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Company News, 2008-03-19, 11:00 AM

Fifth furnace campaign can begin:Blast furnace 1 in Duisburg-Schwelgern to restart operation in April after modernization

After a record downtime of only 70 days, blast furnace Schwelgern 1 of ThyssenKrupp Steel in Duisburg is expected to begin its fifth campaign (production period between major overhauls) at the beginning of April. Built in 1973, the unit was shut down at the end of January after a campaign lasting approximately 12 years.

The unit is now being completely modernized. The inside of the blast furnace is being relined with refractory material – 5,500 tons of advanced material will be used for this alone. A specialized contractor is carrying out the bricklaying work from five platforms arranged at different heights – a particularly fast and effective method of operation. In addition, the furnace cooling system is being upgraded. 1,800 out of a total of 2,100 cooling plates are being replaced, and six rows of cooling plates will replace one row of staves to intensify cooling in the bosh.

In the casthouses, the complete runner system and refractory lining are being replaced. The taphole equipment is also being overhauled. The refectory lining of the hot blast stoves is being refurbished, the screens, controls and extraction lines in the stockhouse are being modernized. Further repairs and renewals are being carried out on the coal injection system, gas cleaning system, emergency water supply, re-cooling system, slag granulation system as well as the expansion turbine, clarification plant and sludge drying system.

An approximately 300-strong team from ThyssenKrupp Steel is handling this gigantic modernization project with the help of around 100 national and international contractors – a significant proportion of the work is being carried out by companies from other segments of the ThyssenKrupp Group. Around 1,100 external workers are busy on the site each day. The relining work is being coordinated from a specially built 10,000 square meter container village. The mobile offices are the nerve center of the planning effort, but there is also enough space for fabrication and storage.

The project was planned down to the last detail over a one and a half year period in order to keep downtime as short as possible. The project team drew on experience from previous relines to optimize work processes and carry out certain jobs – for example on the auxiliary units – before the furnace was shut down. The team is optimistic that it will complete the work within 70 days. By way of comparison, the last reline in 1996 took over 80. Every day counts in a major modernization project like this because downtime means loss of production. The reline of blast furnace 1 is part of a general program to overhaul ThyssenKrupp Steel’s ironmaking operations, and precise coordination is essential to minimize production losses. The fifth campaign of Schwelgern 1, due to begin in April, will be the longest so far: the project team expects it to last more than 12 years.

Overall, the upgrade represents an investment of around 150 million euros, and over a tenth of the cost is for additional pollution control equipment. To further improve the environmental situation, a new filter unit was built to collect casthouse and stockhouse dust in 2004. The new unit was part of an extensive dust reduction program which ThyssenKrupp Stahl agreed in April 2001 with the North Rhine Westphalia environment ministry. As part of the 2008 reline, the stockhouse dust extraction system is being renewed, the hoods on the slag granulation unit are being replaced and the silencers on the energy-recovery expansion turbine are being overhauled. Also, the noise barriers in the clarification plant and sludge drying system are being renewed to minimize noise emissions. Incidentally, when the furnace was built at the beginning of the 1970s the casthouse and stockhouse dust collection systems, gas cleaning, water treatment and noise protection facilities were regarded as the latest in international blast furnace technology.

Since blast furnace Schwelgern 1 began operation on February 13, 1973, new technical solutions have been found and implemented which are today international standard. The then August-Thyssen-Hütte (ATH) in Duisburg celebrated the new blast furnace as the largest in the Western world. It was a project of gigantic dimensions: on 17.5 hectares of land, 210,000 cubic meters of earth were excavated for the 110 meter tall furnace with a hearth diameter of 14 meters and a furnace capacity of 4,200 cubic meters. 70,000 cubic meters of concrete and 38,000 tons of steel were needed for the foundations, platforms and buildings. By comparison, the same amount of steel could be used to build nearly four bridges over the Rhine.

After three and a half decades of production, blast furnace Schwelgern 1 will produce its one hundred millionth ton of pig iron at the beginning of May 2008 – a benchmark which only few blast furnaces worldwide have achieved. Each day, the furnace, which was built for 175 million euros, gets through around 20 freight trains each containing 20 cars of ore, sinter, coke and coal. It produces 10,000 tons of pig iron a day, twice as much as the previous best blast furnace. Every second, two blowers press around 100 cubic meters of blast air through 40 tuyeres into the furnace. Almost 100 water pumps are installed for cooling, gas cleaning and converting blast furnace slag into granulate. The water is treated and completely recycled.

Today, blast furnace Schwelgern 1 provides 550 jobs for employees of ThyssenKrupp Steel AG, plus several times that number at outside contractors in the region.

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