| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace, capable of improving combustion temperature, accordingly capable of achieving a reduction in CO<SB POS="POST">2</SB>discharge. <P>SOLUTION: A lance 4 for blowing fuel from a tuyere 3 is formed as a double tube; oxygen is blown from outside tubes of two double tube lances 4 while pulverized coal is blown from inside tubes of the two double tube lances 4; and an oxygen concentration of a gas composed of a carrier gas of the pulverized coal and the gas blown from the outside tubes is adjusted to be 35 vol.% or higher. Thereby, even in a high pulverized coal ratio operation where a volatile matter of the pulverized coal is 25 mass% or lower and a ratio of the pulverized coal is 150 kg/t-pig iron or higher, a combustion temperature can be increased, and accordingly, a reduction in CO<SB POS="POST">2</SB>discharge can be achieved. When the ratio of the pulverized coal is 170 kg /t-pig iron or higher, the oxygen concentration is adjusted to be lower than 70 vol.%. The double tube lances 4 are arranged so that pulverized coal streams which are blown from the two double tube lances 4 are not overlapped, and thereby, the pulverized coal streams are prevented from getting dense and combustion efficiency can be secured. <P>COPYRIGHT: (C)2013,JPO&INPIT |
