Combustion device

Abstract

To provide a combustion device that can enhance combustibility of low-grade fuel and can be attached to a furnace wall relatively easily.SOLUTION: A combustion device 1 has: a main fuel feed pipe 2 for feeding main fuel MF; a main fuel injection nozzle 3 for injecting the main fuel MF; an air feed pipe 4 for feeding primary combustion air A1; a primary combustion pipe 5 for primarily combusting mixed gas MG of the main fuel MF and the primary combustion air A1; and an auxiliary burner 6. The auxiliary burner 6 comprises: an auxiliary fuel feed pipe 61 for feeding auxiliary fuel SF; and an auxiliary fuel injection nozzle 62 for injecting the auxiliary fuel SF. In the combustion device 1, the auxiliary fuel feed pipe 61 of the auxiliary burner 6 is provided inside the main fuel feed pipe 2 and the main fuel injection nozzle 3. The auxiliary fuel injection nozzle 62 of the auxiliary burner 6 is provided projectingly toward the front part of the main fuel injection nozzle 3 from a front end of the main fuel injection nozzle 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a combustion device. [Background technology]

[0002] Conventionally, fuels known for use in combustion devices include ammonia, biomass-derived off-gas, by-product gas, and other fuels that have low calorific value and combustion speed and are poor in combustibility compared to hydrocarbon fuels (hereinafter sometimes referred to as "low-grade fuels"). In particular, ammonia has attracted attention as a fuel that does not emit carbon dioxide.

[0003] Prior Patent Document 1 discloses a combustion device in which ammonia is mixed with combustion air and burned in a furnace by a burner.

[0004] Specifically, the combustion device disclosed in Patent Document 1 mixes ammonia gas supplied through an ammonia supply pipe with combustion air supplied through an air supply pipe by a combustion burner and burns the mixture in a furnace. In this combustion device, an injection device to which a hydrocarbon-based fuel is supplied through an auxiliary fuel supply pipe is provided near the combustion burner, and the hydrocarbon-based fuel is injected into the furnace by the injection device toward the flame generated by the combustion burner to be burned. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-39683 A Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of Patent Document 1 supplies a hydrocarbon fuel to the furnace in addition to a low-grade fuel such as ammonia, so that the low-grade fuel can be sufficiently combusted in the furnace by the hydrocarbon fuel. However, even if the technology of Patent Document 1 can increase the combustibility of the low-grade fuel, it is necessary to attach an injection device to the furnace wall outside the combustion burner when supplying the hydrocarbon fuel to the furnace. Therefore, the technology of Patent Document 1 may make it complicated to attach the combustion device to the furnace wall.

[0007] The present invention has been made in consideration of the above problems, and aims to provide a combustion device that can improve the combustibility of low-grade fuel and can be relatively easily attached to a furnace wall. [Means for solving the problem]

[0008] One aspect of the present invention is a main fuel supply pipe for supplying a main fuel; a tubular main fuel ejection nozzle connected to the main fuel supply pipe for ejecting the main fuel; an air supply pipe provided on an outer periphery of the main fuel supply pipe and the main fuel ejection nozzle for supplying primary combustion air; a primary combustion tube connected to the air supply pipe for primarily combusting a mixed gas produced by mixing the main fuel ejected from the main fuel ejection nozzle and the primary combustion air supplied from the air supply pipe within the tube; an auxiliary burner unit including an auxiliary fuel supply pipe for supplying auxiliary fuel, and a tubular auxiliary fuel ejection nozzle connected to the auxiliary fuel supply pipe for ejecting the auxiliary fuel, the auxiliary fuel supply pipe of the auxiliary burner unit is provided inside the main fuel supply pipe and the main fuel ejection nozzle, The auxiliary fuel ejection nozzle of the auxiliary burner unit is provided to protrude forward from a front end portion of the main fuel ejection nozzle. Located in the combustion device. Effect of the Invention

[0009] The combustion device has the above-mentioned configuration, and therefore, according to the combustion device, it is possible to provide a combustion device that can enhance the combustibility of low-grade fuel and can be relatively easily attached to a furnace wall. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of a part of a main portion of a combustion device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the combustion device according to the present invention is as follows.

[0012] [1] a main fuel supply pipe for supplying a main fuel; a tubular main fuel ejection nozzle connected to the main fuel supply pipe for ejecting the main fuel; an air supply pipe provided on an outer periphery of the main fuel supply pipe and the main fuel ejection nozzle for supplying primary combustion air; a primary combustion tube connected to the air supply pipe for primarily combusting a mixed gas produced by mixing the main fuel ejected from the main fuel ejection nozzle and the primary combustion air supplied from the air supply pipe within the tube; an auxiliary burner unit including an auxiliary fuel supply pipe for supplying auxiliary fuel, and a tubular auxiliary fuel ejection nozzle connected to the auxiliary fuel supply pipe for ejecting the auxiliary fuel, the auxiliary fuel supply pipe of the auxiliary burner unit is provided inside the main fuel supply pipe and the main fuel ejection nozzle, The auxiliary fuel ejection nozzle of the auxiliary burner unit is provided to protrude forward from a front end portion of the main fuel ejection nozzle. Combustion device. [2] the main fuel includes ammonia; The auxiliary fuel is at least one selected from a hydrocarbon fuel, hydrogen, and ammonia cracked gas. [1] A combustion apparatus according to the present invention. [3] The auxiliary burner unit is a rod-shaped pipe burner or a rod-shaped surface combustion burner. A combustion apparatus according to [1] or [2]. [4] The main fuel ejection nozzle is a multi-flame hole nozzle, a metal knit nozzle, or a nozzle having a swirling function for swirling the main fuel. A combustion apparatus according to any one of [1] to [3]. [5] a secondary combustion tube for supplying secondary combustion air to the front of the primary combustion tube, the secondary combustion tube being disposed on the outer periphery of the air supply tube and the primary combustion tube; The space between the primary combustion tube and the secondary combustion tube is a flow path for the secondary combustion air. A combustion apparatus according to any one of [1] to [4]. [6] the main fuel includes ammonia; The secondary combustion tube is configured to be able to mix ammonia with the secondary combustion air. [5] A combustion apparatus according to the present invention. [7] an outer tube is provided around the secondary combustion tube for allowing the combustion exhaust gas generated by the combustion of the mixed gas to flow rearward; The space between the secondary combustion tube and the outer tube is a flow path for the combustion exhaust gas. A combustion apparatus according to [5] or [6].

[0013] The combustion device described in [1] above has the above configuration. Therefore, the combustion device described in [1] above can combust the main fuel in the following manner.

[0014] The main fuel supplied to the main fuel supply pipe flows through the main fuel supply pipe and is ejected from the main fuel ejection nozzle into the air supply pipe. Meanwhile, the primary combustion air supplied to the air supply pipe flows through the air supply pipe and mixes with the main fuel ejected from the main fuel ejection nozzle. The main fuel and the primary combustion air are mixed to generate a mixed gas. The auxiliary fuel supplied to the auxiliary fuel supply pipe of the auxiliary burner unit provided inside the main fuel supply pipe and the main fuel ejection nozzle flows through the auxiliary fuel supply pipe and is ejected from the auxiliary fuel ejection nozzle of the auxiliary burner unit provided protruding from the front end of the main fuel ejection nozzle into the primary combustion tube. The mixed gas flowing in the primary combustion tube gradually starts to burn while receiving a pilot flame due to combustion of the auxiliary fuel ejected from the auxiliary fuel ejection nozzle, and a flame due to primary combustion is formed in the primary combustion tube. The formed flame ejects from the front end of the primary combustion tube.

[0015] Therefore, according to the combustion device described in [1] above, even when a low-grade fuel such as ammonia, which has a low calorific value and combustion speed and is less combustible than a hydrocarbon fuel, is used as the main fuel, the combustibility of the low-grade fuel can be improved. Note that the combustion device described in [1] above can also use commonly used hydrocarbon fuels as the main fuel in addition to low-grade fuels.

[0016] In addition, in the combustion device described in [1] above, an auxiliary burner unit that supplies auxiliary fuel to the mixed gas is arranged inside the air supply pipe and primary combustion pipe necessary for the primary combustion of the mixed gas of the main fuel and primary combustion air. Therefore, according to the combustion device described in [1] above, it is not necessary to separately install an auxiliary burner on the furnace wall around the combustion device, and it is sufficient to simply install the combustion device on the furnace wall. Therefore, according to the combustion device described in [1] above, it is possible to relatively easily install it on the furnace wall.

[0017] Therefore, according to the combustion apparatus described in [1] above, it is possible to provide a combustion apparatus that can improve the combustibility of low-grade fuel and can be relatively easily attached to a furnace wall.

[0018] The combustion device described in [2] above has the above configuration. Therefore, according to the combustion device described in [2] above, the effects of the combustion device described in [1] above can be ensured.

[0019] The combustion device described in [3] above has the above configuration. Therefore, in the combustion device described in [3] above, when the auxiliary burner section is composed of a rod-shaped pipe burner, in addition to the effects described in [1] or [2] above, there is an additional effect that the suction effect of the discharge jet creates an entrainment recirculation flow, improving flame stability. Also, in the combustion device described in [3] above, when the auxiliary burner section is composed of a rod-shaped surface combustion burner, in addition to the effects described in [1] or [2] above, there is an additional effect that the flame stability of the pilot flame is easily ensured.

[0020] The combustion device described in [4] above has the above configuration. Therefore, in the combustion device described in [4] above, when the main fuel ejection nozzle is a multi-flame hole nozzle, in addition to the effects described in any one of [1] to [3] above, there is an effect that it is possible to improve combustibility by adjusting the injection position, such as by blocking or reducing the nozzle. In addition to the effects described in any one of [1] to [3] above, in the combustion device described in [4] above, when the main fuel ejection nozzle is a metal knit nozzle, in addition to the effects described in any one of [1] to [3] above, there is an effect that high-load combustion by surface combustion is possible. In addition to the effects described in any one of [1] to [3] above, in the combustion device described in [4] above, when the main fuel ejection nozzle is a nozzle equipped with a swirling function for swirling the main fuel, in addition to the effects described in any one of [1] to [3] above, there is an effect that the main fuel and the primary air go forward while swirling and mixing, so that the mixability of the mixed gas is improved and the residence time of the mixed gas is easily secured, and the combustibility of the main fuel can be further improved.

[0021] The combustion device described in [5] above has the above configuration. Therefore, according to the combustion device described in [5] above, the secondary combustion air supplied to the secondary combustion tube flows through a flow path formed between the primary combustion tubes and is supplied to the front of the primary combustion tube. Therefore, according to the combustion device described in [5] above, the flame formed in the primary combustion tube and ejected to the front of the primary combustion tube can receive the secondary combustion air in front of the primary combustion tube and further perform secondary combustion. In other words, according to the combustion device described in [5] above, after the main fuel is primarily combusted in the primary combustion tube, the insufficient air can be supplemented in front of the primary combustion tube to perform secondary combustion of the main fuel. Therefore, according to the combustion device described in [5] above, in addition to the effects described in any one of [1] to [4] above, it is possible to further reduce the NOx concentration in the combustion exhaust gas.

[0022] The combustion device described in [6] above has the above configuration. Therefore, according to the combustion device described in [6] above, in addition to the effect described in [5] above, the NOx concentration in the combustion exhaust gas can be further reduced by the denitrification effect of the ammonia mixed in the secondary combustion air.

[0023] The combustion device described in [7] above has the above configuration. Therefore, according to the combustion device described in [7] above, the combustion exhaust gas generated by the combustion of the mixed gas can be returned to the rear of the combustion device through a flow path formed between the secondary combustion tube and the outer tube. Therefore, according to the combustion device described in [7] above, in addition to the effects described in [5] or [6] above, the mixed gas and the secondary combustion gas can be preheated by heat exchange with the combustion exhaust gas. Therefore, according to the combustion device described in [7] above, the combustibility of the main fuel can be further improved.

[0024] When the combustion device described in [7] above is applied to, for example, a single-end type radiant tube burner, the front end of the secondary combustion tube in the combustion device is open, and the front end of the outer tube is closed. In this case, the combustion exhaust gas exhausted from the front end of the secondary combustion tube can be made to flow into the flow path between the secondary combustion tube and the outer tube at the front end of the outer tube, and returned to the rear of the combustion device. When the combustion device is applied to, for example, a direct heating burner, it can be used without removing the outer tube. In this case, the combustion exhaust gas exhausted from the front end of the secondary combustion tube can be exhausted outside the furnace by utilizing the furnace pressure.

[0025] Hereinafter, the combustion device of the embodiment will be described in more detail with reference to the drawings. In this embodiment, the direction in which flame is ejected from the combustion device 1 is the front, and the opposite direction is the rear.

[0026] As illustrated in Fig. 1, the combustion device 1 of this embodiment has at least a main fuel supply pipe 2, a main fuel ejection nozzle 3, an air supply pipe 4, a primary combustion tube 5, and an auxiliary burner unit 6. The combustion device 1 of this embodiment further has a secondary combustion tube 7 and an outer tube 8. In this embodiment, these members are provided coaxially with respect to a central axis 90 of the combustion device 1. Note that Fig. 1 shows an example in which the combustion device 1 of this embodiment is installed on a furnace wall 91 of a furnace via a device mounting member 92 equipped with a heat insulating material 920.

[0027] The main fuel supply pipe 2 is a pipe for supplying the main fuel MF. The main fuel supply pipe 2 is configured to be able to take in the main fuel MF into the pipe from a main fuel intake port 21 provided on the pipe peripheral wall at the rear end. In this embodiment, the main fuel MF may contain, for example, ammonia. Here, it is assumed that, for example, ammonia is used as the main fuel MF. Note that ammonia is one of the low-grade fuels, which has a small calorific value and combustion speed and is poorly combustible compared to hydrocarbon fuels. In addition to ammonia, other examples of the main fuel MF include off-gas and by-product gas derived from biomass.

[0028] The main fuel injection nozzle 3 is a tubular nozzle for injecting the main fuel MF. The main fuel injection nozzle 3 is connected to the main fuel supply pipe 2. Specifically, the rear end of the main fuel injection nozzle 3 is connected to the front end of the main fuel supply pipe 2. The outer diameter of the main fuel injection nozzle 3 is formed to be larger than the outer diameter of the main fuel supply pipe 2 excluding the attachment portion of the main fuel injection nozzle 3.

[0029] The main fuel ejection nozzle 3 has a number of flame holes 31 on the peripheral wall of the pipe, and is configured to be able to eject the main fuel MF in the radial direction. The front end face of the main fuel ejection nozzle 3 is closed. In this embodiment, the main fuel ejection nozzle 3 is a metal knit nozzle. In the metal knit nozzle, the surface of the peripheral wall having the number of flame holes 31 is covered with a metal knit 32. Although not shown, the main fuel ejection nozzle 3 may be a multi-flame hole nozzle having a number of flame holes on the peripheral wall of the pipe, or a nozzle equipped with a swirling function for swirling the main fuel MF. As a nozzle equipped with a swirling function for swirling the main fuel MF, for example, a nozzle having a spiral projection or groove for swirling the main fuel MF formed on the surface of the peripheral wall of the pipe on which a number of flame holes are formed can be exemplified.

[0030] The air supply pipe 4 is a pipe for supplying the primary combustion air A1. The air supply pipe 4 is provided on the outer periphery of the main fuel supply pipe 2 and the main fuel ejection nozzle 3. A passage for the primary combustion air A1 is provided between the main fuel supply pipe 2 and the main fuel ejection nozzle 3 and the air supply pipe 4. In this embodiment, the rear end of the main fuel supply pipe 2 is provided so as to protrude rearward from a rear end wall 41 that closes the rear end face of the air supply pipe 4.

[0031] The primary combustion tube 5 is a tube for primary combustion of the mixed gas MG generated by mixing the main fuel MF ejected from the main fuel ejection nozzle 3 and the primary combustion air A1 supplied from the air supply tube 4. The primary combustion tube 5 is connected to the air supply tube 4. Specifically, the rear end of the primary combustion tube 5 is connected to the front end of the air supply tube 4. The outer diameter of the primary combustion tube 5 is formed to be equal to the outer diameter of the air supply tube 4. In FIG. 1, an example is shown in which the front end of the air supply tube 4 is extended forward to simplify the structure, etc., so that the primary combustion tube 5 is configured. The front end opening 51 of the primary combustion tube 5 is disposed forward of the front end of the auxiliary burner section 6. In this embodiment, the space between the front end of the auxiliary burner section 6 and the front end opening 51 of the primary combustion tube 5, i.e., the area S1 circled in FIG. 1, is the main primary combustion space.

[0032] In the combustion device 1, a flame generated by the combustion of the mixed gas MG is ejected from a front end opening 51 of the primary combustion tube 5. Therefore, the main fuel supply pipe 2, the main fuel ejection nozzle 3, the air supply pipe 4, and the primary combustion tube 5 can be said to configure a primary combustion burner section.

[0033] The auxiliary burner section 6 includes an auxiliary fuel supply pipe 61 and an auxiliary fuel ejection nozzle 62. The auxiliary fuel supply pipe 61 is a pipe for supplying the auxiliary fuel SF. The auxiliary fuel supply pipe 61 is configured so that the auxiliary fuel SF can be taken into the pipe from the rear end opening. In this embodiment, the auxiliary fuel SF can be at least one selected from a hydrocarbon fuel, hydrogen, and ammonia decomposition gas. Examples of the hydrocarbon fuel include city gas and liquefied petroleum gas (LPG). Examples of the ammonia decomposition gas include gas generated when ammonia is decomposed by a catalyst. Here, for example, city gas, which is a hydrocarbon fuel, is used as the auxiliary fuel SF.

[0034] The auxiliary fuel ejection nozzle 62 is a tubular nozzle for ejecting the auxiliary fuel SF. The auxiliary fuel ejection nozzle 62 is connected to the auxiliary fuel supply pipe 61. Specifically, the rear end of the auxiliary fuel ejection nozzle 62 is connected to the front end of the auxiliary fuel supply pipe 61. The outer diameter of the auxiliary fuel ejection nozzle 62 is formed to be equal to the outer diameter of the auxiliary fuel supply pipe 61. That is, in FIG. 1, the front end of the auxiliary fuel supply pipe 61 is extended forward to form the auxiliary fuel ejection nozzle 62 for the purpose of simplifying the structure. The auxiliary fuel ejection nozzle 62 has a number of flame holes 621 formed in the peripheral wall of the pipe, and the surface of the peripheral wall having the number of flame holes 621 is covered with a metal knit 622. The front end face of the auxiliary fuel ejection nozzle 62 is closed, and the auxiliary fuel ejection nozzle 62 can eject the auxiliary fuel SF in the radial direction from the number of flame holes 621 in the peripheral wall of the pipe.

[0035] In this embodiment, the auxiliary burner section 6 can be said to be composed of a rod-shaped surface combustion burner. The auxiliary burner section 6 can be composed of a rod-shaped pipe burner other than the rod-shaped surface combustion burner. The rod-shaped pipe burner can be composed of, for example, one that does not include the metal knit 622 that covers the multiple flame holes 621 in the above. In other words, the rod-shaped surface combustion burner can be composed by covering the multiple flame holes 621 of the rod-shaped pipe burner with the metal knit 622.

[0036] In the auxiliary burner section 6, the auxiliary fuel supply pipe 61 is provided inside the main fuel supply pipe 2 and the main fuel ejection nozzle 3. The auxiliary fuel ejection nozzle 62 is provided protruding from the front end of the main fuel ejection nozzle 3 forward of the main fuel ejection nozzle 3. In FIG. 1, the auxiliary burner section 6 penetrates the front end face of the main fuel ejection nozzle 3, the auxiliary fuel ejection nozzle 62 is disposed forward of the front end face of the main fuel ejection nozzle 3, and the auxiliary fuel supply pipe 61 is disposed rearward of the front end face of the main fuel ejection nozzle 3. In the auxiliary burner section 6, the protruding length of the auxiliary fuel ejection nozzle 62 from the front end of the main fuel ejection nozzle 3 can be set to an appropriate length so as to make the flame surface longer and wider and to ensure a longer contact time with the mixed gas MG.

[0037] The secondary combustion tube 7 is a tube for supplying the secondary combustion air A2 to the front of the primary combustion tube 5. The secondary combustion tube 7 is provided on the outer periphery of the air supply tube 4 and the primary combustion tube 5. A passage for the secondary combustion air A2 is provided between the primary combustion tube 5 and the secondary combustion tube 7. The front end of the secondary combustion tube 7 is disposed forward of the front end opening 51 of the primary combustion tube 5. In this embodiment, the space in front of the front end opening 51 of the primary combustion tube 5, that is, the area S2 circled in FIG. 1, is the main secondary combustion space. The secondary combustion tube 7 has a front end opening (not shown) at its front end. That is, the front end of the secondary combustion tube 7 is open.

[0038] In this embodiment, the secondary combustion tube 7 can be configured to mix ammonia (not shown) with the secondary combustion air A2. In this embodiment, since the main fuel MF is ammonia, for example, a portion of the ammonia in the main fuel MF supplied to the main fuel supply pipe 2 can be supplied to the secondary combustion tube 7 to mix the ammonia with the secondary combustion air A2. In addition, ammonia from an ammonia source other than the ammonia in the main fuel MF supplied to the main fuel supply pipe 2 can also be configured to be mixed with the secondary combustion air A2.

[0039] The outer tube 8 is a tube for flowing the combustion exhaust gas EG generated by the combustion of the mixed gas MG backward. The outer tube 8 is provided on the outer periphery of the secondary combustion tube 7. A passage for the combustion exhaust gas EG is provided between the secondary combustion tube 7 and the outer tube 8. The front end of the outer tube 8 may be closed, or may have a front end opening (not shown) at the front end. Since this embodiment shows an example in which the combustion device 1 is applied to a single-end type radiant tube burner, the front end of the outer tube 8 is closed. In addition, the rear end of the outer tube 8 communicates with the above-mentioned device mounting member 92 provided on the furnace wall 91 of the furnace, and the combustion exhaust gas EG is exhausted from an exhaust gas port 921 formed in the device mounting member 92.

[0040] The combustion device 1 of this embodiment can combust the main fuel MF as follows: The mixed gas MG and the auxiliary fuel SF can be ignited by an ignition rod (not shown) or the like.

[0041] The main fuel MF supplied to the main fuel supply pipe 2 flows through the main fuel supply pipe 2 and is ejected from the main fuel ejection nozzle 3 into the air supply pipe 4. Meanwhile, the primary combustion air A1 supplied to the air supply pipe 4 flows through the air supply pipe 4 and mixes with the main fuel MF ejected from the main fuel ejection nozzle 3. A mixed gas MG is generated by mixing the main fuel MF and the primary combustion air A1. In addition, the auxiliary fuel SF supplied to the auxiliary fuel supply pipe 61 of the auxiliary burner unit 6 provided inside the main fuel supply pipe 2 and the main fuel ejection nozzle 3 flows through the auxiliary fuel supply pipe 61 and is ejected into the primary combustion tube 5 from the auxiliary fuel ejection nozzle 62 of the auxiliary burner unit 6 provided in the front end of the main fuel ejection nozzle 3 so as to protrude forward of the main fuel ejection nozzle 3. The mixed gas MG flowing inside the primary combustion tube 5 gradually starts to burn while receiving a pilot flame from the combustion of the auxiliary fuel SF ejected from the auxiliary fuel ejection nozzle 62, and a flame due to primary combustion is formed inside the primary combustion tube 5. The formed flame ejects from the front end of the primary combustion tube 5.

[0042] Therefore, according to the combustion device 1 of this embodiment, even when a low-grade fuel such as ammonia, which has a low calorific value and combustion speed and is less combustible than hydrocarbon fuels, is used as the main fuel MF, the combustibility of the low-grade fuel can be improved.

[0043] In addition, in the combustion apparatus 1 of this embodiment, an auxiliary burner section 6 that supplies auxiliary fuel SF to the mixed gas MG of the main fuel MF and primary combustion air A1 is disposed inside the air supply pipe 4 and primary combustion pipe 5 required for primary combustion of the mixed gas MG. Therefore, according to the combustion apparatus 1 of this embodiment, it is not necessary to separately attach an auxiliary burner to the furnace wall 91 around the combustion apparatus 1, and it is sufficient to simply attach the combustion apparatus 1 to the furnace wall 91. Therefore, according to the combustion apparatus 1 of this embodiment, it is possible to relatively easily attach it to the furnace wall 91.

[0044] Therefore, according to the combustion device 1 of this embodiment, the combustibility of the low-grade fuel can be improved, and the attachment to the furnace wall 91 can be made relatively simple.

[0045] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the configurations shown in the above-described embodiment can be arbitrarily combined with each other. Furthermore, the claims described in the claims at the time of filing can be arbitrarily combined with each other. [Explanation of symbols]

[0046] 1 Combustion equipment 2 Main fuel supply pipe 3 Main fuel ejection nozzle 4 Air supply pipe 5 Primary combustion tube 6 Auxiliary burner section 61 Auxiliary fuel supply pipe 62 Auxiliary fuel injection nozzle MF main fuel SF auxiliary fuel A1 Primary combustion air MG mixed gas

Claims

1. a main fuel supply pipe for supplying a main fuel; a tubular main fuel ejection nozzle connected to the main fuel supply pipe for ejecting the main fuel; an air supply pipe provided around the outer periphery of the main fuel supply pipe and the main fuel ejection nozzle, for supplying primary combustion air; a primary combustion tube connected to the air supply pipe for primarily combusting a mixed gas produced by mixing the main fuel ejected from the main fuel ejection nozzle and the primary combustion air supplied from the air supply pipe within the tube; an auxiliary burner unit including an auxiliary fuel supply pipe for supplying auxiliary fuel, and a tubular auxiliary fuel ejection nozzle connected to the auxiliary fuel supply pipe for ejecting the auxiliary fuel, the auxiliary fuel supply pipe of the auxiliary burner unit is provided inside the main fuel supply pipe and the main fuel ejection nozzle, The auxiliary fuel ejection nozzle of the auxiliary burner unit is provided to protrude forward from a front end portion of the main fuel ejection nozzle. Combustion device.

2. the main fuel includes ammonia; The auxiliary fuel is at least one selected from a hydrocarbon fuel, hydrogen, and an ammonia cracked gas. The combustion device of claim 1 .

3. The auxiliary burner unit is composed of a rod-shaped pipe burner or a rod-shaped surface combustion burner. The combustion device according to claim 1 or 2.

4. The main fuel ejection nozzle is a multi-flame hole nozzle, a metal knit nozzle, or a nozzle having a swirling function for swirling the main fuel. The combustion device according to claim 1 or 2.

5. a secondary combustion tube for supplying secondary combustion air to the front of the primary combustion tube, the secondary combustion tube being disposed on the outer periphery of the air supply tube and the primary combustion tube; The space between the primary combustion tube and the secondary combustion tube is a flow path for the secondary combustion air. The combustion device according to claim 1 or 2.

6. the main fuel includes ammonia; The secondary combustion tube is configured to be able to mix ammonia with the secondary combustion air. The combustion device according to claim 5.

7. an outer tube is provided around the secondary combustion tube for allowing the combustion exhaust gas generated by the combustion of the mixed gas to flow rearward; The space between the secondary combustion tube and the outer tube is a flow path for the combustion exhaust gas. The combustion device according to claim 5.

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