JPS5950102A - Operating method of blast furnace - Google Patents

Abstract

PURPOSE:To perform stable operation of blast furnace for a long period of time by determining the control values which indicate quantitatively the deposited state of charge in the furnace and controlling various charging conditions, etc. so as to maintain the deposited layer of the charge in the furnace within the range of said control values. CONSTITUTION:The distance from the inside wall 1 of a furnace up to the position 3 in the crest part of the charge deposited layer is designated as L, in the deposited layer of the charge in the radial direction of the charge in the furnace. The deposition angle of the slope 5 of the layer on the central part side of the furnace is designated as theta1 and the deposition angle of the slope 4 of the layer on the wall 1 side as theta2. The values L, theta1, theta2 are so controlled so as to maintain 0.5-1.5m for L for both ore and coke, and 23-35 deg. theta1 and within + or -10 deg. for 2 for coke and 20-30 deg. theta1 and within + or -10 deg. theta2 for ore. The deposited state in the furnace is thus maintained to provide a target distribution of gaseous flow.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blast furnace operating method, and in particular, determines control values for the shape of the charge distribution in the radial direction of the furnace at the top of the furnace, and ensures that this is within a predetermined range. We propose a method suitable for stable blast furnace operation over a long period of time by controlling the burden distribution.

Generally, when operating a blast furnace, it is necessary to always know how the charge is distributed in the furnace, or how far the surface of the charge layer is in the direction of the furnace height. . Recently, an oblique profile measuring device as shown in No. 11N and a μ wave type profile measuring device as shown in Fig. 2 have been developed, and the state of charge accumulation in the furnace G can be grasped to some extent clearly. Now you can. However, the state of charge deposition in actual operation not only changes due to differences in the particle size composition of the raw material and the gas flow in the furnace, but also changes significantly by adjusting the bellless chute Yamu Pable Armor, which is a furnace top distribution control device. 8I4 becomes.

However, at present, it is not enough to simply measure the surface shape of the charge, but the question of what kind of profile should be adjusted for distribution has not yet been quantified, and the method relies on the intuition of the operator. It was a process of trial and error. Therefore,
Once the operating condition of the furnace became unstable, it not only took a long time to recover, but it was also impossible to operate the blast furnace stably over a long period of time.

The present invention was invented in order to solve the above-mentioned drawbacks of the prior art, and it is possible to accurately reflect the fluctuation of the gas flow in the furnace which changes from time to time in the furnace, and to deposit the charge in the furnace that changes together with the flow of gas in the furnace. It is characterized by stable operation by setting control values that quantitatively indicate the state and adjusting various charging conditions etc. so that the deposited layer of the in-furnace contents falls within the range of the control values. The purpose of this report is to propose methods for operating blast furnaces. In short, the present invention deals with the state of the charge deposit layer:
In other words, by setting a control value that indicates the distribution of debris to be controlled so as to achieve a reasonable gas flow distribution in the furnace, and performing feedback control, blast furnace operation can be achieved without much fluctuation relative to the operational target. This is the method that made it possible to do this. The gist of its configuration is that the gas flow distribution inside the blast furnace can be changed by changing the piled head of the contents inside the blast furnace! fil
lll1l L, in the method of performing blast furnace operation P, the charge accumulation layer in the furnace radial direction G is defined as the distance from the inner wall of the furnace to the peak, and L is the distance from the inner wall of the furnace to the peak, and The side charge layer deposition angle on the side charge layer deposition slope is θ], and when the side charge layer deposition angle on the furnace wall side is 02, their values L,
θl and θ2 are L: 0.5 to 1.5 for both ore and coke.
m, and when the charge layer is coke,
θ1: 25° to 35° 02: Within ±100 - and in the case of ore, θ1: 2F+' to 80° θ2:
This is a blast furnace operating method that is characterized by maintaining the inside of the furnace in a constant state, which results in a normal gas flow distribution, by adjusting the ψα range within ±lO°. The details of its configuration are explained below.

Generally, blast furnace operation is controlled by the sedimentation state of the contents in the furnace. In particular, if the deposition angle and shape of the furnace charge, semi-soaked Jφ7, are controlled to a predetermined state, it is possible to always obtain a single charge deposition layer profile at the top of the furnace, which in turn is stable over Nagato. Based on the basic knowledge that it is effective for ensuring blast furnace operation, the following configuration was adopted.In other words, stabilization of blast furnace operation is controlled by the gas flow within the furnace. What governs this is the gas flow seen in the furnace center and the furnace f section in 1E. As shown in Figure 3, the gas flow at the center of the furnace depends on the state of charge deposition at the center.I)
In addition, the gas flow in the furnace wall is determined by the charge deposition state near the furnace wall, and furthermore, the flow of these gases is determined by the distance between the furnace inner wall and the peak, if we take an example of M-shaped charge distribution. 1
It turns out that it is also regulated by 1. So these θ
1°θ2, I researched LG and decided as follows.

In Fig. 8, 1 is the furnace wall, 2 is the charge pile, the laminated surface, and the position of the 8-crest part (distance L from the furnace wall surface) 4 is the charge layer Q pile slope on the furnace wall side. As shown, the pottery is θ2,
5 indicates the charge deposition slope on the furnace center side, and its deposition angle is set to 0.
Set to 1. There are various methods for determining the above symbols L, θ2, and θ1, but in the present invention, they are determined as follows. The method is as shown in Fig. (The angle of the slope between the rebond and point ■ is determined by drawing, and the slope deposition angle θ1 on the furnace center side is determined, and the deposition angle θ2 on the slope on the P wall side is determined. is the angle between point ■ and point ■ determined by a similar drawing.

On the other hand, the vicinity of the father point of the straight line atb regulating the charge layer deposition slopes 4 and 5 as described above was defined as the mountain part 3, and the distance from the furnace inner wall surface was defined as L.・The distance to this mountain part 3 is the straight line a, l b obtained from the above-mentioned pile angle θl and 02.
It cannot be set only by As shown in FIG. 5, the same θ1.
Even θ2 has the same size as L, and the profile shown in the furnace radial direction is also completely different depending on the difference. Therefore, in the case of unexploded 1111J, considering these circumstances, Yamabe 8
The position was specified by the father point of the a and b lines as described above. In addition, for 3g1 cases where the measurement method is Ge4, the number of measurement points is increased and statistical processing by Keiso and Iso is performed. For example, if the depth sounding device employed is a μ-wave or laser type, it is desirable to obtain the measured value using the least squares method and calculate θ1.02.

Next, the state of the charge layer f>'t j・〆7 will be shown, and at the same time, the method of setting the "chamber value" which is the target of blast furnace operation will be explained.

In general, during blast furnace operation, the gas flow in the furnace changes depending on the profile of the charge deposit layer of the raw material that has been removed from the top of the furnace, and by adjusting this, the stability of the charge descent can be stabilized.
can be achieved. Therefore, the stability of the burden descent, that is, 79771111 degrees or the wind pressure fluctuation index, and the above-mentioned total f (u value, θ').

Calculation of θ2's 1st direction (by examining the circumference 1 system by n4, force) fJ)
We calculated the θ〃and]direction. FIG. 6 shows the relationship between the slip frequency and the stacking angle 01 of the charge layer on the furnace center side, and FIG. 7 shows the relationship between the number of wind reductions and the stacking angle 01. The circle mark in the figure indicates the ore deposition angle θ1. The X mark indicates the coke deposition angle θ1, and from this figure, the slippage is small when the deposition angle θ1 of the ore in the charge is 80° or less, and this deposition angle θ1 may be 2.
If it is 0° to 80° or less, the number of wind reductions to suppress the wind pressure change pL1B is also small. If θ1 is less than 20', this means that a large amount of ore is deposited in the center of the furnace, and as the furnace becomes more aerated, the wind pressure fluctuates more and the number of wind reductions increases. It means. Also, 0 of ore
1 is greater than 30°, ore rolls on the inclined surface 4.5 of the charge layer and deposits in the center, causing instability in unloading and increasing slip. Therefore, a suitable range for stable operation with no slip and less wind pressure fluctuation is a range where the above-mentioned deposition angle θ1 is 20° to aO°.

On the other hand, when the deposition angle θ1 of coke in the charge is less than 25°, the slip frequency increases, and when it is 35° or more, the number of air reductions increases. In short, the larger the coke pile and the injection angle θ1, the more ore will flow into the center of the furnace during the next G, and the furnace condition will become unstable due to deterioration of air permeability. Become. The fact that the coke deposition angle θ1 is small means that
This means that a large amount of coke is deposited in the center, and the ore is shifted toward the furnace wall, resulting in center flow-oriented operation, which stabilizes the wind pressure, but promotes the growth of the inert zone on the furnace wall, causing slippage. Likely to happen. As explained above, the coke deposition angle θl is set to 25° to 35°.

Now, the deposition angle θ2 of the slope of the charge layer on the furnace wall side is determined by the M type (a), M type (b
) showing different aspects in the distribution. Therefore, when the sign of the deposition angle θ2 is positive, it is assumed to be M type, and when it is negative, it is assumed to be M type.

In the M-type distribution, when the coke deposition angle θ2 is large, a large amount of ore is charged toward the furnace wall, which causes deposits to form. Furthermore, in the M-type distribution, if the coke deposition angle θ2 is large, the flow of ore into the center of the furnace is promoted, and the above-mentioned wind pressure becomes unstable. In the case of ore, if the deposition angle θ2 is large in the M-type distribution, a large amount of coke will be charged to the furnace wall, resulting in excessive peripheral flow direction. This promotes coke flow and is unfavorable in terms of distribution control.

FIG. 9 shows the relationship between the accumulation angle θ2 and the number of wind pressure fluctuations (wind reduction number). As is clear from this figure, when the coke G exceeds ±10°, wind pressure fluctuations increase, and the ore also changes ±lθ.
If the temperature exceeds °, wind pressure fluctuations will increase. Therefore, the proper control of the deposition angle θ2 is ±10°, that is, within 10° whether the in-furnace contents are deposited in the M type or in the M type distribution.

Next, regarding the position of the peak 3, that is, the distance from the furnace inner wall, for example, if the distance to the peak 3 is long, it means that the ore is charged toward the center of the furnace and the wind pressure is leveled. This means that the temperature at the center of the furnace is getting worse. On the other hand, in the case of coke, the peak 8
The larger the distance 1, the easier it is for coke to enter the furnace center, resulting in excessive central flow direction and promoting the growth of an inert zone on the furnace wall. The first ()1 in the drawing shows the relationship between the distance to the mountain and the number of slips (times/day).

As can be seen from this figure, when the distance from the inner surface of the furnace wall to the peak 3 is between 0.5 and 1.6 m, the number of occurrences of block slip is small. value.

In this way, how can we control the lung intake distribution so that the MiJ results JQθl, θ2, and distance are set to the set values? 1ll
By doing so, a constant DJ state can be obtained, and stable blast furnace operation can be achieved over a long period of time with a constant gas flow distribution σ).

In addition, each control value that is the target for blast furnace operation has increased by +71S.

θノ, θ2 is fj! In order to control the amount of Pt in the furnace so that it falls within a set range such as Appropriate measures such as adjusting the G Goss dock line can be adopted. On the other hand, in the case of a bellless blast furnace, adjusting means such as the first movement angle of the turning chute or the stock line is performed by employing a chamber G.

In addition, the stock line and bell-to-be mentioned here refer to the distance from the zero point to the surface of the containing layer, with the zero point being 1m below the bottom of the bell, and if it is a bellless type, the node Lower 1 shot! ? The point 1 m below j is defined as zero, and a preset charging line from that zero point to the surface of the charging material jφ is used.

Next, let's talk about the three blast furnace operations mentioned above! An example in which all blast furnace 1 operations were carried out based on management targets and rj control values will be described below.

Contents FI 4500 m3 bell type blast furnace with charging conditions of coke base 84.3 t/ah, ore] 18
t/ch.

It was operated with a stock line of 1.2 m and a movable armor setting of O], 03. (0103 is No.]) As shown in IA, the setting of the notch of the G removable armor is (Φ~
When charging coke into the furnace when there are five points of (This is a method for controlling the distribution of

The 121st ffi shows changes over time in the JZ control values targeted during blast furnace operation. On 4/2 of the date,
The coke deposition angle θ2 on the furnace wall side became larger. Therefore, by lowering the stock line from 1.2 m to 1.3 m, coke was charged toward the furnace wall side and changed from M-type distribution to M-type distribution. As a result, θ2 became smaller and fell within the control value.

After that, the deposition angle θl on the furnace center side decreased for moss, coke, and ore. So the ore armor
By changing the notch from ■→■ and the armature notch of coke from ■→@, and charging ore and coke to the furnace wall side, the accumulation θ1 was recovered.

After that, on April 10th, the distance to the ore mountain became smaller. So I found the ore Armor Notch■→
When the ore was charged into the furnace by returning to
The magnitude of the distance has increased.

After that, -+/lS contains +11?
Jθl was too large, so by raising the stock line and charging more coke into the furnace, the deposition angle θ
] has become smaller.

-1- J'' as described above, θ1. When the blast furnace was operated with each control value of θ2 as the target, it became possible to operate the blast furnace stably over a long period of time. In this example, the stock line and movable armor settings were combined and After changing and adjusting to the specified control value.

It is possible to maintain an appropriate gas flow distribution, making stable operation of the blast furnace possible over a long period of time. On the other hand, it is possible to appropriately maintain the charge layer profile in the radial direction within the furnace by appropriately combining some of the operational actions for controlling the charge distribution. For example, the blast furnace may be operated to achieve the control value of the present invention by appropriately selecting and combining waiting conditions other than the combination of the mobile armor and the stock line as in the above embodiment.

As explained above, according to the present invention, it is possible to maintain the deposition state of the charge in the furnace in an appropriate state with little fluctuation in furnace conditions, so it is possible to ensure stable blast furnace operation over a long period of time. 7j ivy.

[Brief explanation of the drawing]

Figure 1 is the route map of the oblique profile measuring device, Figure 2 is the route map of the μ liquid type profile 1ljl+¥ device, Figure 8 is the route map of the profile showing the state of accumulation of debris in the furnace, and Figure 4 is the route map of the control system. Figure 5 is a line M showing the relationship between the immediate values θ1, θ2, and L. Figure 6 is a graph showing the relationship between the slip fineness and the accumulation angle θl. is reduced!@, a graph showing the relationship between the same number and the deposition angle θ1, s 1ffi (a) and (b) are one line showing the infiltrate distribution form [zo, Figure 9 shows the number of wind reductions and the deposition angle θ2 Figure 10 is a graph showing the relationship between the number of slips and the distance to the mountain + flX. Figure 111J is a route map showing how the armor notch operates. It is a graph of changes in each control value over time in an example operation. 1... Furnace wall, 2... Surface of the pedestal sediment layer, 3...
The position of the peak indicating the distance (J”) from the inner surface of the furnace wall, 4...
・Charge j+) on the furnace wall side:, +I! is the slope (accumulation angle θ2
), 5... Furnace center γ speed rule's sleep 11 butltb,
+Zenta [ji (estimate 1 responsibility river θ]), 611. Pell,
7... Armor Notch. Patent applicant Kawasaki'! l! ! Tetsu Co., Ltd. Figure 1 Figure 91
:(1 31'4 1st fig. 7 15 20 25 30 :35 40
・Nito Naka 曵゛Lucky 呵 Ω] 〆j)X@R'lq corner (
θf) Fig. 8 <:1) cljt, > /. 1st ri i'=-r 10th tχ1 th ] ] 1 ¥1

Claims (1)

[Claims] 1. A method for operating a blast furnace while controlling the gas flow distribution in the furnace by changing the deposition state of the charge in the blast furnace, comprising: charging the charge in the furnace radial direction; The distance from the furnace inner wall to the peak is L, the deposition angle of the charge layer deposition slope on the furnace center side is θl, and the distance of the charge layer deposition surface on the furnace wall side is When the deposition angle is 02, the values θ1 and θ2 are L: 0 for both ore and coke.
．． 5 to 1.5 m and when the charge layer is coke, θ]: 02 = ±1 at 25° to 35°
(Target gas flow distribution) (Target gas flow distribution) A blast furnace operating method characterized by maintaining a deposited state in the furnace.