TWI837782B - Atomized fluid supply unit for two-fluid injection nozzle, supply unit, combustion system, and supply method - Google Patents

Abstract

An atomizing fluid supply unit for a two-fluid spray nozzle comprises: an atomizing fluid supply line for supplying atomizing fluid to the two-fluid spray nozzle configured to atomize liquefied fuel by the atomizing fluid and spray the atomizing fluid into a furnace of a boiler; and an atomizing fluid adjustment unit provided in the atomizing fluid supply line for adjusting the supply pressure of the atomizing fluid in accordance with the required spray flow rate of the liquefied fuel.

Description

Atomizing fluid supply unit for two-fluid jet nozzle, supply unit, combustion system, and supply method

This disclosure relates to an atomizing fluid supply unit, a supply unit, a combustion system, and a supply method for a two-fluid jet nozzle.

This case claims priority based on Japanese Patent Application No. 2021-146422 filed at the Japan Patent Office on September 8, 2021, and its contents are cited here.

In the past, two-fluid jet nozzles were known that atomize liquid fuel using a spray medium such as steam and then spray it. For example, in Patent Document 1, oil is used as liquid fuel, and the oil and steam are mixed at the front end of the two-fluid jet nozzle and then sprayed.

[Prior Art Literature]

[Patent Document 1] Japan's Shō 59-007564 (Shizen 60-122623) micro-shrinking film roll

In the aforementioned patent document, if the supply pressure of the liquid fuel is reduced in order to reduce the injection amount of the liquid fuel, there is a possibility that the supply pressure will be excessively low and the temperature of the liquid fuel will be lower than the evaporation temperature. In this case, a vapor lock will occur in the liquid fuel supply path or inside the two-fluid injection nozzle, causing the flow of the liquefied fuel to become unstable. This problem is easy to occur when using a liquid fuel with a lower boiling point than oil.

The purpose of this disclosure is to provide an atomizing fluid supply unit, a supply unit, a combustion system, and a supply method for a two-fluid jet nozzle, which can stabilize the flow of liquefied fuel.

The atomizing fluid supply unit for the two-fluid spray nozzle of at least one embodiment of the present disclosure comprises: an atomizing fluid supply line for supplying the atomizing fluid to the two-fluid spray nozzle configured to atomize the liquefied fuel by the atomizing fluid and spray it into the furnace of the boiler; and an atomizing fluid adjustment unit provided in the atomizing fluid supply line for adjusting the supply pressure of the atomizing fluid corresponding to the required spray flow rate of the liquefied fuel.

The supply unit for the two-fluid jet nozzle of at least one embodiment of the present disclosure comprises: the aforementioned atomizing fluid supply unit for the two-fluid jet nozzle, the liquefied fuel supply unit, and a controller. The aforementioned liquefied fuel supply unit comprises: a liquefied fuel supply line for supplying the aforementioned liquefied fuel to the aforementioned two-fluid jet nozzle; and a liquefied fuel regulating unit provided in the aforementioned liquefied fuel supply line for corresponding to the aforementioned requirement for spraying the aforementioned liquefied fuel. The controller is configured to adjust the supply pressure of the liquefied fuel according to the injection flow rate, and the controller is configured to change the supply pressure of the atomizing fluid corresponding to the required injection flow rate by the atomizing fluid adjusting unit in the first range of the required injection flow rate before the liquefied fuel, and to change the supply pressure of the liquefied fuel corresponding to the required injection flow rate by the liquefied fuel adjusting unit in the second range of the required injection flow rate before the liquefied fuel.

The combustion system of at least one embodiment of the present disclosure comprises: a supply unit for the aforementioned two-fluid jet nozzle, and the aforementioned two-fluid jet nozzle, wherein the aforementioned two-fluid jet nozzle comprises: an atomizing fluid supply path connected to the aforementioned atomizing fluid supply line; and a liquefied fuel supply path connected to the aforementioned liquefied fuel supply line, wherein the aforementioned atomizing fluid supply path and the aforementioned liquefied fuel supply path are arranged at positions offset from each other in the circumferential direction based on the axis of the aforementioned two-fluid jet nozzle.

At least one embodiment of the present disclosure provides a supply method, which is to supply the liquefied fuel and the atomizing fluid to a two-fluid spray nozzle configured to atomize the liquefied fuel by an atomizing fluid and spray the liquefied fuel into a furnace of a boiler; the supply method comprises: a step of changing the supply pressure of the atomizing fluid in accordance with the combustion load of the boiler.

According to the present disclosure, it is possible to provide an atomizing fluid supply unit, a supply unit, a combustion system, and a supply method for a two-fluid spray nozzle, which can stabilize the flow of liquefied fuel.

1: Combustion system

10: Boiler

11: Fireplace

12: Combustion gas passage

13: Flue gas

20: Combustion device

21: Burner

22: Micro powder fuel supply pipe

22A, 22B: Micro powder fuel supply pipe

23: Air volume regulator

24: Air duct

31: Grinding machine

31A, 31B: Grinding mill (crusher)

32: Push ventilator

41: Gas catheter

42: Air preheater

43: Denitrification device

44: Dust collection device

45:Exhaust fan

46: Desulfurization device

47:Chimney

50: Combustion device

51: Burner

52: Atomizing fluid supply line

53: Cooler

54: Spray water regulating valve

55: Atomizing fluid supply line

57: Liquid fuel supply line

58: Atomizing fluid adjustment section

59: Two-fluid jet nozzle

60: Atomizing fluid supply unit

70: Liquid fuel supply unit

75: Liquid fuel supply line

76: Heater

78: Liquid fuel adjustment department

79: Storage Department

81: Adjustment valve

88: Thermal insulation material

90: Supply unit

101: Fireplace wall

102A, 102B, 102C: Superheater

103A, 103B: Reheater

104: Economizer

110: Controller

152: Atomizing fluid valve

152A: No. 1 atomizing fluid valve

152B: 2nd atomizing fluid valve

157: Liquid fuel valve

157A: No. 1 liquid fuel on/off valve

157B: Second liquid fuel on/off valve

161:Thermometer

173: Pressure gauge

175:Thermometer

176: Flow meter

182: Pressure gauge

501: 1st liquefied fuel connection line

502: Second liquefied fuel connection line

511: 1st atomizing fluid connection path

512: Second atomizing fluid connection path

521: 1st atomizing fluid supply line

522: Second atomizing fluid supply path

550: Back panel

560:Burnett Gun

571: No. 1 liquefied fuel supply line

572: Second liquefied fuel supply line

581: Control valve

590: Spray board

591: No. 1 ejection hole

592: Second ejection hole

601: Mixing room

602: Mixing chamber

752: The path back home

781: Control valve

782: Control valve

[Figure 1] is a schematic diagram of the combustion system of one embodiment of the present disclosure.

[Figure 2] is a schematic diagram of the supply unit of one embodiment of the present disclosure.

[Figure 3] is a diagram schematically showing the relationship between the flow rate of the liquefied fuel sprayed from the two-fluid spray nozzle of one embodiment of the present disclosure and the supply pressure of the liquefied fuel.

[Figure 4] is a schematic diagram of the burner of one embodiment of the present disclosure.

[Figure 5] is a diagram schematically showing the relationship between the supply pressure and injection flow rate of the liquefied fuel in one embodiment of the present disclosure.

[Figure 6] is a schematic diagram of a two-fluid jet nozzle in one embodiment of the present disclosure.

[Figure 7] is a schematic diagram of a backplane of one embodiment of the present disclosure.

[Figure 8] is a flow chart showing a method for supplying liquefied fuel and atomizing fluid in one embodiment of the present disclosure.

Hereinafter, one embodiment of the present disclosure will be described with reference to the attached drawings. Furthermore, the present invention is not limited to the embodiment, and in the case of multiple embodiments, it also includes a combination of the embodiments. In the following description, the so-called "upper" or "above" means the upper side in the vertical direction, and the so-called "lower" or "below" means the lower side in the vertical direction. The vertical direction is not strictly defined and includes errors.

Furthermore, the dimensions, materials, shapes, and relative configurations of the components described or shown in the drawings as embodiments do not limit the scope of the present disclosure, but are merely illustrative examples.

For example, expressions indicating relative or absolute configurations such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" strictly refer not only to such configurations, but also to the state of relative displacement with a tolerance or an angle or distance that can achieve the same function.

For example, "same", "equal" and "homogeneous" are expressions that indicate that things are in the same state. Strictly speaking, they not only indicate the same state, but also indicate the existence of tolerance or the difference in degree that can achieve the same function.

For example, an expression that expresses a shape such as a quadrilateral or a cylinder not only expresses the shape such as a quadrilateral or a cylinder in the strict sense of geometry, but also expresses shapes including concave and convex parts or chamfered parts within the scope that can obtain the same effect.

On the other hand, the expression "having", "including", or "having" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

In addition, the same symbols are added to the same components and the description is omitted.

<1. Overall structure of combustion system 1>

FIG1 is a schematic diagram showing the combustion system of a boiler with solid fuel and liquefied fuel as main fuel in this embodiment. Liquefied fuel is a fuel that becomes gaseous at room temperature under atmospheric pressure. The so-called room temperature in this manual is 35°C. Liquefied fuel includes, for example, petroleum (light oil or liquefied petroleum gas), liquefied natural gas, dimethyl ether and liquid ammonia. In the following description, unless otherwise specified, liquefied fuel refers to liquid ammonia.

The boiler 10 provided in the combustion system 1 of this embodiment is a boiler that can burn the powder fuel and liquefied fuel obtained by crushing solid fuel by a burner, and generate superheated steam by exchanging the heat generated by the combustion with water or steam. Biomass fuel or coal is used as the solid fuel.

The boiler 10 has a furnace 11, combustion devices 20, 50 and a combustion gas passage 12. The furnace 11 is in the shape of a hollow square tube and is arranged in 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 heat sinks connecting the heat transfer tubes to each other, so that the heat generated by the combustion of the pulverized fuel is exchanged with the water or steam flowing inside the heat transfer tubes for recovery, and the temperature rise of the furnace wall 101 is suppressed.

The combustion devices 20 and 50 are arranged in the lower area of the furnace 11. In this embodiment, the combustion device 20 is configured to spray the micronized fuel into the interior of the furnace 11. In addition, the combustion device 50 is configured to atomize the liquefied fuel by an atomizing fluid (atomizing medium) and spray it into the interior of the furnace 11. The atomizing fluid of this embodiment is atomizing steam.

The combustion device 20 has a plurality of burners 21 installed on the furnace wall 101, and the combustion device 50 has a plurality of burners 51. At the front end of each burner 21, there is a spray nozzle (not shown) configured to spray fine powder fuel into the furnace 11. In addition, at the front end of each burner 51, there is a two-fluid spray nozzle 59 configured to spray liquefied fuel into the furnace 11 by atomizing fluid (refer to Figure 4).

Burners 21 and 51 are arranged at equal intervals along the circumferential direction of the furnace 11 (for example, 4 burners are arranged at each corner of the quadrilateral furnace 11) as one group, and are arranged in multiple layers along the vertical direction. In the example of FIG. 1 , one group of burners 21 is arranged in two layers, and one group of burners 51 is arranged in four layers. In FIG. 1 , only two burners in one group are recorded for the sake of illustration, and the symbols 21 and 51 are added to each group. However, the shape of the furnace or the number of burner layers, the number of burners in one layer, the arrangement of the burners, etc. are not limited to this embodiment.

The burner 21 of the combustion device 20 is connected to a plurality of mills (crushers) 31A and 31B (hereinafter collectively referred to as "crusher 31") through a plurality of fine powder fuel supply pipes 22A and 22B (hereinafter collectively referred to as "fine powder fuel supply pipes 22"). The grinder 31 is, for example, a vertical roller grinder, which is configured to support a grinding platform (not shown in the figure) in an internal manner so as to be driven to rotate, and to support a plurality of grinding rollers (not shown in the figure) above the grinding platform so as to be able to rotate in conjunction with the rotation of the grinding platform. The solid fuel that is pulverized by the pulverizing roller and the pulverizing platform is transported to the classifier (not shown) provided in the mill 31 by the primary air (transportation gas, oxidizing gas) supplied to the mill 31. In the classifier, it is classified into fine powder fuel with a particle size below that suitable for combustion in the burner 21, and coarse powder fuel with a particle size larger than that. The fine powder fuel is supplied to the burner 21 through the fine powder fuel supply pipe 22 together with the primary air through the classifier. The coarse powder fuel that has not passed through the classifier falls onto the pulverizing platform inside the mill 31 due to its own weight and is pulverized again.

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 the two-fluid injection nozzle (hereinafter, it may be recorded as "atomizing fluid supply unit 60"), which is configured to supply atomizing fluid to the combustion device 50; and a liquefied fuel supply unit 70 for the two-fluid injection nozzle (hereinafter, it may be recorded as "liquefied fuel supply unit 70"), which is configured to supply liquefied fuel to the combustion device 50. The controller 110 obtains the required injection flow rate of the liquefied fuel in the burner 51 corresponding to the combustion load of the boiler 10. The controller 110 transmits the control command corresponding to the required injection flow rate to the supply unit 90, whereby the atomizing fluid supply unit 60 and the liquefied fuel supply unit 70 can adjust the supply amount of the atomizing fluid and the liquefied fuel respectively. The details of the structure of the supply unit 90 will be described later.

In addition, the required injection flow rate of the liquefied fuel is the required injection flow rate of the liquefied fuel of one two-fluid injection nozzle 59 (see Figure 4) of each burner 51.

An air volume regulator 23 is provided on the outside of the furnace 11 at the installation position of the burners 21 and 51, and the air volume regulator 23 is connected to one end of the air duct (air conduit) 24. A forced draft fan (FDF: Forced Draft Fan) 32 is connected to the other end of the air duct 24. The air supplied from the forced draft fan 32 is heated by the air preheater 42 installed in the air duct 24 (details are described later), and is supplied to the burner 21 as secondary air (combustion air, oxidizing gas) through the air volume regulator 23, and enters the interior of the furnace 11.

The combustion gas passage 12 is connected to the upper part of the furnace 11 in the vertical direction. In the combustion gas passage 12, as a heat exchanger for recovering the heat of the combustion gas, superheaters 102A, 102B, 102C (hereinafter collectively recorded as "superheater 102"), reheaters 103A, 103B (hereinafter collectively recorded as "reheater 103"), and economizer 104 are provided, so that heat exchange is performed between the combustion gas generated by the furnace 11 and the supply water or steam flowing inside each heat exchanger. In addition, the configuration or shape of each heat exchanger is not limited to the shape described in Figure 1.

On the downstream side of the combustion gas passage 12, a flue 13 is connected to discharge the combustion gas that has been heat recovered by the heat exchanger. An air preheater (air heater) 42 is provided between the flue 13 and the air duct 24, and heat is exchanged between the air flowing in the air duct 24 and the combustion gas flowing in the flue 13 to heat the primary air supplied to the mill 31 or the secondary air supplied to the burner 21, thereby further recovering heat from the combustion gas after heat exchange with water or steam.

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 water that has the function of reducing nitrogen oxides to the combustion gas flowing in the flue 13, and promotes the reaction between nitrogen oxides (NOX) in the combustion gas supplied with the reducing agent and the reducing agent through the catalytic action of the denitrification catalyst provided in the denitrification device 43, thereby removing and reducing nitrogen oxides in the combustion gas.

A gas duct 41 is connected to the flue 13 downstream of the air preheater 42. The gas duct 41 is provided with a dust collecting device 44 such as an electric dust collector for removing ash from the combustion gas, a desulfurization device 46 for removing sulfur oxides, or an exhaust fan (IDF: Induced Draft Fan) 45 for guiding the exhaust gas to the environmental devices. The downstream end of the gas duct 41 is connected to a chimney 47, and the combustion gas treated by the environmental device is discharged to the outside of the system as exhaust gas.

In the boiler 10, when the plurality of mills 31 are driven, the pulverized and graded fine powder fuel is supplied to the burner 21 through the fine powder fuel supply pipe 22 together with the primary air. In addition, the atomizing fluid supply unit 60 and the liquefied fuel supply unit 70 supply the atomizing fluid and the liquefied fuel to the burner 51 respectively. In addition, the secondary air heated by the air preheater 42 is supplied to the burners 21 and 51 from the air duct 24 through the air volume regulator 23.

The burner 21 blows a powder fuel mixed gas of powder fuel and primary air into the furnace 11, and blows secondary air into the furnace 11. The powder fuel mixed gas blown into the furnace 11 is ignited and reacts with the secondary air to form a flame. The burner 51 blows the secondary air and the liquefied fuel atomized by the atomizing fluid into the furnace 11. The liquefied fuel blown into the furnace 11 is vaporized into fuel gas, which reacts with the secondary air and burns.

The high-temperature combustion gas generated by the combustion of the pulverized fuel and the fuel gas rises in the furnace 11 and flows into the combustion gas passage 12.

Furthermore, the timing of blowing the liquefied fuel into the furnace 11 may be after the temperature in the furnace 11 is raised to a certain temperature by the combustion of the micro-powder fuel. For example, when the boiler 10 is started, the micro-powder fuel is exclusively burned, and then the liquefied fuel is blown into the furnace 11 to perform mixed combustion of the fuel gas vaporized from the liquefied fuel and the micro-powder fuel. Afterwards, the blowing of the micro-powder fuel is stopped, and the exclusive combustion of the liquefied fuel is also performed.

Furthermore, in this embodiment, although air is used as the oxidizing gas (primary air, secondary air), the ratio of oxygen may be higher than that of air or vice versa. By adjusting the ratio of the amount of oxygen to the amount of fuel supplied to an appropriate range, stable combustion can be achieved in the furnace 11.

The combustion gas flowing into the combustion gas passage 12 is discharged to the flue 13 after heat exchange with water or steam through the superheater 102, reheater 103, and economizer 104 arranged inside the combustion gas passage 12, and then is removed to the flue 13, and the nitrogen oxides are removed through the denitrification device 43, and the air preheater 42 is heat exchanged with the primary air and the secondary air, and then is discharged to the gas duct 41, and the ash is removed through the dust collecting device 44, and the sulfur oxides are removed through the desulfurization device 46, and then it is discharged to the outside of the system from the chimney 47. In addition, 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 arranged in the aforementioned order for the combustion gas flow.

In the aforementioned implementation form, the boiler disclosed in this disclosure is described as a boiler that uses solid fuel and liquefied fuel as fuel. As solid fuel used in the boiler, coal, biomass fuel, petroleum coke (PC: Petroleum Coke) fuel, petroleum residue, etc. are used.

Furthermore, the fuel used in the boiler combined with the liquefied fuel is not limited to solid fuels, and can also be petroleum fuels such as heavy oil, light oil, heavy oil, or liquid fuels such as factory waste liquid. In addition, gas fuels such as natural gas or various petroleum gases, and by-product gases generated in the steelmaking process, etc. can also be used.

Furthermore, it is also possible to use a mixed combustion boiler that combines these various fuels.

<2. Composition of liquefied fuel supply unit 70>

Referring to FIG. 2 , the structure of the liquefied fuel supply unit 70 as a component of the aforementioned supply unit 90 is illustrated. FIG. 2 is a schematic structural diagram of a supply unit of one embodiment of the present disclosure. In addition, in FIG. 2 , the combustion device 20 (refer to FIG. 1 ) is omitted for the convenience of viewing the diagram.

The liquefied fuel supply unit 70 includes: a storage portion 79 for storing liquefied fuel; a liquefied fuel supply line 75 for supplying the liquefied fuel stored in the storage portion 79 to the two-fluid injection nozzle 59 of the burner 51; a heater 76 provided on the liquefied fuel supply line 75; and a liquefied fuel adjustment portion 78 provided on the liquefied fuel supply line 75.

The storage part 79 stores liquid ammonia as an example of liquefied fuel. The downstream end of the liquefied fuel supply line 75 is connected to the liquefied fuel supply path 57 which is a component of the two-fluid injection nozzle 59 respectively provided in the plurality of burners 51. A return path 752 is provided on the upstream side of the liquefied fuel supply line 75 for returning a part of the supplied liquefied fuel to the storage part 79. The heater 76 is configured to heat the liquefied fuel to a certain temperature at which it does not vaporize. The heat source of the heater 76 is, for example, auxiliary steam which is a part of the steam generated in the combustion system 1. The liquefied fuel blown into the furnace 11 is easily vaporized by the heating performed by the heater 76, and the fire of the furnace 11 can be suppressed. In addition, the regulating valve 81 provided in the flow path of the auxiliary steam is adjusted according to the measurement result of the thermometer 175 used to measure the temperature of the liquefied fuel heated by the heater 76, and the heating amount of the liquefied fuel of the heater 76 is adjusted. In this example, the adjustment is performed by the controller 110.

The liquefied fuel regulating unit 78 is configured to adjust the supply pressure and flow rate of the liquefied fuel in accordance with the required injection flow rate of the liquefied fuel mentioned above.

The liquefied fuel regulating section 78 of this embodiment is a plurality of control valves 781 of different capacities arranged in parallel in the return path 752, and a control valve 782 arranged in the liquefied fuel supply line 75. The control valve 781 is, for example, a pressure regulating valve, and the control valve 782 is, for example, a flow regulating valve. In this example, the plurality of control valves 781 and the control valve 782 are controlled by the controller 110 based on the respective measurement results of the pressure gauge 173 arranged on the downstream side of the divergence point of the liquefied fuel supply line 75 and the return path 752, and the flow meter 176 arranged on the upstream side of the divergence point with the liquefied fuel supply path 57. As a more specific example, the controller 110 controls the plurality of control valves 781 and 782 respectively according to the measurement results of the pressure gauge 173 and the flow meter 176 so that the liquefied fuel of the flow rate equivalent to the required injection flow rate is supplied to the burner 51.

Furthermore, in other embodiments, the liquefied fuel supply unit 70 may not have the storage unit 79. For example, the liquefied fuel supply line 75 may be connected to a ship such as a large tanker storing liquefied fuel or a liquefied fuel manufacturing facility via a pipeline.

<3. Composition of atomizing fluid supply unit 60>

Referring to FIG. 2 , the structure of the atomizing fluid supply unit 60 as a component of the aforementioned supply unit 90 is illustrated. The atomizing fluid supply unit 60 is provided with: an atomizing fluid supply line 55 for supplying atomizing fluid to the two-fluid spray nozzle 59 of the burner 51; a cooler 53 provided on the atomizing fluid supply line 55; and an atomizing fluid adjustment section 58 provided on the atomizing fluid supply line 55. The atomizing fluid supply line 55 is connected to the atomizing fluid supply path 52 as a component of the two-fluid spray nozzle 59 provided to the plurality of burners 51.

The cooler 53 is configured to cool the atomizing fluid to a certain temperature using a cooling medium having a lower temperature than the atomizing fluid. In this embodiment, the atomizing fluid is steam, which is mixed with the spray water in the cooler 53 to cool the atomizing fluid. For example, the spray water regulating valve 54 provided in the spray water pipe is controlled by the controller 110 based on the measurement result of the thermometer 161 provided on the downstream side of the cooler 53.

The atomizing fluid adjustment section 58 is configured to adjust the supply pressure of the atomizing fluid corresponding to the required injection flow rate of the aforementioned liquefied fuel.

The atomizing fluid adjustment section 58 of this embodiment is a plurality of control valves 581 of different capacities arranged side by side on the downstream side of the cooler 53. In this example, the plurality of control valves 581 are controlled according to the measurement result of the pressure gauge 182 arranged on the downstream side of the atomizing fluid adjustment section 58. As a more specific example, the controller 110 controls the plurality of control valves 581 according to the measurement result of the pressure gauge 182 so that the atomizing fluid of the pressure corresponding to the required injection flow rate of the liquefied fuel is supplied to the burner 51.

<4. Flow control of liquefied fuel of two-fluid jet nozzle 59>

Referring to FIG. 3, the details of the flow rate control of the liquefied fuel of the two-fluid jet nozzle 59 are illustrated. FIG. 3 is a diagram schematically showing the relationship between the flow rate of the liquefied fuel sprayed from the two-fluid jet nozzle of one embodiment of the present disclosure and the supply pressure of the liquefied fuel.

The horizontal axis of the graph in FIG3 represents the flow rate (Q) of the liquefied fuel ejected from the two-fluid ejection nozzle 59.

The vertical axis of the graph represents the supply pressure (Pf) of the liquefied fuel. _Pf0 and _Pf1 on the vertical axis are respectively the lower limit burner pressure and the upper limit burner pressure of the liquefied fuel for achieving stable combustion in the burner 51. In addition, _PfV is the supply lower limit pressure for stably supplying the liquefied fuel to the burner 51, and is the value of the vapor pressure of the liquefied fuel at the temperature of the liquefied fuel heated by the heater 76.

The graph line A schematically depicted in the graph represents 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. In addition, the graph lines B and C represent 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. In addition, for the supply pressure (Pa) of the atomizing fluid, the following equation (1) is established.

Pa1>Pa2>Pa3‧‧‧(1)

Furthermore, the atomization supply pressure (Pa) does not have to be 3 pressures, but can also be controlled with more or less pressure. Moreover, the minimum pressure of Pa is zero, that is, the situation where no atomization fluid is supplied is also possible.

In this embodiment, the flow rate of the liquefied fuel sprayed from the two-fluid spray nozzle 59 is adjusted by changing the supply pressure of the liquid fuel and the supply pressure of the atomizing fluid. The following is an example of the case where the flow rate of the liquefied fuel decreases from the state shown by point J1 in the graph to the state shown by point J4 to explain the details.

First, the liquefied fuel regulator 78 maintains the supply pressure (Pf) of the liquefied fuel at _Pf1 , and the atomizing fluid regulator 58 increases the supply pressure (Pa) of the atomizing fluid from Pa3 to Pa2. As a result, the flow rate Q of the liquefied fuel is reduced from Q4 to Q3 (point J2). At this time, since the supply pressure of the liquefied fuel is maintained, the flow of the liquefied fuel is easily stabilized.

Thereafter, the atomizing fluid regulator 58 maintains the supply pressure of the atomizing fluid at Pa2, and the liquefied fuel regulator 78 reduces the supply pressure of the liquefied fuel from _Pf1 to _Pfd ( _Pfd is greater than _PfV described later). As a result, the flow rate of the liquefied fuel is reduced (point J3).

Furthermore, the liquefied fuel adjustment section 78 maintains the supply pressure of the liquefied fuel at Pf _d , and the atomizing fluid adjustment section 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 ).

The advantages of controlling the flow rate of liquefied fuel by changing both the supply pressure of liquid fuel (Pf) and the supply pressure of atomizing fluid (Pa) are as follows.

The injection amount of the liquefied fuel is related to the supply pressure of the liquefied fuel. Therefore, for example, when the flow rate of the liquefied fuel is reduced in response to the reduction in the required injection flow rate of the liquefied fuel of the two-fluid injection nozzle 59, the supply pressure (Pa) of the atomizing fluid is maintained at Pa3, for example, and only the supply pressure (Pf) of the liquefied fuel is reduced. The supply pressure (Pf) of the liquefied fuel is likely to be lower than the supply lower limit pressure Pf _V. Therefore, the supply pressure of the liquefied fuel will become lower than the vapor pressure of the liquefied fuel, causing air lock, for example, in the liquefied fuel supply line 75 or the two-fluid injection nozzle 59, and there is a risk that the flow of the liquefied fuel will become unstable. This situation is particularly likely to occur when using liquid ammonia with a relatively low boiling point rather than oil with a relatively high boiling point as a liquefied fuel.

In this regard, according to the aforementioned configuration, the atomizing fluid adjustment section 58 adjusts the supply pressure (Pa) of the atomizing fluid in accordance with the required injection flow rate of the liquefied fuel. Thus, even when the supply pressure of the liquefied fuel is maintained above the vapor pressure of the liquefied fuel, the injection flow rate of the liquefied fuel can be adjusted within a wide range. Thus, the supply pressure of the liquefied fuel can be prevented from being reduced below the vapor pressure of the liquefied fuel, thereby preventing the aforementioned air lock from occurring. Therefore, the flow of the liquefied fuel in the supply path of the liquefied fuel or the two-fluid injection nozzle 59 can be stabilized.

In addition, it also has the advantages shown below.

That is, when the supply pressure (Pa) of the atomizing fluid is maintained at Pa2, for example, and the supply pressure (Pf) of the liquefied fuel is adjusted, even if Pf is adjusted within the maximum variable range (Pf _V ≦Pf ≦Pf ₁ ), the change in flow rate is limited to the range indicated by ΔQ ₀ , and the adjustment range of the flow rate of the liquefied fuel is small. In this regard, if the flow rate is adjusted by changing both the supply pressure (Pf) of the liquefied fuel and the supply pressure (Pa) of the atomizing fluid, even if Pf is adjusted within a range narrower than the maximum variable range (Pf _d ≦Pf ≦Pf ₁ ), the change in flow rate can be adjusted within the range indicated by ΔQ ₁ , and the adjustment range of the flow rate of the liquefied fuel can be increased.

Furthermore, the change sequence of the flow rate from the state shown by point J1 to the state shown by point J4 is not limited to the above description. In other embodiments, the supply pressure of the atomizing fluid is increased from Pa3 to Pa1, and then the supply pressure of the liquefied fuel is decreased from _Pf1 to _Pfd . In this case, the above advantages can also be enjoyed.

Furthermore, corresponding to the required injection flow rate of the liquefied fuel, the flow rate may be changed from the state shown at point J1 to the state shown at point J2, and then returned to the state shown at point J1. Similarly, the flow rate may be changed between the state shown at point J2 and the state shown at point J3, or between the state shown at point J3 and the state shown at 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 are both described as "the first range". In addition, the range of the required injection flow rate of the liquefied fuel corresponding to the flow rate from point J2 to point J3 is described as "the second range".

In this 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 corresponding to the required injection flow rate of the liquefied fuel through the atomizing fluid adjustment section 58. And, 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 corresponding to the required injection flow rate through the liquefied fuel adjustment section 78.

According to the above structure, the controller 110 can avoid the situation that the atomizing fluid adjustment part 58 and the liquefied fuel adjustment part 78 are controlled at the same time, so the control of the injection flow rate of the liquefied fuel by the controller 110 is simpler. In addition, the control performed by the atomizing fluid adjustment part 58 and the liquefied fuel adjustment part 78 can be avoided from interfering with each other, so the flow rate of the controlled liquefied fuel will also be stabilized.

Furthermore, in this embodiment, the controller 110 controls the supply flow rate (supply amount) of the liquefied fuel in the first range by making the supply pressure of the liquefied fuel constant (in the example of FIG. 3 , the supply pressure becomes _Pf1 or _Pfd ). That is, the openings of the plurality of control valves 781 (see FIG. 2 ) are controlled by the controller 110 so that the supply pressure of the liquefied fuel becomes constant.

According to the above structure, when the supply pressure of the atomizing fluid is adjusted, the supply pressure of the liquefied fuel is maintained constant, so the pressure change of the liquefied fuel when the liquefied fuel and the atomizing fluid are mixed can be stabilized. Therefore, the two-fluid injection nozzle 59 can stably inject the liquefied fuel.

Furthermore, in this embodiment, the first range includes a low flow range of the required injection flow rate and a high flow range of a higher flow rate than the low flow range. The low flow range corresponds to the range of the required injection flow rate between points J3 and J4, and the high flow range corresponds to the range of the required injection flow rate between points J1 and J2. Furthermore, the second range is the middle flow range between the low flow range and the high flow range.

According to the above structure, in the variable range of the required injection flow rate of the liquefied fuel, in the middle flow range with a higher frequency of demand, the controller 110 changes the supply pressure of the liquefied fuel. Therefore, in the middle flow range with a higher frequency of demand, the flow rate of the liquefied fuel can be adjusted with higher accuracy.

Furthermore, in this embodiment, as described above, the atomizing fluid adjustment section 58 (see FIG. 2 ) is provided with a plurality of control valves 581 of different capacities arranged in parallel. Furthermore, the controller 110 controls the opening of each of the plurality of control valves 581 to control the supply pressure of the atomizing fluid, thereby controlling the flow rate of the liquefied fuel.

According to the above structure, the supply pressure of the atomizing fluid is roughly adjusted by the control valve 581 with a relatively large capacity, and the supply pressure is finely adjusted by the control valve 581 with a relatively small capacity. Therefore, even if the adjustment range of the spray flow rate is required to be a large range, the supply pressure of the atomizing fluid can be controlled with high precision within the range of the supply pressure of the atomizing fluid corresponding to the adjustment range.

Furthermore, in this embodiment, as described above, the liquefied fuel regulating section 78 has a plurality of control valves 781 of different capacities arranged in parallel (see FIG. 2 ). Furthermore, the controller 110 controls the opening of each of the plurality of control valves 781 to control the supply pressure of the liquefied fuel and thereby control the flow rate of the liquefied fuel.

According to the above structure, the supply pressure of the liquefied fuel is roughly adjusted by the control valve 781 with a relatively large capacity, and the supply pressure is finely adjusted by the control valve 781 with a relatively small capacity. Therefore, the supply pressure of the liquefied fuel can be controlled with high precision within the supply pressure range of the liquefied fuel corresponding to the flow range of the liquefied fuel in a wide range. Moreover, in this embodiment, the supply pressure of the liquefied fuel can be controlled with high precision in the second range with a high demand frequency.

Furthermore, in this embodiment, the storage portion 79 as a component of the liquefied fuel supply unit 70 functions as a liquid ammonia storage portion for storing liquid ammonia. That is, liquid ammonia is used as the liquefied fuel supplied to the two-fluid injection nozzle 59. This can promote carbon neutrality and reduce environmental burden.

<5. Example of the outline of the burner 51>

Referring to FIG. 4 , the outline of the structure of the burner 51 is illustrated. FIG. 4 is a schematic structural diagram of a burner of one embodiment of the present disclosure. The two-fluid jet nozzle 59 as a component of the burner 51 includes: at least one first jet hole 591 and at least one second jet hole 592. The first jet hole 591 and the second jet hole 592 are configured to respectively jet a mixed fluid of liquefied fuel and atomized fluid. In other words, the first jet hole 591 and the second jet hole 592 each jet a liquefied fuel atomized by the atomized fluid.

In this embodiment, the supply paths for supplying liquefied fuel and atomized fluid are independent of each other in the first injection hole 591 and the second injection hole 592. The supply paths are described in detail below.

The supply line of liquefied fuel is as follows as an example.

The two-fluid injection nozzle 59 includes a liquefied fuel supply path 57 connected to the aforementioned liquefied fuel supply line 75. The liquefied fuel supply path 57 includes a first liquefied fuel supply path 571 and a second liquefied fuel supply path 572 for guiding the liquefied fuel to the first injection hole 591 and the second injection hole 592, respectively. In addition, the liquefied fuel supply path 57 is provided with a plurality of liquefied fuel valves 157 configured to independently change the supply of liquefied fuel to the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572. Furthermore, the plurality of liquefied fuel valves 157 include a first liquefied fuel on-off valve 157A provided in the first liquefied fuel supply path 571, and a second liquefied fuel on-off valve 157B provided in the second liquefied fuel supply path 572. The first liquefied fuel on-off valve 157A and the second liquefied fuel on-off valve 157B are controlled by the controller 110, thereby independently supplying liquefied fuel to the first injection hole 591 and the second injection hole 592.

The supply path of the atomizing fluid is as follows as an example.

The two-fluid injection nozzle 59 includes an atomizing fluid supply path 52 connected to the aforementioned atomizing fluid supply line 55. The atomizing fluid supply path 52 has a first atomizing fluid supply path 521 and a second atomizing fluid supply path 522 for guiding the liquefied fuel to the first injection hole 591 and the second injection hole 592, respectively. In addition, the atomizing fluid supply path 52 is provided with a plurality of atomizing fluid valves 152, which are configured to independently change the supply of the atomizing fluid to the first atomizing fluid supply path 521 and the second atomizing fluid supply path 522. Furthermore, the plurality of atomizing fluid valves 152 include a first atomizing fluid valve 152A disposed in the first atomizing fluid supply path 521, and a second atomizing fluid valve 152B disposed in the second atomizing fluid supply path 522. The first atomizing fluid valve 152A and the second atomizing fluid valve 152B are controlled by the controller 110, thereby independently supplying the atomizing fluid to the first ejection hole 591 and the second ejection hole 592.

In this embodiment, the atomizing fluid supply path 52 and the liquefied fuel supply path 57 are arranged at positions offset from each other in the circumferential direction based on the axis of the two-fluid injection nozzle 59. More specifically, the first atomizing fluid supply path 521, the second atomizing fluid supply path 522, the first liquefied fuel supply path 571, and the second liquefied fuel supply path 572 are arranged at positions offset from each other in the circumferential direction (refer to the right side of Figure 6). The radial distance from the axis of the two-fluid injection nozzle 59 to the four supply paths may be the same or different.

According to the above-mentioned structure, the atomizing fluid supply path 52 and the liquefied fuel supply path 57 are separated from each other in the circumferential direction, thereby suppressing the heat input of the atomizing fluid flowing in the atomizing fluid supply path 52 to the liquefied fuel flowing in the liquefied fuel supply path 57. More specifically, the liquefied fuel in each of the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572 is separated from the atomizing fluid in each of the first atomizing fluid supply path 521 and the second atomizing fluid supply path 522 in the circumferential direction, thereby suppressing the heat input of the atomizing fluid to the liquefied fuel. Therefore, the air lock inside the two-fluid injection nozzle 59 caused by the vaporization of the liquefied fuel can be suppressed.

Furthermore, in the present embodiment, the atomizing fluid supply path 52 and the liquefied fuel supply path 57 shown in FIG. 4 are thermally insulated. More specifically, the first liquefied fuel supply path 571 or the second liquefied fuel supply path 572 is thermally insulated from the first atomizing fluid supply path 521 or the second atomizing fluid supply path 522. The so-called thermal insulation means that the heat transfer from the atomizing fluid to the liquefied fuel is blocked in at least a portion of the axial direction of the two-fluid spray nozzle 59. In the present embodiment, the four supply paths are thermally insulated from each other, and more specifically, they are thermally insulated by providing a heat insulating material 88 (see FIG. 6). In the axial direction of the two-fluid jet nozzle 59, the length of the heat insulating material 88 is preferably more than half of the total length of the two-fluid jet nozzle 59, and more preferably more than three-quarters.

Furthermore, in other embodiments, thermal insulation may be achieved by configuring a cooling air flow path between the atomizing fluid supply path 52 and the liquefied fuel supply path 57.

According to the above structure, the atomizing fluid flowing in the atomizing fluid supply path 52 and the liquefied fuel flowing in the liquefied fuel supply path 57 are thermally insulated. More specifically, the liquefied fuel in at least one of the first liquefied fuel supply path 571 or the second liquefied fuel supply path 572 and the atomizing fluid in at least one of the first atomizing fluid supply path 521 or the second atomizing fluid supply path 522 are thermally insulated. Thus, since the heat input from the atomizing fluid to the liquefied fuel is further suppressed, the air lock of the two-fluid injection nozzle 59 can be further suppressed.

Furthermore, in this embodiment, the aforementioned storage section 79 is connected to the liquefied fuel supply path 57 via the liquefied fuel supply line 75. The storage section 79 of this embodiment is a liquid ammonia storage section for storing liquid ammonia as a liquefied fuel. In the example of FIG. 3 , the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572 are connected to a single storage section 79, and two storage sections 79 corresponding to the two supply paths may also be provided.

Based on the above structure, it can promote carbon neutrality and reduce environmental burden.

As mentioned 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 independently controlled by the controller 110. Thus, the control of the supply of liquid ammonia and atomizing fluid is independently controlled at the first injection hole 591 and the second injection hole 592.

According to the above-mentioned structure, the variable flow range of the liquefied fuel is expanded in the first injection hole 591 and the second injection hole 592. That is, even if the variable flow range of the liquefied fuel of each of the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572 is not set too large, the variable flow range of the liquefied fuel of the combustion system 1 can be realized in a wide range by selecting the supply of the liquefied fuel of each of the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572. Therefore, the risk of air lock inside the liquefied fuel supply path 57 or the two-fluid injection nozzle 59 can be suppressed, and a wide variable flow range of the liquefied fuel in the combustion system 1 can be realized.

In this embodiment, when the required injection flow rate of the liquefied fuel is relatively small, the liquefied fuel valve 157 and the atomizing fluid valve 152 are controlled by actuating only the first injection hole 591 among the first injection hole 591 and the second injection hole 592. Furthermore, when the required injection flow rate of the liquefied fuel exceeds the injection amount upper limit of the liquefied fuel of the first injection hole 591, the liquefied fuel valve 157 and the atomizing fluid valve 152 are controlled by actuating the second injection hole 592 in addition to the first injection hole 591.

More specifically, when the required injection flow rate is included in the first setting range of the variable flow range of the liquefied fuel, the controller 110 only opens the first liquefied fuel on-off valve 157A among 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 among the first atomizing fluid valve 152A and the second atomizing fluid valve 152B may be opened.

Furthermore, when the required injection flow rate of the liquefied fuel is included in the second setting range having a higher flow rate than the first setting range, the controller 110 opens the second liquefied fuel opening and closing valve 157B in addition to the first liquefied fuel opening and closing valve 157A. At this time, the second atomizing fluid valve 152B may be opened in addition to the first atomizing fluid valve 152A.

FIG5 is a diagram schematically showing the relationship between the supply pressure of the liquefied fuel and the injection flow rate when the above control is performed. The horizontal axis of the diagram represents the supply pressure of the liquefied fuel (Pf), and _Pfd and _Pf1 are as described in FIG3. The vertical axis of the diagram represents the total flow rate of the liquefied fuel injected from the first injection hole 591 and the second injection hole 592. In the diagram, the supply pressure of the atomizing fluid is Pa2.

The straight line L1 shown in the graph represents the flow characteristics when only the first liquefied fuel on-off valve 157A is opened. Therefore, the dimension R1 shown in the graph is equivalent to the first setting range. In addition, the first setting range is equivalent to the second range described in Figure 3.

The straight line L2 shown in the graph represents the flow characteristics when the second liquefied fuel on-off valve 157B is opened in addition to the first liquefied fuel on-off valve 157A. Therefore, the dimension R2 is equivalent to the second setting range.

According to the above configuration, when the required injection flow rate of the liquefied fuel of the combustion system 1 falls within the first setting range, only the first liquefied fuel supply path 571 is used between the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572. Furthermore, when the required injection flow rate of the liquefied fuel falls within the second setting range of a higher flow rate than the first setting range, in addition to the first liquefied fuel supply path 571, the second liquefied fuel supply path 572 is also used. Therefore, by selecting whether the liquefied fuel is supplied to each of the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572, a wide range of variable flow rates of the liquefied fuel of the combustion system 1 as a whole can be achieved. That is, it is possible to suppress the risk of air lock inside the liquefied fuel supply path 57 or the two-fluid injection nozzle 59, and to realize a wide variable flow range of the liquefied fuel in the combustion system 1.

<6. Details of the structure of the two-fluid jet nozzle 59>

Referring to Figures 6 and 7, the details of the structure of the two-fluid jet nozzle 59 are illustrated. Figure 6 is a schematic diagram of the two-fluid jet nozzle of one embodiment of the present disclosure. Figure 7 is a schematic diagram of the back plate of one embodiment of the present disclosure.

The two-fluid spray nozzle 59 of one embodiment of the present disclosure comprises: a burner gun 560 provided with a liquefied fuel supply path 57 and an atomizing fluid supply path 52; a spray plate 590 provided with a first spray hole 591 and a second spray hole 592; and a back plate 550 connecting the burner gun 560 and the spray plate 590.

In the burner gun 560 of this embodiment, the liquefied fuel supply path 57 and the atomizing fluid supply path 52 are thermally isolated by the heat insulating material 88.

In the spray plate 590 of this embodiment, a plurality of first spray holes 591 are arranged along the circumferential direction based on the axis of the two-fluid spray nozzle 59. A mixing chamber 601 is formed on the upstream side of each first spray hole 591 to mix the supplied liquefied fuel with the atomizing fluid. In addition, a plurality of second spray holes 592 are arranged along the circumferential direction at the inner side of the two-fluid spray nozzle 59 than the plurality of first spray holes 591 when viewed in the axial direction. A mixing chamber 602 is formed on the upstream side of each second spray hole 592 to mix the supplied liquefied fuel with the atomizing fluid.

The back plate 550 of this embodiment is connected to the first liquefied fuel supply path 571, the first atomized fluid supply path 521, the second liquefied fuel supply path 572, the second atomized fluid supply path 522, the first injection hole 591 and the second injection hole 592 (mixing chambers 601, 602).

Specifically, the back plate 550 includes: a first liquefied fuel connection path 501 connected to the first liquefied fuel supply path 571, a first atomizing fluid connection path 511 connected to the first atomizing fluid supply path 521, a second liquefied fuel connection path 502 connected to the second liquefied fuel supply path 572, and a second atomizing fluid connection path 512 connected to the second atomizing fluid supply path 522. In this embodiment, the connection paths are asymmetrically shaped at the front end side (injection side) and the base end side of the back plate 550. Specifically, the base end side of the connecting paths divides a cylindrical flow path parallel to or inclined to the axis direction of the two-fluid jet nozzle 59, and each connecting path on the front end side divides a ring-shaped flow path when viewed in the axial direction.

According to the above structure, even if the front and rear ends of the back plate 550 are asymmetrical and complex flow paths, the liquefied fuel and atomized fluid can flow smoothly and without leakage.

<7. Examples of supply methods>

Referring to FIG. 8 , a method for supplying liquefied fuel and atomizing fluid to the two-fluid injection nozzle 59 is described. FIG. 8 is a flow chart showing a method for supplying liquefied fuel and atomizing fluid in one embodiment of the present disclosure. In the following description, "step" is omitted as "S". The supply method in this example is executed by the controller 110 as an example.

First, the controller 110 obtains the combustion load of the boiler 10 (S11). Thus, the controller 110 obtains the required injection flow rate of the 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 corresponding to the obtained required injection flow rate, and controls the liquefied fuel adjustment section 78 and the atomizing fluid adjustment section 58 in a manner to realize the supply pressures. The control of this step is as described in FIG. 3. For example, when the required injection flow rate of the liquefied fuel is included in the first range, the controller 110 controls the atomizing fluid adjustment section 58 to change the supply pressure of the atomizing fluid.

In this embodiment, at this time, the controller 110 controls the liquefied fuel regulating unit 78 in such a way that the supply pressure of the liquefied fuel becomes constant. According to the above-mentioned structure, the flow of the liquefied fuel is stabilized.

Next, the controller 110 determines whether the required injection flow rate of the liquefied fuel obtained by executing S11 is included in the first setting range (S15). In the case where the required injection flow rate is included in the first setting range (S15: YES), the controller 110 opens the first liquefied fuel on-off valve 157A and the first atomizing fluid valve 152A in such a manner that only the first injection hole 591 of the first injection hole 591 and the second injection hole 592 is actuated (S17). On the other hand, when the required injection flow rate is included in the second setting range (S15: NO), the controller 110 activates the second injection hole 592 in addition to the first injection hole 591, and 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 (S19).

That is, by executing either S17 or S19 corresponding to the required injection flow rate, the supply of liquefied fuel to the first liquefied fuel supply path 571 and the second liquefied fuel supply path 572 is changed independently.

After executing S17 or S19, the controller 110 ends the processing.

<8. Conclusion>

The contents described in the aforementioned implementation forms are summarized as follows.

1) The atomizing fluid supply unit (60) for the two-fluid spray nozzle of at least one embodiment of the present disclosure comprises: an atomizing fluid supply line (55) for supplying the atomizing fluid to the two-fluid spray nozzle (59) configured to atomize the liquefied fuel by the atomizing fluid and spray the atomized fluid into the furnace (11) of the boiler (10); and an atomizing fluid adjustment unit (58) provided on the atomizing fluid supply line (55) for adjusting the supply pressure of the atomizing fluid in accordance with the required spray flow rate of the liquefied fuel.

The amount of liquefied fuel injected by the two-fluid injection nozzle is related to the supply pressure of the liquefied fuel and the supply pressure of the atomizing fluid. Therefore, if, for example, the supply pressure of the liquefied fuel is reduced in response to a reduction in the required injection flow rate of the liquefied fuel of the two-fluid injection nozzle (59), the supply pressure of the liquefied fuel will become lower than the vapor pressure, which may cause, for example, air lock in the liquefied fuel supply path (57) or the two-fluid injection nozzle (59), thereby making the flow of the liquefied fuel unstable. In this regard, according to the structure of 1) above, the atomizing fluid supply pressure is adjusted by the atomizing fluid adjustment section (58) in accordance with the required injection flow rate of the liquefied fuel, thereby, even if the supply pressure of the liquefied fuel is maintained above the vapor pressure of the liquefied fuel, the injection flow rate of the liquefied fuel can be adjusted within a wide range. In this way, the supply pressure of the liquefied fuel can be suppressed from decreasing below the vapor pressure of the liquefied fuel, thereby preventing the aforementioned air lock from occurring. Therefore, for example, an atomizing fluid supply unit (60) for a two-fluid injection nozzle that can stabilize the flow of the liquefied fuel in the liquefied fuel supply path (57) or the two-fluid injection nozzle (59) can be realized.

2) In each embodiment, the atomizing fluid supply unit (60) for the two-fluid spray nozzle described in 1) above is: the atomizing fluid adjustment section (58) is provided with a plurality of control valves (581) of different capacities arranged in parallel.

According to the structure of 2) above, the supply pressure of the atomizing fluid is roughly adjusted by the control valve (581) with a relatively large capacity, and the atomizing fluid is finely adjusted by the control valve (581) with a relatively small capacity. Therefore, the supply pressure of the atomizing fluid can be controlled with high precision within the supply pressure range of the atomizing fluid corresponding to a wide range of the flow rate of the liquefied fuel.

3) A supply unit (90) for a two-fluid jet nozzle of at least one embodiment of the present disclosure comprises: an atomizing fluid supply unit (60) for a two-fluid jet nozzle as described in 1) or 2); a liquefied fuel supply path (57); and a controller (110), wherein the liquefied fuel supply path (57) comprises: a liquefied fuel valve (157) for supplying the liquefied fuel to the two-fluid jet nozzle (59); and a liquefied fuel regulating section (78) disposed on the liquefied fuel valve (157) for regulating the liquefied fuel. The supply pressure of the liquefied fuel should be adjusted according to the required injection flow rate of the liquefied fuel. The controller (110) is configured such that: within the first range of the required injection flow rate of the liquefied fuel, the supply pressure of the atomizing fluid is changed corresponding to the required injection flow rate by the atomizing fluid adjustment unit (58); within the second range of the required injection flow rate of the liquefied fuel, the supply pressure of the liquefied fuel is changed corresponding to the required injection flow rate by the liquefied fuel adjustment unit (78).

According to the structure of 3) above, it is possible to avoid the controller (110) from controlling the atomizing fluid adjustment section (58) and the liquefied fuel adjustment section (78) at the same time, so that the control of the injection flow rate of the liquefied fuel by the controller (110) is simpler. In addition, it is possible to avoid the control performed by the atomizing fluid adjustment section (58) and the liquefied fuel adjustment section (78) from interfering with each other, so the flow rate of the controlled liquefied fuel will also be stabilized.

4) In each embodiment, the supply unit (90) for the two-fluid jet nozzle described in 3) is: the controller (110) is configured to control the supply amount (supply flow rate) of the liquefied fuel in the first range, further by the liquefied fuel adjustment unit (78), so that the supply pressure of the liquefied fuel is constant.

According to the structure of 4) above, when the supply pressure of the atomizing fluid is adjusted, the supply pressure of the liquefied fuel is maintained constant, so that the pressure change of the liquefied fuel when the liquefied fuel and the atomizing fluid are mixed can be stabilized. Therefore, the two-fluid injection nozzle (59) can stably inject the liquefied fuel.

5) In each embodiment, the supply unit (90) for the two-fluid jet nozzle described in 4) is: the first range includes the low flow range of the required jet flow rate and the high flow range with a higher flow rate than the low flow range, and the second range is the flow range between the low flow range and the high flow range.

According to the structure of 5) above, in the variable range of the required injection flow rate of the liquefied fuel, in the middle flow rate range with a higher frequency of demand, the controller (110) changes the supply pressure of the liquefied fuel. Therefore, in the middle flow rate range with a higher frequency of demand, the flow rate of the liquefied fuel can be adjusted with higher accuracy.

6) In each embodiment, the supply unit (90) for the two-fluid jet nozzle described in any one of the above 4) or 5) is: the above liquefied fuel adjustment section (78) is equipped with a plurality of control valves (781) of different capacities arranged in parallel.

According to the structure of 6) above, the liquefied fuel is roughly adjusted by the control valve (781) with a relatively large capacity, and the liquefied fuel is finely adjusted by the control valve (781) with a relatively small capacity. Therefore, the liquefied fuel supply pressure can be controlled with high precision within the liquefied fuel supply pressure range corresponding to a wide range of liquefied fuel flow rates.

7) In each embodiment, the supply unit (90) for the two-fluid jet nozzle described in any one of the above 3) to 6) is: the above liquefied fuel supply path (57), further comprising: a liquid ammonia storage part (storage part 79), which is connected to the above liquefied fuel valve (157) and stores liquid ammonia as the above liquefied fuel.

According to the composition of 7) above, it can promote carbon neutrality and reduce the environmental burden.

8) The combustion system (1) of at least one embodiment of the present disclosure comprises: a supply unit (90) for a two-fluid jet nozzle as described in any one of 4) to 7); and the two-fluid jet nozzle (59), wherein the two-fluid jet nozzle (59) comprises: an atomizing fluid supply path (52) connected to the atomizing fluid supply line (55); and a liquefied fuel supply path (57) connected to the liquefied fuel valve (157), wherein the atomizing fluid supply path (52) and the liquefied fuel supply path (57) are arranged at positions offset from each other in a circumferential direction based on the axis of the two-fluid jet nozzle (59).

According to the structure of 8) above, the atomizing fluid supply path (52) and the liquefied fuel supply path (57) are separated from each other in the circumferential direction, thereby suppressing the heat input to the liquefied fuel flowing in the liquefied fuel supply path (57). In this way, the air lock inside the two-fluid injection nozzle (59) can be suppressed.

9) In each embodiment, the combustion system (1) described in 8) above is: the aforementioned two-fluid injection nozzle (59) is used to thermally insulate the aforementioned atomizing fluid supply path (52) from the aforementioned liquefied fuel supply path (57).

According to the structure of 9) above, the atomizing fluid flowing in the atomizing fluid supply path (52) and the liquefied fuel flowing in the liquefied fuel supply path (57) are thermally insulated. As a result, the heat input from the atomizing fluid to the liquefied fuel is further suppressed, so the air lock of the two-fluid injection nozzle (59) can be further suppressed.

10) The supply method of at least one embodiment of the present disclosure is: a supply method for supplying the liquefied fuel and the atomizing fluid to a two-fluid spray nozzle (59) configured to atomize the liquefied fuel by an atomizing fluid and spray the liquefied fuel into a furnace (11) of a boiler (10); the supply method comprises: a step (S13) of changing the supply pressure of the atomizing fluid in accordance with the combustion load of the boiler (10).

According to the structure of 10) above, for the same reason as 1) above, a supply method capable of stabilizing the flow of liquefied fuel can be realized.

11) In each embodiment, the supply method described in 10) is: the step (S13) is to control the supply amount of the liquefied fuel by changing the supply pressure of the atomizing fluid while keeping the supply pressure of the liquefied fuel constant.

According to the structure of 11) above, the flow of liquefied fuel can be further stabilized when the supply pressure of the atomizing fluid changes.

10: Boiler

11: Fireplace

23: Air volume regulator

50: Combustion device

51: Burner

52: Atomizing fluid supply line

53: Cooler

54: Spray water regulating valve

55: Atomizing fluid supply line

57: Liquid fuel supply line

58: Atomizing fluid adjustment section

59: Two-fluid jet nozzle

60: Atomizing fluid supply unit

70: Liquid fuel supply unit

75: Liquid fuel supply line

76: Heater

78: Liquid fuel adjustment department

79: Storage Department

81: Adjustment valve

90: Supply unit

110: Controller

152: Atomizing fluid valve

157: Liquid fuel valve

161:Thermometer

173: Pressure gauge

175:Thermometer

176: Flow meter

182: Pressure gauge

581: Control valve

752: The path back home

781: Control valve

782: Control valve

Claims (11)

An atomizing fluid supply unit for a two-fluid spray nozzle comprises: an atomizing fluid supply line for supplying the atomizing fluid to the two-fluid spray nozzle configured to atomize liquefied fuel by the atomizing fluid and spray the atomized fluid into a furnace of a boiler; and an atomizing fluid adjustment unit provided in the atomizing fluid supply line for adjusting the supply pressure of the atomizing fluid in accordance with the required spray flow rate of the liquefied fuel. The atomizing fluid supply unit for the two-fluid spray nozzle as described in claim 1, wherein the atomizing fluid adjustment section is provided with a plurality of control valves of different capacities arranged in parallel. A supply unit for a two-fluid jet nozzle comprises: an atomizing fluid supply unit for the two-fluid jet nozzle as described in claim 1 or 2; a liquefied fuel supply unit, and a controller, wherein the liquefied fuel supply unit comprises: a liquefied fuel supply line for supplying the liquefied fuel to the two-fluid jet nozzle; and a liquefied fuel adjustment unit provided in the liquefied fuel supply line for adjusting the flow rate of the liquefied fuel to correspond to the required flow rate of the liquefied fuel. , adjusting the supply pressure of the aforementioned liquefied fuel, the aforementioned controller is configured as follows: in the first range of the required injection flow rate before the aforementioned liquefied fuel, the supply pressure of the aforementioned atomizing fluid is changed corresponding to the aforementioned required injection flow rate by the aforementioned atomizing fluid adjustment unit, and in the second range of the required injection flow rate before the aforementioned liquefied fuel, the supply pressure of the aforementioned liquefied fuel is changed corresponding to the aforementioned required injection flow rate by the aforementioned liquefied fuel adjustment unit. The supply unit for the two-fluid jet nozzle as described in claim 3, wherein the controller is configured to control the supply amount of the liquefied fuel in the first range by further using the liquefied fuel adjustment unit to make the supply pressure of the liquefied fuel constant. A supply unit for a two-fluid jet nozzle as described in claim 4, wherein the first range includes a low flow range of the required jet flow rate and a high flow range with a higher flow rate than the low flow range, and the second range is a flow range between the low flow range and the high flow range. A supply unit for a two-fluid jet nozzle as described in claim 4, wherein the aforementioned liquefied fuel regulating section is provided with a plurality of control valves of different capacities arranged in parallel. The supply unit for the two-fluid jet nozzle as described in claim 3, wherein the aforementioned liquefied fuel supply unit further comprises: a liquid ammonia storage unit connected to the aforementioned liquefied fuel supply line to store liquid ammonia as the aforementioned liquefied fuel. A combustion system comprises: a supply unit for a two-fluid jet nozzle as described in any one of claims 4 to 7; and the two-fluid jet nozzle, wherein the two-fluid jet nozzle comprises: an atomizing fluid supply path connected to the atomizing fluid supply line; and a liquefied fuel supply path connected to the liquefied fuel supply line, wherein the atomizing fluid supply path and the liquefied fuel supply path are arranged at positions offset from each other in a circumferential direction based on the axis of the two-fluid jet nozzle. The combustion system as described in claim 8, wherein the aforementioned two-fluid injection nozzle provides thermal insulation between the aforementioned atomizing fluid supply path and the aforementioned liquefied fuel supply path. A supply method is to supply the liquefied fuel and the atomizing fluid to a two-fluid spray nozzle configured to atomize the liquefied fuel by an atomizing fluid and spray the liquefied fuel into a furnace of a boiler; the supply method comprises: a step of changing the supply pressure of the atomizing fluid in accordance with the combustion load of the boiler. The supply method as described in claim 10, wherein the aforementioned step is to control the supply amount of the aforementioned liquefied fuel in such a manner that the supply pressure of the aforementioned atomizing fluid is changed while the supply pressure of the aforementioned liquefied fuel is kept constant.

Images