Ultra-low load grid nozzle center strong ignition fuel-rich burner

Abstract

The invention discloses an ultra-low load grid nozzle center strong ignition fuel-rich burner, and belongs to the technical field of burners. The problem that an existing burner structure cannot guarantee stable and continuous powder supply of a boiler under ultra-low load, and consequently stable ignition and combustion of pulverized coal cannot be guaranteed is solved. Comprising an elbow, a cylinder and a square pipe which are sequentially communicated and fixedly connected end to end, a negative pressure nozzle penetrates through the cylinder, the inlet end of the negative pressure nozzle faces the elbow, the negative pressure nozzle penetrates through the cylinder in an axial sliding mode through an adjusting assembly, a concentrated powder pipe is fixedly arranged in the square pipe, and the outlet end of the concentrated powder pipe is fixedly connected with a grid nozzle in a communicated mode. And by arranging the negative pressure nozzle, the adherence effect when the pulverized coal passes through the elbow is effectively solved, and the pulverized coal is concentrated towards the middle under the action of negative pressure. Real-time adjustment of the ratio of the thick pulverized coal to the thin pulverized coal is achieved by simply adjusting the position of the negative pressure nozzle, and therefore it is guaranteed that the boiler can still supply pulverized coal stably and continuously when the load is ultra-low, and stable ignition and combustion of the pulverized coal are guaranteed.

Description

Technical Field

[0001] The invention relates to an ultra-low load grid nozzle central strong ignition fuel-rich burner, belonging to the technical field of burners. Background Art

[0002] Existing burners cannot meet the requirements of deep peak load regulation. Specifically, due to the development of renewable energy, the peak load regulation capacity of power station boilers is required to be higher, while the existing thick-lean burners are difficult to achieve stable combustion without oil injection at 20% load of the boiler, which greatly limits the peak load regulation capacity of the boiler;

[0003] The existing primary air nozzle structure is unreasonable. Specifically, some burners only pay attention to the primary concentration effect of the thick-lean separation device, but do not give enough consideration to the secondary concentration effect of the primary air nozzle and its downstream recirculation zone, resulting in the burner failing to achieve the ideal stable combustion effect and low nitrogen oxide emission performance.

[0004] In addition, the existing burner structure cannot adjust the ratio of concentrated coal powder to thin coal powder, and thus cannot ensure that the boiler can still stably and continuously supply powder at ultra-low load, and thus cannot ensure stable ignition and combustion of coal powder.

[0005] Therefore, there is an urgent need to improve the burner structure so that it can maintain stable combustion below 20% load. Summary of the invention

[0006] The present invention aims to solve the problem that the existing burner structure cannot ensure that the boiler can still stably and continuously supply pulverized coal at ultra-low load, resulting in the inability to ensure stable ignition and combustion of coal powder, and further provides an ultra-low load grid nozzle center strong ignition and rich fuel burner.

[0007] The technical solution adopted by the present invention to solve the above technical problems is:

[0008] An ultra-low load grid nozzle center strong ignition fuel-rich burner includes an elbow, a cylinder and a square tube which are connected and fixed in sequence end to end, wherein a negative pressure nozzle is installed in the cylinder, the inlet end of the negative pressure nozzle is arranged toward the elbow, the negative pressure nozzle is axially slidably installed in the cylinder through an adjusting component, a concentrated powder pipe is fixed in the square tube, and the outlet end of the concentrated powder pipe is connected and fixed with the grid nozzle.

[0009] Furthermore, the negative pressure nozzle is a conical cylindrical structure, the large diameter end of which is the inlet end, and the small diameter end is the outlet end.

[0010] Furthermore, the adjustment assembly includes a sealing sleeve, a sliding sleeve, a connecting rod, a toothed plate and a motor, wherein a first limiting long hole is opened on the cylinder, the sealing sleeve and the sliding sleeve are coaxially mounted on the outside of the cylinder and the sealing sleeve cover is arranged on the outside of the sliding sleeve, the connecting rod is inserted into the first limiting long hole and its two ends are respectively fixedly connected to the inner wall of the sliding sleeve and the outer wall of the negative pressure nozzle, a second limiting long hole is opened on the sealing sleeve, the toothed plate is axially fixedly mounted on the outer wall of the sliding sleeve and slidably inserted into the second limiting long hole, and the motor is fixedly arranged on the outside of the cylinder and engages with the toothed plate through the gear to drive the negative pressure nozzle to move axially.

[0011] Furthermore, the concentrated powder pipe comprises a wide section, a transition section and a narrow section which are sequentially connected and fixed along a direction from the inlet to the outlet.

[0012] Furthermore, the grid nozzle includes a nozzle body and a plurality of combustion stabilizing teeth fixed at the outlet end of the coal powder channel inside the nozzle body, wherein the plurality of combustion stabilizing teeth are respectively arranged at the upper and lower parts of the nozzle body, and the upper combustion stabilizing teeth and the lower combustion stabilizing teeth are staggered along their distribution direction.

[0013] Furthermore, the exterior of the nozzle body is of a gradually expanding structure along the coal powder spraying direction.

[0014] Furthermore, the concentrated powder tube is coaxially arranged with the square tube.

[0015] Furthermore, the cylinder and the negative pressure nozzle are coaxially arranged.

[0016] Furthermore, the cylinder and the square tube are connected and fixedly coupled via a square-to-circle transition piece.

[0017] Furthermore, the corners of the square tube are rounded.

[0018] Compared with the prior art, the present invention has the following effects:

[0019] The ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention realizes real-time adjustment of the thick and thin coal powder ratio by simply adjusting the position of the negative pressure nozzle during the operation of the boiler, thereby ensuring that the boiler can still stably and continuously supply coal powder at ultra-low load, thereby ensuring stable ignition and combustion of coal powder. At ultra-low load, due to the increase in coal powder concentration on the thick coal powder side of the burner, the boiler is not easy to extinguish, and can continue to operate stably, reducing the number of boiler starts and stops.

[0020] In the ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention, by arranging a negative pressure nozzle, the wall-adhering effect of coal powder when passing through the elbow is effectively solved, so that the coal powder is concentrated in the middle under the action of negative pressure.

[0021] In the ultra-low load grid nozzle center strong ignition rich fuel burner of the present invention, by arranging the grid nozzle, the rich side coal powder of the boiler is evenly distributed at ultra-low load, the ignition and combustion are good, and the formation of outlet black dragon is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a perspective schematic diagram of an ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention;

[0024] Figure 2 It is a left side schematic diagram of an ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention (elbow is not shown);

[0025] Figure 3 It is a main cross-sectional schematic diagram of an adjustment assembly in an ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention;

[0026] Figure 4 It is a side cross-sectional schematic diagram of an adjustment assembly in an ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention;

[0027] Figure 5 It is a schematic diagram of the structure of the concentrated powder tube.

[0028] In the figure:

[0029] 1. Elbow; 2. Cylinder; 21. First limit long hole; 3. Square tube; 4. Negative pressure nozzle; 5. Adjustment assembly; 51. Sealing sleeve; 52. Sliding sleeve; 53. Connecting rod; 54. Toothed plate; 6. Concentrated powder tube; 61. Wide section; 62. Transition section; 63. Narrow section; 7. Grid nozzle; 71. Nozzle body; 72. Combustion stabilizing tooth; 8. Square-round transition piece. DETAILED DESCRIPTION

[0030] Specific implementation method 1: Combination Figure 1 to Figure 5 The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] It should be noted that the descriptions of the present invention regarding directions such as "front", "back", "left", "right", "inside", "outside", "left side", "right side", "upper", "lower", "top", "bottom", etc. are all defined based on the relationship between the orientations or positions shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In the description of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0032] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] An ultra-low load grid nozzle center strong ignition fuel-rich burner comprises an elbow 1, a cylinder 2 and a square tube 3 which are connected and fixed in sequence end to end, wherein a negative pressure nozzle 4 is installed in the cylinder 2, the inlet end of the negative pressure nozzle 4 is arranged toward the elbow 1, and the negative pressure nozzle 4 is axially slidably installed in the cylinder 2 through an adjustment component 5, a concentrated powder pipe 6 is fixed in the square tube 3, and the outlet end of the concentrated powder pipe 6 is connected and fixed with a grid nozzle 7.

[0034] The primary air pulverized coal enters through the inlet end of the elbow 1. By utilizing the elbow 1 effect, the pulverized coal concentration on the inner arc side of the elbow 1 is higher, and the pulverized coal concentration on the outer arc side of the elbow 1 is lower, thereby achieving thick and thin separation. This principle is an existing technology and will not be repeated here.

[0035] By providing the negative pressure nozzle 4, the wall-adhering effect of the coal powder when passing through the elbow 1 is effectively solved, so that the coal powder is concentrated in the middle under the action of the negative pressure.

[0036] The outlet end of the negative pressure nozzle 4 is arranged toward the thick powder pipe 6, a thick powder channel is formed in the thick powder pipe 6, and a thin powder channel is formed between the outer side of the thick powder pipe 6 and the inner side of the square tube 3. The position of the negative pressure nozzle 4 in the cylinder 2 is adjusted by adjusting the component 5, and the distance between the outlet end of the negative pressure nozzle 4 and the inlet end of the thick powder channel is adjusted, thereby adjusting the thick and thin coal powder ratio, so that the boiler can still stably connect to the powder supply at ultra-low load, ensuring the stable ignition and combustion of the coal powder.

[0037] By arranging the grid nozzle 7, the pulverized coal on the concentrated side of the boiler is evenly distributed at ultra-low load, ignites and burns well, and the formation of black dragon at the outlet is avoided.

[0038] The outlet end of the square tube 3 is fixed with a conical expansion opening.

[0039] The ultra-low load grid nozzle center strong ignition fuel-rich burner of the present invention realizes real-time adjustment of the thick and thin coal powder ratio by simply adjusting the position of the negative pressure nozzle 4 during the operation of the boiler, thereby ensuring that the boiler can still stably and continuously supply coal powder at ultra-low load, thereby ensuring stable ignition and combustion of coal powder. At ultra-low load, due to the increase in coal powder concentration on the thick coal powder side of the burner, the boiler is not easy to extinguish, and can continue to operate stably, reducing the number of boiler starts and stops.

[0040] The negative pressure nozzle 4 is a conical cylindrical structure, with the large diameter end being the inlet end and the small diameter end being the outlet end. With such a design, the conical cylindrical structure enables the negative pressure nozzle 4 itself to have a negative pressure function. After the air-powder mixture passes through the elbow 1, when it passes through the conical cylindrical structure at high speed, the speed is further increased, and negative pressure is formed at the outlet end. The negative pressure nozzle 4 is a primary shrinkage of the air-powder mixture.

[0041] The adjustment component 5 includes a sealing sleeve 51, a sliding sleeve 52, a connecting rod 53, a toothed plate 54 and a motor, wherein a first limiting long hole 21 is opened on the cylinder 2, the sealing sleeve 51 and the sliding sleeve 52 are coaxially sleeved on the outside of the cylinder 2 and the sealing sleeve 51 is covered on the outside of the sliding sleeve 52, the connecting rod 53 is inserted into the first limiting long hole 21 and its two ends are respectively fixedly connected to the inner wall of the sliding sleeve 52 and the outer wall of the negative pressure nozzle 4, a second limiting long hole is opened on the sealing sleeve 51, the toothed plate 54 is axially fixed on the outer wall of the sliding sleeve 52 and slidably inserted into the second limiting long hole, the motor is fixedly arranged on the outside of the cylinder 2 and meshes with the toothed plate 54 through the gear to drive the negative pressure nozzle 4 to move axially.

[0042] The toothed plate 54 may also be a rack, as long as it can mesh with the gear to drive the sliding sleeve 52 to move axially.

[0043] The motor can be fixed in the outer space of the cylinder 2 or outside the cylinder 2 by a bracket or any other means.

[0044] The first position-limiting long hole 21 and the second position-limiting long hole are both opened along the axial direction of the negative pressure nozzle 4, that is, the length direction of the first position-limiting long hole 21 and the length direction of the second position-limiting long hole are parallel to the axial direction of the negative pressure nozzle 4. The connecting rod 53 can be round steel. The number of connecting rods 53 can be one, two or more. The number and position of the first position-limiting long holes 21 are set in a one-to-one correspondence with the connecting rods 53. The number of toothed plates 54 can be one or two, preferably two, and they are arranged symmetrically about the central axis of the sliding sleeve 52 to effectively avoid the occurrence of jamming or even jamming due to axis offset during the position adjustment of the negative pressure nozzle 4. The number and position of the second position-limiting long holes are set in a one-to-one correspondence with the toothed plates 54. When the number of connecting rods 53 is two or more, they are evenly distributed along the circumferential direction. A gear is fixed on the motor output shaft, and the gear meshes with the toothed plate 54. The motor controls the gear to rotate, thereby driving the toothed plate 54 and the sliding sleeve 52 fixed thereto to move axially along the negative pressure nozzle 4. The sliding sleeve 52 drives the connecting rod 53 to move in the first limiting long hole 21, thereby driving the negative pressure nozzle 4 to achieve axial position adjustment.

[0045] The sealing sleeve 51 is arranged on the outside of the sliding sleeve 52 to play a sealing role, that is, to seal the sliding sleeve 52, the connecting rod 53 and other structures to prevent the coal powder from leaking out.

[0046] The concentrated powder pipe 6 includes a wide section 61, a transition section 62 and a narrow section 63 which are connected and fixed in sequence from the inlet to the outlet. In this design, the concentrated powder pipe 6 forms a secondary contraction by setting the transition section 62, further ensuring the jet velocity of the proportioned coal powder of the concentrated coal powder under ultra-low load.

[0047] The grid nozzle 7 includes a nozzle body 71 and a plurality of combustion stabilizing teeth 72 fixed at the outlet end of the coal powder channel inside the nozzle body 71, wherein the plurality of combustion stabilizing teeth 72 are respectively arranged at the upper and lower parts of the nozzle body 71, and the upper combustion stabilizing teeth 72 and the lower combustion stabilizing teeth 72 are staggered along their distribution direction. Such a design increases the disturbance at the outlet end of the coal powder, makes the coal powder evenly distributed, and prevents the coal powder from being sucked into the nozzle. The radial cross-sectional tooth size of the coal powder channel inside the nozzle body 71 is the same as the radial cross-sectional tooth size of the concentrated powder channel in the narrow pipe section of the concentrated powder pipe 6.

[0048] The outside of the nozzle body 71 is a gradually expanding structure along the coal powder spraying direction. With this design, the radial cross section of the coal powder channel inside the nozzle body 71 is rectangular, and the outside of the nozzle body 71 is a four-sided pyramid segment structure, that is, the axial cross section of the nozzle body 71 is trapezoidal. The external shape of the nozzle body 71 with a gradually expanding structure further prevents the coal powder from being sucked into the nozzle.

[0049] The concentrated powder tube 6 is coaxially arranged with the square tube 3 .

[0050] The cylinder 2 and the negative pressure nozzle 4 are coaxially arranged.

[0051] The cylinder 2 and the square tube 3 are connected and fixedly connected by a square-round transition piece 8. With such a design, the specific structure of the square-round transition piece 8 is a conventional joint structure for connecting the square tube 3 and the round tube, which will not be described in detail here.

[0052] The corners of the square tube 3 are rounded. In this design, by rounding the square tube 3, i.e. adopting the rounded square tube 3, the right-angle wall effect on the light coal powder side can be effectively solved, so that the outlet distribution of the light coal powder is more uniform, thereby improving the burnout rate on the light coal powder side.

[0053] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ultra-low load grid nozzle center strong ignition fuel-rich burner, characterized in that: The invention comprises an elbow (1), a cylinder (2) and a square tube (3) which are connected and fixed in sequence end to end, wherein a negative pressure nozzle (4) is installed in the cylinder (2), the inlet end of the negative pressure nozzle (4) is arranged toward the elbow (1), the negative pressure nozzle (4) is axially slidably installed in the cylinder (2) through an adjustment component (5), a concentrated powder tube (6) is fixed in the square tube (3), and the outlet end of the concentrated powder tube (6) is connected and fixedly connected to a grid nozzle (7).

2. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The negative pressure nozzle (4) is a conical cylindrical structure, with a large diameter end being an inlet end and a small diameter end being an outlet end.

3. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The adjustment assembly (5) comprises a sealing sleeve (51), a sliding sleeve (52), a connecting rod (53), a toothed plate (54) and a motor, wherein a first limiting long hole (21) is provided on the cylinder (2), the sealing sleeve (51) and the sliding sleeve (52) are coaxially sleeved on the outside of the cylinder (2), and the sealing sleeve (51) is covered on the outside of the sliding sleeve (52), the connecting rod (53) is inserted into the first limiting long hole (21), and its two ends are respectively fixedly connected to the inner wall of the sliding sleeve (52) and the outer wall of the negative pressure nozzle (4), the sealing sleeve (51) is provided with a second limiting long hole, the toothed plate (54) is fixedly mounted on the outer wall of the sliding sleeve (52) along the axial direction and slidably inserted into the second limiting long hole, and the motor is fixedly arranged on the outside of the cylinder (2) and meshes with the toothed plate (54) through a gear, thereby driving the negative pressure nozzle (4) to move axially.

4. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The concentrated powder pipe (6) comprises a wide section (61), a transition section (62) and a narrow section (63) which are sequentially connected and fixed from the inlet to the outlet.

5. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The grid nozzle (7) comprises a nozzle body (71) and a plurality of combustion stabilizing teeth (72) fixedly arranged at the outlet end of the coal powder channel inside the nozzle body (71), wherein the plurality of combustion stabilizing teeth (72) are respectively arranged at the upper part and the lower part of the nozzle body (71), and the upper combustion stabilizing teeth (72) and the lower combustion stabilizing teeth (72) are staggered along their distribution direction.

6. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The exterior of the nozzle body (71) is of a gradually expanding structure along the coal powder spraying direction.

7. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The concentrated powder tube (6) is coaxially arranged with the square tube (3).

8. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The cylinder (2) and the negative pressure nozzle (4) are coaxially arranged.

9. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The cylinder (2) and the square tube (3) are connected and fixedly connected via a square-to-circle transition piece (8).

10. The ultra-low load grid nozzle center strong ignition fuel-rich burner according to claim 1, characterized in that: The corners of the square tube (3) are rounded.

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