Control device, control method, control program, and combustion device

Abstract

To provide a control device that contributes to improvement of combustion efficiency of a combustion apparatus.SOLUTION: A control device (14) in one aspect is used in a combustion apparatus (1) that burns an air-fuel mixture of gas fuel that does not include carbon and air and for controlling supply amount of gas fuel or air. The control device corrects an air ratio calculated through feed forward control so that an air ratio in a preset condition follows a change of a temperature of air to be supplied to the combustion apparatus (1) by using a correction value calculated through feedback control so that a concentration of unburned gas fuel obtained from exhaust gas after combustion of the air-fuel mixture becomes a preset reference value, and controls the supply amount of the gas fuel or air on the basis of a corrected air ratio obtained by correcting the calculated air ratio by using the correction value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device, a control method, a control program, and a combustion device, and more particularly to a control device, a control method, a control program, and a combustion device for controlling the supply amount of gaseous fuel or air, for example, used in a combustion device that burns a mixture of carbon-free gaseous fuel and air. [Background technology]

[0002] In recent years, there has been a demand for more efficient fuel combustion in combustion devices such as plants from the viewpoint of ecology, etc. For example, Patent Document 1 discloses a technology for calculating the hydrogen concentration during combustion and adjusting the supply amounts of hydrogen and air based on the calculated hydrogen concentration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-184896 Summary of the Invention [Problem to be solved by the invention]

[0004] The applicant has discovered the following problem: The amount of oxygen contained in the air used as fuel varies depending on the air temperature, so there is a limit to how much combustion efficiency can be improved even if the supply amounts of hydrogen and air are adjusted based solely on the hydrogen concentration during combustion, as in the technology of Patent Document 1.

[0005] The present disclosure has been made in consideration of such problems, and provides a control device, a control method, a control program, and a combustion device that contribute to improving the combustion efficiency of a combustion device. [Means for solving the problem]

[0006] A control device according to one aspect of the present disclosure is a control device used in a combustion device that combusts a mixture of carbon-free gaseous fuel and air, for controlling a supply amount of the gaseous fuel or the air, the control device comprising: A first air ratio calculated by feedforward control so that the air ratio under preset conditions follows changes in the temperature of the air supplied to the combustion device is corrected with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust after combustion of the mixture becomes a preset reference value, and the supply amount of the gaseous fuel or the air is controlled based on the corrected air ratio obtained by correcting the first air ratio with the correction value.

[0007] When the concentration of nitrogen oxides obtained from the exhaust gas after combustion of the mixture is equal to or higher than a predetermined first threshold, the above-mentioned control device preferably controls the supply amount of the gaseous fuel or the air based on a second air ratio that is calculated in advance and that makes the concentration of nitrogen oxides less than the first threshold, in preference to the corrected air ratio.

[0008] When the temperature of the housing to which the gaseous fuel and the air in the combustion device are supplied, obtained during combustion of the mixture, is equal to or higher than a predetermined second threshold, the above-mentioned control device preferably controls the supply amount of the gaseous fuel or the air based on a third air ratio that prioritizes the corrected air ratio and makes the previously calculated temperature of the housing less than the second threshold.

[0009] In the above-described control device, it is preferable that the first air ratio is calculated by feedforward control so that the air ratio under the preset conditions follows changes in the temperature and pressure of the air supplied to the combustion device.

[0010] In the above-described control device, it is preferable that the predetermined reference value is a concentration of the unburned gaseous fuel in the exhaust gas after combustion of the air-fuel mixture of 0%.

[0011] A combustion device according to one aspect of the present disclosure includes: a first supply line for supplying the air; a first valve provided in the first supply line for adjusting the amount of air supplied; a second supply line for supplying the gaseous fuel; a second valve provided in the second supply line to adjust the supply amount of the gaseous fuel; a first detector for detecting the temperature of the air; a second detection unit that detects the concentration of the unburned gaseous fuel; The above-mentioned control device that controls the first valve or the second valve; a burner connected to the first supply line and the second supply line; a housing provided on the burner; Equipped with.

[0012] A control method according to one aspect of the present disclosure is used in a combustion device that combusts a mixture of carbon-free gaseous fuel and air, and is for controlling a supply amount of the gaseous fuel or the air, the control method comprising: The air ratio calculated by feedforward control so that the air ratio under preset conditions follows changes in the temperature of the air supplied to the combustion device is corrected with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust after combustion of the mixture becomes a preset reference value, and the supply amount of the gaseous fuel or the air is controlled based on the corrected air ratio obtained by correcting the calculated air ratio with the correction value.

[0013] A control program according to one aspect of the present disclosure is used in a combustion device that combusts a mixture of carbon-free gaseous fuel and air, and is for controlling a supply amount of the gaseous fuel or the air, The computer executes a process of correcting the air ratio calculated by feedforward control so that the air ratio under preset conditions follows changes in the temperature of the air supplied to the combustion device with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust after combustion of the mixture becomes a preset reference value, and controlling the supply amount of the gaseous fuel or the air based on the corrected air ratio obtained by correcting the calculated air ratio with the correction value. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to realize a control device, a control method, a control program, and a combustion device that contribute to improving the combustion efficiency of the combustion device. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram schematically illustrating a combustion device according to an embodiment; [Figure 2] 2 is a block diagram showing the configuration of a control system of the combustion apparatus according to the embodiment; FIG. [Figure 3] 1 is a block diagram showing a configuration of a control device according to an embodiment; [Figure 4] FIG. 4 is a flowchart showing a flow of controlling the amount of air supplied in the combustion device according to the embodiment. [Figure 5] FIG. 4 is a diagram showing the relationship between time and the amount of combustion air in the combustion device of the embodiment. [Figure 6] FIG. 2 is a diagram illustrating an example of a hardware configuration included in a control device. DETAILED DESCRIPTION OF THE INVENTION

[0016] Specific embodiments to which the present disclosure is applied will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings have been simplified as appropriate for clarity of explanation.

[0017] First, the configuration of the combustion device of this embodiment will be described. Fig. 1 is a diagram that schematically shows the combustion device of this embodiment. Fig. 2 is a block diagram that shows the configuration of a control system of the combustion device of this embodiment. The combustion device 1 of this embodiment burns a mixture of air and a gaseous fuel that does not contain carbon, such as hydrogen or ammonia.

[0018] As shown in Figures 1 and 2, the combustion device 1 includes a housing 2, a burner 3, a first supply line 4, a fan 5, a first valve 6, a second supply line 7, a second valve 8, a first detection unit 9, a second detection unit 10, a third detection unit 11, a fourth detection unit 12, a fifth detection unit 13, and a control device 14.

[0019] The housing 2 is a combustion chamber that burns a mixture of supplied gaseous fuel and air, and as shown in Fig. 1, a chimney 2a is connected to the housing 2. The burner 3 is provided in the housing 2 and is a combustion device that burns the mixture of supplied gaseous fuel and air. The first supply line 4 is a supply pipe for supplying air to the burner 3, and one end of the first supply line 4 is connected to the burner 3.

[0020] 1, the fan 5 is connected to the other end of the first supply line 4 and takes in air from the atmosphere and supplies it to the first supply line 4. However, it does not have to be a fan and may be, for example, a pump, as long as it is configured to supply air to the first supply line 4. The first valve 6 is provided on the first supply line 4 and is driven by a drive source (not shown) to adjust the amount of air supplied to the burner 3.

[0021] The second supply line 7 is a supply pipe for supplying gaseous fuel to the burner 3, and as shown in Fig. 1, one end of the second supply line 7 is connected to the burner 3. The other end of the second supply line 7 is connected to, for example, a tank (not shown) that stores the gaseous fuel. The second valve 8 is provided on the second supply line 7, and is driven by a drive source (not shown) to adjust the amount of gaseous fuel supplied to the burner 3.

[0022] The first detection unit 9 is equipped with a temperature measuring device that detects the temperature of the air, and outputs the detected air temperature data to the control device 14. The first detection unit 9 is disposed in the atmosphere (i.e., outside the combustion device 1) so that it can detect the temperature of the air taken in by the fan 5, for example. However, it is sufficient that the first detection unit 9 is disposed so that it can detect the temperature of the air before it is supplied to the burner 3.

[0023] The second detection unit 10 is equipped with a pressure measuring instrument that detects the pressure of the air, and outputs the detected air pressure data to the control device 14. The second detection unit 10 is disposed in the atmosphere, for example, so that it can detect the pressure of the air taken in by the fan 5. However, it is sufficient that the second detection unit 10 is disposed so that it can detect the pressure of the air before the air is supplied to the burner 3.

[0024] The third detection unit 11 includes a concentration meter (e.g., a combustible gas detector) that detects the concentration of unburned gaseous fuel in the exhaust gas after the air-fuel mixture is combusted, and outputs the detected unburned gaseous fuel concentration data to the control device 14. The third detection unit 11 is fixed, for example, inside the chimney 2a connected to the housing 2 so that it can detect the concentration of unburned gaseous fuel in the exhaust gas. However, it is sufficient that the third detection unit 11 is disposed so that it can detect the concentration of unburned gaseous fuel in the exhaust gas after the air-fuel mixture is combusted.

[0025] The fourth detection unit 12 is equipped with a concentration meter that detects the concentration of nitrogen oxides (NOx) in the exhaust gas after the air-fuel mixture is combusted, and outputs the detected nitrogen oxide concentration data to the control device 14. The fourth detection unit 12 is fixed, for example, inside the chimney 2a connected to the housing 2 so that it can detect the concentration of nitrogen oxides in the exhaust gas. However, it is sufficient that the fourth detection unit 12 is positioned so that it can detect the concentration of nitrogen oxides in the exhaust gas after the air-fuel mixture is combusted.

[0026] The fifth detection unit 13 is equipped with a temperature measuring device that detects the temperature of the housing 2 during combustion of the air-fuel mixture, and outputs the detected temperature data of the housing 2 to the control device 14. The fifth detection unit 13 is fixed to the housing 2. It is preferable that the fifth detection unit 13 is disposed, for example, near a location of the housing 2 where the temperature is highest during combustion of the air-fuel mixture.

[0027] The control device 14 controls the first valve 6 or the second valve 8 to control the supply amount of gaseous fuel or air based on the air temperature data, air pressure data, and unburned gaseous fuel concentration data so that the unburned gaseous fuel concentration approaches a preset reference value.

[0028] At this time, the control device 14 prioritizes control of the amount of gaseous fuel or air supplied based on nitrogen oxide concentration data over control of the amount of gaseous fuel or air supplied based on air temperature data, air pressure data, and unburned gaseous fuel concentration data, and further prioritizes control of the amount of gaseous fuel or air supplied based on temperature data of the housing 2 over these.

[0029] Next, a block diagram showing the configuration of the control device 14 of this embodiment is shown in Fig. 3. The control device 14 includes a corrected air ratio calculation unit 20, a second air ratio calculation unit 30, a first selection unit 40, a third air ratio calculation unit 50, a second selection unit 60, a supply amount calculation unit 70, and a control unit 80, as shown in Fig. 3.

[0030] 3, the corrected air ratio calculation unit 20 includes a feedforward control unit (FF control unit) 21, a feedback control unit (FB control unit) 22, a selection unit 23, and a comparator 24. The feedforward control unit 21 calculates the first air ratio so that the air ratio under preset conditions follows changes in the air temperature detected by the first detection unit 9 and the air pressure detected by the second detection unit 10.

[0031] For example, the preset conditions are an air temperature of 0°C and an air pressure of atmospheric pressure (101.3 Pa), and the air ratio under these conditions is 1. For example, if the air temperature detected by the first detection unit 9 is -10°C and the air pressure detected by the second detection unit 10 is 103 Pa, the first air ratio can be calculated as follows:

[0032] Generally, based on the equation of state for an ideal gas, (101.3 × V0) / (R × 273.15) = (103 × V) / (R × 263.15) holds, so the first air ratio is V / V0 = 101.3 / 103 × 263.15 / 273.15 = 0.947.

[0033] Here, R is the gas constant, V is the volume of air when the air temperature is -10°C and the air pressure is 103 Pa, and V0 is the volume of air when the air temperature is 0°C and the air pressure is 101.3 Pa.

[0034] In this way, the feedforward control unit 21 can calculate the first air ratio based on the equation of state of an ideal gas, the air ratio under preset conditions, the air temperature detected by the first detection unit 9, and the air pressure detected by the second detection unit 10.

[0035] The feedback control unit 22 calculates a correction value by feedback control so that the concentration of unburned gaseous fuel detected by the third detection unit 11 becomes a preset reference value. In other words, as will be described later, the feedback control unit 22 calculates a correction value so that the concentration of unburned gaseous fuel detected by the third detection unit 11 becomes a preset reference value when burning an air-fuel mixture in which the supply amount of gaseous fuel or air is adjusted based on a corrected air ratio in which the first air ratio is corrected by the previously calculated correction value. Here, the preset reference value may be such that the concentration of unburned gaseous fuel in the exhaust gas after combustion of the air-fuel mixture is 0%.

[0036] If the correction value calculated by the feedback control unit 22 is less than 0, the selection unit 23 selects 0 as the correction value, and if the correction value calculated by the feedback control unit 22 is 0 or greater, the selection unit 23 selects the correction value calculated by the feedback control unit 22.

[0037] In other words, if the correction value calculated by the feedback control unit 22 is less than 0, for example, there is a high possibility that an error has occurred in the unburned gas fuel concentration data detected by the third detection unit 11, and therefore the selection unit 23 selects 0 as the correction value.

[0038] The comparator 24 adds the first air ratio calculated by the feedforward control unit 21 and the correction value selected by the selection unit 23 to calculate a corrected air ratio in which the first air ratio is corrected by the correction value.

[0039] 3, the second air ratio calculation unit 30 includes a feedback control unit (FB control unit) 31. The feedback control unit 31 calculates the second air ratio at which the concentration of nitrogen oxides detected by the fourth detection unit 12 is less than the first threshold value. Here, the first threshold value may be set to a value that has a margin with respect to, for example, environmental standards.

[0040] For example, if the amount of air supplied is large, the amount of oxygen that combines with nitrogen increases, and the concentration of nitrogen oxides rises. Therefore, the feedback control unit 31 decreases the second air ratio, for example, by reducing the amount of air supplied so that the concentration of nitrogen oxides becomes less than the first threshold. However, if the concentration of nitrogen oxides can be reduced, the second air ratio may be increased.

[0041] The first selection unit 40 selects the second air ratio calculated by the second air ratio calculation unit 30 when the concentration of nitrogen oxides detected by the fourth detection unit 12 is equal to or higher than the first threshold, and selects the corrected air ratio calculated by the corrected air ratio calculation unit 20 when the concentration of nitrogen oxides detected by the fourth detection unit 12 is lower than the first threshold. This makes it possible to combust the air-fuel mixture by prioritizing environmental standards, which should be prioritized over combustion efficiency.

[0042] 3, the third air ratio calculation unit 50 includes a feedback control unit (FB control unit) 51. The feedback control unit 51 calculates the third air ratio at which the temperature of the housing 2 detected by the fifth detection unit 13 is less than the second threshold value. Here, the second threshold value may be set to a value that has a margin relative to the temperature at which the housing 2 is damaged, for example.

[0043] For example, when the amount of air supplied is small, the combustion temperature rises, causing a rise in the temperature of the housing 2. Therefore, the feedback control unit 51 increases the third air ratio, for example, by increasing the amount of air supplied so that the temperature of the housing 2 becomes less than the second threshold value.

[0044] If the temperature of the housing 2 detected by the fifth detection unit 13 is equal to or higher than the second threshold, the second selection unit 60 selects the third air ratio calculated by the third air ratio calculation unit 50, and if the temperature of the housing 2 detected by the fifth detection unit 13 is lower than the second threshold, the second selection unit 60 selects the corrected air ratio or the second air ratio selected by the first selection unit 40. This makes it possible to combust the air-fuel mixture while prioritizing the safety of the combustion device 1, which is the highest priority.

[0045] The supply amount calculation unit 70 calculates the amount of air or gaseous fuel to be supplied to the burner 3 based on the air ratio (i.e., the corrected air ratio, the second air ratio, or the third air ratio) selected by the second selection unit 60. The supply amount calculation unit 70 calculates, for example, the amount of air to be supplied, i.e., the amount of air required to combust the gaseous fuel to be supplied.

[0046] In detail, for example, when the gaseous fuel is hydrogen, hydrogen 1 (Nm 3 ) requires 0.5 (Nm 3 ) and the oxygen concentration in the air is 21%, so the theoretical air volume is 0.5 × 100 / 21 = 2.38 (Nm 3 (Air) / Nm 3 (H2)).

[0047] In this case, if the air ratio is 0.947 as mentioned above, 2.38 × 0.947 = 2.25 (Nm3 (Air) / Nm 3 (H2)). And the hydrogen supply is 20 (Nm 3 (H2) / h), the air supply is 2.25 (Nm 3 (Air) / Nm 3 (H2)) x 20 (Nm 3 (H2) / h)=45(Nm 3 (Air) / h).

[0048] In this way, the supply amount calculation unit 70 can calculate the amount of air supplied. However, although the supply amount calculation unit 70 calculates the amount of air supplied, if the control device 14 adjusts the amount of gaseous fuel such as hydrogen supplied, the supply amount calculation unit 70 may calculate the amount of gaseous fuel supplied.

[0049] The control unit 80 controls the first valve 6 or the second valve 8 based on the amount of air supply or the amount of gaseous fuel supply calculated by the supply amount calculation unit 70. In detail, the control unit 80 calculates the degree of opening of the first valve 6 based on, for example, a characteristic curve showing the relationship between the flow rate and valve opening of the first valve 6 and the amount of air supply calculated by the supply amount calculation unit 70, and generates a control signal for realizing the calculated degree of opening. Then, the control unit 80 controls the first valve 6 based on the generated control signal.

[0050] However, the control unit 80 may calculate the opening degree of the second valve 8 based on a characteristic curve showing the relationship between the flow rate and valve opening degree of the second valve 8 and the supply amount of gaseous fuel calculated by the supply amount calculation unit 70, and control the second valve 8 based on a control signal generated to realize the calculated opening degree.

[0051] Next, a flow of controlling the amount of air supplied in the combustion apparatus 1 of this embodiment will be described. Fig. 4 is a flowchart showing a flow of controlling the amount of air supplied in the combustion apparatus of this embodiment. Here, the following description is based on the premise that a mixture of gaseous fuel and air is already being burned in the combustion apparatus 1. Also, the amount of air supplied is adjusted based on the selected air ratio.

[0052] First, the corrected air ratio calculation unit 20 calculates the corrected air ratio (S1). In detail, the feedforward control unit 21 of the corrected air ratio calculation unit 20 acquires air temperature data from the first detection unit 9 and air pressure data from the second detection unit 10, and calculates the first air ratio by feedforward control so that the air ratio under preset conditions follows changes in the air temperature detected by the first detection unit 9 and the air pressure detected by the second detection unit 10.

[0053] At the same time, the feedback control unit 22 of the corrected air ratio calculation unit 20 acquires unburned gaseous fuel concentration data from the third detection unit 11, and calculates a correction value by feedback control so that the unburned gaseous fuel concentration detected by the third detection unit 11 becomes a preset reference value.

[0054] Next, the selection unit 23 of the corrected air ratio calculation unit 20 selects 0 as the correction value if the correction value calculated by the feedback control unit 22 is less than 0, and selects the correction value calculated by the feedback control unit 22 if the correction value calculated by the feedback control unit 22 is 0 or more.

[0055] Next, the comparator 24 of the corrected air ratio calculation unit 20 adds the first air ratio calculated by the feedforward control unit 21 and the correction value selected by the selection unit 23 to calculate a corrected air ratio in which the first air ratio is corrected by the correction value.

[0056] Next, the first selection unit 40 determines whether the concentration of nitrogen oxides detected by the fourth detection unit 12 is equal to or greater than a first threshold, and if the concentration of nitrogen oxides is equal to or greater than the first threshold, selects the second air ratio calculated by the second air ratio calculation unit 30, and if the concentration of nitrogen oxides is less than the first threshold, selects the corrected air ratio calculated by the corrected air ratio calculation unit 20 (S2).

[0057] At this time, the feedback control unit 31 of the second air ratio calculation unit 30 may acquire nitrogen oxide concentration data from the fourth detection unit 12 constantly or intermittently while the combustion device 1 is burning the air-fuel mixture, and calculate a second air ratio at which the nitrogen oxide concentration detected by the fourth detection unit 12 is less than the first threshold value.

[0058] Next, the second selection unit 60 determines whether the temperature of the housing 2 detected by the fifth detection unit 13 is equal to or higher than the second threshold, and if the temperature of the housing 2 is equal to or higher than the second threshold, selects the third air ratio calculated by the third air ratio calculation unit 50, and if the temperature of the housing 2 is lower than the second threshold, selects the corrected air ratio selected by the first selection unit 40 or the second air ratio (S3).

[0059] At this time, the feedback control unit 51 of the third air ratio calculation unit 50 acquires temperature data of the housing 2 from the fifth detection unit 13 constantly or intermittently while the combustion device 1 is burning the mixture, and calculates the third air ratio at which the temperature of the housing 2 detected by the fifth detection unit 13 is less than the second threshold value.

[0060] Next, the supply amount calculation unit 70 calculates the amount of air to be supplied to the burner 3 based on the air ratio selected by the second selection unit 60 (S4). Then, the control unit 80 controls the first valve based on the amount of air to be supplied calculated by the supply amount calculation unit 70 (S5).

[0061] In this way, the combustion device 1, control device 14, and control method of this embodiment correct the first air ratio calculated by feedforward control so that the air ratio under preset conditions follows changes in the temperature and pressure of the air supplied to the combustion device 1 with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel in the exhaust after combustion of the mixture becomes a preset reference value, and control the supply amount of gaseous fuel or air based on the corrected air ratio obtained by correcting the first air ratio with the correction value.

[0062] Here, Fig. 5 is a diagram showing the relationship between time and the amount of combustion air in the combustion device of this embodiment. That is, when controlling the amount of air supplied, for example, the combustion device 1, control device 14, and control method of this embodiment correct the theoretical air amount under preset conditions by feedforward control (FF control) based on the temperature and pressure of the air supplied to the combustion device 1, as shown in Fig. 5, and further control the amount of air supplied by feedback control (FB control) so that the unburned gaseous fuel concentration approaches an optimal air amount that is a preset reference value.

[0063] This allows the amount of air or gaseous fuel supplied to be adjusted based on disturbances such as changes in air temperature and pressure, compared to when the amount of air or gaseous fuel supplied is controlled based only on the concentration of unburned gaseous fuel, thereby contributing to improving the combustion efficiency of the combustion device 1. In particular, the feedforward control allows the amount of air or gaseous fuel supplied to be controlled with good response to the influence of disturbances such as changes in air temperature and pressure.

[0064] Moreover, the gaseous fuel used in the combustion device 1, control device 14, and control method of this embodiment does not contain carbon, so even if it is incompletely burned, there is little harm, and the air ratio can be made as close to 1 as possible to improve combustion efficiency. In this case, if the concentration of unburned gaseous fuel is set to 0% as a preset reference value, the combustion efficiency can be further improved.

[0065] Furthermore, the combustion device 1, control device 14, and control method of this embodiment select the second air ratio calculated by the second air ratio calculation unit 30 when the concentration of nitrogen oxides detected by the fourth detection unit 12 is equal to or higher than the first threshold, and select the corrected air ratio calculated by the corrected air ratio calculation unit 20 when the concentration of nitrogen oxides is less than the first threshold. This makes it possible to combust the air-fuel mixture by prioritizing environmental standards, which should be prioritized over combustion efficiency.

[0066] Furthermore, the combustion device 1, control device 14, and control method of this embodiment select the third air ratio calculated by the third air ratio calculation unit 50 when the temperature of the housing 2 detected by the fifth detection unit 13 is equal to or higher than the second threshold, and select the corrected air ratio or the second air ratio selected by the first selection unit 40 when the temperature of the housing 2 is lower than the second threshold. This makes it possible to combust the air-fuel mixture while prioritizing the safety of the combustion device 1, which is the highest priority.

[0067] Although the present disclosure has been described as a hardware configuration in the first embodiment, the present disclosure is not limited to this. The present disclosure can also be realized by having a CPU (Central Processing Unit) execute a computer program to perform the processing of each component.

[0068] For example, the control device 14 of the above embodiment may have the following hardware configuration: Fig. 6 is a diagram showing an example of the hardware configuration included in the control device.

[0069] 6 includes an interface 91, a processor 92, and a memory 93. The control device 14 described in the above embodiment is realized by the processor 92 reading and executing a program stored in the memory 93. In other words, this program causes the processor 92 to function as the control device 14.

[0070] Here, a program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0071] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure.

[0072] For example, in the above embodiment, the second air ratio calculation unit 30, the first selection unit 40, the third air ratio calculation unit 50, and the second selection unit 60 are provided, but these may be omitted. Also, either the second air ratio calculation unit 30 and the first selection unit 40, or the third air ratio calculation unit 50 and the second selection unit 60 may be provided.

[0073] For example, the second air ratio calculation unit 30 and the third air ratio calculation unit 50 in the above embodiment calculate the air ratio by feedback control, but the calculation method is not limited as long as it is possible to calculate an air ratio that is equal to or less than a preset threshold value.

[0074] For example, in the above embodiment, when calculating the first air ratio, the air ratio under preset conditions is made to follow changes in air temperature and pressure, but it is sufficient if the air ratio under preset conditions is made to follow at least changes in air temperature.

[0075] For example, in the above embodiment, the amount of air supplied or the amount of gaseous fuel supplied is adjusted, but it is also possible to adjust both the amount of air supplied and the amount of gaseous fuel supplied. [Explanation of symbols]

[0076] 1 Combustion equipment 2 enclosure, 2a chimney 3 burners 4. First Supply Line 5 Fans 6 First Valve 7 Second Supply Line 8 Second Valve 9 First detection unit 10 Second detection unit 11 Third detection unit 12 Fourth detection unit 13 Fifth detector 14 Control device 20 Corrected air ratio calculation section 21 Feedforward control section 22 Feedback control section 23 Selection section 24 Comparator 30 Second air ratio calculation unit 31 Feedback control section 40 First selection section 50 Third air ratio calculation unit 51 Feedback control section 60 Second Selection Section 70 Supply amount calculation section 80 Control Unit 91 Interface 92 processors 93 memory

Claims

1. 1. A control device for controlling a supply amount of a gaseous fuel or air used in a combustion device that burns a mixture of a carbon-free gaseous fuel and air, comprising: a first air ratio calculated by feedforward control so that the air ratio under preset conditions follows a change in the temperature of the air supplied to the combustion device, the first air ratio being calculated by a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust gas after combustion of the air-fuel mixture becomes a preset reference value; and the supply amount of the gaseous fuel or the air is controlled based on a corrected air ratio obtained by correcting the first air ratio by the correction value; When the concentration of nitrogen oxides obtained from the exhaust gas after combustion of the mixture is equal to or higher than a predetermined first threshold, the control device controls the supply amount of the gaseous fuel or the air based on a second air ratio that is calculated in advance and that makes the concentration of nitrogen oxides less than the first threshold, in preference to the corrected air ratio.

2. 2. The control device according to claim 1, wherein, when the temperature of a housing to which the gaseous fuel and the air in the combustion device are supplied, obtained during combustion of the mixture, is equal to or higher than a predetermined second threshold, the control device controls the supply amount of the gaseous fuel or the air based on a third air ratio that makes the previously calculated temperature of the housing less than the second threshold, in preference to the corrected air ratio.

3. 3. The control device according to claim 1, wherein the first air ratio is calculated by feedforward control so that the air ratio under the preset conditions follows changes in the temperature and pressure of the air supplied to the combustion device.

4. 3. The control device according to claim 1, wherein the predetermined reference value is a concentration of the unburned gaseous fuel in the exhaust gas after combustion of the air-fuel mixture of 0%.

5. 1. A control device for controlling a supply amount of a gaseous fuel or air used in a combustion device that burns a mixture of a carbon-free gaseous fuel and air, comprising: correcting the air ratio calculated by feedforward control so that the air ratio under preset conditions follows a change in the temperature of the air supplied to the combustion device with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust after combustion of the mixture becomes a preset reference value; and controlling the supply amount of the gaseous fuel or the air based on the corrected air ratio obtained by correcting the calculated air ratio with the correction value; A control device that, when the temperature of a housing to which the gaseous fuel and the air in the combustion device are supplied, obtained during combustion of the mixture, is equal to or higher than a predetermined threshold, controls the supply amount of the gaseous fuel or the air based on an air ratio that makes the temperature of the housing, calculated in advance, less than the threshold, in priority to the corrected air ratio.

6. a first supply line for supplying the air; a first valve provided in the first supply line to adjust the amount of air supplied; a second supply line for supplying the gaseous fuel; a second valve provided in the second supply line to adjust the supply amount of the gaseous fuel; a first detector for detecting the temperature of the air; a second detection unit that detects the concentration of the unburned gaseous fuel; The control device according to claim 1 or 5, which controls the first valve or the second valve; a burner connected to the first supply line and the second supply line; a housing in which the burner is provided; A combustion device comprising:

7. 1. A control method for controlling a supply amount of a gaseous fuel or air used in a combustion device that burns a mixture of the gaseous fuel and air that does not contain carbon, comprising: a step of correcting the air ratio calculated by feedforward control so that the air ratio under preset conditions follows a change in the temperature of the air supplied to the combustion device with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from exhaust gas after combustion of the air-fuel mixture becomes a preset reference value, and controlling the supply amount of the gaseous fuel or the air based on the corrected air ratio obtained by correcting the calculated air ratio with the correction value; When a concentration of nitrogen oxides obtained from exhaust gas after combustion of the air-fuel mixture is equal to or greater than a predetermined threshold value, controlling the supply amount of the gaseous fuel or the air based on a pre-calculated air ratio at which the concentration of nitrogen oxides becomes less than the threshold value, with priority over the corrected air ratio; A control method comprising:

8. A control program for controlling a supply amount of the gaseous fuel or the air, used in a combustion device that burns a mixture of the gaseous fuel and air that does not contain carbon, comprising: a process of correcting the air ratio calculated by feedforward control so that the air ratio under preset conditions follows a change in the temperature of the air supplied to the combustion device with a correction value calculated by feedback control so that the concentration of unburned gaseous fuel obtained from the exhaust gas after combustion of the air-fuel mixture becomes a preset reference value, and controlling the supply amount of the gaseous fuel or the air based on the corrected air ratio obtained by correcting the calculated air ratio with the correction value; and when the concentration of nitrogen oxides obtained from the exhaust gas after combustion of the air-fuel mixture is equal to or higher than a predetermined threshold, controlling the supply amount of the gaseous fuel or the air based on a pre-calculated air ratio at which the concentration of nitrogen oxides is less than the threshold, taking priority over the corrected air ratio.

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