Blast furnace, tuyeres for blast furnace, and method for supplying reducing gas to a blast furnace.

Abstract

Disclosed is a new technology for suppressing deviations in the concentration distribution of a reducing gas in a furnace radial direction inside a blast furnace when supplying reducing gas to the inside of the blast furnace. One embodiment of the technology according to the present disclosure is a blast furnace having a hot-air tuyere, said blast furnace characterized in that: the hot-air tuyere has a tuyere body, a first reducing gas blow port, and a second reducing gas blow port; the tuyere body has a hot-air flow path; the first reducing gas blow port penetrates the wall of the tuyere body; and the second reducing gas blow port penetrates the wall of the tuyere body at a position different from that of the first reducing gas blow port.

Description

Technical Field

[0001] This application discloses a blast furnace, a tuyere for a blast furnace, and a method for supplying reducing gas to a blast furnace.

Background Art

[0002] In the ironmaking process, reduction of CO2 emissions has been considered. For example, when producing pig iron in a blast furnace, it may be possible to use a reducing gas such as hydrogen gas in place of a part of coke or the like as a reducing material. As a method for supplying reducing gas to a blast furnace, Patent Documents 1 and 2 disclose a method in which a lance for blowing reducing gas is disposed in a hot blast passage or a wall surface of a hot blast tuyere, and the reducing gas is blown through the lance. Although not assuming blowing of reducing gas, Patent Document 3 discloses a method in which a fuel injection lance is inserted into a wall surface of a hot blast tuyere, and pulverized coal as a fuel is blown into the blast furnace through the fuel injection lance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When supplying reducing gas into a blast furnace through a hot blast tuyere, a bias is likely to occur in the concentration of reducing gas in the furnace diameter direction inside the blast furnace.

Means for Solving the Problems

[0005] As means for solving the above problems, this application discloses the following multiple aspects. <Aspect 1> A blast furnace having hot air tuyeres, The aforementioned hot air nozzle The tuyere body and The first reducing gas injection port, The second reducing gas injection port, It has, The tuyeres body has a hot air passage, The first reducing gas injection port penetrates the wall of the tuyere body, The second reducing gas injection port penetrates the wall of the tuyere body at a different position from the first reducing gas injection port. Blast furnace. <Aspect 2> A blast furnace according to embodiment 1, Each of the outlets of the first reducing gas injection port and the second reducing gas injection port faces the hot air flow path. Blast furnace. <Aspect 3> A blast furnace according to embodiment 1 or 2, The height position P1 of the center of the outlet of the first reducing gas injection port is above the height position P2 of the center of the opening of the tuyere body. The height position P3 of the center of the outlet of the second reducing gas injection port is lower than the height position P2 of the center of the opening of the tuyere body. Blast furnace. <Aspect 4> A blast furnace according to any of the embodiments 1 to 3, The reducing gas supplied from the first reducing gas injection port and the second reducing gas injection port contains hydrogen gas. Blast furnace. <Aspect 5> A method for supplying reducing gas to a blast furnace, Hot air is supplied into the interior of the blast furnace through the hot air tuyeres of the blast furnace, Reducing gas is supplied into the blast furnace via a first reducing gas injection port that penetrates the wall of the tuyere body of the hot air tuyere, and a second reducing gas injection port that penetrates the wall of the tuyere body at a different location from the first reducing gas injection port. A method for supplying reducing gas to a blast furnace, including the supply of reducing gas. <Aspect 6> A method for supplying reducing gas to a blast furnace according to Aspect 5, Reducing gas is supplied from each of the outlets of the first reducing gas injection port and the outlet of the second reducing gas injection port into the hot air flow path of the tuyere body. A method for supplying reducing gas to a blast furnace. <Aspect 7> A method for supplying reducing gas to a blast furnace according to Aspect 5 or 6, The height position P1 of the center of the outlet of the first reducing gas injection port is above the height position P2 of the center of the opening of the tuyere body, The height position P3 of the center of the outlet of the second reducing gas injection port is below the height position P2 of the center of the opening of the tuyere body. A method for supplying reducing gas to a blast furnace. <Aspect 8> A method for supplying reducing gas to a blast furnace according to any one of Aspects 5 to 7, The reducing gas contains hydrogen gas. A method for supplying reducing gas to a blast furnace. <Aspect 9> A tuyere for a blast furnace, A tuyere body, A first reducing gas injection port, A second reducing gas injection port, Having, The tuyere body has a hot air flow path, The first reducing gas injection port penetrates the wall of the tuyere body, The second reducing gas injection port penetrates the wall of the tuyere body at a position different from the first reducing gas injection port. A tuyere for a blast furnace.

Advantages of the Invention

[0006] According to the technology of the present disclosure, when supplying reducing gas into the blast furnace, it is possible to suppress the deviation of the concentration of the reducing gas in the furnace diameter direction inside the blast furnace.

Brief Description of the Drawings

[0007] [Figure 1]This diagram provides a schematic example of a blast furnace configuration. Some components of the blast furnace are omitted from the diagram. [Figure 2A] This diagram schematically shows an example of the configuration of the tuyeres body, the first reducing gas injection port, and the second reducing gas injection port in a hot air tuyeres. The upper side of the paper corresponds to the furnace top side, and the lower side corresponds to the furnace bottom side. [Figure 2B] This diagram schematically shows an example of the configuration of the tuyeres body, the first reducing gas injection port, and the second reducing gas injection port in a hot air tuyeres. The upper side of the paper corresponds to the furnace top side, and the lower side corresponds to the furnace bottom side. [Figure 3A] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the first reducing gas injection port in a hot air tuyere. [Figure 3B] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the first reducing gas injection port in a hot air tuyere. [Figure 3C] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the first reducing gas injection port in a hot air tuyere. [Figure 3D] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the first reducing gas injection port in a hot air tuyere. [Figure 3E] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the first reducing gas injection port in a hot air tuyere. [Figure 4A] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the second reducing gas injection port in a hot air tuyere. [Figure 4B] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the second reducing gas injection port in a hot air tuyere. [Figure 4C] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the second reducing gas injection port in a hot air tuyere. [Figure 4D] This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the second reducing gas injection port in a hot air tuyere. [Figure 4E]This diagram schematically shows an example of the positional relationship between the opening of the tuyere body and the outlet of the second reducing gas injection port in a hot air tuyere. [Figure 5A] The simulation conditions are shown. [Figure 5B] The simulation conditions are shown. [Figure 5C] The simulation conditions are shown. [Figure 6A] This shows the hydrogen concentration distribution based on the simulation results. [Figure 6B] This shows the hydrogen concentration distribution based on the simulation results. [Figure 6C] This shows the hydrogen concentration distribution based on the simulation results. [Figure 7A] The simulation conditions are shown. [Figure 7B] The simulation conditions are shown. [Figure 7C] The simulation conditions are shown. [Figure 8A] This shows the hydrogen concentration distribution based on the simulation results. [Figure 8B] This shows the hydrogen concentration distribution based on the simulation results. [Figure 8C] This shows the hydrogen concentration distribution based on the simulation results. [Modes for carrying out the invention]

[0008] The following describes one embodiment of the blast furnace and the method for supplying reducing gas to the blast furnace according to this disclosure. However, the blast furnace and the method for supplying reducing gas to the blast furnace according to this disclosure are not limited to the following embodiment.

[0009] 1.Blast furnace As shown in Figure 1, a blast furnace 100 according to one embodiment has a hot air tuyere 10. As shown in Figures 2A and 2B, the hot air tuyere 10 has a tuyere body 11, a first reducing gas injection port 12, and a second reducing gas injection port 13. The tuyere body 11 has a hot air flow path 11a. The first reducing gas injection port 12 penetrates the wall of the tuyere body 11. The second reducing gas injection port 13 penetrates the wall of the tuyere body 11 at a different location from the first reducing gas injection port 12.

[0010] 1.1 Hot air nozzle As shown in Figure 1, the hot air tuyeres 10 are located, for example, below the lower end 101ax of the shaft of the blast furnace 100 and above the tapping port 102. The "lower end of the shaft" refers to the boundary between the shaft 101a and the furnace belly (belly) 101b. The "shaft" refers to the part above the furnace belly 101b, where the furnace diameter usually increases from top to bottom. The "furnace belly" refers to the part below the shaft and above the bellows (bosch) 101c, where the furnace diameter is usually the largest. The furnace diameter (diameter) of the furnace belly 101b may be, for example, 5m to 20m or 10m to 18m. The "tapping port" refers to the molten iron tapping port located at the bottom of the blast furnace 100. The "hot air tuyeres" refer to nozzles for supplying hot air to the blast furnace. The blast furnace 100 may have hot air tuyeres 10 located below the lower end 101bx of the furnace belly and above the taphole 102, or it may have hot air tuyeres 10 located below the lower end 101cx of the bellows and above the taphole 102.

[0011] The number of hot air tuyeres 10 provided in the blast furnace 100 is not particularly limited and can be determined according to the internal volume of the blast furnace. Multiple hot air tuyeres 10 may be arranged in the circumferential direction of the blast furnace 100. In other words, in the blast furnace 100, multiple hot air tuyeres 10 may be arranged in the circumferential direction when viewed from above. Typically, the height position P2 of the center of each of the multiple hot air tuyeres 10 is the same.

[0012] 1.1.1 Tuyere body The tuyeres body 11 is a hollow member having a hot air passage 11a. The upstream side of the hot air passage 11a of the tuyeres body 11 is connected to a blowpipe (not shown), and the downstream side of the hot air passage 11a faces the inside of the blast furnace 100. At the tip of the tuyeres body 11 facing the inside of the blast furnace 100, the tuyeres body 11 has an opening 11ax (hot air outlet) as the outlet for the hot air passage 11a. The tuyeres body 11 can be connected to a hot air furnace outside the blast furnace 100 via a hot air pipe, blowpipe, etc. In other words, the blast furnace 100 can be configured so that hot air is supplied to the inside of the blast furnace 100 from the hot air furnace via a hot air pipe, blowpipe, and tuyeres body 11. The opening diameter of the tuyeres body 11 (the circular equivalent diameter of the opening 11ax facing the inside of the blast furnace 100, the nozzle diameter) may be, for example, 20 mm or more and 400 mm or less, or 40 mm or more and 300 mm or less.

[0013] As shown in Figures 2A and 2B, the wall of the tuyere body 11 has, for example, an inner surface 11x facing the hot air passage 11a, and an outer surface 11y and end surface 11z facing the inside of the blast furnace 100. The first reducing gas injection port 12 and the second reducing gas injection port 13, which will be described later, are provided so as to penetrate the wall. The tuyere body 11 may have a cooling water passage inside the wall. This allows the tuyere body 11 and its surroundings to be cooled during the operation of the blast furnace 100, thereby suppressing thermal damage and the like. The tuyere body 11 is made of a known material, for example, copper.

[0014] 1.1.2 First reducing gas injection port The first reducing gas injection port 12 may be connected to an external reducing gas supply source 20 of the blast furnace 100 via a reducing gas supply channel 21 or the like. In other words, the blast furnace 100 may be configured so that reducing gas is supplied from the reducing gas supply source 20 to the inside of the blast furnace 100 via the reducing gas supply channel 21 and the first reducing gas injection port 12. There are no particular restrictions on the form of the reducing gas supply source 20 or the reducing gas supply channel 21.

[0015] As shown in Figures 2A and 2B, the first reducing gas injection port 12 is provided so as to penetrate the wall of the tuyere body 11. For example, the first reducing gas injection port 12 has a flow path 12a within the wall surface of the tuyere body 11, and an outlet 12ax downstream of the flow path 12a. The length, longitudinal shape, and opening shape of the flow path 12a of the first reducing gas injection port 12 can be appropriately determined in consideration of the thickness of the wall of the tuyere body 11 and the water cooling structure within the wall.

[0016] As shown in Figure 2A, the outlet 12ax of the first reducing gas injection port 12 may face the hot air flow path 11a. That is, the first reducing gas injection port 12 may supply reducing gas so as to merge with the hot air flow path 11a. Alternatively, as shown in Figure 2B, the outlet 12ax of the first reducing gas injection port 12 may be provided on the end face 11z of the tuyere body 11. That is, the first reducing gas injection port 12 may supply reducing gas into the blast furnace 100 independently of the hot air flow path 11a. According to the inventors' findings, in particular, as shown in Figure 2A, when the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 (described later) face the hot air flow path 11a (i.e., when reducing gas is supplied to the hot air flow path 11a from the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13), the concentration distribution of reducing gas in the radial direction inside the blast furnace 100 can be made more uniform. In this case, the distance from the center (centroid) of the downstream opening 11ax of the hot air flow path 11a to the center (centroid) of the outlet 12ax of the first reducing gas injection port 12 is not particularly limited. This distance may be, for example, 50 mm or more and 300 mm or less, or 70 mm or more and 150 mm or less.

[0017] The diameter (area circle equivalent diameter) of the outlet 12ax of the first reducing gas injection port 12 may be, for example, 10 mm or more and 50 mm or less, or 20 mm or more and 30 mm or less. Alternatively, the diameter of the outlet 12ax of the first reducing gas injection port 12 may be 10% or more and 50% or 15% or more and 30% or less of the diameter of the opening 11ax of the tuyere body 11. When the outlet 12ax has such a diameter, the flow rate of the reducing gas is easier to control.

[0018] 1.1.3 Second reducing gas injection port The second reducing gas injection port 13, like the first reducing gas injection port 12, may be connected to an external reducing gas supply source 20 of the blast furnace 100 via a reducing gas supply channel 21, etc. In other words, the blast furnace 100 may be configured so that reducing gas is supplied from the reducing gas supply source 20 to the interior of the blast furnace 100 via the reducing gas supply channel 21 and the second reducing gas injection port 13. There are no particular restrictions on the form of the reducing gas supply source 20 and the reducing gas supply channel 21. The reducing gas supply source 20 and the reducing gas channel 21 connected to the second reducing gas injection port 13 may be the same form as the reducing gas supply source 20 and the reducing gas channel 21 connected to the first reducing gas injection port 12 described above, or they may be of a different form.

[0019] Furthermore, the reducing gas supply source connected to the first reducing gas injection port 12 and the reducing gas supply source connected to the second reducing gas injection port 13 may be the same or different. That is, reducing gas may be supplied from one reducing gas supply source to the first reducing gas injection port 12 and the second reducing gas injection port 13 via a branched flow path, or reducing gas may be supplied from one reducing gas supply source to the first reducing gas injection port 12 and from a different reducing gas supply source to the second reducing gas injection port 13.

[0020] As shown in Figures 2A and 2B, the second reducing gas injection port 13 is provided at a different location from the first reducing gas injection port 12, and penetrates the wall of the tuyere body 11. For example, the second reducing gas injection port 13 has a flow path 13a within the wall surface of the tuyere body 11, and an outlet 13ax downstream of the flow path 13a. The length, longitudinal shape, and opening shape of the flow path 13a of the second reducing gas injection port 13 can be appropriately determined in consideration of the thickness of the wall of the tuyere body 11 and the water cooling structure within the wall.

[0021] As shown in Figure 2A, the outlet 13ax of the second reducing gas injection port 13 may face the hot air passage 11a. That is, the second reducing gas injection port 13 may supply reducing gas so that it merges with the hot air passage 11a. Alternatively, as shown in Figure 2B, the outlet 13ax of the second reducing gas injection port 13 may be provided on the end face 11z of the tuyere body 11. That is, the second reducing gas injection port 13 may supply reducing gas into the blast furnace 100 independently of the hot air passage 11a. As described above, when the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 face the hot air flow path 11a (i.e., when reducing gas is supplied to the hot air flow path 11a from the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13), the concentration distribution of reducing gas in the radial direction inside the blast furnace 100 can be made more uniform. In this case, the distance from the center (centroid) of the downstream opening 11ax of the hot air flow path 11a to the center (centroid) of the outlet 13ax of the second reducing gas injection port 13 is not particularly limited. This distance may be, for example, 50 mm or more and 300 mm or less, or 75 mm or more and 150 mm or less.

[0022] The diameter (area circle equivalent diameter) of the outlet 13ax of the second reducing gas injection port 13 may be, for example, 10 mm or more and 50 mm or less, or 20 mm or more and 30 mm or less. Alternatively, the diameter of the outlet 13ax of the second reducing gas injection port 13 may be 10% or more and 50% or 15% or more and 30% or less of the diameter of the opening 11ax of the tuyere body 11. When the outlet 13ax has such a diameter, the flow rate of the reducing gas is easier to control.

[0023] 1.1.4 Other reducing gas injection ports The hot air tuyere 10 may have other reducing gas injection ports in addition to the first reducing gas injection port 12 and the second reducing gas injection port 13. The form of the other reducing gas injection ports is not particularly limited. The number of other reducing gas injection ports provided in the hot air tuyere 10 may be one or more. The height position of the reducing gas injection ports provided in the hot air tuyere 10 is not particularly limited. The height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 and the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13 will be described later.

[0024] 1.2 Height position between the opening of the tuyere body and each air outlet As shown in Figure 3A, the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be above the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 12ax of the first reducing gas injection port 12 may be located directly above the center of the opening 11ax of the tuyere body 11. That is, the position of the center of the outlet 12ax of the first reducing gas injection port 12 in the circumferential direction of the blast furnace 100 may be the same as the position of the center of the opening 11ax of the tuyere body 11. Alternatively, the center of the outlet 12ax of the first reducing gas injection port 12 may be located diagonally above the center of the opening 11ax of the tuyere body 11. That is, in the circumferential direction of the blast furnace 100, the position of the center of the outlet 12ax of the first reducing gas injection port 12 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Figure 3B, when the opening 11ax of the tuyere body 11 is viewed from the front, the straight line L1 passing through the center of the opening 11ax and the center of the outlet 12ax may be inclined by an angle θ1 with respect to a vertical line L2 passing through the center of the opening 11ax. This angle θ1 may be, for example, between 0° and 45°. In Figure 3B, an example is shown in which the outlet 12ax is located on the left half of the tuyere body 11, but the outlet 12ax may also be located on the right half of the tuyere body 11.

[0025] As shown in Figure 3C, the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be lower than the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 12ax of the first reducing gas injection port 12 may be located directly below the center of the opening 11ax of the tuyere body 11. That is, the position of the center of the outlet 12ax of the first reducing gas injection port 12 in the circumferential direction of the blast furnace 100 may be the same as the position of the center of the opening 11ax of the tuyere body 11. Alternatively, the center of the outlet 12ax of the first reducing gas injection port 12 may be located diagonally below the center of the opening 11ax of the tuyere body 11. That is, in the circumferential direction of the blast furnace 100, the position of the center of the outlet 12ax of the first reducing gas injection port 12 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Figure 3D, when the opening 11ax of the tuyere body 11 is viewed from the front, the straight line L1 passing through the center of the opening 11ax and the center of the outlet 12ax may be inclined by an angle θ2 with respect to a vertical line L2 passing through the center of the opening 11ax. This angle θ2 may be, for example, between 0° and 45°. In Figure 3D, an example is shown in which the outlet 12ax is located on the left half of the tuyere body 11, but the outlet 12ax may also be located on the right half of the tuyere body 11.

[0026] As shown in Figure 3E, the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be the same as the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 12ax of the first reducing gas injection port 12 may be located directly to the side of the center of the opening 11ax of the tuyere body 11. In Figure 3E, an example is shown in which the outlet 12ax is located on the left half of the tuyere body 11, but the outlet 12ax may also be located on the right half of the tuyere body 11.

[0027] As shown in Figure 4A, the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13 may be above the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 13ax of the second reducing gas injection port 13 may be located directly above the center of the opening 11ax of the tuyere body 11. That is, the position of the center of the outlet 13ax of the second reducing gas injection port 13 in the circumferential direction of the blast furnace 100 may be the same as the position of the center of the opening 11ax of the tuyere body 11. Alternatively, the center of the outlet 13ax of the second reducing gas injection port 13 may be located diagonally above the center of the opening 11ax of the tuyere body 11. That is, in the circumferential direction of the blast furnace 100, the position of the center of the outlet 13ax of the second reducing gas injection port 13 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Figure 4B, when the opening 11ax of the tuyere body 11 is viewed from the front, the straight line L3 passing through the center of the opening 11ax and the center of the outlet 13ax may be inclined by an angle θ3 with respect to the vertical line L2 passing through the center of the opening 11ax. This angle θ3 may be, for example, between 0° and 45°. In Figure 4B, an example is shown in which the outlet 13ax is located on the left half of the tuyere body 11, but the outlet 13ax may also be located on the right half of the tuyere body 11.

[0028] As shown in Figure 4C, the height position P1 of the center of the outlet 13ax of the second reducing gas injection port 13 may be lower than the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 13ax of the second reducing gas injection port 13 may be located directly below the center of the opening 11ax of the tuyere body 11. That is, the position of the center of the outlet 13ax of the second reducing gas injection port 13 in the circumferential direction of the blast furnace 100 may be the same as the position of the center of the opening 11ax of the tuyere body 11. Alternatively, the center of the outlet 13ax of the second reducing gas injection port 13 may be located diagonally below the center of the opening 11ax of the tuyere body 11. That is, in the circumferential direction of the blast furnace 100, the position of the center of the outlet 13ax of the second reducing gas injection port 13 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Figure 4D, when the opening 11ax of the tuyere body 11 is viewed from the front, the straight line L3 passing through the center of the opening 11ax and the center of the outlet 13ax may be inclined by an angle θ4 with respect to the vertical line L2 passing through the center of the opening 11ax. This angle θ4 may be, for example, between 0° and 45°. In Figure 4D, an example is shown in which the outlet 13ax is located on the left half of the tuyere body 11, but the outlet 13ax may also be located on the right half of the tuyere body 11.

[0029] As shown in Figure 4E, the height position P1 of the center of the outlet 13ax of the second reducing gas injection port 13 may be the same as the height position P2 of the center of the opening 11ax of the tuyere body 11. For example, the center of the outlet 13ax of the second reducing gas injection port 13 may be located directly to the side of the center of the opening 11ax of the tuyere body 11. In Figure 4E, an example is shown in which the outlet 13ax is located on the left half of the tuyere body 11, but the outlet 13ax may also be located on the right half of the tuyere body 11.

[0030] The first reducing gas injection port 12 and the second reducing gas injection port 13 can each penetrate any position in the wall of the tuyere body 11 so that the outlets 12ax and 13ax do not interfere with each other. When the tuyere body 11 is divided into an upper half and a lower half, the outlet 12ax of the first reducing gas injection port 12 may be located in any position in the upper half and the outlet 13ax of the second reducing gas injection port 13 may be located in any position in the lower half, or both the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may be located in any position in the upper half, or both the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may be located in any position in the lower half. According to the inventors' findings, when the height positions of the respective outlets 12ax and 13ax are divided into upper and lower sections, the distribution of reducing gas concentration in the radial direction inside the blast furnace 100 can be made more uniform. In this regard, in one embodiment, the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be higher than the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13. For example, in one embodiment, the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be higher than the height position P2 of the center of the opening 11ax of the tuyere body 11, and the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13 may be lower than the height position P2 of the center of the opening 11ax of the tuyere body 11. In other words, when the tuyere body 11 is divided into an upper half and a lower half, the outlet 12ax of the first reducing gas injection port 12 may be located in one position in the upper half, and the outlet 13ax of the second reducing gas injection port 13 may be located in one position in the lower half. Alternatively, in one embodiment, when the tuyere body 11 is divided into an upper half and a lower half, both the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may be located in one position in the upper half, and the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be higher than the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13.Alternatively, in one embodiment, if the tuyere body 11 is divided into an upper half and a lower half, the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may both be located in one of the lower halves, and the height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be higher than the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13.

[0031] 1.4 Hot air The hot air supplied from the hot air tuyeres 10 into the blast furnace 100 may consist of, for example, air, or oxygen-enriched air. The temperature of the hot air is, for example, 1000°C or higher. The temperature of the hot air may be between 1000°C and 2000°C, between 1000°C and 1700°C, between 1000°C and 1500°C, or between 1000°C and 1300°C. The flow velocity of the hot air at the opening 11ax of the tuyeres body 11 may be adjusted as appropriate according to the operating conditions of the blast furnace 100, for example, between 100 m / s and 300 m / s, or between 200 m / s and 250 m / s.

[0032] 1.5 Reducing gas The reducing gas is a gas that functions as a reducing agent inside the blast furnace 100. That is, even if a gas does not function as a reducing agent before being supplied to the blast furnace 100, if it can generate a reducing agent (reducing component) inside the blast furnace 100 by thermal decomposition or other means, it is included in the term "reducing gas" as used in this application. Examples of such reducing gases include at least one selected from hydrogen gas, hydrocarbon gases (e.g., methane gas), carbon monoxide gas, ammonia gas, and alcohol gases (e.g., methanol gas and ethanol gas). In addition, in the technology of this disclosure, at least one selected from coke oven gas (COG), converter gas (LDG), blast furnace gas (BFG), natural gas (NG), and synthesis gas (Syngas) may be used as the reducing gas. These reducing gases may be used individually or in combination of two or more types. In particular, an even greater effect can be expected from the technology of this disclosure when the reducing gas includes hydrogen gas. The temperature of the reducing gas supplied to the inside of the blast furnace 100 from the first reducing gas injection port 12 and the second reducing gas injection port 13 may be, for example, 0°C to 2000°C or 25°C to 1500°C. In this embodiment, the flow velocity of the reducing gas at the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may be, for example, less than or equal to the speed of sound at the operating temperature of each reducing gas. For example, the flow velocity of the reducing gas at the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13 may be 100 m / s to 1000 m / s, and in particular, if it is 200 m / s to 800 m / s, the ventilation inside the blast furnace 100 will be stable, and the in-furnace reduction reaction will proceed stably.

[0033] 1.6 Other Gases Other gases may be supplied along with the reducing gas from the first reducing gas injection port 12 and the second reducing gas injection port 13. Examples of other gases include inert gases such as nitrogen gas.

[0034] 2. Method for supplying reducing gas to a blast furnace The technology disclosed herein also has an aspect as a method for supplying reducing gas to a blast furnace. That is, a method for supplying reducing gas to a blast furnace 100 according to one embodiment is: Hot air is supplied to the interior of the blast furnace 100 through the hot air tuyeres 10 of the blast furnace 100, Reducing gas is supplied to the inside of the blast furnace 100 via a first reducing gas injection port 12 that penetrates the wall of the tuyere body 11 of the hot air tuyere 10, and a second reducing gas injection port 13 that penetrates the wall of the tuyere body 11 at a different location from the first reducing gas injection port 12. Includes.

[0035] Details and preferred forms of the method for supplying hot air and reducing gas are as described above. For example, in the method for supplying reducing gas to the blast furnace 100 according to this embodiment, the reducing gas may be supplied to the hot air flow path 11a from the outlet 12ax of the first reducing gas injection port 12 and the outlet 13ax of the second reducing gas injection port 13. The height position P1 of the center of the outlet 12ax of the first reducing gas injection port 12 may be above the height position P2 of the center of the opening 11ax of the tuyere body 11, and the height position P3 of the center of the outlet 13ax of the second reducing gas injection port 13 may be below the height position P2 of the center of the opening 11ax of the tuyere body 11. The reducing gas may also contain hydrogen gas.

[0036] 3.Tuyere for blast furnace The technology disclosed herein also has aspects as a tuyere for a blast furnace. This blast furnace tuyere corresponds to the hot air tuyere 10 described above. That is, the blast furnace tuyere 10 according to one embodiment has a tuyere body 11, a first reducing gas injection port 12, and a second reducing gas injection port 13. Here, the tuyere body 11 has a hot air passage 11a, the first reducing gas injection port 12 penetrates the wall of the tuyere body 11, and the second reducing gas injection port 13 penetrates the wall of the tuyere body 11 at a different position from the first reducing gas injection port 12. Each component is as described above, and a detailed explanation is omitted here.

[0037] 4. Supplement In the operation of the blast furnace 100, for example, iron ore (iron oxide) and coke are charged into the blast furnace 100 from the top, hot air is supplied into the blast furnace 100 from a hot blast furnace outside the blast furnace 100 via hot air pipes and hot air tuyeres 10, reducing gas is supplied into the blast furnace 100 from a reducing gas supply source outside the blast furnace 100 via a reducing gas flow path and a first reducing gas injection port 12, and reducing gas is also supplied into the blast furnace 100 from a reducing gas supply source outside the blast furnace 100 via a reducing gas flow path and a second reducing gas injection port 13. The coke and other materials supplied into the blast furnace 100 are burned to generate reducing gas. The iron oxide is reduced and dissolved by the reducing gas produced by the combustion of the coke and other materials, and by the reducing gas supplied from the first reducing gas injection port 12 and the second reducing gas injection port 13, thereby obtaining molten pig. The molten iron is tapped out from a tapping port 102 located at the bottom of the blast furnace 100. In this embodiment, reducing gas is supplied to the inside of the blast furnace 100 via the first reducing gas injection port 12 and the second reducing gas injection port 13, thereby reducing the amount of carbon-containing reducing agent such as coke used. As a result, CO2 emissions can be reduced. The blast furnace 100 can take on various configurations as long as it is capable of producing pig iron as described above. For example, the blast furnace 100 may have other tuyeres, ports, or lances in addition to the hot air tuyere 10 described above. Furthermore, the hot air tuyere 10 may be equipped with other ports, lances, etc., in addition to the tuyere body 11, the first reducing gas injection port 12, and the second reducing gas injection port 13 described above. For example, the hot air tuyere 10 may be equipped with a pulverized coal injection lance, etc. Since the configuration of the blast furnace 100 other than the hot air tuyeres 10 is known in the art, a detailed explanation is omitted here.

[0038] 5. Effects As described above, according to this embodiment, the first reducing gas injection port 12 and the second reducing gas injection port 13 are used in combination as means for supplying reducing gas into the blast furnace 100, and reducing gas is supplied from multiple outlets 12ax and 13ax. Compared to the case where reducing gas is supplied from only one outlet, the concentration distribution of reducing gas in the radial direction inside the blast furnace 100 can be made more uniform.

[0039] Furthermore, when the first reducing gas injection port 12 and the second reducing gas injection port 13 are used in combination as a means of supplying reducing gas into the blast furnace 100, a larger amount of reducing gas can be supplied into the blast furnace 100 compared to when the reducing gas is supplied through a single system, and the supply of reducing gas can be more easily stabilized. Moreover, according to the inventor's findings, when reducing gas is supplied via a lance placed in the hot air passage 11a of the tuyere body 11, the combustion rate of the reducing gas in the hot air passage 11a tends to increase, and the melting and pressure loss of the tuyere tends to increase compared to when the reducing gas is supplied via a port penetrating the wall of the tuyere body 11 as described above.According to this embodiment, by combining the two ports, it is possible to supply a large amount of reducing gas and also to suppress the combustion of the reducing gas in the hot air passage 11a. [Examples]

[0040] The present invention will be further described below with reference to examples, but the present invention is not limited to the following examples. The present invention allows for the adoption of various conditions without departing from its gist and insofar as it achieves its objective. In the following examples, the case in which hydrogen gas is used as the reducing gas is illustrated, but the type of reducing gas is not limited thereto. In the examples shown below, the concentration of hydrogen molecules inside the blast furnace was evaluated by performing simulations that considered gas flow, heat transfer, and chemical reactions using the general-purpose thermal fluid analysis software FLUENT. At this time, the raceway region near the tuyeres was treated as a cavity without coke, and the coke-packed bed region inside the blast furnace away from the raceway was treated as a porous medium. A standard k-ε model was used for turbulence analysis, an eddy dissipation model for gas combustion, and Field's model for the gasification reactions of O2, CO2, and H2O in coke.

[0041] 1. When hydrogen gas is supplied via a single system Using simulation, (1) When hydrogen is supplied into the hot air flow path only through the hydrogen injection port that penetrates the lower wall of the tuyere body (Figure 5A) (2) When hydrogen is supplied into the hot air flow path only through the hydrogen injection port that penetrates the upper wall of the tuyere body (Figure 5B) (3) When hydrogen is supplied only from a hydrogen injection lance having an outlet inside the hot air passage of the tuyeres body (Figure 5C) For each of these, the hydrogen concentration distribution in the radial direction of the furnace was confirmed at a height of 12 m from the center of the tuyeres inside the blast furnace. The flow rate of hydrogen gas supplied from the port / lance was 2615 Nm³. 3 The value was set to / hr. Figure 6A shows the hydrogen concentration distribution in case (1) above, Figure 6B shows the hydrogen concentration distribution in case (2) above, and Figure 6C shows the hydrogen concentration distribution in case (3) above. The hydrogen concentration distribution was normalized by the average hydrogen mole fraction at a height of 12m from the center of the tuyeres.

[0042] As shown in Figures 6A to 6C, it can be seen that there are differences in the distribution of hydrogen concentration inside the furnace depending on the means and location of hydrogen gas supply. For example, in case (1) above, the hydrogen concentration is higher between the furnace wall and the center of the blast furnace. Also, in case (2) above, the hydrogen concentration is higher on the wall side and at the center of the blast furnace. Also, in case (3) above, the hydrogen concentration is higher near the furnace wall between the furnace wall and the center of the blast furnace. In other words, it is thought that by using multiple types of hydrogen gas injection means and / or blowing positions at the hot air tuyeres, the hydrogen concentration distribution in the radial direction inside the blast furnace can be averaged and made uniform. In particular, it is thought that by combining cases (1) and (2) above, that is, by using multiple hydrogen injection ports in combination, the hydrogen concentration distribution in the radial direction inside the blast furnace can be made even more uniform.

[0043] 2. When hydrogen gas is supplied through two separate systems. Using simulation, (4) When hydrogen is supplied into the hot air flow path from both the hydrogen injection port that penetrates the upper wall of the tuyere body and the hydrogen injection port that penetrates the lower wall of the tuyere body (Figure 7A) (5) For reference, see the case of (2) above (Figure 7B) (6) When hydrogen is supplied into the hot air passage from two hydrogen injection ports that penetrate the upper wall of the tuyere body (where, when the hot air passage outlet of the tuyere body is viewed from the front, the center of the outlet of one hydrogen injection port is located to the upper left (15° from directly above) relative to the center of the opening of the tuyere body, and the center of the outlet of the other hydrogen injection port is located to the upper right (15° from directly above) relative to the center of the opening of the tuyere body) (Figure 7C) For each of these, the hydrogen concentration distribution in the radial direction of the furnace was confirmed at a height of 12 m from the center of the tuyere inside the blast furnace. The flow rate of the supplied hydrogen gas was 4270 Nm³ in total for the two systems in the cases of (4) and (6) above. 3 Let / hr be used, and in the case of (5) above, only one system will be used for 4270Nm 3The value was set to / hr. Figure 8A shows the hydrogen concentration distribution in case (4) above, Figure 8B shows the hydrogen concentration distribution in case (5) above, and Figure 8C shows the hydrogen concentration distribution in case (6) above.

[0044] As shown in Figures 8A, 8B, and 8C, supplying hydrogen gas through two separate systems reduces the bias in the hydrogen concentration distribution in the radial direction inside the blast furnace compared to supplying hydrogen gas through a single system.

[0045] 3. Hydrogen concentration distribution in the raceway Simulations were used to examine the hydrogen concentration distribution in the raceway. The results showed that when hydrogen was supplied into the hot air flow path from a hydrogen injection port penetrating the upper wall of the tuyere body, as in (1) above, the hydrogen concentration in the upper space of the raceway increased. When hydrogen was supplied into the hot air flow path from a hydrogen injection port penetrating the lower wall of the tuyere body, as in (2) above, the hydrogen concentration in the lower space of the raceway increased. On the other hand, as in (4) above, when both hydrogen injection ports were used in combination, the mixing of hydrogen in the raceway was improved. In other words, it is thought that using both hydrogen injection ports in combination promotes the mixing of air blown from the raceway and hydrogen gas, resulting in a more uniform hydrogen concentration inside the blast furnace.

[0046] Based on the above results, it can be said that a blast furnace having the following configurations (i) to (iv) can suppress the bias in the concentration distribution of reducing gas in the radial direction inside the blast furnace when reducing gas is supplied to the inside of the blast furnace. (i) The blast furnace tuyeres have a tuyere body, a first reducing gas injection port, and a second reducing gas injection port. (ii) The tuyere body has a hot air passage. (iii) The first reducing gas injection port penetrates the wall of the tuyere body. (iv) The second reducing gas injection port penetrates the wall of the tuyere body at a different location from the first reducing gas injection port. [Explanation of Symbols]

[0047] 100 blast furnace 10 Hot air nozzles 11 Tuyere body 11a Hot air flow path 11ax aperture 12. First reducing gas injection port 12a Flow channel 12ax outlet 13. Second reducing gas injection port 13a Flow channel 13ax outlet 20. Sources of reducing gases 21. Reducing gas supply channel

Claims

1. A blast furnace having hot air tuyeres, The aforementioned hot air nozzle The tuyere body and The first reducing gas injection port, The second reducing gas injection port, It has, The tuyeres body has a hot air passage, The first reducing gas injection port penetrates the wall of the tuyere body, The second reducing gas injection port penetrates the wall of the tuyere body at a different position from the first reducing gas injection port, The outlet of the first reducing gas injection port and the outlet of the second reducing gas injection port each face the hot air flow path, The height position P1 of the center of the outlet of the first reducing gas injection port is above the height position P2 of the center of the opening of the tuyere body. The distance from the center of the downstream opening of the hot air passage to the center of the outlet of the first reducing gas injection port is 50 mm or more and 300 mm or less. The height position P3 of the center of the outlet of the second reducing gas injection port is lower than the height position P2 of the center of the opening of the tuyere body. The distance from the center of the downstream opening of the hot air passage to the center of the outlet of the second reducing gas injection port is 50 mm or more and 300 mm or less. The reducing gas supplied from the first reducing gas injection port and the second reducing gas injection port contains hydrogen gas. Blast furnace.

2. A method for supplying reducing gas to a blast furnace, Hot air is supplied into the interior of the blast furnace through the hot air tuyeres of the blast furnace, Reducing gas is supplied into the blast furnace via a first reducing gas injection port that penetrates the wall of the tuyere body of the hot air tuyere, and a second reducing gas injection port that penetrates the wall of the tuyere body at a different location from the first reducing gas injection port. Includes, Reducing gas is supplied from the outlet of the first reducing gas injection port and the outlet of the second reducing gas injection port to the hot air passage of the tuyere body. The height position P of the center of the outlet of the first reducing gas injection port. １ However, the height position P of the center of the opening of the tuyere body ２ It is located above, The distance from the center of the downstream opening of the hot air passage to the center of the outlet of the first reducing gas injection port is 50 mm or more and 300 mm or less. The height position P of the center of the outlet of the second reducing gas injection port. ３ However, the height position P of the center of the opening of the tuyere body ２ Located below, The distance from the center of the downstream opening of the hot air passage to the center of the outlet of the second reducing gas injection port is 50 mm or more and 300 mm or less. The reducing gas includes hydrogen gas. A method for supplying reducing gas to a blast furnace.

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