JPH03215616A - Blast furnace operating method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for operating a blast furnace that prevents gas from blowing through the blast furnace. [Conventional technology] When gas blow-through occurs in a blast furnace, the gas is released outside the furnace without using the thermal energy it possesses, which often causes the inside of the blast furnace to cool and cause furnace conditions to deteriorate. .

[Problems to be Solved by the Invention] However, a method for predicting blow-by of gas generated in a blast furnace in advance has not been established.

The purpose of the present invention is to solve the above-mentioned problems of the prior art and provide a blast furnace operating method that can predict in advance the blow-through of gas generated in the blast furnace. :． Means for Solving Problem J The blast furnace operating method according to the first embodiment of the present invention continuously measures the blowing pressure of each tuyere, and determines whether the blowing pressure of any one of the tuyeres has a low r of 5. This is a blast furnace operating method in which the hot air control valve of the tuyere is throttled to prevent blow-through when the air pressure exceeds 0.08 kg/c per minute. Further, the blast furnace operating method according to the second embodiment of the present invention continuously measures the shaft pressure at a plurality of positions selected at approximately equal intervals in the circumferential direction of the shaft part, and is 0.05 in 5 minutes
kg/cnt or more, this is a blast furnace operating method in which the hot air control valve of the tuyere located at the bottom of that position is throttled to prevent blow-through.

[Function] The blast furnace operating method of the first embodiment according to the present invention continuously measures the blowing pressure of each tuyere, and the reduction in the blowing pressure of any one tuyere is 0.08 kg in 5 minutes.7 ' When the temperature exceeds c%, the hot air control valve for that tuyere is throttled to prevent blow-through. The reason is as follows. When we investigated the relationship between the probability of blow-through occurring and the blow pressure at the tuyere that had decreased over the past 5 minutes, we found that there was a relationship as shown in Figure 3. In other words, if the blowing pressure has decreased by 0.08 kg/1 or more in the past 5 minutes, the
It was found that 00% blow-through occurs. Therefore, in the first embodiment of the blast furnace operating method according to the present invention, the blowing pressure of each tuyere is continuously measured, and the blowing pressure of any one of the tuyeres decreases by 0.08 kg/cat or more in 5 minutes. When this occurred, the hot air control valve at the tuyere was throttled to prevent blow-through.

Moreover, the blast furnace operating method of the second embodiment according to the present invention is as follows:
Continuously measure the shaft pressure at multiple positions selected at approximately equal intervals in the circumferential direction of the shaft part, and when any shaft pressure decreases by 0.05 kg/cffl or more in 5 minutes, that position is determined. The hot air control valve of the tuyere located at the bottom of the tuyere is throttled to prevent blow-through. The reason is as follows. When we investigated the relationship between the probability of blow-through occurring and the shaft pressure that had decreased over the past five minutes, we found that there was a relationship as shown in Figure 4. That is, it was found that when the shaft pressure decreased by 0.05 kg/cffl or more in the past 5 minutes, blow-through occurred almost 100% of the time. Therefore, the blast furnace operating method according to the second embodiment of the present invention continuously measures the shaft pressure at a plurality of positions selected at approximately equal intervals in the circumferential direction of the shaft portion, and When the amount exceeded 0.05 kg/1 in 5 minutes, the hot air control valve of the tuyere located at the bottom of that position was throttled to prevent blow-through.

[Example] A blast furnace operating method according to a first example of the present invention will be explained with reference to FIG. Figure 1 compares the relationship between the decrease i (fluctuation range) of blast pressure and the probability of blow-through occurring in the blast furnace when the blast furnace operating method of the first embodiment of the present invention is implemented and the conventional operating method. This is a graph shown as follows. The solid line is the probability that blow-through will occur in the conventional operating method, and the dotted line is the probability that blow-through will occur in the blast furnace operation method of the first embodiment of the present invention.
Conventionally, 100% blow-through occurred when the blast furnace was above nl, but in the blast furnace operating method of the first embodiment of the present invention, blow-through occurred at 3.
It is around 0%, indicating that the blast furnace is operating more stably than before. Table 1 shows the operating performance of the blast furnace when the blast furnace operating method according to the first embodiment of the present invention was implemented in comparison with the conventional operating method.
Fuel ratio from 520 kg/Ton to 490kg/T
On, Si in pig iron was reduced from 0.42% to 0.30%
The furnace condition index improved from 75 to 91, both of which confirm the effects of the blast furnace operating method of the first embodiment of the present invention.

Table 1 A blast furnace operating method according to a second embodiment of the present invention will be explained with reference to FIG. Figure 2 shows the amount of decrease in shaft pressure (fluctuation range) when the blast furnace operating method of the second embodiment of the present invention is implemented.
This is a graph showing the relationship between this and the probability of blow-through occurring in a blast furnace compared to conventional operating methods. The solid line is the probability that blow-through will occur in the conventional operating method, and the dotted line is the probability that blow-through will occur in the blast furnace operating method of the second embodiment of the present invention.
g/cI+! In the above cases, blow-through occurred 100% in the past, but in the blast furnace operating method of the second embodiment of the present invention, the blow-through was about 30%, which indicates that the blast furnace is operated more stably than before. I understand. The operating results of the blast furnace were also similar to those of the blast furnace operating method of the first embodiment of the present invention (shown in Table 1).

[Effects of the Invention] According to the present invention, blow-through occurring in the blast furnace can be prevented and the furnace condition of the blast furnace can be stabilized.
content and improve the furnace condition index.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the amount of reduction in blast pressure and the probability of blow-through occurring in the blast furnace when the blast furnace operating method according to the first embodiment of the present invention is implemented, and FIG. A graph showing the relationship between the amount of reduction in shaft pressure and the probability of blow-through occurring in the blast furnace when the blast furnace operating method of Example 2 is implemented, and Figure 3 shows the amount of reduction in blast pressure and the probability of blow-through occurring in the conventional method Figure 4 is a graph showing the relationship between the amount of reduction in shaft pressure and the probability of blow-through occurring in a blast furnace in a conventional operating method.

Claims (2)

[Claims] (1) Continuously measure the blowing pressure of each tuyere, and find that the drop in blowing pressure of any tuyere is 0.08 kg/cm in 5 minutes.
A blast furnace operating method characterized in that when the temperature reaches 2 or more, the hot air control valve of the tuyere is throttled to prevent blow-through. (2) Continuously measure the shaft pressure at multiple positions selected at approximately equal intervals in the circumferential direction of the shaft, and determine if the drop in shaft pressure at any one of them is 0.05 kg/'cm^2 in 5 minutes.
A blast furnace operating method characterized in that when the above occurs, the hot air control valve of the tuyere located at the bottom of that position is throttled to prevent blow-through.