Thermal analysis of sponge iron preheating using waste energy of EAF

Energy consumption and production capacity are two major concerns in the steel making industries which are using electric arc furnace (EAF). To improve the performance of EAF, a new initiative technique has been introduced in which sponge iron particles are preheated before entering the furnace. A heat exchanger is used to transfer waste energy from EAF flue gas to a neutral gas like nitrogen, which in turn preheats the sponge iron particles in the fixed bed. The method has several desirable advantages including electric energy saving, increasing the productivity and reduction in electrode and refractory consumption. In order to estimate the extent of energy saving and productivity increase, the preheating process was simulated in the bed. The thermal characteristics of the fixed bed were predicted by a numerical solution of differential equations for granular sponge iron and heating gas. The temperature of sponge iron particles and heating gas were also predicted in different layers of the bed and at different times. Based on the simulation results it is found that the energy consumption in the EAF can be reduced up to 14% and productivity can be increased up to 13%.