Pulverized coal segregation prevention type boiler powder feeding pipeline flow guide elbow

Abstract

The utility model belongs to the coal-fired boiler powder feeding pipeline technology, and discloses a pulverized coal segregation prevention type boiler powder feeding pipeline flow guide elbow which comprises a first flow guide piece, a second flow guide piece and an elbow body, the first flow guide piece and the second flow guide piece are fixedly arranged on the inner side of the elbow body, and the width of the first flow guide piece and the width of the second flow guide piece are equal to the diameter of an elbow. An included angle alpha formed by projections of the first flow deflector and the second flow deflector on the section of the outlet of the elbow is more than 0 degree and less than 90 degrees; the elbow is used for solving the problem that pulverized coal concentration distribution at the section of an outlet of the elbow is uneven due to centrifugal force when the elbow conveys pulverized coal, effectively balances the concentration difference of the pulverized coal on the inner side and the outer side of the elbow by optimally arranging two fixed flow deflectors, and meets the requirement of an inlet concentration field of a horizontal rich-lean pulverized coal burner. The horizontal dense-thin pulverized coal burner is compact in structure, high in adaptability and suitable for being matched with the horizontal dense-thin pulverized coal burner of a boiler system of a thermal power plant.

Description

Technical Field

[0001] This utility model belongs to the technical field of coal-fired boiler pulverized coal feeding pipeline, specifically a flow guide elbow for a coal-fired boiler pulverized coal feeding pipeline that prevents pulverized coal segregation. Background Technology

[0002] In coal-fired boiler systems, the distribution characteristics of pulverized coal at the burner outlet have a significant impact on combustion efficiency and boiler operational stability. When the pulverized coal airflow turns at the 90° bend before the burner, centrifugal force causes most of the pulverized coal to adhere tightly to the outside of the bend before entering the burner, resulting in uneven pulverized coal distribution at the burner inlet cross-section. Therefore, traditional pulverized coal delivery pipe bends (referring to bends without internal structures in this article) are prone to pulverized coal segregation during pulverized coal transportation, leading to uneven pulverized coal delivery at the burner outlet and affecting boiler thermal efficiency. This is especially true if a horizontal pulverized coal burner with a rich-lean ratio is used, and the burner is designed based on a uniform gas-solid two-phase distribution of incoming pulverized coal at the flow cross-section. The pulverized coal airflow through the bend may prevent the burner from operating at its design conditions, causing the pulverized coal concentration ratio on the rich and lean sides at the burner outlet to deviate from the design expectation range.

[0003] Existing technology, Chinese patent CN219120067U, provides a pipe elbow with a guide plate. The elbow body has a hollow structure, and at least a central parallel guide plate and a vertical guide plate are provided inside the elbow body. The central parallel guide plate is located at the center of the elbow body, and the included angle of the cross-shaped guide plates is fixed. This solves the problem of turbulence caused by the significant change in the direction of water movement when the pipe elbow is located at the pump outlet; however, it cannot solve the problem of uneven coal powder delivery. Chinese patent CN118807451A discloses a dry fixed bed desulfurization device, which discloses a guide plate provided inside the elbow. The guide plate is arc-shaped and arranged along the path of the elbow. The design of the elbow and the guide plate guides and disperses the flue gas before entering the variable diameter flue, ensuring a smooth transition of the flow path. Based on its structure, it can be seen that it does not improve the uniformity of the fluid at the elbow, and may even make the uniformity lower.

[0004] Therefore, it is necessary to design a flow guide bend that can effectively prevent coal powder segregation in order to minimize the influence of the bend on the gas-solid two-phase distribution of the flow section. Utility Model Content

[0005] In order to effectively suppress the segregation of pulverized coal when passing through a 90° bend, the purpose of this utility model is to provide a pulverized coal segregation-proof boiler pulverized coal feeding pipe guide bend. By optimizing the design and arrangement of the guide vanes, the degree of segregation of pulverized coal during the transportation process within the 90° bend is reduced, thereby improving combustion uniformity and boiler thermal efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the utility model is: a guide elbow for a pulverized coal segregation-preventing boiler pulverized coal feeding pipeline, comprising a guide plate, a flange, and an elbow body. The guide plate and the guide flange are fixedly disposed on the inner side of the elbow body, and the width of the guide plate and the guide flange is equal to the diameter of the elbow. The included angle formed by the projections of the first guide plate and the second guide plate onto the elbow outlet section is... α ,0°< α <90°.

[0007] A further optimization of this utility model is that the curved surface where the guide vane 1 is located is bisected by the surface determined by the center line of the bend.

[0008] Further optimization of this utility model: included angle α The angle between the vertical plane perpendicular to the elbow's outlet section and the plane defined by the elbow's centerline is determined by the installation orientation of the elbow. α They are complementary angles.

[0009] A further optimization of this invention: the included angle formed by the guide vane and its projection on any flow section of the bend is... α .

[0010] A further optimization of this invention is that the guide vane is arc-shaped, and its curvature matches the curvature of the elbow body.

[0011] Further optimizations of this utility model: the thickness of the guide vane and the guide vane is 1 / 20 to 1 / 15 of the pipe diameter and the thickness is not less than 20 mm; the inner wall of the elbow body is smooth, and the ratio of the radius of curvature R of the elbow body to the pipe diameter D satisfies 1.4≤R / D≤2.0.

[0012] A further optimization of this utility model is that flanges are provided at both ends of the elbow body.

[0013] A further optimization of this utility model is that an "X-shaped" composite flow channel is formed between the first guide vane and the second guide vane.

[0014] Further optimizations of this utility model: the first guide vane and the second guide vane are made of wear-resistant alloy steel, and the inner wall of the elbow body is covered with a wear-resistant ceramic layer with a thickness of 4 mm to 8 mm.

[0015] A further optimization of this utility model is that a heat insulation layer is provided on the outer wall of the elbow body.

[0016] Furthermore, the curved surface where the guide vane is located is bisected by the surface determined by the center line of the bend, that is, the surface determined by the center line of the bend is the symmetric surface of the curved surface where the guide vane is located, thereby basically ensuring that the average particle concentration of coal powder on the left and right sides along the horizontal direction at the bend outlet section is equal.

[0017] Furthermore, the included angle formed by the projections of the first guide vane and the second guide vane onto the elbow outlet section... α The angle between the vertical plane perpendicular to the elbow's outlet section and the plane defined by the elbow's centerline is determined by the installation orientation of the elbow. α The angles are complementary, which allows half of the pulverized coal to be biased to the outside from the inlet of the bend, and also helps to make the pulverized coal particle concentration in the cross section on both sides relatively uniform at the outlet.

[0018] Furthermore, the included angle formed by the projections of the first guide vane and the second guide vane onto any flow cross-section of the bend is... α This reduces processing difficulty while ensuring smooth coal powder flow.

[0019] Furthermore, the guide vane is arc-shaped, and its curvature matches the curvature of the elbow body. That is, the guide vane runs along a certain longitudinal section of the elbow body to reduce the resistance to the flow of pulverized coal.

[0020] Furthermore, the thickness of the guide vane is 1 / 20 to 1 / 15 of the pipe diameter and not less than 20 mm, in order to improve the strength and service life of the guide vane.

[0021] Furthermore, the inner wall of the elbow body is smooth to reduce the frictional resistance of pulverized coal during transportation; the ratio of the elbow radius of curvature R to the pipe diameter D satisfies 1.4≤R / D≤2.0 to reduce local resistance.

[0022] Furthermore, an "X-shaped" composite flow channel is formed between the two guide vanes, which synergistically weakens the influence of centrifugal force and makes the coal powder concentration distribution more uniform.

[0023] Furthermore, the guide vane is made of wear-resistant alloy steel, and the inner surface of the elbow is covered with a wear-resistant ceramic layer with a thickness of 4 mm to 8 mm.

[0024] Furthermore, an insulation layer is provided on the outside of the elbow body to reduce heat loss.

[0025] Furthermore, flanges are welded at the inlet and outlet of the elbow to facilitate connection with upstream and downstream pipelines, and these flanges are detachable, making it easy to remove and inspect the internal working condition of the elbow during maintenance.

[0026] This utility model has at least the following beneficial technical effects:

[0027] This utility model's anti-coal pulverized coal segregation boiler pulverized coal feeding pipe guide elbow, through optimized design and arrangement of guide vanes, can effectively suppress the segregation phenomenon of coal pulverized coal during transportation, improving combustion uniformity and boiler thermal efficiency. The elbow has advantages such as simple structure, convenient use, and long service life. In addition, the elbow can be adapted to various coal qualities without adjustment mechanisms, and is especially suitable for the inlet concentration field requirements of horizontal concentrated and diluted coal pulverized coal burners. This application is used to match horizontal concentrated and diluted coal pulverized coal burners, and its function is to ensure uniform coal pulverized coal particle concentration in two equal cross sections along the horizontal direction of the burner inlet. The included angle between the two guide vanes depends on the arrangement orientation of the elbow. Attached Figure Description

[0028] Figure 1 This is an isometric schematic diagram of the present invention.

[0029] Figure 2 This is a schematic diagram of the outlet of the elbow flow channel.

[0030] Figure 3 This is a rear side view of the present invention.

[0031] Figure 4 This is a rear view schematic diagram of the present invention.

[0032] Figure 5 This is a side view of the present invention.

[0033] Figure 6 This is one type of elbow installation, characterized by an angle of 45° between the vertical plane perpendicular to the elbow outlet section and the plane defined by the elbow centerline. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0035] In the description of this utility model, it should be understood that the terms "center," "front," "left," "right," "vertical," "horizontal," "inner," "outer," "one side," "one end," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0036] This application provides a guide elbow for a pulverized coal segregation-preventing boiler pulverized coal feeding pipe, comprising a first guide plate 1, a second guide plate 2, and an elbow body 5. The first guide plate 1 and the second guide plate 2 are fixedly disposed on the inner side of the elbow body 5. The width of the first guide plate 1 and the second guide plate 2 is equal to the diameter of the elbow. The edges of the first guide plate 1 and the second guide plate 2 are connected to the inner wall of the elbow body 5. The included angle formed by the projections of the first guide plate (1) and the second guide plate (2) onto the elbow outlet section is... α ,0°< α <90°, flanges 6 are installed at both ends of the elbow body 5.

[0037] The curved surface where the first guide vane 1 is located is bisected by the plane determined by the center line of the bend. That is, the plane determined by the center line of the bend is the symmetry plane of the curved surface where the first guide vane 1 is located. This can basically ensure that the average particle concentration of coal powder on the left and right sides along the horizontal direction at the bend outlet section is equal.

[0038] To further improve the uniform mixing of pulverized coal at the elbow outlet, a flow-around structure is set near the outlet for the first guide vane 1 and the second guide vane 2. The flow-around structure is an arc-shaped protrusion with a thickness that first increases and then decreases along the pulverized coal flow direction, thus disturbing the flow state and making the mixing more uniform in the straight pipe.

[0039] The included angle formed by the projections of the first guide vane 1 and the second guide vane 2 onto the elbow outlet section α The angle between the vertical plane perpendicular to the elbow's outlet section and the plane defined by the elbow's centerline is determined by the installation orientation of the elbow. α The angles are complementary. This allows for the restriction of half of the pulverized coal to the outside from the inlet of the elbow, and also helps to ensure a relatively uniform concentration of pulverized coal particles on both sides of the outlet.

[0040] An "X-shaped" composite flow channel is formed between the two guide vanes, which works together to weaken the influence of centrifugal force and make the coal powder concentration distribution more uniform.

[0041] The included angle formed by the projections of the first guide vane 1 and the second guide vane 2 onto any flow section within the elbow body is... α To reduce the flow resistance of pulverized coal, the first guide vane 1 and the second guide vane 2 are arc-shaped, and their curvature matches the curvature of the elbow body. That is, the guide vanes are along a certain longitudinal section of the elbow body to reduce the resistance to pulverized coal flow. The inner wall of the elbow body is smooth to reduce the frictional resistance of pulverized coal during transportation. The ratio of the elbow curvature radius R to the pipe diameter D satisfies 1.4≤R / D≤2.0 to reduce local resistance.

[0042] The thickness of the guide vane is 1 / 20 to 1 / 15 of the pipe diameter, and not less than 20 mm, to improve the strength and service life of the guide vane. The guide vane is made of wear-resistant alloy steel, and the inner wall of the elbow is covered with a wear-resistant ceramic layer 6, the thickness of which is 4 mm to 8 mm. The wear-resistant ceramic layer 6 can further improve the service life of the elbow.

[0043] As a common optimization, the outer wall of the elbow body has a heat insulation layer 7 to reduce the heat loss of pulverized coal inside the elbow.

[0044] Taking a 90° elbow in front of a horizontal pulverized coal burner used in a 1000MW unit boiler as an example, the inner diameter of the elbow is 540 mm; the radius of curvature of the 90° elbow is 800 mm; the thickness of the elbow is 25 mm; the length of the straight pipe section between the elbow outlet and the horizontal pulverized coal burner is 1180 mm; the angle between the vertical plane perpendicular to the elbow outlet section and the plane determined by the elbow centerline is 45°. Figure 6 As shown.

[0045] CFD simulations show that when a traditional elbow is used (i.e., without internal structure), the pulverized coal particle concentration distribution at the burner inlet cross-section is highest in the upper right corner and lowest in other areas. Under certain operating conditions, the calculated ratio of pulverized coal particle concentration in the equal areas of the rich and lean sides at the burner inlet along the horizontal direction is 3.63. After installing the first guide vane 1 and the second guide vane 2 inside the elbow, the pulverized coal particle concentration distribution at the burner inlet cross-section becomes more uniform. Under the same calculation conditions, the ratio of pulverized coal particle concentration in the equal areas of the rich and lean sides at the burner inlet along the horizontal direction is 1.50. Therefore, the first guide vane 1 and the second guide vane 2 can essentially ensure that the average pulverized coal particle concentration on the left and right sides of the burner inlet cross-section along the horizontal direction remains relatively small. Furthermore, the first guide vane 1 restricts half of the pulverized coal from shifting outwards at the elbow inlet, and also contributes to the relative uniformity of pulverized coal particle concentration on both sides of the cross-section at the outlet.

[0046] This utility model's anti-coal pulverized coal segregation boiler pulverized coal feeding pipe guide elbow effectively reduces the segregation phenomenon of coal pulverized coal during the transportation process by optimizing the design and arrangement of the guide vanes, thereby improving combustion uniformity and boiler thermal efficiency. It has the advantages of simple structure, convenient use, and long service life.

[0047] Although the present invention has been described in detail above with general description and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A flow guide elbow for a pulverized coal feeding pipe in a boiler designed to prevent pulverized coal segregation, characterized in that, The elbow includes a first guide vane (1), a second guide vane (2), and an elbow body (5). The first guide vane (1) and the second guide vane (2) are fixedly installed on the inner side of the elbow body (5). The width of the first guide vane (1) and the second guide vane (2) is equal to the diameter of the elbow. The included angle formed by the projections of the first guide vane (1) and the second guide vane (2) onto the elbow outlet section is... α ,0°< α <90°.

2. The guide elbow for the pulverized coal feeding pipeline of the anti-pulverized coal segregation boiler according to claim 1, characterized in that, The curved surface where the first guide vane (1) is located is bisected by the surface determined by the center line of the bend.

3. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, included angle α The angle between the vertical plane perpendicular to the elbow's outlet section and the plane defined by the elbow's centerline is determined based on the elbow's installation orientation. α They are complementary angles.

4. The guide elbow for the pulverized coal feeding pipeline of the anti-pulverized coal segregation boiler according to claim 1, characterized in that, The included angle formed by the projections of the first guide vane (1) and the second guide vane (2) onto any flow section of the bend is 1 / 2. α .

5. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, The guide vane is arc-shaped, and its curvature matches the curvature of the elbow body.

6. The guide elbow for the pulverized coal feeding pipeline of the anti-pulverized coal segregation boiler according to claim 1, characterized in that: The thickness of the first guide vane (1) and the second guide vane (2) is 1 / 20 to 1 / 15 of the pipe diameter and the thickness is not less than 20 mm; the inner wall of the elbow body (5) is smooth, and the ratio of the radius of curvature R of the elbow body (5) to the pipe diameter D satisfies 1.4≤R / D≤2.

0.

7. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, Flanges (3) are provided at both ends of the elbow body (5).

8. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, An "X-shaped" composite flow channel is formed between the first guide vane (1) and the second guide vane (2).

9. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, The first guide vane (1) and the second guide vane (2) are made of wear-resistant alloy steel, and the inner wall of the elbow body (5) is covered with a wear-resistant ceramic layer with a thickness of 4 mm to 8 mm.

10. The guide elbow for the pulverized coal feeding pipeline of an anti-pulverized coal segregation boiler according to claim 1, characterized in that, A heat insulation layer (7) is provided on the outer wall of the elbow body (5).

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