Two-fluid injection nozzle, combustion system, and method for controlling the supply amount of liquefied fuel.

Abstract

To provide a two-fluid injection nozzle, a combustion system, and a method for controlling the supply amount of liquefied fuel which can stabilize the flow of liquefied fuel.SOLUTION: A two-fluid injection nozzle 59 includes at least one or more first injection holes 591 and at least one or more second injection holes 592 for injecting liquefied fuel and atomizing fluid and further includes: a first liquefied fuel supply path 571 and a first atomizing fluid supply path 521 for guiding the liquefied fuel and the atomizing fluid respectively to the first injection hole 591; and a second liquefied fuel supply path 572 and a second atomizing fluid supply path 522 for guiding the liquefied fuel and the atomizing fluid respectively to the second injection hole 592. Either the first liquefied fuel supply path 571 or the second liquefied fuel supply path 572 is thermally insulated from either the first atomizing fluid supply path 521 or the second atomizing fluid supply path 522.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] This disclosure relates to a two-fluid injection nozzle, a combustion system, and a method for controlling the supply amount of liquefied fuel. [Background technology]

[0002] Conventionally, two-fluid injection nozzles are known that atomize liquid fuel with vapor and then inject it. For example, in Patent Document 1, oil is used as the liquid fuel, and the oil and vapor are mixed at the tip of the two-fluid injection nozzle before being injected. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Microfilm of Utility Model Application No. 59-007564 (Utility Model Full Application No. 60-122623) [Overview of the project] [Problems that the invention aims to solve]

[0004] From the viewpoint of stabilizing the flow of liquid fuel, it is preferable to suppress vapor lock, where liquid fuel vaporizes inside a two-fluid injection nozzle. However, a configuration for achieving this is not disclosed in the above-mentioned patent document.

[0005] The object of this disclosure is to provide a two-fluid injection nozzle, a combustion system, and a method for controlling the supply amount of liquefied fuel that can stabilize the flow of liquefied fuel. [Means for solving the problem]

[0006] A two-fluid injection nozzle according to at least one embodiment of the present disclosure is: A two-fluid injection nozzle comprising at least one first injection port and at least one second injection port for injecting liquefied fuel and atomizing fluid, A first liquefied fuel supply passage and a first atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid to the first injection hole, respectively, The present invention further includes a second liquefied fuel supply channel and a second atomizing fluid supply channel for guiding the liquefied fuel and the atomizing fluid, respectively, to the second injection port, The first liquefied fuel supply passage or the second liquefied fuel supply passage is thermally insulated from the first atomizing fluid supply passage or the second atomizing fluid supply passage.

[0007] A combustion system according to at least one embodiment of this disclosure is The above two-fluid injection nozzle, A plurality of liquefied fuel valves for independently changing the supply of liquefied fuel in the first liquefied fuel supply passage and the second liquefied fuel supply passage, A plurality of atomizing fluid valves for independently changing the supply of the atomizing fluid in the first atomizing fluid supply passage and the second atomizing fluid supply passage, It is equipped with.

[0008] A method for controlling the supply amount of liquefied fuel according to at least one embodiment of this disclosure is: A method for controlling the supply amount of liquefied fuel using the above-described combustion system, The method includes a step of independently changing the supply of the liquefied fuel in the first liquefied fuel supply line and the second liquefied fuel supply line, respectively. [Effects of the Invention]

[0009] This disclosure provides a two-fluid injection nozzle, a combustion system, and a method for controlling the supply amount of liquefied fuel, which can stabilize the flow of liquefied fuel. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a combustion system according to one embodiment of the present disclosure. [Figure 2]It is a conceptual configuration diagram of a supply unit according to an embodiment of the present disclosure. [Figure 3] It is a graph conceptually showing the relationship between the flow rate of liquefied fuel injected from a two-fluid injection nozzle according to an embodiment of the present disclosure and the supply pressure of the liquefied fuel. [Figure 4] It is a schematic configuration diagram of a burner according to an embodiment of the present disclosure. [Figure 5] It is a graph conceptually showing the relationship between the supply pressure of liquefied fuel and the injection flow rate according to an embodiment of the present disclosure. [Figure 6] It is a schematic explanatory diagram of a two-fluid injection nozzle according to an embodiment of the present disclosure. [Figure 7] It is a schematic explanatory diagram of a back plate according to an embodiment of the present disclosure. [Figure 8] It is a flowchart showing a method for supplying liquefied fuel and an atomizing fluid according to an embodiment of the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. Note that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included. In the following description, "upper" or "above" indicates the upper side in the vertical direction, and "lower" or "below" indicates the lower side in the vertical direction. The vertical direction is not strict and includes errors. In addition, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent a state of being relatively displaced with tolerances or at an angle or distance that can obtain the same function. For example, expressions indicating that things such as "identical", "equal", and "homogeneous" are in an equal state shall not only represent a strictly equal state, but also represent a state in which there is a tolerance or a difference within the range where the same function can be obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape shall not only represent shapes such as a square shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including concave and convex portions, chamfered portions, etc. within the range where the same effect can be obtained. On the other hand, expressions such as "comprising", "including", or "having" one component are not exclusive expressions that exclude the existence of other components. Note that the same reference numerals may be given to the same configurations and the description may be omitted.

[0012] <1. Overall configuration of combustion system 1> FIG. 1 is a schematic configuration diagram showing a combustion system including a boiler that uses solid fuel and liquefied fuel as main fuels. The liquefied fuel is a fuel that becomes a gas phase at room temperature under atmospheric pressure. The room temperature referred to in this specification is 35°C. The liquefied fuel is, for example, petroleum (light oil or liquefied petroleum gas), liquefied natural gas, dimethyl ether, and liquid ammonia. In the following description, unless otherwise specified, the liquefied fuel shall refer to liquid ammonia.

[0013] The boiler 10 included in the combustion system 1 of the present embodiment is a boiler capable of burning pulverized fuel obtained by pulverizing solid fuel and liquefied fuel by a burner, and exchanging heat between the heat generated by this combustion and feed water or steam to generate superheated steam. As the solid fuel, biomass fuel, coal, etc. are used.

[0014] The boiler 10 has a furnace 11, combustion devices 20 and 50, and a combustion gas passage 12. The furnace 11 has a hollow shape of a square cylinder and is installed along the vertical direction. The furnace wall 101 constituting the inner wall surface of the furnace 11 is composed of a plurality of heat transfer tubes and fins connecting the heat transfer tubes to each other, and recovers the heat generated by the combustion of the pulverized fuel by exchanging heat with water or steam flowing inside the heat transfer tubes, and suppresses the temperature rise of the furnace wall 101.

[0015] The combustion devices 20 and 50 are installed in the lower region of the furnace 11. In this embodiment, the combustion device 20 is configured to inject pulverized fuel into the furnace 11. The combustion device 50 is configured to atomize liquefied fuel using an atomizing fluid (spray medium) and inject it into the furnace 11. The atomizing fluid in this embodiment is atomized vapor.

[0016] The combustion device 20 has a plurality of burners 21 mounted on the furnace wall 101, and the combustion device 50 has a plurality of burners 51. Each burner 21 is provided with an injection nozzle (not shown) configured to inject pulverized fuel into the furnace 11 at its tip. In addition, each burner 51 is provided with a two-fluid injection nozzle 59 (see Figure 4) configured to atomize liquefied fuel with an atomizing fluid and inject it into the furnace 11 at its tip. The burners 21 and 51 are arranged in multiple vertical rows, with each set consisting of four burners (for example, four burners placed at each corner of a rectangular furnace 11) arranged at equal intervals along the circumferential direction of the furnace 11. In the example shown in Figure 1, there are two rows of one set of burners 21 and four rows of one set of burners 51. Note that in Figure 1, for illustrative purposes, only two burners from one set are shown, and each set is labeled with reference numerals 21 and 51. The shape of the furnace, the number of burner rows, the number of burners in each row, and the arrangement of the burners are not limited to this embodiment.

[0017] Each burner 21 of the combustion device 20 is connected to a plurality of mills 31A and 31B (hereinafter sometimes collectively referred to as "mills 31") via a plurality of fine fuel supply pipes 22A and 22B (hereinafter sometimes collectively referred to as "fine fuel supply pipes 22"). Mills 31 are, for example, vertical roller mills in which a grinding table (not shown) is supported inside so as to be rotatable, and a plurality of grinding rollers (not shown) are supported above the grinding table so as to be rotatable in conjunction with the rotation of the grinding table. The solid fuel, which is ground by the cooperation of the grinding rollers and the grinding table, is conveyed to a classifier (not shown) provided in the mills 31 by primary air (conveyor gas, oxidizing gas) supplied to the mills 31. In the classifier, the fuel is classified into fine fuel with a particle size of a size or smaller suitable for combustion in the burner 21 and coarse fuel with a particle size larger than that. The fine fuel passes through the classifier and is supplied to the burner 21 via the fine fuel supply pipes 22 along with the primary air. The coarse fuel that did not pass through the classifier falls onto the grinding table inside the mill 31 due to its own weight and is re-ground.

[0018] The burner 51 of the combustion device 50 is connected to the supply unit 90. The supply unit 90 includes an atomizing fluid supply unit 60 for two fluid injection nozzles configured to supply atomizing fluid to the combustion device 50 (hereinafter sometimes simply referred to as "atomizing fluid supply unit 60") and a liquefied fuel supply unit 70 for two fluid injection nozzles configured to supply liquefied fuel to the combustion device 50 (hereinafter sometimes simply referred to as "liquefied fuel supply unit 70"). The controller 110 acquires the required injection flow rate of liquefied fuel at the burner 51, which is determined according to the combustion load in the boiler 10. By sending a control command to the supply unit 90 according to the required injection flow rate, the atomizing fluid supply unit 60 and the liquefied fuel supply unit 70 can adjust the supply amounts of atomizing fluid and liquefied fuel, respectively. Details of the configuration of the supply unit 90 will be described later. The required injection flow rate of liquefied fuel is the required injection flow rate of liquefied fuel per two-fluid injection nozzle 59 (see Figure 4) of each burner 51.

[0019] An air register 23 is provided on the outside of the furnace 11 at the mounting positions of the burners 21 and 51, and one end of an air duct 24 is connected to this air register 23. A forced draft fan (FDF) 32 is connected to the other end of the air duct 24. The air supplied from the forced draft fan 32 is heated by an air preheater 42 installed in the air duct 24 (details will be described later), and is supplied to the burner 21 as secondary air (combustion air, oxidizing gas) via the air register 23 and introduced into the furnace 11.

[0020] The combustion gas passage 12 is connected to the upper vertical part of the furnace 11. The combustion gas passage 12 is equipped with superheaters 102A, 102B, 102C (hereinafter sometimes collectively referred to as "superheater 102"), reheaters 103A, 103B (hereinafter sometimes collectively referred to as "reheater 103"), and an economizer 104 as heat exchangers for recovering heat from the combustion gas. Heat exchange takes place between the combustion gas generated in the furnace 11 and the feedwater or steam circulating inside each heat exchanger. Note that the arrangement and shape of each heat exchanger are not limited to the configuration shown in Figure 1.

[0021] Downstream of the combustion gas passage 12 is a flue 13 through which the combustion gas, whose heat has been recovered by the heat exchanger, is discharged. An air preheater (air heater) 42 is installed between the flue 13 and the air duct 24, and heat exchange takes place between the air flowing through the air duct 24 and the combustion gas flowing through the flue 13. By heating the primary air supplied to the mill 31 and the secondary air supplied to the burner 21, heat is further recovered from the combustion gas after heat exchange with water or steam.

[0022] Furthermore, a denitrification device 43 may be provided in the flue 13 at a position upstream of the air preheater 42. The denitrification device 43 supplies a reducing agent, such as ammonia or urea solution, which has the effect of reducing nitrogen oxides, to the combustion gas flowing through the flue 13. The reaction between the nitrogen oxides (NOx) in the combustion gas to which the reducing agent has been supplied and the reducing agent is promoted by the catalytic action of a denitrification catalyst installed in the denitrification device 43, thereby removing and reducing nitrogen oxides in the combustion gas. A gas duct 41 is connected downstream of the air preheater 42 in the flue 13. The gas duct 41 is equipped with dust collection devices 44, such as an electrostatic precipitator, to remove ash and other particles from the combustion gas, and environmental devices such as a desulfurization device 46 to remove sulfur oxides, as well as an induced draft fan (IDF) 45 to guide the exhaust gas to these environmental devices. The downstream end of the gas duct 41 is connected to the chimney 47, and the combustion gas treated by the environmental devices is discharged outside the system as exhaust gas.

[0023] In the boiler 10, when multiple mills 31 are driven, the crushed and classified fine fuel is supplied to the burner 21 via the fine fuel supply pipe 22 along with primary air. In addition, atomizing fluid and liquefied fuel are supplied to the burner 51 from the atomizing fluid supply unit 60 and the liquefied fuel supply unit 70, respectively. Furthermore, secondary air heated by the air preheater 42 is supplied to the burners 21 and 51 via the air duct 24 and the air register 23. Burner 21 injects a mixture of fine fuel and primary air into the furnace 11, along with secondary air. The fine fuel mixture injected into the furnace 11 ignites and reacts with the secondary air to form a flame. Burner 51 injects secondary air into the furnace 11 along with liquefied fuel atomized by the atomizing fluid. The liquefied fuel injected into the furnace 11 vaporizes into fuel gas, which reacts with the secondary air and burns. The high-temperature combustion gas generated by the combustion of the fine fuel and fuel gas rises inside the furnace 11 and flows into the combustion gas passage 12. Furthermore, the timing of injecting the liquefied fuel into the furnace 11 may be after the temperature inside the furnace 11 has risen to a certain temperature due to the combustion of the pulverized fuel. For example, after the pulverized fuel is exclusively burned when the boiler 10 is started up, the liquefied fuel may be injected into the furnace 11, and co-firing of the fuel gas produced from the vaporized liquefied fuel and the pulverized fuel may occur. After that, the injection of the pulverized fuel may be stopped, and the liquefied fuel may be exclusively burned. Furthermore, in this embodiment, air is used as the oxidizing gas (primary air, secondary air), but it may also be a gas with a higher or lower oxygen content than air, and stable combustion can be achieved in the furnace 11 by adjusting the ratio of oxygen to the supplied fuel amount to an appropriate range.

[0024] The combustion gas flowing into the combustion gas passage 12 undergoes heat exchange with water and steam in the superheater 102, reheater 103, and economizer 104 located inside the combustion gas passage 12, before being discharged into the flue 13. There, nitrogen oxides are removed in the denitrification device 43, and after heat exchange with primary and secondary air in the air preheater 42, it is further discharged into the gas duct 41. Ash and other contaminants are removed in the dust collector 44, and sulfur oxides are removed in the desulfurization device 46 before being discharged out of the system through the chimney 47. Note that the arrangement of each heat exchanger in the combustion gas passage 12 and each device from the flue 13 to the gas duct 41 does not necessarily have to be in the order described above with respect to the combustion gas flow.

[0025] In the embodiments described above, the boiler of the present disclosure was described as a boiler that uses solid fuel and liquefied fuel as fuel. Examples of solid fuels used in the boiler include coal, biomass fuel, petroleum coke (PC) fuel, and petroleum residue. Furthermore, the fuel used in boilers combined with liquefied fuel is not limited to solid fuels; liquid fuels such as heavy oil, light oil, heavy crude oil, and other petroleum products, as well as industrial wastewater, can also be used. In addition, gaseous fuels such as natural gas, various petroleum gases, and by-product gases generated in steelmaking processes can also be used. Furthermore, this can also be applied to co-firing boilers that use a combination of these various fuels.

[0026] <2. Configuration of the liquefied fuel supply unit 70> Referring to Figure 2, an example of the configuration of the liquefied fuel supply unit 70, which is a component of the supply unit 90 described above, is shown. Figure 2 is a conceptual configuration diagram of a supply unit according to one embodiment of this disclosure. Note that in Figure 2, the combustion device 20 (see Figure 1) is omitted for the sake of clarity in the drawing.

[0027] The liquefied fuel supply unit 70 includes a storage section 79 for storing liquefied fuel, a liquefied fuel supply line 75 for supplying the liquefied fuel stored in the storage section 79 to the two-fluid injection nozzle 59 of the burner 51, a heater 76 provided in the liquefied fuel supply line 75, and a liquefied fuel adjustment section 78 provided in the liquefied fuel supply line 75.

[0028] The storage unit 79 stores liquid ammonia, which is an example of a liquefied fuel. The downstream end of the liquefied fuel supply line 75 is connected to a liquefied fuel supply passage 57, which is a component of the two-fluid injection nozzle 59 provided by each of the multiple burners 51. A return passage 752 is provided in the upstream portion of the liquefied fuel supply line 75 to return a portion of the supplied liquefied fuel back to the storage unit 79. The heater 76 is configured to heat the liquefied fuel to a certain temperature without vaporizing it. The heat source for the heater 76 is, for example, auxiliary steam, which is part of the steam generated in the combustion system 1. Heating by the heater 76 makes the liquefied fuel injected into the furnace 11 more easily vaporized, thereby suppressing misfires in the furnace 11. Based on the measurement results of a thermometer 175 for measuring the temperature of the liquefied fuel heated by the heater 76, a control valve 81 provided in the auxiliary steam flow path is adjusted to adjust the amount of heating of the liquefied fuel in the heater 76. In this example, this adjustment is performed by a controller 110.

[0029] The liquefied fuel adjustment unit 78 is configured to adjust the supply pressure and flow rate of the liquefied fuel according to the required injection flow rate of the liquefied fuel as described above. The liquefied fuel adjustment unit 78 in this embodiment consists of a plurality of control valves 781 of different capacities arranged in parallel in the return passage 752 and a control valve 782 provided in the liquefied fuel supply line 75. The control valves 781 are, for example, pressure regulating valves, and the control valves 782 are, for example, flow rate regulating valves. In this example, the plurality of control valves 781 and control valves 782 are controlled by the controller 110 based on the measurement results of a pressure gauge 173 provided downstream of the branching point between the liquefied fuel supply line 75 and the return passage 752, and a flow meter 176 provided upstream of the branching point between the liquefied fuel supply line 75 and the liquid fuel supply line 57. As a more specific example, the controller 110 controls the plurality of control valves 781 and control valves 782 based on the measurement results of the pressure gauge 173 and the flow meter 176, respectively, so that a flow rate of liquefied fuel corresponding to the required injection flow rate is supplied to the burner 51.

[0030] In other embodiments, the liquefied fuel supply unit 70 may not include a storage section 79. For example, the liquefied fuel supply line 75 may be connected by pipeline to a vessel such as a large tank truck that stores liquefied fuel or to a facility that manufactures liquefied fuel.

[0031] <3. Configuration of the atomizing fluid supply unit 60> Referring to Figure 2, the configuration of the atomizing fluid supply unit 60, which is a component of the supply unit 90 described above, is illustrated. The atomizing fluid supply unit 60 includes an atomizing fluid supply line 55 for supplying atomizing fluid to the two-fluid injection nozzle 59 of the burner 51, a desuperheater 53 provided in the atomizing fluid supply line 55, and an atomizing fluid adjustment unit 58 provided in the atomizing fluid supply line 55. The atomizing fluid supply line 55 is connected to atomizing fluid supply passages 52, which are components of the two-fluid injection nozzle 59 provided in each of the multiple burners 51.

[0032] The desuperheater 53 is configured to reduce the temperature of the atomizing fluid to a certain temperature using a cooling medium that is at a lower temperature than the atomizing fluid. In this embodiment, the atomizing fluid is vapor, and the desuperheater 53 reduces the temperature of the atomizing fluid by mixing it with spray water. For example, a spray water control valve 54 provided in the spray water pipe is controlled by the controller 110 based on the measurement result of a thermometer 161 provided downstream of the desuperheater 53.

[0033] The atomizing fluid adjustment unit 58 is configured to adjust the supply pressure of the atomizing fluid according to the required injection flow rate of the liquefied fuel described above. In this embodiment, the atomizing fluid adjustment unit 58 consists of a plurality of control valves 581 with different capacities, arranged in parallel downstream of the desuperheater 53. In this example, the plurality of control valves 581 are controlled based on the measurement results of a pressure gauge 182 located downstream of the atomizing fluid adjustment unit 58. More specifically, as an example, the controller 110 controls each of the plurality of control valves 581 based on the measurement results of the pressure gauge 182 so that atomizing fluid at a pressure corresponding to the required injection flow rate of liquefied fuel is supplied to the burner 51.

[0034] <4.2 Flow rate control of liquefied fuel in the fluid injection nozzle 59> Referring to Figure 3, the details of flow rate control of liquefied fuel in the two-fluid injection nozzle 59 are illustrated. Figure 3 is a conceptual graph showing the relationship between the flow rate of liquefied fuel injected from a two-fluid injection nozzle according to one embodiment of the present disclosure and the supply pressure of the liquefied fuel. The horizontal axis of the graph in Figure 3 shows the flow rate (Q) of liquefied fuel injected from the two-fluid injection nozzle 59. The vertical axis of the graph shows the supply pressure (Pf) of the liquefied fuel. Pf0 and Pf1 on the vertical axis are the lower and upper burner pressures of the liquefied fuel required to achieve stable combustion in burner 51, respectively. V This is the lower supply pressure required to stably supply liquefied fuel to the burner 51, and is a value corresponding to the vapor pressure of the liquefied fuel at the temperature of the liquefied fuel heated by the heater 76.

[0035] In the graph, the conceptually represented graph line A shows the relationship between the flow rate and the supply pressure of the liquefied fuel when the supply pressure (Pa) of the atomizing fluid is Pa1. Graph lines B and C show the relationship between the flow rate and the supply pressure of the liquefied fuel when the supply pressure (Pa) of the atomizing fluid is Pa2 and Pa3, respectively. The following equation (1) holds true for the supply pressure (Pa) of the atomizing fluid. Pa1>Pa2>Pa3 ···(1) Furthermore, the atomization supply pressure (Pa) does not necessarily have to be three pressure levels; it is possible to control it with more or fewer pressures. Also, the minimum Pa pressure can be zero, meaning no atomizing fluid is supplied.

[0036] In this embodiment, the flow rate of liquefied fuel injected from the two-fluid injection nozzle 59 is adjusted by changing the supply pressure of the liquid fuel and the supply pressure of the atomizing fluid. The details are explained below using the case where the flow rate of liquefied fuel decreases from the state shown at point J1 to the state shown at point J4 in the graph as an example.

[0037] First, the liquefied fuel adjustment unit 78 maintains the liquefied fuel supply pressure (Pf) at Pf1, while the atomizing fluid adjustment unit 58 increases the atomizing fluid supply pressure (Pa) from Pa3 to Pa2. As a result, the liquefied fuel flow rate Q decreases from Q4 to Q3 (point J2). At this time, since the liquefied fuel supply pressure is maintained, the flow of the liquefied fuel tends to stabilize. Subsequently, the atomizing fluid adjustment unit 58 maintains the atomizing fluid supply pressure at Pa2, while the liquefied fuel adjustment unit 78 adjusts the liquefied fuel supply pressure from Pf1 to Pf d Lower it to (Pf d The piano will be discussed later. V (larger than). This reduces the flow rate of the liquefied fuel (point J3). Furthermore, the liquefied fuel adjustment unit 78 adjusts the supply pressure of the liquefied fuel to Pf d While maintaining this, the atomizing fluid adjustment unit 58 increases the supply pressure of the atomizing fluid from Pa2 to Pa1. As a result, the flow rate of the liquefied fuel decreases (point J4).

[0038] The advantages of controlling the flow rate of liquefied fuel by changing both the supply pressure of the liquefied fuel (Pf) and the supply pressure of the atomizing fluid (Pa) are as follows: The amount of liquefied fuel injected correlates with the supply pressure of the liquefied fuel. Therefore, for example, if the supply pressure of the atomizing fluid (Pa) is maintained at, for example, Pa3, and only the supply pressure of the liquefied fuel (Pf) is lowered in order to reduce the flow rate of liquefied fuel in response to a decrease in the required injection flow rate of liquefied fuel in the two-fluid injection nozzle 59, then the supply pressure of the liquefied fuel (Pf) will be the lower limit pressure of the supply. V The pressure tends to fall below this level. As a result, the supply pressure of the liquefied fuel may fall below the vapor pressure of the liquefied fuel, potentially causing vapor lock in the liquefied fuel supply line 75 or the two-fluid injection nozzle 59, for example, and leading to unstable flow of the liquefied fuel. This is especially likely to occur when a relatively low-boiling-point liquid ammonia or similar substance is used as the liquefied fuel, rather than an oil with a relatively high boiling point. In this regard, with the above configuration, by adjusting the atomizing fluid supply pressure (Pa) of the atomizing fluid using the atomizing fluid adjustment unit 58 according to the required injection flow rate of the liquefied fuel, the injection flow rate of the liquefied fuel can be adjusted over a wide range, even when the supply pressure of the liquefied fuel is maintained above the vapor pressure of the liquefied fuel. This suppresses the occurrence of vapor lock, which is caused by the supply pressure of the liquefied fuel dropping below the vapor pressure of the liquefied fuel. Therefore, the flow of the liquefied fuel in the liquefied fuel supply path and the two-fluid injection nozzle 59 can be stabilized.

[0039] Furthermore, the following advantages can also be obtained. In other words, if the supply pressure of the atomizing fluid (Pa) is maintained at, for example, Pa2, and the supply pressure of the liquefied fuel (Pf) is adjusted, then Pf will be within the maximum variable range (Pf V Even if adjusted within the range of ≤Pf ≤ Pf1, the amount of change in flow rate is limited to the range indicated by ΔQ0, and the flow rate adjustment range of the liquefied fuel is narrow. In this respect, if the flow rate is adjusted by changing both the supply pressure of the liquefied fuel (Pf) and the supply pressure of the atomizing fluid (Pa), Pf can be adjusted within a range narrower than the maximum variable range (Pf dEven if it is adjusted within (≦Pf≦Pf1), the amount of change in the flow rate can be adjusted within the range indicated by ΔQ1, and the adjustment range of the flow rate of the liquefied fuel can be widened.

[0040] Note that the procedure for changing the flow rate from the state indicated by point J1 to the state indicated by point J4 is not limited to the above description. In other embodiments, after raising the supply pressure of the atomizing fluid from Pa3 to Pa1, the supply pressure of the liquefied fuel may be lowered from Pf1 to Pf d Even in this case, the above advantages can be enjoyed. Also, according to the required injection flow rate of the liquefied fuel, the flow rate may return to the state indicated by point J1 after changing from the state indicated by point J1 to the state indicated by point J2. Similarly, the flow rate may be changed between the state indicated by point J2 and the state indicated by point J3, or between the state indicated by point J3 and the state indicated by point J4. In the following description, the range of the required injection flow rate of the liquefied fuel corresponding to the flow rate from point J1 to point J2 and the range of the required injection flow rate of the liquefied fuel corresponding to the flow rate from point J3 to point J4 may both be described as the "first range". Also, the range of the required injection flow rate of the liquefied fuel corresponding to the flow rate from point J2 to point J3 may be described as the "second range".

[0041] In the present embodiment, in the first range of the required injection flow rate of the liquefied fuel, the controller 110 changes the supply pressure of the atomizing fluid according to the required injection flow rate of the liquefied fuel by the atomizing fluid adjustment unit 58. Also, in the second range of the required injection flow rate of the liquefied fuel, the controller 110 changes the supply pressure of the liquefied fuel according to the required injection flow rate by the liquefied fuel adjustment unit 78. According to the above configuration, since the controller 110 is suppressed from simultaneously controlling the atomizing fluid adjustment unit 58 and the liquefied fuel adjustment unit 78, the control of the injection flow rate of the liquefied fuel by the controller 110 is simplified. Also, since the control by the atomizing fluid adjustment unit 58 and the liquefied fuel adjustment unit 78 is suppressed from interfering with each other, the flow rate of the liquefied fuel to be controlled is also stabilized.

[0042] Furthermore, in this embodiment, the controller 110 adjusts the supply pressure of the liquefied fuel using the liquefied fuel adjustment unit 78 in the first range so that the supply pressure of the liquefied fuel remains constant (in the example of Figure 3, the supply pressure is Pf1 or Pf d The supply flow rate (supply amount) of liquefied fuel is controlled to maintain a constant supply pressure. In other words, the opening degree of multiple control valves 781 (see Figure 2) is controlled by the controller 110 so that the supply pressure of the liquefied fuel remains constant. According to the above configuration, when the supply pressure of the atomizing fluid is adjusted, the supply pressure of the liquefied fuel is kept constant, thus stabilizing pressure fluctuations of the liquefied fuel when it is mixed with the atomizing fluid. Therefore, the two-fluid injection nozzle 59 can stably inject the liquefied fuel.

[0043] Furthermore, in this embodiment, the first range includes a low flow rate range for the required injection flow rate and a high flow rate range with a flow rate higher than the low flow rate range. The low flow rate range is the range of the required injection flow rate corresponding to the flow rate between point J3 and point J4, and the high flow rate range is the range of the required injection flow rate corresponding to the flow rate between point J1 and point J2. The second range is a medium flow rate range that is between the low flow rate range and the high flow rate range. With the above configuration, in the medium flow rate range, which is required relatively frequently, the controller 110 changes the supply pressure of the liquefied fuel. Therefore, the flow rate of the liquefied fuel can be adjusted with greater precision in the medium flow rate range, which is required relatively frequently.

[0044] Furthermore, in this embodiment, as described above, the atomizing fluid adjustment unit 58 (see Figure 2) includes a plurality of control valves 581 with different capacities arranged in parallel. The controller 110 controls the supply pressure of the atomizing fluid and the flow rate of the liquefied fuel by controlling the opening degree of each of the plurality of control valves 581. According to the above configuration, the control valve 581 with a relatively large capacity roughly adjusts the supply pressure of the atomizing fluid, and the control valve 581 with a relatively small capacity finely adjusts the supply pressure. Therefore, even when the adjustment range of the required injection flow rate is wide, the supply pressure of the atomizing fluid can be controlled with high precision within the range of supply pressure of the atomizing fluid corresponding to that adjustment range.

[0045] Furthermore, in this embodiment, as described above, the liquefied fuel adjustment unit 78 includes a plurality of control valves 781 of different capacities arranged in parallel (see Figure 2). The controller 110 controls the supply pressure of the liquefied fuel and the flow rate of the liquefied fuel by controlling the opening degree of each of the plurality of control valves 781. According to the above configuration, the relatively large-capacity control valve 781 roughly adjusts the supply pressure of the liquefied fuel, while the relatively small-capacity control valve 781 finely adjusts the supply pressure. Therefore, the supply pressure of the liquefied fuel can be controlled with high precision within a supply pressure range that corresponds to a wide range of liquefied fuel flow rates. Furthermore, in this embodiment, high-precision control of the supply pressure of the liquefied fuel can be performed in the second range, which is frequently required.

[0046] Furthermore, in this embodiment, the storage unit 79, which is a component of the liquefied fuel supply unit 70, functions as a liquid ammonia storage unit that stores liquid ammonia. In other words, liquid ammonia is used as the liquefied fuel supplied to the two-fluid injection nozzle 59. This contributes to carbon neutrality and reduces the environmental burden.

[0047] <5. Example of Burner 51 Overview> Referring to Figure 4, an overview of the configuration of the burner 51 is illustrated. Figure 4 is a schematic configuration diagram of a burner according to one embodiment of the present disclosure. The two-fluid injection nozzle 59, a component of the burner 51, includes at least one first injection hole 591 and at least one second injection hole 592. The first injection hole 591 and the second injection hole 592 are each configured to inject a mixed fluid of liquefied fuel and atomizing fluid. In other words, liquefied fuel atomized by the atomizing fluid is injected from each of the first injection hole 591 and the second injection hole 592. In this embodiment, the supply passages for liquefied fuel and atomizing fluid are independent of the first injection port 591 and the second injection port 592. The details of these supply passages will be described below.

[0048] The supply routes for liquefied fuel are as follows, as an example: The two-fluid injection nozzle 59 includes a liquefied fuel supply passage 57 connected to the liquefied fuel supply line 75 described above. This liquefied fuel supply passage 57 has a first liquefied fuel supply passage 571 and a second liquefied fuel supply passage 572 for guiding liquefied fuel to the first injection hole 591 and the second injection hole 592, respectively. The liquefied fuel supply passage 57 is also provided with a plurality of liquefied fuel valves 157 configured to independently change the supply of liquefied fuel in the first liquefied fuel supply passage 571 and the second liquefied fuel supply passage 572, respectively. The plurality of liquefied fuel valves 157 include a first liquefied fuel on-off valve 157A provided in the first liquefied fuel supply passage 571 and a second liquefied fuel on-off valve 157B provided in the second liquefied fuel supply passage 572. The first liquefied fuel shut-off valve 157A and the second liquefied fuel shut-off valve 157B are controlled by the controller 110, allowing for independent supply of liquefied fuel to the first injection port 591 and the second injection port 592, respectively.

[0049] The supply route for the atomizing fluid is as follows, as an example: The two-fluid injection nozzle 59 includes an atomizing fluid supply passage 52 connected to the atomizing fluid supply line 55 described above. This atomizing fluid supply passage 52 has a first atomizing fluid supply passage 521 and a second atomizing fluid supply passage 522 for guiding atomizing fluid to the first injection hole 591 and the second injection hole 592, respectively. The atomizing fluid supply passage 52 is also provided with a plurality of atomizing fluid valves 152 configured to independently change the supply of atomizing fluid in the first atomizing fluid supply passage 521 and the second atomizing fluid supply passage 522. The plurality of atomizing fluid valves 152 include a first atomizing fluid valve 152A provided in the first atomizing fluid supply passage 521 and a second atomizing fluid valve 152B provided in the second atomizing fluid supply passage 522. The first atomizing fluid valve 152A and the second atomizing fluid valve 152B are controlled by the controller 110, allowing for independent supply of atomizing fluid to the first injection port 591 and the second injection port 592, respectively.

[0050] In this embodiment, the atomizing fluid supply passage 52 and the liquefied fuel supply passage 57 are located at offset positions relative to each other in the circumferential direction with respect to the axis of the two-fluid injection nozzle 59. More specifically, the first atomizing fluid supply passage 521, the second atomizing fluid supply passage 522, the first liquefied fuel supply passage 571, and the second liquefied fuel supply passage 572 are located at offset positions relative to each other in the circumferential direction (see the right-hand diagram of Figure 6). The radial distances from the axis of the two-fluid injection nozzle 59 to these four supply passages may be the same or different.

[0051] According to the above configuration, the atomizing fluid supply passage 52 and the liquefied fuel supply passage 57 are separated in the circumferential direction, thereby suppressing heat input from the atomizing fluid flowing through the atomizing fluid supply passage 52 to the liquefied fuel flowing through the liquefied fuel supply passage 57. More specifically, the liquefied fuel in the first liquefied fuel supply passage 571 and the second liquefied fuel supply passage 572 are separated in the circumferential direction from the atomizing fluid in the first atomizing fluid supply passage 521 and the second atomizing fluid supply passage 522, respectively, thereby suppressing heat input from the atomizing fluid to the liquefied fuel. Therefore, vapor lock inside the two-fluid injection nozzle 59 caused by the vaporization of the liquefied fuel can be suppressed.

[0052] Furthermore, in this embodiment, the atomizing fluid supply passage 52 and the liquefied fuel supply passage 57 shown in Figure 4 are thermally insulated. More specifically, the first liquefied fuel supply passage 571 or the second liquefied fuel supply passage 572 is thermally insulated from the first atomizing fluid supply passage 521 or the second atomizing fluid supply passage 522. Thermal insulation means that heat transfer from the atomizing fluid to the liquefied fuel is prevented in at least a portion of the axial direction of the two-fluid injection nozzle 59. In this embodiment, these four supply passages are thermally insulated from each other, and more specifically, they are thermally insulated by providing an insulating material 88 (see Figure 6). In the axial direction of the two-fluid injection nozzle 59, the length of the insulating material 88 is preferably more than half of the total length of the two-fluid injection nozzle 59, and more preferably more than three-quarters. In other embodiments, thermal insulation may be achieved by arranging a cooling air passage between the atomizing fluid supply passage 52 and the liquefied fuel supply passage 57.

[0053] According to the above configuration, the atomizing fluid flowing through the atomizing fluid supply passage 52 and the liquefied fuel flowing through the liquefied fuel supply passage 57 are thermally insulated. More specifically, the liquefied fuel in at least one of the first liquefied fuel supply passage 571 or the second liquefied fuel supply passage 572 is thermally insulated from the atomizing fluid in at least one of the first atomizing fluid supply passage 521 or the second atomizing fluid supply passage 522. This further suppresses the heat input from the atomizing fluid to the liquefied fuel, thereby further suppressing vapor lock in the two-fluid injection nozzle 59.

[0054] Furthermore, in this embodiment, the storage unit 79 described above is connected to the liquefied fuel supply line 57 via the liquefied fuel supply line 75. The storage unit 79 in this embodiment is a liquid ammonia storage unit that stores liquid ammonia as liquefied fuel. In the example in Figure 3, the first liquefied fuel supply line 571 and the second liquefied fuel supply line 572 are connected to a single storage unit 79, but two storage units 79 may be provided corresponding to these two supply lines. According to the above configuration, it is possible to contribute to carbon neutrality and reduce environmental impact.

[0055] As described above, the liquefied fuel valve 157 and the atomizing fluid valve 152 are controlled by the controller 110. More specifically, the first liquefied fuel on / off valve 157A, the second liquefied fuel on / off valve 157B, the first atomizing fluid valve 152A, and the second atomizing fluid valve 152B are each independently controlled by the controller 110. This allows for independent control of the supply of liquid ammonia and atomizing fluid at the first injection port 591 and the second injection port 592, respectively.

[0056] With the above configuration, the variable flow rate range of the liquefied fuel is expanded in both the first injection port 591 and the second injection port 592. In other words, even without setting the variable flow rate range of the liquefied fuel in each of the first liquefied fuel supply passages 571 and the second liquefied fuel supply passage 572 to an excessively wide range, a wide variable flow rate range of the liquefied fuel can be achieved for the combustion system 1 as a whole by selecting whether or not to supply liquefied fuel in each of the first liquefied fuel supply passages 571 and the second liquefied fuel supply passage 572. Therefore, a wide variable flow rate range of the liquefied fuel can be achieved in the combustion system 1 while suppressing the risk of vapor lock inside the liquefied fuel supply passage 57 and the two-fluid injection nozzle 59.

[0057] In this embodiment, when the required injection flow rate of liquefied fuel is relatively low, the liquefied fuel valve 157 and the atomizing fluid valve 152 are controlled so that only the first injection port 591 of the two injection ports 592 operates. When the required injection flow rate of liquefied fuel exceeds the upper limit of the amount of liquefied fuel injected through the first injection port 591, the liquefied fuel valve 157 and the atomizing fluid valve 152 are controlled so that the second injection port 592 operates in addition to the first injection port 591. More specifically, when the requested injection flow rate falls within the first set range of the variable flow rate range of the liquefied fuel, the controller 110 opens only the first liquefied fuel on-off valve 157A out of the first liquefied fuel on-off valve 157A and the second liquefied fuel on-off valve 157B. At this time, only the first atomizing fluid valve 152A out of the first atomizing fluid valve 152A and the second atomizing fluid valve 152B may be opened. Furthermore, if the required injection flow rate of liquefied fuel falls within a second setting range that is higher than the first setting range, the controller 110 opens the second liquefied fuel on-off valve 157B in addition to the first liquefied fuel on-off valve 157A. At this time, the second atomizing fluid valve 152B may also be opened in addition to the first atomizing fluid valve 152A.

[0058] Figure 5 is a conceptual graph showing the relationship between the liquefied fuel supply pressure and injection flow rate when the above control is performed. The horizontal axis of the graph represents the liquefied fuel supply pressure (Pf). dAs previously described using Figure 3, Pf1 is as shown. The vertical axis of the graph shows the total flow rate of liquefied fuel injected from the first injection port 591 and the second injection port 592. In this graph, the supply pressure of the atomizing fluid is Pa2. The straight line L1 shown in the graph represents the flow rate characteristics when only the first liquefied fuel shut-off valve 157A is open. Therefore, the dimension R1 shown in the graph corresponds to the first setting range. The first setting range corresponds to the second range described using Figure 3. The straight line L2 shown in the graph represents the flow rate characteristics when the second liquefied fuel valve 157B is opened in addition to the first liquefied fuel valve 157A. Therefore, dimension R2 corresponds to the second setting range.

[0059] According to the above configuration, when the required injection flow rate of liquefied fuel in the combustion system 1 is within the first set range, only the first liquefied fuel supply passage 571 is used out of the two liquefied fuel supply passages 571 and 572. Furthermore, when the required injection flow rate of liquefied fuel is within the second set range, which is higher than the first set range, both the first and second liquefied fuel supply passages 571 and 572 are used. Therefore, by selecting whether or not to supply liquefied fuel in the first and second liquefied fuel supply passages 571 and 572, a wide range of variable flow rates for the liquefied fuel can be achieved for the combustion system 1 as a whole. In other words, a wide range of variable flow rates for the liquefied fuel can be achieved in the combustion system 1 while suppressing the risk of vapor lock inside the liquefied fuel supply passage 57 and the two-fluid injection nozzle 59.

[0060] <6.2 Details of the configuration of the fluid injection nozzle 59> Refer to Figures 6 and 7 to illustrate the details of the configuration of the two-fluid injection nozzle 59. Figure 6 is a schematic diagram of a two-fluid injection nozzle according to one embodiment of the present disclosure. Figure 7 is a schematic diagram of a backplate according to one embodiment of the present disclosure. A dual-fluid injection nozzle 59 according to one embodiment of the present disclosure comprises a burner gun 560 provided with a liquefied fuel supply passage 57 and an atomizing fluid supply passage 52, a spray plate 590 provided with a first injection hole 591 and a second injection hole 592, and a back plate 550 connecting the burner gun 560 and the spray plate 590.

[0061] In the burner gun 560 of this embodiment, the liquefied fuel supply passage 57 and the atomizing fluid supply passage 52 are thermally separated by an insulating material 88. In the spray plate 590 of this embodiment, a plurality of first injection holes 591 are arranged along the circumferential direction with respect to the axis of the two-fluid injection nozzle 59. Upstream of each first injection hole 591, a mixing chamber 601 is formed where the supplied liquefied fuel and atomizing fluid are mixed. In addition, in an axial view of the two-fluid injection nozzle 59, a plurality of second injection holes 592 are arranged along the circumferential direction inside the plurality of first injection holes 591. Upstream of each second injection hole 592, a mixing chamber 602 is formed where the supplied liquefied fuel and atomizing fluid are mixed.

[0062] In this embodiment, the backplate 550 connects the first liquefied fuel supply passage 571, the first atomizing fluid supply passage 521, the second liquefied fuel supply passage 572, and the second atomizing fluid supply passage 522 to the flow paths (mixing chambers 601, 602) between the first injection hole 591 and the second injection hole 592. Specifically, the back plate 550 includes a first liquefied fuel connecting passage 501 connected to a first liquefied fuel supply passage 571, a first atomizing fluid connecting passage 511 connected to a first atomizing fluid supply passage 521, a second liquefied fuel connecting passage 502 connected to a second liquefied fuel supply passage 572, and a second atomizing fluid connecting passage 512 connected to a second atomizing fluid supply passage 522. In this embodiment, these connecting passages have an asymmetrical shape on the front end (injection side) and the base end of the back plate 550. Specifically, the base end of these connecting passages defines a cylindrical flow path parallel to or inclined with respect to the axial direction of the two-fluid injection nozzle 59, while each connecting passage on the front end defines an annular flow path in an axial view.

[0063] With the above configuration, even with a complex flow path that is asymmetrical at the front and rear ends of the backplate 550, the liquefied fuel and atomized fluid can flow smoothly and without leakage.

[0064] <7. Examples of supply methods> Referring to Figure 8, a method for supplying liquefied fuel and atomizing fluid to the two-fluid injection nozzle 59 will be described. Figure 8 is a flowchart of a method for supplying liquefied fuel and atomizing fluid according to one embodiment of the present disclosure. In the following description, "step" may be abbreviated as "S". The supply method in this example is performed by a controller 110 as an example.

[0065] First, the controller 110 acquires the combustion load of the boiler 10 (S11). Based on this, the controller 110 obtains the required injection flow rate of liquefied fuel corresponding to the combustion load. Next, the controller 110 obtains the supply pressure of the liquefied fuel and the supply pressure of the atomizing fluid according to the acquired requested injection flow rate, and controls the liquefied fuel adjustment unit 78 and the atomizing fluid adjustment unit 58 so that these supply pressures are achieved. The control in this step is as previously described with reference to Figure 3. For example, if the requested injection flow rate of the liquefied fuel falls within the first range, the controller 110 controls the atomizing fluid adjustment unit 58 to change the supply pressure of the atomizing fluid. In this embodiment, the controller 110 controls the liquefied fuel adjustment unit 78 so that the supply pressure of the liquefied fuel remains constant. With the above configuration, the flow of the liquefied fuel is stabilized.

[0066] Next, the controller 110 determines whether the requested injection flow rate of liquefied fuel obtained in connection with the execution of S11 falls within the first set range (S15). If the requested injection flow rate falls within the first set range (S15: YES), the controller 110 opens the first liquefied fuel on-off valve 157A and the first atomizing fluid valve 152A so that only the first injection hole 591 of the first injection hole 591 and the second injection hole 592 is activated (S17). On the other hand, if the requested injection flow rate falls within the second set range (S15: NO), the controller 110 opens the second liquefied fuel on-off valve 157B and the second atomizing fluid valve 152B in addition to the first liquefied fuel on-off valve 157A and the first atomizing fluid valve 152A so that the second injection hole 592 is activated in addition to the first injection hole 591 (S19). In other words, by executing either S17 or S19 depending on the required injection flow rate, the supply of liquefied fuel in the first liquefied fuel supply line 571 and the second liquefied fuel supply line 572 are independently changed. After execution of S17 or S19, the controller 110 terminates processing.

[0067] <8. Summary> The contents described in some of the embodiments above can be understood, for example, as follows:

[0068] 1) A two-fluid injection nozzle (59) according to at least one embodiment of the present disclosure is: A two-fluid injection nozzle (59) comprising at least one first injection hole (591) and at least one second injection hole (592) for injecting liquefied fuel and atomizing fluid, A first liquefied fuel supply passage (571) and a first atomizing fluid supply passage (521) for guiding the liquefied fuel and the atomizing fluid to the first injection hole (591), respectively, The present invention further includes a second liquefied fuel supply passage (572) and a second atomizing fluid supply passage (522) for guiding the liquefied fuel and the atomizing fluid, respectively, to the second injection hole (592), The first liquefied fuel supply passage (571) or the second liquefied fuel supply passage (572) is thermally insulated from the first atomizing fluid supply passage (521) or the second atomizing fluid supply passage (522).

[0069] According to the configuration described in 1) above, the liquefied fuel flowing through at least one of the first liquefied fuel supply passage (571) or the second liquefied fuel supply passage (572) is thermally insulated from the atomizing fluid flowing through at least one of the first atomizing fluid supply passage (521) or the second atomizing fluid supply passage (522). As a result, heat input from the atomizing fluid to the liquid ammonia is suppressed, thereby suppressing vapor lock inside the two-fluid injection nozzle (59). Therefore, the two-fluid injection nozzle (59) can stabilize the flow of the liquefied fuel.

[0070] 2) In some embodiments, the two-fluid injection nozzle (59) described in 1) above, The first liquefied fuel supply passage (571), the first atomizing fluid supply passage (521), the second liquefied fuel supply passage (572), and the second atomizing fluid supply passage (522) are provided at positions offset from each other in the circumferential direction with respect to the axis of the two fluid injection nozzles.

[0071] According to the configuration described in 2) above, the liquefied fuel in the first liquefied fuel supply passage (571) and the second liquefied fuel supply passage (572) are separated circumferentially from the atomizing fluid in the first atomizing fluid supply passage (521) and the second atomizing fluid supply passage (522), respectively, thereby suppressing heat input from the atomizing fluid to the liquefied fuel. Therefore, vapor lock inside the two-fluid injection nozzle (59) can be further suppressed.

[0072] 3) In some embodiments, the two-fluid injection nozzle (59) described in either 1) or 2) above, The device includes a back plate (550) that connects the flow paths between the first liquefied fuel supply passage (571), the first atomizing fluid supply passage (521), the second liquefied fuel supply passage (572), and the second atomizing fluid supply passage (522) to the first injection hole (591) and the second injection hole (592).

[0073] According to the configuration described in 3) above, even if a complex flow path is formed that is asymmetrical between the tip side (which is the injection hole side) and the base end side of the back plate (550), the liquefied fuel and atomizing fluid can be flowed smoothly without leakage.

[0074] 4) A combustion system (1) according to at least one embodiment of the present disclosure is A two-fluid injection nozzle (59) from any of the above 1) to 3), A plurality of liquefied fuel valves (157) for independently changing the supply of liquefied fuel in the first liquefied fuel supply passage (571) and the second liquefied fuel supply passage (572), The system includes a plurality of atomizing fluid valves (152) for independently changing the supply of the atomizing fluid in the first atomizing fluid supply passage (521) and the second atomizing fluid supply passage (522).

[0075] According to the configuration described in 4) above, even without setting an excessively wide variable flow rate range for the liquefied fuel in the first liquefied fuel supply passage (571) and the second liquefied fuel supply passage (572), which are the supply passages for the liquefied fuel corresponding to the first injection hole (591) and the second injection hole (592), a wide variable flow rate range for the liquefied fuel of the entire combustion system (1) can be achieved by selecting whether or not to supply liquefied fuel in each of the first liquefied fuel supply passage (571) and the second liquefied fuel supply passage (572). Therefore, a wide variable flow rate range for the liquefied fuel in the combustion system (1) can be achieved while suppressing the risk of vapor lock inside the liquefied fuel supply passage (57) or the two-fluid injection nozzle (59).

[0076] 5) In some embodiments, the combustion system (1) described in 4) above, The system includes a controller (110) for controlling the plurality of liquefied fuel valves (157), The plurality of liquefied fuel valves (157) are, The first liquefied fuel on / off valve (157A) is provided in the first liquefied fuel supply passage (571), The system includes a second liquefied fuel shut-off valve (157B) provided in the second liquefied fuel supply passage (572), The controller (110) is If the required injection flow rate of the liquefied fuel per one of the two fluid injection nozzles falls within the first setting range of the variable flow rate range of the liquefied fuel, then only the first liquefied fuel on-off valve (157A) of the first liquefied fuel on-off valve (157A) and the second liquefied fuel on-off valve (157B) is opened. If the requested injection flow rate falls within a second setting range, which is a higher flow rate than the first setting range of the variable flow rate range, the first liquefied fuel on-off valve (157A) and the second liquefied fuel on-off valve (157B) are configured to open.

[0077] According to the configuration in 5) above, when the required injection flow rate of liquefied fuel in the combustion system (1) is within the first set range, only the first liquefied fuel supply passage (571) is used out of the two liquefied fuel supply passages (572) (571 and 571). Furthermore, when the required injection flow rate of liquefied fuel is within the second set range, which is a higher flow rate than the first set range, the second liquefied fuel supply passage (572) is used in addition to the first liquefied fuel supply passage (571). Therefore, the timing at which the first liquefied fuel shut-off valve (157A) and the second liquefied fuel shut-off valve (157B) are used simultaneously is limited, making it possible to simplify the control of the first liquefied fuel shut-off valve (157A) and the second liquefied fuel shut-off valve (157B) by the controller (110).

[0078] 6) In some embodiments, the combustion system (1) described in 4) or 5) above, The system further includes at least one liquid ammonia storage section (storage section 79) connected to the first liquefied fuel supply line (571) and the second liquefied fuel supply line (572) respectively, for storing liquid ammonia as the liquefied fuel.

[0079] According to the configuration described in 6) above, it is possible to contribute to carbon neutrality and reduce environmental impact.

[0080] 7) A method for controlling the supply amount of liquefied fuel according to at least one embodiment of the present disclosure is: A method for controlling the supply amount of liquefied fuel using any of the combustion systems (1) described in 4) to 6) above, The system includes steps (S17, S19) to independently change the supply of liquefied fuel in the first liquefied fuel supply line (571) and the second liquefied fuel supply line (572).

[0081] According to the configuration described in 7) above, for the same reasons as described in 4) above, it is possible to achieve a wide variable flow rate range for liquefied fuel in the combustion system (1) while suppressing the risk of vapor lock in the liquefied fuel supply passage (57) or the two-fluid injection nozzle (59), etc. [Explanation of symbols]

[0082] 1: Combustion System 52: Atomizing fluid supply channel 57:Liquid fuel supply path 59:2 Fluid Injection Nozzle 79: Storage section 110: Controller 152: Atomizing fluid valve 157: Liquefied fuel valve 157A: First liquefied fuel shut-off valve 157B: Second liquefied fuel shut-off valve 521: First atomizing fluid supply channel 522: Second atomizing fluid supply channel 550: Backplate 571: 1st liquefied fuel supply path 572:Second liquefied fuel supply path 591: 1st injection hole 592:Second injection hole

Claims

1. A two-fluid injection nozzle comprising at least one first injection port and at least one second injection port for injecting liquefied fuel and atomizing fluid, A first liquefied fuel supply passage and a first atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid to the first injection hole, respectively, The present invention further includes a second liquefied fuel supply passage and a second atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid, respectively, to the second injection port, The liquefied fuel comprises any of liquefied natural gas, dimethyl ether, and liquid ammonia. The atomizing fluid is atomizing vapor, A two-fluid injection nozzle in which either the first liquefied fuel supply passage or the second liquefied fuel supply passage is thermally insulated from either the first atomizing fluid supply passage or the second atomizing fluid supply passage.

2. The first liquefied fuel supply passage, the first atomizing fluid supply passage, the second liquefied fuel supply passage, and the second atomizing fluid supply passage are provided at positions offset from each other in the circumferential direction with respect to the axis of the two fluid injection nozzles. The two-fluid injection nozzle according to claim 1.

3. The device comprises a back plate connecting the flow paths between the first liquefied fuel supply passage, the first atomizing fluid supply passage, the second liquefied fuel supply passage, and the second atomizing fluid supply passage, and the first injection hole and the second injection hole. The aforementioned backplate is A first liquefied fuel connecting passage connected to the first liquefied fuel supply passage, A first atomizing fluid connecting passage connected to the first atomizing fluid supply passage, A second liquefied fuel connecting passage connected to the second liquefied fuel supply passage, A second atomizing fluid connecting passage connected to the second atomizing fluid supply passage and Includes, On the injection side of the two fluid injection nozzles, the first liquefied fuel connecting passage, the first atomizing fluid connecting passage, the second liquefied fuel connecting passage, and the second atomizing fluid connecting passage are formed in an annular shape. On the injection side of the two-fluid injection nozzle, the first atomizing fluid connecting passage, the second liquefied fuel connecting passage, the second atomizing fluid connecting passage, and the first liquefied fuel connecting passage are arranged in order from the inside out. A two-fluid injection nozzle according to claim 1 or 2.

4. A two-fluid injection nozzle according to claim 1 or 2, A plurality of liquefied fuel valves for independently changing the supply of liquefied fuel in the first liquefied fuel supply passage and the second liquefied fuel supply passage, A plurality of atomizing fluid valves for independently changing the supply of the atomizing fluid in the first atomizing fluid supply passage and the second atomizing fluid supply passage, A combustion system equipped with the following features.

5. The system includes a controller for controlling the aforementioned plurality of liquefied fuel valves, The plurality of liquefied fuel valves are, A first liquefied fuel on / off valve provided in the first liquefied fuel supply passage, The system includes a second liquefied fuel on / off valve provided in the second liquefied fuel supply passage, The aforementioned controller, If the required injection flow rate of the liquefied fuel per one of the two fluid injection nozzles falls within the first setting range of the variable flow rate range of the liquefied fuel, then only the first liquefied fuel on-off valve among the first and second liquefied fuel on-off valves is opened. If the requested injection flow rate falls within a second setting range that is higher than the first setting range of the variable flow rate range, the first liquefied fuel on-off valve and the second liquefied fuel on-off valve are configured to open. The combustion system according to claim 4.

6. An atomizing fluid supply line for supplying the atomizing fluid to the two fluid injection nozzles, comprising an atomizing fluid supply line connected to an atomizing fluid supply line including the first atomizing fluid supply passage and the second atomizing fluid supply passage, An atomizing fluid adjustment unit is provided in the atomizing fluid supply line for adjusting the supply pressure of the atomizing fluid according to the required injection flow rate of the liquefied fuel, A liquefied fuel supply line for supplying the liquefied fuel to the two fluid injection nozzles, comprising a liquefied fuel supply line connected to a liquefied fuel supply line including the first liquefied fuel supply line and the second liquefied fuel supply line, A liquefied fuel adjustment unit is provided in the liquefied fuel supply line for adjusting the supply pressure of the liquefied fuel according to the required injection flow rate of the liquefied fuel. Furthermore, The aforementioned controller, In the first range, where the flow rate is lower than the first setting range of the requested injection flow rate, the atomizing fluid adjustment unit changes the supply pressure of the atomizing fluid according to the requested injection flow rate. Within the first setting range of the requested injection flow rate, the liquefied fuel adjustment unit is configured to change the supply pressure of the liquefied fuel according to the requested injection flow rate. The combustion system according to claim 5.

7. A combustion system comprising a two-fluid injection nozzle including at least one first injection port and at least one second injection port for injecting liquefied fuel and atomizing fluid, The two-fluid injection nozzles are A first liquefied fuel supply passage and a first atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid to the first injection hole, respectively, The present invention further includes a second liquefied fuel supply passage and a second atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid, respectively, to the second injection port, The liquefied fuel comprises any of liquefied natural gas, dimethyl ether, and liquid ammonia. The first liquefied fuel supply path or the second liquefied fuel supply path is thermally insulated from the first atomizing fluid supply path or the second atomizing fluid supply path. The aforementioned combustion system, A plurality of liquefied fuel valves for independently changing the supply of liquefied fuel in the first liquefied fuel supply passage and the second liquefied fuel supply passage, A plurality of atomizing fluid valves for independently changing the supply of the atomizing fluid in the first atomizing fluid supply passage and the second atomizing fluid supply passage, A controller for controlling the plurality of liquefied fuel valves and Furthermore, The plurality of liquefied fuel valves are, A first liquefied fuel on / off valve provided in the first liquefied fuel supply passage, The system includes a second liquefied fuel on / off valve provided in the second liquefied fuel supply passage, The aforementioned controller, If the required injection flow rate of the liquefied fuel per one of the two fluid injection nozzles falls within the first setting range of the variable flow rate range of the liquefied fuel, then only the first liquefied fuel on-off valve among the first and second liquefied fuel on-off valves is opened. If the requested injection flow rate falls within a second setting range that is higher than the first setting range of the variable flow rate range, the first liquefied fuel on-off valve and the second liquefied fuel on-off valve are configured to open. The aforementioned combustion system, An atomizing fluid supply line for supplying the atomizing fluid to the two fluid injection nozzles, comprising an atomizing fluid supply line connected to an atomizing fluid supply line including the first atomizing fluid supply passage and the second atomizing fluid supply passage, An atomizing fluid adjustment unit is provided in the atomizing fluid supply line for adjusting the supply pressure of the atomizing fluid according to the required injection flow rate of the liquefied fuel, A liquefied fuel supply line for supplying the liquefied fuel to the two fluid injection nozzles, comprising a liquefied fuel supply line connected to a liquefied fuel supply line including the first liquefied fuel supply line and the second liquefied fuel supply line, A liquefied fuel adjustment unit is provided in the liquefied fuel supply line for adjusting the supply pressure of the liquefied fuel according to the required injection flow rate of the liquefied fuel. Furthermore, The aforementioned controller, In a first range where the flow rate is lower than the first set range of the requested injection flow rate, the atomizing fluid adjustment unit changes the supply pressure of the atomizing fluid according to the requested injection flow rate, and the liquefied fuel adjustment unit is configured to control the supply amount of the liquefied fuel so that the supply pressure of the liquefied fuel remains constant. Within the first setting range of the requested injection flow rate, the liquefied fuel adjustment unit is configured to change the supply pressure of the liquefied fuel according to the requested injection flow rate. Combustion system.

8. A combustion system comprising a two-fluid injection nozzle including at least one first injection port and at least one second injection port for injecting liquefied fuel and atomizing fluid, The two-fluid injection nozzles are A first liquefied fuel supply passage and a first atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid to the first injection hole, respectively, The present invention further includes a second liquefied fuel supply passage and a second atomizing fluid supply passage for guiding the liquefied fuel and the atomizing fluid, respectively, to the second injection port, The liquefied fuel comprises any of liquefied natural gas, dimethyl ether, and liquid ammonia. The first liquefied fuel supply path or the second liquefied fuel supply path is thermally insulated from the first atomizing fluid supply path or the second atomizing fluid supply path. The aforementioned combustion system, A plurality of liquefied fuel valves for independently changing the supply of liquefied fuel in the first liquefied fuel supply passage and the second liquefied fuel supply passage, A plurality of atomizing fluid valves for independently changing the supply of the atomizing fluid in the first atomizing fluid supply passage and the second atomizing fluid supply passage, Furthermore, The liquefied fuel includes the liquid ammonia, A combustion system further comprising at least one liquid ammonia storage section connected to the first liquefied fuel supply line and the second liquefied fuel supply line, for storing the liquid ammonia as the liquefied fuel.

9. A method for controlling the supply amount of liquefied fuel using the combustion system described in claim 4, The method includes a step of independently changing the supply of the liquefied fuel in the first liquefied fuel supply line and the second liquefied fuel supply line. A method for controlling the supply amount of liquefied fuel.

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