JPS62247011A - Method for charging ore to blast furnace - Google Patents

Abstract

PURPOSE:To always stabilize furnace conditions even if the grain size of ore is small and to make efficient operation by adjusting the grain size of the ore to be deposited on the wall side of a blast furnace to the average grain size or above of the ore to be charged into the furnace at the time of operating the blast furnace by changing a method for charging raw materials. CONSTITUTION:The ore is dropped with the position slightly nearer the central 1 side than the furnace wall 2 as a falling point from an armor plate 6 when, for example, the blast furnace is of a bell type. The charging of the raw materials to the blast furnace is executed in such a manner that coke layers 3 and ore layers 4 are alternately laminated. Dw is adjusted to >=-D when the grain size of the ore 5 to be deposited on the furnace wall 2 side is designated as Dw, and the average grain size over the entire part of the ore to be charged as -D. The gaseous flow distribution in the blast furnace is thus optimized by charging the ore 5 into the furnace and permitting the control thereof. The operation of the blast furnace is thus controlled stably with decreased slips.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of charging ore to a blast furnace.

[Prior Art] In order to stably and efficiently operate a blast furnace, it is extremely important to optimize the gas flow distribution rising inside the furnace.

Normally, this gas flow distribution is controlled by feeding raw materials into the furnace.If you want to flow a large amount of gas into the center of the furnace, place coke with low ventilation resistance in the direction of the center of the furnace, and place ore with high ventilation resistance into the furnace wall. It is common to charge in the direction.

In other words, ventilation resistance is given as a function of particle size and porosity of the electroplated layer, and as both particle size and porosity become smaller, ventilation resistance increases. Particle diameters are approximately 50mm and 17m, respectively.
m, it is based on the fact that the ventilation resistance is naturally greater for ore than for coke.

However, if too much gas is allowed to flow into the center and the amount of gas on the furnace wall is reduced, the furnace wall becomes inactive and deposits are formed, making stable operation impossible.

On the other hand, if the amount of gas in the center is reduced and the gas in the furnace wall is allowed to flow excessively, heat loss from the furnace wall will increase, and in extreme cases, the furnace wall will be damaged.

6 - I - h 1 ri d mi t
) −1…I + − to L 7χ”;
The key point in blast furnace operation is how to maintain the lIv-resistance.

Blast furnace operators are making efforts to optimize the gas flow distribution, but it is difficult to maintain an appropriate gas flow distribution when there are changes in the physical chemistry of the charging material or changes in production volume. I often experience being unable to do things.

[Problems to be solved by the invention] By the way, this phenomenon often occurs when the particle size of the ore becomes small, and in this case, the temperature inside the bricks in the furnace wall decreases, causing this part to become inactive. As a result, there was a serious problem in that the furnace conditions became unstable and the required production volume could not be obtained.

Conventional countermeasures when such a situation occurs is to restore the flow of gas in the furnace wall by charging coke, which has a lower ventilation resistance, toward the furnace wall side relative to ore, which has a higher ventilation resistance. was.

However, the number of small ores becomes relatively small, and even if the gas flow on the furnace wall is restored to a certain extent, small ores still exist in the furnace wall, so the furnace condition often does not recover completely. It has been pointed out that

Therefore, the present invention operates by controlling the grain size of the ore on the furnace wall so that it does not exceed a certain value, even if the particle size of the ore becomes small, while minimizing the accumulation of the small ore on the furnace wall. It was created with the aim of providing a method for constantly stabilizing the furnace condition and operating it efficiently.

Means for Solving Problem E] The present invention provides a method of operating a blast furnace while controlling the gas flow distribution in the furnace by changing the method of charging raw materials into the blast furnace.
The present invention relates to a method of charging ore to a blast furnace, characterized in that the ore is charged so that the particle size of the ore to be deposited on the wall side of the blast furnace is equal to or larger than the average particle size of the ore charged into the blast furnace.

Hereinafter, the basic concept of the present invention will be explained using FIGS. 1 to 5.

In Fig. 1, 1 is the center of the blast furnace, and 2 is the wall of the blast furnace. Raw materials are charged into the blast furnace by alternately stacking coke layer 3 and ore B4 as shown in the figure. In the present invention, when the particle size of the ore 5 deposited on the furnace wall 2 side of the blast furnace is (Dw), and the average particle size of the entire charged ore is (D), D w / The ore is charged into the blast furnace so that the relationship D≧1 is established.

There are various methods for charging and depositing ore so as to satisfy this relational expression, as described below.

The first method is adopted when the blast furnace is of the bell type, and the ore is dropped from the armor plate 6 with the falling point slightly closer to the center than the furnace wall 2, as shown in Figure 2. It's a method.

This method utilizes the empirical rule that when ore is dropped, relatively small-diameter ore is deposited near the falling point, and as a result, ore is deposited on the wall 2 side of the blast furnace. The grain size (Dw) of the ore that is produced is larger than the average grain size ('5), and ore with a small grain size is deposited near the falling point, and ore with a large grain size is deposited near the center 1 of the blast furnace. become.

The second method is adopted when the blast furnace is a bell-less type, and as shown in Fig. 3, charging is carried out using a rotating chute 7 with a position slightly closer to the center than the furnace wall 2 as the dropping point. Is possible. This method also uses the above-mentioned empirical rule.

The third method is to charge according to particle size, and as shown in Figure 4, an example of a bellless blast furnace, ore 8 with a small particle size is first charged to the center 1 side, and then the ore 8 is charged to the center 1. The ore 9 having a large particle size is charged near the furnace wall 2.

The fourth method, as shown in the example of a bellless blast furnace in 5UgJ, is based on the charging level (S, L). The above-mentioned empirical rule is also used in this method.

For example, if the charging is performed in Figure 5 and the bell is set high as S and L (1), the falling point of the ore will be a little closer to the center than the furnace wall 2, and will be near the furnace wall 2. Ore with large grain size will be deposited, but if S and L are set low as in (2), the falling point of the ore will be near the furnace wall 2, and ore with small grain size will be deposited near the furnace wall. Become.

Therefore, by changing the charging level in this way, the particle size of the ore near the furnace wall 2 can be controlled.

[Function] As in the present invention, by charging the ore so as to have the relationship (Dw/?j ≧ 1), an appropriate gas flow distribution is maintained on the furnace wall 2 side, and the gas flow is prevented by excessive gas flow. It is possible to prevent damage to the furnace wall 2 and, conversely, to prevent the formation of deposits on the furnace wall 2 due to inactivation, and it also dramatically reduces the number of slips, which is a representative factor representing the furnace condition. , the stable operation of the blast furnace can be maintained.

Conventionally, as shown in FIG. 9, ore was simply charged near the furnace wall 101 and allowed to flow toward the center side 102 of the blast furnace to form an ore layer 103.
Ore with small grain size was deposited in the vicinity, the above relationship was not realized, and the value of Dw/D was smaller than 1. Furthermore, a charging method that focuses on this value has not been established.

The present invention focuses on the significance of adopting this value of Dw/D as a control value, finds a method to increase this value to 1 or more, and by controlling it, it is possible to perform stable operation management of a blast furnace. .

[Example] Next, an example of the present invention will be described using FIGS. 6 to 8.

In order to clarify the relationship between the grain size of the ore deposited on the blast furnace wall and the furnace conditions, the charge deposited near the furnace wall 12 was sampled with a sampler 11 as shown in Figure 6, and the grain size of the ore was measured. investigated.

Figure 7 shows the relationship between ore particle size and furnace conditions.

The horizontal axis of the figure shows the ratio of the particle size (DW) of the ore near the furnace wall 12 to the average particle size (D) of the charged ore, and the vertical axis shows the number of slips, which is a typical factor representing the furnace condition. It is something.

As is clear from the figure, when the value of Dw/fi is 1°0 or more,
That is, it can be seen that when the particle size of the ore near the furnace wall 12 becomes equal to or larger than the average radius of the charged ore, the number of slips decreases significantly.

FIG. 8 shows an example in which blast furnace work was carried out using this value of Dw/T) as a control value.

The ore charging method in this case is the fourth method explained in the [Function] column, and the charging level (S
, L) to make the value of D w /D greater than or equal to 1.

In Figure 3, March 1st is the adoption of the control value 1 f-
271 days-r island G1. f) This is when the charging level was reduced from 2.2 m to 1.7 m in order to make the w/D straightness 10 tons. This action completely changed the operation where there was a lot of slip, and now stable furnace conditions with less slip can be achieved.

After that, in mid-March, the value of D w / 5 became less than 1.0, but by reducing the charging level from 1.7 m to 1°5 m, the value of D w / D became more than 1.0. Once the plant was restored, it became possible to operate stably for a long period of time.

[Effects of the Invention] As described above, the present invention charges the ore to be deposited on the wall side of the blast furnace so that the particle size is equal to or larger than the average particle size of the ore charged into the blast furnace, and further controls this. This made it possible to optimize the gas flow distribution within the blast furnace and to achieve stable blast furnace operational management with little slip.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing the basic concept of the present invention, Figure 1 is a diagram showing the state of the ore layer and coke layer in the blast furnace, and Figures 2 to 5 are diagrams showing the state of the ore layer and coke layer in the blast furnace. FIG. Figure t56 is a schematic diagram showing the state in which the hesambler is charged into the blast furnace. FIG. 7 is a graph showing the relationship between ore particle size and furnace conditions. The axis shows the number of slips, which is a representative factor representing the furnace condition. Figure 8 is a graph showing the situation when the blast furnace is operated by controlling the control value D w / D. The vertical axis shows the number of slips, D w / D, and the control status of the charging level, and the horizontal axis shows the control status of the slip count, D w / D, and charging level. Indicates between wi. FIG. 9 is a diagram showing a conventional method of charging ore into a blast furnace. 1... Center of the blast furnace 2... Furnace wall 3... Coke layer 4... Ore layer 5... Ore deposited on the furnace wall side 6... Armor plate 7... Rotating chute 8 ...Ore with small particle size 9...Ore with large particle size 11...Sampler 12...Furnace fi 101.
... Furnace wall 102 ... Center of blast furnace 103 ... Ore layer l ... Center of blast furnace 2 ... Furnace wall 3 ... Coke layer 4 ... Ore layer 5 ... On the furnace wall side Ore deposited 6...Armor plate 7...
Rotating chute 8...Ore with small particle size 9...Ore with large particle size Fig. 5 Fig. 6 Average particle size of ore (D) Fig. 8 Fig. q

Claims (1)

[Scope of Claim] In a method of operating a blast furnace while controlling the gas flow distribution in the furnace by changing the method of charging raw materials into the blast furnace, the particle size of ore to be deposited on the wall side of the blast furnace is adjusted. A method for charging ore into a blast furnace, characterized by charging the ore so that the particle size is equal to or larger than the average particle size of the ore to be charged.