JP2022114244A - Thermal storage type burning facility - Google Patents

Abstract

To provide a storage type burning facility where burning and heat storage are alternately switched in a pair of storage type burning devices, in which the generation of nitrogen oxide NOx is suppressed upon burning of ammonia as a fuel and the exhaust of NOx and unburnt ammonia NH3 to the outside is easily prevented.SOLUTION: In a heat storage type burning facility where burning and heat storage are alternately switched in a pair heat storage type burning devices 10a, 10b, ammonia NH3 is used as a fuel, and intake and exhaust 12a, 12b parts in the respective heat storage type burning devices are provided with air feed nozzles 14a, 14b for treatment feeding air for burning, and in the heat storage type burning device on the side of burning, ammonia is burnt in such a manner that the air ratio μ of air for burning to be mixed with ammonia is controlled to 1 or less, and on the other hand, the intake and exhaust parts of the respective heat storage type burning devices on the side of heat storage are fed with air for burning from the air feed nozzles for treatment.SELECTED DRAWING: Figure 1

Description

In the present invention, the heat stored in the heat storage material contained in the heat storage unit heats the combustion air, which is led into the furnace through the air supply/exhaust unit, and the combustion air is mixed with the fuel supplied from the fuel supply nozzle. and a regenerative combustion device that burns in the furnace, and a heat storage unit in which the heat storage material is accommodated, through the supply and exhaust unit, the flue gas after combustion in the furnace in a state where the supply of fuel from the fuel supply nozzle is stopped. a regenerative combustion device that stores the heat of the combustion exhaust gas in the heat storage material and discharges the combustion exhaust gas to the outside through the heat storage unit. The present invention relates to a regenerative combustion facility using ammonia as the fuel in the regenerative combustion facility for alternately switching between heat storage and heat storage. In particular, when ammonia is used as a fuel as described above and the paired regenerative combustion apparatus alternately switches between combustion and heat storage, the generation of nitrogen oxides NOx during the combustion of ammonia is suppressed, and ammonia is It is characterized in that it is sufficiently combusted, and nitrogen oxides NOx and unburned ammonia can be easily prevented from being discharged to the outside.

Conventionally, in industrial furnaces, etc., in order to perform efficient combustion using the heat of flue gas, the heat of the flue gas burned in the furnace is stored in a heat storage material stored in a heat storage unit, and burned. The combustion air is heated by the heat stored in the heat storage material in the heat storage section, and the heated combustion air is led into the furnace through the air supply and exhaust section, and supplied from the combustion air and the fuel supply nozzle. A regenerative combustion device that mixes with the fuel and burns it in the furnace, and in a state where the supply of fuel from the fuel supply nozzle is stopped, the flue gas after combustion in the furnace passes through the supply and exhaust part to the heat storage material. A regenerative combustion device that guides the heat of the combustion exhaust gas to the stored heat storage unit, stores the heat of the combustion exhaust gas in the heat storage material, and discharges the combustion exhaust gas to the outside through the heat storage unit. , regenerative combustion equipment is used in which combustion and heat storage are alternately performed.

Further, in conventional regenerative combustion equipment, when the heated combustion air and the fuel supplied from the fuel supply nozzle are mixed and burned in the furnace as described above, the fuel generally has combustibility Hydrocarbon-based fuels with high

However, in the above regenerative combustion apparatus, when a hydrocarbon fuel is mixed with combustion air and burned, there is a problem that a large amount of greenhouse gases such as carbon dioxide are generated.

In recent years, there has been a demand for reducing greenhouse gases such as carbon dioxide, and the use of fuels other than hydrocarbon fuels has been studied.

Here, conventionally, the use of ammonia, which is a low-flammability fuel, has been studied as a fuel other than the hydrocarbon-based fuel.

However, ammonia has poor combustibility compared to hydrocarbon fuels, and is prone to misfires during combustion, and also tends to generate nitrogen oxides NOx during combustion. Ammonia is also toxic and emits an irritating odor even at a mere 1 ppm, which poses a problem of having an adverse effect on the environment.

Conventionally, when burning ammonia as described above, as shown in Patent Document 1, a diffuser is arranged downstream of a burner tip that ejects the ammonia of the fuel, and ammonia is naturally sucked. The mixed ammonia and the combustion air are mixed together with the air by detouring around the diffuser, and the mixed ammonia and the combustion air are retained above the diffuser and burned to increase the combustibility of the ammonia. Alternatively, as shown in Patent Document 2, ammonia, which is a low-flammability fuel, and combustion air are premixed and homogenized, and then the premixed gas is swirled by a swirler. It has been proposed that ammonia is burned while being strongly stirred to enhance the combustibility of ammonia.

However, although the aforementioned Patent Documents 1 and 2 disclose that the combustibility of ammonia is enhanced, they have not been able to suppress the nitrogen oxides NOx generated during the combustion of ammonia.

Further, conventionally, as shown in Patent Documents 3 to 6, in the regenerative combustion equipment as described above, ammonia is jetted to a position where the combustion exhaust gas containing nitrogen oxides NOx is guided, and after combustion It has been proposed to reduce nitrogen oxide NOx contained in combustion exhaust gas.

However, in any of the above Patent Documents 1 to 6, ammonia is used as the fuel for the regenerative combustion equipment as described above, and the paired regenerative combustion equipment alternately switches between combustion and heat storage. Therefore, when burning ammonia with a regenerative combustion device, the generation of nitrogen oxides NOx is suppressed, and ammonia is reliably burned, and nitrogen oxides NOx and unburned ammonia are discharged to the outside. could not prevent it from happening.

Japanese Utility Model Publication No. 50-8257 JP 2016-130619 A JP-A-7-293815 JP-A-10-110941 JP-A-2000-65316 Japanese Patent No. 3045430

In the present invention, the heat stored in the heat storage material contained in the heat storage unit heats the combustion air, which is led into the furnace through the air supply/exhaust unit, and the combustion air is mixed with the fuel supplied from the fuel supply nozzle. and a regenerative combustion device that burns in the furnace, and a heat storage unit in which the heat storage material is accommodated, through the supply and exhaust unit, the flue gas after combustion in the furnace in a state where the supply of fuel from the fuel supply nozzle is stopped. a regenerative combustion device that stores the heat of the combustion exhaust gas in the heat storage material and discharges the combustion exhaust gas to the outside through the heat storage unit. An object of the present invention is to solve the above-mentioned problems in the case of using ammonia as the fuel in a regenerative combustion facility in which heat storage is alternately performed.

That is, in the present invention, in the regenerative combustion equipment as described above, the generation of nitrogen oxides NOx is suppressed when ammonia is burned by the regenerative combustion device, and the ammonia is reliably burned. It is therefore an object of the present invention to easily prevent nitrogen oxides NOx and unburned ammonia from being discharged to the outside.

In the regenerative combustion equipment according to the present invention, in order to solve the above problems, the combustion air is heated by the heat stored in the heat storage material contained in the heat storage unit, and guided into the furnace through the air supply and exhaust unit. , a regenerative combustion device that mixes the combustion air and fuel supplied from the fuel supply nozzle and burns it in the furnace, and after the combustion in the furnace with the supply of fuel from the fuel supply nozzle stopped The combustion exhaust gas is guided through the supply and exhaust part to a heat storage unit containing a heat storage material, the heat of the combustion exhaust gas is stored in the heat storage material, and the combustion exhaust gas is discharged to the outside through this heat storage unit. In the regenerative combustion equipment for alternately switching between combustion and heat storage in the paired regenerative combustion devices, ammonia is used as the fuel, and the air supply and exhaust part in each regenerative combustion device are provided with processing air supply nozzles that supply combustion air to each of them, and in the regenerative combustion device on the combustion side, the air ratio μ of the combustion air to be mixed with ammonia is set to 1 or less to burn ammonia, while heat storage Combustion air is supplied from the processing air supply nozzle to the air supply/exhaust part of the regenerative combustion apparatus on the side.

Here, when ammonia is used as the fuel as described above and the air ratio μ of the combustion air mixed with ammonia is set to 1 or less for combustion, the generation of nitrogen oxides NOx is suppressed during the combustion of ammonia. On the other hand, the ammonia is not completely combusted and some of the ammonia remains uncombusted. However, the ammonia left unburned in this way was led to the air supply/exhaust part of the regenerative combustion apparatus on the heat storage side together with the combustion exhaust gas, and was supplied to the air supply/exhaust part from the processing air supply nozzle. Ammonia remaining without being burned by the combustion air is burned. Here, when the air ratio μ of the combustion air to be mixed with ammonia is set to 1 or less for combustion, if the air ratio μ of the combustion air is set in the range of 0.99 to 0.94, nitrogen generated when ammonia is burned The amount of oxide NOx can be reduced and the amount of ammonia remaining unburned can be reduced. It is preferable because it will not occur.

Further, in the regenerative combustion equipment according to the present invention, as described above, the combustion air is supplied from the processing air supply nozzle to the air supply/exhaust part of the regenerative combustion device on the heat storage side, and the remaining unburned ammonia is removed. For combustion, in order to ensure that the remaining unburned ammonia is combusted by the combustion air in the air supply and exhaust section of the regenerative combustion device on the heat storage side, combustion air is supplied from the processing air supply nozzle. It is preferable to jet into the air supply/exhaust part of the regenerative combustion device on the heat storage side. Although it is possible to provide the processing air supply nozzle in the vicinity of the regenerative combustion apparatus, as described above, the combustion air is supplied from the processing air supply nozzle to the inside of the air supply and exhaust section of the regenerative combustion apparatus on the heat storage side. , almost all of the remaining unburned ammonia is reliably combusted by the combustion air supplied to the air supply/exhaust section of the regenerative combustion device on the regenerative side.

In the regenerative combustion equipment of the present invention, when alternately switching between combustion and heat storage in the paired regenerative combustion devices as described above, ammonia is used as the fuel, and the above-mentioned supply in each regenerative combustion device is performed. Processing air supply nozzles are provided to supply combustion air to the exhaust portions, respectively, and in the regenerative combustion device on the combustion side, the air ratio μ of the combustion air to be mixed with ammonia is set to 1 or less to burn ammonia. As a result, the generation of nitrogen oxides NOx is suppressed during the combustion of ammonia. When it is guided to the air supply/exhaust part of the regenerative combustion device on the heat storage side, the unburned ammonia remaining without being burned by the combustion air supplied to the air supply/exhaust part from the processing air supply nozzle is completely burned. Become so.

As a result, in the regenerative combustion equipment of the present invention, as described above, the generation of nitrogen oxides NOx during the combustion of ammonia is suppressed, and the remaining ammonia that has not been burned during combustion is completely burned. As a result, it is possible to easily prevent nitrogen oxides NOx and unburned ammonia from being discharged to the outside.

Combustion air is supplied to one of the paired regenerative combustion devices for alternately switching between combustion and heat storage in the regenerative combustion facility according to the embodiment of the present invention, using the heat stored in the heat storage material accommodated in the heat storage unit. The ammonia is heated and introduced into the furnace through the air supply and exhaust section, and the ammonia supplied from the fuel supply nozzle and the combustion air are mixed so that the air ratio μ is 1 or less, and the ammonia is burned in the furnace. Combustion air is supplied from the processing air supply nozzle to the air supply/exhaust part on the way of leading the flue gas of one to the heat storage part of the other regenerative combustion device, and unburned ammonia in the flue gas is burned. FIG. 4 is a schematic cross-sectional explanatory view showing a state in which the heat of combustion exhaust gas is stored in a heat storage material and the combustion exhaust gas is discharged to the outside through this heat storage unit. In the regenerative combustion equipment according to the same embodiment, the one regenerative combustion device and the other regenerative combustion device switch between combustion and heat storage, and the other regenerative combustion device has an air ratio μ of 1 or less. While ammonia is burned in the furnace in this manner, combustion air is supplied from a processing air supply nozzle to the air supply/exhaust part of one of the regenerative combustion devices to burn unburned ammonia in the combustion exhaust gas. 1 is a schematic cross-sectional explanatory view showing a state in which the heat of combustion exhaust gas is stored in a heat storage material and the combustion exhaust gas is discharged to the outside through this heat storage unit.

Hereinafter, a regenerative combustion facility according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. It should be noted that the regenerative combustion equipment according to the present invention is not limited to those shown in the following embodiments, and can be modified as appropriate without changing the gist of the invention.

In the regenerative combustion equipment of this embodiment, as shown in FIGS. Combustion and heat storage are alternately performed in the regenerative combustion devices 10a and 10b.

When combustion is performed in each of the regenerative combustion devices 10a and 10b, the combustion air Air is guided to the heat storage units 11a and 11b in which the heat storage material x is accommodated, respectively, and the heat is stored in the heat storage material x. Combustion air Air is heated by heat and supplied into the furnace 1 through the respective air supply and exhaust units 12a and 12b, and provided near the air supply and exhaust units 12a and 12b in the regenerative combustion devices 10a and 10b. Ammonia NH ₃ as fuel is supplied from the fuel supply nozzles 13a and 13b to the vicinity of the air supply/exhaust units 12a and 12b, respectively, so that the air ratio μ of the combustion air Air supplied as described above is 1 or less. , is mixed with the combustion air Air and burned in the furnace 1 .

On the other hand, when heat is stored in each of the regenerative combustion devices 10a and 10b, the flue gas after combustion in the furnace 1 is discharged while the supply of fuel from the fuel supply nozzles 13a and 13b is stopped. The heat of the flue gas is guided to the heat storage units 11a and 11b containing the heat storage material x through the air supply/exhaust units 12a and 12b, respectively, and the heat of the combustion exhaust gas is stored in the heat storage material x. Combustion exhaust gas is discharged to the outside.

Here, in the regenerative combustion equipment in this embodiment, as shown in FIGS. For this purpose, on-off valves 21a and 21b are provided in portions of an air guide path 21 for guiding combustion air Air from the air supply device 20 toward the heat storage units 11a and 11b in the regenerative combustion devices 10a and 10b, respectively.

Then, the on-off valves 21a and 21b are opened and closed by a control device (not shown), and the air is supplied from the air supply device 20 through the air guide path 21 to the heat storage units 11a and 11b in the regenerative combustion devices 10a and 10b. The supply and stop of the combustion air Air are switched. Here, with respect to the on-off valves 21a and 21b, the open state is shown in white, while the closed state is shown in black.

Further, in the regenerative combustion equipment according to this embodiment, processing air supply nozzles 14a and 14b are provided in the air supply/exhaust units 12a and 12b of the regenerative combustion devices 10a and 10b, respectively. On-off valves 22a and 22b are provided in portions of the processing air guide path 22 that guides the combustion air Air from the air supply device 20 to 14b, respectively.

The on-off valves 22a and 22b are opened and closed by a control device (not shown), and the processing air is supplied from the air supply device 20 through the processing air guide path 22 to the processing air supply nozzles 14a and 14b. He is trying to switch supply and stop of combustion air Air. Here, with regard to the on-off valves 22a and 22b as well, the open state is shown in white, while the closed state is shown in black.

Further, in the regenerative combustion equipment in this embodiment, as described above, ammonia NH ₃ as fuel is supplied from the fuel supply nozzles 13a, 13b provided in the vicinity of the air supply/exhaust units 12a, 12b in the regenerative combustion devices 10a, 10b. is supplied into the furnace 1, on-off valves 31a and 31b are provided in the portions of the fuel guide path 31 that guide the ammonia _NH3 to the fuel supply nozzles 13a and 13b, respectively.

Then, the opening/closing valves 31a and 31b are opened and closed by a control device (not shown) to switch between supply and stop of ammonia _NH3 supplied to the fuel supply nozzles 13a and 13b through the fuel guide path 31. I have to. Here, with respect to the on-off valves 31a and 31b as well, the open state is shown in white, while the closed state is shown in black.

Further, in the regenerative combustion equipment in this embodiment, as described above, in the regenerative combustion devices 10a and 10b, the combustion exhaust gas in the furnace 1 after burning the ammonia NH ₃ is When the combustion exhaust gas is sucked from the air supply/exhaust units 12a and 12b of the combustion devices 10a and 10b through the heat storage units 11a and 11b in which the heat storage material x is accommodated and is exhausted to the outside, the combustion exhaust gas is introduced into the heat storage units of the regenerative combustion devices 10a and 10b. On-off valves 41a and 41b are provided in portions of the exhaust path 41 leading to the exhaust device 40 through 11a and 11b, respectively.

A control device (not shown) opens and closes the on-off valves 41a and 41b to switch the regenerative combustion devices 10a and 10b that lead the combustion exhaust gas to the exhaust device 40 through the exhaust path 41. FIG. Here, with respect to the on-off valves 41a and 41b as well, the open state is shown in white, while the closed state is shown in black.

In the regenerative combustion equipment of this embodiment, one regenerative combustion device 10a burns ammonia NH ₃ while the other regenerative combustion device 10b stores the heat of combustion exhaust gas and discharges the combustion exhaust gas. , in one regenerative combustion device 10a for burning ammonia _NH3 , as shown in FIG. The combustion air Air is guided to the heat storage section 11a in one of the regenerative combustion devices 10a, and the combustion air Air is heated by the heat storage material x stored in the heat storage section 11a. , the ammonia NH 3 is supplied into the furnace 1 through the air supply/exhaust part 12a of the regenerative combustion apparatus 10a, and one opening/closing valve 31a provided in the fuel guide path 31 is opened to allow ammonia NH ₃ to flow through the fuel guide path 31. One fuel supply nozzle 13a is introduced, and ammonia NH ₃ is injected from this fuel supply nozzle 13a toward the combustion air Air supplied into the furnace ₁ through the air supply/exhaust part 12a. are mixed and burned so that the air ratio μ of the heated combustion air Air is 1 or less.

In this way, when ammonia NH ₃ is mixed and burned so that the air ratio μ of the combustion air Air is 1 or less, the generation of nitrogen oxides NOx during combustion is suppressed. When the ratio μ is in the range of 0.99 to 0.94, the amount of nitrogen oxides NOx generated when ammonia NH ₃ is burned can be reduced, and the amount of unburned ammonia remaining without being burned can be reduced. Furthermore, when the air ratio μ of the combustion air is set to approximately 0.95, almost no nitrogen oxides NOx are generated during the combustion of ammonia.

On the other hand, in the other regenerative combustion device 10b for accumulating the heat of the combustion exhaust gas and discharging the combustion exhaust gas as described above, the other opening/closing valve 41b provided in the exhaust passage 41 is opened to release ammonia as described above. The combustion exhaust gas containing unburned ammonia NH ₃ after burning NH ₃ with the combustion air Air so that the air ratio μ is 1 or less is discharged from the exhaust path 41 to the other heat storage by the exhaust device 40. At the same time, the other opening/closing valve 22b provided in the processing air guide path 22 is opened to allow the combustion air Air to flow through the other processing air supply nozzle. 14b to the air supply/exhaust part 12b, the unburned ammonia NH ₃ contained in the combustion exhaust gas was burned with this combustion air Air, and the combustion exhaust gas and the unburned ammonia NH ₃ were burned. The combustion exhaust gas is sucked together with the combustion exhaust gas into the heat storage section 11b in the other regenerative combustion device 10b, and after the heat of these combustion exhaust gases is accumulated in the heat storage material x, the combustion exhaust gas is discharged through the exhaust path 41. It is guided to the device 40 and exhausted to the outside.

Here, as described above, one regenerative combustion device 10a burns ammonia _{NH3 ,} while the other regenerative combustion device 10b stores the heat of the combustion exhaust gas and exhausts it. At the same time, the generation of nitrogen oxides NOx is suppressed, and the unburned ammonia _NH3 remaining unburned during the combustion is also burned in the heat storage side air supply/exhaust part 12a as described above. , the combustion exhaust gas containing nitrogen oxides NOx and unburned ammonia can be easily prevented from being discharged to the outside by the exhaust device 40 .

_In addition, in the regenerative combustion equipment in this embodiment, contrary to the case of FIG. When the heat is accumulated and the combustion exhaust gas is discharged, as shown in FIG. Combustion air Air is led from the device 20 to the heat storage section 11b of the other regenerative combustion device 10a, and this combustion air Air is heated by the heat storage material x stored in the heat storage section 11b, and the combustion thus heated is achieved. Ammonia NH ₃ is introduced to the other fuel supply nozzle 13b, and ammonia NH ₃ is injected from this fuel supply nozzle 13b toward the combustion air Air supplied into the furnace 1 through the air supply/exhaust part 12b, and this ammonia NH ₃ are mixed and burned so that the air ratio μ of the heated combustion air Air is 1 or less.

Further, in one of the regenerative combustion devices 10a for accumulating the heat of the combustion exhaust gas and discharging the combustion exhaust gas as described above, one opening/closing valve 41a provided in the exhaust path 41 is opened, and ammonia is discharged as described above. The combustion exhaust gas containing unburned ammonia NH ₃ after burning NH ₃ with the combustion air Air in such a manner that the air ratio μ is 1 or less is discharged from the exhaust path 41 to one side by the exhaust device 40. At the same time, one opening/closing valve 22a provided in the processing air guide path 22 is opened to allow the combustion air Air to flow through one of the processing air supply nozzles. 14a to the air supply/exhaust part 12a, the unburned ammonia NH ₃ contained in the combustion exhaust gas was burned with this combustion air Air, and the combustion exhaust gas and the unburned ammonia NH ₃ were burned. The combustion exhaust gas is sucked together with the combustion exhaust gas into the heat storage unit 11a in one regenerative combustion device 10a, and after the heat of the combustion exhaust gas is accumulated in the heat storage material x, the combustion exhaust gas is discharged through the exhaust path 41. It is guided to the device 40 and exhausted to the outside.

In this manner, while the ammonia NH ₃ is burned in the other regenerative combustion device 10b, the heat of the flue gas is accumulated in the regenerative combustion device 10a and the flue gas is exhausted. As in the case shown, the generation of nitrogen oxides NOx is suppressed during the combustion of ammonia NH ₃ , and the unburned ammonia NH 3 remaining unburned during the combustion of ammonia NH ₃ is also removed from the heat storage side air supply/exhaust part 12a. It is possible to easily prevent combustion exhaust gas containing nitrogen oxides NOx and unburned ammonia from being discharged to the outside by the exhaust device 40.

Reference Signs List 1: Furnace 10a: Regenerative Combustion Device 10b: Regenerative Combustion Device 11a: Heat Storage Unit 11b: Heat Storage Unit 12a: Supply/Exhaust Unit 12b: Supply/Exhaust Unit 13a: Fuel Supply Nozzle 13b: Fuel Supply Nozzle 14a: Processing Air Supply Nozzle 14b: processing air supply nozzle 20: air supply device 21: air guide path 21a: on-off valve 21b: on-off valve 22: processing air guide path 22a: on-off valve 22b: on-off valve 31: fuel guide path 31a: on-off valve 31b : On-off valve 40 : Exhaust device 41 : Exhaust path 41a : On-off valve 41b : On-off valve Air : Combustion air NH ₃ : Ammonia x : Heat storage material

Claims (3)

Combustion air is heated by the heat stored in the heat storage material accommodated in the heat storage unit and guided into the furnace through the air supply/exhaust unit. and the combustion exhaust gas after combustion in the furnace is guided through the supply and exhaust part to the heat storage part containing the heat storage material in a state where the supply of fuel from the fuel supply nozzle is stopped. A regenerative combustion device that stores the heat of the exhaust gas in a heat storage material and discharges the combustion exhaust gas to the outside through the heat storage unit is provided in a pair, and the paired regenerative combustion device alternately performs combustion and heat storage. in the regenerative combustion equipment, wherein ammonia is used as the fuel, processing air supply nozzles are provided to supply combustion air to the air supply and exhaust units in each regenerative combustion device, and the combustion side is In the regenerative combustion apparatus, the air ratio μ of the combustion air to be mixed with ammonia is set to 1 or less, and ammonia is burned, while the processing air supply nozzle is fed to the air supply/exhaust part of the regenerative combustion apparatus on the heat storage side. Regenerative combustion equipment characterized by supplying combustion air. In the regenerative combustion equipment according to claim 1, when the ammonia and the combustion air are mixed and burned, the air ratio μ of the combustion air is set in the range of 0.99 to 0.94. Regenerative combustion equipment. 3. The regenerative combustion equipment according to claim 1, wherein the processing air supply nozzle is provided in the air supply/exhaust part of each of the regenerative combustion devices, and heat is stored on the heat storage side from the processing air supply nozzle. A regenerative combustion facility characterized by jetting combustion air into an air supply/exhaust part of a combustion system.

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