Combustion device

Abstract

To provide a combustion device capable of timely grasping an ammonia concentration in an ammonia decomposition gas supplied as fuel in order to perform suitable combustion control.SOLUTION: A combustion device includes: a burner to combust an ammonia decomposition gas; a fuel supply line to supply the ammonia decomposition gas; an air supply line to supply combustion air; an exhaust gas line through which exhaust gas generated by combustion of the ammonia decomposition gas and the combustion air flows; an NOx concentration detection unit to detect NOx concentration in the exhaust gas; and a control unit. The control unit includes: a first storage unit to store a relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas; and an ammonia concentration calculation unit to calculate the ammonia concentration in the ammonia decomposition gas based on a detection result of the NOx concentration detection unit and the relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas 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 become widespread. Among combustion devices that use ammonia fuel, there are some that decompose the ammonia fuel into nitrogen and hydrogen to produce ammonia decomposition gas, which is then mixed with combustion air and burned (for example, Patent Documents 1 and 2). It is known that when ammonia decomposition gas is burned as fuel, the NOx concentration in the exhaust gas resulting from the combustion of the ammonia decomposition gas increases as the ammonia concentration in the ammonia decomposition gas increases (see, for example, Patent Document 3). [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 [Patent Document 3] Japanese Patent Application Publication No. 2018-096616 Summary of the Invention [Problem to be solved by the invention]

[0004] In combustion equipment such as industrial boilers that burn ammonia decomposition gas, there is a range in which the ammonia concentration in the ammonia decomposition gas can maintain a suitable combustion state for each device, and if the range is exceeded, there is a risk of abnormal combustion or an increase in harmful substances such as NOx and unburned ammonia.It is also known that the combustion conditions for maintaining a suitable combustion state vary depending on the ammonia concentration in the ammonia decomposition gas.Therefore, it is important to understand the ammonia concentration in the ammonia decomposition gas in the combustion equipment.

[0005] As a method for determining the ammonia concentration in the ammonia decomposition gas, for example, a method of determining the ammonia concentration in the ammonia decomposition gas by measuring the fuel composition using a gas analyzer or the like is known. However, this method is not preferable because the measuring equipment is expensive and leads to an increase in the production cost of the combustion device.

[0006] Generally, combustion equipment such as industrial boilers and ammonia decomposition equipment are operated independently, and their operating conditions do not necessarily coincide. Furthermore, a cushion tank or the like may be installed to store ammonia decomposition gas, which creates a time lag between the generation of ammonia decomposition gas in the ammonia decomposition equipment and the arrival of the ammonia decomposition gas at the combustion equipment. Therefore, there are problems with using the ammonia concentration in the ammonia decomposition gas obtained by the ammonia decomposition equipment to control the combustion equipment. In addition, in industrial boilers, the combustion amount fluctuates depending on the heat demand (load) on the demand side. Therefore, the amount of NOx and other emissions varies depending on the combustion conditions, combustion amount, etc., in addition to the ammonia concentration in the ammonia cracked gas supplied as fuel. However, no method has been provided to date for determining the ammonia concentration in ammonia cracking gas that can respond in a timely manner to fluctuations in combustion conditions and combustion amount and that is applicable to combustion equipment such as industrial boilers, nor has any method been provided to date for controlling combustion equipment based on the determined ammonia concentration.

[0007] In view of the above, there is a demand for a combustion device that can timely grasp the ammonia concentration in the ammonia cracked gas supplied as fuel in order to perform suitable combustion control.

[0008] An object of the present invention is to provide a combustion apparatus that can timely grasp the ammonia concentration in ammonia cracked gas supplied as fuel in order to perform suitable combustion control. [Means for solving the problem]

[0009] The present invention solves the above problems by the following means.

[0010] The combustion device of the present invention includes a burner that burns 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 generated by combustion of the ammonia decomposition gas and the combustion air flows, a NOx concentration detection unit that detects the NOx concentration in the exhaust gas, and a control unit, wherein the control unit includes a first memory unit that stores the relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas, and an ammonia concentration calculation unit that calculates the ammonia concentration in the ammonia decomposition gas based on the detection result of the NOx concentration detection unit and the relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas stored in the first memory unit.

[0011] Furthermore, it is preferable that the control unit includes a combustion condition setting unit that sets combustion conditions including at least one of a combustion amount of the combustion device and an air ratio in combustion, the first storage unit stores a relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas in further association with the combustion conditions, and the ammonia concentration calculation unit acquires the detection result of the NOx concentration detection unit and the setting result of the combustion condition setting unit, and calculates the ammonia concentration in the ammonia decomposition gas based on the detection result, the setting result, and the relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas that is stored in the first storage unit and further associated with the combustion conditions.

[0012] It is also preferable that the combustion device includes an oxygen concentration detection unit that detects the oxygen concentration in the exhaust gas, the control unit includes an air ratio calculation unit that calculates an air ratio based on the detection result of the oxygen concentration detection unit, and the combustion condition setting unit acquires the calculation result of the air ratio calculation unit and sets the air ratio as the combustion condition.

[0013] Furthermore, it is preferable that the control unit includes a second storage unit that stores ammonia management information that associates a reference value of the ammonia concentration in the ammonia decomposition gas supplied to the combustion device with control related to the reference value, and controls the operation of the combustion device based on the calculation result of the ammonia concentration calculation unit and the ammonia management information stored in the second storage unit.

[0014] Furthermore, it is preferable that the ammonia management information includes at least one of: a first reference value, which is an ammonia concentration that serves as a criterion for reporting an abnormality in the ammonia concentration in the ammonia decomposition gas, associated with control for reporting an abnormality in the ammonia concentration in the ammonia decomposition gas; or a second reference value, which is an ammonia concentration that stops combustion in the combustion device due to an abnormality in the ammonia concentration in the ammonia decomposition gas, associated with control for stopping combustion in the combustion device. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a combustion device that can timely grasp the ammonia concentration in the ammonia cracked gas supplied as fuel in order to perform suitable combustion control. [Brief explanation of the drawings]

[0016] [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. 3 is a diagram showing an example of the relationship between the ammonia concentration in an ammonia decomposition gas and the NOx 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. 2 is a graph showing the relationship between the air ratio, the NOx concentration in the exhaust gas, and the ammonia concentration in the ammonia decomposition gas. [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. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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.

[0018] (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 applied to the 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, a steam supply line 250, etc. In this specification, the term "line" is a general term for a flow path, a passage, a pipe, etc.

[0019] 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.

[0020] 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 tubes 22 is heated by combustion gas generated by the combustion of fuel ejected from 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 tubes 22.

[0021] The burner 11 is connected to a fuel supply line 210 and an air supply line 220, and ejects into the combustion chamber B 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.

[0022] The burner 11 may be configured to have a single combustion amount during combustion (100% combustion amount), or may be configured to be capable of combustion in multiple combustion stages with different combustion amounts. When a burner is configured to be capable of combustion in multiple combustion stages, the combustion amount of the burner 11 may be controlled by step value control so that the combustion amount changes stepwise according to the step value, or by proportional control so that the combustion amount changes continuously. The control of the combustion amount of the burner 11 may be performed by a combustion control unit (not shown) provided in the control unit 50. 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%).

[0023] 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 fuel flow rate sensor 212, a first shutoff valve 213, a flow rate adjustment valve 214, and a second shutoff valve 215.

[0024] The main valve 211 is configured as a manual valve, and opens and closes the flow path of the fuel supply line 210 . The fuel flow rate sensor 212 detects the flow rate of the ammonia decomposition gas F1 flowing through the fuel supply line 210. The fuel flow rate sensor 212 is electrically connected to the control unit 50, and the control unit 50 can acquire the flow rate of the ammonia decomposition gas F1. 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.

[0025] 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 is connected to the burner 11. The air supply line 220 includes, from the upstream side, the blower 221 and an air flow sensor 223. 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. 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 .

[0026] The air flow sensor 223 detects the flow rate of the combustion air A1 flowing through the air supply line 220. The air flow sensor 223 is electrically connected to the control unit 50, and the control unit 50 can acquire the detection result of the air flow sensor 223.

[0027] A damper (not shown) may be provided on the air supply line 220, for example, downstream of the air flow sensor 223. The damper can adjust the amount of combustion air A1 supplied to the burner 11 by adjusting its opening. 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.

[0028] The exhaust gas line 230 discharges, as exhaust gas E1, combustion gas that is generated by combustion of the ammonia decomposition gas F1 and the combustion air A1 and whose heat is recovered by the water W1 in the plurality of water tubes 22, 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.

[0029] The NOx concentration sensor 231 is a NOx concentration detection unit that detects the NOx concentration in the exhaust gas E1. The NOx concentration sensor 231 is electrically connected to the control unit 50, and the control unit 50 can acquire the detection result of the NOx concentration sensor 231. In the present embodiment, an example in which the NOx concentration sensor 231 is provided in the exhaust gas line L230 will be described, but this is not limiting, and the NOx concentration sensor 231 may be provided at an exhaust gas E1 outlet of the can body 20 or in a flow path of the exhaust gas E1 (combustion gas) inside the can body 20.

[0030] 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.

[0031] 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.

[0032] The control unit 50 controls the combustion in the combustion device 10. The control unit 50 includes a storage unit 51 and an ammonia concentration calculation 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).

[0033] The storage unit 51 stores various setting information. The storage unit 51 also includes a first storage unit 511 that stores the relationship between the ammonia concentration in the ammonia cracked gas F1 and the NOx concentration in the exhaust gas E1. However, the present invention is not limited to this, and 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.

[0034] The ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result of the NOx concentration sensor 231, which is a NOx concentration detection unit, and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, which is stored in the first memory unit 511.

[0035] FIG. 2 is a diagram showing an example of the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1. As shown in Figure 2, as the NOx concentration in the exhaust gas E1 increases, the ammonia concentration in the ammonia decomposition gas F1 also increases. Furthermore, the relationship between the NOx concentration in the exhaust gas E1 and the ammonia concentration in the ammonia decomposition gas F1 differs depending on the individual combustion device, just as it differs between combustion device A and combustion device B.

[0036] Therefore, the first storage unit 511 stores the relationship between the NOx concentration in the exhaust gas E1 and the ammonia concentration in the ammonia decomposition gas F1 according to the combustion device 10. The ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the relationship between the NOx concentration in the exhaust gas E1 and the ammonia concentration in the ammonia decomposition gas F1 in the combustion device 10, which is stored in the first storage unit 511. The first storage unit 511 may store the relationship between the NOx concentration in the exhaust gas E1 and the ammonia concentration in the ammonia decomposition gas F1 as a mathematical formula or, for example, as a data table.

[0037] The calculation of the ammonia concentration in the combustion device 10 of this embodiment will be described. In the combustion device 10, the ammonia decomposition gas F1 and 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 produced by the combustion is discharged through an exhaust gas line 230. The NOx concentration sensor 231 detects the NOx concentration in the exhaust gas E1 and outputs the result to the control unit .

[0038] The ammonia concentration calculation unit 52 acquires the detection result of the NOx concentration sensor 231 and reads out the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 from the first storage unit 511. Then, the ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result of the NOx concentration sensor 231 and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 read out from the first storage unit 511. The ammonia concentration calculation unit 52 may output the calculation result to, for example, a display unit (not shown), which may then display the result. This allows the operator of the combustion device 10 and the boiler 1 equipped with the combustion device 10 to understand the ammonia concentration in the ammonia decomposition gas F1 and to operate the device so as to suppress NOx, unburned ammonia, and the like in the exhaust gas E1. Furthermore, the calculation result of the ammonia concentration calculation unit 52 may be acquired by a combustion control unit (not shown) or the like provided in the control unit 50, and the combustion conditions or the like for combustion in the burner 11 may be controlled. This allows combustion in the burner 11 to be suitable according to the ammonia concentration, and makes it possible to suppress NOx, unburned ammonia, and the like in the exhaust gas E1.

[0039] According to this embodiment, as described above, the ammonia concentration calculation unit 52 can calculate the ammonia concentration in the ammonia decomposition gas F1 from the NOx concentration in the exhaust gas E1. This allows the combustion device 10 to timely grasp the ammonia concentration in the ammonia decomposition gas F1 supplied as fuel, thereby enabling appropriate combustion control. The combustion conditions (combustion amount, air ratio, etc.) for maintaining a suitable combustion state vary depending on the ammonia concentration in the ammonia decomposition gas F1, and deviation from the suitable combustion state may result in abnormal combustion or an increase in harmful substances such as NOx and unburned ammonia in the exhaust gas E1. However, according to this embodiment, the combustion device 10 can timely grasp the ammonia concentration in the ammonia decomposition gas F1, and based on this, can control the combustion conditions, etc. to maintain a suitable combustion state and suppress the NOx concentration, etc.

[0040] Furthermore, the ammonia concentration in the ammonia decomposition gas F1 that can maintain a suitable combustion state varies depending on the combustion device. According to this embodiment, even if a plurality of combustion devices 10 are arranged and used, in each combustion device 10, the ammonia concentration calculation unit 52 can calculate the ammonia concentration in the ammonia decomposition gas F1 supplied to each combustion device 10 based on the NOx concentration in the exhaust gas E1 detected by the NOx concentration sensor 231 and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 read from the first memory unit 511. This makes it possible to timely grasp the ammonia concentration in the ammonia decomposition gas F1 supplied to each combustion device 10, and to perform combustion control suitable for each combustion device 10.

[0041] The combustion device 10 of this embodiment described above provides the following effects. (1) The combustion device 10 includes a burner 11 that combusts 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 through which exhaust gas E1 generated by combustion of the ammonia decomposition gas F1 and the combustion air A1 flows, a NOx concentration sensor 231 that is a NOx concentration detection unit that detects the NOx concentration in the exhaust gas E1, and a control unit 50 that controls the operation of the combustion device. The control unit 50 includes a first memory unit 511 that stores the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, and an ammonia concentration calculation unit 52 that calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result of the NOx concentration sensor 231 and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 stored in the first memory unit 511.

[0042] Therefore, the combustion device 10 can calculate the ammonia concentration in the ammonia decomposition gas F1 from the NOx concentration in the exhaust gas E1 using the ammonia concentration calculation unit 52. This allows the operator of the combustion device 10 and the boiler 1 equipped with the same to understand the ammonia concentration in the ammonia decomposition gas F1 and operate the combustion device 10 so as to suppress NOx, unburned ammonia, etc. in the exhaust gas E1 according to the ammonia concentration. Therefore, the combustion device 10 can control combustion so as to maintain suitable combustion. Furthermore, even if a plurality of combustion devices 10 are installed, it is possible to calculate the ammonia concentration in the ammonia cracked gas F1 supplied to each combustion device 10 by individually detecting the NOx concentration in the exhaust gas E1 from each combustion device 10. This allows suitable combustion control to be performed for each combustion device 10, and the combustion devices 10 and the boiler 1 equipped with them can be operated safely.

[0043] (Second embodiment) The combustion device 60 of the second embodiment is similar to the combustion device 10 of the first embodiment, except that the control unit 50 includes a combustion condition setting unit 53 and an air ratio calculation unit 54, and an oxygen concentration sensor 232 is provided in the exhaust gas line 230. Therefore, parts that perform the same functions as those in the first embodiment described above are given the same reference numerals or have the same reference numerals at the end, and redundant explanations will be omitted as appropriate.

[0044] 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. In the combustion device 60 of the second embodiment, the control unit 50 includes a combustion condition setting unit 53 and an air ratio calculation unit 54 in addition to a memory unit 51 and an ammonia concentration calculation unit 52, and the exhaust gas line 230 is provided with an oxygen concentration sensor 232 in addition to an NOx concentration sensor 231. The combustion device 60 of the second embodiment is applied to the boiler 1, similarly to the combustion device 10 of the first embodiment.

[0045] The oxygen concentration sensor 232 is an oxygen concentration detection unit that detects the oxygen concentration in the exhaust gas E1. The oxygen concentration sensor 232 is electrically connected to the control unit 50, and the control unit 50 can acquire the detection result of the oxygen concentration sensor 232. 3, the present embodiment illustrates an example in which the oxygen concentration sensor 232 is disposed downstream of the NOx concentration sensor 231 in the exhaust gas line L230, but the location at which the oxygen concentration sensor 232 is disposed may be selected as appropriate. For example, the oxygen concentration sensor 232 may be disposed at the same position as the NOx concentration sensor 231 in the exhaust gas line 230, or may be disposed upstream of the NOx concentration sensor 231, or may be disposed at the exhaust gas E1 outlet of the can body 20 or in the flow path of the exhaust gas E1 (combustion gas) inside the can body 20. Furthermore, the NOx concentration sensor 231 and the oxygen concentration sensor 232 may not be disposed separately, but may be detected by the same detector.

[0046] The air ratio calculation unit 54 is provided in the control unit 50 and calculates the air ratio based on the detection result of the oxygen concentration sensor 232. The memory unit 51 stores a formula for calculating the air ratio from the exhaust gas oxygen concentration, and the air ratio calculation unit 54 calculates the air ratio using the detection result of the oxygen concentration sensor 232 acquired and the formula read from the memory unit 51.

[0047] The combustion condition setting unit 53 is provided in the control unit 50 and sets combustion conditions including at least one of the combustion amount of the combustion device 60 and the air ratio in combustion. In this embodiment, an example will be described in which the air ratio is set as the combustion condition based on the calculation result of the air ratio calculation unit 54. The combustion condition setting unit 53 is not limited to the above example, and may set the combustion amount of the burner 11 as the combustion condition, or may set both the combustion amount and the air ratio as the combustion conditions. When setting the combustion amount of the burner 11 as the combustion condition, the combustion condition setting unit 53 may calculate and set the combustion amount of the burner 11 based on the detection result of the fuel flow rate sensor 212, for example. Furthermore, the combustion condition setting unit 53 may set the combustion amount of the burner 11 and the air ratio in combustion as combustion conditions based on a signal or the like input from outside the combustion device 60. For example, the combustion amount and the air ratio input by an input device or the like (not shown) may be set as combustion conditions.

[0048] The first storage unit 511 of this embodiment stores the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, further associating it with the combustion conditions for combustion in the burner 11. Examples of the combustion conditions include an air ratio and a combustion amount. In this embodiment, an example will be described in which the first storage unit 511 stores the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, further associating it with the air ratio, which is a combustion condition.

[0049] If the combustion conditions in the combustion of the burner 11, such as the combustion amount and the air ratio, are different, the NOx concentration in the exhaust gas E1 will be different even if the ammonia concentration in the ammonia decomposition gas F1 is the same. FIG. 4 is a diagram showing the relationship between the air ratio, the NOx concentration in the exhaust gas E1, and the ammonia concentration in the ammonia decomposition gas F1. As shown in FIG. 4, when the air ratio, which is one of the combustion conditions, is different, the ammonia concentration in the ammonia decomposition gas F1 is different even if the NOx concentration in the exhaust gas E1 is the same. Therefore, in this embodiment, the first storage unit 511 stores the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 in association with the air ratio, which is a combustion condition, thereby enabling the ammonia concentration calculation unit 52 to more accurately calculate the ammonia concentration in the ammonia decomposition gas F1. The first memory unit 511 of this embodiment may store the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 at each air ratio as a calculation formula or as table data.

[0050] The calculation of the ammonia concentration in the combustion device 60 of this embodiment will be described below. In the combustion device 60, the ammonia decomposition gas F1 and combustion air A1 are supplied to the burner 11, and the burner 11 burns the ammonia decomposition gas F1 as fuel. Exhaust gas E1 produced by combustion is discharged through an exhaust gas line 230. An NOx concentration sensor 231 detects the NOx concentration in the exhaust gas E1 and outputs the result to the control unit 50, and an oxygen concentration sensor 232 detects the oxygen concentration in the exhaust gas E1 and outputs the result to the control unit 50. The air ratio calculation unit 54 acquires the detection result of the oxygen concentration sensor 232, and calculates the air ratio based on this. The combustion condition setting unit 53 acquires the calculation results of the air ratio calculation unit, and sets the air ratio that is the combustion condition based on these.

[0051] The ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result of the NOx concentration sensor 231, the setting result of the combustion condition setting unit 53, and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, which is further associated with the combustion conditions (air ratio in this embodiment) read from the first memory unit 511.

[0052] The ammonia concentration calculation unit 52 may output the calculation result to, for example, a display unit (not shown), which may then display the result. This allows the operator of the combustion device 60 and the boiler 1 equipped with the combustion device 60 to understand the ammonia concentration in the ammonia decomposition gas F1 and to operate the device so as to suppress NOx, unburned ammonia, and the like in the exhaust gas E1. Furthermore, the calculation result of the ammonia concentration calculation unit 52 may be acquired by a combustion control unit (not shown) or the like provided in the control unit 50, and the combustion conditions or the like for combustion in the burner 11 may be controlled. This allows combustion in the burner 11 to be optimized according to the ammonia concentration, and makes it possible to suppress harmful substances such as NOx and unburned ammonia in the exhaust gas E1.

[0053] According to this embodiment, the ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, which relationship is further correlated with the combustion conditions (air ratio in this embodiment), so that the accuracy of the ammonia concentration calculation can be improved. For example, when the air ratio in the combustion in the combustion device 60 fluctuates due to some external factor or the like, the air ratio calculation unit 54 calculates the air ratio based on the oxygen concentration detected by the oxygen concentration sensor 232, so that the ammonia concentration calculation unit 52 can calculate the ammonia concentration with higher accuracy. Therefore, according to this embodiment, the combustion device 60 can grasp the ammonia concentration in the ammonia decomposition gas F1 supplied as fuel with higher accuracy and in a timely manner, thereby enabling more suitable combustion control to be performed.

[0054] According to the combustion device 60 of this embodiment described above, in addition to the above effect (1), the following effect can be achieved. (2) The control unit 50 includes a combustion condition setting unit 53 that sets combustion conditions including at least one of the combustion amount of the combustion device 60 and the air ratio in combustion. The first memory unit 511 stores the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, further correlating it with the combustion conditions. The ammonia concentration calculation unit 52 acquires the detection result of the NOx concentration sensor 231, which is the NOx concentration detection unit, and the setting result of the combustion condition setting unit 53, and calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result, the setting result, and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1, which is stored in the first memory unit 511 and further associated with the combustion conditions. Therefore, the ammonia concentration calculation unit 52 calculates the ammonia concentration taking into consideration the combustion conditions (at least one of the combustion amount and the air ratio), and therefore the accuracy of calculation of the ammonia concentration in the ammonia decomposition gas F1 can be improved.

[0055] (3) The combustion device 60 is equipped with an oxygen concentration sensor 232, which is an oxygen concentration detection unit that detects the oxygen concentration in the exhaust gas E1. The control unit 50 is equipped with an air ratio calculation unit 54 that calculates the air ratio based on the detection result of the oxygen concentration sensor 232. The combustion condition setting unit 53 acquires the calculation result of the air ratio calculation unit 54 and sets the air ratio as the combustion condition. Therefore, the combustion condition setting unit 53 acquires the calculation result of the air ratio calculation unit 54, which calculates the air ratio from the oxygen concentration in the exhaust gas E1, and sets the air ratio as the combustion condition, so that a more accurate air ratio can be set. For example, if the air ratio in the combustion in the combustion device 60 fluctuates due to some external factor or the like, the air ratio is calculated by the air ratio calculation unit 54 based on the oxygen concentration detected by the oxygen concentration sensor 232, so that the ammonia concentration calculation unit 52 can calculate the ammonia concentration with higher accuracy.

[0056] (Third embodiment) The combustion device 70 of the third embodiment is similar to the combustion device 10 of the first embodiment, except that the memory unit 51 is equipped with a second memory unit 512. Therefore, parts that perform 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 redundant explanations will be omitted as appropriate.

[0057] 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. In the combustion device 70 of the third embodiment, the memory unit 51 of the control unit 50 includes a first memory unit 511 and a second memory unit 512 . The second storage unit 512 stores ammonia management information. The ammonia management information is information that associates a reference value of the ammonia concentration in the ammonia decomposition gas F1 supplied to the combustion device 70 from the fuel supply line 210 with control related to the reference value.

[0058] In this embodiment, the second storage unit 512 stores, as ammonia management information, the first reference value, the second reference value, and the control corresponding thereto, as exemplified below. The first reference value is an ammonia concentration that serves as a reference for reporting an abnormality in the ammonia concentration in the ammonia decomposed gas F1. Furthermore, the control associated with the first reference value is control for reporting an abnormality in the ammonia concentration in the ammonia decomposed gas F1 when the ammonia concentration in the ammonia decomposed gas F1 exceeds the first reference value. The second reference value is an ammonia concentration at which combustion in the combustion device 70 is stopped due to an abnormality in the ammonia concentration in the ammonia decomposition gas F1. The control associated with the second reference value is control that stops combustion in the combustion device 70 when the ammonia concentration in the ammonia decomposition gas F1 exceeds the second reference value.

[0059] In this embodiment, an example will be described in which the first reference value is an ammonia concentration value that is smaller than the second reference value, but the first reference value and the second reference value may be the same value. In addition, it is preferable that the second memory unit 512 stores at least one of the above-mentioned reference values ​​and the control related thereto as ammonia management information, and may store one reference value and the control related thereto, or may store three or more reference values ​​and the control related thereto. The first reference value and the second reference value can be set appropriately depending on the individual combustion device 70 and boiler 1, their usage conditions, and the like.

[0060] The calculation of the ammonia concentration in the combustion device 70 of this embodiment will be described below. In the combustion device 70, the ammonia decomposition gas F1 and 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 produced by the combustion is discharged through an exhaust gas line 230. The NOx concentration sensor 231 detects the NOx concentration in the exhaust gas E1 and outputs the result to the control unit . The ammonia concentration calculation unit 52 calculates the ammonia concentration in the ammonia decomposition gas F1 based on the detection result of the NOx concentration sensor 231 and the relationship between the ammonia concentration in the ammonia decomposition gas F1 and the NOx concentration in the exhaust gas E1 read from the first memory unit 511.

[0061] The control unit 50 acquires the calculation result of the ammonia concentration calculation unit 52, reads out the ammonia management information from the second storage unit 512, and controls the operation of the combustion device 70 based on these. For example, when the ammonia concentration in the ammonia decomposition gas F1 calculated by the ammonia concentration calculation unit 52 exceeds a first reference value, the control unit 50 performs control to notify the user of an abnormality in the ammonia concentration in the ammonia decomposition gas F1. Specifically, the control unit 50 notifies the user of the abnormality in the ammonia concentration by sounding an alarm to notify the user of the abnormality in the ammonia concentration or by displaying a warning on a display unit (not shown).

[0062] This allows the operator of the combustion device 70 and the boiler 1 equipped with the same to know that the ammonia concentration in the ammonia decomposition gas F1 has exceeded the first reference value, and control can be performed to maintain favorable combustion, for example, by adjusting the air ratio in combustion in the burner 11 or by adjusting the amount of ammonia decomposition gas produced in an ammonia decomposition gas production device (not shown), thereby reducing NOx emissions and enabling the combustion device 70 to be operated safely.

[0063] When the ammonia concentration in the ammonia decomposition gas F1 calculated by the ammonia concentration calculation unit 52 exceeds the second reference value, the control unit 50 performs control to stop combustion in the combustion device 70. Specifically, the control unit 50 closes the first shutoff valve 213 and the second shutoff valve 215 of the fuel supply line 210 to stop combustion in the burner 11 and stop operation of the combustion device 70. This prevents the combustion device 70 from burning the ammonia decomposition gas F1 having an abnormal ammonia concentration, thereby suppressing an increase in the NOx concentration in the exhaust gas E1 and leakage of unburned ammonia into the exhaust gas E1, thereby enabling safe operation of the combustion device 70. At this time, the control unit 50 may sound an alarm to notify of the abnormality in the ammonia concentration or display a warning on a display unit (not shown) in addition to controlling the combustion device 70 to stop combustion. The alarm may be the same as or different from the alarm used in the control associated with the first reference value.

[0064] The first and second reference values ​​relate to the ammonia concentration in the ammonia decomposition gas F1, and the ammonia management information is these reference values ​​and control associated with the reference values ​​(notifying of abnormalities in the concentration and stopping the combustion device), so the control unit 50 can perform control according to the ammonia concentration in the ammonia decomposition gas F1, and the combustion device 70 can perform appropriate operation while suppressing emissions of NOx, unburned ammonia, etc.

[0065] In this embodiment, the control unit 50 may include a combustion condition setting unit 53 and an air ratio calculation unit 54, and an oxygen concentration sensor 232 may be provided in the exhaust gas line 230, as in the second embodiment described above. In this case, the concentration calculated by the ammonia concentration calculation unit 52 corresponds to the combustion conditions (air ratio, combustion amount, etc.) of the combustion device, and the ammonia concentration can be calculated with higher accuracy.

[0066] As described above, the combustion device 70 of this embodiment can achieve the following effects in addition to the above effects (1) to (3). (4) The control unit 50 includes a second memory unit 512 that stores ammonia management information that associates a reference value of the ammonia concentration in the ammonia decomposition gas F1 supplied to the combustion device 70 with control related to the reference value, and controls the operation of the combustion device 70 based on the calculation result of the ammonia concentration calculation unit 52 and the ammonia management information stored in the second memory unit 512. Therefore, the combustion device 70 can perform control according to the ammonia concentration in the ammonia decomposition gas F1, and can suppress at least one of the leakage of unburned ammonia and the generation of NOx, thereby achieving suitable operation.

[0067] (5) The ammonia management information includes at least one of: a first reference value, which is an ammonia concentration that serves as a standard for notifying an abnormality in the ammonia concentration in the ammonia decomposition gas F1, associated with control for notifying an abnormality in the ammonia concentration in the ammonia decomposition gas F1; or a second reference value, which is an ammonia concentration that stops combustion in the combustion device 70 due to an abnormality in the ammonia concentration in the ammonia decomposition gas F1, associated with control for stopping combustion in the combustion device 70. Therefore, the control unit 50 issues an alarm about an abnormality in the ammonia concentration and stops the combustion device 70 depending on the ammonia concentration in the ammonia decomposition gas F1, and by performing abnormal response operations and stopping operation, it is possible to prevent abnormal combustion and an increase in harmful substances such as NOx and unburned ammonia in the exhaust gas.

[0068] (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.

[0069] In each embodiment, the combustion device is applied to the boiler 1, but the present invention is not limited to this and may be applied to other devices that burn the ammonia decomposition gas F1 as fuel. For example, the combustion device may be an industrial furnace (heat treatment furnace, sintering furnace, calcination furnace, etc.).

[0070] In each embodiment, an ammonia decomposition gas combustion system may be formed that includes a combustion device, an ammonia decomposition device, and an operation information generating unit (not shown) that generates operation information for the ammonia decomposition device. The operation information includes at least one of the amount of ammonia decomposed in the ammonia decomposition device, the ammonia decomposition reaction temperature, and whether the ammonia decomposition device is stopped. The operation information generation unit is electrically connected to the NOx concentration sensor 231 of the combustion device and the control unit 50, and is capable of acquiring information. The operation information generation unit acquires exhaust gas information from the combustion device 70, including at least one of the detection result of the NOx concentration sensor 231 of the combustion device and the ammonia concentration in the ammonia decomposition gas F1 calculated by the ammonia concentration calculation unit 52 of the control unit 50, and generates operation information for the ammonia decomposition device based on this exhaust gas information. The ammonia decomposition gas combustion system acquires exhaust gas information from the combustion device and controls the operation of the ammonia decomposition device based on the information. Therefore, the amount of ammonia decomposition gas produced by the ammonia decomposition gas device can be suitably controlled in accordance with the combustion state of the combustion device, and NOx, unburned ammonia, etc. emitted from the combustion device can be suppressed.

[0071] The present invention is not limited to the above-described embodiments, but may be combined with other embodiments as desired.

[0072] 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]

[0073] 1 boiler 10,60,70 Combustion equipment 11 Burner 210 Fuel supply line 220 Air supply line 230 Exhaust gas line 231 NOx concentration sensor (NOx concentration detection unit) 232 Oxygen concentration sensor (oxygen concentration detection unit) 50 control section 51 Storage section 511 1st memory section 512 2nd memory section 52 Ammonia concentration calculation unit 53 Combustion condition setting section 54 Air ratio calculation section

Claims

1. a burner that burns the ammonia decomposition gas; a fuel supply line for supplying 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 generated by combustion of the ammonia decomposition gas and combustion air flows; a NOx concentration detection unit that detects the NOx concentration in the exhaust gas; A control unit; Equipped with The control unit a first storage unit that stores a relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas; an ammonia concentration calculation unit that calculates the ammonia concentration in the ammonia decomposition gas based on the detection result of the NOx concentration detection unit and the relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas stored in the first storage unit; A combustion device comprising:

2. the control unit includes a combustion condition setting unit that sets combustion conditions including at least one of a combustion amount of the combustion device and an air ratio in combustion, the first storage unit stores a relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas in further association with the combustion conditions; The ammonia concentration calculation unit The detection result of the NOx concentration detection unit and the setting result of the combustion condition setting unit are acquired, calculating the ammonia concentration in the ammonia decomposition gas based on the detection result, the setting result, and a relationship between the ammonia concentration in the ammonia decomposition gas and the NOx concentration in the exhaust gas, the relationship being stored in the first storage unit and further associated with the combustion conditions; The combustion device of claim 1 .

3. an oxygen concentration detection unit for detecting the oxygen concentration in the exhaust gas; the control unit includes an air ratio calculation unit that calculates an air ratio based on the detection result of the oxygen concentration detection unit, the combustion condition setting unit acquires the calculation result of the air ratio calculation unit and sets the air ratio as the combustion condition. The combustion device according to claim 2.

4. The control unit a second storage unit configured to store ammonia management information that associates a reference value of the ammonia concentration in the ammonia decomposition gas supplied to the combustion device with control related to the reference value; controlling the operation of the combustion device based on the calculation result of the ammonia concentration calculation unit and the ammonia management information stored in the second storage unit. The combustion device of claim 1 .

5. The ammonia management information is A first reference value, which is an ammonia concentration serving as a reference for notifying an abnormality in the ammonia concentration in the ammonia decomposition gas, is associated with control for notifying an abnormality in the ammonia concentration in the ammonia decomposition gas; or a second reference value, which is an ammonia concentration at which combustion in the combustion device is stopped due to an abnormality in the ammonia concentration in the ammonia decomposition gas, being associated with control to stop combustion in the combustion device; Including at least one of The combustion device according to claim 4.

Images