Heat transfer analysis and estimation of refractory wear in an iron blast furnace hearth using finite element method

Abstract

The wear of hearth refractory by hot metal penetration and mechanical erosion is the limiting factor in the life of a blast furnace and their control and minimisation result in a direct benefit in an extended campaign. At the same time, it is difficult to directly measure the amount and location of hearth erosion during any campaign. Heat transfer mathematical model is an appropriate tool to quantify the amount of erosion based on the prediction of temperature profile particularly 1150°C freeze line isotherm in the hearth. In the present investigation, an axisymmetric conductive heat transfer model based on finite element method has been formulated and computer software is developed. Using the model and the computer code, temperature profile is predicted in the hearth zone of two different designs of industrial blast furnaces and maximum (worst) hearth wear has been estimated. The erosion pattern is calculated on the basis of worst-case location of 1150°C isotherm that can occur during the furnace campaign. Effects of hot metal temperature, cooling conditions and coke-bed states (floating and sitting) on temperature profile and refractory wear are also investigated. © 2005 ISIJ.