JPS5923807A - Charging method of raw material into blast furnace - Google Patents

Abstract

PURPOSE:To charge effectively raw materials into a blast furnace by detecting beforehand the average grain sizes of the raw materials from the start until the end of discharging of the raw materials from the inside of a lower top hopper with lapse of time and controlling the tilting angle of a swiveling chute in accordance with the same. CONSTITUTION:Raw materials are charged through an upper top hopper 5 into a lower top hopper 4. The kinds of the raw materials and the amt. and average grain sizes thereof are inputted into a setter for raw material conditions prior to charging of the raw materials into a blast furnace 1, and the patterns at each opening of a gate valve 7A with respect to the raw materials having the same averge grain size is beforehand inputted to a control device. When the valve 7A is opened at a prescribed opening, the change in the average grain sizes of the descending raw materials with lapse of time is known from the time elapsed since the first descending of the raw materials, from which the change in the average grain size with time is predicted. Therefore, if the angle of inclination of a swiveling chute 3 is controlled in accordance with the change in the average grain size with time, the raw materials are charged into the blast furnace in the way as to satisfy in the preset operation conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for charging raw materials into a blast furnace, and more particularly, the present invention relates to a method for charging raw materials into a blast furnace. This invention relates to a method for charging raw materials into a blast furnace, which aims to eliminate particle size segregation and control the raw material particle size in the radial direction.

There are two types of top charging equipment for blast furnaces: a quiz type with a bell (hereinafter referred to as a bell-type blast furnace) and a quiz type without a bell (hereinafter referred to as a bell-less type blast furnace) with a rotating seat inside the furnace. They can be roughly divided into two types: the former are quizzes that have been widely used in the past, and the latter are quizzes that have been widely adopted since then.
The technology disclosed in Japanese Patent No. 4082 is relatively new, and improvements regarding this technology are being actively made.

The advantages of the bellless blast furnace are that the charging position can be set arbitrarily when charging raw materials into the furnace, and that the furnace top charging device is compact and economical.

That is, the first advantage mentioned is that the raw material can be charged at any desired point on the charging plane by rotating the rotating chute provided in the furnace and adjusting its tilt angle. The economical aspect mentioned below means that the larger the bell type blast furnace becomes, the more difficult it is to manufacture and replace the bell, and the higher the height of the blast furnace, the higher the construction cost. On the other hand, since the pellet-less blast furnace does not have a bell, there are no restrictions or difficulties in manufacturing or replacing the bell, and the 9-furnace top charging device can be made into a concrete. This has the economical advantage that the furnace height can be lowered and the construction cost is lower than that of the conventional type.

However, there are some points in which it is inferior to the bell-type blast furnace. That is, the first point is that it is difficult to charge the raw material concentrically around the furnace η111 center, and the second point is that the particle size distribution in the radial direction of the raw material charged into the furnace is One example is that it is difficult to control.

The first point above is that in the pelletless blast furnace, the
As illustrated in Publication No. 4082, a plurality of storage devices (hereinafter referred to as furnace top hoppers) installed at the furnace top are arranged side by side on the left and right with the furnace axis centered, and these furnace top hoppers The raw materials are cut out from each other and dropped onto the rotating chute through a flow port (hereinafter referred to as the vertical sheet) provided at the lower furnace axis and distributed into the furnace. Because the raw material is installed at an offset position, a horizontal component force is generated in the overculm where the raw material falls, and due to this component force, the raw material after being distributed into the furnace does not fall in a concentric circle but has a distorted shape. becomes. Even if it is attempted to eliminate this distortion by controlling the tilting angle of the swivel seat, it is extremely difficult to completely eliminate this distortion.

Furthermore, the second point above is problematic in that the pelletless blast furnace does not have the excellent temporary properties of the bell blast furnace.

As mentioned above, the BP Lebel blast furnace has the advantage that the raw material is distributed throughout the furnace, so the falling point of the raw material charged into the furnace becomes a circular ring centered on the furnace axis. The advantage of this falling position is not inferior to that of the bell's ability to classify raw material grains. This classification effect is caused by the phenomenon that when the raw material slides down the bell and falls into the furnace, larger particles fall further away than smaller raw material particles. When charging raw materials in a bell-type blast furnace, the falling point of the raw materials is limited, and even considering that the dropping position can be adjusted using a movable armor, the profile that can be formed inside the furnace is V or M. Becomes a mold. Therefore, the raw materials that slide down the bell and fall into the furnace tend to fall onto or near the top of the charged raw materials, and here they also slide in the direction of the furnace axis along the profile of the raw materials inside the furnace. Then, the coarse particles are subjected to a classification action that causes them to roll toward the furnace axis, forming a new profile according to the angle of repose specific to the raw material. In other words, when charging raw materials into a bell-type blast furnace, natural classification occurs so that the profile of the W and sum charged into the furnace is V or M type, and the grain size of the raw materials in the radial direction is coarser on the furnace axis side. It has the advantage that a favorable profile and radial particle size distribution of the raw material is naturally obtained.

However, since the pelletless blast furnace does not have a bell, it is convenient for blast furnace operation due to the formation of the profile obtained when charging raw materials in a bell type blast furnace and the natural classification of raw materials between the furnace axis and the furnace wall dimension. However, it is possible to easily form a profile in a pellet-less blast furnace, and it is also possible to form a complex profile that cannot be obtained in a bell-type blast furnace. It is extremely difficult to control the particle size distribution in the radial direction down to the wall in a desirable manner, and this has been a technical problem that must be solved in the pelletless blast furnace.

In this way, in the method of charging raw materials in a pelletless blast furnace, it is important to ensure that the raw materials charged into the furnace do not form a nearly perfect circle, and that the raw materials are Therefore, those skilled in the art continue to make efforts to solve the above technical problems of pelletless blast furnaces and to perform good blast furnace operations. That's where I am.

To exemplify the improvement measures for the above problem that have been proposed so far, Japanese Utility Model Publication No. 57-18425 discloses that by making the angle between the inner bottom surface and the inner surface of the rotating sheet an acute angle, the raw material that has fallen onto the rotating chute is A technique has been disclosed in which the position and velocity of the raw material at the time of discharge are constant even if the falling points of the raw material are different, and the falling position of the raw material in the furnace is made to approximate a perfect circle.

However, in conventional pellet-less blast furnaces, two furnace top hoppers installed at the top of the furnace were installed side by side on both sides of the blast furnace axis, so the horizontal component force when the raw material falls into the furnace caused the material to be charged into the furnace. There is an essential drawback in that the raw material produced does not form a ring shape, so even if the shape of the chute is improved and the chute is charged, it will not solve the essential drawback of target distribution.

As a technique to solve this essential drawback, JP-A-56-3
As disclosed in Japanese Patent Application Laid-Open No. 3411, Japanese Unexamined Patent Publication No. 56-87613, and Japanese Utility Model Application No. 57-59850,
Techniques have been proposed in which furnace top hoppers are installed vertically or concentrically around the axis of the blast furnace. According to these techniques, the raw material cut out from the furnace top hollow falls without generating any horizontal component force, so the furnace top hollow/e
The above-mentioned essential drawbacks of the pellet-less type blast furnace installed side by side can be solved, and furthermore, by using the rotating chute disclosed in the above-mentioned Japanese Utility Model Publication No. 57-18425, one of the technical problems to be solved with the pellet-less type blast furnace can be solved. As shown in the first point above,
We have reached the point where we have been able to solve the problem that the falling locus of the raw material charged into the furnace in the circumferential direction does not form a circular ring.

However, an effective technique for controlling the radial particle size distribution of the raw material charged into the furnace, which is the second technical problem to be solved for the pelletless blast furnace, has not yet appeared. However, there have been many proposed technologies for charging raw materials into blast furnaces that focus on this particle size distribution.

For example, Japanese Patent Publication No. 55-16203 discloses a technique for charging a solid reducing agent (coke) into a blast furnace according to particle size;
Publication No. 5-62106 discloses that iron-containing raw materials such as sintered ore and raw materials consisting of coke are divided into a plurality of types each having a predetermined particle size, and the method is divided into a plurality of types, each having a predetermined particle size. A technology has been disclosed in which the type of raw material to be charged, the amount to be charged, and the location to be charged are selected and charged separately. A technique has also been disclosed in which the iron-containing raw material and coke are charged so that the deposited layer thicknesses thereof reaching the wall portion are constant.

These particle size-based charging technologies for charging raw materials in blast furnaces are effective in improving blast furnace productivity, reducing fuel consumption, and stabilizing blast furnace operations, and are attracting attention as a technology that should be widely used and widely used in blast furnace operations in the future. has been done.

However, in order to carry out the above-mentioned charging according to particle size in a blast furnace, it is necessary to have classification equipment to pre-sort iron-containing raw materials such as coke and sintered ore according to particle size, and an ore storage tank to store the classified raw materials. However, there is a problem in that the number of ore storage tanks must be set up for each type of raw material and particle size, which increases equipment costs and complicates operations such as management of raw materials for each classification and charging schedule. Moreover, even if the raw materials are classified by particle size, they each have their own particle size distribution, and when this is charged into the furnace in a pelletless blast furnace, the particle size distribution of the raw material changes each time it is charged. It is difficult to grasp this particle size segregation, so even if charging is carried out by particle size, the effect inevitably decreases by the amount caused by the particle size segregation.

Therefore, if it is possible to control the particle size distribution in the radial direction and charge raw materials according to particle size in the method of charging raw materials in a pelletless blast furnace, the operation of the pelletless blast furnace will be dramatically improved. It was eagerly awaited.

The present invention was made in view of the above situation, and when charging raw materials into the furnace using a pelletless type furnace top charging device in which furnace top hoppers are installed in two vertical stages, this type of furnace top charging device is used. It is an object of the present invention to provide a method for advantageously carrying out charging of raw materials according to particle size by utilizing the natural classification effect of raw materials, which is a phenomenon unique to charging equipment. That is, the present invention provides: (1) A method for charging raw material into a blast furnace using a blast furnace top charging device in which a top hopper is installed coaxially with the furnace axis in two stages and a rotating chute is provided in the furnace; The average particle size of the raw material in the hopper from the start of discharge to the end of discharge is known in advance over time, and the tilting angle of the rotating seat is controlled based on the change in the average particle size determined in advance. (2) The tilting angle of the rotating sheet is controlled so that the raw material having a small average particle size is charged to the side of the furnace wall. The method for charging raw materials into a blast furnace according to item 0, (3)
(1) above, wherein the change over time in the average particle size of the raw material discharged from the furnace top hopper is understood by forming a pattern;
(4) The pattern is determined for each type of raw material and the opening degree of a flow rate regulating valve provided at the bottom of the top popper of the blast furnace. The gist is the raw material charging method.

The present invention will be described in detail below based on the drawings.

FIG. 1 is a longitudinal sectional view illustrating a pelletless blast furnace according to the present invention.

As shown in FIG. 1, the pelletless blast furnace according to the present invention is
The blast furnace 1 has a rotating chute 1-3e at the top of the furnace that rotates around the furnace axis 2 and distributes the raw material.
The angle of inclination can be arbitrarily changed irrespective of the rotation of the seat. At the top of the furnace, a lower furnace top hopper 4 and an upper furnace top hopper 5 are installed coaxially with the furnace axis 2, and six seal valves are installed at the bottom of the lower furnace top hopper 4. Top and bottom hopper
The opening degree can be set as desired with the furnace axis center 2 as the center, and the seal valve 3A is located directly above the seal valve 3A. A gate valve 7A is provided which has the function of adjusting the flow rate of the falling raw material.

In addition, a seal valve 6 is provided between the lower furnace top hollow/middle-4 and the upper furnace top hopper 5, that is, at the bottom of the upper furnace top hollow/P-5.
B and a dart valve 7B are provided directly above it, the seal valve 6B of and has the same function as the six seal valves, and the dart valve 7B has the same function as the gate valve 7A. However, it is also possible to simply provide an opening/closing function.

At the top of the upper furnace top box 5, there is a belt conveyor 8 for dropping the raw material to the vicinity of the furnace axis 2. Eight people at the upper end of this belt conveyor 8 and an upper furnace top box 5 are installed. An upper revolving seat 9 is provided between the belt conveyor 8 and the ore storage tank (not shown) provided on the ground.
After the raw material is transported to the furnace top, the raw material that falls through the upper end 8A is charged into the upper furnace top hopper 5 while rotating through this chute 9. In the figure, 10 is a drive device N for driving the upper swing chute 9, IIA and IIB are gears,
12 indicates a support roller.

FIGS. 2(a) and 2(b) are bottom views illustrating the dart valve 7A according to the present invention, and the type shown in FIG. The blade plates 25, 26, 27, and 28, which are each rotatably installed, are rotated at the same angle to form an opening A in the center, and the type shown in FIG. Two metal plates 31 and 32 with a right-angled bevel in the center are installed so that they can rotate or slide against each other, and these metal plates 31 and 32 can be rotated or slid against each other. It is of the type that slides into contact and forms an opening B in the center.

The openings A and B have in common that the cross-sectional area of the opening can be set to a preset value, and that the cross-sectional area changes around the axis of the furnace, and these points are unique to the present invention. It is one of the important structures in the perleless blast furnace.

Note that the lower furnace top hopper 4 has a function of equalizing the exhaust pressure, but the equalizing pressure itself is a function provided in any type of blast furnace and is a well-known function, so the explanation is omitted. do.

Next, the classification action of raw materials in the Pelleless high f''K system, which is the basis of the method of the present invention, will be explained.

In the pelletless blast furnace illustrated in Fig. 1, after the raw material is transported to the top of the furnace by the belt conveyor 8, the upper rotating
) 9 is rotated and charged into the upper furnace top hollow 9-5, the raw material is charged evenly in the circumferential direction around the furnace axis 2 into the upper furnace top hollow 9-5. This means that even if the shellfish or the raw material has a predetermined particle size distribution, a portion of it will be exposed to the top of the oven! -5, particle size segregation in the circumferential direction around the furnace axis becomes extremely small.

The raw material charged into the top hopper arm 5 of the J1 section is transferred to the lower top hopper by opening the seal valve 6B and opening the gate valve 7B after reducing the pressure in the bottom top hopper 4 to atmospheric pressure. However, the raw material falls into the upper furnace top hopper 5 at the bottom of this furnace top hopper. Since the raw material charged into the lower furnace top hollow ♀-4 falls through an opening with a significantly smaller diameter compared to the diameter of the In addition, the inner wall of Hoy 1R-4 is subjected to a natural classification effect in which many large-diameter raw materials gather. That is, when the raw material in the two-part furnace top hopper 5 falls into the lower furnace top hopper 4, the first material that falls falls and accumulates at the center bottom of the lower furnace top hopper 4, and the raw material is This results in the formation of a υ convex profile due to the angle of repose of . Although the raw material falls continuously, the falling position always meets the top of the convexly deposited raw material, so when the raw material flows radially from the top, large diameter raw materials rise and roll far away. The raw material with a small diameter is subjected to a classification action such that it gathers near the inner wall of the conch/P-hole, and the raw material with a small diameter is largely deposited at the core of the furnace shaft.

In this way, the classification in the lower furnace top hopper 4 is similar to the natural classification that occurs in a bell-type blast furnace when raw materials are charged, but is exactly the opposite in terms of particle size distribution in the radial direction around the furnace axis. It will be affected.

The raw material in the five-part furnace top hopper 4, which was charged after being subjected to a classification action such as The dart valve 7A is opened to a predetermined opening degree, and the rotating seat 3-\ provided in the furnace is charged so as to be distributed into the dropping furnace. It will be charged into the furnace after being subjected to classification action.

That is, when charging raw materials into the furnace from the first furnace top hopper 4, the raw materials falling through the dart valve 7A are transferred to this hopper 4.
The raw material located at the bottom of the axis of the hopper 4 is discharged first, and the raw material located on the wall of the hopper 4 is discharged later, resulting in a classification effect, so that the particle size of the raw material being charged into the furnace does not change over time. The particle size is extremely large, and the difference in particle size between the beginning and end of charging is significant.

Figure 3 is a diagram showing an example of the change over time, showing the elapsed time from the start of the raw material outflow when the raw material was charged into the furnace under the conditions shown in Table 1, and the amount of raw material discharged at that time. It shows the relationship with the average particle size.

Table 1 Average grain size was determined by yard sampling of imported sintered ore.

The present invention utilizes such a phenomenon to solve problems in charging raw materials in a bellless blast furnace.

In the present invention, the change over time in the average particle size of the raw material, as illustrated in FIG. 3, is a phenomenon unique to the pelletless blast furnace according to the present invention. This method is based on the fact that high reproducibility can be achieved by limiting conditions such as the opening degree of the gate valve.

Of course, this differs depending on the equipment, but since it remains unchanged once it is constructed, it can be made unique to the blast furnace, and when the equipment is changed due to design changes or repairs, etc. At that point, the basic f-number can be reset and corrected, and wear on the inner surface of the hopper or the dart valve can be dealt with by additional correction.

When carrying out the present invention, the relationship between the outflow time of the raw ore and the average particle diameter of the raw material illustrated in FIG. It is effective to keep it. In addition, by storing the patterns using a computer, the patterns required in actual operation can be retrieved instantaneously and used for control. Of course, the pattern may be expressed using a mathematical formula or the like.

Next, the raw material charging method of the present invention will be explained.

The present invention uses the bellless blast furnace according to the present invention illustrated in FIG. 1, and based on the relationship between the outflow time of the raw material and the average particle size of the raw material illustrated in FIG. The average particle diameter of the raw material is estimated and the rotation is made based on this estimated value.

- The raw material is charged into the furnace by controlling the tilting angle of the tray.

FIG. 4 is a block diagram illustrating the method of the present invention.

As shown in FIG. 4, the pattern setter 44 sends a control device 41 that controls the rotation speed and tilting angle of the rotation chute 3 to the pattern illustrated in FIG. Type of raw material.

A plurality of types of conditions are entered for operational purposes such as the average particle size and the opening degree of the dart valve 7A and the opening degree of the dart valve 7A and r -) Enter the elapsed time since the opening of the valve 7A, and input from the charging condition setting device 45 the 70 rofile of the raw material to be fed into the furnace, the particle size distribution in the radial direction from the furnace axis to the furnace wall, and the raw ore layer. After inputting the conditions such as thickness distribution, is the lower furnace top exposed? The average particle size of the raw material falling every moment from -4 is estimated based on the above pattern, and based on this estimated value, the tilting angle of the rotating sheet is controlled and the raw material is charged.

That is, the type of raw material contained in the lower furnace top hopper 4, for example, whether it is ore or coke, and the average particle size of the raw material are known before charging into the furnace. is input from the raw material condition setting device 42 to the control device ff, 41 to determine the properties of the raw material in the lower furnace top popper 4, that is, the type of raw material.

The pattern illustrated in FIG. 3 for each degree of opening of the dart valve for raw materials having the same amount and average particle size is also input into the control device 41 in advance, so that when the dart valve 7A is opened to a predetermined opening, the particles will fall. The change over time in the average particle size of the raw material to be dropped can be determined by knowing the elapsed time since it started falling from the lower furnace top hopper 4. Predictable. Therefore, the tilting angle of the rotating chute 3 is controlled based on the change in the average particle diameter over time, and the raw material is charged so as to satisfy preset operating conditions.

For example, if the profile of the raw material in the furnace is M-shaped and the blast furnace is operated with fine-grained raw material charged near the furnace wall and coarse-grained raw material charged into the core of the furnace, In the case of the test plate 1 pattern in Figure 3, the tilting angle of the rotating sheet is increased for 25 seconds after starting to discharge the material from the lower furnace top hole, and one grain original is charged near the furnace wall. , for 25 to 60 seconds, the average particle size becomes small over time, so if the tilting angle of the rotating sheet is gradually reduced and the material is charged in a spiral manner, the rough grain size in the radial direction of the raw material charged into the furnace is The particle size distribution shows that the grains are fine at the furnace wall and coarse at the core of the furnace, and the average particle size of the raw material in the radial direction from the core of the furnace can also be determined.

Regarding the profile of the raw material in the furnace, the charging position of the raw material must be determined in consideration of the relationship with the profile of the raw materials that have already been charged, but according to the present invention, the charging position of the raw material and Since it is possible to grasp the average particle size at the location of the person in question, the particle size distribution in the radial direction of the furnace can be controlled simply by forming a profile in the sweat in a predetermined shape. The above is very informative.

The method of the present invention not only makes it possible to charge raw materials according to particle size without dividing them into sections in advance, but also Even when separate charging is performed, it is possible to perform charging according to the present invention by utilizing the raw material particle size distribution within 4 minutes, and it is possible to perform charging according to the finer particle size. It is.

As described above, the present invention utilizes the raw material classification effect unique to the pelletless blast furnace, which has multiple stages of furnace top holes coaxial with the furnace axis, to charge raw materials according to particle size. Because of this, it has an extremely significant effect on reducing blast furnace construction costs and blast furnace operation.

[Brief explanation of the drawing]

FIG. 1d is a longitudinal cross-sectional view illustrating a pelletless blast furnace according to the present invention, FIGS. The figure is a diagram illustrating the relationship between raw material outflow time and average particle size, and FIG. 4 is a block diagram illustrating the method of the present invention. 1: Blast furnace, 2: Furnace axis, 3... Rotating seat, 4: Lower furnace top hopper, 5: Upper furnace top hopper, 6A, 611
: Seal valve, 7A, 7B: Dart valve, 21-24: Shaft,
25-28: Feather plate, 31, 32: Metal plate, A, El
: opening, 41: control device, 42: raw material condition setting device, 4
3: Key-1 valve controller, 44: /'P turn setting device, 45: Charging condition setting device.

Claims (3)

[Claims] (1) In a method for charging raw materials into a blast furnace using a blast furnace top charging device in which the top popper is installed coaxially with the furnace axis in two stages and a rotating chute is provided in the furnace, the raw material in the lower furnace top hole 9 is The average particle size of the raw material over time from the start of discharge to the end of discharge is known in advance, and the tilting angle of the rotating seat is controlled based on the change in the average particle size determined in advance over time to feed the raw material into the furnace. A method for charging raw materials into a blast furnace characterized by charging. (2) The method for charging materials into a blast furnace according to claim 1, wherein the tilting angle of the rotating chute is controlled so that the material having a small average particle size is charged to the side of the furnace wall. (3) The method for charging raw materials into a blast furnace according to claim 1, wherein the change over time in the average particle diameter of the raw material discharged from the top of the furnace is patterned and grasped in advance. (i) The method for charging materials into a blast furnace according to claim 3, wherein the pattern is determined by Jg, another type, and an opening degree of 4σ of a meteor adjustment valve provided at the top and bottom of the furnace.