LD converters (also known as BOF converters) continue to be a crucial component in the steelmaking process, and with recent advancements in green steelmaking technologies, their importance is set to persist in the future. As a result, optimizing the LD converter process, improving equipment design, and executing revamp projects will stay on our agenda. Given that the LD process is already highly mature, future improvements are primarily aimed at enhancing quality—such as through better bottom stirring or KOBM—boosting productivity, and reducing CO2 emissions by increasing the scrap rate. For the equipment, the focus is on improving reliability, enhancing the operator experience, and minimizing manual labor, for instance by using measuring manipulators. A prime example of such improvements is the revamp of the 330-ton BOF at ArcelorMittal Ghent, where an optimized project execution strategy was employed, incorporating a specialized logistical solution.
Challenge
The main goal of the ArcelorMittal Ghent project was to completely replace the existing converter while maximizing the reuse of existing equipment and refining its design. Key elements of the project included the introduction of a new vessel with an optimized shape, a detachable bottom, and advanced lip ring cooling. The trunnion ring was also redesigned, featuring water-cooled trunnions and improved manholes for easier access. Additionally, the project incorporated the Vaicon Link 2.0 vessel suspension system, which uses horizontal links positioned above the trunnion ring to maximize space for piping. The reliable Vaicon Drive was used for tilting the converter during tapping and charging, and the converter’s main bearings and pedestals were also upgraded. One notable feature of the revamp was the reinstallation of the existing Vaicon Stopper, which had been supplied by Primetals Technologies in 2013, after it underwent maintenance.
The manufacturing and logistical approach for the project was designed to minimize on-site activities. ArcelorMittal Ghent’s location, with its own harbor capable of handling large and heavy equipment, provided an advantage for transporting oversized components. However, a pipe bridge along the route from the harbor to the converter shop posed a significant height limitation. To address this challenge, it was decided that the converter shell would be split into at least two parts, with a separate upper cone, to reduce the overall height. Evaluations showed that it would be possible to transport the fully assembled converter to the harbor, but due to the pipe bridge, the top cone would need to be removed before transport. The optimal solution, as determined through cost analysis, was to preassemble the vessel without the top cone at the workshop and then lift it above the pipe bridge using an enormous 1,000-ton crane.
LD converter body in front of pipe bridge
LD converter body over pipe bridge
Solution
The entire process of replacing the converter—from the final heat with the old vessel to the handover for relining of the new vessel—was completed in just 35 days. Key steps included cooling and cleaning the old converter, removing refractory material, opening the doghouse, cutting and removing the old tilting drive, and moving the old converter to the charging bay. Civil work was carried out on the converter foundation before installing the new pedestals and placing the new converter on rails. The converter was then lowered and fixed in place, followed by the installation of the new tilting drive and the reinstallation of the Vaicon Stopper. The vessel’s top cone was then moved into position and welded before cold testing was conducted and the first heat charged.
LD converter at erection in the Steelmaking Shop
Results
This revamp of the 330-ton LD converter at ArcelorMittal Ghent illustrates how design optimization, combined with a specialized logistical solution, enabled a successful and efficient upgrade. By reusing key components such as the Vaicon Stopper and minimizing on-site work through premanufacturing and preassembly, the revamp was completed in a record time of 35 days. This accomplishment was made possible thanks to the excellent cooperation of all parties involved.
LD converter first heat at ArcelorMittal Ghent
Video
LD Converter (BOF) supplied to ArcelorMittal in Ghent - Timelapse
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Benefits
- Optimized process execution: The implementation of a specialized logistical solution and an optimized project plan led to an efficient revamp of the BOF converter.
- Cost and time savings: Minimizing on-site work through prefabrication and preassembly allowed the project to be completed in just 35 days.
- Reuse of existing components: The Vaicon Stopper from 2013 was reused after maintenance, saving costs and making efficient use of resources.
- Better accessibility for maintenance: The project focused on improving maintenance accessibility, which will reduce operational costs in the long term.
Conclusion
- BOF converter revamp: The 330-ton BOF converter at AM Ghent was successfully revamped, incorporating design optimization and specialized logistics, allowing for efficient project execution and completion in just 35 days.
- Key design improvements: The project introduced a new vessel with an optimized shape, detachable bottom, advanced cooling systems, and improved accessibility features for maintenance.
- Logistical efficiency: The use of AM Ghent's own harbor and careful planning allowed oversized components to be transported efficiently, despite challenges like the pipe bridge height limitation.
