JP2022154412A - Burner for powder fuel - Google Patents

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

The present disclosure relates to burners for powdered fuels.

In powder fuel burners, wear-resistant liners are sometimes used in order to prevent wear of wall surfaces due to collisions with flowing powder fuel. As such a liner, for example, Patent Document 1 discloses a ceramic piece having wear resistance. This ceramic piece includes a ceramic piece body and a stud. The ceramic piece body has holes for the studs to pass through. The ceramic piece body is fixed to the base material by welding the tip of the stud passed through the hole to the base material. A plurality of such liners are arranged adjacent to each other in the walls of the burner.

Japanese Utility Model Laid-Open No. 6-19977

In burners such as those described above, irregularities such as holes and stud heads on the surface of the liner and gaps between adjacent liners are exposed to impact with the pulverized fuel. Therefore, wear can locally develop from such locations. In such cases, the liner may fail prematurely. In addition, powdered fuel may accumulate in the irregularities and gaps. Because the liner is exposed to high temperatures, the accumulated pulverized fuel may thermally decompose into tar (liquid). Pulverized fuel adheres to such tar, and further pulverized fuel accumulates. The locations where the pulverized fuel has accumulated are exposed by impact with the pulverized fuel. Therefore, wear can progress further from the location where the powdered fuel has accumulated.

In consideration of the above problems, the present disclosure aims to provide a powder fuel burner that can improve the life of the liner.

In order to solve the above problems, a powdered fuel burner according to an aspect of the present disclosure includes an outer cylinder having a cylindrical inner wall surrounding a flow path of the powdered fuel, and at least in the central axis direction of the outer cylinder. A part thereof includes a seamless cylindrical first liner that circumferentially covers the entire inner wall of the outer cylinder.

The burner may further comprise a tubular fuel inlet communicating with the outer cylinder, and a seamless second liner covering at least a portion of the inner wall of the fuel inlet, wherein the first liner and the second liner are one It can be body type.

Moreover, in order to solve the above problems, a boiler according to an aspect of the present disclosure includes the above-described burner for powdered fuel, and a furnace to which the burner is attached.

According to the present disclosure, liner life can be improved. Accumulation of powdered fuel in the burner including the liner can be prevented, and the possibility of burnout of the burner can be reduced.

Drawing 1 is a schematic diagram showing a boiler which comprises a burner for powdered fuel concerning an embodiment. FIG. 2 : is schematic sectional drawing which shows the burner for powdered fuels which concerns on embodiment. FIG. 3 is an end view taken along line III--III in FIG.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, numerical values, and the like shown in such embodiments are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present disclosure are omitted from the drawings. do.

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

The furnace 2 burns the powdered fuel to generate high-temperature gas. Combustion of pulverized fuel produces ash. The bottom of the furnace 2 is provided with an outlet 2a for discharging ash to the outside. A flue 3 is connected to the upper part of the furnace 2 . The flue 3 guides the gas generated in the furnace 2 to the outside. The boiler 100 comprises a superheater (not shown), for example, in the upper part of the furnace 2 or the like. In the superheater, heat is exchanged between the gas generated in the furnace 2 and water. Steam is thereby generated and used to generate electricity.

A burner 10 is provided on the lower side wall or corner of the furnace 2 . A plurality of burners 10 are spaced horizontally or angularly from one another along the side walls or corners of the furnace 2 . In addition, the plurality of burners 10 may be arranged so as to be separated from each other also in the vertical direction. The tip of the burner 10 faces the furnace chamber 21 of the furnace 2 . The powdered fuel supplied to the burner 10 is injected into the furnace 2 from the tip of the burner 10 and burned by an ignition device (not shown). Thereby, a flame F is formed within the furnace 2 .

Next, the burner 10 will be described in detail.

FIG. 2 : is schematic sectional drawing which shows the burner 10 for powdered fuels which concerns on embodiment. In this disclosure, the end closer to the furnace chamber 21 will be referred to as the "leading end" (right side in FIG. 2) and the opposite end will be referred to as the "trailing end" (left side in FIG. 2) with respect to the orientation of the burner 10 and its components. ). From another point of view, in the flow of pulverized fuel, the upstream end is the "rear end" and the downstream end is the "leading end". The burner 10 includes an outer cylinder 11 , a fuel inlet portion 12 , a nozzle 13 , an inner cylinder 14 , an outer liner 15 and an inner liner 16 . Burner 10 may further comprise other components.

The outer cylinder 11 has a generally cylindrical shape and has a cylindrical inner wall 11c. The outer cylinder 11 has a cylindrical portion 11a and a tapered portion 11b along the central axis. The cylindrical portion 11a extends from the rear end of the outer cylinder 11 to an intermediate position between the rear end and the front end along the central axis. The cylindrical portion 11a has a constant diameter. The tapered portion 11b extends from the intermediate position to the tip along the central axis. The tapered portion 11b is tapered toward the tip.

FIG. 3 is an end view taken along line III--III in FIG. The fuel inlet portion 12 has, for example, a tubular shape with a substantially square cross section. The fuel inlet portion 12 is connected to the outer cylinder 11 so that its central axis is perpendicular to the central axis of the outer cylinder 11 and does not cross it. Referring to FIG. 2 , fuel inlet portion 12 is connected to the rear end of outer cylinder 11 . The fuel inlet portion 12 has an inlet 12a for powdered fuel at its upstream end (upper end in FIG. 2). The inlet 12 a communicates with the inside of the outer cylinder 11 . The inlet 12a is connected to upstream equipment by piping. 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 of, for example, 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.

Nozzle 13 is located at the tip of burner 10 . The nozzle 13 faces the furnace chamber 21 of the furnace 2 . Nozzle 13 has a generally cylindrical shape. The nozzle 13 is tapered towards its tip. The nozzle 13 is arranged coaxially with the outer cylinder 11 and connected to the tip of the outer cylinder 11 . The nozzle 13 has a powder fuel injection port 13a at its tip. The nozzle 13 is a separate member from the outer cylinder 11, and is connected to the outer cylinder 11 by fastening means such as bolts. For example, the nozzle 13 is made of cast iron that is heat resistant and wear resistant.

The inner cylinder 14 has a generally cylindrical shape and has 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 arranged 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 the central axis. The cylindrical portion 14a has approximately the same length as the cylindrical portion 11a of the outer cylinder 11 along the central axis. The cylindrical portion 14a has a constant diameter. The tapered portion 14b extends to the tip of the nozzle 13 along the central axis. The tapered portion 14b is tapered toward the tip.

Between the inner wall 11c of the outer cylinder 11 and the outer wall 14c of the inner cylinder 14, a powdered fuel flow path C1 is defined. The channel 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 an air flow path C2. 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 made of, for example, a metal such as stainless steel or a carbon material.

In the burner 10 as described above, powdered fuel is introduced from the inlet 12a of the fuel inlet portion 12 into the flow path C1. The powdered fuel is mixed by air around the central axis of the outer cylinder 11 and carried to the injection port 13a through the flow path C1. Powdered fuel is injected into the furnace chamber 21 from the injection port 13a. The outer liner 15 and the inner liner 16 are provided on the walls of the burner 10 that are frequently impinged by such pulverized fuel.

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

Referring to FIG. 2 , first liner 15 a covers inner wall 11 c of outer cylinder 11 . In this embodiment, the first liner 15a partially covers the inner wall 11c of the outer cylinder 11 in the central axis direction. Specifically, the first liner 15a covers the inner wall 11c of the entire cylindrical portion 11a and all or part of the tapered portion 11b (portion on the rear end side of the tapered portion 11b). From another point of view, the first liner 15a is provided on the outer cylinder 11 across the cylindrical portion 11a and the tapered portion 11b.

Referring to FIG. 3, the first liner 15a covers the inner wall 11c of the outer cylinder 11 along the entire circumference of the outer cylinder 11 in the circumferential direction. The first liner 15a is a seamless (ie, unitary) member. The first liner 15a is fixed to the outer cylinder 11 without using fixing means such as bolts or adhesives (the method for fixing the first liner 15a will be described later in detail). Therefore, the first liner 15a has a smooth inner peripheral surface without irregularities such as holes and grooves for arranging fixing means.

The second liner 15 b covers the inner wall 12 b of the fuel inlet portion 12 . In this embodiment, the second liner 15b is provided on a part or the entire wall surface of the inner wall 12b of the fuel inlet portion 12 having a square cross section. Specifically, the second liner 15b must be installed on the wall surface of the inner wall 12b that smoothly continues to the inner wall 11c of the outer cylinder 11, and may not be installed on other surfaces. The second liner 15b is provided from the inlet 12a to the connecting portion with the outer cylinder 11 . The second liner 15b is a seamless (ie, one-piece) member that is secured to the fuel inlet section 12 without the use of securing means. Furthermore, in this embodiment, the entire first liner 15a and second liner 15b may be an integrated member. The second liner 15b has a smooth inner surface without irregularities such as holes and grooves for arranging fixing means. If the liners 15a and 15b are made of separate members, it is necessary to finish the joint so that there is no gap or step.

Referring to FIG. 2, the inner liner 16 covers the outer wall 14c of the inner cylinder 14. As shown in FIG. In this embodiment, the inner liner 16 partially covers the outer wall 14c of the inner cylinder 14 in the central axis direction. Specifically, the inner liner 16 covers the outer wall 14c only at the cylindrical portion 14a and is not provided at the tapered portion 14b. Referring to FIG. 3, the inner liner 16 covers the outer wall 14c of the inner cylinder 14 along the entire circumference of the inner cylinder 14 in the circumferential direction. The inner liner 16 is a unitary member. The inner liner 16 is fixed to the inner cylinder 14 without the use of fixing means and has a smooth outer peripheral surface.

Outer liner 15 and 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, approximately 15 to 25 mm, but is not limited to this range.

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

The outer liner 15 is formed on the inner walls of the outer cylinder 11 and the fuel inlet portion 12 by lining. First, the outer cylinder 11 and the fuel inlet portion 12 are integrally made of a metal such as stainless steel or a carbon material. Subsequently, a portion corresponding to the outer liner 15 including the first liner 15a and the second liner 15b is formed of a synthetic resin such as expanded polystyrene. The inner surface of the synthetic resin is coated with a release paint to facilitate removal of sand, which will be described later.

The synthetic resin is then sanded inside and out. At this time, an inlet for molten metal and an outlet for molten synthetic resin, which will be described later, are formed. Then, molten metal is poured from the inlet. The synthetic resin is melted by the hot molten metal, and the molten synthetic resin is pushed out from the outlet. After the molten metal cools and solidifies, the sand is removed, leaving the outer liner 15 integrally secured to the outer cylinder 11 and the fuel inlet 12 . The inner liner 16 can also be manufactured in a similar manner as the outer liner 15 and is integrally fixed to the inner cylinder 14 . By the manufacturing method as described above, the outer liner 15 and the inner liner 16 are fixed to the outer cylinder 11 and the inner cylinder 14, respectively, without using fixing means such as bolts or adhesives, and are free from irregularities such as holes and grooves. It has a smooth surface. The method of manufacturing 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 by other methods. For example, first, the outer liner 15 is integrally formed by casting. Also, the outer cylinder 11 is prepared as a plurality of divided parts. Similarly, fuel inlet section 12 is provided as a plurality of separate pieces. Subsequently, the components of the outer cylinder 11 are assembled to the outer peripheral surface of the first liner 15a. For example, fixing 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, fixing means such as bolts may be used to connect the parts of the fuel inlet section 12 together. Further, fixing 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 . Such a configuration also makes it possible to create seamless first liner 15a and second liner 15b. Alternatively, the inner liner 16 may be made integrally by casting and then the inner cylinder 14 may be inserted inside the inner liner 16 .

The burner 10 of the boiler 100 as described above includes an outer cylinder 11 having a cylindrical inner wall 11c surrounding the flow path C1 of the powdered fuel, and at least a part of the outer cylinder 11 in the central axis direction of the outer cylinder 11. A seamless cylindrical first liner 15a that covers the entire inner wall 11c in the circumferential direction. Since the first liner 15a is a seamless member, fastening points by bolts can be eliminated or reduced. Therefore, irregularities on the surface can be eliminated or reduced, and collision and accumulation of pulverized fuel on the irregularities can be reduced. In addition, since the first liner 15a covers the entire inner wall 11c of the outer cylinder 11 in the circumferential direction, the first liner 15a does not have a gap in the circumferential direction. Therefore, it is possible to prevent the powdered fuel from colliding and accumulating in the gap. Therefore, the local progress of wear can be suppressed, and the life of the first liner 15a can be improved. Moreover, since accumulation of the powdered fuel can be reduced, thermal decomposition of the powdered fuel into tar can be suppressed. Therefore, adhesion of the powdered fuel to the tar can be reduced, and further accumulation of the powdered fuel can be prevented.

The burner 10 further includes a cylindrical fuel inlet portion 12 communicating with the outer cylinder 11, and a seamless second liner 15b covering at least a portion of the inner wall 12b of the fuel inlet portion 12. The first liner 15a and The second liner 15b is integral (outer liner 15). If the first liner 15a and the second liner 15b are separate bodies, powdered fuel may collide and accumulate in the gap between the first liner 15a and the second liner 15b. However, in this embodiment, since the first liner 15a and the second liner 15b are integrated, it is possible to prevent the powdered fuel from colliding and accumulating at the boundary between the first liner 15a and the second liner 15b. . Furthermore, accumulation of powdered fuel in the burner including the liner can be prevented, and the possibility of burnout of the burner can be reduced.

Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above embodiments. It is clear that a person skilled in the art can conceive of various modifications or modifications within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. be done.

For example, in the above-described embodiment, the first liner 15a is provided for a portion of the outer cylinder 11 in the central axis direction. 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 center axis direction of the outer cylinder 11 . Similarly, in the above embodiments, inner liner 16 is not provided at tapered portion 14b. However, in other embodiments, the inner liner 16 may be provided along the entire central axis of the inner cylinder 14 .

Also, in the above embodiment, the first liner 15a and the second liner 15b are integral. However, in other embodiments, the first liner 15a and the second liner 15b may be separate.

Further, in the above-described embodiment, the second liner 15b is provided only on part of the inner wall 12b of the fuel inlet portion 12 . However, in other embodiments, the second liner 15b may be provided over the entire inner wall 12b.

Also, in the above embodiments, no fastening means such as bolts or studs are used to secure the outer liner 15 . However, in other embodiments, the first liner 15a and the second liner 15b may be formed of separate parts, connected seamlessly at the seams, and at least partially fixed with bolts or studs.

Because this disclosure can facilitate better energy supply through better ensure access to climate change” and Goal 13 “Take urgent action to combat climate change and its impacts”.

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 Flow path of powdered fuel

Claims (3)

an outer cylinder having a cylindrical inner wall surrounding the flow path of the powdered fuel;
a seamless cylindrical first liner that covers the entire circumference of the inner wall of the outer cylinder in the circumferential direction, at least partially in the central axis direction of the outer cylinder;
A burner for powdered fuel, comprising: a tubular fuel inlet communicating with the outer cylinder;
a seamless second liner covering at least a portion of the inner wall of the fuel inlet;
further comprising
wherein the first liner and the second liner are unitary;
The burner for powdered fuel according to claim 1. A burner for powdered fuel according to claim 1 or 2;
a furnace to which the burners are attached;
a boiler.

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