Powdered fuel burners

Abstract

To provide a burner for powder fuel capable of improving a service life of a liner.SOLUTION: A burner 10 for powder fuel comprises an outer cylinder 11 having a cylindrical inner wall 11c surrounding a flow path C1 for powdered fuel, and a seamless cylindrical first liner 15a that covers the entire circumference of the inner wall 11c of the outer cylinder 11 in a circumferential direction, for at least a portion in a central axis direction of the outer cylinder 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a burner for pulverized fuels. [Background technology]

[0002] In burners for pulverized fuel, wear-resistant liners are sometimes used to prevent wear on the wall surface due to collisions with the flowing pulverized fuel. Patent Document 1, for example, discloses a wear-resistant ceramic piece as such a liner. This ceramic piece includes a ceramic piece body and a stud. The ceramic piece body has a hole for inserting the stud. The ceramic piece body is fixed to the base material by welding the tip of the stud inserted through the hole to the base material. A plurality of such liners are arranged adjacent to one another on the wall surface of the burner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 6-19977 Summary of the Invention [Problem to be solved by the invention]

[0004] In the burner described above, irregularities on the liner surface, such as holes and stud heads, and gaps between adjacent liners, are exposed to collisions with pulverized fuel. Therefore, wear can progress locally from these locations. In such cases, the liner may be damaged early. Furthermore, pulverized fuel can accumulate in the irregularities and gaps. Because the liner is exposed to high temperatures, the accumulated pulverized fuel may be thermally decomposed into tar (liquid). The tar adheres to the pulverized fuel, causing further accumulation of pulverized fuel. The locations where pulverized fuel has accumulated are exposed to collisions with the pulverized fuel. Therefore, wear can progress further from the locations where pulverized fuel has accumulated.

[0005] In consideration of the above-mentioned problems, the present disclosure aims to provide a burner for pulverized fuel that can improve the life of the liner. [Means for solving the problem]

[0006] In order to solve the above problems, a pulverized fuel burner according to one embodiment of the present disclosure includes an outer cylinder having a cylindrical inner wall surrounding a flow path of the pulverized fuel, a seamless cylindrical first liner that covers the entire inner wall of the outer cylinder in the circumferential direction for at least a portion of the central axis direction of the outer cylinder, and a cylindrical fuel inlet portion communicating with the outer cylinder; and a seamless second liner covering at least a portion of the inner wall of the fuel inlet portion; Equipped with The first and second liners are integral. .

[0008] In order to solve the above problem, a boiler according to one aspect of the present disclosure includes the above-mentioned burner for pulverized fuel and a furnace to which the burner is attached. [Effects of the Invention]

[0009] According to the present disclosure, the life of the liner can be improved, and the accumulation of pulverized fuel in the burner including the liner can be prevented, thereby reducing the possibility of burner burnout. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a boiler equipped with a pulverized fuel burner according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a pulverized fuel burner according to an embodiment. [Figure 3] 3 is an end view taken along the line III-III in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0012] FIG. 1 is a schematic diagram showing a boiler 100 equipped with a burner 10 for pulverized fuel according to an embodiment. In this embodiment, the burner 10 is applied to a boiler 100 in, for example, a thermal power plant. The burner 10 may also be applied to other facilities that use pulverized fuel. The burner 10 is used to combust pulverized fuel, such as biomass or pulverized coal, in the boiler 100. The boiler 100 includes, for example, a furnace 2, a flue 3, and a plurality of burners 10. The boiler 100 may further include other components not shown.

[0013] The furnace 2 burns pulverized fuel to generate high-temperature gas. Ash is generated by the combustion of the pulverized fuel. An outlet 2a is provided at the bottom of the furnace 2 to discharge the ash to the outside. The flue 3 is connected to the top of the furnace 2. The flue 3 guides the gas generated in the furnace 2 to the outside. The boiler 100 is equipped with a superheater (not shown), for example, above the furnace 2. In the superheater, heat is exchanged between the gas generated in the furnace 2 and water. This generates steam, which is used to generate power.

[0014] Burners 10 are provided on the side walls or corners of the lower part of the furnace 2. Multiple burners 10 are arranged along the side walls or corners of the furnace 2, spaced apart from one another horizontally or at an angle. Note that multiple burners 10 may also be arranged spaced apart from one another vertically. The tips of the burners 10 face the furnace chamber 21 of the furnace 2. Powdered fuel supplied to the burners 10 is injected into the furnace 2 from the tips of the burners 10 and combusted by an ignition device (not shown). As a result, a flame F is formed in the furnace 2.

[0015] Next, the burner 10 will be described in detail.

[0016] FIG. 2 is a schematic cross-sectional view showing a burner 10 for pulverized fuel according to an embodiment. In this disclosure, with respect to the direction of the burner 10 and its components, the end closest to the furnace chamber 21 is referred to as the "front end" (right side in FIG. 2), and the opposite end is referred to as the "rear end" (left side in FIG. 2). From another perspective, in the flow of pulverized fuel, the upstream end is the "rear end" and the downstream end is the "front end." The burner 10 includes an outer casing 11, a fuel inlet portion 12, a nozzle 13, an inner casing 14, an outer liner 15, and an inner liner 16. The burner 10 may further include other components.

[0017] The outer cylinder 11 has a generally cylindrical shape and a cylindrical inner wall 11c. The outer cylinder 11 has a cylindrical portion 11a and a tapered portion 11b along its central axis. The cylindrical portion 11a extends along the central axis from the rear end of the outer cylinder 11 to a midpoint between the rear end and the tip. The cylindrical portion 11a has a constant diameter. The tapered portion 11b extends along the central axis from the midpoint to the tip. The tapered portion 11b tapers toward the tip.

[0018] 3 is an end view taken along the line III-III in FIG. 2. The fuel inlet portion 12 has, for example, a cylindrical shape with a generally rectangular cross section. The fuel inlet portion 12 is connected to the outer cylinder 11 so that its central axis is perpendicular to, but does not intersect with, the central axis of the outer cylinder 11. Referring to FIG. 2, the fuel inlet portion 12 is connected to the rear end of the outer cylinder 11. The fuel inlet portion 12 has an inlet 12a for pulverized fuel at its upstream end (the upper end in FIG. 2). The inlet 12a communicates with the interior of the outer cylinder 11. The inlet 12a is connected to an upstream device by a pipe. In this embodiment, the outer cylinder 11 and the fuel inlet portion 12 are integral. The outer cylinder 11 and the fuel inlet portion 12 are integrally formed, for example, from a metal such as stainless steel or a carbon material. In other embodiments, the outer cylinder 11 and the fuel inlet portion 12 may be separate bodies and may be connected to each other by fastening means such as bolts.

[0019] The nozzle 13 is located at the tip of the burner 10. The nozzle 13 faces the furnace chamber 21 of the furnace 2. The nozzle 13 has a generally cylindrical shape. The nozzle 13 is tapered toward the tip. The nozzle 13 is arranged coaxially with the outer casing 11 and is connected to the tip of the outer casing 11. The nozzle 13 has an injection port 13a for the pulverized fuel at its tip. The nozzle 13 is a separate member from the outer casing 11 and is connected to the outer casing 11 by fastening means such as a bolt. For example, the nozzle 13 is made of heat-resistant and wear-resistant cast iron.

[0020] The inner cylinder 14 has a generally cylindrical shape and a cylindrical outer wall 14c. The outer diameter of the inner cylinder 14 is smaller than the inner diameter of the outer cylinder 11. The inner cylinder 14 is disposed coaxially with the outer cylinder 11 inside the outer cylinder 11. The inner cylinder 14 extends from the rear end of the outer cylinder 11 to the tip of the nozzle 13. The inner cylinder 14 has a cylindrical portion 14a and a tapered portion 14b along its central axis. The cylindrical portion 14a has a length along the central axis generally similar to that of the cylindrical portion 11a of the outer cylinder 11. The cylindrical portion 14a has a constant diameter. The tapered portion 14b extends along the central axis to the tip of the nozzle 13. The tapered portion 14b tapers toward the tip.

[0021] A flow path C1 for the pulverized fuel is defined between the inner wall 11c of the outer cylinder 11 and the outer wall 14c of the inner cylinder 14. The flow path C1 has a generally cylindrical shape. The flow path C1 communicates with the inlet 12a of the fuel inlet portion 12. An inner wall 14d of the inner cylinder 14 defines a flow path C2 for the air. The inner cylinder 14 is connected to the rear end of the outer cylinder 11 by fastening means such as bolts. The inner cylinder 14 is formed, for example, from a metal such as stainless steel or a carbon material.

[0022] In the burner 10 described above, pulverized fuel is introduced into the flow path C1 from the inlet 12a of the fuel inlet portion 12. The pulverized fuel is mixed by air around the central axis of the outer casing 11 and carried to the injection port 13a through the flow path C1. The pulverized fuel is injected from the injection port 13a into the furnace chamber 21. The outer liner 15 and the inner liner 16 are provided on the wall surfaces of the burner 10 with which the pulverized fuel frequently collides.

[0023] 2 and 3, the outer liner 15 covers the inner wall 11c (FIGS. 2 and 3) of the outer casing 11 and the inner wall 12b (FIG. 3) of the fuel inlet portion 12. Specifically, the outer liner 15 includes a first liner 15a (FIGS. 2 and 3) and a second liner 15b (FIG. 3).

[0024] 2, the first liner 15a covers the inner wall 11c of the outer cylinder 11. In this embodiment, the first liner 15a covers the inner wall 11c over a portion of the outer cylinder 11 in the central axial direction. Specifically, the first liner 15a covers the inner wall 11c over the entire cylindrical portion 11a and over either the entire or a portion of the tapered portion 11b (the portion on the rear end side of the tapered portion 11b). From another perspective, the first liner 15a is provided on the outer cylinder 11 across the cylindrical portion 11a and the tapered portion 11b.

[0025] 3, the first liner 15a covers the inner wall 11c of the outer cylinder 11 over the entire circumference in the circumferential direction of the outer cylinder 11. The first liner 15a is a seamless (i.e., one-piece) member. The first liner 15a is fixed to the outer cylinder 11 without using fixing means such as bolts or adhesive (the method for fixing the first liner 15a will be described in detail later). Therefore, the first liner 15a has a smooth inner circumferential surface without any irregularities such as holes or grooves for arranging fixing means.

[0026] The second liner 15b covers the inner wall 12b of the fuel inlet section 12. In this embodiment, the second liner 15b is provided on a portion or the entire wall surface of the inner wall 12b of the fuel inlet section 12, which has a rectangular cross section. Specifically, the second liner 15b must be provided on the wall surface of the inner wall 12b that smoothly connects to the inner wall 11c of the outer casing 11, but may not be provided on other surfaces. The second liner 15b is provided from the inlet 12a to the connecting portion with the outer casing 11. The second liner 15b is a seamless (i.e., one-piece) member and is fixed to the fuel inlet section 12 without using any fixing means. Furthermore, in this embodiment, the first liner 15a and the second liner 15b may be entirely one-piece members. The second liner 15b has a smooth inner surface without any irregularities such as holes or grooves for arranging fixing means. When the liners 15a and 15b are made of separate materials, the joints must be finished so that there are no gaps or steps.

[0027] Referring to FIG. 2, the inner liner 16 covers the outer wall 14c of the inner cylinder 14. In this embodiment, the inner liner 16 covers the outer wall 14c for a portion of the central axis direction of the inner cylinder 14. Specifically, the inner liner 16 covers the outer wall 14c only in the cylindrical portion 14a, and is not provided on the tapered portion 14b. Referring to FIG. 3, the inner liner 16 covers the outer wall 14c of the inner cylinder 14 over the entire circumferential direction of the inner cylinder 14. The inner liner 16 is an integral member. The inner liner 16 is fixed to the inner cylinder 14 without using any fixing means, and has a smooth outer peripheral surface.

[0028] The outer liner 15 and the inner liner 16 are made of, for example, wear-resistant cast iron. The thickness of each of the outer liner 15 and the inner liner 16 is, for example, about 15 to 25 mm, but is not limited to this range.

[0029] Next, a method for manufacturing the outer liner 15 will be described.

[0030] The outer liner 15 is formed by lining the inner walls of the outer casing 11 and the fuel inlet port 12. First, the outer casing 11 and the fuel inlet port 12 are made integrally from a metal such as stainless steel or a carbon material. Next, the portion corresponding to the outer liner 15, including the first liner 15a and the second liner 15b, is formed from a synthetic resin such as polystyrene foam. A release paint is applied to the inner surface of the synthetic resin to facilitate removal of sand, which will be described later.

[0031] Next, the inside and outside of the synthetic resin are covered with sand. At this time, an inlet for the molten metal and an outlet for the molten synthetic resin (described later) are formed. Next, the molten metal is poured through the inlet. The high-temperature molten metal melts the synthetic resin, and the molten synthetic resin is extruded through the outlet. After the molten metal cools and solidifies, the sand is removed, resulting in the outer liner 15, which is integrally fixed to the outer casing 11 and the fuel inlet portion 12. The inner liner 16 can be manufactured using a similar method to the outer liner 15 and is integrally fixed to the inner casing 14. Using the above manufacturing method, the outer liner 15 and the inner liner 16 are fixed to the outer casing 11 and the inner casing 14, respectively, without using fixing means such as bolts or adhesives, and have smooth surfaces free of irregularities such as holes and grooves. The manufacturing method for the outer liner 15 and the inner liner 16 is not limited to this, and the outer liner 15 and the inner liner 16 may be manufactured using other methods. For example, the outer liner 15 is first integrally formed by casting. The outer cylinder 11 is prepared as a plurality of divided parts. Similarly, the fuel inlet portion 12 is prepared as a plurality of divided parts. Next, the parts of the outer cylinder 11 are assembled to the outer peripheral surface of the first liner 15a. For example, fastening means such as bolts may be used to connect the parts of the outer cylinder 11. Similarly, the parts of the fuel inlet portion 12 are assembled to the outer peripheral surface of the second liner 15b. For example, fastening means such as bolts may be used to connect the parts of the fuel inlet portion 12. Furthermore, fastening means such as bolts may be used to connect the parts of the outer cylinder 11 and the parts of the fuel inlet portion 12. This configuration also makes it possible to produce seamless first and second liners 15a and 15b. Alternatively, the inner liner 16 may be produced integrally by casting, and then the inner cylinder 14 may be inserted inside the inner liner 16.

[0032] The burner 10 of the boiler 100 described above includes an outer cylinder 11 having a cylindrical inner wall 11c surrounding the pulverized fuel flow path C1, and a seamless cylindrical first liner 15a that completely covers the inner wall 11c of the outer cylinder 11 in the circumferential direction along at least a portion of the central axis of the outer cylinder 11. Because the first liner 15a is a seamless member, bolt fastening points can be eliminated or reduced. This eliminates or reduces surface irregularities, reducing the likelihood of pulverized fuel impinging on and accumulating in the irregularities. Furthermore, because the first liner 15a completely covers the inner wall 11c of the outer cylinder 11 in the circumferential direction, the first liner 15a does not have gaps in the circumferential direction. This prevents pulverized fuel impinging on and accumulating in the gaps. This suppresses localized wear and improves the life of the first liner 15a. Furthermore, since the accumulation of pulverized fuel can be reduced, the thermal decomposition of the pulverized fuel into tar can be suppressed, which reduces adhesion of the pulverized fuel to the tar and prevents further accumulation of the pulverized fuel.

[0033] The burner 10 further includes a cylindrical fuel inlet 12 communicating with the outer casing 11 and a seamless second liner 15b covering at least a portion of the inner wall 12b of the fuel inlet 12. The first liner 15a and the second liner 15b are integral (outer liner 15). If the first liner 15a and the second liner 15b were separate, pulverized fuel could collide and accumulate in the gap between the first liner 15a and the second liner 15b. However, in this embodiment, because the first liner 15a and the second liner 15b are integral, pulverized fuel can be prevented from colliding and accumulating at the boundary between the first liner 15a and the second liner 15b. Furthermore, pulverized fuel can be prevented from accumulating in the burner, including the liners, reducing the possibility of burner burnout.

[0034] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that such modifications also fall within the technical scope of the present disclosure.

[0035] For example, in the above embodiment, the first liner 15a is provided over a portion of the central axis direction of the outer cylinder 11. Specifically, in the above embodiment, the first liner 15a is not provided on the tip side of the tapered portion 11b. However, in other embodiments, the first liner 15a may be provided over the entire central axis direction of the outer cylinder 11. Similarly, in the above embodiment, the inner liner 16 is not provided on the tapered portion 14b. However, in other embodiments, the inner liner 16 may be provided over the entire central axis direction of the inner cylinder 14.

[0036] In addition, in the above embodiment, the first liner 15a and the second liner 15b are integral with each other, but in other embodiments, the first liner 15a and the second liner 15b may be separate.

[0037] Furthermore, in the above embodiment, the second liner 15b is provided on only a portion of the inner wall 12b of the fuel inlet portion 12. However, in other embodiments, the second liner 15b may be provided on the entire inner wall 12b.

[0038] In addition, in the above embodiment, no fastening means such as bolts or studs are used to fasten the outer liner 15. However, in other embodiments, the first liner 15a and the second liner 15b may be formed as separate parts, connected seamlessly, and at least a portion of them may be fastened by bolts, studs, or the like.

[0039] This disclosure can promote better energy supplies through better facilities, thereby contributing to the achievement of Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13, "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0040] 2 Furnace 10 Burner 11 Outer cylinder 11c Inner wall of outer cylinder 12 Fuel inlet 12b Inner wall of fuel inlet 15a First Liner 15b Second Liner 100 boiler C1 Powder fuel flow path

Claims

1. an outer cylinder having a cylindrical inner wall surrounding a flow path for the powdered fuel; a seamless cylindrical first liner that covers the inner wall of the outer cylinder in a circumferential direction over the entire circumference of the inner wall of the outer cylinder along at least a portion of the central axis of the outer cylinder; a cylindrical fuel inlet portion communicating with the outer cylinder; a seamless second liner covering at least a portion of an inner wall of the fuel inlet portion; Equipped with the first liner and the second liner are integral; Burner for pulverized fuel.

2. A burner for pulverized fuel according to claim 1; a furnace in which the burner is mounted; A boiler equipped with

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