JP2011017068A - Chute for charging raw material into relay hopper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the grain size segregation of a raw material to be discharged from a relay hopper.SOLUTION: A chute 11 for charging the raw material is provided on the upper part of the relay hopper 4 which is arranged upstream of a belt conveyor 5 for charging the raw material into a top furnace bunker, when the raw material is transported to a bell-less blast furnace. The chute 11 includes: a funnel-shaped slope 11a; a straight pipe 11b which is arranged in the lower part of the slope; further a reverse funnel-shaped part 11c widening toward the bottom, which is continuously provided in the lower part of the chute; and a rebounding plate 11d which is arranged in an inner wall of the reverse funnel-shaped part 11c for cancelling a speed component in a horizontal direction of the raw material. Accordingly, a deposition angle of the raw material becomes small in the relay hopper and the grain size segregation becomes small when the raw material is discharged. Thereby, the grain size segregation of the discharged raw material becomes large in the top furnace bunker, which is an advantageous condition for the raw material to be charged in securing the permeability of the blast furnace.

Description

  The present invention relates to a chute for raw material charging to a relay hopper that discharges the raw material to a belt conveyor that conveys and charges the raw material to a furnace top bunker arranged at the top of the blast furnace top, particularly from the relay hopper The purpose is to suppress particle size segregation of the discharged material.

  In the bell-less blast furnace charging device, ore as an iron source and coke as a reducing material (hereinafter, ore and coke are collectively referred to as “raw material”) are temporarily stored and discharged in a furnace bunker, It is charged into the blast furnace from the top of the blast furnace through a turning chute.

  At that time, the particle size segregation state of the raw material discharged from the top bunker affects the in-furnace air permeability and the in-furnace radial gas flow distribution through the charge distribution in the blast furnace.

  By the way, when charging a raw material into a furnace top bunker using a belt conveyor, a relay hopper may be installed upstream of the belt conveyor. In this case, as shown in FIG. 6, the raw material 2 conveyed from each raw material tank by the belt conveyor 1 is temporarily stored in the relay hopper 4 via the chute 3 and then discharged to the belt conveyor 5 to be sent to the top of the furnace. Transported to a bunker.

  Hereinafter, the belt conveyor 1 for charging the raw material into the relay hopper 4 is referred to as “the raw material charging belt conveyor 1 for the relay hopper”, and the belt conveyor 5 for charging the raw material into the furnace bunker is referred to as “the raw material for the furnace bunker”. This is referred to as the “load belt conveyor 5”.

  In a blast furnace, in order to ensure air permeability in the furnace, an operation state in which the gas flow rate in the center of the furnace is strong is generally directed. However, since the gas flow distribution in the furnace is determined by the weight ratio of the ore and coke charged, the layer thickness, and the particle size distribution in the furnace radial direction, in order to obtain the desired gas flow distribution in the furnace, It is necessary to adjust the conditions of these charges.

  The bell-less blast furnace charging device turns while turning the turning chute and charges the raw material into the furnace. Here, tilting means changing the angle formed between the central axis of the turning chute and the central axis in the blast furnace vertical direction.

  Usually, the turning chute is operated so as to gradually tilt toward the furnace center side in the direction of the furnace wall side when charging is started. Therefore, when controlling the radial distribution of the raw material in the furnace in the operation state where the gas flow rate in the furnace center is strong, fine particles are added at the beginning of charging (furnace wall side), and at the end of charging (furnace center). It is desirable to control the particle size segregation of the raw material discharged from the furnace top bunker so that the coarse particles are discharged over the part.

  For example, Patent Document 1 discloses an apparatus that controls a particle size segregation of a raw material deposited in a furnace top bunker by providing a tiltable movable plate that changes the falling direction of the raw material in the furnace top bunker.

  However, in the case of the material transfer system of the bell-less blast furnace in which the relay hopper is arranged upstream of the furnace top bunker, the segregation state of the furnace top bunker is affected by the particle size segregation of the material discharged from the relay hopper located upstream thereof. Therefore, in order to obtain a desired gas flow distribution, it is necessary to control particle size segregation in the relay hopper simultaneously with the furnace bunker.

  Therefore, in Patent Document 2, a material that falls from the belt conveyor to the relay hopper is divided into two in the belt width direction, and a chute is attached to adjust the material flow so that the dropping position is symmetric with respect to the central axis of the relay hopper. Have been disclosed.

  However, when the apparatus disclosed in Patent Document 2 is used, the raw material divided into two forms piles in the vicinity of the wall of the relay hopper. Therefore, there are fine grains near the top of each pile, coarse grains on the wall that becomes the bottom of the pile, and coarse grains in the center of the relay hopper that forms the bottom of both piles. It becomes complicated and its control becomes difficult.

  An apparatus for preventing segregation in a relay hopper intended to solve the problem in Patent Document 2 is disclosed in Patent Document 3. This segregation prevention device is provided with a chute in which a mixing plate is provided in a funnel shape at a belt conveyor end of a material conveyance system to a relay hopper to form a grooved discharge port, and a mixing plate facing the conveyance end of the chute is provided. By providing a repulsion plate above, particle size segregation in the relay hopper is suppressed.

  In Patent Document 3, there is no specific description about the width dimension of the belt conveyor and the relay hopper. However, when the width of the belt conveyor and the relay hopper is the same as shown in FIG. Consecutive piles are formed, and it is thought that segregation of grain size is suppressed.

  However, in general, the width of the relay hopper is sufficiently large with respect to the belt conveyor (for example, about 2.5 to 5 times), so that a continuous pile of piles is formed over the entire width of the relay hopper. And a sufficient particle size segregation suppressing effect cannot be obtained.

  On the other hand, when charging the raw material from the belt conveyor to the relay hopper, a funnel-shaped chute may be provided on the upper portion of the relay hopper in order to form the top of the accumulated raw material peak near the center of the relay hopper.

  In this case, since the raw material supplied from the raw material charging belt conveyor to the relay hopper flows along the slope 3a of the funnel-shaped chute 3 as shown in FIG. 7, it has velocity components in the vertical direction and the horizontal direction. It will be.

  When the lower part of the funnel-shaped chute 3 is a straight pipe 3b, as shown in FIG. 7, when the raw material that has left the slope 3a of the chute 3 collides with the inner wall of the straight pipe 3b, the velocity component in the horizontal direction is reduced. It is canceled and falls vertically, and the peak of the raw material peak is near the center of the relay hopper.

  Thereby, it is possible to avoid that the peak of the peak of the raw material is formed outside the center of the relay hopper and that the peak fluctuates. However, since the deposition vertex of the raw material is a part, as in the technique disclosed in Patent Document 3, a sufficient particle size segregation suppressing effect cannot be obtained.

JP 2000-178624 A Japanese Patent Publication No. 1-030886 JP-A-6-009063

  The problem to be solved by the present invention is that the conventional technology cannot sufficiently suppress the particle size segregation of the raw material discharged from the relay hopper.

The material charging chute to the relay hopper of the present invention is
In order to sufficiently suppress the particle size segregation of the raw material discharged from the relay hopper,
When conveying the raw material to the bell-less blast furnace, a raw material charging chute provided on the upper part of the relay hopper installed upstream of the raw material charging belt conveyor to the furnace top bunker,
At the bottom of the chute provided with a straight pipe at the bottom of the funnel-like slope, a reversing reverse funnel-like portion is continuously provided, and the repulsion that cancels the horizontal velocity component of the raw material on the inner wall of the reverse funnel-like portion The main feature is the installation of a board.

  The material charging chute to the relay hopper of the present invention is provided with a continuous reverse funnel-shaped portion continuously at the lower portion of the straight pipe and repelling the horizontal velocity component of the material on the inner wall of the reverse funnel-shaped portion. Since the plates are installed, the dropping positions of the raw materials charged into the relay hopper are dispersed.

  In the present invention, since the drop positions of the raw material charged into the relay hopper are dispersed, the raw material deposition angle in the relay hopper is reduced, and the particle size segregation during the discharge of the raw material is reduced. Thereby, in the furnace top bunker, the particle size segregation of the discharged raw material becomes large, which is an advantageous raw material charging condition for ensuring the air permeability of the blast furnace.

It is a figure which shows the principal part of the chute | shoot for raw material charging to the relay hopper of this invention, (a) is a longitudinal cross-sectional view, (b) is a top view. It is the figure which showed the raw material deposition profile in a relay hopper at the time of using the chute | shoot of this invention, and the conventional chute | shoot. It is the figure which showed the raw material particle size sampled from the sedimentary mountain shown in FIG. It is the figure which predicted the particle size segregation state of the raw material discharged | emitted from a relay hopper by model calculation. It is the figure which predicted the particle size segregation state of the raw material discharged | emitted from a furnace top bunker by model calculation. It is a figure which shows schematic structure of a relay hopper. It is a figure which shows the principal part of the conventional vertical chute, (a) is a longitudinal cross-sectional view, (b) is a top view.

  In the present invention, for the purpose of sufficiently suppressing the segregation of the particle size of the raw material discharged from the relay hopper, a reverse funnel-shaped portion continuously spreading at the bottom of the straight pipe is continuously provided, and the raw material is provided on the inner wall of the reverse funnel-shaped portion. This was realized by installing a repulsion plate that counteracts the horizontal velocity component of.

The best mode for carrying out the present invention will be described below with reference to FIG.
11 is a chute for raw material charging to the relay hopper of the present invention installed upstream of the raw material charging belt conveyor to the furnace top bunker, and below the straight pipe 11b provided at the lower portion of the funnel-shaped slope 11a, Further, the following components are arranged in succession.

  11c is a divergent reverse funnel-shaped portion 11c continuously provided at the lower portion of the straight pipe 11b. A repelling plate 11d that cancels the horizontal velocity component of the raw material is formed on the inner wall of the reverse funnel-shaped portion 11c, for example, A plurality are installed at the same position in the direction.

  In the chute 11 of the present invention having such a configuration, the angle formed by the inclined surface 11a is θ, the inner diameter of the straight pipe 11b is Da, the length is La, and the inner diameter of the lower end of the reverse funnel portion 11c is Db (FIG. 1). It is desirable that the relationship represented by the following formula 1 is established.

  In the present invention, the length Lb of the reverse funnel-shaped portion 11 c and the inner diameter Db of the tip of the reverse funnel-shaped portion 11 c may be adjusted according to the size of the relay hopper 4. Moreover, it is necessary to adjust the internal diameter Dc (refer FIG. 1) of the circle | round | yen which the repulsion board 11d installed in the inner wall of the reverse funnel-shaped part 11c forms according to a raw material particle size. If this inner diameter Dc is made too small, the raw material temporarily stays in the straight pipe 11b portion located above the repulsion plate 11d and drops vertically after the horizontal velocity component is completely cancelled. This is because the effects of the invention cannot be obtained.

  Since the raw material supplied from the raw material charging belt conveyor to the relay hopper flows along the slope of the chute, it has velocity components in the vertical direction and the horizontal direction. In the case of the conventional chute 3 having the shape shown in FIG. 7, the raw material that has left the inclined surface 3a collides with the inner wall of the straight pipe 3b, so that the velocity component in the horizontal direction is canceled and falls in the vertical direction.

  On the other hand, in the present invention, as shown in FIG. 1, since the reverse funnel-shaped portion 11c is continuously provided in the lower portion of the straight pipe 11b, the raw material that has left the inclined surface 11a collides with the inner wall of the straight pipe 11b. Without reaching the reverse funnel 11c. Accordingly, the horizontal speed component is inserted into the relay hopper 4 without being canceled. Moreover, a part of the raw material is mixed by the dispersion caused by the collision with the repulsion plate 11d provided in the reverse funnel-shaped portion 11c and the collision between the raw materials, and the velocity component in the horizontal direction is canceled and falls in the vertical direction.

  As described above, according to the present invention, the conventional chute 3 shown in FIG. 7 has one effect due to the effect of the reverse funnel-shaped portion 11c that is continuously provided at the lower portion of the straight pipe 11b and the repulsion plate 11d provided on the inner wall. It is possible to disperse the material dropping positions on the relay hopper concentrated in the station.

  As a result, the piles formed by the raw material charged into the relay hopper 4 via the chute 11 of the present invention shown in FIG. 1 become gentle, and the segregation effect caused by the rolling of the raw material on the surface of the pile is reduced. . Therefore, the particle size segregation of the raw material discharged from the relay hopper 4 to the charging belt conveyor 5 to the furnace top bunker is reduced.

Next, the result of verifying the effect of the present invention by a model experiment will be described.
FIG. 2 shows a deposition profile after the raw material is charged into the relay hopper 4 using the chute 11 of the present invention shown in FIG. 1 and the conventional chute 3 shown in FIG.

  When standardized by the height and horizontal distance of the raw material pile formed after charging the raw material with a conventional chute, when using the chute of the present invention, the formed raw material pile is lower due to the dispersion effect of the raw material falling point. The deposition angle gradually decreased.

  The raw material particle size sampled from the sedimentary mountain shown in FIG. 2 is shown in FIG. 3. When the chute of the present invention is used, the particle size segregation on the sedimentary mountain slope is smaller than when the conventional chute is used. It turns out that it is suppressed.

  Next, based on the result of the model experiment, the effect of the present invention in the actual blast furnace was predicted by model calculation.

  Fig. 4 shows the particle size segregation state in the relay hopper in the model experiment and the particle size segregation state of the raw material discharged from the relay hopper when the charging order of each brand into the relay hopper of the actual blast furnace is used as the input condition. . Further, FIG. 5 shows the particle size segregation state of the raw material discharged from the furnace top bunker when the particle size segregation state of the raw material discharged from the relay hopper is used as an input condition.

  From FIG. 4, it can be seen that the use of the chute of the present invention can suppress the particle size segregation of the raw material discharged from the relay hopper compared to the case of using the conventional chute.

  Therefore, it can be seen that if the chute of the present invention is used, the particle size segregation of the raw material discharged from the furnace top bunker becomes larger than that in the case of using the conventional chute as shown in FIG.

  It goes without saying that the present invention is not limited to the above-described examples, and the embodiments may be appropriately changed within the scope of the technical idea described in each claim.

  For example, the repulsion plates 11d provided on the inner wall of the reverse funnel portion 11c do not necessarily have to be provided at equal intervals in the circumferential direction.

  The present invention described above is not limited to the chute provided on the upper part of the relay hopper, and any raw material tank can be used as long as it is installed on the upper part of the raw material tank to suppress particle size segregation of the raw material discharged after temporarily storing the raw material. A chute may be provided.

DESCRIPTION OF SYMBOLS 1 Raw material charging belt conveyor to relay hopper 2 Raw material 4 Relay hopper 5 Raw material charging belt conveyor to furnace top bunker 11 Chute 11a Slope 11b Straight pipe 11c Upper part of reverse funnel 11d Rebound plate

Claims (2)

When conveying the raw material to the bell-less blast furnace, a raw material charging chute provided on the upper part of the relay hopper installed upstream of the raw material charging belt conveyor to the furnace bunker,
At the bottom of the chute where a straight pipe is provided at the bottom of the funnel-shaped slope, a reverse funnel-shaped part that further spreads out is continuously provided, and the repulsion that cancels the horizontal velocity component of the raw material on the inner wall of the reverse funnel-shaped part A chute for charging raw materials into a relay hopper, characterized in that a plate is installed. Of the shoot,
The angle formed by the funnel-shaped slope is θ,
The inner diameter of the straight pipe part is Da, the length is La,
2. The chute for charging raw material into the relay hopper according to claim 1, wherein when the inner diameter of the lower end of the reverse funnel is Db, the relationship shown in the following two equations is established.
Da <Db
La ≦ Da × tanθ

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