Effect of Coal-Dust Fuel and Compensating Measures on Blast Furnace Charge Softening Zone Gas Permeability

Abstract

The effect of coal-dust fuel and the main compensating measures on the change in gas pressure drop in a blast furnace charge softening zone (Δp_sz ) is estimated by calculation. The change in gas permeability in the charge softening zone is evaluated using a mathematical model based on contemporary concepts of the softening zone structure.

Calculations show that an increase in coal-dust fuel consumption from 100 to 160 kg/ton of pig iron is accompanied by an increase in Δp_sz . In order to reduce the Δp_sz with injection of this fuel, compensating measures are used in the mathematical model. An increase in iron content in the charge from 56 to 60% provides a reduction in the Δp_sz by 1.1–1.5%. An increase in coke strength from 40 to 50% makes it possible to reduce Δp_sz by 20–25%. Use of iron-ore materials with a lower softening temperature range makes it possible to reduce Δp_sz by 25%. In addition, formation of developed axial gas flow makes it possible to reduce Δp_sz by a factor of 2.6.