Optimization of pulverized coal injection into blast furnace

Pulverized coal injection is one of the most effective measures to reduce coke ratio in blast furnace production. To obtain a higher coal/coke replacement ratio and reduce the cost of blast furnace production, it is necessary to select and match the coal injection types reasonably from a varieties range of coal. 12 types of coal provided by foreign steel plant were selected as experimental materials, and their basic property and process property which played a key role of pulverized coal injection in blast furnace were investigated systematically. Furthermore, comprehensive performance of different pulverized coal was studied based on the basic property result of test, and provided a guidance for optimal selection of pulverized coal injection into blast furnace. The results are shown that among the 12 kinds of coal powders, No.4 is high metamorphic anthracite, No.6, No.7 and No.12 are high metamorphic meager-lean coal, No.5, No.10 and No.11 are low metamorphic meager-lean coal, and No.1, No.2, No.3, No.8 and No.9 are low metamorphic bituminous coal. Compared with the pulverized coal injected into blast furnace in China, the 12 kinds of pulverized coal provided by foreign steel plant have lower ash and sulfur content, it is beneficial to reduce the amount of slag and sulfur load. Meanwhile, the pulverized coal has good jet performance, high fluidity and higher ash fusion temperature. Low metamorphic bituminous coal is explosive and cannot be used as blast furnace coal injection alone. The grindability and combustion performance of different coal powders vary greatly, which is the key to limit their application in blast furnace injection production. According to the calculation results of comprehensive performance evaluation indexes of different pulverized coal in blast furnace, the No.8, No.10, No.11 and No.12 pulverized coal were selected as pulverized coal into blast furnaces. Considering the different cost of pulverized coal, the No.12 pulverized coal was selected to inject into blast furnace can reduce the production cost most significantly.