JP2008202082A - Apparatus for charging raw material into bell-less blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for charging raw materials into a bell-less blast furnace, capable of accurately controlling a grain size distribution of the discharged raw materials, when the raw materials are charged by using a center-feeding type raw material charging apparatus provided with an upper hopper and a lower hopper connected with single number or the plurality of ports. <P>SOLUTION: The apparatus for charging raw materials into a bell-less blast furnace is the raw material charging apparatus, wherein the raw materials in the upper hopper is carried into the lower hopper through the port by opening/closing the port by using the upper hopper 1 and the lower hopper 6 connected with the ports 4 and charged into the blast furnace, and a screen 10 composed of wire group arranged at intervals is installed at the raw material dropping-down position from the upper hopper, in the lower hopper. It is desirable that the screen is the group of concentric wires 11 and is arranged as the curving surface state in the vertical cross-sectional surface of the hopper, and the interval is widened from the upper part toward the lower part and from the center part toward the outer peripheral part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a raw material charging apparatus for a bell-less blast furnace having a center-feed type bell-less furnace top charging apparatus in which raw material hoppers are 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 there is little circumferential deviation and distribution can be made 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 (see, for example, Patent Document 4).
JP 58-58211 A JP 61-157604 A 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. Further, since the fineness of the fine particles at the end stage is only slightly improved, there is no significant change in the discharge particle size distribution as a whole, and the tendency to become fine at the end stage is the same, so further improvement 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 raising the operating rate. Is not desirable.

  Accordingly, an object of the present invention is to solve such a problem of the prior art, and to feed a raw material to a blast furnace using a center feed type raw material charging device including an upper hopper and a lower hopper connected by one or a plurality of ports. It is an object of the present invention to provide a raw material charging device for a bell-less blast furnace capable of accurately controlling the particle size distribution of the discharged raw material when charging.

The features of the present invention for solving such problems are as follows.
(1) Using an upper hopper and a lower hopper connected by a port, the raw material in the upper hopper is transferred into the lower hopper through the port by opening and closing the port, and the raw material in the lower hopper Of a bellless blast furnace characterized in that a screen consisting of a group of wires arranged at intervals in the raw material dropping position from the upper hopper in the lower hopper is installed. Raw material charging equipment.
(2) The screen in the lower hopper is made up of a collection of concentric wires, the wires are arranged in a curved shape curved in the longitudinal section of the hopper, and the interval of the wires is from the upper part toward the lower part, and The raw material charging device for a bell-less blast furnace according to (1), wherein the raw material charging device widens from the center toward the outer periphery.

  According to the present invention, in an existing raw material charging apparatus having two upper and lower hoppers connected by ports, regardless of the number of ports, the raw material from the upper hopper to the lower hopper can be obtained at a low cost with a simple structure. Reduces liner wear due to direct impact during charging, extends the life of the lower hopper, and controls the shape of the material accumulated in the lower hopper, and controls the particle size distribution of the material charged into the furnace It becomes possible. 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 one or a plurality of ports (tubes), and the raw material in the upper hopper is piped by opening the ports. When transferring to the lower hopper, the raw material accumulation shape in the lower hopper is controlled by a screen-type chute composed of a group of wires arranged at intervals in the lower hopper on the outlet side of the upper hopper, The raw material is charged into the blast furnace from the lower hopper, and it is preferable to modify and use an existing facility called a vertical two-stage bellless charging device. 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.

  As a screen-type chute consisting of a group of wires arranged at intervals, for example, straight wires are arranged in parallel in the direction perpendicular to the radial direction in the horizontal cross section of the hopper at the material dropping position from each upper hopper. Can be used. It is preferable that the wires arranged in parallel are arranged in a curved shape curved in the longitudinal section of the hopper, and the distance between the wires becomes wider from the upper part toward the lower part and from the central part toward the outer peripheral part. For example, the shape of each wire 11 described in FIGS. 1 and 2 described below is not a circle but a square.

  It is preferable that the screen-type chute comprising a group of wires arranged at intervals is a concentric wire group. The wires are preferably arranged in a curved shape in the longitudinal section of the hopper, and the distance between the wires is preferably wider from the upper part toward the lower part and from the center part toward the outer peripheral part.

  FIG. 1 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. A screen-type chute 10 is installed in the lower hopper 6 at the position where the raw material is dropped from each port 4. Each wire 11 constituting the screen chute 10 is arranged in a curved surface so that the distance between the wires increases from the upper part toward the lower part.

  FIG. 2 is a top view of the apparatus of FIG. 1 and shows the horizontal arrangement of the screen chute 10 in the lower hopper 6. The screen-type chute 10 formed from a group of concentric wires 11 arranged at intervals is arranged so that the interval of the wires 11 increases from the center toward the outer periphery.

  An embodiment of the present invention using the apparatus of FIGS. 1 and 2 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 to the side wall of the upper hopper 1 by the turning chute 2. When the charged raw material is deposited in the upper hopper 1, a slope is formed and rolling occurs, and coarse grains that are easy to roll are distributed more in the periphery of the upper hopper 1 and segregation occurs. 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 screen type installed below the upper hopper exit side of the port 4 connecting the upper hopper 1 and the lower hopper 6. By using the chute 10, fine particles fall on the center of the lower hopper 6 and coarse particles fall on the periphery, whereby the deposited shape of the raw material falling on the lower hopper can be controlled.

  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 the raw material is charged into the blast furnace 9, the central portion 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) with respect to the vertical direction of the distribution chute 8 and turning. It is also possible to charge the battery. Normally, the raw material is charged around the furnace wall, and the tilt angle is changed stepwise while turning the distribution chute, and the latter half is charged into the furnace center. For this reason, in the conventional charging method in which the screen-type chute 10 is not installed, relatively coarse particles are discharged at the beginning of discharge and fine particles are discharged at the end of discharge as shown in FIG. In addition, the introduction of fine particles in the center has a demerit that the flow around the furnace wall becomes stronger and heat loss increases, and the ventilation in the blast furnace deteriorates due to the collapse of the central flow. By installing the screen-type chute 10, when the raw material is charged from the upper hopper 1 to the lower hopper 6, liner wear on the inner wall of the lower hopper 6 due to the direct hit of the raw material is alleviated, and the lower hopper can be extended in life. At the same time, it is possible to control the raw material accumulation shape in the lower hopper 6, and thereby the discharge particle size distribution of the raw material charged into the furnace can be controlled.

  By adjusting the distance between the wires 11 of the screen-type chute 10, the particle size distribution of the raw material stacked in the lower hopper 6 can be optimized, so that it is preferable to change appropriately according to the operating conditions. The screen-type chute 10 is desirably installed at a relatively upper position of the lower bunker that is not buried in the raw material.

  Similar to the equipment shown in FIGS. 1 and 2, using a facility with a screen chute installed below the upper hopper exit side of the port connecting the upper hopper and the lower hopper, the particle size distribution in the lower hopper and the raw material in the blast furnace The particle size distribution of the discharged raw material when charging was measured.

  FIG. 4 shows the particle size distribution in the lower hopper when using conventional equipment without a screen-type chute, and FIG. 5 shows the particle size distribution when using the raw material charging apparatus with the screen-type chute according to the present invention. The particle size distribution in the hopper is indicated as 12 for coarse particles, 13 for medium particles, and 14 for fine particles. FIG. 6 shows the particle size distribution of the discharged raw material when the raw material charging apparatus provided with the screen chute of the present invention is used.

  In the case of using the prior art, as shown in FIGS. 3 and 4, a particle size distribution is formed in the lower hopper so that relatively coarse particles are discharged at the beginning of discharge and fine particles are discharged at the end of discharge. As shown in FIGS. 5 and 6, fine particles are discharged in the initial stage, and the particle size distribution is such that the final stage is coarse. Thereby, 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 stabilized.

Schematic which shows one Embodiment of the raw material charging device of this invention. FIG. 2 is a top view of the device of the present invention shown in FIG. 1. The graph which shows the particle size distribution of the discharge | emission raw material from a raw material charging device (prior art). The figure which shows the particle size distribution in the lower hopper at the time of using the conventional installation. The figure which shows the particle size distribution in the lower hopper at the time of using the raw material charging device of this invention. The graph which shows the particle size distribution of the discharge | emission raw material at the time of using the raw material charging device of this invention. 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 Screen type chute 11 Wire 12 Coarse grain 13 Medium grain 14 Fine grain

Claims (2)

  Using an upper hopper and a lower hopper connected by a port, the raw material in the upper hopper is transferred into the lower hopper through the port by opening and closing the port, and the raw material in the lower hopper is transferred to a blast furnace. A raw material charging apparatus for charging a bell-less blast furnace, characterized in that a screen comprising a group of wires arranged at intervals at a position where the raw material falls from the upper hopper in the lower hopper is installed. apparatus.   The screen in the lower hopper is composed of concentric wires, and the wires are arranged in a curved shape that is curved in the longitudinal section of the hopper, and the distance between the wires is from the upper part toward the lower part and from the center part. 2. The raw material charging device for a bell-less blast furnace according to claim 1, wherein the raw material charging device is widened toward the outer periphery.

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