Abstract
An investigation was made on the oxygen enrichment to blowing gas up to 40% by using an experimental blast furnace.The oxygen ratio in this experiment was increased under the condition of constant bosh gas volume per unit time.Coke rate was slightly decreased with inc: easing the oxygen content up to 25%. In further increase of oxygen content beyond 25%, the coke rate was increased to about 2.5kg/t HNI for each 1% of oxygen enrichment, but increase of prcductivity of iron of 5% was obtained.
Gas temperature distribution was measured to make clear the heat exchange phenomena between gases and solids, and the temperature of solids was estimated by simulation calculation. From this result, it was deduced that the oxygen enrichment blowing operation was limited due to the shortening of the length of thermal reserve zone with increase of oxygen enrichment.
The main reason for the increase of the coke rate could be explained by calculated results of decreasing indirect reduction rate of ores which was influenced by the above temperature distribution change.
This became another commercial limit of oxygen enrichment blowing.
