Diffusion combustion type dual fuel burner and method for controlling its flame length

Abstract

To provide a dual fuel burner of liquid fuel and hydrogen gas fuel capable of controlling a flame length.SOLUTION: Provided is a diffusion-combustion dual fuel burner, including: a liquid fuel nozzle for jetting liquid fuel at a liquid fuel jetting flow rate; a hydrogen gas fuel nozzle for jetting hydrogen gas fuel at a gas fuel jetting flow rate; a combustion supporting gas nozzle for supplying combustion supporting gas; a liquid fuel adjusting device for adjusting a gas fuel jet flow rate; a gas fuel adjusting device for adjusting a liquid fuel jet flow rate; a controller; and a flame length measuring instrument for measuring a flame length. The controller acquires the flame length measured by the flame length measuring instrument, and when the flame length is out of a given proper flame length range, corrects the present mixed combustion ratio of the liquid fuel and the hydrogen gas fuel to make the flame length to be within the proper flame length range, and causes the liquid fuel adjusting device and the gas fuel adjusting device to operate such that the liquid fuel and the hydrogen gas fuel combust at the corrected mixed combustion ratio.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a burner that uses a binary fuel of liquid fuel and hydrogen gas fuel and burns the fuel in a diffusion combustion method.

Background Art

[0002] Conventionally, the gas fuel of a combustion furnace has mainly been natural gas. However, due to the increasing interest in low environmental impact in recent years, hydrogen as a gas fuel that does not emit carbon dioxide during combustion has been attracting attention. For example, Patent Document 1 discloses a burner that uses a binary fuel of emulsion fuel oil and hydrogen gas and burns the fuel in a diffusion combustion method. The diffusion combustion method refers to a combustion method in which a gas fuel and a supporting combustion gas are separately supplied to a burner port, and the gas fuel and air are supplied by diffusion to a flame generated at the interface between the gas fuel and the air to maintain the flame.

[0003] The burner of Patent Document 1 has a coaxial triple tube structure in which emulsion fuel oil is injected from the center of an injection nozzle, oxygen gas is injected from around the fuel oil, and hydrogen gas is injected from around the oxygen gas. In this burner, since hydrogen gas and oxygen gas obtained by electrolyzing water are used, for 0.010 - 0.050 m 3 / h of emulsion fuel oil, 2 - 5 m of hydrogen gas 3 / h and half of the hydrogen gas amount of oxygen gas are supplied. Since hydrogen gas and oxygen gas burn efficiently to obtain high heat, the effect of completely burning the emulsion fuel oil is demonstrated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a dual-fuel burner using a diffusion combustion method that utilizes liquid fuel (i.e., fuel oil) and hydrogen gas fuel, it is presumed that the flame length fluctuates not only with respect to the fuel injection velocity but also with respect to the mixing ratio of the liquid fuel and hydrogen gas fuel. This is because the difference in combustion characteristics between the liquid fuel and hydrogen gas fuel changes the distribution of combustion-supporting gas to each fuel according to the mixing ratio, and the time it takes for the fuel to burn completely fluctuates, thus causing the flame length to fluctuate as well.

[0006] Dual-fuel burners using liquid fuel and hydrogen gas fuel can be installed in combustion furnaces such as boilers and incinerators. Some combustion furnaces have a predetermined flame length that depends on the size of the furnace. In such combustion furnaces, if the flame length of the flame produced by the burner exceeds the appropriate flame length, the flame may interfere with the furnace wall and damage the combustion furnace. In addition, some combustion furnaces require the flame length to be increased or decreased.

[0007] This disclosure is made in view of the above circumstances, and its purpose is to provide a dual fuel burner for liquid fuel and hydrogen gas fuel and a method for controlling its flame length, the burner being capable of controlling the flame length. [Means for solving the problem]

[0008] To solve the above problems, a diffusion combustion type dual fuel burner according to one aspect of this disclosure is provided. A liquid fuel nozzle that ejects liquid fuel at a liquid fuel injection flow rate, A hydrogen gas fuel nozzle is provided around the liquid fuel nozzle and ejects hydrogen gas fuel at a gas fuel injection flow rate, At least one combustion-supporting gas nozzle that supplies combustion-supporting gas to the liquid fuel ejected from the liquid fuel nozzle and to the hydrogen gas fuel ejected from the hydrogen gas fuel nozzle, Adjust the gas fuel injection flow rate. gas Fuel adjustment device, Adjust the liquid fuel injection flow rate. liquid Fuel adjustment device, A controller that controls the operation of the liquid fuel adjustment device and the gas fuel adjustment device, The system includes a flame length measuring instrument for measuring the flame length of the flame produced by the combustion of the liquid fuel and the hydrogen gas fuel, The controller is characterized by acquiring the flame length measured by the flame length measuring instrument, and if the flame length falls outside a given suitable flame length range, correcting the current co-combustion ratio of the liquid fuel and the hydrogen gas fuel so that the flame length falls within the suitable flame length range, and operating the liquid fuel adjustment device and the gas fuel adjustment device so that the liquid fuel and the hydrogen gas fuel are burned at the corrected co-combustion ratio.

[0009] Furthermore, a diffusion combustion type dual fuel burner according to another aspect of this disclosure is: A liquid fuel nozzle that ejects liquid fuel at a liquid fuel injection flow rate, A hydrogen gas fuel nozzle is provided around the liquid fuel nozzle and ejects hydrogen gas fuel at a gas fuel injection flow rate, A combustion-supporting gas nozzle supplies a combustion-supporting gas to the liquid fuel ejected from the liquid fuel nozzle and the hydrogen gas fuel ejected from the hydrogen gas fuel nozzle, Adjust the gas fuel injection flow rate. gas Fuel adjustment device, Adjust the liquid fuel injection flow rate. liquid Fuel adjustment device, The system includes a controller that controls the operation of the liquid fuel adjustment device and the gas fuel adjustment device, The controller is characterized by acquiring a target heat input value and a flame length command value, acquiring the relationship between the co-firing ratio of a given liquid fuel and hydrogen gas fuel and the flame length, using this relationship to determine the co-firing ratio corresponding to the flame length command value, determining the liquid fuel injection flow rate and the gas fuel injection flow rate based on the co-firing ratio and the target heat input value, operating the liquid fuel adjustment device so that the liquid fuel is injected at the liquid fuel injection flow rate, and operating the gas fuel adjustment device so that the hydrogen gas fuel is injected at the gas fuel injection flow rate.

[0010] Furthermore, a flame length control method for a diffusion combustion type dual fuel burner according to another aspect of the present disclosure is a flame length control method for a diffusion combustion type dual fuel burner that diffusely burns a dual fuel of liquid fuel and hydrogen gas fuel, To obtain the flame length of the flame produced by the combustion of the liquid fuel and the hydrogen gas fuel, To obtain a given flame length suitability range, and, If the flame length falls outside the appropriate flame length range, the current mixing ratio of the liquid fuel and the hydrogen gas fuel is modified so that the flame length falls within the appropriate flame length range, and The invention is characterized by comprising burning the liquid fuel and the hydrogen gas fuel at a modified co-combustion ratio.

[0011] Furthermore, a flame length control method for a diffusion combustion type dual fuel burner according to another aspect of the present disclosure is a flame length control method for a diffusion combustion type dual fuel burner that diffusely burns a dual fuel of liquid fuel and hydrogen gas fuel, To obtain the target heat input value and the commanded flame length value, To obtain the relationship between the co-firing ratio of a given liquid fuel and hydrogen gas fuel and the flame length, Using the aforementioned relationship, determine the co-combustion ratio corresponding to the flame length command value. The sum of the heat content of the ejected liquid fuel and the heat content of the ejected hydrogen gas fuel is taken as the heat input, and the liquid fuel injection flow rate and the gas fuel injection flow rate are determined based on the co-firing ratio and the target heat input value, and, The invention is characterized by including the ejection of the liquid fuel at the aforementioned liquid fuel ejection flow rate and the ejection of the hydrogen gas fuel at the aforementioned gas fuel ejection flow rate. [Effects of the Invention]

[0012] According to this disclosure, a dual fuel burner for liquid fuel and hydrogen gas fuel and a method for controlling its flame length can be provided, which allows for control of the flame length. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a cross-sectional view showing the schematic configuration of the burner. [Figure 2] Figure 2 is a view of the burner port of the burner shown in FIG. 1 as seen parallel to the burner axis. [Figure 3] Figure 3 is a block diagram showing the configuration of the control system of the burner. [Figure 4] Figure 4 is a chart showing an example of the relationship between the co-combustion ratio of hydrogen gas fuel and liquid fuel and the flame length. [Figure 5] Figure 5 is a schematic view of a combustion furnace according to Application Example 1 of the burner. [Figure 6] Figure 6 is a diagram showing the flow of the flame length control process of the burner according to Application Example 1. [Figure 7] Figure 7 is a schematic view of a combustion furnace according to Application Example 2 of the burner. [Figure 8] Figure 8 is a diagram showing the flow of the flame length control process of the burner according to Application Example 2. [Figure 9] Figure 9 is a diagram showing the flow of the flame length control process of the burner according to Application Example 2. [Figure 10] Figure 10 is a view of the burner port of the burner according to the modified example as seen parallel to the burner axis.

Mode for Carrying Out the Invention

[0014] Next, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the schematic configuration of a diffusion combustion type dual fuel burner (hereinafter simply referred to as "burner 10"), and FIG. 2 is a view of the burner port of burner? 10 as seen parallel to the burner axis X. As shown in FIGS. 1 and 2, the burner ?10 according to the present disclosure is a diffusion combustion type dual fuel burner that uses liquid fuel ?21 and hydrogen gas fuel ?22 as fuels. The burner ?10 may be capable of not only co-combusting the liquid fuel ?21 and the hydrogen gas fuel?22 but also solely burning the liquid fuel ?21 or the hydrogen gas fuel?22.

[0015] The burner 10 is positioned on the furnace wall of the combustion furnace 1 and is configured to inject fuel into the furnace of the combustion furnace 1 in a manner substantially parallel to the burner axis X. In this disclosure, the flame length L is defined as the distance parallel to the burner axis X from the liquid fuel outlet 61, which is the injection port for the liquid fuel 21, to the tip of the flame. However, the method of defining the flame length L is not limited to this, and the flame length may be defined by conventional methods.

[0016] The burner 10 comprises at least one liquid fuel nozzle 31, at least one hydrogen gas fuel nozzle 32, and at least one combustion-supporting gas nozzle 33. In this embodiment, the burner 10 has the liquid fuel nozzle 31 positioned in the center overlapping with the burner axis X, a first combustion-supporting gas nozzle 33a positioned outside the liquid fuel nozzle 31, and a second combustion-supporting gas nozzle 33b positioned outside the first combustion-supporting gas nozzle 33a. The liquid fuel nozzle 31, the first combustion-supporting gas nozzle 33a, and the second combustion-supporting gas nozzle 33b form a multi-tube arranged substantially coaxially with respect to the burner axis X. Six hydrogen gas fuel nozzles 32 are positioned between the first combustion-supporting gas nozzle 33a and the second combustion-supporting gas nozzle 33b, immediately outside the first combustion-supporting gas nozzle 33a. These multiple hydrogen gas fuel nozzles 32 are distributed on a circumference centered on the burner axis X.

[0017] The liquid fuel nozzle 31 is connected to the liquid fuel supply pipe 41. Liquid fuel 21 is supplied from the liquid fuel source to the liquid fuel nozzle 31 through the liquid fuel supply pipe 41. The liquid fuel 21 may be any of the fuel oils such as kerosene, light oil, and heavy oil. Pressurized atomized liquid fuel 21 is ejected into the furnace from the liquid fuel outlet 61, which is the tip of the liquid fuel nozzle 31, approximately parallel to the burner axis X. The liquid fuel supply pipe 41 is provided with a liquid fuel adjustment device 51 for adjusting the amount of liquid fuel 21 injected from the liquid fuel outlet 61 per unit time (hereinafter referred to as the liquid fuel injection flow rate). The liquid fuel adjustment device 51 may include, for example, a flow rate adjustment valve and its drive device.

[0018] Each of the hydrogen gas fuel nozzles 32 is connected to a gas fuel supply pipe 42. Hydrogen gas fuel 22 is supplied from a hydrogen gas fuel source to the hydrogen gas fuel nozzles 32 through the gas fuel supply pipe 42. The hydrogen gas fuel 22 is a gas fuel containing hydrogen gas. The hydrogen gas fuel 22 may contain components other than hydrogen gas. Although not particularly limited, from the viewpoint of combustion efficiency, any gas containing 10% by mass or more of hydrogen is suitable as the hydrogen gas fuel 22. The hydrogen contained in the hydrogen gas fuel 22 may be hydrogen obtained by electrolysis of water, hydrogen contained in by-product gases of various plants, hydrogen obtained by vaporizing liquid hydrogen, etc., and is not particularly limited.

[0019] From the gas fuel outlet 62, which is the tip of the hydrogen gas fuel nozzle 32, hydrogen gas fuel 22 is ejected into the reactor approximately parallel to the burner axis X. The gas fuel supply pipe 42 is provided with a gas fuel adjustment device 52 for adjusting the amount of hydrogen gas fuel 22 ejected per unit time from the gas fuel outlet 62 (hereinafter referred to as the gas fuel ejection flow rate). The gas fuel ejection flow rate is the sum of the flow rates of hydrogen gas fuel 22 ejected from all hydrogen gas fuel nozzles 32 equipped with the burner 10. The gas fuel adjustment device 52 may include, for example, a flow rate adjustment valve and its drive device.

[0020] The first combustion-supporting gas nozzle 33a is connected to a combustion-supporting gas supply pipe 43. Combustion-supporting gas 23 is supplied from a combustion-supporting gas source to the first combustion-supporting gas nozzle 33a through the combustion-supporting gas supply pipe 43. The combustion-supporting gas 23 is air or oxygen gas. A first combustion-supporting gas flow path 36 is formed between the liquid fuel nozzle 31 and the first combustion-supporting gas nozzle 33a. A first swirler 37 is placed in the first combustion-supporting gas flow path 36. The combustion-supporting gas 23 introduced into the first combustion-supporting gas flow path 36 swirls upon contact with the first swirler 37 and is ejected as a swirling flow from the first combustion-supporting gas outlet 63, which is the tip of the first combustion-supporting gas nozzle 33a. The amount of combustion-supporting gas 23 ejected from the first combustion-supporting gas outlet 63 per unit time (hereinafter referred to as the first combustion-supporting gas supply amount) is adjusted by the first combustion-supporting gas adjustment device 53. If the combustion-supporting gas 23 is oxygen, the first combustion-supporting gas adjustment device 53 may include, for example, a flow control valve and its drive mechanism. If the combustion-supporting gas 23 is air, the first combustion-supporting gas adjustment device 53 may include, for example, a blower.

[0021] The second combustion-supporting gas nozzle 33b is connected to a combustion-supporting gas supply pipe 43, and high-pressure, high-temperature combustion-supporting gas 23 is supplied to the second combustion-supporting gas nozzle 33b from a combustion-supporting gas supply source through the combustion-supporting gas supply pipe 43. A second combustion-supporting gas flow path 38 is formed between the second combustion-supporting gas nozzle 33b and the hydrogen gas fuel nozzle 32. A second swirler 39 is positioned in the second combustion-supporting gas flow path 38. The combustion-supporting gas 23 introduced into the second combustion-supporting gas flow path 38 swirls upon contact with the second swirler 39 and is ejected as a swirling flow from the second combustion-supporting gas outlet 64, which is the tip of the second combustion-supporting gas nozzle 33b. The amount of combustion-supporting gas 23 ejected from the second combustion-supporting gas outlet 64 per unit time (hereinafter referred to as the second combustion-supporting gas supply amount) is adjusted by a second combustion-supporting gas adjustment device 54. If the combustion-supporting gas 23 is oxygen, the second combustion-supporting gas adjustment device 54 may include, for example, a flow control valve and its drive device. If the combustion-supporting gas 23 is air, the second combustion-supporting gas adjustment device 54 may include, for example, a blower. In this embodiment, the same type of combustion-supporting gas 23 is supplied to the first combustion-supporting gas nozzle 33a and the second combustion-supporting gas nozzle 33b, but the types of combustion-supporting gas 23 supplied to the first combustion-supporting gas nozzle 33a and the second combustion-supporting gas nozzle 33b may be different from each other.

[0022] In the burner 10 with the above configuration, an annular first combustion-supporting gas outlet 63 is arranged around the liquid fuel outlet 61, a plurality of gas fuel outlets 62 are arranged around the first combustion-supporting gas outlet 63 in a circumferential direction with respect to the burner axis X, and an annular second combustion-supporting gas outlet 64 is arranged around the plurality of gas fuel outlets 62. As a result, combustion-supporting gas 23 (first combustion-supporting gas) is ejected from the first combustion-supporting gas outlet 63 so as to surround the liquid fuel 21 ejected from the liquid fuel outlet 61, hydrogen gas fuel 22 is ejected from the plurality of gas fuel outlets 62 so as to surround the combustion-supporting gas 23 ejected from the first combustion-supporting gas outlet 63, and combustion-supporting gas 23 (second combustion-supporting gas) is ejected from the second combustion-supporting gas outlet 64 so as to surround the hydrogen gas fuel 22 ejected from the plurality of gas fuel outlets 62.

[0023] Although the burner 10 described above is equipped with multiple hydrogen gas fuel nozzles 32, the burner 10 may be equipped with a single hydrogen gas fuel nozzle 32. In this case, as shown in Figure 10, it may have a quadruple-tube structure in which a liquid fuel nozzle 31, a first combustion-supporting gas nozzle 33a, a hydrogen gas fuel nozzle 32, and a second combustion-supporting gas nozzle 33b are arranged coaxially from the inside out.

[0024] Returning to Figures 1 and 2, the burner 10 (or combustion furnace 1) is equipped with a flame length measuring instrument 71 for measuring the flame length L. The flame length measuring instrument 71 measures the flame length of the liquid fuel 21 and the flame length of the hydrogen gas fuel 22. The flames of the liquid fuel 21 and the hydrogen gas fuel 22 may be measured separately. Alternatively, the flame lengths of the liquid fuel 21 and the hydrogen gas fuel 22 may be measured without distinction. The flame lengths of the liquid fuel 21 and the hydrogen gas fuel 22 may be measured by a single flame length measuring instrument 71. Alternatively, a separate flame length measuring instrument 71 may be provided for measuring the flame length of the liquid fuel 21 and a separate flame length measuring instrument 71 for measuring the flame length of the hydrogen gas fuel 22. The flame length measured by the flame length measuring instrument 71 may be a specific numerical value, an approximate number, or an index value based on a predetermined indicator (e.g., short, medium, long, 1, 2, 3, etc.). The flame length measuring instrument 71 may also detect whether the flame length exceeds a predetermined threshold. The method for measuring the flame length using the flame length measuring instrument 71 is not particularly limited, and any known flame length measurement method may be employed.

[0025] For example, by using an optical bandpass filter to extract light with high spectral intensity (e.g., ultraviolet light) from the emission spectrum of a hydrogen flame (or fuel oil flame), amplifying it, and converting it into an electrical signal with a CCD camera, the hydrogen flame (or fuel oil flame) can be visualized as an image. The distance between the tip of the imaged flame and the nozzle of the burner 10 (in this case, the liquid fuel outlet 61), parallel to the burner axis X, can then be measured as the "flame length L".

[0026] Furthermore, for example, by using a thermal camera to collect infrared light from blackbody radiation emitted from pipes and walls surrounding the flame, the high-temperature region around the flame can be visualized as an infrared image (i.e., a thermal image). By processing this visualized image, the outline of the flame can be extracted, and the distance parallel to the burner axis X between the tip of the flame and the nozzle of the burner 10 can be measured as the "flame length L".

[0027] Furthermore, for example, multiple temperature sensors can be placed on the wall surrounding the flame, distributed parallel to the burner axis X, and the tip of the flame can be estimated based on the temperatures detected by the multiple temperature sensors. The distance between the tip of the flame and the nozzle of the burner 10, parallel to the burner axis X, can then be measured as the "flame length L".

[0028] Figure 3 is a block diagram showing the configuration of the control system of the burner 10. As shown in Figure 3, the burner 10 (or combustion furnace 1) is equipped with a controller 70. The controller 70 is equipped with a processor 75, a memory 76 readable by the processor 75, and an I / O 77. The memory 76 stores basic programs and application programs executed by the processor 75. The controller 70 is connected to an external storage device via the I / O 77. The controller 70 is also electrically connected to a liquid fuel adjustment device 51, a gas fuel adjustment device 52, a first combustion-supporting gas adjustment device 53, and a second combustion-supporting gas adjustment device 54 via the I / O 77. The controller 70 operates the liquid fuel adjustment device 51, the gas fuel adjustment device 52, the first combustion-supporting gas adjustment device 53, and the second combustion-supporting gas adjustment device 54 to adjust the liquid fuel injection flow rate, the gas fuel injection flow rate, the first combustion-supporting gas supply amount, and the second combustion-supporting gas supply amount. The controller 70 is electrically connected to the flame length measuring instrument 71 via I / O 77, and can acquire the flame length L measured by the flame length measuring instrument 71.

[0029] The controller 70 functions as a flame length control unit 70a by having the processor 75 read and execute a predetermined program stored in the memory 76. The flame length control unit 70a performs flame length control processing to control the flame length L by adjusting the mixing ratio of liquid fuel 21 and hydrogen gas fuel 22.

[0030] Figure 4 is Table 1, which shows an example of the relationship between the co-firing ratio of liquid fuel 21 and hydrogen gas fuel 22 and the flame length L. The horizontal axis of Table 1 represents the co-firing ratio [%], and the vertical axis represents the flame length ratio when the flame length L when hydrogen gas fuel 22 is burned exclusively is set to 1.0. Here, the co-firing ratio [%] is the ratio of the heat energy of hydrogen gas fuel 22 to the heat input, and is expressed as heat energy of hydrogen gas fuel 22 / heat input × 100. The heat input is the sum of the heat energy of liquid fuel 21 and the heat energy of hydrogen gas fuel 22 (= heat energy of liquid fuel 21 + heat energy of hydrogen gas fuel 22). In Table 1, the relationship between the co-firing ratio and the flame length ratio is shown when the heat input, combustion-supporting gas supply amount, and combustion speed of each fuel are fixed values, and the burner 10 is operated under the condition of continuous maximum output MCR. Hydrogen gas fuel 22 is 100% hydrogen gas, and liquid fuel 21 is diesel fuel.

[0031] The relationship between the co-firing ratio and the flame length ratio is represented as a waveform with approximately one period, in which the maximum and minimum values ​​of the flame length ratio appear sequentially as the co-firing ratio increases. When the co-firing ratio is 0%, i.e., when liquid fuel 21 is exclusively burned, the flame length ratio is greater than when hydrogen gas fuel 22 is exclusively burned. In region A, from the co-firing ratio of 0% to the co-firing ratio at which the flame length ratio is maximum (approximately 20% in this example), the flame length ratio continuously increases from approximately 1.2 to approximately 1.7 as the co-firing ratio increases. In region B, from the co-firing ratio at which the flame length ratio is maximum (approximately 20% in this example) to the co-firing ratio at which the flame length ratio is minimum (approximately 80% in this example), the flame length ratio continuously decreases from approximately 1.7 to approximately 0.5 as the co-firing ratio increases. At a co-firing ratio near the middle of region B (approximately 55% in this example), the flame length ratio is 1.0. In region C, from the co-combustion ratio at which the flame length ratio is minimized (approximately 80% in this example) to 100% co-combustion ratio, the flame length ratio continuously increases from approximately 0.5 to 1.0 as the co-combustion ratio increases. Note that Figure 1 shows the trend of change in the flame length ratio with increasing (or decreasing) co-combustion ratio, but the values ​​are merely examples and are not limiting.

[0032] The flame length L during pure combustion can be estimated based on the fuel flow rate, burner diameter, and fuel diffusion coefficient. However, during mixed combustion, the reaction ratio of the combustion-supporting gas 23 changes according to the combustion ratio due to the difference in combustion rates between the liquid fuel 21 and the hydrogen gas fuel 22. As a result, the time it takes for each fuel to completely combust and form a flame changes, which is thought to cause the flame length L to change in a complex manner.

[0033] At a co-firing ratio of 0%, the flame length ratio is expected to be longer than 1.0 because the liquid fuel 21, which burns more slowly than the hydrogen gas fuel 22, burns first. In region A, as the co-firing ratio increases, the amount of combustion-supporting gas 23 supplied to the liquid fuel 21 becomes insufficient, and as a result, the time it takes for the fuel to burn completely increases, which is expected to increase the flame length ratio. In region B, as the co-firing ratio increases, the amount of hydrogen gas fuel 22, which burns faster, increases and the amount of liquid fuel 21, which burns slower, decreases, so the time it takes for the fuel to burn completely decreases, which is expected to decrease the flame length ratio. In region C, most of the combustion-supporting gas 23 supplied to the hydrogen gas fuel 22, which makes up the majority of the fuel, is distributed, and the combustion-supporting gas 23 is supplied to the liquid fuel 21 after the hydrogen gas fuel 22 has burned, so it takes longer for the fuel to burn completely, which is expected to increase the flame length ratio.

[0034] The relationship between the co-firing ratio and flame length L, as described above, differs precisely depending on various variables such as the components and concentration of the liquid fuel 21, the hydrogen concentration of the hydrogen gas fuel 22, the liquid fuel injection flow rate, the gas fuel injection flow rate, pressure, and temperature, but is considered to show a substantially similar trend. Therefore, the controller 70, which functions as a flame length control unit 70a, adjusts the co-firing ratio of the liquid fuel 21 and the hydrogen gas fuel 22 based on the pre-stored relationship between the co-firing ratio and flame length L so that the flame length L measured by the flame length measuring instrument 71 becomes the desired flame length. The adjustment of the co-firing ratio is performed by changing the liquid fuel injection flow rate and the gas fuel injection flow rate using the liquid fuel adjustment device 51 and the gas fuel adjustment device 52.

[0035] [Example 1 of application for burner 10] Figure 5 is a schematic diagram of a combustion furnace 1(1A) relating to application example 1 of burner 10. As shown in Figure 5, in application example 1, burner 10 is applied to the combustion furnace 1(1A) of a boiler, i.e., a boiler furnace. Although one burner 10 is shown in Figure 5, the combustion furnace 1 may be equipped with multiple burners 10. The burner 10 is installed on the furnace wall of the combustion furnace 1 so that the burner axis X is approximately horizontal. For the combustion furnace 1, an appropriate numerical range of flame length according to the furnace size (hereinafter referred to as the appropriate flame length range Lp) is predetermined and set in the controller 70. In addition, the relationship between the co-firing ratio and the flame length L for the liquid fuel 21 and hydrogen gas fuel 22 used in the combustion furnace 1 is determined in advance by experiment or simulation and stored in the memory 76 or storage device of the controller 70.

[0036] The controller 70 can determine the target heat input value Ht based on the input request. The calculation formula for determining the target heat input value Ht based on the request is pre-stored in the controller 70's memory 76 or storage device. The request may be, for example, the amount of steam generated by the boiler or a command value for the heat input. The controller 70 can also acquire the target heat input value Ht. The target heat input value Ht acquired by the controller 70 may be calculated by the controller 70 itself, or it may be acquired from an input device or other device connected to the controller 70 wirelessly or via a wired connection.

[0037] The controller 70 can determine the amount of combustion-supporting gas supplied based on the target heat input value Ht. The amount of combustion-supporting gas supplied is roughly proportional to the target heat input value Ht. The formula for calculating the amount of combustion-supporting gas supplied based on the target heat input value Ht is pre-stored in the controller 70's memory 76 or storage device.

[0038] The controller 70 can determine the liquid fuel injection flow rate and the gas fuel injection flow rate based on the target heat input value Ht and the co-firing ratio, such that the sum of the heat content of the liquid fuel 21 in the liquid fuel injection flow rate and the heat content of the hydrogen gas fuel 22 in the gas fuel injection flow rate equals the target heat input value Ht. The calculation formulas for determining the liquid fuel injection flow rate and the gas fuel injection flow rate based on the target heat input value Ht and the co-firing ratio are pre-stored in the memory 76 or storage device of the controller 70. Here, it is desirable that the co-firing ratio of the liquid fuel 21 and the hydrogen gas fuel 22 corresponds to a value in the range from the maximum to the minimum value of the flame length ratio (region B shown in Figure 4) in the relationship between the co-firing ratio and the flame length L.

[0039] Figure 6 is a flowchart of the flame length control process by the controller 70. As shown in Figure 6, when the controller 70 obtains a new heat input target value Ht, it updates the heat input target value Ht with the new heat input target value Ht. The new heat input target value Ht is different from the current heat input target value Ht. When the heat input target value Ht is updated (YES in step S01), the controller 70 determines the liquid fuel injection flow rate, gas fuel injection flow rate, and combustion-supporting gas supply amount based on the updated heat input target value Ht (step S02). Here, in order to determine the liquid fuel injection flow rate and gas fuel injection flow rate, the current co-firing ratio of liquid fuel 21 and hydrogen gas fuel 22, a preset standard co-firing ratio, or a newly acquired co-firing ratio by the controller 70 may be used.

[0040] The controller 70 operates the liquid fuel adjustment device 51 and the gas fuel adjustment device 52 so that fuel injection is performed at the determined liquid fuel injection flow rate and gas fuel injection flow rate, and also operates the first combustion-supporting gas adjustment device 53 and the second combustion-supporting gas adjustment device 54 so that the determined amount of combustion-supporting gas supplied for liquid fuel 21 is supplied.

[0041] During the operation of the combustion furnace 1, the controller 70 monitors the flame length L measured by the flame length measuring instrument 71. Here, the controller 70 acquires the flame length L measured by the flame length measuring instrument 71 (step S04) and compares the measured flame length L with the flame length appropriate range Lp. If the measured flame length L is within the flame length appropriate range Lp (YES in step S05), the controller 70 continues to monitor the flame length L.

[0042] If the measured flame length L falls outside the appropriate flame length range Lp (NO in step S05), the controller 70 corrects the current co-firing ratio (step S06). If the measured flame length L falls below the appropriate flame length range Lp, the controller 70 corrects the co-firing ratio of the liquid fuel 21 and hydrogen gas fuel 22 so that the proportion of hydrogen gas fuel 22 decreases. If the measured flame length L exceeds the appropriate flame length range Lp, the controller 70 corrects the co-firing ratio of the liquid fuel 21 and hydrogen gas fuel 22 so that the proportion of hydrogen gas fuel 22 increases. The amount of correction to the co-firing ratio may be a predetermined value, for example, 1%, or the amount of correction may be adjusted according to the degree of deviation of the flame length L from the appropriate flame length range Lp.

[0043] The controller 70 determines the corrected liquid fuel injection flow rate and gas fuel injection flow rate based on the target heat input value Ht and the corrected co-firing ratio. For the corrected liquid fuel injection flow rate and gas fuel injection flow rate, the sum of the heat content of the liquid fuel 21 in the liquid fuel injection flow rate and the heat content of the hydrogen gas fuel 22 in the gas fuel injection flow rate becomes the target heat input value Ht.

[0044] The controller 70 updates the co-firing ratio with the corrected ratio and operates the liquid fuel adjuster 51 and the gas fuel adjuster 52 so that fuel injection is performed with the corrected liquid fuel injection flow rate and gas fuel injection flow rate. In other words, the controller 70 operates to lower the co-firing ratio of hydrogen gas fuel 22 when the flame length L falls below the appropriate flame length range Lp, and operates to increase the co-firing ratio of hydrogen gas fuel 22 when the measured flame length L exceeds the appropriate flame length range Lp. In this way, the controller 70 controls the flame length so that the flame length L can be maintained within the appropriate flame length range Lp even if the heat input changes. This prevents burnout of the furnace wall.

[0045] [Example 2 of application of burner 10] Figure 7 is a schematic diagram of a combustion furnace 1(1B) according to application example 2 of burner 10. As shown in Figure 7, in application example 2, burner 10 is applied to a horizontal combustion furnace 1(1B) such as a rotary kiln. In this combustion furnace 1, raw materials are supplied from the starting end, which is one end in the longitudinal direction of the furnace body, and the burned raw materials are discharged from the ending end, which is the other end in the longitudinal direction of the furnace body. The burner 10 is installed on the furnace wall at the end of the furnace body so that the burner axis X is approximately horizontal. With this burner 10, the flame length L can be adjusted arbitrarily.

[0046] The relationship between the co-firing ratio and the flame length L for the liquid fuel 21 and hydrogen gas fuel 22 used in the combustion furnace 1 is determined in advance through experiments or simulations and stored in the memory 76 or storage device of the controller 70.

[0047] The controller 70 can acquire a target heat input value Ht. The target heat input value Ht acquired by the controller 70 may be calculated by the controller 70 itself, or it may be acquired from an input device or other device connected to the controller 70 by wire or wireless.

[0048] The controller 70 can determine the amount of combustion-supporting gas supplied based on the target heat input value Ht. The amount of combustion-supporting gas supplied is proportional to the target heat input value Ht. The formula for calculating the amount of combustion-supporting gas supplied based on the target heat input value Ht is pre-stored in the controller 70's memory 76 or storage device.

[0049] The controller 70 can obtain the flame length command value Lc. The flame length command value Lc may be a specific numerical value, or it may be an approximate number representing the length using a predetermined index such as "short, medium, long" or "1, 2, 3". The flame length command value Lc may be input to the controller 70 from an input device connected to the controller 70. Alternatively, the flame length command value Lc may be provided at an appropriate timing according to the combustion program set in the controller 70.

[0050] The controller 70 can determine the liquid fuel injection flow rate and the gas fuel injection flow rate based on the flame length command value Lc and the heat input target value Ht. The controller 70 refers to the relationship between the co-combustion ratio and the flame length L to determine the co-combustion ratio that yields a flame length L corresponding to the flame length command value Lc. Here, it is desirable that the co-combustion ratio is a value that corresponds to the range from the maximum to the minimum value of the flame length L in the relationship between the co-combustion ratio and the flame length L (region B shown in Figure 4). Based on the determined co-combustion ratio, the controller 70 calculates the liquid fuel injection flow rate and the gas fuel injection flow rate such that the sum of the heat content of the liquid fuel 21 in the liquid fuel injection flow rate and the heat content of the hydrogen gas fuel 22 in the gas fuel injection flow rate equals the heat input target value Ht. Note that the injection pressure of the liquid fuel 21 and the hydrogen gas fuel 22 is proportional to the injection flow rate, and the injection pressure corresponding to the injection flow rate may be predetermined. Furthermore, the temperatures of the liquid fuel 21, hydrogen gas fuel 22, and combustion-supporting gas 23 may be predetermined values.

[0051] Figure 8 is a flowchart of the flame length control process by the controller 70. As shown in Figure 8, when the controller 70 obtains a new combination of heat input target value Ht and flame length command value Lc, it updates the heat input target value Ht and flame length command value Lc with the new values. Here, the new combination of heat input target value Ht and flame length command value Lc only needs to have at least one of the heat input target value Ht and flame length command value Lc different from the current value. When the combination of heat input target value Ht and flame length command value Lc is updated (YES in step S11), the controller 70 determines the liquid fuel injection flow rate, gas fuel injection flow rate, and combustion-supporting gas supply amount based on the updated heat input target value Ht and flame length command value Lc (step S12). The co-firing ratio of liquid fuel 21 and hydrogen gas fuel 22 obtained in the calculation process of liquid fuel injection flow rate and gas fuel injection flow rate is set as the current co-firing ratio.

[0052] The controller 70 operates the liquid fuel adjustment device 51 and the gas fuel adjustment device 52 so that fuel injection is performed at the determined liquid fuel injection flow rate and gas fuel injection flow rate, and also operates the first combustion regulating gas adjustment device 53 and the second combustion regulating gas adjustment device 54 so that the determined amount of combustion regulating gas 23 is supplied (step S13).

[0053] In this way, the flame length L can be arbitrarily changed by the controller 70 controlling the flame length.

[0054] Furthermore, in this application example 2, the controller 70 may also be configured to monitor the flame length L during furnace operation. In this case, as shown in Figure 9, the controller 70 acquires the flame length L measured by the flame length measuring instrument 71 (step S14) and compares the measured flame length L with the appropriate flame length range Lp. Here, the appropriate flame length range Lp is the numerical range of the appropriate flame length L corresponding to the flame length command value Lc, and the controller 70 stores the appropriate flame length range Lp in association with the flame length command value Lc. Alternatively, the controller 70 may determine the appropriate flame length range Lp from the flame length command value Lc using a predetermined calculation formula. For example, if the flame length command value Lc is a specific numerical value, the appropriate flame length range Lp may be the flame length command value Lc plus the allowable values ​​on the positive and negative sides. Furthermore, if the flame length command value Lc is an approximate number representing the length using a predetermined index, a suitable flame length range Lp may be defined for each flame length command value Lc.

[0055] If the measured flame length L is within the appropriate flame length range Lp (YES in step S15), the controller 70 continues to monitor the flame length L. If the measured flame length L falls outside the appropriate flame length range Lp (NO in step S15), the controller 70 corrects the current co-firing ratio (step S16). Here, if the measured flame length L falls below the appropriate flame length range Lp, the controller 70 corrects the co-firing ratio of the liquid fuel 21 and hydrogen gas fuel 22 so that the proportion of hydrogen gas fuel 22 decreases. Also, if the measured flame length L exceeds the appropriate flame length range Lp, the controller 70 corrects the co-firing ratio of the liquid fuel 21 and hydrogen gas fuel 22 so that the proportion of hydrogen gas fuel 22 increases. The amount of adjustment for the co-firing ratio may be a predetermined value, such as 1% increments, or it may be adjusted based on the degree of deviation of the flame length L from the optimal flame length range Lp.

[0056] The controller 70 determines the corrected liquid fuel injection flow rate and gas fuel injection flow rate based on the target heat input value Ht and the corrected co-firing ratio. For the corrected liquid fuel injection flow rate and gas fuel injection flow rate, the sum of the heat content of the liquid fuel 21 in the liquid fuel injection flow rate and the heat content of the hydrogen gas fuel 22 in the gas fuel injection flow rate becomes the target heat input value Ht.

[0057] The controller 70 updates the combustion ratio with the corrected ratio and operates the liquid fuel adjuster 51 and the gas fuel adjuster 52 so that fuel injection is performed with the corrected liquid fuel injection flow rate and gas fuel injection flow rate. In other words, the controller 70 operates to lower the combustion ratio of hydrogen gas fuel 22 when the flame length L falls below the appropriate flame length range Lp, and operates to increase the combustion ratio of hydrogen gas fuel 22 when the measured flame length L exceeds the appropriate flame length range Lp. In this way, the controller 70 controls the flame length so that the flame length L can be maintained at a value corresponding to the flame length command value Lc.

[0058] [Summary] As explained above, the diffusion combustion type dual fuel burner 10 relating to this disclosure is At least one liquid fuel nozzle 31 that ejects liquid fuel 21 at a liquid fuel injection flow rate, A hydrogen gas fuel nozzle 32 is provided around the liquid fuel nozzle 31 and ejects hydrogen gas fuel 22 at a gas fuel injection flow rate, At least one combustion-supporting gas nozzle 33 supplies combustion-supporting gas 23 to the liquid fuel 21 ejected from the liquid fuel nozzle 31 and the hydrogen gas fuel 22 ejected from the hydrogen gas fuel nozzle 32, A liquid fuel adjustment device 51 that adjusts the liquid fuel injection flow rate, A gas fuel adjustment device 52 that adjusts the gas fuel injection flow rate, A controller 70 controls the operation of the liquid fuel adjustment device 51 and the gas fuel adjustment device 52, The system includes a flame length measuring instrument 71 for measuring the flame length L of the flame produced by the combustion of liquid fuel 21 and hydrogen gas fuel 22.

[0059] In the burner 10 configured as described above, the controller 70 acquires the flame length L measured by the flame length measuring instrument 71, and if the flame length L falls outside the pre-stored optimal flame length range Lp, it corrects the current mixing ratio of liquid fuel 21 and hydrogen gas fuel 22 so that the flame length L falls within the optimal flame length range Lp, and operates the liquid fuel adjustment device 51 and the gas fuel adjustment device 52 so that the liquid fuel 21 and hydrogen gas fuel 22 are burned at the corrected mixing ratio.

[0060] Similarly, the flame length control method for the diffusion combustion type dual fuel burner 10 according to this disclosure is: A flame length control method for a diffusion combustion type dual fuel burner 10 that diffusely burns a dual fuel consisting of a liquid fuel 21 and a hydrogen gas fuel 22, To obtain the flame length L of the flame produced by the combustion of liquid fuel 21 and hydrogen gas fuel 22. To acquire the given flame length suitability range Lp, and, If the flame length L falls outside the optimal flame length range Lp, the current mixing ratio of liquid fuel 21 and hydrogen gas fuel 22 shall be adjusted so that the flame length L falls within the optimal flame length range Lp, and, This includes burning liquid fuel 21 and hydrogen gas fuel 22 at a modified co-combustion ratio.

[0061] In the burner 10 with the above configuration, the controller 70 may be configured to modify the co-firing ratio so that the proportion of hydrogen gas fuel 22 decreases when the flame length L falls below the appropriate flame length range Lp.

[0062] In the burner 10 with the above configuration, the controller 70 may be configured to modify the co-firing ratio so that the proportion of hydrogen gas fuel 22 increases when the flame length L exceeds the appropriate flame length range Lp.

[0063] According to the burner 10 and its flame length control method described above, the flame length L can be controlled to the optimal flame length range Lp by adjusting the mixing ratio of the liquid fuel 21 and the hydrogen gas fuel 22. Since the optimal flame length range Lp can be set arbitrarily, any flame length L can be formed according to the size of the combustion furnace 1. It is also possible to apply a burner 10 of the same structure to multiple furnaces with different optimal flame length ranges Lp.

[0064] In the burner 10 with the above configuration, the heat input is the sum of the heat content of the injected liquid fuel 21 and the heat content of the injected hydrogen gas fuel 22. The controller 70 modifies the liquid fuel injection flow rate and the gas fuel injection flow rate based on the modified co-firing ratio so that the heat input remains constant before and after the co-firing ratio is modified. The controller 70 is configured to operate the liquid fuel adjustment device 51 so that liquid fuel 21 at the liquid fuel injection flow rate is injected, and the gas fuel adjustment device 52 so that hydrogen gas fuel 22 at the modified gas fuel injection flow rate is injected.

[0065] According to the burner 10 described above, the flame length can be changed while maintaining a nearly constant heat input.

[0066] Furthermore, in the burner 10 with the above configuration, the controller 70 may be configured to acquire a target heat input value Ht and a flame length command value Lc, acquire the relationship between the co-firing ratio of a given liquid fuel 21 and hydrogen gas fuel 22 and the flame length L, use this relationship to determine the co-firing ratio corresponding to the flame length command value Lc, determine the liquid fuel injection flow rate and the gas fuel injection flow rate based on the co-firing ratio and the target heat input value Ht, operate the liquid fuel adjustment device 51 so that liquid fuel 21 at the liquid fuel injection flow rate is injected, and operate the gas fuel adjustment device 52 so that hydrogen gas fuel 22 at the gas fuel injection flow rate is injected.

[0067] Similarly, the flame length control method for a diffusion combustion type dual fuel burner 10 according to the present disclosure is a flame length control method for a diffusion combustion type dual fuel burner 10 that diffusely burns a dual fuel consisting of a liquid fuel 21 and a hydrogen gas fuel 22, Obtain the target heat input value Ht and the flame length command value Lc. To obtain the relationship between the co-firing ratio of a given liquid fuel 21 and hydrogen gas fuel 22 and the flame length L. Using this relationship, determine the flame length command value Lc and the corresponding co-combustion ratio. The sum of the heat energy of the ejected liquid fuel 21 and the heat energy of the ejected hydrogen gas fuel 22 is taken as the heat input, and the liquid fuel injection flow rate and the gas fuel injection flow rate are determined based on the co-firing ratio and the target heat input value Ht, and, This includes injecting liquid fuel 21 at a liquid fuel injection flow rate and injecting hydrogen gas fuel 22 at a gas fuel injection flow rate.

[0068] According to the burner 10 and its flame length control method described above, the flame length L can be controlled to a flame length command value Lc. Since the flame length command value Lc is an arbitrary value, any flame length L can be formed according to the size of the combustion furnace 1. Furthermore, it is possible to arbitrarily change the flame length L of the burner 10 in a single furnace.

[0069] The functions of the controller 70 disclosed herein can be performed using general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, or processing circuits configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0070] The foregoing discussions in this disclosure are presented for illustrative and explanatory purposes only and are not intended to limit this disclosure to the forms disclosed herein. For example, in the foregoing detailed description, various features of this disclosure are grouped into a single embodiment for the purpose of streamlining the disclosure. However, some of the features contained herein can be combined into alternative embodiments, configurations, or aspects other than those discussed above. [Explanation of symbols]

[0071] 1: Combustion furnace 10: Burner 21 :Liquid fuel 22: Hydrogen gas fuel 23: Combustion-supporting gas 31: Liquid fuel nozzle 32: Hydrogen gas fuel nozzle 33: Combustion-supporting gas nozzle 51:Liquid fuel adjustment device 52: Gas fuel adjustment device 70: Controller 70a: Flame length control unit 71: Flame length measuring instrument

Claims

1. A liquid fuel nozzle that ejects liquid fuel at a liquid fuel injection flow rate, A hydrogen gas fuel nozzle is provided around the liquid fuel nozzle and ejects hydrogen gas fuel at a gas fuel injection flow rate, A combustion-supporting gas nozzle that supplies a combustion-supporting gas to the liquid fuel ejected from the liquid fuel nozzle and the hydrogen gas fuel ejected from the hydrogen gas fuel nozzle, A gas fuel adjustment device that adjusts the gas fuel injection flow rate, A liquid fuel adjustment device for adjusting the liquid fuel injection flow rate, A controller that controls the operation of the liquid fuel adjustment device and the gas fuel adjustment device, The system includes a flame length measuring instrument for measuring the flame length of the flame produced by the combustion of the liquid fuel and the hydrogen gas fuel, The controller acquires the flame length measured by the flame length measuring instrument, and if the flame length falls outside a given suitable flame length range, it corrects the current mixing ratio of the liquid fuel and the hydrogen gas fuel so that the flame length falls within the suitable flame length range, and operates the liquid fuel adjustment device and the gas fuel adjustment device so that the liquid fuel and the hydrogen gas fuel are burned at the corrected mixing ratio. Diffusion combustion type dual fuel burner.

2. The controller modifies the co-firing ratio so that the proportion of hydrogen gas fuel decreases if the flame length falls below the appropriate flame length range. The diffusion combustion type dual fuel burner according to claim 1.

3. The controller modifies the co-firing ratio so that the proportion of hydrogen gas fuel increases if the flame length exceeds the appropriate flame length range. A diffusion combustion type dual fuel burner according to claim 1 or 2.

4. The sum of the heat energy of the ejected liquid fuel and the heat energy of the ejected hydrogen gas fuel is taken as the heat input. The controller modifies the liquid fuel injection flow rate and the gas fuel injection flow rate based on the modified co-firing ratio so that the amount of heat input remains constant before and after the modification of the co-firing ratio, operates the liquid fuel adjustment device so that the liquid fuel is injected at the modified liquid fuel injection flow rate, and operates the gas fuel adjustment device so that the hydrogen gas fuel is injected at the modified gas fuel injection flow rate. A diffusion combustion type dual fuel burner according to claim 1 or 2.

5. A liquid fuel nozzle that ejects liquid fuel at a liquid fuel injection flow rate, A hydrogen gas fuel nozzle is provided around the liquid fuel nozzle and ejects hydrogen gas fuel at a gas fuel injection flow rate, A combustion-supporting gas nozzle that supplies a combustion-supporting gas to the liquid fuel ejected from the liquid fuel nozzle and the hydrogen gas fuel ejected from the hydrogen gas fuel nozzle, A gas fuel adjustment device that adjusts the gas fuel injection flow rate, A liquid fuel adjustment device for adjusting the liquid fuel injection flow rate, The system includes a controller that controls the operation of the liquid fuel adjustment device and the gas fuel adjustment device, The controller acquires a target heat input value and a flame length command value, acquires the relationship between the co-firing ratio of a given liquid fuel and hydrogen gas fuel and the flame length, uses this relationship to determine the co-firing ratio corresponding to the flame length command value, determines the liquid fuel injection flow rate and the gas fuel injection flow rate based on the co-firing ratio and the target heat input value, operates the liquid fuel adjustment device so that the liquid fuel is injected at the liquid fuel injection flow rate, and operates the gas fuel adjustment device so that the hydrogen gas fuel is injected at the gas fuel injection flow rate. Diffusion combustion type dual fuel burner.

6. A flame length control method for a diffusion combustion type dual fuel burner that diffusely burns a dual fuel consisting of a liquid fuel and a hydrogen gas fuel, To obtain the flame length of the flame produced by the combustion of the liquid fuel and the hydrogen gas fuel, To obtain a given flame length suitability range, and, If the flame length falls outside the appropriate flame length range, the current mixing ratio of the liquid fuel and the hydrogen gas fuel is modified so that the flame length falls within the appropriate flame length range, and This includes burning the liquid fuel and the hydrogen gas fuel at a modified co-combustion ratio, A method for controlling the flame length of a diffusion combustion type dual fuel burner.

7. A flame length control method for a diffusion combustion type dual fuel burner that diffusely burns a dual fuel consisting of a liquid fuel and a hydrogen gas fuel, To obtain the target heat input value and the commanded flame length value, To obtain the relationship between the co-firing ratio of a given liquid fuel and hydrogen gas fuel and the flame length, Using the aforementioned relationship, determine the co-combustion ratio corresponding to the flame length command value. The sum of the heat content of the ejected liquid fuel and the heat content of the ejected hydrogen gas fuel is taken as the heat input, and the liquid fuel injection flow rate and the gas fuel injection flow rate are determined based on the co-firing ratio and the target heat input value, and, This includes injecting the liquid fuel at the aforementioned liquid fuel injection flow rate and injecting the hydrogen gas fuel at the aforementioned gas fuel injection flow rate. A method for controlling the flame length of a diffusion combustion type dual fuel burner.

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