Boiler system

Abstract

The present invention provides a boiler system comprising a boiler that burns fuel containing ammonia and a pollution control device that removes ammonia from the exhaust gas from the boiler, which can prevent ammonia leakage and suppress ammonia emissions to an acceptable level by treating the ammonia even if a malfunction occurs in the boiler system. [Solution] The boiler system includes a boiler, a pollution control device, an exhaust gas line, etc. The boiler includes an economizer, a fluid injection unit that sprays water or injects steam into it, a fluid supply line, a control unit, etc. The control unit includes an exhaust gas information storage unit that acquires exhaust gas information relating to the exhaust gas flowing through the exhaust gas line, an exhaust gas abnormality determination unit that determines an abnormality in the exhaust gas based on the exhaust gas information, and an exhaust gas abnormality control unit that stops the combustion of the boiler and sprays water or injects steam from the fluid injection unit into the economizer based on the determination result of the exhaust gas abnormality determination unit.

Description

Technical Field

[0001] The present invention relates to a boiler system including a boiler that burns a fuel containing ammonia.

Background Art

[0002] Conventionally, in boilers and the like, hydrocarbon fuels such as natural gas and oil fuels have been used. However, in recent years, in order to reduce carbon dioxide emissions, a part of the hydrocarbon fuel is replaced with ammonia that does not generate carbon dioxide during combustion, and various boilers that co-fire a hydrocarbon fuel and ammonia, boilers that burn only ammonia, etc., boilers using a fuel containing ammonia have been developed (see, for example, Patent Documents 1 and 2). When burning a fuel containing ammonia, depending on the combustion state of the boiler and the like, unburned ammonia may be contained in the exhaust gas. Even at a low concentration, leakage of ammonia raises concerns about adverse effects on the surrounding environment and the human body. Therefore, it is encouraged to treat and discharge the ammonia in the exhaust gas so that it is below the allowable concentration, and a decontamination device for removing the ammonia remaining in the exhaust gas of the boiler is used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0005] The present invention aims to provide a boiler system comprising a boiler that burns fuel containing ammonia and a pollution control device that removes ammonia from exhaust gas from the boiler, which can prevent ammonia leakage and suppress ammonia emissions to an acceptable range by treating ammonia even if an abnormality occurs in the boiler system. [Means for solving the problem]

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

[0007] The boiler system of the present invention comprises a boiler that burns a fuel containing ammonia, a decontamination device that removes ammonia contained in the exhaust gas of the boiler, and an exhaust gas line that introduces the exhaust gas generated in the boiler to the decontamination device, wherein the boiler comprises a burner that burns the fuel, an ammonia fuel supply line that supplies the fuel to the boiler, a boiler body that recovers heat from the combustion gas produced by the combustion of the fuel, an economizer that further recovers heat from the combustion gas after heat has been recovered in the boiler body, a fluid injection unit that sprays water or injects steam into the economizer, and the fluid The boiler comprises a fluid supply line that supplies water or steam to an injection unit, and a control unit that controls the operation of the boiler, wherein the control unit comprises an exhaust gas information storage unit, an exhaust gas abnormality determination unit, and an exhaust gas abnormality control unit, the exhaust gas information storage unit acquires and stores exhaust gas information relating to the exhaust gas flowing through the exhaust gas line, the exhaust gas abnormality determination unit determines an abnormality in the exhaust gas based on the exhaust gas information stored in the exhaust gas information storage unit, and the exhaust gas abnormality control unit, based on the determination result of the exhaust gas abnormality determination unit, stops the combustion of the boiler and performs at least one of the following: spraying water or steam from the fluid injection unit to the economizer.

[0008] Furthermore, the boiler system comprises a first opening / closing unit for opening and closing the exhaust gas line, a branch exhaust gas line branching from the upstream side of the first opening / closing unit of the exhaust gas line and through which at least a portion of the exhaust gas flows, a second opening / closing unit provided in the branch exhaust gas line and capable of opening and closing the flow path of the branch exhaust gas line, and a boiler system control unit for controlling the operation of the boiler system. Preferably, when the exhaust gas abnormality determination unit determines that there is an abnormality in the exhaust gas, the boiler system control unit closes the first opening / closing unit and opens the second opening / closing unit, thereby discharging the exhaust gas through the branch exhaust gas line.

[0009] Furthermore, the boiler is provided with a purge gas supply line that supplies purge gas to the ammonia fuel supply line, and the exhaust gas abnormality control unit, when the exhaust gas abnormality determination unit determines that there is an abnormality in the exhaust gas, preferably stops the combustion of the boiler, supplies purge gas from the purge gas supply line to purge the ammonia fuel supply line, and performs at least one of water spraying or steam injection from the fluid injection unit to the economizer.

[0010] Furthermore, the boiler includes a blower for supplying air, an air supply line for supplying the air supplied by the blower to the burner, and an air flow rate adjustment unit for adjusting the air flow rate. Preferably, the exhaust gas abnormality control unit controls the air flow rate adjustment unit when the exhaust gas abnormality determination unit determines an abnormality in the exhaust gas during ammonia combustion of the boiler, and sets the air flow rate to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion of the boiler.

[0011] Furthermore, the boiler system preferably includes an exhaust gas pressure detection unit that detects the pressure of the exhaust gas in the exhaust gas line, the exhaust gas information storage unit acquires and stores the detection result of the exhaust gas pressure detection unit as exhaust gas information, and the exhaust gas abnormality determination unit determines an abnormality in the exhaust gas when the detection result of the exhaust gas pressure detection unit, which is the exhaust gas information, exceeds a predetermined value.

[0012] Furthermore, the boiler system preferably includes an exhaust gas ammonia detection unit for detecting ammonia in the exhaust gas of the exhaust gas line, the exhaust gas information storage unit acquires and stores the detection result of the exhaust gas ammonia detection unit as exhaust gas information, and the exhaust gas abnormality determination unit determines an abnormality in the exhaust gas when the detection result of the exhaust gas ammonia detection unit, which is the exhaust gas information, exceeds a predetermined value. [Effects of the Invention]

[0013] According to the present invention, in a boiler system comprising a boiler that burns fuel containing ammonia and a pollution control device that removes ammonia from exhaust gas from the boiler, it is possible to provide a boiler system that can prevent ammonia leakage and suppress ammonia emissions to an acceptable range by treating the ammonia even if an abnormality occurs in the boiler system. [Brief explanation of the drawing]

[0014] [Figure 1] This is a diagram illustrating a boiler system according to the first embodiment. [Figure 2] This is a diagram illustrating the control unit of the boiler system according to the first embodiment. [Figure 3] This is a time chart diagram illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit and the blower control in the boiler system of the first embodiment when the ammonia concentration in the exhaust gas exceeds a predetermined value. [Figure 4] This is a time chart diagram illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit and the blower control in the boiler system of the first embodiment when the exhaust gas pressure exceeds a predetermined value. [Figure 5] This is a diagram illustrating a boiler system according to a second embodiment. [Figure 6] This is a time chart diagram illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit and the blower control in the boiler system of the second embodiment when the ammonia concentration in the exhaust gas exceeds a predetermined value. [Figure 7] This is a time chart diagram illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit and the blower control in the boiler system of the second embodiment when the exhaust gas pressure exceeds a predetermined value. [Figure 8] This is a diagram illustrating a boiler system according to a third embodiment. [Figure 9] This is a time chart diagram illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit and the blower control in the boiler system of the third embodiment when the ammonia concentration in the exhaust gas exceeds a predetermined value. [Figure 10]This is a time chart for explaining the exhaust gas cleaning control of the exhaust gas abnormality control unit and the control of the blower when the exhaust gas pressure exceeds a predetermined value in the boiler system of the third embodiment.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. Note that each of the drawings shown below, including FIG. 1, is a schematic diagram, and the sizes and shapes of each part are appropriately exaggerated for easy understanding.

[0016] (First Embodiment) FIG. 1 is a diagram for explaining the boiler system 1 of the first embodiment. FIG. 2 is a diagram for explaining the control unit 70 of the boiler system 1 of the first embodiment. The boiler system 1 of the present embodiment includes a boiler 10, a decontamination device 80, and the like. The boiler 10 of the present embodiment is a boiler that burns fuel containing ammonia, and includes a can body 11, a burner 12, an economizer 55, an exhaust gas pressure sensor 41, an exhaust gas ammonia sensor 46, a water sprinkling part 57 as a fluid injection part, a first fuel supply line L100, an ammonia fuel supply line L200, an air supply line L300, a water supply line L500, a second water supply line L520 as a fluid supply line, a purge gas supply line L600, a steam supply line (not shown), and a control unit 70 that controls the operation of the boiler 10. Further, the boiler system 1 includes this boiler 10, a decontamination device 80, and an exhaust gas line L400 that sends the exhaust gas E1 discharged from the boiler 10 to the decontamination device 80. Note that the "line" in this specification is a general term for a flow path, a route, a pipeline, and the like.

[0017] The boiler 10 of this embodiment is an ammonia co-firing boiler that simultaneously burns ammonia fuel F2 and a first fuel F1, which burns faster than ammonia, in the burner 12. In addition to simultaneous combustion of ammonia fuel F2 and the first fuel F1, the boiler 10 of this embodiment may also be a boiler capable of burning only ammonia fuel F2 (ammonia-only combustion). Furthermore, the boiler 10 in this embodiment is a steam boiler that burns ammonia fuel F2 and first fuel F1 to heat water and generate steam, and supplies steam to load equipment (not shown) via a steam supply line (not shown).

[0018] Furthermore, ammonia fuel F2 includes not only ammonia alone, but also a mixed gas containing ammonia in which ammonia (NH3) accounts for 20% or more of the volume concentration of the components constituting the gaseous fuel, and ammonia decomposition gas produced by the decomposition of ammonia. In this embodiment, the ammonia fuel F2 will be described using the example of ammonia. Furthermore, in this specification, "ammonia contained in exhaust gas" refers to unburned ammonia contained in exhaust gas E1 when ammonia fuel F2 does not burn completely, and ammonia remaining in the piping of the ammonia fuel supply line L200 etc. which is mixed into exhaust gas E1 after the boiler has stopped burning.

[0019] The boiler body 11 is composed of a lower header, multiple water pipes, an upper header, a combustion space (none of which are shown), etc. The boiler body 11 recovers heat from the combustion gas generated when fuel is burned in the combustion space, and heats the water (feedwater W1) supplied to the boiler body 11 from the first feedwater line L510 (described later) to generate steam.

[0020] The burner 12 is located at the top of the boiler body 11. The burner 12 is connected to the first fuel supply line L100 and the ammonia fuel supply line L200. In addition, the wind box 13 is connected to the air supply line L300, which supplies combustion air A1 to the burner 12. The burner 12 injects the first fuel F1 and ammonia fuel F2, burning the first fuel F1 and ammonia fuel F2 in the combustion space of the boiler 11. In this embodiment, first, the first fuel F1 and combustion air A1 are supplied to the burner 12, and combustion begins. Next, ammonia fuel F2 is supplied to the combustion section of the first fuel F1, and a predetermined amount of combustion air A1 corresponding to the total amount of the first fuel F1 and ammonia fuel F2 is supplied to the burner 12. As a result, the boiler 10 begins co-firing the ammonia fuel F2 and the first fuel F1.

[0021] The first fuel supply line L100 supplies the first fuel F1 from a fuel source (not shown) to the burner 12. The first fuel supply line L100 is equipped with shut-off valves V11 and V13 and a flow control valve V12. The shut-off valves V11 and V13 are composed of solenoid valves and open and close the flow path of the first fuel supply line L100 to supply or stop the first fuel F1. The shut-off valves V11 and V13 are connected to the control unit 70 via wired or wireless communication and are controlled by signals transmitted from the control unit 70. In this embodiment, in the first fuel supply line L100, the shut-off valve V11 is located upstream of the shut-off valve V13.

[0022] The flow control valve V12 is a control valve that adjusts the flow rate of the first fuel F1 by adjusting the opening degree of the valve. The flow control valve V12 is connected to the control unit 70 via wired or wireless communication, and the control unit 70 transmits a signal to the flow control valve V12 to control the opening degree according to the required combustion amount. In this embodiment, the flow control valve V12 is located in the first fuel supply line L100 between shut-off valve V11 and shut-off valve V13.

[0023] The first fuel F1 is a fuel with a faster combustion rate than ammonia. The first fuel F1 may be a liquid fuel or a gaseous fuel. As a liquid fuel, oil fuels, alcohol fuels, etc., can be used as the first fuel. As a gaseous fuel, hydrogen-based fuel gases including hydrogen gas or hydrogen-containing mixed gases, liquefied natural gas (hereinafter referred to as LNG), liquefied petroleum gas (LPG), city gas (13A), and other hydrocarbon gases can be used. In this embodiment, as an example, an example in which city gas 13A is used as the first fuel F1 will be described.

[0024] The ammonia fuel supply line L200 supplies ammonia fuel F2 from a fuel source (not shown) to the burner 12. The ammonia fuel supply line L200 is equipped with shut-off valves V21 and V23 and a flow control valve V22. The shut-off valves V21 and V23 are composed of solenoid valves and open and close the flow path of the ammonia fuel supply line L200 to supply or stop the ammonia fuel F2. The shut-off valves V21 and V23 are connected to the control unit 70 via wired or wireless communication and are controlled by signals transmitted from the control unit 70. In this embodiment, in the ammonia fuel supply line L200, the shut-off valve V21 is located upstream of the shut-off valve V23.

[0025] The flow control valve V22 is a control valve that adjusts the flow rate of ammonia fuel F2 by adjusting the opening degree of the valve. The flow control valve V22 is connected to the control unit 70 via wired or wireless communication, and the control unit 70 transmits a signal to the flow control valve V22 to control the opening degree according to the required combustion amount. In this embodiment, the flow control valve V22 is located in the ammonia fuel supply line L200 between shut-off valve V21 and shut-off valve V23.

[0026] The purge gas supply line L600 supplies purge gas G1 from a purge gas supply source (not shown) to the ammonia fuel supply line L200. The upstream side of the purge gas supply line L600 is connected to the purge gas supply source, and the downstream side of the purge gas supply line L600 is connected to the downstream side of the shut-off valve V23 of the ammonia fuel supply line L200 and in the vicinity of the shut-off valve V23. The purge gas supply line L600 is equipped with shut-off valves V61, V62, etc.

[0027] The shut-off valves V61 and V62 are composed of solenoid valves and open and close the flow path of the purge gas supply line L600 to supply or stop the purge gas G1. The shut-off valves V61 and V62 are connected to the control unit 70 via wired or wireless communication and are controlled by signals transmitted from the control unit 70. The purge gas supply line L600 is further equipped with a flow sensor and an orifice (not shown). The flow sensor is a detection unit that detects the flow rate of the purge gas G1. The flow sensor is connected to the control unit 70 via wired or wireless communication, and the control unit 70 can acquire the detection result of the flow sensor. As the purge gas G1, gases such as nitrogen, helium, and neon, hydrocarbon gases such as methane, and city gas can be used. In this embodiment, an example in which nitrogen is used as the purge gas G1 will be explained.

[0028] The air supply line L300 supplies combustion air A1 to the burner 12. The upstream end of the air supply line L300 is connected to the blower 31, and the downstream end of the air supply line L300 is connected to the wind box 13. The air supply line L300 comprises the blower 31 and the damper 33, from upstream to downstream. The blower 31 supplies combustion air A1 to the burner 12. The blower 31 comprises a fan and a motor that rotates the fan, and the rotation speed of the motor can be adjusted by controlling the frequency with an inverter 32. Therefore, the amount of combustion air A1 supplied to the burner 12 can be adjusted by controlling the frequency of the inverter 32. The inverter 32 is connected to the control unit 70 via wired or wireless communication and is controlled by signals transmitted from the control unit 70.

[0029] The damper 33 adjusts the amount of combustion air A1 supplied to the burner 12 by adjusting the damper's opening. Specifically, the damper 33 is rotatably positioned between a closed state, which blocks the flow path of the air supply line L300, and an open state, which rotates from this closed state to a predetermined angle (e.g., 90 degrees) to open the flow path of the air supply line L300. The damper 33 is communicated with the control unit 70 by wire or wireless means and is controlled by signals transmitted from the control unit 70. The inverter 32 and damper 33 are an air flow rate adjustment unit that adjusts the flow rate of combustion air A1 supplied to the burner 12. However, the air flow rate adjustment unit is not limited to this configuration; it may consist of either the inverter 32 or the damper 33.

[0030] The combustion gas generated by the combustion of at least one of the first fuel F1 and ammonia fuel F2 is heat-exchanged in the boiler 11, then heat-exchanged again in the economizer 55, and flows through the exhaust gas line L400 as exhaust gas E1. The upstream side of the exhaust gas line L400 is connected to the economizer 55, and the downstream side of the exhaust gas line L400 is connected to the damper 42 of the pollution control device 80. The economizer 55 is a heat exchanger that exchanges heat between the combustion gas, which has undergone heat exchange in the boiler 11, and the feedwater W1. The feedwater W1 heated in the economizer 55 is supplied to the lower header (not shown) of the boiler 11, where it is heated by the combustion gas and turned into steam.

[0031] An exhaust gas pressure sensor 41, which is an exhaust gas pressure detection unit that detects the pressure of the exhaust gas E1 in the exhaust gas line L400 (hereinafter referred to as exhaust gas pressure), is provided at the exhaust gas outlet of the economizer 55. The exhaust gas pressure sensor 41 is connected to the control unit 70 via wired or wireless communication, and the detection result of the exhaust gas pressure sensor 41 can be acquired by the control unit 70. The exhaust gas pressure sensor 41 may be installed in a location other than the one shown in Figure 1, as long as the exhaust gas pressure can be detected, for example, it may be installed in the exhaust gas line L400.

[0032] Furthermore, an exhaust gas ammonia sensor 46 is provided at the exhaust gas outlet of the economizer 55 as an exhaust gas ammonia detection unit, which detects the ammonia concentration in the exhaust gas E1 of the exhaust gas line L400. The exhaust gas ammonia sensor 46 is connected to the control unit 70 via wired or wireless communication, and the detection results of the exhaust gas ammonia sensor 46 can be obtained by the control unit 70. Note that the exhaust gas ammonia sensor 46 may be installed at a location other than the one shown in Figure 1, as long as it can detect the ammonia concentration in the exhaust gas E1, for example, it may be installed in the exhaust gas line L400.

[0033] The water supply line L500 supplies water W1 from a water source (not shown) to the boiler 10 and also supplies water W2 to the water spraying section 57, which is a fluid injection section. The water supply line L500 is equipped with a pump 51, the upstream side of which is connected to a water source (not shown), and the downstream side of the pump 51 branches into a first water supply line L510 and a second water supply line L520. Pump 51 adjusts the amount of water flowing through the water supply line L500. Note that, in addition to pump 51, a flow control valve or other device capable of adjusting the water supply amount may also be provided.

[0034] The first water supply line L510 is connected to the water supply line L500 on its upstream side and to the lower header of the boiler 11 via the economizer 55 on its downstream side. The first water supply line L510 is equipped with shut-off valves V52 and V53 and a flow control valve V54.

[0035] The shut-off valves V52 and V53 are composed of solenoid valves and open and close the flow path of the first water supply line L510 to supply or stop the water supply W1. The shut-off valves V52 and V53 are connected to the control unit 70 via wired or wireless communication and are controlled by signals transmitted from the control unit 70. The flow control valve V54 is a control valve that adjusts the flow rate of the water supply W1 by adjusting the degree of valve opening. The flow control valve V54 is connected to the control unit 70 via wired or wireless communication, and the control unit 70 transmits a signal to the flow control valve V54 to control the degree of opening according to the required combustion amount. In this embodiment, the boiler 10 and boiler system 1 will be described using an example where the feedwater to the boiler 10 is a continuous feedwater supply that continuously supplies an amount of water that has been converted into steam according to the amount of combustion.

[0036] The second water supply line L520 is a fluid supply line that supplies water W2 to the watering unit 57. The upstream side of the second water supply line L520 is connected to the downstream side of the pump 51, and the downstream side is connected to the watering unit 57. The second water supply line L520 is also equipped with a shut-off valve V56. The shut-off valve V56 opens and closes the flow path of the second water supply line L520 to supply or stop water W2 to the watering unit 57. The shut-off valve V56 is connected to the control unit 70 via wired or wireless communication and is controlled by signals transmitted from the control unit 70.

[0037] The water spraying unit 57 is a fluid injection unit that sprays water onto the economizer 55. The water spraying unit 57 is positioned above the economizer 55 and sprays water W2 toward the heat exchanger of the economizer 55. As a result, at least a portion of the ammonia in the ammonia-containing gas passing through the economizer 55 dissolves in the sprayed water W2, and the ammonia is removed.

[0038] A blowdown discharge line L420 is provided near the bottom of the economizer 55. Water W2 containing dissolved ammonia, sprayed from the water spraying section 57, is discharged as blowdown from the blowdown discharge line L420 to the outside of the system (outside the boiler system 1). Since a blowdown discharge line L420 is generally located near the economizer 55, the water W2 containing dissolved ammonia can be easily discharged from the blowdown discharge line L420. Furthermore, by spraying the water W2 onto the heat exchanger of the economizer 55, the ammonia can be efficiently dissolved in the water W2 and removed by utilizing the water film on the heat exchanger.

[0039] In addition to the above example, the water spraying unit 57 may also be provided in the exhaust gas line L400 independently of the boiler 10. Furthermore, although the example shown illustrates that the water W2 supplied to the watering unit 57 is supplied by a second feedwater line L520 branched from the feedwater line L500 that supplies water to the boiler 10, the system is not limited to this, and water may be supplied from a feedwater system separate from the feedwater line L500.

[0040] The control unit 70 controls various operations, such as the operation of the boiler 10. As shown in Figure 2, the control unit 70 includes a storage unit 71, an exhaust gas abnormality determination unit 73, and an exhaust gas abnormality control unit 74. The control unit 70 is composed of 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 70 are realized, for example, by executing predetermined software (programs) stored in the memory unit 71. The various functions of the control unit 70 may be realized through the cooperation of hardware and software, or they may be realized by hardware (electronic circuits) alone.

[0041] During combustion of the boiler 10, the control unit 70 opens the shut-off valves V11 and V13 of the first fuel supply line L100 and the shut-off valves V21 and V23 of the ammonia fuel supply line L200, supplying the first fuel F1 and ammonia fuel F2 to the burner 12. The control unit 70 also opens the damper 33, supplying combustion air A1 from the blower 31 to the burner 12. The combustion gas produced by combustion is heat-exchanged with the feedwater W1 in the boiler 11, then heat-exchanged with the feedwater W1 in the economizer 55, and finally discharged as exhaust gas E1 to the exhaust gas line L400. The exhaust gas E1 is then drawn to the abatement device 80 by the induced draft fan 44 (described later), where the ammonia in the exhaust gas E1 is removed to a predetermined concentration or lower, and then discharged from the second exhaust gas line L430.

[0042] The memory unit 71 stores various setting information. In addition, the memory unit 71 stores reference values ​​(exhaust gas information reference values) such as the ammonia concentration and exhaust gas pressure in the exhaust gas E1, which the exhaust gas abnormality determination unit 73 uses to determine exhaust gas abnormalities, with respect to the exhaust gas information described later. Furthermore, the storage unit 71 includes an exhaust gas information storage unit 72. The exhaust gas information storage unit 72 acquires and stores exhaust gas information regarding the exhaust gas E1 flowing through the exhaust gas line L400. The exhaust gas information storage unit 72 stores at least one of the detection results of the exhaust gas pressure sensor 41 (exhaust gas pressure) and the detection results of the exhaust gas ammonia sensor 46 (ammonia concentration in exhaust gas E1) as exhaust gas information.

[0043] The exhaust gas abnormality determination unit 73 determines an abnormality in exhaust gas E1 based on the exhaust gas information stored in the exhaust gas information storage unit 72. Specifically, the exhaust gas abnormality determination unit 73 determines an abnormality in exhaust gas E1 based on the exhaust gas information stored in the exhaust gas information storage unit 72 and standard values ​​(exhaust gas information standard values) such as ammonia concentration and exhaust gas pressure in the exhaust gas stored in the storage unit 71. For example, the exhaust gas abnormality determination unit 73 determines that exhaust gas E1 is abnormal if the exhaust gas pressure in the exhaust gas information stored in the exhaust gas information storage unit 72 deviates from a predetermined value (standard value for exhaust gas pressure). In addition, the exhaust gas abnormality determination unit 73 determines that exhaust gas E1 is abnormal if the ammonia concentration in exhaust gas E1 in the exhaust gas information stored in the exhaust gas information storage unit 72 exceeds a predetermined value (standard value for ammonia concentration in exhaust gas). In this embodiment, the exhaust gas abnormality determination unit 73 determines an abnormality in exhaust gas E1 when, at least one of the following occurs: the exhaust gas pressure in the exhaust gas information stored in the exhaust gas information storage unit 72 is greater than a predetermined value (a reference value for exhaust gas pressure stored in the storage unit 71), or the ammonia concentration in exhaust gas E1 in the exhaust gas information stored in the exhaust gas information storage unit 72 is greater than a predetermined value (a reference value for ammonia concentration in exhaust gas stored in the storage unit 71).

[0044] Furthermore, if the reference values ​​(exhaust gas information reference values) such as the ammonia concentration and exhaust gas pressure in the exhaust gas stored in the memory unit 71 have a predetermined numerical range, the exhaust gas abnormality determination unit 73 will determine an abnormality in the exhaust gas E1 if the exhaust gas pressure in the exhaust gas information stored in the exhaust gas information memory unit 72 deviates from the predetermined pressure range, or if the ammonia concentration in the exhaust gas E1 in the exhaust gas information stored in the exhaust gas information memory unit 72 exceeds the predetermined concentration range.

[0045] In this embodiment, when the exhaust gas abnormality determination unit 73 determines that there is an abnormality in the exhaust gas E1, the exhaust gas abnormality control unit 74 performs the following exhaust gas abnormality control: combustion stop control of the boiler 10 and exhaust gas cleaning control by spraying water from the water spraying unit 57, which is a fluid injection unit, to the economizer 55. Details of these will be described later. Furthermore, in this embodiment, when the exhaust gas abnormality determination unit 73 determines that there is an abnormality in the ammonia concentration in the exhaust gas E1 (an abnormality in exhaust gas E1 caused by an abnormality on the boiler 10 side, as described later), the exhaust gas abnormality control unit 74 controls the damper 33 and inverter 32, which are air flow rate adjustment units, to set the flow rate of air A1 supplied to the burner 12 to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion of the boiler 10.

[0046] The boiler system 1 comprises a boiler 10, an exhaust gas line L400, and a pollution control device 80. The exhaust gas line L400 is connected upstream to the economizer 55 of the boiler 10 and downstream to the damper 42 of the pollution control device 80. The exhaust gas line L400 introduces the exhaust gas E1 discharged from the boiler 10 into the pollution control device 80.

[0047] The abatement device 80 is a device that abates ammonia in the exhaust gas E1, and removes ammonia by dissolving it through methods such as water spraying. The abatement device 80 comprises a damper 42, an induced draft fan 44, and an abatement device control unit (not shown). In this embodiment, the exhaust gas E1 from which ammonia has been removed by the abatement device 80 is discharged out of the system from a second exhaust gas line L430 located downstream of the abatement device 80.

[0048] The damper 42 is connected to the exhaust gas line L400 and adjusts the flow rate of exhaust gas E1 discharged to the abatement device 80. The damper 42 is rotatably positioned to be closed, blocking the flow path of the exhaust gas line L400, and open, rotating from this closed state to a predetermined angle (e.g., 90 degrees) to open the flow path of the exhaust gas line L400. The damper 42 is communicated via wired or wireless means with an abatement device control unit (not shown), which will be described later, and is controlled by signals transmitted from the abatement device control unit.

[0049] The induced draft fan 44 is installed in the exhaust gas line L400 and is a fan capable of drawing exhaust gas E1 into the abatement device 80. The induced draft fan 44 is connected to the abatement device control unit via wired or wireless communication, and the rotation speed of the induced draft fan 44 (amount of exhaust gas E1 drawn in) is controlled by a signal transmitted from the abatement device control unit. The rotation speed of the induced draft fan 44 is controlled by the abatement device control unit so that the pressure of an exhaust gas pressure sensor (not shown) installed at the inlet (near the upstream side) of the induced draft fan 44 becomes a predetermined pressure. In addition, the rotation speed of the induced draft fan 44 is controlled by the abatement device control unit to achieve an induced draft flow rate corresponding to the combustion rate of the boiler 10.

[0050] The pollution control unit controls the operation of the pollution control unit 80. In this embodiment, the pollution control unit is connected to the control unit 70 of the boiler 10 via wired or wireless communication, and the pollution control unit 80 can acquire operating information of the boiler 10, and the boiler 10 can acquire operating information of the pollution control unit 80. For example, if the pollution control unit 80 stops operating, a stop signal is sent to the control unit 70.

[0051] In the boiler system 1, if the boiler 10 is shut down due to an abnormality on the boiler 10 side or an abnormality on the pollution control device 80 side, the control unit 70 performs exhaust gas abnormality control. Examples of abnormalities on the boiler 10 side include, for example, a condition in which the air-fuel ratio of the boiler 10 deviates from a predetermined range due to a malfunction in at least one of the fuel supply system or the combustion air supply system of the boiler 10; a condition in which the boiler furnace pressure deviates from a predetermined range and fluctuates, causing oscillating combustion in which the furnace pressure and flame intensify each other's fluctuations; or a condition in which the mixing of ammonia fuel F2 and combustion air A1 deteriorates due to an abnormality such as the uneven flow of at least one of the ammonia fuel F2 and combustion air A1 ejected from the burner 12. If combustion continues under these conditions, the ammonia concentration in the exhaust gas E1 may increase, potentially exceeding the ammonia removal capacity of the ammonia removal device 80.

[0052] Examples of abnormalities on the abatement device 80 side include, for example, the abatement device 80 stopping operation due to a malfunction or blockage of the abatement device 80. In such cases, the abatement device 80 will not be able to properly remove ammonia contained in the exhaust gas E1, increasing the risk of ammonia leakage outside the system. Furthermore, such abnormalities on the abatement device 80 side are abnormalities that cause an increase in exhaust gas pressure.

[0053] If an abnormality occurs on the boiler 10 side or the abatement device 80 side as described above, the boiler system 1 is required to quickly stop the combustion of ammonia fuel F2 and to suppress the increase in ammonia emissions outside the system (outside the boiler system 1) caused by unburned ammonia in the exhaust gas E1 being discharged without being removed by the abatement device 80, or by residual ammonia in the piping of the ammonia fuel supply line L200 of the boiler 10 being discharged by in-furnace purging, etc.

[0054] An example of exhaust gas abnormality control in the event of an abnormality on the boiler 10 side is described below. During combustion of the boiler 10, the exhaust gas ammonia sensor 46 detects the ammonia concentration in the exhaust gas E1 at predetermined timings. The detection result of the exhaust gas ammonia sensor 46 is acquired and stored as exhaust gas information by the exhaust gas information storage unit 72. If an abnormality occurs on the boiler 10 side, the ammonia concentration in the exhaust gas E1 increases. The exhaust gas abnormality determination unit 73 determines that the abnormality in exhaust gas E1 is caused by an abnormality on the boiler 10 side if the ammonia concentration in the exhaust gas E1, which is exhaust gas information stored in the exhaust gas information storage unit 72, exceeds a predetermined value, that is, a standard value for the ammonia concentration in the exhaust gas stored in the storage unit 71 (exhaust gas information standard value). The exhaust gas abnormality control unit 74, upon receiving a determination of an abnormality in the exhaust gas E1 from the exhaust gas abnormality determination unit 73, performs exhaust gas cleaning control and combustion stop control, which are exhaust gas abnormality control functions.

[0055] The exhaust gas abnormality control unit 74 starts the operation of the pump 51, opens the shut-off valve V56, and starts spraying water from the water spraying unit 57 to the heat exchanger of the economizer 55 as exhaust gas cleaning control. Unburned ammonia contained in the exhaust gas E1 dissolves in the sprayed water particles and the water film on the surface of the heat exchanger as it passes through the economizer 55. The water W2 containing dissolved ammonia is discharged from the system as blowdown through the blowdown discharge line L420 and treated by a treatment device (not shown). Furthermore, the exhaust gas abnormality control unit 74 controls the combustion stop of the boiler 10 by closing shut-off valves V11 and V13 and shut-off valves V21 and V23, thereby stopping the supply of the first fuel F1 and ammonia fuel F2. As a result, the combustion of the boiler 10 stops.

[0056] Figure 3 is a time chart illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 in the boiler system 1 of the first embodiment when the ammonia concentration in the exhaust gas E1 exceeds a predetermined value. In Figure 3 and Figure 4 described later, time t1 is the time when the exhaust gas abnormality control unit 74 starts exhaust gas cleaning, and time t2 is the time when the exhaust gas abnormality control unit 74 finishes exhaust gas cleaning. The exhaust gas abnormality control unit 74 starts operating the pump 51 as exhaust gas cleaning control, opens the shut-off valve V56 of the second water supply line L520, and starts supplying water W2 from the second water supply line L520 to the water spraying unit 57. As a result, water spraying by the economizer 55 from the water spraying unit 57 begins (time t1). Furthermore, the exhaust gas abnormality control unit 74 performs combustion stop control of the boiler 10 simultaneously with the exhaust gas cleaning control (at time t1).

[0057] Furthermore, as part of the combustion stop control, the exhaust gas abnormality control unit 74 continues to operate the blower 31 and supplies air A1 to the boiler 10. At this time, the exhaust gas abnormality control unit 74 controls the damper 33 and inverter 32, which are air flow rate adjustment units, to set the flow rate of air A1 flowing through the air supply line L300 to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion of the boiler 10. As a result, the ammonia-containing gas in the burner 12 and boiler 11 is sent to the economizer 55 at a slower speed than during combustion, along with the air A1, and the residence time in the economizer 55 is extended. Therefore, the removal of ammonia by water spraying can be performed more effectively. Consequently, the boiler system 1 can more effectively remove ammonia remaining in the boiler 10 when the boiler 10 is shut down.

[0058] Furthermore, the exhaust gas abnormality control unit 74 transmits to the abatement device control unit the start of exhaust gas cleaning control due to an abnormality on the boiler 10 side. Upon receiving this, the abatement device control unit continues to open the damper 42 and operate the induced draft fan 44 as part of the exhaust gas cleaning control, and the abatement device 80 removes ammonia from the exhaust gas E1. However, the exhaust gas abnormality control unit 74 may also transmit a signal to the abatement device control unit via the control unit 70 instructing the damper 42 to open and the induced draft fan 44 to continue operating, or the control unit 70 may transmit a signal to the abatement device control unit instructing the damper 42 to open and the induced draft fan 44 to continue operating.

[0059] After passing through the economizer 55, the exhaust gas E1 has at least some of its ammonia removed by water spraying, and then flows through the damper 42 and induced draft fan 44 to the abatement device 80. In the abatement device 80, the ammonia in the exhaust gas E1 is removed to a concentration within an acceptable range, and then discharged out of the system. The exhaust gas abnormality control unit 74, after spraying water from the water spraying unit 57 for a predetermined time, stops the operation of the pump 51 and closes the shut-off valve V56, thereby ending the exhaust gas cleaning (time t2). The exhaust gas abnormality control unit 74 also stops the operation of the blower 31, thereby stopping the operation of the boiler 10. The control unit 70 transmits the boiler 10's shutdown to the abatement device control unit of the abatement device 80. Upon receiving this, the abatement device control unit closes the damper 42, stops the operation of the induced draft fan 44, and stops the operation of the abatement device 80. The abatement device control unit may also stop the abatement device 80 after a predetermined time has elapsed since receiving the message. As a result, the boiler system 1 stops operation.

[0060] Next, an example of exhaust gas abnormality control in the event of an abnormality on the abatement device 80 side will be described below. An abnormality on the abatement device 80 side may include, for example, operation stopping due to a malfunction of the abatement device 80, resulting in blockage of the exhaust gas line L400, or blockage of the abatement device 80. During combustion of the boiler 10, the exhaust gas pressure sensor 41 detects the exhaust gas pressure in the exhaust gas line L400. The detection result of the exhaust gas pressure sensor 41 is stored as exhaust gas information in the exhaust gas information storage unit 72.

[0061] When the abatement device 80 becomes blocked, the exhaust gas pressure in the exhaust gas line L400 increases. The exhaust gas abnormality determination unit 73 determines that the exhaust gas abnormality in exhaust gas E1 is caused by an abnormality in the abatement device 80 when the exhaust gas pressure, which is exhaust gas information stored in the exhaust gas information storage unit 72, exceeds a predetermined value, i.e., the standard value of exhaust gas pressure stored in the storage unit 71 (exhaust gas information standard value). The exhaust gas abnormality control unit 74, upon receiving a determination of an abnormality in exhaust gas E1 from the exhaust gas abnormality determination unit 73, performs exhaust gas cleaning control and combustion stop control as exhaust gas abnormality control. The exhaust gas cleaning control and combustion stop control performed by the exhaust gas abnormality control unit 74 when the exhaust gas E1 abnormality is caused by an abnormality on the abatement device 80 side differ from the exhaust gas cleaning control and combustion stop control performed when the exhaust gas E1 abnormality is caused by an abnormality on the boiler 10 side, as described above, in that it controls the damper 42 and induced draft fan 44 and the blower 31.

[0062] FIG. 4 is a time chart for explaining the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 when the exhaust gas pressure exceeds a predetermined value in the boiler system 1 of the first embodiment. First, as exhaust gas cleaning control, the exhaust gas abnormality control unit 74 starts the operation of the pump 51, opens the shut-off valve V56 of the second water supply line L520, and starts supplying water W2 from the second water supply line L520 to the water spray section 57. As a result, water spraying from the economizer 55 by the water spray section 57 is started (time point t1).

[0063] Simultaneously with the start of exhaust gas cleaning (water spraying), the exhaust gas abnormality control unit 74 performs combustion control to stop the combustion of the boiler 10. Further, as part of the combustion stop control, the exhaust gas abnormality control unit 74 stops the operation of the blower 31 simultaneously with the stop of the combustion of the boiler 10, and stops the supply of air A1 to the boiler 10. Note that the exhaust gas abnormality control unit 74 is not limited to this, and may stop the operation of the blower 31 and stop the supply of air A1 to the boiler 10 after a predetermined time α has elapsed from the stop of the combustion of the boiler 10 (however, t1 < t1 + α < t2). This predetermined time α is, for example, the time until the combustion gas in the furnace passes through the economizer 55. By adopting such a form, ammonia can be removed from the combustion gas remaining in the furnace. Further, the exhaust gas abnormality control unit 74 transmits to the decontamination device control unit the start of exhaust gas cleaning control due to an abnormality on the decontamination device 80 side. When receiving this, the decontamination device control unit closes the damper 42 and stops the operation of the induced draft fan 44 as part of the exhaust gas cleaning control, and stops the introduction of the exhaust gas E1 into the decontamination device 80.

[0064] By performing the above-described control, the exhaust gas E1 that has passed through the economizer 55 during water spraying stays in the exhaust gas line L400 in a state where at least part of the ammonia has been removed by the water spraying. Therefore, for example, even when the exhaust gas E1 staying in the flue diffuses into the atmosphere from the second exhaust gas line L430, leakage of ammonia to the outside of the system can be suppressed.

[0065] The exhaust gas abnormality control unit 74 sprays water from the water spraying unit 57 for a predetermined time, then stops the operation of the pump 51 and closes the shut-off valve V56, ending the exhaust gas cleaning (time t2). As a result, the boiler 10 stops operating. The control unit 70 transmits the boiler 10 shutdown to the pollution control unit (not shown). Upon receiving this, the pollution control unit stops the operation of the pollution control unit 80. As a result, the boiler system 1 stops operating.

[0066] As described above, according to this embodiment, in the case of an abnormal shutdown due to a malfunction on the boiler 10 side, or an abnormal shutdown due to a malfunction on the abatement device 80 side, the boiler system 1 can shut down while suppressing the discharge of ammonia to the outside of the system.

[0067] In this embodiment, in the combustion stop control of the boiler 10, pipe purging control may be performed by supplying purge gas G1 from the purge gas supply line L600 to purge the ammonia fuel supply line L200. In the piping purge control system, shut-off valves V61 and V62 on the purge gas supply line L600 are opened to supply purge gas G1 to the ammonia fuel supply line L200, thereby purging the ammonia fuel supply line L200 (pipe purging). After purging for a predetermined time, shut-off valves V61 and V62 on the purge gas supply line L600 are closed to complete the purging process. This allows the ammonia fuel F2 remaining in the piping of the ammonia fuel supply line L200 to be discharged into the furnace and sent to the economizer 55 together with the combustion air A1 or exhaust gas. Therefore, the boiler system 1 can more effectively remove ammonia contained in the gas remaining in the piping.

[0068] As described above, this embodiment can achieve the following effects. (1) According to the boiler system 1 of this embodiment, if an abnormality in exhaust gas E1 occurs due to a malfunction in the boiler 10 or the abatement device 80, the exhaust gas abnormality control unit 74 sprays water from the water spraying unit 57, which is a fluid injection unit, to the economizer and stops the combustion of the boiler 10, thereby dissolving the ammonia remaining in the boiler 10 in water W2 and removing ammonia from the gas present in the boiler 10. Therefore, in a boiler system 1 equipped with a boiler 10 that burns fuel containing ammonia, even if an abnormality occurs in the boiler system 1, the leakage of ammonia can be prevented by processing the ammonia, and the emission of ammonia can be suppressed to an acceptable range. Furthermore, according to the boiler system 1 of this embodiment, the removal of ammonia from the ammonia-containing gas remaining in the boiler 10 is performed by spraying water onto the economizer 55. Therefore, there is no need to install a washing tower or the like with built-in packing material in the exhaust gas line L400, which can suppress increases in the cost and installation space of the boiler system 1.

[0069] (2) According to the boiler system 1 of this embodiment, when the exhaust gas abnormality determination unit 73 determines that there is an abnormality in the exhaust gas E1 during ammonia combustion in the boiler 10, the exhaust gas abnormality control unit 74 controls the inverter 32 and damper 33, which are air flow rate adjustment units, to set the flow rate of air A1 to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion in the boiler 10. As a result, the residence time of the combustion gas containing ammonia in the economizer 55 is extended, and the boiler system 1 can remove ammonia more effectively from the ammonia-containing gas in the boiler 10.

[0070] (3) According to the boiler system 1 of this embodiment, the exhaust gas abnormality determination unit 73 determines an abnormality in exhaust gas E1 when the ammonia concentration in the exhaust gas E1, which is acquired and stored by the exhaust gas information storage unit 72, exceeds a predetermined value. As a result, the control unit 70 can detect an abnormality on the boiler 10 side, such as unstable combustion on the boiler 10 side (abnormal air ratio, oscillating combustion, etc.). Furthermore, the exhaust gas abnormality control unit 74 can control each part in a manner corresponding to when the exhaust gas abnormality is caused by a problem on the boiler 10 side.

[0071] (4) According to the boiler system 1 of this embodiment, the exhaust gas abnormality determination unit 73 determines an abnormality in the exhaust gas E1 when the exhaust gas pressure, which is exhaust gas information acquired and stored by the exhaust gas information storage unit 72, exceeds a predetermined value. As a result, the control unit 70 can detect abnormalities on the abatement device 80 side, such as a failure of the damper 42 or the induced draft fan 44 or a blockage of the abatement device 80. Furthermore, the exhaust gas abnormality control unit 74 can suitably control each part in response to the exhaust gas abnormality being caused by a problem on the abatement device 80 side.

[0072] (5) In this embodiment, the boiler system 1 may perform pipe purging control in the combustion stop control of the boiler 10 by supplying purge gas G1 from the purge gas supply line L600 to purge the piping of the ammonia fuel supply line L200. This allows the ammonia fuel F2 remaining in the piping of the ammonia fuel supply line L200 to be discharged into the furnace and washed with water in the economizer 55 together with the combustion air A1 or exhaust gas. Therefore, the boiler system 1 can more effectively remove ammonia contained in the gas remaining in the piping and suppress the discharge of ammonia outside the system to within an acceptable range.

[0073] (Second Embodiment) Figure 5 is a diagram illustrating the boiler system 2 of the second embodiment. The boiler system 2 of the second embodiment is similar in form to the boiler system 1 of the first embodiment, except that it includes a branch exhaust gas line L410 that branches off from the exhaust gas line L400. Therefore, the same reference numerals are used for parts that perform the same functions as those of the first embodiment described above, and redundant explanations are omitted as appropriate. The boiler system 2 of this embodiment includes a boiler 10, a pollution control device 80, an exhaust gas line L400, and a boiler system control unit 90.

[0074] In this embodiment, the exhaust gas line L400 includes a branch exhaust gas line L410 that branches off from the exhaust gas line L400 at a branching point upstream of the damper 42. At least a portion of the exhaust gas E1 flowing through the exhaust gas line L400 flows through the branch exhaust gas line L410. The upstream side of the branch exhaust gas line L410 is connected to the exhaust gas line L400, and the downstream side is connected to a second exhaust gas line L430 located downstream of the pollution control device 80. The downstream side of the branch exhaust gas line L410 may be open to the atmosphere.

[0075] A damper 45 is provided in the branch exhaust gas line L410. The damper 45 is an opening / closing part that can open and close the flow path of the branch exhaust gas line L410, and the flow rate of exhaust gas E1 in the branch exhaust gas line L410 is adjusted by adjusting the opening degree of the damper. Specifically, the damper 45 is rotatably positioned between a closed state in which the flow path of the branch exhaust gas line L410 is blocked and an open state in which it rotates from this closed state to a predetermined angle (for example, 90 degrees) to open the flow path of the branch exhaust gas line L410. The damper 45 is communicated with the boiler system control unit 90 by wire or wireless and is controlled by signals transmitted from the boiler system control unit 90.

[0076] The boiler system control unit 90 controls the operation of the boiler system 2. The boiler system control unit 90, the control unit 70, and the abatement device control unit (not shown) are connected to each other via wired or wireless means, and communicate operational information and control instructions. As a result, the boiler system control unit 90 can, for example, instruct the abatement device control unit to open and close the damper 42 or to operate the induced draft fan 44.

[0077] Figure 6 is a time chart illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 in the boiler system 2 of the second embodiment when the ammonia concentration in the exhaust gas E1 exceeds a predetermined value. In Figure 6 and Figure 7 described later, time t1 is the time when the exhaust gas abnormality control unit 74 starts exhaust gas cleaning, and time t2 is the time when the exhaust gas abnormality control unit 74 finishes exhaust gas cleaning.

[0078] If, due to an abnormality on the boiler 10 side, the ammonia concentration in the exhaust gas E1 stored in the exhaust gas information storage unit 72 exceeds a predetermined value (the reference value for the ammonia concentration in the exhaust gas stored in the storage unit 71), and the exhaust gas abnormality determination unit 73 determines that the exhaust gas E1 is abnormal due to an abnormality on the boiler 10 side, the exhaust gas abnormality control unit 74 performs exhaust gas cleaning control and combustion stop control as exhaust gas abnormality control. In this embodiment, when an abnormality in exhaust gas E1 caused by a malfunction on the boiler 10 side is detected, the exhaust gas cleaning control includes not only the exhaust gas cleaning control for exhaust gas abnormalities caused by a malfunction on the boiler 10 side as described in the first embodiment, but also the control of opening and closing the damper 45 of the branch exhaust gas line L410. Furthermore, in this embodiment, when an abnormality in exhaust gas E1 caused by a malfunction on the boiler 10 side is detected, the combustion stop control is the same as the combustion stop control for exhaust gas abnormalities caused by a malfunction on the boiler 10 side as described in the first embodiment.

[0079] The exhaust gas abnormality control unit 74 transmits to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the boiler 10 side. Upon receiving this, the boiler system control unit 90 maintains the closure of the damper 45 on the branch exhaust gas line L410. Upon receiving this, the boiler system control unit 90 also instructs the abatement device control unit to open the damper 42 and continue operating the induced draft fan 44 as part of the exhaust gas cleaning control. Upon receiving this, the abatement device control unit continues to open the damper 42 and continue operating the induced draft fan 44. Therefore, exhaust gas E1 is introduced from the exhaust gas line L400 to the abatement device 80, and the abatement device 80 removes the ammonia contained in the exhaust gas E1 and discharges it.

[0080] The exhaust gas abnormality control unit 74 sprays water from the water spraying unit 57 for a predetermined time, then stops the operation of the pump 51 and closes the shut-off valve V56, ending the exhaust gas cleaning (time t2). The exhaust gas abnormality control unit 74 also stops the operation of the blower 31. As a result, the boiler 10 stops operating. Furthermore, the control unit 70 transmits the shutdown of the boiler 10 to the abatement device control unit. Upon receiving this, the abatement device control unit closes the damper 42, stops the operation of the induced draft fan 44, and stops the operation of the abatement device 80. As a result, the boiler system 2 stops operating. Alternatively, the control unit 70 may transmit the shutdown of the boiler 10 to the boiler system control unit 90, and the boiler system control unit 90 may instruct the abatement device control unit to close the damper 42, stop the operation of the induced draft fan 44, and stop the operation of the abatement device 80.

[0081] Figure 7 is a time chart illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 in the boiler system 2 of the second embodiment when the exhaust gas pressure exceeds a predetermined value. If the exhaust gas pressure, which is exhaust gas information stored in the exhaust gas information storage unit 72, exceeds a predetermined value (a reference value for exhaust gas pressure stored in the storage unit 71), and the exhaust gas abnormality determination unit 73 determines that the exhaust gas E1 is abnormal due to an abnormality on the abatement device 80 side, the exhaust gas abnormality control unit 74 performs exhaust gas cleaning control and combustion stop control as exhaust gas abnormality control. In this embodiment, the exhaust gas cleaning control in the event of an exhaust gas abnormality caused by a malfunction on the abatement device 80 side includes, in addition to the exhaust gas cleaning control in the event of an exhaust gas abnormality caused by a malfunction on the abatement device 80 side as described in the first embodiment, the opening and closing of the damper 45 of the branch exhaust gas line L410. Furthermore, in this embodiment, the timing of stopping the blower 31 in the event of an exhaust gas abnormality caused by a malfunction on the abatement device 80 side differs from that of the first embodiment.

[0082] The exhaust gas abnormality control unit 74 starts operating the pump 51 as exhaust gas cleaning control, opens the shut-off valve V56 of the second water supply line L520, and starts supplying water W2 from the second water supply line L520 to the water spraying unit 57. As a result, water spraying by the economizer 55 from the water spraying unit 57 begins (time t1).

[0083] Furthermore, the exhaust gas abnormality control unit 74 performs combustion stop control to stop the combustion of the boiler 10 at the same time as the start of exhaust gas cleaning. In this embodiment, the exhaust gas abnormality control unit 74, as part of the combustion stop control, continues to operate the blower 31 even after the combustion of the boiler 10 has stopped, supplying air A1 to the boiler 10. At this time, the exhaust gas abnormality control unit 74 controls the damper 33 and inverter 32, which are air flow rate adjustment units, to set the flow rate of air A1 circulating in the air supply line L300 to an exhaust gas abnormality air flow rate that is lower than the flow rate during combustion of the boiler 10. Since air A1 at the exhaust gas abnormality air flow rate is supplied to the boiler 10 by the blower 31, the ammonia-containing gas in the burner 12 and boiler body 11 is sent to the economizer 55 at a lower speed than during combustion along with the air A1, and the residence time in the economizer 55 is extended. As a result, the boiler system 1 can more effectively remove ammonia by water spraying.

[0084] Furthermore, the exhaust gas abnormality control unit 74 transmits to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the abatement device 80 side. Upon receiving this, the boiler system control unit 90 closes the damper 42 and opens the damper 45 as follows, and discharges the exhaust gas through the branch exhaust gas line L410. The boiler system control unit 90 opens the damper 45 as part of the exhaust gas cleaning control. This allows the boiler system 2 to discharge the exhaust gas E1, from which ammonia has been removed by water spraying, through the branch exhaust gas line L410. Furthermore, as part of the exhaust gas cleaning control, the boiler system control unit 90 instructs the abatement device control unit to close the damper 42 and stop the induced draft fan 44. Upon receiving this instruction, the abatement device control unit closes the damper 42, stops the operation of the induced draft fan 44, stops the introduction of exhaust gas E1 into the abatement device 80, and stops the operation of the abatement device 80. Furthermore, the exhaust gas abnormality control unit 74 may transmit a message to the boiler system control unit 90 indicating the start of exhaust gas cleaning control due to an abnormality on the abatement device 80 side, after a predetermined time has elapsed since the start of exhaust gas cleaning.

[0085] The exhaust gas abnormality control unit 74 sprays water from the water spraying unit 57 for a predetermined time, then stops the operation of the pump 51 and closes the shut-off valve V56, thereby ending the exhaust gas cleaning (time t2). The exhaust gas abnormality control unit 74 also stops the operation of the blower 31. As a result, the boiler 10 stops operating. Furthermore, the control unit 70 transmits a signal to the boiler system control unit 90 that the boiler 10 has been shut down. Upon receiving this signal, the boiler system control unit 90 closes the damper 45 of the branch exhaust gas line L410. As a result, the boiler system 2 shuts down.

[0086] According to this embodiment, the boiler system 2 can shut down in a way that suppresses the discharge of ammonia to the outside of the system, whether the boiler system 10 is malfunctioning or the abatement device 80 is malfunctioning. Furthermore, according to this embodiment, the boiler system 2 can discharge ammonia-containing gas remaining in the piping and boiler body 11 to the outside of the system via the branch exhaust gas line L410 without causing it to accumulate in the boiler 10, and after removing the ammonia.

[0087] In this embodiment as well, in the combustion stop control of the boiler 10, pipe purging control may be performed by supplying purge gas G1 from the purge gas supply line L600 to purge the ammonia fuel supply line L200.

[0088] According to this embodiment, in addition to the above (1) to (5), the following effects can be achieved. (6) According to the boiler system 2 of this embodiment, if the exhaust gas pressure, which is exhaust gas information acquired and stored by the exhaust gas information storage unit 72, exceeds a predetermined value (a reference value of exhaust gas pressure stored in the storage unit 71), and the exhaust gas abnormality determination unit 73 determines that there is an abnormality in the exhaust gas E1 caused by an abnormality on the abatement device 80 side, the damper 42, which is the first opening / closing unit, is closed and the damper 45, which is the second opening / closing unit, is opened. As a result, even if an abnormality occurs on the abatement device 80 side, such as blockage of the abatement device 80, causing the exhaust gas pressure to exceed a predetermined value (standard value for exhaust gas pressure), exhaust gas E1 with ammonia removed can be discharged from the branch exhaust gas line L410. Therefore, the boiler system 2 can suppress the leakage of ammonia remaining in the boiler 10 into the environment from the exhaust gas line L400, etc.

[0089] (Third embodiment) Figure 8 is a diagram illustrating the boiler system 3 of the third embodiment. The boiler system 3 of the third embodiment is similar in form to the first embodiment, except that it includes a branch exhaust gas line L410 that branches off from the exhaust gas line L400, and the boiler 30 injects steam S2 into the economizer 55. Therefore, the same reference numerals are used for parts that perform the same functions as those of the first and second embodiments described above, and redundant explanations are omitted as appropriate. The boiler 30 of this embodiment is a boiler that burns ammonia-containing fuel, similar to the boiler 10 shown in the first embodiment, and includes a boiler body 11, a burner 12, an economizer 55, a steam injection unit 92, a control unit 70, a first fuel supply line L100, an ammonia fuel supply line L200, an air supply line L300, a feedwater line L530, a purge gas supply line L600, a steam injection supply line L900, and the like. The boiler system 3 of this embodiment comprises the boiler 30 described above, a pollution control device 80, an exhaust gas line L400 including a branch exhaust gas line L410, and a boiler system control unit 90.

[0090] The water supply line L530 in this embodiment corresponds to the water supply line L500 and the first water supply line L510 shown in the first embodiment, etc. The injection steam supply line L900 supplies a portion of the steam (steam S2) generated in the boiler 30 to the steam injection unit 92. The injection steam supply line L900 is equipped with a steam shut-off valve V91, and its upstream side is connected to a steam supply line that supplies steam from the boiler 30 to a steam demand unit (not shown), while its downstream side is connected to the steam injection unit 92. The steam shut-off valve V91 is composed of a solenoid valve and opens and closes the flow path of the injection steam supply line L900 to supply or stop steam S2. The steam shut-off valve V91 is connected to the control unit 70 via wired or wireless communication and is controlled by signals transmitted from the control unit 70.

[0091] The steam injection unit 92 is a fluid injection unit that injects steam into the heat exchanger of the economizer 55. When steam is injected into the heat exchanger of the economizer 55 as in this embodiment, at least a portion of the steam S2 is cooled and condensed within the economizer 55, and the water droplets, mist, or water film on the surface of the heat exchanger of the economizer 55 dissolve the ammonia contained in the gas passing through the economizer 55. The condensed water containing dissolved ammonia is discharged from the blowdown discharge line L420 and treated by a treatment device (not shown).

[0092] Figure 9 is a time chart illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 when the ammonia concentration in the exhaust gas E1 exceeds a predetermined value in the boiler system 3 of the third embodiment. In Figure 9 and Figure 10 described later, time t1 is the time when the exhaust gas abnormality control unit 74 starts exhaust gas cleaning control, and time t2 is the time when the exhaust gas abnormality control unit 74 ends exhaust gas cleaning control.

[0093] If an abnormality occurs on the boiler 30 side and the ammonia concentration in the exhaust gas E1 stored in the exhaust gas information storage unit 72 exceeds a predetermined value (a reference value for the ammonia concentration in the exhaust gas stored in the storage unit 71), and the exhaust gas abnormality determination unit 73 determines that the exhaust gas E1 is abnormal due to an abnormality on the boiler 30 side, the exhaust gas abnormality control unit 74 performs exhaust gas abnormality control, which includes combustion stop control of the boiler 30 and exhaust gas cleaning control, which involves injecting steam S2 from the steam injection unit 92 to the economizer 55. In this embodiment, the combustion stop control in the event of an exhaust gas abnormality caused by an abnormality on the boiler 30 side is the same as in the first and second embodiments.

[0094] The exhaust gas abnormality control unit 74 opens the steam shut-off valve V91 of the injection steam supply line L900 as exhaust gas cleaning control and starts supplying steam S2 to the steam injection unit 92. This starts exhaust gas cleaning by injecting steam S2 from the steam injection unit 92 to the economizer 55 (time t1). At least a portion of the steam S2 is cooled and condensed in the economizer 55, and ammonia in the exhaust gas E1 dissolves in the water droplets, mist, or water film on the heat exchanger of the economizer 55 of this condensed water.

[0095] Simultaneously with the start of exhaust gas cleaning, the exhaust gas abnormality control unit 74 performs combustion stop control to stop the combustion of the boiler 30. Furthermore, as part of the combustion stop control, the exhaust gas abnormality control unit 74 continues to operate the blower 31 even after the combustion of the boiler 30 has stopped, and controls the damper 33 and inverter 32 to supply air A1 to the boiler 30 at an exhaust gas abnormality air flow rate that is lower than the flow rate during combustion of the boiler 30. As a result, the ammonia-containing gas in the burner 12 and boiler 11 is sent to the economizer 55 at a slower speed than during combustion, along with the air A1, and the residence time in the economizer 55 is extended. Therefore, the boiler system 3 can more effectively remove ammonia by injecting steam S2.

[0096] Furthermore, the exhaust gas abnormality control unit 74 transmits to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the boiler 10 side. Upon receiving this, the boiler system control unit 90 closes the damper 42 and opens the damper 45 as follows, and discharges the exhaust gas through the branch exhaust gas line L410. As part of the exhaust gas cleaning control, the boiler system control unit 90 opens the damper 45 of the branch exhaust gas line L410. This prevents steam S2 from flowing into the abatement device 80, and allows the boiler system 3 to discharge the exhaust gas E1, from which ammonia has been removed, from the branch exhaust gas line L410. Furthermore, as part of the exhaust gas cleaning control, the boiler system control unit 90 instructs the abatement device control unit (not shown) to stop the damper 42 and the induced draft fan 44. Based on this, the abatement device control unit closes the damper 42, stops the operation of the induced draft fan 44, stops the introduction of exhaust gas E1 into the abatement device 80, and stops the operation of the abatement device 80.

[0097] The exhaust gas abnormality control unit 74 injects steam S2 from the steam injection unit 92 for a predetermined time, then closes the steam shut-off valve V91, ending the exhaust gas cleaning (time t2). The exhaust gas abnormality control unit 74 also stops the operation of the blower 31. As a result, the boiler 30 stops operating. Furthermore, the control unit 70 transmits a signal to the boiler system control unit 90 that the boiler 30 has been shut down. Upon receiving this signal, the boiler system control unit 90 closes the damper 45 on the branch exhaust gas line L410. As a result, the boiler system 3 shuts down.

[0098] Figure 10 is a time chart illustrating the exhaust gas cleaning control of the exhaust gas abnormality control unit 74 and the control of the blower 31 in the boiler system 3 of the third embodiment when the exhaust gas pressure exceeds a predetermined value. If the exhaust gas pressure stored in the exhaust gas information storage unit 72 exceeds a predetermined value (the reference value of exhaust gas pressure stored in the storage unit 71) due to a malfunction on the abatement device 80 side, and the exhaust gas abnormality determination unit 73 determines that the exhaust gas E1 is abnormal due to a malfunction on the abatement device 80 side, the exhaust gas abnormality control unit 74 performs exhaust gas abnormality control, which includes combustion stop control of the boiler 30 and exhaust gas cleaning control, which involves injecting steam S2 from the steam injection unit 92 to the economizer 55. In this embodiment, the combustion stop control in the event of an exhaust gas abnormality caused by a malfunction on the abatement device 80 side is the same as in the second embodiment, but the timing of stopping the blower 31 is different from that of the first embodiment.

[0099] The exhaust gas abnormality control unit 74 opens the steam shut-off valve V91 of the injection steam supply line L900 as exhaust gas cleaning control and starts supplying injection steam S2 to the steam injection unit 92. This starts exhaust gas cleaning by injecting steam S2 from the steam injection unit 92 to the economizer 55 (time t1).

[0100] Simultaneously with the start of exhaust gas cleaning, the exhaust gas abnormality control unit 74 performs combustion stop control to stop the combustion of the boiler 30. Also, as in the second embodiment, as part of the combustion stop control, the exhaust gas abnormality control unit 74 continues to operate the blower 31 even after the combustion of the boiler 10 has stopped, and controls the damper 33 and inverter 32 to supply air A1 to the boiler 30 at an exhaust gas abnormality air flow rate that is lower than the flow rate during combustion of the boiler 30. As a result, the boiler system 3 can more effectively remove ammonia by injecting steam S2.

[0101] Furthermore, the exhaust gas abnormality control unit 74 transmits to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the abatement device 80 side. Upon receiving this, the boiler system control unit 90 closes the damper 42 and opens the damper 45 as follows, and discharges the exhaust gas through the branch exhaust gas line L410. As part of the exhaust gas cleaning control, the boiler system control unit 90 instructs the abatement device control unit (not shown) to stop the damper 42 and the induced draft fan 44. Upon receiving this instruction, the abatement device control unit closes the damper 42, stops the operation of the induced draft fan 44, stops the introduction of exhaust gas E1 into the abatement device 80, and stops the operation of the abatement device 80. Furthermore, the boiler system control unit 90 opens the damper 45 of the branch exhaust gas line L410 as part of the exhaust gas cleaning control. This allows the boiler system 3 to safely discharge the exhaust gas E1, from which ammonia has been removed by steam injection, out of the system through the branch exhaust gas line L410.

[0102] The exhaust gas abnormality control unit 74 injects steam S2 from the steam injection unit 92 for a predetermined time, then closes the steam shut-off valve V91 of the steam injection supply line L900, ending the exhaust gas cleaning (time t2). The exhaust gas abnormality control unit 74 also stops the operation of the blower 31. As a result, the boiler 30 stops operating. Furthermore, the control unit 70 transmits a signal to the boiler system control unit 90 that the boiler 10 has been shut down. Upon receiving this signal, the boiler system control unit 90 closes the damper 45 of the branch exhaust gas line L410. As a result, the boiler system 3 shuts down.

[0103] According to this embodiment, in the event of an abnormal shutdown due to a malfunction on the boiler 30 side, or an abnormal shutdown due to a malfunction on the aqueduct 80 side, the boiler system 3 can shut down while suppressing the discharge of ammonia to the outside of the system. Furthermore, the boiler system 3 can safely discharge the ammonia-containing gas remaining in the boiler 30 through the branch exhaust gas line L410 without allowing it to accumulate in the boiler 30, and after removing the ammonia.

[0104] In this embodiment as well, in the combustion stop control of the boiler 30, pipe purging control may be performed by supplying purge gas G1 from the purge gas supply line L600 to purge the ammonia fuel supply line L200.

[0105] According to this embodiment, in addition to the effects of (2) to (6) above, the following effects can be achieved. (7) According to the boiler system 3 of this embodiment, the exhaust gas abnormality control unit 74 stops the combustion of the boiler 30 and injects steam from the steam injection unit 92, which is a fluid injection unit, to the economizer 55, based on the determination result of the exhaust gas abnormality determination unit 73. This allows the economizer 55 to cool and condense the steam S2, and dissolve any remaining ammonia in the boiler 30 into the water droplets, mist, or water film on the heat exchange surface of the economizer 55. Therefore, even if a malfunction occurs in the boiler system, the boiler system 3 can prevent ammonia leakage by processing the ammonia and suppress ammonia emissions to an acceptable level. Furthermore, the boiler system 3 can remove ammonia from the gas present in the boiler 30, and even if the boiler 30 does not shut down properly, it can perform a shutdown that suppresses the leakage of ammonia outside the system.

[0106] (Transformed form) The present invention is not limited to the embodiments described above, and various modifications and changes are possible, all of which fall within the scope of the present invention. In each embodiment, examples were shown in which boilers 10 and 30 co-fire ammonia fuel F2 and first fuel F1. However, the invention is not limited to these examples, and it is also possible to burn only ammonia fuel F2, or to burn ammonia decomposition gas as the ammonia fuel F2.

[0107] In each embodiment, the exhaust gas abnormality determination unit 73 was described using an example where the standard value of ammonia concentration in the exhaust gas is used as one of the exhaust gas information standard values ​​stored in the storage unit 71. However, it is not limited to this, and the standard value of unburned hydrogen concentration (ammonia decomposition products) in exhaust gas E1 may be used as the exhaust gas information standard value, or the standard values ​​of the amount of NOx or N2O (nitrous oxide) in the exhaust gas may be used. In the case of co-firing of ammonia and hydrocarbon fuel, the standard value of the amount of CO (carbon monoxide) in the exhaust gas may be used.

[0108] In each embodiment, the exhaust gas abnormality determination unit 73 was described as also determining whether the abnormality in exhaust gas E1 is due to an abnormality on the boiler 10,30 side or an abnormality on the pollution control device 80 side. However, the description is not limited to this, and if the exhaust gas abnormality determination unit 73 determines that there is an abnormality in exhaust gas E1, the exhaust gas abnormality control unit 74 may, based on the determination of the exhaust gas abnormality determination unit 73 (whether the abnormality in exhaust gas E1 is due to an abnormality in the ammonia concentration in exhaust gas E1 or an abnormality in exhaust gas pressure), perform combustion stop control or exhaust gas cleaning control according to the abnormality on the boiler 10,30 side if the abnormality is due to an abnormality in the ammonia concentration in exhaust gas E1, and perform combustion stop control or exhaust gas cleaning control according to the abnormality on the pollution control device 80 side if the abnormality is due to an abnormality in exhaust gas pressure.

[0109] In each embodiment, the exhaust gas abnormality control unit 74 is shown to perform combustion stop control simultaneously with the start of exhaust gas cleaning. However, it is not limited to this, and combustion stop control may be performed a predetermined time after the start of exhaust gas cleaning.

[0110] In each embodiment, pipe purging control may be performed by supplying purge gas G1 from the purge gas supply line L600 to purge the ammonia fuel supply line L200. However, it is also possible to control whether or not to perform pipe purging and the duration of purging based on the determination result of the exhaust gas abnormality determination unit 73, for example, by performing pipe purging control when the determination result of the exhaust gas abnormality determination unit 73 indicates a minor abnormality, and not performing pipe purging control when the determination result of the exhaust gas abnormality determination unit 73 indicates a severe abnormality.

[0111] In each embodiment, the exhaust gas abnormality control unit 74 controls the damper 33 and inverter 32, which are air flow rate adjustment units, to set the flow rate of air A1 supplied to the burner 12 to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion of the boiler 10, when the exhaust gas abnormality determination unit 73 determines that there is an abnormality in the exhaust gas E1 due to an abnormality on the boiler 10, 30 side. However, the exhaust gas abnormality control unit 74 is not limited to this, and may also stop the blower 31 at the same time as the combustion of the boiler 10, 30 stops.

[0112] In the second and third embodiments, the exhaust gas abnormality control unit 74 transmitted to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the boiler 10 side. However, the exhaust gas abnormality control unit 74 may also transmit to the boiler system control unit 90 and the abatement device control unit the start of exhaust gas cleaning control due to an abnormality on the boiler 10 side. Upon receiving this, the abatement device control unit continues to open the damper 42 and operate the induced draft fan 44.

[0113] In the third embodiment, the boiler system 3 may perform both the injection of steam S2 and the spraying of water W2 to the economizer 55.

[0114] In the third embodiment, the exhaust gas abnormality control unit 74 transmits to the boiler system control unit 90 the start of exhaust gas cleaning control due to an abnormality on the abatement device 80 side, but is not limited to this. The dampers 42, 45 and induced draft fan 44 may also be configured to be directly controlled by the control unit 70.

[0115] In each embodiment, the exhaust gas abnormality control unit 74 was described as transmitting to the abatement device control unit and boiler system control unit 90 (not shown) the start of exhaust gas cleaning control due to an abnormality on the boiler 10,30 side or the start of exhaust gas cleaning control due to an abnormality on the abatement device 80 side. However, the invention is not limited to this, and the control unit 70 may transmit when the ammonia concentration in the exhaust gas E1 exceeds a predetermined value (reference value for ammonia concentration in exhaust gas) or when the exhaust gas pressure exceeds a predetermined value (reference value for exhaust gas pressure), or the control unit 70 may transmit each signal.

[0116] In each embodiment, an exhaust gas information detection unit (not shown) for detecting exhaust gas information relating to exhaust gas may be provided outside the boiler systems 1, 2, and 3. For example, as the exhaust gas information detection unit, an environmental ammonia concentration monitoring unit (not shown) for monitoring the ammonia concentration in the surrounding environment of the boiler systems 1, 2, and 3 may be provided, and the exhaust gas information storage unit 72 may acquire and store the ammonia concentration in the environment transmitted by the environmental ammonia concentration monitoring unit as exhaust gas information.

[0117] In each embodiment, the exhaust gas information storage unit 72 may be configured to temporarily store exhaust gas information for processing signals acquired from the exhaust gas pressure sensor 41, the exhaust gas ammonia sensor 46, and the aforementioned exhaust gas information detection unit. Alternatively, the exhaust gas information storage unit 72 may be configured as part of the exhaust gas abnormality determination unit 73.

[0118] The embodiments and variations of this invention can be used in combination as appropriate, but a detailed explanation is omitted. Furthermore, the present invention is not limited to the embodiments described above.

[0119] Furthermore, since the present invention promotes the use of ammonia as a fuel that does not emit carbon dioxide, it can contribute, for example, to United Nations Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable and modern energy." [Explanation of symbols]

[0120] 1,2,3 Boiler System 10,30 boilers 11 Can body 12 burners 31 Blower 32. Inverter (Airflow Adjustment Unit) 33. Damper (airflow adjustment section) 41. Exhaust gas pressure sensor (exhaust gas pressure detection unit) 42 Damper (first opening / closing section) 45 Damper (second opening / closing section) 46. ​​Exhaust gas ammonia sensor (exhaust gas ammonia detection unit) 55 Economizer 57 Spraying section (fluid injection section) 92. Steam injection section (fluid injection section) 70 Control Unit 72 Exhaust gas information storage unit 73 Exhaust gas abnormality detection unit 74 Exhaust gas abnormality control unit L100 Fuel supply line 1 L200 Ammonia Fuel Supply Line L300 Air Supply Line L400 exhaust gas line L410 Branch Exhaust Gas Line L500 Water supply line L510, L530 1st water supply line L520 Second water supply line (fluid supply line) L600 Purge Gas Supply Line L900 Injection Steam Supply Line (Fluid Supply Line)

Claims

1. A boiler that burns fuel containing ammonia, A decontamination device for removing ammonia contained in the exhaust gas of the boiler, An exhaust gas line for introducing the exhaust gas generated in the boiler to the pollution control device, A boiler system comprising, The aforementioned boiler is A burner for burning the aforementioned fuel, an ammonia fuel supply line that supplies the fuel to the boiler, A boiler body for recovering heat from combustion gases generated by the combustion of the aforementioned fuel, An economizer that further recovers heat from the combustion gas after heat has been recovered in the aforementioned boiler, The economizer is provided with a fluid injection unit that performs at least one of either water spraying or steam injection, A fluid supply line that supplies water or steam to the fluid injection unit, A control unit that controls the operation of the boiler, Equipped with, The control unit comprises an exhaust gas information storage unit, an exhaust gas abnormality determination unit, and an exhaust gas abnormality control unit. The exhaust gas information storage unit acquires and stores exhaust gas information relating to the exhaust gas flowing through the exhaust gas line. The exhaust gas abnormality determination unit determines whether the exhaust gas is abnormal based on the exhaust gas information stored in the exhaust gas information storage unit. The exhaust gas abnormality control unit, based on the determination result of the exhaust gas abnormality determination unit, The boiler combustion is stopped, and At least one of the following is performed: spraying water or injecting steam from the fluid injection unit to the economizer. Boiler system.

2. A first opening / closing unit that opens and closes the exhaust gas line, A branch exhaust gas line is provided, which branches off from the upstream side of the first opening / closing section of the exhaust gas line, and through which at least a portion of the exhaust gas flows. A second opening / closing unit is provided in the branch exhaust gas line and is capable of opening and closing the flow path of the branch exhaust gas line, A boiler system control unit that controls the operation of the boiler system, Equipped with, The boiler system control unit, when the exhaust gas abnormality determination unit determines that there is an abnormality in the exhaust gas, closes the first opening / closing section and opens the second opening / closing section, and discharges the exhaust gas through the branch exhaust gas line. The boiler system according to claim 1.

3. The boiler is equipped with a purge gas supply line that supplies purge gas to the ammonia fuel supply line. The exhaust gas abnormality control unit, when the exhaust gas abnormality determination unit determines that there is an abnormality in the exhaust gas, The combustion of the boiler is stopped, and, The ammonia fuel supply line is purged by supplying purge gas from the purge gas supply line, and, At least one of the following is performed: water is sprayed or steam is injected from the fluid injection unit onto the economizer. The boiler system according to claim 1.

4. The aforementioned boiler is A fan that blows out air, An air supply line that supplies the air blown out by the blower to the burner, An air flow rate adjustment unit that adjusts the flow rate of the aforementioned air, Equipped with, The exhaust gas abnormality control unit, when the exhaust gas abnormality determination unit determines that an abnormality has occurred in the exhaust gas during ammonia combustion of the boiler, controls the air flow rate adjustment unit to set the air flow rate to an exhaust gas abnormality air flow rate that is less than the flow rate during combustion of the boiler. The boiler system according to claim 1.

5. The exhaust gas pressure detection unit detects the pressure of the exhaust gas in the exhaust gas line, The exhaust gas information storage unit acquires and stores the detection result of the exhaust gas pressure detection unit as exhaust gas information. The exhaust gas abnormality determination unit determines an abnormality in the exhaust gas when the detection result of the exhaust gas pressure detection unit, which is the exhaust gas information, exceeds a predetermined value. The boiler system according to claim 1.

6. The exhaust gas ammonia detection unit is provided to detect ammonia in the exhaust gas of the exhaust gas line, The exhaust gas information storage unit acquires and stores the detection result of the exhaust gas ammonia detection unit as exhaust gas information. The exhaust gas abnormality determination unit determines an abnormality in the exhaust gas when the detection result of the exhaust gas ammonia detection unit, which is the exhaust gas information, exceeds a predetermined value. The boiler system according to claim 1.

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