Fuel supply device for co-firing and fuel supply method in a fuel supply device for co-firing

Abstract

The present invention provides a fuel supply system for co-firing equipped with a bypass fuel supply pipe, which allows for easy adjustment of the fuel flow rate by maintaining the heat ratio of each fuel to a set heat ratio for each fuel, and a fuel supply method for a co-firing fuel supply system. [Solution] The fuel supply device 30 for co-firing according to the embodiment includes a hydrogen supply system 40 that supplies hydrogen gas to the combustion device 200, comprising a main fuel supply pipe 41 having a flow control valve 45 and a bypass fuel supply pipe 42 having a flow control valve 46 and bypassing the flow control valve 45 to connect to the main fuel supply pipe 41; a city gas supply system 70 that supplies city gas to the combustion device 200, comprising a main fuel supply pipe 71 having a flow control valve 75 and a bypass fuel supply pipe 72 having a flow control valve 76 and bypassing the flow control valve 75 to connect to the main fuel supply pipe 71; and a control device 90 for adjusting the flow rates of hydrogen gas and city gas.

Description

Technical Field

[0001] Embodiments of the present invention relate to a fuel supply device for co-firing and a fuel supply method in the fuel supply device for co-firing.

Background Art

[0002] In conventional combustion devices, there are co-firing combustion devices that burn a plurality of different fuels. The ratio of the calorific value of each fuel burned in this co-firing combustion device is shown as a calorific value ratio. And the calorific value ratio for each fuel is arbitrarily set in advance as a set calorific value ratio. When hydrogen and city gas are used as fuels, for example, the set calorific value ratio is set in consideration of the emissions of NOx and CO2, misfire conditions, etc. And in order to achieve the set calorific value ratio, the flow rate of each fuel supplied to the co-firing combustion device is adjusted.

[0003] In the co-firing combustion device, each fuel is supplied by a fuel supply device for co-firing. In the fuel supply device for co-firing, the flow rate of each fuel is generally adjusted by a valve. As this valve, electric valves such as an electric ball valve and an electric butterfly valve are widely used.

[0004] The fuel supply system in the fuel supply device for co-firing includes a fuel supply system with a bypass fuel supply pipe that includes a main fuel supply pipe equipped with an electric valve and a bypass fuel supply pipe provided so as to bypass the electric valve of the main fuel supply pipe. Note that the bypass fuel supply pipe is also equipped with an electric valve. In this case, for example, the bypass fuel supply pipe is used as a supply system that flows a fuel with a smaller flow rate than the main fuel supply pipe. Therefore, the electric valve provided in the bypass fuel supply pipe uses a small-flow electric valve suitable for adjusting a small flow rate. On the other hand, the electric valve provided in the main fuel supply pipe uses a large-flow electric valve suitable for adjusting a large flow rate.

[0005] In such a fuel supply system with a bypass fuel supply pipe, when the fuel flow rate is low, the large-flow electric valve is closed, and the fuel flow rate is adjusted only by the small-flow electric valve.

[0006] On the other hand, when the fuel flow rate is high, for example, the low-flow electric valve is closed, and the fuel flow rate is regulated only by the high-flow electric valve. Also, when the fuel flow rate is high, for example, the low-flow electric valve is fully opened, and the fuel flow rate is regulated only by the high-flow electric valve.

[0007] Figure 8 illustrates the intrinsic flow rate characteristics of a typical electric valve, showing the relationship between valve opening and flow rate. Here, the intrinsic flow rate characteristics of electric valves 300A and 300B are shown as examples. As shown in Figure 8, the flow rate does not change linearly with respect to the valve opening, but rather changes curvilinearly. Such intrinsic flow rate characteristics are typical for electric valves.

[0008] Specifically, the intrinsic flow rate characteristics of the electric valve 300A are such that, for example, as shown by curve A in Figure 8, the change in flow rate is small when the valve opening is small, and the change in flow rate increases as the valve opening increases. On the other hand, the intrinsic flow rate characteristics of the electric valve 300B are such that, for example, as shown by curve B in Figure 8, the change in flow rate is large when the valve opening is small, and the change in flow rate decreases as the valve opening increases. Therefore, in fuel supply systems equipped with electric valves, flow rate control is performed after understanding the intrinsic flow rate characteristics of the electric valves as described above.

[0009] Here, in cases where the flow rate changes curvilinearly with respect to the valve opening, as in the case of electric valves 300A and 300B, it is also possible to adjust the valve opening by controlling the current input as a control signal to electric valves 300A and 300B, thereby changing the flow rate linearly with respect to the valve opening, as shown by the dashed line C in Figure 8.

[0010] In a fuel supply system for co-firing, the flow rate of each fuel is adjusted based on the inherent flow characteristics of the electric valves described above, in order to set the heat ratio of each fuel to the desired heat ratio. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2024-87190 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] As described above, the intrinsic flow characteristics of the electric valve change curvilinearly with respect to the valve opening, as shown in Figure 8. Here, Figure 9 illustrates the relationship between the output in a conventional mixed-combustion combustion device and the fuel flow rate in a fuel supply system with a bypass fuel supply pipe. In Figure 9, the output refers to the total amount of heat generated by the combustion of each fuel in the mixed-combustion combustion device. The fuel flow rate refers to the fuel flow rate of a particular type of fuel in a fuel supply system with a bypass fuel supply pipe.

[0013] In Figure 9, when the output is below H1, the high-flow electric valve is closed and the fuel flow rate is regulated by the low-flow electric valve. When the output is greater than H1, the low-flow electric valve is closed and the fuel flow rate is regulated by the high-flow electric valve. Figure 9 also shows an example in which the valve opening is adjusted by controlling the control current for the low-flow and high-flow electric valves, and the flow rate is changed linearly with respect to the valve opening, as shown by the dashed line C in Figure 8.

[0014] As shown in Figure 9, even when the flow rate is changed linearly with respect to the valve opening by controlling the electric valves for low flow rate and high flow rate, when the electric valve that adjusts the flow rate is switched (when the output is H1), the change in flow rate with respect to the output may exhibit a curved characteristic. In other words, there is a point (bending point 310) where the slope of the linear relationship between the output and the flow rate changes.

[0015] Such a bending point 310 also occurs in the relationship between the fuel flow rate in a fuel supply system with a bypass fuel supply pipe for other fuels and the output in a mixed-combustion combustion device. Furthermore, the output at which the bending point 310 occurs differs for each fuel.

[0016] Furthermore, the flow rate change characteristics with respect to output shown in Figure 9 are similar to those obtained when the low-flow electric valve is fully open and the fuel flow rate is adjusted by the high-flow electric valve, on the side where the output is greater than H1.

[0017] In a mixed-fuel combustion system, control is performed to increase or decrease the output while maintaining the heat ratio of each fuel at a set heat ratio for each fuel. In this case, with the flow rate change characteristics with respect to output as shown in Figure 9, controlling the output to increase or decrease while maintaining a constant heat ratio becomes more complicated compared to a characteristic where the total flow rate changes along a straight line with respect to output (linear characteristic).

[0018] Here, Figure 10 illustrates the relationship between the output of a conventional mixed-combustion combustion device and the fuel flow rate in the fuel supply system with a bypass fuel supply pipe for the first fuel and the fuel supply system with a bypass fuel supply pipe for the second fuel.

[0019] Here, H2 and H3 on the horizontal axis of Figure 10 represent the inputs when switching from flow rate adjustment using a small-flow electric valve to flow rate adjustment using a large-flow electric valve, for example.

[0020] As shown in Figure 10, for the first fuel, the slope of the straight line representing the flow rate of the first fuel relative to the output changes with input H3. Similarly, for the second fuel, the slope of the straight line representing the flow rate of the second fuel relative to the output changes with input H2.

[0021] When the output is below H2, the heat ratio of each fuel is maintained at the set heat ratio for each fuel, while the flow rates of the first fuel and the second fuel change with respect to the output.

[0022] On the other hand, on the side where the slope of the straight line is greater than the input H2, when the flow rates of the first fuel and the second fuel are changed relative to the output, the heat ratio of each fuel does not maintain the set heat ratio for each fuel. In this case, complicated adjustments of the flow rates of the first fuel and the second fuel are required to maintain the heat ratio at the set heat ratio.

[0023] The problem to be solved by the present invention is to provide a fuel supply device for co-firing that includes a fuel supply system with a bypass fuel supply pipe, and that can easily adjust the fuel flow rate while maintaining the calorific value ratio of each fuel at the set calorific value ratio for each fuel, as well as a fuel supply method in the fuel supply device for co-firing.

Means for Solving the Problem

[0024] The fuel supply device for co-firing in the embodiment supplies fuel to a combustion device capable of co-firing a plurality of fuels. The fuel supply device for co-firing includes a first fuel supply system that supplies a first fuel, a second fuel supply system that supplies a second fuel, and a control device for adjusting the flow rates of the first fuel and the second fuel.

[0025] The first fuel supply system includes a first main fuel supply pipe provided with a first flow rate adjustment valve for adjusting the flow rate of the first fuel, a second flow rate adjustment valve for adjusting the flow rate of the first fuel, a first bypass fuel supply pipe that bypasses the first flow rate adjustment valve and is connected to the first main fuel supply pipe, and a first heat quantity ratio adjustment valve provided in the first main fuel supply pipe between the combustion device and the first connection portion on the combustion device side among the connection portions of the first bypass fuel supply pipe and the first main fuel supply pipe, and having a valve opening degree set based on a set heat quantity ratio indicating the ratio of the calorific values of each fuel in the combustion device set in advance.

[0026] The second fuel supply system includes a second main fuel supply pipe provided with a third flow rate adjustment valve for adjusting the flow rate of the second fuel, a fourth flow rate adjustment valve for adjusting the flow rate of the second fuel, a second bypass fuel supply pipe that bypasses the third flow rate adjustment valve and is connected to the second main fuel supply pipe, and a second heat quantity ratio adjustment valve provided in the second main fuel supply pipe between the combustion device and the second connection portion on the combustion device side among the connection portions of the second bypass fuel supply pipe and the second main fuel supply pipe, and having a valve opening degree set based on the set heat quantity ratio.

[0027] The control device is set based on the types of the first fuel and the second fuel, the set calorific value ratio, the first flow rate adjustment valve, the second flow rate adjustment valve, the third flow rate adjustment valve, and the fourth flow rate adjustment valve, the specific flow rate characteristics indicating the relationship between the valve opening degree and the flow rate, and the opening degree characteristics indicating the relationship between the commanded valve opening degree and the adjusted valve opening degree in the first flow rate adjustment valve, the second flow rate adjustment valve, the third flow rate adjustment valve, and the fourth flow rate adjustment valve. The flow rate of the first fuel with respect to the output corresponding to the calorific value generated in the combustion device and the flow rate of the second fuel with respect to the output change while maintaining the set calorific value ratio. Valve control data for controlling the first flow rate adjustment valve, the second flow rate adjustment valve, the third flow rate adjustment valve, and the fourth flow rate adjustment valve, a valve control data selection unit that selects corresponding data from the valve control data based on the types of the first fuel and the second fuel, the set calorific value ratio, the first flow rate adjustment valve, the second flow rate adjustment valve, the third flow rate adjustment valve, and the fourth flow rate adjustment valve, a temperature determination unit that determines whether the temperature of the combustion exhaust gas discharged from the combustion device is a preset set temperature, and when the temperature determination unit determines that the temperature of the combustion exhaust gas is not the set temperature, based on the data selected by the valve control data selection unit, a valve control unit that controls the first flow rate adjustment valve, the second flow rate adjustment valve, the third flow rate adjustment valve, and the fourth flow rate adjustment valve to adjust the temperature of the combustion exhaust gas to the set temperature.

[0028] Further, in a fuel supply method of a fuel supply device for co-firing a plurality of fuels in an embodiment of a combustion device capable of co-firing, the fuel supply device for co-firing includes a first fuel supply system that supplies a first fuel, a second fuel supply system that supplies a second fuel, and a control device for adjusting the flow rates of the first fuel and the second fuel.

[0029] The first fuel supply system includes a first main fuel supply pipe equipped with a first flow control valve for adjusting the flow rate of the first fuel, a first bypass fuel supply pipe equipped with a second flow control valve for adjusting the flow rate of the first fuel and connected to the first main fuel supply pipe by bypassing the first flow control valve, and a first heat ratio adjustment valve provided in the first main fuel supply pipe between the combustion device and the first connection portion on the combustion device side of the connection portion between the first bypass fuel supply pipe and the first main fuel supply pipe, the valve opening degree of which is set based on a set heat ratio indicating the ratio of the calorific values ​​of each fuel in the combustion device which is set in advance.

[0030] The second fuel supply system comprises a second main fuel supply pipe equipped with a third flow control valve for adjusting the flow rate of the second fuel, a second bypass fuel supply pipe equipped with a fourth flow control valve for adjusting the flow rate of the second fuel and connected to the second main fuel supply pipe by bypassing the third flow control valve, and a second heat ratio adjustment valve provided in the second main fuel supply pipe between the second connection portion on the combustion device side of the connection portion between the second bypass fuel supply pipe and the second main fuel supply pipe and the combustion device, the valve opening degree of which is set based on the set heat ratio.

[0031] The control device is set based on the types of the first and second fuels, the set heat ratio, the intrinsic flow characteristics showing the relationship between valve opening and flow rate in the first, second, third, and fourth flow control valves, and the opening characteristics showing the relationship between command valve opening and control valve opening in the first, second, third, and fourth flow control valves, and controls the first, second, third, and fourth flow control valves so that the flow rate of the first fuel and the flow rate of the second fuel relative to the output corresponding to the heat amount in the combustion device change while maintaining the set heat ratio. The control device stores valve control data for the purpose of controlling the combustion gas, and based on the types of the first and second fuels, the set heat ratio, and the types of the first, second, third, and fourth flow control valves, it selects corresponding data from the valve control data. The control device determines whether the temperature of the combustion exhaust gas discharged from the combustion device is a preset temperature, and if it determines that the temperature of the combustion exhaust gas is not the preset temperature, the control device controls the first, second, third, and fourth flow control valves based on the data selected from the valve control data to adjust the temperature of the combustion exhaust gas to the preset temperature. [Effects of the Invention]

[0032] According to the fuel supply device for co-firing and the fuel supply method in the fuel supply device for co-firing of the present invention, in a fuel supply device for co-firing equipped with a fuel supply system with a bypass fuel supply pipe, it becomes possible to easily adjust the fuel flow rate while maintaining the heat ratio of each fuel to the set heat ratio for each fuel. [Brief explanation of the drawing]

[0033] [Figure 1] This diagram schematically shows the configuration of a combustion system equipped with a fuel supply device for co-firing according to the embodiment. [Figure 2]This is a block diagram showing the configuration of the control device in the fuel supply device for co-firing according to the embodiment. [Figure 3] This figure shows an example of the intrinsic flow rate characteristics, illustrating the relationship between valve opening and flow rate in a flow control valve provided in a fuel supply device for co-firing according to the embodiment. [Figure 4] This figure shows an example of the opening characteristics that illustrate the relationship between the command valve opening and the control valve opening in a flow control valve provided in a fuel supply device for co-firing according to the embodiment. [Figure 5] This figure shows an example of the relationship between the output of a combustion device and the flow rate of each fuel in a fuel supply device for co-firing according to the embodiment. [Figure 6] This is a flowchart illustrating the fuel supply method of the fuel supply device for co-firing according to the embodiment. [Figure 7] This is a flowchart illustrating the process related to the heat ratio in the fuel supply method of the fuel supply device for co-firing according to the embodiment. [Figure 8] This figure illustrates the intrinsic flow characteristics, showing the relationship between valve opening and flow rate in a typical electric valve. [Figure 9] This diagram illustrates the relationship between the output of a conventional mixed-combustion combustion system and the fuel flow rate in a fuel supply system with a bypass fuel supply pipe. [Figure 10] This diagram illustrates the relationship between the output of a conventional mixed-combustion combustion system and the fuel flow rates in the fuel supply system with a bypass fuel supply pipe for the first fuel and the fuel supply system with a bypass fuel supply pipe for the second fuel. [Modes for carrying out the invention]

[0034] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0035] Figure 1 is a schematic diagram showing the configuration of a combustion device system 1 equipped with a co-firing fuel supply device 30 according to an embodiment.

[0036] As shown in Figure 1, the combustion system 1 comprises a co-firing oxidizer supply device 10, a co-firing fuel supply device 30, and a combustion device 200.

[0037] (Combustion device 200) First, let me explain the combustion device 200.

[0038] The combustion device 200 is a mixed-combustion type combustion device capable of co-combusting multiple fuels. Here, as an example of the combustion device 200, a diffusion combustion type combustor in which two types of fuel and an oxidizer are injected separately into the combustion chamber 210 is used for explanation. However, the combustion method of the combustion device 200 is not limited to this, and other combustion methods such as a premixed combustion method may also be used.

[0039] The combustion device 200 includes a combustion chamber 210, a first fuel injection unit 220, a second fuel injection unit 221, an oxidizer injection unit 230, a combustion exhaust gas return system 270, and a temperature sensor 240. The combustion device 200 may also include, for example, a pilot burner 250.

[0040] The combustion chamber 210 is a cylindrical body in which fuel and oxidizer are burned. A flame is formed inside the combustion chamber 210.

[0041] The first fuel injection unit 220 injects the first fuel into the combustion chamber 210. The first fuel injection unit 220 is composed of, for example, a tubular member. The first fuel injection unit 220 is provided, for example, at one end of the combustion chamber 210.

[0042] The oxidizer injection unit 230 injects an oxidizer into the combustion chamber 210. The oxidizer injection unit 230 is composed of, for example, an annular flow path between a tubular member constituting the first fuel injection unit 220 and a tubular member surrounding the outer circumference of the oxidizer injection unit 230. The tubular member surrounding the outer circumference of the first fuel injection unit 220 is provided, for example, at one end of the combustion chamber 210.

[0043] The second fuel injection section 221 injects a second fuel into the combustion chamber 210. The second fuel injection section 221 is composed of, for example, an annular flow path between a tubular member constituting an oxidizer injection section 230 and a tubular member surrounding the outer circumference of the second fuel injection section 221. The tubular member surrounding the outer circumference of the oxidizer injection section 230 is provided, for example, at one end of the combustion chamber 210.

[0044] The arrangement of the first fuel injection section 220, the second fuel injection section 221, and the oxidizer injection section 230 is not limited to these, and the arrangement may be changed as appropriate according to the application. The first fuel injection section 220, the second fuel injection section 221, and the oxidizer injection section 230 constitute the main burner 235.

[0045] Here, the state of the fuel supplied to the first fuel injection unit 220 and the second fuel injection unit 221 is gaseous. For example, hydrogen is used as the first fuel, and a gas mainly composed of methane is used as the second fuel. Here, an example is shown in which hydrogen is used as the first fuel and city gas is used as the second fuel. Note that the first and second fuels are not limited to these. The first and second fuels can be appropriately selected and combined from widely used fuel gases depending on the purpose. For example, hydrogen and a hydrocarbon gas, or a hydrocarbon gas and a hydrocarbon gas different from this hydrocarbon gas may be combined as the first and second fuels.

[0046] An example using air as an oxidizing agent is shown, but oxygen or other substances may also be used.

[0047] The combustion chamber 210 outlet and the combustion gas utilization section 290, which utilizes the combustion gas, are connected by a combustion gas exhaust pipe 260. The combustion gas exhaust pipe 260 is equipped with a blower 261, such as a fan. The blower 261 guides the combustion exhaust gas from the combustion chamber 210 to the combustion gas utilization section 290 via the combustion gas exhaust pipe 260. The blower 261 is composed of, for example, a sirocco fan or a turbo fan.

[0048] The combustion exhaust gas return system 270 has the function of extracting a portion of the combustion exhaust gas used in the combustion gas utilization section 290, and mixing air with the extracted combustion exhaust gas and returning it to the combustion chamber 210. Specifically, the combustion exhaust gas return system 270 includes a return pipe 271 and an atmospheric inlet pipe 272.

[0049] The return pipe 271 returns a portion of the combustion exhaust gas, after it has been used in the combustion gas utilization section 290, back into the combustion chamber 210. One end of the return pipe 271 is provided to communicate with the space in the combustion gas utilization section 290 that utilizes the combustion exhaust gas. The other end of the return pipe 271 is connected to the combustion chamber 210. The other end of the return pipe 271 is positioned so as not to interfere with the combustion reaction in the main burner 235.

[0050] An atmospheric intake pipe 272 is connected to the other end of the return pipe 271. One end of the atmospheric intake pipe 272 is open to the atmosphere. The atmospheric intake pipe 272 is a pipe for introducing atmospheric air into the combustion exhaust gas that is returned to the combustion chamber 210 from the combustion gas utilization section 290 via the return pipe 271. In other words, atmospheric air is drawn in from the open end of the atmospheric intake pipe 272 and introduced into the return pipe 271.

[0051] The atmospheric intake pipe 272 is equipped with a flow rate adjustment section 273 for adjusting the flow rate of air introduced into the return pipe 271. This flow rate adjustment section 273 is composed of, for example, a damper. The opening of the damper is adjusted, for example, so that a constant flow rate of air is introduced into 271.

[0052] In other words, the combustion exhaust gas discharged from the combustion chamber 210 to the combustion gas exhaust pipe 260 is a mixture of combustion gas produced by the combustion of fuel and oxidizer in the combustion chamber 210 and combustion exhaust gas containing air that is returned to the combustion chamber 210 from the return pipe 271.

[0053] Here, the blower 261 provided in the combustion gas exhaust pipe 260 has the function of introducing combustion exhaust gas from the combustion chamber 210 to the combustion gas utilization section 290 via the combustion gas exhaust pipe 260, and the function of returning the combustion exhaust gas from the combustion gas utilization section 290 to the combustion chamber 210 via the return pipe 271.

[0054] The temperature sensor 240 detects the temperature of the combustion exhaust gas at the outlet of the combustion chamber 210. The temperature sensor 240 is installed, for example, at the inlet of the combustion gas exhaust pipe 260, which is the outlet of the combustion chamber 210. The temperature sensor 240 detects the temperature of the mixed gas consisting of the combustion gas and the combustion exhaust gas containing the atmosphere.

[0055] The pilot burner 250 is used, for example, when igniting the main burner 235. The pilot burner 250 is supplied with, for example, a mixture of a first fuel and a second fuel, and an oxidizer. The fuel ejected from the pilot burner 250 is ignited using an ignition device such as an igniter (not shown). Alternatively, the main burner 235 may be equipped with an ignition device instead of a pilot burner 250. (Oxidizing agent supply device for co-firing 10) Next, the co-firing oxidizer supply device 10 will be described.

[0056] The co-firing oxidizer supply device 10 supplies oxidizer to the combustion device 200. The co-firing oxidizer supply device 10 includes a main burner oxidizer supply pipe 11, an oxidizer supply source 13, and flow control valves 14 and 15. If a pilot burner 250 is provided, the co-firing oxidizer supply device 10 also includes a pilot oxidizer supply pipe 12 and a flow control valve 16.

[0057] The main burner oxidizer supply pipe 11 supplies oxidizer to the main burner 235. One end of the main burner oxidizer supply pipe 11 is connected to the oxidizer discharge section 230, and the other end of the main burner oxidizer supply pipe 11 is connected to the oxidizer supply source 13. The main burner oxidizer supply pipe 11 is equipped with flow control valves 14 and 15 to adjust the flow rate of the oxidizer.

[0058] The pilot oxidizer supply pipe 12 supplies oxidizer to the pilot burner 250. One end of the pilot oxidizer supply pipe 12 is connected to the pilot burner 250. The other end of the pilot oxidizer supply pipe 12 is connected to the main burner oxidizer supply pipe 11 between the flow control valve 15 on the oxidizer supply source 13 side and the oxidizer supply source 13. The pilot oxidizer supply pipe 12 is equipped with a flow control valve 16 for adjusting the flow rate of the oxidizer.

[0059] The oxidizing agent source 13 consists of, for example, a fan, a blower, a compressor, etc. If the oxidizing agent is oxygen, the oxidizing agent source 13 consists of, for example, an oxygen cylinder that stores high-pressure oxygen.

[0060] (Mixed combustion fuel supply device 30) Next, the fuel supply device 30 for co-firing will be described.

[0061] Here, we will explain using an example where hydrogen gas (H2) is used as the first fuel and city gas (13A) is used as the second fuel.

[0062] The co-firing fuel supply device 30 is a fuel supply device capable of supplying multiple types of fuel to a co-firing combustion device 200. In this case, the co-firing fuel supply device 30 supplies hydrogen gas and city gas to the combustion device 200.

[0063] The co-firing fuel supply system 30 comprises a hydrogen supply system 40, a city gas supply system 70, and a control device 90. The hydrogen supply system 40 functions as the first fuel supply system, and the city gas supply system 70 functions as the second fuel supply system.

[0064] (Hydrogen supply system 40) First, let me explain the hydrogen supply system 40.

[0065] The hydrogen supply system 40 supplies hydrogen gas to the combustion device 200. The hydrogen supply system 40 includes a main fuel supply pipe 41, a bypass fuel supply pipe 42, and a hydrogen supply source 49. The main fuel supply pipe 41 functions as the first main fuel supply pipe, and the bypass fuel supply pipe 42 functions as the first bypass fuel supply pipe.

[0066] Furthermore, if a pilot burner 250 is provided, the hydrogen supply system 40 includes a pilot fuel supply pipe 55. In addition, the hydrogen supply system 40 may also include a purge gas supply pipe 60 for supplying purge gas to the combustion device 200 and a nitrogen gas supply source 61.

[0067] Here, the configuration of supplying purge gas to the combustion device 200 is preferably applied when using fuels that have a fast combustion rate, such as hydrogen, and are prone to flashback, for example, when shutting off the fuel supply. However, when using fuels that do not have a flashback problem, the configuration of supplying purge gas to the combustion device 200 is not required.

[0068] One end of the main fuel supply pipe 41 is connected to the first fuel injection section 220, and the other end of the main fuel supply pipe 41 is connected to the hydrogen supply source 49. The main fuel supply pipe 41 is equipped with, in order from the hydrogen supply source 49 side, a flow sensor 48, a governor 47, a shut-off valve 44, a flow control valve 45, and a heat ratio adjustment valve 43.

[0069] The flow detector 48 detects the flow rate of hydrogen gas supplied to the combustion device 200. If a pilot burner 250 is provided, the flow rate detected by the flow detector 48 will be the flow rate supplied to the main burner 235 and the pilot burner 250.

[0070] The governor 47 adjusts the pressure of the hydrogen gas supplied from the hydrogen source 49 to flow the hydrogen gas to the combustion device 200 at a predetermined pressure. The shut-off valve 44 opens and closes the valve to allow the hydrogen gas to flow or to shut off the flow of hydrogen gas.

[0071] The flow control valve 45 adjusts the flow rate of hydrogen gas supplied to the first fuel injection section 220 through the main fuel supply pipe 41. An electric valve such as an electric ball valve or an electric butterfly valve is used as the flow control valve 45. The flow control valve 45 functions as the first flow control valve.

[0072] The heat ratio adjustment valve 43 allows hydrogen gas to pass through at a flow rate that satisfies the set heat ratio for hydrogen gas. Here, the set heat ratio represents the ratio of the calorific values ​​of each fuel in the combustion device 200, which is set in advance. The valve opening of the heat ratio adjustment valve 43 is set based on the set heat ratio for hydrogen gas. As a result, the flow rate of hydrogen gas supplied to the combustion device 200 becomes a flow rate that satisfies the set heat ratio for hydrogen gas. In other words, the amount of heat generated by the combustion of hydrogen gas that has passed through the heat ratio adjustment valve 43 is equal to the set heat ratio for hydrogen gas. The heat ratio adjustment valve 43 functions as a first heat ratio adjustment valve.

[0073] The bypass fuel supply pipe 42 bypasses the flow control valve 45 and is connected to the main fuel supply pipe 41. Specifically, one end of the bypass fuel supply pipe 42 is connected to the main fuel supply pipe 41 between the shut-off valve 44 and the flow control valve 45 via a connecting section C1, and the other end of the bypass fuel supply pipe 42 is connected to the main fuel supply pipe 41 between the heat ratio adjustment valve 43 and the flow control valve 45 via a connecting section C2.

[0074] The bypass fuel supply pipe 42 is equipped with a flow control valve 46. The flow control valve 46 adjusts the flow rate of hydrogen gas supplied to the first fuel injection section 220 through the bypass fuel supply pipe 42 and the main fuel supply pipe 41. An electric valve such as an electric ball valve or an electric butterfly valve is used as the flow control valve 46. The flow control valve 46 also functions as a second flow control valve.

[0075] Here, for example, the bypass fuel supply pipe 42 is used as a supply system that carries a smaller flow rate of fuel than the main fuel supply pipe 41. Therefore, the flow control valve 46 provided in the bypass fuel supply pipe 42 is a small-flow electric valve suitable for adjusting small flow rates. On the other hand, the flow control valve 45 provided in the main fuel supply pipe 41 is a large-flow electric valve suitable for adjusting large flow rates.

[0076] In this embodiment, the fuel flow rate is adjusted by controlling the valve openings of both the flow control valve 45 and the flow control valve 46, regardless of the fuel flow rate. As will be explained in more detail later, this results in a relationship between the output of the combustion device 200 and the fuel flow rate that changes along a predetermined straight line.

[0077] Furthermore, for example, by configuring the flow control valve 46 with a small flow rate electric valve and the flow control valve 45 with a large flow rate electric valve, it becomes possible to adjust the fuel flow rate in the range from small to large flow rates, and a wide turndown ratio (TDR) can be obtained. The turndown ratio (TDR) is the ratio of the minimum controllable flow rate to the maximum controllable flow rate.

[0078] The pilot fuel supply pipe 55 supplies a portion of the hydrogen gas flowing through the main fuel supply pipe 41 to the pilot mixed fuel supply pipe 58, which supplies mixed fuel to the pilot burner 250. One end of the pilot fuel supply pipe 55 is connected to the main fuel supply pipe 41 between the governor 47 and the shut-off valve 44. The other end of the pilot fuel supply pipe 55 is connected to the pilot mixed fuel supply pipe 58.

[0079] The pilot fuel supply pipe 55 is equipped with a shut-off valve 56 and a flow control valve 57. The shut-off valve 56 opens and closes to allow hydrogen gas to flow or to shut off the flow of hydrogen gas. The flow control valve 57 adjusts the flow rate of hydrogen gas supplied through the pilot fuel supply pipe 55 to the pilot mixed fuel supply pipe 58.

[0080] Here, we show an example in which hydrogen gas and city gas are mixed in the pilot fuel supply pipe 58 and supplied to the pilot burner 250, but the configuration is not limited to this. Hydrogen gas may be supplied directly to the pilot burner 250 via the pilot fuel supply pipe 55. City gas may also be supplied directly to the pilot burner 250 via the pilot fuel supply pipe 80, which will be described later.

[0081] The purge gas supply pipe 60 supplies an inert gas to the hydrogen supply system 40 to prevent flame flashback, for example, when stopping the supply of hydrogen gas to the first fuel injection section 220. Examples of inert gases that can be used include nitrogen gas, argon gas, and helium gas. Here, an example using nitrogen gas as the inert gas is shown.

[0082] One end of the purge gas supply pipe 60 is connected to the nitrogen gas supply source 61. The other end of the purge gas supply pipe 60 branches into a purge gas supply pipe 62 for the main burner and a purge gas supply pipe 63 for the pilot burner.

[0083] The end of the branched main burner purge gas supply pipe 62 is connected to the main fuel supply pipe 41 at the connection section C1. The main burner purge gas supply pipe 62 is equipped with a shut-off valve 64 and a flow control valve 65. The shut-off valve 64 opens and closes to allow or block the flow of nitrogen gas. The flow control valve 65 adjusts the flow rate of nitrogen gas supplied to the first fuel injection section 220 via the main burner purge gas supply pipe 62 and the main fuel supply pipe 41, or via the main burner purge gas supply pipe 62, the bypass fuel supply pipe 42, and the main fuel supply pipe 41.

[0084] The branched purge gas supply pipe 63 for the pilot burner is connected to the pilot fuel supply pipe 55 between the shut-off valve 56 and the flow control valve 57. The purge gas supply pipe 63 for the pilot burner includes a shut-off valve 66 and a flow control valve 67. The shut-off valve 66 opens and closes to allow or block the flow of nitrogen gas. The flow control valve 67 adjusts the flow rate of nitrogen gas supplied to the pilot burner 250 via the purge gas supply pipe 63 for the pilot burner and the pilot mixed fuel supply pipe 58.

[0085] (City gas supply system 70) Next, we will explain the city gas supply system 70.

[0086] The city gas supply system 70 supplies city gas to the combustion device 200. The city gas supply system 70 includes a main fuel supply pipe 71, a bypass fuel supply pipe 72, and a city gas supply source 78. The main fuel supply pipe 71 functions as a second main fuel supply pipe, and the bypass fuel supply pipe 72 functions as a second bypass fuel supply pipe.

[0087] Furthermore, if a pilot burner 250 is provided, the city gas supply system 70 is equipped with a pilot fuel supply pipe 80.

[0088] One end of the main fuel supply pipe 71 is connected to the second fuel injection section 221, and the other end of the main fuel supply pipe 71 is connected to the city gas supply source 78. The main fuel supply pipe 71 is equipped with, in order from the city gas supply source 78 side, a flow sensor 77, a shut-off valve 74, a flow control valve 75, and a heat ratio adjustment valve 73.

[0089] The flow detector 77 detects the flow rate of city gas supplied to the combustion device 200. If a pilot burner 250 is provided, the flow rate detected by the flow detector 77 will be the flow rate supplied to the main burner 235 and the pilot burner 250.

[0090] The shut-off valve 74 opens and closes to allow or block the flow of city gas.

[0091] The flow control valve 75 adjusts the flow rate of city gas supplied to the second fuel injection section 221 through the main fuel supply pipe 71. An electric valve such as an electric ball valve or an electric butterfly valve is used as the flow control valve 75. The flow control valve 75 also functions as a third flow control valve.

[0092] Here, for example, the bypass fuel supply pipe 72 is used as a supply system that carries a smaller flow rate of fuel than the main fuel supply pipe 71. Therefore, the flow control valve 76 provided in the bypass fuel supply pipe 72 is a small-flow electric valve suitable for adjusting small flow rates. On the other hand, the flow control valve 75 provided in the main fuel supply pipe 71 is a large-flow electric valve suitable for adjusting large flow rates.

[0093] In this embodiment, the fuel flow rate is adjusted by controlling the valve openings of both the flow control valve 75 and the flow control valve 76, regardless of the fuel flow rate. As will be explained in more detail later, this results in a relationship between the output of the combustion device 200 and the fuel flow rate that changes along a predetermined straight line.

[0094] Furthermore, for example, by configuring the flow control valve 76 with a small flow rate electric valve and the flow control valve 75 with a large flow rate electric valve, it becomes possible to adjust the fuel flow rate in the range from small to large flow rates, thereby obtaining a wide turndown ratio (TDR).

[0095] The heat ratio adjustment valve 73 allows city gas to pass through at a flow rate that satisfies the set heat ratio for city gas. The valve opening of the heat ratio adjustment valve 73 is set based on the set heat ratio for city gas. As a result, the flow rate of city gas supplied to the combustion device 200 becomes a flow rate that satisfies the set heat ratio for city gas. In other words, the amount of heat generated by the combustion of city gas that has passed through the heat ratio adjustment valve 73 is equal to the set heat ratio for city gas. The heat ratio adjustment valve 73 also functions as a second heat ratio adjustment valve.

[0096] The bypass fuel supply pipe 72 bypasses the flow control valve 75 and is connected to the main fuel supply pipe 71. Specifically, one end of the bypass fuel supply pipe 72 is connected to the main fuel supply pipe 71 between the shut-off valve 74 and the flow control valve 75 via a connecting section C3, and the other end of the bypass fuel supply pipe 72 is connected to the main fuel supply pipe 71 between the heat ratio adjustment valve 73 and the flow control valve 75 via a connecting section C4.

[0097] The bypass fuel supply pipe 72 is equipped with a flow control valve 76. The flow control valve 76 adjusts the flow rate of city gas supplied to the second fuel injection section 221 through the bypass fuel supply pipe 72 and the main fuel supply pipe 71. An electric valve such as an electric ball valve or an electric butterfly valve is used as the flow control valve 76. The flow control valve 76 also functions as a fourth flow control valve.

[0098] The pilot fuel supply pipe 80 supplies a portion of the city gas flowing through the main fuel supply pipe 71 to the pilot mixed fuel supply pipe 58, which supplies mixed fuel to the pilot burner 250. One end of the pilot fuel supply pipe 80 is connected to the main fuel supply pipe 71 between the flow sensor 77 and the shut-off valve 74. The other end of the pilot fuel supply pipe 80 is connected to the pilot mixed fuel supply pipe 58.

[0099] The pilot fuel supply pipe 80 is equipped with a shut-off valve 81 and a flow control valve 82. The shut-off valve 81 opens and closes to allow or shut off the flow of city gas. The flow control valve 82 adjusts the flow rate of city gas supplied through the pilot fuel supply pipe 80 to the pilot mixed fuel supply pipe 58.

[0100] (Control device 90) Next, the control device 90 will be described.

[0101] The control device 90 performs control to adjust the flow rates of hydrogen gas and city gas supplied to the combustion device 200. Here, Figure 2 is a block diagram showing the configuration of the control device 90 in the co-firing fuel supply device 30 of the embodiment.

[0102] As shown in Figure 2, the control device 90 includes an input unit 100, a storage unit 110, an arithmetic unit 120, and an output unit 130.

[0103] The input unit 100 receives input signals from external input means such as control panels and input terminals used by users of the co-firing fuel supply device 30, as well as detection signals from various detectors. For example, the input unit 100 receives information from external input means such as the type and characteristics of the fuel, the set heat ratio for each fuel, and the type of flow control valve. The input unit 100 also receives detection signals from temperature detectors 240, flow detectors 48 and 77, and the like.

[0104] The storage unit 110 is implemented by, for example, a hard disk drive or non-volatile memory. The storage unit 110 stores fuel type input data 111, heat ratio input data 112, valve type input data 113, combustion exhaust gas temperature data 114, valve control data 115, and the like.

[0105] The fuel type input data 111 is data relating to the type and characteristics of the fuel supplied to the combustion device 200. Here, the fuel type input data 111 stores, for example, data relating to hydrogen gas, which is the first fuel, and city gas, which is the second fuel. Data relating to the type and characteristics of fuel input by the external input means is input by the input unit 100 and stored as fuel type input data 111 by the storage unit 110. Examples of data relating to fuel characteristics include, for example, data relating to fuel characteristics such as the higher heating value and lower heating value for each fuel.

[0106] The heat ratio input data 112 is data relating to the set heat ratio of each fuel supplied to the combustion device 200. Here, the heat ratio input data 112 stores data relating to the set heat ratio of hydrogen gas, which is the first fuel, and the set heat ratio of city gas, which is the second fuel. For example, the heat ratio input data 112 may be set to 40% for hydrogen gas and 60% for city gas. The heat ratio input data 112 can be set for various combinations of ratios. For example, the set heat ratio can be set to 0% for hydrogen gas and 100% for city gas, or 100% for hydrogen gas and 0% for city gas. In other words, the set heat ratios for hydrogen gas and city gas can be set in the range of 0-100% as the heat ratio input data 112.

[0107] Furthermore, data regarding the set heat ratio of each fuel, input via external input means, is input by the input unit 100 and stored as heat ratio input data 112 by the storage unit 110.

[0108] Furthermore, the calorific value ratio input data 112 also stores data on the fuel flow rate ratio of each fuel corresponding to the set calorific value ratio of each fuel, for example. Specifically, for a combination of hydrogen gas and city gas, it stores the fuel flow rate ratios of hydrogen gas and city gas to set the set calorific value ratio for hydrogen gas to 40% and the set calorific value ratio for city gas to 60%.

[0109] The valve type input data 113 is data relating to the types of flow control valves and the like provided in the co-firing fuel supply device 30. The valve type input data 113 stores data relating to valve types such as flow control valves 45, 46, 75, 76 and heat ratio adjustment valves 43, 73. The valve type data also stores specifications such as the valve manufacturer and valve model. At least information that can identify the valve is stored in the valve type data. Note that valve type data input via external input means is input by the input unit 100 and stored as valve type input data 113 by the storage unit 110.

[0110] The combustion exhaust gas temperature data 114 is data relating to the set temperature of the combustion exhaust gas discharged from the combustion chamber 210 of the combustion device 200. In other words, the combustion exhaust gas temperature data 114 stores the required combustion exhaust gas temperature at the outlet of the combustion chamber 210 as the set temperature. Data relating to the set temperature of the combustion exhaust gas input by the external input means is input by the input unit 100 and stored as combustion exhaust gas temperature data 114 by the storage unit 110.

[0111] The valve control data 115 is pre-set based on the types of the first and second fuels, the set heat ratio, the intrinsic flow characteristics showing the relationship between valve opening and flow rate in the flow control valves 45, 46, 75, and 76, and the opening characteristics showing the relationship between the command valve opening and the control valve opening in the flow control valves 45, 46, 75, and 76. The valve control data 115 stores data for controlling the flow control valves 45, 46, 75, and 76 so that the flow rate of the first fuel and the flow rate of the second fuel relative to the output of the combustion device 200 change while maintaining the set heat ratio. The output of the combustion device 200 mentioned above corresponds to the amount of heat generated in the combustion device 200. Hereafter, the output of the combustion device 200 will simply be referred to as output.

[0112] Here, as valve control data 115, examples are shown of data for controlling flow control valves 45, 46, 75, and 76 so that the flow rate of hydrogen gas relative to the output and the flow rate of city gas relative to the output change while maintaining the set heat ratio.

[0113] Furthermore, as valve control data 115, data for controlling flow control valves 45, 46, 75, and 76 is stored so that the flow rate of the first fuel relative to the output and the flow rate of the second fuel relative to the output change linearly.

[0114] Here, a linear change in fuel flow rate with respect to power means that the relationship between power and fuel flow rate satisfies a linear function. In other words, a linear change in fuel flow rate with respect to power means that when the fuel flow rate is plotted against power, the trajectory of the fuel flow rate with respect to power is a straight line.

[0115] Furthermore, valve control data 115 is also stored, which includes data for controlling the valve opening of valves other than the flow control valves 45, 46, 75, and 76 (hereinafter referred to as "other valves") based on the types of the first and second fuels, the set heat ratio, the temperature of the combustion exhaust gas, and so on.

[0116] The valve control data 115 is set assuming that the pressure and temperature of the hydrogen gas directly downstream of the governor 47 in the hydrogen supply system 40 are under predetermined conditions. The valve control data 115 is set assuming that the pressure and temperature of the city gas directly downstream of the flow detector 77 in the city gas supply system 70 are under predetermined conditions. The predetermined conditions in the hydrogen supply system 40 may be the same as or different from the predetermined conditions in the city gas supply system 70.

[0117] Here, we will explain the valve control data 115 in detail.

[0118] Figure 3 shows an example of the intrinsic flow characteristics showing the relationship between valve opening and flow rate in the flow control valves 45, 46, 75, and 76 provided in the fuel supply device 30 for co-firing according to the embodiment. Note that each flow control valve has different intrinsic flow characteristics depending on the specifications of the flow control valve, etc.

[0119] Figure 4 shows an example of the opening characteristics of the flow control valves 45, 46, 75, and 76 provided in the fuel supply device 30 for co-firing according to the embodiment, showing the relationship between the command valve opening and the control valve opening. The opening characteristics shown in Figure 4 are an example of the opening characteristics of one flow control valve. Note that each flow control valve has different opening characteristics depending on the specifications of the flow control valve, etc.

[0120] Figure 5 shows an example of the relationship between the output of the fuel supply device 30 for co-firing according to the embodiment and the flow rates of each fuel. Note that Figure 5 shows the relationship at a predetermined set heat ratio.

[0121] As shown in Figure 3, the flow rate in a flow control valve does not change linearly with respect to the valve opening but rather curvedly. Here, we show an example of intrinsic flow rate characteristic 1, in which the flow rate characteristic with respect to the valve opening is convex downwards, and an example of intrinsic flow rate characteristic 2, in which the flow rate characteristic with respect to the valve opening is convex upwards.

[0122] Intrinsic flow rate characteristic 1 shows that the change in flow rate is small when the valve opening is small, and the change in flow rate becomes larger as the valve opening increases. Intrinsic flow rate characteristic 2 shows that the change in flow rate is large when the valve opening is small, and the change in flow rate becomes smaller as the valve opening increases.

[0123] Now, let's explain Figure 4.

[0124] The command valve opening on the horizontal axis in Figure 4 corresponds to the valve opening on the horizontal axis in Figure 3, and is the valve opening for a flow rate determined based on the intrinsic flow rate characteristics of the flow control valve. For example, in a flow control valve with intrinsic flow rate characteristic 1 in Figure 3, the valve opening is set to 50% for a requested flow rate F1. Also, in a flow control valve with intrinsic flow rate characteristic 2 in Figure 3, the valve opening is set to 50% for a requested flow rate F2. These valve openings correspond to the command valve opening in Figure 4.

[0125] The valve opening on the vertical axis of Figure 4 represents the valve opening used to correct the flow characteristics, which change curvilinearly with respect to the valve opening as shown in Figure 3, to flow characteristics that change linearly. As shown in Figure 4, a single flow control valve has multiple corrective valve opening patterns for linearizing the flow characteristics with respect to the command valve opening. In other words, the relationship between the command valve opening and the control valve opening for linearizing the flow characteristics is the opening characteristic. Figure 4 shows examples of 10 opening characteristics, from opening characteristic A to opening characteristic J. Note that the opening characteristics are not limited to 10 types.

[0126] In the example shown in Figure 4, for instance, if the command valve opening is 50%, there are 10 different modified valve opening patterns for linearizing the flow rate characteristics. For example, if the command valve opening is 50%, applying the modification in opening characteristic A adjusts the valve opening to a controlled valve opening of 92%. In this case, adjusting the valve opening to the controlled valve opening results in a flow rate greater than that at the command valve opening. Alternatively, for example, if the command valve opening is 50%, applying the modification in opening characteristic J adjusts the valve opening to a controlled valve opening of 8%. In this case, adjusting the valve opening to the controlled valve opening results in a flow rate less than that at the command valve opening.

[0127] Here, for a flow control valve having a downward-convex intrinsic flow rate characteristic 1 as shown in Figure 3, applying a modification in the opening degree characteristic C as shown in Figure 4, for example, results in a flow rate greater than the flow rate at the command valve opening. In this way, by applying a modification in the upward-convex opening degree characteristic C to the downward-convex intrinsic flow rate characteristic 1, the flow rate characteristic can be linearized, as shown by the dashed line in Figure 3. Note that linearizing the flow rate characteristic means changing the fuel flow rate linearly with respect to the output, as mentioned above.

[0128] For example, for a flow control valve having an upward-convex intrinsic flow rate characteristic 2 as shown in Figure 3, applying a modification in the opening degree characteristic G as shown in Figure 4 will result in a flow rate lower than the flow rate at the command valve opening. In this way, by applying a modification in the downward-convex opening degree characteristic G to the upward-convex intrinsic flow rate characteristic 2, the flow rate characteristic can be linearized, as shown by the dashed line in Figure 3.

[0129] The valve control data 115 stores data for controlling the flow control valves 45, 46, 75, and 76 in the hydrogen supply system 40, and the flow control valves 75 and 76 in the city gas supply system 70, based on the intrinsic flow characteristics and opening characteristics as described above, so that, for example, the flow rate of hydrogen gas relative to the output and the flow rate of city gas relative to the output change linearly while maintaining the set heat ratio.

[0130] Data for controlling flow control valves 45, 46, 75, and 76 is stored, for example, control data to set the valve opening of flow control valves 45, 46, 75, and 76 to the control valve opening, corresponding to the output.

[0131] Here, by controlling the flow control valves 45, 46, 75, and 76 based on the control data stored as valve control data 115, it is possible to linearly change the flow rate of hydrogen gas relative to the output and the flow rate of city gas relative to the output while maintaining the set heat ratio, for example, as shown in Figure 5.

[0132] Here, the data stored in the valve control data 115 for controlling the flow control valves 45, 46, 75, and 76 differs depending on the type of fuel, the set heat ratio, the intrinsic flow characteristics of each flow control valve, and the opening characteristics of each flow control valve. Therefore, the valve control data 115 contains multiple data sets for each combination of fuel type, set heat ratio, and flow control valve type.

[0133] Therefore, by setting the type of fuel supplied to the combustion device 200 (in this case, hydrogen gas and city gas), the set heat ratio for each fuel, and the type of flow control valve, the corresponding data is selected from the pre-set valve control data 115. In other words, by setting the type of fuel supplied to the combustion device 200 (in this case, hydrogen gas and city gas), the set heat ratio for each fuel, and the type of flow control valve, pre-set control data can be obtained for the flow control valves 45, 46, 75, and 76, which allow the flow rate of hydrogen gas and the flow rate of city gas to change linearly while maintaining the set heat ratio.

[0134] Here, the data stored in the valve control data 115 is based on data obtained by pre-acquiring the valve opening of each flow control valve so that the flow rate of hydrogen gas and the flow rate of city gas relative to the output can be changed linearly while maintaining the set heat ratio, based on the intrinsic flow rate characteristics and opening characteristics of the flow control valves 45 and 46 in the hydrogen supply system 40 and the flow control valves 75 and 76 in the city gas supply system 70, for all combinations of fuel type, set heat ratio, and valve type.

[0135] The fuel type, set calorific value ratio, and valve type that are pre-set to constitute the valve control data 115 are set, for example, based on the fuel type, set calorific value ratio, and valve type that are expected to be used.

[0136] Here, the memory unit 110 may also store various programs and data for operating the co-firing fuel supply device 30, in addition to the data described above.

[0137] The calculation unit 120 performs various calculation and determination processes using, for example, programs and data stored in the storage unit 110. The calculation unit 120 includes a valve control data selection unit 121, a temperature determination unit 122, a heat ratio determination unit 123, and a valve control unit 124.

[0138] The valve control data selection unit 121 selects corresponding data from the valve control data 115 based on the types of the first and second fuels, the set heat ratio, and the types of flow control valves 45, 46, 75, and 76. For example, the valve control data selection unit 121 obtains information on the types of the first and second fuels (hydrogen gas and city gas) by referring to the fuel type input data 111. The valve control data selection unit 121 also obtains information on the set heat ratio for each fuel by referring to the heat ratio input data 112. The valve control data selection unit 121 obtains information on each flow control valve by referring to the valve type input data 113. Then, based on this obtained information, the valve control data selection unit 121 selects data from the preset valve control data 115 that satisfies all of this information. The valve control data selection unit 121 outputs information related to the selected data to the valve control unit 124.

[0139] Furthermore, the valve control data selection unit 121 selects data from the valve control data 115 to control the valve opening of other valves, etc., based on the types of the first and second fuels, the set heat ratio, the temperature of the combustion exhaust gas, etc.

[0140] The temperature determination unit 122 determines whether the temperature of the combustion exhaust gas discharged from the combustion chamber 210 of the combustion device 200 is a preset temperature, based on the detection signal from the temperature sensor 240 and the set temperature stored in the combustion exhaust gas temperature data 114. Specifically, the temperature determination unit 122 determines whether the temperature of the combustion exhaust gas is lower than the set temperature, whether the temperature of the combustion exhaust gas is higher than the set temperature, and so on.

[0141] The heat ratio determination unit 123 determines whether the heat ratio of each fuel is equal to the set heat ratio for that fuel, based on the set heat ratio, detection signals from the flow detector 48 and flow detector 77. Specifically, the heat ratio determination unit 123 determines, for example, whether the heat ratio of hydrogen gas is below the set heat ratio for hydrogen gas, or whether the heat ratio of hydrogen gas exceeds the set heat ratio for hydrogen gas. Alternatively, the heat ratio determination unit 123 determines, for example, whether the heat ratio of city gas is below the set heat ratio for city gas, or whether the heat ratio of city gas exceeds the set heat ratio for city gas. The heat ratio determination unit 123 calculates the heat ratio of each fuel generated in the combustion device 200 based on the fuel characteristic data of the fuel type input data 111, detection signals from the flow detector 48 and flow detector 77.

[0142] Here, the heat ratio determination unit 123 calculates the heat ratio of each fuel, for example, based on the flow rate of each fuel.

[0143] The valve control unit 124 controls, for example, the flow control valve 45, flow control valve 46, flow control valve 75, flow control valve 76, and other valves in order to start or stop combustion in the combustion device 200, or to cause combustion in the combustion device 200 under predetermined conditions, based on data selected from the valve control data 115 by the valve control data selection unit 121.

[0144] For example, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is not at the set temperature, the valve control unit 124 performs control to adjust the flow rate of hydrogen gas and city gas in order to adjust the output corresponding to the heat output in the combustion device 200. That is, the valve control unit 124 adjusts the flow rate of the fuel to be burned in the combustion chamber 210 in order to adjust the temperature of the combustion exhaust gas. The equivalent ratio, which is calculated based on the fuel flow rate and oxidizer flow rate supplied to the combustion chamber 210, is kept constant when adjusting the output. The equivalent ratio is calculated by dividing the fuel-air ratio by the stoichiometric fuel-air ratio.

[0145] Specifically, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is lower than the set temperature, the valve control unit 124 outputs control signals to the flow rate control valves 45, 46, 75, and 76 via the output unit 130 to increase the flow rates of hydrogen gas and city gas, based on the valve control data 115. At this time, the oxidizer supply device 10 for co-firing controls the flow rate of the oxidizer to increase in accordance with the increased fuel flow rate in order to maintain a constant equivalent ratio. This control to increase the flow rate of the oxidizer may be performed by the valve control unit 124.

[0146] Furthermore, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is higher than the set temperature, the valve control unit 124 outputs control signals to the flow rate control valves 45, 46, 75, and 76 via the output unit 130 to reduce the flow rates of hydrogen gas and city gas, based on the valve control data 115. At this time, the oxidizer supply device 10 for co-firing controls the flow rate of the oxidizer to be reduced in accordance with the reduced fuel flow rate in order to maintain a constant equivalent ratio. This control to reduce the flow rate of the oxidizer may also be performed by the valve control unit 124.

[0147] Furthermore, if the heat ratio determination unit 123 determines that the heat ratio of each fuel is not the set heat ratio of each fuel, the valve control unit 124 performs control to adjust the flow rate ratio of each fuel supplied to the combustion device 200 in order to bring the heat ratio of each fuel to the set heat ratio of each fuel. The valve control unit 124 adjusts the flow rate ratio of each fuel by adjusting the valve opening of the heat ratio adjustment valve 43 or the heat ratio adjustment valve 73.

[0148] As mentioned above, the data for the fuel flow rate ratio of each fuel corresponding to the set heat ratio of each fuel is stored in the heat ratio input data 112. Based on this data, for example, the set flow rate of each fuel that satisfies the set heat ratio and fuel flow rate ratio of each fuel can be obtained.

[0149] For example, if the heat ratio determination unit 123 determines that the heat ratio in hydrogen gas is below the set heat ratio for hydrogen gas, the valve control unit 124 outputs a control signal to the heat ratio adjustment valve 43 via the output unit 130 to increase, for example, the flow rate ratio of hydrogen gas to city gas, based on the heat ratio input data 112.

[0150] For example, if the heat ratio determination unit 123 determines that the heat ratio in hydrogen gas exceeds the set heat ratio for hydrogen gas, the valve control unit 124 outputs a control signal to the heat ratio adjustment valve 43 via the output unit 130 to reduce, for example, the flow rate ratio of hydrogen gas to city gas, based on the heat ratio input data 112.

[0151] Furthermore, by adjusting the heat ratio in hydrogen gas to the set heat ratio for hydrogen gas, the heat ratio in city gas will also become the set heat ratio for city gas. Here, an example of adjusting the heat ratio in hydrogen gas to the set heat ratio for hydrogen gas is shown, but the heat ratio adjustment valve 73 may also be controlled to adjust the heat ratio in city gas to the set heat ratio for city gas. That is, the valve control unit 124 may output a control signal to the heat ratio adjustment valve 73 via the output unit 130 to increase or decrease the flow rate ratio of city gas to hydrogen gas, for example, based on the heat ratio input data 112.

[0152] The output unit 130 outputs, for example, control signals from the valve control unit 124 to the flow control valves 45, 46, 75, 76, the heat ratio adjustment valves 43, 73, etc.

[0153] Here, the processing performed by the control device 90 described above is implemented, for example, by a computer device.

[0154] (Overall operation of combustion device system 1) Next, an overview of the overall operation of the combustion device system 1 will be explained with reference to Figure 1. This explanation will focus on the case where a pilot burner 250 is included. The operation of the co-firing fuel supply device 30 will be explained in detail later.

[0155] When the combustion device system 1 starts up, the oxidizer supply source 13 and the blower 261 are driven.

[0156] Hydrogen gas is supplied from a hydrogen source 49 to a pilot mixed fuel supply pipe 58 via a pilot fuel supply pipe 55. City gas is supplied from a city gas source 78 to a pilot mixed fuel supply pipe 58 via a pilot fuel supply pipe 80. The mixed fuel of hydrogen gas and city gas is then supplied from the pilot mixed fuel supply pipe 58 to the pilot burner 250.

[0157] In addition, air is supplied from the oxidizer supply source 13 to the pilot burner 250 via the pilot oxidizer supply pipe 12.

[0158] The premixed fuel-air mixture ejected from the pilot burner 250 is then ignited by an ignition device (not shown) to form a pilot flame.

[0159] Next, according to a predetermined set heat ratio, hydrogen gas is supplied from the hydrogen supply source 49 to the first fuel injection unit 220 via the main fuel supply pipe 41 and the bypass fuel supply pipe 42, and city gas is supplied from the city gas supply system 70 to the second fuel injection unit 221 via the main fuel supply pipe 71 and the bypass fuel supply pipe 72.

[0160] In addition, air is supplied from the oxidant supply source 13 to the oxidant ejection section 230 via the oxidant supply pipe 11 for the main burner.

[0161] The fuel gas injected into the combustion chamber 210 from the first fuel injection section 220 and the second fuel injection section 221 mixes with the oxidizer injected from the oxidizer injection section 230 to form a fuel mixture. This mixture is ignited by the pilot flame to form the main flame.

[0162] Furthermore, after combustion in the main burner 235 has started, the supply of fuel and air to the pilot burner 250 may be shut off.

[0163] Here, when the fuel supply to the pilot burner 250 is shut off, for example, nitrogen gas is supplied from the nitrogen gas supply source 61 to the pilot mixed fuel supply pipe 58 via the pilot burner purge gas supply pipe 63 while reducing the fuel flow rate. This prevents the flame from flashing back into the pilot burner 250.

[0164] When combustion begins in the combustion chamber 210, the blower 261 draws the combustion gases from the combustion chamber 210 into the combustion gas exhaust pipe 260. In addition, a portion of the combustion exhaust gas that has been introduced and used in the combustion gas utilization section 290 is returned to the combustion chamber 210 via the return pipe 271. At this time, a predetermined amount of air is introduced into the return pipe 271 via the atmospheric intake pipe 272 and is guided into the combustion chamber 210 together with the combustion exhaust gas. This combustion exhaust gas, including the air, is also drawn into the combustion gas exhaust pipe 260 together with the combustion gas generated by combustion.

[0165] Here, the combustion exhaust gas in the combustion chamber 210 is drawn in by the blower 261, so the pressure in the combustion chamber 210 becomes lower than the pressure in the combustion gas utilization space of the combustion gas utilization section 290. Therefore, the combustion exhaust gas in the combustion gas utilization space is guided back to the combustion chamber 210 through the return pipe 271.

[0166] The combustion exhaust gas drawn into the combustion gas exhaust pipe 260 is then guided to the combustion gas utilization section 290.

[0167] Here, when the fuel supply to the main burner 235 is shut off, for example, nitrogen gas is supplied from the nitrogen gas supply source 61 to the main fuel supply pipe 41 and the bypass fuel supply pipe 42 via the main burner purge gas supply pipe 62 while reducing the fuel flow rate. This prevents the flame from flashing into the first fuel injection section 220 of the main burner 235.

[0168] (Operation of the fuel supply device 30 for co-firing) Next, we will explain the operation of the fuel supply device 30 for co-firing.

[0169] Figure 6 is a flowchart illustrating the fuel supply method of the co-firing fuel supply device 30 according to the embodiment.

[0170] As shown in Figure 6, the storage unit 110 of the control device 90 sets and stores information regarding each fuel type (fuel type) from the external input means input by the input unit 100 as fuel type input data 111 (step S10).

[0171] The memory unit 110 stores information regarding the set heat ratio of each fuel from the external input means input by the input unit 100 as heat ratio input data 112 (step S11).

[0172] The memory unit 110 sets and stores information regarding the valve type of each flow control valve received from the external input means by the input unit 100 as valve type input data 113 (step S12).

[0173] The memory unit 110 stores information regarding the set temperature of the combustion exhaust gas at the outlet of the combustion chamber 210, which has been input by the input unit 100 from the external input means, as combustion exhaust gas temperature data 114 (step S13).

[0174] Here, the processes in steps S10-S13 are not limited to being performed in the order described above; it is sufficient if the processes in steps S10-S13 are executed.

[0175] Next, the valve control data selection unit 121 selects data from the pre-set valve control data 115 that satisfies all of the information set in steps S10 to S13, based on the information set in steps S10 to S13 (step S14). The valve control data selection unit 121 also selects data from the valve control data 115 to control other valves, based on the information set in steps S10 to S13. Finally, the valve control data selection unit 121 outputs information related to the selected data to the valve control unit 124.

[0176] The process in step S14 enables combustion in the main burner 235 and the pilot burner 250. After the process in step S14, as described above, combustion starts in the pilot burner 250 and the main burner 235, and the combustion device system 1 becomes operational (step S15).

[0177] After combustion begins, the temperature determination unit 122 determines whether the temperature of the combustion exhaust gas is higher than the set temperature based on the detection signal from the temperature detector 240 and the set temperature stored in the combustion exhaust gas temperature data 114 (step S16).

[0178] In step S16, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is higher than the set temperature (Yes in step S16), the valve control unit 124 performs adjustments to bring the temperature of the combustion exhaust gas to the set temperature (step S17). Specifically, based on the valve control data 115, the valve control unit 124 outputs control signals to the flow control valves 45, 46, 75 and 76 via the output unit 130 to reduce the flow rate of hydrogen gas and city gas while maintaining the set calorific value ratio for each fuel. Then, the flow control valves 45, 46, 75 and 76 adjust their valve openings based on the control signals.

[0179] As a result, the amount of heat generated by combustion decreases by reducing the flow rates of hydrogen gas and city gas, and therefore the temperature of the combustion exhaust gas introduced into the combustion gas exhaust pipe 260 decreases. In this case, the oxidizer supply device 10 for co-firing is controlled to reduce the flow rate of the oxidizer in accordance with the reduced fuel flow rate in order to maintain a constant equivalent ratio.

[0180] Then, after the processing in step S17, the processing from step S16 is repeated.

[0181] If the determination in step S16 determines that the temperature of the combustion exhaust gas is not higher than the set temperature, in other words, that the temperature of the combustion exhaust gas does not exceed the set temperature (No. in step S16), the temperature determination unit 122 determines whether the temperature of the combustion exhaust gas is lower than the set temperature based on the detection signal from the temperature detector 240 and the set temperature stored in the combustion exhaust gas temperature data 114 (step S18).

[0182] In step S18, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is lower than the set temperature (Yes in step S18), the valve control unit 124 performs adjustments to bring the temperature of the combustion exhaust gas to the set temperature (step S19). Specifically, based on the valve control data 115, the valve control unit 124 outputs control signals to the flow control valves 45, 46, 75 and 76 via the output unit 130 to increase the flow rate of hydrogen gas and city gas while maintaining the set calorific value ratio for each fuel. Then, the flow control valves 45, 46, 75 and 76 adjust their valve openings based on the control signals.

[0183] As a result, increasing the flow rates of hydrogen gas and city gas increases the amount of heat generated by combustion, causing the temperature of the combustion exhaust gas introduced into the combustion gas exhaust pipe 260 to rise. In this case, the oxidizer supply device 10 for co-firing is controlled to increase the flow rate of the oxidizer in accordance with the increased fuel flow rate in order to maintain a constant equivalent ratio.

[0184] Then, after the processing in step S19, the processing from step S16 is repeated.

[0185] In step S18, if the temperature determination unit 122 determines that the temperature of the combustion exhaust gas is not lower than the set temperature (No. in step S18), the valve control unit 124 determines whether or not information to stop the operation of the combustion device system 1 has been input (step S20). The information to stop the operation is input, for example, by an external input means. The information to stop the operation is input by the input unit 100.

[0186] If the determination in step S20 determines that no information has been entered to stop the operation of the combustion device system 1 (No. in step S20), the co-firing fuel supply device 30 will execute the process from step S10. Note that if the combustion device system 1 is in operation, the process from step S15 will not be executed.

[0187] If the determination in step S20 determines that information to stop the operation of the combustion device system 1 has been input (Yes in step S20), the valve control unit 124 outputs a control signal to stop the operation of the combustion device system 1 to each flow control valve and other valves in the combustion device system 1 via the output unit 130 (step S21). As a result of the process in step S21, the combustion device system 1 is stopped and the above-described series of processes are completed.

[0188] Furthermore, in the operation of the co-firing fuel supply device 30, after the processing in step S15 described above (after combustion has started), processing related to the heat ratio is performed along with the processing related to the temperature of the combustion exhaust gas described above.

[0189] Figure 7 is a flowchart illustrating the process related to the heat ratio in the fuel supply method of the fuel supply device 30 for co-firing according to the embodiment. Here, we show an example in which, in the process related to the heat ratio, the heat ratio of hydrogen gas is adjusted to the set heat ratio for hydrogen gas, and as a result, the heat ratio of city gas is also adjusted to the set heat ratio for city gas.

[0190] As shown in Figure 7, the heat ratio determination unit 123 receives detection signals from the flow rate detector 48 and the flow rate detector 77 via the input unit 100 (step S30).

[0191] The heat ratio determination unit 123 calculates the heat ratio of each fuel generated in the combustion device 200 based on the fuel type input data 111, the flow rate detector 48, and the detection signals from the flow rate detector 77 (step S31). At this time, the heat ratio determination unit 123 obtains information such as the type of fuel being used and fuel characteristics based on the fuel type input data 111.

[0192] Next, the heat ratio determination unit 123 determines whether the heat ratio of hydrogen gas exceeds the set heat ratio for hydrogen gas based on the heat ratio of each fuel calculated in step S31 and the heat ratio input data 112 (step S32).

[0193] In step S32, if the heat ratio determination unit 123 determines that the heat ratio of hydrogen gas exceeds the set heat ratio for hydrogen gas (Yes in step S32), the valve control unit 124 outputs a control signal to the heat ratio adjustment valve 43 via the output unit 130 to reduce the flow rate ratio of hydrogen gas to city gas, based on the heat ratio input data 112 (step S33). The heat ratio adjustment valve 43 then adjusts its valve opening based on the control signal. By adjusting the heat ratio of hydrogen gas to the set heat ratio for hydrogen gas, the heat ratio of city gas also becomes the set heat ratio for city gas.

[0194] Then, after the processing in step S33, the processing from step S30 is repeated.

[0195] If the determination in step S32 determines that the heat ratio of hydrogen gas does not exceed the set heat ratio for hydrogen gas (No. in step S32), the heat ratio determination unit 123 determines whether the heat ratio of hydrogen gas is below the set heat ratio for hydrogen gas (step S34).

[0196] In step S34, if the heat ratio determination unit 123 determines that the heat ratio of hydrogen gas is below the set heat ratio for hydrogen gas (Yes in step S34), the valve control unit 124 outputs a control signal to the heat ratio adjustment valve 43 via the output unit 130 to increase the flow rate ratio of hydrogen gas to city gas, based on the heat ratio input data 112 (step S35). The heat ratio adjustment valve 43 then adjusts its valve opening based on the control signal. By adjusting the heat ratio of hydrogen gas to the set heat ratio for hydrogen gas, the heat ratio of city gas also becomes the set heat ratio for city gas.

[0197] Then, after the processing in step S35, the processing from step S30 is repeated.

[0198] If, in step S34, the heat ratio determination unit 123 determines that the heat ratio of hydrogen gas is not below the set heat ratio for hydrogen gas (No. in step S34), the processing related to the heat ratio is terminated. In this case, the co-firing fuel supply device 30 may repeat the processing from step S30.

[0199] In the process related to the heat ratio described above, the heat ratio of each fuel is adjusted to the set heat ratio for each fuel. At this time, the flow rate of the fuel may increase or decrease due to the adjustment of the heat ratio of each fuel. This increase or decrease in the flow rate of the fuel may change the temperature of the combustion exhaust gas discharged from the combustion chamber 210, but the temperature of the combustion exhaust gas is adjusted to the set temperature by the process from step S16, which is the process related to the temperature of the combustion exhaust gas shown in Figure 6 above.

[0200] Here, we have shown an example in which, in the process of processing the heat ratio, the heat ratio of hydrogen gas is adjusted to the set heat ratio for hydrogen gas, and as a result, the heat ratio of city gas is also adjusted to the set heat ratio for city gas. However, in the process of processing the heat ratio shown in Figure 7, the heat ratio of city gas may also be adjusted to the set heat ratio for city gas. That is, by adjusting the heat ratio of city gas to the set heat ratio for city gas, the heat ratio of hydrogen gas may also be adjusted to the set heat ratio for hydrogen gas as a result.

[0201] As described above, the fuel supply device 30 for co-firing according to the embodiment includes valve control data 115 that stores data for controlling the flow control valves 45, 46, 75, and 76 so that the flow rate of hydrogen gas relative to the output and the flow rate of city gas relative to the output change while maintaining a set heat ratio, by adjusting the flow characteristics of the flow control valves 45 and 46 in the hydrogen supply system 40 and the flow characteristics of the flow control valves 75 and 76 in the city gas supply system 70.

[0202] Furthermore, valve control data 115 stores data for controlling flow control valves 45, 46, 75, and 76 so that the hydrogen gas flow rate and the city gas flow rate relative to the output change linearly.

[0203] The valve control data 115 stores data for controlling each flow control valve so that the flow rate of each fuel relative to the output changes linearly while maintaining the set heat ratio, for all combinations of fuel type, set heat ratio, and flow control valve type.

[0204] Furthermore, by controlling the flow control valves 45, 46, 75, and 76 based on the valve control data 115, the flow rate of hydrogen gas and the flow rate of city gas relative to the output can be changed linearly while maintaining the set calorific value ratio. This makes it possible to easily change the flow rate of hydrogen gas and city gas according to the output while maintaining the set calorific value ratio for each fuel at a predetermined ratio.

[0205] Furthermore, by setting the type of fuel supplied to the combustion device 200, the set heat ratio for each fuel, and the type of flow control valve, and selecting the corresponding data from the pre-set valve control data 115, control information for each flow control valve 45, 46, 75, and 76 can be obtained to linearly change the flow rate of hydrogen gas and the flow rate of city gas relative to the output while maintaining the set heat ratio.

[0206] By controlling both the flow control valve 45 and the flow control valve 46 in the hydrogen supply system 40, and both the flow control valve 75 and the flow control valve 76 in the city gas supply system 70, regardless of the flow rate, and thereby adjusting the fuel flow rate, a relationship between output and fuel flow rate that changes along a predetermined straight line can be obtained. That is, except when either fuel is shut off, the valve openings of the flow control valves 45 and 46, and the valve openings of the flow control valves 75 and 76 are always controlled to adjust the fuel flow rate.

[0207] Furthermore, the fuel supply device 30 for co-firing can maintain the temperature of the combustion exhaust gas, as shown in Figure 6, and the calorific ratio, as shown in Figure 7, by performing both the temperature of the combustion exhaust gas and the calorific ratio of each fuel, while maintaining the calorific ratio of each fuel at the set calorific ratio for each fuel.

[0208] Furthermore, the valve control data 115 stores data for controlling each flow control valve for all combinations of fuel type, set heat ratio, and flow control valve type. Therefore, even when operating with different combinations of fuel type, set heat ratio, and flow control valve type, it is possible to easily adjust the fuel flow rate while maintaining the above-mentioned effects and maintaining the heat ratio for each fuel at the set heat ratio for each fuel.

[0209] (Other embodiments) In the combustion device system 1 described above, a configuration utilizing exhaust gas recirculation (EGR) may be adopted, in which a portion of the combustion gas generated in the combustion chamber 210 is mixed with the oxidizer.

[0210] For example, an EGR (exhaust gas recirculation) pipe (not shown) is provided to introduce a portion of the combustion gas in the combustion chamber 210 into the main burner oxidizer supply pipe 11. When exhaust gas recirculation (EGR) is used, in Figure 1, one end of the EGR pipe is open into the combustion chamber 210, and the other end of the EGR pipe is connected to the main burner oxidizer supply pipe 11. The other end of the EGR pipe is connected to the main burner oxidizer supply pipe 11 between the flow control valve 14 and the main burner 235.

[0211] The EGR piping is equipped with a blower for extracting combustion gases from inside the combustion chamber 210 to the main burner oxidizer supply pipe 11, and a flow control valve for adjusting the flow rate of combustion gases introduced into the main burner oxidizer supply pipe 11.

[0212] Furthermore, exhaust gas recirculation (EGR) is preferably used, for example, when air is used as the oxidizer during the operation of the combustion device system 1 and the set heat ratio of hydrogen gas is high. By using exhaust gas recirculation (EGR) under these combustion conditions, NOx generated by combustion can be suppressed and the NOx concentration in the combustion gas can be reduced.

[0213] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0214] 1... Combustion system, 10... Oxidizer supply device for co-firing, 11... Oxidizer supply pipe for main burner, 12... Oxidizer supply pipe for pilot, 13... Oxidizer supply source, 14, 15, 16, 45, 46, 57, 65, 67, 75, 76, 82... Flow control valve, 30... Fuel supply device for co-firing, 40... Hydrogen supply system, 41... Main fuel supply pipe, 42... Bypass fuel supply pipe, 43, 73... Valve for adjusting heat ratio, 44, 56, 6 4, 66, 74, 81...Shut-off valve, 47...Governor, 48...Flow sensor, 49...Hydrogen supply source, 55, 80...Pilot fuel supply pipe, 58...Pilot mixed fuel supply pipe, 60...Purge gas supply pipe, 61...Purge gas supply source, 62...Main burner purge gas supply pipe, 63...Pilot burner purge gas supply pipe, 70...City gas supply system, 71...Main fuel supply pipe, 72...Bypass fuel supply pipe, 7 7...Flow detector, 78...City gas supply source, 90...Control device, 100...Input unit, 110...Storage unit, 111...Fuel type input data, 112...Heat ratio input data, 113...Valve type input data, 114...Combustion exhaust gas temperature data, 115...Valve control data, 120...Calculation unit, 121...Valve control data selection unit, 122...Temperature determination unit, 123...Heat ratio determination unit, 124...Valve control unit, 130...Output unit, 200...Combustion C1, C2, C3, C4... Combustion equipment, 210... Combustion chamber, 220... First fuel injection unit, 221... Second fuel injection unit, 230... Oxidizer injection unit, 235... Main burner, 240... Temperature sensor, 250... Pilot burner, 260... Combustion gas exhaust pipe, 261... Blower, 270... Combustion exhaust gas return system, 271... Return piping, 272... Atmospheric intake pipe, 273... Flow rate adjustment unit, 290... Combustion gas utilization unit, C1, C2, C3, C4... Connecting units.

Claims

1. A fuel supply device for co-firing that supplies fuel to a combustion device capable of co-firing multiple fuels, A first fuel supply system that supplies the first fuel, A second fuel supply system that supplies a second fuel, A control device for adjusting the flow rates of the first fuel and the second fuel, Equipped with, The first fuel supply system is, A first main fuel supply pipe equipped with a first flow control valve for adjusting the flow rate of the first fuel, A second flow control valve for adjusting the flow rate of the first fuel is provided, and a first bypass fuel supply pipe is connected to the first main fuel supply pipe, bypassing the first flow control valve. A first heat ratio adjustment valve is provided in the first main fuel supply pipe between the combustion device and the first bypass fuel supply pipe, specifically in the connection between the first bypass fuel supply pipe and the first main fuel supply pipe, and the first heat ratio adjustment valve is provided in the first main fuel supply pipe between the first connection on the combustion device side and the combustion device, and the valve opening is set based on a set heat ratio indicating the ratio of the calorific values ​​of each fuel in the combustion device, which is set in advance. Equipped with, The second fuel supply system described above is: A second main fuel supply pipe equipped with a third flow control valve for adjusting the flow rate of the second fuel, A second bypass fuel supply pipe is provided, which is connected to the second main fuel supply pipe by bypassing the third flow control valve, and which includes a fourth flow control valve for adjusting the flow rate of the second fuel, A second heat ratio adjustment valve is provided in the second main fuel supply pipe between the combustion device and the second connection portion on the combustion device side of the connection portion between the second bypass fuel supply pipe and the second main fuel supply pipe, and the valve opening is set based on the set heat ratio. Equipped with, The control device is Valve control data for controlling the first, second, third, and fourth flow control valves, set based on the types of the first and second fuels, the set heat ratio, the intrinsic flow characteristics showing the relationship between valve opening and flow rate in the first, second, third, and fourth flow control valves, and the opening characteristics showing the relationship between command valve opening and control valve opening in the first, second, third, and fourth flow control valves, such that the flow rate of the first fuel and the flow rate of the second fuel relative to the output corresponding to the heat output in the combustion device change while maintaining the set heat ratio, A valve control data selection unit selects corresponding data from the valve control data based on the types of the first and second fuels, the set heat ratio, and the types of the first, second, third, and fourth flow control valves. A temperature determination unit that determines whether the temperature of the combustion exhaust gas discharged from the combustion device is a preset temperature, If the temperature determination unit determines that the temperature of the combustion exhaust gas is not the set temperature, the valve control unit controls the first flow control valve, the second flow control valve, the third flow control valve, and the fourth flow control valve based on the data selected by the valve control data selection unit to adjust the temperature of the combustion exhaust gas to the set temperature. A fuel supply device for co-firing, characterized by comprising the following:

2. The fuel supply device for co-firing according to claim 1, characterized in that the flow rate of the first fuel with respect to the output and the flow rate of the second fuel with respect to the output change linearly.

3. The fuel supply device for co-firing further includes a heat ratio determination unit that determines whether the heat ratio of each fuel is the set heat ratio based on the set heat ratio, the flow rate of the first fuel supplied to the combustion device, and the flow rate of the second fuel. The fuel supply device for co-firing according to claim 1 or 2, characterized in that, if the heat ratio determination unit determines that the heat ratio of each fuel is not the set heat ratio, the valve control unit controls the first heat ratio adjustment valve or the second heat ratio adjustment valve to adjust the heat ratio of each fuel to the set heat ratio for each fuel.

4. A fuel supply method for a fuel supply device for co-firing, which supplies fuel to a combustion device capable of co-firing multiple fuels, The aforementioned fuel supply device for co-firing is A first fuel supply system that supplies the first fuel, A second fuel supply system that supplies a second fuel, A control device for adjusting the flow rates of the first fuel and the second fuel, Equipped with, The first fuel supply system is, A first main fuel supply pipe equipped with a first flow control valve for adjusting the flow rate of the first fuel, A second flow control valve for adjusting the flow rate of the first fuel is provided, and a first bypass fuel supply pipe is connected to the first main fuel supply pipe, bypassing the first flow control valve. A first heat ratio adjustment valve is provided in the first main fuel supply pipe between the combustion device and the first bypass fuel supply pipe, specifically in the connection between the first bypass fuel supply pipe and the first main fuel supply pipe, and the first heat ratio adjustment valve is provided in the first main fuel supply pipe between the first connection on the combustion device side and the combustion device, and the valve opening is set based on a set heat ratio indicating the ratio of the calorific values ​​of each fuel in the combustion device, which is set in advance. Equipped with, The second fuel supply system described above is: A second main fuel supply pipe equipped with a third flow control valve for adjusting the flow rate of the second fuel, A second bypass fuel supply pipe is provided, which is connected to the second main fuel supply pipe by bypassing the third flow control valve, and which includes a fourth flow control valve for adjusting the flow rate of the second fuel, A second heat ratio adjustment valve is provided in the second main fuel supply pipe between the combustion device and the second connection portion on the combustion device side of the connection portion between the second bypass fuel supply pipe and the second main fuel supply pipe, and the valve opening is set based on the set heat ratio. Equipped with, The control device is set based on the types of the first and second fuels, the set heat ratio, the intrinsic flow characteristics showing the relationship between valve opening and flow rate in the first, second, third, and fourth flow control valves, and the opening characteristics showing the relationship between command valve opening and control valve opening in the first, second, third, and fourth flow control valves, and stores valve control data for controlling the first, second, third, and fourth flow control valves so that the flow rate of the first fuel and the flow rate of the second fuel relative to the output corresponding to the heat amount in the combustion device change while maintaining the set heat ratio. The control device selects corresponding data from the valve control data based on the types of the first and second fuels, the set heat ratio, and the types of the first, second, third, and fourth flow control valves. The control device determines whether the temperature of the combustion exhaust gas discharged from the combustion device is a preset temperature, A fuel supply method in a fuel supply device for co-firing, characterized in that, if the control device determines that the temperature of the combustion exhaust gas is not the set temperature, the control device controls the first flow control valve, the second flow control valve, the third flow control valve, and the fourth flow control valve based on data selected from the valve control data to adjust the temperature of the combustion exhaust gas to the set temperature.

5. The fuel supply method in a co-firing fuel supply device according to claim 4, characterized in that the flow rate of the first fuel and the flow rate of the second fuel change linearly with respect to the output.

6. The control device determines, based on the flow rate of the first fuel and the flow rate of the second fuel supplied to the combustion device, whether the heat ratio of each fuel is the set heat ratio. The fuel supply method in a co-firing fuel supply device according to claim 4 or 5, characterized in that, if the control device determines that the heat ratio of each fuel is not the set heat ratio, the control device controls the first heat ratio adjustment valve or the second heat ratio adjustment valve to adjust the heat ratio of each fuel to the set heat ratio for each fuel.

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