JP5034566B2 - Raw material charging device and raw material charging method for bell-less blast furnace - Google Patents

Description

  The present invention relates to a raw material charging apparatus and a raw material charging method for a bell-less blast furnace having a center-feed type bell-less furnace top charging apparatus in which a raw material hopper is arranged in two stages at the top and bottom of the furnace.

  As a raw material charging device for a blast furnace, a bell type is widely adopted, but instead of a bell type, a furnace top charging device of a type that does not have a bell with a turning chute in the furnace has been developed. It is used and is called a bell-less charging device.

  The bell-less charging equipment has a “parallel hopper type” in which the furnace hopper is installed in parallel and a raw material hopper in two stages, upper and lower, via ports etc. from the upper hopper to the lower hopper. It is known that there is a “center feed type” that supplies materials. An example of a center-feed type bell-less charging device is shown in FIG.

  In general, the center-feed type bell-less charging device is structurally simple compared to the parallel hopper type device, so the capital investment is low, and the cost for charging the charged material into the furnace is low. There is an advantage that the circumferential deviation is small and the distribution can be performed almost uniformly (see, for example, Patent Document 1).

  On the other hand, if a raw material charging device with two hoppers at the top and bottom like the center-feed type bellless device is used, the furnace height tends to be high, and the height of the device is used for reasons such as diverting existing equipment. Therefore, it is necessary to secure the internal volume by increasing the diameter of the upper and lower hoppers.

  However, by increasing the diameter of the upper and lower hoppers, the coarse and fine grains in each hopper when the raw material is received into the upper hopper or when the raw material is charged from the upper hopper to the lower hopper. The tendency to segregate is promoted. This is due to the classification effect on the slope of the raw material deposited in the hopper, and the coarse-grained raw material is more likely to roll than the fine-grained raw material, so that particle size segregation occurs in the hopper.

  When the raw material finally segregated in the lower hopper is charged into the furnace using a chute or the like, the particle size of the discharged raw material becomes large from the initial stage to the middle stage and becomes small at the end stage. Distribution.

  Ventilation management is important for stable operation of a blast furnace, and it is directed to a sharp central flow and moderate furnace wall flow. When charging from the side to the center side in sequence, the coarse raw material is deposited from the furnace wall to the middle part, and the fine raw material is deposited in the central part. As a result, it becomes difficult for gas to flow to the center, and excessive gas flows to the furnace wall, which greatly hinders stable operation of the blast furnace. Moreover, since the raw material particle size distribution in the radial direction in the furnace becomes nonuniform, it becomes difficult to control the gas flow distribution in the furnace only by the raw material charging amount.

In order to eliminate the non-uniformity of the discharged raw material particle size distribution at the time of raw material charging when using the center-feed type bell-less charging device as described above, a hollow cylinder is arranged in the lower hopper to A technology for changing the distribution of the discharged particle size when discharging to a “flat pattern, no particle size change” (see, for example, Patent Document 2 and Patent Document 3), and a plurality of ports connecting the upper hopper and the lower hopper In some cases, there is a technique for controlling the discharge particle size distribution by providing a time difference in the timing of opening each port (for example, see Patent Document 4).
JP 58-58211 A Japanese Patent Laid-Open No. 61-157604 JP-A-6-33122 JP 2005-154867 A

  Although the techniques of Patent Documents 2 to 4 are excellent techniques, in the method described in Patent Document 2, at least a device for vertically moving the hollow cylinder in the lower hopper, a structure for closing the upper end opening of the hollow cylinder, and a hollow cylinder A device for closing the upper end opening is required, the hopper structure is very complicated, and maintenance is also a problem.

  In Patent Document 3, the above structure is aimed to be simplified, but it is effective only when there is one port connecting the upper hopper and the lower hopper. In the raw material charging apparatus having a plurality of ports, Lacks effectiveness.

  In addition, the method described in Patent Document 4 in the raw material charging apparatus having a plurality of ports is a technique for controlling the discharge particle size by changing the timing of opening each port, and is an excellent technique that does not require major modification of equipment. As a whole, variation in the discharge particle size distribution remains, and as shown in FIG. 4, the raw material tends to become finer at the end of discharge, so further homogenization is desired. In addition, since the raw material charging time from the upper hopper to the lower hopper increases as a result of shifting the opening order of the ports, this technology can be used when it is desired to shorten the raw material charging time by increasing the operating rate. Is not desirable.

  Further, in the above-described conventional technology, there is a problem that maintenance frequency of the lower hopper is high because liner wear of the lower hopper due to direct hit of the raw material from the upper hopper is severe.

  Accordingly, an object of the present invention is to solve such problems of the prior art, and to load raw materials into a blast furnace using a center feed type raw material charging apparatus having an upper hopper and a lower hopper connected by a plurality of ports. It is an object of the present invention to provide a raw material charging apparatus and a raw material charging method for a bell-less blast furnace capable of accurately controlling the particle size distribution of discharged raw materials and preventing liner wear of a lower hopper.

The features of the present invention for solving such problems are as follows.
(1) Using the upper hopper and the lower hopper connected by a plurality of ports, the raw material in the upper hopper is transferred to the lower hopper via the port by opening and closing the port, and the lower hopper It is a raw material charging device for charging the raw material in the blast furnace, the same number of repulsion plates as the port is installed at each raw material falling position from the upper hopper in the lower hopper, the repulsion plate from the plate A bellless blast furnace raw material charging apparatus, comprising: a side wall for preventing the raw material from dropping; and an opening for dropping the raw material toward the outer periphery of the lower hopper.
(2) The raw material charging device for the bell-less blast furnace according to (1), wherein a repulsion plate is installed on a beam radially installed in the lower hopper in a horizontal section of the lower hopper.
(3) Using the apparatus described in (1) or (2), depositing the raw material falling from the upper hopper on the repulsion plate, and dropping a part of the deposited raw material from the opening of the repulsion plate A method for charging a raw material for a bell-less blast furnace, characterized by controlling the particle size distribution of the raw material deposited in the lower hopper and charging the raw material with the controlled particle size distribution from the center of the blast furnace to the periphery of the furnace .

  According to the present invention, in an existing raw material charging apparatus having two upper and lower hoppers connected by a plurality of ports, with a simple structure in which a rebound plate is installed at the lower part of the port in the lower hopper, at a low cost, When the raw material is charged from the upper hopper to the lower hopper, liner wear due to direct impact is prevented, the life of the lower hopper is extended, and the raw material accumulation shape in the lower hopper can be controlled. The discharge particle size distribution of the raw material can be controlled. As a result, the maintenance frequency of the lower hopper is suppressed, the control of the gas flow in the furnace is facilitated, and the blast furnace can be operated more efficiently.

  In the raw material charging apparatus used in the present invention, at least two hoppers of an upper hopper and a lower hopper are connected by a plurality of ports (tubes), and the raw material in the upper hopper is opened through the ports by opening the ports. When transferring to the hopper, the same number of repulsion plates as the ports are installed at each raw material dropping position from the upper hopper in the lower hopper. The rebound plate has a side wall that prevents the raw material from dropping from the plate, and an opening for dropping the raw material toward the outer periphery of the lower hopper is formed in a part of the side wall. Due to the presence of the repulsion plate, it is possible to prevent the liner of the lower hopper from being worn and to control the material deposition shape in the lower hopper. The raw material whose particle size distribution is controlled in the lower hopper is further charged into the blast furnace from the lower hopper.

  As such an apparatus, it is preferable to modify an existing facility called a vertical two-stage bellless charging apparatus. Such a modification can be carried out at low cost and can be easily applied to facilities in operation. Of course, the apparatus of the present invention can be installed when constructing a new facility.

  The shape of the rebound plate that has a side wall that prevents the raw material from dropping from on the plate and in which an opening for dropping the raw material toward the outer periphery of the lower hopper is formed in a part of the side wall is not particularly limited However, it is preferable that the raw material dropped on the rebound plate does not spill out except from the opening. Even in the case of spilling, a certain particle size distribution control effect can be obtained, but it is more effective that the raw material falls only from the opening. As for the size of the rebound plate, it is desirable that at least the area of the portion where the dropped raw material is deposited is equal to or larger than the projected area of the port diameter, and it is preferable that all the dropped raw material enters the side wall of the rebound plate. If the repulsion plate is larger than necessary, a large amount of raw material may be held on the repulsion plate and hinder the charging of the raw material. The height of the side wall is preferably high enough to prevent the raw material on the repulsion plate from spilling from the side wall portion, and high enough to allow the rebound plate having the side wall to be installed in the hopper. The size of the opening is preferably set according to the amount of raw material charged and the particle size distribution of the raw material deposited on the lower hopper. It is preferable to adopt a variable structure in which the direction and size of the opening can be adjusted.

  Using the above-described raw material charging apparatus of the present invention, the raw material falling from the upper hopper is deposited on the repulsion plate, and a part of the accumulated raw material is deposited in the lower hopper by dropping from the opening of the repulsion plate. The particle size distribution of the raw material is controlled, and the raw material with the controlled particle size distribution can be charged into the blast furnace. The raw material that has fallen on the rebound plate accumulates to some extent as it is, but if a slope with an angle greater than the angle of repose is formed, it collapses and falls to the lower hopper from the opening. Since the newly falling raw material falls on the deposited raw material, it is possible to prevent the rebound plate from being worn.

  As the repulsion plate, a box shape, a spherical shape, a cylindrical shape, a triangular prism shape, a shape in which an upper part of an n-corner shape (n ≧ 4) is open, and the like can be considered. One embodiment of such a repulsion plate is shown in FIG.

  In FIG. 1, (a) is a perspective view from above of the repulsion plate, (b-1) is a perspective view of a state in which the dropped raw material is deposited on the repulsion plate, and (b-2) is a side view thereof. The box-type rebound plate is formed from a rebound plate main body 10a and side walls 10b, 10c, and 10d, and a portion 10e having no side wall is an opening. By installing the opening 10e so as to face the outer periphery of the hopper, the falling raw material can be temporarily held on the rebound plate main body 10a and dropped in a specific direction. In FIG. 1 (b), the thick arrow indicates the flow direction of the raw material, the raw material deposited on the rebound plate body 10a forms the raw material deposition surface 11 according to the angle of repose, and the raw material dropped on the raw material deposition surface 11 is According to the raw material deposition surface 11, it falls toward the outer periphery of the hopper. In FIG. 1, when the heights of the side walls 10b, 10c, and 10d are set as high as possible within the range where there is no problem in the apparatus, the material spillage from other than the opening 10e is reduced, and the effect is great. In addition, in FIG. 1, the case where the repulsion board main body 10a is horizontal is illustrated, However, The repulsion board main body 10a may be in the state inclined. In that case, it is preferable to make the inclination which made the inner side high. However, if the inclination becomes too large, the effect of the invention is reduced, so the upper limit is about the raw material deposition surface 11 corresponding to the angle of repose of the raw material.

  The rebound plate may be installed in the lower hopper as appropriate by placing a beam, etc., at the position where the raw material falls from each port, but it is installed on the beam installed radially in the lower hopper in the horizontal section of the lower hopper. It is preferable. It is preferable to form a recess for holding the dropped material on the upper surface of the beam. Wear of the beam can be prevented by the raw material deposited in the depression.

  FIG. 2 shows an embodiment of the apparatus of the present invention, and is a schematic view of a longitudinal section when the bottom surface of the upper hopper and the top of the lower hopper are connected by four ports. A turning chute 2 is installed at the top of the upper hopper 1, and the raw material charged from the top inlet of the upper hopper 1 is charged toward the side wall in the upper hopper 1 using a charging belt conveyor 3 or the like. The port 4 has a gate portion 5 that can be opened and closed by a mechanism such as a seal valve. After the raw material is transferred into the lower hopper 6, the pressure inside the hopper is increased to the same level as the pressure in the furnace, and then the lower discharge port 7 is opened and charged into the blast furnace 9 using a distribution chute 8 that rotates and rotates. The raw material is charged while controlling the position. And in the lower hopper 6, it has the side wall which prevents the fall of the raw material from a board | plate in the fall position of the raw material from each port 4, and in order to make a raw material fall toward the outer periphery of a lower hopper in a part of side wall The repulsion plate 10 in which the opening is formed is installed. FIG. 3 is a top view of the lower hopper portion of FIG. 2 and shows a state where the opening 10e of the repulsion plate 10 is installed toward the outer periphery of the hopper.

  By using the above apparatus, the particle size distribution of the raw material charged into the blast furnace has a remarkable tendency to coarsen at the initial stage and fine at the end. In the present invention, a method is used in which the raw material having such a particle size distribution is charged from the center of the blast furnace to the periphery of the furnace.

  An embodiment of the present invention using the apparatus of FIGS. 2 and 3 will be described. The raw material charged from the top charging port of the upper hopper 1 using the charging belt conveyor 3 is charged into the upper hopper 1 by the turning chute 2. When the port 4 is opened, the raw material in the upper hopper 1 drops and is transferred to the lower hopper 6. At this time, the repulsion installed below the upper hopper exit side of each port 4 connecting the upper hopper 1 and the lower hopper 6. The plate 10 can prevent the raw material from directly hitting the lower hopper, and can control the deposition shape of the raw material falling to the lower hopper. Here, the repulsion plate 10 installed below the upper hopper exit side has a structure that prevents the raw material from falling from the side wall and causes the raw material to fall from the opening toward the outer periphery of the lower hopper. Note that the direction toward the outer circumference means that the raw material falls to a position closer to the outer circumference (side wall) of the lower hopper than the position where the raw material falls directly from the port.

  After the raw material in the upper hopper 1 is transferred into the lower hopper 6, the gate 5 of the port 4 is closed, the pressure in the lower hopper 6 is increased to the same level as the pressure in the blast furnace 9, and the lower discharge port 7 is opened. Then, the raw material is charged into the blast furnace 9 by the distribution chute 8. When charging the raw material into the blast furnace 9, the center of the furnace is also provided around the furnace wall while adjusting the mass of the charged raw material by adjusting the angle (tilt angle) of the distribution chute 8 with respect to the vertical direction and turning. It is also possible to charge the battery. Usually, the charging method is used in which the raw material is charged around the furnace wall, the tilt angle is changed stepwise while turning the distribution chute, and the latter half is charged in the center of the furnace. In the conventional charging method as shown in FIG. 4, relatively coarse particles are discharged at the beginning of discharge and fine particles are discharged at the end of discharge, so that coarse particles are charged around the furnace wall and fine particles are charged at the center. Therefore, there is a demerit that the flow around the furnace wall becomes stronger, the heat loss increases, and the ventilation in the blast furnace deteriorates due to the collapse of the central flow. Therefore, in the present invention, first, a raw material is charged into the furnace center, the tilt angle is changed stepwise while turning the distribution chute, and in the latter half, a charging method of charging around the wall is used. As a result, fine particles are charged around the furnace wall, and coarse particles are charged at the center. By using the charging device with the repulsion plate 10, when the raw material is charged from the upper hopper 1 to the lower hopper 6, the liner wears on the inner wall of the lower hopper 6 due to the direct hit of the raw material, and the lower hopper has a long life. The discharge particle size distribution of the raw material charged into the furnace by controlling the raw material accumulation shape in the lower hopper 6 is suitable for the method of charging from the furnace center portion of the blast furnace to the furnace peripheral portion. Controlled by distribution.

  Even when all the raw materials are charged into the lower bunker, it is preferable to install the repulsion plate 10 at a position where it is not buried in the raw material because the effect of changing the flow direction of the falling raw material is always maintained. It is preferable to check the relationship between the installation height of the rebound plate 10 and the discharge particle size distribution to the blast furnace in advance to determine the optimum rebound plate installation height according to the operating conditions. The installation height of the repulsion plate 10 varies depending on the mass of the charged raw material, the bulk density, etc. according to the capacity of the hopper to be used and the operation status.

  By installing the repulsion plate 10, it is possible to avoid a direct hit to the liner of the lower hopper when transferring the raw material from the upper hopper to the lower hopper, and the amount of liner wear is reduced. As the maintenance work of the input device, it is only necessary to replace the repulsion plate 10, and there is an effect that both workability and work time at the time of resting are improved.

  Similar to the apparatus shown in FIGS. 2 and 3, a facility in which four box-shaped rebound plates having a cubic shape with an opening at the top and one side are installed below the upper hopper exit side of the port connecting the upper hopper and the lower hopper. The particle size distribution of the discharged raw material was measured when charging the raw material into the blast furnace. The opening of the rebound plate was oriented toward the outer periphery of the hopper. The rebound plate was installed in a cross-shaped beam in the lower hopper. FIG. 4 shows the discharge particle size distribution from the lower hopper when the conventional technique is used, and FIG. 5 shows the discharge particle size distribution from the lower hopper when the rebound plate is installed. In FIG. 5, the hatched range is the range of variation in particle size in the case of the prior art shown in FIG. 4. According to FIG. 5, it can be seen that a flat discharge particle size distribution is formed by the installation of the repulsion plate as compared with the prior art. Further, when attention is paid to the range of the discharge particle size of 0.9 to 1.2, since the discharge end particle size tends to be reduced, when using the apparatus of the present invention, the distribution chute is sequentially moved from the center side of the blast furnace to the furnace wall side. By charging the raw materials while swirling each time, the raw material distribution in the blast furnace becomes a particle size distribution that forms a sharp central flow and an appropriate peripheral flow, and the operation of the blast furnace is further stabilized.

  In addition, when using the apparatus of the present invention, the raw material falling from the upper bunker does not directly hit the inner wall of the lower bunker, and the installed rebound plate itself is structurally very low in wear, so the raw material charging device The maintenance frequency of was reduced.

Schematic of one embodiment of a rebound plate used in the present invention. (A) Perspective view from above, (b-1) Perspective view with raw material deposited on rebound plate, (b-2) Side view Schematic which shows one Embodiment of the raw material charging device of this invention. FIG. 3 is a top view of the lower part of FIG. 2. The graph which shows the discharge raw material particle size distribution from a raw material charging device (conventional example). The graph which shows the discharge raw material particle size distribution from a raw material charging device (invention example). The figure which shows an example of a center feed type bell-less charging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper hopper 2 Turning chute 3 Loading belt conveyor 4 Port 5 Gate part 6 Lower hopper 7 Lower discharge port 8 Distribution chute 9 Blast furnace 10 Repulsion plate 10a Repulsion plate main body 10b, c, d Side wall 10e Opening part 11 Raw material deposition surface

Claims (3)

  Using the upper hopper and the lower hopper connected by a plurality of ports, the raw material in the upper hopper is transferred to the lower hopper via the port by opening and closing the port, and the raw material in the lower hopper is transferred to the lower hopper. A raw material charging device for charging a blast furnace, wherein the same number of repulsion plates as the ports are installed at the respective raw material dropping positions from the upper hopper in the lower hopper, and the repulsion plates drop the raw material from the plate. A bellless blast furnace raw material charging apparatus, characterized in that an opening for dropping the raw material toward the outer periphery of the lower hopper is formed in a part of the side wall.   2. The raw material charging apparatus for a bell-less blast furnace according to claim 1, wherein a repulsion plate is installed on a beam radially installed in the lower hopper in a horizontal section of the lower hopper.   The apparatus according to claim 1 or 2, wherein a raw material falling from an upper hopper is deposited on a repulsion plate, and a part of the accumulated raw material is dropped from an opening of the rebound plate, thereby lower hopper A raw material charging method for a bell-less blast furnace, comprising controlling a particle size distribution of a raw material deposited therein and charging the raw material with the controlled particle size distribution from a furnace central portion to a furnace peripheral portion.

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