Numerical investigation on effects of cooling water temperature and deadman status on thermal flow in the hearth of blast furnace during tapping shutdown

Abstract

In this study, we aim to investigate the effects of cooling water temperature and deadman status on thermal flow in the hearth of a blast furnace (BF) during tapping shutdown according to the geometric model and boundary conditions given from the BF No.2 that has three asymmetrical tapholes in the hearth of BF at Dragon Steel, Taiwan. The mathematical formula includes the assumption of incompressible fluid, transient turbulent momentum conservation with standard k-εmodel, non-Darcy porous media, Boussinesq approximation, transient turbulent energy conservation, and conjugate heat transfer between solid and fluid. It is simulated that the tapping shutdown is induced by No. 2 taphole from tapping to shutdown while No. 1 and No.3 tapholes are always closed. As shown in the numerical results, the wall heat flux near the taphole area increased significantly with the decrease of cooling water temperature. When the cooling water temperature was decreased from 35 °C to 10 °C, the wall heat flux near No.2, No.1, and No.3 tapholes increases by 11.5%, 30.4%, and 30.4% respectively. During tapping shutdown for one hour, the wall heat fluxes near the taphole area for gutter deadman and floating deadman in the blast furnace hearth were increased by 0.94% and 1.46%, respectively. These results would be useful to optimize operating conditions of blast furnace hearth, thus reducing the ironmaking cost.