ThyssenKrupp Steel Europe to modernize converter plant and waste heat boiler
The modernization is a logistical tour de force: While production in converter 2 continues, around 1,000 specialists working on two job sites will ensure a smooth rebuild.
Since 1969 the two converters in Ox 1 have been the basis for steel production in Duisburg-Bruckhausen. In the refractory-lined steel vessels pig iron is converted into crude steel with the addition of scrap and slag formers. Oxygen is blown onto the heat to remove impurities such as carbon, silicon, manganese and phosphorus. The steel is then tapped at a temperature of 1,700°C. 44 years of continuous operation, around 211,000 heats and an output of approx. 80 million metric tons of steel have left their marks on converter 1. Now it is to be replaced.
For Chris Lindner, melt shop superintendent with ThyssenKrupp Steel Europe, the project is a technical and organizational challenge: "We are removing the old equipment and installing the new while the neighboring converter operates as normal. We are working on two levels: on the converter itself and at the same time on the waste-heat boiler system, which extends to a height of almost 70 meters above the converter opening."
The new converter vessel is one of the biggest of its kind worldwide, with a height of eleven meters, a diameter of eleven meters and a weight of roughly 500 tons. The fine-grain structural steel for the converter was produced at ThyssenKrupp Steel Europe's steelmaking plant in Duisburg-Beeckerwerth and rolled in Duisburg-Hüttenheim. Thanks to a new method of construction the new converter vessel will be significantly wider. With an unchanged charge weight of up to 400 tons, the inner volume of the converter has been increased from 218 to 270 cubic meters. The additional capacity will allow more environmentally friendly operation and more efficient energy recovery.
The logistical effort involved in replacing the converter is huge. The vessel and trunnion ring were made by equipment manufacturer SMS Siemag in Italy. From there the converter was transported in seven pieces by ship to Walsum port and by road to the Bruckhausen steel plant in April this year.
ThyssenKrupp specialists are maneuvering the massive elements across the shop floor to the pre-erection area in the Bruckhausen melt shop using a six axle platform car.
There the pieces are being joined together, moved to their final destination by shop crane and installed. Up to 1,000 workers are involved in dismantling the old converter and installing the new one and the waste-heat boiler.
Special crane to move boiler segments
Directly above the work on the converter floor, four segments of the waste-heat boiler system are also being replaced. The almost 50 meter long system of water pipes cools the converter gas from 2,000°C down to roughly 500°C. The steam produced in the process flows into the mill's steam network and is supplied to other consumers in the mill. The cooled converter gas is cleaned and is used for example as fuel for the reheating furnaces in the hot strip mills.
The new boiler segments were made by the Essen-based equipment manufacturer Oschatz. They are almost four meters in diameter. The heaviest element weighs 50 tons. As the waste-heat boiler has to be positioned roughly 20 meters above the converter opening, three of the four boiler segments are being lifted into the converter shop on the hook of a special crawler-mounted crane with a 140 meter boom positioned on the south side of the Duisburg-Bruckhausen melt shop.
45 days have been planned for the whole operation. The first heat in the new converter is scheduled to be produced in mid-September.
Source – Strategic Research Institute