TW202334583A - Burner and boiler equipped with same, and burner operation method - Google Patents

Abstract

Provided is a burner capable of increasing the co-firing rate of ammonia fuel when co-firing the ammonia fuel and pulverized fuel. The present invention comprises: an inner cylinder nozzle (61) that extends along a central axis (CL); an outer cylinder nozzle (62) that extends along the central axis (CL) and is disposed so as to cover the inner cylinder nozzle (61), and supplies pulverized fuel and primary air into a furnace; a pulverized fuel flame stabilizer (71) for stabilizing the flame of the pulverized fuel supplied from the outer cylinder nozzle (62); and a concentrator (69) that is disposed inside the outer cylinder nozzle (62) and concentrates the pulverized fuel on the pulverized fuel flame stabilizer (71) side. Ammonia fuel is supplied to the inner cylinder nozzle (61).

Description

Burners and boilers equipped with them and methods of operation of burners

The present invention, for example, relates to a burner, a boiler equipped with the burner, and an operation method of the burner, in which pulverized solid fuel is combusted with ammonia fuel.

A large boiler such as a power generation boiler has a hollow furnace installed in a vertical direction, and a plurality of burners are arranged on the wall of the furnace. In addition, a large boiler has a flue connected vertically above the furnace, and a heat exchanger for generating steam is disposed in the flue. Then, the burner injects a mixture of fuel and air (oxidizing gas) into the furnace to form a flame and generate combustion gas that flows to the flue. A heat exchanger is provided in an area where combustion gas flows, and water or steam flowing in a heat transfer tube constituting the heat exchanger is heated to generate superheated steam.

As a burner used in a boiler, it is examined that pulverized coal and ammonia fuel are mixed and burned, or pulverized coal is exclusively burned and ammonia fuel is exclusively burned (for example, Patent Document 1). [Prior technical literature] [Patent Document]

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

[Problem to be solved by the invention]

However, Patent Document 1 discloses coaxially mixed combustion of pulverized coal and ammonia fuel, but does not examine at all the increase in the mixed combustion rate of ammonia fuel. For example, in the structure of Patent Document 1, if the mixed combustion rate of the ammonia fuel is increased, the flame-retaining property of the pulverized coal is reduced and the mixed combustion with the ammonia fuel cannot be continued.

The present invention was made in view of the above-mentioned circumstances, and its object is to provide a burner that can increase the mixed combustion rate of ammonia fuel when ammonia fuel and pulverized fuel are mixed and burned, a boiler equipped with this, and a method of operating the burner. [Technical means to solve problems]

A burner of one aspect of the present invention is provided with: an inner cylinder nozzle extending along a central axis; and an outer cylinder nozzle extending along the central axis and disposed to cover the inner cylinder nozzle and supply fine powder fuel and primary air. into the furnace; a pulverized fuel flame retainer, which maintains the flame of the pulverized fuel supplied from the outer cylinder nozzle; and a concentrator, which is provided inside the outer cylinder nozzle and supplies the pulverized fuel to the pulverized fuel The ammonia fuel is supplied to the inner cylinder nozzle or the outer cylinder nozzle by concentrating on the incubator side.

An operating method of a burner according to one aspect of the present invention. The burner is provided with: an inner cylinder nozzle extending along a central axis; and an outer cylinder nozzle extending along the central axis and disposed to cover the inner cylinder nozzle, The fine powder fuel and primary air are supplied into the furnace; the fine powder fuel flame retainer is used to maintain the flame of the aforementioned fine powder fuel supplied from the aforementioned outer cylinder nozzle; and the concentrator is provided inside the aforementioned outer cylinder nozzle to The aforementioned fine powder fuel is concentrated toward the side of the aforementioned fine powder fuel inflammator, and the operation method is to supply ammonia fuel to the aforementioned inner cylinder nozzle or the aforementioned outer cylinder nozzle. [Effects of the invention]

According to the burner of the present invention, the mixed combustion rate of ammonia fuel can be increased.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In addition, the present invention is not limited to this embodiment, and when there are plural embodiments, it also includes a structure in which the respective embodiments are combined. In the following description, upper or upper means the upper side in the vertical direction, and lower or lower means the lower side in the vertical direction. These vertical directions are not exact and contain errors.

[First Embodiment] FIG. 1 shows a boiler 10 using fine powder fuel and/or ammonia (NH ₃ ) fuel as a main fuel according to this embodiment. In the boiler 10 of this embodiment, pulverized solid fuel and ammonia fuel are burned with a burner, and the heat generated by the combustion can be used to exchange heat with water supply or steam to generate superheated steam. As solid fuel, biomass fuel, coal, etc. are used.

The boiler 10 has a furnace 11, a combustion device 20, 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 the fine powder fuel is circulated between the heat transfer tubes. The water or steam inside is recovered through heat exchange, and the temperature rise of the furnace wall 101 is suppressed.

The combustion device 20 is arranged in the lower area of the stove 11 . In this embodiment, the combustion device 20 has a plurality of burners 21A, 21B, 21C, 21D, 21E, and 21F installed on the furnace wall 101 (hereinafter simply referred to as "burners" when these burners are not distinguished. Device 21"). The burners 21 are arranged at equal intervals along the furnace wall 101 in the furnace circumferential direction (for example, the opposing furnace walls 101 are arranged to face each other in the furnace circumferential direction to achieve opposing combustion). , arrange complex segments along the vertical direction. 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.

The burners 21A, 21B, 21C, 21D, 21E, and 21F each pass through a plurality of pulverized fuel supply pipes 22A, 22B, 22C, 22D, 22E, and 22F (hereinafter referred to as the pulverized fuel supply pipes without distinguishing them). is the "fine fuel supply pipe 22") and is connected to a plurality of grinders (pulverizers) 31A, 31B, 31C, 31D, 31E, and 31F (hereinafter referred to as "grinders" without distinguishing these grinders). Crusher 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 grinder. The solid fuel pulverized by the cooperative operation of the pulverizing roller and the pulverizing platform is transported to the classifier ( Illustration omitted). In the classifier, the fine powder fuel is classified into fine powder fuel having a particle size smaller than or equal to the particle size suitable for combustion by the burner 21 and briquette fuel larger than the particle size. 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 briquette fuel that has not passed through the classifier falls to the crushing platform due to its own weight inside the grinder 31 and is crushed again.

A wind box (wind regulator) 23 is provided outside the furnace 11 where the burner 21 is installed, and one end of an air duct (air passage) 24 is connected to the wind box 23 . 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 blower 32 is heated by the air preheater 42 provided in the air duct 24, and is supplied to the burner 21 as secondary air (combustion air, oxidizing gas) through the air box 23. And put into the inside of the stove 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 as heat exchangers for recovering the heat of the combustion gas (hereinafter simply referred to as "superheater 102" when these superheaters are not distinguished), The reheaters 103A and 103B (hereinafter simply referred to as the "reheater 103" when these reheaters are not distinguished) and the economizer 104 allow the combustion gas generated in the furnace 11 to mix with the inside of each heat exchanger. Heat exchange occurs between circulating water supplies or steam. 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 to supply The primary air to the attritor 31 or the secondary air supplied to the burner 21 is heated, whereby heat is further recovered 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.

When mixed combustion of pulverized fuel and ammonia fuel is performed in the boiler 10, if a plurality of grinders 31 are driven, the pulverized and classified pulverized fuel will be supplied to the boiler 10 through the pulverized fuel supply pipe 22 together with primary air. Burner 21. Furthermore, the secondary air heated by the air preheater 42 is supplied from the air duct 24 through the air box 23 to the burner 21 . The burner 21 blows the pulverized fuel mixture obtained by mixing pulverized fuel and primary air into the furnace 11 and blows the secondary air into the furnace 11 . The fine powder fuel mixture blown into the furnace 11 is ignited and reacts with the secondary air to form a flame. A flame is formed in the lower region of the furnace 11 , causing high-temperature combustion gas to rise in the furnace 11 and flow into the combustion gas passage 12 . In addition, in this embodiment, air is used as the oxidizing gas (primary air, secondary air), but the proportion of oxygen may be more or less than that of air. The ratio of the amount of oxygen to the amount of supplied fuel may be Adjust to an appropriate range to achieve stable combustion in the stove 11.

Furthermore, a plurality of additional air ports (AA ports) 25 for supplying additional air (AA: Additional Air) for combustion into the furnace 11 are provided above the installation position of the burner 21 of the furnace 11 . The additional air passage 25 is connected to an end portion of an additional air passage (AA passage) 26 branched from the air duct 24. Part of the air supplied from the blower 32 is used as additional air for combustion through the additional air passage 26. Supply to additional air vent 25.

In the area A inside the furnace 11 shown in FIG. 1 (the area corresponding to the installation range in the height direction of the wind box 23), a flame is formed by the combustion of the mixture of primary air and fine powder fuel and the secondary air. Here, the air ratio in the area A is equal to or less than 1. Specifically, the amount of air supplied to the burner 21 (the total amount of primary air and secondary air) is made smaller than the amount of air supplied to the burner 21 . The theoretical air amount of the fuel amount is set in such a way that the area A and area B (the area from the uppermost part of the burner 21 to the lowermost part of the extra air port 25) inside the furnace 11 become In a reducing environment, nitrogen oxides (NOx) generated by combustion will be reduced inside the furnace 11 . Thereafter, in area C (the area above the lowermost part of the additional air port 25), additional air for combustion is supplied from the additional air port 25 to the combustion gas after reducing NOx to complete the combustion. However, from area A and The reduction effect of area B will reduce the production of NOx.

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 after heat exchange with the primary air and secondary air by the air preheater 42, it is further discharged to the gas channel 41, and dust and the like are removed by the dust collection device 44. After the sulfur oxides are removed by the desulfurization device 46, they 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.

The boiler 10 is provided with an ammonia supply source 50 . In the ammonia supply source 50, ammonia is stored in a gas or liquid state as ammonia fuel. Ammonia fuel is supplied from the ammonia supply source 50 to each burner 21 . When ammonia gas is used in the burner 21 , the ammonia fuel is stored as gas in the ammonia supply source 50 , or is stored as liquid ammonia and vaporized on the way to the burner 21 . When liquid ammonia is used in the burner 21, it is preferable to store liquid ammonia in the ammonia supply source 50.

The switching between fine powder fuel and ammonia fuel can be done manually by the operator or by instructions from the control unit. The control unit is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. Then, a series of processing to realize various functions is, for example, stored in a memory medium in the form of a program. The CPU reads the program into RAM, etc., and executes information processing and calculation processing, thereby realizing various functions. In addition, the program can also be applied to a form that is installed in ROM or other memory media in advance, a form that is provided in a state of being stored in a memory medium that can be read by a computer, a form that is transmitted through wired or wireless communication means, etc. Memory media that can be read by computers refers to magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc.

In Figure 2, a burner 21 is shown. The burner 21 can perform mixed combustion of fine powder fuel and ammonia gas (ammonia fuel). The burner 21 includes an inner cylinder nozzle 61 extending along the central axis CL, and an outer cylinder nozzle 62 provided to cover the inner cylinder nozzle 61 . An oil nozzle 63 is provided on the inner peripheral side of the inner cylinder nozzle 61 . Each of the nozzles 61, 62, and 63 has a common central axis CL, has a circular cross section, and is made of metal, for example.

The inner cylinder nozzle 61 is supplied with ammonia gas and air (combustion air), and sprays the mixed gas into the furnace 11 . Ammonia gas is supplied from the ammonia supply source 50 in Fig. 1 .

An ammonia flame retainer 67 is provided at the front end of the inner cylinder nozzle 61 between the inner cylinder nozzle 61 and the oil nozzle 63 . The ammonia flame retainer 67 has, for example, a fan blade shape, and imparts rotation about the central axis CL to the mixed gas of ammonia gas and air. The ammonia flame retainer 67 maintains the flame of the ammonia gas injected from the inner cylinder nozzle 61 .

In the outer cylinder nozzle 62, fine powder fuel and primary air guided from the attritor 31 (see FIG. 1) are supplied. In the outer cylinder nozzle 62, a constriction part 68 and a concentrator 69 are provided.

The restricting portion 68 extends in the circumferential direction on the inner wall of the outer cylinder nozzle 62 and restricts the flow path in the outer cylinder nozzle 62 by a shape that bulges toward the inner circumference side (center axis CL side). For example, it includes an upstream inclined portion 68a located on the upstream side and inclined toward the inner circumferential side, and a downstream inclined portion 68b connected to the apex of the upstream inclined portion 68a and inclined toward the outer circumferential side toward the downstream side. The constriction portion 68 imparts a velocity component toward the central axis CL to the flow.

The concentrator 69 is located on the downstream side of the constriction portion 68, is extended and fixed in the circumferential direction on the outer wall of the oil nozzle 63, and has a shape that bulges toward the outer circumference. For example, it includes an upstream inclined portion 69a located on the upstream side and inclined toward the inner circumferential side, a cylindrical portion 69c connected to the apex of the upstream inclined portion 68a and extending parallel to the central axis CL, and a cylindrical portion 69c connected to the cylindrical portion 69c. The downstream side inclined portion 69b is the downstream side inclined portion 69b that is inclined toward the outer circumferential side toward the downstream side.

The concentrator 69 expands the flow path narrowed by the constriction portion 68 to impart a velocity component to the flow in the direction (radial direction) toward the outer cylinder nozzle 62 side. The inertial force of the fine powder fuel is greater than that of primary air, so it is concentrated on the inner wall side of the outer cylinder nozzle 62 through the constriction part 68 and the concentrator 69, forming a high concentration area of the fine powder fuel.

A pulverized fuel flame retainer 71 serving as a baffle is provided at the front end and outer peripheral side of the outer cylinder nozzle 62 . The pulverized fuel flame retainer 71 has an annular shape when the outer cylinder nozzle 62 is viewed from the front. The flow of the secondary air flowing in the secondary air flow path 73 is partially blocked by the flame retainer 71 for fine powder fuel, and a flame retaining area is formed on the downstream side thereof. Thereby, the flame of the fine powder fuel supplied from the outer cylinder nozzle 62 is maintained.

The oil nozzle 63 is supplied with oil fuel from an oil fuel supply source (not shown). Oil fuel is used when starting the burner 21. After starting, the supply of oil fuel is stopped and a trace amount of cooling air is supplied.

The secondary air flow path 73 is provided to cover the outer cylinder nozzle 62 . A tertiary air flow path 74 is provided on the outer peripheral side of the secondary air flow path 73 so as to cover the secondary air flow path 73 . In the tertiary air flow path 74, a rotator 74a that imparts rotation to the tertiary air is provided.

Next, the operation of the burner 21 having the above structure will be described. First, the burner 21 is started by supplying oil fuel from the oil nozzle 63 . The oil fuel injected into the furnace 11 from the oil nozzle 63 forms a flame together with the air supplied from the inner cylinder nozzle 61 to heat up the furnace 11 . The flame of the oil fuel is maintained by the ammonia flame retainer 67. In other words, the ammonia heat preservation device 67 is also used to heat the oil fuel during starting.

Then, when the temperature inside the furnace 11 rises to a predetermined temperature and startup is completed, the supply of oil fuel is stopped. When the supply of oil fuel is stopped, a trace amount of air flows from the oil nozzle 63 for cooling the oil nozzle 63 .

After a predetermined time has elapsed since starting the burner, the supply of finely divided fuel and ammonia gas is performed as follows.

The fine powder fuel is slowly supplied from the outer cylinder nozzle 62 together with the primary air, thereby forming a flame caused by the fine powder fuel. The finely divided fuel forms a high-concentration area on the inner wall side of the outer cylinder nozzle 62 by the constrictor 68 and the concentrator 69 . The flame of the pulverized fuel is maintained by the pulverized fuel flame retainer 71 provided in the outer cylinder nozzle 62 , and is controlled by the secondary air supplied from the secondary air flow path 73 and the tertiary air supplied from the tertiary air flow path 74 Burn in stages.

Ammonia gas is gradually supplied from the ammonia supply source 50 (see FIG. 1 ) together with air into the inner cylinder nozzle 61 , and is introduced to the ammonia flame retainer 67 in a premixed state. The over-rotating premixed gas provided by the ammonia flame retainer 67 moves straight along the central axis CL to form a premixed flame of ammonia gas. In this way, the flame of the ammonia gas is maintained by the ammonia flame retainer 67, and is mixed and burned with the fine powder fuel supplied from the outer cylinder nozzle 62.

The functions and effects of this embodiment described above are as follows. By the concentrator 69 provided inside the outer cylinder nozzle 62, the pulverized fuel is concentrated toward the inner wall side of the flame retainer 71 for pulverized fuel. Thereby, the flame-preserving effect of the flame-preserving device 71 for fine powder fuel is made more stable. Furthermore, the ammonia gas is supplied to the inner cylinder nozzle 61, whereby the ammonia gas is supplied to the vicinity of the flame of the pulverized fuel that has been intensified by using the concentrator 69 and the pulverized fuel flame retainer 71, and more specifically to the inside, This can stabilize the combustion of ammonia gas and increase the mixed combustion rate of ammonia fuel. For example, when multiple fuels are burned simultaneously with a single burner, the mixed combustion rate of ammonia fuel can be increased to more than 50%.

Ammonia gas and air are supplied to the inner cylinder nozzle 61 to perform premixed combustion, thereby stabilizing the flame. In addition, the ammonia flame retainer 67 provided at the front end of the inner cylinder nozzle 61 makes the flame of the ammonia gas more stable. Thereby, the mixed combustion rate of the ammonia fuel can be increased.

Furthermore, in this embodiment, a control valve (not shown) for controlling the air flow rate supplied to the inner tube nozzle 61 is provided, and the opening of the control valve may be controlled by the control unit. At this time, the control unit obtains the flow rates of ammonia gas, air, pulverized fuel, and primary air from a sensor (not shown), and calculates the mixed combustion rate (current value) of the ammonia fuel. Then, the control unit adjusts the opening of the control valve to reduce the air flow rate in response to the increase in the mixed combustion rate of the ammonia fuel. By controlling in this way, even if the mixed combustion rate of the ammonia fuel increases and there is a risk that it will be difficult to maintain the flame of the fine powder fuel, the air flow rate can be reduced in response to the increase in the ammonia fuel, thereby reducing the flow rate from the inner cylinder. The flow rate of the premixed fuel flowing out of the nozzle 61. Thereby, the ignition hindrance of the fine powder fuel can be avoided as much as possible, the flame of the fine powder fuel can be maintained, and the mixed combustion rate of the ammonia fuel can be increased.

[Second Embodiment] Next, a second embodiment of the present invention will be described using FIGS. 3A and 3B. In this embodiment, in addition to omitting the oil nozzle 63 of the first embodiment, the ammonia gas injection position is also different. In the following description, the same structures as those in the first embodiment are assigned the same reference numerals and their descriptions are omitted, and different structures are mainly described.

As shown in FIG. 3A , the burner 21 of this embodiment is provided with the inner cylinder nozzle 61 at the position closest to the central axis CL. Therefore, the oil nozzle 63 of the first embodiment is not provided inside the inner cylinder nozzle 61 . The end of the inner cylinder nozzle 61 on the furnace 11 side (the right end in FIG. 3A ) is closed, and ammonia gas will not be ejected therefrom. Ammonia gas is supplied to the inner cylinder nozzle 61 from the ammonia supply source 50 shown in FIG. 1 . However, unlike the first embodiment, only ammonia gas is supplied to the inner cylinder nozzle 61, and air is not supplied.

As shown in FIG. 3B , a plurality of slits (ammonia gas ejection holes) 80 are formed in the concentrator 69 . The slits 80 form vertically elongated flow paths in a radial shape in the radial direction. There are four slits 80 in this embodiment, but the number is not particularly limited and may be two or more or three or more. Each gap 80 is connected with the inner cylinder nozzle 61 for ammonia gas to circulate. Each slit 80 is formed in the downstream inclined portion 68b of the concentrator 69 as shown in FIG. 3A , and injects ammonia gas in the direction along the central axis CL as shown by arrows. Ammonia gas is injected into the outer cylinder nozzle 62 through the gap 80 . The primary air flowing in the outer cylinder nozzle 62 is used as the combustion air for the ammonia gas.

According to this embodiment, the following functions and effects are achieved. Ammonia gas is sprayed into the outer cylinder nozzle 62 from each slit 80 formed in the concentrator 69, so that it can form a flame together with the fine powder fuel, thereby increasing the mixed combustion rate of the ammonia fuel.

The ammonia gas is ejected from the gap 80 along the central axis CL without spreading in the radial direction as much as possible. Therefore, the mixing with the fine powder fuel concentrated toward the inner wall side of the outer cylinder nozzle 62 by the concentrator 69 will be delayed, which can reduce the NOx.

Moreover, in this embodiment, ammonia gas is sprayed from the slit 80 along the central axis CL, but it may be changed as shown in FIGS. 4A and 4B . Specifically, the direction of the ammonia gas ejection is changed. The slit 80' is formed in a direction such that the ammonia gas is ejected toward the outer circumferential side (radial direction) while being inclined with respect to the central axis CL, as indicated by arrows in FIGS. 4A and 4B.

The ammonia gas is ejected from the gap 80' at an angle to the central axis CL toward the outer peripheral side, whereby the ammonia gas is diffused on the inner wall side of the outer cylinder nozzle 62 and condensed toward the inner wall side of the outer cylinder nozzle 62 by the concentrator 69. Micronized fuel is mixed to promote combustion.

[Third Embodiment] Next, a third embodiment of the present invention will be described using FIG. 5 . This embodiment is different from the second embodiment in that a distributor 82 is added. Since the other structures are the same, the same reference numerals are used and description thereof is omitted.

As shown in FIG. 5 , a ring-shaped distributor 82 is provided inside the front end of the outer cylinder nozzle 62 . The distributor 82 is provided so as to surround the downstream end of the downstream inclined portion 69b of the concentrator 69 . The distributor 82 divides the flow path in the outer cylinder nozzle 62 into an inner flow path 62a and an outer flow path 62b.

The inner flow path 62a and the outer flow path 62b of the outer cylinder nozzle 62 are separated by the concentrator 69 to form the inner flow path 62a through which primary air mainly flows and the outer flow path 62b through which concentrated pulverized fuel mainly flows. Thereby, the primary air flowing in the inner flow path 62a can be used for the combustion of ammonia gas, and the ignition of the fine powder fuel can be promoted by the concentrated fine powder fuel flowing in the outer flow path 62b.

Moreover, in this embodiment, as shown in FIG. 5 , the ejection direction of ammonia gas is a direction that is inclined with respect to the central axis CL and ejects toward the outer peripheral side as shown in FIG. 4A . However, the present invention is not limited to this. For example, as shown in FIG. 3A , ammonia gas may be sprayed from the slit 80 along the central axis CL.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described using FIGS. 6A to 6C . In the second embodiment, the ammonia gas is blown out from the inner peripheral side of the outer cylinder nozzle 62 , but this embodiment is different in that the ammonia gas is blown out from the inner wall side of the outer cylinder nozzle 62 . In the following description, the same structures as those in the second embodiment are assigned the same reference numerals and their descriptions are omitted, and different structures are mainly described.

As shown in FIG. 6A , ammonia gas is not supplied from the inner cylinder nozzle 61 . The inner cylinder nozzle 61 basically flows a trace amount of cooling air, but if necessary, is used as an oil nozzle during startup.

A plurality of circumferential concentrators 85 are provided on the inner wall of the outer cylinder nozzle 62 . Each circumferential concentrator 85 is located on the outer peripheral side of the downstream inclined portion 69b of the concentrator 69 .

As shown in FIG. 6B , each circumferential concentrator 85 is installed along the circumferential direction of the inner wall of the outer cylinder nozzle 62 with a predetermined interval in the circumferential direction. The pulverized fuel concentrated by the concentrator 69 is restricted and flows between the adjacent circumferential direction concentrators 85 .

In FIG. 6C , two circumferential direction concentrators 85 are shown as an example. In the figure, the upper side shows the outer peripheral side of the outer cylinder nozzle 62 , and the lower side shows the inner peripheral side of the outer cylinder nozzle 62 . As shown in FIG. 6C , an ammonia gas ejection hole 85 a for ejecting ammonia gas is provided at the front end (downstream end) of the circumferential direction concentrator 85 . The ammonia gas supply pipe 87 is connected to the circumferential direction concentrator 85 through the tubular mounting part 85b (see FIGS. 6A and 6B ). Ammonia gas is supplied to the circumferential concentrator 85 from the ammonia supply source 50 (see FIG. 1 ) through the ammonia gas supply pipe 87 .

As shown in FIG. 6C , the circumferential concentrator 85 has a rhombus shape when viewed from the inner circumferential side of the outer cylinder nozzle 62, gradually widens from the upstream end 85c, and gradually narrows from the intermediate position 85d toward the downstream end 85e. A plurality of ammonia gas ejection holes 85a are formed from the intermediate position 85d to the downstream side 85f of the downstream end 85e. In addition, the bottom surface 85g, which is the surface on the inner circumferential side of the circumferential direction concentrator 85, is closed.

According to this embodiment, the following functions and effects are achieved. The concentrator 69 is provided on the outer wall of the inner cylinder nozzle 61 , whereby the fine powder fuel is concentrated toward the inner wall side of the outer cylinder nozzle 62 . Then, a plurality of circumferential concentrators 85 are provided at predetermined intervals in the circumferential direction on the inner wall at the front end of the outer cylinder nozzle 62, thereby partially reducing the width of the flow path in the circumferential direction and concentrating the fine fuel in the circumferential direction. Then, the ammonia gas is ejected from the ammonia gas ejection hole 85a provided in the circumferential direction concentrator 85, and is mixed with the fine powder fuel concentrated in the circumferential direction to promote combustion.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described using FIGS. 7A and 7B. In the first embodiment, ammonia gas is used, but this embodiment is different in that liquid ammonia is used. In the following description, the same structures as those in the first embodiment are assigned the same reference numerals and their descriptions are omitted, and different structures are mainly described.

As shown in FIG. 7A , a liquid ammonia supply pipe 90 for injecting liquid ammonia is provided in the inner cylinder nozzle 61 . A plurality of liquid ammonia supply pipes 90 are provided at predetermined intervals around the central axis CL. Liquid ammonia is supplied from the ammonia supply source 50 (see FIG. 1 ) to the liquid ammonia supply pipe 90 . Air is supplied to the inner cylinder nozzle 61 .

In the liquid ammonia supply pipe 90, a liquid ammonia injection nozzle 92 is provided as shown in FIG. 7B. As shown in FIG. 7B , a liquid ammonia flow path is formed in the liquid ammonia injection nozzle 92 , and atomized liquid ammonia fuel is injected into the inner cylinder nozzle 61 from a plurality of injection holes 92 a. Through the liquid ammonia injection nozzle 92, liquid ammonia is sprayed with pressure spray. Liquid ammonia is injected from the liquid ammonia injection nozzle 92 of the liquid ammonia supply pipe 90 to the upstream side of the ammonia inflamator 67 .

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described using FIG. 8 . In the fifth embodiment, liquid ammonia is supplied. However, as a burner for burning liquid ammonia, liquid ammonia may be supplied to the oil nozzle 63 for injecting oil fuel that is also liquid. In this case, if a large amount of liquid ammonia is supplied into the furnace 11 from the central axis CL side of the burner 21, the temperature near the outlet of the burner 21 will drop due to the heat of vaporization, making it difficult to ignite. Therefore, in addition to the ammonia supplied from the oil nozzle 63 , a necessary amount of ammonia is preferably supplied from the outer peripheral side of the oil nozzle 63 , that is, from the ammonia supply pipe 95 provided in the tertiary air flow path 74 .

The ammonia supply pipes 95 are cylindrical members, and are arranged in plural numbers at appropriate intervals in the tertiary air flow path 74 in the circumferential direction. However, the shape, number, etc. of the ammonia supply pipes 95 are not limited as long as the fuel can be ignited and burned stably. Furthermore, the ammonia supplied to the ammonia supply pipe 95 may be liquid or gas.

According to this embodiment, the following functions and effects are achieved. Liquid ammonia is sprayed on the upstream side of the ammonia flame retainer 67 provided at the front end of the inner cylinder nozzle 61 . Thereby, the air supplied to the inner cylinder nozzle 61 will be mixed with the air supplied to the inner cylinder nozzle 61 on the upstream side of the ammonia flame retainer 67, and the liquid ammonia will be vaporized as much as possible in the ammonia flame retainer 67. The inflammation effect is more stable. Thereby, the mixed combustion rate of the ammonia fuel can be increased.

In each of the above embodiments, it has been explained that the boiler of the present invention uses solid fuel as fuel. As the solid fuel used in the boiler, coal, biomass fuel, petroleum coke (PC: Petroleum Coke) fuel, petroleum residue, etc. are used.

The burner described in each embodiment described above, the boiler equipped with the burner, and the operation method of the burner are as follows, for example.

A burner (21) according to one aspect of the present invention is provided with: an inner cylinder nozzle (61) extending along the central axis (CL); and an outer cylinder nozzle (62) extending along the central axis and arranged to cover The aforementioned inner cylinder nozzle supplies pulverized fuel and primary air into the furnace; the flame holder (71) for pulverized fuel, which maintains the flame of the aforementioned pulverized fuel supplied from the aforementioned outer cylinder nozzle; and the concentrator (69), It is provided inside the outer cylinder nozzle, concentrates the fine powder fuel toward the flame retainer side for the fine powder fuel, and supplies ammonia fuel to the inner cylinder nozzle or the outer cylinder nozzle.

The fine powder fuel is concentrated toward the side of the flame retardant for fine powder fuel by the concentrator located inside the outer cylinder nozzle. In this way, the flame-preserving effect of the flame-preserving device for micro-powder fuel is more stable. Furthermore, by supplying the ammonia fuel to the inner cylinder nozzle or the outer cylinder nozzle, the ammonia fuel is supplied to the vicinity of the flame of the pulverized fuel that has been inflamed using a concentrator and a flame holder for pulverized fuel, thereby increasing the amount of ammonia. Fuel mixture combustion rate.

In one aspect of the burner of the present invention, ammonia gas is used as the ammonia fuel, ammonia gas and air are supplied to the inner cylinder nozzle, and an ammonia flame retainer (67) is provided at the front end of the inner cylinder nozzle. This is used to maintain the flame of the ammonia gas supplied from the inner cylinder nozzle.

Ammonia and air are supplied to the inner cylinder nozzle to perform premixed combustion, thereby stabilizing the flame. In addition, the ammonia flame protector located in front of the inner barrel nozzle makes the ammonia flame more stable. Thereby, the mixed combustion rate of the ammonia fuel can be increased.

A burner according to one aspect of the present invention is provided with a control valve that controls the air flow rate supplied to the inner cylinder nozzle, and a control unit that controls the control valve. The control unit responds to an increase in the mixed combustion rate of the ammonia fuel. The control valve is controlled to reduce the flow rate of the air.

If the mixed combustion rate of the ammonia fuel increases, it may become difficult to maintain the flame of the fine powder fuel. Therefore, the air flow rate is reduced in response to the increase in ammonia fuel, thereby reducing the flow rate of the premixed fuel flowing out from the inner cylinder nozzle. Thereby, the ignition hindrance of the fine powder fuel can be avoided as much as possible, the flame of the fine powder fuel can be maintained, and the mixed combustion rate of the ammonia fuel can be increased.

In a burner of one aspect of the present invention, ammonia gas is used as the ammonia fuel, ammonia gas is supplied to the inner cylinder nozzle, the concentrator is provided on an outer wall of the inner cylinder nozzle, and the ammonia gas is provided in the concentrator. Gas ejection holes (80, 80') are used to inject the ammonia gas derived from the inner cylinder nozzle into the outer cylinder nozzle.

The concentrator is provided on the outer wall of the inner cylinder nozzle, whereby the finely divided fuel can be concentrated toward the inner wall side of the outer cylinder nozzle. The ammonia gas is ejected from the ammonia gas ejection hole formed in the concentrator into the outer cylinder nozzle, so it can form a flame together with the fine powder fuel and increase the mixed combustion rate of the ammonia fuel.

In the burner according to one aspect of the present invention, the ammonia gas ejection hole is formed in a direction in which the ammonia gas is ejected along the central axis.

The ammonia gas is ejected from the ammonia gas ejection hole along the central axis, thereby delaying the mixing with the fine powder fuel concentrated by the concentrator toward the inner wall side of the outer cylinder nozzle, thereby reducing NOx.

In the burner according to one aspect of the present invention, the ammonia gas ejection hole is formed in a direction such that the ammonia gas is inclined with respect to the central axis and ejected toward the outer peripheral side.

The ammonia gas is ejected from the ammonia gas ejection hole toward the outer circumferential side by tilting it with respect to the central axis, whereby the ammonia gas diffuses on the inner wall side of the outer cylinder nozzle and mixes with the fine powder fuel that has been concentrated by the concentrator toward the inner wall side of the outer cylinder nozzle. , which can promote combustion.

In the burner according to one aspect of the present invention, a distributor (82) is provided at the front end of the outer cylinder nozzle to separate the inner flow path and the outer flow path.

A distributor is provided at the front end of the outer cylinder nozzle to separate the inner flow path and the outer flow path of the outer cylinder nozzle, thereby forming an inner flow path in which primary air mainly flows and an outer flow path in which concentrated fine powder fuel mainly flows. Thereby, the primary air flowing in the inner flow path can be used for the combustion of ammonia gas, and the ignition of the fine powder fuel can be promoted by the concentrated fine powder fuel flowing in the outer flow path.

In one aspect of the burner of the present invention, ammonia gas is used as the ammonia fuel, the concentrator is provided on the outer wall of the inner cylinder nozzle, and is provided at a predetermined interval in the circumferential direction on the inner wall of the front end of the outer cylinder nozzle. There are a plurality of circumferential concentrators (85), and an ammonia gas ejection hole (85a) for ejecting the ammonia gas is formed in the circumferential concentrator.

The concentrator is provided on the outer wall of the inner cylinder nozzle, thereby concentrating the fine powder fuel toward the inner wall side of the outer cylinder nozzle. Then, a plurality of circumferential concentrators are installed at predetermined intervals in the circumferential direction on the inner wall in front of the outer cylinder nozzle, thereby partially reducing the width of the flow path in the circumferential direction and concentrating the fine fuel in the circumferential direction. Then, the ammonia gas is sprayed from the ammonia gas injection hole provided in the circumferential direction concentrator, thereby mixing with the fine powder fuel concentrated in the circumferential direction, thereby promoting combustion.

In one aspect of the burner of the present invention, liquid ammonia is used as the ammonia fuel, air is supplied to the inner cylinder nozzle, and an ammonia flame retainer (67) is provided at the front end of the inner cylinder nozzle for To maintain the flame of the ammonia supplied from the inner cylinder nozzle, a liquid ammonia supply pipe (90) is provided inside the inner cylinder nozzle and injects the liquid ammonia on the upstream side of the ammonia flame retainer.

Liquid ammonia is sprayed on the upstream side of the ammonia flame retainer provided at the front end of the inner cylinder nozzle. In this way, the air supplied to the inner cylinder nozzle is mixed with the air supplied to the inner cylinder nozzle on the upstream side of the ammonia flame retainer, and the liquid ammonia is vaporized as much as possible in the flame retainer. The flame retaining effect of the ammonia flame retainer is more stable. Thereby, the mixed combustion rate of the ammonia fuel can be increased.

In the burner according to one aspect of the present invention, liquid ammonia fuel is supplied from the inner cylinder nozzle, and ammonia is injected from an ammonia supply pipe provided on the outer peripheral side of the outer cylinder nozzle.

Liquid ammonia is supplied from the inner cylinder nozzle, and ammonia is injected from an ammonia supply pipe provided on the outer peripheral side of the outer cylinder nozzle, thereby increasing the mixed combustion rate of ammonia. Furthermore, liquid ammonia is supplied from the inner cylinder nozzle to lower the temperature near the outlet of the burner with the heat of vaporization, which may make it difficult to ignite. However, the amount of ammonia supplied from the ammonia supply pipe is reduced from the inner cylinder. The amount of liquid ammonia supplied by the nozzle whereby ignition can be properly carried out. In addition, the ammonia supplied from the ammonia supply pipe may be liquid or gas.

A boiler (10) according to one aspect of the present invention is provided with any one of the burners described above.

An operating method of a burner according to one aspect of the present invention. The burner is provided with: an inner cylinder nozzle extending along a central axis; and an outer cylinder nozzle extending along the central axis and disposed to cover the inner cylinder nozzle, The fine powder fuel and primary air are supplied into the furnace; the fine powder fuel flame retainer is used to maintain the flame of the aforementioned fine powder fuel supplied from the aforementioned outer cylinder nozzle; and the concentrator is provided inside the aforementioned outer cylinder nozzle to The aforementioned fine powder fuel is concentrated toward the side of the aforementioned fine powder fuel inflammator, and the operation method is to supply ammonia fuel to the aforementioned inner cylinder nozzle or the aforementioned outer cylinder nozzle.

In addition, according to the burner according to one aspect of the present invention, the following advantageous effects can be obtained. In a mixed combustion burner that simultaneously combusts fine powder fuel and ammonia fuel in a single burner, strict conditions are imposed on the ignitability and flame retention properties of the fuel, especially in a load area lower than the rated output. Therefore, the range of the upper limit and the lower limit of the mixed combustion rate tends to be narrowed.

In addition, in order to stably form and maintain the flames of multiple fuels with different combustion characteristics in the mixed combustion burner, the lower limit of the minimum load is likely to be higher than in a dedicated combustion burner for a specific fuel.

Wall-burning boilers that have multiple sections and rows of burners arranged on the wall of the furnace for combustion. Most of the burners in one section are used as a group for ignition, fire extinguishing, and output (load) adjustment. Applications such as stopping one burner section to prepare, adjusting the load of other operating burner sections, or further increasing the number of stopped burner sections to reduce the load are also performed.

If a wall combustion boiler is equipped with the burner of the present invention in each stage or row, the mixed combustion rate of the ammonia fuel can be improved. Even in areas where the boiler load is low, the upper and lower limits of the mixed combustion rate are wider, and the lower limit of the minimum load of the boiler is also lower. As a result, the boiler plant's operability and flexibility in response to mixed combustion rate and load changes will be improved.

The burner according to the present invention can increase the mixed combustion rate of ammonia fuel, that is, the upper limit of the mixed combustion rate is higher. Therefore, the existing burner is only a part of the boiler equipped with a burner for burning fine powder fuel. When converting to a mixed combustion boiler instead of a burner that can burn ammonia, it has the advantage that it only needs to replace a smaller number of burners compared to a burner with a lower upper limit of the mixed combustion rate. .

According to the burner of the present invention, the upper and lower limits of the mixed combustion rate of ammonia fuel are in a wide range. Therefore, there are burners that can exclusively combust specific fuel types and burners that can mix and combust ammonia and fine powder fuel. In a boiler plant, the burner selection or load adjustment range from use to stop has an advantage over a burner with a narrow range of the upper and lower limits of the mixed combustion rate of ammonia fuel.

Furthermore, stable combustion can be achieved even at low loads, and the lower limit of the minimum load can be set low.

The fuel supply ratio, that is, the mixed combustion rate, can be increased or decreased according to the conditions of the boiler plant's fuel dispatching, etc., making it easy to cope with flexible use.

10: Boiler 11:Stove 12: Combustion gas passage 13: flue 20: Combustion device 21:Burner 22: Powder fuel supply pipe 23: Bellows (wind regulator) 24: Air duct (air channel) 25:Extra air vent 26:Extra air channel 31:Grinder (Grinder) 32: Blowing fan (FDF) 41:Gas channel 42:Air preheater 43:Denitrification device 44:Dust collection device 45:Induction fan (IDF) 46:Desulfurization device 47:Chimney 50: Ammonia supply source 61: Inner barrel nozzle 62:Outer barrel nozzle 62a:Inner flow path 62b:Outside flow path 63:Oil nozzle 67: Ammonia inflammator 68:Restriction Department 68a: Upstream side inclined part 68b: Downstream side inclined part 69:Concentrator 69a: Upstream side inclined part 69b: Downstream side inclined part 69c: Cylindrical part 71: Inflammator for micron fuel 73:Secondary air flow path 74: Tertiary air flow path 74a: Spinner 80,80’: Gap (ammonia gas ejection hole) 82:Distributor 85: Circumferential concentrator 85a: Ammonia gas ejection hole 85b:Installation Department 85c: upstream end 85d: middle position 85e: Downstream end 85f: Downstream side 85g: Bottom 87: Ammonia gas supply pipe 90: Liquid ammonia supply pipe 92: Liquid ammonia spray nozzle 92a: Injection hole 95:Liquid ammonia supply pipe 101: stove wall 102:Superheater 103:Reheater 104: Economizer

[Fig. 1] A schematic structural diagram showing a boiler according to the first embodiment of the present invention. [Fig. 2] shows a longitudinal sectional view of the burner of Fig. 1. [Fig. 3A] A longitudinal sectional view showing the burner according to the second embodiment of the present invention. [Fig. 3B] A front view showing the inner cylinder nozzle and the outer cylinder nozzle in Fig. 3A. [Fig. 4A] A longitudinal sectional view showing a burner according to a modified example of Fig. 3A. [Fig. 4B] A front view showing the inner cylinder nozzle and the outer cylinder nozzle in Fig. 4A. [Fig. 5] A longitudinal sectional view showing a burner according to a third embodiment of the present invention. [Fig. 6A] A longitudinal sectional view showing the burner according to the fourth embodiment of the present invention. [Fig. 6B] A front view showing the inner cylinder nozzle and the outer cylinder nozzle in Fig. 6A. [Fig. 6C] A perspective view showing the circumferential concentrator of Figs. 6A and 6B. [Fig. 7A] A longitudinal sectional view showing the burner according to the fifth embodiment of the present invention. [Fig. 7B] shows a longitudinal sectional view of the liquid ammonia injection nozzle. [Fig. 8] A longitudinal sectional view showing a burner according to a sixth embodiment of the present invention.

11:Stove

21:Burner

61: Inner barrel nozzle

62:Outer barrel nozzle

63:Oil nozzle

67: Ammonia inflammator

68:Restriction Department

68a: Upstream side inclined part

68b: Downstream side inclined part

69:Concentrator

69a: Upstream side inclined part

69b: Downstream side inclined portion

69c: Cylindrical part

71: Inflammator for micron fuel

73:Secondary air flow path

74: Tertiary air flow path

74a: Spinner

101: stove wall

CL: central axis

Claims (12)

A burner having: an inner barrel nozzle extending along the central axis; An outer cylinder nozzle, which extends along the aforementioned central axis and is arranged to cover the aforementioned inner cylinder nozzle, supplies fine powder fuel and primary air into the furnace; A flame retainer for fine powder fuel, which maintains the flame of the aforementioned fine powder fuel supplied from the aforementioned outer cylinder nozzle; and a concentrator, which is installed inside the outer cylinder nozzle and concentrates the fine powder fuel toward the side of the flame retainer for fine powder fuel, Ammonia fuel is supplied to the inner cylinder nozzle or the outer cylinder nozzle. The burner as claimed in claim 1, wherein, Using ammonia gas as the aforementioned ammonia fuel, Ammonia gas and air are supplied to the aforementioned inner cylinder nozzle, An ammonia flame retainer is provided at the front end of the inner cylinder nozzle for maintaining the flame of the ammonia gas supplied from the inner cylinder nozzle. The burner as described in claim 2 has: A control valve that controls the air flow supplied to the inner cylinder nozzle, a control unit that controls the aforementioned control valve, The control unit controls the control valve to reduce the flow rate of the air in response to an increase in the mixed combustion rate of the ammonia fuel. The burner as claimed in claim 1, wherein, Using ammonia gas as the aforementioned ammonia fuel, Ammonia gas is supplied to the aforementioned inner cylinder nozzle, The aforementioned concentrator is located on the outer wall of the aforementioned inner cylinder nozzle, The concentrator is provided with an ammonia gas ejection hole for ejecting the ammonia gas introduced from the inner cylinder nozzle into the outer cylinder nozzle. The burner according to claim 4, wherein the ammonia gas ejection hole is formed in a direction such that the ammonia gas is ejected along the central axis. The burner according to claim 4, wherein the ammonia gas ejection hole is formed in a direction such that the ammonia gas is inclined with respect to the central axis and ejected toward the outer peripheral side. The burner according to claim 4, wherein a distributor is provided at the front end of the outer cylinder nozzle to separate the inner flow path and the outer flow path. The burner as claimed in claim 1, wherein, Using ammonia gas as the aforementioned ammonia fuel, The aforementioned concentrator is located on the outer wall of the aforementioned inner cylinder nozzle, A plurality of circumferential concentrators are provided at predetermined intervals in the circumferential direction on the inner wall in front of the outer cylinder nozzle. The circumferential concentrator is provided with an ammonia gas ejection hole for ejecting the ammonia gas. The burner as claimed in claim 1, wherein, Using liquid ammonia as the aforementioned ammonia fuel, Air is supplied to the aforementioned inner cylinder nozzle, An ammonia flame retainer is provided at the front end of the inner cylinder nozzle, which is used to maintain the flame of the ammonia supplied from the inner cylinder nozzle. A liquid ammonia supply pipe is provided inside the inner cylinder nozzle for injecting the liquid ammonia on the upstream side of the ammonia inflammator. The burner as claimed in claim 1, wherein, Liquid ammonia fuel is supplied from the aforementioned inner cylinder nozzle, Ammonia is injected from an ammonia supply pipe provided on the outer peripheral side of the outer cylinder nozzle. A boiler equipped with a burner according to any one of requirements 1 to 10. An operation method of a burner. The aforementioned burner has: an inner barrel nozzle extending along the central axis; An outer cylinder nozzle, which extends along the aforementioned central axis and is arranged to cover the aforementioned inner cylinder nozzle, supplies fine powder fuel and primary air into the furnace; A flame retainer for fine powder fuel, which maintains the flame of the aforementioned fine powder fuel supplied from the aforementioned outer cylinder nozzle; and a concentrator, which is installed inside the outer cylinder nozzle and concentrates the fine powder fuel toward the side of the flame retainer for fine powder fuel, The operation method of the aforementioned burner, Ammonia fuel is supplied to the inner cylinder nozzle or the outer cylinder nozzle.

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