Multifunctional adjustable self-protection direct-current pulverized coal burner

Abstract

The invention relates to a multifunctional adjustable self-protection direct current pulverized coal burner, which relates to the field of fire coal (oil gas) power generation, and comprises an air bellow, a first-stage air duct and a second-stage air duct are arranged in the air bellow, the outlet end of the first-stage air duct penetrates through the inlet end of the second-stage air duct, and the outlet end of the second-stage air duct is sleeved with a pulverized coal nozzle; the inlet end of the first-stage air duct and the inlet end of the pulverized coal nozzle penetrate through the two opposite side faces of the air bellow respectively, and the second-stage air duct and the pulverized coal nozzle can move in the axial direction of the first-stage air duct so as to adapt to different operation states. According to the anti-overheating protection device, anti-overheating protection of the pulverized coal burner is achieved when the pulverized coal burner is stopped for standby application, the adaptability of the pulverized coal burner to different coal types and the flexibility of operation adjustment are enhanced, and the functions of the pulverized coal burner are expanded.

Description

Technical Field

[0001] The invention relates to the field of coal (oil and gas) fired power generation, and in particular to a multifunctional adjustable self-protection direct current pulverized coal burner. Background Art

[0002] At present, thermal power generation is still the main source of electricity supply in my country, among which coal-fired power plants account for the vast majority of thermal power generation installed capacity. Deep peak regulation of thermal power units to absorb the power generation of new energy has become the normal operation of many thermal power plants. Regardless of full-load operation or deep peak regulation operation, some pulverized coal burners in coal-fired boilers are often in a shutdown and standby state. There is no low-temperature primary air flow to provide cooling for these shutdown and standby pulverized coal burners. Due to the radiation of high-temperature flue gas in the boiler furnace, it is very easy to cause overheating of the pulverized coal burner, especially the overheating and burning of the pulverized coal nozzle. In some pulverized coal burners that use single-mill stratified combustion, due to the height difference between the two layers of burners, when they are shut down and standby, it is easy for flue gas to flow back into the burner. Combined with the accumulation of powder in the pulverized coal pipeline or burner, it causes high temperature inside the burner and even ignition and burns the burner.

[0003] To avoid the above problems, boiler operators often increase the peripheral air supply of the idle pulverized coal burners to protect the burners. However, since the peripheral air volume is small and only in the outer ring of the pulverized coal nozzle, its cooling effect is insufficient, resulting in the problem of burnout of the idle pulverized coal burners not being effectively solved. Summary of the invention

[0004] The present invention provides a multifunctional adjustable self-protection direct current pulverized coal burner, which has an adjustment function, achieves a good cooling protection effect, flexibly adjusts the position of the pulverized coal nozzle and enhances the adaptability of coal types.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a multifunctional adjustable self-protection direct current pulverized coal burner, including a wind box, in which a primary wind tube and a secondary wind tube are arranged, the outlet end of the primary wind tube is penetrated through the inlet end of the secondary wind tube, the outlet end of the secondary wind tube is sleeved with a pulverized coal nozzle, the inlet end of the primary wind tube and the inlet end of the pulverized coal nozzle are respectively penetrated through two opposite side surfaces of the wind box, the secondary wind tube and the pulverized coal nozzle can move axially along the primary wind tube to adapt to different operating conditions.

[0006] Preferably, when in the working position, the gap H1 between the mutually nested parts of the primary air cylinder and the secondary air cylinder is equal everywhere.

[0007] Preferably, when in the working position, the length L0 of the mutually nested part of the primary air duct and the secondary air duct is greater than or equal to 50 mm, and the gap H1 is less than or equal to 5 mm; when in the protection position, the minimum gap H2 of the mutually nested part of the primary air duct and the secondary air duct is greater than or equal to 20 mm.

[0008] Preferably, the inlet end of the first-stage air duct is a circular cross-section, the middle position is a square-connected circle segment, and the outlet end is a square cross-section and a gradually expanding structure; the inlet end of the second-stage air duct is a gradually expanding structure, and the outlet end is a Venturi tube type structure.

[0009] Preferably, the bellows is provided with a driving device for moving the secondary bellows on the side where the inlet end of the primary bellows is located, and the driving device includes a positioning sleeve provided on the side of the bellows, and an adjusting rod passing through the positioning sleeve and connected to the secondary bellows.

[0010] Preferably, the positioning sleeve and the adjusting rod may be vertically penetrated by the same positioning pin.

[0011] Preferably, the adjusting rod is connected to a linear pneumatic actuator on the outside of the bellows.

[0012] Preferably, the inlet end of the primary air duct is fixedly connected to the wind box via a flange.

[0013] Preferably, the primary air duct and the secondary air duct are both provided with supporting wheel frames on both sides, the inner bottom of the wind box is provided with guide rails cooperating with the supporting wheel frames on both sides of the secondary air duct, and the top of the primary air duct is fixedly connected with a limiting wheel frame.

[0014] Preferably, the first-stage air duct is provided with a positioning block on the outer surface, and the end of the guide rail close to the coal powder nozzle is provided with a raised positioning block, and the raised positioning block and the positioning block are used to constrain the second-stage air duct to move forward and backward to the maximum position.

[0015] The advantage of the present invention is that the position of the secondary air duct and the pulverized coal nozzle assembly relative to the furnace side can be changed through adjustment. When the pulverized coal burner is put into operation normally, it is in the working position; when the pulverized coal burner is shut down for standby, it is in the protection position. In the protection position, the pulverized coal nozzle and the secondary air duct move backward together, away from the high-temperature flue gas in the furnace, reducing radiation heating, and part of the secondary air flows through the secondary air duct and the inside of the pulverized coal nozzle, which not only prevents the high-temperature flue gas from flowing back, but also strengthens the cooling protection effect of the secondary air flow. The dual effects of moving backward away from the high-temperature flue gas in the furnace and enhancing the cooling effect of the secondary air greatly improve the self-protection ability of the pulverized coal burner against overheating when it is shut down for standby. The forward and backward movement of the secondary air duct and the pulverized coal nozzle can also change the position of the pulverized coal airflow entering the furnace, and then change the position of the pulverized coal ignition point in the furnace, so as to achieve the purpose of adjusting the pulverized coal ignition and stable combustion.

[0016] The present invention not only realizes the overheat protection of the pulverized coal burner when it is out of service, but also enhances the adaptability of the pulverized coal burner to different types of coal and the flexibility of operation adjustment, so that the function of the pulverized coal burner can be expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic elevation view of Embodiment 1 of a multifunctional adjustable self-protecting direct current pulverized coal burner of the present invention;

[0018] Figure 2 This is a schematic plan view of Example 1 of a multifunctional adjustable self-protection DC pulverized coal burner of the present invention;

[0019] Figure 3 for Figure 1 Sectional view of the working position and protection position at A in the middle;

[0020] Figure 4 This is a schematic elevation view of Example 2 of a multifunctional adjustable self-protecting DC pulverized coal burner of the present invention.

[0021] Figure numerals: 1. primary air duct; 2. supporting wheel frame; 3. bellows; 4. secondary air duct; 5. guide rail; 6. coal powder nozzle; 7. adjusting pull rod; 8. positioning sleeve; 9. positioning pin; 10. positioning block; 11. limiting wheel frame; 12. fixing pin; 13. linear stroke pneumatic actuator. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment 1:

[0024] The embodiment of the present invention discloses a multifunctional direct current pulverized coal burner which is adjustable in sections and has strong protection. The multifunctional adjustable self-protecting direct current pulverized coal burner is composed of a primary air duct 1, a supporting wheel frame 2, a bellows 3, a secondary air duct 4, a guide rail 5, a pulverized coal nozzle 6, an adjusting pull rod 7, a positioning sleeve 8, a positioning pin 9, a positioning block 10, a limiting wheel frame 11, and a fixing pin 12.

[0025] The inlet end of the first-level wind duct 1 is fixedly connected to the wind box 3 through a flange, and a set of supporting wheel frames 2 are fixedly connected on both sides of the first-level wind duct 1. The inlet of the first-level wind duct 1 is a circular cross-section, which is connected to the coal powder pipeline; the middle position is a square-circle section, and the outlet end is a square cross-section, and it is a gradually expanding structure. The secondary wind duct 4 is fixedly connected to the coal powder nozzle 6 through a fixing pin 12, and two sets of supporting wheel frames 2 are fixedly connected on both sides, and a limiting wheel frame 11 is fixedly connected on the upper part. The inlet of the secondary wind duct 4 is a gradually expanding structure, which is outer-mounted on the outlet of the first-level wind duct 1. The outlet end of the secondary wind duct 4 is a Venturi tube type structure. There is a raised positioning block at the front of the guide rail 5, which is fixed in the wind box 3 and cooperates with the supporting wheel frame 2 to play a role in moving guide and forward limiting the secondary wind duct 4.

[0026] One end of the adjusting rod 7 is fixedly connected to the secondary air duct 4, and the other end passes through the positioning sleeve 8 fixedly connected to the wind box 3. The adjusting rod 7 is provided with a plurality of through holes spaced at a certain distance near the wind box 3. The positioning sleeve 8 is provided with a positioning through hole of the same size as the opening of the adjusting rod 7. The positioning pin 9 can pass through the through hole to limit the positioning sleeve 8 and the adjusting rod 7. The positioning block 10 is fixedly connected to both sides of the primary air duct 1, and is at a distance L from the inlet end of the secondary air duct 4.

[0027] In the present invention, the secondary air duct 4, under the push-pull action of the adjusting rod 7, realizes forward and backward movement along the axial direction through the rolling of the supporting wheel frame 2 along the guide rail 5 and the rolling of the limiting wheel frame 11. When the adjusting rod 7 is pushed forward, the assembly of the secondary air duct 4 and the pulverized coal nozzle 6 will move forward, and the distance from the furnace will be reduced. When the adjusting rod 7 is pulled backward, the assembly of the secondary air duct 4 and the pulverized coal nozzle 6 will move backward, and the distance from the furnace will be increased. The front protrusion of the guide rail 5 and the positioning blocks 10 on both sides of the primary air duct 1 constitute a constraint on the maximum forward and backward movement position of the secondary air duct 4. When the secondary air duct 4 is adjusted to the desired position, the positioning pin 9 is inserted into the through holes on the positioning sleeve 8 and the adjusting rod 7 to fix the secondary air duct 4. The adjusting rod 7 is provided with a plurality of through holes, which can correspond to different positions of the secondary air duct 4.

[0028] The relative positions of the primary air duct 1 and the secondary air duct 4 are as follows: Figure 3 When the pulverized coal burner is in normal operation, it is in the working position, the distance between the primary air duct 1 and the secondary air duct 4 is H1, and the covering distance is L0; when the pulverized coal burner is out of service, it is in the protection position, the secondary air duct 4 moves back, and the gap distance between the two air ducts is H2. Preferably, L0≥50mm, H1≤5mm, and H2≥20mm.

[0029] In the working position, the smaller H1 gap and the secondary air in the wind box 3 play a sealing role, avoiding too much secondary air from mixing into the primary air in advance, and preventing the primary air and coal powder from leaking out of the wind tube. In the protection position, the secondary wind tube 4 and the coal powder nozzle 6 move backward together, away from the high-temperature flue gas in the furnace, reducing radiation heating, and the larger gap distance H2 allows part of the secondary air in the wind box 3 to flow into the secondary wind tube 4 and the coal powder nozzle 6 and then enter the furnace, which not only prevents the high-temperature flue gas from flowing back into the wind tube, but also enhances the cooling protection effect of the secondary air from the inside. The dual effects of moving backward away from the high-temperature flue gas in the furnace and enhancing the cooling effect of the secondary air greatly improve the anti-overheating self-protection ability of the coal powder burner when it is shut down for standby.

[0030] The forward and backward movement of the secondary air duct 4 can correspondingly realize the forward and backward movement of the pulverized coal nozzle 6, thereby changing the position of the primary air and pulverized coal airflow entering the furnace, and then changing the position of the pulverized coal ignition point in the furnace, so as to achieve the purpose of regulating the ignition and stable combustion of pulverized coal. When burning coal with low volatility, it is advisable to reduce the distance between the secondary air duct 4 and the furnace to promote the contact and heat exchange between the pulverized coal airflow and the high-temperature flue gas; when burning coal that is easy to slag, it is advisable to increase the distance between the secondary air duct 4 and the furnace to delay the ignition of pulverized coal and reduce the radiation heat of the high-temperature flue gas on the pulverized coal nozzle 6.

[0031] The present invention adjusts the front and rear positions of the secondary air duct 4 and the pulverized coal nozzle 6 assembly, thereby achieving overheat protection for the pulverized coal burner when it is shut down for standby use, and enhancing the adaptability of the pulverized coal burner to different types of coal and the flexibility of operation adjustment, thereby expanding the function of the pulverized coal burner.

[0032] Embodiment 2:

[0033] like Figure 4 As shown, it is a plan view of another multifunctional adjustable self-protection direct current pulverized coal burner. The difference between this embodiment and embodiment 1 is that there is no positioning pin 9, and the forward and backward push-pull movement of the adjustment rod 7 is driven by the straight-stroke pneumatic actuator 13 fixed on the wind box 3, so that the adjustment of the secondary wind tube 4 can be incorporated into the power plant DCS system to achieve automatic control, which is convenient for remote operation of boiler operators. Other structures are the same as embodiment 1.

[0034] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multifunctional adjustable self-protection DC pulverized coal burner, characterized in that: The invention comprises a wind box (3), wherein a primary wind tube (1) and a secondary wind tube (4) are arranged inside the wind box (3); the outlet end of the primary wind tube (1) passes through the inlet end of the secondary wind tube (4); the outlet end of the secondary wind tube (4) is sleeved with a coal powder nozzle (6); the inlet end of the primary wind tube (1) and the inlet end of the coal powder nozzle (6) are respectively passed through two opposite side surfaces of the wind box (3); the secondary wind tube (4) and the coal powder nozzle (6) can move axially along the primary wind tube (1) to adapt to different operating conditions.

2. A multifunctional adjustable self-protection direct current pulverized coal burner according to claim 1, characterized in that: When in the working position, the gap H1 between the mutually nested parts of the primary air duct (1) and the secondary air duct (4) is equal everywhere.

3. A multifunctional adjustable self-protection DC pulverized coal burner according to claim 2, characterized in that: When in the working position, the length L0 of the mutually nested portion of the primary air duct (1) and the secondary air duct (4) is greater than or equal to 50 mm, and the gap H1 is less than or equal to 5 mm; when in the protection position, the minimum gap H2 of the mutually nested portion of the primary air duct (1) and the secondary air duct (4) is greater than or equal to 20 mm.

4. A multifunctional adjustable self-protection direct current pulverized coal burner according to claim 3, characterized in that: The inlet end of the first-stage air duct (1) is a circular cross-section, the middle position is a square-connected circle segment, and the outlet end is a square cross-section and a gradually expanding structure; the inlet end of the second-stage air duct (4) is a gradually expanding structure, and the outlet end is a Venturi tube-type structure.

5. The multifunctional adjustable self-protection direct current pulverized coal burner according to claim 1, characterized in that: The wind box (3) is provided with a driving device for moving the secondary wind tube (4) on the side where the inlet end of the primary wind tube (1) is located, and the driving device includes a positioning sleeve (8) provided on the side of the wind box (3), and an adjusting rod (7) passing through the positioning sleeve (8) and connected to the secondary wind tube (4).

6. A multifunctional adjustable self-protection direct current pulverized coal burner according to claim 5, characterized in that: The positioning sleeve (8) and the adjusting pull rod (7) may be vertically penetrated by a common positioning pin (9).

7. The multifunctional adjustable self-protection direct current pulverized coal burner according to claim 5, characterized in that: The adjusting pull rod (7) is connected to a linear-stroke pneumatic actuator (13) outside the bellows (3).

8. The multifunctional adjustable self-protection direct current pulverized coal burner according to claim 1, characterized in that: The inlet end of the primary air cylinder (1) is fixedly connected to the wind box (3) via a flange.

9. The multifunctional adjustable self-protection direct current pulverized coal burner according to claim 1, characterized in that: The first-stage air duct (1) and the second-stage air duct (4) are both provided with supporting wheel frames (2) on both sides, the inner bottom of the air box (3) is provided with guide rails (5) that cooperate with the supporting wheel frames (2) on both sides of the second-stage air duct (4), and the top of the first-stage air duct (1) is fixedly connected with a limiting wheel frame (11).

10. A multifunctional adjustable self-protection direct current pulverized coal burner according to claim 9, characterized in that: The first-stage air duct (1) is provided with a positioning block (10) on its outer surface, and the end of the guide rail (5) close to the coal powder nozzle (6) is provided with a raised positioning block, and the raised positioning block and the positioning block (10) are used to constrain the second-stage air duct (4) to move forward and backward to a maximum position.

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