Improved CFD Model to Predict Flow and Temperature Distributions in a Blast Furnace Hearth

Abstract

The campaign life of a blast furnace is limited by the erosion of hearth refractories. Flow and temperature distributions of the liquid iron have a significant influence on the erosion mechanism. In this work, an improved three-dimensional computational fluid dynamics model is developed to simulate the flow and heat transfer phenomena in the hearth of BlueScope's Port Kembla No. 5 Blast Furnace. Model improvements feature more justified input parameters in turbulence modeling, buoyancy modeling, wall boundary conditions, material properties, and modeling of the solidification of iron. The model is validated by comparing the calculated temperatures with the thermocouple data available, where agreements are established within ±3 pct. The flow distribution in the hearth is discussed for intact and eroded hearth profiles, for sitting and floating coke bed states. It is shown that natural convection affects the flow in several ways: for example, the formation of (a) stagnant zones preventing hearth bottom from eroding or (b) the downward jetting of molten liquid promoting side wall erosion, or (c) at times, a vortex-like peripheral flow, promoting the ''elephant foot'' type erosion. A significant influence of coke bed permeability on the macroscopic flow pattern and the refractory temperature is observed.

Review on Modeling and Simulation of Blast Furnace

“…This has mainly been done based on continuum models. [19,21,23,26,27,[83][84][85][86][87][88][89][90] Generally, these models consider a single-phase flow, treat the coke bed as porous media, neglect movements of coke and liquid interface, and regard the flow and heat transfer as under a steady state. Also, Finite Volume Method (FVM), which is widely used in CFD computation, was Figure 2.…”

“…Comparison of the calculated and measured temperatures for Cases A-D): cross dots, measured temperature; dashed lines, calculated temperature for the coke bed with the porosity of 0.35 and the particle size of 30 mm; and solid lines, calculated temperature for the bed coke with the porosity of 0.30 and the particle size of 12 mm. [27] Figure 4. It reveals that the floating state of the coke bed becomes more obvious in the hearth with increasing gas velocities.…”

“…Ueda et al [12] in 2010 and Ariyama et al [13] in 2014 further discussed the new efforts reported for the discrete simulation of BF, respectively. However, the previous reviews did not pay much attention to the modeling efforts dedicated to hearth [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and raceway, [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] of which the performance plays a critical role in determining BF campaign life, as well as operation and maintenance costs. Also, considerable model developments based on either discrete or continuum approach have been made recently.…”

Microstructure and Phase of Carbon Brick and Protective Layer of a 2800 m³ Industrial Blast Furnace Hearth

“…1) The performances of carbon brick in blast furnace hearth have been widely studied. [1][2][3][4][5][6][7][8][9][10][11][12] These studies indicated that the peripheral flow of molten iron, dissolution of molten iron, attack of zinc and alkalis, thermal stress and fluid induced shear stress are the reasons for the corrosion of carbon brick. With the deterioration of raw materials and fuels, the blast furnace is facing great challenges.…”

Numerical Analysis of Titanium Compounds in Blast Furnace Hearth During Titania Addition

“…Successful formation of a protection layer near the eroded regions of the hearth refractory lining depends greatly on the flow and heat transfer of the liquid iron and hence furnace operating conditions. The flow and heat transfer in the hearth is quite complex itself . Further, the dosage of titania required to form the protection layer should be minimized as excess amounts cause adverse effects on the post‐processing of liquid iron.…”