Numerical investigation on hot metal flow in blast furnace hearth through CFD

Abstract

The behavior of hot metal flow in the hearth of a blast furnace is always considered as one of the key factors for determining blast furnace campaign life. To provide a useful insight into the hearth of No. 2 blast furnace at China Steel Corporation (CSC), a numerical model has been developed to analyze the flow and heat transfer under various cooling and operational conditions. The model solves three-dimensional Navier-Stoke equations with conjugate heat transfer and Darcy's law for hot metal flowing through the deadman with porous structure by computational fluid dynamics (CFD). The calculated results indicate that the circulatory hot metal is enhanced when the deadman becomes sitting with gutter coke-free space. As a result, the temperature at the hearth corner increases. This suggests the existence of gutter coke-free space may cause elephant foot type erosion. With drainage of hot metal, the heat flux of taphole significantly increases. For the sake of safety, it may be needed to individually monitor the cooling water temperature flowing through the copper staves, as well as to install thermocouples around the tapholes. The prediction shows that the heat flux of the hearth is insensitive to the temperature of cooling water before the refractories are eroded. It implies that the performance of the water chiller may be limited in the beginning of the blast furnace campaign. © 2008 ISIJ.