阅读说明：本技术 循环流化床锅炉 (Circulating fluidized bed boiler ) 是由 蒋俊芳 于 2021-08-02 设计创作，主要内容包括：本发明的实施例提供了一种循环流化床锅炉,涉及循环流化床锅炉燃烧部件领域。旨在提高锅炉的燃烧效率。循环流化床锅炉包括炉体以及二次风喷嘴；二次风喷嘴为锥形管,二次风喷嘴具有位置相对的大端以及小端,二次风喷嘴设置在炉体上,且二次风喷嘴的小端伸入炉体内；二次风喷嘴包括设置在炉体的角落处的第一喷嘴；第一喷嘴的中心线与炉体的炉膛中心线呈夹角设置。二次风喷嘴采用锥形结构,能够增加二次风的动能；第一喷嘴朝向炉膛中心线倾斜设置,能够防止二次风对侧墙水冷壁管的磨损,同时能够最大程度地减少二次风对贴壁下降流的影响,保证物料混合效果,提高锅炉热效率,从而降低飞灰含碳量,降低锅炉的热损失,降低使用成本。(The embodiment of the invention provides a circulating fluidized bed boiler, and relates to the field of combustion parts of circulating fluidized bed boilers. Aiming at improving the combustion efficiency of the boiler. The circulating fluidized bed boiler comprises a boiler body and a secondary air nozzle; the secondary air nozzle is a conical tube and is provided with a large end and a small end which are opposite in position, the secondary air nozzle is arranged on the furnace body, and the small end of the secondary air nozzle extends into the furnace body; the secondary air nozzle comprises a first nozzle arranged at the corner of the furnace body; the central line of the first nozzle and the central line of the furnace chamber of the furnace body form an included angle. The secondary air nozzle adopts a conical structure, so that the kinetic energy of secondary air can be increased; first nozzle sets up towards furnace central line slope, can prevent the wearing and tearing of overgrate air to side wall water wall pipe, can reduce the influence of overgrate air to adherence downflow simultaneously furthest, guarantees the material mixing effect, improves boiler thermal efficiency to reduce fly ash carbon content, reduce the heat loss of boiler, reduce use cost.)

1. A circulating fluidized bed boiler, comprising:

a furnace body (700) and a secondary air nozzle (500);

the secondary air nozzle (500) is a conical tube, the secondary air nozzle (500) is provided with a large end and a small end which are opposite in position, the secondary air nozzle (500) is arranged on the furnace body (700), and the small end of the secondary air nozzle (500) extends into the furnace body (700);

the secondary air nozzle (500) comprises a first nozzle (501) arranged at the corner of the furnace body (700); the central line of the first nozzle (501) and the central line of the hearth of the furnace body (700) form an included angle.

2. The circulating fluidized bed boiler of claim 1, wherein:

the secondary air nozzles (500) are arranged in a single layer.

3. The circulating fluidized bed boiler of claim 1, wherein:

the furnace body (700) comprises a front wall (710);

the circulating fluidized bed boiler also comprises an air box (100) arranged on the front wall (710) and a plurality of secondary air pipes (200); one ends of the secondary air pipes (200) are communicated with the air box (100), and the other ends of the secondary air pipes (200) are respectively communicated with the secondary air nozzles (500);

the cross-sectional area of the windbox (100) on the front wall (710) is 2.1-2.3 times the sum of the cross-sectional areas of the secondary air ducts (200) on the front wall (710).

4. The circulating fluidized bed boiler of claim 3, wherein:

the air speed range in the air box (100) is 15-20m/s, and the air speed in the secondary air pipe (200) is 20-25 m/s.

5. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

the secondary air nozzle (500) further comprises a second nozzle (502) arranged between two adjacent corners of the furnace body (700); the diameter of the small end of the second nozzle (502) is larger than the diameter of the small end of the first nozzle (501).

6. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

the length range of the secondary air nozzle (500) is 640-660 mm.

7. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

the circulating fluidized bed boiler also comprises an air distribution plate; the size range of the secondary air nozzle (500) to the wind distribution plate is 3450-.

8. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

the included angle between the central line of the first nozzle (501) and the central line of the hearth of the furnace body (700) ranges from 10 degrees to 20 degrees.

9. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

when the volatile component Vdaf in the fuel is 20-30%, the proportion of the secondary air volume in the total air volume of the primary air and the secondary air is 50%, and when the volatile component Vdaf in the fuel is 31-40%, the proportion of the secondary air volume in the total air volume of the primary air and the secondary air is 55-60%.

10. The circulating fluidized bed boiler according to any one of claims 1 to 4, wherein:

the circulating fluidized bed boiler further comprises a swirler (510); the spinning disk (510) is arranged on the inner wall of the secondary air nozzle (500), and the spinning disk (510) is spirally arranged around the axial lead of the secondary air nozzle (500); the cyclone plates (510) are used for enabling the wind in the secondary wind nozzle (500) to gradually converge along the direction from the large end to the small end.

Technical Field

The invention relates to the field of combustion parts of circulating fluidized bed boilers, in particular to a circulating fluidized bed boiler.

Background

In order to respond to the national call for energy conservation and emission reduction, many power plants adopt circulating fluidized bed boilers of low-nitrogen combustion technology; the material concentration in the circulating fluidized bed boiler of the low-nitrogen combustion technology is relatively high, and the requirement of controlling NOx emission can be met. After the concentration of the materials in the hearth rises, the back pressure in the hearth is relatively high, so that secondary air is influenced to be effectively blown into the center of the hearth for oxygen supplementation, the fly ash is brought out of the hearth under the condition of incomplete combustion, and the heat loss of the circulating fluidized bed boiler is caused. In the bottom slag and fly ash after the combustion of the circulating fluidized bed boiler, the proportion of fly ash is about seven, and the excessively high carbon content of fly ash increases the fuel consumption for a power plant. Therefore, the carbon content of the fly ash is reduced, the operation cost is reduced, and the economic benefit and the social benefit are improved, which is of great importance.

Disclosure of Invention

Objects of the present invention include, for example, providing a circulating fluidized bed boiler capable of improving combustion efficiency of the boiler.

Embodiments of the invention may be implemented as follows:

an embodiment of the present invention provides a circulating fluidized bed boiler, including:

a furnace body and a secondary air nozzle;

the secondary air nozzle is a conical tube and is provided with a large end and a small end which are opposite in position, the secondary air nozzle is arranged on the furnace body, and the small end of the secondary air nozzle extends into the furnace body;

the secondary air nozzle comprises a first nozzle arranged at the corner of the furnace body; the central line of the first nozzle and the central line of the furnace chamber of the furnace body form an included angle.

Optionally, the secondary air nozzles are arranged in a single layer.

Optionally, the furnace body comprises a front wall;

the circulating fluidized bed boiler also comprises an air box and a plurality of secondary air pipes, wherein the air box is arranged on the front wall; one ends of the secondary air pipes are communicated with the air box, and the other ends of the secondary air pipes are respectively communicated with the secondary air nozzles;

the cross section area of the air bellow on the front wall is 2.1-2.3 times of the sum of the cross section areas of the plurality of secondary air pipes on the front wall.

Optionally, the air velocity in the windbox ranges from 15 to 20m/s and the air velocity in the secondary air duct ranges from 20 to 25 m/s.

Optionally, the secondary air nozzle further comprises a second nozzle arranged between two adjacent corners of the furnace body; the diameter of the small end of the second nozzle is larger than the diameter of the small end of the first nozzle.

Optionally, the length range of the secondary air nozzle is 640-660 mm.

Optionally, the circulating fluidized bed boiler further comprises an air distribution plate; the size range of the secondary air nozzle to the air distribution plate is 3450-3950 mm.

Optionally, an included angle between a center line of the first nozzle and a furnace center line of the furnace body ranges from 10 degrees to 20 degrees.

Optionally, when the volatile component Vdaf in the fuel is 20% to 30%, the proportion of the secondary air volume to the total air volume of the primary air and the secondary air volume is 50%, and when the volatile component Vdaf in the fuel is 31% to 40%, the proportion of the secondary air volume to the total air volume of the primary air and the secondary air volume is 55% to 60%.

Optionally, the circulating fluidized bed boiler further comprises a swirl plate; the spinning disk is arranged on the inner wall of the secondary air nozzle and is spirally arranged around the axial lead of the secondary air nozzle; the cyclone sheet is used for enabling the wind in the secondary air nozzle to gradually collect along the direction from the large end to the small end.

The circulating fluidized bed boiler of the embodiment of the present invention has advantageous effects including, for example:

the circulating fluidized bed boiler comprises a boiler body and a secondary air nozzle; the secondary air nozzle is a conical tube and is provided with a large end and a small end which are opposite in position, the secondary air nozzle is arranged on the furnace body, and the small end of the secondary air nozzle extends into the furnace body; the secondary air nozzle comprises a first nozzle arranged at the corner of the furnace body; the central line of the first nozzle and the central line of the furnace chamber of the furnace body form an included angle. The overgrate air nozzle adopts the toper structure, can increase the kinetic energy of overgrate air, first nozzle sets up towards furnace central line slope, can prevent the wearing and tearing of overgrate air to side wall water-cooled wall pipe, simultaneously can reduce the influence of overgrate air to the adherence downflow, guarantee the material and mix the effect, make overgrate air and the mixture of stove inner loop material more abundant, improve boiler thermal efficiency, reduce the interior CO value of stove and flying dust carbon content, still can effectively improve the utilization ratio of boiler under the condition of low bed temperature, overcome the higher problem of flying dust carbon content under the low bed temperature, use cost is reduced, economic benefits and social are improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic structural view from a front perspective of a circulating fluidized bed boiler according to an embodiment of the present invention;

FIG. 2 is a schematic top view of a circulating fluidized bed boiler according to an embodiment of the present invention;

FIG. 3 is a schematic structural view of a front wall of a circulating fluidized bed boiler according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of a rear wall of a circulating fluidized bed boiler according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a first view angle of a secondary air duct according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a second viewing angle of the secondary air duct according to the embodiment of the present invention;

fig. 7 is a schematic structural diagram of a third viewing angle of the secondary air duct according to the embodiment of the present invention.

Icon: 10-circulating fluidized bed boiler; 100-bellows; 200-secondary air pipe; 300-an expansion joint; 400-air damper; 500-secondary air nozzle; 510-a spinning disk; 501-a first nozzle; 502-a second nozzle; 600-sealing the housing; 700-furnace body; 710-front wall; 720-back wall.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Because the concentration of the circulating material in the boiler is high, and the secondary air nozzle has large back pressure, the secondary air can not completely penetrate through the center of the hearth to be mixed with the circulating material with oxygen deficiency in the middle, so that the fly ash is brought out of the hearth under the condition of incomplete combustion, and the heat loss of the circulating fluidized bed boiler is caused.

The circulating fluidized bed boiler 10 provided in the present embodiment will be described in detail with reference to fig. 1 to 7.

Referring to fig. 1 and 2, an embodiment of the present invention provides a circulating fluidized bed boiler 10, including a furnace body 700 and a secondary air nozzle 500; the secondary air nozzle 500 is a conical tube, the secondary air nozzle 500 is provided with a large end and a small end which are opposite, the secondary air nozzle 500 is arranged on the furnace body 700, and the small end of the secondary air nozzle 500 extends into the furnace body 700; the secondary air nozzle 500 includes a first nozzle 501 provided at a corner of the furnace body 700; the center line of the first nozzle 501 forms an included angle with the center line of the furnace body 700.

The size of the boilers varies, and the size arrangement of the overfire air nozzles 500 varies. The embodiment of the invention is explained by taking the installation of a boiler of 75t/h-280t/h as an example.

Referring to fig. 1, the circulating fluidized bed boiler 10 further includes a wind box 100, a secondary wind pipe 200, an expansion joint 300, a damper 400, and a sealing cover 600 provided on a furnace body 700. The air box 100, the secondary air pipe 200, the expansion joint 300 and the secondary air nozzle 500 are sequentially connected, the small end of the secondary air nozzle 500 extends into the furnace body 700 through the sealing cover 600, and the air damper 400 is arranged on the secondary air pipe 200. The air supply to the furnace body 700 is realized. Wherein, the big end of the secondary air nozzle 500 is communicated with the wind box 100, and the small end of the secondary air nozzle 500 extends into the furnace body 700. It should be noted that: the large end of the secondary air nozzle 500 refers to the end of the secondary air nozzle 500 with a larger diameter, and the small end of the secondary air nozzle 500 refers to the end of the secondary air nozzle 500 with a smaller diameter; specifically, the diameter of the large end of the secondary air nozzle 500 is greater than the diameter of the small end of the secondary air nozzle 500.

In this embodiment, the air box 100, the secondary air duct 200, and the secondary air nozzle 500 are connected in sequence; the air speed range in the wind box 100 is 15-20m/s, and the air speed in the secondary air pipe 200 is 20-25 m/s. To the secondary air nozzle 500, the air velocity is highest.

In this embodiment, the secondary air nozzle 500 is a tapered tube, which can reduce the on-way resistance, so that the secondary air has greater kinetic energy.

Referring to fig. 2, the furnace body 700 includes four corners, each of which is provided with the first nozzle 501. Referring to fig. 1, the furnace centerline is the line designated by reference character a. Referring to FIG. 2, the furnace centerline is the point designated by reference numeral B.

As the middle part of the hearth is in ascending flow and the periphery of the hearth is in descending flow. The height from the secondary air nozzle (namely the small end of the secondary air nozzle 500) to the smoke window at the outlet of the hearth is higher, and the secondary air has enough time to perform mixed combustion with the circulating materials in the furnace. The secondary air that is located the corner department is because being close the position of downcast, and the secondary air only has shorter distance to the side wall, and too big secondary air can destroy the flow direction of downcast, easily causes the wearing and tearing of offside wall water wall pipe, need often carry out the abrasionproof or change to the water wall pipe. Consequently, every first nozzle 501 sets up towards furnace central line slope, can prevent the wearing and tearing of overgrate air to side wall water wall pipe, can reduce the influence of overgrate air to adherence downflow simultaneously to the at utmost, guarantees the material and mixes the effect.

With continued reference to FIG. 2, in this embodiment, the centerline of the first nozzle 501 is coplanar with the furnace centerline of the furnace body 700. That is, the first nozzle 501 is inclined toward the center of the furnace body 700. Because the secondary air deviates to the center during arrangement, the sprayed position of the secondary air is sprayed into the upward flow of the middle part, the time for mixing the secondary air and the circulating materials in the furnace is prolonged, and the secondary air is more fully utilized. Not only can satisfy the oxygen demand in the middle of the furnace, but also can prevent the excessive secondary air quantity on the edge from wearing and tearing the side wall water wall pipe.

In this embodiment, the included angle between the center line of the first nozzle 501 and the center line of the furnace 700 is 10-20 °.

Wherein, the included angle between the central line of the first nozzle 501 and the central line of the hearth of the furnace body 700 is related to the length of the first nozzle 501 extending into the furnace body 700, and if the length is short, the included angle is large; the included angle is small if the length is long.

In this embodiment, the overfire air nozzles 500 are arranged in a single layer. The secondary air preheater has the advantages that the on-way resistance between the secondary air preheater and the secondary air nozzle is favorably reduced, the effective utilization rate of the secondary air fan is improved, and the power consumption of the fan is reduced. The secondary air is changed into single-layer arrangement from the original double-layer arrangement, the original lower-layer secondary air is cancelled, and only one upper-layer secondary air is arranged. The blowing-in point of the secondary air on the upper layer is selected according to the size of the furnace, the height is 3000-4000 mm below 200t/h, and 4000-5000 mm at 200-400 t/h. The selected position is selected according to the backpressure in the hearth, and the arrangement is carried out at the position with reasonable backpressure, so that enough blowing-in depth and speed are ensured after secondary air enters the hearth.

In addition, the periphery of the hearth of the circulating fluidized bed boiler is not anoxic, and the middle part of the hearth is anoxic; in this embodiment, according to the distribution rule of oxygen in the furnace chamber of the circulating fluidized bed boiler, different secondary air arrangements are required to be performed in the furnace for oxygen supplementation in different regions. The secondary air nozzle in the middle of the hearth has a large diameter so as to provide large air volume; and the secondary air nozzle at the corner adopts a small diameter and only provides a small air volume.

Specifically, the secondary air nozzle 500 further includes a second nozzle 502 disposed between two adjacent corners of the furnace body 700; the diameter of the small end of the second nozzle 502 is larger than the diameter of the small end of the first nozzle 501.

That is, the small ends of the secondary air nozzles 500 are arranged in unequal diameters, and distributed air distribution is performed in the furnace according to the requirements of different areas in the furnace.

For example, the small end of the second nozzle 502 has a diameter of 220 mm. The small end of the first nozzle 501 has a diameter of 200 mm. The diameter of the large end of the second nozzle 502 and the diameter of the large end of the first nozzle 501 are both 377 mm.

Referring to fig. 5, in the present embodiment, the inclination angle from the large end of the first nozzle 501 to the small end of the first nozzle 501 ranges from 6 ° to 7 °; the angle of inclination from the large end of the second nozzle 502 to the small end of the second nozzle 502 ranges from 6 to 7. The inclination angle from the large end of the first nozzle 501 to the small end of the first nozzle 501 is an acute angle between a generatrix of the conical surface of the first nozzle 501 and a center line, that is, an angle denoted by reference numeral W in fig. 5. Similarly, the inclination angle from the large end of the second nozzle 502 to the small end of the second nozzle 502 is also an acute angle between the generatrix and the centerline of the conical surface of the second nozzle 502. For example, the angle of inclination from the large end of the first nozzle 501 to the small end of the first nozzle 501 is 7 °. The angle of inclination from the large end of the second nozzle 502 to the small end of the second nozzle 502 is 6 °. The angle of inclination of the large end of the first nozzle 501 to the small end of the first nozzle 501 is greater than the angle of inclination of the large end of the second nozzle 502 to the small end of the second nozzle 502.

The secondary air nozzle 500 adopts a conical pipe, which is beneficial to reducing the on-way resistance, so that the secondary air has larger kinetic energy. The inclination angles of the first nozzle 501 and the second nozzle 502 are 6-7 degrees, the resistance of the secondary air nozzle 500 is reduced by controlling the angle difference, and the resistance is only controlled at the tail end position of the fire side of the hearth, so that the secondary air nozzle has stronger kinetic energy, and the adjusted large end and small end are ensured to have the flow velocity of more than or equal to 90m/s in a hot air state. The secondary air nozzle 500 has a larger nozzle opening, larger secondary air volume and more uniform mixing.

In this embodiment, the length of the secondary air nozzle 500 is 640-660 mm. Specifically, the length of the secondary air nozzle 500 is 650 mm. The length is designed to be longer, so that the secondary air is ensured to have higher acceleration in the cone, and then the speed at the nozzle is set according to the size of the depth direction dimension of the hearth. For example, the speed of the nozzle is designed to reach 75-100 m/s according to the depth direction size of the hearth, and the kinetic energy is very high.

Referring again to fig. 2, in conjunction with fig. 3 and 4, in the present embodiment, the furnace body 700 includes a front wall 710; the circulating fluidized bed boiler further comprises a wind box 100 arranged on the front wall 710 and a plurality of secondary wind pipes 200; one ends of the plurality of secondary air pipes 200 are all communicated with the air box 100, and the other ends of the plurality of secondary air pipes 200 are respectively communicated with the secondary air nozzles 500; the cross-sectional area of the windbox 100 of the front wall 710 is 2.1 times to 2.3 times the sum of the cross-sectional areas of the plurality of secondary ducts 200 of the front wall 710.

Referring to fig. 3 and 4, the furnace body 700 includes a front wall 710 and a rear wall 720, and a plurality of secondary air ducts 200 and a plurality of secondary air nozzles 500 are respectively disposed on the front wall 710 and the rear wall 720. The cross-sectional area of the windbox 100 provided on the front wall 710 is equal to 2.1 times to 2.3 times the sum of the cross-sectional areas of the plurality of secondary ducts 200 provided on the front wall 710. Similarly, the cross-sectional area of the bellows 100 provided on the rear wall 720 is equal to 2.1 times to 2.3 times the sum of the cross-sectional areas of the secondary air ducts 200 provided on the rear wall 720.

Specifically, the cross-sectional area of the windbox 100 on the front wall 710 is equal to 2.2 times the sum of the cross-sectional areas of the plurality of secondary air ducts 200 on the front wall 710.

After the secondary air comes out from the air preheater, the secondary air is conveyed to the secondary air nozzle 500 by the large air box 100, the on-way resistance between the secondary air preheater and the secondary air nozzle 500 can be reduced by the large-cross-sectional-area air box 100, the effective utilization rate of the secondary air fan is improved, and the power consumption of the fan is reduced. Wherein, the air preheater is the air preheater. The air pre-heater is used for conducting heat carried in flue gas exhausted from a flue at the tail part of a boiler to air before entering the boiler through a radiating pipe so as to preheat the air to a certain temperature. The device is used for improving the heat exchange performance of the boiler and reducing energy consumption.

In this embodiment, the circulating fluidized bed boiler further includes an air distribution plate; the size range of the secondary air nozzle 500 to the air distribution plate is 3450-3950 mm. The distance between the height of the secondary air nozzle of the early circulating fluidized bed boiler and the air distribution plate is in the range of 2500-; the invention provides that the size range of the distance between the center of the nozzle and the wind distribution plate is designed as follows: 3450 and 3950 mm.

In this embodiment, the proportion of the secondary air volume to the total air volume is 50% to 60%. In the embodiment, the proportion of the primary air and the secondary air is optimized, the proportion of the primary air is reduced, and the reducing atmosphere of the bottom area is ensured. The proportion of primary air and secondary air of the early circulating fluidized bed boiler is 60% to 40% no matter what fuel. In the embodiment, the proportion of the primary air and the secondary air is set according to the size of volatile matters in the fuel; when the volatile component Vdaf in the fuel is 20-30%, the proportion of the secondary air volume in the total air volume of the primary air and the secondary air is 50%, and when the volatile component Vdaf in the fuel is 31-40%, the proportion of the secondary air volume in the total air volume of the primary air and the secondary air is 55-60%. By adopting the design, the generation of NOx and the power consumption of the primary fan can be effectively reduced.

Referring to fig. 6 and 7, in this embodiment, the swirl plates 510 are disposed inside the secondary air nozzle 500, and the hot air in the secondary air nozzle 500 is in a rotating state after entering the furnace chamber, so that the peripheral anoxic materials can be sucked into the vortex formed by the secondary air in the rotating process, and the disturbance and mixing of the circulating materials in the furnace are more uniform; because the shape that the rotatory in-process of overgrate air formed is similar to the drill bit, it is darker to insufflate the degree of depth, and mixes more evenly, makes wind-force have bigger kinetic energy for overgrate air and stove inner circulation material mix more fully, improves the disturbance to stove inner circulation material. Therefore, set up the conical tube of spinning disk 510, can make the overgrate air gather more, can blow in the overgrate air effectively to furnace center and carry out the oxygenating, further improve the disturbance to the interior circulation material of stove, improve combustion efficiency to reduce flying dust carbon content.

Referring to fig. 6 and 7, in the present embodiment, the number of the swirl plates 510 is plural; the plurality of spinning disks 510 are arranged at intervals along the circumferential direction of the secondary air nozzle 500, and each spinning disk 510 is spirally arranged around the axial lead of the secondary air nozzle 500.

Specifically, in this embodiment, the number of the swirl plates 510 is three, and the three swirl plates 510 are uniformly distributed along the circumferential direction of the secondary air nozzle 500. Helping to improve the pooling effect of the swirl plates 510.

In this embodiment, the helix angle of the swirl plate 510 is in the range of 16-20. Specifically, the helix angle of the swirl plate 510 is 18 °. The spinning disks 510 can be guaranteed to have a better collecting effect on the wind. The width of the spinning disk 510 is 30 mm.

It should be noted that: the term "helix angle" refers to the acute angle between the tangent of a cylindrical helix and the straight generatrix of the cylindrical surface passing through the tangent point on the cylindrical surface, and is called helix angle. In this embodiment, the acute angle is defined between the tangent of the spinning disk 510 and the straight generatrix of the conical surface passing through the tangent point.

It should be noted that: the first nozzle 501 is identical to the second nozzle 502 except for the differences noted herein. For example, the first nozzle 501 and the second nozzle 502 are tapered tubes, and each has a swirl plate 510 disposed therein.

The present embodiment provides a circulating fluidized bed boiler 10 having at least the following advantages:

the secondary air nozzle 500 adopts a conical pipe, so that the on-way resistance can be reduced, and the secondary air has larger kinetic energy. The combustion efficiency of the boiler is improved.

First nozzle 501 sets up towards furnace central line slope, can prevent the wearing and tearing of overgrate air to side wall water wall pipe, can reduce the influence of overgrate air to adherence downflow simultaneously furthest.

The small ends of the secondary air nozzles 500 are arranged in unequal diameters, and different secondary air arrangements are carried out in the furnace according to the oxygen supply requirements of different areas according to the distribution rule of the oxygen amount in the furnace. The diameter of the small end of the second nozzle 502 is set larger than that of the first nozzle 501. Further prevent the wearing and tearing of overgrate air spout offside wall water-cooled wall for the overgrate air can furthest's reduction to the influence of adherence downflow.

The inside of overgrate air nozzle 500 is provided with spinning disk 510, and hot-blast being in the rotating state after getting into furnace in the overgrate air nozzle 500, the shape that rotatory in-process formed is similar to the drill bit, and it is darker to blow in the degree of depth, has bigger kinetic energy, mixes more evenly.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.