Ammonia injection nozzle for combustor

Abstract

An ammonia injection nozzle for a combustor according to the present invention comprises: an ammonia pipe through which ammonia is transferred from the inside thereof; an injection hole installation unit which closes the front end of the ammonia pipe; at least two ammonia injection holes which are provided along the circumferential direction of the injection hole installation unit so as to allow the ammonia to be injected to the outside of the ammonia pipe; and an ammonia guide unit which is provided at the front end of the injection hole installation unit and has an outer diameter larger than the minimum diameter of the injection hole installation unit.

Description

Ammonia injection nozzle for combustor

[0001] The present invention relates to an ammonia injection nozzle for a combustor for supplying ammonia fuel to the inside of various combustors.

[0002] Fossil fuels are used in combustors for power generation, internal combustion engines for vehicles, ships, and aircraft, steelmaking, heating, and various other purposes. However, fossil fuels have the disadvantage of producing large amounts of environmental pollutants, such as carbon dioxide. Furthermore, fossil fuel reserves are gradually depleting, necessitating the urgent acquisition of alternative fuels.

[0003] In this regard, Korean Patent Publication No. 10-2023-0151387 discloses a circulating fluidized bed boiler capable of ammonia co-firing. According to this prior art, co-firing ammonia fuel minimizes the generation of environmental pollutants derived from fossil fuels. Furthermore, ammonia is relatively readily available, significantly reducing fossil fuel consumption.

[0004] Meanwhile, nitrogen oxides (NOx), an environmental pollutant, may be generated inside an operating combustor due to various factors such as incomplete combustion.

[0005] As part of solving the above-described problem, the present invention aims to provide an ammonia injection nozzle for a combustor capable of reducing nitrogen oxide (NOx) emissions caused by ammonia fuel.

[0006] An ammonia injection nozzle for a combustion chamber according to the present invention is characterized by including an ammonia pipe through which ammonia is transported from the inside, an injection hole installation part that closes the front end of the ammonia pipe, at least two ammonia injection holes provided along the circumferential direction of the injection hole installation part so that the ammonia is injected to the outside of the ammonia pipe, and an ammonia guide part provided at the front end of the injection hole installation part and having an outer diameter larger than the minimum diameter of the injection hole installation part.

[0007] In addition, the injection hole installation part is characterized in that it has a shape with a decreasing diameter, and the ammonia injection hole is provided coaxially with the thickness direction of the injection hole installation part.

[0008] In addition, the taper angle between the outer slope of the injection hole installation portion and the long axis of the ammonia pipe is 30° to 60°, and the injection angle between the long axis of the ammonia injection hole and the long axis of the ammonia pipe corresponds to a value obtained by subtracting the taper angle from a right angle.

[0009] In addition, it is characterized by including a connecting part having a concave outer shape between the outer surface of the injection hole installation part and the outer surface of the ammonia guide part.

[0010] In addition, it is characterized in that the edge extension of the ammonia injection hole and the rear edge of the ammonia guide part are spaced apart from each other by a predetermined distance.

[0011] In addition, it is characterized by including an ammonia pipe accommodated inside, a main air outlet formed in the front, and an air exhaust pipe for exhausting air.

[0012] In addition, it is characterized by including a plurality of auxiliary air injection holes formed along the circumference of the air discharge pipe.

[0013] In addition, the ammonia injection hole is characterized in that it is spaced in front of the main air outlet.

[0014] According to the ammonia injection nozzle for a combustor according to the present invention, a portion of the ammonia injected from the nozzle is recirculated back to the front side of the nozzle. Accordingly, the formation of a dead zone in which ammonia is incompletely combusted is prevented at the front side of the nozzle. Accordingly, ammonia is uniformly combusted inside the combustor, thereby minimizing nitrogen oxide emissions due to incomplete combustion, etc.

[0015] Additionally, the ammonia discharged by the air emitted from the air injector can be more uniformly distributed inside the combustor.

[0016] Additionally, a number of auxiliary air injection holes are formed on the outer surface of the air injection unit. Accordingly, air discharged from the auxiliary air injection holes forms an air curtain around the air injection unit. The cooling effect of the air curtain prevents thermal damage to the air injection unit as much as possible.

[0017] Additionally, a high-temperature combustion zone is created around the air curtain. This high temperature allows nitrogen oxides to react with ammonia and be reduced to nitrogen. Therefore, through the aforementioned reduction process, the final nitrogen oxide emissions are further reduced.

[0018] FIG. 1 is a drawing showing one embodiment of an ammonia injection nozzle for a combustor according to the present invention.

[0019] Figure 2 is a drawing showing the ammonia injection nozzle illustrated in Figure 1.

[0020] Figure 3 is an enlarged view of the “3” portion shown in Figure 2.

[0021] Figure 4 is a cross-sectional side view of Figure 2.

[0022] Figure 5 is an enlarged view of the “5” portion shown in Figure 4.

[0023] Figure 6 is a side view showing an ammonia injection unit according to Comparative Example 1.

[0024] Figure 7 shows the results of computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 1.

[0025] Figure 8 is a result of computational fluid dynamics analysis of an ammonia injection nozzle according to Example 1 of the present invention.

[0026] Figure 9 is a result of computational fluid dynamics analysis of an ammonia injection nozzle according to Example 2-1 of the present invention.

[0027] Figure 10 is a result of computational fluid dynamics analysis of an ammonia injection nozzle according to Example 2-2 of the present invention.

[0028] Figure 11 is a graph showing the nitrogen oxide production results of an ammonia injection nozzle according to Example 1, Example 2-1, and Example 2-2 of the present invention.

[0029] Figure 12 is a cross-sectional view showing an ammonia injection unit according to Comparative Example 3.

[0030] Fig. 13 is a side cross-sectional view showing an ammonia injection unit according to Example 3 of the present invention.

[0031] Figure 14 shows the results of computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 3.

[0032] Figure 15 is a result of computational fluid dynamics analysis of an ammonia injection nozzle according to Example 3 of the present invention.

[0033] Figure 16 is a graph showing the nitrogen oxide production results of an ammonia injection nozzle according to Comparative Example 3, Examples 1 and 3 of the present invention.

[0034] Figure 17 shows the results of computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 4.

[0035] Before proceeding with a detailed description of the present invention, specific details for implementing the present invention are included in the following examples and drawings. Furthermore, like reference numerals used throughout the specification denote like elements. Furthermore, singular expressions in this specification also include plural forms, unless specifically stated otherwise.

[0036] Hereinafter, an ammonia injection nozzle for a combustor according to the present invention will be described with reference to the drawings.

[0037] FIG. 1 is a drawing showing one embodiment of an ammonia injection nozzle for a combustor according to the present invention.

[0038] Referring to Fig. 1, an ammonia injection nozzle (1000) for a combustor according to the present invention can be installed in a combustor (10). In addition, the injection nozzle (1000) injects ammonia, which is an environmentally friendly fuel, into the inside of the combustor (10). In addition, if necessary, a plurality of injection nozzles (1000) can be provided at the main inlet of the combustor (10). In addition, if necessary, a plurality of injection nozzles (1000) can be provided along the longitudinal direction of the combustor (10).

[0039] Here, the above combustor (10) can be used for power generation, internal combustion engines for vehicles / ships / aircraft, steelmaking, heating, and various other purposes.

[0040] Next, Fig. 2 is a drawing showing the ammonia injection nozzle illustrated in Fig. 1. And, Fig. 3 is an enlarged view of the "3" portion illustrated in Fig. 2. And, Fig. 4 is a side cross-sectional view of Fig. 2. And, Fig. 5 is an enlarged view of the "5" portion illustrated in Fig. 4.

[0041] Referring further to FIGS. 2 to 5, the injection nozzle (1000) includes an ammonia injection unit (100) and an air injection unit (200).

[0042] The ammonia injection unit (100) is used for the purpose of supplying ammonia as fuel. In addition, the ammonia injection unit (100) can be connected to a separate ammonia supply source (not shown). In addition, the ammonia injection unit (100) includes an ammonia pipe (110), an injection hole installation unit (120), an ammonia injection hole (130), an ammonia guide unit (140), and a connection unit (150).

[0043] The ammonia pipe (110) above has a hollow pipe structure on the inside. Inside the ammonia pipe (110), ammonia is transported from the rear end toward the front end. A separate ammonia supply source (not shown) may be connected to the rear end of the ammonia pipe (110).

[0044] In addition, the injection hole installation part (120) closes the front end of the ammonia pipe (110). In addition, the injection hole installation part (120) may have a shape in which the diameter linearly decreases toward the front end. That is, the outer shape of the injection hole installation part (120) may have a kind of conical structure.

[0045] In addition, preferably, the taper angle (a) measured between the long axis of the ammonia pipe (110) and the outer slope of the injection hole installation portion (120) may be 30° to 60°. More preferably, the taper angle (a) may be 40°.

[0046] In addition, the ammonia injection holes (130) are provided in multiple numbers along the circumferential direction of the injection hole installation part (120). In addition, the ammonia injection holes (130) connect the inside and outside of the ammonia pipe (110). Accordingly, the ammonia inside the ammonia pipe (110) passes through the ammonia injection holes (130) and is supplied to the outside.

[0047] Here, the major axis of the ammonia injection hole (130) may be provided coaxially with the thickness direction of the injection hole installation part (120). In this case, the injection angle (b) between the major axis of the ammonia injection hole (130) and the major axis of the ammonia pipe (110) corresponds to a value obtained by subtracting the taper angle (a) from a right angle. Therefore, the preferable injection angle (b) may be 60° to 30°. More preferably, the injection angle (b) may be 50°.

[0048] In addition, the shortest distance between the edge extension of the ammonia injection hole (130) and the rear edge of the ammonia guide part (140) may be defined as a threshold gap (L). Here, when the rear edge of the ammonia guide part (140) and the edge extension of the ammonia injection hole (130) are in contact, the threshold gap (L) value may be defined as 0. In addition, when the rear edge of the ammonia guide part (140) encroaches on the inner area of ​​the edge extension of the ammonia injection hole (130), the threshold gap (L) value may be defined as a negative number.

[0049] If the threshold gap (L) is too narrow or has a value less than 0, the injected ammonia air stream may collide with the ammonia guide part (140). As a result, the ammonia air stream colliding with the ammonia guide part (140) may be dispersed toward the outer rear of the ammonia pipe (110). In other words, a significant amount of the ammonia air stream may be dispersed toward the inlet end of the combustor (10) rather than toward the outlet end of the combustor (10).

[0050] Alternatively, if the threshold gap (L) is excessively wide, it is difficult to add an appropriate curve / vortex to the ammonia airflow sprayed forward, making it difficult for ammonia to be recirculated toward the front side of the ammonia guide section (140). As a result, an incomplete combustion section that induces the production of nitrogen oxides (NOx) may be formed toward the front side of the ammonia guide section (140).

[0051] Therefore, the preferable threshold gap (L) may be 0.5 to 3 mm. Preferably, the threshold gap (L) may be 1 mm.

[0052] In addition, the ammonia guide part (140) is provided at the front end of the injection hole installation part (120). In addition, at least a portion of the outer shape of the ammonia guide part (140) may have a cylindrical structure.

[0053] In addition, preferably, the ammonia guide part (140) may have an outer diameter larger than the minimum diameter of the injection hole installation part (120). More preferably, the outer diameter of the ammonia guide part (140) may correspond to the outer diameter of the ammonia pipe (110).

[0054] In addition, the above-mentioned connecting portion (150) is defined between the injection hole installation portion (120) and the ammonia guide portion (140). In addition, the connecting portion (150) is continuously provided along the circumferential direction of the ammonia pipe (110). On the outside of the connecting portion (150), the space between the injection hole installation portion (120) and the ammonia guide portion (140) can be defined as an airflow disturbance area (E).

[0055] In addition, preferably, the connecting portion (150) may have a concave outer shape between the outer surface of the injection hole installation portion (120) and the outer surface of the ammonia guide portion (140). Therefore, between the outer surface of the injection hole installation portion (120) and the ammonia guide portion (140), the minimum outer diameter portion of the connecting portion (150) has the greatest depth. The curvature of the connecting portion (150) may be set to various numerical ranges and numbers.

[0056] In addition, the air injection unit (200) injects air. Here, the air may have various purposes, such as promoting combustion, smoothly guiding ammonia air flow, and the like. In addition, the air injection unit (200) includes an air discharge pipe (210), a main air outlet (211), and an auxiliary air injection hole (220).

[0057] The above air exhaust pipe (210) is formed with an internal hollow tube structure. Inside the air exhaust pipe (210), air flows from the rear toward the front. The rear end of the air exhaust pipe (210) may be connected to a separate air supply source (not shown).

[0058] Here, an ammonia pipe (110) is accommodated inside the air discharge pipe (210). That is, the air discharge pipe (210) and the ammonia pipe (110) can form a kind of double pipe structure.

[0059] In addition, the main air outlet (211) opens forward of the air discharge pipe (210). Accordingly, at least a portion of the air inside the air discharge pipe (210) is supplied to the outside through the main air outlet (211). Here, preferably, the ammonia injection holes (130) can be spaced forward from the main air outlet (211).

[0060] In addition, the auxiliary air injection holes (220) are provided in multiple numbers along the circumference of the air discharge pipe. Accordingly, the remaining portion of the air flowing inside the air discharge pipe (210) passes through the auxiliary air injection holes (220) and flows out to the outside.

[0061] [Example 1]

[0062] In response to the preferred examples described above, a spray nozzle (1000) according to the present embodiment was prepared. Key figures related to the present embodiment are as shown in [Table 1] below.

[0063] Classification details: Taper angle (a) 40°, Injection angle (b) 50°, Threshold gap (L) 1 mm

[0064] In addition, preferred examples related to the air injection unit (200) as shown in Fig. 3 were also applied to this embodiment.

[0065] [Comparative Example 1]

[0066] Figure 6 is a side view showing an ammonia injection unit according to Comparative Example 1.

[0067] Referring to FIG. 6 and FIG. 5, the ammonia injection unit (100) according to this comparative example compared to Example 1 did not include the injection hole installation unit (120), the ammonia guide unit (140), and the connection unit (150).

[0068] Additionally, in this comparative example, the ammonia injection hole (130) was provided along the front circumference of the ammonia pipe (110). The angle between the long axis of the ammonia injection hole (130) and the long axis of the ammonia pipe (110) was set to a right angle. At this time, the front end of the ammonia pipe (110) is closed.

[0069] Other than that, the remaining details of this comparative example are the same as Example 1.

[0070] [Example 1]

[0071] Figure 7 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 1. And, Figure 8 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Example 1 of the present invention.

[0072] Referring further to FIGS. 7 and 8, computational fluid dynamics analysis tests were performed for Example 1 and Comparative Example 1 based on the operating environment of the combustor (10).

[0073] As a result of the test, according to Comparative Example 1, it was confirmed that the combustion temperature at the front side of the ammonia injection unit (100) was significantly lower than that at other areas. That is, it was confirmed that a large-area dead zone (D1) where combustion was not smooth was formed at the front side of the ammonia injection unit (100) compared to the outlet end of the combustor (10).

[0074] According to Comparative Example 1, ammonia is difficult to inject forward of the ammonia pipe (110) and is injected at a right angle from the ammonia pipe (110). As a result, it is analyzed that ammonia is not smoothly supplied forward of the ammonia pipe (110), resulting in the formation of the large-area dead zone (D1). The above-described large-area dead zone (D1) causes incomplete combustion, etc., and generates a significant amount of environmental pollutants such as nitrogen oxides (NOx).

[0075] On the other hand, according to Example 1, it was confirmed that a high combustion temperature was formed at the front side of the combustor (10) compared to the rear side of the combustor (10).

[0076] That is, according to Example 1, ammonia is injected obliquely forward in response to the injection angle (b). In addition, due to the unique curved structure of the airflow disturbance area (E), at least a portion of the injected ammonia is recirculated back toward the ammonia pipe (110). In this way, according to Example 1, it is analyzed that sufficient ammonia is supplied to the front of the ammonia pipe (110), thereby minimizing the dead zone.

[0077] [Example 2-1]

[0078] The injection nozzle (1000) according to this embodiment was manufactured in the same manner as in Example 1. However, in this embodiment, the injection angle (b) and taper angle (a) were set to 40° and 50°.

[0079] [Example 2-2]

[0080] The injection nozzle (1000) according to this embodiment was manufactured in the same manner as in Example 1. However, in this embodiment, the injection angle (b) and taper angle (a) were set to 70° and 20°.

[0081] [Example 2-1]

[0082] Fig. 9 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Example 2-1 of the present invention. And, Fig. 10 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Example 2-2 of the present invention. And, Fig. 11 is a graph showing the results of nitrogen oxide production of an ammonia injection nozzle according to Examples 1, 2-1, and 2-2 of the present invention.

[0083] Comparing FIG. 8 and FIG. 9, it was confirmed that in Example 2-1 compared to Example 1, a ring-shaped dead zone (D2) having a kind of ring shape was formed on the front side of the ammonia pipe (110). That is, according to Example 2-1, it is analyzed that ammonia is recirculated in an excessively narrow area on the front side of the ammonia.

[0084] And, referring to Fig. 8 and Fig. 10, it was confirmed that the combustion temperature was extremely low in most areas in Example 2-2 compared to Example 1. That is, according to Example 2-2, the flame is excessively dispersed toward the wall surface of the combustor (10), and it is analyzed that this excessively increases the amount of incomplete combustion and nitrogen oxide production.

[0085] Therefore, referring to Fig. 11, it is confirmed that Example 1 is the best in terms of effective ammonia combustion and nitrogen oxide reduction.

[0086] [Comparative Example 3]

[0087] Figure 12 is a cross-sectional view showing an ammonia injection unit according to Comparative Example 3.

[0088] Referring further to Fig. 12, the injection nozzle (1000) according to this comparative example was manufactured in the same manner as in Example 1. However, in this example, the ammonia guide portion (140) and the connection portion (150) were not applied. In addition, the injection hole installation portion (120) of this example has a length that extends forward more than that of Example 1.

[0089] [Example 3]

[0090] Fig. 13 is a side cross-sectional view showing an ammonia injection unit according to Example 3 of the present invention.

[0091] Referring further to Fig. 13, the injection nozzle (1000) according to this comparative example was manufactured in the same manner as Example 1. However, in this example, the outer diameter of the connecting portion (150) increases linearly as it approaches the ammonia guide portion (140).

[0092] [Example 3]

[0093] Fig. 14 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 3. And, Fig. 15 shows the results of a computational fluid dynamics analysis of an ammonia injection nozzle according to Example 3 of the present invention. And, Fig. 16 is a graph showing the results of nitrogen oxide production of an ammonia injection nozzle according to Comparative Example 3 and Examples 1 and 3 of the present invention.

[0094] Comparing Fig. 8 and Fig. 14, it was confirmed that the combustion temperature in Comparative Example 3 was extremely low in most areas compared to Example 1. That is, according to Comparative Example 3, it was analyzed that ammonia was not smoothly distributed toward the front side of the ammonia pipe (110) due to the absence of the ammonia guide part (140).

[0095] And, comparing Fig. 8 and Fig. 15, it was confirmed that the combustion temperature in most areas was extremely low in Example 3 compared to Example 1. That is, according to Example 3, if the connecting portion (150) does not have sufficient curvature, the area of ​​the airflow disturbance area (E) becomes excessively narrow. As a result, it is analyzed that the airflow disturbance area (E) cannot appropriately change the direction of the ammonia airflow, resulting in the results as shown in Fig. 15.

[0096] Therefore, it was analyzed that the ammonia recirculation effect toward the front of the ammonia pipe (110) occurs only when both the ammonia guide part (140) and the curved connection part (150) are combined.

[0097] [Comparative Example 4]

[0098] The injection nozzle (1000) according to this comparative example was manufactured in the same manner as Example 1. However, in this example, the auxiliary air injection hole (220) was not applied.

[0099] [Example 4]

[0100] Figure 17 shows the results of computational fluid dynamics analysis of an ammonia injection nozzle according to Comparative Example 4.

[0101] Comparing Fig. 8 and Fig. 17, it was confirmed that in Example 4, compared to Example 1, the high-temperature airflow was concentrated only on the front side of the ammonia pipe (110). In addition, it was confirmed that ammonia combustion was not performed smoothly overall on the inside of the combustor (10). This means that it is difficult for the ammonia airflow to be evenly distributed by the air on the inside of the combustor (10).

[0102] On the other hand, according to Example 1, it was confirmed that combustion at an appropriate temperature was actively performed throughout the entire combustor (10) as previously discussed.

[0103] In particular, it was confirmed that a relatively low-temperature air curtain (C) was formed on the peripheral surface of the air injection unit (200). The air curtain (C) performs the function of protecting the air injection unit (200) from high temperatures.

[0104] Furthermore, it was confirmed that the highest combustion temperature was formed on the outside of the air curtain (C). Accordingly, outside the air curtain (C), nitrogen oxides react with ammonia via the high temperature and are ultimately reduced to nitrogen. Therefore, according to Example 1, it is analyzed that the nitrogen oxide reduction effect through the reduction action is further enhanced.

[0105] As described above, the present invention primarily aims to provide an ammonia injection nozzle for a combustor. Furthermore, the embodiments described above with reference to the drawings are merely exemplary, and the scope of the present invention should be determined based on the claims. Furthermore, the scope of the present invention extends to various equivalent embodiments that may be derived therefrom.

Claims

1. Ammonia pipe through which ammonia is transported from the inside; A spray hole installation part that closes the front end of the above ammonia pipe; At least two ammonia injection holes are provided along the circumference of the injection hole installation portion so that the ammonia is injected to the outside of the ammonia pipe; and An ammonia injection nozzle for a combustor, characterized in that it includes an ammonia guide part provided at the front end of the injection hole installation part and having an outer diameter larger than the minimum diameter of the injection hole installation part.

2. In paragraph 1, The above injection hole installation part is, It has a shape with decreasing diameter, The above ammonia injection hole is, An ammonia injection nozzle for a combustion chamber, characterized in that it is provided coaxially with the thickness direction of the above injection hole installation portion.

3. In paragraph 2, The taper angle between the outer slope of the above injection hole installation part and the long axis of the ammonia pipe is 30° to 60°, An ammonia injection nozzle for a combustor, characterized in that the injection angle between the long axis of the ammonia injection hole and the long axis of the ammonia pipe corresponds to a value obtained by subtracting the taper angle from a right angle.

4. In paragraph 3, An ammonia injection nozzle for a combustion chamber, characterized in that it includes a connecting portion having a concave outer shape between the outer surface of the injection hole installation portion and the outer surface of the ammonia guide.

5. In paragraph 4, An ammonia injection nozzle for a combustion chamber, characterized in that the edge extension of the ammonia injection hole and the rear edge of the ammonia guide part are spaced apart from each other by a predetermined distance.

6. In paragraph 1, An ammonia injection nozzle for a combustor, characterized in that it houses the ammonia pipe inside, has a main air outlet formed at the front, and includes an air discharge pipe for discharging air.

7. In paragraph 6, An ammonia injection nozzle for a combustion chamber, characterized in that it includes a plurality of auxiliary air injection holes formed along the circumference of the air discharge pipe.

8. In paragraph 7, The above ammonia injection hole is, An ammonia injection nozzle for a combustion chamber, characterized in that it is spaced forward of the main air outlet.

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