JPH0211711A - Method for controlling distribution of feedstock in blast furnace - Google Patents

Abstract

PURPOSE:To uniformly feed raw material to circumferential direction in a blast furnace and to stabilize the furnace condition by controlling feeding the raw material with a swinging chute based on the result of actual monitoring of the fed material distribution to the circumferential direction in the furnace at the time of feeding the raw material with the swinging chute in top part of the blast furnace. CONSTITUTION:Iron ore and coke in fixed hoppers 2, 3 are fed into the blast furnace while swining the swinging chute 9 after passing a fixed chute 8 through gates 4, 5. In this case, based on inputs of weighers 16, 17 in the fixed hoppers 2, 3 and swung angle of the swinging chute 9, etc., the actual result monitoring of the charged material on a small bell 10 is executed and the results is expanded into Fourier series to obtain frequency distribution of segregation. Then, by dynamic-operating and working position of the swinging chute 9 so that the raw material wt. of each iron ore and coke at every few batches, regular revolution/reverse revolution ratio of the swinging chute 9 and each accumulated value of the raw material discharged wt. entirely become the constant values on the small bell 10, the charged material is uniformly distributed to the circumferential direction in the blast furnace and the furnace condition in the blast furnace is stably operated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for controlling the distribution of raw material charge in a blast furnace, and more specifically, when charging raw material into a blast furnace from the top of the blast furnace through a rotating chute, The present invention relates to a method of controlling the charge distribution so as to be constant over the circumferential direction of the blast furnace.

Conventional technology The top of the blast furnace is equipped with a chute with a rotating function for dropping and distributing the granular material into the furnace.This chute allows the material to be charged into the blast furnace and distributed uniformly in the furnace. The method is adopted. An example of an apparatus used to carry out the above method will be described with reference to FIG. 6. Although FIG. 6 shows an example of a so-called bell-type raw material charging system which is simple in operation, the same applies to a bell-less charging system. Reference numeral 1 in the figure indicates various ores (A) and coke (A), which are raw materials for blast furnaces, collected from the ore storage tank and the storage tank (not shown).
2.3 is a charging conveyor for transporting the raw materials A and B to the top of the blast furnace; 2.3 is a fixed hopper 4.5 that serves as a temporary storage area for the raw materials A and B before charging them into the blast furnace; 4.5 is the bottom of this fixed hopper; 6. A gate located at the gate for discharging raw materials by opening and closing operations;
7 is a seal valve for sealing the top gas, 8 is a fixed chute, and 9 is a rotating chute. These are small bell 10
This is an important device that is located directly above the blast furnace and is installed for the purpose of making the distribution of these raw materials uniform in the circumferential direction of the blast furnace. The swing chute 9 is driven by a hydraulic motor 11 as a power source, and the hydraulic motor 11 is rotated by the hydraulic pressure generated by a hydraulic pump 13 whose driving source is an electric motor 12. A solenoid valve unit 14 is installed in the middle of the piping to control switching of the hydraulic pump 13 between normal rotation, reverse rotation, braking, etc.

FIG. 7 shows the flow of operations in the equipment configuration around the rotating chute described above. First, the swing chute 9 is continuously driven to swing in either direction, and at the timing when the acceleration is finished and the rotation becomes approximately constant speed, the opening operation of the seal valve 6.7 and the detection of the opening operation are simultaneously performed, and the gate 4 is opened. 5 as sequential opening operation. From this, the raw material in the fixed hopper 2.3 passes through the gate 4.5 and the seal valve 6.7, and is charged onto the circumference of the small bell 10 through the fixed chute 8. The gate 4.5 is closed after a sufficient margin of time when all the raw materials in the fixed hopper 2.3 are thought to have been discharged, and the sill valve 6.7 is closed at the same time as this closing operation is detected. after that,
The rotating SUD 9 is stopped. In Fig. 7, the shaded area is
This shows the timing at which the raw material is falling onto the rotating chute 9.

The above operations are sequentially repeated as the furnace top batch progresses. Note that the rotation direction of the rotating chute 9 can be selected by operator settings, and is switched for every certain number of batches at the top of the furnace.

In the operation of the above-mentioned rotating chute 9, it has been pointed out that due to the following problems, a charging deviation occurs on the circumference of the small bell.

The position control of the rotating chute is not controlled only by sequential control mainly based on zero time management.

■Since the rotating chute is hydraulically driven, it is easily affected by changes in temperature, viscosity, and load (raw material weight), and its operating speed is not constant.

■Whether the rotating chute rotates forward (the rotating chute 9 rotates in the direction of the arrow in Figure 1) or reversely (the rotating chute 9 rotates in the opposite direction to the arrow in Figure 1) is determined by normal rotation. In reverse rotation, the charge distribution in the circumferential direction is symmetrical with respect to the start position of the rotation, so although it is an important element in controlling the circumferential charge distribution, it is left to manual management. , there are no clear control guidelines.

Due to the above problems, in the current control, the position and rotation speed of the rotating chute 9 when the material falls, that is, the small bell 1
The falling position of 0 in the circumferential direction is in an uncontrolled state, and uniform distribution control cannot be expected.

Various attempts have been made to solve this problem.

For example, there is one disclosed in Japanese Patent Application Laid-Open No. 62-63606.

This method detects the change in material discharge speed from the fixed hopper and the rotation angle of the rotating chute to grasp the actual loading performance through distribution performance monitoring, and reflects this actual value in the next control. In this control, phytback control is performed to sequentially cancel the segregation valve.
According to this method, it is possible to control the falling position of the small bell in the circumferential direction, but when segregation occurs in the charge distribution, it is difficult to find a means to eliminate the segregation by trial and error. However, there are many cases where no means of eliminating segregation can be found, making it difficult to adequately control the charge distribution.

Problems to be Solved by the Invention The present invention aims to solve these problems, and specifically, in the conventional example, when distributing and charging blast furnace raw materials into the furnace using a rotating chute, the position of the rotating chute is not controlled. Since the swing chute is hydraulically driven, it is easily affected by changes in the oil in the hydraulic pump, and the operating speed is not constant.The criteria for determining whether to swing the swing chute in the forward direction or in the reverse direction (A mouth that causes charging deviation on the circumference of the small bell due to manual control etc.)
Furthermore, it is an object of the present invention to solve the problem that a method of controlling the distribution of the blast furnace raw material charge that solves the raw material charging deviation on the circumference of the small bell has not been sufficiently established.

As a means for solving the problem, the present invention has the following advantages: When charging raw materials from a plurality of fixed hoppers into a blast furnace via a rotating chute, the present invention is capable of discharging from a weighing scale of the fixed hoppers and discharging from a rotating chute. Based on inputs such as the rotation angle of the blast furnace, actual monitoring of the charge distribution in the circumferential direction inside the blast furnace is performed, and based on this result, the cumulative values of the raw material weight and discharge order for each batch of ore and coke are calculated. Based on a mathematical model of segregation expressed in a Fourier series so as to maintain a constant value over the entire rotation angle, the discharge timing for the next charge is dynamically calculated step by step, and raw materials are charged based on the results of this calculation. shall be.

Therefore, the structure of these means and their operation will be explained in more detail as follows.

The present invention operates based on inputs such as the weight scale of the fixed hopper 2.3 of raw materials A and B and the turning angle of the turning chute 9.
By monitoring the performance of the charge distribution on 0 and expanding the results into a Fourier series to obtain the frequency components of segregation, we can calculate the raw material weight, forward/reverse rotation ratio, and raw material weight for each batch of ore and coke. Each cumulative value in the ejection order is the total turning angle,
That is, the position (start point) of the rotating chute 9 at the start of discharging the material to be charged next time is dynamically calculated so that it becomes a constant value over the entire circumference of the small bell 10,
The blast furnace raw material is charged according to this method, and this method was completely unknown in the past.This method allows for obtaining an appropriate distribution of the burden material and ensuring stable operation of the blast furnace. A method for controlling charge distribution is provided.

Hereinafter, the present invention will be described in detail with reference to the drawings.

In addition, FIG. 1 is a schematic cross-sectional view including a partial block diagram of an example of a blast furnace raw material charging apparatus used when carrying out the method of the present invention, and FIG. 2 shows a circumferential direction charge distribution. Fig. 3 is a graph showing the circumferential charge distribution with the diagram in Fig. 2 taken as a periodic function, and Fig. 4 is a graph in which the starting point is shifted by 72° from the starting point of 0°. Figure 5 is a graph showing the change in the circumferential distribution of charge deposited in the blast furnace during five charging times, and Figure 5 shows the change in the circumferential distribution of charge deposited in the blast furnace during the winter cropping shown in Figure 4. FIG. 6 is an explanatory diagram showing an overview of the distribution in the furnace using a conventional rotating chute; FIG. FIG. 3 is a flow diagram of peripheral device operations.

1 is the charging conveyor, 2.3 is the fixed hopper A, B, 4
．． 5 is gate A, B, 6.7 is seal valve A, B, 8
is a fixed chute, 9 is a rotating chute, 10 is a small bell, 1
1 is a hydraulic motor, 12 is an electric motor, 13 is a hydraulic pump, 1
4 is an electromagnetic unit, 15 is a distribution performance monitoring calculation device, 16.17 is a weighing scale A, B, 18 is a position detector, 19 is a furnace top sequence device, 20 is a printer, 21 is a distribution control calculation device, 22 is a gate The control device is shown.

The configuration of the peripheral equipment of the rotating chute 9 of the raw material charging device shown in FIG. 1 is such that the following equipment is added to the equipment configuration of the conventional example shown in FIG.

In this embodiment, the same equipment as in the conventional example is omitted from the reference numerals shown in FIG. 6, and redundant explanation will be omitted. Reference numeral 15 in the figure is based on the weight signal from the weight scales 16 and 17 provided in the fixed hopper 2 for raw material A and the fixed hopper 3 for raw material B, and the rotation angle signal from the position detectors 18 of the rotation shoes 1 to 9. This is a distribution performance monitoring calculation device that assumes the charge distribution on the small bell 10. The device also receives a signal from the existing top charging sequence controller 19 to distinguish the material deposited in the stationary hopper 2.3, ie, ore or coke. The furnace top charging sequence control device 19 tracks the flow of a series of raw materials from the ore storage tank or the storage tank, and distinguishes between raw materials when charging the raw materials onto the small bell 10 with the rotating chute 9 between the fixed hopper and the fixed hopper. With the tracking results in 2.3,
This is to be taken into the distribution performance monitoring calculation device 15. The distribution control arithmetic unit 21 captures the actual results of the actual loading situation at the front stage, expands the results into a Fourier series using fast Fourier transform processing, obtains the frequency components of segregation, and sends the results to the printer 20 from the front stage. The captured distribution performance monitoring performance is output together with the /mW processing result in the i-device 15. Then, the frequency components of segregation, the total cumulative value of the weight of ore for each of the latest batches, and the raw material weight for each coke are determined by the total rotation angle,
That is, the star 1-point for the next charging is dynamically calculated one by one so that it becomes a constant value over the entire circumference of the small bell 10. Reference numeral 22 in the figure is a gate control device that controls the opening operation of the seal valve 6.7 and subsequently the gate 4.5 based on the previous command.

As is clear from the above configuration, the present invention is based on the features described below.

That is, the present invention expresses the charge distribution in the circumferential direction as a 7-rework series, and calculates the optimal starting point of the rotating chute 9 from the magnitude of each frequency component of the segregation, thereby dynamically realizing the following characteristics: The idea is to do so.

The present invention will be further explained in detail below.

First, the processing method in the distribution performance monitoring calculation device 15 will be described. Input signals of changes in the weight of the individual weight scales 16,17h, etc. of each of the fixed hoppers 2 and 3, and changes in the classification of raw materials (ore, coke) from the furnace top charging sequence control device 19, The relationship between the rotation angle and the amount of raw material charged is derived by making a temporal correspondence with a change in the rotation angle signal from the position detector 18 of the rotation tip 9, which is one input signal. The amount of charged raw materials is divided into four categories: ore, coke, the amount discharged from the fixed hopper 2 (raw material A), and the amount discharged from the fixed hopper 3 (raw material B).

Next, details of the processing method in the distribution control calculation device 21 will be described.

A diagram showing the circumferential charge distribution captured by the distribution performance monitoring calculation device 15 (a diagram showing the relationship between the turning angle of the rotating sudo and the charge weight) is shown in the form shown in Fig. 2. However, by considering this charge distribution as a periodic function with a period of 360 degrees in mathematical terms as shown in the diagram in Figure 3, the charge distribution can be expressed as a Fourier series, It becomes possible to mathematically describe the deviation in the circumferential direction of the charge distribution (this Fourier series is described in the Industrial Basic Exercises Series I "Furier Analysis" published by Ikita Publishing, etc.). Since the temperature and viscosity of the hydraulic pump can be considered to be in the same state within a short time, the rotation speed of the rotation chute 9 is not affected by changes in the temperature and viscosity of the hydraulic pump during the charging of several batches of raw material. . In addition, fixed hopper 2.3
The temporal change in the weight of is constant if the amount and properties of each raw material charged into the fixed hopper 2.3 are the same and the gate opening degree is the same. Therefore, when the amount of raw material charged into the fixed hopper 2.3 and the raw material properties are the same, the distribution of the charged material in the circumferential direction charged per batch is (1 ) and (1)'.

f(θ, θ' 1=ao+Σ(ak −cos(k ・
(θ−θ′)) +1 +bksin(k(θ−θ′))) −・・−=(
1)=ao+ΣCk (Sin(- to -θ'+γk)・C08(k・θ)+cos(-k・θ′+
7kl −5in(k−θ))・・・・・・・・・(1
)' However, θ: Blast furnace circumferential direction angle f (θ, θ') Circumferential charge distribution when charging at Ni start point θ' degrees -TAN-1 ak Ck-Product T 〒1F In equations (1) and (1)', each term other than ao is involved in segregation in the circumferential direction. If the raw material is charged once by shifting the starting point ψ (j is a relatively prime positive integer), the circumferential raw material distribution F deposited in the blast furnace is
(θ, L, j) is determined by the following equation (2).

F (θ, L, J) = Lao + Σi −ci・4
Hsin (L-k・θ1γ6.k)...(2)
In equation (2), the frequency component of segregation is 0 for terms that are not integral multiples of L.

Changes in the circumferential distribution of raw materials deposited in the blast furnace due to charging (relationship between rotation angle and raw material weight), segregation of the contents distribution in the furnace, and changes in frequency components (ak2 + bk2) for each charging batch. Calculate and show the results in Figures 4 and 5, respectively.
The figure shows the printer output results.

The distribution calculation control I calculation unit 21 calculates the frequency component of segregation using equation (1), calculates the maximum frequency value kmax of the frequency component without adversely affecting the blast furnace operation, and performs control to eliminate the problem for each fixed hopper 2.3. This is also done for each coke and ore. The calculation of the shift angle to shift 1 is performed for each charging batch, and if the newly calculated shift angle differs from the currently used shift angle by more than a certain value, it is changed, and the circumferential distribution on some small bells is changed. Assume that disturbances have no effect on control. The maximum frequency value kmax is calculated by calculating F(θ, m, j) for each cumulative value of ore, raw material weight for each coke, and raw material discharge order, and then calculating the value in L where the total segregation Σp is equal to or higher than the standard level □. be the maximum value of

In addition, after determining J, calculate the cumulative deviation "(θ, θ') up to kmax + 1 charge for each J using equations (3) and (4).
Calculate with n = km from n = 1 for km
Adopt j that minimizes the segregation 5〆 during charging up to ax +1 times.

ΣF(θ, θ' 1=n-ao +Σ(8K・S
II′1θ+BK−CO3θ)−(3), and the gate control device 22 controls the frequency component of the segregation of the charge distribution in the circumferential direction in the furnace below kmax after (kmax+1) charging times. This is a power control circuit that specifically opens the seal valve 6.7 and subsequently the gate 4.5 based on commands from the control Il calculation device 21.

Note that the distribution performance monitoring calculation device 15 and the distribution control zero calculation device 21 are configured to be processed within the same microcomputer.

According to the above-mentioned embodiment, the distribution of the blast furnace raw material charge in the circumferential direction can be automatically controlled to the optimum distribution for the blast furnace operation.

<Effects of the Invention> As explained above, the present invention enables the discharge of the fixed hopper from the weighing scale, the turning angle of the turning chute, etc. when charging raw materials from a plurality of fixed hoppers into the blast furnace via the turning chute. Based on this input, we perform actual monitoring of the charge distribution in the circumferential direction inside the blast furnace, and based on this result, we calculate the cumulative values of the raw material weight and discharge order for each batch of ore and coke over the entire rotation angle. Based on a mathematical model of segregation expressed in a Fourier series so as to maintain a constant value, the discharge timing for the next charge is dynamically calculated step by step, and the material is charged based on the results of this calculation. be.

In the conventional example, when blast furnace raw material is distributed and charged inside the furnace using a rotating chute, the blast furnace raw material charging management is not carried out sufficiently, so the blast furnace raw material charge distribution causes charging deviation on the small bell circumference, and this The current situation is that no effective or perfect solution has been found.

Therefore, the present invention has a major feature in that it takes measures to reliably grasp this deviation and dynamically reflect it in the next control. Highly effective in preventing segregation,
Therefore, a proper charge distribution can always be obtained, and
Smooth raw material charging can be performed and stable blast furnace operation can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view including a partial block diagram of an example of a blast furnace raw material charging apparatus used in carrying out the method of the present invention, FIG. 2 is a graph showing the circumferential charge distribution, and FIG. The figure is the second
A graph showing the circumferential charge distribution considering the diagram in the figure as a periodic function. Figure 4 shows the starting point shifted by 72° from the starting point of 0°. Figure 5 is a graph showing the changes in the distribution of the circumferential raw material deposited in the blast furnace for each charge. FIG. 6 is an explanatory diagram showing an overview of the distribution in the furnace due to the conventional rotating chute, and FIG. 7 is a flowchart of equipment operations around the conventional rotating chute. Code 1...Charging conveyor 2.3...
Fixed hopper 4.5...Gate 6.7...
... Seal valve 8 ... Fixed chute 9 ...
...Swivel shoe 1-10 ...Small bell
11... Hydraulic motor 12... Electric motor 13... Hydraulic pump 14...
Solenoid valve unit 15...Distribution performance monitoring calculation device 16.
17... Weight scale A 18... Position detector 19... Furnace top sequence equipment 20... Printer 21... Distribution side t [l Arithmetic unit 22...
・Gated tIl device

Claims (1)

[Claims] 1) When charging raw materials into the blast furnace from multiple fixed hoppers via the rotating chute, charging in the circumferential direction inside the blast furnace based on inputs such as discharge from the weight scale of the fixed hoppers and the rotation angle of the rotating chute. Based on the results, the cumulative values of each batch of ore, raw material weight for each coke, and discharge order are expressed in a Fourier series so that they remain constant over the entire rotation angle. A method for controlling the distribution of raw material charge in a blast furnace, characterized in that the discharge timing of the next charge is dynamically calculated based on a mathematical model of segregation, and the raw material is charged based on the result of this calculation.