Regenerative heat combustion equipment

Abstract

To prevent CO, CO2 and NOx or the like from being discharged while being contained in a combustion exhaust gas after the combustion of a fuel gas, in heat accumulation type combustion equipment having paired heat accumulation type combustion burners which alternately perform a combustion operation and a heat accumulation operation.SOLUTION: In heat accumulation type combustion equipment having paired heat accumulation type combustion burners 10a, 10b which alternately perform a combustion operation and a heat accumulation operation, the heat accumulation type combustion burner 10a for performing the combustion operation supplies a hydrogen gas H2 and a combustion support gas Gs of a fuel gas to a fuel injection nozzle 11a, heats combustion air Air introduced into a heat accumulation part 20a in which a heat accumulation body x is accommodated by adding a dilution gas Gi thereto, injects the hydrogen gas H2 and the combustion support gas of the fuel gas from the fuel injection nozzle into a furnace 1, and injects the heated combustion air and the dilution gas into the furnace from a supply / discharge port 24a of the heat accumulation type combustion burner 10a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a regenerative combustion facility equipped with a pair of regenerative combustion burners, which alternately performs a combustion operation in which combustion air heated through a thermal storage unit containing a thermal storage body is ejected from an intake and exhaust port into a furnace, and fuel gas ejected from a fuel ejection nozzle is mixed with the combustion air to burn the fuel gas in the furnace, and a heat storage operation in which the supply of fuel from the fuel supply nozzle is stopped, and the combustion exhaust gas after the fuel gas is burned in the furnace is led from the intake and exhaust port to the thermal storage unit to store the heat of the combustion exhaust gas in the thermal storage unit contained in the thermal storage unit. In particular, the present invention is characterized in that the combustion exhaust gas after the combustion of the fuel gas is prevented from containing CO, CO2, NOx, etc. and being discharged, which would harm the environment. [Background technology]

[0002] Conventionally, in industrial furnaces for heat-treating various workpieces such as steel materials, in order to effectively utilize the heat of the combustion exhaust gas produced when fuel is burned in the furnace, as shown in Patent Documents 1, 2, etc., regenerative combustion equipment equipped with a pair of regenerative combustion burners has been widely used which alternately performs a combustion operation in which heated combustion air is ejected from an intake and exhaust port into the furnace through a heat storage section containing a heat storage body, and fuel gas ejected from a fuel ejection nozzle is mixed with the combustion air to burn the fuel gas in the furnace, and a heat storage operation in which the supply of fuel from the fuel supply nozzle is stopped, the combustion exhaust gas obtained after the fuel gas is burned in the furnace is guided from the intake and exhaust port to the heat storage section, and the heat of the combustion exhaust gas is stored in the heat storage section contained in the heat storage section.

[0003] In the above-mentioned regenerative heat combustion equipment, hydrocarbon gases such as city gas are generally widely used as the fuel gas.

[0004] However, when hydrocarbon gases such as city gas are mixed with combustion air and burned, CO, CO2, and other gases that are believed to cause global warming are generated, and there is a problem that such combustion exhaust gases can harm the environment if they are discharged as they are.

[0005] Furthermore, hydrogen gas (H2), which has high combustibility, has been known as a fuel gas that does not generate CO, CO2, etc.

[0006] However, when highly combustible hydrogen gas is used as the fuel gas for the regenerative combustion burner as described above and mixed with heated combustion air for combustion, the flame temperature during combustion becomes high, making it easier for large amounts of NOx to be generated. This creates the problem that exhausting such NOx-rich combustion exhaust gas as it is can also be harmful to the environment. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6545739 [Patent Document 2] Patent No. 4602858 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] The present invention aims to solve the above-mentioned problems in a regenerative combustion facility equipped with a pair of regenerative combustion burners which alternately perform a combustion operation in which combustion air heated through a heat storage section containing a heat storage body is ejected from an intake and exhaust port into the furnace, and fuel gas ejected from a fuel ejection nozzle is mixed with the combustion air to burn the fuel gas in the furnace, and a heat storage operation in which the supply of fuel from the fuel supply nozzle is stopped, and the combustion exhaust gas after the fuel gas has been burned in the furnace is guided from the intake and exhaust port to the heat storage section to store the heat of the combustion exhaust gas in the heat storage body contained in the heat storage section.

[0009] In other words, in the present invention, in a regenerative combustion equipment as described above, when hydrogen gas, which does not generate CO, CO2, etc. during combustion, is used as the fuel gas for the regenerative combustion burner and is mixed with heated combustion air and burned, the objective of the present invention is to suppress the generation of NOx due to an increase in flame temperature during combustion, thereby preventing the environment from being harmed by the combustion exhaust gas discharged from the regenerative combustion equipment. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the regenerative combustion equipment according to the present invention is provided with a pair of regenerative combustion burners that perform a combustion operation in which combustion air heated through a heat storage section containing a heat storage body is ejected from an intake and exhaust port into a furnace and fuel gas is ejected from a fuel ejection nozzle, and the fuel gas is mixed with the combustion air and burned, and a regenerative combustion burner that does not eject fuel gas from the fuel ejection nozzle and performs a heat storage operation in which the combustion exhaust gas after the fuel gas is burned is guided from inside the furnace through the intake and exhaust port to a heat storage body contained in the heat storage section, and the heat of the combustion exhaust gas is stored in the heat storage body, and the regenerative combustion equipment alternates between the combustion operation and the heat storage operation in the pair of regenerative combustion burners, The fuel gas used is hydrogen gas without using any hydrocarbon gas, In the regenerative combustion burner performing a combustion operation, a fuel gas using hydrogen gas and a combustion support gas are supplied to a fuel ejection nozzle, a dilution gas is added to the combustion air introduced into the heat storage unit containing the heat storage body, and the air is heated. The fuel gas using hydrogen gas and the combustion support gas are ejected from the fuel ejection nozzle into the furnace, and the heated combustion air and the dilution gas are ejected from the intake and exhaust port into the furnace. A part of the fuel gas using hydrogen gas is mixed with the oxidizing gas and combusted in the furnace as a primary combustion. Also, the combustion air with the dilution gas added and the oxygen concentration reduced is heated in the heat storage section and ejected into the furnace from the intake and exhaust port. The hydrogen gas of the fuel gas that was not combusted in the primary combustion is mixed with the combustion air with the oxygen concentration reduced to perform the secondary combustion. I made it so that.

[0011] And, as mentioned above Uses hydrogen gas as fuel gas, not hydrocarbon gas, In a regenerative combustion burner performing a combustion operation, when fuel gas using hydrogen gas and oxidizing gas are ejected from a fuel ejection nozzle into a furnace, a part of the fuel gas using hydrogen gas is mixed with the oxidizing gas and is primarily combusted in the furnace. Also, the combustion air with a low oxygen concentration due to the addition of dilution gas is mixed with the oxidizing gas and is then burned. ofIt is heated in the heat storage section and ejected into the furnace from the intake and exhaust port. height , Hydrogen gas, which is fuel gas that was not combusted first of As described above, the oxygen concentration of the combustion air is reduced. height Secondary combustion height Like Therefore, Conventionally, hydrogen gas as fuel gas is mixed with heated combustion air in a high oxygen concentration state. 、 This prevents the fuel from being burned suddenly all at once, and prevents the flame temperature during combustion from becoming too high, which can lead to the generation of NOx.

[0012] Here, in the regenerative combustion equipment of the present invention, when adding a dilution gas to the combustion air supplied to the regenerative combustion burner that performs the combustion operation as described above, an inert gas such as nitrogen gas N2 can be used as the dilution gas, and in the regenerative combustion burner that performs the heat storage operation, the combustion exhaust gas after storing heat in the heat storage material contained in the heat storage section can also be used as the dilution gas.

[0013] In addition, when supplying hydrogen gas as the fuel gas to the fuel injection nozzle, in addition to supplying the hydrogen gas itself to the fuel injection nozzle, it is also possible to supply hydrogen gas separated from ammonia gas NH3 by an ammonia reforming separation device to the fuel injection nozzle.

[0014] Furthermore, the gas containing nitrogen gas remaining after separating hydrogen gas from ammonia gas as described above can be used as the dilution gas and mixed with the combustion air. Effect of the Invention

[0015] In the regenerative combustion equipment of the present invention, when a pair of regenerative combustion burners alternately perform a combustion operation and a heat storage operation, Uses hydrogen gas as fuel gas, not hydrocarbon gas,In a regenerative combustion burner that performs combustion operation, fuel gas using hydrogen gas and combustion supporting gas are supplied to a fuel ejection nozzle, and dilution gas is added to the combustion air that is led to the heat storage section in which the heat storage body is housed to heat it, and the fuel gas using hydrogen gas and the combustion supporting gas are ejected from the fuel ejection nozzle into the furnace, and the heated combustion air and the dilution gas are ejected into the furnace from the intake and exhaust port.In this way, a portion of the hydrogen gas ejected from the fuel ejection nozzle is mixed with the combustion supporting gas and undergoes primary combustion in the furnace, and then the remaining hydrogen gas that was not subjected to primary combustion is mixed with the combustion air with a low oxygen concentration that has been heated in the heat storage section and ejected from the intake and exhaust port into the furnace to undergo secondary combustion.

[0016] As a result, in the regenerative combustion equipment of the present invention, the hydrogen gas fuel gas is not combusted all at once in a state where the combustion air and oxygen concentration are high, as in the conventional case, and the flame temperature during combustion is prevented from becoming too high.Even when highly combustible hydrogen gas that does not generate CO, CO2, etc. is used as the fuel gas for the regenerative combustion burner, it is possible to prevent NOx from being generated during combustion. [Brief description of the drawings]

[0017] [Figure 1] This is a schematic diagram showing a regenerative combustion equipment according to one embodiment of the present invention, and illustrates a state in which, in a regenerative combustion burner performing combustion operation, hydrogen gas of the fuel gas and combustion supporting gas are ejected from a fuel ejection nozzle into the furnace, and a portion of the hydrogen gas of the fuel gas is primarily combusted, while dilution gas is added to an air guide tube that leads the combustion air to a heat storage section in which a heat storage body is housed, and the combustion air with a lower oxygen concentration due to the addition of dilution gas is heated in the heat storage section and ejected into the furnace from the intake and exhaust port, and the hydrogen gas of the fuel gas that was not primarily combusted is mixed with the combustion air with a lower oxygen concentration and subjected to secondary combustion. [Diagram 2]This is a schematic explanatory diagram showing a first modified example of the regenerative combustion equipment in the above embodiment, in which dilution gas is added to the combustion air in advance, and the combustion air diluted with the dilution gas is guided to the heat storage section in the regenerative combustion burner that performs combustion operation through the air guide tube. [Diagram 3] This is a schematic explanatory diagram showing a second modified example of the regenerative combustion equipment in the above embodiment, in which the combustion exhaust gas after heat is stored in a heat storage body contained in a heat storage section of a regenerative combustion burner performing a heat storage operation is used as a dilution gas, the combustion exhaust gas is added in advance to the combustion air, and the combustion air diluted with the combustion exhaust gas is guided to the heat storage section of the regenerative combustion burner performing a combustion operation by the air guide pipe. [Figure 4] This is a schematic diagram showing a third modified example of the regenerative combustion equipment in the above embodiment, in which hydrogen gas separated from ammonia gas by an ammonia reforming separation device is used as the hydrogen gas of the fuel gas, and a dilution gas containing nitrogen gas obtained by separating hydrogen gas from ammonia gas is added to the combustion air in advance, and the combustion air diluted with the dilution gas is guided to the heat storage section in the regenerative combustion burner that performs the combustion operation by the air guide tube. BEST MODE FOR CARRYING OUT THEINVENTION

[0018] The regenerative heat combustion equipment according to the embodiment of the present invention will be specifically described below with reference to the accompanying drawings. Note that the regenerative heat combustion equipment according to the present invention is not limited to the embodiment shown below, and can be appropriately modified and implemented within the scope of the invention.

[0019] In the regenerative combustion equipment of this embodiment, as shown in Fig. 1, a pair of a first regenerative combustion burner 10a and a second regenerative combustion burner 10b are provided facing the inside of a furnace 1 which is an industrial furnace, and fuel ejection nozzles 11a and 11b are provided in each pair of regenerative combustion burners 10a and 10b, and fuel gas supply pipes 12a and 12b for supplying hydrogen gas H2 as fuel gas and combustion support gas supply pipes 13a and 13b for supplying air, oxygen gas, or other combustion support gas Gs are provided for each fuel gas supply pipe 12a and 12b, respectively. Also, opening and closing valves 121a and 121b are provided in each of the fuel gas supply pipes 12a and 12b, and opening and closing valves 131a and 131b are provided in each of the combustion support gas supply pipes 13a and 13b, respectively. Here, for all the on-off valves provided in the regenerative heat combustion equipment in the embodiment described above and described below, the open state is shown in white, and the closed state is shown in black.

[0020] As shown in FIG. 1, in the regenerative combustion burner 10a performing the combustion operation, the on-off valve 121a provided in the fuel gas supply pipe 12a is opened, and the on-off valve 131a provided in the combustion supporting gas supply pipe 13a is opened to supply hydrogen gas H2 and the combustion supporting gas Gs to the fuel injection nozzle 11a, and the hydrogen gas H2 and the combustion supporting gas Gs are injected from the fuel injection nozzle 11a into the furnace 1, so that a portion of the hydrogen gas H2 is mixed with the combustion supporting gas Gs and undergoes primary combustion in the furnace 1.

[0021] In other words, the flow rate of the combustion support gas Gs at this time is set to a flow rate that makes the combustion in a reducing state and burns only a portion of the hydrogen gas H2 (so that the hydrogen gas H2 is not completely burned).

[0022] On the other hand, in the regenerative combustion burner 10b performing the heat storage operation, the on-off valve 121b provided in the fuel gas supply pipe 12b is closed, and the on-off valve 131b provided in the combustion supporting gas supply pipe 13b is closed so that hydrogen gas H2 and combustion supporting gas Gs are not supplied to the fuel injection nozzle 11b.

[0023] In addition, in the regenerative combustion equipment of this embodiment, in each of the regenerative combustion burners 10a, 10b, air supply pipes 22a, 22b are provided to supply combustion air Air to each of the heat storage sections 20a, 20b in which the heat storage body x is housed by blowing combustion air Air using a blower 21, and dilution gas supply pipes 23a, 23b are provided to supply dilution gas Gi consisting of an inert gas such as nitrogen gas to the corresponding air supply pipes 22a, 22b, and opening / closing valves 221a, 221b are provided in each of the air supply pipes 22a, 22b, and opening / closing valves 231a, 231b are provided in each of the dilution gas supply pipes 23a, 23b.

[0024] As shown in FIG. 1, in the regenerative combustion burner 10a performing the combustion operation, the on-off valve 221a provided on the air supply pipe 22a is opened, and the on-off valve 231a provided on the dilution gas supply pipe 23a is opened, and the combustion air Air supplied through the air supply pipe 22a is diluted with the dilution gas Gi, and the combustion air Air is guided to the heat storage section 20a in which the heat storage body x is housed in a state in which the oxygen concentration is reduced, and the combustion air Air with the reduced oxygen concentration is heated by the heat stored in the heat storage body x housed in the heat storage section 20a, and is injected into the furnace 1 through the intake and exhaust port 24a in the regenerative combustion burner 10a, and mixed with the hydrogen gas H2 that was not burned by the primary combustion, to cause secondary combustion.

[0025] Here, as described above, hydrogen gas H2 and the supporting gas Gs are injected from the fuel injection nozzle 11a into the furnace 1, and a portion of the hydrogen gas H2 is primarily combusted in the furnace 1. Then, the combustion air Air, whose oxygen concentration has been reduced by the dilution gas Gi, is heated in the heat storage section 20a and injected into the furnace 1 from the intake and exhaust port 24a, where it is mixed with the hydrogen gas H2 that was not combusted in the primary combustion and subjected to secondary combustion. This prevents the hydrogen gas H2, which is the fuel gas, from being suddenly combusted all at once with the heated combustion air Air in a state where the oxygen concentration is high, as in the conventional case, and prevents the temperature of the flame during combustion from rising and NOx from being generated.

[0026] In addition, in the regenerative combustion equipment of this embodiment, when the combustion exhaust gas Gr remaining after burning the fuel gas hydrogen gas H2 as described above is exhausted from the furnace 1 through the heat storage sections 20a, 20b via the intake and exhaust ports 24a, 24b of the regenerative combustion burners 10a, 10b and the chimney 30, the combustion exhaust gas Gr guided to the heat storage sections 20a, 20b is sucked in by the suction blower 31 through the exhaust gas guide pipes 32a, 32b, and the exhaust gas guide pipes 32a, 32b are provided with opening and closing valves 321a, 321b, respectively.

[0027] 1, in the regenerative combustion burner 10a performing the combustion operation, the on-off valve 321a provided in the exhaust gas guide pipe 32a is closed so that the combustion exhaust gas Gr after burning the hydrogen gas H2 is not led from the furnace 1 to the heat storage section 20a through the intake and exhaust port 24a. On the other hand, in the regenerative combustion burner 10b performing the heat storage operation, the on-off valve 321b provided in the exhaust gas guide pipe 32b is opened so that the combustion exhaust gas Gr in the furnace 1 is sucked by the suction blower 31 and led to the heat storage section 20b through the intake and exhaust port 24b, and the heat in the combustion exhaust gas Gr is stored in the heat storage body x contained in the heat storage section 20b, and then the combustion exhaust gas Gr is led to the chimney 30 through the exhaust gas guide pipe 32b and exhausted.

[0028] In the regenerative combustion equipment of this embodiment, the pair of first regenerative combustion burner 10a and second regenerative combustion burner 10b alternately switch between the combustion operation and the regenerative operation described above.

[0029] Next, a first modification of the regenerative heat combustion facility according to the above embodiment will be described with reference to FIG.

[0030] In the regenerative combustion equipment in the second first modified example, a dilution gas Gi made of an inert gas such as nitrogen gas is mixed with the corresponding combustion air Air and introduced into the heat storage sections 20a, 20b of each regenerative combustion burner 10a, 10b. The dilution gas Gi is supplied through a dilution gas supply pipe 23 to an upstream position before the combustion air Air is blown by the blower 21 to dilute the combustion air Air, and the combustion air Air diluted by the dilution gas Gi is supplied to the air supply pipes 22a, 22b that perform the combustion operation by the blower 21.

[0031] In this way, in the regenerative combustion equipment in the first modified example, there is no need to separately install dilution gas supply pipes 23a, 23b to supply dilution gas Gi to each air supply pipe 22a, 22b, and equipment costs can be reduced.

[0032] Next, a second modification of the regenerative heat combustion facility according to the above embodiment will be described with reference to FIG.

[0033] In the regenerative combustion equipment of the second modified example, the combustion exhaust gas Gr remaining after burning hydrogen gas H2 is used as the dilution gas Gi for diluting the combustion air Air. In order to do this, the combustion exhaust gas Gr remaining after burning hydrogen gas H2 is sucked in by the suction blower 31 through each exhaust gas guide pipe 32a, 32b and guided to the chimney 30. An exhaust gas return pipe 33 is provided between the suction blower 31 and the chimney 30 to guide the combustion exhaust gas Gr sucked in by the suction blower 31 to a position upstream of the blower blower 21 that blows the combustion air Air.

[0034] In order to adjust the amount of combustion exhaust gas Gr led to a position upstream of the blower 21, a first flow control valve 331 is provided in the exhaust gas return pipe 33, and a second flow control valve 332 is provided between the exhaust gas return pipe 33 and the chimney 30 on the downstream side, so as to adjust the amount of combustion exhaust gas Gr flowing through the first flow control valve 331 and the second flow control valve 332, thereby controlling the amount of dilution gas Gi that dilutes the combustion air Air.

[0035] In this way, there is no need to prepare and supply an inert gas such as nitrogen gas separately as a dilution gas Gi to dilute the combustion air Air, which makes it possible to reduce running costs, etc.

[0036] Next, a third modification of the regenerative heat combustion facility according to the above embodiment will be described with reference to FIG.

[0037] In the regenerative combustion equipment of the third modified example, when hydrogen gas H2 as fuel gas is supplied to each fuel injection nozzle 11a, 11b of each pair of regenerative combustion burners 10a, 10b, ammonia gas NH3 is used as a raw material, and this ammonia gas NH3 is separated by an ammonia reforming separation device 40 into hydrogen gas H2 as fuel gas and dilution gas Gi containing nitrogen gas.

[0038] The hydrogen gas H2 of the fuel gas separated by the ammonia reforming separation device 40 in this manner is supplied to the fuel gas supply pipes 12a, 12b of the fuel ejection nozzles 11a, 11b through the fuel gas guide pipes 41a, 41b, respectively, while the dilution gas Gi containing nitrogen gas separated by the ammonia reforming separation device 40 is supplied to a position upstream of the blower 21 that blows the combustion air Air through the dilution gas guide pipe 42, so that the combustion air Air is diluted with the dilution gas Gi containing nitrogen gas.

[0039] In this way, ammonia gas NH3 can be effectively used as a raw material for hydrogen gas H2, which is the fuel gas, without having to separately produce hydrogen gas H2 as the fuel gas, thereby reducing the cost of producing hydrogen gas H2 as the fuel gas and making it possible to effectively use dilution gas Gi, which contains nitrogen gas separated from ammonia gas NH3. [Explanation of symbols]

[0040] 1: Furnace 10a, 10b: Regenerative combustion burner 11a, 11b: fuel injection nozzle 12a, 12b: fuel gas supply pipe 13a, 13b: Combustion support gas supply pipe 20a, 20b: Heat storage part 21: Air blower 22a, 22b: Air supply pipe 23: Dilution gas supply pipe 23a, 23b: Dilution gas supply pipe 24a, 24b: Supply / exhaust port 30: Chimney 31: Suction blower 32a, 32b: exhaust gas guide pipe 33: Exhaust gas return pipe 40: Ammonia reforming separation device 41a, 41b: fuel gas guide pipe 42: Dilution gas guide tube 121a, 121b: Opening and closing valve 131a, 131b: Opening and closing valve 221a, 221b: Opening and closing valve 231a, 231b: Opening and closing valve 321a, 321b: Opening and closing valve 331: First flow control valve 332: Second flow control valve Air: Combustion air Gi: Dilution gas Gr: Combustion exhaust gas Gs: Combustion gas H2: Hydrogen gas (fuel gas) NH3: Ammonia gas x : Heat storage body

Claims

1. In a regenerative combustion equipment, a regenerative combustion burner is provided in a pair, which performs a combustion operation in which combustion air heated through a heat storage unit containing a heat storage body is ejected from an intake and exhaust port into a furnace, and fuel gas is ejected from a fuel ejection nozzle to mix the fuel gas with the combustion air and burn it, and a regenerative combustion burner is provided in a pair, which does not eject fuel gas from the fuel ejection nozzle, and performs a heat storage operation in which the combustion exhaust gas after the fuel gas is burned is led from inside the furnace through the intake and exhaust port to the heat storage body contained in the heat storage unit, and the combustion operation and the heat storage operation are performed alternately in the pair of regenerative combustion burners, and a fuel gas using hydrogen gas and a combustion supporting gas are supplied to a fuel injection nozzle, a dilution gas is added to the combustion air introduced into a heat storage section containing the heat storage body and heated, the fuel gas using hydrogen gas and the combustion supporting gas are injected from the fuel injection nozzle into the furnace, the heated combustion air and the dilution gas are injected into the furnace from the intake and exhaust port, a part of the fuel gas using hydrogen gas is mixed with the combustion supporting gas and primary combustion is performed in the furnace, and the combustion air to which the dilution gas has been added and whose oxygen concentration has been reduced is heated in the heat storage section and injected into the furnace from the intake and exhaust port, and the hydrogen gas of the fuel gas not primarily combusted is mixed with the combustion air whose oxygen concentration has been reduced for secondary combustion.

2. 2. The regenerative combustion equipment according to claim 1, wherein an inert gas is used as the dilution gas when the dilution gas is added to the combustion air supplied to the regenerative combustion burner that performs the combustion operation.

3. 2. The regenerative combustion equipment according to claim 1, characterized in that when dilution gas is added to the combustion air supplied to the regenerative combustion burner performing the combustion operation, the dilution gas used is the combustion exhaust gas after heat has been stored in the heat storage material in the heat storage section of the regenerative combustion burner performing the heat storage operation.

4. In the regenerative combustion equipment according to any one of claims 1 to 3, when hydrogen gas of the fuel gas is supplied to the fuel injection nozzle, hydrogen gas separated from ammonia gas by an ammonia reforming separation device is supplied to the fuel injection nozzle.

5. 5. The regenerative heat combustion facility according to claim 4, wherein a gas containing nitrogen gas remaining after separating hydrogen gas from ammonia gas is used as the dilution gas.

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