| 摘要 |
<p>Provided is a method for operating a blast furnace, the method being capable of avoiding, particularly, a failure to heat a furnace top portion at low cost even in the case of performing a low-RAR operation (the reduction of carbon dioxide emissions). During the operation of a blast furnace using carbon iron composite as a portion of a charging material, one, two, or three of the injection temperature, injection rate, and vertical injection position of gas injected from a shaft portion are controlled in combination depending on a top gas temperature, whereby the decrease in temperature of the top gas is suppressed. Therefore, a failure to heat a furnace top portion can be avoided at low cost without significant capital investment even in the case of performing a low-RAR operation. Depending on the temperature of a shaft gas injected from the shaft portion, the vertical injection position of the shaft gas is adjusted to a position at which the inside temperature of the blast furnace is lower than the temperature of the shaft gas; hence, the inside of the blast furnace is not cooled by the shaft gas.</p> |
