JP7387243B2 - Ammonia fuel combustion equipment - Google Patents

Description

The present invention relates to an ammonia fuel combustion apparatus that mixes ammonia fuel with combustion air and burns the mixture in a furnace using a burner. In particular, when ammonia fuel (e.g. ammonia gas) is mixed with combustion air and burned in a furnace using a burner, reformed ammonia fuel, which has improved combustibility by reforming the ammonia fuel, is mixed with the combustion air. The present invention is characterized in that stable combustion can be performed even at low temperatures, and combustion by reformed ammonia fuel can be controlled to suppress the generation of NOx during combustion.

BACKGROUND ART Combustion devices that mix fuel with combustion air and combust it generally use hydrocarbon fuel as the fuel.

However, when a hydrocarbon fuel is mixed with combustion air and combusted in a combustion device in this manner, there is a problem in that a large amount of greenhouse gases such as carbon dioxide are generated.

In recent years, there has been a desire to reduce greenhouse gases such as carbon dioxide, and consideration has been given to using fuels other than hydrocarbon fuels.

In addition, it has been known to use ammonia fuel as a fuel in combustion devices, but ammonia fuel has poor combustibility compared to hydrocarbon fuels, is difficult to completely burn, and is difficult to burn at low temperatures. On the other hand, if the fuel is burned strongly, the flame temperature becomes high and the amount of NOx generated increases.

In order to burn ammonia fuel with poor flammability, Patent Document 1 discloses that a part of the ammonia fuel is thermally decomposed into hydrogen gas and nitrogen gas, and the hydrogen gas and nitrogen gas are mixed with the remaining ammonia fuel. In this example, the reformed ammonia fuel is mixed with combustion air and combusted.

Furthermore, Patent Document 2 discloses an ammonia decomposition catalyst that decomposes ammonia fuel into hydrogen gas and nitrogen gas.

Here, as shown in the above-mentioned Patent Document 2, when hydrogen gas and nitrogen gas obtained by decomposing ammonia fuel using an ammonia decomposition catalyst are mixed with combustion air and burned in a furnace with a burner. However, when the temperature inside the furnace becomes high (approximately 800° C. or higher), the amount of NOx contained in the combustion exhaust gas increases rapidly, which poses a problem in that it harms the environment.

Japanese Patent Application Publication No. 7-331265 Japanese Patent Application Publication No. 2012-5926

An object of the present invention is to solve the above-mentioned problems in an ammonia fuel combustion apparatus in which ammonia fuel is mixed with combustion air and combusted in a furnace using a burner.

That is, the present invention improves combustibility by improving the combustibility of the ammonia fuel when mixing the ammonia fuel with combustion air and burning it in the furnace using a burner as described above. The object of the present invention is to mix it with combustion air to enable stable combustion even at low temperatures, and to control combustion by reformed ammonia fuel to suppress the generation of NOx during combustion.

In an ammonia fuel combustion apparatus according to the present invention, in order to solve the above problems, in an ammonia fuel combustion apparatus in which ammonia fuel is mixed with combustion air and combusted in a furnace by a burner, the ammonia fuel is mixed with a reformer. a first supply path that decomposes a part of the ammonia fuel into hydrogen gas and nitrogen gas and supplies reformed ammonia fuel containing the decomposed hydrogen gas and nitrogen gas to the burner; and a second supply path for supplying ammonia to the furnace, and an in-furnace environment detection sensor for detecting the environmental condition in the furnace, and based on the result detected by the in-furnace environment detection sensor, the controller controls the supply of ammonia. The first supply path and the second supply path for supplying fuel to the burner are controlled.

Here, in the ammonia fuel combustion apparatus according to the present invention, the reformer includes a catalytic reforming section that houses a catalyst that decomposes ammonia fuel into hydrogen gas and nitrogen gas, and a catalytic reformer that houses a catalyst that decomposes ammonia fuel into hydrogen gas and nitrogen gas. At least one of a heating reforming section that decomposes hydrogen gas and nitrogen gas can be provided.

Further, in the ammonia fuel combustion apparatus according to the present invention, the in-furnace environment detection sensor includes an in-furnace temperature detection sensor that detects the temperature in the furnace, and a NOx concentration detection sensor that detects the NOx concentration in the furnace. At least one can be provided.

Moreover, in the ammonia fuel combustion apparatus according to the present invention, whether the temperature inside the furnace detected by the above-mentioned furnace temperature detection sensor increases or the NOx concentration detected by the above-mentioned NOx concentration detection sensor increases. In accordance with at least one, the controller decreases the amount of reformed ammonia fuel delivered to the burner through the first supply path while increasing the amount of ammonia fuel delivered to the burner through the second supply path. You can do it like this.

Here, the control device causes the first If the amount of reformed ammonia fuel supplied to the burner through the supply channel is decreased and the amount of ammonia fuel supplied to the burner through the second supply channel is increased, combustion by the reformed ammonia fuel will be reduced, and the Even if the temperature becomes high, the generation of NOx during combustion is suppressed.

In the ammonia fuel combustion apparatus according to the present invention, either the temperature inside the furnace detected by the furnace temperature detection sensor rises to a predetermined temperature, or the NOx concentration detected by the NOx concentration detection sensor increases to a predetermined value. In at least one of the above cases, the controller stops supplying the reformed ammonia fuel to the burner through the first supply path, and supplies the ammonia fuel to the burner through the second supply path. It is preferable to supply only In this way, since the temperature inside the furnace is rising, the ammonia fuel supplied to the burner is properly combusted within the furnace, and the reformed ammonia fuel is no longer combusted, so that Even if the internal temperature becomes high, the generation of NOx during combustion is suppressed.

In the ammonia fuel combustion apparatus of the present invention, as described above, ammonia fuel is guided to the reformer through the ammonia supply pipe to decompose a part of the ammonia fuel into hydrogen gas and nitrogen gas, and the decomposed hydrogen gas and nitrogen gas are decomposed. A first supply path for supplying reformed ammonia fuel containing gas to the burner, and a second supply path for supplying the ammonia fuel as it is to the burner through the ammonia supply pipe are provided. Since the control device controls the first supply path and the second supply path for supplying ammonia fuel to the burner based on the environmental condition inside the furnace, hydrogen gas decomposed by the reformer passes through the first supply path. By supplying reformed ammonia fuel containing nitrogen gas and nitrogen gas to the burner and burning it, stable combustion can be achieved even when the temperature inside the furnace is low, but if the temperature inside the furnace rises, By supplying the ammonia fuel to the burner through the second supply path and combusting it, the generation of NOx during combustion is suppressed even if the temperature inside the furnace becomes high.

As a result, in the ammonia fuel combustion apparatus of the present invention, when the ammonia fuel is mixed with combustion air and burned in the furnace by the burner, the ammonia fuel is mixed with hydrogen gas and nitrogen gas, which are partially decomposed ammonia fuel. By mixing reformed ammonia fuel with combustion air, stable combustion can be achieved even at low temperatures, and when the temperature inside the furnace rises, combustion with reformed ammonia fuel is controlled to reduce NOx during combustion. It becomes possible to suppress the occurrence of

1 is a schematic explanatory diagram of an ammonia fuel combustion apparatus according to an embodiment of the present invention. The state of use of the ammonia fuel combustion apparatus according to the above embodiment is shown, and (A) shows hydrogen gas and nitrogen gas decomposed by the reformer flowing through the first supply path when the temperature inside the furnace is low. A schematic explanatory diagram showing a state in which only reformed ammonia fuel is supplied to the burner and burned. (B) shows the amount of reformed ammonia fuel supplied to the burner through the first supply path when the temperature inside the furnace rises. (C) is a schematic explanatory diagram showing a state in which ammonia fuel is supplied to the burner through the second supply path and burned while reducing the NOx concentration in the furnace. It is a schematic explanatory view showing the state where supply of ammonia fuel to a burner is stopped, and only ammonia fuel is supplied to a burner through a 2nd supply path, and it burns.

EMBODIMENT OF THE INVENTION Hereinafter, the ammonia fuel combustion apparatus based on embodiment of this invention is concretely demonstrated based on an accompanying drawing. Note that the ammonia fuel combustion apparatus according to the present invention is not limited to the embodiments shown below, and can be implemented with appropriate modifications without changing the gist of the invention.

In the ammonia fuel combustion apparatus according to the _{embodiment of} the present invention, as shown in FIG. A portion of NH ₃ is decomposed into hydrogen gas H ₂ and nitrogen gas N ₂ , and reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) containing the decomposed hydrogen gas H ₂ and nitrogen gas N ₂ is sent to the burner 30. A first supply path 11 is provided to supply the ammonia fuel NH ₃ to the burner 30 as it is, and a second supply path 12 is provided to directly supply the ammonia fuel NH 3 to the burner 30. A second control valve 12a is provided in the second supply passage 12 to control the amount of ammonia fuel _NH3 introduced to the reformer 20 through the passage 11, and the amount of ammonia fuel _NH3 introduced to the burner 30 through the second supply passage 12 is controlled. I try to control the amount.

Here, in the reformer 20, a catalytic reforming section 21 containing a catalyst for decomposing ammonia fuel NH ₃ into hydrogen gas H ₂ and nitrogen gas N ₂ is provided inside the reformer 20, and this catalyst A heating reforming section 22 is used that heats the ammonia fuel NH ₃ introduced into the reforming section 21 to activate the decomposition action of the ammonia fuel NH ₃ . In this embodiment, the reformer 20 has both the catalyst reforming section 21 and the heating reforming section 22 as described above, but the catalyst does not need to be activated by heating. Since ammonia fuel NH ₃ also has a decomposition effect and decomposes even when heated, it is also possible to use either the catalytic reforming section 21 or the heating reforming section 22 alone.

Combustion air Air is supplied to the burner 30 through the air supply pipe 40, and the reformed ammonia fuel (NH ₃ + H ₂ + N ₂ ) and ammonia fuel NH ₃ introduced to the burner 30 through the second supply path 12, and the mixture is combusted in the furnace 1 by the burner 30.

In addition, in the ammonia fuel combustion apparatus in this embodiment, as the in-furnace environment detection sensor 50 that detects the environmental state in the furnace 1, an in-furnace temperature detection sensor 51 that detects the temperature in the furnace 1, and an in-furnace temperature detection sensor 51 that detects the temperature in the furnace 1, The temperature inside the furnace 1 and the NOx concentration inside the furnace 1 detected by the inside temperature detection sensor 51 and the NOx concentration detection sensor 52 are sent to the control device 60. The controller 60 controls the first control valve 11a provided in the first supply path 11 and the second control valve 12a provided in the second supply path 12. . It should be noted that each of the control valves 11a and 12a is shown in white when it is open, and in black when it is closed.

Here, in the ammonia fuel combustion apparatus in this embodiment, the temperature inside the furnace 1 detected by the above-mentioned furnace temperature detection sensor 51 is low, such as in the initial stage of starting combustion of the ammonia fuel _NH3 . In some cases, it is difficult to combust the ammonia fuel NH ₃ as it is, so as shown in FIG. 12a is closed to prevent ammonia fuel NH ₃ from being supplied to the burner 30 from the second supply path 12, while the first control valve 11a provided in the first supply path 11 is opened to prevent ammonia fuel from being supplied through the ammonia supply pipe 10. The ammonia fuel NH ₃ is introduced into the reformer 20 having the catalytic reforming section 21 and the heating reforming section 22 provided in the first supply path 11 .

In the reformer 20, a part of the ammonia fuel _NH3 is decomposed into hydrogen gas _H2 and nitrogen gas _N2 , and the hydrogen gas _H2 and nitrogen gas _N2 are supplied through the first supply path 11. The reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) containing the fuel is supplied to the burner 30, mixed with the combustion air Air supplied to the burner 30 through the air supply pipe 40, and combusted in the furnace 1. ing.

In this way, since the reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) contains highly combustible hydrogen gas H ₂ in addition to the ammonia fuel NH ₃ , only the ammonia fuel NH ₃ can be used. Compared to the case where the mixture is mixed with combustion air and combusted, the combustibility is improved and stable combustion can be performed.

Next, as described above, the reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) is mixed with combustion air Air and burned in the furnace 1 by the burner 30, resulting in a temperature detected by the furnace temperature detection sensor 51. When the temperature inside the furnace 1 rises to a predetermined temperature (a temperature at which NOx begins to be generated), the control device 60 controls the temperature at which the The second control valve 12a is controlled to adjust the amount of ammonia fuel _NH3 supplied from the ammonia supply pipe 10 to the second supply path 12, and an appropriate amount of ammonia fuel _NH3 is supplied through the second supply path 12. The ammonia fuel NH3 is supplied to the burner 30, and the first control valve 11a provided in the first supply path 11 is controlled to adjust the _amount of ammonia fuel NH3 supplied to the first supply path 11 through the ammonia supply pipe 10. A suitable amount of ammonia fuel NH ₃ is introduced into the reformer 20 through the first supply path 11 to decompose a part of the ammonia fuel NH ₃ into hydrogen gas H ₂ and nitrogen gas N ₂ . A reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) containing hydrogen gas H ₂ and nitrogen gas N ₂ is supplied to the burner 30 through the burner 30 .

The ammonia fuel NH ₃ supplied to the burner 30 through the second supply path 12 as described above and the reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) supplied to the burner 30 through the first supply path 11 are then The air is mixed with the combustion air supplied to the burner 30 through the air supply pipe 40, and is combusted in the furnace 1.

In this way, the ammonia fuel NH ₃ is stably combusted together with the reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) in the furnace 1 that has been heated to a predetermined temperature, and the The amount of ammonia fuel NH ₃ introduced to the reformer 20 through the first supply path 11 can be reduced, and the ammonia fuel NH ₃ is reformed into reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) by the reformer 20. It will be possible to reduce costs such as electricity bills and extend the life of the catalyst.

Further, when the ammonia fuel NH ₃ and the reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) are mixed with the combustion air Air and burned in the furnace 1 by the burner 30 as described above, the above-mentioned furnace When the temperature inside the furnace 1 detected by the internal temperature detection sensor 51 becomes high enough to generate NOx, or when the NOx concentration detected by the NOx concentration detection sensor reaches a predetermined value, the temperature in FIG. ), the control device 60 closes the first control valve 11a provided in the first supply path 11, and ammonia fuel NH ₃ is supplied from the ammonia supply pipe 10 to the first control valve 11a provided in the first supply path 11. On the other hand, the second control valve 12a provided in the second supply path 12 is opened to supply ammonia fuel NH ₃ to the burner 30 from the ammonia supply pipe 10 through the second supply path 12. The air is mixed with the combustion air Air supplied to the burner 30 through the air supply pipe 40, and is combusted in the furnace 1.

In this way, the ammonia fuel NH ₃ supplied to the burner 30 through the second supply path 12 is mixed with the combustion air Air, and is appropriately combusted in the furnace 1 where the temperature has become high. Compared to the case of burning reformed ammonia fuel (NH ₃ + H ₂ + N ₂ ), even if the combustion temperature during combustion becomes high, the generation of NOx is suppressed, and the environment is prevented from being harmed by NOx. In addition, it is possible to eliminate the cost of reforming ammonia fuel NH ₃ into reformed ammonia fuel (NH ₃ +H ₂ +N ₂ ) using the reformer 20.

1: Furnace 10: Ammonia supply pipe 11: First supply path 11a: First control valve 12: Second supply path 12a: Second control valve 20: Reformer 21: Catalytic reformer 22: Heating reformer 30 : Burner 40 : Air supply pipe 50 : Furnace environment detection sensor 51 : Furnace temperature detection sensor 52 : NOx concentration detection sensor 60 : Control device Air : Combustion air H ₂ : Hydrogen gas N ₂ : Nitrogen gas NH ₃ : Ammonia Fuel (ammonia gas)
NH ₃ +H ₂ +N ₂ : Reformed ammonia fuel

Claims (5)

In an ammonia fuel combustion device that mixes ammonia fuel with combustion air and burns it in a furnace using a burner, the ammonia fuel is led to a reformer through an ammonia supply pipe and a part of the ammonia fuel is decomposed into hydrogen gas and nitrogen gas. a first supply path for supplying reformed ammonia fuel containing decomposed hydrogen gas and nitrogen gas to the burner; and a second supply path for supplying the ammonia fuel as it is to the burner through the ammonia supply pipe. , an in-furnace environment detection sensor for detecting an environmental state in the furnace is provided, and a control device supplies ammonia fuel to the burner based on the result detected by the in-furnace environment detection sensor. An ammonia fuel combustion device characterized by controlling a first supply path and a second supply path. 2. The ammonia fuel combustion apparatus according to claim 1, wherein the reformer includes a catalytic reformer containing a catalyst that decomposes ammonia fuel into hydrogen gas and nitrogen gas; 1. An ammonia fuel combustion device comprising at least one of the following: and a heating reformer for decomposing the fuel into nitrogen gas. In the ammonia fuel combustion apparatus according to claim 1 or 2, the in-furnace environment detection sensor includes an in-furnace temperature sensor that detects the temperature inside the furnace, and a NOx concentration sensor that detects the NOx concentration in the furnace. An ammonia fuel combustion device comprising at least one of a sensor and a sensor. 4. The ammonia fuel combustion apparatus according to claim 3, wherein at least the temperature inside the furnace detected by the furnace temperature detection sensor increases, or the NOx concentration detected by the NOx concentration detection sensor increases. According to one aspect, said controller reduces the amount of reformed ammonia fuel fed to the burner through said first feed path, while increasing the amount of ammonia fuel fed to the burner through said second feed path; An ammonia fuel combustion device featuring: In the ammonia fuel combustion apparatus according to claim 3, either the temperature inside the furnace detected by the furnace temperature detection sensor rises to a predetermined temperature, or the NOx concentration detected by the NOx concentration detection sensor increases to a predetermined value. is reached, the control device stops supplying the reformed ammonia fuel to the burner through the first supply path and supplies only ammonia fuel to the burner through the second supply path. An ammonia fuel combustion device characterized by supplying.

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