Multifunctional adjustable self-protecting direct current coal powder burner

Abstract

The present application relates to a kind of multifunctional adjustable self-protection DC coal dust burner, it involves the field of coal (oil gas) power generation, it includes wind box, wind box is equipped with primary air duct and secondary air duct, the outlet end of primary air duct is arranged in the inlet end of secondary air duct, the outlet end of secondary air duct is equipped with coal dust spout, the inlet end of primary air duct and the inlet end of coal dust spout are respectively arranged in the two opposite sides of wind box, secondary air duct and coal dust spout can be moved along the axis of primary air duct to adapt to different operating conditions.The present application not only realizes the anti-overheating protection of coal dust burner during standby, but also enhances the adaptability of coal dust burner to different coal and the flexibility of operation adjustment, so that the function of coal dust burner can be expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal (oil and gas) power generation, in particular to a multifunctional adjustable self-protecting direct-flow pulverized coal burner. BACKGROUND

[0002] At present, thermal power generation is still the main source of power supply in China, among which coal-fired power plants account for the vast majority of thermal power installed capacity. It has become the normal operation of many thermal power plants to carry out deep peak regulation of thermal power units to accommodate new energy power generation. Whether in full load operation or deep peak regulation operation, part of the pulverized coal burners in the coal-fired boiler is often in standby state, and no low-temperature primary air flow is provided for these standby pulverized coal burners. Due to the radiation of high-temperature flue gas in the boiler, the overheating of the pulverized coal burner, especially the overheating and burning loss of the coal powder nozzle, is prone to occur. In some pulverized coal burners with single mill and layered combustion, due to the height difference between the two layers of burners, when standby, the phenomenon of flue gas backflowing into the burner is easy to occur, which superimposes the factors of coal powder accumulation in the pipe or the burner, causing the internal high temperature of the burner and even burning loss of the burner.

[0003] In order to avoid the above problems, the boiler operators often increase the supply amount of the peripheral air of the standby pulverized coal burner to cool and protect the burner. However, due to the small proportion of the peripheral air and the fact that it is only in the outer circle of the coal powder nozzle, the cooling effect is insufficient, and the burning loss problem of the standby layer pulverized coal burner has not been effectively solved. SUMMARY

[0004] The present application provides a multifunctional adjustable self-protecting direct-flow pulverized coal burner, which has an adjusting function, realizes good cooling protection effect, flexible adjustment of the position of the coal powder nozzle and enhances the adaptability of coal.

[0005] In order to achieve the above purpose, the technical scheme of the present application provides a multifunctional adjustable self-protecting direct-flow pulverized coal burner, which comprises an air bellow, a primary air cylinder and a secondary air cylinder are arranged in the air bellow, the outlet end of the primary air cylinder penetrates the inlet end of the secondary air cylinder, the outlet end of the secondary air cylinder is sleeved with a coal powder nozzle, the inlet end of the primary air cylinder and the inlet end of the coal powder nozzle respectively penetrate two opposite sides of the air bellow, and the secondary air cylinder and the coal powder nozzle can move axially along the primary air cylinder to adapt to different operating states.

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

[0007] Preferably, when in the working position, the primary air duct and the secondary air duct are nested with each other by a length L0 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 between the primary air duct and the secondary air duct is greater than or equal to 20 mm.

[0008] Preferably, the inlet end of the primary air duct is circular in cross section, the middle position is a square-circular segment, and the outlet end is square in cross section and gradually expanded; the inlet end of the secondary air duct is gradually expanded, and the outlet end is in the form of a Venturi tube.

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

[0010] Preferably, the positioning sleeve and the adjusting pull rod can be vertically penetrated by a positioning pin.

[0011] Preferably, the adjusting pull rod is connected to a straight-stroke pneumatic actuator outside the bellows.

[0012] Preferably, the inlet end of the primary air duct is fixedly connected to the bellows by a flange.

[0013] Preferably, the primary air duct and the secondary air duct are both provided with support wheel frames on both sides, the inside bottom of the bellows is provided with guide rails matched with the support wheel frames on both sides of the secondary air duct, and the top of the primary air duct is fixedly connected to a limiting wheel frame.

[0014] Preferably, the primary air duct is provided with a positioning stopper on the outer surface, and the end of the guide rail close to the coal powder injection port is provided with a protruding positioning block, and the protruding positioning block and the positioning stopper are used to constrain the maximum position of the forward and backward movement of the secondary air duct.

[0015] The advantage of the present application is that by adjusting, the position of the secondary air duct and the coal powder injection port assembly relative to the side of the furnace can be changed. When the coal powder burner is normally put into operation, it is in the working position; when the coal powder burner is stopped for standby, it is in the protection position. In the protection position, the coal powder injection port and the secondary air duct move backward together, away from the high-temperature flue gas of the furnace, reducing the radiation heating, and part of the secondary air flows through the inside of the secondary air duct and the coal powder injection port, preventing the backflow of high-temperature flue gas, and strengthening the cooling protection effect of the secondary air flow. The double effects of moving backward away from the high-temperature flue gas of the furnace and the enhanced cooling effect of the secondary air greatly improve the anti-overheating self-protection ability of the coal powder burner when it is stopped for standby. The forward and backward movement of the secondary air duct and the coal powder injection port can also change the position of the coal powder flow into the furnace, and then change the position of the coal powder ignition point in the furnace, achieving the purpose of adjusting the coal powder ignition and stable combustion.

[0016] The application realizes the anti-overheat protection of the coal powder burner in the standby state, enhances the adaptability of the coal powder burner to different coal types and the flexibility of operation adjustment, and expands the function of the coal powder burner. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application.

[0018] Figure 2 Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application.

[0019] Figure 3 Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application. Figure 1 Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application.

[0020] Figure 4 Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application.

[0021] Figure 1 is a front view of an embodiment of the multi-functional adjustable self-protected direct-flow coal powder burner of the application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0023] Embodiment 1

[0024] The embodiment of the application discloses a multi-functional direct-flow coal powder burner with segmented adjustment and strong protection. The multi-functional adjustable self-protected direct-flow coal powder burner is composed of a primary air cylinder 1, a support wheel frame 2, an air bellow 3, a secondary air cylinder 4, a guide rail 5, a coal powder injection port 6, an adjusting pull rod 7, a positioning sleeve 8, a positioning pin 9, a positioning stopper 10, a limiting wheel frame 11, and a fixing pin 12.

[0025] The inlet end of the primary air duct 1 is fixedly connected with the air box 3 through a flange, and a set of support wheel frames 2 are fixedly connected to the two sides of the primary air duct 1. The inlet of the primary air duct 1 is circular in cross section and is connected with a pulverized coal pipeline; the middle position is a square-circular section, and the outlet end is square in cross section and is gradually expanded. The secondary air duct 4 is fixedly connected with the pulverized coal injection port 6 through a fixing pin 12, and two sets of support wheel frames 2 are fixedly connected to the two sides of the secondary air duct 4, and a limiting wheel frame 11 is fixedly connected to the upper part of the secondary air duct 4. The inlet of the secondary air duct 4 is gradually expanded and is sleeved on the outlet of the primary air duct 1. The outlet end of the secondary air duct 4 is in the form of a Venturi tube. The front part of the guide rail 5 has a protruding positioning block fixed in the air box 3 and cooperates with the support wheel frames 2 to move and guide the secondary air duct 4 and forwardly limit the secondary air duct 4.

[0026] One end of the adjusting pull rod 7 is fixedly connected with the secondary air duct 4, and the other end passes through a positioning sleeve 8 fixedly connected with the air box 3. The adjusting pull rod 7 is provided with a plurality of through holes at intervals at a position close to the air box 3. The positioning sleeve 8 is provided with a positioning through hole with a size consistent with the through hole of the adjusting pull rod 7. A positioning pin 9 can pass through the through hole to limit and connect the positioning sleeve 8 and the adjusting pull rod 7. Positioning blocks 10 are fixedly connected to the two sides of the primary air duct 1 and are away from the inlet end of the secondary air duct 4 by a distance L.

[0027] In the present application, the secondary air duct 4 moves forward and backward along the axial direction through the rolling of the support wheel frames 2 along the guide rail 5 and the rolling of the limiting wheel frame 11 under the pushing and pulling action of the adjusting pull rod 7. When the adjusting pull rod 7 is pushed forward, the combined part of the secondary air duct 4 and the pulverized coal injection port 6 moves forward and the distance from the furnace is reduced. When the adjusting pull rod 7 is pulled backward, the combined part of the secondary air duct 4 and the pulverized coal injection port 6 moves backward and the distance from the furnace is increased. The protruding block at the front part of the guide rail 5 and the positioning blocks 10 on the two sides of the primary air duct 1 constitute a constraint for the maximum position of the forward and backward movement of the secondary air duct 4. When the secondary air duct 4 is adjusted to the required position, the positioning pin 9 is inserted into the through holes in the positioning sleeve 8 and the adjusting pull rod 7 to realize the fixing of the secondary air duct 4. The adjusting pull rod 7 is provided with a plurality of through holes corresponding 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 shown in Figure 3 When the pulverized coal burner is normally put into 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 stopped for standby, it is in the protection position, the secondary air duct 4 moves backward, 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 act as a seal, preventing too much secondary air from mixing into the primary air in advance, and preventing the primary air and pulverized coal from leaking out of the wind tube. In the protection position, the secondary wind tube 4 and the pulverized coal 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 pulverized coal nozzle 6 and then into the furnace, preventing the high-temperature flue gas from flowing back into the wind tube and enhancing the cooling protection 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 overheating self-protection ability of the pulverized coal burner when it is shut down for standby.

[0030] The forward and backward movement of the secondary air duct 4 can also cause the pulverized coal nozzle 6 to move forward and backward accordingly, thereby changing the position where the primary air and pulverized coal airflow enter the furnace, and subsequently changing the ignition point of the pulverized coal in the furnace, achieving the purpose of regulating pulverized coal ignition and stabilizing combustion. When burning low-volatile coal, the distance between the secondary air duct 4 and the furnace should be reduced to promote contact and heat exchange between the pulverized coal airflow and the high-temperature flue gas. When burning coal that easily slags, the distance between the secondary air duct 4 and the furnace should be increased to delay pulverized coal ignition and reduce the radiant heat from 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 out of service and in standby mode, and also 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] Example 2:

[0033] like Figure 4 Figure 2 shows a schematic plan view of another multifunctional, adjustable, self-protecting DC pulverized coal burner. This embodiment differs from Example 1 in that it lacks a positioning pin 9. Instead, the forward and backward movement of the adjustment lever 7 is driven by a linear pneumatic actuator 13 fixed to the wind box 3. This allows the adjustment of the secondary air duct 4 to be integrated into the power plant DCS system, enabling automatic control and facilitating remote operation by boiler operators. The remaining structure is the same as Example 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, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or 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 scope of protection 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 first-level wind tube (1) and a second-level wind tube (4) are arranged in the wind box (3), the outlet end of the first-level wind tube (1) is penetrated by the inlet end of the second-level wind tube (4), the outlet end of the second-level wind tube (4) is sleeved with a coal powder nozzle (6), the inlet end of the first-level wind tube (1) and the inlet end of the coal powder nozzle (6) are respectively penetrated by two opposite side surfaces of the wind box (3), the second-level wind tube (4) and the coal powder nozzle (6) can move axially along the first-level wind tube (1) to adapt to different operating states of normal operation or shutdown and standby; when in normal operation, they are in the working position, and when in shutdown and standby, they are in the protection position; the first-level wind tube (1) and the second-level wind tube (4) are nested with each other, and a gap is provided between the nested parts.

2. A multifunctional adjustable self-protection DC pulverized coal burner according to claim 1, characterized in that: When in the working position, the gap H1 between the nested parts 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 DC 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 DC pulverized coal burner according to claim 1, characterized in that: The bellows (3) is provided with a driving device for moving the secondary bellows (4) on the side where the inlet end of the primary bellows (1) is located. The driving device comprises a positioning sleeve (8) provided on the side of the bellows (3), and an adjusting rod (7) passing through the positioning sleeve (8) and connected to the secondary bellows (4).

6. A multifunctional adjustable self-protection DC 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 DC pulverized coal burner according to claim 5, characterized in that: The regulating rod (7) is connected to a linear pneumatic actuator (13) outside the bellows (3).

8. The multifunctional adjustable self-protection DC pulverized coal burner according to claim 1, characterized in that: The inlet end of the first-level air duct (1) is fixedly connected to the air box (3) via a flange.

9. The multifunctional adjustable self-protection DC 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 support wheel frames (2) on both sides, the inner bottom of the air box (3) is provided with guide rails (5) that cooperate with the support 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 to a limiting wheel frame (11).

10. The multifunctional adjustable self-protection DC 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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