Blast furnace, tuyere for blast furnace, and method for supplying reducing gas to blast furnace

Abstract

A new technology for suppressing bias in the radial distribution of reducing gas concentration inside a blast furnace when reducing gas is supplied into the interior of the blast furnace is disclosed. One embodiment of the technology disclosed herein is a blast furnace having a hot blast tuyere, the hot blast tuyere having a tuyere body, a reducing gas injection port, and a reducing gas injection lance, the tuyere body having a hot blast flow path, the reducing gas injection port penetrating a wall of the tuyere body, and the reducing gas injection lance having an outlet within the hot blast flow path.

Description

[Technical Field]

[0001] The present application discloses a blast furnace, a tuyere for a blast furnace, and a method for supplying reducing gas to a blast furnace. [Background technology]

[0002] Reducing CO2 emissions in the steelmaking process has been studied. For example, when producing pig iron in a blast furnace, a reducing gas such as hydrogen gas may be used in place of a portion of the reducing material, such as coke. As a method for supplying reducing gas to a blast furnace, Patent Documents 1 and 2 disclose a method in which a lance for injecting reducing gas is disposed within the hot blast flow path or wall surface of a hot blast tuyere, and reducing gas is injected through the lance. Although not intended to inject reducing gas, Patent Document 3 discloses a method in which a fuel injection lance is inserted within the wall surface of a hot blast tuyere, and pulverized coal as fuel is injected into the blast furnace through the fuel injection lance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4997734 [Patent Document 2] Patent No. 5070706 [Patent Document 3] Patent No. 5840202 Summary of the Invention [Problem to be solved by the invention]

[0004] When reducing gas is supplied into a blast furnace through hot blast tuyere, the concentration of the reducing gas is likely to become uneven in the radial direction inside the blast furnace. [Means for solving the problem]

[0005] The present application discloses the following aspects as means for solving the above problems. <Aspect 1> A blast furnace having hot blast tuyere, The hot air tuyere The tuyere body, a reducing gas injection port; a reducing gas injection lance; and The tuyere body has a hot air flow path, the reducing gas injection port penetrates the wall of the tuyere body; The reducing gas injection lance has an outlet in the hot air flow path. Blast furnace. <Aspect 2> 2. The blast furnace of aspect 1, The outlet of the reducing gas blowing port faces the hot air flow path. Blast furnace. <Aspect 3> The blast furnace of aspect 1 or 2, A height position P1 of the center of the outlet of the reducing gas injection port is higher than a 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 reducing gas injection lance is lower than the height position P2 of the center of the opening of the tuyere body. Blast furnace. <Aspect 4> The blast furnace according to any one of aspects 1 to 3, The reducing gas supplied from the reducing gas injection port and the reducing gas injection lance contains hydrogen gas. Blast furnace. <Aspect 5> A method for supplying reducing gas to a blast furnace, comprising: Hot air is supplied into the inside of the blast furnace through a hot air tuyere of the blast furnace, supplying a reducing gas into the blast furnace through a reducing gas injection port penetrating a wall of the tuyere body of the hot blast tuyere and a reducing gas injection lance having an outlet in the hot blast flow path of the hot blast tuyere; A method for supplying reducing gas to a blast furnace, comprising: <Aspect 6> A method for supplying a reducing gas to a blast furnace according to aspect 5, A reducing gas is supplied from the outlet of the reducing gas blowing port to the hot air flow path. A method for supplying reducing gas to a blast furnace. <Aspect 7> The method for supplying a reducing gas to a blast furnace according to aspect 5 or 6, A height position P1 of the center of the outlet of the reducing gas blowing port is higher than a height position P2 of the center of the hot air tuyere, The height position P3 of the center of the outlet of the reducing gas injection lance is lower than the height position P2 of the center of the hot air tuyere. A method for supplying reducing gas to a blast furnace. <Aspect 8> The method for supplying a reducing gas to a blast furnace according to any one of aspects 5 to 7, The reducing gas comprises hydrogen gas. A method for supplying reducing gas to a blast furnace. <Aspect 9> A tuyere for a blast furnace, The tuyere body, a reducing gas injection port; a reducing gas injection lance; and The tuyere body has a hot air flow path, the reducing gas injection port penetrates the wall of the tuyere body; The reducing gas injection lance has an outlet in the hot air flow path. Tuyere for blast furnace. [Effects of the Invention]

[0006] According to the technology of the present disclosure, when reducing gas is supplied into the interior of a blast furnace, it is possible to suppress unevenness in the concentration of reducing gas in the radial direction of the interior of the blast furnace. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a blast furnace, with some components provided in the blast furnace omitted. [Figure 2A] 1 is a schematic diagram illustrating an example of the configuration of a tuyere body, a reducing gas injection port, and a reducing gas injection lance in a hot blast tuyere, with the upper side of the drawing corresponding to the furnace top side and the lower side of the drawing corresponding to the furnace bottom side. [Figure 2B] 1 is a schematic diagram illustrating an example of the configuration of a tuyere body, a reducing gas injection port, and a reducing gas injection lance in a hot blast tuyere, with the upper side of the drawing corresponding to the furnace top side and the lower side of the drawing corresponding to the furnace bottom side. [Figure 3A] 1 is a schematic diagram showing an example of the positional relationship between the opening of the tuyere body in the hot blast tuyere and the outlet of the reducing gas injection port. [Figure 3B] 1 is a schematic diagram showing an example of the positional relationship between the opening of the tuyere body in the hot blast tuyere and the outlet of the reducing gas injection port. [Figure 3C] 1 is a schematic diagram showing an example of the positional relationship between the opening of the tuyere body in the hot blast tuyere and the outlet of the reducing gas injection port. [Figure 3D] 1 is a schematic diagram showing an example of the positional relationship between the opening of the tuyere body in the hot blast tuyere and the outlet of the reducing gas injection port. [Figure 3E] 1 is a schematic diagram showing an example of the positional relationship between the opening of the tuyere body in the hot blast tuyere and the outlet of the reducing gas injection port. [Figure 4A] 1 is a schematic diagram showing an example of the positional relationship between the opening of a tuyere body in a hot blast tuyere and the outlet of a reducing gas injection lance. [Figure 4B] 1 is a schematic diagram showing an example of the positional relationship between the opening of a tuyere body in a hot blast tuyere and the outlet of a reducing gas injection lance. [Figure 4C] 1 is a schematic diagram showing an example of the positional relationship between the opening of a tuyere body in a hot blast tuyere and the outlet of a reducing gas injection lance. [Figure 4D] 1 is a schematic diagram showing an example of the positional relationship between the opening of a tuyere body in a hot blast tuyere and the outlet of a reducing gas injection lance. [Figure 4E] 1 is a schematic diagram showing an example of the positional relationship between the opening of a tuyere body in a hot blast tuyere and the outlet of a reducing gas injection lance. [Figure 5A] Simulation conditions are shown. [Figure 5B] Simulation conditions are shown. [Figure 5C] Simulation conditions are shown. [Figure 6A]The hydrogen concentration distribution based on the simulation results is shown. [Figure 6B] The hydrogen concentration distribution based on the simulation results is shown. [Figure 6C] The hydrogen concentration distribution based on the simulation results is shown. [Figure 7A] Simulation conditions are shown. [Figure 7B] Simulation conditions are shown. [Figure 7C] Simulation conditions are shown. [Figure 7D] Simulation conditions are shown. [Figure 8A] The hydrogen concentration distribution based on the simulation results is shown. [Figure 8B] The hydrogen concentration distribution based on the simulation results is shown. [Figure 8C] The hydrogen concentration distribution based on the simulation results is shown. [Figure 8D] The hydrogen concentration distribution based on the simulation results is shown. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, one embodiment of the blast furnace and the method for supplying a reducing gas to the blast furnace according to the present disclosure will be described. However, the blast furnace and the method for supplying a reducing gas to the blast furnace according to the present disclosure are not limited to the following embodiment.

[0009] 1.Blast furnace As shown in Fig. 1, a blast furnace 100 according to one embodiment has a hot blast tuyere 10. As shown in Figs. 2A and 2B, the hot blast tuyere 10 has a tuyere body 11, a reducing gas injection port 12, and a reducing gas injection lance 13. The tuyere body 11 has a hot blast flow path 11a. The reducing gas injection port 12 penetrates the wall of the tuyere body 11. The reducing gas injection lance 13 has an injection port 13ax in the hot blast flow path 11a.

[0010] In this application, the term "reducing gas injection port" refers to a reducing gas passage provided so as to penetrate the wall of the tuyere body, and the term "reducing gas injection lance" refers to a lance having an outlet in the hot air passage of the tuyere body without penetrating the wall of the tuyere body. The reducing gas injection lance may, for example, penetrate a blowpipe provided outside the furnace relative to the tuyere body.

[0011] 1.1 Hot air tuyere As shown in FIG. 1 , the hot blast tuyere 10 is provided, for example, below the shaft lower end 101ax of the blast furnace 100 and above the tap hole 102. The "shaft lower end" refers to the boundary between the shaft 101a and the belly 101b. The "shaft" refers to the portion above the belly 101b, where the furnace diameter typically increases from top to bottom. The "belly" refers to the portion below the shaft and above the bosch 101c, where the furnace diameter typically becomes maximum. The furnace diameter (diameter) of the belly 101b may be, for example, 5 m or more and 20 m or less, or 10 m or more and 18 m or less. The "tap hole" refers to a molten iron tap port provided at the bottom of the blast furnace 100. The "hot blast tuyere" refers to a nozzle for supplying hot air to the blast furnace. The blast furnace 100 may have a hot blast tuyere 10 below the belly lower end 101bx and above the tap hole 102, or may have a hot blast tuyere 10 below the morning glory lower end 101cx and above the tap hole 102.

[0012] The number of hot air tuyere 10 provided in the blast furnace 100 is not particularly limited and can be determined according to the internal volume of the blast furnace. In the blast furnace 100, a plurality of hot air tuyere 10 may be arranged in the circumferential direction of the blast furnace 100. In other words, in the blast furnace 100, a plurality of hot air tuyere 10 may be arranged in the circumferential direction when viewed from above. Usually, the height position P2 of the center of each of the plurality of hot air tuyere 10 is the same.

[0013] 1.1.1 Tuyere body The tuyere body 11 is a hollow member having a hot air flow path 11a. The upstream side of the hot air flow path 11a of the tuyere body 11 is connected to a blowpipe (not shown), and the downstream side of the hot air flow path 11a faces the interior of the blast furnace 100. The tuyere body 11 has an opening 11ax (hot air outlet) as an outlet of the hot air flow path 11a at the tip facing the interior of the blast furnace 100. The tuyere body 11 can be connected to a hot air stove outside the blast furnace 100 via a hot air pipe, a blowpipe, or the like. In other words, the blast furnace 100 can be configured so that hot air is supplied from the hot air stove to the interior of the blast furnace 100 via the hot air pipe, the blowpipe, and the tuyere body 11. The opening diameter of the tuyere body (the circle-equivalent diameter of the opening 11ax facing the interior of the blast furnace 100, i.e., 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.

[0014] 2A and 2B, the wall of the tuyere body 11 has, for example, an inner surface 11x facing the hot air flow path 11a, and an outer surface 11y and an end surface 11z facing the inside of the blast furnace 100. A reducing gas injection port 12, which will be described later, is provided so as to penetrate the wall. The tuyere body 11 may have a cooling water flow path inside the wall. This allows the tuyere body 11 and its surroundings to be cooled during operation of the blast furnace 100, thereby preventing thermal damage and the like. The tuyere body 11 is made of a known material, for example, copper.

[0015] 1.1.2 Reducing gas injection port The reducing gas injection port 12 can be connected to a reducing gas supply source 20 outside the blast furnace 100 via a reducing gas supply passage 21 or the like. In other words, the blast furnace 100 can 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 passage 21 and the reducing gas injection port 12. There are no particular limitations on the configurations of the reducing gas supply source 20 and the reducing gas supply passage 21.

[0016] 2A and 2B, the reducing gas injection port 12 is provided so as to penetrate the wall of the tuyere body 11. For example, the reducing gas injection port 12 has a flow path 12a in the wall surface of the tuyere body 11 and has an outlet 12ax on the downstream side of the flow path 12a. The length, longitudinal shape, opening shape, etc. of the flow path 12a of the reducing gas injection port 12 can be determined appropriately in consideration of the thickness of the wall of the tuyere body 11 and the water-cooling structure within the wall.

[0017] As shown in FIG. 2A, the outlet 12ax of the reducing gas injection port 12 may face the hot air flow passage 11a. That is, the reducing gas injection port 12 may supply the reducing gas so that it joins the hot air flow passage 11a. Alternatively, as shown in FIG. 2B, the outlet 12ax of the reducing gas injection port 12 may be provided on the end surface 11z of the tuyere body 11. That is, the reducing gas injection port 12 may supply the reducing gas into the blast furnace 100 independently of the hot air flow passage 11a. According to the findings of the present inventors, particularly when the outlet 12ax of the reducing gas injection port 12 faces the hot air flow passage 11a (that is, when the reducing gas is supplied from the outlet 12ax of the reducing gas injection port 12 to the hot air flow passage 11a) as shown in FIG. 2A, the concentration distribution of the reducing gas in the radial direction of the blast furnace 100 can be made more uniform. In this case, there is no particular limitation on 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 reducing gas blowing port 12. The distance may be, for example, 50 mm or more and 300 mm or less, or 75 mm or more and 150 mm or less.

[0018] The diameter (diameter of a circle with an area equivalent) of the outlet 12ax of the reducing gas injection port 12 may be, for example, 10 mm to 50 mm, or 20 mm to 30 mm. Alternatively, the diameter of the outlet 12ax of the reducing gas injection port 12 may be 10% to 50%, or 15% to 30% of the diameter of the opening 11ax of the tuyere body 11. When the outlet 12ax has such a diameter, it is easier to control the flow rate of the reducing gas.

[0019] The number of reducing gas injection ports 12 in the hot air tuyere 10 is not particularly limited. The number of reducing gas injection ports 12 provided in the hot air tuyere 10 may be one or more. The height position of the reducing gas injection port 12 provided in the hot air tuyere 10 is not particularly limited. The height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 will be described later.

[0020] 1.1.3 Reducing gas injection lance The reducing gas injection lance 13, like the reducing gas injection port 12, can be connected to a reducing gas supply source 20 outside the blast furnace 100 via a reducing gas supply passage 21 or the like. In other words, the blast furnace 100 can 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 passage 21 and the reducing gas injection lance 13. There are no particular limitations on the configuration of the reducing gas supply source 20 or the reducing gas supply passage 21. The reducing gas supply source 20 and the reducing gas passage 21 connected to the reducing gas injection lance 13 may be the same configuration as the reducing gas supply source 20 and the reducing gas passage 21 connected to the above-mentioned reducing gas injection port 12, or may be a different configuration.

[0021] The reducing gas supply source connected to the reducing gas injection port 12 and the reducing gas injection lance 13 may be the same or different. That is, reducing gas may be supplied from one reducing gas supply source to both the reducing gas injection port 12 and the reducing gas injection lance 13 via branch passages, or reducing gas may be supplied from one reducing gas supply source to the reducing gas injection port 12 and from another reducing gas supply source to the reducing gas injection lance 13.

[0022] 2A and 2B, the reducing gas injection lance 13 has a flow passage 13a therein and an outlet 13ax on the downstream side of the flow passage 13a, and the outlet 13ax may be disposed within the hot air flow passage 11a. The length, longitudinal shape, opening shape, etc. of the reducing gas injection lance 13 can be determined appropriately in consideration of the shape of the hot air flow passage 11a.

[0023] The outlet 13ax of the reducing gas injection lance 13 may be located within the hot air flow path 11a, and there is no particular limitation on 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 reducing gas injection lance 13. The distance may be, for example, 50 mm or more and 300 mm or less, or 75 mm or more and 150 mm or less.

[0024] The diameter (diameter of a circle with an area equivalent) of the outlet 13ax of the reducing gas injection lance 13 may be, for example, 10 mm to 50 mm, or 20 mm to 30 mm. Alternatively, the diameter of the outlet 13ax of the reducing gas injection lance 13 may be 10% to 50%, or 15% to 30% of the diameter of the opening 11ax of the tuyere body 11. When the outlet 13ax has such a diameter, it is easier to control the flow rate of the reducing gas.

[0025] The number of reducing gas injection lances 13 in the hot blast tuyere 10 is not particularly limited. The number of reducing gas injection lances 13 provided in the hot blast tuyere 10 may be one or more. The height position of the reducing gas injection lance 13 provided in the hot blast tuyere 10 is not particularly limited. For example, the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 will be described later.

[0026] 1.2 Height position of the tuyere body opening and each outlet As shown in FIG. 3A , a height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be higher than a 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 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 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 reducing gas injection port 12 may be located diagonally 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 reducing gas injection port 12 in the circumferential direction of the blast furnace 100 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Fig. 3B, when the opening 11ax of the tuyere body 11 is viewed from the front, a line L1 passing through the center of the opening 11ax and the center of the outlet 12ax may be inclined at an angle θ1 with respect to a vertical line L2 passing through the center of the opening 11ax. The angle θ1 may be, for example, between 0° and 45°. Note that while Fig. 3B illustrates an example in which the outlet 12ax is located on the left half side of the tuyere body 11, the outlet 12ax may also be located on the right half side of the tuyere body 11.

[0027] As shown in FIG. 3C , a height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be lower than a 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 reducing gas injection port 12 may be provided 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 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 reducing gas injection port 12 may be provided obliquely 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 reducing gas injection port 12 in the circumferential direction of the blast furnace 100 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Fig. 3D, when the opening 11ax of the tuyere body 11 is viewed from the front, a line L1 passing through the center of the opening 11ax and the center of the outlet 12ax may be inclined at an angle θ2 with respect to a vertical line L2 passing through the center of the opening 11ax. The angle θ2 may be, for example, between 0° and 45°. Note that while Fig. 3D illustrates an example in which the outlet 12ax is located on the left half side of the tuyere body 11, the outlet 12ax may also be located on the right half side of the tuyere body 11.

[0028] As shown in Fig. 3E, a height position P1 of the center of the outlet 12ax of the reducing gas blowing port 12 may be the same as a 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 reducing gas blowing port 12 may be provided directly beside the center of the opening 11ax of the tuyere body 11. Note that, although Fig. 3E illustrates an example in which the outlet 12ax is located on the left half side of the tuyere body 11, the outlet 12ax may also be located on the right half side of the tuyere body 11.

[0029] 4A , a height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 may be higher than a 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 reducing gas injection lance 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 reducing gas injection lance 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 reducing gas injection lance 13 may be located diagonally 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 reducing gas injection lance 13 in the circumferential direction of the blast furnace 100 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Fig. 4B, when the opening 11ax of the tuyere body 11 is viewed from the front, a line L3 passing through the center of the opening 11ax and the center of the outlet 13ax may be inclined at an angle θ3 with respect to a vertical line L2 passing through the center of the opening 11ax. The angle θ3 may be, for example, between 0° and 45°. Note that while Fig. 4B illustrates an example in which the outlet 13ax is located on the right half of the tuyere body 11, the outlet 13ax may also be located on the left half of the tuyere body 11.

[0030] As shown in FIG. 4C , a height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 may be lower than a 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 reducing gas injection lance 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 reducing gas injection lance 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 reducing gas injection lance 13 may be located obliquely 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 reducing gas injection lance 13 in the circumferential direction of the blast furnace 100 may be different from the position of the center of the opening 11ax of the tuyere body 11. For example, as shown in Fig. 4D, when the opening 11ax of the tuyere body 11 is viewed from the front, a line L1 passing through the center of the opening 11ax and the center of the outlet 13ax may be inclined at an angle θ4 with respect to a vertical line L2 passing through the center of the opening 11ax. The angle θ4 may be, for example, between 0° and 45°. Note that while Fig. 4D illustrates an example in which the outlet 13ax is located on the right half of the tuyere body 11, the outlet 13ax may also be located on the left half of the tuyere body 11.

[0031] 4E, a height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 may be the same as a 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 reducing gas injection lance 13 may be provided so as to coincide with the center of the opening 11ax of the tuyere body 11, or may be provided directly beside the center of the opening 11ax.

[0032] According to the findings of the present inventors, when the height positions of the outlets 12ax, 13ax are divided into upper and lower, the distribution of the reducing gas concentration in the radial direction of 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 reducing gas injection port 12 may be higher than the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13. For example, in one embodiment, the height position P1 of the center of the outlet 12ax of the 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 reducing gas injection lance 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 reducing gas injection port 12 may be located at any position in the upper half, and the outlet 13ax of the reducing gas injection lance 13 may be located at any position in the lower half. Alternatively, in one embodiment, the height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be lower than the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13. For example, the height position P1 of the center of the outlet 12ax of the 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, and the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 may be higher 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 reducing gas injection port 12 may be located at any position in the lower half, and the outlet 13ax of the reducing gas injection lance 13 may be located at any position in the upper half. Alternatively, in one embodiment, when the tuyere body 11 is divided into an upper half and a lower half, the outlet 12ax of the reducing gas injection port 12 and the outlet 13ax of the reducing gas injection lance 13 may both be located at any position in the upper half, and the height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be located at a height position different from the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13.Alternatively, in one embodiment, when the tuyere body 11 is divided into an upper half and a lower half, the outlet 12ax of the reducing gas injection port 12 and the outlet 13ax of the reducing gas injection lance 13 may both be located somewhere in the lower half, and the height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be at a height position different from the height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13.

[0033] 1.4 Hot air The hot air supplied from the hot air tuyere 10 into the inside of the blast furnace 100 may be, 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 1000°C or higher and 2000°C or lower, 1000°C or higher and 1700°C or lower, 1000°C or higher and 1500°C or lower, or 1000°C or higher and 1300°C or lower. The flow velocity of the hot air at the opening 11ax of the tuyere body 11 may be adjusted appropriately depending on the operating status of the blast furnace 100, and may be, for example, 100 m / s or higher and 300 m / s or lower, or 200 m / s or higher and 250 m / s or lower.

[0034] 1.5 Reducing gas The reducing gas is a gas that functions as a reducing agent inside the blast furnace 100. In other words, even if a gas does not function as a reducing agent before being supplied to the blast furnace 100, the term "reducing gas" as used herein includes any gas that can generate a reducing agent (reducing component) by thermal decomposition or the like inside the blast furnace 100. Examples of such reducing gases include at least one selected from hydrogen gas, hydrocarbon gas (e.g., methane gas), carbon monoxide gas, ammonia gas, and alcohol gas (e.g., methanol gas or ethanol gas). In addition, in the technology disclosed herein, 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. One of these reducing gases may be used alone, or two or more may be used in combination. In particular, when the reducing gas contains hydrogen gas, the technology disclosed herein is expected to be even more effective. The temperature of the reducing gas supplied from the reducing gas injection port 12 and the reducing gas injection lance 13 into the blast furnace 100 may be, for example, 0°C or higher and 2000°C or lower, or 25°C or higher and 1500°C or lower. In the present embodiment, the flow velocity of the reducing gas at the outlet 12ax of the reducing gas injection port 12 and the outlet 13ax of the reducing gas injection lance 13 may be, for example, lower than the sonic velocity at the operating temperature of each reducing gas. For example, the flow velocity of the reducing gas at each of the outlet 12ax of the reducing gas injection port 12 and the outlet 13ax of the reducing gas injection lance 13 may be 100 m / s or higher and 1000 m / s or lower. In particular, if the flow velocity is 200 m / s or higher and 800 m / s or lower, ventilation inside the blast furnace 100 is stabilized, and operation in which the reduction reaction in the furnace proceeds stably is likely to be achieved.

[0035] 1.6 Other gases Other gases may be supplied together with the reducing gas from the reducing gas injection port 12 and the reducing gas injection lance 13. Examples of other gases include inert gases such as nitrogen gas.

[0036] 2. Method of supplying reducing gas to the blast furnace The technology of the present disclosure 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 includes the following steps: Hot air is supplied into the inside of the blast furnace 100 through the hot air tuyere 10 of the blast furnace 100, Supplying a reducing gas into the blast furnace 100 through a reducing gas injection port 12 penetrating the wall of the tuyere body 11 of the hot blast tuyere 10 and a reducing gas injection lance 13 having an outlet 13ax in the hot blast flow path 11a of the hot blast tuyere 10; Includes.

[0037] Details and preferred embodiments 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, reducing gas may be supplied to the hot air flow path 11a from the outlet 12ax of the reducing gas injection port 12. Furthermore, a height position P1 of the center of the outlet 12ax of the reducing gas injection port 12 may be higher than a height position P2 of the center of the opening 11ax of the tuyere body 11, and a height position P3 of the center of the outlet 13ax of the reducing gas injection lance 13 may be lower than a height position P2 of the center of the opening 11ax of the tuyere body 11. Furthermore, the reducing gas may contain hydrogen gas.

[0038] 3.Tuyere for blast furnace The technology of the present disclosure also has an aspect as a blast furnace tuyere. The blast furnace tuyere corresponds to the hot blast tuyere 10 described above. That is, the blast furnace tuyere 10 according to one embodiment has a tuyere body 11, a reducing gas injection port 12, and a reducing gas injection lance 13. Here, the tuyere body 11 has a hot blast flow path 11a, the reducing gas injection port 12 penetrates the wall of the tuyere body 11, and the reducing gas injection lance 13 has an outlet 13ax within the hot blast flow path 11a. Each configuration is as described above, and detailed description thereof will be omitted here.

[0039] 3. Supplementary Information In the operation of the blast furnace 100, for example, iron ore (iron oxide), coke, etc. are charged into the interior of the blast furnace 100 from the top of the blast furnace 100, hot air is supplied into the interior of the blast furnace 100 from a hot stove outside the blast furnace 100 via a hot air pipe and hot air tuyere 10, reducing gas is supplied into the interior of the blast furnace 100 from a reducing gas supply source outside the blast furnace 100 via a reducing gas flow path and a reducing gas injection port 12, and reducing gas is supplied into the interior of the blast furnace 100 from a reducing gas supply source outside the blast furnace 100 via a reducing gas flow path and a reducing gas injection lance 13. The coke, etc. supplied into the interior of the blast furnace 100 is combusted to generate reducing gas. The reducing gas generated by the combustion of the coke, etc. and the reducing gas supplied from the reducing gas injection port 12 and the reducing gas injection lance 13 reduce and dissolve the iron oxide to obtain molten iron. The molten pig iron is tapped from a tap hole 102 provided at the bottom of the blast furnace 100. In this embodiment, reducing gas is supplied into the blast furnace 100 through the reducing gas injection port 12 and the reducing gas injection lance 13, thereby reducing the amount of carbon-containing reducing material, such as coke, used. As a result, the amount of CO2 generated can be reduced. The blast furnace 100 can have various configurations as long as it is capable of producing pig iron as described above. For example, the blast furnace 100 may have other tuyere(s), ports, or lance(s) in addition to the hot blast tuyere 10. Furthermore, the hot blast tuyere 10 may have other ports, lances, or the like in addition to the tuyere body 11, the reducing gas injection port 12, and the reducing gas injection lance 13. For example, the hot blast tuyere 10 may have a pulverized coal injection lance or the like. The configuration of the blast furnace 100 other than the hot blast tuyere 10 is well known in the art, and therefore will not be described in detail here.

[0040] 4.Effects As described above, according to this embodiment, the reducing gas injection port 12 and the reducing gas injection lance 13 are used in combination as a means for supplying reducing gas into the interior of the blast furnace 100, and reducing gas is supplied from a plurality of outlets 12ax, 13ax, thereby making it possible to make the concentration distribution of reducing gas in the radial direction of the interior of the blast furnace 100 more uniform than when reducing gas is supplied from only one outlet.

[0041] Furthermore, when the reducing gas injection port 12 and the reducing gas injection lance 13 are used in combination as a means for supplying reducing gas into the blast furnace 100, a larger amount of reducing gas can be supplied into the blast furnace 100, and the supply of reducing gas can be more easily stabilized, compared to when reducing gas is supplied in a single system. According to the inventor's findings, if the number of reducing gas injection ports provided in the hot blast tuyere is too large in order to supply a larger amount of reducing gas into the blast furnace, water cooling of the hot blast tuyere tends to be hindered, and if the number of reducing gas injection lances is too large, the amount of combustion of the reducing gas in the hot blast tuyere tends to increase, increasing the thermal load of the equipment. In contrast, by using the reducing gas injection port and the reducing gas injection lance in combination in the hot blast tuyere, a large amount of reducing gas can be supplied into the blast furnace even with a minimum number of reducing gas injection ports and reducing gas injection lances, and the above-mentioned problems are less likely to become apparent. Furthermore, by using the reducing gas injection port 12 and the reducing gas injection lance 13 in combination, it is possible to achieve both the advantageous effects of the port structure (for example, the tendency for the amount of reducing gas combustion in the hot air tuyere to be low) and the advantageous effects of the lance structure (for example, the ease of replacing the lance during operation). [Example]

[0042] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. The present invention allows for various conditions to be adopted as long as the gist of the invention is not deviated from and the object is achieved. In the following examples, hydrogen gas is used as the reducing gas, but the type of reducing gas is not limited to this. In the examples shown below, the concentration of hydrogen molecules inside a blast furnace was evaluated by performing a simulation taking into account gas flow, heat transfer, and chemical reactions using the general-purpose thermal fluid analysis software FLUENT. The raceway region near the tuyere was treated as a cavity where no coke was present, and the coke-packed bed region in the blast furnace away from the raceway was treated as a porous medium. The standard k-ε model was used for turbulence analysis, the vortex dissipation model for gas combustion, and the Field's model for the gasification reactions of coke to O2, CO2, and HO.

[0043] 1. When hydrogen gas is supplied through one system Using simulation, (1) When hydrogen is supplied into the hot air channel only through the hydrogen injection port that penetrates the lower wall of the tuyere body (Fig. 5A). (2) When hydrogen is supplied into the hot air channel only through the hydrogen injection port that penetrates the upper wall of the tuyere body (Fig. 5B). (3) When hydrogen is supplied only from a hydrogen injection lance with an outlet inside the hot air passage of the tuyere body (Fig. 5C). For each of the above, 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 in the blast furnace. The flow rate of hydrogen gas supplied from the port / lance was 2615 Nm 3 / 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 12 m from the center of the tuyere.

[0044] As shown in Figures 6A to 6C, it can be seen that the bias in the hydrogen concentration inside the furnace varies depending on the means and position of hydrogen gas supply. For example, in the case of (1) above, the hydrogen concentration is high between the furnace wall and the furnace center inside the blast furnace. In addition, in the case of (2) above, the hydrogen concentration is high on the wall side and in the furnace center inside the blast furnace. In addition, in the case of (3) above, the hydrogen concentration is high in the area close to the furnace wall between the furnace wall and the furnace center inside the blast furnace. In other words, it is thought that by using multiple types of hydrogen gas injection means and / or multiple injection positions in the hot blast tuyere, the hydrogen concentration distribution in the radial direction inside the blast furnace can be averaged and uniformed.

[0045] 2. When hydrogen gas is supplied through two systems Using simulation, (4) When hydrogen is supplied into the hot air channel from each of the two hydrogen injection ports that penetrate the upper wall of the tuyere body (Fig. 7A). (5) When hydrogen was supplied from each of the two hydrogen injection lances located inside the hot air passage of the tuyere body (Fig. 7B). (6) Hydrogen was supplied into the hot air channel from one hydrogen injection port penetrating the upper wall of the tuyere body, and hydrogen was supplied from one hydrogen injection lance located inside the hot air channel of the tuyere body (Figure 7C). (7) For reference, in the case of (2) above (Figure 7D) For each of the above cases (4) to (6), 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. The flow rate of the supplied hydrogen gas was 4270 Nm3 for the two systems in total. 3 / hr, and in the case of (7) above, 4270 Nm 3 / hr. Figure 8A shows the hydrogen concentration distribution in the case of (4) above, Figure 8B shows the hydrogen concentration distribution in the case of (5) above, Figure 8C shows the hydrogen concentration distribution in the case of (6) above, and Figure 8D shows the hydrogen concentration distribution in the case of (7) above.

[0046] 8A to 8D, it can be seen that supplying hydrogen gas through two 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. In particular, as shown in Fig. 8C, it can be seen that the bias in the hydrogen concentration distribution in the radial direction inside the blast furnace is minimized when both the hydrogen injection port and the hydrogen injection lance are used in combination.

[0047] 3. Hydrogen concentration distribution in the raceway When the hydrogen concentration distribution in the raceway was confirmed using simulations, it was found that when hydrogen was supplied into the hot blast channel from each of the two hydrogen injection ports penetrating the upper wall of the tuyere body as described above (4), the hydrogen concentration in the upper space of the raceway was high, and when hydrogen was supplied from each of the two hydrogen injection lances located inside the hot blast channel of the tuyere body as described above (5), the hydrogen concentration in the lower part of the raceway was high, but when the hydrogen injection port and hydrogen injection lance were used together as described above (6), the hydrogen mixing in the raceway was improved. In other words, when the hydrogen injection port and hydrogen injection lance were used together, it was possible to promote the mixing of the air blown from the raceway with the hydrogen gas, and it was thought that the hydrogen concentration inside the blast furnace would be uniform.

[0048] From the above results, it can be said that, according to a blast furnace having the following configurations (i) to (iv), when reducing gas is supplied into the inside of the blast furnace, it is possible to suppress bias in the concentration distribution of the reducing gas in the furnace radial direction inside the blast furnace. (i) A hot blast tuyere of a blast furnace has a tuyere body, a reducing gas injection port, and a reducing gas injection lance. (ii) The tuyere body has a hot air flow path. (iii) the reducing gas injection port penetrates the wall of the tuyere body; (iv) The reducing gas injection lance has an outlet in the hot air flow path. [Explanation of symbols]

[0049] 100 blast furnace 10 Hot air tuyere 11 Tuyere body 11a Hot air flow path 11ax aperture 12 Reducing gas injection port 12a Flow path 12ax outlet 13 Reducing gas injection lance 13a Flow path 13ax outlet 20 Reducing gas supply source 21 reducing gas supply channel

Claims

1. A blast furnace having hot air tuyeres, The aforementioned hot air nozzle The tuyere body and The reducing gas injection port, Reducing gas injection lance, It has, The tuyeres body has a hot air passage, The aforementioned reducing gas injection port penetrates the wall of the tuyere body, The reducing gas injection lance has an outlet in the hot air passage, Blast furnace.

2. A blast furnace according to claim 1, The outlet of the reducing gas injection port faces the hot air passage, Blast furnace.

3. A blast furnace according to claim 1, Height position P of the center of the outlet of the aforementioned 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, Height position P of the center of the outlet of the aforementioned reducing gas blowing lance ３ However, the height position P of the center of the opening of the tuyere body ２ Located below, Blast furnace.

4. A blast furnace according to any one of claims 1 to 3, The reducing gas supplied from the reducing gas injection port and the reducing gas injection lance includes hydrogen gas. Blast furnace.

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 reducing gas injection port that penetrates the wall of the tuyere body of the hot air tuyere, and a reducing gas injection lance having an outlet within the hot air flow path of the hot air tuyere. A method for supplying reducing gas to a blast furnace, including the supply of reducing gas.

6. A method for supplying reducing gas to a blast furnace according to claim 5, The reducing gas is supplied from the outlet of the reducing gas injection port to the hot air flow path. A method for supplying reducing gas to a blast furnace.

7. A method for supplying reducing gas to a blast furnace according to claim 5, Height position P of the center of the outlet of the aforementioned 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, Height position P of the center of the outlet of the aforementioned reducing gas blowing lance ３ However, the height position P of the center of the opening of the tuyere body ２ Located below, A method for supplying reducing gas to a blast furnace.

8. A method for supplying reducing gas to a blast furnace according to any one of claims 5 to 7, The reducing gas includes hydrogen gas. A method for supplying reducing gas to a blast furnace.

9. A tuyeres for blast furnaces, The tuyere body and The reducing gas injection port, Reducing gas injection lance, It has, The tuyeres body has a hot air passage, The aforementioned reducing gas injection port penetrates the wall of the tuyere body, The reducing gas injection lance has an outlet in the hot air passage, Tuyere for blast furnace.

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