JPH0873908A - Apparatus for controlling grain size of charging material in bell-less blast furnace - Google Patents

Abstract

PURPOSE: To provide a control apparatus for the grain size of charging material in a vertical two stage type bell-less blast furnace, by which the grain diameter of coke charged into a center part of the blast furnace can be controlled in a high precision. CONSTITUTION: This control apparatus is provided with an ITV 31 for picking up the image of the coke on a charging conveyor 20, a picture processor 30 for obtaining the average grain diameter of the coke for executing a Fourier transform of the picture signal from the ITV 31, a grain size control grizzly 40 consisting of an upper vibrating comb composed of plural vibrating comb units inclined so as to line up below a coke bin and formed rougher toward the downstream side and a lower vibrating comb arranged along the upper vibrating comb below it and move-controlled according to the output of the picture processor 30, the grain diameter of the coke charged into the center of the blast furnace is kept within a prescribed range with the lapse of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle size control apparatus for charged raw materials in a bellless blast furnace, and more particularly to vertical 2 which has a poor charging capacity, in which the material discharge particle size characteristics are large at the beginning of discharge and the gas flow in the central part tends to be strong. Controlling the particle size of charging coke in a staged bellless blast furnace.

[0002]

2. Description of the Related Art In order to operate a blast furnace in a stable and efficient manner, it is important to properly control the gas flow distribution that rises in the furnace and to reduce the gas permeability of the furnace while effectively utilizing the reducing gas. Is. For this purpose, the lump state, the cohesive zone,
It is important to improve the air permeability of the furnace core, which enables the operation of high output ratio and the large use of inferior raw materials.

In the method of charging the raw material into the blast furnace, generally, ore and coke are charged alternately. As a method for reducing the air permeability at the time of charging coke, the bell blast furnace is disclosed in Japanese Examined Patent Publication No. Sho 64-9373 in Japanese Utility Model Sho 61.
A center charging method of coke using a chute of Japanese Patent No. 42896 has been proposed. For the bellless blast furnace,
JP-A-3-232912, JP-A-3-23291
There is a charging method proposed in Japanese Patent Laid-Open No. 3 and Japanese Patent Laid-Open No. 4-6204.

The charging method proposed in Japanese Examined Patent Publication (Kokoku) No. 64-9373 mainly describes the bell blast furnace, and the coke at each charge is time-sequentially divided into at least two series, and a total charging coke is provided. Most of the charge to cover the entire ore layer, and 8 to 1.5 of the remaining charge.
It is characterized by charging% to the center. JP-A-3
In Japanese Patent No. 232912, in the bellless blast furnace,
15% to 20% with normal coke to ensure air permeability
There is a statement that if the coke is charged into the center of the furnace, it has the effect of reducing the fuel ratio. In this publication, the difference from the former invention (Japanese Patent Publication No. 64-9373) is due to the difference in discharge behavior of raw materials from the bellless blast furnace and the hopper in the bell blast furnace. Since the rate of material discharge from the hopper is small, it is difficult to secure a central flow because the collapse of the coke layer in the lower part to the center of the ore is small when charging the ore, especially when the surface of the charge is flat. There is a statement that there is a large tendency that a larger amount of coke than in the Bell blast furnace needs to be charged in the center.

In Japanese Patent Laid-Open No. 3-232913, if high-quality coke (CSR + 15, particle size + 20 mm) is charged in the central portion, it is not necessary to charge every time, but it is possible to charge the core once every 4 to 6 charges. There is a description that charging is also effective.
Japanese Unexamined Patent Publication (Kokai) No. 4-6204 discloses a method in which coke center charging is performed by a bellless charging device using three or more hoppers, and the coke has two kinds of particle diameters (central coke-D / scattering caulk-). It is characterized in that the central coke is charged into the center of the furnace immediately before or after the sparged coke is charged in the radial direction, and then the raw material in which ore is mixed with the coke is charged. . It is reported that by carrying out this method, the permeability of the molten zone is improved and the operation is stable. Also, the particle size of the coke for central charging
It is described that the effect is further improved by improving the quality. Further, as a measure against the reduction of air permeability during ore charging, a method of dividing the particle size into two types and separating and charging in the radial direction of the blast furnace is implemented. Especially, in order to reduce the hot metal cost, recently, small block sintering of 1 to 3 mm is also used, and normal block sintering (10 mm to 20 mm
mm) and is charged into the peripheral part of the blast furnace. When a large amount of inferior raw material is used in the above-mentioned conventional technology under the operation of a high tap ratio, generally, high quality large lump coke is supplied to the center part and small lump sintering is efficiently installed in the peripheral part. It is considered desirable to enter.

[0006]

However, when the central gas flow of the blast furnace is secured by the above-mentioned charging method by the normal coke hopper equipment and the vertical two-stage bellless blast furnace having a poor charging capacity, the following results are obtained. There is a problem. (1) JP-A-62-290809 and JP-A-H3-
In Japanese Patent No. 232913 and Japanese Patent Laid-Open No. 4-6204, it is stated that a better operating result can be obtained by mainly charging high-quality coke having good air permeability. Regarding the bellless blast furnace, the coke is not charged into the central portion of the coke even if the chute shown in Japanese Utility Model Publication No. 61-42896 is not used, as disclosed in JP-A-3-232912, JP-A-3-232913, and JP-A-3-232913. Kaihei 4-6
As described in Japanese Patent No. 204, the charging can be performed by setting the tilt angle of the distribution chute to a predetermined angle. However, these inventions do not disclose specific specifications of high-quality coke having good air permeability and a supply method thereof.

Generally, in order to secure air permeability, high quality (high strength, low productivity) coke having a large particle size is required, but the coke flow size discharged from the coke oven varies. Considering that there are time-series fluctuations, large grain size segregation occurs in the coke hopper on the blast furnace side. Also, considering that the amount of coke used for central charging is small, it is possible to charge coke with a larger particle size than usual by only installing a grizzly grain with a large knot, but a stable large particle size is installed. It is impossible to enter. In addition, cold strength (DI 15/30/150/1
5) There is hot strength (CSR), but the specifications of each of the normal coke and the central coke are unclear, and it is necessary to clarify them quantitatively.

(2) Regarding the charging into the center portion of the coast, even if the chute shown in JP-B-61-42896 is not used, JP-A-3-232912 and JP-A-3-2912
It is possible to insert the distribution chute by setting the tilt angle of the distribution chute to a predetermined angle, as in Japanese Patent No. 232913 and Japanese Patent Application Laid-Open No. 4-6204. However, in a vertical two-stage hopper with inferior charging capacity, charging high quality large coke at the center with small lump sintering at the periphery every charge is aside from reducing production with ample capacity. However, this method is impossible under high-deposit iron operation. Currently, the number of blast furnaces is centralized, and in general, large-scale blast furnaces require a tapping amount of about 10,000 T / D. In addition, pulverized coal injection is also common due to lower raw material costs, and at present, the pulverized coal ratio is 80 to 100 kg / T. The layer thickness is also determined by the amount of coke charged at one time. Considering the appropriate range of the layer thickness, the charging frequency is 15
It will be necessary about 0 times. Japanese Patent Laid-Open No. 4-6204 discloses
The charging capacity of the 3 parallel hopper type bellless blast furnace is described, but the charging capacity in the case of 4 dump 1 charge is 170.
It is possible to charge CH (charge) every time and center charge of coke. However, in the case of the vertical two-stage hopper, which has a charging capacity of only 117 times in the case of 4 dumps and 1 charge, it was impossible to charge each CH at the center of the coke.

The present invention has been made in view of such a situation, and is capable of controlling the particle size of coke charged in the central portion of a vertical two-stage bellless blast furnace with high accuracy. An object of the present invention is to provide a particle size control device for charging raw materials in a blast furnace.

[0010]

A particle size control apparatus for a charging raw material in a bellless blast furnace according to the present invention is an image pickup means for picking up an image of coke on a charging belt conveyor and a Fourier transform of an image signal from the image pickup means. An image processing means for obtaining the average particle size of the coke, an upper vibrating comb composed of a plurality of vibrating comb units which are arranged in a line below the coke bin in a line and inclined, and which are formed roughly toward the downstream side, and an upper vibrating comb Has a particle size control grizzly which is arranged along the upper vibrating comb and whose movement is controlled according to the output of the image processing means, and the grain size of the coke charged in the center of the blast furnace with time. Keep within a predetermined range.

[0011]

In the present invention, when the coke is charged into the central portion of the blast furnace, the coke on the charging belt conveyor is picked up by the image pickup means to obtain an image signal. The image processing means Fourier transforms the image signal from the imaging means to obtain the average particle size of the coke. A signal corresponding to the average particle size is supplied to the lower vibrating comb, and the lower vibrating comb is controlled to move back and forth according to the average particle size. Therefore, the coke that has been classified and dropped by the upper vibrating comb is further classified by the lower vibrating comb, and only coke having a desired particle size is selected, which is transported and charged into the central portion of the blast furnace. Therefore, maintaining the particle size of the coke in the center of the blast furnace within a predetermined range over time,
When charging a large lump of coke into the center, it is possible to reduce the variation in the particle size of the coke, and the air permeability of the center of the blast furnace is the same as that of the conventional coke poppan equipment and the vertical two-stage bellless blast furnace. It is possible to secure enough even in.

[0012]

FIG. 1 is a block diagram showing the structure of a particle size control apparatus for charging raw materials in a bellless blast furnace according to an embodiment of the present invention. The raw material (coke) charged in the vertical two-stage bellless blast furnace 10 is conveyed by the belt conveyor 20, and the IT of the image processing apparatus 20 is in the middle of the conveyance.
The particle size is measured by imaging with V21. The particle size control grizzly 40 is controlled based on the measured particle size, and the particle size of the coke charged into the blast furnace 10 is adjusted. By adjusting the particle size of the coke in this way, the particle size of the coke charged into the center of the blast furnace becomes stable.

FIG. 2 is a block diagram showing the processing steps in the image processing apparatus 30. After the image signal is obtained by ITV31 (S31), it is binarized (S3).
2). Then, the unevenness of brightness is removed and Fourier transform is performed (S33), and the grain size index is obtained based on the frequency of the maximum power (S34). The average particle size is determined based on this particle size index (S35). On the other hand, the particle size is actually measured by sampling (S36), and the proportional constant at the time of calculating the average particle size is calibrated by the measured value. In order to measure this measurement online, a system for determining whether or not coke is loaded on the belt conveyor 20 is also incorporated. In addition,
Details of the image processing apparatus 20 are described in Japanese Patent Application Laid-Open No. 63-290943.

FIG. 3 is a characteristic diagram showing the relationship between the particle size index calculated above and the actual average particle size. As is clear from the figure, there is a linear correlation between the two, and it can be seen that the calculated particle size index is useful.

FIG. 4 is a schematic diagram showing the structure of the particle size control grizzly 40. Below the hopper gate 42 of the coke hopper 41, an upper vibrating comb 43 and a lower vibrating comb 44 are arranged. The upper vibrating comb 43 is composed of four or more grizzlies having different knot ranges, and the grizzlies having large knots are arranged in order from the upstream side. Lower vibrating comb 4
4 is arranged with grizzlies having finer nodes than the upper vibrating comb 43 which is movable in the flow direction, and the stroke cylinder 46 while vibrating the grizzlies by the vibrating device 45.
The particle size can be controlled by moving it back and forth. The amount of movement before and after that is adjusted according to the above-mentioned raw material particle size.

FIG. 5 shows 27/32, 37 on the upper vibrating comb 43.
It is a characteristic view which shows the test result at the time of installing a / 53, 42/58, 52/68 mm grizzly, and installing a 25/35 mm grizzly in the lower stage vibration comb 44. In this test result, the particle size control range is 30 mm to 60 mm.
mm.

By the way, the vertical two-stage bellless blast furnace is superior to the parallel type hopper in the circumferential balance characteristic of the distribution of the charged material, but is inferior in the charging ability. A method for efficiently carrying out the above control method will be described below so that cost can be reduced while maintaining high iron ratio operation when raw materials are charged in such a vertical two-stage bellless blast furnace. . In a vertical two-stage bellless blast furnace with inferior charging capacity, large amounts of coke (+10 mm of normal mass) and normal mass (45 mm)
〜55 mm) ・ Medium lump (15 mm to 25 mm) divided into three types. Sintered ore is usually lump (10 mm to 20 m)
m) ・ Divided into small pieces (1 mm to 3 mm), and the charging method is as follows. 1 charge CC (normal lump) ↓ C (large lump) ↓ OO (normal) ↓ 2 charge CC (normal lump) ↓ OO (normal + medium lump coke) ↓ Os (small lump) C (large lump) ↓ for furnace In the central part, Os (small lump) ↓ is charged in the peripheral part, and medium lump coke is mixed with ore and charged into the furnace at the latter stage of discharge, so that it is retained in the core of the furnace. To enter. For C (large block) ↓, by using the particle size control grizzly 40 described above,
A coke with a particle size 10 to 20 mm larger than that of a normal agglomerate and less variation is obtained. By mixing a medium agglomerate causk into the ore of the charge that has not been centrally charged, deterioration of coke due to solution loss is preferentially medium. Since the coke for central charging can be prevented from being deteriorated because it occurs in the lump coke, when the coke in which the grain size is controlled to be large by the control device of FIG. 1 is used, the central charging can be performed once every two charges. 8% to 15% of the total weight of coke in the charge
With the addition of, the breathability is better than when using normal uncontrolled coke.

FIG. 6 is a tracer coke in which the grain size is controlled to be large by the control device of FIG. 1 (normal mass: +10 mm).
It is a characteristic view which shows the sampling data of the furnace core sonde when 10% of the whole is used in the central part. 2C from this figure
It can be seen that the coke inserted in the central portion occupies 60 to 80% of the entire furnace core due to the preferential solution loss of the medium-sized caustic even if the charging amount is only about 10% once per H. From this, it is clear that the control of the particle size by the control device of FIG. 1 and the use of the medium coke make a great contribution to the improvement of the air permeability.

Next, a method for improving the quality of the coke in the central portion so as to use a large amount of inferior raw materials such as small-grain Sr and low-grade coke will be described. Coke quality is usually cold strength (D1 30/15/150/1
5), hot strength (CSR) and other indexes are used for management.
These can be basically controlled by coke operation (furnace temperature) and coal blending. For cold strength, reflectivity,
It is controlled by blending control based on the characteristics of individual coal such as fluidity and toner quality, and dry distillation time in a coke oven. Regarding the hot strength (CSR), the reactivity of the coke (CRI) and the temperature of the coke oven are arranged. C
RI is organized according to the alkali content of the blended coal and the dispersion state of the reflectance. The relationship between these DI and CSR coke quality control indexes and blast furnace operation was clarified by a coke behavior survey in the blast furnace.

FIG. 7 is a characteristic diagram showing the influence of CSR on the operation of the blast furnace. It can be seen that at the time of insertion, the coke with high CSR has a larger furnace core coke grain size and better operation performance. That is, it is considered that the effect of using high CSR coke is due to the improvement of the air permeability in the lower part of the furnace. From these, even if the quality of the whole coke is not improved, by improving the quality of the central coke (up particle size, CSR, DI)
Due to the above reason, even if it is inserted once in 2CH, 60-80% of the furnace core coke is replaced with high-quality coke, so from the viewpoint of the furnace lower air permeability, the coke quality in the peripheral part is reduced, or A large amount of small particles Sr can be used.

Next, details of the case where the control device of FIG. 1 is implemented in a vertical two-stage belt blast furnace will be described. For coke, the raw material is a large lump (+10 mm of normal lump).
Normal block (45 mm to 55 mm), medium block (15 mm to 25 mm)
mm), and for sintering, a normal mass (10
(mm to 20 mm) and small pieces (1 to 3 mm), and insert the following. 1 charge CC (normal mass) ↓ C (large mass) ↓ OO (normal) ↓ 2 charge CC (normal mass) ↓ OO (normal + medium mass coke) ↓ Os (small mass)

FIG. 8 is an explanatory diagram showing the deposition behavior of the insert distribution in the furnace at that time. As shown in the figure, the first charge CC (normal mass) is charged so that the insertion surface has a reproducible flat distribution. For the next C (large block), the coke controlled to +10 mm of a normal block is charged into the center by using the image processing device 30 and the control grizzly 40. Further, OO (normal) is also charged so that its charging surface is flat. Charge CC (normal mass) of the second charge so that the charging surface is flat. The next OO (normal + medium coke) is also charged so that the insertion surface is flat. The medium-sized coke is mixed and cut out from the raw material storage hopper so that the medium-sized coke is discharged in the latter stage of discharge from the lower bunker, and the medium-sized coke is retained in the center of the furnace. Deterioration of caustic due to solution loss occurs preferentially to this medium-sized coke, and its low reactivity prevents deterioration of the center charging coke. In addition, the last Os (small mass) is charged into the periphery so that the charging surface is flat as a whole.

Next, a vertical two-stage bellless blast furnace 110
An example performed under 00T / D operation will be described. The charging method and charging amount are shown below. 1 charge CC (normal lump) ↓ C (large lump) ↓ OO (normal) ↓ 33.2T 3.7T 147.7T 2 charge CC (normal lump) ↓ OO (normal + medium lump coke) ↓ Os (small lump) 36.9T 127.7T (+ medium block 3.2T) 20.0T Here, the normal coke is 45 to 55 mm, the center charging coke is +10 mm, and the medium block coke is 15 to 25 mm.
I used the one. Usually, the one having a diameter of 10 mm to 20 mm and the one having a small particle size of 1 to 3 mm were used. By using the image processing device 30 and the particle size control grizzly 40, the change in the particle size of the coke charged in the central part was ± 2 mm. 1
At 1000 T / D, the required number of times of charging is 135 times, and the charging capacity of the above-mentioned 3 dumps / one charge is 150 times. By introducing this example, ventilation is possible even in a vertical two-stage bellless blast furnace. Enables central charging of coke with good performance.

FIG. 9 is a characteristic diagram of the coke particle size showing the control result in the above case. In this example, the change in particle diameter of the coke charged in the center was ± 2 mm. When the amount of tapping is 1100 T / D, the required number of times of charging is 135 times, and the charging capacity of the above-mentioned 3 dumps / one charge is 150 times, and the charging method of this embodiment is applied. As a result, even in a vertical two-stage bellless blast furnace, central charging of coke with good air permeability is possible.

FIG. 10 is a characteristic diagram showing the effect when the quality of the central coke is changed, and shows the relationship between the CSR and the small grain Sr compounding ratio. If the CSR deteriorates, the air permeability in the blast furnace cannot be ensured, and the furnace condition becomes unstable, making it impossible to use small-grain sintered ore. However, only the center coke C
When SR is set to +10, the amount of small-grain sinter used can be used at the same level as when all the cokes have high CSR. However,
No further effect can be expected even if it is raised more.

FIG. 11 is a diagram quantitatively showing the effect by dividing the effect into coke quality and the amount of small-grain sinter used.

Next, various charging methods up to the present invention and their effects will be described. Case 1: CC (normal lump) ↓ OO (normal lump) Case 2: CC (normal lump) ↓ C (normal lump) ↓ OO (normal lump) / CC (normal lump) ↓ OO (normal lump) ↓ Os (small Lump) Case 3: CC (normal lump) ↓ C (large lump) ↓ OO (normal lump) / CC (normal lump) ↓ OO (normal lump + medium lump coke) ↓ Os (small lump) Case 4 ^* : CC ( Normal lump) ↓ C (large lump) ↓ OO (normal lump) / CC (normal lump) ↓ OO (normal lump + medium lump coke) ↓ Os (small lump) ( ^* Application of image processing device + particle size control grizzly)

In Case 1, in order to maintain the air permeability, it was necessary to maintain the normal lump coke at 55 mm and the normal lump sintering at 15 mm in order to secure the tapping amount of 1100 T / D. In Case 2, small particle sintering with a particle size of 2 mm was possible up to 1%. In case 3, normal mass sintering was possible to 12 mm and small grain sintering was possible to 2%. In the case 4 in which the image processing device 30 and the particle size control grease 40 are introduced, it is possible to mix the normal lump coke to 50 mm, the normal lump sinter to 12 mm, and the small grain sinter to 6.7% (20 T in Os). It is also possible to reduce the drum strength of normal lump coke by 0.03.

[0029]

As described above, according to the present invention, the coke is imaged, the average particle size is obtained based on the image signal, and the lower vibrating comb is moved back and forth according to the average particle size. The coke was sifted and selected, and only the coke with the desired particle size was selected and charged into the center of the blast furnace, so the particle size of the coke in the center of the blast furnace is within a predetermined range over time. The coke can be supplied to the center part with a small variation in the particle size of large coke, and the air permeability of the center part of the blast furnace is sufficiently secured even with the conventional coke popper equipment and the vertical two-stage bellless blast furnace. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a charging raw material particle size control device in a bellless blast furnace according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a processing process in the image processing apparatus of FIG.

FIG. 3 is a characteristic diagram showing a relationship between a particle size index calculated by the image processing apparatus of FIG. 1 and an actual particle size.

FIG. 4 is a schematic diagram showing the configuration of the particle size control grizzly of FIG.

5 is a characteristic diagram showing a test result of the particle size control grizzly of FIG. 1. FIG.

FIG. 6 is a characteristic diagram showing sampling data of a reactor core sonde in the embodiment of FIG.

FIG. 7 is a characteristic diagram showing the effect of CSR on blast furnace operation.

FIG. 8 is an explanatory diagram showing the deposition behavior of the charging distribution in the furnace in the embodiment of FIG.

9 is a characteristic diagram of coke particle diameter showing the control result in the example of FIG. 1. FIG.

FIG. 10 is a characteristic diagram showing an effect when the quality of the central coke is changed.

FIG. 11 is a diagram quantitatively showing the effect of FIG. 10 by dividing it into coke quality and the amount of small-grain sinter used.

Claims (1)

[Claims] 1. An image pickup unit for picking up an image of coke on a charging belt conveyor, an image processing unit for Fourier-transforming an image signal from the image pickup unit to obtain an average particle size of the coke, and a line of a line below the coke bin for inclination. And an upper vibrating comb composed of a plurality of vibrating comb units that are roughly formed toward the downstream side, and arranged below the upper vibrating comb and along the upper vibrating comb, depending on the output of the image processing means. Charging in a bellless blast furnace, characterized in that it has a particle size control grizzly consisting of a lower-stage vibrating comb that is controlled to move, and maintains the particle size of the coke charged in the center of the blast furnace within a predetermined range with time. Raw material particle size control device.