Simulation and Design for Waste Heat Recovery in Electric Arc Furnace Metal Pools

A significant amount of waste heat is generated in the metal pools during the production of high carbon ferrochrome in electric arc furnaces. This waste heat manifests itself in the form of heat emitted to the atmosphere from the metal pools and the temperature of the flue gases. Although there are many studies on waste heat recovery from flue gases, there is limited research on waste heat recovery in metal pools. In this study, the recovery of waste heat generated in metal pools in ferrochrome production at Eti Krom INC., the world's largest producer of hard piece chromium, was investigated. The product produced during ferrochrome production is left to cool in metal pools. The initial temperature of ferrochrome metal, which starts to cool in the pools, is between 700-800 °C. In this context, the proposed system consists of heating the water circulating in the pipe from 15-20 °C to 85-90 °C by utilising the waste heat with the heat exchanger system mounted under the metal pools. Different numerical simulations have shown that the designed system can successfully heat water to 85-95 °C by utilising waste heat. Economic analyses were made for the designed system to be obtained by energy recovery from waste heat. As a result, it was determined that the energy required to raise 10 m3 of water from 15 °C to 85 °C with this system is 813 kWh energy and this energy is equivalent to 195 kg coal or 91 m3 natural gas consumption. In addition, the recovery of waste heat in the metal pools through this system significantly reduces waste heat and carbon emissions in the atmosphere by reducing fossil fuel consumption.