At SSAB Luleå, Sweden, SMS group (www.sms-group.com) has successfully commissioned the modernized converter shop and the pertaining environmental technology. SSAB fully achieved its own target of increasing the yield of both converters and satisfying the high environmental standards demanded.
Kurt Lindqvist, Project Manager of the Converter Shop at SSAB Luleå, is highly satisfied with the performance of SMS. “The proven technology of SMS provides very good results. Furthermore, the cooperation and communication during the erection and commissioning went very smoothly in an atmosphere of strong team spirit.”
SMS group supplied two converter vessels with lamella suspension and the tilt drive systems. The two-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.
Thanks to the design concept 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 more environment-friendly process control and efficient energy recovery.
This increase in capacity was achieved by improved utilization of the existing installation space. This was possible thanks to the lamella converter suspension system developed and patented by SMS group. It is a maintenance-free converter suspension system designed for arranging the converter vessel in the trunnion ring without restraint.
The converters are well prepared for the thermal loads thanks to the use of the lamella suspension system, along with the design of a larger clearance and the use of high-grade heat-resistant fine-grained structural steels. This is achieved without any additional cooling fluids; sufficient cooling is ensured merely by the natural thermal conditions.
SMS group's Ecoplants solution comprised the revamp of the primary gas cooling system of the BOF steelmaking plant. For this, the cooling stacks of both converters were modified and provided with easy-to-maintain SMS group Baumco adjustable skirts. These are lowered hydraulically onto the converter mouth during the blowing phase and they enable the primary gases to be extracted efficiently under suppressed combustion. In addition, diffuse dust emissions are substantially reduced. Gas recovery is used in the best possible way by generating CO gas under suppressed combustion.
The SMS group scope of supplies 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 incorporate the adjustable skirts with labyrinth seal and the modernization of the inlet section leading into the scrubbing tower for further flue gas cooling.
The steam produced in the cooling stacks is used as process steam in the entire integrated iron and steel plant. The complete energy recovery from the two cooling stacks is thus performed with extremely high energy efficiency.
“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.
SSAB is Scandinavia's largest producer of flat steels.