| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reducing reaction efficiency by lowering a hot heating zone temp. in a blast furnace and to obtain a good quality pig iron by blowing low temp. inert gas or low temp. reducing gas into the furnace from the lower part of a shaft part. SOLUTION: The low temp. inert gas or the low temp. reducing gas is blown into the furnace from a blowing pipe 10 set at the lower part of the shaft part and forcibly cooled in the furnace to lower the hot heating zone temp. Or a sucking pipe 12 for sucking the reducing gas from the center part of the furnace top, is set at the furnace top part, and the sucking pipe 12 and the blowing pipe 10 are connected with a connecting pipe 13 through the sucking means of a pump. In the connecting pipe 13, a heat exchanger 14 for cooling the reducing gas is interposed. As the inert gas, N2, Ar, etc., are used and as the reducing gas, gas consisting essentially of CO, H2 and N2 by reforming OCG gas or furnace top gas, are used. In this operational method, as a solid fuel, it is desirable to use coke having small lump and high reactivity, and to control the hot heating zone temp. to 700-900 deg.C.
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