Effect of the Change in Parameters on the Longitudinal Distributions of Process Variables, the Production Rate and the Carbon Ratio in Blast Furnace

Abstract

Rate constants of indirect reduction of iron ores by CO and of solution loss, heat transfer coefficient between gas and solid particles, over-all heat transfer coefficient for heat loss from furnace wall and fractional prereduction of iron ores are considered as the parameters in this work. On the basis of the mathematical model of blast furnace process reported previously, the variations of the production rate of pig iron, the carbon ratio and the longitudinal distributions of process variables caused by the changes of the parameters mentioned above are calculated with the aid of a digital computer (HITAC 5020 E).
According to the calculated results, the reduction of iron ores proceeded rapidly in a lower part of furnace when the value of activation energy relating to the rate constant of indirect reduction was large, and the production rate of pig iron, W_p, increased and the carbon ratio, C_r, decreased with the increase in this activation energy.
Both W_p and C_r were not affected so much by the rate constant of solution loss, but the longitudinal distributions of process variables in a lower part of furnace were influenced considerably by the change of this constant.
The value of heat transfer coefficient between gas and solid particles, h_p, influenced remarkably on the temperature distributions and the rates of reduction and melting of iron ores. And, W_p increased and Cr decreased with the increase in the value of h_p.
It was found that the linear variations of W_p and C_r were caused by the change in the value of over-all heat transfer coefficient for heat loss from furnace wall, and that W_p proliferated and C_r decreased exceedingly with the increase in fractional prereduction of iron ores.