Ammonia combustion equipment

Abstract

To burn ammonia sufficiently to prevent unburnt ammonia from being left, and prevent NOx from occurring during combustion of ammonia, when mixing ammonia and air and burning them.SOLUTION: In an ammonia combustion facility where ammonia NH3 is mixed with air and burned, an air ratio for burning the ammonia NH3 is set to a range of 0.95 to 0.99.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ammonia combustion facility that mixes ammonia with air and burns it. In particular, the present invention is characterized in that when ammonia is mixed with air and burned, the ammonia is sufficiently burned to prevent unburned ammonia from remaining, and NOx is prevented from being generated during the combustion of ammonia. [Background technology]

[0002] 2. Description of the Related Art Combustion equipment that mixes fuel with combustion air and burns it generally uses hydrocarbon fuel as the fuel.

[0003] However, when hydrocarbon fuel is mixed with combustion air and burned in this manner, there is a problem in that a large amount of greenhouse gases such as carbon dioxide (CO2) is generated.

[0004] In recent years, there has been a demand for reducing greenhouse gases such as carbon dioxide (CO2), and the use of fuels other than hydrocarbon fuels has been considered.

[0005] Furthermore, it has been known for some time that ammonia has been used as a fuel. However, ammonia has poor combustibility compared to hydrocarbon fuels, making it difficult to completely burn it, and unburned ammonia is likely to remain. Furthermore, if ammonia is burned vigorously to reduce the amount of unburned ammonia, the flame temperature increases, resulting in an increase in the amount of NOx generated.

[0006] Patent Document 1 proposes that when ammonia, which is a low-combustibility fuel having poor combustibility as described above, is mixed with combustion air and burned, ammonia premixed with combustion air is selectively used to enhance the combustibility of ammonia.

[0007] However, even when ammonia, which is a low-combustibility fuel, is premixed with combustion air and used selectively in this way, there still remain problems that the ammonia is not sufficiently burned and unburned ammonia remains, or that when the ammonia is burned strongly to reduce the amount of unburned ammonia, the flame temperature becomes high and the amount of NOx generated increases.

[0008] Furthermore, Patent Document 2 proposes that when a substance containing sulfur components, such as natural gas or pulverized coal, is burned as fuel, ammonia is injected from an ammonia injection port along the inner wall surface of a wall portion where no burner is installed, and the ammonia is burned near the inner wall surface of the wall portion, thereby preventing the wall portion from being eroded by hydrogen sulfide generated by the combustion of the sulfur components.

[0009] However, in the method disclosed in Patent Document 2, when ammonia itself is combusted as described above, the effect of preventing unburned ammonia from remaining or an increase in the amount of NOx generated cannot be obtained. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-130619 [Patent Document 2] Japanese Patent Application Publication No. 2020-139700 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0011] An object of the present invention is to solve the above-mentioned problems in ammonia combustion facilities in which ammonia is mixed with air and burned.

[0012] That is, an object of the present invention is to sufficiently combust ammonia to prevent unburned ammonia from remaining when ammonia is mixed with air and combusted in the ammonia combustion facility as described above, and to prevent NOx from being generated during the combustion of ammonia. [Means for solving the problem]

[0013] The present invention Related ammonia combustion equipment In order to solve the above-mentioned problems, in an ammonia combustion facility in which ammonia is mixed with air and burned, A guide pipe for guiding the ammonia discharged from the ammonia discharge pipe into the furnace is provided on the outer periphery of the tip of the ammonia discharge pipe for discharging the ammonia, and air is introduced into the guide pipe through an air inlet between the ammonia discharge pipe and the guide pipe. The ammonia and air are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide pipe, and combusted. An air introduction adjusting means is provided for adjusting the size of the air inlet between the ammonia discharge pipe and the guide pipe, and for adjusting the air ratio for combusting the ammonia in the range of 0.95 to 0.99. .

[0014] Here, the inventors conducted an experiment in which ammonia was mixed with air and burned, and investigated the relationship between the air ratio at which ammonia was burned, the amount of unburned ammonia that remains when ammonia is not sufficiently burned, and the amount of NOx generated when ammonia is burned.As a result, as shown in Figure 1, it was found that as the air ratio decreases, the amount of NOx generated decreases and becomes zero, and at the same time, there is a point at which unburned ammonia, which was zero, is generated, in other words, a point at which the generation of NOx and the generation of unburned ammonia both approach zero.

[0015] Furthermore, the results of the experiment showed that the point at which both NOx emissions and unburned ammonia emissions approach zero is when the air ratio for burning ammonia is in the range of 0.95 to 0.99. In Figure 1, Experiment A shows the changes in the amount of NOx emitted and the amount of unburned ammonia emitted when the air ratio for burning ammonia was 0.95, the lowest, while Experiment B shows the changes in the amount of NOx emitted and the amount of unburned ammonia emitted when the air ratio for burning ammonia was 0.99, the highest.

[0016] For this reason , the present invention Related ammonia combustion equipment In this case, As mentioned aboveIn an ammonia combustion facility in which ammonia is mixed with air and burned, a guide pipe is provided on the outer periphery of the tip of the ammonia discharge pipe that discharges the ammonia, for guiding the ammonia discharged from the ammonia discharge pipe into a furnace, air is introduced into the guide pipe through an air inlet between the ammonia discharge pipe and the guide pipe, and the ammonia and air are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide pipe to be combusted, with the air ratio for combusting the ammonia being set in the range of 0.95 to 0.99.

[0017] and, As mentioned above When ammonia is discharged from the ammonia discharge pipe into a guide pipe provided on the outer periphery of the tip of the ammonia discharge pipe, air is introduced into the guide pipe through an air inlet between the ammonia discharge pipe and the guide pipe, and ammonia and air are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide pipe for combustion, the flame spreads radially near the inner wall surface of the furnace. Therefore, even when ammonia with low flammability is jetted into the furnace and combusted, it is possible to prevent the flame from extending long into the furnace and directly hitting the workpiece in the furnace, which would result in poor finish of the workpiece, as in the conventional case.

[0018] Also, this In ammonia combustion facilities teeth As described above, the air ratio for burning ammonia was set in the range of 0.95 to 0.99, so the amount of unburned ammonia and the amount of NOx generated during combustion were also reduced.

[0019] In addition, the above In ammonia combustion facilities teeth When the ammonia and air introduced into the guide tube as described above are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide tube, and combusted, the air ratio for combusting the ammonia is adjusted to be in the range of 0.95 to 0.99. 、 The size of the air introduction section between the ammonia discharge pipe and the guide pipe is adjusted by an air introduction adjusting means. We have set up .

[0020] Furthermore, when adjusting the air ratio for burning ammonia to be in the range of 0.95 to 0.99 as described above, an air guide section for guiding air into the furnace can be provided on the outer periphery of the guide tube, and the air guided into the furnace through the air guide section can be mixed with the ammonia and air jetted radially into the furnace from a plurality of radial jets provided on the outer periphery of the tip of the guide tube as described above, and combusted. Also, the amount of air guided into the furnace through the air guide section can be adjusted by guide air adjustment means. [Effects of the Invention]

[0021] In the present invention Ammonia combustion equipment In the above, the air ratio for burning ammonia is set to the range of 0.95 to 0.99, so that the ammonia is sufficiently burned during combustion as described above, and it is possible to prevent unburned ammonia from remaining, and also to prevent the generation of NOx during the combustion of ammonia.

[0022] In addition, in the present invention Ammonia combustion equipment In the above-mentioned method, ammonia and air are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide tube, and combusted. Therefore, even when ammonia, which has low flammability, is jetted into the furnace and combusted, the flame spreads radially near the wall of the furnace, preventing the flame from extending far into the furnace and directly hitting the material to be treated inside the furnace, which would result in a poor finish of the material, as was the case in the past. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing the relationship between the air ratio at which ammonia is combusted, the amount of unburned ammonia that remains without being sufficiently burned, and the amount of NOx generated during the combustion of ammonia in the ammonia combustion equipment of the present invention. [Figure 2]FIG. 1 is a schematic explanatory diagram showing a state in which ammonia is discharged from an ammonia discharge pipe into a guide pipe provided on the outer periphery of the tip of the ammonia discharge pipe, air is introduced into the guide pipe through an air inlet between the ammonia discharge pipe and the guide pipe, and ammonia and air are jetted radially into a furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide pipe, and burned, in an ammonia combustion facility according to an embodiment of the present invention. [Figure 3] 3 is an explanatory cross-sectional view taken along line A-A, showing a state in which a guide section for guiding air into a furnace is provided on the outer periphery of a guide tube in the ammonia combustion equipment according to the embodiment shown in FIG. 2, and the amount of air guided into the furnace through the air guide section is adjusted by a guide air adjustment means. BEST MODE FOR CARRYING OUT THE INVENTION

[0024] Hereinafter, an ammonia combustion facility according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the ammonia combustion facility according to the present invention is not limited to the following embodiment, and can be appropriately modified and implemented within the scope of the invention.

[0025] In the ammonia combustion facility according to the embodiment of the present invention, as shown in FIG. 2, an ammonia discharge pipe 20 for discharging ammonia NH3 is inserted into the center of a support plate 12b supported by supports 12a attached to mounting members 11 provided on an outer wall surface 10a of a furnace 10.

[0026] In addition, in the mounting member 11, a guide pipe 30 for guiding ammonia NH3 discharged from the ammonia discharge pipe 20 into the furnace 10 is attached to the center of a protruding portion 11a that is provided so as to protrude outward in a concave shape from the outer wall surface 10a of the furnace 10, so as to be located on the outer periphery of the tip of the ammonia discharge pipe 20, and a plurality of radiation nozzles 31 are provided on the outer periphery of the tip of the guide pipe 30 led into the furnace 10 in the radial direction.

[0027] Here, in the ammonia combustion equipment of this embodiment, a threaded portion 22 is provided on the outer periphery of the ammonia discharge pipe 20, and an air introduction adjusting means 40 is provided that rotates in mesh with the threaded portion 22 on the outer periphery of the ammonia discharge pipe 20 and moves in the axial direction of the ammonia discharge pipe 20, and the size of the air introduction portion S1 between the ammonia discharge pipe 20 and the guide pipe 30 is adjusted by this air introduction adjusting means 40.

[0028] In addition, the inner diameter of the discharge port 21 at the tip of the ammonia discharge pipe 20 is tapered toward the direction in which the ammonia NH3 is ejected, so that the ammonia NH3 introduced into the ammonia discharge pipe 20 is ejected forcefully from the contracted discharge port 21 into the guide pipe 30.

[0029] In addition, by combining this with a diffuser structure in which the inner diameter of the flow path 33 in the guide pipe 30 is gradually contracted in the flow direction and then expanded again, an ejector effect is created, allowing for even more powerful ejection.

[0030] When ammonia NH3 is forcefully ejected from the outlet 21 of the ammonia ejection pipe 20 into the guide pipe 30 in this manner, air Air is sucked into the space between the ammonia ejection pipe 20 and the guide pipe 30 through the air inlet S1, and the sucked air Air is mixed with the ammonia NH3 ejected into the guide pipe 30 and is introduced to the tip of the guide pipe 30, and is ejected in the radial direction near the inner wall surface 10b of the furnace 10 from the plurality of radial ejection ports 31 provided on the outer periphery of the tip of the guide pipe 30.

[0031] In addition, in the ammonia combustion equipment of this embodiment, an air guide section 32 that guides air (Air) into the furnace 10 is provided on the outer periphery of the guide pipe 30, and as a guide air adjustment means for adjusting the amount of air (Air) that is guided to the air guide section 32, a plurality of introduction holes 51 that guide air (Air) to the air guide section 32 are provided in the protrusion 11a of the mounting member 11, and air adjustment holes 53 are provided in a ring-shaped rotating plate 52 that rotates in contact with the surface of the protrusion 11a, so as to correspond to each introduction hole 51 provided in the protrusion 11a.

[0032] To adjust the amount of air (Air) guided into the furnace 10 through the air guide section 32, as shown in FIG. 3, the rotating plate 52 is rotated to change the area of ​​the connecting portion between the inlet hole 51 provided in the protruding section 11a and the air adjustment hole 53 provided in the rotating plate 52, thereby adjusting the amount of air guided into the air guide section 32 through the inlet hole 51 and the air adjustment hole 53. In this way, an appropriate amount of air (Air) is supplied into the furnace 10 through the air guide section 32.

[0033] Here, in the ammonia combustion equipment of this embodiment, as described above, ammonia NH3 is injected into the guide pipe 30 from the discharge port 21 of the ammonia discharge pipe 20, and air Air is sucked into the space between the ammonia discharge pipe 20 and the guide pipe 30 through the air introduction section S1. While the air Air is mixed together with the ammonia NH3 in the guide pipe 30, the ammonia NH3 and air Air are injected radially into the furnace 10 from a plurality of radial injection ports 31 provided on the outer periphery of the tip of the guide pipe 30 along the inner wall surface 10b of the furnace 10, and an appropriate amount of air Air is supplied into the furnace 10 through the air guide section 32 on the outer periphery side of the guide pipe 30. With this air Air added, the ammonia NH3 is combusted at an air ratio in the range of 0.95 to 0.99.

[0034] In this way, as shown in FIG. 1, the amount of unburned ammonia (NH3) generated during combustion and the amount of NOx generated can be reduced. In particular, when the air ratio for burning ammonia (NH3) is set to about 0.97, the amount of unburned ammonia generated and the amount of NOx generated can be significantly reduced.

[0035] Furthermore, in the ammonia combustion equipment of this embodiment, as described above, ammonia NH3 and air Air are jetted radially into the furnace 10 from the plurality of radial jets 31 provided on the outer periphery of the tip of the guide pipe 30 along the inner wall surface 10b of the furnace 10, and an appropriate amount of air Air is supplied into the furnace 10 through the air guide section 32 on the outer periphery of the guide pipe 30 to combust the ammonia NH3. As a result, the flame spreads radially near the inner wall surface 10b of the furnace 10, preventing the flame from extending too far into the furnace 10. When a workpiece (not shown) is heat-treated in the furnace 10, the flame is prevented from directly hitting the workpiece, which can result in poor finish of the workpiece.

[0036] In the ammonia combustion equipment of this embodiment, as described above, ammonia NH3 and air Air are jetted radially into the furnace 10 along the inner wall surface 10b of the furnace 10 from the multiple radial jets 31 provided on the outer periphery of the tip of the guide tube 30, but the ammonia combustion equipment of the present invention is not limited to the above.

[0037] For example, although not shown, a mixture of ammonia NH3 and air may be sprayed into the furnace from the tip of a spray pipe (not shown). In this case, too, by burning ammonia NH3 at an air ratio in the range of 0.95 to 0.99 as described above, the amount of unburned ammonia NH3 and the amount of NOx generated during combustion can be reduced. [Explanation of symbols]

[0038] 10: Furnace 10a: Exterior wall surface 10b: Inner wall surface 11: Mounting material 11a:Protrusion 12a: Post 12b: Support plate 20: Ammonia discharge pipe 21:Discharge port 22: Threaded part 30: Guide tube 31: Radiation spout 32: Air guide section 33: Flow path 40: Air intake adjustment means 51: Introduction hole 52: Rotating plate 53: Air adjustment hole Air: NH3: Ammonia S1: Air intake section

Claims

1. In an ammonia combustion facility for burning ammonia mixed with air, a guide pipe is provided on the outer periphery of the tip of the ammonia discharge pipe that discharges the ammonia, for guiding the ammonia discharged from the ammonia discharge pipe into a furnace; air is introduced into the guide pipe through an air inlet section between the ammonia discharge pipe and the guide pipe; and the ammonia and air are jetted radially into the furnace from a plurality of radial jets provided radially on the outer periphery of the tip of the guide pipe to combust the ammonia, wherein the air ratio for burning the ammonia is set in the range of 0.95 to 0.99, and air introduction adjustment means is provided for adjusting the size of the air introduction section between the ammonia discharge pipe and the guide pipe.

2. An ammonia combustion facility as described in claim 1, characterized in that an air guide section for guiding air into a furnace is provided on the outer periphery of the guide tube, and the air guided into the furnace through the air guide section is mixed with the ammonia and air that is jetted radially into the furnace from a plurality of radial jets provided on the outer periphery of the tip of the guide tube along the inner wall surface of the furnace, and combusted, with an air ratio for burning ammonia in the range of 0.95 to 0.

99.

3. An ammonia combustion equipment as described in claim 2, characterized in that it is provided with a guide air adjustment means for adjusting the amount of air guided into the furnace through the air guide section.

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