JPH03215613A - 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 Application Field] The present invention relates to a blast furnace operating method for enriching hot air blown into a blast furnace with oxygen to increase hot metal production efficiency. [Prior art] The following methods are available to increase the production efficiency of hot metal per unit time in a blast furnace. (1) Increase the amount of hot air supplied to the blast furnace. (2) Increase the proportion of oxygen contained in hot air. (3) Reduce coke ratio.

[Problems to be solved by the invention] However, there are the following problems with the conventional method of increasing the production efficiency of hot metal per unit time in a blast furnace. The upper limit of the ratio was thought to be around 2.4. 1) Method of increasing the amount of air blown. ■ There is a limit to the blowing capacity of the blower. ■ Occurrence of gas blow-through and fluidization of the charge at the top of the furnace. ■ Occurrence of flooding phenomenon in the droplet layer at the bottom of the furnace. ■ Unstable gas flow in the blast furnace.

(2) A method of increasing the proportion of oxygen.

■　Increase in tuyere tip temperature.

■ Increase in the ratio of the heat of the hot air to the sensible heat of the charge, that is, the heat flow ratio.

The graph in Figure 3 shows the relationship between the oxygen enrichment rate and the furnace condition index in conventional blast furnace operation.When the oxygen enrichment rate exceeds 2%, the furnace condition index deteriorates; could not be enriched. In addition, the graph in Figure 4 shows the relationship between the tuyere tip temperature and the furnace condition index.
If the temperature exceeds , the furnace condition index deteriorates, and from this point of view there was also an upper limit to oxygen enrichment. Furthermore, as shown in the graph of FIG. 5, when the heat flow ratio exceeds 0.85, the furnace condition index deteriorates, indicating deterioration of the furnace condition due to oxygen enrichment.

As shown in the graph in Figure 6, productivity decreases as the furnace condition index decreases, and if the production capacity when the furnace condition index is 80 is 1, then the production capacity decreases to about 0.6 when the furnace condition index is 40. The percentage decreases.

(3) Method of reducing coke ratio. ■　Increase in tuyere tip temperature.

■ Decrease in furnace heat level. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for controlling gas flow rate in a blast furnace, which can extremely locally increase or decrease the gas flow rate near the furnace wall.

[Problems and Means for Solving the Problems] The first blast furnace operating method according to the present invention is a blast furnace operating method in which hot air is enriched with oxygen and, at the same time, water vapor is added as moisture through the tuyere. In addition, in the blast furnace operating method as an embodiment of the first blast furnace operating method, the addition ratio of moisture is 10 to 10 per 1% oxygen enrichment rate.
15g/Nm'. The second blast furnace operating method according to the present invention enriches hot air with oxygen, and at the same time selects the moisture to be added from any one of tap water, industrial water, sewage, and cheap water. This is a method of operating a blast furnace in which the material is added from the siding through a pipe different from a hot air pipe. [Operations] The first blast furnace operating method according to the present invention enriches hot air with oxygen and simultaneously adds water vapor as moisture through the tuyere. The reason is as follows. In other words, as shown in the graph of Figure 1, when operating a blast furnace with an oxygen enrichment rate exceeding 2%, when water vapor is added as moisture, the furnace condition index increases to an oxygen enrichment rate of less than 2%. There was no change over time. Therefore, in the first blast furnace operating method according to the present invention, while enriching the hot air with oxygen, water vapor is optionally added as moisture. In addition, in the blast furnace operating method as an embodiment of the first blast furnace operating method, the addition ratio of moisture is 10 to 10 per 1% oxygen enrichment rate.
15 g/'Nll'. The reason for this is as follows. By varying the addition ratio (g/Nm') of added moisture per 1% oxygen enrichment rate, the production increase effect (% that could be increased based on the conventional pig iron production ratio of 2.4) was calculated. We investigated the relationship between As a result, as shown in Figure 2, when the moisture addition rate is less than log/Nm', the flame temperature decreases and the furnace condition deteriorates due to the effect of moisture addition, and the moisture addition rate decreases. If it exceeds 15g/Nm3, there is too much moisture and the flame temperature rises, worsening the furnace condition.
The furnace condition is most stable when the moisture addition ratio is 10.
It was found to be between 15 g/Nm'. Therefore, in the blast furnace operating method as an embodiment of the first blast furnace operating method, the moisture addition rate is 10 to 1% per 1% oxygen enrichment rate.
It was set at 5 g/Nm3.

The second blast furnace operating method according to the present invention enriches hot air with oxygen, and at the same time selects the moisture to be added from any one of tap water, industrial water, sewage, and ammonium water. This is a method of operating a blast furnace in which the material is added from the tuyere using piping different from the hot air pipe. The reason is as follows. When enriching hot air with oxygen in the same way as water vapor, clean water, industrial water, sewage, and ammonium water were added through the tuyere via a separate pipe from the hot air pipe. As a result, exactly the same effect as water vapor was obtained, so in the second blast furnace operating method according to the present invention, the hot air is enriched with oxygen, and at the same time, the added moisture is The moisture was added from the tuyere through piping different from the hot air pipe.

[Example] In a blast furnace operating method according to an embodiment of the present invention, the oxygen enrichment rate of the hot air is set to 2 to 4%, and the moisture is added to the oxygen enrichment rate of 1%.
10 to 15 g/N+a3 per % was added and blown into the furnace from the blast furnace tuyere. As a result, the conventional highest pig iron production ratio of 2
．． 4, we were able to achieve a 10-15% increase in production.

Table 1 shows the operating conditions (oxygen enrichment rate, moisture addition rate) of three cases in which the blast furnace operating method of one embodiment of the present invention was implemented.
and operational performance (tuyere tip temperature, heat flow ratio, furnace condition index, production volume,
This table summarizes the pig iron tap ratio and compares it with the conventional case.
In both cases, the production volume is higher than in the conventional case, and a production increase effect of 10 to 20% can be seen. Table 1 [Effects of the Invention] The present invention has made it possible to increase the production of hot metal beyond the conventional level.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the oxygen enrichment rate and the furnace condition index in the method of the present invention in comparison with the conventional method, and Figure 2 shows the relationship between the moisture addition rate and the production increase effect (%). Graph diagram, 3rd
The figure is a graph showing the relationship between the oxygen enrichment rate and the furnace condition index in the conventional method, Figure 4 is a graph showing the relationship between the tuyere tip temperature and the furnace condition index, and Figure 5 is the heat flow ratio and the furnace condition index. Figure 6 is a graph showing the relationship between furnace condition index and production capacity.

Claims (3)

[Claims] (1) A blast furnace operating method characterized by enriching hot air with oxygen and simultaneously adding water vapor as moisture through the tuyere. (2) Moisture addition rate is 10 to 1 per 1% oxygen enrichment rate.
2. The method of operating a blast furnace according to claim 1, characterized in that the pressure is 5 g/Nm^3. (3) At the same time as enriching the hot air with oxygen, select the moisture to be added from one of tap water, industrial water, sewage, and ammonium water, and add this moisture to the tuyere through piping different from the hot air pipe. A blast furnace operating method characterized by adding from.