JPS6017004A - Operating method of blast furnace - Google Patents

Abstract

PURPOSE:To provide an operating method of a blast furnace without decreasing the void volume in the mixed layer formed near the furnace wall part by charging an iron raw material and coke having the smallest possible difference in grain size to the periphery of the furnace within a specific distance from the furnace wall. CONSTITUTION:An iron raw material 10 or coke 11 deposited on a large bell 7 is charged by a movable armor 9 into a furnace with, for example, a bell-type charger. The material 10 and the coke 11 to be charged to the peripheral part of the furnace within 1m from the furnace wall are charged into the wall after the grain size thereof is so adjusted as to attain 0.5-1.5 average grain size ratio thereof, i.e., after the grain size difference between both is minimized. The slip in the mixed layer of the material 10 and the coke 11 is thus considerably decreased, because the formation of the mixed layer having small void volume is substantially obviated and the elimination of the factors for growing deposit is made possible.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method of operating a blast furnace.

Prior Art In recent years, especially with the shift to all-coke operation, the importance of controlling gas flow near the blast furnace wall has increased. Many phenomena, such as the presence of sintered powder in the VC during shaft sampling and furnace wall wear at the upper part of the shaft, are deeply related to the descending behavior of iron raw materials and coke near the furnace wall, and to the gas flow. In order to maintain stable operation, it is important to accurately understand the filling structure of the iron raw material and coke near the furnace wall.

In the river, various detection devices such as profile meters and layer thickness sensors are used to sense and use, and it has become possible to obtain information on the falling speed and layer thickness of iron raw material and coke near the furnace wall. There is. Based on this information, the existence of a mixed layer of iron raw material and coke near the furnace wall has been confirmed. The existence of this mixed layer has already been confirmed in the dismantling survey of the Gods' blast furnace, but there are many questions about the filling structure of this mixed layer.

Therefore, the present inventors used a cold two-dimensional model of the blast furnace shaft shown in Fig. 1 to lower the iron raw material and coke charged in layers to form a mixed layer near the furnace wall. The filling structure was investigated.

Figure 2 i/(- As an example, the porosity of a mixed layer of sintered ore with an average grain size of 13.8 mm and coke with an average grain size of 50 corners generated near the furnace wall and the ratio of 1 volume of sintered ore shows the relationship between

As can be seen from FIG. 2, most of the porosity of the mixed layer generated in the vicinity of the furnace wall was extremely small, ranging from 0.30 to 0.35, resulting in poor air permeability.

The factors contributing to the formation of the double mixed layer include the condition of the furnace wall in the shaft section, the difference in average particle size between iron raw material and coke (currently iron raw material] 5-25 min + coke 50-55 min), and iron raw material and coke density difference (iron original -13,0 ~
4゜of/cnl + coke 0.9 ~ coke,
ofZ/ca), and as a result, the porosity is reduced, similar to when two types of particles with different particle sizes are mixed.

The generation of such a mixed layer with a small porosity in an actual furnace is
The amount of gas passing through the mixed layer decreases, and the temperature rise rate of the mixed layer is delayed, resulting in a low temperature sea near the furnace wall.
0°C to 600'C).

Therefore, blast furnace operating methods that do not generate a mixed layer are becoming increasingly important, but the current blast furnace wall structure (brickwork)
;j: The furnace wall is worn, and the formation of a mixed layer is unavoidable. Therefore, considering that the mixed layer has a packed structure with a small porosity, the solution to this problem is to devise an operating method that will prevent the porosity of the produced mixed layer from becoming small. This will lead to strategies.

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a method for operating a furnace that does not reduce the porosity of the mixed layer formed near the furnace wall.

Structure of the Invention The gist of the present invention is to specifically prepare iron raw material and coke with as little difference in particle size as possible so that the average particle size ratio between the iron raw material and coke is 0.
Furnace installation operation that makes it possible to suppress the decrease in porosity of the generated mixed layer as much as possible by charging around the furnace within ]-m from the furnace wall so as to enter the axial rotation of 5 to 5. It is the law.

A specific method for achieving the purpose of the present invention is as follows:
There are three methods as follows. That is, a method of charging small coke of 0 particle size, preferably small diameter coke of coke Omn+ to 30 cylinders to the peripheral part of the furnace wall to reduce the difference in particle size with the iron raw material. A method of charging 20 mm or more of -4~ to the periphery of the furnace wall to reduce the particle size difference with coke. ・ ■ Adjusting both the yaw 2f grain j length: and the iron raw material particle size to reduce the particle size difference There is a way to do it. Note that method (2) also leads to an increase in coke yield by using small-diameter coke, which has not been previously used.

Example Hereinafter, the present invention will be explained in detail based on Examples.

Figures 3 and 4 show examples of the iron raw material and coke charging method based on the present invention. FIG. Big bell 7 or the 4th bell in Figure 3
．． Iron raw material 1 deposited on fixed hopper 13 in the figure
1. Or coke 10 is 1 movable armor 9,
Alternatively, it is charged into the furnace through the in-furnace chute 12.

In the present invention, in the case of (2) in the previous h1, the coke and in the case of the above (2), the iron raw material are separated in advance into large and small diameter particles of a predetermined particle size, and at the time of charging, in the case (3), the small diameter coke is separated. In the case of (2), a large-diameter iron raw material is charged into the peripheral area of the furnace, and in the case of (2), the small-diameter coke and the large-diameter iron raw material with an average particle size of 20 to 30 mm are charged to form a mixed layer. The aim is to suppress the decrease in porosity of the mixed layer during formation.

FIG. 5 shows an example of the results of operation before and after the blast furnace A in which the present invention was implemented. Blast furnace A is a medium-sized blast furnace with an internal volume of 2,800 m. Here, in Example 2 of the present invention, the coke and iron raw materials shown in Table 31 are prepared in advance, and the particle size is
This is an operation method in which small-diameter coke of 11H is charged into the periphery of the furnace within a range of about 1 m from the furnace wall, and the difference in average particle size between the coke and the iron raw material in the periphery of the furnace is reduced. The ratio of the average particle size of iron raw material and coke around the octopus is set to 0.8 to 1.5. In Embodiment I of the present invention, the coke and iron raw materials shown in Table 2 are prepared in advance, and the iron raw materials with large grain sizes of 20 or more are charged to the peripheral area of the furnace, and the coke and iron raw materials in the peripheral area of the furnace are This is an operation method in which the difference in average particle size is reduced, and in this example, the ratio of the average particle size of iron raw material and coke in one stage around the furnace is set to 0.5 to 0.8. From an operational point of view, the average particle size ratio when reducing the particle size difference is preferably 0.8 to 2.

Table 1 7-Table 2 Effects of the Invention As can be seen from FIG. 5, the number of slips is significantly reduced by implementing the method of the present invention. This is due to the fact that the formation of a mixed layer with a low porosity is almost completely eliminated, making it possible to eliminate the factors that cause deposits to grow. and·
As shown in Figure 6, as a result of the stabilizing effect of furnace operation, a fuel ratio reduction of approximately 10 gg/t was achieved.

[Brief explanation of drawings]

8- Figure 1 shows a cold two-dimensional model of the blast furnace shaft. Figure 2 shows the porosity of the charge (ten coke of sintered ore) in the sampling unit when the test equipment shown in Figure 1 is used. FIGS. 3 and 4 are graphs showing the relationship between the weight ratio of sintered ore and the weight ratio of sintered ore. Figure 3 is a cross-sectional structural diagram of the upper part of a blast furnace to explain the iron raw material and coke charging method shown in Figure 3. FIG. 5 and FIG. 6 are examples of the operational results of the blast furnace before and after implementing the present invention. . 1...Shaft section furnace wall 2...Movable bottom 3...Drive device 4...Sintered ore 5...Coke 6... ...Furnace body 7...Large bell 8...Small bell 9...Mu~Haful Armor 10...Iron raw material 10-]...・Large diameter iron raw material 10-2...Small diameter iron raw material 11...Coke 11-1...Small diameter coke 11-2...Large diameter coke 12...Furnace chute 13...Fixed hopper applicant New Japan-! J! Tetsu Co., Ltd. Figure 1 11- Figure 2

Claims (4)

[Claims] (1) Iron raw materials and coke are sequentially charged in layers from the top of the furnace,
In the blast furnace operation method that performs refining, the average particle size ratio L of iron raw material and coke charged to the periphery of the furnace within m from the furnace wall (L - average particle size of iron raw material / average particle size of coke) A blast furnace operating method characterized by charging and operating after adjusting the particle size so that the particle size is 0.5 to 1.5. (2) Claim 1 which adjusts the particle size of coke
Furnace operation method described in section (3) The blast furnace operating method according to claim 1, which adjusts the particle size of the iron raw material. (4) The blast furnace operating method according to claim 1, which adjusts both the coke particle size and the iron raw material particle size.