Anti-ash-blocking system for flue of industrial boiler

Abstract

The utility model relates to the technical field of flue waste heat utilization devices, in particular to an industrial boiler flue anti-ash-blocking system which comprises a flue and a tubular air preheater arranged in the flue, and further comprises a steam ash blowing pipe which is communicated with a medium-pressure steam pipeline and arranged on the flue located on the upper portion of the tubular air preheater. The steel ash hopper is connected between the vertical section and the horizontal section of the flue, and the steel ash hopper is in a conical barrel shape with an upper opening and a lower opening; the nozzles are arranged on the peripheral side of the steel ash bucket; and the ash water recycling pool is communicated with the lower opening of the steel ash hopper through an ash water discharging pipeline. According to the anti-ash-blocking system, ash blown down by the tubular air preheater and falling ash in smoke can be collected into the steel ash hopper in the operation period and the maintenance period and discharged into the ash water recycling pool, smoothness of a smoke channel at the tail of a boiler is guaranteed, the circulation resistance of the smoke is reduced, and the service life of the boiler is prolonged. The long-period continuous operation of the air preheater is effectively guaranteed, and meanwhile the dust removal load of the flue gas downstream dust remover is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of flue waste heat utilization devices, in particular to an industrial boiler flue ash blocking prevention system. Background Art

[0002] In the design of industrial boilers, tubular air preheaters are widely used because of their high heat exchange efficiency, low air leakage rate, simple structure, and convenient maintenance. However, since tubular air preheaters are arranged at the end of the heating surface at the rear of the boiler, the flue gas temperature at this location is low, the flue gas contains a large amount of water vapor, and the flue gas is close to the acid dew point. The wet steam combines with dust particles to form wet ash. During operation, the smoke particles are easy to adhere to the outer wall of the tubular air preheater tube bundle and the bottom of the flue. The accumulated wet ash is also easy to adhere and harden, which hinders the heat transfer of the heat exchange tube, causing the exhaust gas temperature at the outlet of the tubular air preheater to increase, the exhaust heat loss to increase, and the boiler efficiency to decrease. In addition, the outlet of the tubular air preheater is a horizontal flue. During operation, the fallen ash at the lower part of the air preheater outlet will gradually accumulate and harden on the horizontal flue. This makes the flow area of ​​the flue smaller, increases the flow resistance of the flue gas, and in severe cases will reduce the output of the boiler. Therefore, the ash blocking problem of the flue of the industrial boiler tubular air preheater is a major hidden danger to the safe and economical operation of industrial boilers. Utility Model Content

[0003] In order to solve at least one of the above-mentioned technical problems, the utility model proposes an industrial boiler flue ash blocking prevention system, which arranges a conical steel ash hopper between the vertical section and the horizontal section of the industrial boiler flue, so that the accumulated ash blown off by the steam soot blowing pipe from the tubular heat exchanger slides down from the slope inner wall of the conical steel ash hopper, and at the same time, the high-pressure water sprayed from the nozzle disperses the compacted ash accumulated at the bottom of the steel ash hopper and discharges it from the lower port to the return water recovery pool, thereby solving the problem that ash is easy to accumulate and difficult to clean in the horizontal flue at the lower port of the tubular air preheater, resulting in large smoke flow resistance and affecting the normal operation of the boiler.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] An industrial boiler flue ash blocking prevention system includes a flue and a tubular air preheater arranged in the flue, and also includes:

[0006] A steam soot blowing pipe, which is used to blow away the soot deposited on the heat exchange tubes of the tubular air preheater, the steam soot blowing pipe is connected to the medium-pressure steam pipeline and is arranged in the flue located at the upper part of the tubular air preheater;

[0007] A steel ash hopper is connected between the vertical section and the horizontal section of the flue, and the steel ash hopper is in the shape of a cone barrel with upper and lower openings, and the upper opening of the steel ash hopper faces the vertical section;

[0008] A nozzle, which is used to flush the hardened ash attached to the inner wall of the steel ash hopper, the nozzle is arranged around the steel ash hopper, and the nozzle is connected to the high-pressure flushing pipeline;

[0009] The ash water recovery tank is connected with the lower opening of the steel ash hopper through an ash water discharge pipeline.

[0010] Preferably, the tubular air preheater includes a high-temperature air chamber connected to the air outlet of the upper heat exchange tube, a low-temperature air chamber connected to the air inlet of the lower heat exchange tube, and a turning air chamber connected to the air inlet of the upper heat exchange tube and the air outlet of the lower heat exchange tube; the high-temperature air chamber and the low-temperature air chamber are located on the same side of the flue, and the turning air chamber is located on the opposite side of the high-temperature air chamber.

[0011] Preferably, the nozzle is directed toward the bottom of the steel ash hopper.

[0012] Preferably, a compressed air pipeline is provided at the inlet of the flue and located at the upper part of the tubular air preheater, and a compressed air valve is provided on the compressed air pipeline.

[0013] Preferably, the steam soot blowing pipe is telescopic.

[0014] Preferably, the medium-pressure steam pipeline and the high-pressure flushing water pipeline are respectively provided with a first valve and a second valve, and the ash discharge water pipeline is respectively provided with a third valve and a fourth valve near the lower opening of the steel ash hopper and near the inlet of the ash water recovery tank.

[0015] Preferably, the pressure of the high-pressure flushing pipeline is not less than 1.2 MPa.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The utility model arranges a conical steel ash hopper between the vertical section and the horizontal section of the industrial boiler flue, so that the accumulated ash swept by the steam soot blowing pipe from the tubular heat exchanger slides down from the inner wall of the slope of the conical steel ash hopper. At the same time, the flue gas forms a vortex after entering the conical steel ash hopper, and the smoke dust particles in the flue gas are disturbed and collided, so that the flue gas flow energy is lost, and large particles of dust and water droplets fall into the steel ash hopper. The high-pressure water sprayed by the nozzle disperses the smoke dust accumulated and hardened at the bottom of the steel ash hopper and is discharged from the lower port to the return water recovery pool, so that the accumulated ash in the horizontal flue at the lower port of the tubular air preheater is easy to discharge and clean, thereby ensuring the smooth flow of the flue at the tail end of the boiler, reducing the resistance of the smoke in the flue, and making the tubular air preheater effectively operate for a long period of time, and also reducing the dust removal load of the dust collector downstream of the flue gas.

[0018] The utility model arranges the third valve and the fourth valve at the lower opening of the steel ash hopper and the inlet of the ash water recovery pool. During the operation of the boiler, the third valve and the fourth valve are closed to prevent the entry of external cold wind, thereby ensuring the internal temperature of the steel ash hopper and preventing the fallen ash from being hardened due to a relatively low temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of an industrial boiler flue ash blocking prevention system;

[0020] In the figure: 1. medium-pressure steam pipeline; 2. first valve; 3. flue; 4. compressed air pipeline; 5. compressed air valve; 6. high-temperature air chamber; 7. low-temperature air chamber; 8. vertical section; 9. high-pressure flushing water pipeline; 10. second valve; 11. steel ash hopper; 12. nozzle; 13. ash water pipeline; 14. ash water recovery tank; 15. fourth valve; 16. third valve; 17. horizontal section; 18. turning air chamber; 19. tubular air preheater; 20. heat exchange tube. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention.

[0022] Please refer to Figure 1 , an industrial boiler flue 3 anti-ash blocking system, comprising a flue 3 and a tubular air preheater 19 arranged in the flue 3, and also comprising:

[0023] A steam soot blowing pipe, which is used to blow away the soot attached to the heat exchange tube 20 of the tubular air preheater 19, the steam soot blowing pipe is connected to the medium-pressure steam pipeline 1, and is arranged in the flue 3 located at the upper part of the tubular air preheater 19;

[0024] A steel ash hopper 11 is connected between the vertical section 8 and the horizontal section 17 of the flue 3. The steel ash hopper 11 is in the shape of a cone barrel with upper and lower openings, and the upper opening of the steel ash hopper 11 faces the vertical section 8;

[0025] The nozzle 12 is used to flush the soot attached to the inner wall of the steel ash hopper 11. The nozzle 12 is arranged around the steel ash hopper 11 and is connected to the high-pressure flushing pipeline 9;

[0026] The ash water recovery pool 14 is connected to the lower opening of the steel ash hopper 11 through the ash water discharge pipeline 13.

[0027] Specifically, the tubular air preheater 19 used in this embodiment includes a high-temperature air chamber 6 connected to the air outlet of the upper heat exchange tube 20, a low-temperature air chamber 7 connected to the air inlet of the lower heat exchange tube 20, and a turning air chamber 18 connected to the air inlet of the upper heat exchange tube 20 and the air outlet of the lower heat exchange tube 20; the high-temperature air chamber 6 and the low-temperature air chamber 7 are located on the same side of the flue 3, and the turning air chamber 18 is located on the opposite side of the high-temperature air chamber 6.

[0028] Since the tubular preheater is generally arranged at the tail of the boiler, the flue gas temperature at this position is relatively low, and the flue gas contains a large amount of water vapor, which is easy to combine with the dust particles in the flue gas to form wet ash. When the flue gas passes through the tubular air preheater 19, the wet ash is easy to adhere to the heat exchange tube 20 of the tubular air preheater 19. After the flue gas continues to descend, after entering the conical steel ash hopper 11, a vortex is formed inside the conical upper opening of the steel ash hopper 11, and the smoke dust particles in the flue gas are disturbed and collided, and the flue gas flow loses energy, so that large dust particles and water droplets fall to the bottom of the steel ash hopper 11 along the smooth inner wall of the steel ash hopper 11 under the action of their own gravity and the downward thrust of the flue gas flow.

[0029] In order to avoid excessive ash accumulation on the heat exchange tube 20, during the operation of the boiler, the first valve 2 is opened regularly to transport steam to the steam soot blowing pipe (not shown in the figure) through the medium-pressure steam pipeline 1 to blow soot on the surface of the heat exchange tube 20 to clean the heat exchange tube 20, ensure the cleanliness of the surface of the heat exchange tube 20, ensure that the tubular air heat exchanger has a good heat exchange effect, improve the waste heat utilization rate of the flue gas, and thus reduce the heat loss of the exhaust gas. At the same time, most of the soot blown off the heat exchange tube 20 will fall into the steel ash hopper 11 with the flue gas flow. In order to facilitate the soot blowing of the heat exchange tube 20 at multiple angles and ensure the thoroughness of the soot blowing operation, the steam soot blowing pipe in this embodiment adopts a telescopic steam soot blowing pipe.

[0030] Compared with the traditional straight flue 3, the ash is accumulated at the connection between the vertical section 8 and the horizontal section 17, which easily causes the flue 3 to be blocked and the flue gas to flow poorly. In this embodiment, most of the ash falling from the vertical section 8 enters and gathers in the steel ash hopper 11, and does not occupy the original flue 3 space, so it does not affect the flow area of ​​the flue gas in the flue 3. Since most of the particles and dust in the flue gas fall into the steel ash hopper 11, the dust and particles in the flue gas entering the subsequent dust collector are relatively reduced, which also reduces the dust removal load of the dust collector to a certain extent.

[0031] When the smoke dust in the steel ash hopper 11 accumulates to a certain amount, the third valve 16 and the fourth valve 15 can be opened to discharge the smoke dust in the steel ash hopper 11 into the ash water recovery tank 14 through the ash water discharge pipeline 13 .

[0032] Inevitably, part of the soot accumulated in the steel ash hopper 11 may become hardened and stick to the bottom or inner wall of the steel ash hopper 11, causing poor ash discharge. At this time, it is necessary to open the second valve 10, and deliver high-pressure water to the nozzle 12 through the high-pressure flushing pipeline 9 to disperse the hardened soot to form ash water. Open the third valve 16 and the fourth valve 15, and discharge the soot to the ash water recovery pool 14 through the ash water discharge pipeline 13.

[0033] In order to ensure that the compacted fly ash can be effectively dispersed so that the dispersed fly ash can be smoothly discharged to the return water recovery pool through the ash discharge water pipeline 13, the nozzle 12 in this embodiment is facing the bottom of the steel ash hopper 11. At the same time, the water pressure in the high-pressure flushing water pipeline 9 should not be less than 1.2MPa to ensure that the high-pressure water sprayed by the nozzle 12 has sufficient impact force.

[0034] It should be noted that during the operation of the boiler, the third valve 16 and the fourth valve 15 are closed to prevent the entry of external cold air, to ensure the internal temperature of the steel ash hopper 11, and to prevent the fallen ash from becoming more easily hardened due to the relatively low temperature.

[0035] In one embodiment, in order to further facilitate the soot blowing operation on the surface of the heat exchange tube 20, a compressed air pipeline 4 is provided at the inlet of the flue 3 and located at the upper part of the tubular air preheater 19, and a compressed air valve 5 is provided on the compressed air pipeline 4.

[0036] Specifically, the telescopic steam soot blowing pipe can blow away most of the soot on the heat exchange tube 20, but inevitably, in some dead corners or with relatively strong adhesion, the soot will still adhere to the heat exchange tube 20. Therefore, during the maintenance period after the boiler stops running, the manholes at the inlet and outlet of the flue 3 of the tubular air preheater 19 are opened manually, and the flue 3 of the air preheater is manually entered, and the compressed air valve 5 is opened. The compressed air is used to thoroughly blow all corners of the tubular air preheater 19, and the blown ash will fall into the steel ash hopper 11 at the bottom of the flue 3. The ash accumulated in the steel ash hopper 11 is discharged into the ash water recovery pool through the ash discharge pipe.

[0037] The utility model arranges a conical steel ash hopper 11 between the vertical section 8 and the horizontal section 17 of the industrial boiler flue 3, so that the ash swept by the steam soot blowing pipe from the tubular heat exchanger slides down the inner wall of the slope of the conical steel ash hopper 11. At the same time, the flue gas forms a vortex after entering the conical steel ash hopper 11, and the smoke dust particles in the flue gas are disturbed and collided, resulting in energy loss of the flue gas flow, large particles of dust and water droplets fall into the steel ash hopper 11, and the high-pressure water sprayed by the nozzle 12 disperses the ash accumulated and hardened at the bottom of the steel ash hopper 11 and is discharged from the lower port to the return water recovery pool, so that the ash in the horizontal flue 3 at the lower port of the tubular air preheater 19 is easy to discharge and clean, thereby ensuring the smooth flow of the flue 3 at the tail end of the boiler, reducing the resistance of the flue gas in the flue 3, and making the tubular air preheater 19 effectively operate for a long period of time, while also reducing the dust removal load of the dust collector downstream of the flue gas.

[0038] The above is a specific implementation of the embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model. These improvements and modifications should also be regarded as the scope of protection of this application.

Claims

1. An industrial boiler flue ash blocking prevention system, comprising a flue (3) and a tubular air preheater (19) arranged in the flue (3), characterized in that: Also includes: a steam soot blowing pipe, used for blowing away soot attached to the heat exchange tube (20) of the tubular air preheater (19), the steam soot blowing pipe being connected to the medium-pressure steam pipeline (1) and arranged in the flue (3) located at the upper part of the tubular air preheater (19); A steel ash hopper (11) connected between the vertical section (8) and the horizontal section (17) of the flue (3), the steel ash hopper (11) being in the shape of a cone barrel with upper and lower openings, the upper opening of the steel ash hopper (11) facing the vertical section (8); A nozzle (12) is used to flush the hardened ash adhering to the inner wall of the steel ash hopper (11), the nozzle (12) is arranged on the peripheral side of the steel ash hopper (11), and the nozzle (12) is connected to the high-pressure flushing pipeline (9); The ash water recovery pool (14) is connected to the lower opening of the steel ash hopper (11) through an ash water discharge pipeline (13).

2. The industrial boiler flue ash blocking prevention system according to claim 1 is characterized in that: The tubular air preheater (19) comprises a high-temperature air chamber (6) connected to the air outlet of the upper heat exchange tube (20), a low-temperature air chamber (7) connected to the air inlet of the lower heat exchange tube (20), and a turning air chamber (18) connected to the air inlet of the upper heat exchange tube (20) and the air outlet of the lower heat exchange tube (20); the high-temperature air chamber (6) and the low-temperature air chamber (7) are located on the same side of the flue (3), and the turning air chamber (18) is located on the opposite side of the high-temperature air chamber (6).

3. The industrial boiler flue ash blocking prevention system according to claim 1 is characterized in that: The nozzle (12) is directed toward the bottom of the steel ash hopper (11).

4. The industrial boiler flue ash blocking prevention system according to claim 1 is characterized in that: A compressed air pipeline (4) is provided at the inlet of the flue (3) and located at the upper part of the tubular air preheater (19), and a compressed air valve (5) is provided on the compressed air pipeline (4).

5. The industrial boiler flue ash blocking prevention system according to claim 1 is characterized in that: The steam soot blowing pipe is telescopic.

6. The industrial boiler flue ash blocking prevention system according to claim 1 is characterized in that: The medium-pressure steam pipeline (1) and the high-pressure flushing water pipeline (9) are respectively provided with a first valve (2) and a second valve (10), and the ash water discharge pipeline (13) is respectively provided with a third valve (16) and a fourth valve (15) near the lower opening of the steel ash hopper (11) and near the inlet of the ash water recovery tank (14).

7. The industrial boiler flue ash blocking prevention system according to any one of claims 1 to 6, characterized in that: The pressure of the high-pressure flushing pipeline (9) is not less than 1.2 MPa.

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