Combustion device

Abstract

To provide a combustion device capable of predicting leakage of unburnt ammonia to exhaust gas and surely detecting it at an early stage in a combustion device for burning ammonia decomposition gas.SOLUTION: A combustion device includes: a burner that combusts an ammonia decomposition gas; a fuel supply line that supplies the ammonia decomposition gas to the burner; an air supply line that supplies combustion air to the burner; an exhaust gas line through which exhaust gas after combustion of the ammonia decomposition gas flows; a hydrogen concentration detection unit provided in the exhaust gas line for detecting the hydrogen concentration in the exhaust gas: and a control unit that controls the combustion device. The control unit includes a first storage unit that stores a relationship between the hydrogen concentration in the exhaust gas and the ammonia discharge state, and an ammonia discharge evaluation unit that evaluates the ammonia discharge state in the exhaust gas based on the detection result of the hydrogen concentration detection unit and the relationship between the hydrogen concentration in the exhaust gas and the ammonia discharge state stored in the first storage unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, from the viewpoint of reducing carbon dioxide emissions, the use of ammonia fuel, which does not generate carbon dioxide when burned, has been widespread. Among combustion devices that use ammonia fuel, there are those that decompose ammonia fuel into nitrogen and hydrogen to produce ammonia decomposition gas fuel, which is then mixed with combustion air and burned (see, for example, Patent Documents 1 and 2). Patent Document 1 describes that the system further includes a second ammonia decomposition device for further decomposing residual ammonia in the gas flowing from the first ammonia decomposition device to the combustion unit, or an ammonia separation device for separating the residual ammonia in the gas, thereby suppressing the emission of unburned ammonia and the generation of NOx in the combustion section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-095512 [Patent Document 2] Japanese Patent Publication No. 2022-015464 Summary of the Invention [Problem to be solved by the invention]

[0004] When ammonia decomposition gas is burned, if the air ratio, combustion temperature, etc. deviate from the appropriate combustion range, unburned ammonia may remain in the exhaust gas and be emitted outside the system. The control standard for ammonia concentration is low, at 1 to 2 ppm at the site boundary (the boundary between the site of a factory, etc. and the outside), and when ammonia is detected by an exhaust gas analyzer, it is likely that the control standard value is already close to or has been exceeded. Therefore, it is desirable to be able to detect unburned ammonia leakage early and reliably in combustion equipment that burns ammonia decomposition gas.

[0005] An object of the present invention is to provide a combustion device that burns ammonia decomposition gas, which is capable of predicting leakage of unburned ammonia into exhaust gas and reliably detecting it at an early stage. [Means for solving the problem]

[0006] The present invention solves the above problems by the following means.

[0007] The combustion device of the present invention is a combustion device that combusts ammonia decomposition gas, and includes: a burner that combusts the ammonia decomposition gas; a fuel supply line that supplies the ammonia decomposition gas to the burner; an air supply line that supplies combustion air to the burner; an exhaust gas line that circulates exhaust gas after combustion of the ammonia decomposition gas; a hydrogen concentration detection unit that is provided in the exhaust gas line and detects the hydrogen concentration in the exhaust gas; and a control unit that controls the combustion device, wherein the control unit includes: a first memory unit that stores the relationship between the hydrogen concentration in the exhaust gas and an ammonia emission state; and an ammonia emission evaluation unit that evaluates the ammonia emission state in the exhaust gas based on the detection result of the hydrogen concentration detection unit and the relationship between the hydrogen concentration in the exhaust gas and the ammonia emission state stored in the first memory unit.

[0008] Furthermore, it is preferable that the combustion device includes a combustion condition setting unit that sets combustion conditions including at least one of a combustion amount and an ammonia concentration in the ammonia decomposition gas, the first memory unit stores a relationship between the hydrogen concentration in the exhaust gas and an ammonia emission state, further correlated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas, and the ammonia emission evaluation unit evaluates the ammonia emission state based on the detection result of the hydrogen concentration detection unit, the setting result of the combustion condition setting unit, and the relationship between the hydrogen concentration in the exhaust gas and the ammonia emission state, which is further correlated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas stored in the first memory unit.

[0009] Preferably, the control unit includes a second storage unit that stores a control value, which is indicated by the hydrogen concentration in the exhaust gas and controls the ammonia discharge state, in association with a control corresponding to the control value.

[0010] Furthermore, it is preferable that the combustion device includes a control value correspondence control unit that controls at least one of stopping combustion in the burner, adjusting the air ratio in combustion in the burner, and issuing an alarm based on the control value, and that the control value correspondence control unit controls the combustion device based on the detection result of the hydrogen concentration detection unit and control corresponding to the control value stored in the second memory unit.

[0011] Furthermore, it is preferable that the control unit includes an air ratio control unit that adjusts at least one of the supply amount of the combustion air supplied to the burner and the supply amount of the ammonia decomposition gas supplied to the burner, thereby controlling the air ratio in combustion in the burner, and an exhaust gas ammonia generation threshold evaluation unit that temporarily reduces the air ratio by the air ratio control unit until the ammonia emission evaluation unit evaluates that a predetermined ammonia emission state is reached, and evaluates the air ratio at which the predetermined ammonia emission state is reached. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a combustion apparatus that burns ammonia decomposition gas, which is capable of predicting leakage of unburned ammonia into exhaust gas and reliably detecting it at an early stage. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating the configuration of a combustion device of a first embodiment and a boiler equipped with the same. FIG. [Figure 2] FIG. 2 is a diagram showing an example of the relationship between the hydrogen concentration in exhaust gas and the ammonia concentration in exhaust gas. [Figure 3] FIG. 4 is a diagram illustrating the configuration of a combustion device according to a second embodiment and a boiler equipped with the same. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between the hydrogen concentration in the exhaust gas and the ammonia concentration in the exhaust gas, and a first control value and a second control value. [Figure 5] FIG. 10 is a diagram illustrating the configuration of a combustion device according to a third embodiment and a boiler equipped with the same. [Figure 6] FIG. 1 is a diagram showing the relationship between the hydrogen concentration in the exhaust gas and the ammonia concentration in the exhaust gas under two different combustion conditions. [Figure 7] FIG. 10 is a diagram illustrating the configuration of a combustion device according to a fourth embodiment and a boiler equipped with the same. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings, etc. Note that the drawings shown below, including Fig. 1, are schematic diagrams, and the size and shape of each part are appropriately exaggerated to facilitate understanding. The combustion device of the present invention is a combustion device that burns an ammonia decomposition gas as a fuel gas, and in an embodiment, is applied to a steam boiler that burns an ammonia decomposition gas to generate steam.

[0015] (First embodiment) FIG. 1 is a diagram illustrating the configuration of a combustion device 10 according to a first embodiment and a boiler 1 equipped with the same. The combustion device 10 of this embodiment is a combustion device that burns the ammonia decomposition gas F1 as fuel in a burner 11, and is used in a boiler 1. The combustion device 10 includes a burner 11, a control unit 50, a fuel supply line 210, an air supply line 220, an exhaust gas line 230, etc. The boiler 1 includes the combustion device 10, a boiler body 20, a water supply line 240, and a steam supply line 250. In this specification, the term "line" is a general term for a flow path, a passage, a pipe, etc.

[0016] The boiler body 20 includes a lower header 21, a plurality of water pipes 22, an upper header 23, a combustion chamber B, etc. The boiler body 20 recovers heat from the combustion gas generated by the combustion of fuel in the combustion chamber B, and heats water W1 supplied to the boiler body 20 to generate steam S1. A plurality of water pipes 22 are arranged inside the boiler body 20, extending in the vertical direction. The lower header 21 is disposed at the bottom of the boiler body 20, and is connected to the lower ends of the plurality of water pipes 22. The upper header 23 is disposed at the top of the boiler body 20, and is connected to the upper ends of the plurality of water pipes 22.

[0017] Water W1 is supplied to the lower header 21 from a water supply line 240, which will be described later. The water W1 in the multiple water pipes 22 is heated by combustion gas generated by the combustion of fuel by the burner 11, and generates steam S1. The generated steam S1 flows into the upper header 23. Note that the upper header 23 may be in a state where both the water W1 and the steam S1 exist. Alternatively, the upper header 23 may be configured to be able to supply water to the water pipes 22.

[0018] The burner 11 burns the ammonia decomposition gas F1 as fuel in the combustion chamber B. The burner 11 is connected to a fuel supply line 210 and an air supply line 220, and is supplied with the ammonia decomposition gas F1 as fuel and combustion air A1. The combustion chamber B is a space in which the ammonia decomposition gas F1 and the combustion air A1 are combusted. In this embodiment, the burner 11 is disposed on the upper part of the can body 20. The burner 11 includes a burner body 12 and a wind box 13. A fuel supply line 210 is connected to the burner body 12. An air supply line 220 is connected to the wind box 13. In addition, in this embodiment, for ease of understanding, the burner 11 will be described taking as an example a configuration in which the combustion amount during combustion is one stage (combustion amount 100%).

[0019] The fuel supply line 210 supplies ammonia decomposition gas F1, which is fuel, from an ammonia decomposition device (not shown) to the burner 11. The upstream side of the fuel supply line 210 is connected to the ammonia decomposition device, and the downstream side of the fuel supply line 210 is connected to the burner 11. The ammonia decomposition device is a device that decomposes ammonia supplied from an ammonia supply source (not shown) into ammonia decomposition gas F1 containing hydrogen and nitrogen. This ammonia decomposition gas F1 contains hydrogen, nitrogen, and undecomposed ammonia. The fuel supply line 210 includes, from the upstream side, a main valve 211, a first shutoff valve 213, a flow rate adjustment valve 214, and a second shutoff valve 215.

[0020] The main valve 211 is configured as a manual valve, and opens and closes the flow path of the fuel supply line 210 . The first shutoff valve 213 and the second shutoff valve 215 are configured by electromagnetic valves, and open and close the flow path of the fuel supply line 210 to supply or stop the ammonia decomposition gas F1. The first shutoff valve 213 and the second shutoff valve 215 are electrically connected to the control unit 50, and are controlled based on signals transmitted from the control unit 50. The flow rate control valve 214 is a control valve that adjusts the opening degree of the valve to thereby adjust the flow rate of the ammonia decomposition gas F1 to the burner 11. The flow rate control valve 214 is electrically connected to the control unit 50, and the opening degree of the valve is controlled based on a signal transmitted from the control unit 50. Furthermore, the fuel supply line 210 may be provided with a fuel flow rate sensor (not shown) that detects the flow rate of the ammonia decomposition gas F1 flowing through the fuel supply line 210, and the control unit 50 may be configured to be able to acquire the detection result of the fuel flow rate sensor.

[0021] The air supply line 220 supplies combustion air A1 to the burner 11. In this embodiment, the upstream side of the air supply line 220 is connected to a blower 221, and the downstream side of the air supply line 220 is connected to the burner 11. The air supply line 220 is provided with the blower 221 on the upstream side. The blower 221 supplies combustion air A1 to the burner 11. The blower 221 includes a fan and a motor that rotates the fan. The blower 221 can adjust the rotation speed of the motor by controlling the frequency of the inverter 222, thereby controlling the amount of combustion air A1 supplied. In other words, the inverter 222 is an air amount adjustment unit that can adjust the amount of combustion air A1 supplied to the burner 11. The inverter 222 is electrically connected to the control unit 50 and is controlled based on a signal transmitted from the control unit 50 .

[0022] A damper (not shown) may be provided in the air supply line 220. The damper can adjust the amount of combustion air A1 supplied to the burner 11 by adjusting the opening degree thereof. Specifically, the damper is provided rotatable between a closed state in which the flow path of the air supply line 220 is blocked and an open state in which the damper rotates a predetermined angle (e.g., 90 degrees) from the closed state and opens the flow path of the air supply line 220. The damper is electrically connected to the control unit 50 and is controlled based on a signal transmitted from the control unit 50. Such a damper may be provided and used as the air amount adjusting unit in place of the inverter 222. Also, both the inverter 222 and the damper may be used as the air amount adjusting unit. In addition, the air supply line 220 may be provided with an air flow sensor (not shown) that detects the flow rate of the combustion air A1 flowing through the air supply line 220, and the control unit 50 may be configured to be able to acquire the detection results of the air flow sensor.

[0023] The exhaust gas line 230 discharges exhaust gas E1 generated by burning ammonia decomposition gas F1 and combustion air A1 by the burner 11 to the outside of the can body 20. The upstream side of the exhaust gas line 230 is connected to the upper part of the circumferential surface of the can body 20, and the downstream side of the exhaust gas line 230 is open to the atmosphere. A hydrogen concentration sensor 231 is provided in the exhaust gas line 230. The hydrogen concentration sensor is a hydrogen concentration detection unit that detects the hydrogen concentration in the exhaust gas E1. The hydrogen concentration sensor 231 is electrically connected to the control unit 50, and the control unit 50 can acquire the hydrogen concentration detected by the hydrogen concentration sensor 231. The hydrogen concentration sensor 231 may be provided at the exhaust gas E1 outlet of the can body 20.

[0024] The water supply line 240 supplies water W1 from a water supply source (not shown) to the boiler body 20. The upstream side of the water supply line 240 is connected to the water supply source, and the downstream side of the water supply line 240 is connected to the lower header 21. The water supply line 240 is equipped with a main valve 241. The main valve 241 is configured as a manual valve, and opens and closes the flow path of the water supply line 240.

[0025] The steam supply line 250 supplies steam S1 from the boiler body 20 to a load device (not shown). The upstream side of the steam supply line 250 is connected to the upper header 23 of the boiler body 20, and the downstream side of the steam supply line 250 is connected to the load device. The steam supply line 250 is equipped with a main valve 251. The main valve 251 is configured as a manual valve, and opens and closes the flow path of the steam supply line 250.

[0026] The control unit 50 controls combustion and the like in the combustion device 10. The control unit 50 of this embodiment includes a storage unit 51 and an ammonia emission evaluation unit 52. The control unit 50 is configured with an arithmetic processor such as a PLC (Programmable Logic Controller), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array). The various functions of the control unit 50 are realized, for example, by executing predetermined software (programs) stored in the storage unit 51. The various functions of the control unit 50 may be realized by a combination of hardware and software, or may be realized only by hardware (electronic circuits).

[0027] The storage unit 51 stores various types of setting information. The storage unit 51 also includes a first storage unit 511. The first storage unit 511 stores the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia discharge state. Note that, without being limited to the above example, the first storage unit 511 may be provided in a location different from the storage unit 51, and the control unit 50 may be configured to be able to read information from the first storage unit 511 via communication or the like. The ammonia emission evaluation unit 52 evaluates the ammonia emission state in the exhaust gas E1 based on the detection result of the hydrogen concentration sensor 231 and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state stored in the first memory unit 511.

[0028] Here, the ammonia discharge state includes the ammonia concentration in the exhaust gas E1 corresponding to the hydrogen concentration in the exhaust gas E1, and the stages of ammonia discharge into the exhaust gas E1. The stages of ammonia discharge into the exhaust gas E1 are the process leading to ammonia discharge and the state in which ammonia is discharged, classified according to the range of hydrogen concentration in the exhaust gas E1, etc. In other words, they indicate the degree of allowance or excess of the hydrogen concentration in the exhaust gas E1 at which ammonia discharge occurs (for example, the hydrogen concentration of the ammonia control standard value). In this embodiment, there are four stages of ammonia discharge: Stages A, B, C, and D. Stages A to D will be described in detail later. The evaluation result of the ammonia emission evaluation unit 52 is displayed on, for example, a display unit (not shown) and notified to the operation manager of the combustion device 10 and the boiler 1.

[0029] FIG. 2 is a diagram showing an example of the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia concentration in the exhaust gas E1. In Fig. 2, the vertical axis represents the ammonia concentration in the exhaust gas E1, and the horizontal axis represents the hydrogen concentration in the exhaust gas. Fig. 2 shows an example of the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia concentration in the exhaust gas E1 when the burner 11 is combusted under certain combustion conditions, and shows stages A to D of ammonia emission into the exhaust gas E1 in that relationship. The regions A, B, C, and D indicated by dashed lines in Fig. 2 correspond to stages A, B, C, and D of ammonia emission into the exhaust gas E1. Fig. 2 also shows the control standard value for ammonia in the exhaust gas E1 as 2 ppm. As shown in Figure 2, when ammonia leaks into exhaust gas E1, the increase in the hydrogen concentration in exhaust gas E1 begins earlier than the increase in the ammonia concentration in exhaust gas E1. Furthermore, the dangerous level of hydrogen concentration in exhaust gas E1, 10,000 ppm, is significantly higher than the control standard value of 2 ppm for ammonia concentration. Based on these, by detecting an increase in the hydrogen concentration in the exhaust gas E1, it is possible to predict or detect an increase in the ammonia concentration in the exhaust gas E1 at an early stage, and to suppress leakage of ammonia into the exhaust gas E1. The General High-Pressure Gas Safety Regulations stipulate that the alarm setting value for detecting flammable gas leaks should be 1 / 4 of the lower explosion limit. In this embodiment, the danger level of hydrogen concentration is set to 10,000 ppm, which is 1 / 4 of the lower explosion limit of hydrogen, 40,000 ppm.

[0030] As described above, the first storage unit 511 of this embodiment stores stages A to D shown in FIG. 2 as stages of the discharge of ammonia in the exhaust gas E1. Stage A is a stage in which the hydrogen concentration in the exhaust gas E1 is 0 or so small as to be equal to 0, and the ammonia concentration in the exhaust gas E1 is 0. In stage A, no ammonia is emitted into the exhaust gas E1. In stage B, a small amount of hydrogen is emitted into the exhaust gas E1, but no ammonia is emitted. The dangerous level of hydrogen concentration in the exhaust gas E1 is 10,000 ppm, and in stage B, the hydrogen concentration in the exhaust gas E1 is sufficiently small compared to the dangerous level.

[0031] Stage C is a stage in which both hydrogen and ammonia are emitted into the exhaust gas E1. The hydrogen concentration in the exhaust gas E1 is sufficiently small compared to the dangerous level (10,000 ppm), and the ammonia concentration in the exhaust gas E1 is also increasing, although it is below the control standard value of 2 ppm. This is a stage in which the safety factor is decreasing compared to Stage B. Stage D is a state in which both hydrogen and ammonia are emitted into the exhaust gas E1, and the ammonia concentration in the exhaust gas E1 is equal to or higher than the control standard value of 2 ppm, requiring the issuance of an abnormality alarm and combustion control, etc. In addition, in stages C and D where ammonia is emitted into the exhaust gas E1, the ammonia emission evaluation unit 52 may evaluate the ammonia concentration in the exhaust gas E1 as the ammonia emission state, in addition to or instead of the ammonia emission stage, based on the hydrogen concentration in the exhaust gas E1 and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state stored in the first memory unit 511.

[0032] The evaluation of the state of ammonia discharged from the exhaust gas E1 in the combustion device 10 of this embodiment will be described. In the combustion device 10, the ammonia decomposition gas F1 and the combustion air A1 are supplied to the burner 11, and the burner 11 burns the ammonia decomposition gas F1 as fuel. The exhaust gas E1 generated by the combustion is discharged to the outside of the boiler 1 through the exhaust gas line 230. The hydrogen concentration sensor 231 detects the hydrogen concentration in the exhaust gas E1 and outputs the result to the control unit 50. The ammonia emission evaluation unit 52 acquires the detection result of the hydrogen concentration sensor 231 and reads out the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state from the first storage unit 511. Then, the ammonia emission evaluation unit 52 evaluates the ammonia emission state in the exhaust gas E1 based on the detection result of the hydrogen concentration sensor 231 and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state. Then, the ammonia emission evaluation unit 52 outputs the evaluation result and displays it on, for example, a display unit (not shown). The operation manager of the combustion device 10 can understand the operating state of the combustion device based on the display, and can make records and adjust the operation as necessary.

[0033] Therefore, the combustion device 10 can evaluate the state of ammonia discharge into the exhaust gas E1 (the ammonia concentration in the exhaust gas E1 and the stage of ammonia discharge) by detecting the hydrogen concentration in the exhaust gas. As described above, when ammonia leaks into the exhaust gas E1, the hydrogen concentration in the exhaust gas E1 increases earlier than the ammonia concentration in the exhaust gas E1. Furthermore, the danger level of the hydrogen concentration in the exhaust gas E1 (10,000 ppm) is significantly higher than the control standard value of the ammonia concentration in the exhaust gas E1 (2 ppm). Therefore, by detecting the hydrogen concentration in the exhaust gas E1 and evaluating the ammonia emission state based on this, the combustion device 10 can predict ammonia leakage into the exhaust gas E1 in advance or detect ammonia emission into the exhaust gas E1 earlier and more reliably than when the ammonia concentration in the exhaust gas E1 is detected, thereby suppressing ammonia leakage and enabling safe operation.

[0034] According to the combustion device 10 of this embodiment described above, the following effects can be achieved. (1) The combustion device 10 is a combustion device that burns ammonia decomposition gas, and includes a burner 11 that combusts the ammonia decomposition gas F1, a fuel supply line 210 that supplies the ammonia decomposition gas F1 to the burner 11, an air supply line 220 that supplies combustion air A1 to the burner 11, an exhaust gas line 230 that circulates exhaust gas E1 after combustion of the ammonia decomposition gas F1, a hydrogen concentration sensor 231 that is a hydrogen concentration detection unit that is provided in the exhaust gas line 230 and detects the hydrogen concentration in the exhaust gas E1, and a control unit 50 that controls the combustion device 10. The control unit 50 includes a first memory unit 511 that stores the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state, and an ammonia emission evaluation unit 52 that evaluates the ammonia emission state in the exhaust gas E1 based on the detection result of the hydrogen concentration sensor 231 that is the hydrogen concentration detection unit and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state stored in the first memory unit 511.

[0035] Therefore, the combustion device 10 can evaluate the ammonia emission state in the exhaust gas E1 (the ammonia concentration in the exhaust gas E1 and the stage of ammonia emission into the exhaust gas E1) from the hydrogen concentration in the exhaust gas E1. This allows the combustion device 10 to predict ammonia leakage into the exhaust gas E1 in advance or detect it more quickly and reliably, thereby suppressing ammonia leakage and enabling safe operation.

[0036] (Second embodiment) FIG. 3 is a diagram illustrating the configuration of a combustion device 60 according to the second embodiment and a boiler 1 equipped with the same. The combustion device 60 of the second embodiment is similar to the first embodiment, except that the memory unit 51 further includes a second memory unit 512, and the control unit 50 includes a management value correspondence control unit 53, etc. Therefore, parts that perform the same functions as those of the first embodiment are given the same reference numerals or reference numerals with the same suffixes, and duplicated explanations will be omitted as appropriate. The combustion device 60 of the second embodiment is applicable to the boiler 1, similar to the combustion device 10 of the first embodiment.

[0037] The control unit 50 of the second embodiment includes a storage unit 51 having a first storage unit 511 and a second storage unit 512, a management value correspondence control unit 53, and an air ratio control unit . The second storage unit 512 stores a control value for managing the ammonia discharge state and a control corresponding to the control value in association with each other. The control value for managing the ammonia discharge state is indicated by the hydrogen concentration in the exhaust gas E1. In this embodiment, the second storage unit 512 stores a first control value and a second control value. The first control value and the second control value will be described in detail later. The first storage unit 511 and the second storage unit 512 are not limited to the above example, and may be provided in a location different from the storage unit 51, and the control unit 50 may be configured to be able to read information from each storage unit via communication or the like.

[0038] The control value correspondence control unit 53 controls at least one of stopping combustion in the burner 11, adjusting the air ratio in combustion in the burner 11, and issuing an alarm, based on the control values ​​(in this embodiment, the first control value and the second control value) stored in the second storage unit 512. Specifically, the control value correspondence control unit 53 controls the combustion device 60 based on the detection result of the hydrogen concentration sensor 231 and the control corresponding to the control value stored in the second storage unit 512. The management value correspondence control section 53 may be provided outside the control section 50 and may be configured to be able to send and receive information to and from the control section 50 via communication.

[0039] The air ratio control unit 54 adjusts at least one of the supply amount of combustion air A1 supplied to the burner 11 and the supply amount of ammonia decomposition gas F1 supplied to the burner 11, thereby controlling the air ratio in combustion in the burner 11. Specifically, the air ratio control unit 54 adjusts at least one of the opening degree of the flow rate adjustment valve 214 and the frequency of the inverter 222, thereby controlling the air ratio in combustion in the burner 11.

[0040] FIG. 4 is a diagram showing an example of the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia concentration in the exhaust gas E1, as well as the first control value and the second control value. In Fig. 4, the vertical axis represents the ammonia concentration in the exhaust gas E1, and the horizontal axis represents the hydrogen concentration in the exhaust gas E1. Furthermore, regions A, B, C, and D indicated by dashed lines in Fig. 4 are stages A, B, C, and D of the ammonia discharge into the exhaust gas E1. An example of the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia concentration in the exhaust gas E1 shown in Fig. 4 is the same as that shown in Fig. 2 in the first embodiment. Furthermore, in Fig. 4, the horizontal axis represents the control value for controlling the ammonia discharge state, with the boundary value between stages B and C being the first control value and the boundary value between stages C and D being the second control value.

[0041] The second storage unit 512 stores a first control value and a second control value related to the hydrogen concentration in the exhaust gas E1, and a control corresponding to each control value. The first control value is the hydrogen concentration in the exhaust gas E1 at the time when ammonia starts to be discharged into the exhaust gas E1. In Fig. 4, an example in which the first control value is 1200 ppm will be described. The second control value is a value greater than the first control value, and is the hydrogen concentration in the exhaust gas E1 at the point when the ammonia concentration in the exhaust gas E1 reaches the ammonia control standard value of 2 ppm. In Figure 4, an example where the ammonia concentration is 2400 ppm will be explained.

[0042] When the hydrogen concentration in the flue gas E1 is less than the first control value, the stage of ammonia discharge into the flue gas E1 is stage A and stage B, and no ammonia is discharged into the flue gas E1. When the hydrogen concentration in the flue gas E1 is equal to or greater than the first control value and less than the second control value, the stage of ammonia discharge into the flue gas E1 is stage C, and a trace amount of ammonia is discharged into the flue gas E1. When the hydrogen concentration in the flue gas E1 is equal to or greater than the second control value, the stage of ammonia discharge into the flue gas E1 is stage D, and the ammonia concentration in the flue gas E1 exceeds the control standard value.

[0043] In this embodiment, the ammonia emission evaluation unit 52 acquires the detection result of the hydrogen concentration sensor 231 and reads out the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state from the first storage unit 511. Then, the ammonia emission evaluation unit 52 evaluates the ammonia emission state in the exhaust gas E1 (the ammonia concentration in the exhaust gas E1 and the emission stage of ammonia into the exhaust gas E1) based on the detection result of the hydrogen concentration sensor 231 and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state.

[0044] Furthermore, the control value correspondence control unit 53 acquires the detection result of the hydrogen concentration sensor 231, and reads out the control value that controls the ammonia emission state and the control associated with the control value from the second storage unit 512. Then, the control value correspondence control unit 53 controls the combustion device 60 based on these.

[0045] <When the hydrogen concentration in exhaust gas E1 is below the first control value> If the detection result of the hydrogen concentration sensor 231 acquired by the control value correspondence control unit 53 indicates that the hydrogen concentration in the exhaust gas E1 is less than the first control value, the control value correspondence control unit 53 does not perform control such as issuing an alarm, and the combustion device 60 and boiler 1 continue combustion.

[0046] <When the hydrogen concentration in exhaust gas E1 exceeds the first control value> When the hydrogen concentration in the exhaust gas E1 increases and the detection result of the hydrogen concentration sensor 231 acquired by the control value correspondence control unit 53 indicates that the hydrogen concentration in the exhaust gas E1 exceeds the first control value and is equal to or less than the second control value, the control value correspondence control unit 53 reads out control corresponding to the first control value from the second memory unit 512 and controls the combustion device 60 based on this.

[0047] For example, the control value response control unit 53 issues an instruction to the air ratio control unit 54 to increase the air ratio in combustion in the burner 11. The air ratio control unit 54 adjusts at least one of the supply amount of combustion air A1 supplied to the burner 11 and the supply amount of ammonia decomposition gas F1 supplied to the burner 11, and controls so as to increase the air ratio in combustion in the burner 11. By increasing the air ratio, the combustion state in the burner 11 improves and the ammonia concentration in the exhaust gas E1 decreases. This allows the combustion device 60 to suppress leakage of ammonia into the exhaust gas E1. At this time, the control value response control unit 53 may perform control to issue an alarm or the like indicating that the hydrogen concentration in the exhaust gas E1 is equal to or greater than the first control value and less than the second control value, or may issue a notification (such as displaying on a display unit (not shown) or issuing an alarm) that the air ratio of combustion in the burner 11 has been increased.

[0048] <When the hydrogen concentration in exhaust gas E1 exceeds the second control value> When the hydrogen concentration in the exhaust gas E1 increases and the detection result of the hydrogen concentration sensor 231 acquired by the control value correspondence control unit 53 indicates that the hydrogen concentration in the exhaust gas E1 exceeds the second control value, the control value correspondence control unit 53 reads out control corresponding to the second control value from the second memory unit 512 and controls the combustion device 60 based on this.

[0049] For example, the control value correspondence control unit 53 stops combustion of the burner 11. As a result, if ammonia leaks into the exhaust gas E1 at a concentration exceeding the control standard value, the combustion device 60 can detect this early and stop combustion of the burner 11, thereby preventing ammonia from leaking into the exhaust gas E1. At this time, the control value correspondence control unit 53 may also perform control to issue an alarm or the like indicating that the hydrogen concentration in the exhaust gas E1 is equal to or higher than the second control value. In this way, by setting the boundary value of the ammonia emission stage as the control value, when the ammonia emission stage changes, control can be performed in accordance with the change based on the control value, thereby suppressing the emission of unburned ammonia.

[0050] Furthermore, a value that is lower than the first management value by a predetermined value or more may be set as a lower limit management value, and the second storage unit 512 may store control corresponding to this. <When the hydrogen concentration in exhaust gas E1 falls below the lower limit control value> When the hydrogen concentration in the exhaust gas E1 decreases and the detection result of the hydrogen concentration sensor 231 acquired by the control value correspondence control unit 53 indicates that the hydrogen concentration in the exhaust gas E1 is below the lower limit control value, the control value correspondence control unit 53 reads out control corresponding to the lower limit control value from the second memory unit 512 and controls the combustion device 60 based on this. For example, the control value response control unit 53 issues an instruction to the air ratio control unit 54 to reduce the air ratio in combustion in the burner 11. The air ratio control unit 54 adjusts at least one of the supply amount of combustion air A1 supplied to the burner 11 and the supply amount of ammonia decomposition gas F1 supplied to the burner 11, thereby controlling to reduce the air ratio in combustion in the burner 11. By reducing the air ratio, it is possible to increase the boiler efficiency.

[0051] Therefore, according to this embodiment, in addition to the above effect (1), the following effect can be achieved. (2) The control unit 50 is equipped with a second memory unit 512 that stores control values ​​(first control value and second control value) that are indicated by the hydrogen concentration in the exhaust gas E1 and that control the ammonia emission state, in association with the controls corresponding to the control values. Therefore, the combustion device 60 can be controlled by the control unit 50 based on the management value (such as switching the operation control to stop combustion, or adjusting the combustion state by adjusting the air ratio), thereby preventing the generation of unburned ammonia and preventing ammonia from being emitted outside the system. Furthermore, the control values ​​are not limited to the above examples, but can be set according to various ammonia evaluation conditions such as the level of risk in detecting signs of ammonia leakage into the exhaust gas E1 and leakage judgment, thereby enabling more detailed condition setting for the control of the combustion device 60, and improving the effect of suppressing the generation of unburned ammonia and the effect of suppressing the emission of ammonia outside the system. In addition, by changing the control value according to the operating conditions of the combustion device 60 and the equipment (boiler, etc.) in which the combustion device 60 is used, the effect of suppressing the generation of unburned ammonia and the emission of ammonia outside the system can be further enhanced.

[0052] (3) The combustion device 60 is equipped with a control value correspondence control unit 53 that controls at least one of stopping combustion in the burner 11, adjusting the air ratio in combustion in the burner 11, and issuing an alarm based on control values ​​(first control value, second control value, lower limit control value), and the control value correspondence control unit 53 controls the combustion device based on the detection result of the hydrogen concentration sensor 231, which is a hydrogen concentration detection unit, and control corresponding to the control value that is associated with the control value and stored in the second memory unit 512. Therefore, the control value response control unit 53 stops combustion in the burner 11, issues an alarm, or the like in response to the control value, so that the combustion device 60 can prevent ammonia leakage and operate the combustion device more safely. Furthermore, when an increase in the ammonia concentration in the exhaust gas E1 is predicted, the control value response control unit 53 can suppress the generation of unburned ammonia by increasing the air ratio, thereby enabling the combustion device 60 to prevent ammonia leakage.

[0053] (Third embodiment) FIG. 5 is a diagram illustrating the configuration of a combustion device 70 according to the third embodiment and a boiler 1 equipped with the same. The combustion device 70 of the third embodiment is similar to the combustion device 10 of the first embodiment described above, except that it is different from the first embodiment in that it includes an ammonia concentration sensor 216 and a combustion condition setting unit 55. Therefore, parts having the same functions as those of the first embodiment are given the same reference numerals, and duplicated explanations are omitted as appropriate. The combustion device 70 of the third embodiment can be applied to the boiler 1, just like the combustion device 10 of the first embodiment. The combustion device 70 of this embodiment is provided with an ammonia concentration sensor 216 in the fuel supply line 210, and the control unit 50 is provided with a combustion condition setting unit 55. In this embodiment, the combustion amount of the burner 11 is changeable.

[0054] The burner 11 of this embodiment is capable of combustion at a plurality of combustion stages with different combustion amounts. The combustion amount of the burner 11 may be controlled by step value control, in which the combustion amount changes stepwise according to the step value, or by proportional control, in which the combustion amount changes continuously. The combustion amount of the burner 11 may be controlled by a combustion control unit (not shown) provided in the control unit 50.

[0055] The ammonia concentration sensor 216 is provided in the fuel supply line 210 and detects the ammonia concentration in the ammonia decomposition gas F1. The ammonia concentration sensor 216 is electrically connected to the control unit 50, and the control unit 50 can acquire the detection result of the ammonia concentration sensor 216. FIG. 5 shows an example in which the ammonia concentration sensor 216 is disposed downstream of the second shutoff valve 215, but the present invention is not limited to this. For example, the position at which the ammonia concentration sensor 216 is provided in the fuel supply line 210 may be selected as appropriate, and for example, the ammonia concentration sensor 216 may be disposed upstream of the first shutoff valve 213.

[0056] The combustion condition setting unit 55 is provided in the control unit 50, and sets the combustion conditions of the burner 11, including at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1. The combustion condition setting unit 55 sets the combustion conditions by acquiring the ammonia concentration in the ammonia decomposition gas F1 from the detection result of the ammonia concentration sensor 216. However, without being limited to this, the combustion condition setting unit 55 may acquire the ammonia concentration in the ammonia decomposition gas F1 from an input signal or the like from outside the combustion device 70 and set the combustion conditions. Furthermore, the combustion condition setting unit 55 may obtain the combustion amount of the burner 11 from a combustion amount control unit (not shown) that sets the combustion of the burner 11 and set the combustion amount, or may obtain the combustion amount from an input signal or the like from outside the combustion device 10 and set the combustion amount. In this embodiment, an example is shown in which the combustion condition setting unit 55 is provided in the control unit 50, but this is not limited to this, and the combustion condition setting unit 55 may be provided outside the control unit 50 and be capable of sending and receiving information to and from the control unit 50 via communication.

[0057] The ammonia concentration in the exhaust gas E1 varies depending on the ammonia concentration in the ammonia decomposition gas F1 and the combustion amount of the burner 11. Fig. 6 is a graph showing the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia concentration in the exhaust gas E1 under two different combustion conditions. In Fig. 6, the vertical axis represents the ammonia concentration in the exhaust gas E1, and the horizontal axis represents the hydrogen concentration in the exhaust gas E1. 6 shows the hydrogen concentration and ammonia concentration in exhaust gas E1 under two different combustion conditions, combustion condition 1 and combustion condition 2. The relationship between the hydrogen concentration and ammonia concentration in exhaust gas E1 under combustion condition 1 corresponds to one example of the relationship between the hydrogen concentration and ammonia concentration in exhaust gas E1 shown in FIG. 2 in the first embodiment. Furthermore, combustion condition 2 shown in FIG. 2 represents, as an example, a combustion condition in which the ammonia concentration in ammonia decomposition gas F1 is higher than that under combustion condition 1.

[0058] As shown in Figure 6, if the combustion conditions are different, the range of the hydrogen concentration in the exhaust gas E1 corresponding to the ammonia emission stage will also differ. Accordingly, the hydrogen concentration in the exhaust gas E1 at which ammonia begins to be emitted into the exhaust gas E1 (i.e., the first control value in the second embodiment) and the hydrogen concentration in the exhaust gas E1 at which the ammonia concentration in the exhaust gas E1 becomes equal to or greater than the control standard value (i.e., the second control value in the second embodiment) also differ. Under combustion condition 1, the first control value is 1200 ppm and the second control value is 2400 ppm, whereas under combustion condition 2, the first control value is 50 ppm and the second control value is 150 ppm.

[0059] Therefore, the first memory unit 511 of this embodiment stores the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state in the exhaust gas E1 in further association with the setting results set by the combustion condition setting unit 55 (i.e., combustion conditions including at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1).

[0060] In addition, the ammonia emission evaluation unit 52 of this embodiment evaluates the ammonia emission state based on the detection result of the hydrogen concentration sensor 231, the setting result of the combustion condition setting unit 55, and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state, which is further correlated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1 stored in the first memory unit 511.

[0061] The combustion condition setting unit 55 sets combustion conditions and outputs them to the ammonia emission evaluation unit 52. The ammonia emission evaluation unit 52 acquires the detection result of the hydrogen concentration sensor 231 and the setting result of the combustion condition setting unit 55, and reads from the first storage unit 511 the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state, which relationship is further associated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1. Based on these, the ammonia emission evaluation unit 52 evaluates the state of ammonia emission in the exhaust gas E1.

[0062] By adopting such a configuration, the ammonia emission evaluation unit 52 can more accurately evaluate the ammonia emission state according to combustion conditions such as the combustion amount and the ammonia concentration in the ammonia decomposition gas. Furthermore, even when the combustion conditions of the combustion device 10 change due to a change in the combustion amount of the burner 11 or a change in the ammonia concentration in the ammonia decomposition gas F1 caused by the operating status of the ammonia decomposition gas device, the ammonia emission evaluation unit 52 can more accurately evaluate the ammonia emission state according to the combustion conditions. Therefore, leakage of ammonia into the exhaust gas E1 can be suppressed.

[0063] According to the present embodiment described above, in addition to the above effects (1) to (3), the following effects can be achieved. (4) The combustion device 70 includes a combustion condition setting unit 55 that sets combustion conditions including at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1, and the first memory unit 511 stores the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state, further correlating it with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1, and the ammonia emission evaluation unit evaluates the ammonia emission state based on the detection result of the hydrogen concentration sensor 231, which is a hydrogen concentration detection unit, the setting result of the combustion condition setting unit 55, and the relationship between the hydrogen concentration in the exhaust gas E1 and the ammonia emission state, which is stored in the first memory unit 511 and further correlated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas F1. Therefore, the ammonia emission evaluation unit 52 can more accurately evaluate the ammonia emission state according to the combustion conditions.

[0064] (Fourth embodiment) FIG. 7 is a diagram illustrating the configuration of a combustion device 80 according to the fourth embodiment and a boiler 1 equipped with the same. The combustion device 80 of the fourth embodiment is similar in configuration to the combustion device 10 shown in the first embodiment, except that the control unit 50 includes an exhaust gas ammonia generation threshold evaluation unit 56. Therefore, parts having the same functions as those of the first embodiment described above are denoted by the same reference numerals or with the same reference numerals at the end, and duplicated explanations will be omitted as appropriate. The combustion device 80 of the fourth embodiment can be applied to the boiler 1, just like the combustion device 10 of the first embodiment.

[0065] In the combustion device 80 of this embodiment, the control unit 50 includes the exhaust gas ammonia generation threshold evaluation unit 56, as described above. The exhaust gas ammonia generation threshold evaluation unit 56 temporarily reduces the air ratio using the air ratio control unit 54 until the ammonia emission evaluation unit 52 evaluates that the predetermined ammonia emission state is reached, and evaluates the air ratio that will result in the predetermined ammonia emission state. Note that, although the present embodiment shows an example in which the exhaust gas ammonia generation threshold evaluation unit 56 is provided in the control unit 50, the present invention is not limited to this, and the exhaust gas ammonia generation threshold evaluation unit 56 may be provided outside the control unit 50 and be capable of communicating with the control unit 50.

[0066] When the combustion device 80 is burning, the exhaust gas ammonia generation threshold evaluation unit 56 temporarily reduces the air ratio using the air ratio control unit 54 until the ammonia emission evaluation unit 52 evaluates that the ammonia emission state into the exhaust gas E1 is in a predetermined state. The reduction in the air ratio causes unburned ammonia and hydrogen to leak into the exhaust gas E1, increasing their concentrations. In this embodiment, the exhaust gas ammonia generation threshold evaluation unit 56 reduces the air ratio until the ammonia emission evaluation unit 52 evaluates the state of ammonia emission into the exhaust gas E1 as a state in which the ammonia concentration is greater than 0 ppm and the emission stage is stage C. When the ammonia emission evaluation unit 52 evaluates the ammonia emission state as the above-mentioned state, the exhaust gas ammonia generation threshold evaluation unit 56 acquires this and evaluates the air ratio at this time as the threshold at which the ammonia emission state becomes a predetermined state (i.e., the threshold at which ammonia is generated in the exhaust gas E1).

[0067] Therefore, according to this embodiment, the exhaust gas ammonia generation threshold evaluation unit 56 can accurately evaluate the air ratio at which the combustion device 80 starts to emit ammonia into the exhaust gas E1. Furthermore, the combustion device 80 can quantitatively evaluate the risk of ammonia leaking into the exhaust gas E1 using the air ratio, and based on this, can perform stable combustion and suppress ammonia leakage. Furthermore, the combustion device 80 can temporarily change the air ratio from the original appropriate air ratio to create a combustion state that is more likely to generate ammonia (i.e., the hydrogen concentration in the exhaust gas E1 increases), thereby determining to what extent the combustion state must change to cause ammonia to leak into the exhaust gas E1 or to create a state where there is a high risk of leakage, thereby conducting a risk assessment (a so-called "self-check").

[0068] As described above, according to this embodiment, in addition to the above effects (1) to (4), the following effects can be achieved. (5) The control unit 50 includes an air ratio control unit 54 that adjusts at least one of the amount of combustion air A1 supplied to the burner 11 and the amount of ammonia decomposition gas F1 supplied to the burner 11, thereby controlling the air ratio in combustion in the burner 11, and an exhaust gas ammonia generation threshold evaluation unit 56 that temporarily lowers the air ratio using the air ratio control unit 54 until the ammonia emission evaluation unit 52 evaluates that a predetermined ammonia emission state is reached, and evaluates the air ratio that results in the predetermined ammonia emission state.

[0069] Therefore, the combustion device 80 can evaluate the air ratio at which a predetermined ammonia emission state is achieved using the exhaust gas ammonia generation threshold evaluation unit 56, and therefore can accurately evaluate the air ratio at which ammonia leaks depending on the combustion device. Furthermore, this allows the combustion device 80 to perform a so-called "self-check" by temporarily changing the air ratio from the original appropriate air ratio to create a combustion state that is more likely to generate ammonia (i.e., the hydrogen concentration increases), thereby checking to what extent the combustion state needs to change to cause ammonia leakage or to determine a state that creates a high risk of leakage, and conducting a risk assessment. Furthermore, by including the air ratio control unit 54 and the exhaust gas ammonia generation threshold evaluation unit 56, the combustion device 80 can quantitatively evaluate the risk of ammonia leakage into the exhaust gas E1 based on the air ratio, thereby enabling stable combustion and suppressing ammonia leakage outside the system.

[0070] (Variations) The present invention is not limited to the above-described embodiments, and various modifications and variations are possible, and these are also within the scope of the present invention. In the third embodiment, the control unit 50 may be configured to include a second memory unit 512 and a control value correspondence control unit 53, where the second memory unit 512 stores the first control value and the second control value under combustion condition 2 and the control corresponding to these control values, and the control value correspondence control unit 53 may be configured to control the combustion device based on the detection result of the hydrogen concentration sensor 231 and the control stored in the second memory unit 512 in association with each control value corresponding to each combustion condition.

[0071] In the second embodiment, the second memory unit 512 has been described as storing a first management value and a second management value, but this is not limited to this, and the number of management values ​​stored in the second memory unit 512 may be one, or three or more. For example, the second control value of the second embodiment may be set as a third control value, with the second control value being set between the first and third control values, and the control value correspondence control unit 53 may issue an alarm when the hydrogen concentration in the exhaust gas E1 exceeds the second control value, and when the ammonia emission state progresses and the hydrogen concentration in the exhaust gas E1 exceeds the third control value, the combustion device 60 may be stopped. In this way, by increasing the control value of the hydrogen concentration in the exhaust gas E1, even more flexible control can be performed.

[0072] The present invention is not limited to the above-described embodiments, but may be combined with other embodiments as desired.

[0073] The present invention promotes the use of ammonia as a fuel, which does not emit carbon dioxide, and can therefore contribute, for example, to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), which is to "ensure access to affordable, reliable, sustainable and modern energy." [Explanation of symbols]

[0074] 1 boiler 10,60,70,80 Combustion equipment 11 Burner 20 can body 50 control section 51 Storage section 511 1st memory section 512 2nd memory section 52 Ammonia Emissions Evaluation Section 53 Control value response control section 54 Air ratio control unit 55 Combustion condition setting section 56 Ammonia generation threshold evaluation unit in exhaust gas 210 Fuel supply line 220 Air supply line 230 Exhaust gas line 231 Hydrogen concentration sensor

Claims

1. A combustion device for burning ammonia decomposition gas, a burner that burns the ammonia decomposition gas; a fuel supply line for supplying the ammonia decomposition gas to the burner; an air supply line for supplying combustion air to the burner; an exhaust gas line through which exhaust gas obtained after combustion of the ammonia decomposition gas flows; a hydrogen concentration detector provided in the exhaust gas line and configured to detect a hydrogen concentration in the exhaust gas; a control unit that controls the combustion device; Equipped with The control unit a first storage unit that stores a relationship between the hydrogen concentration in the exhaust gas and the ammonia discharge state; an ammonia emission evaluation unit that evaluates a state of ammonia emission in the exhaust gas based on a detection result of the hydrogen concentration detection unit and the relationship between the hydrogen concentration in the exhaust gas and ammonia emission state stored in the first storage unit; A combustion device comprising:

2. a combustion condition setting unit that sets combustion conditions including at least one of a combustion amount and an ammonia concentration in the ammonia decomposition gas; the first storage unit stores a relationship between the hydrogen concentration in the exhaust gas and the ammonia discharge state in such a manner that the relationship is further associated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas; The ammonia emission evaluation unit a detection result of the hydrogen concentration detection unit; The setting result of the combustion condition setting unit; a relationship between a hydrogen concentration in the exhaust gas and an ammonia discharge state, the relationship being further correlated with at least one of the combustion amount and the ammonia concentration in the ammonia decomposition gas stored in the first storage unit; Evaluate the ammonia emission status based on The combustion device of claim 1 .

3. the control unit includes a second storage unit that stores a control value that is indicated by the hydrogen concentration in the exhaust gas and that controls an ammonia discharge state, in association with a control corresponding to the control value. The combustion device of claim 1 .

4. a control value response control unit that controls at least one of stopping combustion in the burner, adjusting the air ratio in combustion in the burner, and issuing an alarm based on the control value; The management value correspondence control unit a detection result of the hydrogen concentration detection unit; Control corresponding to the management value stored in the second storage unit; and controlling the combustion device based on the The combustion device according to claim 3.

5. The control unit an air ratio control unit that adjusts at least one of the amount of combustion air supplied to the burner and the amount of ammonia decomposition gas supplied to the burner to control the air ratio in combustion in the burner; an exhaust gas ammonia generation threshold evaluation unit that temporarily reduces the air ratio by the air ratio control unit until the ammonia emission evaluation unit evaluates that the ammonia emission state is a predetermined state, and evaluates the air ratio that will result in the predetermined ammonia emission state; Equipped with The combustion device of claim 1 .

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