| 摘要 |
PURPOSE: A method for injecting steam into blast furnace is provided to maintain combustion temperature properly during injection of a small quantity of pulverized coal as well as during injection of a large quantity of pulverized coal by controlling moisture content more accurately considering atmospheric humidity. CONSTITUTION: The method for injecting steam into blast furnace comprises the steps of obtaining a moisture injection amount in which value of theoretical flame temperature (Tf) is in the range of 2,100 to 2,250 deg.C using the following relational expression 1 in case that an injection quantity of pulverized coal is 60 ton/hr or less:£Relational Expression 1|, Tf=£{1,559+(0.839xBT)}-{(injectionWH2O/1,000)x6,033}|-£{(16,666xPCI)/(VB)}x3|+£{4,973/VBx60}O2|, where BT: blowing temperature (deg.C), injectionWH2O: moisture injection amount (g/Nm¬3), PCI: pulverized coal injection amount (ton/hr), VB: blowing amount (Nm¬3/min), and O2: oxygen injection amount (Nm¬3/hr), and injecting steam in accordance with the obtained moisture injection amount; measuring atmospheric temperature and atmospheric humidity in case that the injection quantity of pulverized coal is 60 ton/hr or more, and obtaining atmospheric moisture amount (atmospheric WH2O) by the following relational expression 2 using the measured values:£Relational Expression 1|, atmospheric WH2O={4.953+(0.3311xT)+(0.0111xT¬2)+(0.00038xT¬3)}xM/100, where atmospheric WH2O: atmospheric moisture amount (g/Nm¬3), M: atmospheric moisture content (%), and T: atmospheric temperature (deg.C); and obtaining an injection requiring steam amount (FS) (ton/hr) by the following relational expression 3 using the moisture injection amount (WH2O) obtained using the above relational expression 1 and atmospheric moisture amount (atmospheric WH2O) obtained by the above relational expression 2:£Relational Expression 3|, injection requiring steam amount (FS)=(injection WH2O-atmospheric WH2O)xVBx60/10¬6, and injecting steam into tuyeres according to the obtained injection requiring steam amount.
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