Products and solutions, 2003-02-12, 01:00 AM
30th anniversary of Duisburg-Schwelgern blast furnace - From Black Giant to high-tech colossus
On February 13, 1973, the biggest blast furnace in the western world was blown in by August-Thyssen-Hütte (ATH) in Duisburg-Schwelgern. It was a gigantic project: Over an area of 17.5 hectares, 210,000 cubic meters of earth were excavated for the 110 meter tall furnace with a hearth diameter of 14 meters and a capacity of 4,200 cubic meters. Approximately 70,000 cubic meters of concrete and 38,000 tons of steel were needed for foundations, platforms and buildings. The same amount of steel would be enough to build almost four bridges over the Rhine.
In three decades, Schwelgern 1 blast furnace has produced more than 83 million tons of hot metal. Translated into medium-gauge sheet that corresponds to an area of 2,300 square kilometers or ten times the area of the city of Duisburg.
Each day, Schwelgern 1 blast furnace gets through twenty 20-car freight trains of ore, sinter, coke and coal. Each day it produces 10,000 tons of hot metal, twice as much as the previous biggest blast furnace at the time. The steel giant was built in response to growing demand for steel at the end of the 1960s. Replacing some of the nine blast furnaces operated by the company in Hamborn, it was sited at Schwelgern on the Rhine because of its better transport links for raw materials supplies. The startup of Schwelgern 1 blast furnace transported the August-Thyssen-Hütte mill into a new dimension. Two hot blast blowers pump around 100 cubic meters of air per second into the furnace through 40 tuyeres. Close to 100 water pumps are installed for cooling, gas cleaning and converting blast furnace slag into granulate. The water is treated and recycled in closed circuits.
Of the total of DM350 million (175 million euros) invested by ATH (today`s ThyssenKrupp Stahl) in the facility 30 years ago, 15 percent was spent on pollution control. The environmental standards applied by ATH and the health and safety authorities in building this colossus at Schwelgern dock were stricter than any applied before; exemplary solutions were used for stock-house and cast-house dust removal, gas cleaning, water treatment and noise control.
However, soon after the new blast furnace was blown in there were increasing protests from nearby residents about the noise. Four weeks after startup the blast furnace was faced by the threat of closure. The public safety authorities complained that important conditions had not been met. The company appealed against the closure notice imposed by the authorities and the case ended in a settlement under which the blast furnace was allowed to continue operation but August-Thyssen-Hütte had to reduce the noise levels substantially within six weeks. The myth of the Black Giant was born. A year later, following extensive measures, the noise levels had been reduced to a whisper and dust emissions had also been significantly cut.
These teething troubles are almost forgotten in Duisburg today. The blast furnace, together with a second plant built in 1993, is now part of the Marxloh and Walsum landscape and is still one of the most efficient in the world. In 1996 it was completely modernized - the technical term is relining. After a ten-year campaign, the steel giant took an 85-day break during which much of its equipment, from hot blast stoves and charging equipment to cooling systems and pipes, was replaced. Where previously temperatures of up to 2,000 degrees Celsius had prevailed, bricklayers were now at work replacing the furnace`s worn refractory lining. In all, 450,000 bricks were replaced. The central control station was also modernized. Both blast furnaces in Schwelgern are operated from a central control pulpit where all furnace operations are monitored and controlled.
In 30 years, ThyssenKrupp Stahl AG has spent millions on improving pollution control at Schwelgern 1 alone. One focus of investment has been on dust removal equipment for the coke unloading station and the stock bins, thanks to which dust emissions have been significantly reduced. The coke conveyor has also been enclosed to avoid dust emissions. In addition, filter elements have been replaced in the cast-house and stockhouse dust collection systems. Opportunities for reducing energy consumption have been opened up by sophisticated heat recovery systems. For example, the fuel for the hot blast stoves is preheated with the waste heat from a sinter cooler. Incidentally, since 1973 ThyssenKrupp Stahl has used the residual heat contained in the stove off-gas to heat around 5,000 homes via a district heating network.
To further improve the environmental situation there are plans to build a new filter unit to collect dust from the cast house and burden preparation area. This unit is part of a comprehensive dust reduction program agreed by ThyssenKrupp Stahl in April 2001 with the North Rhine-Westphalia environment ministry and will go into operation next year. Schwelgern 1 blast furnace provides around 560 jobs for employees of ThyssenKrupp Stahl AG as well as another 130 at local service contractors.
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Fax: +49 203 / 52 - 2 57 07