Assessment of Waste Heat Recovery in the Steel Industry

Abstract

A considerable portion of the energy consumed in the steel industry is rejected as waste heat from the electric arc furnace. Capturing this energy impacts the efficiency of production significantly by reducing operating costs and increasing the plant’s productivity. It also presents great opportunities to increase the industry’s competitiveness and sustainable operation through a reduction in emissions. This work presents an assessment of steel manufacturing, and demonstrates the potential of thermal energy storage systems in recovering heat from the high-temperature exhaust fumes of the electric arc furnace. Our investigation entails mapping the material and energy requirements of one of two-phase of the current steel production method, i.e. natural gas reforming for syngas production, direct reduction of the iron ore, and secondary refining to obtain the steel in the electric arc furnace. Analysis of an obtained electric arc furnace off-gas temperature and flow rate profiles are then used as a basis in the development of a waste heat recovery model. Simulation results from the waste heat recovery module reveal that in a period of 4 days, an output power of 2108 kW per tap-to-tap cycle can be achieved from a continuous charge electric arc furnace. This can be harnessed and used either internally or externally to the steel manufacturing process. This is inevitably coupled with a reduction in CO2 emissions, which works to actively address climate change.