Continuous elbow inlet device of pulverized coal burner of power station boiler

Abstract

The utility model provides a continuous elbow inlet device of a pulverized coal burner of a power station boiler, which relates to the technical field of pulverized coal burners, and comprises a first elbow, a transition pipe, a second elbow and a primary air pipe which are sequentially communicated with each other, and the bending direction of the first elbow is opposite to the bending direction of the second elbow; the first elbow, the transition pipe and the second elbow are communicated to form a continuous elbow pair, a boss used for accelerating concentration homogenization of pulverized coal airflow is arranged on the inner wall of the second elbow in a protruding mode, and the boss is located on the inner arc side of the second elbow. The device has the effect of improving the airflow uniformity of the pulverized coal.

Description

Technical Field

[0001] This application relates to the technical field of pulverized coal burners, and particularly to a continuous elbow inlet device for a pulverized coal burner of a power station boiler. Background Art

[0002] In the power industry, in order to improve the stability of pulverized coal burners of power station boilers and reduce NOx formed in the initial stage of combustion, it is necessary to separate the pulverized coal into rich and lean, and the uniformity of the pulverized coal at the inlet of the primary air pipe has an important impact on the rich-lean separation of the pulverized coal air flow, and good uniformity of the pulverized coal air flow at the inlet is often required.

[0003] Currently, traditional power station pulverized coal boilers need to undertake more peak shaving operations, and the boilers are increasingly required to operate at lower loads. In order to improve the stability of the boilers during low-load operation and enhance the safety of the boilers under low-load conditions, more and more ion ignition guns and micro-oil ignition guns are added to the pulverized coal burners of the boilers, so that the pulverized coal burners of the boilers are transformed into plasma burners and micro-oil burners. During the transformation, due to site space problems and the need for setting ion ignition guns or micro-oil ignition guns, elbows are often set at the inlet of the pulverized coal burner. However, due to the presence of the elbows, the primary air flow entering the pulverized coal burner cannot be evenly distributed in the primary air pipe, resulting in an unsatisfactory subsequent rich-lean separation effect, and thus affecting the combustion performance of the pulverized coal burner. Summary of the Utility Model

[0004] In order to improve the problem that the pulverized coal air flow entering the pulverized coal burner cannot be evenly distributed in the primary air pipe, this application provides a continuous elbow inlet device for a pulverized coal burner of a power station boiler.

[0005] The continuous elbow inlet device for a pulverized coal burner of a power station boiler provided by this application adopts the following technical solutions:

[0006] A continuous elbow inlet device for a pulverized coal burner of a power station boiler includes a first elbow, a transition pipe, a second elbow, and a primary air pipe that are connected in sequence. The bending direction of the first elbow is opposite to that of the second elbow, so that the first elbow, the transition pipe, and the second elbow are connected to form a continuous elbow pair. A convex platform for accelerating the uniformization of the pulverized coal air flow concentration is convexly provided on the inner wall of the second elbow, and the convex platform is located on the inner arc side of the second elbow.

[0007] Furthermore, the diameter of the transition pipe near the first elbow is smaller than the diameter of the transition pipe near the second elbow.

[0008] Furthermore, one side of the boss close to the transition pipe is the first guiding surface, and one side of the boss close to the primary air duct is the second guiding surface. The included angle between the first guiding surface and the central axis of the transition pipe is α, and the included angle between the second guiding surface and the central axis of the primary air duct is β. The value ranges of the included angles α and β are both 0 to 45°.

[0009] Furthermore, the bending radius of the second elbow is R2, and the distance between the edge of the second guiding surface away from the first guiding surface and the edge of the second elbow close to the primary air duct is L. The value range of L is 0 to 1 / 2R2.

[0010] Furthermore, wear-resistant layers are provided on the inner walls of the first elbow, the second elbow, and the transition pipe.

[0011] Furthermore, the boss is made of wear-resistant material.

[0012] Furthermore, a protection sleeve for air circulation is inserted into the second elbow. The length direction of the protection sleeve is the same as that of the primary air duct, and one end of the protection sleeve is outside the second elbow and the other end extends into the primary air duct. The boss is located outside the protection sleeve.

[0013] Furthermore, a wear-resistant layer is also provided on the outer wall of the protection sleeve.

[0014] Furthermore, a micro-oil ignition gun device is provided in the protection sleeve.

[0015] Furthermore, a plasma ignition gun device is provided in the protection sleeve.

[0016] In summary, the present application includes the following beneficial technical effects: When the pulverized coal air flow flows through the first elbow, the transition pipe, and the second elbow in sequence, the pulverized coal air flow will collide with the boss in the second elbow, promoting good uniformity of the pulverized coal air flow flowing into the primary air duct. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic cross-sectional structure diagram of the overall structure in the embodiment of the present application.

[0019] Figure 2 It is a schematic structure diagram of the first elbow, the transition pipe, the second elbow, the primary air duct, and the boss in the embodiment of the present application.

[0020] Figure 3 It is a three-dimensional structural schematic diagram of the first elbow, transition pipe, second elbow, primary air duct and boss in the embodiments of the present application.

[0021] Reference numerals: 1, first elbow; 2, transition pipe; 3, second elbow; 4, primary air duct; 5, boss; 6, first guiding surface; 7, second guiding surface; 8, protective casing. Detailed implementation manners

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts fall within the scope of protection of the present invention.

[0023] The embodiments of the present application disclose a continuous elbow inlet device for a pulverized coal burner of a utility boiler. Referring to Figure 1 , Figure 2 and Figure 3 , a continuous elbow inlet device for a pulverized coal burner of a utility boiler includes a first elbow 1, a transition pipe 2, a second elbow 3 and a primary air duct 4 which are connected in sequence and communicated. The first elbow 1, the transition pipe 2, the second elbow 3 and the primary air duct 4 are integrally cast to form a continuous pipeline for the pulverized coal air flow to pass through. The bending direction of the first elbow 1 is opposite to that of the second elbow 3, so that the first elbow 1, the transition pipe 2 and the second elbow 3 are connected to form a continuous elbow pair. At the same time, a boss 5 for accelerating the uniformity of the pulverized coal air flow concentration is convexly arranged on the inner wall of the second elbow 3, and the boss 5 is cast on the inner arc side of the second elbow 3. The bending radius of the first elbow 1 is R1, the bending radius of the second elbow 3 is R2, and the distance between the edge of the boss 5 close to the primary air duct 4 and the edge of the second elbow 3 close to the primary air duct 4 is L, and the value range of L is 0 to 1 / 2R2. When the pulverized coal air flow flows through the first elbow 1, the transition pipe 2 and the second elbow 3 in sequence, the pulverized coal air flow flows along the bending direction of the continuous elbow pair, and when the pulverized coal air flow flows through the second elbow 3, it will collide with the boss 5 in the second elbow 3, promoting good uniformity of the pulverized coal air flow flowing into the primary air duct 4.

[0024] To reduce the impact force received by the second elbow 3, referring to Figure 1 , Figure 2 and Figure 3, the diameter of the transition pipe 2 near one end of the first elbow 1 is smaller than the diameter of the transition pipe 2 near one end of the second elbow 3, so that when the pulverized coal air flow passes through the transition pipe 2 and reaches the boss 5, its flow velocity slows down; this can not only reduce the erosion of the inner wall of the second elbow 3 by the pulverized coal air flow, but also extend the collision time between the pulverized coal air flow and the boss 5, further promoting good uniformity of the pulverized coal air flow flowing into the primary air duct 4.

[0025] To ensure that the pulverized coal air flow can still pass through the second elbow 3 smoothly after colliding with the boss 5, referring to Figure 1 , Figure 2 and Figure 3 , one side of the boss 5 close to the transition pipe 2 is the first guiding surface 6, and one side of the boss 5 close to the primary air duct 4 is the second guiding surface 7. The included angle between the first guiding surface 6 and the central axis of the transition pipe 2 is α, and the included angle between the second guiding surface 7 and the central axis of the primary air duct 4 is β. The value ranges of the included angles α and β are both 0 to 45°. When the pulverized coal air flow passes through the boss 5, it can first collide with the first guiding surface 6, and then flow towards the second guiding surface 7 under the guiding action of the first guiding surface 6, and collide with the second guiding surface 7 again. At the same time, it smoothly flows into the primary air duct 4 under the guiding action of the second guiding surface 7, making the uniformity of the pulverized coal air flow entering the primary air duct 4 good.

[0026] Considering that when the pulverized coal air flow passes through the first elbow 1, the transition pipe 2, the second elbow 3 and the primary air duct 4 in sequence, the solid particles in the pulverized coal air flow will erode the inner walls of the first elbow 1, the transition pipe 2, the second elbow 3 and the primary air duct 4. To avoid damage to the inner walls of the first elbow 1, the transition pipe 2, the second elbow 3 and the primary air duct 4, referring to Figure 1 , Figure 2 and Figure 3 , wear-resistant layers made of wear-resistant materials are provided on the inner walls of the first elbow 1, the transition pipe 2, the second elbow 3 and the primary air duct 4, and the boss 5 is also made of wear-resistant materials. The wear-resistant materials can be wear-resistant ceramics, wear-resistant cast steel, wear-resistant silicon carbide ceramics, etc.

[0027] Referring to Figure 1 , Figure 2 and Figure 3, a protective sleeve 8 is inserted into the second elbow pipe. The length direction of the protective sleeve 8 is consistent with the length direction of the primary air pipe 4. One end of the protective sleeve 8 is located outside the second elbow 3, and the other end extends into the primary air pipe 4. The boss 5 is located outside the protective sleeve 8. To prevent the pulverized coal air flow from scouring the outer wall of the protective sleeve 8 and damaging it during flow, a wear-resistant layer is also provided on the outer wall of the protective sleeve 8. The wear-resistant layer can be a wear-resistant ceramic layer, a wear-resistant cast steel layer, a wear-resistant silicon carbide ceramic layer, etc. To help the pulverized coal burner ignite quickly, the inside of the protective sleeve 8 can be arranged as a burner center air duct, or a micro-oil ignition gun device can be set, or a plasma ignition gun device can also be set.

[0028] The implementation principle of the continuous elbow inlet device of a pulverized coal burner for a utility boiler in an embodiment of the present application is as follows: The first elbow 1, the transition pipe 2, the second elbow 3, the primary air pipe 4, the boss 5, and the protective sleeve 8 are formed by pouring molding; then the pulverized coal air flow is introduced into the first elbow 1, and then the pulverized coal air flow flows along the bending direction of the continuous bend. When the pulverized coal air flow flows through the second elbow 3, it first collides with the first guiding surface 6 of the boss 5, and then flows towards the second guiding surface 7 of the boss 5 under the guiding action of the first guiding surface 6 and collides with the second guiding surface 7 of the boss 5 again. At the same time, it smoothly flows into the primary air pipe 4 under the guiding action of the second guiding surface 7 of the boss 5, so that the pulverized coal air flow entering the primary air pipe 4 has good uniformity; finally, ignition is carried out through the ignition gun device in the protective sleeve 8, and rapid ignition of the pulverized coal burner can be achieved.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous elbow inlet device for a pulverized coal burner of a utility boiler, characterized in that, It includes a first elbow, a transition pipe, a second elbow and a primary air duct which are connected in sequence. The bending direction of the first elbow is opposite to that of the second elbow, so that the first elbow, the transition pipe and the second elbow are connected to form a continuous bend pair. A convex platform for accelerating the uniformization of the pulverized coal air flow concentration is convexly provided on the inner wall of the second elbow, and the convex platform is located on the inner arc side of the second elbow.

2. The continuous elbow inlet device of a pulverized coal burner for a utility boiler according to claim 1, wherein The diameter of the transition pipe near the first elbow is smaller than that of the transition pipe near the second elbow.

3. The continuous elbow inlet device of a pulverized coal burner for a utility boiler according to claim 2, characterized in that, One side surface of the convex platform close to the transition pipe is a first guiding surface, and one side surface of the convex platform close to the primary air duct is a second guiding surface. The included angle between the first guiding surface and the line-plane angle formed by the central axis of the transition pipe is α, and the included angle between the second guiding surface and the line-plane angle formed by the central axis of the primary air duct is β. The value ranges of the included angles α and β are both 0 to 45°.

4. The continuous elbow inlet device of a pulverized coal burner for a utility boiler according to claim 3, characterized in that, The bending radius of the second elbow is R2, and the distance between the edge of the second guiding surface far from the first guiding surface and the edge of the second elbow close to the primary air duct is L. The value range of L is 0 to 1 / 2R2.

5. A continuous elbow inlet device for a pulverized coal burner of a utility boiler according to claim 1, characterized in that, Wear-resistant layers are provided on the inner walls of the first elbow, the second elbow and the transition pipe.

6. The continuous elbow inlet device of a pulverized coal burner for a utility boiler according to claim 1, characterized in that The convex platform is made of wear-resistant material.

7. The continuous elbow inlet device of a pulverized coal burner for a power station boiler according to claim 1, characterized in that, A protection sleeve for air circulation is inserted into the second elbow. The length direction of the protection sleeve is the same as that of the primary air duct. One end of the protection sleeve is outside the second elbow, and the other end extends into the primary air duct. The convex platform is outside the protection sleeve.

8. A continuous elbow inlet device for a pulverized coal burner of a power station boiler according to claim 7, characterized in that, A wear-resistant layer is also provided on the outer wall of the protection sleeve.

9. A continuous elbow inlet device for a pulverized coal burner of a utility boiler according to claim 7, characterized in that, A micro-oil ignition gun device is provided in the protection sleeve.

10. A continuous elbow inlet device for a pulverized coal burner of a utility boiler according to claim 7, characterized in that, A plasma ignition gun device is provided in the protection sleeve.

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