Boiler equipment

Abstract

To provide a boiler device in which adjustment control for restricting combustion air amount when hydrogen mixed fuel gas obtained by mixing hydrogen fuel with fuel gas is burned is added.SOLUTION: A boiler device 1 includes a control section 71 and an oxygen concentration detection section 81 for detecting an oxygen concentration of exhaust gas. The control section 71 includes: a hydrogen mixing information acquisition section 716 for acquiring hydrogen mixing information on hydrogen mixed fuel gas; and a combustion air amount correction section 717 for correcting a flow rate of combustion air by using the hydrogen mixing information on the hydrogen mixed fuel gas acquired by the hydrogen mixing information acquisition section 716. The control section 71 adjusts a flow rate of the hydrogen mixed fuel gas in accordance with the flow rate of the combustion air corrected by the combustion air amount correction section 717, and then, adjusts the flow rate of the hydrogen mixed fuel gas so that the oxygen concentration of the exhaust gas detected by the oxygen concentration detection section 81 becomes a specified value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a boiler device that controls the flow rate of fuel gas in accordance with the flow rate of combustion air based on a load instruction, measures the O2 concentration in the exhaust gas, and performs constant O2 control to control the fuel flow rate so that the O2 concentration in the exhaust gas remains constant regardless of changes in the external environment, etc., and that can burn at a predetermined thermal output even if the mixture ratio of hydrogen fuel and other gas fuel in the gas fuel changes. [Background technology]

[0002] Boiler systems have been known in the past that burn a mixture of fuel gas and combustion air in a predetermined ratio to heat water and generate steam. In this type of boiler system, the flow rate of the fuel gas is adjusted using a flow control valve or the like in accordance with the amount of combustion air supplied so that the air ratio, which is the ratio of the theoretical air volume to the amount of air supplied to the boiler, is constant. The air ratio is a value set by the boiler equipment, and if the air ratio fluctuates, for example, there is a possibility that combustion efficiency will decrease due to heat loss caused by excess air, or that energy loss will increase due to incomplete combustion, so it is desirable to maintain it within the set range (or constant) as much as possible. When the mass flow rate of fuel gas fluctuates due to temperature or pressure fluctuations, even if the volumetric flow rate of the fuel gas is constant, the theoretical amount of combustion air required to combust the fuel gas changes, causing the air ratio to fluctuate. For this reason, in order to deal with fluctuations in the air ratio, constant O2 control has been put into practical use, in which combustion is performed at a predetermined air ratio by feedback-controlling the fuel gas flow rate based on the oxygen concentration in the exhaust gas from the boiler equipment, and various technologies have been disclosed that accurately reflect the combustion state of the boiler in the air ratio (see, for example, Patent Document 1).

[0003] Furthermore, feedback control of the air-fuel mixture based on the oxygen concentration of the exhaust gas may result in a time lag when the air-fuel mixture is controlled to the desired state. For this reason, a technique is known that enables the air-fuel mixture to be quickly controlled to the desired state when a fluctuation occurs in the air-fuel mixture supplied to the burner. Specifically, a technique is disclosed in which the oxygen concentration of the exhaust gas after a predetermined time has elapsed (referred to as a predicted oxygen concentration) is calculated based on the rate of change of the oxygen concentration of the exhaust gas, and an oxygen concentration deviation is calculated based on the predicted oxygen concentration and a target oxygen concentration, thereby feedback controlling the air-fuel mixture (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-008803 [Patent Document 2] Patent Publication No. 2021-046969 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, with the recent rise in environmental awareness, attempts are being made to reduce carbon dioxide emissions associated with combustion by burning hydrogen fuel in boiler equipment, etc. Therefore, even in boiler equipment that burns city gas to heat water and generate steam, for example, it is desirable to reduce carbon dioxide emissions associated with combustion by mixing hydrogen fuel with city gas and burning it. For example, when city gas is mixed with hydrogen gas as a hydrogen fuel and burned in a boiler device that applies constant O2 control, the theoretical air volume of city gas is about four times that of hydrogen gas, so the oxygen concentration in the exhaust gas rises and constant O2 control, which increases the flow rate of the mixed gas, is activated, controlling the oxygen concentration of the exhaust gas to a specified range (value).On the other hand, when city gas and hydrogen gas are mixed, the theoretical air volume and the rate of change in thermal output differ, so in areas where the hydrogen content of the mixed gas is high, the increase in thermal output beyond the specified value causes excessive thermal load on the boiler body, increasing the risk of the boiler body puncturing. For this reason, when hydrogen fuel is mixed with city gas and burned, it is desirable to stably control the heat output to a predetermined value in response to a combustion command even if the mixture ratio of hydrogen fuel fluctuates.

[0006] The present invention aims to provide a boiler device that controls the flow rate of fuel gas in accordance with the flow rate of combustion air based on load instructions, measures the O2 concentration in the exhaust gas, and performs constant O2 control to control the fuel flow rate so that the O2 concentration in the exhaust gas remains constant regardless of changes in the external environment, etc., and that can burn at a specified thermal output even if the mixture ratio of hydrogen fuel and other gas fuel in the gas fuel changes. [Means for solving the problem]

[0007] The present invention provides Boiler and a fuel supply line for supplying fuel gas mixed with hydrogen fuel to the boiler; a flow rate adjusting valve disposed in the fuel supply line and capable of adjusting a flow rate of the fuel gas; an air supply line for supplying combustion air to the boiler; an air flow rate detection unit that detects the flow rate of the combustion air flowing through the air supply line; an exhaust gas discharge section that discharges exhaust gas generated by combustion of the fuel gas from the boiler; an oxygen concentration detection unit disposed in the exhaust gas discharge unit and configured to detect an oxygen concentration of the exhaust gas; a control unit for controlling the amounts of fuel gas and combustion air supplied to the boiler; Equipped with The control unit a fuel gas primary regulation function unit that controls the flow rate of the fuel gas in accordance with the flow rate of combustion air supplied from the air supply line based on a load instruction; a fuel gas secondary regulation function unit that controls the flow rate regulation valve so that the oxygen concentration of the exhaust gas detected by the oxygen concentration detection unit becomes a predetermined value; a hydrogen mixture information acquisition unit that acquires hydrogen mixture information of the hydrogen-mixed fuel gas; a combustion air amount correction unit that corrects the flow rate of the combustion air based on the hydrogen mixture information of the hydrogen-mixed fuel gas acquired by the hydrogen mixture information acquisition unit; The present invention relates to a boiler apparatus comprising:

[0008] The boiler apparatus further includes a fuel gas flow rate detection unit that detects a flow rate of the fuel gas flowing through the fuel supply line, The hydrogen mixing information acquisition unit It is preferable to estimate hydrogen mixing information based on the flow rate of the fuel gas detected by the fuel gas flow rate detection unit after the adjustment of the fuel gas so that the oxygen concentration of the exhaust gas becomes a predetermined value set based on the flow rate of the combustion air.

[0009] The hydrogen mixing information acquisition unit further It is preferable that hydrogen mixture information be calculated based on the amount of hydrogen fuel input to the fuel gas.

[0010] The hydrogen mixing information acquisition unit further It is preferable that the hydrogen mixture information is obtained by receiving a signal related to the hydrogen mixture information. [Effects of the Invention]

[0011] According to the present invention, a boiler device can be provided that controls the flow rate of fuel gas in accordance with the flow rate of combustion air based on load instructions, measures the O2 concentration in the exhaust gas, and controls the fuel flow rate so that the O2 concentration in the exhaust gas remains constant regardless of changes in the external environment, etc., and that can burn at a predetermined thermal output even if the mixture ratio of hydrogen fuel and other gas fuel in the gas fuel changes. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram schematically illustrating an embodiment of a boiler apparatus according to the present invention. [Figure 2] FIG. 2 is a functional block diagram showing the configuration of a control unit according to the present embodiment. [Figure 3]10 is a table showing the relationship between the flow rate of hydrogen-mixed fuel gas and the hydrogen mixing ratio. [Figure 4] 1 is a table showing an example of the relationship between the amount of combustion air and the hydrogen mixing ratio. [Figure 5] FIG. 2 is a diagram showing a process flow when fuel gas is combusted in a boiler device according to a required load according to the present invention. [Figure 6A] FIG. 2 is a diagram showing a process flow of feedback control of the flow rate of fuel gas based on the oxygen concentration of exhaust gas according to the present invention. [Figure 6B] FIG. 4 is a diagram showing a processing flow for calculating a corrected combustion air amount based on the hydrogen mixing ratio of the mixed fuel gas according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, preferred embodiments of the boiler apparatus of the present invention will be described with reference to the drawings. The boiler apparatus 1 of the first embodiment is a steam boiler that heats water to generate steam and supplies the steam to load equipment (not shown). In this specification, the term "line" is a general term for a line through which a fluid can flow, such as a flow path, a passage, or a pipe.

[0014] As shown in FIG. 1, the boiler apparatus 1 includes a boiler 2, a fuel supply unit 50 that supplies fuel gas to the boiler 2, a water supply line (not shown) that supplies water to the boiler 2, and a control device 70 that controls the supply amounts of fuel gas and combustion air, etc.

[0015] The boiler 2 comprises a boiler body 10, a blower 20 that sends combustion air into the boiler body 10, an air intake duct 30 that connects the boiler body 10 and the blower 20 and serves as an air supply line through which the combustion air flows, a damper 31 that serves as an air flow rate adjustment unit and is arranged in the air intake duct 30, a punched metal 32 that serves as a combustion air pressure reduction member, an air differential pressure sensor 33 that serves as an air flow rate detection unit, and an exhaust stack 80 that serves as an exhaust gas discharge unit through which the combustion gas (exhaust gas) discharged from the boiler body 10 flows.

[0016] The boiler body 10 includes a boiler housing 11, a plurality of water tubes 12, a lower header 13, an upper header 14, and a burner 15.

[0017] The boiler casing 11 constitutes the outer shape of the boiler body 10 and is formed in the shape of a rectangular parallelepiped that is rectangular in plan view. An air inlet 16 is formed in a first side surface 11a located at one end side of the boiler casing 11 in the longitudinal direction, and an exhaust port 17 is formed in a second side surface 11b located at the other end side of the boiler casing 11 in the longitudinal direction.

[0018] The plurality of water tubes 12 are arranged inside the boiler casing 11 so as to extend in the vertical direction, and are arranged at predetermined intervals in the longitudinal and width directions of the boiler casing 11.

[0019] The lower header 13 is disposed at the bottom of the boiler casing 11. The lower ends of the multiple water tubes 12 are connected to the lower header 13. The upper header 14 is disposed at the top of the boiler casing 11. The upper ends of the multiple water tubes 12 are connected to the upper header 14.

[0020] The burner 15 is disposed at the air inlet 16. The burner 15 burns a mixture of fuel gas and combustion air, heating the water in the water tubes 12 and generating steam.

[0021] Blower 20 is an air flow rate adjusting unit for adjusting the flow rate of combustion air, and includes blower body 21 having a fan and a motor for rotating the fan, and inverter 22 for increasing or decreasing the rotation speed of the fan (motor). Blower 20 sends combustion air into can body 10 by rotating the fan at a predetermined rotation speed according to the frequency input to inverter 22. Note that blower 20 can control the air flow rate by driving the fan at a rotation speed according to the frequency input to inverter 22.

[0022] In this embodiment, the flow rate of combustion air is set according to the required load from the load equipment (not shown). The blower 20 is controlled by the control device 70 via the inverter 22 so that the flow rate of the fuel air becomes the set flow rate. In this embodiment, hydrogen gas is exemplified as the hydrogen fuel, but the hydrogen fuel is not limited to this. For example, in addition to hydrogen gas, ammonia gas and a mixed gas of hydrogen, nitrogen, and ammonia obtained by decomposing ammonia may also be used. Furthermore, as will be described later, when hydrogen fuel is mixed with fuel gas to burn in the boiler device 1, the flow rate of fuel air is controlled by the control device 70 via the inverter 22 so as to be corrected based on the hydrogen mixing information of the fuel gas.

[0023] The air intake duct 30 is an air supply line that supplies combustion air to be mixed with fuel gas to the boiler 2. The upstream end of the air intake duct 30 is connected to the blower 20, and the downstream end is connected to the air intake port 16. The air intake duct 30 supplies the combustion air sent from the blower 20 to the boiler body 10.

[0024] The damper 31 is arranged to be rotatable between a closed state in which the flow path of the combustion air inside the air intake duct 30 is blocked, and an open state in which the damper 31 is rotated 90 degrees from the closed state and opens the flow path of the combustion air inside the air intake duct 30.

[0025] The perforated metal 32 is a metal plate with a plurality of through holes formed therein, and is a combustion air decompression member that decompresses the combustion air flowing through it. The perforated metal 32 is disposed downstream of the damper 31 inside the air intake duct 30. The perforated metal 32 decompresses the combustion air that has flowed through the damper 31 to the air intake duct 30.

[0026] As described above, the air differential pressure sensor 33 is an air flow rate detection unit for detecting the flow rate of combustion air. The air differential pressure sensor 33 detects the differential pressure between the pressure on the upstream side and the pressure on the downstream side of the perforated metal 32. The flow rate of the fuel air is calculated based on this differential pressure information. The air differential pressure sensor 33 is also electrically connected to the control device 70, and the control device 70 acquires the air differential pressure information detected by the air differential pressure sensor 33.

[0027] The exhaust pipe 80 is formed in a cylindrical shape and its base end is connected to the boiler body 10 (the exhaust port 17 formed in the boiler housing 11). Combustion gas (exhaust gas) generated in the boiler body 10 is discharged to the outside of the boiler body 10 through the exhaust pipe 80.

[0028] In this embodiment, an O2 sensor 81 serving as an oxygen concentration detector is disposed inside the exhaust stack 80. The O2 sensor 81 acquires the oxygen concentration of the exhaust gas. The O2 sensor 81 is electrically connected to the control device 70, and the control device 70 acquires the oxygen concentration of the exhaust gas based on the measurement value of the O2 sensor 81.

[0029] Next, we will explain the fuel supply unit 50 that supplies fuel to the boiler 2. The fuel supply unit 50 includes a fuel supply line 51, a fuel gas flow meter 52, an on-off valve 54, a governor 55, a flow control valve 56, a fuel gas temperature sensor 57, a fuel gas pressure sensor 58, an orifice 59, a fuel gas differential pressure sensor 60, and a nozzle 61.

[0030] The upstream side of fuel supply line 51 is connected to a fuel supply source (not shown), and the downstream side is connected to air intake duct 30. The downstream end of fuel supply line 51 is connected to air intake duct 30 downstream of the position where damper 31 is disposed. In this embodiment, the fuel gas flowing through the fuel supply line 51 is exemplified as city gas of fuel type 13A mixed with hydrogen gas as a hydrogen fuel. Specifically, city gas of fuel type 13A mixed with hydrogen gas as a hydrogen fuel is supplied to the fuel supply line 51. Note that this embodiment is not limited to city gas of fuel type 13A. Any fuel gas may be used.

[0031] The fuel gas flow meter 52 measures the flow rate of the fuel gas flowing through the fuel supply line 51. In this embodiment, the fuel gas flow meter 52 is disposed at the most upstream side of the fuel supply line 51. The fuel gas flow meter 52 is electrically connected to the control device 70. The control device 70 obtains the flow rate of the fuel gas based on the measurement value of the fuel gas flow meter 52.

[0032] The on-off valve 54 starts and stops the supply of fuel gas by opening and closing the fuel supply line 51. The on-off valve 54 in this embodiment is disposed downstream of the fuel gas flow meter 52 in the fuel supply line 51.

[0033] The governor 55 is a pressure adjusting means for suppressing abrupt pressure fluctuations that may occur when the pressure of the fuel gas flowing through the fuel supply line 51 increases instantaneously. The governor 55 in this embodiment is disposed downstream of the on-off valve 54 in the fuel supply line 51.

[0034] The flow rate control valve 56 adjusts the flow rate of the fuel gas flowing through the fuel supply line 51. The flow rate control valve 56 is configured to be able to adjust its opening. In this embodiment, the flow rate control valve 56 is disposed downstream of the governor 55 in the fuel supply line 51. The flow rate control valve 56 is electrically connected to the control device 70, and the control device 70 can adjust the opening of the flow rate control valve 56. In this embodiment, the control device 70 controls the aperture of the flow rate adjustment valve 56 so as to supply fuel gas at a flow rate corresponding to the flow rate of combustion air flowing through the air intake duct 30. Furthermore, as will be described later, when hydrogen gas as a hydrogen fuel is mixed into fuel gas to combust in the boiler apparatus 1, the control device 70 controls the aperture of the flow rate adjustment valve 56 so as to supply fuel gas at a flow rate corresponding to the flow rate of fuel air corrected based on hydrogen mixing information of the fuel gas.

[0035] The fuel gas pressure sensor 58 measures the pressure of the fuel gas flowing through the fuel supply line 51 downstream of the flow rate control valve 56. In this embodiment, the fuel gas pressure sensor 58 is disposed downstream of the fuel gas temperature sensor 57 in the fuel supply line 51. The fuel gas pressure sensor 58 is electrically connected to the control device 70, and the control device 70 acquires pressure information from the fuel gas pressure sensor 58.

[0036] The orifice 59 is a fuel gas decompression member that decompresses the fuel gas flowing through the fuel supply line 51. The orifice 59 of this embodiment is disposed downstream of the fuel gas pressure sensor 58 in the fuel supply line 51.

[0037] The fuel gas differential pressure sensor 60 is a fuel gas flow rate detection unit that detects the flow rate of the fuel gas. It detects the differential pressure between the upstream and downstream sides of the orifice 59. The flow rate of the fuel gas downstream of the flow control valve 56 is calculated based on this fuel gas differential pressure information. The fuel gas differential pressure sensor 60 is electrically connected to the control device 70, which acquires the fuel gas differential pressure information and calculates the fuel gas flow rate based on the fuel gas differential pressure information.

[0038] Nozzle 61 is disposed at the downstream end of fuel supply line 51 and ejects fuel gas into air intake duct 30. The fuel gas ejected from nozzle 61 is mixed with combustion air sent by blower 20, and this mixed gas is combusted by burner 15.

[0039] In this way, the fuel supply unit 50 is capable of supplying fuel gas to the boiler 2 (boiler body 10) through the fuel supply line 51 at an appropriate flow rate.

[0040] The control device 70 will now be described. The control device 70 controls the flow rate adjustment valve 56 and the blower 20 based on signals from the various electrically connected sensors. The control device 70 includes a control unit 71 that performs various controls to adjust the flow rate of combustion air and the flow rate of fuel gas, and a memory unit 72 that stores various information.

[0041] The control device 70 of the first embodiment controls the flow rate adjustment valve 56 by referring to the oxygen concentration of the exhaust gas in order to keep the air ratio constant. First, a brief description will be given of a case where fuel gas not mixed with hydrogen fuel (hereinafter, city gas of fuel type 13A will be taken as an example of fuel gas) is burned in the boiler apparatus 1.

[0042] The functional configuration of the control unit 71 for performing constant O2 control will be described. Fig. 2 is a block diagram showing the configuration of the control unit 71. As shown in Fig. 2, the control unit 71 includes a blower control unit 711, an opening setting unit 713, an oxygen concentration correction unit 714, a flow rate control unit 715, a hydrogen mixing information acquisition unit 716, and a combustion air amount correction unit 717. First, a description will be given of the blower control unit 711, the opening setting unit 713, the oxygen concentration correction unit 714, and the flow rate control unit 715. The hydrogen mixture information acquisition unit 716 and the combustion air amount correction unit 717 will be described later.

[0043] In this embodiment, the flow rate of combustion air is set according to the required load from a load device (not shown). The blower control unit 711 calculates the blower frequency based on the flow rate of combustion air set according to the required load, and controls the inverter 22 based on the blower frequency, so that the blower 20 supplies the flow rate of combustion air according to the frequency input to the inverter 22 by driving the fan at a rotational speed according to the input frequency.

[0044] The opening setting unit 713 sets an opening value indicating the opening of the flow rate adjustment valve 56 according to the required load from the load equipment (not shown). When the flow rate of combustion air is supplied by the blower control unit 711, the fuel gas flow rate is determined based on the combustion air flow rate calculated from the detection value of the air differential pressure sensor 33, and the opening value is calculated to ensure this fuel gas flow rate. A flow rate control unit 715, which will be described later, controls the flow rate adjustment valve 56 based on an opening value set to ensure a fuel gas flow rate determined based on the flow rate of combustion air supplied from the air supply line (air supply duct 30) in accordance with the required load. In this way, the flow rate control unit 715 can control the flow rate of fuel gas based on the flow rate of combustion air. This control is also referred to as "fuel gas primary adjustment." Although not shown, the functional units of the opening setting unit 713 and the flow rate control unit 715 that perform the fuel gas primary adjustment function are also referred to as "fuel gas primary adjustment function units." The memory unit 72 stores a function formula or a data table that sets an opening value corresponding to the flow rate of combustion air under predetermined conditions, and is used to calculate the opening value. The predetermined conditions here refer to various conditions that are set in advance, such as a reference calorific value based on the composition of the fuel gas, temperature (combustion air, etc.), and air ratio.

[0045] The oxygen concentration correction unit 714 corrects the opening value of the flow rate adjustment valve 56 in accordance with the oxygen concentration of the exhaust gas in order to maintain the air ratio of the boiler 2 within an appropriate range. A target oxygen concentration is set in the oxygen concentration correction unit 714. The oxygen concentration correction unit 714 corrects the opening value based on this target oxygen concentration and the oxygen concentration acquired by the O2 sensor 81. The memory unit 72 stores a function formula, a data table, or the like for correcting the opening value based on the concentration difference between this target oxygen concentration and the oxygen concentration acquired by the O2 sensor 81.

[0046] When performing the correction process, the oxygen concentration correction unit 714 reads information necessary for calculation from the storage unit 72 and corrects the aperture value. For example, if a temperature change occurs in the fuel gas and the volume of the fuel gas decreases, the mass flow rate of the fuel gas increases. Even if the volumetric flow rate of the fuel gas is constant, the oxygen concentration of the exhaust gas will be lower than the target oxygen concentration. In such a case, the aperture value is corrected to decrease the flow rate of the fuel gas. Similarly, for example, if a temperature change occurs in the fuel gas and the volume of the fuel gas increases, the mass flow rate of the fuel gas decreases. Even if the volumetric flow rate of the fuel gas is constant, the oxygen concentration of the exhaust gas will be higher than the target oxygen concentration. In such a case, the aperture value is corrected to increase the flow rate of the fuel gas. In this way, the air ratio is maintained constant by feedback-controlling the flow rate control valve 56 based on the measurement value of the O2 sensor 81 so that the oxygen concentration of the exhaust gas reaches a predetermined value (target oxygen concentration). The target oxygen concentration may be set as a concentration range with a certain width or as a single target value.

[0047] A start condition for the correction of the opening value by the oxygen concentration correction unit 714 may be set so that it starts after combustion by the burner 15 has stabilized. For example, a start condition for the correction by the oxygen concentration correction unit 714 may be that the oxygen concentration acquired by the O2 sensor 81 falls within a predetermined concentration range. Also, an expected fluctuation range of the oxygen concentration may be set, and an abnormality may be detected if the fluctuation range is exceeded. In this way, the oxygen concentration correction unit 714 corrects the opening value so that the oxygen concentration of the exhaust gas becomes a predetermined value. The flow rate control unit 715, which will be described later, controls the flow rate adjustment valve 56 based on the aperture value corrected by the oxygen concentration correction unit 714 so that the oxygen concentration of the exhaust gas becomes a predetermined value. In this way, the flow rate control unit 715 controls the aperture of the flow rate adjustment valve 56 based on the oxygen concentration of the exhaust gas. This control is also referred to as "fuel gas secondary adjustment." This allows fuel gas to be supplied to the boiler 2 at an appropriate flow rate according to the actual combustion conditions in the boiler 2. This effectively prevents a situation in which the air ratio falls outside a preset range due to the influence of fluctuations in the fuel mass flow rate or fuel components, resulting in a decrease in the combustion efficiency of the boiler 2. Although not shown, the oxygen concentration correction unit 714 and the flow rate control unit 715, which perform the fuel gas secondary adjustment function, are also referred to as "fuel gas secondary adjustment function units."

[0048] As described above, the flow rate control unit 715 controls the flow rate adjustment valve 56 based on the opening value. Specifically, in the fuel gas primary adjustment stage, the flow rate control unit 715 controls the flow rate of the fuel gas in accordance with the flow rate of combustion air supplied from the air supply line based on the load instruction, and in the fuel gas secondary adjustment stage, the flow rate control unit 715 can control the flow rate of the fuel gas so that the oxygen concentration of the exhaust gas detected by the oxygen concentration detection unit (O2 sensor 81) becomes a predetermined value. That is, after the correction process by the oxygen concentration correction unit 714 is started, the opening rate of the flow rate adjustment valve 56 is adjusted based on the opening value corrected by the oxygen concentration correction unit 714. Note that a fuel line for flow rate adjustment and a second flow rate adjustment valve (not shown) may be provided and controlled by the flow rate control unit 715. The above has described the O2 constant control function when the boiler apparatus 1 burns fuel gas not mixed with hydrogen (for example, city gas of fuel type 13A) as hydrogen fuel. Next, a case will be described in which fuel gas mixed with hydrogen as hydrogen fuel (hereinafter referred to as "hydrogen-mixed fuel gas" or simply "mixed gas") is burned by the boiler apparatus 1 having the above-mentioned O2 constant control function.

[0049] When hydrogen-mixed fuel gas is burned by the boiler apparatus 1 equipped with the above-mentioned O2 constant control function, the flow rate of the hydrogen-mixed fuel gas is set based on the air flow rate set based on the load required by the load equipment and the oxygen concentration of the exhaust gas, just as when controlling the flow rate of fuel gas that is 100% fuel type 13A. Hereinafter, fuel gas that is 100% fuel type 13A will also be referred to as "fuel gas of fuel type 13A" unless otherwise specified.

[0050] FIG. 3 is a graph showing the relationship between the hydrogen mixing ratio (the mixture ratio (vol%) of fuel gas and hydrogen gas for fuel type 13A) and the mixed gas flow rate (the ratio to the flow rate value when the hydrogen mixing ratio is 0%) under the condition that the flow rate of the combustion air and the air ratio (oxygen concentration of the exhaust gas) in the boiler apparatus 1 are constant. For example, in a boiler apparatus using a constant O2 control function, the hydrogen mixing ratio may be changed under combustion conditions where the combustion air flow rate is controlled to correspond to a desired load and the oxygen concentration of the exhaust gas is controlled to 4%. Note that in FIG. 3, the mixed gas flow rate (mixed gas amount) refers to the volumetric flow rate when the temperature and pressure are constant. 3, as the hydrogen mixing ratio increases, the flow rate of the mixed gas increases compared to the flow rate of the fuel gas of fuel type 13A. For example, when the hydrogen mixing ratio is 50%, the amount of the mixed gas is 158% of the amount of the fuel gas of fuel type 13A.

[0051] In this embodiment, as shown in FIG. 3 , the combustion air flow rate is set based on the required load, and hydrogen mixed fuel gas having a hydrogen mixing ratio of a predetermined value between 0% and 100% is burned instead of fuel gas of fuel type 13A, and the relationship between the flow rate of hydrogen mixed fuel gas and the hydrogen mixing ratio is calculated in advance based on experiments, simulations, etc., and the hydrogen mixing ratio (hereinafter referred to as a “mixed gas amount / hydrogen mixing ratio relationship table 721”) is stored in the memory unit 72. By doing so, when burning hydrogen mixed fuel gas based on a predetermined load command, the flow rate of the hydrogen mixed fuel gas is controlled, the hydrogen mixed fuel gas flow rate is measured when the oxygen concentration in the exhaust gas reaches a predetermined value (the same oxygen concentration as when burning fuel gas of fuel type 13A), and the hydrogen mixing ratio of the hydrogen mixed fuel gas can be estimated based on the measured value of the hydrogen mixed fuel gas flow rate by referring to table 721, which will be described in detail later.

[0052] On the other hand, it has been found that as the hydrogen mixing ratio increases, the thermal output when hydrogen mixed fuel gas is burned at a combustion air flow rate set based on the required load becomes higher than the thermal output when fuel gas of fuel type 13A is burned. In other words, if a set amount of combustion air is supplied based on the required load, hydrogen mixed fuel gas is burned, and the flow rate of the hydrogen mixed fuel gas is controlled so that the oxygen concentration in the exhaust gas is the same as when fuel gas of fuel type 13A is burned, the thermal load on the boiler body will increase. The higher the hydrogen mixing ratio, the greater the thermal output, which causes the boiler body to be subjected to excessive thermal load, increasing the risk of the boiler body puncturing.

[0053] FIG. 4 is a graph showing the relationship between the hydrogen mixing ratio (the mixing ratio (vol%) of fuel gas and hydrogen gas of fuel type 13A) and the amount of combustion air (the ratio relative to the flow rate value at a hydrogen mixing ratio of 0%) under conditions where the thermal output and air ratio (oxygen concentration in the exhaust gas) of the boiler apparatus 1 are constant. For example, this graph shows a case where the hydrogen mixing ratio is changed under combustion conditions where the fuel gas of fuel type 13A is controlled to produce the same thermal output as when it is combusted at a desired load and the oxygen concentration in the exhaust gas is controlled to 4%. Note that, as in FIG. 3, the amount of combustion air in FIG. 4 refers to the volumetric flow rate when the temperature and pressure are constant. As shown in FIG. 4, as the hydrogen mixing ratio increases, the ratio of the amount of combustion air required to produce the same thermal output as when combusting fuel gas of fuel type 13A to the reference air amount decreases. Here, the reference air amount refers to the amount of combustion air required to combust the same volume of fuel gas of fuel type 13A at the same air ratio (oxygen concentration in the exhaust gas). For example, when the hydrogen mixing ratio is 50%, the amount of air required for combustion is 97% of the standard amount of air. In this embodiment, the combustion air flow rate is set based on the required load, and a hydrogen-mixed fuel gas having a hydrogen mixing ratio of a predetermined value between 0% and 100% is burned instead of the fuel gas of fuel type 13A, and the relationship between the ratio of the combustion air amount to the reference air amount so that the thermal output becomes the same value as when the fuel gas of fuel type 13A is burned, and the hydrogen mixing ratio is calculated in advance based on experiments, simulations, etc., and the relationship between the combustion air flow rate and the hydrogen mixing ratio is stored in the memory unit 72 (hereinafter referred to as a ``relationship table 722 between combustion air amount and mixing ratio'').

[0054] This allows the flow rate of the mixed gas (hereinafter also referred to as "mixed gas amount") required to maintain a constant thermal output for a hydrogen mixing ratio of X% to be calculated as follows. Specifically, first, the mixed gas amount Y% when the hydrogen mixing ratio is X% is calculated based on a relationship table 721 between the mixed gas amount and the mixing ratio. Next, the ratio Z% of the air amount to the reference air amount when the hydrogen mixing ratio is X% is calculated based on a relationship table 722 between the combustion air amount and the mixing ratio. Then, when the hydrogen mixing ratio is X%, the mixed gas amount is adjusted to Y×Z / 100%, thereby maintaining a constant thermal output. For example, referring to Figure 3, if the amount of mixed gas increases to 158% compared to the amount of gas when no hydrogen is mixed, the hydrogen mixing ratio can be estimated to be 50%. On the other hand, referring to Figure 4, when the hydrogen mixing ratio is 50%, the amount of combustion air is 97% of the standard air amount when no hydrogen is mixed. Therefore, by adjusting the amount of mixed gas to 158% x (97 / 100) ≒ 153%, the rated heat quantity is achieved and the thermal output is appropriate for the required load. Note that the values ​​in Figures 3 and 4 are independent of the magnitude of the required load. Next, when changing from a 50% hydrogen mixture to a 0% hydrogen mixture, the gas volume will decrease to 97% compared to the 97% air volume. In this case, if the gas volume is returned using mixture ratio correction, it becomes 97 / 97=100%, so it can be estimated from Figure 3 that the hydrogen mixture rate is 0%. Then, the combustion air volume is corrected to 100% from Figure 4.

[0055] In this embodiment, the combustion air flow rate is set based on the required load, and a hydrogen-mixed fuel gas having a hydrogen mixing ratio of a predetermined value between 0% and 100% is burned instead of the fuel gas of fuel type 13A, and a data table or an arithmetic formula or the like that has been calculated in advance to determine the relationship between the amount of mixed gas, the ratio of fuel type 13A to the amount of fuel gas, and the hydrogen mixing ratio, such that the thermal output becomes the same value as when the fuel gas of fuel type 13A is burned, may be stored in the storage unit 72.

[0056] As described above, in this embodiment, in order to mix hydrogen gas as a hydrogen fuel into the fuel gas and burn it in the boiler device 1, the boiler device 1 needs to have the function of correcting the amount of combustion air set based on the case of fuel gas of fuel type 13A according to the hydrogen mixing ratio in the fuel gas, correcting the flow rate of the hydrogen mixed fuel gas, and controlling the thermal output to be the same as the thermal output in the case of fuel gas of fuel type 13A.

[0057] Next, a detailed configuration of the control unit 71 provided in the boiler apparatus 1 of the first embodiment for performing such control will be described. For this reason, as shown in Fig. 2, the control unit 71 of the first embodiment includes a hydrogen mixing information acquisition unit 716 and a combustion air amount correction unit 717 in addition to the configuration for performing the conventional O2 constant control described above.

[0058] The hydrogen mixture information acquisition unit 716 acquires hydrogen mixture information in the hydrogen mixture fuel gas. In a hydrogen mixing facility (not shown), for example, when hydrogen is mixed at any timing when excess hydrogen is produced (i.e., when the hydrogen mixing ratio and mixing timing are unknown), the hydrogen mixing information acquisition unit 716 can estimate the oxygen concentration in the exhaust gas based on the flow rate of the adjusted hydrogen mixed fuel gas, which has been adjusted so that the oxygen concentration in the exhaust gas becomes a predetermined value set based on the standard air volume corresponding to the required load. Specifically, for example, a combustion air amount set based on a 100% load is supplied to combust the hydrogen mixed fuel gas. If the oxygen concentration of the exhaust gas is lower than the target oxygen concentration, the oxygen concentration correction unit 714 corrects the aperture value to decrease the flow rate of the hydrogen mixed fuel gas. If the oxygen concentration of the exhaust gas is higher than the target oxygen concentration, the oxygen concentration correction unit 714 corrects the aperture value to increase the flow rate of the hydrogen mixed fuel gas. This allows the hydrogen mixing information acquisition unit 716 to calculate the hydrogen mixing ratio by referring to a relationship table 721 between the mixed gas amount and the hydrogen mixing ratio based on the flow rate of the hydrogen mixed fuel gas when the oxygen concentration of the exhaust gas converges to a predetermined value (the same oxygen concentration as when burning fuel gas of fuel type 13A). Note that, as mentioned above, when correcting the aperture value, rapid feedback control may be performed by applying, for example, the technology described in Patent Document 2. As described above, as shown in FIG. 3, at a predetermined required load, when the amount of fuel gas of fuel type 13A is 100 and the flow rate of the hydrogen mixed fuel gas converges to, for example, 158%, the hydrogen mixing information acquisition unit 716 can estimate that the hydrogen mixing ratio of the hydrogen mixed fuel gas is 50%.

[0059] In addition, if the timing for mixing hydrogen and the hydrogen mixing ratio are set in advance in the hydrogen mixing equipment (not shown), the hydrogen mixing information acquisition unit 716 may acquire the hydrogen mixing information (the timing for mixing hydrogen and the hydrogen mixing ratio) from, for example, information on the flow rate or pressure of hydrogen gas.

[0060] The combustion air amount correction unit 717 corrects the combustion air amount based on the hydrogen mixture information in the fuel gas acquired by the hydrogen mixture information acquisition unit 716. Specifically, the combustion air amount correction unit 717 calculates the ratio of the combustion air amount to the reference air amount from the combustion air amount / hydrogen mixture ratio relationship table 722 based on the required load and the hydrogen mixture information, and corrects the combustion air flow rate based on this ratio. As a result, the blower control unit 711 calculates the blower frequency based on the corrected combustion air flow rate, and controls the inverter 22 based on the blower frequency, so that the blower 20 supplies the corrected combustion air flow rate by driving the fan at a rotational speed corresponding to the frequency input to the inverter 22. Then, after the process of correcting the combustion air amount is started based on the hydrogen mixture information in the fuel gas acquired by the hydrogen mixture information acquisition unit 716, the blower frequency is calculated based on the combustion air flow rate value corrected by the combustion air amount correction unit 717, and the flow rate of combustion air is supplied at a fan rotation speed corresponding to the frequency. Specifically, for example, when the hydrogen mixture ratio is 50% as shown in FIG. 4, the combustion air amount correcting unit 717 corrects the combustion air flow rate so that the combustion air amount becomes 97% of the reference air amount. In this way, the flow rate control unit 715 controls the flow rate adjustment valve 56 based on the aperture value set by the aperture setting unit 713 so as to ensure the hydrogen mixed fuel gas flow rate (mixed gas flow rate) determined based on the corrected combustion air amount. In this way, the flow rate control unit 715 can perform "primary fuel gas adjustment" that controls the fuel gas flow rate based on the combustion air flow rate corrected based on the hydrogen mixing information. Thereafter, the oxygen concentration correction unit 714 corrects the aperture value so that the oxygen concentration of the exhaust gas acquired by the O2 sensor 81 falls within a predetermined concentration range, and the flow rate control unit 715 controls the flow rate adjustment valve 56 to adjust the mixed fuel gas flow rate (mixed gas flow rate) so that the oxygen concentration of the exhaust gas falls within the predetermined concentration range. In this way, the flow rate control unit 715 can perform "secondary fuel gas adjustment" by controlling the flow rate of the fuel gas based on the flow rate of combustion air corrected based on the hydrogen mixing information so that the oxygen concentration of the exhaust gas acquired by the O2 sensor 81 falls within the predetermined concentration range. In this way, even when a mixed gas in which hydrogen fuel is mixed with fuel gas is supplied, it can be combusted with a predetermined heat output.

[0061] The mixed gas is adjusted according to the combustion conditions of the boiler 2 and sent to the air intake duct 30 via the fuel supply line 51. The fuel gas supplied into the air intake duct 30 via the nozzle 61 is mixed with the combustion air sent into the air intake duct 30 by the blower 20. The mixed gas of the fuel gas and the combustion air is sprayed from the burner 15 into the boiler body 10 and combusted. The heat generated by the combustion of the mixed gas by the burner 15 heats the water supplied from the lower header 13 to the inside of the plurality of water pipes 12, generating steam. The steam generated in the plurality of water pipes 12 is collected in the upper header 14, and then discharged to the outside via a steam discharge pipe (not shown), and supplied to a load device (not shown). The combustion gas generated by the combustion of the mixed gas is discharged to the outside through an exhaust pipe 80.

[0062] In this way, in this embodiment, when fuel gas is mixed with hydrogen gas as hydrogen fuel to burn in the boiler device 1, even if the hydrogen gas mixing ratio fluctuates, the flow rate of the combustion air is corrected based on the hydrogen mixing information of the fuel gas, and further, the flow rate of the mixed gas supplied to the boiler 2 is appropriately adjusted based on the oxygen concentration of the exhaust gas corresponding to the load requirement (combustion rate) of the boiler 2, thereby enabling stable combustion control of the boiler 2.

[0063] The functional parts of the boiler apparatus 1 of the first embodiment have been described above. Next, a process for mixing hydrogen gas into fuel gas in the boiler apparatus 1 and burning the mixed fuel gas in the first embodiment will be described with reference to Figs. 5, 6A, and 6B. Fig. 5 is a diagram showing a process flow for burning fuel gas in the boiler apparatus 1 in accordance with a required load. Fig. 6A is a diagram showing a process flow for feedback control of the flow rate of fuel gas based on the oxygen concentration of exhaust gas. Fig. 6B is a diagram showing a process flow for calculating a corrected combustion air amount based on the hydrogen mixing ratio of the mixed fuel gas in the first embodiment in accordance with a required load.

[0064] First, with reference to FIG. 5, a process flow when the boiler apparatus 1 of the first embodiment combusts fuel gas in accordance with the required load will be described. 5 shows the processing related to the "primary fuel gas adjustment" and "secondary fuel gas adjustment" for the fuel gas (including the mixed gas) in this embodiment. For simplicity of explanation, it is assumed that at the start of the processing, the amount of combustion air is calculated based on the "fuel gas of fuel type 13A," and then the mixed gas containing hydrogen gas is supplied.

[0065] In step S10, the control unit 71 (blower control unit 711) calculates the flow rate of combustion air corresponding to the fuel gas based on the required load requested by the load equipment. As described above, at the start of the process, the flow rate of combustion air is calculated based on "fuel gas of fuel type 13A." However, if hydrogen gas is subsequently mixed into the fuel gas, the flow rate of combustion air is calculated based on the hydrogen mixing ratio of the mixed gas. The control unit 71 can determine the required combustion rate as the required load from a configuration well known to those skilled in the art, for example, from the header steam pressure value and the pressure setting value.

[0066] In step S11, the control unit 71 sets the flow rate of combustion air, calculates the blower frequency for supplying the flow rate of combustion air, and supplies the flow rate of combustion air by driving the blower 20 at a rotational speed corresponding to the frequency.

[0067] In step S12, the control unit 71 detects the flow rate of the combustion air supplied in step S11, sets the opening degree of the flow rate control valve 56 according to the detected flow rate of the combustion air, and controls the flow rate of the fuel gas (primary fuel gas adjustment).

[0068] In step S13, the control unit 71 corrects the opening value of the flow control valve 56 so that the oxygen concentration of the exhaust gas becomes a predetermined value (target concentration) or falls within the target concentration range, and performs feedback control (secondary fuel gas adjustment) of the flow rate of the fuel gas based on the corrected opening value.

[0069] The detailed processing flow of step S13 will be described. Referring to FIG. 6A, in step S131, the control unit 71 detects the oxygen concentration of the exhaust gas. In step S132, the control unit 71 detects whether the oxygen concentration of the exhaust gas is within a predetermined value (target concentration) or within a target concentration range. If the oxygen concentration of the exhaust gas is within the predetermined value (target concentration) or within the target concentration range (YES), the process proceeds to step S14. If the oxygen concentration of the exhaust gas is not within the predetermined value (target concentration) or within the target concentration range (NO), the process proceeds to step S133. In step S133, the control unit 71 controls (adjusts) the flow rate adjustment valve 56 to supply the adjusted amount of fuel gas, and then proceeds to step S131. Through the above processing, the control unit 71 can perform feedback control (secondary fuel gas adjustment) of the flow rate of the fuel gas so that the oxygen concentration of the exhaust gas becomes a predetermined value (target concentration) or falls within the target concentration range.

[0070] Returning to FIG. 5, in step S14, the control unit 71 determines whether or not the amount of combustion air needs to be corrected. Specifically, the control unit 71 determines whether or not the gas flow rate after the secondary fuel gas adjustment has increased or decreased beyond an allowable range compared to the gas flow rate before adjustment. By doing so, as described above, the control unit 71 can determine that the hydrogen mixing ratio of the fuel gas has changed. If the gas flow rate after the secondary fuel gas adjustment has increased or decreased beyond an allowable range compared to the gas flow rate before adjustment (YES), the process proceeds to step S20 shown in FIG. 6B, where the hydrogen mixing ratio is estimated and a correction value for the amount of combustion air is calculated. If the gas flow rate after the secondary fuel gas adjustment is within an allowable range compared to the gas flow rate before adjustment (NO), the process proceeds to step S15.

[0071] Here, the process for calculating the corrected combustion air amount will be described with reference to FIG. 6B. Referring to FIG. 6B, in step S20, the control unit 71 calculates the degree to which the amount of mixed gas has increased compared to the amount of gas when hydrogen is not mixed, based on the flow rate of the fuel gas after feedback control (secondary fuel gas adjustment), and estimates the hydrogen mixing ratio by, for example, referring to a "relationship table 721 between mixed gas amount and hydrogen mixing ratio." In step S21, the control unit 71 refers to, for example, the "relationship table 722 between combustion air amount and mixing ratio" to calculate the ratio of the combustion air amount to the reference air amount at the hydrogen mixing ratio that results in an appropriate thermal output according to the required load, and calculates the corrected combustion air amount.

[0072] 5, the process then proceeds to step S11. In this way, the control unit 71 sets a corrected combustion air amount suitable for the fuel gas, calculates a blower frequency for supplying the flow rate of the corrected combustion air, and drives the blower 20 at a rotation speed according to the frequency, thereby supplying the flow rate of the corrected combustion air.

[0073] 5, in step S15, the control unit 71 returns to step S12 and executes the process unless the required load is changed, in which case the process proceeds to step S10. As described above, in step S10, the control unit 71 (blower control unit 711) calculates the flow rate of combustion air according to the current hydrogen mixture ratio of the fuel gas based on the load required by the load device.

[0074] Through the above processing, even if the hydrogen proportion of the mixed gas fluctuates according to the load requirement (combustion rate), the control unit 71 can burn at a predetermined thermal output even if the mixture ratio of hydrogen fuel to other gas fuel in the mixed gas fuel changes by supplying a corrected amount of combustion air based on the hydrogen mixture ratio in addition to the primary fuel gas adjustment and secondary fuel gas adjustment.

[0075] The boiler apparatus 1 of the first embodiment described above provides the following effects.

[0076] The boiler apparatus 1 of the first embodiment includes a hydrogen mixture information acquisition unit 716 that acquires hydrogen mixture information in a fuel gas mixed with hydrogen gas as a hydrogen fuel, and a combustion air amount correction unit 717 that corrects the combustion air amount based on the hydrogen mixture information in the hydrogen-mixed fuel gas acquired by the hydrogen mixture information acquisition unit 716.

[0077] As a result, when the boiler device 1 is burned by mixing hydrogen gas as hydrogen fuel into the fuel gas, the boiler device 1 can be stably controlled in response to load requirements even when hydrogen gas is mixed as hydrogen fuel. Specifically, for example, when hydrogen gas as a hydrogen fuel is mixed with a fuel gas such as city gas, the amount of fuel gas supplied, calculated based on the amount of combustion air in the case of 100% city gas, may become excessive, resulting in the specified thermal output being exceeded. However, by making the above correction, the specified thermal output can be stably controlled without exceeding the specified thermal output.

[0078] a fuel gas flow rate detection unit (60) for detecting the flow rate of fuel gas flowing through the fuel supply line; The hydrogen mixing information acquisition unit 716 can estimate the oxygen concentration in the exhaust gas based on the flow rate of the adjusted fuel gas detected by the fuel gas flow rate detection unit 60, which has been adjusted so that the oxygen concentration in the exhaust gas becomes a predetermined value set based on the amount of combustion air.

[0079] This makes it possible to estimate information about the amount of hydrogen mixed in the fuel gas based on the oxygen concentration in the exhaust gas and the corrected amount of fuel gas.

[0080] Although each preferred embodiment of the boiler apparatus 1 of the present invention has been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate. In this embodiment, hydrogen gas has been described as an example of the hydrogen fuel, but it is not limited to hydrogen gas. For example, in addition to hydrogen gas, ammonia gas and a mixed gas of hydrogen, nitrogen, and ammonia obtained by decomposing ammonia may also be used. In this case, the present invention can be implemented by replacing the description of "hydrogen gas" in this embodiment with "hydrogen fuel."

[0081] In the above embodiment, in a case where hydrogen is mixed in a hydrogen mixing facility (not shown), for example, at an arbitrary timing when excess hydrogen is produced (i.e., when the hydrogen mixing ratio and mixing timing are unknown), the hydrogen mixing information acquisition unit 716 is configured to estimate the hydrogen mixing ratio based on the flow rate of the adjusted hydrogen mixed fuel gas, which has been adjusted so that the oxygen concentration in the exhaust gas becomes a predetermined value set based on the reference air amount corresponding to the required load.

[0082] A brief description will be given of the case where the hydrogen mixing ratio is further changed in the hydrogen mixing equipment (not shown) in the above embodiment. In this case, as in the graph shown in Figure 3, the amount of mixed gas when a hydrogen-mixed fuel gas with a hydrogen mixing ratio of a predetermined value between 0% and 100% is burned to output the rated heat amount is set to 100%, and when the amount of mixed gas is fed back so that the oxygen concentration in the exhaust gas becomes the target oxygen concentration, for example, if the hydrogen mixing ratio becomes small, the amount of mixed gas is corrected to decrease, and if the hydrogen mixing ratio becomes large, the amount of mixed gas is corrected to increase. In this way, the flow rate of the hydrogen-mixed fuel gas when the oxygen concentration of the exhaust gas becomes the target oxygen concentration may be measured, and the hydrogen mixture ratio of the changed hydrogen-mixed fuel gas may be estimated based on the measured flow rate of the hydrogen-mixed fuel gas. In this way, the air amount may be corrected based on the hydrogen mixture ratio, and the flow rate of the hydrogen-mixed fuel gas may be corrected.

[0083] In these embodiments, if the timing for mixing hydrogen and the hydrogen mixing ratio are set in advance in the hydrogen mixing equipment (not shown), the hydrogen mixing information acquisition unit 716 may acquire the hydrogen mixing information (the timing for mixing hydrogen and the hydrogen mixing ratio) from the hydrogen mixing equipment (not shown), and the control unit 7 (hydrogen mixing information acquisition unit 716) may acquire the hydrogen mixing information (the timing for mixing hydrogen and the hydrogen mixing ratio) from the hydrogen mixing equipment (not shown) via an external interface (not shown).

[0084] In this case, the control unit 7 (combustion air amount correction unit 717) can supply a flow rate of combustion air according to the required load by correcting the combustion air amount based on the hydrogen mixture information in the fuel gas acquired by the hydrogen mixture information acquisition unit 716. In this way, as described above, even if the mixture ratio of hydrogen fuel and other gas fuel in the gas fuel changes, combustion can be performed with a predetermined heat output. [Explanation of symbols]

[0085] 1. Boiler equipment 2 boilers 20 Blower 21 Blower body 22 Inverter 30 Air intake duct (air supply line) 33 Air differential pressure sensor (air flow detection part) 51 Fuel supply line 56 Flow control valve 60 Fuel gas differential pressure sensor (fuel gas flow rate detection section) 70 Control device 71 Control Unit 711 Blower control unit 713 Opening setting unit 714 Oxygen concentration correction unit 715 Flow Control Unit 716 Hydrogen Mixture Information Acquisition Unit 717 Combustion air volume correction unit 72 Memory section 721 Relationship table between mixed gas amount and hydrogen mixture ratio 722 Relationship table between combustion air volume and hydrogen mixture ratio 80 Exhaust stack (exhaust gas exhaust section) 81 O2 sensor (oxygen concentration detection part)

Claims

1. Boiler and a fuel supply line for supplying fuel gas mixed with hydrogen fuel to the boiler; a flow rate adjusting valve disposed in the fuel supply line and capable of adjusting a flow rate of the fuel gas; an air supply line for supplying combustion air to the boiler; an air flow rate detection unit that detects the flow rate of the combustion air flowing through the air supply line; an exhaust gas discharge section that discharges exhaust gas generated by combustion of the fuel gas from the boiler; an oxygen concentration detection unit disposed in the exhaust gas discharge unit and configured to detect an oxygen concentration of the exhaust gas; a control unit for controlling the amounts of fuel gas and combustion air supplied to the boiler; Equipped with The control unit a fuel gas primary regulation function unit that controls the flow rate of the fuel gas in accordance with the flow rate of combustion air supplied from the air supply line based on a load instruction; a fuel gas secondary regulation function unit that controls the flow rate regulation valve so that the oxygen concentration of the exhaust gas detected by the oxygen concentration detection unit becomes a predetermined value; a hydrogen mixture information acquisition unit that acquires hydrogen mixture information of the fuel gas; a combustion air amount correction unit that corrects the flow rate of the combustion air based on the hydrogen mixture information of the fuel gas acquired by the hydrogen mixture information acquisition unit; A boiler apparatus comprising:

2. a fuel gas flow rate detection unit that detects the flow rate of the fuel gas flowing through the fuel supply line, The hydrogen mixing information acquisition unit 2. The boiler apparatus according to claim 1, wherein the hydrogen mixing information is estimated based on the flow rate of the fuel gas detected by the fuel gas flow rate detection unit after the fuel gas has been adjusted so that the oxygen concentration of the exhaust gas is a predetermined value that is set based on the flow rate of the combustion air.

3. The hydrogen mixing information acquisition unit The boiler apparatus according to claim 1, wherein hydrogen mixture information is calculated based on the amount of hydrogen fuel input to the fuel gas.

4. The hydrogen mixing information acquisition unit The boiler apparatus according to claim 1 , wherein the hydrogen mixture information is acquired by receiving a signal related to the hydrogen mixture information.

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