Blast furnaces and blast furnace tuyere
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2026-03-11
AI Technical Summary
In blast furnaces, providing a reducing gas passage through the tuyere wall increases the cross-sectional area of the cooling water passage, leading to a decrease in flow rate and cooling performance, which can result in tuyere melting damage.
The tuyere design incorporates a third flow path with ribs inside the wall to reduce the cross-sectional area, ensuring a higher flow rate of cooling water and maintaining cooling performance.
The ribbed structure in the tuyere's cooling water path enhances cooling efficiency, preventing melting damage and maintaining optimal operating conditions.
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Abstract
Description
[Technical Field]
[0001] The present application discloses a blast furnace and a tuyere for 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 Document 1 discloses 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 2 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. 5840202 Summary of the Invention [Problem to be solved by the invention]
[0004] In a blast furnace having a tuyere, when a reducing gas passage is provided so as to penetrate the wall of the tuyere, the wall of the tuyere needs to be thickened. On the other hand, when the wall of the tuyere is thickened, the cross-sectional area of the cooling water passage provided inside the wall of the tuyere increases. When the cross-sectional area of the cooling water passage increases, the flow rate of the cooling water in the cooling water passage decreases, and the cooling performance decreases. As a result, for example, the tuyere portion protruding into the furnace is not sufficiently cooled, and tuyere melting damage and the like are likely to occur. In this regard, a new technology is needed that can increase the flow rate of the cooling water in the cooling water passage provided inside the wall of the tuyere. [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 a tuyere, The tuyere has a tuyere body, a first flow path, a second flow path, and a third flow path; The tuyere body has a protruding portion protruding into the inside of the blast furnace, the first flow path is defined by an inner wall of the tuyere body; the second flow path is connected to a reducing gas source; the second flow passage penetrates the wall of the tuyere body; the third flow path is connected to a cooling water source; The third flow path is provided inside the wall of the tuyere body, the third flow path has one or more ribs that reduce a cross-sectional area of the third flow path at least at the protrusion. Blast furnace. <Aspect 2> 2. The blast furnace of aspect 1, The third flow path has a plurality of the ribs at least in the protruding portion. Blast furnace. <Aspect 3> The blast furnace of aspect 1 or 2, The rib protrudes from one of the opposing inner wall surfaces of the third flow path toward the other inner wall surface. Blast furnace. <Aspect 4> The blast furnace according to any one of aspects 1 to 3, The third flow path has a first inner wall surface on the tuyere tip side and a second inner wall surface opposite to the first inner wall surface, the third flow path has one or more first ribs at least in the protrusion; the first rib protrudes from the second inner wall surface toward the first inner wall surface, a gap exists between the tip of the first rib and the first inner wall surface; Blast furnace. <Aspect 5> The blast furnace according to any one of aspects 1 to 4, the third flow path has one or more second ribs at least in the protrusion; the second rib protrudes from the first inner wall surface toward the second inner wall surface, a gap exists between the tip of the second rib and the second inner wall surface; Blast furnace. <Aspect 6> The blast furnace according to any one of aspects 1 to 5, The third flow path is serpentine at least in the protruding portion. Blast furnace. <Aspect 7> The blast furnace according to any one of aspects 1 to 6, When the tuyere is divided into two parts, a first part and a second part, by a plane passing through the axis of the first flow path, When the second flow path is present in the first portion, the rib is also present in at least the first portion; When the second flow path is present in the second portion, the rib is also present in at least the second portion. Blast furnace. <Aspect 8> The blast furnace according to any one of aspects 1 to 6, When the tuyere is divided into two parts, an upper part and a lower part, by a plane passing through the axis of the first flow path, When the second flow path is present in the upper portion, the rib is also present in at least the upper portion; When the second flow path is present in the lower portion, the rib is also present in at least the lower portion. Blast furnace. <Aspect 9> The blast furnace according to any one of aspects 1 to 8, The third flow path has an outer flow path that cools the outer wall side of the tuyere body at least in the protruding portion, and an inner flow path that cools the inner wall side of the tuyere body. Blast furnace. <Aspect 10> 10. The blast furnace of aspect 9, The rib is provided in a part of the inner flow path. Blast furnace. <Aspect 11> 11. The blast furnace of aspect 9 or 10, the rib protrudes from one of the opposing inner wall surfaces of the inner flow path toward the other inner wall surface, a cross-sectional area of the inner flow passage, at a portion where the rib protrudes, is larger than a cross-sectional area of the outer flow passage when it is assumed that the rib does not exist; Blast furnace. <Aspect 12> A tuyere for a blast furnace, A tuyere body, a first flow path, a second flow path, and a third flow path, The tuyere body has a protruding portion that protrudes into the inside of the blast furnace when installed in the blast furnace, the first flow path is defined by an inner wall of the tuyere body; the second flow path is connected to a reducing gas source; the second flow passage penetrates the wall of the tuyere body; the third flow path is connected to a cooling water source; The third flow path is provided inside the wall of the tuyere body, the third flow path has one or more ribs that reduce a cross-sectional area of the third flow path at least at the protrusion. Tuyere for blast furnace. [Effects of the Invention]
[0006] In a blast furnace tuyere, when a second flow path (reducing gas flow path) is provided so as to penetrate the wall of the tuyere body, the cross-sectional area of the third flow path (cooling water flow path) inside the wall of the tuyere body increases, which reduces the flow rate of the cooling water in the third flow path and may result in the necessary cooling performance not being ensured. In contrast, according to the technology disclosed herein, by providing a predetermined rib in the third flow path, the flow rate of the cooling water in the third flow path is ensured and cooling performance is easily restored and maintained. [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 2] 1 is a schematic diagram illustrating an example of a cross-sectional configuration of a tuyere provided in a blast furnace. [Figure 3] 1 is a schematic diagram showing an example of the second flow path (reducing gas flow path) and third flow path (cooling water flow path) of a tuyere provided in a blast furnace. The diagram shows an expanded view of the internal structure of the tuyere, with the "0°" position in the diagram corresponding to directly above the central axis of the first flow path of the tuyere, and the "180°" position in the diagram corresponding to directly below the central axis of the first flow path of the tuyere. In other words, the ranges of 0° to 90° and 270° to 0° (360°) in the diagram correspond to the upper part of the tuyere, and the ranges of 90° to 180° and 180° to 270° correspond to the lower part of the tuyere. [Figure 4] 1 is a schematic diagram showing an example of the second flow path (reducing gas flow path) and the third flow path (cooling water flow path) of a tuyere provided in a blast furnace. This figure shows an expanded view of the internal structure of the tuyere, and the meanings of 0°, 90°, 180°, and 270° in this figure are the same as those in FIG. 3. [Figure 5] FIG. 4 is a schematic diagram for explaining an example of a flow path cross-sectional area. [Figure 6] FIG. 10 is a schematic diagram for explaining an example of the dimensions of a rib. [Figure 7] 10A and 10B are schematic diagrams illustrating an example of the shape of ribs in the third flow path. [Figure 8A] 10 is a diagram showing an example of the positional relationship between the second flow passage and the rib, and corresponds to a front view of the tip of the tuyere. [Figure 8B] 10 is a diagram showing an example of the positional relationship between the second flow passage and the rib, and corresponds to a front view of the tip of the tuyere. [Figure 9A] 10 is a diagram showing an example of the positional relationship between the second flow passage and the rib, and corresponds to a front view of the tip of the tuyere. [Figure 9B] 10 is a diagram showing an example of the positional relationship between the second flow passage and the rib, and corresponds to a front view of the tip of the tuyere. [Figure 10]The graph shows the relationship between the gap width at the tip of the rib and the cooling water flow velocity. DETAILED DESCRIPTION OF THE INVENTION
[0008] Hereinafter, an embodiment of the blast furnace and blast furnace tuyere according to the present disclosure will be described. However, the blast furnace and blast furnace tuyere according to the present disclosure are not limited to the following embodiment.
[0009] As shown in FIG. 1, a blast furnace 100 according to one embodiment has a tuyere 10. As shown in FIGS. 2 to 4, the tuyere 10 has a tuyere body 11, a first flow path 12, a second flow path 13, and a third flow path 14. The tuyere body 11 has a protrusion 11x that protrudes into the interior of the blast furnace 100. The first flow path 12 is defined by an inner wall 11ax of the tuyere body 11. The second flow path 13 is connected to a reducing gas source 20. The second flow path 13 penetrates a wall 11a of the tuyere body 11. The third flow path 14 is connected to a cooling water source 30. The third flow path 14 is provided inside the wall 11a of the tuyere body 11. The third flow path 14 has one or more ribs 15 that reduce the cross-sectional area of the third flow path 14 at least at the protrusion 11x.
[0010] 1. Tuyere As shown in FIG. 1 , the tuyere 10 may be located, 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 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 located at the bottom of the blast furnace 100. The "tuyere" refers to a nozzle for supplying reducing materials, etc. to the blast furnace. The blast furnace 100 may have the tuyere 10 below the belly lower end 101bx and above the tap hole 102, or may have the tuyere 10 below the bosh lower end 101cx and above the tap hole 102. Alternatively, the tuyere 10 may be provided in the shaft 101a of the blast furnace 100, for example.
[0011] The number of tuyere 10 provided in the blast furnace 100 is not particularly limited and can be determined depending on the internal volume of the blast furnace. In the blast furnace 100, a plurality of 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 tuyere 10 may be arranged in the circumferential direction when viewed from above. Usually, the height positions of the centers of the plurality of tuyere 10 are the same.
[0012] 1.1 Tuyere body and first passage The tuyere 10 has a hollow tuyere body 11. The tuyere body 11 has a wall 11a, and a first flow passage 12 is defined by an inner wall 11ax of the wall 11a. The upstream side of the first flow passage 12 (the side opposite to the tip 11az of the tuyere body 11) of the tuyere body 11 is connected to a blowpipe (not shown), and the downstream side of the first flow passage 12 (the side of the tip 11az of the tuyere body 11) faces the inside of the blast furnace 100. The tuyere body 11 has an opening 12x facing the interior of the blast furnace 100, and the opening 12x serves as an outlet of the first flow passage 12. The type of fluid passing through the first flow passage 12 is not particularly limited. When the tuyere 10 is provided below the shaft lower end 101ax of the blast furnace 100 and above the taphole 102, the first flow passage 12 may be a flow passage for hot air and a solid reducing material, for example. In this case, the tuyere body 11 may be connected to a hot stove outside the blast furnace 100 via a hot blast pipe, a blowpipe, or the like. In other words, the blast furnace 100 may be configured so that hot air is supplied from the hot stove to the inside of the blast furnace 100 via the hot blast pipe, the blowpipe, and the tuyere body 11. Alternatively, when the tuyere 10 is provided in the shaft 101a of the blast furnace 100, the first flow path 12 may be, for example, a flow path for reducing gas. The opening diameter of the outlet of the first flow path 12 (the circle equivalent diameter of the opening 12x 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. The length of the line segment connecting the center of the opening 12x as the outlet of the first flow path 12 and the center of the opening as the inlet of the first flow path 12 (the length of the first flow path 12 in the tuyere body 11) may be, for example, 400 mm or more and 600 mm or less, or 450 mm or more and 550 mm or less.
[0013] The tuyere body 11 has a protruding portion 11x that protrudes into the interior of the blast furnace 100. That is, at least a portion of the tuyere body 11 protrudes from the inner wall of the blast furnace 100 toward the center of the furnace. The protruding length of the tuyere body 11 is not particularly limited and may be the same as a conventional protruding length. The protruding portion 11x of the tuyere body 11 is a portion that is likely to become particularly hot during operation of the blast furnace 100 and is prone to melting damage, etc. The technology of the present disclosure prevents a decrease in the flow rate of the cooling water in the protruding portion 11x and reduces melting damage, etc. of the tuyere by devising a structure for the third flow path 14 (cooling water flow path) in the protruding portion 11x.
[0014] The wall 11a of the tuyere body 11 has, for example, an inner wall 11ax that defines the first flow passage 12, an outer wall 11ay opposite the inner wall 11ax, and a tip 11az that faces the inside of the blast furnace 100. The tuyere body 11 has a second flow passage 13 (reducing gas flow passage) and a third flow passage 14 (cooling water flow passage) described below inside the wall 11a. When the second flow passage 13 is provided inside the wall 11a of the tuyere body 11 together with the third flow passage 14, the wall 11a becomes thicker by the amount of the second flow passage 13. The thickness of the wall 11a of the tuyere body 11 (the thickness between the inner wall 11ax and the outer wall 11ay) is, for example, larger than the flow passage diameter of the second flow passage 13. The minimum thickness of the wall 11a of the tuyere body 11 at the portion where the second flow passage 13 is provided may be, for example, 40 mm or more and 90 mm or less, or 50 mm or more and 80 mm or less. The wall 11a of the tuyere body 11 is made of a known material, for example, copper.
[0015] 1.2 Second flow path (reducing gas flow path) As shown in Figures 3 and 4, the second flow passage 13 penetrates the wall 11a of the tuyere body 11. For example, the second flow passage 13 extends inside the wall 11a of the tuyere body 11 from the side opposite to the tip 11az of the tuyere body 11 (the base side connected to a blowpipe or the like) to the tip 11az side. An outlet 13x (reducing gas outlet) of the second flow passage 13 may be provided in the inner wall 11ax of the tuyere body 11. That is, the blast furnace 100 may be configured so that the reducing gas is supplied to the first flow passage 12 via the outlet 13x. Alternatively, as shown in Figures 3 and 4, the outlet 13x may be provided in the tip 11az of the tuyere body 11.
[0016] The length, longitudinal shape, opening shape, etc. of the second flow passage 13 can be determined appropriately taking into account the wall thickness of the tuyere body 11 and the third flow passage 14 inside the wall. The second flow passage 13 can be connected to a reducing gas source 20 outside the blast furnace 100 via piping, etc. In other words, the blast furnace 100 can be configured so that reducing gas is supplied from the reducing gas source 20 to the inside of the blast furnace 100 via piping and the second flow passage 13, for example. There are no particular limitations on the form of the reducing gas source 20 or the piping.
[0017] In the blast furnace 100, the tuyere 10 may have a plurality of second flow paths 13. In this case, the reducing gas source 20 connected to one second flow path 13 and the reducing gas sources 20 connected to the other second flow paths 13 may be the same as or different from each other. That is, reducing gas may be supplied from one reducing gas source 20 to the plurality of second flow paths 13 via branch flow paths, or reducing gas may be supplied from one reducing gas source 20 to one second flow path 13 and then supplied from another reducing gas source 20 to the other second flow paths 13.
[0018] The diameter of the second flow path 13 (the diameter of a circle equivalent to the area of the cross-sectional shape of the flow path) may be, for example, 10 mm to 50 mm, or 20 mm to 30 mm. Alternatively, the diameter of the second flow path 13 may be 5% to 30% or 10% to 20% of the diameter (diameter of a circle equivalent to the area) of the opening 12x serving as the outlet of the first flow path 12. The diameter (diameter of a circle equivalent to the area) of the outlet 13x of the second flow path 13 may be, for example, 10 mm to 50 mm, or 20 mm to 30 mm. Alternatively, the diameter of the outlet 13x of the second flow path 13 may be 5% to 30% or 10% to 20% of the diameter (diameter of a circle equivalent to the area) of the opening 12x serving as the outlet of the first flow path 12. When the second flow path 13 and its outlet 13x have such diameters, the flow rate of the reducing gas can be more easily controlled.
[0019] 3 and 4 illustrate an example in which outlet 13x of second flow path 13 is located diagonally above (at a position of approximately 45° when directly above is 0° and directly below is 180°) the center of opening 12x serving as an outlet of first flow path 12, but the height position of outlet 13x of second flow path 13 is not limited to this. The height position of the center of outlet 13x may be higher or lower than the height position of the center of opening 12x serving as an outlet of first flow path 12, or may be the same height position.
[0020] 1.3 Third flow path (cooling water flow path) As shown in Figures 2 to 4, the third flow path 14 is provided inside the wall 11a of the tuyere body 11. "Inside the wall 11a of the tuyere body 11" refers to the space between the inner wall 11ax and the outer wall 11ay of the tuyere body 11, as shown in Figure 2. In other words, the third flow path 14 is built into the wall of the tuyere body 11. In this embodiment, the third flow path 14 is connected to a cooling water source 30, and cooling water can circulate inside the wall 11a of the tuyere body 11 via the third flow path 14. Specifically, cooling water is supplied into the inside of the wall 11a of the tuyere body 11 from the side opposite the tip 11az of the tuyere body 11 (the base side connected to the blowpipe, etc.), and after the cooling water reaches the vicinity of the tip 11az of the tuyere body 11 through the third flow path 14 provided inside the wall 11a, the cooling water is returned from the vicinity of the tip 11az to the base side of the tuyere body 11 inside the wall 11a of the tuyere body 11, thereby cooling the tuyere body 11 from the base to the tip 11az and also cooling both the inner wall 11ax and the outer wall 11ay of the tuyere body 11.
[0021] The shape of the third flow passage 14 is not particularly limited as long as it can appropriately cool the tuyere body 11. As shown in Figures 3 and 4, at least a portion of the third flow passage 14 may be spiral. That is, at least a portion of the third flow passage 14 may be provided so as to spiral inside the wall 11a of the tuyere body 11.
[0022] 2 to 4, in this embodiment, the third flow passage 14 may have an outer flow passage 14a for cooling the outer wall 11ay side of the tuyere body 11 and an inner flow passage 14b for cooling the inner wall 11ax side of the tuyere body 11 at least in the protruding portion 11x of the tuyere body 11. When the third flow passage 14 has the outer flow passage 14a and the inner flow passage 14b, the third flow passage 14 is arranged in the thickness direction of the wall 11a of the tuyere body 11 (direction D in FIG. 2). T ), and even if the wall 11a of the tuyere body 11 is thick, the cross-sectional area of the third flow passage 14 can be easily reduced. As a result, the flow rate of the cooling water in the third flow passage 14 can be more easily increased.
[0023] 2 to 4, in this embodiment, the cross-sectional area of the third flow passage 14 in the protruding portion 11x of the tuyere body 11 may be smaller than the cross-sectional area of the third flow passage 14 in the portion other than the protruding portion 11x. As described above, melting damage and the like of the tuyere body 11 are particularly likely to occur in the protruding portion 11x of the tuyere body 11. In this regard, when the cross-sectional area of the third flow passage 14 in the protruding portion 11x of the tuyere body 11 is smaller than the cross-sectional area of the third flow passage 14 in the portion other than the protruding portion 11x, it is possible to increase the flow rate of the cooling water in the protruding portion 11x of the tuyere body 11, where melting damage and the like are likely to occur, thereby improving the cooling performance in the protruding portion 11x and reducing melting damage and the like of the protruding portion 11x.
[0024] 1.4 Ribs In this embodiment, it is important that the third flow passage 14 has one or more ribs 15 that reduce the cross-sectional area (flow passage opening area) of the third flow passage 14 at least in the above-mentioned protruding portion 11x. As described above, melting damage and the like of the tuyere body 11 is likely to occur in the protruding portion 11x of the tuyere body 11. In this regard, by reducing the cross-sectional area of the third flow passage 14 in the protruding portion 11x of the tuyere body 11 by the ribs 15, the flow rate of the cooling water increases in the portion where the cross-sectional area is reduced, and cooling performance is improved. As a result, melting damage of the protruding portion 11x of the tuyere body 11 can be reduced. In this embodiment, "reducing the cross-sectional area of the third flow passage" means that the presence of the rib reduces the cross-sectional area at least in the portion between the tip of the rib and the inner wall surface of the third flow passage. 4 and 5, by providing the ribs 15 in the third flow passage 14, it is possible to increase the flow velocity of the cooling water in the gaps between the tips 15x of the ribs 15 and the inner wall surfaces 14x, 14y of the third flow passage 14. Furthermore, by increasing the flow velocity of the cooling water in the gaps, the flow velocity of the cooling water is likely to be maintained high due to inertia also downstream of the gaps.
[0025] The shape of the rib 15 is not particularly limited as long as it is possible to reduce the cross-sectional area of the third flow passage 14. As shown in Fig. 4, the rib 15 may, for example, protrude from one inner wall surface 14y (or 14x) of the opposing inner wall surfaces of the third flow passage 14 toward the other inner wall surface 14x (or 14y). In other words, the rib 15 may be provided so as to intersect with the flow direction of the cooling water in the third flow passage 14 when the rib 15 is not present.
[0026] 2 to 4, when the third flow passage 14 has, at least in the protruding portion 11x, an outer flow passage 14a that cools the outer wall 11ay side of the tuyere body 11 and an inner flow passage 14b that cools the inner wall 11ax side of the tuyere body 11, the rib 15 may be provided in a part of the outer flow passage 14a, or the rib 15 may be provided in a part of the inner flow passage 14b. For example, as shown in Fig. 5, when the rib 15 protrudes from one inner wall surface 14y of the opposing inner wall surfaces of the inner flow passage 14b toward the other inner wall surface 14x, and when the cross-sectional area (A1 + A2) of the portion of the inner flow passage 14b where the rib 15 is present is larger than the cross-sectional area A3 of the outer flow passage 14a, the cooling performance improving effect of the rib 15 is more likely to be enhanced. In this case, the cross-sectional area A2 of the inner flow passage 14b between the tip 15x of the rib 15 and the other inner wall surface 14x may be smaller than the cross-sectional area A3 of the outer flow passage.
[0027] 3 and 4, the flow direction of the cooling water in the third flow passage 14 can be controlled by the ribs 15. For example, as shown in Figures 3 and 4, the third flow passage 14 may be serpentine at least in the protruding portion 11x. That is, in the third flow passage 14, ribs 15 protruding from one inner wall surface 14y to the other inner wall surface 14x and ribs 15 protruding from the other inner wall surface 14x to the one inner wall surface 14y may be provided alternately.
[0028] The dimensions of the rib 15 can be determined appropriately depending on the target flow rate of the cooling water. For example, as shown in FIG. 6 , when the rib 15 protrudes from one inner wall surface 14y of the opposing inner wall surfaces of the third flow path 14 toward the other inner wall surface 14x, the gap width W between the tip of the rib 15 and the inner wall surface 14x may be greater than 0 mm and less than 20 mm, greater than 0 mm and less than 15 mm, or greater than 0 mm and less than 13 mm. The protruding length L of the rib 15 may be greater than 100 mm and less than 300 mm, or greater than 150 mm and less than 250 mm. The thickness T of the rib 15 may be greater than 0 mm and less than 20 mm, or greater than 0 mm and less than 15 mm.
[0029] There is no particular limitation on the number of ribs 15 provided in the third flow path 14. The number of ribs 15 may be one or more. In particular, when the third flow path 14 has a plurality of ribs 15 at least in the protruding portion 11x, better cooling performance is likely to be ensured.
[0030] 1.5 Supplementary information on the positional relationship of the ribs in the third flow channel As shown in FIG. 7 , in a blast furnace 100 according to one embodiment, the third flow passage 14 may have a first inner wall surface 14x on the tuyere tip side and a second inner wall surface 14y facing the first inner wall surface 14x. The third flow passage 14 may have one or more first ribs 15a at least in the protruding portion 11x. The first ribs 15a may protrude from the second inner wall surface 14y toward the first inner wall surface 14x. A gap 16a may exist between the tip 15ax of the first rib 15a and the first inner wall surface 14x. That is, the first rib 15a provided in the third flow passage 14 may increase the flow rate of the cooling water in the protruding portion 11x, particularly in the tuyere tip side. The protruding portion 11x, particularly in the tuyere tip side, is prone to high temperatures during operation of the blast furnace 100, making it susceptible to melting damage and the like. As shown in FIG. 7, the first rib 15a increases the flow rate of the cooling water in the protruding portion 11x, particularly on the tuyere tip side, thereby making it more difficult for the tuyere tip to be melted or damaged.
[0031] 7, in a blast furnace 100 according to one embodiment, the third flow passage 14 may have one or more second ribs 15b at least in the protruding portion 11x, and the second ribs 15b may protrude from the first inner wall surface 14x on the tuyere tip side toward the second inner wall surface 14y, and a gap 16b may exist between the tip 15bx of the second rib 15b and the second inner wall surface 14y. In particular, as shown in FIG. 7, by combining the first ribs 15a and the second ribs 15b and arranging the multiple ribs alternately, stagnation portions of cooling water (pockets where cooling water does not flow) are less likely to be formed in the third flow passage 14, and cooling water is more likely to be distributed throughout the entire third flow passage 14, which further improves cooling performance.
[0032] 1.6 Supplementary information on the positional relationship between the second flow channel and the rib As described above, when the second flow passage 13 is provided so as to penetrate the wall 11a of the tuyere body 11, the flow passage cross-sectional area of the third flow passage 14 is likely to increase. In this embodiment, excellent cooling performance is likely to be ensured by providing one or more ribs 15 in the portion of the third flow passage 14 whose cross-sectional area has increased due to the presence of the second flow passage 13. For example, as shown in Figures 8A and 8B, when the tuyere 10 is divided into two portions, a first portion 10a and a second portion 10b, by a plane Y passing through the axis X of the first flow passage 12, if the second flow passage 13 is present in the first portion 10a, the rib 15 should also be present in at least the first portion 10a (Figure 8A), and if the second flow passage 13 is present in the second portion 10b, the rib 15 should also be present in at least the second portion 10b (Figure 8B). Furthermore, if there are multiple second flow paths 13, one second flow path 13 being in the first portion 10a and the other second flow paths 13 being in the second portion 10b, it is preferable that one or more ribs 15 be provided in the first portion 10a and one or more ribs 15 be provided in the second portion 10b.
[0033] Furthermore, when reducing gas is injected into the inside of the blast furnace 100 through the second flow path 13, the distribution of the reducing gas inside the blast furnace 100 may change depending on whether the second flow path 13 is located above or below the tuyere 10. This phenomenon is particularly likely to occur when the reducing gas contains hydrogen gas (for example, when the proportion of hydrogen gas in the reducing gas is 30% by volume or more and 100% by volume or less, particularly 40% by volume or more and 100% by volume or less, particularly 50% by volume or more and 100% by volume or less, particularly 60% by volume or more and 100% by volume or less, particularly 70% by volume or more and 100% by volume or less, particularly 80% by volume or more and 100% by volume or less, and particularly particularly 90% by volume or more and 100% by volume or less). That is, when reducing gas containing hydrogen gas is injected from the upper side of the tuyere 10, the hydrogen gas rises quickly inside the blast furnace 100, and the hydrogen gas is easily supplied between the center of the blast furnace 100 and the inner wall of the blast furnace 100. On the other hand, when reducing gas containing hydrogen gas is injected from the lower side of the tuyere 10, the fluid (e.g., hot air) flowing through the first flow path 12 suppresses the rise of the hydrogen gas, and the hydrogen gas is easily supplied to the center of the blast furnace 100. The position where the reducing gas is injected through the second flow path 13 may be selected depending on the conditions required during blast furnace operation. For example, when the tuyere 10 is divided into two equal parts, an upper part and a lower part, the second flow path 13 and the rib 15 may be provided in the upper part of the tuyere 10 or in the lower part of the tuyere 10. More specifically, in FIGS. 8A and 8B, the first part 10a may be the upper part of the tuyere 10, and the second part 10b may be the lower part of the tuyere 10. That is, in this embodiment, as shown in Figures 9A and 9B, when the tuyere 10 is divided into two parts, an upper part 10c and a lower part 10d, by a plane Z passing through the axis X of the first flow path 12, if the second flow path 13 is present in the upper part 10c, the rib 15 should also be present in at least the upper part 10c (Figure 9A), and if the second flow path 13 is present in the lower part 10d, the rib 15 should also be present in at least the lower part 10d (Figure 9B).Furthermore, if there are multiple second flow paths 13, one second flow path 13 being in the upper portion 10c and the other second flow paths 13 being in the lower portion 10d, it is preferable that one or more ribs 15 be provided in the upper portion 10c and one or more ribs 15 be provided in the lower portion 10d.
[0034] 2. Hot air The hot air that can be supplied into the inside of the blast furnace 100 through the first flow path 12 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 12x serving as the outlet of the first flow path 12 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.
[0035] 3. Reducing material (solid reducing material) The reducing material that can be supplied to the inside of the blast furnace 100 through the first flow path 12 may be, for example, a solid reducing material. The solid reducing material may be any known solid reducing material used in the technical field of blast furnaces. The solid reducing material may contain carbon. The proportion of carbon in the solid reducing material is not particularly limited and may be 50% by mass or more and 100% by mass or less, or 75% by mass or more and 100% by mass or less. The solid reducing material may be, for example, pulverized coal, coke, or char obtained by carbonizing biomass or lignite. Examples of biomass that can be used include agricultural biomass (straw, sugarcane, rice bran, vegetation, coconut kernels, etc.), forestry biomass (papermaking waste, sawmill waste, thinned wood, firewood, etc.), livestock biomass (livestock waste), fisheries biomass (fishery processing residue), and waste biomass (food waste, RDF (Refuse Derived Fuel), garden trees, construction waste, sewage sludge). There are no particular limitations on the origin of lignite. Char is a carbonaceous substance that is produced when carbonaceous material is heated without achieving a softened or molten state (see JIS 0104, Terminology of Coal Utilization Technology). One type of solid reducing agent may be used alone, or two or more types may be used in combination. The solid reducing agent may have a shape and size that allows it to be supplied to the interior of the blast furnace 100 through the first flow path 12. The solid reducing agent is blown in together with a carrier gas, such as an inert gas such as nitrogen gas or air.
[0036] 4. Reducing gas The reducing gas that can be supplied to the inside of the blast furnace 100 through the second flow path 13 may be any 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 inside of the blast furnace 100, the "reducing gas" referred to in the present application is included as a gas that can generate a reducing agent (reducing component) by thermal decomposition or the like inside the blast furnace 100. In the present embodiment, the reducing gas may contain hydrogen gas. The proportion of hydrogen gas in the reducing gas may be, for example, 30% by volume or more and 100% by volume or less, 40% by volume or more and 100% by volume or less, 50% by volume or more and 100% by volume or less, 60% by volume or more and 100% by volume or less, 70% by volume or more and 100% by volume or less, 80% by volume or more and 100% by volume or less, or 90% by volume or more and 100% by volume or less. Examples of reducing gases other than hydrogen gas include at least one selected from hydrocarbon gases (e.g., methane gas), carbon monoxide gas, ammonia gas, and alcohol gases (e.g., methanol gas and ethanol gas). In the present embodiment, the reducing gas may be at least one selected from coke oven gas (COG), converter gas (LDG), blast furnace gas (BFG), natural gas (NG), synthesis gas (Syngas), liquefied petroleum gas (LPG), and dimethyl ether (DME). One of these reducing gases may be used alone, or two or more may be used in combination. The temperature of the reducing gas blown out from the outlet 13x of the second flow path 13 may be, for example, 0°C or higher and 2000°C or lower, or 25°C or higher and 1500°C or lower. The flow velocity of the reducing gas at the outlet 13x may be, for example, equal to or lower than the sonic velocity at the operating temperature of each reducing gas. Other gases may be supplied from the outlet 13x together with the reducing gas. The other gases include, for example, inert gases such as nitrogen gas.
[0037] 5.Cooling water The cooling water flowing through the third flow passage 14 may be any cooling medium containing water. The temperature of the cooling water may be any temperature that can adequately cool the inner wall 11ax and the outer wall 11ay of the tuyere body 11. Providing the second flow passage 13 (reducing gas flow passage) so as to penetrate the wall 11a of the tuyere body 11 increases the flow passage cross-sectional area of the third flow passage 14, which may result in a decrease in the flow rate of the cooling water in the third flow passage 14. However, in this embodiment, providing the third flow passage 14 with a rib 15 can restore and maintain the flow rate of the cooling water in the third flow passage 14. In the protrusion 11x, the flow rate of the cooling water in the third flow passage 14 may be, for example, 10 m / s or more, 13 m / s or more, or 15 m / s or more. There is no particular upper limit to the flow rate. The flow rate may be 25 m / s or less. As an example, the flow velocity may be 10 m / s or more and 25 m / s or less, 13 m / s or more and 23 m / s or less, or 15 m / s or more and 20 m / s or less.
[0038] 6. Supplementary Information In operation of the blast furnace 100, for example, iron ore (iron oxide), coke, etc. may be charged into the blast furnace 100 from the top thereof. Hot air and solid reducing material may be supplied from a hot stove outside the blast furnace 100 to the interior of the blast furnace 100 via the hot blast pipes and tuyere 10. Reducing gas may be supplied from a reducing gas source 20 outside the blast furnace 100 to the interior of the blast furnace 100 via the second flow path 13 and outlet 13x. The coke, solid reducing material, etc. supplied into the blast furnace 100 are combusted to generate reducing gas. The reducing gas generated by the combustion of the coke, solid reducing material, etc., or the reducing gas supplied from the outlet 13x of the second flow path 13 reduces and melts iron oxide to obtain molten iron. The molten iron is tapped from a taphole 102 provided in the lower part of the blast furnace 100. In this embodiment, by supplying reducing gas into the blast furnace 100 through the outlet 13x of the second flow path 13, the amount of coke and other solid reducing materials used can be reduced accordingly. 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), port(s), or lance(s) in addition to the above-described tuyere 10. Furthermore, the above-described tuyere 10 may have other flow paths in addition to the above-described first flow path 12, second flow path 13, and third flow path 14. The configuration of the blast furnace 100 other than the tuyere 10 is known in the art, and therefore will not be described in detail here.
[0039] 7.Tuyere for blast furnace The technology of the present disclosure has aspects as a blast furnace as well as aspects as a blast furnace tuyere. That is, a blast furnace tuyere 10 according to one embodiment has a tuyere body 11, a first flow path 12, a second flow path 13, and a third flow path 14. The tuyere body 11 has a protrusion 11x that protrudes into the interior of the blast furnace 100 when installed in the blast furnace 100. The first flow path 12 is defined by an inner wall 11ax of the tuyere body 11. The second flow path 13 is connected to a reducing gas source 20. The second flow path 13 penetrates a wall 11a of the tuyere body 11. The third flow path 14 is connected to a cooling water source 30. The third flow path 14 is provided inside the wall 11a of the tuyere body 11. The third flow path 14 has one or more ribs 15 that reduce the cross-sectional area of the third flow path 14 at least at the protrusion 11x. The details of each component are as described above, and will not be described here.
[0040] 7.Effects If the second flow path (reducing gas flow path) is provided so as to penetrate the wall of the tuyere body, the cross-sectional area of the third flow path (cooling water flow path) inside the wall of the tuyere body increases, which reduces the flow rate of the cooling water in the third flow path and may result in the necessary cooling performance not being ensured. In contrast, according to the technology disclosed herein, by providing a predetermined rib in the third flow path, the flow rate of the cooling water in the third flow path is ensured and cooling performance is easily restored and maintained. [Example]
[0041] 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 various conditions to be adopted as long as the object is achieved without departing from the gist of the present invention.
[0042] The following calculations were performed on a tuyere body in which a reducing gas flow path and a cooling water flow path are provided inside the wall. Calculations were performed to see how much the flow velocity of the cooling water in the cooling water flow path changes when ribs are provided in the cooling water flow path to narrow the flow path width near the tip of the tuyere body (a region within 250 mm from the tip) and when no ribs are provided. The calculation conditions and results are as shown in Table 1 below. Note that "flow path width" refers to the width in the direction from the tip of the tuyere (inside the blast furnace) to the base of the tuyere (outside the blast furnace), and W in Figure 6 corresponds to the "flow path width."
[0043] [Table 1]
[0044] As shown in Table 1, the flow velocity of the cooling water when no ribs were provided was 0.6 m / s, while the flow velocity of the cooling water when ribs were provided was 13.9 m / s. It was found that providing ribs in the cooling water flow path could significantly increase the flow velocity of the cooling water.
[0045] In blast furnace tuyere designs, cooling performance sufficient to prevent tuyere melting and other damage is likely to be ensured when the cooling water flow velocity is 10 m / s or higher, preferably 13 m / s or higher, and more preferably 15 m / s or higher. In this regard, we investigated the rib length required to achieve a cooling water flow velocity of 15 m / s or higher. The gap between the tip of the rib and the inner wall surface of the cooling water flow path was defined as the "tip gap width," and this was varied from 1 mm to 20 mm to confirm the maximum tip gap width that could maintain a cooling water flow velocity of 15 m / s or higher. The results are shown in Figure 10.
[0046] As shown in Figure 10, it was confirmed that if the tip gap width is 13 mm or less, the flow velocity of the cooling water can be maintained at 15 m / s or more. [Explanation of symbols]
[0047] 100 blast furnace 10 Tuyere 10a Part 1 10b Part 2 10c upper part 10d lower part 11 Tuyere body 11a Wall 11ax inner wall 11ay exterior wall 11az Tip 11x protrusion 12 First flow path 12x aperture 13 Second Flow Path 13x exit 14 Third Stream 14a Outside channel 14b Inner flow channel 14x, 14y inner wall 15 Ribs 15a First Rib 15b Second Rib 15ax, 15bx, 15x tip 20 Reducing gas source 30 Cooling water source
Claims
1. A blast furnace having a tuyere, The tuyere has a tuyere body, a first flow path, a second flow path, and a third flow path; The tuyere body has a protruding portion protruding into the inside of the blast furnace, the first flow path is defined by an inner wall of the tuyere body; the second flow path is connected to a reducing gas source; the second flow passage penetrates the wall of the tuyere body; the third flow path is connected to a cooling water source; The third flow path is provided inside the wall of the tuyere body, the third flow path has one or more ribs at least at the protrusion that reduce a cross-sectional area of the third flow path; Blast furnace.
2. 2. The blast furnace according to claim 1, The third flow path has a plurality of the ribs at least in the protruding portion. Blast furnace.
3. 2. The blast furnace according to claim 1, The rib protrudes from one of the opposing inner wall surfaces of the third flow path toward the other inner wall surface. Blast furnace.
4. 2. The blast furnace according to claim 1, The third flow path has a first inner wall surface on a tuyere tip side and a second inner wall surface opposite to the first inner wall surface, the third flow path has one or more first ribs at least in the protrusion; the first rib protrudes from the second inner wall surface toward the first inner wall surface, a gap exists between the tip of the first rib and the first inner wall surface; Blast furnace.
5. 5. The blast furnace according to claim 4, the third flow path has one or more second ribs at least in the protrusion; the second rib protrudes from the first inner wall surface toward the second inner wall surface, a gap exists between the tip of the second rib and the second inner wall surface; Blast furnace.
6. 2. The blast furnace according to claim 1, The third flow path is serpentine at least in the protruding portion. Blast furnace.
7. The blast furnace according to any one of claims 1 to 6, When the tuyere is divided into two parts, a first part and a second part, by a plane passing through the axis of the first flow path, When the second flow passage is present in the first portion, the rib is also present in at least the first portion; When the second flow path is present in the second portion, the rib is also present in at least the second portion. Blast furnace.
8. The blast furnace according to any one of claims 1 to 6, When the tuyere is divided into two parts, an upper part and a lower part, by a plane passing through the axis of the first flow path, When the second flow path is present in the upper portion, the rib is also present in at least the upper portion; When the second flow path is present in the lower portion, the rib is also present in at least the lower portion. Blast furnace.
9. 2. The blast furnace according to claim 1, The third flow path has an outer flow path that cools an outer wall side of the tuyere body at least in the protruding portion, and an inner flow path that cools an inner wall side of the tuyere body. Blast furnace.
10. 10. The blast furnace according to claim 9, The rib is provided in a part of the inner flow path. Blast furnace.
11. The blast furnace according to claim 9 or 10, the rib protrudes from one of the opposing inner wall surfaces of the inner flow path toward the other inner wall surface, a cross-sectional area of a portion of the inner flow passage from which the rib protrudes, when it is assumed that the rib does not exist, is larger than a cross-sectional area of the outer flow passage; Blast furnace.
12. A tuyere for a blast furnace, The tuyere includes a main body, a first flow path, a second flow path, and a third flow path; The tuyere body has a protruding portion that protrudes into the inside of the blast furnace when installed in the blast furnace, the first flow path is defined by an inner wall of the tuyere body; the second flow path is connected to a reducing gas source; the second flow passage penetrates the wall of the tuyere body; the third flow path is connected to a cooling water source; The third flow path is provided inside the wall of the tuyere body, the third flow path has one or more ribs at least at the protrusion that reduce a cross-sectional area of the third flow path; Tuyere for blast furnace.