The post-combustion chamber of steelmaking plants: Role of ambient air in reactant exhaust fumes

摘要

The overall performance of the post-combustion chamber of steelmaking plants is controlled by the size of the gap that allows for the ambient air to merge with the hot gas stream exiting the fourth hole of an electric arc furnace. The impact of the opening coefficient (ratio between the gap area and the total area) on the post-combustion chamber performance has been investigated by a comprehensive 3D, steady, CFD simulation comprising radiative heat exchanges and detailed chemical reactions. It is found that no unique value of the opening coefficient is capable of optimizing all the relevant quantities of the evacuation process of exhaust fumes. A value of the opening coefficient comprised in the range 0.40-0.52 appears advisable in the investigated model geometry. It is shown that the accurate knowledge of some boundary conditions at the gap does not grossly modify the above serviceable range. Inefficiencies of the sample post-combustion chamber are highlighted and fan power savings are advised.