JPH0230707A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To secure suitable molten iron flow and to obtain the stable operation and the long service life in a blast furnace by comparing furnace bottom temps. continuously measured with plural furnace bottom thermometers and furnace bottom temp. at the time of stopping the blast and controlling cooling water rate at the furnace bottom and charging rate and charging position of Ti source. CONSTITUTION:The differences DELTATi between each furnace bottom temps. Ti [(i) is the measuring positions at 1-n] continuously obtd. with the furnace bottom thermometer embedded at plural positions (n positions) at the bottom part in the blast furnace and the furnace bottom temps. Toi [(i) is measuring positions] beforehand measured at the time of stopping the blast (=Ti-Toi), are always calculated. Successively, the cooling water rate at the furnace bottom and the charging rate and the charging position of titanium source are controlled and changed so that each value in these differences DELTATi becomes to the prescribed value, respectively. By this method, while continuously assuming fluidizing behavior of molten iron in molten iron basin part, the molten iron flow is controlled to the suitable level at any time to obtain the stable operation and the long service life in the blast furnace.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the operation of a blast furnace in which the flow condition of hot metal in the blast furnace sump is estimated from the furnace bottom temperature to ensure an appropriate flow of hot metal. Regarding the law.

(Prior Art) The flow behavior of hot metal in a blast furnace sump closely corresponds to the furnace conditions of the blast furnace, and ensuring an appropriate flow of hot metal is essential for blast furnace operation. On the other hand, if hot metal flows locally at the bottom of the furnace, this will promote damage to the bottom bricks at that location, so controlling the flow of hot metal is important from the perspective of extending the life of the blast furnace.

Therefore, when operating a blast furnace, it is necessary to constantly understand the flow behavior of hot metal in the sump and to be able to manage the flow of hot metal at an appropriate level.

Conventionally, for example, Japanese Patent Application Laid-Open No. 6214620
6. In Japanese Patent Publication No. 57-47730, a tracer such as a radioactive element is introduced into the blast furnace through the tuyere, and from the emission behavior when the tracer is contained in the hot metal and discharged from the furnace,
A method for estimating the flow behavior of hot metal in a hot water tank is disclosed. Although this method is excellent in that it can estimate how much hot metal is being consumed based on the coke filling state in the blast furnace, on the other hand, it can only be measured intermittently, and
When using radioactive elements as tracers, there is a problem in that they must be handled and managed carefully.

(Objective of the present invention) An object of the present invention is to solve the problems of the prior art described above, and while continuously estimating the flow behavior of hot metal in the sump, the flow of hot metal can be adjusted to an appropriate level at any time. The objective is to provide a method of operating a blast furnace that can be managed in a controlled manner.

(Structure of the Invention) The present invention provides a furnace bottom temperature (Ti; i is 1 to n at the measurement position) that is continuously obtained from a plurality (n) of furnace bottom thermometers embedded in each position at the bottom of the blast furnace. The difference ΔTi (=
Ti-TO+) is constantly calculated, and the amount of cooling water at the bottom of the furnace and the charging amount and charging position of the titanium source are controlled so that each of ΔTi reaches a predetermined value.

In other words, the bottom temperature of a blast furnace is controlled not only by the hot metal-brick heat transfer coefficient (hp), which corresponds to the hot metal flow velocity (Vm), but also by the residual thickness of the bottom brick (1), etc. It is difficult to directly estimate Vn+ from the hearth bottom temperature. However, as shown in Figure 1, when the blast furnace is closed, the flow velocity of hot metal becomes 0, and the heat transfer coefficient (hp) between hot metal and bricks at that time is hpl over the entire bottom of the furnace.
becomes. Along with this, the hearth bottom temperature decreases to a value (TO, , TO□ to TOn) corresponding to the remaining amount of bricks. On the other hand, in an operating blast furnace, hot metal flows at a certain speed at each location in the furnace, and accordingly the HP is the value at rest (
hpl). Therefore, the hearth bottom temperature during operation shows a higher value (T, , T2 to Tn) than when the wind is not in operation. Therefore, if the hearth temperature difference ΔTi during operation and at rest is calculated for each hearth bottom position, the value depends only on the flow condition of the hot metal, and the appearance of the remaining thickness of the bricks can be ignored. Here, it can be determined that the larger the hearth bottom temperature difference ΔTi, the faster Vm at that position.

Here, a thermocouple is generally buried in the bottom of the blast furnace.
Since the measured value (hearthstone temperature) can be obtained continuously, ΔTi can be calculated at any time by recording the hearth bottom temperature (To i) at each position when the wind is off. The flow situation can be ignored. If the flow behavior of hot metal in the sump deviates from a predetermined level, the amount of cooling water at the bottom of the furnace, the amount of titanium source charged, and the charging position are changed. In other words, when the flow of hot metal becomes active over the entire bottom of the furnace (when ΔTi becomes large), the amount of cooling water at the bottom of the furnace and the amount of titanium source charged are increased, and vice versa. All you have to do is take the following measures. Furthermore, when it is detected that hot metal is locally flowing on the furnace wall side, the titanium source is selectively charged to the furnace wall side. Of course, when implementing such measures, it is desirable to check the effects from the change in ΔTi and consider whether to continue the measures. In addition, an appropriate ΔT
differs depending on the blast furnace, so ΔT can be determined from data during stable operation.
It is necessary to determine the control value of

Examples of the method of the present invention will be described below.

(Example 1) The bottom temperature of the furnace was continuously measured using thermocouples provided at the positions shown in FIG. 2, and ΔTi at each position was calculated. The transition of ΔTi is shown in FIG. As seen in the figure, after time A, there was a tendency for ΔT to decrease over the entire area inside the furnace. Therefore, the charging unit of titanium oxide was reduced to 5 kg.
/TK a little, and the amount of cooling water at the bottom of the furnace is 100T/+1
Lowered. Thereafter, 8T began to rise after 20 hours had passed, and recovered to its original level after another 40 hours.

5 (Example 2) ΔT was determined using the same method as in Example 1, and the value was monitored.

In this case, as shown in FIG. 4, only the ΔT on the furnace wall side began to rise from time B, and there was concern that the bricks on the furnace bottom wall would be damaged. Therefore, sintered ore containing 0.15% titanium oxide was charged from the top of the blast furnace in an amount equivalent to 20% of the charged raw material, and the sintered ore was selectively transferred using a movable armor. It was charged to the furnace wall side. As a result, ΔT on the furnace wall side began to decrease after 35 hours, and then recovered to the heavenly level.

(Effects of the invention) By using the method of the present invention, the flow behavior of hot metal in the blast furnace sump can be grasped at any time, so whether the behavior is in the direction of worsening the furnace condition or causing damage to the bottom bricks. When you are heading in the right direction, you can take timely measures. Therefore, it can contribute to the stable operation and long life of blast furnaces.

4. Brief explanation of the figure FIG. 1 shows the concerns of the method of the present invention.

Figure 2 is a schematic diagram of the side temperature position when the method of the present invention is implemented;
Furthermore, FIGS. 3 and 4 show changes in ΔT.

Claims (1)

[Claims] Each hearth bottom temperature (Ti; i is 1 to n at the measurement position) continuously obtained from hearth bottom thermometers buried at multiple (n) positions at the bottom of the blast furnace, and during wind down periods measured in advance. hearth temperature (
TOi; i is the measurement position) and the difference ΔTi (=Ti−TOi
) is constantly calculated, and the amount of cooling water at the bottom of the furnace, the amount of titanium source charged, and the charging position are controlled so that each value of ΔTi becomes a predetermined value.