Apparatus for manufacturing raw materials for blast furnace and method for manufacturing raw materials for blast furnace

Abstract

To provide apparatus and method for manufacturing a raw material for a blast furnace by which it is possible to enhance quality and productivity of the raw material for the blast furnace, such as ferro coke.SOLUTION: An apparatus for manufacturing a raw material for a blast furnace manufactures the raw material for the blast furnace by carbonizing a charged material including a carbon-containing material charged into a pyrolysis furnace 1. The apparatus includes a recovery device 90 that recovers powder in the carbon-containing material charged into the pyrolysis furnace 1 by absorbing the powder in the interior of the pyrolysis furnace 1.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an apparatus for manufacturing raw materials for a blast furnace used in a blast furnace such as formed coke, particularly ferrocoke, and a method for manufacturing raw materials for a blast furnace.

Background Art

[0002] In recent years, from the perspective of global warming, the steel industry has been required to reduce the amount of CO2 gas generated. For this reason, reducing the use of fossil fuels has become an urgent task. In the steel industry, hot metal is produced by reducing iron ore with carbon (coke produced by carbonizing coal in a coke oven) in a blast furnace. And, in order to reduce the coke unit consumption, the development of a technology using ferrocoke as a raw material for a blast furnace has been carried out. Ferrocoke is obtained by mixing a certain amount of iron ore with coal, forming it into lumps, and then subjecting it to carbonization treatment to disperse fine metallic iron particles in the coke. It is a formed coke whose reactivity of coke is enhanced by the catalytic action of metallic iron.

[0003] As a method for carbonizing ferrocoke, a method using a vertical carbonization furnace has been proposed. Patent Document 1 discloses a vertical carbonization furnace having a carbonization zone at the upper part and a cooling zone at the lower part. The method for manufacturing ferrocoke in a vertical carbonization furnace includes a charging step of charging a formed product composed of a carbon-containing substance and an iron-containing substance into the vertical carbonization furnace using a charging device, a carbonization step of blowing a heating gas into the carbonization zone and carbonizing the formed product to produce ferrocoke, a cooling step of cooling the ferrocoke by blowing a cooling gas into the cooling zone, a furnace gas discharging step of discharging the furnace gas from the discharge port at the top of the vertical carbonization furnace, and a ferrocoke discharging step of discharging the ferrocoke from the lower part of the cooling zone.

[0004] In the carbonization step, the formed product is heated by blowing a low-temperature gas from a low-temperature gas blowing port in the middle part of the carbonization zone and a high-temperature gas from a high-temperature gas blowing port in the lower part of the carbonization zone into the furnace. In the cooling step, the ferrocoke is cooled by blowing a cooling gas from a cooling gas blowing port in the lower part of the cooling zone.

[0005] Here, in order to increase the production amount of ferrocoke, it is necessary to increase the volume of the vertical retort furnace. Generally, the charged material is charged in an inclined direction using an inclined charging chute, and the heating gas and the cooling gas are injected in the depth direction of the vertical retort furnace (parallel to the horizontal component of the charging direction of the charged material). Therefore, in order to allow the gas to penetrate to the central part of the furnace, it is necessary to keep the inner dimension in the depth direction below a certain level. Thus, the vertical retort furnace is configured to have a longer inner dimension in the furnace width direction (the direction orthogonal to the depth direction in the cross section of the retort furnace) than in the depth direction, so as to secure a large volume.

[0006] Further, Patent Document 2 discloses a method of radially dispersing a material by providing a dispersion guiding portion having an inclined surface that slopes radially downward from the central portion in the width direction of the transport path to the outlet side as a method of uniformly charging (transporting) the material.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] The molded article is supplied to the retort furnace via a chute. At this time, the molded article breaks due to colliding with the wall surface of the chute or the like, and a part of it becomes powder. That is, the molded article contains granular materials and powders having a volume smaller than that of the granular materials.

[0009] The powder settles through the gaps between the granular materials. Therefore, the formed product is supplied to the retort furnace in a state separated into two layers, a granular material layer (upper layer) and a powder layer (lower layer). In other words, the granular material layer is supplied to the retort furnace in a state positioned above the powder layer. Therefore, when the granular material is supplied from the chute to the retort furnace, it is deposited farther away from the powder, and the powder is deposited on the chute side.

[0010] When the formed product is supplied to the retort furnace, a slope of the deposit is formed according to the angle of repose. Therefore, when the powder reaches the slope of the deposit, it moves along the slope to the opening side of the chute and comes to rest. In particular, when the powder reaches above the slope of the deposit, the slope becomes steep, so the powder tends to move more toward the opening side of the chute. On the other hand, since the granular material moves farther than the powder, most of it reaches near the apex of the deposit. That is, the granular material is uniformly supplied to the slope of the deposit.

[0011] In this way, the granular material and the powder of the formed product tend to be deposited at biased positions in the retort furnace. Therefore, when the powder is deposited at a biased position, the air permeability of the region deteriorates more than that of other regions. In the region where the powder is deposited at a biased position, the supply amount of the heating gas decreases due to the deterioration of the air permeability, and defects such as poor carbonization may occur in the formed product supplied to the region.

[0012] Even if the bulk material guiding part described in Patent Document 2 is used when supplying the formed product to the retort furnace, it is not possible to suppress the deposition of such powder at a biased position. For this reason, improvement of the above problems is desired.

[0013] The present invention has been made to solve the above problems, and an object thereof is to provide a blast furnace raw material manufacturing apparatus and a blast furnace raw material manufacturing method capable of improving the quality and productivity of blast furnace raw materials such as ferrocoke.

Means for Solving the Problems

[0014] In order to achieve the above object, the present invention [1]A blast furnace raw material manufacturing apparatus for manufacturing blast furnace raw materials by carbonizing a charged material containing a carbon-containing substance charged into a carbonization furnace, the blast furnace raw material manufacturing apparatus having a recovery device for sucking and recovering powder among the charged materials charged into the carbonization furnace inside the carbonization furnace. [2]The recovery device is provided on a side wall portion of the carbonization furnace, above the top of a deposit composed of the charged material deposited in the carbonization furnace, in the blast furnace raw material manufacturing apparatus according to [1] above. [3]It is connected to a side wall portion at the furnace top of the carbonization furnace and further has a charging chute for charging the charged material into the carbonization furnace. The recovery device is a side wall portion below the charging chute among the side wall portions where the charging chute is provided, and at least a part of the recovery device overlaps with the charging chute when viewed in the vertical direction of the carbonization furnace, in the blast furnace raw material manufacturing apparatus according to [1] above. [4]It is connected to a side wall portion at the furnace top of the carbonization furnace and further has a charging chute for charging the charged material into the carbonization furnace. The recovery device is a side wall portion below the charging chute among the side wall portions where the charging chute is provided, and at least a part of the recovery device overlaps with the charging chute when viewed in the vertical direction of the carbonization furnace. The blast furnace raw material manufacturing apparatus according to [2] above. [5]The gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less, in the blast furnace raw material manufacturing apparatus according to [1] above. [6]The gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less, in the blast furnace raw material manufacturing apparatus according to [2] above. [7]The gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less, in the blast furnace raw material manufacturing apparatus according to [3] above. [8]The gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less, in the blast furnace raw material manufacturing apparatus according to [4] above. [9]It is provided in the charging chute and further has a charging gate for temporarily retaining the charged material, in the blast furnace raw material manufacturing apparatus according to [3] above.

[10] The blast furnace raw material manufacturing apparatus according to [4] above, further comprising a charging gate provided in the charging chute for temporarily retaining the charged material.

[11] A method for manufacturing a blast furnace raw material using the blast furnace raw material manufacturing apparatus according to any one of [1] to

[10] above.

Advantages of the Invention

[0015] According to the present invention, the powder among the molded particles and powder of the carbon-containing substance charged into the retort furnace is recovered, and the molded product is retorted in the retort furnace to produce a blast furnace raw material. Therefore, it becomes possible to improve the quality and productivity of the blast furnace raw material.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0017] Hereinafter, the present invention will be described through embodiments of the present invention by taking as an example the case of manufacturing ferrocoke, which is a kind of molded coke obtained by mixing a certain amount of iron ore with coal and forming it into lumps. Here, each drawing is schematic and may be different from the actual one. Further, the following embodiments illustrate devices and methods for embodying the technical idea of the present invention, and do not specify the configuration to the following ones. That is, various changes can be made to the technical idea of the present invention within the technical scope described in the claims.

[0018] Referring to FIG. 1, the configuration of a conventional vertical retort furnace 100 as a raw material manufacturing apparatus for a blast furnace will be described. FIG. 1 shows a side schematic view of the vertical retort furnace 100. In the following description, the "charged material" is not limited to the "formed article containing a carbon-containing substance and an iron-containing substance" for producing ferrocoke, and may also include a "formed article containing a carbon-containing substance". That is, any formed article containing at least a carbon-containing substance may be used. The "charged material" includes a "formed article" and "powder" attached to or separated from the "formed article". Further, the "raw material for blast furnace" means "coke" including ferrocoke.

[0019] The vertical retort furnace 100 has a charging chute 10, a charging gate 20, a diffusion section 30, and a retort furnace body 70. First, the charged material containing a formed article containing a carbon-containing substance (coal) and an iron-containing substance (iron ore) is supplied to the charging chute 10 provided above the retort furnace body. The charged material is temporarily accumulated inside the charging chute 10 (in the middle of the charging chute 10) by closing the charging gate 20 (refer to the dashed line in the figure). The charged material passes through the inside of the charging chute 10 toward the retort furnace body 70 when the charging gate 20 is opened (indicated by a solid line in the figure). The charged material is dispersed so as to spread inside the charging chute 10 by passing through the diffusion section 30 of the charging chute 10. After passing through the inside of the charging chute 10, the charged material accumulates inside the retort furnace body 70. The charged material forms a mountain shape according to the angle of repose inside the retort furnace body 70.

[0020] Here, as described above, the charged material charged into the retort furnace body 70 is separated into two layers, a formed article layer (upper layer) and a powder layer (lower layer), inside the charging chute 10 before reaching the retort furnace body 70. Therefore, as shown in FIG. 1, the charged material charged into the retort furnace body 70 falls inside the retort furnace body 70 while separating into the formed article layer 40 and the powder layer 50. For this reason, the charged material 60 accumulated inside the retort furnace body 70 is in a state where the formed article and the powder are unevenly distributed. Due to this uneven distribution, in the conventional vertical retort furnace 100, the gas flow inside the retort furnace body 70 becomes non-uniform, and problems such as poor carbonization of the formed article occur.

[0021] FIG. 2 is a side sectional view showing the top of the retort furnace 1 as a raw material manufacturing apparatus for a blast furnace according to the invention of the present application. As shown in FIG. 2, among the side wall portions 80 and 81 at the top of the retort furnace 1 facing each other in the depth direction S of the retort furnace 1, a charging chute 10 is connected to one side wall portion 80. A recovery device 90 is connected to the side wall portion 80 below the charging chute 10 in the side wall portion 80 and above the top DMtop of the molded product DM (hereinafter referred to as sediment) deposited inside the retort furnace 1. The recovery device 90 is configured to suck and recover the powder contained in the molded product charged into the retort furnace 1 from the charging chute 10. Specifically, a suction hole 91 penetrating the side wall portion 80 in the thickness direction is formed in the side wall portion 80, and the recovery device 90 is connected to the suction hole 91 via a suction pipe 92. The powder contained in the molded product will be described later.

[0022] As an example, the shape of the suction hole 91 may be circular or rectangular, and in the example shown here, it is rectangular. The other cross-sectional shapes of the suction pipe 92 may be cylindrical or square tube-shaped. The inner dimension of the suction hole 91 or the diameter of the inscribed circle of the suction hole 91, and the inner dimension of the suction pipe 92 or the diameter of the inscribed circle of the suction pipe 92 are set to be larger than the particle size of the powder so that the powder can move inside them. Also, the inner dimension of the suction hole 91 or the diameter of the inscribed circle of the suction hole 91, and the inner dimension of the suction pipe 92 or the diameter of the inscribed circle of the suction pipe 92 are preferably set to an inner diameter of about the particle size of the molded product, and more preferably set to an inner diameter of about 1.5 times the particle size of the molded product.

[0023] The gas flow rate in the suction hole 91 and the suction pipe 92 by the recovery device 90 is preferably set to 10 m / s or more and 22 m / s. When the gas flow rate is less than 10 m / s, there is a possibility that the powder cannot be sucked and recovered. When the gas flow rate is higher than 22 m / s, there is a possibility that the molded product will also be recovered in addition to the powder. Therefore, these are to be avoided. The recovery device 90 may be configured to suck the powder together with the gas inside the retort furnace 1 within the above-described gas flow rate range.

[0024] Further, it is preferable that the suction holes 91 are provided at positions where at least a part of the suction holes 91 and the charging chute 10 overlap each other in the width direction (not shown) of the carbonization furnace 1 when viewed from the vertical direction of the carbonization furnace 1. This is to surely suck and recover the powder in a falling state that is charged from the charging chute 10 into the interior of the carbonization furnace 1. Also, the number of suction holes 91 provided is not limited, but when a plurality of charging chutes 10 are provided in the carbonization furnace 1, it is preferable to provide at least one suction hole 91 for each charging chute 10. A plurality of suction holes 91 may be provided at regular intervals across the entire width of the charging chute 10 in the width direction (not shown) of the carbonization furnace 1.

[0025] Note that the recovery device 90 may be driven by a control device or an operator (not shown) and may be configured to stop its operation. Also, since the recovery device 90 sucks the powder together with the gas, a separation device (not shown) for separating and recovering the gas and the powder may be provided in the middle of the suction pipe 92. When the separation device is provided, the powder separated and recovered may be formed into a molded product by a molding device and charged into the interior of the carbonization furnace 1.

[0026] Next, the operation and effects of the raw material manufacturing apparatus for a blast furnace having the above-described configuration will be described with reference to FIG. 3. A batch of molded products is conveyed by a conveying device (not shown) to the charging chute 10 with the charging gate 20 closed. As described above, a part of the molded product becomes powder during the conveying process, and the powder moves to the lower side of the molded product through the gaps between the molded products. Therefore, in the charging chute 10, it is in a state of being separated into two layers, a molded product layer 40 and a powder layer 50.

[0027] Subsequently, the charging gate 20 is opened, and the molded article is charged into the interior of the retort furnace 1, which is located at a position lower than the charging chute 10. The opening of the charging gate 20 may be performed by an operator, or may be performed by providing an actuator for opening and closing the charging gate 20 and a control device (not shown in the figures respectively) for controlling the operation of the actuator. When the control device is provided, for example, the actuator may be driven to open the charging gate 20 at a preset time interval or triggered by a signal input from the outside to the control device.

[0028] Almost simultaneously with the opening of the charging gate 20, the suction by the recovery device 90 is started. The start of the suction by the recovery device 90 may be performed by an operator or a control device as described above. For example, the recovery device 90 may be driven by using the opening of the charging gate 20 as a trigger. The molded article that has passed through the charging gate 20 passes over the diffusion section 30, and thereby is dispersed so as to spread inside the charging chute 10 and charged into the interior of the retort furnace 1. At this time, since the molded article is charged from a position higher than the powder, it falls toward the side wall portion 81 side rather than the powder.

[0029] On the other hand, the powder falls toward the side wall portion 80 side. Since the recovery device 90 is driven, the powder that has fallen from the charging chute 10 is sucked and recovered by the recovery device 90 as shown in FIG. 3. Thereby, the deposition of the powder inside the retort furnace 1 is suppressed, and mainly the molded article is charged and deposited, and the deposit DM is formed. That is, inside the retort furnace 1, it is possible to prevent or suppress the powder from being biased and deposited on the charging chute 10 side. Therefore, it is possible to suppress the deterioration of the air permeability inside the deposit DM due to the powder being biased and deposited on the charging chute 10 side.

[0030] When a batch of the molded product is charged into the retort furnace 1, the charging gate 20 is closed, the communication state between the charging chute 10 and the retort furnace 1 is blocked, and the suction by the recovery device 90 is stopped. These operations may be performed by an operator as described above, or may be performed by a control device that controls the operating states of the charging gate 20 and the recovery device 90. Alternatively, the elapsed time since the charging gate 20 was opened may be measured by a timer (not shown), and when the elapsed time exceeds a preset time, the charging gate 20 may be closed and the suction by the recovery device 90 may be stopped.

[0031] Therefore, according to the raw material manufacturing apparatus for a blast furnace having the above-described configuration, the gas permeability becomes substantially uniform throughout the retort furnace 1, and variations in the degree of carbonization of the molded product and the molded product particles can be suppressed. As a result, variations in the quality of ferrocoke can be suppressed, high-quality ferrocoke can be obtained, and furthermore, the productivity of ferrocoke can be improved.

Example

[0032] Next, an example performed to confirm the operation and effect of the present invention will be described. In this example, a test apparatus simulating the raw material manufacturing apparatus for a blast furnace shown in FIG. 2 was used. The charging chute used was of the same shape as that installed in the raw material manufacturing apparatus for a blast furnace shown in FIG. 2. A recovery box regarded as a retort furnace was installed on the outlet side of the charging chute. Further, a suction hole of a recovery device configured substantially the same as the suction hole 91 of the above-described recovery device 90 was connected to the lower side of the portion of the side wall surface of the recovery box to which the charging chute was connected. That is, the recovery efficiency of the powder when charging a raw material containing a molded product and powder into the recovery box regarded as the retort furnace 1 was investigated.

[0033] 25 kg of raw materials containing molded products and powder were charged from the charging chute into the recovery box. During the charging of the raw materials, the gas in the recovery box and the powder charged from the charging chute were continuously sucked by the recovery device. The proportion of the powder in the raw materials charged into the recovery box was 10%, and the proportion of the molded products was 90%. In this example, for the sake of convenience, particles with a diameter of 20 mm or more were defined as "molded products", and particles with a diameter of less than 20 mm were defined as "powder".

[0034] Then, the gas flow rate in the suction pipe of the recovery device was changed, and the suction rate of the molded products and the removal rate of the powder by the recovery device were investigated respectively. After the charging of the raw materials into the recovery box was completed, the suction by the recovery device was stopped. The molded product suction rate was expressed as a percentage (mass%) of the value obtained by dividing the mass of the molded products sucked by the recovery device by the mass of the raw materials charged from the charging chute into the recovery box. The powder removal rate was expressed as a percentage (mass%) of the value obtained by dividing the mass of the powder removed by the recovery device by the mass of the raw materials charged from the charging chute into the recovery box.

[0035] Figure 4 is a diagram showing the correlation between the molded product suction rate and the powder removal rate and the gas flow rate in the recovery device. As shown in Figure 4, it was recognized that as the gas flow rate in the recovery device gradually increased from 0 m / s, the powder removal rate increased rapidly. When the gas flow rate was approximately 10 m / s or more, it was recognized that the increase in the powder removal rate became gentle compared with the case where the gas flow rate was less than 10 m / s. On the other hand, the molded product suction rate was 0% until the gas flow rate reached 22 m / s, but it was recognized that it increased rapidly when it exceeded this value. From this result, it can be seen that it is preferable to set the gas flow rate in the recovery device to 10 m / s or more and 22 m / s or less. In contrast, when the gas flow rate is less than 10 m / s, the powder cannot be recovered sufficiently, and when the gas flow rate is higher than 22 m / s, the recovered products by the recovery device will be mixed with the molded products, which is not preferable.

Explanation of symbols

[0036] 1 Retort furnace as a raw material manufacturing device for blast furnaces 10 Charging chute 20 Loading Gate 30 Diffusion Section 40 Molding Layer 50 Powder Layer 70 Carbonization Furnace Body 80, 81 Side Wall 90 Recovery Device 91 Suction Hole 92 Suction Pipe DM Deposit DMtop Top of Deposit

Claims

1. A raw material manufacturing apparatus for a blast furnace that manufactures a raw material for a blast furnace by carbonizing a charged material containing a carbon-containing material charged into a carbonization furnace, a recovery device that sucks and recovers powder among the charged materials charged into the carbonization furnace inside the carbonization furnace, and a charging chute that is connected to a side wall portion at the top of the carbonization furnace and charges the charged material into the carbonization furnace, wherein the recovery device is a side wall portion below the charging chute among the side wall portions provided with the charging chute, and at least a part of the recovery device overlaps with the charging chute when viewed from the vertical direction of the carbonization furnace. A raw material manufacturing apparatus for a blast furnace provided at a position.

2. The raw material manufacturing apparatus for a blast furnace according to claim 1, wherein the recovery device is provided on a side wall portion above the top of a deposit composed of the charged material deposited in the carbonization furnace among the side wall portions of the carbonization furnace.

3. The raw material manufacturing apparatus for a blast furnace according to claim 1, wherein the gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less.

4. The raw material manufacturing apparatus for a blast furnace according to claim 2, wherein the gas flow rate in the recovery device is 10 m / s or more and 22 m / s or less.

5. The raw material manufacturing apparatus for a blast furnace according to claim 1, further comprising a charging gate provided in the charging chute for temporarily retaining the charged material.

6. The raw material manufacturing apparatus for a blast furnace according to claim 2, further comprising a charging gate provided in the charging chute for temporarily retaining the charged material.

7. A method for manufacturing a raw material for a blast furnace, which manufactures a raw material for a blast furnace using the raw material manufacturing apparatus for a blast furnace according to any one of claims 1 to 6.

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