SMS Siemag revamps SSAB converter shop and meets stringent environmental standards
SSAB Luleå, Sweden, has awarded SMS Siemag (www.sms-siemag.com) Germany, the contract for the revamp of the converter shop and related environmental technology. The objective of SSAB is to extend the output of the two converters and to reach the stipulated high environmental standards.
SMS Siemag will supply lamella suspension systems and the converter tilt drive systems for both converters. The two-motor tilt drive systems are easily accessible and very maintenance-friendly. The scope of supply equally includes the converter trunnion bearings, the increase in height of the existing trunnion pedestals as well as installation of the vessels and trunnion rings.
Thanks to the design concept developed by SMS Siemag, the new converter vessels have a clearly greater volume. With an unchanged quantity of material charged, of up to 130 tons, it is possible to increase the internal volume of the converter by 10 percent. The additional capacity facilitates more environmentally friendly process control and efficient energy recovery.
“I am looking forward to benefitting from this new technology and to breathing new life into our steelmaking plant”, says Kurt Lindqvist, Project Manager at the SSAB Luleå Converter Shop.
Improved utilization of the existing installation space has made it possible to achieve this increase in capacity. This is possible due to the lamella converter suspension system developed and patented by SMS Siemag. It is a maintenance-free converter suspension system designed for arranging the converter vessel in the trunnion ring without restraint.
By using the lamella converter suspension system, along with the design of an enlarged clearance and the use of high-grade heat-resistant fine-grained structural steels, the converters are well prepared for the thermal loads. This is achieved without any additional cooling fluids; sufficient cooling is ensured merely by the natural thermal conditions.
The SMS Siemag Ecoplants solution comprises the revamp of the primary gas cooling system of the BOF steelmaking plant. To this end, the cooling stacks of both converters are modified in a first phase and provided with easy-to-maintain SMS Siemag 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 Siemag scope of supply and services includes 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, making the complete energy recovery from the two cooling stacks extremely energy efficient.
“With the new SMS Siemag environmental control technology, we continue to be trailblazers in environmental protection. The Swedish government has imposed these more stringent requirements on the whole country and we readily meet them”, says Gerhard Böttcher, Project Manager, SSAB Luleå Converter Shop.
The complete conversion will be done during a scheduled shutdown in summer 2015.
SSAB is Scandinavia's largest producer of flat steels.
SMS Siemag AG and SMS Meer GmbH are both companies of SMS group which, under the roof of SMS Holding GmbH, consists of a group of companies internationally active in plant construction and mechanical engineering for the steel and nonferrous metals industry.