replaces the old refractory design. It is built with a water-bearing structure consisting of inner and outer collector/distributor pairs with connecting lines. Water-cooled pipe panels are incorporated into the structure, forming the furnace roof together with the refractory centrepiece. The furnace roof exhaust manifold used for purging the fumes generated in the production process is attached to the roof’s gantry and can be separately replaced.
The first section of the downstream primary gas de-dusting system (hot gas line) was also upgraded as part of the conversion. From the furnace roof exhaust manifold, a water-cooled exhaust pipe with a water-cooled, adjustable swivel joint extends into a fireproof slag dust chamber with a water-cooled hinged door.
All the water-cooled components of the furnace roof and the downstream primary gas de-dusting system are designed with pipes and incorporated into a closed recooling system. This technology has proven successful in most German and European electrical steel plants, undergoing continuous expansion and development over the course of decades.
The recooling system is powered by a KSK pump station. The station, including the control cabinets, is pre-assembled on a steel frame and, after connection to water and electricity, is immediately ready for use. Its features include its own water treatment (descaling) system, frequency-controlled pumps and leak detection (accurate down to a few litres). The cooling circuit is recooled via a modular dry cooler with EC motor control.
When combined, the components and recooling system ensure that the low-maintenance furnace can operate safely without causing issues. Its properties include:
- Water-cooled components lasting significantly longer than in the refractory version
- Improved extraction performance with slag discharge
- Safe furnace operation thanks to KSK leak detection accurate down to the single-digit litre range
- Adjustable temperature level control at constant supply temperature
- Easy-to-repair water-cooled components thanks to modular element design
- Virtually repair-free pipe system operation due to closed cooling circuit
- Sustainable water management without water losses or use of biocidal products/other chemical additives
- Waste heat can be extracted
- High quality made in the German towns of Haltern am See and Brandenburg an der Havel
“Needless to say, other concepts and companies were also options on the table for the planned EAF conversion”, reveals SWG project manager Matthias Pfennig, adding that the decisive factor for SWG’s decision was ultimately “the closed cooling system’s ease of maintenance and reliability.” “In bringing KSK on board, we were able to work with proven specialists who also fit in well with our way of working.”
KSK project manager Michael Rosenthal is also satisfied with how the project went: “The planning, which lasted just under a year, and subsequent implementation across the assembly and start-up stages were carried out collaboratively and without any major incidents. Exactly how it should be!”
