| 摘要 |
PROBLEM TO BE SOLVED: To provide a blast furnace operation method that can improve the productivity and reduce the emitted COeven under an operating condition of a pulverized coal ratio of 150 kg/t-p or more.SOLUTION: When the strength of coke charged from blast furnace top is DI[%] 87 or less measured in accordance to a test method described in JISK2151, and at least two of the three conditions that the weight ratio of pulverized coal having particle size of 74 μm or less is 60% or less, the average volatile content of pulverized coal is 25 mass% or less and the blast air temperature is 1100°C or less, are met, burnable gas and inflammable gas are injected together with pulverized coal from lance, in the blast furnace operation method. In this case, the concentrations of burnable gas and inflammable gas are respectively maintained, as a gas concentration in lance, at 50 to 70 vol.% and 10 to 30 vol.%, and when the strength of coke is DI[%] 85 or less, maintained at 50 to 80 vol.% and 10 to 40 vol.%, and when the strength of coke is DI[%] 83 or less, maintain at 50 to 90 vol.% and 10 to 50 vol.%. |
