EP4610566A1

EP4610566A1 - Hydrogen combustor

Info

Publication number: EP4610566A1
Application number: EP23882423.9A
Authority: EP
Inventors: Sadayuki MUTOH; Koichi FUKAI
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 2022-10-26
Filing date: 2023-10-12
Publication date: 2025-09-03
Also published as: WO2024090214A1; KR20250073398A; JP2024063444A; CN119487336A

Abstract

A hydrogen combustor includes: a hydrogen burner including a burner throat including an air passage through which combustion air flows and a fuel nozzle that ejects hydrogen fuel into the air passage or into flow of the combustion air which has been ejected from the burner throat, the hydrogen burner burning the hydrogen fuel to generate hydrogen flame; and color former adding equipment that adds a color former in powder form to the combustion air, the color former including a metal or a metal salt which causes a flame reaction with the hydrogen flame.

Description

Technical Field

The present disclosure relates to a technique of visualizing hydrogen flame in a hydrogen combustor.

Background Art

In recent years, hydrogen is attracting attention as fuel which does not emit CO₂ even when it is burned and which is low in environmental load and clean. On the other hand, light emission intensity of a visible region wavelength of hydrogen fuel is extremely weaker than that of the other gas fuel, such as LNG, and the hydrogen fuel does not generate luminous flame. Therefore, it is difficult to visually confirm hydrogen flame. In some cases, an operator of a combustion furnace determines the presence or absence of an abnormality of each of a burner, a fuel supply system, and an air supply system based on the state of the flame that is visually observed. Therefore, a technique of visualizing the hydrogen flame has been proposed.
A hydrogen combustor disclosed in PTL 1 includes: a burner that burns hydrogen to generate hydrogen flame; and a spray nozzle which is located at a position adjacent to the burner and sprays a coloring liquid that shows a flame reaction. The coloring liquid sprayed from the spray nozzle is brought into contact with the hydrogen flame generated from the burner. Then, the coloring liquid shows the flame reaction to color the hydrogen flame.

Citation List

Patent Literature

PTL 1: Japanese Laid-Open Patent Application Publication No. 2020-8244

Summary of Invention

Technical Problem

According to the hydrogen combustor of PTL 1, since the spray nozzle of the coloring liquid is located adjacent to a fuel ejecting port of the burner, the spray nozzle that is subjected to high-temperature hydrogen flame may be burned out. Moreover, to place the spray nozzle at the position adjacent to the fuel ejecting port of the burner, a significant design change of a conventional burner is required. Furthermore, to widen the spray range of the coloring liquid from the spray nozzle, means for suppressing the entrapment of circumambient air in the sprayed coloring liquid is required.
The present disclosure was made under these circumstances, and an object of the present disclosure is to provide a technique of visualizing hydrogen flame in a hydrogen combustor by a simple structure.

Solution to Problem

In order to solve the above problems, a hydrogen combustor according to one aspect of the present disclosure includes: a hydrogen burner including a burner throat including an air ejection port that ejects an air passage through which combustion air flows and a fuel nozzle that ejects hydrogen fuel into the air passage or into flow of the combustion air which has been ejected from the burner throat, the hydrogen burner burning the hydrogen fuel to generate hydrogen flame; and color former adding equipment that adds a color former in powder form to the combustion air, the color former including a metal or a metal salt which causes a flame reaction with the hydrogen flame.

Advantageous Effects of Invention

The present disclosure can provide the technique of visualizing the hydrogen flame in the hydrogen combustor by the simple structure.

Brief Description of Drawings

FIG. 1 is a diagram showing the entire configuration of a hydrogen combustor according to one embodiment of the present disclosure.
FIG. 2 is a diagram showing the entire configuration of the hydrogen combustor according to Modified Example 1.
FIG. 3 is a diagram showing the schematic configuration of the hydrogen combustor according to Modified Example 2.

Description of Embodiments

Next, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram showing the schematic configuration of a hydrogen combustor 1 according to one aspect of the present disclosure. The hydrogen combustor 1 shown in FIG. 1 is a device that burns hydrogen fuel. The hydrogen combustor 1 is included as a combustor in, for example, a furnace of a boiler or a combustion furnace. The hydrogen combustor 1 of the present embodiment includes a hydrogen burner 2 and color former adding equipment 4 that supplies a color former to combustion air of the hydrogen burner 2. The hydrogen burner 2 may perform hydrogen single-fuel combustion or hydrogen multi-fuel combustion.

Hydrogen Burner 2

The hydrogen burner 2 of the present embodiment is a typical multi-spud burner. However, the type of the hydrogen burner 2 included in the hydrogen combustor 1 according to the present disclosure is not especially limited. The hydrogen burner 2 may be, for example, a center firing burner.
The hydrogen burner 2 includes a tubular burner throat 21, fuel nozzles 22 located inside the burner throat 21, and a wind box 23 connected to the burner throat 21. An air supply pipe 25 is connected to the wind box 23, and the combustion air is supplied through the air supply pipe 25 to the wind box 23. An air register 24 is located between the wind box 23 and the burner throat 21. The amount of combustion air in the wind box 23 is adjusted by the air register 24 to an amount suitable for combustion, and such combustion air is supplied to the burner throat 21.
By an inner tube that is concentrically located inside the burner throat 21, a primary air passage 31 at an inner peripheral side of the inner tube and a secondary air passage 32 at an outer peripheral side of the inner tube are formed in the burner throat 21. A tip of the burner throat 21 serves as an air ejection port 30 from which the combustion air having flowed through the primary air passage 31 and the secondary air passage 32 is ejected.
The fuel nozzles 22 include: a center nozzle located at a center axis of the burner throat 21; and peripheral nozzles located annularly about the center nozzle. A flame stabilizer 29 is located around a tip portion of the center nozzle. The center nozzle may be an oil nozzle that atomizes oil fuel. The peripheral nozzles are located between the primary air passage 31 and the secondary air passage 32.
In the hydrogen burner 2, the combustion air which has been supplied by pressure from the wind box 23 to the burner throat 21 flows through the air passages 31 and 32 and is ejected from the air ejection port 30. A fuel gas is ejected from nozzle holes of tips of the fuel nozzles 22 into the flow of the combustion air which has been ejected from the air ejection port 30. The fuel gas is hydrogen or a hydrogen-containing gas. The hydrogen which has been ejected from the fuel nozzles 22 is mixed with the combustion air and burned to generate hydrogen flame.

Color Former Adding Equipment 4

The color former adding equipment 4 adds the color former to the combustion air before the combustion air is mixed with the hydrogen fuel. The color former adding equipment 4 according to the present embodiment supplies the color former to a passage of the combustion air in the burner throat 21 of the hydrogen burner 2.
The color former is a metal or a metal salt in powder form (or granular form) and visualizes the hydrogen flame by utilizing a flame reaction. Used as the color former is a metal, such as alkali metal, alkali earth metal, or copper, or a metal salt thereof. The metal salts of the alkali metal, such as sodium chloride (NaCl), sodium hydrogen carbonate (NaHCO₃), and sodium carbonate (Na₂CO₃), are preferable as the color former since these are available at a relatively low cost and are easy to handle.
The color former adding equipment 4 includes supply pipes 41, a feeder 42, and an operation tool 43. Supply ports 411 of the supply pipes 41 are located at the air passages 31 and 32 inside the burner throat 21 of the hydrogen burner 2. In the present embodiment, the supply ports 411 of the supply pipes 41 are annularly located so as to surround the fuel nozzles 22 such that the color former is dispersedly supplied to the air passages 31 and 32 inside the burner throat 21. According to such arrangement of the supply ports 411 of the supply pipes 41, the color former is added to the combustion air in the primary air passage 31 and/or the secondary air passage 32, but the color former may be added to the combustion air in another passage (for example, in the wind box 23) of the combustion air in the hydrogen burner 2.
The feeder 42 feeds a predetermined amount of color former to the supply pipes 41. A method of feeding the color former in powder form by the feeder 42 is not especially limited. Examples of such method include a method of feeding the color former by air, a method of feeding the color former by vibration, and a method of feeding the color former by a screw. A powder feeder having a known structure may be adopted as the feeder 42. The operation tool 43 is electrically connected to the feeder 42. When the operation tool 43 is turned on, a trigger for operation is given to the feeder 42.

Method of Visually Confirming Hydrogen Flame

According to the hydrogen combustor 1 configured as above, the hydrogen flame can be visualized at any timing during the combustion of the hydrogen in the hydrogen burner 2. Typically, the color former adding equipment 4 is in a stop state. When an operator turns on the operation tool 43 of the color former adding equipment 4, an ON command is transmitted to the feeder 42. The feeder 42 which has received the ON command feeds a predetermined amount of color former, which corresponds to the amount of color former supplied at a time, to the supply pipes 41. Thus, the color former which has been injected from the supply ports 411 of the supply pipes 41 is added to the combustion air flowing through the air passages 31 and 32 inside the burner throat 21 of the hydrogen burner 2. The color former is conveyed by the combustion air, is ejected from the air ejection port 30 together with the combustion air, and is diffused in association with the flow of the combustion air. When the color former contacts the hydrogen flame, the color former emits light of a color specific to the metal contained in the color former. For example, when sodium chloride is used as the color former, a portion of the hydrogen flame which has contacted the color former looks yellow. The operator can visually confirm the hydrogen flame, which has been visualized, to confirm the state of the hydrogen flame.

Modified Example 1

In the hydrogen combustor 1 according to the above embodiment, the color former is supplied to the air passages 31 and 32 inside the burner throat 21 of the hydrogen burner 2. However, the method of supplying the color former is not limited to this, and the color former may be supplied to a passage of the combustion air.
FIG. 2 is a diagram showing the schematic configuration of the hydrogen combustor 1 according to Modified Example 1. In the hydrogen combustor 1 according to Modified Example 1, the same reference signs are used in the drawing for the same or similar components as or to the above embodiment, and the repetition of the same explanation is avoided. As shown in FIG. 2, in the hydrogen combustor 1 according to Modified Example 1, the supply ports 411 of the supply pipes 41 of the color former adding equipment 4 are located inside the air supply pipe 25 that supplies the combustion air to the hydrogen burner 2. Then, the color former which has been supplied from the supply pipes 41 into the air supply pipe 25 is conveyed by the combustion air flowing through the air supply pipe 25 and is ejected from the air ejection port 30 together with the combustion air through the wind box 23 and the air passages 31 and 32 of the burner throat 21.

Modified Example 2

In the hydrogen combustor 1 according to the above embodiment, the hydrogen burner 2 adopts a diffusion combustion system. However, the hydrogen burner 2 may adopt a partially premixed combustion system.
FIG. 3 is a diagram showing the schematic configuration of the hydrogen combustor 1 according to Modified Example 2. In the hydrogen combustor 1 according to Modified Example 2, the same reference signs are used in the drawing for the same or similar components as or to the above embodiment, and the repetition of the same explanation is avoided. As shown in FIG. 3, the hydrogen combustor 1 according to Modified Example 2 includes the hydrogen burner 2 adopting the partial premix system. The hydrogen combustor 1 according to Modified Example 2 is configured such that a premix fuel nozzle 26 is added to the hydrogen burner 2 of the hydrogen combustor 1 according to the above embodiment. The premix fuel nozzle 26 is a fuel nozzle that ejects the hydrogen fuel into the flow of the combustion air in the burner throat 21.
The premix fuel nozzle 26 includes an outlet located at at least one of the primary air passage 31 or secondary air passage 32 of the burner throat 21. In the present modified example, the outlet of the premix fuel nozzle 26 is located at the air passage 31 but may be located at the secondary air passage 32.
In the present modified example, the premix fuel nozzle 26 is independent from the fuel nozzles 22. However, the premix fuel nozzle 26 may be a nozzle that utilizes part of the passage of the fuel nozzle 22. For example, one pipe may be utilized as the fuel nozzle 22 and the premix fuel nozzle 26 in such a manner that: at least one fuel nozzle 22 includes a small hole; and this small hole serves as the outlet of the premix fuel nozzle 26.
The fuel gas which has been ejected from the premix fuel nozzle 26 to the air passages 31 and 32 inside the burner throat 21 is mixed with the combustion air in the burner throat 21 and is ejected from the air ejection port 30. The flow rate of the fuel gas ejected from the premix fuel nozzle 26 is set such that a hydrogen concentration of a pre-mixed gas of the combustion air and the fuel gas in the burner throat 21 is less than a combustible range. The pre-mixed gas of the combustion air and the fuel gas which has been ejected from the air ejection port 30 of the burner throat 21 is mixed with the fuel gas ejected from the fuel nozzles 22 and is burned.

Conclusion

The hydrogen combustor 1 according to a first aspect of the present disclosure includes:

the hydrogen burner 2 including
- the burner throat 21 including the air passage 31, 32 through which the combustion air flows and
- the fuel nozzle 22, 26 that ejects hydrogen fuel into the air passage 31, 32 or into the flow of the combustion air which has been ejected from the burner throat 21,
- the hydrogen burner 2 burning the hydrogen fuel to generate the hydrogen flame; and
the color former adding equipment 4 that adds the color former in powder form to the combustion air, the color former including a metal or a metal salt which causes a flame reaction with the hydrogen flame.

In the hydrogen combustor 1 configured as above, the hydrogen fuel which has been ejected from the fuel nozzle 22 of the hydrogen burner 2 is mixed with the combustion air and burned to generate the hydrogen flame. The hydrogen flame and the color former which has been ejected together with the combustion air contact each other to cause the flame reaction, and the color former emits light that is visually confirmable. Thus, the hydrogen flame is visualized. In the hydrogen combustor 1, the color former in powder form is added to the combustion air. Therefore, a special nozzle or the like for the color former is not located in the vicinity of the ejecting port of the fuel nozzle 22, and burnout and the like of such nozzle does not have to be considered. Moreover, the color former adding equipment 4 adds the color former in powder form to the passage of the combustion air. Therefore, the color former adding equipment 4 can be added to the hydrogen burner 2 without a significant design change of the hydrogen burner 2 itself. Moreover, in the hydrogen burner 2, combustion and flame propagation occur at a place where the combustion air exists. Since the color former in powder form which has been ejected from the air ejection port 30 is diffused in association with the flow of the combustion air, the color former and the hydrogen flame can efficiently contact with each other. To be specific, the hydrogen combustor 1 can bring the color former and the hydrogen flame into contact with each other to color the hydrogen flame without including a special diffusing means for the color former and adjusting the diffusion of the color former. As above, the hydrogen combustor 1 can visualize the hydrogen flame by a simpler structure than conventional art.
The hydrogen combustor 1 according to a second aspect of the present disclosure is configured such that in the hydrogen combustor 1 according to the first aspect, the color former adding equipment 4 includes: the supply pipe 41 including the supply port 411 located at the passage of the combustion air; and the feeder 42 that feeds the color former to the supply pipe 41.
The hydrogen combustor 1 according to a third aspect of the present disclosure is configured such that in the hydrogen combustor 1 according to the second aspect, the supply pipe 41 of the color former adding equipment 4 includes the supply port 411 located at the air passage 31, 32.
The hydrogen combustor 1 according to a fourth aspect of the present disclosure is configured such that the hydrogen combustor 1 according to the second aspect includes the air supply pipe 25 that is connected to the hydrogen burner 2 and supplies the combustion air to the hydrogen burner 2, wherein the supply pipe 41 of the color former adding equipment 4 includes the supply port 411 located inside the air supply pipe 25.
In the hydrogen combustor 1 according to each of the second to fourth aspects, the color former is added to the combustion air before the combustion air is mixed with the hydrogen fuel. Thus, the combustion air and the color former are premixed and ejected from the air ejection port 30. Therefore, the color former can be more effectively diffused. Moreover, in the hydrogen combustor 1 according to each of the second to fourth aspects, the color former adding equipment 4 can be added without significant design changes of the hydrogen burner 2 and the air supply pipe 25.
The hydrogen combustor 1 according to a fifth aspect of the present disclosure is configured such that in the hydrogen combustor 1 according to any one of the second to fourth aspects, the color former adding equipment 4 includes the operation tool 43, and the feeder 42 feeds a predetermined amount of color former to the supply pipe 41 in accordance with an operation of the operation tool 43.
In the hydrogen combustor 1 configured as above, the color former adding equipment 4 operates in response to the operation of the operation tool 43 operated by the operator, and as a result, the hydrogen flame is visualized. Therefore, the operator can visualize the hydrogen flame at any timing.
The foregoing discussion of the present disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the present disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the present disclosure are grouped together in one embodiment for the purpose of streamlining the disclosure. However, some of the features may be combined with each other. The features of the present disclosure may be combined in alternate embodiments, configurations, or aspects other than those discussed above.

Claims

A hydrogen combustor comprising:
a hydrogen burner including
a burner throat including an air passage through which combustion air flows and

a fuel nozzle that ejects hydrogen fuel into the air passage or into flow of the combustion air which has been ejected from the burner throat,

the hydrogen burner burning the hydrogen fuel to generate hydrogen flame; and

color former adding equipment that adds a color former in powder form to the combustion air, the color former including a metal or a metal salt which causes a flame reaction with the hydrogen flame.
The hydrogen combustor according to claim 1, wherein the color former adding equipment includes:
a supply pipe including a supply port located at a passage of the combustion air; and

a feeder that feeds the color former to the supply pipe.
The hydrogen combustor according to claim 2, wherein the supply pipe of the color former adding equipment includes the supply port located at the air passage.
The hydrogen combustor according to claim 2, comprising an air supply pipe that is connected to the hydrogen burner and supplies the combustion air to the hydrogen burner, wherein
the supply pipe of the color former adding equipment includes the supply port located inside the air supply pipe.
The hydrogen combustor according to any one of claims 2 to 4, wherein:
the color former adding equipment includes an operation tool; and

the feeder feeds a predetermined amount of color former to the supply pipe in accordance with an operation of the operation tool.