Blast furnace operation methods

Abstract

The objective is to provide a blast furnace operation method that can reach the target molten iron temperature or production volume in a short time, taking into account the time lags of both coke charge control and pulverized coal injection control. [Solution] The first blast furnace operation method includes a first step of measuring the molten iron temperature, a second step of determining the temperature difference between the molten iron temperature and the target molten iron temperature, a third step of obtaining a combination of coke and pulverized coal amounts from numerical calculation or a control table based on the temperature difference so that the molten iron temperature reaches the target molten iron temperature in the shortest time, and a fourth step of maintaining the coke and pulverized coal amounts obtained in the third step until the molten iron temperature reaches the target molten iron temperature. The second blast furnace operation method also includes a third step of obtaining a combination of coke and pulverized coal amounts from numerical calculation or a control table based on the difference between the amount of iron produced and the target amount of iron produced so that the amount of iron produced reaches the target amount of iron produced in the shortest time.

Claims

[Claim 1] A blast furnace operation method that controls the molten iron temperature to a target molten iron temperature by the amount of coke charged from the top of the furnace and the amount of pulverized coal blown in from the tuyeres. The first step is to measure the molten iron temperature, A second step involves determining the temperature difference between the molten iron temperature measured in the first step and the target molten iron temperature, A third step involves obtaining, based on the temperature difference obtained in the second step, the combination of coke quantity and pulverized coal quantity that allows the molten iron temperature to reach the target molten iron temperature in the shortest possible time, either through numerical calculation or a control table. A fourth step is to maintain the amount of coke and the amount of pulverized coal obtained in the third step until the molten iron temperature reaches the target molten iron temperature, A blast furnace operation method characterized by having [a certain feature]. [Claim 2] A blast furnace operation method that controls the amount of pig iron produced to a target amount of pig iron produced by the amount of coke charged from the top of the furnace and the amount of pulverized coal blown in from the tuyeres. The first step is to measure the amount of pig iron produced, A second step involves determining the difference between the amount of molten metal produced measured in the first step and the target amount of molten metal produced. A third step involves obtaining, based on the difference obtained in the second step, the combination of coke quantity and pulverized coal quantity necessary for the pig iron production amount to reach the target pig iron production amount in the shortest time, using numerical calculation or a control table. A fourth step is to maintain the amount of coke and pulverized coal obtained in the third step until the amount of pig iron produced reaches the target amount of pig iron produced, A blast furnace operation method characterized by having [a certain feature]. [Claim 3] The fifth step involves obtaining the combustion temperature of the tuyere tip, Prior to the fourth step, if the combustion temperature of the tuyere tip obtained in the fifth step is lower than the combustion temperature of the pulverized coal, a sixth step is taken to increase the amount of enriched oxygen gas blown into the normal tuyere, The blast furnace operation method according to claim 1 or 2, further comprising the above. [Claim 4] A seventh step involves separating a second reducing gas from the furnace top exhaust gas discharged from the furnace top, An eighth step involves heating the second reducing gas separated in the seventh step, The ninth step involves blowing the second reducing gas, which has been heated in the eighth step, into the shaft. The blast furnace operation method according to claim 1 or 2, further characterized by having the following features. [Claim 5] Step 10 involves heating the first reducing gas, which is a hydrogen-based reducing gas, outside the blast furnace system, Step 11 involves blowing the first reducing gas, which has been heated in step 10, into the blast furnace, The blast furnace operation method according to claim 1 or 2, further characterized by having the following features. [Claim 6] At least a portion of the pulverized coal contains biocoal. A blast furnace operation method according to claim 1 or 2.

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