Method and apparatus for manufacturing raw materials for blast furnace

Abstract

To provide a method and an apparatus for producing a raw material for a blast furnace such as ferrocoke in high quality and productivity.SOLUTION: A method of producing a molded product containing a carbon-containing substance and an iron-containing substance from a raw material for a blast furnace in a pyrolysis furnace comprises the steps of: charging the molded product from a furnace upper part of the pyrolysis furnace; measuring a height from a furnace top of the pyrolysis furnace to a peak of the deposited molded product; and suctioning gas of the furnace upper part, wherein a charging amount is preferably controlled so that a distance (D) from a position of a gas suction port to the peak of the deposited molded product is within a range of 200 to 700 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for manufacturing raw materials for a blast furnace, and more particularly to a method and an apparatus for manufacturing ferrocoke, which is formed coke.

Background Art

[0002] In blast furnace operation, coke produced by carbonizing coal in a coke oven is generally used. In recent years, a technique has been developed in which a certain amount of iron ore is mixed with coal, pelletized, and then carbonized to produce formed coke, ferrocoke, which is used as a raw material for a blast furnace in order to improve the reactivity of the coke. Among them, a method using a vertical carbonization furnace as a carbonization method of ferrocoke has been proposed. For example, Patent Document 1 discloses a manufacturing method using a vertical carbonization furnace having a carbonization zone in the upper part and a cooling zone in the lower part. This method for manufacturing ferrocoke has a charging step of first charging a formed product composed of a carbon-containing substance and an iron-containing substance into a vertical carbonization furnace. Next, it has a carbonization step of blowing a heating gas into the carbonization zone to carbonize the formed product and produce ferrocoke. Then, it has a cooling step of blowing a cooling gas provided in the cooling zone to cool the ferrocoke, and a step of discharging the in-furnace gas from the discharge port at the upper part of the furnace of the vertical carbonization furnace. Finally, it has a ferrocoke discharging step of discharging ferrocoke from the lower part of the cooling zone. In the carbonization step, a low-temperature gas is blown from a low-temperature gas injection tuyere in the middle part of the carbonization furnace, and a high-temperature gas is blown from a high-temperature gas injection tuyere in the lower part. Here, in order to increase the production amount of ferrocoke, it is necessary to increase the volume of the carbonization furnace. However, the cooling gas and the high-temperature gas are injected in the depth direction of the carbonization furnace (the direction from the gas injection side to the opposite side surface). Therefore, in order to penetrate to the central part in the furnace, the depth direction of the furnace cannot be made larger than a certain level. That is, the shape of the carbonization furnace needs to be a structure that is longer in the furnace width direction (the direction orthogonal to the depth direction) than in the depth direction.

[0003] On the one hand, Patent Document 2 discloses a ferro-coke production apparatus that provides a dispersion material having an inclined surface that widens downward on the outlet side of the charging chute as an apparatus for uniformly charging a molded product in the furnace width direction.

Prior Art Document

Patent Document

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, in a vertical retort furnace having a structure that is longer in the furnace width direction than in the depth direction (see FIG. 1 described later), even if multiple rows of inlets are arranged in the furnace width direction, it is difficult to install a sufficient number of inlets with respect to the furnace width length. And when limited inlets are installed, there is a problem that the charging distribution according to the angle of repose of the charged molded product (hereinafter also referred to as "charged material") is obtained, and a uniform charging shape cannot be obtained. Furthermore, when the molded product cannot be uniformly charged in the furnace width direction, locally high powder pressure areas are generated in the furnace, and due to the weight of the charged material, there is a possibility that the molded product will crack. Also, when there are areas with a large number and areas with a small number of molded products in the furnace width direction when the molded product is charged into the furnace, there is a problem that the gas flow in the furnace becomes non-uniform and affects the carbonization of the molded product.

[0006] On the other hand, although the apparatus of Patent Document 2 described above is disclosed as an apparatus for uniformly charging the charged material, fine powder is mixed in the charged material, and when charging in a state where fine powder is mixed, there is a problem that the strength of the molded product after carbonization varies, and it is difficult to obtain a molded product having sufficient strength.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a method and apparatus for producing blast furnace raw materials such as ferrocoke with high quality and high productivity.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the various problems described above, the present invention has found that when producing formed coke, in order to efficiently recover fine powder mixed in after charging by gas suction, the position of the gas suction port is related to the height of the charged material. Furthermore, it has been found that it is effective to control the charging amount while measuring the height of the charged material.

[0009] Based on such findings, the present invention has been further studied and completed, and the gist of the present invention is as follows. [1] In a method for producing blast furnace raw materials by carbonizing a formed product containing a carbon-containing substance and an iron-containing substance in a retort furnace, a step of charging the formed product from the upper part of the retort furnace (charging step); a step of measuring the height from the top of the retort furnace to the apex of the formed product deposited from the top of the retort furnace (measuring step); a step of sucking the gas from the upper part of the furnace (gas suction step); A method for producing blast furnace raw materials, characterized by comprising the above. [2] In the above [1], the charging step is characterized in that the charging amount of the formed product is controlled according to the charging height of the formed product obtained in the measuring step. A method for producing blast furnace raw materials. [3] In the above [1] or [2], in the charging step, the charging amount is controlled so that the distance (D) from the position of the suction port for sucking the gas to the apex of the formed product deposited is in the range of 200 mm to 700 mm. A method for producing blast furnace raw materials, characterized by this. [4] In the charging step according to any one of the above [1] to [3], further, a step of intermittently (intermittently) charging the formed product into the retort furnace is provided. A method for producing blast furnace raw materials, characterized by this. 〔5〕In the charging step according to any one of 〔1〕 to 〔4〕 above, the method for producing a raw material for a blast furnace further includes a step of charging while diffusing the molded product. 〔6〕In any one of 〔1〕 to 〔5〕 above, the gas suction step is characterized in that the gas is suctioned from a plurality of locations on the side surface of the retort furnace. The method for producing a raw material for a blast furnace. 〔7〕In an apparatus for producing a raw material for a blast furnace by carbonizing a molded product containing a carbon-containing substance and an iron-containing substance in a retort furnace, means (charging port) for charging the molded product from the upper part of the retort furnace; means (height measuring device) for measuring the height from the top of the retort furnace to the apex of the molded product deposited thereon; means (gas suction port) for sucking the gas at the upper part of the furnace; An apparatus for producing a raw material for a blast furnace, characterized by comprising the above. 〔8〕In 〔7〕 above, the charging means (charging port) has means (charging amount control device) for controlling the charging amount of the molded product according to the charging height of the molded product obtained by the measuring means (height measuring device). An apparatus for producing a raw material for a blast furnace. 〔9〕In 〔8〕 above, the charging amount control means (charging amount control device) is means for controlling the charging amount so that the distance (D) from the position of the gas suction port to the apex of the molded product deposited thereon is within the range of 200 mm to 700 mm. An apparatus for producing a raw material for a blast furnace. 〔10〕In any one of 〔7〕 to 〔9〕 above, the charging means (charging port) is further characterized in that an opening / closing gate is provided at the outlet of the charging port. An apparatus for producing a raw material for a blast furnace. 〔11〕In any one of 〔7〕 to 〔10〕 above, the charging means (charging port) is further characterized in that a diffusing portion is provided immediately below the outlet of the charging means (charging port). An apparatus for producing a raw material for a blast furnace. 〔12〕In any one of 〔7〕 to 〔11〕 above, the gas suction means (gas suction port) is provided at a plurality of locations on the side surface of the retort furnace. An apparatus for producing a raw material for a blast furnace.

Advantages of the Invention

[0010] In the production of formed coke, by sucking and removing fine powder together with furnace gas after charging into a vertical retort furnace, it becomes possible to relatively easily equalize the quality of the formed coke after carbonization, and excellent effects such as improved productivity are achieved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0012] Hereinafter, with reference to the drawings, embodiments of the method and apparatus for producing raw materials for a blast furnace according to the present invention will be described in detail, but the present invention is not limited thereto. Further, since the drawings are for conceptually explaining the present invention, the dimensions of the members shown and their ratios may be different from the actual ones.

[0013] [Steps (Procedures) of the Production Method] The production method according to the present invention is characterized by having the following steps in a method for producing raw materials for a blast furnace by carbonizing a formed product containing a carbon-containing substance and an iron-containing substance in a retort furnace. (1) Step of charging the formed product from the upper part of the retort furnace [Charging Step] (2) Step of measuring the height from the top of the retort furnace to the apex of the formed product deposited from the top of the furnace [Measurement Step] (3) Step of sucking the gas at the upper part of the furnace [Gas Suction Step] Hereinafter, the above steps will be described with reference to the drawings.

[0014] Figure 1 is a schematic perspective view of the upper part of a furnace showing an overview of a ferro-coke manufacturing apparatus (vertical retort furnace), which is an example of the manufacturing apparatus according to the present invention.

[0015] [Charging step] First, the charging step is a step of charging a molded product containing a carbon-containing substance (such as coal) and an iron-containing substance (such as iron ore), which are raw materials for ferro-coke, from a charging chute 1 provided in the upper part 5 of the retort furnace. The upper part 5 of the furnace refers to the upper structure of the retort furnace, which means the area from the furnace top of the retort furnace to the area where the molded product accumulates. The installation location of the charging chute 1 for charging the molded product is not particularly limited as long as it is within the upper part of the furnace.

[0016] Furthermore, in this charging step, it is preferable to provide either or both of the intermittent charging step and the molded product diffusion charging step described below.

[0017] [Intermittent charging step] The step of intermittently (intermittently) charging the molded product into the retort furnace is, for example, a method of providing an openable and closable gate 2 at the outlet side (the outlet of the charging port) of the charging chute 1 and intermittently charging the molded product into the furnace by opening and closing the gate 2. The reason for providing this step is to keep the pressure inside the retort furnace constant and to reduce the fluctuation of the gas concentration inside the furnace.

[0018] The molded product is charged into the upper part 5 of the retort furnace with fine powder mixed in. Before charging, the path of the molded product is closed by the gate 2, but when the gate 2 is opened from the closed state, the path of the molded product in the charging chute 1 is opened and charged. When the gate 2 is closed to close the path of the molded product, it is possible to store one batch (for example, 600 - 800 kg) of the molded product on the upstream side of the gate 2. In normal operation, the gate 2 is opened for each batch, and the molded product is charged. After each charging, it moves to a measuring step of measuring the height of the charged material.

[0019] [Molded product diffusion charging step] When charging, the step of charging while spreading the molded product specifically refers to a method of providing a diffusion part 3 in a square pyramid shape (pyramid shape) directly below the outlet side (the outlet of the charging port) of the charging chute 1 to spread. The reason for providing this diffusion charging step is that due to the shape of this diffusion part 3, the molded product to be charged spreads not only forward but also to the left and right during charging, so that the surface of the charged product becomes a more uniform shape.

[0020] [Measurement step] Subsequently, the measurement step is a step of measuring the distance from the top of the dry distillation furnace to the apex of the deposited molded product after charging (hereinafter, also referred to as "the height of the charged product" and represented by H).

[0021] Here, as a measuring device for measuring the height of the charged product, it is preferable to use a microwave level gauge. By using microwaves, an accurate distance can be measured even in a furnace environment where fine powders are mixed. In addition, a laser distance meter, a contact type distance meter, etc. can be mentioned.

[0022] Also, the amount of the molded product charged (charging amount) in the above-mentioned charging step is preferably controlled according to the height of the charged product (H) measured in this measurement step. The reason will be explained in the "Examination of the installation position of the gas suction port" described later.

[0023] [Gas suction step] Furthermore, the gas suction step is a step of sucking fine powders floating between the upper part of the furnace and the charged product together with the furnace gas after the molded product is charged. Here, the fine powders generally refer to those with an average particle diameter of 100 μm or less of the powders, but in the present invention, from the comparison with the molded product, those with an average particle diameter of less than 20 mm are defined as powders.

[0024] In order to suck the furnace gas, the gas is sucked by a suction pump (not shown) installed outside the furnace through a gas suction duct 7 from a gas suction port 6 provided on the side surface of the furnace wall of the upper part 5 of the furnace.

[0025] [Examination of the installation position of the gas suction port] Therefore, in order to control the charging amount and reduce the fine powder in the furnace, it is considered important to determine the position where the gas suction port is installed. A test examining the position of the gas suction port and the state of powder mixing will be described.

[0026] First, using a test apparatus (upper structure) 10 that mimics the manufacturing apparatus according to the present invention shown in Fig. 3, an examination regarding the appropriate installation position of the gas suction port 6 was conducted.

[0027] As the test raw material to be charged, a mixture of 90 wt% of a molded product and 10 wt% of powder was prepared. This test raw material was charged from the charging chute 1, gas suction was performed for a predetermined time, the charged material after gas suction was collected, and the weight ratio (powder ratio) of the powder in the charged material was confirmed. Then, the installation position of the gas suction port 6 during gas suction was changed, and the same charging test was conducted to confirm the respective powder ratios. Here, particles with an average particle diameter of 20 mm or more were regarded as the molded product, and particles with an average particle diameter of less than 20 mm were regarded as the powder as described above. The powder ratio was calculated from the weight ratio of the powder in the collected charged material.

[0028] The results are shown in Fig. 4. It was found that when the gas suction port was installed in the range of 200 mm to 700 mm downstream from the height of the charged material (the top of the charged material), the powder ratio of the charged material was reduced. More preferably, it is 400 mm to 700 mm.

[0029] From the above results, the present inventors found that in actual operation, it is difficult to change the installation position of the gas suction port according to the charging amount. Therefore, it is practical to operate from the perspective of how much of the charged material should be charged with respect to the installation position of the gas suction port.

[0030] That is, by controlling the charging amount while measuring the height position so that the height of the charged material is within the range of 200 mm to 700 mm upstream with respect to the position of the gas suction port, it becomes possible to efficiently discharge the powder contained in the charged material from the side of the furnace.

[0031] [Gas Suction Port and Suction Method] Next, the installation position of the gas suction port is preferably on both side surfaces opposite to the charging chute 1 side of the furnace body, and at the above-described height position. Also, it is preferably installed at a plurality of positions in the depth direction of the furnace (direction a in FIG. 1). For example, in the case of a furnace with two charging chutes 1 installed, three gas suction ports 6 are installed on the side surface on the charging chute 1 side, and three are also installed on the opposite side surface, for a total of six installations. By installing the gas suction ports 6 on the charging chute 1 side and the opposite side surface, the powder dispersed near the furnace wall can be efficiently recovered. Also, by installing the gas suction ports 6 in the depth direction of the furnace, powder can be recovered over the entire surface of the furnace interior. Furthermore, by installing at a plurality of positions in the furnace, the gas flow in the furnace becomes uniform, and ferrocoke having a uniform strength can be manufactured.

[0032] Note that the shape of the gas suction port is, for example, a rectangle with a length of 100 mm in the vertical direction and a width of 1000 mm in the horizontal direction. The interval between adjacent suction ports when a plurality are installed is, for example, 1200 mm.

[0033] Furthermore, at the inlet of the gas suction port, it is preferable to provide a filter (made of metal such as stainless steel, in a lattice shape or a slit shape, and the interval between the lattice or slits is about 10 mm) so that large-sized molded products are not sucked.

[0034] Also, as the ability to suck gas, it is preferable to suck only fine powder. For example, the suction speed is preferably set to 5 to 10 m / s. This is because if the suction speed is less than 5 m / s, sufficient suction ability cannot be obtained and fine powder is not sufficiently sucked, and if it exceeds 10 m / s, particles other than fine powder adhere to the filter part and the suction ability decreases. More preferably, it is 7 to 8 m / s.

[0035] [Ferrocoke production apparatus (retort furnace)] Here, the overall structure of the ferrocoke production apparatus (retort furnace) will be described. As described above, FIG. 1 is a schematic perspective view of the upper part of the production apparatus according to the present invention. This upper part of the furnace 5 is also referred to as a charging zone. The shape of the upper part of the furnace 5 is, for example, a depth a of 1.5 m and a furnace width b of 6 m. The overall height (total length) of the retort furnace is, for example, 28 m. As the overall structure of the retort furnace, it is composed of a charging zone, a carbonization zone, a cooling zone, and a discharge zone from the upper part. Below the charging zone, a carbonization zone 9 for heating and carbonizing the molded product is provided. This carbonization zone 9 is divided into two heating zones according to the heating temperature. The upper side (charging zone side) is a low-temperature zone (temperature range: 350 to 500 °C), and a high-temperature zone (temperature range: 700 to 850 °C) is provided below it. Tuyeres for blowing hot air are provided from the side surface of the furnace (the side opposite to the charging chute side) respectively. Further, a cooling zone for cooling the formed coke is provided below the carbonization zone 9, and a discharge zone for discharging the formed coke from the lower part of the furnace is provided after cooling.

Example

[0036] Hereinafter, embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0037] Using the production apparatus according to the present invention shown in FIG. 1, the relationship between the charging amount and the height position of the charged material was confirmed. For Samples No. 1 to 7 corresponding to the present invention examples, the charging amount of the molded product was controlled while measuring the height position of the charged material during charging, the gas in the furnace after charging was sucked, the formed coke after carbonization was sampled, and its strength was confirmed. Sample No. 8 corresponding to the comparative example is the case where gas suction is not performed without installing a gas suction port, and the strength of the formed coke was also confirmed. The suction speed of gas suction in this example was 8 m / s.

[0038] The strength of the sampled formed coke was measured by DI using the rotational strength test method described in JIS K 2151 150 15 and the average value, maximum value, and minimum value of the strength were obtained. Here, DI which is the strength (surface fracture strength) of the molded product 150 15It shows the mass ratio of the molded products of 15 mm or more after applying an impact of 150 rotations with a drum tester.

[0039] These results are shown in Table 1.

[0040]

Table 1

[0041] From the results in Table 1, it can be seen that in the case of Samples No. 1 to 7 (Examples of the present invention), compared with Sample No. 8 (Comparative Example) where gas suction is not performed, the average value of the strength is higher and the variation between the maximum value and the minimum value is smaller. Furthermore, when the charged material height position is controlled within the preferable range of 200 to 700 mm (in the case of Samples No. 1 to 4), it can be seen that the average strength is 75 or more and the variation between the maximum value and the minimum value is even smaller. As a result, it has become possible to manufacture high-quality molded products.

Explanation of Signs

[0042] 1 Charging chute 2 Gate 3 Diffusion part 4 Charged material 5 Upper part of furnace 6 Gas suction port 7 Gas suction duct 8 Charged material height measuring device 9 Carbonization zone 10 Test device (upper structure) a Depth b Furnace width H Distance from furnace top to charged material D Distance from charged material height position to gas suction port (center part)

Claims

1. In a method for producing a raw material for a blast furnace by carbonizing a molded product containing a carbon-containing substance and an iron-containing substance in a carbonization furnace, a step of charging the molded product from the upper part of the carbonization furnace [charging step]; a step of measuring the height from the top of the carbonization furnace to the apex of the molded product deposited from the top of the furnace [measurement step]; a step of sucking the gas at the upper part of the furnace [gas suction step]; and having, in the charging step, the charging amount of the molded product is controlled according to the charging height of the molded product obtained in the measurement step, in the charging step, the charging amount is controlled such that the distance (D) from the position of the suction port for sucking the gas to the apex of the molded product deposited is in the range of 200 mm to 700 mm. A method for producing a raw material for a blast furnace, characterized in that.

2. The method for producing a raw material for a blast furnace according to claim 1, further comprising a step of intermittently (intermittently) charging the molded product into the carbonization furnace in the charging step.

3. The method for producing a raw material for a blast furnace according to claim 1 or 2, further comprising a step of charging the molded product while diffusing the molded product in the charging step.

4. The method for producing a raw material for a blast furnace according to claim 1 or 2, wherein the gas suction step sucks from a plurality of locations on the side surface of the carbonization furnace.

5. The method for producing a raw material for a blast furnace according to claim 3, wherein the gas suction step sucks from a plurality of locations on the side surface of the carbonization furnace.

6. In an apparatus for producing a raw material for a blast furnace by carbonizing a molded product containing a carbon-containing substance and an iron-containing substance in a carbonization furnace, means for charging the molded product from the upper part of the carbonization furnace [charging port]; means for measuring the height from the top of the carbonization furnace to the apex of the molded product deposited from the top of the furnace [height measuring device]; means for sucking the gas at the upper part of the furnace [gas suction port]; and comprising, the charging port has means [charging amount control device] for controlling the charging amount of the molded product according to the charging height of the molded product obtained by the height measuring device, the charging amount control device is means for controlling the charging amount such that the distance (D) from the position of the gas suction port to the apex of the molded product deposited is in the range of 200 mm to 700 mm. An apparatus for producing a raw material for a blast furnace, characterized in that.

7. The apparatus for producing a raw material for a blast furnace according to claim 6, wherein the charging port is further provided with an openable and closable gate at the outlet of the charging port.

8. The manufacturing apparatus for raw materials for a blast furnace according to claim 6 or 7, wherein the charging port further comprises a diffusing portion immediately below the outlet of the charging port.

9. The manufacturing apparatus for raw materials for a blast furnace according to claim 6 or 7, wherein the gas suction ports are provided at a plurality of locations on the side surface of the retort furnace.

10. The manufacturing apparatus for raw materials for a blast furnace according to claim 8, wherein the gas suction ports are provided at a plurality of locations on the side surface of the retort furnace.

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