JP4591520B2 - Raw material charging method for blast furnace using furnace top bunker and bellless type charging equipment - Google Patents

Description

The present invention relates to a raw material charging method for a blast furnace using a furnace top bunker and a bellless type charging device, and more specifically, provided at the top of a blast furnace equipped with a so-called bellless type raw material charging device, In this technique, the particle size of the raw material charged into the blast furnace is adjusted using a furnace top bunker that stores the raw material in a swivel chute.

  In recent years, during blast furnace operation, the particle size distribution in the furnace of the charge is appropriately adjusted, the flow distribution in the furnace radial direction of the gas rising in the furnace is adjusted, the air permeability in the furnace, the reduction of raw materials, and the furnace body The heat load or the like is set in a desired state. Specifically, it is desirable to operate such that a large amount of gas flows through the center of the furnace (this is referred to as central flow orientation or central flow operation).

  Such gas flow distribution (hereinafter simply referred to as gas flow distribution) is mainly determined by the thickness ratio of the ore layer and coke layer formed in the furnace and the particle size in the furnace radial direction adjusted at the time of charging. Determined by distribution. In particular, when using a bellless type charging device equipped with a turning chute and having a bunker arranged in parallel at the top of the furnace, when the raw material is charged into the bunker, it is classified on the slope of the deposited raw material, and uneven distribution due to the particle size Arise. That is, as shown in FIG. 5, the raw material 4 that has fallen to the central portion in the bunker 2 moves the coarse particles 7 to the wall surface side away from the dropping position, so the fine particles 5 are in the central portion that is the dropping position. Coarse grains 7 are segregated and deposited around the bunker 2. As shown in FIG. 6, when the raw material 4 in such a deposited state is discharged from the bunker 2 (hereinafter referred to as the furnace top bunker 2) to the swivel chute 3 disposed below when the raw material 4 is charged into the blast furnace 8. The raw material of fine particles 5 in the first half and coarse particles 7 in the second half will come out. On the other hand, in the current blast furnace operation, the tip of the swivel chute 3 is swung while moving (tilting) from the peripheral side of the blast furnace 8 to the center, and the raw material 4 is charged as shown in FIG. It is common to form the surface 16 in a mortar shape (this is called forward tilting). Therefore, the material discharge behavior from the furnace top bunker 2 overlaps, and the raw material 4 of the fine particles 5, the coarse particles in the central portion 7, and the medium particles 6 in the middle are accumulated on the blast furnace wall side. A gas flow distribution with a developed central flow is easy to obtain.

  However, when depositing the raw material 4 in the furnace, it is more likely to roll the raw material from the upper side of the mortar-shaped slope from the furnace wall side when the raw material 4 is deposited from the center side, that is, from the lower side of the mortar-shaped slope. There is no phenomenon such as collapse of the deposition material, and a desired deposition shape is obtained. Therefore, it is considered preferable to turn the tip of the turning chute 3 while moving and tilting the tip of the turning chute 3 from the center of the furnace in the peripheral direction to charge the raw material 4 (reverse tilting).

  However, when the raw material 4 is charged into the furnace by turning while moving the tip of the swivel chute 3 from the center to the peripheral direction with the bellless type charging device described above, many fine particles 5 are accumulated in the center of the blast furnace 8. It is difficult to obtain a gas flow distribution in which the central flow is developed. That is, in this case, from the viewpoint of securing the central flow, it is desirable that the raw material 4 of the coarse particles 7 is discharged at the initial stage of discharge from the furnace top bunker 2.

As a method for adjusting the particle size of the raw material 4 discharged from the parallel-type furnace top bunker 2 over time, a hollow cylinder (not shown) that can be moved up and down is installed in the furnace top bunker 2 so as to be movable up and down. A technique is disclosed in which the raw material 4 having different particle sizes is stored inside and outside the cylinder, and the particle size of the raw material charged into the furnace is adjusted by appropriate use of the hollow cylinder at the time of dispensing (for example, Patent Document 1). reference). However, this technique has a problem that the structure of the furnace top bunker 2 becomes complicated with the arrangement of the hollow cylinder, the driving of the hollow cylinder is complicated, and maintenance is difficult.
Japanese Patent Laid-Open No. 61-157604

In view of such circumstances, regardless of the tilting direction of the transfer of the turning chute, the time course of particle size of the material to be paid out, using an adjustable furnace top bunker and bell-less type charging device in conventionally simple means It aims to provide a raw material charging method for the blast furnace.

  In order to achieve the above-mentioned object, the inventor diligently studied to segregate the raw material charged in the furnace top bunker according to particle size with the simplest possible structure. Then, it was confirmed that a movable plate tilted by a so-called “damper” method could be used, and the present invention was completed.

That is, the present invention is a raw material charging method for a blast furnace using a bellless type charging device provided with a turning chute and arranged in parallel with a bunker at the top of the furnace,
When the raw material to be charged into the blast furnace is temporarily stored, and the raw material is charged into the furnace through the furnace top bunker discharged to the swivel chute provided below,
When a tiltable movable plate is provided in the furnace top bunker, the raw material charged into the furnace top bunker is collided with the movable plate, and the tip of the turning chute is tilted from the periphery in the blast furnace toward the center. The movable plate is operated so that the direction in which the raw material falls is in the direction of the discharge of the furnace top bunker, and the drop position of the raw material charged into the furnace top bunker is set directly at the outlet of the raw material. As the upper part, fine particles gather near the discharge port from the deposition characteristics of the raw material in the furnace top bunker, and coarse particles gather at a position away from it,
When tilting the tip of the swivel chute from the center in the blast furnace to the peripheral direction, the movable plate is operated so that the direction of the raw material falls opposite to the discharge of the furnace top bunker. The position where the raw material charged into the bunker falls is a side wall away from the outlet, so that coarse raw material gathers near the outlet and fine grains gather far from the outlet,
A furnace top bunker and the raw material charging process of blast furnace using a bell-less type charging device, characterized in that depositing a coarse grain to the center of the blast furnace.

  In addition, the said movable plate is suitable if it inclines the collision surface of a raw material by inclining to both sides with respect to horizontal, and changes the fall direction. Further, in the present invention, the discharge port of the furnace top bunker is provided at a position close to one side from the center when viewed from above the bunker, and the movable plate tilts the raw material in the direction of the discharge port or in the opposite direction. Any material that can select the direction in which the raw material falls can be used.

  According to the present invention, raw materials can be dispensed from the top bunker in the order of coarse particles, medium particles, fine particles, or vice versa. As a result, it became possible to deposit coarse particles in the center of the blast furnace regardless of the tilting direction of the swivel chute, and a stable gas flow distribution with a developed central flow was obtained.

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

  First, FIG. 1 shows an outline of a furnace top bunker according to the present invention in a longitudinal section. It is a container (tank) at the top of the blast furnace 8 for temporarily storing the raw material 4 charged into the furnace. This raw material 4 is mainly iron ore (sintered ore) and coke, and both are intermittently charged separately from each other via a turning chute 3 provided below the container. , They will form alternating layers in the furnace. Therefore, a plurality of furnace top bunker 2 are usually provided (in parallel in FIG. 1) in consideration of the alternate charging convenience. Opening valves are provided at the top and bottom of the furnace top bunker 2 for charging, storing or discharging the raw material 4 to and from the bunker 2, respectively. That is, when the raw material 4 is discharged from the bunker 2 to the swivel chute 3, a two-stage valve (not shown) is operated to prevent the in-furnace gas from leaking to the atmosphere. .

  The furnace top bunker 2 according to the present invention is provided with a movable plate 1 that can be tilted above and inside the container (tank). As a result, the raw material 4 charged from the upper opening of the container (tank) collides with the movable plate 1 inclined at an appropriate angle, falls in different directions, and accumulates as shown in FIG. It becomes like this. In FIG. 2, the movable plate 1 is operated and the dropping position of the raw material 4 charged into the furnace top bunker 2 is set directly above the discharge port of the raw material 4. In this case, in the furnace top bunker 2, the fine particles 5 gather near the discharge port due to the deposition characteristics of the raw material 4, and the coarse particles 7 gather at a position away from it. Further, FIG. 3 shows a raw material accumulation state in a case where the dropping position of the raw material 4 charged into the furnace top bunker 2 is a side wall away from the discharge port. In this case, the raw material 4 of the coarse particles 7 is near the payout, that is, the fine particles 5 gather far from the mouth. That is, according to the present invention, by changing the tilt angle of the movable plate 1 in various ways, the raw materials 4 can be deposited in layers from the discharge port in order of particle size.

  The material, dimensions, and tilting fulcrum position of the movable plate 1 are not particularly limited in the present invention. Also, the shape is not particularly limited, but it needs to be large enough that the raw material charged into the furnace top bunker collides with the movable plate. Further, if the surface of the movable plate that collides with the raw material is formed in a box shape having an upward opening, a so-called stone box is preferable because wear of the movable plate due to the collision of the raw material can be reduced. In addition, it is sufficient that the tilt can be moved to both sides with respect to the horizontal, and the tilt angle is not limited. This is because it is sufficient to satisfy the function of switching the dropping position of the raw material 4 to the position directly above the discharge port or to the wall side away from the port. An example of the mechanism for tilting the movable plate 1 is shown in FIG. 9, but all known techniques may be used.

  Next, the usage method of the furnace top bunker 2 concerning this invention is demonstrated.

  As described above, the raw material 4 segregated according to the particle size in the furnace top bunker 2 obtained by the tilting operation of the movable plate 1 is discharged to the turning chute 3 provided below the bunker 2, and the chute 3 is passed through the chute 3. It is to go into the furnace. That is, the tip of the turning chute 3 is gradually tilted from the periphery in the blast furnace 8 toward the center and is turned. The tilting and turning speeds may be changed as appropriate according to the charging conditions at that time.

  Specifically, the raw material particle size distribution in the bunker 2 is shown in FIG. 2 so that the dropping position of the raw material 4 to the furnace top bunker 2 is directly above the discharge port (also called the discharge port). Thereafter, the raw material 4 is dispensed to the turning chute 3. In this way, the raw material 4 is discharged from the furnace top bunker 2 in the order of fine particles, medium particles, and coarse particles, and the coarse particles 7 and the fine particles 5 gather around the center of the blast furnace 8, so-called central flow. A gas distribution that enables operation can be obtained.

  On the other hand, when reverse tilting is performed in which the tip of the swivel chute 3 is swung while gradually tilting from the center of the blast furnace 8 toward the periphery, the dropping position of the raw material 4 in the furnace top bunker 2 is separated from the discharge port. The movable plate 1 is tilted so as to form a side wall to obtain the raw material particle size distribution shown in FIG. Then, by paying out to the turning chute 3 in the same manner as described above, the coarse particles 7 are collected at the center of the blast furnace 8 and the fine particles 5 are collected at the peripheral portion. Also in this case, a stable central flow can be secured in the operation of the blast furnace 8. FIG. 4 is a diagram showing a change with time of the raw material particle size discharged from the furnace top bunker 2 in the two cases. This particle size distribution survey was conducted using a so-called “rest” in an actual furnace.

  The above description is for obtaining a gas flow distribution in which the central flow is developed, but the furnace top bunker 2 according to the present invention is also effective when the peripheral flow is desired to be developed by the operator. That is, it is because the gas flow can be increased around the inside of the blast furnace by reversing the relationship between the tilting direction of the movable plate 1 and the tilting direction of the turning chute.

First, in the blast furnace 8 (with an internal volume of 4500 m ³ ) equipped with the conventional furnace top bunker 2 and the bell-less charging device, the tilting direction of the swiveling chute 3 at the time of charging the raw material is from the normal mode toward the center. The test operation was changed to the mode from the center to the periphery.

  The result is evaluated by the furnace top temperature distribution in the radial direction before and after the change of the turning direction of the turning chute and is shown in FIG. From FIG. 7, it is clear that by changing the tilting direction of the turning chute 3, the absolute value of the temperature is reduced and the central flow is suppressed. Note that a profile meter installed at the top of the furnace (not shown; for example, a microwave distance meter may be used) confirms that the charge accumulation shape has not changed during this period. is doing.

Next, in another blast furnace 8 (internal volume 5100 m ³ ) equipped with the furnace top bunker 2 and the bell-less charging device according to the present invention, from the mode in which the tip tilt direction of the turning chute 3 is normally performed from the periphery to the center. The pilot operation was changed to the mode from the center to the periphery. In that case, when adopting a mode in which the tip of the swivel chute 3 is tilted from the periphery toward the center, the movable plate is arranged so that the material dropping position in the furnace top bunker 2 is on the wall side away from the discharge port. An angle of 1 was manipulated.

  FIG. 8 shows the furnace top temperature distribution in the radial direction before and after the change of the turning chute tilting direction. From FIG. 8, there was no change in the temperature distribution, and a central flow could be secured even in the operation of tilting the swivel chute 3 from the center toward the periphery. In this case as well, the accumulation shape of the charge was not changed as described above.

It is a longitudinal cross-sectional view which shows the outline | summary of the furnace top bunker which concerns on this invention. It is a figure which shows the usage type of the furnace top bunker which concerns on this invention. It is a figure which shows another usage pattern of the furnace top bunker which concerns on this invention. It is a figure which shows the time-dependent change of the particle size by discharge | payout of the raw material in a bunker shown in FIG.2 and FIG.3. It is a longitudinal cross-sectional view which shows the outline | summary of the conventional furnace top bunker. It is a figure which shows the time-dependent change of the particle size of the discharge | payout raw material at the time of using the conventional furnace top bunker. It is a figure which shows the gas temperature distribution of the radial direction in the blast furnace top at the time of using a conventional furnace top bunker. It is a figure which shows the gas temperature distribution of the radial direction in the blast furnace top at the time of using the furnace top bunker which concerns on this invention. It is a figure which shows an example of the tilting means of the movable plate which concerns on this invention, (a) is a side view, (b) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable plate 2 Furnace top bunker 3 Turning chute 4 Raw material 5 Fine grain 6 Medium grain 7 Coarse grain 8 Blast furnace 9 Bearing 10 Motor 11 Rotating shaft 12 Support beam 13 Upper seal valve 14 Flow control gate 15 Lower seal valve 16 Material accumulation in the furnace surface

Claims (1)

A raw material charging method for a blast furnace using a bell-less charging device provided with a swivel chute and arranged in parallel with a bunker at the top of the furnace,
When temporarily charging the raw material to be charged into the blast furnace and charging the raw material into the furnace through a furnace top bunker that is discharged to the swivel chute provided below the blast furnace,
When a tiltable movable plate is provided in the furnace bunker, the raw material charged into the furnace bunker is made to collide with the movable plate, and the tip of the turning chute is tilted from the periphery in the blast furnace toward the center. The movable plate is operated so that the direction of the raw material falls in the direction of the discharge of the furnace top bunker, and the position of the raw material charged into the furnace top bunker is set directly at the outlet of the raw material. As an upper part, in the furnace top bunker, fine particles gather near the discharge port due to the deposition characteristics of the raw material, and coarse particles gather at a position away from it,
When the tip of the swivel chute is tilted from the center in the blast furnace toward the peripheral direction, the movable plate is operated so that the raw material falls in the opposite direction to the discharge from the furnace bunker. The position where the raw material charged into the bunker falls is the side wall away from the outlet, so that coarse raw material gathers near the outlet and fine grains gather far from the outlet,
Material charging process of blast furnace using the furnace top bunker and bell-less type charging device, characterized in that depositing a coarse grain to the center of the blast furnace.

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