Ammonia combustion burner

Abstract

To provide an ammonia combustion burner that has a simple structure and inexpensive manufacturing cost, and is excellent in ammonia combustion efficiency.SOLUTION: A burner burns ammonia as fuel in a metal heat treatment furnace 1, and comprises: a center nozzle 11 that is arranged in a center, and injects ammonia; a plurality of side nozzles 12 that are arranged on the outer peripheral side of the center nozzle 11, and injects hydrocarbon-based fuel; and an annular air injection nozzle 13 that is arranged so as to surround the plurality of side nozzles 12 from the outside, and has an annular air injection port 13a that injects air so as to surround the hydrocarbon-based fuel injected from the plurality of side nozzles 12 from the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a burner that burns ammonia as fuel. [Background technology]

[0002] In recent years, ammonia has been attracting attention as a new fuel from the perspective of curbing global warming because it does not produce carbon dioxide when burned. However, it is known that mixing ammonia with fossil fuels or burning ammonia alone increases nitrogen oxide emissions.

[0003] For example, the combustion device described in Patent Document 1 was invented to solve the problem of increased nitrogen oxides when coal is burned with ammonia added.

[0004] To compensate for this, as shown in Fig. 6, instead of changing the structure of the burner itself, a structure is adopted in which, in addition to ammonia supply means 22 that supplies ammonia to mixed gas flow path 21 formed in the burner, control means 23 that controls the supply of ammonia depending on the operating conditions, distribution means 25 that distributes ammonia sent from ammonia supply means 22 to mixed gas flow path 21 and introduction part 24, and a plurality of corresponding distribution conveyance paths 26 are provided outside the burner. Then, the distribution state of ammonia in distribution means 25 is controlled by control means 23. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7020759 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the combustion burner described in Patent Document 1 has ammonia supply means 22 for sending ammonia to a mixed gas flow path 21 formed in a nozzle, as well as distribution means 25 and a plurality of distribution and conveyance paths 26 associated therewith, and furthermore, control means 23 for controlling distribution means 25, so that the structure is complex and large-scale, and there are problems in that the manufacturing cost is high.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ammonia combustion burner that has a simple structure, is inexpensive to manufacture, and has excellent ammonia combustion efficiency. [Means for solving the problem]

[0008] In order to achieve the above object, the ammonia combustion burner (10) of the present invention comprises: A burner for burning ammonia as fuel in a metal heating furnace (1), a center nozzle (11) disposed at the center and spraying ammonia; a plurality of side nozzles (12) arranged on the outer circumferential side of the center nozzle (11) and configured to inject hydrocarbon fuel; an air injection nozzle (13) having an annular air injection port (13a) that is arranged so as to surround the plurality of side nozzles (12) from the outside and that injects air so as to surround the hydrocarbon fuel injected from the plurality of side nozzles (12) from the outside; Preparation, Ammonia is mixed with the hydrocarbon fuel injected from the plurality of side nozzles (12). It is characterized by:

[0009] The ammonia combustion burner (10) of the present invention further comprises: A burner for burning ammonia as fuel in a metal heating furnace (1), a center nozzle (11) disposed at the center and spraying ammonia; a plurality of side nozzles (12) arranged on the outer circumferential side of the center nozzle (11) and configured to inject hydrocarbon fuel; an air injection nozzle (13) having a plurality of air injection ports (17a) that are discretely arranged on the same circumference so as to surround all of the plurality of side nozzles (12) from the outside, and that injects air so as to surround from the outside the hydrocarbon fuel injected from the plurality of side nozzles (12); Preparation, Ammonia is mixed with the hydrocarbon fuel injected from the plurality of side nozzles (12). It is characterized by:

[0015] Here, the symbols in parentheses indicate corresponding elements or items shown in the drawings and in the detailed description to be described later. [Effects of the Invention]

[0016] The ammonia combustion burner of the present invention is configured with a center nozzle located at the center, a plurality of side nozzles located on the outer periphery of the center nozzle, and an annular air injection nozzle having annular air injection ports that inject air so as to surround from the outside the hydrocarbon fuel injected from the center nozzle and side nozzles. Therefore, the structure is simpler than in conventional technology, and manufacturing costs can be kept low. Since ammonia has a low combustion speed, the flow velocity distribution of the center nozzle and side nozzles can be set arbitrarily, making it possible to stabilize combustion.

[0017] That is, the ammonia injection burner of the present invention has a center nozzle, side nozzles, and air injection nozzles formed in the burner itself to promote the combustion of ammonia. Therefore, unlike the prior art, there is no need to provide a distribution means or control means outside the burner. As a result, it is excellent in terms of structure and manufacturing cost, and also in ammonia combustion efficiency.

[0018] Furthermore, since air is injected from the annular air injection port of the air injection nozzle so as to surround the hydrocarbon fuel injected from the multiple side nozzles, the ammonia can be burned at an appropriate rate by the flames of the side nozzles.

[0019] Instead of providing an annular air injection nozzle, it is also possible to provide an air injection nozzle having a plurality of air injection nozzles that are discretely arranged on the same circumference so as to surround all of the plurality of side nozzles from the outside, and that injects air so as to surround from the outside the hydrocarbon fuel injected from the plurality of side nozzles.

[0020] Instead of providing an annular air injection port, an air injection nozzle may be provided which is discretely arranged on the same circumference so as to surround the plurality of side nozzles from the outside, and which has air injection ports which inject air so as to surround from the outside the hydrocarbon fuel injected from the plurality of side nozzles or the gas mixture of hydrocarbon fuel and ammonia.

[0021] Furthermore, according to the present invention, ammonia is mixed with the hydrocarbon fuel injected from the plurality of side nozzles, so that a larger amount of ammonia can be burned efficiently.

[0026] As described above, the above-mentioned patent documents do not describe at all the configuration of the ammonia combustion burner regarding the arrangement of the center nozzle, the multiple side nozzles, and the annular air injection ports that inject air. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a partial cross-sectional view showing a main part of a non-ferrous metal heat treatment furnace equipped with an ammonia combustion burner according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the ammonia combustion burner shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line XX in FIG. 2. [Figure 4] FIG. 10 is an explanatory diagram showing that the distance D between the center nozzle and each side nozzle is equal, and that the distance R between each side nozzle is equal. [Figure 5] FIG. 10 is an explanatory diagram showing that the distance P between the air injection nozzle and each side nozzle is shorter than the distance Q between each side nozzle and the center nozzle. [Figure 6]FIG. 1 is a schematic side view showing an ammonia combustion burner according to a conventional example. [Figure 7] FIG. 2 is a front view of another ammonia-combustion burner according to an embodiment of the present invention. [Figure 8] FIG. 10 is a partial cross-sectional view showing a main part of a non-ferrous metal heat treatment furnace equipped with yet another ammonia combustion burner according to an embodiment of the present invention. [Figure 9] FIG. 9 is a front view of the ammonia combustion burner shown in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0028] An ammonia combustion burner 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0029] As shown in FIG. 1, the ammonia combustion burner 10 according to this embodiment is a burner that is provided in the furnace body 2 of the metal heating furnace 1 and burns ammonia as fuel, and includes a center nozzle 11, a side nozzle 12, and an air injection nozzle 13.

[0030] The center nozzle 11 has a circular front shape and is disposed at the center of the ammonia combustion burner 10, and injects ammonia supplied from the ammonia supply device 14 into the furnace body 2 from its ammonia injection port 11a.

[0031] The side nozzles 12 are also circular in shape from the front, and are provided in multiple numbers (four in this embodiment) on the outer periphery of the center nozzle 11. The hydrocarbon fuel supplied from the hydrocarbon fuel supply device 15 is injected into the interior of the furnace body 2 from the side nozzle injection ports 12a. Hydrocarbon fuels are fuels made of substances consisting of carbon and hydrogen, and include methane, acetylene, ethylene, naphthalene, etc. In this embodiment, methane is used, but instead, for example, city gas containing hydrocarbon fuels can be used.

[0032] As shown in Figure 4, the four side nozzles 12 are all spaced the same distance D from the center nozzle 11, and are arranged circumferentially at equal intervals R on the outer periphery of the center nozzle 11, symmetrically positioned above, below, left, and right of the center nozzle 11. The number of side nozzles 12 is not limited to four. The side nozzles 12 can be arranged at different distances from the center nozzle 11, and can also be arranged at different intervals in the circumferential direction.

[0033] The air injection nozzle 13 is annular (circular) in shape at the front and is arranged so as to surround the plurality of side nozzles 12 from the outside. This air injection nozzle 13 is also provided with an annular (circular) air injection port 13a, from which air supplied from an air supply device 16 is continuously injected so as to surround from the outside the methane injected from the multiple side nozzles 12. Some of the air may also be supplied to the side nozzles 12.

[0034] Furthermore, as shown in FIG. 5, in this ammonia combustion burner 10, the distance P between the air injection nozzle 13 and each side nozzle 12 on the line connecting the center of the center nozzle 11 and the center of each side nozzle 12 is set to be shorter than the distance Q between each side nozzle 12 and the center nozzle 11.

[0035] The ammonia combustion burner 10 according to this embodiment can be operated as follows. First, ammonia from the center nozzle 11 (ammonia injection nozzle 11a), methane from the side nozzle 12 (side nozzle injection nozzle 12a), and air from the air injection nozzle 13 (annular air injection nozzle 13a) are injected simultaneously or one after the other, and the methane is ignited and burned by an ignition device (not shown).

[0036] At this time, the methane can be effectively combusted by the oxygen in the air injected from the air injection nozzle 13, thereby efficiently combusting the ammonia injected from the center nozzle 11. In addition, since the air from the air injection nozzle 13 is injected so as to surround the methane injected from the side nozzle 12, the methane is pushed in the direction of the ammonia by this injection force. Therefore, ammonia can be burned more efficiently using the heat of methane.

[0037] In addition, all of the side nozzles 12 are arranged at equal distances D from the center nozzle 11, so the thermal power of the methane can be applied evenly to all of the ammonia injected from the center nozzle 11. Therefore, the ammonia can always be burned uniformly and efficiently.

[0038] Furthermore, since the side nozzles 12 are arranged at equal intervals R in the circumferential direction on the outer circumferential side of the center nozzle 11, the thermal power of the methane can be applied evenly to the ammonia injected from the center nozzle 11. Therefore, the ammonia can be burned evenly and efficiently.

[0039] Furthermore, since the number of side nozzles 12 is four, the methane injected from the side nozzles 12 can be made to react with the ammonia evenly from four locations (top, bottom, left, and right) for combustion, thereby further improving combustion efficiency.

[0040] Furthermore, the distance P between the air injection nozzle 13 and each side nozzle 12 is set shorter than the distance Q between each side nozzle 12 and the center nozzle 11, so the injection force of the air acting on the methane is greater than the injection force of the ammonia acting on the methane. This also pushes the methane toward the ammonia, resulting in more efficient combustion of the ammonia.

[0041] Since the air injected from the air injection nozzle 13 is continuously supplied, a cylindrical wall of air (a so-called air curtain) is formed. Therefore, the methane can be kept inside the cylindrical wall without escaping to the outside. This allows the thermal power of the methane to promote efficient combustion of ammonia.

[0042] As described above, the ammonia combustion burner 10 according to this embodiment is composed of a center nozzle 11 arranged at the center thereof, a plurality of side nozzles 12 arranged on the outer periphery thereof, and air injection nozzles 13 surrounding them, and does not include any components outside the burner 10 for promoting the combustion of ammonia. Therefore, the structure is simple, and the manufacturing cost can be kept low. Furthermore, the simple structure makes it difficult for breakdowns to occur, and as a result, ammonia can be burned stably at all times.

[0043] In this embodiment, the hydrocarbon fuel is injected from the side nozzles 12. Alternatively, the side nozzles 12 may inject a gas mixture of hydrocarbon fuel and ammonia. Furthermore, in this embodiment, the air injection nozzle 13 is provided in an annular shape that is arranged to surround the multiple side nozzles 12 from the outside, and has an annular air injection port 13a that injects air so as to surround from the outside the hydrocarbon fuel injected from the multiple side nozzles 12. However, instead of this, as shown in FIG. 7 , the air injection nozzle 13 may be provided that is discretely arranged on the same circumference so as to surround from the outside all of the multiple side nozzles 12, and has a plurality of air injection ports 17a that injects air so as to surround from the outside the hydrocarbon fuel injected from the multiple side nozzles 12.

[0044] Furthermore, as shown in Figures 8 and 9, air may be injected from a second air supply device 19, separate from the air supplied from the air supply device 16, through an air injection port 18a of a second air injection nozzle 18 provided in a position close to the multiple side nozzles 12.

[0045] The ammonia combustion burner according to this embodiment can be used in any field where ammonia is used as fuel (for example, thermal power generation). [Explanation of symbols]

[0046] 1. Metal heat treatment furnace (non-ferrous metal heat treatment furnace) 2 Furnace body 10 Ammonia combustion burner 11 Center nozzle 11a Ammonia injection nozzle 12 Side nozzle 12a Side nozzle nozzle 13 Air injection nozzle 13a Annular air jet nozzle 14 Ammonia supply device 15 Hydrocarbon fuel supply system 16 Air supply device 17a Air injection nozzle 18 Second air injection nozzle 18a Air nozzle 19 Second air supply device 20 Ammonia combustion burner 21 mixed gas flow path 22 Ammonia supply means 23 Control Means 24 Input section 25 Means of distribution 26 Distribution conveyance route D Distance between the center nozzle 11 and each side nozzle 12 P: Distance between the air injection nozzle 13 and each side nozzle 12 Q Distance between each side nozzle 12 and the center nozzle 11 R Distance between each side nozzle 12

Claims

1. A burner for burning ammonia as fuel in a metal heat treatment furnace, comprising: A center nozzle is located in the center and sprays ammonia. a plurality of side nozzles arranged on an outer circumferential side of the center nozzle and configured to inject hydrocarbon fuel; an air injection nozzle having an annular air injection port that is arranged so as to surround the plurality of side nozzles from the outside and that injects air so as to surround the hydrocarbon-based fuel injected from the plurality of side nozzles from the outside, An ammonia combustion burner characterized in that ammonia is mixed with the hydrocarbon fuel injected from the plurality of side nozzles.

2. A burner for burning ammonia as fuel in a metal heat treatment furnace, comprising: A center nozzle is located in the center and sprays ammonia. a plurality of side nozzles arranged on an outer circumferential side of the center nozzle and configured to inject hydrocarbon fuel; an air injection nozzle having a plurality of air injection ports that are discretely arranged on the same circumference so as to surround all of the plurality of side nozzles from the outside, and that injects air so as to surround from the outside the hydrocarbon-based fuel injected from the plurality of side nozzles; An ammonia combustion burner characterized in that ammonia is mixed with the hydrocarbon fuel injected from the plurality of side nozzles.

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