In phase 1, SMS group had installed a new, more efficient filter system and replaced the canopy hood of the electric arc furnace with an SMS frustum hood. In this connection, the secondary gas line was also renewed, and an axial cyclone was installed as spark separator upstream of the new jet pulse filter. In phase 2, the primary gas line for direct exhausting of the hot fumes from the 60-ton electric arc furnace was renewed.
The scope of supply of phase 2 consisted of a water-cooled fumes section, a gas cooler with bypass, and a radial-flow fan for pressure boosting. The hot fumes forming during the melting process are used to dry and preheat the scrap and adhering ice is removed this way. The installation of a cooler with bypass maintains the entry temperature at the scrap pre-dryer at maximum 300 °C, which prevents the formation of contaminants during scrap drying. The water-cooled components were optimized with regard to pressure losses and already prepared for the future use of an energy recovery system.
The modernization of the fumes treatment system yields quite a number of advantages. The new technology achieves a rise in fumes volume by 66 percent without increasing the energy consumption in comparison with the old system. The SMS frustum hood allows clearly more effective capturing and exhausting of the fumes during furnace charging and tapping. The dust content at the stack outlet is 50 percent below the requested value. The drying of the scrap guarantees safe operation of the furnace, and in the future it will be possible to recover energy by way of the extraction of hot water.