JPS6043410A - Method for operating blast furnace by powder blowing - Google Patents

Abstract

PURPOSE:To correct the deviation of the deadman formed in the inside bottom of a blast furnace and to maintain a stable blast condition by blowing required exothermic powder together with blast gas into the furnace through the tuyere thereof according to the deviation of the deadman. CONSTITUTION:A deadman 6 having an approximately circular conical shape is formed in the central part of the hearth in a blast furnace 1 under operation by forming a charge build-up zone 2, a fusion zone 3, a melt dripping zone 4, a hearth well 5, etc. If the nonuniform flow of the molten iron and slag through tap holes 7, 8 and the unstability of the above-mentioned build-up zone are resulted from the deviation in the position and shape of the above-mentioned deadman 6 generated by the effect of the deposit, etc. in the furnace during operation of the furnace 1, such deviation is detected with a thermometer embedded in the outside circumferential furnace wall in the hearth part. Required exothermic powder is blown together with blast gas into the furnace through the tuyere according to such deviation to adjust the temp. in the hearth part, by which the deviation of the deadman 6 is corrected. Metallic powders such as pulverized coal, coke powder, ferrosilicon, Al, Mg, Ca, etc. are properly used as the above- mentioned exothermic powder.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method of operating a powder injection blast furnace, and in particular to adjusting (positioning) the dead man staying in the hearth of the furnace.

This is a proposal for a method to maintain stable furnace conditions by changing the shape of the furnace.

Conventional technology 1 yen is a layered charge accumulation zone consisting of ore and coke 2
, a cohesive zone 3, a melt dripping zone 4, and a hearth sump 9 section 5. A solidified mass of coke and pig iron, called a substantially conical det man 6, exists in an indefinite state in the approximate hearth portion of the hearth sump portion (hereinafter simply referred to as the hearth portion) 5. It is believed that there are. However, the position and shape of this dead man 6 change due to the influence of deposits lO in the furnace, etc., and sometimes it deviates sharply from the furnace core 11 as shown in Figure 2, and this state continues for a long time. Sometimes.

Such deviation in the position of the dead man 6 causes non-uniformity in the flow of hot metal and molten slag, as shown in FIG.

In other words, since there is a dead man 6 on the X-side tapping lower, the amount of hot metal and floating flow per unit time is reduced, and therefore the tapping time is also shortened, and the tapping and slag from both the x and y tapping lowers and 8 are reduced. Significantly unbalanced. As a result, are you worried about the furnace condition above the tuyere level and the nine-part charge descending situation? This impairs the smooth operation of the blast furnace.

Conventionally, in order to avoid inhibiting blast furnace operation due to the above-mentioned unbalanced detonation, a large amount of coke was charged from the top of the furnace.
The furnace was operated so that the deposits 10 on the furnace were made uniform around the furnace by increasing the furnace heat. However, this method has disadvantages in that it takes at least two weeks to uniformly remove the f1N and IO, and that it is not effective, as the fuel consumption rate also increases significantly.

Purpose of the Invention The object of the invention is to correct the above-mentioned drawbacks of the prior art, which is considered to be one of the factors that worsen the furnace condition of a blast furnace. The aim is to overcome this by using technology. Another object of the present invention is to mix T1-containing iron powder with the exothermic powder to maintain film retention on the furnace wall.

Structure of the Invention The present invention is characterized in that the basic furnace operation is performed so that the dead man observed in the hearth of the blast furnace is in an appropriate state. It is a preferable embodiment to locate it within the vicinity of the core, which is convenient for maintaining a stable furnace condition. If the furnace heat is stable in the direction of the furnace circumference, the det man 6 will stay at the appropriate position rj+>0, but if the furnace heat situation becomes uneven in the direction of the furnace circumference, the position of the det man 6 will be on the side with lower furnace heat. It gradually displaces.

Therefore, if heat is supplied intensively to the side where the furnace heat is low, it becomes possible to correct the deviation of the dead man 6.

When the heat is injected into the side where the furnace heat is insufficient, the following reaction occurs and heat is generated. In the way part, O (coal) + 3AOtb (gas) = C
O↑+2200 Reacts like KcaL4y-0 and generates heat, increasing the furnace heat.

For example, in the case of ferrosilicon, Fe-Si is 10% 0. (Gas) −(Fe)+(SiOg
)+8490 KOalt4. ,.

Due to the exothermic reaction of The flow rate of molten metal to the side tap hole increases and damages the furnace wall. In order to repair this, in addition to the above exothermic powder, T1
Powder (iron sand, etc.) is combined and blown into 'FiO+T' in the furnace.
The worn walls are repaired by forming titanium bears such as iN.

On the other hand, iron oxide-based powder is blown into the Y-side tap hole 8, which is far away from the drain man 6.

Next, a specific example of correcting the bias in the position of the dead man will be described. Figure 5 (a) and (b) show the arrangement of thermometers 9 buried in the furnace wall to determine the degree of deviation from the center of the hearth det man. When the temperature difference in the direction is 40"C or more, it is assumed that the det man is biased, and the powder injection adjustment as described below is carried out. Furthermore, the det man bias is caused by the deviation from the X-Y taphole. It can also be determined by differences in the tapping conditions (for example, tapping time, amount of slag tapped, etc.).

Now, FIG. 6 shows the calculated Dettman position determined by heat transfer calculation based on the indicated value of the thermometer (provided that the Dettmann solidification temperature is assumed to be 1150° C.). Based on this estimation, pulverized coal and re-si, (si%≧
Blow in 90% mixed powder equivalent to bo kg/l-p,
In contrast, 5 kg//1 J-p of iron oxide powder was injected from the remaining A9 tuyere 1 to I (x80 tuyere and A1 tuyere.The above mixing ratio was When considering the degree of damage to the nearby furnace wall, mix T1 powder,
Basically, considering the calorific value and slag-forming property of the powder, pulverized coal
5 parts by weight, Fe-5i, ao parts by weight + 15 parts by weight of Ti powder.

Figure 7 shows the temperature difference in the circumferential direction of the furnace before and after the mixed powder was injected from the A2 to A8 tuyeres. After 4 days, the temperature difference was 10°C, indicating that the dead man position had been corrected.

In a blast furnace with an internal volume of 2,500 m8 and 30 blowers, when the condition shown in Fig. 6 was reached, the above-mentioned mixed powder (pulverized coal 55,
Fe-5i 8o, Ti powder 15)k 5.
Table 1 shows examples of blast furnace operation when o Icg/l-p is injected from 2 to 8 tuyeres and iron oxide powder is injected from other tuyeres.
As is clear from the results shown in Figure 2, the differences in hot metal temperature and tap volume between tapholes disappeared, and fluctuations in slip and blast pressure decreased.

Effects of the Invention As explained above, according to the present invention, the deviation in the position of the dead man in the furnace can be quickly corrected, so that the operational impediments, such as the unrestrained dropping of the charge in the circumferential direction of the furnace, can be fixed in a short period of time. This can be resolved in time to achieve smooth blast furnace operation. Moreover,
Low fuel ratio operation has the effect of maintaining such smooth operation.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram showing the conditions inside the blast furnace, Figure 2 is an explanatory diagram of the estimation of the dead man level taking into consideration the influence of deposits on the furnace wall, Figures 8 and 4 are: Detsutoman's 11II! Figures M5 (a) and (b) are route maps showing the arrangement of thermometers to measure the furnace heat status. , FIG. 6 is an explanatory diagram showing the positional relationship between the low furnace heat area and the dead mantle, and FIG. 7 is a graph showing the change in temperature difference in the furnace circumferential direction before and after powder injection. 1... Blast furnace 2... Charge deposition zone 8... Cohesive zone 4... Melt dripping zone 5... Hearth sump 9 parts 6... Dettman 7.8...
Taphole 9... Thermometer 10... Adherence. Patent applicant: Kawasaki Steel Corporation Figure 4

Claims (1)

[Scope of Claims] L: In the operation of a blast furnace, in which various powders are injected into the furnace along with blowing gas from the siding to adjust the furnace condition, the detonation observed in the hearth of the blast furnace is A powder injection blast furnace operating method characterized in that the powder injection blast furnace is adjusted so as to be appropriate by injecting a required exothermic fluid from the tuyeres according to the conditions. The above exothermic powders include pulverized coal, coke powder, ferrosilicon powder, and metal aluminum. 2. The method according to claim 1, characterized in that magnesium scrap, calcium metal, etc. are used.