WCA March 2016

Technology news

Energy-efficient Linde ❍ Rebox DST at Dongbei Special Steel Group at Salina, China

Other important advantages with Rebox DST include a much higher uniformity of the material properties after the treatment, for example tensile strength variations of less than ±10N/ mm 2 . The temperature uniformity in the process is excellent. Also the scale losses are substantially reduced, typically by one per cent point. The existing Rebox DST installations treat wires from 4.5 to 20mm with 1,100mm coil diameter. The fuels used include LPG, natural gas, and generator gas (gasified coal). The currently largest installation, in Korea, can process up to 72.5 tonnes per hour. At Dongbei Special Steel Group in China, a new state-of-the-art Rebox DST annealing furnace was brought

into operation in 2010. The flameless combustion uses a low calorific fuel with an energy content of 1,500 kcal/ Nm 3 . Periodically, blast furnace top gas (BFG) with a CV at 835 kcal/Nm 3 has been successfully used in this installation. Recently, Yongxing Special Stainless Steel, also of China, awarded Linde a turnkey contract for a 60 tonnes per hour Rebox DST installation, to be commissioned by the end of 2016. Rebox DST is an example of how Linde helps its customers to increase production efficiency, save fuel consumption and decrease emissions. The Linde Group – Germany Website : www.linde.com

REBOX DST is Linde’s energy-efficient process for inline continuous treatment of stainless steel wire. In a conventional operation line, after the finishing block of the rolling, the coiled wire is cooled down to ambient temperature and then heated up again in batch annealing furnaces. Using the Rebox DST (Direct Solution Treatment) process, the rolled wire is instead fed directly into a continuous operating furnace fired with flameless oxyfuel. With Rebox DST the heating takes place from 850 to 900°C instead of from ambient temperature and with an energy efficiency that is more than twice that of batch annealing. The time required for the operation is reduced by more than 90 per cent.

Graphics bigstockphoto.com Artist Olechowski

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