At SSAB Luleå, Sweden, SMS group commissioned a modernized converter shop and the associated environmental technology. SSAB fully achieved its target of increasing the yield of both converters while meeting high environmental standards.
SMS group supplied two converter vessels with lamella suspension and the tilt drive systems. The twin-motor tilt drive systems are easily accessible and very maintenance-friendly. The scope of supply also included the converter trunnion bearings, the height increase of the existing trunnion pedestals, and the installation of the vessels and trunnion rings.
With the design developed by SMS group, the new converter vessels have become significantly larger: With an unchanged quantity of charge material of up to 130 tons, the internal volume of the converter has been increased by 10 percent. The additional capacity enables the process control to be made more environmentally friendly and energy to be recovered.
The increase in capacity was was realized by making better use of the installation space. This is made possible possible by the lamella converter suspension system developed and patented by SMS group. This is a maintenance-free converter mounting for a constraint-free arrangement of the converter vessel in the trunnion ring.
The converters can withstand the thermal loads due to the lamella suspension system, the design of an enlarged clearance and the use of high-grade heat-resistant fine-grained structural steels. This is achieved without additional cooling fluids – cooling by the natural thermal is sufficient. The design is part of the Ecoplants solutions. With this label, SMS group distinguishes technologies that work demonstrably efficiently and at the same time make a contribution to environmental protection.
SMS group has also revamped the primary gas cooling system of the BOF steelmaking plant. The cooling stacks of both converters were modified in a first phase and equipped with maintainance-friendly Baumco adjustable skirts from SMS group. These are hydraulically lowered to the converter mouth during the blowing phase. In this way, primary gases can be efficiently extracted while combustion is suppressed. Diffuse dust emissions are significantly reduced.
The SMS group's scope of supply and services included the revamp of the primary gas cooling system as well as the engineering and supply of the major cooling stack components. These incorporated the adjustable skirts with labyrinth seals. In addition, the inlet section in the washing tower was modernized. The steam produced in the cooling stacks is used as process steam in the entire integrated iron and steel plant.
The steam produced in the cooling stacks is used as process steam in the complete steel mill. The entire energy recovery of the two cooling stacks is thus operated in an extremely energy-efficient manner.
"We are highly satisfied with the Ecoplants technology and we have a clean environmental conscience as regards production", is the opinion of Kurt Lindqvist, Project Manager of the Converter Shop at SSAB Luleå.