A new dedusting system is said to be significantly helping to improve environmental protection following its installation on a circular cooler with an integrated heat recovery system at sinter plant 3 of ROGESA Roheisengesellschaft Saar mbH, a joint subsidiary of Dillinger and Saarstahl. The environmental project represents an investment of EUR 28 million.

According to Dillinger, the heat recovery generates an additional energy benefit of 82,000 MWh, which equals a reduction of carbon emissions of approx. 25kt/yr. The circular cooler dedusting itself significantly reduces dust emissions.

While the use of hydrogen is currently the central topic of 'green' steel production, much more time will be needed before sufficient hydrogen is available in industrially usable quantities. Until then, Dillinger and Saarstahl are optimizing their existing plants in terms of sustainability and climate protection on the way to producing carbon-neutral steel. The two companies have initiated environmental investments amounting to EUR 70 million over the last two years .

"With the new circular cooler dedusting system, we have successfully created a win-win situation for the environment and efficiency. The energy gained from heat extraction reduces carbon emissions and generates more electricity that does not need to be purchased. At the same time, dust emissions are being further reduced and recycled: we are thus continuing our efforts to ensure that the most sustainable steel companies are located at the Saar river,” said Martin Baues, chief technical officer of Dillinger and Saarstahl, who gives the new circular cooler dedusting system high marks.

A large-area cover on the circular cooler ensures that dust emissions generated as the sinter cools are extracted in a controlled manner and fed to a filtering system. The resulting exhaust air, with temperatures ranging from about 350 to 400 deg C, is also sucked in and fed to an additional integrated heat extraction system. The heat from the air is transferred there to a hot water circuit resulting in water heated to a temperature of around 190 deg C which is then used under high pressure to preheat the condensate circuit in the blast furnace gas power plant and to preheat the feed water for the companies at the site. The separated dust particles from the filter system are returned to the production cycle and recycled in the sinter plant. In the interests of efficient use of resources, care is taken to ensure that as much raw material and energy as possible are returned to the production cycle.