CN212132414U - A fluidized bed boiler air cap - Google Patents

Abstract

The utility model discloses an air cap for a fluidized bed boiler, which comprises an air cap cover and an air inlet pipe. The air cap cover is provided with an inner cavity, and the upper end of the air inlet pipe extends into the inner cavity of the air cap cover. An annular air duct is formed between the upper end of the air duct and the inner wall of the hood cover, the upper end of the air inlet duct is provided with a number of air inlet holes that communicate with the annular air duct, and the lower part of the hood cover is provided with a number of air inlets For the air outlet communicated with the annular air duct, the axis line of the air outlet extends outward along the radial direction of the hood cover, and forms a downwardly inclined angle of 40-80° with the horizontal plane. The new fluidized bed boiler air cap, through the optimization of the air outlet angle, enhances the disturbance of the fluidized bed material, solves the problems of slag leakage and wear of the air cap, and ensures the safe operation of the boiler.

Description

A fluidized bed boiler air cap

technical field

The utility model relates to boiler equipment, in particular to a fluidized bed boiler air cap.

Background technique

The circulating fluidized bed boiler has the advantages of wide fuel adaptability, high desulfurization efficiency in the furnace, low nitrogen oxide emission, high combustion efficiency, large load regulation ratio and comprehensive utilization of ash and slag. It is widely used in power station boilers, industrial boilers and other fields Wide range of applications. Circulating fluidized bed (CFB) boilers are rapidly developing in the direction of large-scale, high-parameterization, and supercritical. With the continuous increase of boiler capacity, the uniformity of air distribution on the air distribution plate becomes more important. The key difference between the circulating fluidized bed boiler and other boilers is the fluidized combustion of bed material. The residence time of the bed material in the furnace is increased, and the heat exchange between the gas and solid phases is also strengthened. The air cap is the key to ensure the uniform fluidization of the bed material. The boiler air cap is responsible for evenly transporting the air into the furnace bed material layer to meet the air required for boiler combustion, and to control the amount of air supply, so that the furnace bed material layer is always Keep the fluidized boiling state to make the coal burn completely.

The hood is prone to wear in actual operation, which affects the safe, stable and economical operation of the unit. Therefore, it is of great practical application value to carry out research on the resistance characteristics of the hood and optimize the structure of the hood, thereby reducing the wear rate of the hood and prolonging its service life. When slag leakage occurs, a large amount of ash (bed material) will leak to the water-cooled air chamber and ignition air duct through the air cap. The accumulation of more and more will block the primary air duct, which is extremely harmful to the normal operation of the boiler and fluidization, and may even be damaged. Forced shutdown of the furnace; slag leakage will also cause serious wear to the water-cooled air chamber lining under the disturbance of the primary air, and the inner wall of the air cap will be worn by fine particles entering the air cap with the primary air. The bed material at the bottom of the furnace forms a vortex under the action of the jet at the outlet of the air cap, which causes wear to the nearby air cap. This problem is one of the most serious problems in the operation of the fluidized bed boiler. The study of the air cap is of great significance to the stable and clean operation of the fluidized bed boiler. Because the current fluidized bed boiler air cap has no built-in air inlet pipe, combustion pulsation is prone to occur when the boiler is operating at low load, and adjacent air caps are easily worn due to blowing against each other, resulting in slag leakage. Since the pulsation size of combustion is related to the bed height, fuel particle size, the size of the air cap pores, the size of the fluidized air volume, the bed structure, etc. It is difficult to avoid the problems of air cap wear and slag leakage.

Utility model content

In order to overcome the shortcomings of the boiler air cap mentioned in the above-mentioned prior art, the utility model provides a novel fluidized bed boiler air cap. By optimizing the angle of the air outlet, the disturbance of the fluidized bed material is enhanced and the air cap is solved. The wear and slag leakage problems ensure the safe operation of the boiler.

The utility model is realized as follows: an air cap for a fluidized bed boiler includes an air cap cover and an air inlet pipe, the air cap cover is provided with an inner cavity, and the upper end of the air inlet pipe extends into the inner cavity of the air cap cover , an annular air duct is formed between the upper end of the air inlet duct and the inner wall of the hood cover, the upper end of the air inlet duct is provided with a number of air inlet holes that communicate with the annular air duct, and the lower part of the hood cover A plurality of air outlets communicated with the annular air duct are provided, and the axis lines of the air outlets extend outward along the radial direction of the hood cover, and form a downwardly inclined angle of 40-80° with the horizontal plane.

Further, the number of the air outlets is 4 to 12, and the circumference of all the air outlets is evenly distributed on the side wall of the hood cover. Wherein, the number of the air outlets is preferably 8.

Further, the included angle between the axis line of the air outlet and the horizontal plane is 50-70°, preferably 60°.

Further, the inner diameter of the hood cover is φ30˜50 mm, preferably φ40 mm.

Further, the number of the air inlet holes is 4 to 12, preferably 6, and the air inlet holes are arranged at a distance of 5 to 10 mm from the top of the air inlet pipe, preferably 6 mm.

Further, a gap of 8-10 mm is formed between the top end of the air inlet pipe and the top end of the inner wall of the hood cover.

Further, the hood cover and the air inlet pipe are integrally formed, which is convenient for production and processing, and the overall structure is more stable.

The beneficial effects of the utility model are: the design of the design increases the angle between the longitudinal axis of the air outlet and the horizontal plane and the air inlet pipe is built in to form an annular air duct sealing structure, which avoids the phenomenon of opposite blowing between the hood holes and reduces the wear of the hood. It completely eliminates the problem of slag leakage that is easy to occur when the boiler is running at low load, and makes the bed material on the boiler air distribution plate fluidize evenly, which improves the combustion efficiency of the fluidized bed boiler and reduces energy consumption. safe operation.

Description of drawings

Fig. 1 is the structural front view of the utility model;

Fig. 2 is the sectional structure schematic diagram of A-A in Fig. 1;

FIG. 3 is a schematic cross-sectional structure diagram of B-B in FIG. 1 .

Detailed ways

In order to facilitate the understanding of the present invention, a more comprehensive description of the fluidized bed boiler air cap of the present solution will be given below with reference to the related drawings. Preferred embodiments of the solution of the present invention are given in the accompanying drawings of this embodiment. However, the solution of the present invention can be implemented in many different forms, and is not limited to the embodiments described herein. Rather, these examples are provided so that the disclosure of convection fluidized bed boiler hoods will be thorough and complete.

As shown in FIG. 1 to FIG. 3 , a fluidized bed boiler air cap includes an air cap cover 110 and an air inlet pipe 120 , and the air cap cover 110 is an outer cover of the air cap. Since the hood has a hood cover 110 as an outer cover, this type of hood is also known in the art as a bell hood or a sleeve hood. The air hood cover 110 is provided with an inner cavity, the upper end of the air inlet pipe 120 extends into the inner cavity of the air hood cover 110 , and a space is formed between the upper end of the air inlet pipe 120 and the inner wall of the air hood cover 110 . The annular air duct 160, the upper end of the air inlet duct 120 is provided with a plurality of air inlet holes 150 that communicate with the annular air duct 160, and the air inlet duct 120 is in fluid communication with the inner cavity of the hood cover 110 through the air inlet holes 150 at the top of the air inlet duct 120. The lower part of the hood cover 110 is provided with a number of air outlets 140 that communicate with the annular air duct 160, and the axis line of the air outlet 140 extends outward along the radial direction of the hood cover 110, and is parallel to the horizontal plane. A 40-80° downward sloping angle is formed.

As shown in FIG. 3 , (the cross section of the hood cover 110 in FIG. 3 is the cross section along the air outlet 140 , and the middle part is the cross section of the air inlet duct 120 ), each air outlet 140 is evenly distributed along the circumference of the hood cover 110 , and extend along the radial direction of the hood cover 110 . The longitudinal axis of each air outlet 140 is inclined downward, forming an included angle with the horizontal plane. That is, the longitudinal axis of each air outlet 140 is high on the inside and low on the outside. The included angle between the longitudinal axis of each air outlet 140 and the horizontal plane is 40-80°, preferably 50-70°, and most preferably 60°. Preferably, the number of air outlets 140 is even.

Further, the included angle between the axis of the air outlet 140 and the horizontal plane is 60°.

Further, the inner diameter of the hood cover 110 is φ30˜50 mm, preferably φ40 mm.

Further, the number of the air inlet holes 150 is 4 to 12, preferably 6, and the air inlet holes 150 are arranged at a distance of 5 to 10 mm, preferably 6 mm, from the top of the air inlet pipe 120 .

Further, the upper end of the air inlet pipe 120 is open, and a gap of 8-10 mm is formed between the top end of the air inlet pipe 120 and the top end of the inner wall of the hood cover 110 for air intake.

Further, the hood cover 110 and the air inlet pipe 120 are integrally formed, which is convenient for production and processing, and the overall structure is more stable.

This patent adopts a hood structure with an inner and outer double-tube structure and a downward blowing outlet. On the one hand, the fluidization reaction is more uniform, and there will be no local high-speed fluidization zone, causing the problem of rapid wear of the hood; on the other hand, the bed is completely avoided. The possibility of the material leaking into the air chamber through the air cap; none of the air caps in the prior art has an inner tube structure, and it is difficult to prevent the bed material from leaking into the air chamber through the air cap when the pipeline is operating at a low load.

The hood designed by the present invention adopts a downward blowing structure with a large inclination angle (the recommended angle is 60 degrees), and has at least 4 air outlets, and the structure is symmetrical; The problem of accelerated wear of the hood caused by this.

The air cap designed by the invention completely eliminates the phenomenon of partial uneven fluidization of the bed material, and does not cause problems such as local wear, blockage and coking of the air cap (the service life of the air cap is prolonged by about 50%), and the safety of boiler operation is greatly improved.

The above are only the preferred embodiments of the present invention, and should not limit the scope of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the new model are all It still falls within the scope of the new patent.

Claims (10)

1. An air cap for a fluidized bed boiler, characterized in that it comprises an air cap cover and an air inlet pipe, the air cap cover is provided with an inner cavity, and the upper end of the air inlet pipe extends into the inner cavity of the air cap cover, so that the An annular air duct is formed between the upper end of the air inlet duct and the inner wall of the hood cover, the upper end of the air inlet duct is provided with a number of air inlet holes that communicate with the annular air duct, and the lower part of the hood cover is provided with A plurality of air outlets communicated with the annular air duct, the axis lines of the air outlets extend outward along the radial direction of the hood cover, and form a downwardly inclined angle of 40-80° with the horizontal plane. 2 . The fluidized bed boiler air cap according to claim 1 , wherein the number of the air outlets is 4 to 12, and the circumference of all the air outlets is evenly distributed on the side wall of the air cap cover. 3 . superior. 3 . A fluidized bed boiler air cap according to claim 1 or 2 , wherein the number of the air outlets is 8. 4 . 4. A fluidized bed boiler air cap according to claim 1 or 2, characterized in that, the included angle between the axis line of the air outlet and the horizontal plane is 50-70°. 5 . The air cap of a fluidized bed boiler according to claim 1 or 2 , wherein the included angle between the axis line of the air outlet and the horizontal plane is 60°. 6 . 6 . The fluidized bed boiler air cap according to claim 1 or 2 , wherein the inner diameter of the air cap cover is 30-50 mm. 7 . 7 . The fluidized bed boiler air cap according to claim 1 or 2 , wherein the inner diameter of the air cap cover is 40 mm. 8 . 8 . The air cap for a fluidized bed boiler according to claim 1 , wherein the number of the air inlet holes is 4 to 12. 9 . 9 . The air cap of a fluidized bed boiler according to claim 1 or 8 , wherein the air inlet hole is arranged at a distance of 6 mm from the top of the air inlet pipe. 10 . 10 . The fluidized bed boiler air cap according to claim 1 or 8 , wherein a gap of 8-10 mm is formed between the top end of the air inlet pipe and the top end of the inner wall of the air cap cover. 11 .

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