Dripping Liquid Metal Flow in the Lower Part of a Blast Furnace

Abstract

Numerical simulation of blast furnace phenomena has significantly contributed to the better understanding of iron making process. Recent interest on minimizing fuel consumption and reducing environmental problems have also benefitted from the development of comprehensive simulation models based on physical principles. One of the under-developing fields, however, is related with the internal phenomena in the lower part of the blast furnace under the cohesive zone, where the liquid phase of metal and slag flows downward over the bed of solid coke particles. Hot flow of sluggish liquid phase is further complicated by the chemical reactions including the transfer of silica into the silicon in the hot metal. Silica enters the furnace as a constituent of coke ash and ferrous gangue, and exits as either molten silica in slag or dissolved Si in the hot metal. Silica reduction is an endothermic reaction, which would alter the heat transfer in the lower furnace, thus affecting the hot metal temperature.Effective flow in the dripping zone is important for stable operation of the blast furnace with high productivity of iron. Study of the liquid flow behavior and secondary reactions in a packed bed allows to investigate the effect of various operational changes in the dripping zone. In this research, a systematic numerical approach for the liquid flow is presented where the flow behavior is solved along with heat transfer associated with physic-chemical reactions among representative components.

Analysis of the Rheological Behaviour of Selected Semi-Solid Slag Systems in Blast Furnace Flow Conditions

“…These changes result from the limitation of measuring/testing capabilities of the dynamic viscosity coefficient for the system tested and the physical properties of the liquid tested (density, dynamic viscosity), as well as its structure and behaviour under the influence of shear stress. Table 1 compares the rotational speeds of the spindle and the corresponding linear velocities of the gas flowing through the coke bed (for the 0,4 and 25m/s -appropriately column Table 1) and the assumed values of the linear velocity of dripping products (at the range 0,04m/scolumn with N o 2) in Table 1) of processes in the dripping zone [14][15][16].…”

“…However, cold models are often created. These aim to describe the flow of pig iron and slag in the coke bed counterflow to the reducing gas [14][15][16].…”

“…Many authors dealing with the modelling of effects in the dripping zone identify [14][15] the area of liquid products and their dripping as shown in Figure 1a and 1b. Fig.…”

“…1. Blast furnace dripping and cohesive zones [14,15] Liquid slag systems in some areas of the blast furnace are not fully homogeneous. This results, among others, from their thermodynamic conditions, e.g.…”

“…It directly influences the kinetics of reactions occurring between the liquid metal and the slag, as well as the effect of the flow of these phases in metallurgical units. The dynamic viscosity of the liquid slag and iron is amongst the basic indicators participating in the analysis of permeability of the coke bed in the blast furnace and its static and dynamic holdup [14][15][16].…”