TW202340650A - Ammonia combustion burner, boiler, and boiler operation method - Google Patents

Abstract

This ammonia combustion burner, according to at least one embodiment of the present disclosure, is for combusting ammonia fuel using a boiler, and comprises: a combustion air nozzle for jetting combustion air; a first ammonia injection nozzle that is disposed on the inside of the combustion air nozzle and that is for injecting ammonia fuel on the inside of the combustion air nozzle; and a flame holder disposed on the downstream side from the first ammonia injection nozzle. The combustion air nozzle is configured to jet: a partial premixed fuel consisting of a portion of the combustion air and the ammonia fuel injected from the first ammonia injection nozzle; and the remainder of the combustion air.

Description

Ammonia combustion burners, boilers and boiler operating methods

The present invention relates to an ammonia combustion burner, a boiler and an operating method of the boiler. This case claims priority based on Special Application No. 2021-209694 filed with the Japan Patent Office on December 23, 2021, the contents of which are cited here.

There is known a boiler in which ammonia is supplied to the furnace as fuel. For example, the boiler disclosed in Patent Document 1 performs ammonia mixed combustion in which ammonia and coal are burned together in the furnace. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2020-41748

[Problem to be solved by the invention]

When a burner burns ammonia, the amount of NOx produced is more easily affected by the local air ratio at the contact surface between the fuel and combustion air at the combustion site than when burning other fuels. Therefore, in order to suppress the amount of NOx generated, it is important to control the local air ratio at the contact surface between ammonia and combustion air in the combustion site.

In view of the above, at least one embodiment of the present invention aims to suppress the amount of NOx produced by an ammonia combustion burner. [Technical means to solve problems]

(1) An ammonia combustion burner according to at least one embodiment of the present invention, It is an ammonia combustion burner used to burn ammonia fuel in boilers. It has: Combustion air nozzle, which is used to spray combustion air; a first ammonia injection nozzle arranged inside the combustion air nozzle for injecting the ammonia fuel into the combustion air nozzle; and a flame retainer arranged downstream of the first ammonia injection nozzle, The combustion air nozzle is configured to inject a portion of the combustion air, a premixed fuel portion of the ammonia fuel previously injected from the first ammonia injection nozzle, and a remaining portion of the combustion air.

(2) The boiler of at least one embodiment of the present invention has: A stove containing a stove wall; and The ammonia combustion burner of the structure (1) above is provided on the furnace wall.

(3) The boiler of at least one embodiment of the present invention has: A stove containing a stove wall; The ammonia combustion burner with the structure of the above (1) is installed on the aforementioned furnace wall; and Other fuel burners are provided on the furnace wall at a different position from the ammonia combustion burner to burn fuels other than the ammonia fuel.

(4) The boiler of at least one embodiment of the present invention has: A stove containing a stove wall; The ammonia combustion burner with the structure of (1) above is located on the wall of the aforementioned furnace; A fire detection sensor that detects fire inside the aforementioned combustion air nozzle; and a control device that controls the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor, The aforementioned control device has: an injection amount calculation unit that calculates the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor; and The adjustment unit adjusts the injection amount to become the injection amount calculated by the injection amount calculation unit.

(5) The boiler of at least one embodiment of the present invention has: A stove containing a stove wall; The ammonia combustion burner with the structure of the above (1) is installed on the aforementioned furnace wall; and a control device that controls the injection amount of the ammonia fuel injected from the first ammonia injection nozzle, The ammonia fuel supplied to the first ammonia injection nozzle is liquid ammonia, The aforementioned ammonia combustion burner is equipped with a temperature sensor for detecting metal temperature. The aforementioned control device has: an injection amount calculation unit that calculates the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the temperature sensor; and The adjustment unit adjusts the injection amount to become the injection amount calculated by the injection amount calculation unit.

(6) The boiler operating method according to at least one embodiment of the present invention, It is a method of operating a boiler supplied with ammonia fuel. The aforementioned boiler contains: A stove containing a stove wall; The ammonia combustion burner with the structure of the above (1) is installed on the aforementioned furnace wall; and A fire detection sensor that detects fire inside the aforementioned combustion air nozzle, And have: The step of calculating the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor; and The injection amount is adjusted to the injection amount calculated in the calculating step.

(7) The boiler operating method according to at least one embodiment of the present invention, It is a method of operating a boiler supplied with ammonia fuel. The aforementioned boiler contains: A stove containing a stove wall; and The ammonia combustion burner with the structure of (1) above is installed on the wall of the aforementioned furnace, The ammonia fuel supplied to the first ammonia injection nozzle is liquid ammonia, The aforementioned ammonia combustion burner is equipped with a temperature sensor for detecting metal temperature. And have: The step of calculating the injection amount of the ammonia fuel before injecting it from the first ammonia injection nozzle based on the detection result of the temperature sensor; and The injection amount is adjusted to the injection amount calculated in the calculating step. [Effects of the invention]

According to at least one embodiment of the present invention, the amount of NOx generated by the ammonia combustion burner can be suppressed.

Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the constituent parts described as embodiments or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples. For example, relative or absolute expressions indicating "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" etc. are not strictly It only indicates this arrangement, but also includes tolerances, or a state of relative displacement with an angle or distance to the extent that the same function can be obtained. For example, expressions that express the equal state of things such as "same", "equal", and "homogeneous" do not strictly express only the equal state, but also include tolerances or exist to the extent that they can obtain the same function. Poor condition. For example, the representation of a shape such as a rectangular shape or a cylindrical shape does not only express a geometrically strict rectangular shape, a cylindrical shape, etc., but includes concave and convex portions within the range in which the same effect can be obtained. Or the shape of chamfered parts, etc. On the other hand, expressions such as "having", "having", "having", "containing", or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

<1. Overall structure of boiler system 1> FIG. 1 is a schematic structural diagram showing a boiler system 1 including a boiler using ammonia fuel and a fuel other than ammonia fuel as a main fuel according to this embodiment.

The boiler 10 included in the boiler system 1 of this embodiment burns ammonia fuel and fuels other than the ammonia fuel with a burner, and can produce superheated steam by exchanging heat with water supply or steam. of boiler. As other fuels, solid fuels such as biomass fuel or coal are used. Solid fuel is, for example, pulverized coal fuel obtained by finely pulverizing coal. Moreover, ammonia fuel is a liquid or gas containing ammonia.

The boiler 10 has a furnace 11, combustion devices 20 and 50, and a combustion gas passage 12. The stove 11 has a hollow shape of a square tube and is installed along the vertical direction. The furnace wall 101 constituting the inner wall of the furnace 11 is composed of a plurality of heat transfer tubes and connecting tube segments that connect the heat transfer tubes to each other. The heat generated by the combustion of fuel is circulated inside the heat transfer tubes. The water or steam is recovered through heat exchange, 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 stove 11 . In this embodiment, the combustion device 20 is configured to inject pulverized coal fuel into the inside of the furnace 11 . Furthermore, the combustion device 50 is configured to inject ammonia fuel into the inside of the furnace 11 .

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 ammonia burners (ammonia combustion burners) 51. An injection nozzle (not shown) is provided at the front end of each burner 21 and is configured to inject pulverized coal fuel into the furnace 11 . Furthermore, each ammonia burner 51 is provided with an ammonia injection nozzle (for example, the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 shown in FIG. 3 ). When a liquid ammonia injection method is used to inject liquid ammonia fuel into the furnace 11, the ammonia injection nozzle may be, for example, a two-fluid injection nozzle in which liquid ammonia is atomized by an atomized fluid such as steam and injected. A single fluid injection nozzle that injects only liquid ammonia fuel may also be used. Furthermore, when an ammonia gas injection method is used to inject gaseous ammonia fuel into the furnace 11, the ammonia injection nozzle may be a gas injection nozzle.

The burner 21 and the ammonia burner 51 are arranged at equal intervals along the circumferential direction of the furnace 11 (for example, four are provided at each corner of the square furnace 11) as a set, and Arrange multiple segments along the vertical direction. In the example of FIG. 1 , one set of burners 21 is arranged in two stages, and one set of ammonia burners 51 is arranged in four stages. In addition, in FIG. 1 , for the convenience of illustration, only two burners in one group are shown, and the symbols 21 and 51 are assigned to each group. The shape of the furnace, the number of burner stages, the number of burners per stage, the arrangement of the burners, etc. are not limited to this embodiment. Moreover, the combustion method of the stove 11 in this embodiment is a rotating combustion method in which burners are installed at the corners to form spirally rotating flames inside the stove 11, but other combustion methods are also possible. The shape of the furnace 11 and the arrangement of the plurality of burners 21 and the plurality of ammonia burners 51 may be appropriately changed according to the combustion method used. Another combustion method is, for example, an opposing combustion method in which burners are provided on both sides of a pair of opposing furnace walls of the furnace 11 .

The burner 21 of the combustion device 20 is connected to a plurality of pulverizers 31A, 31B (hereinafter sometimes referred to as "pulverized coal fuel supply pipes 22") through a plurality of pulverized coal fuel supply pipes 22A, 22B (hereinafter sometimes referred to as "pulverized coal fuel supply pipes 22"). In the following, they are collectively referred to as "pulverizer 31"). The grinder 31 has, for example, a grinding platform (not shown) that is rotatably supported internally, and a plurality of grinding rollers (not shown) above the grinding platform that are rotatably supported in conjunction with the rotation of the grinding platform. Vertical roller crusher. The solid fuel crushed by the cooperative operation of the crushing roller and the crushing platform is transported to the classifier (shown in the figure) provided in the crusher 31 by the primary air (transport gas, oxidizing gas) supplied to the crusher 31 omitted). In the classifier, the pulverized coal fuel is classified into pulverized coal fuel having a particle size smaller than or equal to the particle size suitable for combustion by the burner 21 and briquette fuel having a particle size larger than the particle size. The pulverized coal fuel is supplied to the burner 21 through the pulverized coal fuel supply pipe 22 together with the primary air through the classifier. The coal fuel that has not passed through the classifier falls to the crushing platform due to its own weight inside the crusher 31 and is crushed again.

The primary air (transport gas, oxidizing gas) supplied to the grinder 31 is sent to the grinder 31 through the air duct 30 from a primary air fan 33 (PAF: Primary Air Fan) that sucks in outside air. The air pipe 30 is provided with: a hot air induction pipe 30A through which hot air heated by an air heater (air preheater) 42 flows among the air sent from the primary air blower 33; and a cold air induction pipe 30B through which the hot air heated by the air heater (air preheater) 42 flows. Among the air sent from the primary air blower 33, there flows cold air close to normal temperature that has not passed through the air heater 42; and a transport gas flow path 30C that combines the hot air and the cold air to flow.

The ammonia burner 51 of the combustion device 50 is connected to the ammonia fuel supply unit 90 . The ammonia fuel supply unit 90 of this embodiment includes an ammonia tank 91 and an ammonia fuel supply pipe 92 for supplying ammonia fuel (for example, liquid ammonia) stored in the ammonia tank 91 to the combustion device 50 of the boiler 10 . When the ammonia gas injection method is used, a vaporizer (not shown) for vaporizing liquid ammonia may be provided in the ammonia fuel supply unit 90 . Furthermore, when the liquid ammonia injection method is adopted, the ammonia fuel supply unit 90 may further include an atomization fluid supply pipe (not shown) for supplying an atomization fluid for atomizing liquid ammonia to the combustion device 50 .

An air regulator (air box) 23 is provided outside the furnace 11 where the burner 21 and the ammonia burner 51 are installed, and one end of an air duct (air passage) 24 is connected to the air regulator 23 . The other end of the air duct 24 is connected to a forced draft fan (FDF) 32 . The air supplied from the blower fan 32 is heated by the air preheater 42 provided in the air duct 24, and is supplied to the burner as secondary air (combustion air, oxidizing gas) through the air regulator 23. 21, and is supplied to the ammonia burner 51 as combustion air (oxidizing gas), and is introduced into 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. The combustion gas passage 12 is provided with superheaters 102A, 102B, and 102C (hereinafter, sometimes collectively referred to as "superheaters 102") and reheaters 103A and 103B as heat exchangers for recovering the heat of the combustion gas. (Hereinafter, sometimes collectively referred to as the "reheater 103") and the economizer 104 perform heat exchange between the combustion gas generated in the furnace 11 and the water supply or steam flowing inside each heat exchanger. In addition, the arrangement and shape of each heat exchanger are not limited to the form shown in FIG. 1 .

A flue 13 for discharging the combustion gas superheated in the heat exchanger is connected to the downstream side of the combustion gas passage 12 . An air preheater (air heater) 42 is provided between the flue 13 and the air duct 24, and heat exchange is performed between the air flowing in the air duct 24 and the combustion gas flowing in the flue 13. The primary air supplied to the pulverizer 31 or the combustion air supplied to the burner 21 and the ammonia burner 51 is heated, thereby further recovering heat from the combustion gas after heat exchange with water or steam.

Furthermore, the flue 13 may be provided with a denitration device 43 at a position upstream of the air preheater 42 . The denitrification device 43 supplies a reducing agent that has the effect of reducing nitrogen oxides such as ammonia and urea water to the combustion gas flowing in the flue 13, so that the nitrogen oxides in the combustion gas to which the reducing agent is supplied are eliminated. The reaction between (NOx) and the reducing agent is promoted by the catalytic action of the denitration catalyst provided in the denitration device 43, thereby removing and reducing nitrogen oxides in the combustion gas. A gas passage 41 is connected to the flue 13 on the downstream side of the air preheater 42 . The gas passage 41 is provided with an environmental device such as a dust collecting device 44 such as an electric dust collector that removes ash in the combustion gas, a desulfurizing device 46 that removes sulfur oxides, or a device that guides the exhaust gas. Induced Draft Fan (IDF: Induced Draft Fan) 45 introduced to these environmental devices. The downstream end of the gas channel 41 is connected to the chimney 47, and the combustion gas processed by the environmental device is discharged out of the system as exhaust gas.

In the boiler 10, if a plurality of pulverizers 31 are driven, the pulverized coal fuel that has been crushed and classified will be supplied to the burner 21 through the pulverized coal fuel supply pipe 22 together with primary air. And, ammonia fuel is supplied from the ammonia fuel supply unit 90 to the ammonia burner 51 . In addition, the secondary air heated by the air preheater 42 is supplied from the air duct 24 through the air regulator 23 to the burner 21 and the ammonia burner 51 . The burner 21 blows the pulverized coal fuel mixture into the furnace 11 and blows the secondary air into the furnace 11 . The pulverized coal-fuel mixture blown into the furnace 11 is ignited and reacts with the secondary air to form a flame. The ammonia burner 51 blows combustion air into the furnace 11 together with ammonia fuel. The ammonia fuel blown into the furnace 11 reacts with the combustion air and burns. The high-temperature combustion gas generated by the combustion of pulverized coal fuel and ammonia fuel rises in the furnace 11 and flows into the combustion gas passage 12 . Furthermore, the timing at which the ammonia fuel is blown into the furnace 11 may be after the temperature in the furnace 11 has been raised to a certain temperature by burning the pulverized coal fuel. For example, after the pulverized coal fuel is exclusively burned when the boiler 10 is started, the ammonia fuel is blown into the furnace 11 and ammonia mixed combustion of the ammonia fuel and the pulverized coal fuel may be performed. After that, the injection of pulverized coal fuel may be stopped and ammonia-only combustion may be performed. In addition, in this embodiment, air is used as the oxidizing gas (primary air, secondary air, combustion air), but the proportion of oxygen may be more or less than that of air. The amount of supplied oxygen may be The ratio of the fuel amount is adjusted to an appropriate range, thereby achieving stable combustion in the stove 11 .

The combustion gas flowing into the combustion gas passage 12 exchanges heat with water or steam through the superheater 102, the reheater 103, and the economizer 104 arranged inside the combustion gas passage 12, and then is discharged to the flue 13. Nitrogen oxides are removed by the denitrification device 43, and the air preheater 42 performs heat exchange with the primary air, secondary air and combustion air, and then is further discharged to the gas passage 41, and is discharged by the dust collection device 44. Ash, etc. are removed, and sulfur oxides are removed by the desulfurization device 46, and then are discharged from the chimney 47 to the outside of the system. In addition, the arrangement of each device from each heat exchanger in the combustion gas passage 12 and the flue 13 to the gas passage 41 does not necessarily need to be arranged in the order described above for the flow of the combustion gas.

In addition, the boiler of this invention is not limited to the said embodiment. As solid fuel used in boilers, biomass fuel, petroleum coke (PC: Petroleum Coke) fuel, petroleum residue, etc. can be used instead of coal or together with coal. Furthermore, the fuel for the boiler combined with ammonia fuel is not limited to solid fuel, and liquid fuel such as petroleum fuel such as heavy oil, light oil, heavy oil, or factory waste liquid may also be used. In addition, gaseous fuels such as natural gas, various petroleum gases, and by-product gases generated in the steelmaking process can also be used. In addition, it can also be applied to mixed combustion boilers that use a combination of these various fuels. In the following description, ammonia fuel will also be referred to as ammonia.

As described above, the boiler 10 according to at least one embodiment of the present invention is provided with the furnace 11 including the furnace wall 101, the ammonia burner 51 provided on the furnace wall 101 to be described in detail later, and the ammonia burner 51 provided on the furnace wall 101. The burner 51 has different positions and the pulverized coal burner that burns the pulverized coal is the burner 21. Thereby, the NOx emission amount from the boiler 10 of at least one embodiment of this invention can be suppressed. In addition, the burner 21 may be another fuel burner that burns fuel other than ammonia fuel. Furthermore, the boiler 10 according to at least one embodiment of the present invention may be a mixed combustion boiler that combusts ammonia fuel and other fuels other than ammonia fuel, or an ammonia-specific combustion boiler that combusts only ammonia fuel.

(About the amount of NOx produced when burning ammonia with a burner) When a burner burns ammonia, the amount of NOx produced is more easily affected by the local air ratio at the contact surface between the fuel and combustion air at the combustion site than when burning other fuels. Therefore, in order to suppress the amount of NOx generated, it is important to control the local air ratio at the contact surface between ammonia and combustion air in the combustion site. Therefore, in the boiler 10 of this embodiment, the ammonia burner 51 is configured as follows, thereby suppressing the generation amount of NOx.

(About the first ammonia burner 51A) 2 is a side cross-sectional view schematically showing the structure of the first ammonia burner 51A according to one of the several embodiments of the ammonia burner 51, along the central axis Ax from the flow direction of the combustion air. The schematic front view of the first ammonia burner 51A is viewed from the downstream side. 6 is a side cross-sectional view schematically showing the structure of the first ammonia burner 51A provided with the protruding portion 57. The first ammonia burner is viewed from the downstream side in the flow direction of the combustion air along the central axis Ax. Schematic front view of burner 51A.

The first ammonia burner 51A shown in FIG. 6 has the same structure as the first ammonia burner 51A shown in FIG. 2 except that the protrusion 57 is provided. In addition, the protruding portion 57 will be described later. The first ammonia burner 51A shown in FIGS. 2 and 6 is provided with a combustion air nozzle 54 for injecting combustion air. The first ammonia burner 51A shown in FIGS. 2 and 6 includes a first ammonia injection nozzle 521 disposed inside the combustion air nozzle 54 and for injecting ammonia fuel into the combustion air nozzle 54 . The first ammonia burner 51A shown in FIGS. 2 and 6 includes a flame retainer 56 arranged downstream of the first ammonia injection nozzle 521 . In the first ammonia burner 51A shown in FIGS. 2 and 6 , the flame retainer 56 is, for example, a hollow truncated cone-shaped diffusion-type flame retainer 56A. The first ammonia burner 51A shown in FIGS. 2 and 6 may also be equipped with a second ammonia injection nozzle 522 for injecting ammonia fuel downstream of the flame retainer 56 . In addition, in the first ammonia burner 51A shown in FIGS. 2 and 6 , the second ammonia injection nozzle 522 is not necessary.

In the first ammonia burner 51A shown in FIGS. 2 and 6 , the combustion air nozzle 54 has a rectangular shape when viewed along the central axis Ax, and is a passage having a rectangular cross section. In the vicinity, the flow path cross-sectional area is formed to become smaller toward the downstream side while maintaining the rectangular cross-sectional shape. In addition, the cross-sectional shape of the combustion air nozzle 54 is not limited to a rectangular shape. In the first ammonia burner 51A shown in FIGS. 2 and 6 , the combustion air nozzle 54 has an opening 54 a for injecting combustion air.

The first ammonia burner 51A shown in FIGS. 2 and 6 is configured to premix a part of the combustion air and the ammonia fuel injected from the first ammonia injection nozzle 521 in the combustion air nozzle 54 . Thereby, in the first ammonia burner 51A shown in FIGS. 2 and 6 , the first ammonia injection nozzle 521 is used to ensure a part of the air for combustion in the combustion air nozzle 54 and from the first ammonia injection nozzle 521 as follows. The premixed area of the ammonia fuel injected by the first ammonia injection nozzle 521 is arranged upstream of the opening 54 a of the outlet of the combustion air nozzle 54 . In the first ammonia burner 51A shown in FIGS. 2 and 6 , a plurality of first ammonia injection nozzles 521 are arranged at intervals in the circumferential direction around the central axis Ax. In the example shown in FIGS. 2 and 6 , four first ammonia injection nozzles 521 are arranged at intervals in the circumferential direction around the central axis Ax.

As described above, in the first ammonia burner 51A shown in FIGS. 2 and 6 , the combustion air nozzle 54 is configured to inject a part of the combustion air and the ammonia fuel injected from the first ammonia injection nozzle 521 . Remaining portion of partially premixed fuel, combustion air.

In the first ammonia burner 51A shown in FIGS. 2 and 6 , a gap is formed between the opening 54 a of the combustion air nozzle 54 and the outer edge of the flame retainer 56 . The gap is a passage for causing at least a part of the partially premixed fuel and the remaining part of the combustion air to be ejected from the gap. In addition, since the first ammonia burner 51A shown in FIGS. 2 and 6 is provided with a diffusion type flame retainer 56A, all of the partially premixed fuel is sprayed from the gap.

In the first ammonia burner 51A shown in FIGS. 2 and 6 , the ammonia supplied to the first ammonia burner 51A is, for example, gaseous ammonia fuel (ammonia gas). In addition, the ammonia fuel supplied to the first ammonia burner 51A may be liquid ammonia fuel as will be described later.

In the first ammonia burner 51A shown in FIGS. 2 and 6 , the second ammonia injection nozzle 522 is arranged coaxially with the combustion air nozzle 54 and is configured to inject ammonia into the furnace 11 from a plurality of injection holes 52 h.

In the thus configured first ammonia burner 51A shown in FIGS. 2 and 6 , the ammonia injected from the first ammonia injection nozzle 521 shown by arrow a in FIGS. 2 and 6 is as shown in FIGS. 2 and 6 A part of the combustion air shown by the dotted arrow b will be premixed in the combustion air nozzle 54 to produce partial premixed fuel. This part of the premixed fuel is injected into the furnace 11 from the gap between the opening 54a of the combustion air nozzle 54 and the outer edge of the flame holder 56 as shown by arrow c. In addition, the remaining part of the combustion air that has not been premixed with ammonia is injected into the furnace 11 from the above-mentioned gap as shown by the dotted arrow d in FIG. 2 and FIG. 6 . In the first ammonia burner 51A shown in FIGS. 2 and 6 , ammonia supplied to the second ammonia injection nozzle 522 is injected into the furnace from a plurality of injection holes 52 h as shown by arrows e in FIGS. 2 and 6 Within 11.

The first ammonia burner 51A shown in FIGS. 2 and 6 is provided with a partition wall 625 that separates the flow path 541 of the partial premixed fuel from the flow path 542 of the remaining part of the combustion air. The partition wall 625 is, for example, a cylindrical member coaxial with the first ammonia burner 51A as the central axis Ax. The inner peripheral surface 625a of the partition wall 625 defines a flow path 541 for the partial premixed fuel, and the outer peripheral surface 625b of the partition wall 625 forms a residual portion of the combustion air between the partition wall 625 and the inner peripheral surface 54i of the combustion air nozzle 54. Flow path 542.

The combustion air partially premixed with ammonia flows from the upstream opening end of the partition wall 625 into the flow path of the partially premixed fuel inside the partition wall 625 as indicated by the dotted arrow b in FIGS. 2 and 6 541. Part of the premixed fuel flows out from the open end on the downstream side of the partition wall 625 toward the inside of the furnace 11 as shown by the dotted arrow c in FIGS. 2 and 6 .

The remaining portion of the combustion air that has not been premixed with ammonia flows outside the partition wall 625 and flows out into the furnace 11 as shown by the dotted arrows f and d in FIGS. 2 and 6 . This can suppress premixing of more than necessary combustion air and ammonia fuel inside the combustion air nozzle 54, making it easier to stabilize the air ratio of the partially premixed fuel.

The reason why the NOx generation amount is suppressed in the ammonia burner 51 of several embodiments will be explained below. Fig. 3 is a schematic diagram illustrating the contact state between ammonia fuel and combustion air. Fig. 4 is a graph for explaining the air ratio at the contact surface between ammonia fuel and combustion air. The graph in FIG. 4 shows the area where the injected ammonia fuel or partially premixed fuel comes into contact with the injected combustion air, and shows how the air ratio changes from the fuel side toward the combustion air side. In the graph of FIG. 4 , the graph line when the ammonia fuel is diffused and burned is represented by a dotted line, and the graph line when the partial premixed fuel and combustion air premixed in the combustion air nozzle 54 are burned is represented by a solid line. Line representation.

In FIG. 3 , with the central axis Ax of the ammonia burner 51X along the flow of the combustion air as a boundary, on the upper side of the figure, similarly to the above-described first ammonia burner 51A, the combustion air nozzle is shown. 54, the partially premixed fuel and combustion air that have been premixed are injected and burned (partially premixed combustion). Furthermore, with the central axis Ax as a boundary, on the lower side of the figure, a state in which ammonia fuel is diffused and burned is shown.

As shown on the lower side of FIG. 3 , when ammonia fuel is diffused and burned, the entire amount of combustion air and ammonia fuel are diffusely mixed. Thereby, the contact surface S1 between the injected ammonia fuel F1 and the injected combustion air A1 becomes relatively wide. Furthermore, it is considered that the local air ratio at the contact surface S1 exceeds 1, creating an environment in which NOx is likely to be generated (see FIG. 4 ).

As shown in the upper side of FIG. 3 , when the premixed fuel and the combustion air are premixed in the combustion air nozzle 54 , part of the combustion air is premixed with the ammonia fuel in the combustion air nozzle 54 . Mixed and ejected to the combustion site. It is then diffused and mixed with the remaining part of the combustion air in the furnace 11 . In this case, the flow rate of diffusion mixed combustion air will reduce the amount used for premixing, so the contact surface S2 between the injected part of the premixed fuel F2 and the injected combustion air A2 is The situation will narrow in comparison. Furthermore, the local air ratio at the contact surface S2 is lower than when ammonia fuel is diffusely burned (see FIG. 4 ). Therefore, when a portion of the premixed fuel premixed in the combustion air nozzle 54 is combusted with the combustion air, the amount of NOx generated can be suppressed compared with a case where ammonia fuel is diffusely combusted.

Thereby, the NOx generation amount can be suppressed in the first ammonia burner 51A shown in FIGS. 2 and 6 .

In the first ammonia burner 51A shown in FIGS. 2 and 6 , the above-mentioned part of the premixed fuel and the combustion air are sprayed from the gap between the opening 54 a of the combustion air nozzle 54 and the outer edge of the flame retainer 56 . The residual part of the air can thereby narrow the contact surface between the partially premixed fuel and the combustion air during the diffusion mixing. Thereby, the amount of NOx generated by the first ammonia burner 51A can be suppressed.

Since the first ammonia burner 51A shown in FIGS. 2 and 6 is provided with a diffusion type flame retainer 56A, it is possible to maintain flame near the first ammonia burner 51A and suppress the diffusion and mixing of parts. The contact surface between premixed fuel and combustion air becomes wider. Thereby, the amount of NOx generated by the first ammonia burner 51A can be suppressed.

In the first ammonia burner 51A shown in FIGS. 2 and 6 , at least a part of the flame retainer 56 may be located in the injection range of the ammonia fuel injected by the first ammonia injection nozzle 521 . Thereby, it is expected that the ammonia fuel injected by the first ammonia injection nozzle 521 will cool the flame heater 56 and suppress the temperature rise of the flame heater 56 .

The first ammonia burner 51A shown in FIGS. 2 and 6 is provided with a second ammonia injection nozzle 522, whereby the ammonia fuel injected from the second ammonia injection nozzle 522 can be diffusely combusted.

In addition, in the first ammonia burner 51A shown in FIGS. 2 and 6 , for example, when the load of the boiler 10 changes, the required combustion amount of the first ammonia burner 51A depends on the operating conditions of the boiler 10 . Ammonia may be injected from the first ammonia injection nozzle 521 , ammonia may be injected only from the second ammonia injection nozzle 522 , or ammonia may be injected from both the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 .

(About the second ammonia burner 51B) Fig. 5 is a side cross-sectional view schematically showing the structure of the second ammonia burner 51B according to one of several embodiments of the ammonia burner 51. It is viewed from the flow direction of the combustion air along the central axis Ax. The schematic front view of the second ammonia burner 51B is viewed from the downstream side. The second ammonia burner 51B shown in Figure 5 is different from the first ammonia burner 51A shown in Figure 2 except for the structure of the flame retainer 56. Same construction as 51A. That is, the second ammonia burner 51B shown in FIG. 5 is provided with the combustion air nozzle 54 for injecting combustion air. The second ammonia burner 51B shown in FIG. 5 includes a first ammonia injection nozzle 521 disposed inside the combustion air nozzle 54 and for injecting ammonia fuel into the combustion air nozzle 54 . The second ammonia burner 51B shown in FIG. 5 includes a flame retainer 56 arranged downstream of the first ammonia injection nozzle 521 . In the second ammonia burner 51B shown in FIG. 5 , the flame retainer 56 is, for example, a swirl-type flame retainer 56B having a plurality of rotating blades. The first ammonia burner 51A shown in FIG. 2 may also be equipped with a second ammonia injection nozzle 522 for injecting ammonia fuel downstream of the flame retainer 56 . In addition, in the first ammonia burner 51A shown in FIG. 2, the second ammonia injection nozzle 522 is not necessary.

The second ammonia burner 51B shown in FIG. 5 is configured to premix a part of the combustion air and the ammonia fuel injected from the first ammonia injection nozzle 521 in the combustion air nozzle 54 . Thereby, in the second ammonia burner 51B shown in FIG. 5, the first ammonia injection nozzle 521 is used to ensure a part of the combustion air in the combustion air nozzle 54 and is injected from the first ammonia injection nozzle 521. The area where the ammonia fuel is premixed is arranged upstream of the opening 54a at the outlet of the combustion air nozzle 54. In the second ammonia burner 51B shown in FIG. 5 , a plurality of first ammonia injection nozzles 521 are arranged at intervals in the circumferential direction around the central axis Ax. In the example shown in FIG. 5 , four first ammonia injection nozzles 521 are arranged at intervals in the circumferential direction around the central axis Ax.

As described above, in the second ammonia burner 51B shown in FIG. 5 , the combustion air nozzle 54 is configured to inject: a part of the combustion air and a part of the ammonia fuel injected from the first ammonia injection nozzle 521 are premixed. The remaining portion of fuel and combustion air.

In the second ammonia burner 51B shown in FIG. 5 , a gap is formed between the opening 54 a of the combustion air nozzle 54 and the outer edge of the flame retainer 56 . The gap is a passage for causing at least a part of the partially premixed fuel and the remaining part of the combustion air to be ejected from the gap. In addition, the second ammonia burner 51B shown in FIG. 5 is equipped with a swirl-type flame retainer 56B, so most of the partial premixed fuel will rotate from a plurality of swirl-type flame retainers 56A. The partially premixed fuel is ejected from the opening between the blades, and a part of the partially premixed fuel is ejected from the gap.

In the second ammonia burner 51B shown in FIG. 5 , the ammonia fuel supplied to the second ammonia burner 51B is, for example, gaseous ammonia fuel (ammonia gas). In addition, the ammonia supplied to the second ammonia burner 51B may be liquid ammonia fuel as will be described later.

In the second ammonia burner 51B shown in FIG. 5 , the second ammonia injection nozzle 522 is arranged coaxially with the combustion air nozzle 54 and is configured to inject ammonia fuel into the furnace 11 from a plurality of injection holes 52 h.

In the second ammonia burner 51B shown in FIG. 5 , similarly to the first ammonia burner 51A shown in FIG. 2 , the combustion air nozzle 54 is configured to inject a part of the combustion air from the first Part of the ammonia fuel injected from the ammonia injection nozzle 521 is premixed with the remaining part of the combustion air, so the amount of NOx generated can be suppressed.

The second ammonia burner 51B shown in FIG. 5 injects a part of the partial premixed fuel and the combustion air from the gap between the opening 54a of the combustion air nozzle 54 and the outer edge of the flame retainer 56. The remaining part can thereby narrow the contact surface between part of the premixed fuel and the combustion air during diffusion mixing. Thereby, the amount of NOx generated by the second ammonia burner 51B can be suppressed.

The second ammonia burner 51B shown in FIG. 5 is equipped with a swirl-type flame retainer 56B, so that it can maintain flame near the first ammonia burner 51A and suppress partial premixing during diffusion mixing. The contact surface between fuel and combustion air becomes wider. Thereby, the amount of NOx generated by the second ammonia burner 51B can be suppressed.

In the second ammonia burner 51B shown in Figure 5, the flame retainer 56 is a swirl type flame retainer 56B, so the metal temperature of the flame retainer 56 can be suppressed compared with the diffusion type flame retainer 56A. . This is because the cyclone type flame retainer 56B has a smaller heating area compared with the diffusion type flame retainer 56A. This is because the contact area of the fluid (partially premixed fuel, combustion air) in the combustion air nozzle 54 is large.

In the second ammonia burner 51B shown in FIG. 5 , at least a part of the flame retainer 56 is located in the injection range of the ammonia fuel injected by the first ammonia injection nozzle 521 . Thereby, it is expected that the ammonia fuel injected by the first ammonia injection nozzle 521 can cool the insulator and suppress the temperature rise of the insulator.

The second ammonia burner 51B shown in FIG. 5 is provided with a second ammonia injection nozzle 522, whereby the ammonia fuel injected from the second ammonia injection nozzle 522 can be diffusely combusted.

In addition, in the second ammonia burner 51B shown in FIG. 5 , for example, when the load of the boiler 10 changes, the required combustion amount of the second ammonia burner 51B according to the operating conditions of the boiler 10 only changes from the first to the second ammonia burner 51B. Ammonia may be injected from the ammonia injection nozzle 521 , ammonia may be injected from only the second ammonia injection nozzle 522 , or ammonia may be injected from both the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 .

(About the temperature suppression of the flame protector 56) In the first ammonia burner 51A shown in Figure 2, the flame retainer 56 is a diffusion type flame retainer 56A. Therefore, compared with the swirl type flame retainer 56B, the metal temperature of the flame retainer 56 is higher. High tendency. This is because the diffusion type flame retainer 56A has a larger heating area compared with the swirl type flame retainer 56B, from the combustion gas in the furnace 11 and the radiant heat of the flame formed by itself. This is because the contact area of the fluid (fuel, partially premixed fuel, and combustion air) in the combustion air nozzle 54 is small. Therefore, as shown in FIG. 6 , the first ammonia burner 51A may be provided with a protruding portion (connecting piece) 57 connected to the flame retainer 56 and protruding toward the upstream side of the flame retainer 56 .

As shown in FIG. 6 , for example, the protrusion 57 is a plate-shaped member formed to protrude toward the upstream side of the diffuser 56A by connecting its upstream end to the upstream surface of the diffusion-type inflammator 56A. . For example, the protruding portions 57 are arranged in plural numbers at intervals in the circumferential direction around the central axis Ax. In the example shown in FIG. 6 , four protruding portions 57 are arranged at intervals in the circumferential direction around the central axis Ax. In the first ammonia burner 51A shown in FIG. 6 , the protruding portion 57 contacts and cools a portion of the premixed fuel or combustion air that has been premixed in the combustion air nozzle 54 , thereby suppressing the damage of the flame retainer 56 . The temperature rises.

(About the case of injecting liquid ammonia) As described above, the ammonia burner 51 of some embodiments may be configured to inject liquid ammonia fuel. In this case, a nozzle head (atomizer) capable of spraying liquid ammonia fuel may be installed at the front ends of the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 . FIG. 7A is a cross-sectional view schematically showing an example of the structure of the pressure spray nozzle 525. FIG. 7B is a schematic diagram of the back plate 525a disposed inside the pressure spray nozzle 525 shown in FIG. 7A. FIG. 8 is a cross-sectional view schematically showing an example of the structure of the two-fluid spray nozzle 526.

The nozzle head installed at the front end of the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 may be a pressure spray nozzle 525 as shown in FIG. 7A , or a two-fluid spray nozzle 526 as shown in FIG. 8 .

For example, in the pressure spray nozzle 525 shown in FIG. 7A , when the liquid ammonia passes through the back plate arranged inside, the flow direction is changed to have a radial velocity component, and the liquid ammonia fuel sprayed from the pressure spray nozzle 525 is Gives rotational force. Thereby, the liquid ammonia fuel is sprayed from the pressure spray nozzle 525 in a cone shape, for example.

For example, in the two-fluid spray nozzle 526 shown in FIG. 8 , the liquid ammonia fuel is atomized by an atomization fluid supplied separately from the fuel, and is sprayed from the two-fluid spray nozzle 526 . When the first ammonia injection nozzle 521 and the second ammonia injection nozzle 522 use the two-fluid spray nozzle 526 as shown in FIG. 8 , superheated steam, air, nitrogen, or the like is used as the atomized fluid.

As described above, the liquid ammonia fuel is sprayed from the ammonia burner 51 of some embodiments, thereby cooling the flame retainer 56 and the like by the vaporization heat of the liquid ammonia fuel injected from the first ammonia injection nozzle 521 . Thereby, the temperature rise of the flame-retaining device 56 etc. can be suppressed.

(About adjustment of the ammonia injection amount from the first ammonia injection nozzle 521) In the boiler 10 provided with the ammonia burner 51 of the above embodiments, the ammonia injection amount from the first ammonia injection nozzle 521 can also be adjusted as follows. FIG. 9 is a diagram for explaining the adjustment of the ammonia injection amount from the first ammonia injection nozzle 521 of the ammonia burner 51 according to several embodiments. In addition, the ammonia burner 51 shown in Fig. 9 is the first ammonia burner 51A shown in Fig. 2, but it may also be the second ammonia burner 51B shown in Fig. 5, or it may be the one shown in Fig. 6 The first ammonia burner 51A is shown.

The boiler 10 including the ammonia burner 51 of several embodiments is provided with a control device 900 for controlling the ammonia injection amount from the first ammonia injection nozzle 521 . The control device 900 in several embodiments includes a controller 901 and an adjustment unit 95 .

The controller 901 includes a processor 901a that performs various calculation processes, and a memory 901b that temporarily or non-temporarily stores various data processed by the processor. The processor is implemented by a CPU, GPU, MPU, DSP, various computing devices other than these, or a combination thereof. Memory is implemented by ROM, RAM, flash memory, or a combination of these. Furthermore, the controller 901 may be configured to control the boiler 10 . The controller 901 may be configured to control the boiler system 1 .

The controller 901 includes an injection amount calculation unit 902 as a functional block. The processor 901a of the controller 901 executes a program stored in the memory to function as the injection amount calculation unit 902.

The regulator 95 is, for example, a first flow rate regulating valve 95A for regulating the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 . In addition, the adjustment unit 95 may include a second flow rate adjustment valve 95B for adjusting the injection amount of the ammonia fuel injected from the second ammonia injection nozzle 522, and a second flow adjustment valve 95B for adjusting the combustion air supplied to the combustion air nozzle 54. The third flow rate regulating valve 95C supplies the amount.

The ammonia burner 51 of several embodiments may also be equipped with a temperature sensor 96 for detecting the metal temperature of the ammonia burner 51 . The temperature sensor 96 may be, for example, a thermocouple, and may be mounted on a metal part in the combustion air nozzle 54 relatively close to the opening 54a. The temperature sensor 96 may be installed to detect the temperature of the partition wall 625 as shown in FIG. 9 , or may be installed to detect the temperature near the downstream end of the first ammonia injection nozzle 521 . Furthermore, the temperature sensor 96 may be installed to detect the temperature of the heat protector 56 . In addition, the temperature sensor 96 may be provided to detect temperatures other than the above-mentioned several detection locations. The temperature sensor 96 only needs to be configured to detect the temperature of at least one of the detection locations. The temperature sensor 96 functions as the ignition detection sensor 98 when used to detect ignition inside the combustion air nozzle 54 as will be described later. The ammonia burner 51 in some embodiments is equipped with a temperature sensor 96 that detects the metal temperature of the combustion air nozzle 54. Therefore, as will be described later, the metal temperature of the combustion air nozzle 54 can be managed.

The ammonia burner 51 of some embodiments may also be equipped with a pressure sensor 97 for detecting the pressure in the combustion air nozzle 54 . Furthermore, the pressure sensor 97 functions as the ignition detection sensor 98 when used to detect ignition inside the combustion air nozzle 54 as will be described later. If the pressure sensor 97 is used as the ignition detection sensor 98 as described later, the pressure change of the combustion air inside the combustion air nozzle 54 can be detected. Therefore, the pressure sensor 97 is not necessarily required. inside the combustion air nozzle 54.

In the boiler 10 including the ammonia burner 51 of several embodiments, the detection signal from the temperature sensor 96 or the pressure sensor 97 is input to the controller 901 . In the boiler 10 including the ammonia burner 51 of several embodiments, the first flow rate regulating valve 95A, the second flow rate regulating valve 95B, and the third flow rate regulating valve 95C are respectively provided with not-shown flow rate regulating valves for adjusting the flow rate. of actuators. In the boiler 10 including the ammonia burner 51 of several embodiments, the control signals for driving the actuators are configured to be output from the controller 901 .

(The case where the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 is controlled in order to suppress ignition inside the combustion air nozzle 54 ) In the boiler 10 including the ammonia burner 51 of several embodiments, the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 may be controlled based on the detection result of the ignition detection sensor 98 .

FIG. 10 is a flowchart showing a process flow for controlling the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the ignition detection sensor 98 . The program for executing the processing shown in the flowchart of FIG. 10 is read and executed by the processor 901a from the memory 901b.

The operating method of the boiler 10 according to one embodiment includes step S10 of calculating the injection amount and step S20 of adjusting the injection amount.

Step S10 of calculating the injection amount is a step of calculating the injection amount of ammonia fuel injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor 98 . In step S10 of calculating the injection amount, the injection amount calculation unit 902 of the controller 901 determines whether the inside of the combustion air nozzle 54 is ignited based on the detection result of the ignition detection sensor 98 . For example, in step S10 of calculating the injection amount, the injection amount calculation unit 902 may determine whether the inside of the combustion air nozzle 54 is ignited based on the temperature detected by the temperature sensor 96, a change in the temperature, or the like. For example, in step S10 of calculating the injection amount, the injection amount calculation unit 902 determines based on the pressure of the combustion air supplied to the combustion air nozzle 54 detected by the pressure sensor 97, changes in the pressure, etc. It does not matter whether the inside of the combustion air nozzle 54 is on fire. Then, the injection amount calculation unit 902 determines that there is a fire inside the combustion air nozzle 54, and sets the setting value of the injection amount from the first ammonia injection nozzle 521 to an injection amount that is smaller than the current ammonia injection amount, for example. quantity. In addition, when the injection amount calculation unit 902 sets the setting value of the injection amount from the first ammonia injection nozzle 521 to an injection amount smaller than the current ammonia injection amount, it is equivalent to the injection amount from the first ammonia injection nozzle 521 In proportion to the reduction in the injection amount, the setting value of the injection amount from the second ammonia injection nozzle 522 may be set to an injection amount greater than the current ammonia injection amount.

Step S20 of adjusting the injection amount is a step of adjusting the injection amount from the first ammonia injection nozzle 521 to the injection amount calculated in step S10 of calculating the injection amount. In step S20 of adjusting the injection amount, the processor 901a outputs a control signal for driving an actuator (not shown) of the first flow rate regulating valve 95A to become the value calculated (set) in step S10 of calculating the injection amount. Injection volume. The first flow rate regulating valve 95A receives the control signal and adjusts the ammonia flow rate of the first flow rate regulating valve 95A with an actuator (not shown). Thereby, the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 becomes the injection amount calculated (set) in step S10 of calculating the injection amount. Thereby, the risk of backfire inside the ammonia burner 51 can be reduced. Furthermore, in step S20 of adjusting the injection amount, the processor 901a may also output a control signal for driving an actuator (not shown) of the second flow rate regulating valve 95B, so that the injection amount from the first ammonia injection nozzle 521 becomes The injection amount calculated (set) in step S10 of calculating the injection amount. The second flow rate regulating valve 95B receives the control signal and adjusts the flow rate of ammonia in the second flow rate regulating valve 95B with an actuator (not shown). Thereby, the injection amount of the ammonia fuel injected from the second ammonia injection nozzle 522 becomes the injection amount calculated (set) in step S10 of calculating the injection amount.

That is, the boiler 10 including the ammonia burner 51 of several embodiments is equipped with an ignition detection sensor 98 that detects ignition inside the combustion air nozzle 54 , and an ignition detection sensor 98 that detects ignition based on the detection result of the ignition detection sensor 98 . A control device 900 for controlling the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 . The control device 900 includes an injection amount calculation unit 902 that calculates an injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the ignition detection sensor 98 , and an injection amount calculation unit 902 that adjusts the injection amount to The adjustment unit 95 of the calculated injection amount.

(The case where the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 is controlled in order to suppress the metal temperature of the ammonia burner 51 ) In the boiler 10 including the ammonia burner 51 of several embodiments, the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 may be controlled based on the detection result of the temperature sensor 96 .

FIG. 11 is a flowchart showing a process flow for controlling the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the temperature sensor 96 . The program for executing the processing shown in the flowchart of FIG. 11 is read and executed by the processor 901a from the memory 901b.

The operating method of the boiler 10 according to one embodiment includes step S50 of calculating the injection amount and step S60 of adjusting the injection amount.

Step S10 of calculating the injection amount is a step of calculating the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the temperature sensor 96 . In step S10 of calculating the injection amount, the injection amount calculation unit 902 of the controller 901 monitors the detection result of the temperature sensor 96 , that is, monitors the metal temperature detected by the temperature sensor 96 . Then, for example, the injection amount calculation unit 902 determines that the metal temperature detected by the temperature sensor 96 exceeds a preset threshold, and sets the setting value of the injection amount from the first ammonia injection nozzle 521 to be higher than the current ammonia injection rate. The injection volume is more than the injection volume. In addition, when the injection amount calculation unit 902 sets the setting value of the injection amount from the first ammonia injection nozzle 521 to an injection amount greater than the current ammonia injection amount, it is equivalent to the injection amount from the first ammonia injection nozzle 521 In proportion to the increase in the injection amount, the setting value of the injection amount from the second ammonia injection nozzle 522 may be set to an injection amount smaller than the current ammonia injection amount.

For example, if the structure of the ammonia burner 51 is different, the front end of the combustion air nozzle 54 or the flame retainer 56 that constitutes the ammonia burner 51 will be affected by the flame generated from the combustion gas in the furnace 11 or the ammonia burner 51 The degree of damage due to heat (hereinafter referred to as burn damage) will also vary. Then, in step S10 of calculating the injection amount, the injection amount calculation unit 902 may change the injection amount from the first ammonia injection nozzle 521 for suppressing the metal temperature according to the structure of the ammonia burner 51 . Furthermore, in step S10 of calculating the injection amount, the injection amount calculation unit 902 predicts a change in the metal temperature based on the metal temperature detected by the temperature sensor 96, and sets the injection amount from the first ammonia injection nozzle 521 based on the predicted temperature change. The injection volume is also available. In addition, when predicting changes in the metal temperature, the injection amount calculation unit 902 may take into consideration the combustion air ratio of the ammonia burner 51 , the structure of the ammonia burner 51 , and the load of the boiler 10 .

Step S60 of adjusting the injection amount is a step of adjusting the injection amount from the first ammonia injection nozzle 521 to the injection amount calculated in step S50 of calculating the injection amount. In step S60 of adjusting the injection amount, the processor 901a outputs a control signal for driving an actuator (not shown) of the first flow rate regulating valve 95A to become the value calculated (set) in step S50 of calculating the injection amount. Injection volume. The first flow rate regulating valve 95A receives the control signal and adjusts the ammonia flow rate of the first flow rate regulating valve 95A with an actuator (not shown). Thereby, the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 becomes the injection amount calculated (set) in step S50 of calculating the injection amount. Thereby, the metal temperature of the ammonia burner 51 is suppressed from rising, and the occurrence of burning loss can be suppressed. In addition, in the case where the metal temperature of the ammonia burner 51 is suppressed by increasing the injection amount from the first ammonia injection nozzle 521 as described above, the ammonia fuel supplied to the first ammonia injection nozzle 521 is more effective than the liquid ammonia fuel. big. The heat of vaporization of the liquid ammonia injected from the first ammonia injection nozzle 521 can cool the flame retainer 56 and the like. Thereby, the temperature rise of the flame holder 56 etc. can be suppressed more effectively. In step S60 of adjusting the injection amount, the processor 901a may also output a control signal for driving an actuator (not shown) of the second flow rate regulating valve 95B, so that the injection amount from the first ammonia injection nozzle 521 becomes the calculated amount. The injection amount is the injection amount calculated (set) in step S50. The second flow rate regulating valve 95B receives the control signal and adjusts the flow rate of ammonia in the second flow rate regulating valve 95B with an actuator (not shown). Thereby, the injection amount of the ammonia fuel injected from the second ammonia injection nozzle 522 becomes the injection amount calculated (set) in step S50 of calculating the injection amount.

As described above, the boiler 10 including the ammonia burner 51 of several embodiments is provided with the control device 900 for controlling the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 . The ammonia fuel supplied to the first ammonia injection nozzle 521 may be liquid ammonia fuel. The ammonia burner 51 is equipped with a temperature sensor 96 that detects metal temperature. The control device 900 includes an injection amount calculation unit 902 that calculates the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the temperature sensor 96, and adjusts the injection amount to a value determined by the injection amount calculation unit 902. The adjustment part 95 of the calculated injection amount.

The present invention is not limited to the above-described embodiments, but also includes modifications of the above-described embodiments and modifications of these embodiments, as well as modifications of these embodiments.

The contents described in each of the above embodiments can be understood as follows, for example. (1) The ammonia combustion burner (ammonia burner 51) according to at least one embodiment of the present invention is an ammonia combustion burner for burning ammonia fuel in the boiler 10. An ammonia combustion burner (ammonia burner 51) according to at least one embodiment of the present invention is provided with a combustion air nozzle 54 for injecting combustion air. An ammonia combustion burner (ammonia burner 51) according to at least one embodiment of the present invention is provided with a first ammonia injection nozzle arranged inside the combustion air nozzle 54 and for injecting ammonia fuel into the combustion air nozzle 54. 521. An ammonia combustion burner (ammonia burner 51) according to at least one embodiment of the present invention includes a flame retainer 56 arranged downstream of the first ammonia injection nozzle 521. The combustion air nozzle 54 is configured to inject a part of the combustion air, a part of the ammonia fuel injected from the first ammonia injection nozzle 521 , a premixed fuel, and a remaining part of the combustion air.

According to the structure of (1) above, the local air ratio at the contact surface between the ammonia fuel and the combustion air in the combustion site is more likely to be smaller than the local air ratio at the contact surface between the ammonia fuel and the combustion air in the combustion site without premixing. The local air ratio at the contact surface between the remaining parts becomes lower. Moreover, according to the structure of the above (1), compared with the case without premixing, the flow rate of the combustion air for diffusion mixing is reduced because it is used for partial premixing in advance, so the combustion air during diffusion mixing can be reduced. The contact surface between air and partially premixed fuel becomes narrower. Thereby, the amount of NOx generated by the ammonia combustion burner (ammonia burner 51) can be suppressed.

(2) In some embodiments, in the structure of (1) above, the combustion air nozzle 54 may have an opening 54a for blowing out combustion air. A gap may be formed between the opening 54a and the outer edge of the flame holder 56. The gap may be a passage for causing at least a part of the partially premixed fuel and the remaining part of the combustion air to be ejected from the gap.

According to the structure of the above (2), at least a part of the partially premixed fuel and the remaining part of the combustion air are sprayed from the above gap, whereby the contact between the combustion air and the partially premixed fuel can be reduced during diffusion mixing. The face becomes narrower. Thereby, the amount of NOx generated by the ammonia combustion burner (ammonia burner 51) can be suppressed.

(3) In some embodiments, in the structure of (1) or (2) above, a partition wall 625 is provided to separate the flow path 541 of the partial premixed fuel from the flow path 542 of the remaining part of the combustion air. Can.

According to the structure of (3) above, premixing of more than necessary combustion air and ammonia fuel inside the combustion air nozzle 54 can be suppressed, so it is easy to stabilize the air ratio of the partially premixed fuel.

(4) In some embodiments, in any one of the structures (1) to (3) above, the flame retaining device 56 may be a diffusion type or a swirling flow type flame retaining device.

According to the structure of the above (4), flame can be maintained near the ammonia combustion burner (ammonia burner 51), so the contact surface between the combustion air and the partially premixed fuel during diffusion mixing can be suppressed from widening. situation. Thereby, the amount of NOx generated by the ammonia combustion burner (ammonia burner 51) can be suppressed.

(5) In some embodiments, in any of the structures (1) to (4) above, at least a part of the flame retainer 56 may be located in the injection range of the ammonia fuel injected by the first ammonia injection nozzle 521 .

According to the structure of the above (5), it is expected that the ammonia fuel injected by the first ammonia injection nozzle 521 can cool the flame heater 56 and suppress the temperature rise of the flame heater 56 .

(6) In some embodiments, in any of the structures (1) to (5) above, the ammonia fuel supplied to the first ammonia injection nozzle 521 may be liquid ammonia fuel.

According to the structure of the above (6), the heat of vaporization of the liquid ammonia fuel injected from the first ammonia injection nozzle 521 can be used to cool the flame retardant 56 and the like. Thereby, the temperature rise of the flame-retaining device 56 etc. can be suppressed.

(7) In some embodiments, any one of the structures (1) to (6) above may be provided with a second ammonia injection nozzle 522 for injecting ammonia fuel downstream of the flame retainer 56 .

According to the structure of (7) above, the ammonia fuel injected from the second ammonia injection nozzle 522 can be diffused and burned.

(8) In some embodiments, any one of the structures (1) to (7) above may be provided with a protruding portion 57 connected to the flame holder 56 and protruding toward the upstream side of the flame keeper 56 .

According to the structure of the above (8), the temperature rise of the heat protector 56 can be suppressed by convection cooling the protrusion 57 .

(9) In some embodiments, any one of the structures (1) to (8) above may be equipped with a temperature detection sensor (temperature sensor 96) that detects the metal temperature of the combustion air nozzle 54.

According to the structure of the above (9), the metal temperature of the combustion air nozzle 54 can be controlled.

(10) In some embodiments, any one of the structures (1) to (9) above may be provided with an ignition detection sensor 98 for detecting ignition inside the combustion air nozzle 54 .

According to the structure of (10) above, even if a part of the premixed fuel ignites inside the combustion air nozzle 54, the ignition can be detected, so that the flow rate to the inside of the ammonia combustion burner (ammonia burner 51) can be reduced. Risk of flashback.

(11) The boiler 10 according to at least one embodiment of the present invention is provided with a furnace 11 including a furnace wall 101, and an ammonia combustion burner (ammonia combustion burner) having any one of the structures (1) to (10) provided on the furnace wall 101. Burner 51).

According to the structure of the above (11), the NOx emission amount from the boiler 10 equipped with the ammonia combustion burner (ammonia burner 51) can be suppressed.

(12) The boiler 10 according to at least one embodiment of the present invention is provided with a furnace 11 including a furnace wall 101, and an ammonia combustion burner (ammonia combustion burner) having any one of the structures (1) to (10) provided on the furnace wall 101. The burner 51) is another fuel burner (burner 21) that is provided at a different position from the ammonia combustion burner (ammonia burner 51) on the furnace wall 101 and burns fuel other than ammonia fuel.

According to the structure (12) above, the NOx emission amount from the boiler 10 can be suppressed.

(13) The boiler 10 according to at least one embodiment of the present invention is provided with a furnace 11 including a furnace wall 101, and an ammonia combustion burner (ammonia combustion burner) having any one of the structures (1) to (9) provided on the furnace wall 101. The burner 51), an ignition detection sensor 98 that detects ignition inside the combustion air nozzle 54, controls the injection amount of ammonia fuel injected by the first ammonia injection nozzle 521 based on the detection result of the ignition detection sensor 98 control device 900. The control device 900 includes an injection amount calculation unit 902 that calculates an injection amount of ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the ignition detection sensor 98 , and an injection amount calculation unit 902 that adjusts the injection amount to The adjustment unit 95 of the calculated injection amount.

According to the structure of (13) above, the risk of backfire inside the ammonia combustion burner (ammonia burner 51) can be reduced.

(14) The boiler 10 according to at least one embodiment of the present invention is provided with a furnace 11 including a furnace wall 101, and an ammonia combustion burner (ammonia combustion burner) having any one of the structures (1) to (9) provided on the furnace wall 101. Burner 51), a control device 900 that controls the injection amount of ammonia fuel injected from the first ammonia injection nozzle 521. The ammonia fuel supplied to the first ammonia injection nozzle 521 is liquid ammonia. The ammonia combustion burner (ammonia burner 51) is equipped with a temperature sensor 96 that detects the temperature of the metal. The control device 900 includes an injection amount calculation unit 902 that calculates the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the temperature sensor 96, and adjusts the injection amount to a value determined by the injection amount calculation unit 902. The adjustment part 95 of the calculated injection amount.

According to the structure of the above (14), the metal temperature of the ammonia combustion burner (ammonia burner 51) can be suppressed, thereby suppressing the occurrence of burning loss.

(15) The operating method of the boiler 10 according to at least one embodiment of the present invention is an operating method of the boiler 10 supplied with ammonia fuel. The boiler 10 includes: a furnace 11 including a furnace wall 101, an ammonia combustion burner (ammonia burner 51) having any one of the structures (1) to (8) provided on the furnace wall 101, and an air nozzle for detecting combustion. 54 has an internal fire detection sensor 98 . The operating method of the boiler 10 according to at least one embodiment of the present invention includes step S10 of calculating the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 821 based on the detection result of the ignition detection sensor 98, and adjusting the injection amount. Step S20 is performed based on the injection amount calculated in step S10.

According to the structure of (15) above, the risk of backfire inside the ammonia combustion burner (ammonia burner 51) can be reduced.

(16) The operating method of the boiler 10 according to at least one embodiment of the present invention is an operating method of the boiler 10 supplied with ammonia fuel. The boiler 10 includes a furnace 11 including a furnace wall 101, and an ammonia combustion burner (ammonia burner 51) provided on the furnace wall 101 having any one of the structures (1) to (9) above. The ammonia fuel supplied to the first ammonia injection nozzle 521 is liquid ammonia. The ammonia combustion burner (ammonia burner 51) is equipped with a temperature sensor 96 that detects the temperature of the metal. The operation method of the boiler 10 according to at least one embodiment of the present invention includes step S50 of calculating the injection amount of the ammonia fuel injected from the first ammonia injection nozzle 521 based on the detection result of the temperature sensor 96, and adjusting the injection amount to Step S60 is performed to calculate the injection amount calculated in step S50.

According to the structure of the above (16), the metal temperature of the ammonia combustion burner (ammonia burner 51) can be suppressed, thereby suppressing the occurrence of burning loss.

1: Boiler system 10: Boiler 11:Stove 20,50: Combustion device 21:Burner 51: Ammonia burner (ammonia combustion burner) 51A: No. 1 ammonia burner 51B: The second ammonia burner 54:Combustion air nozzle 54a: opening 56,56A,56B: Flame protector 57:Protrusion 101: stove wall 521: The first ammonia injection nozzle 522: The second ammonia injection nozzle 541:Flow path 542:Flow path 625:Partition wall

[Fig. 1] A schematic structural diagram showing a boiler system including a boiler using ammonia fuel and a fuel other than ammonia fuel as a main fuel according to this embodiment. [Fig. 2] A schematic diagram showing the structure of the first ammonia burner. [Fig. 3] Schematic diagram illustrating the contact state between ammonia fuel and combustion air. [Fig. 4] A graph illustrating the air ratio at the contact surface between ammonia fuel and combustion air. [Fig. 5] A schematic diagram showing the structure of the second ammonia burner. [Fig. 6] A schematic diagram showing the structure of the first ammonia burner provided with a protruding portion. [Fig. 7A] A cross-sectional view schematically showing an example of the structure of a pressure spray nozzle. [Fig. 7B] A schematic diagram of a back plate disposed inside the pressure spray nozzle shown in Fig. 7A. [Fig. 8] A cross-sectional view schematically showing an example of the structure of a two-fluid spray nozzle. [Fig. 9] A diagram illustrating adjustment of the ammonia injection amount from the first ammonia injection nozzle. [Fig. 10] A flowchart showing a process flow for controlling the injection amount of ammonia fuel injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor. [Fig. 11] A flowchart showing a process flow for controlling the injection amount of ammonia fuel injected from the first ammonia injection nozzle based on the detection result of the temperature sensor.

51: Ammonia burner (ammonia combustion burner)

51A: No. 1 ammonia burner

52h: Jet hole

54:Combustion air nozzle

54a: opening

54i: Inner surface

56,56A: Flame protector

521: The first ammonia injection nozzle

522: The second ammonia injection nozzle

541:Flow path

542:Flow path

625:Partition wall

625a: Inner peripheral surface

625b: Outer peripheral surface

Ax: central axis

Claims (16)

An ammonia combustion burner is an ammonia combustion burner used to burn ammonia fuel in a boiler. It has: Combustion air nozzle, which is used to spray combustion air; a first ammonia injection nozzle arranged inside the combustion air nozzle for injecting the ammonia fuel into the combustion air nozzle; and a flame retainer arranged downstream of the first ammonia injection nozzle, The combustion air nozzle is configured to inject a portion of the combustion air, a premixed fuel portion of the ammonia fuel previously injected from the first ammonia injection nozzle, and a remaining portion of the combustion air. The ammonia combustion burner as described in claim 1, wherein, The combustion air nozzle has an opening for ejecting combustion air, The aforementioned opening forms a gap with the outer edge of the aforementioned inflammation device, The gap is a passage for causing at least a part of the partially premixed fuel and the remaining part of the combustion air to be ejected from the gap. The ammonia combustion burner as described in claim 1 or 2 has: A partition wall separates the flow path of the partial premixed fuel from the flow path of the remaining portion of the combustion air. The ammonia combustion burner as described in claim 1 or 2, wherein, The aforementioned inflammation-preserving device is a diffusion-type or swirl-type inflammation-preserving device. The ammonia combustion burner as described in claim 1 or 2, wherein, At least a part of the flame retainer is located in an injection range of the ammonia fuel injected by the first ammonia injection nozzle. The ammonia combustion burner as described in claim 1 or 2, wherein, The ammonia fuel supplied to the first ammonia injection nozzle is liquid ammonia. The ammonia combustion burner as described in claim 1 or 2 has: A second ammonia injection nozzle is used to inject the ammonia fuel downstream of the flame retainer. The ammonia combustion burner as described in claim 1 or 2 has: The protruding portion is connected to the aforementioned flame-preserving device and protrudes toward the upstream side of the aforementioned inflammation-preserving device. The ammonia combustion burner as described in claim 1 or 2 has: A temperature detection sensor detects the metal temperature of the combustion air nozzle. The ammonia combustion burner as described in claim 1 or 2 has: An ignition detection sensor detects ignition inside the combustion air nozzle. A boiler having: A stove containing a stove wall; and The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace. A boiler having: A stove containing a stove wall; The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace; and Other fuel burners are provided on the furnace wall at a different position from the ammonia combustion burner to burn fuels other than the ammonia fuel. A boiler having: A stove containing a stove wall; The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace; A fire detection sensor that detects fire inside the aforementioned combustion air nozzle; and a control device that controls the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor, The aforementioned control device has: an injection amount calculation unit that calculates the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor; and The adjustment unit adjusts the injection amount to become the injection amount calculated by the injection amount calculation unit. A boiler having: A stove containing a stove wall; The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace; and a control device that controls the injection amount of the ammonia fuel injected from the first ammonia injection nozzle, The ammonia fuel supplied to the first ammonia injection nozzle is liquid ammonia, The aforementioned ammonia combustion burner is equipped with a temperature sensor for detecting metal temperature. The aforementioned control device has: an injection amount calculation unit that calculates the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the temperature sensor; and The adjustment unit adjusts the injection amount to become the injection amount calculated by the injection amount calculation unit. A method of operating a boiler is an operating method of a boiler supplied with ammonia fuel, The aforementioned boiler contains: A stove containing a stove wall; The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace; and A fire detection sensor that detects fire inside the aforementioned combustion air nozzle, And have: The step of calculating the injection amount of the ammonia fuel before being injected from the first ammonia injection nozzle based on the detection result of the ignition detection sensor; and The injection amount is adjusted to the injection amount calculated in the calculating step. A method of operating a boiler is an operating method of a boiler supplied with ammonia fuel, The aforementioned boiler contains: A stove containing a stove wall; and The ammonia combustion burner described in claim 1 or 2 is located on the wall of the aforementioned furnace, The ammonia fuel supplied to the first ammonia injection nozzle is liquid ammonia, The aforementioned ammonia combustion burner is equipped with a temperature sensor for detecting metal temperature. And have: The step of calculating the injection amount of the ammonia fuel before injecting it from the first ammonia injection nozzle based on the detection result of the temperature sensor; and The injection amount is adjusted to the injection amount calculated in the calculating step.

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