Influence of ore/coke distribution on descending and melting behavior of burden in blast furnace.

Abstract

The influence of ore/coke distribution on the descending and melting behaviors of burden was analyzed by using a three-dimensional semicircular warm model of the blast furnace under conditions set as similar as possible to the physical phenomena in the furnace. It is confirmed that the ore/coke largely influences the descending velocity of burden and gas flow. It is estimated that an increase of +0.1 in the heat-flow ratio in the wall region of bosh results in a decrease of about 5°C in the temperature near the reaceway and in the wall temperature of bosh. It corresponds about 80°C in the value converted into that of the actual blast furnace based on the Stanton number. In Tobata No. 1 blast furnace of Nippon Steel Corp., it is verified that an increase of the ore/coke in wall region results in an increase of the descending velocity in wall region, and the ore/coke and the descending velocity are ones of the main factors which decrease the temperature in the lower part of the furnace. At the all coke operation, as the wall temperature in the lower part of the furnace tends to decrease, the ore/coke near the wall should preferably be decreased by the charging of ore closer to the furnace center. At the operation by injecting a large quantity of pulverized coal, as the melting capacity near the wall is large, the ore/coke in the wall region should preferably be increased and the ore/coke in the center region should preferably be decreased by the charging of ore farther from the furnace center.