阅读说明：本技术 防止屏式过热器超温的锅炉吹管方法 (Boiler blow pipe method for preventing overtemperature of platen superheater ) 是由 周福 田冠玉 张科 李冬 孙超 于 2021-05-25 设计创作，主要内容包括：本发明公开了一种防止屏式过热器超温的锅炉吹管方法,涉及火力发电技术领域,用于实施该防止屏式过热器超温的锅炉吹管方法的锅炉吹管系统包括水冷壁出口连接管、汽水分离器、WDC阀、各级过热器、临冲门；防止屏式过热器超温的锅炉吹管方法,包括以下步骤：步骤a,关闭WDC阀,将由水冷壁出口连接管进入汽水分离器的给水流量加大到能够实现蒸汽带水吹扫；步骤b,打开临冲门,蒸汽带水进行吹扫,吹扫过程中根据低温过热器、屏式过热器的温度加大或减小给水流量,以加大或减小蒸汽带水量；步骤c,吹扫结束后,关闭临冲门。本发明的优点在于：能够防止吹管时屏式过热器超温。(The invention discloses a boiler tube blowing method for preventing overtemperature of a platen superheater, which relates to the technical field of thermal power generation, and a boiler tube blowing system for implementing the boiler tube blowing method for preventing overtemperature of the platen superheater comprises a water wall outlet connecting tube, a steam-water separator, a WDC valve, each stage of superheater and a flushing door; the boiler blow pipe method for preventing overtemperature of the platen superheater comprises the following steps: step a, closing a WDC valve, and increasing the water supply flow entering a steam-water separator from a water wall outlet connecting pipe to a value capable of realizing steam-carried water purging; b, opening a flushing door, purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater and the platen superheater in the purging process to increase or decrease the water carrying amount of the steam; and c, closing the flushing door after purging is finished. The invention has the advantages that: and the overtemperature of the platen superheater during blowing pipe can be prevented.)

1. A boiler blowpipe method for preventing overtemperature of a platen superheater is characterized in that: the boiler blow pipe system for implementing the boiler blow pipe method for preventing the overtemperature of the platen superheater comprises a water wall outlet connecting pipe (1), a steam-water separator (2), a water storage tank (3), a drain pipeline (4), a WDC valve (5), a boiler drain flash tank (6), various stages of superheaters, a main steam pipeline (11), a flushing door (12), a particle collector (14), a high side pipe section (15) behind the high side valve, a cold secondary main pipe (16), various stages of reheaters (17), a hot secondary main pipe (18), a silencer (20) and a temporary pipeline; the water wall outlet connecting pipe (1) is connected with an inlet of the steam-water separator (2), a water outlet of the steam-water separator (2) is connected with a water inlet of the water storage tank (3) through a pipeline, a water outlet of the water storage tank (3) is connected with a water inlet of the boiler drainage flash tank (6) through the drainage pipeline (4), and the WDC valve (5) is arranged on the drainage pipeline (4); the steam outlet of the steam-water separator (2) is connected with the inlet header of each stage of superheater through a pipeline, each stage of superheater comprises a low-temperature superheater (8) and a platen superheater (9), and the outlet header of each stage of superheater is connected with the main steam pipeline (11); the main steam pipeline (11) is connected with the near flushing door (12) through a temporary pipeline, the near flushing door (12) is connected with the particle collector (14) through a temporary pipeline, and the particle collector (14) is connected with a rear high side pipe section (15) of the high side valve through a temporary pipeline; the high side pipe section (15) behind the high side valve is connected with the cold secondary main pipe (16), the cold secondary main pipe (16) is connected with the inlet header of each stage of reheater (17), and the outlet header of each stage of reheater (17) is connected with the hot secondary main pipe (18); the hot recycling main pipe (18) is connected with the silencer (20) through a temporary pipeline, and a steam outlet of the silencer (20) is communicated with the atmosphere;

the boiler tube blowing method for preventing the overtemperature of the platen superheater comprises a formal tube blowing step, and specifically comprises the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

and c, closing the flushing door (12) after the purging in the step b is finished.

2. The platen superheater overtemperature prevention boiler blowpipe method of claim 1, wherein: in the step a, the water supply flow entering the steam-water separator (2) from the water wall outlet connecting pipe (1) is increased to 600-800 t/h.

3. The platen superheater overtemperature prevention boiler blowpipe method of claim 1, wherein: formal blowing is carried out in a pressure reduction blowing mode;

in the step a, when the pressure of a steam outlet of the steam-water separator (2) rises to 6-7 MPa, closing the WDC valve (5);

and c, when the pressure of a steam outlet of the steam-water separator (2) is reduced to 4-5 MPa, finishing purging, and closing the flushing door (12).

4. The platen superheater overtemperature prevention boiler blowpipe method of claim 1, wherein: the official blowing pipe step further comprises the following steps:

and d, gradually reducing the water supply flow entering the steam-water separator (2) from the water wall outlet connecting pipe (1) to 350-450 t/h in the closing process of the flushing door (12) in the step c, and switching the WDC valve (5) into an automatic state after the flushing door (12) is completely closed to maintain the liquid level of the water storage tank (3) to be stable.

5. A boiler blow tube method for preventing platen superheater overtemperature as recited in any of claims 1-4 wherein: the boiler blow pipe method for preventing the overtemperature of the platen superheater comprises a first stage, a second stage and a third stage which are sequentially carried out;

the first stage comprises the following steps:

step A, feeding water into a boiler, and flushing in a cold state;

b, after the step A is finished, igniting the boiler and flushing in a thermal state;

step C, after the step B is finished, trial blowing the pipe;

and D, after the step C is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

e, stopping the furnace and cooling after the step D is finished; checking and cleaning the collector (14) during the furnace shutdown;

the second stage comprises the following steps:

f, feeding water into the boiler, and flushing in a cold state;

g, after the step F is finished, igniting the boiler and flushing in a hot state;

step H, after the step G is finished, trial blowing the pipe;

step I, after the step H is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

step J, after the step I is finished, stopping the furnace and cooling; checking and cleaning the collector (14) during the furnace shutdown;

the third stage comprises the following steps:

f, feeding water into the boiler, and flushing in a cold state;

g, after the step F is finished, igniting the boiler and flushing in a hot state;

step H, after the step G is finished, trial blowing the pipe;

step I, after the step H is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

the steps F to I of the third stage are the same as the specific steps F to I of the second stage;

step K, after the step I is finished, the target shooting of the superheater and the reheater specifically comprises the following steps:

continuously purging, namely adding a superheater target plate (13) on a temporary pipeline between a temporary flushing door (12) and a particle collector (14) after the steam cleanliness at the steam outlet of the silencer (20) is qualified by visual inspection; when the superheater target plate (13) is qualified after the target hitting for the specified times continuously, a reheater target plate (19) is additionally arranged on a temporary pipeline between a hot header pipe (18) and a silencer (20); and continuously purging until the target of the reheater target plate (19) is qualified after being continuously targeted for a specified number of times, ending the blowing pipe, and stopping the furnace for maintenance.

6. The platen superheater overtemperature prevention boiler blowpipe method of claim 5, wherein: in the first stage:

in the step A, the pipelines at the water reducing side of the superheater and the reheater are flushed simultaneously in the cold flushing process;

in the step C, the superheater and the reheater are subjected to temperature reduction water vapor side pipeline purging simultaneously in the process of the trial blowing pipe;

in the step E, recovering the superheater temperature reduction water pipeline, the reheater temperature reduction water pipeline, the regulating valve and the flowmeter during the furnace shutdown, and debugging and driving the temperature reduction water regulating valve to ensure that the superheater temperature reduction water pipeline, the reheater temperature reduction water pipeline, the regulating valve and the flowmeter can be normally put into use;

the step I of the second stage and the third stage also comprises the following steps:

step e, in the purging process of the step b, intercepting the manual door at the temperature reduction water inlet, and putting primary and secondary temperature reduction water of the superheater;

and f, closing the primary and secondary desuperheating water of the superheater in the closing process of the temporary flushing door (12) in the step c.

7. The platen superheater overtemperature prevention boiler blowpipe method of claim 5, wherein: and in the step K, before the superheater target plate (13) is additionally arranged, the drainage of the boiler drainage flash tank (6) is discharged from a unit drainage groove.

8. The platen superheater overtemperature prevention boiler blowpipe method of claim 5, wherein: in the step A of the first stage and the step F of the second stage and the third stage, the cold state flushing is firstly carried out by adopting a whole furnace water changing mode, and when the furnace water Fe is less than 500 mug/L, the mode is changed into open type variable flow rate flushing until the cold state flushing is qualified.

9. The platen superheater overtemperature prevention boiler blowpipe method of claim 5, wherein: in the step B of the first stage and the step G of the second stage and the third stage, the thermal state flushing firstly adopts open variable flow flushing, when the Fe of the furnace water is less than 500 mug/L, the furnace water is put into a pre-filter of the fine processing system and is switched into closed circulation flushing, the furnace water is switched into open variable flow flushing after a certain time, and then the open variable flow flushing and the closed circulation flushing are repeatedly and alternately carried out according to the set time until the thermal state flushing is qualified.

10. The platen superheater overtemperature prevention boiler blowpipe method of claim 5, wherein: in the step C of the first stage and the step H of the second stage and the third stage, trial blowing pipes are carried out in a pressure reduction blowing pipe mode, and trial blowing pipes with the steam outlet pressure of the steam-water separator (2) being 2MPa, 3.5MPa and 5MPa are respectively carried out.

Technical Field

The invention relates to the technical field of thermal power generation, in particular to a boiler blowpipe method for preventing overtemperature of a platen superheater.

Background

With the high development of national industry, the demand of electric power is getting larger and higher, and therefore, the thermal power plant plays an increasingly important role in the process of the high development of national economy. As one of the most important equipments in the thermal power plant, the generation of the boiler and its accessories is also getting faster and faster. The ultra-supercritical once-through boiler with high parameter and large capacity has the economic advantages of high power generation and low coal consumption, and becomes the most popular boiler type which is developed most rapidly in recent years.

The newly installed unit has sand grains, iron scale, iron filings, welding slag and chemical cleaning matter left in the superheater, reheater and steam pipeline in different degrees for manufacture, installation, storage, transportation and other reasons, and the said impurities can be removed by boiler blow pipe to avoid blocking, pipe explosion and high-temperature corrosion of heated surface pipe caused by these matters in heated surface after unit is put into service, or brought into turbine to endanger the safe operation of turbine generator unit.

At present, various methods for debugging a blowing pipe are mature, but no proper solution is provided for the problem of overtemperature of a platen superheater during certain furnace type blowing pipes, for example, patent CN105352361A discloses a method for blowing a steam pipe for an ultra-supercritical once-through boiler without a water pump, which comprises a first stage: purging by a trial-blow pipe, a reheater and a superheater desuperheating water pipeline and a high-pressure bypass pipeline; and a second stage: the boiler pass, reheater and connecting pipeline are connected in series for pressure-stabilizing blowing; and a third stage: the boiler superheater, the reheater and the connecting pipeline are connected in series for stable pressure reduction and purging; and (4) stopping the boiler for maintenance after the target shooting is qualified, and finishing the operation of blowing pipes. Because some furnace types are under low load, particularly in a blowing pipe stage, a low-temperature superheater and a platen superheater absorb too much heat, and the tube panel of the platen superheater is easy to overtemperature, and the existing blowing pipe debugging method has no better solution to the problem.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a boiler blow pipe method for preventing the overtemperature of a platen superheater, which can prevent the overtemperature of the platen superheater during blow pipe.

The invention solves the technical problems through the following technical means: the boiler blow pipe system for implementing the boiler blow pipe method for preventing the overtemperature of the platen superheater comprises a water wall outlet connecting pipe (1), a steam-water separator (2), a water storage tank (3), a drain pipeline (4), a WDC valve (5), a boiler drain flash tank (6), various stages of superheaters, a main steam pipeline (11), a flushing door (12), a particle collector (14), a high side pipe section (15) behind the high side valve, a cold secondary main pipe (16), various stages of reheaters (17), a hot secondary main pipe (18), a silencer (20) and a temporary pipeline; the water wall outlet connecting pipe (1) is connected with an inlet of the steam-water separator (2), a water outlet of the steam-water separator (2) is connected with a water inlet of the water storage tank (3) through a pipeline, a water outlet of the water storage tank (3) is connected with a water inlet of the boiler drainage flash tank (6) through the drainage pipeline (4), and the WDC valve (5) is arranged on the drainage pipeline (4); the steam outlet of the steam-water separator (2) is connected with the inlet header of each stage of superheater through a pipeline, each stage of superheater comprises a ceiling superheater (7), a low-temperature superheater (8), a platen superheater (9) and a high-temperature superheater (10) which are sequentially connected through pipelines, and the outlet header of each stage of superheater is connected with the main steam pipeline (11); the main steam pipeline (11) is connected with the near flushing door (12) through a temporary pipeline, the near flushing door (12) is connected with the particle collector (14) through a temporary pipeline, and the particle collector (14) is connected with a rear high side pipe section (15) of the high side valve through a temporary pipeline; the high side pipe section (15) behind the high side valve is connected with the cold secondary main pipe (16), the cold secondary main pipe (16) is connected with the inlet header of each stage of reheater (17), and the outlet header of each stage of reheater (17) is connected with the hot secondary main pipe (18); the hot recycling main pipe (18) is connected with the silencer (20) through a temporary pipeline, and a steam outlet of the silencer (20) is communicated with the atmosphere;

the boiler tube blowing method for preventing the overtemperature of the platen superheater comprises a formal tube blowing step, and specifically comprises the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

and c, closing the flushing door (12) after the purging in the step b is finished.

The steam with water is blown and swept, the steam temperature of the platen superheater can be controlled, the overtemperature of the tube wall of the platen superheater is prevented, the temperature of the steam at the outlet of the high-temperature superheater is ensured to be less than or equal to 450 ℃, and the safety and the reliability of the system are ensured.

In the step a, the flow of feed water entering the steam-water separator (2) from the water wall outlet connecting pipe (1) is increased to 600-800 t/h.

As an optimized technical scheme, a pressure reduction blowing pipe mode is adopted for formal blowing pipe;

in the step a, when the pressure of a steam outlet of the steam-water separator (2) rises to 6-7 MPa, closing the WDC valve (5);

and c, when the pressure of a steam outlet of the steam-water separator (2) is reduced to 4-5 MPa, finishing purging, and closing the flushing door (12).

As an optimized technical scheme, the formal blowpipe step further comprises the following steps:

and d, gradually reducing the water supply flow entering the steam-water separator (2) from the water wall outlet connecting pipe (1) to 350-450 t/h in the closing process of the flushing door (12) in the step c, and switching the WDC valve (5) into an automatic state after the flushing door (12) is completely closed to maintain the liquid level of the water storage tank (3) to be stable.

As an optimized technical scheme, the boiler tube blowing method for preventing the overtemperature of the platen superheater comprises a first stage, a second stage and a third stage which are sequentially carried out;

the first stage comprises the following steps:

step A, feeding water into a boiler, and flushing in a cold state;

b, after the step A is finished, igniting the boiler and flushing in a thermal state;

step C, after the step B is finished, trial blowing the pipe;

and D, after the step C is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

e, stopping the furnace and cooling after the step D is finished; checking and cleaning the collector (14) during the furnace shutdown;

the second stage comprises the following steps:

f, feeding water into the boiler, and flushing in a cold state;

g, after the step F is finished, igniting the boiler and flushing in a hot state;

step H, after the step G is finished, trial blowing the pipe;

step I, after the step H is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

step J, after the step I is finished, stopping the furnace and cooling; checking and cleaning the collector (14) during the furnace shutdown;

the third stage comprises the following steps:

f, feeding water into the boiler, and flushing in a cold state;

g, after the step F is finished, igniting the boiler and flushing in a hot state;

step H, after the step G is finished, trial blowing the pipe;

step I, after the step H is finished, formally blowing a pipe, and specifically comprising the following steps:

step a, closing a WDC valve (5), and increasing the water supply flow entering a steam-water separator (2) from a water wall outlet connecting pipe (1) to a value capable of realizing steam with water purging;

step b, after the step a is finished, opening a flushing door (12), purging with water by steam, and increasing or decreasing the water supply flow according to the temperatures of the low-temperature superheater (8) and the platen superheater (9) in the purging process to increase or decrease the water carrying amount of the steam;

step c, after the purging in the step b is finished, closing the flushing door (12);

the steps F to I of the third stage are the same as the specific steps F to I of the second stage;

step K, after the step I is finished, the target shooting of the superheater and the reheater specifically comprises the following steps:

continuously purging, namely adding a superheater target plate (13) on a temporary pipeline between a temporary flushing door (12) and a particle collector (14) after the steam cleanliness at the steam outlet of the silencer (20) is qualified by visual inspection; when the superheater target plate (13) is qualified after the target hitting for the specified times continuously, a reheater target plate (19) is additionally arranged on a temporary pipeline between a hot header pipe (18) and a silencer (20); and continuously purging until the target of the reheater target plate (19) is qualified after being continuously targeted for a specified number of times, ending the blowing pipe, and stopping the furnace for maintenance.

As an optimized technical scheme, in the first stage:

in the step A, the pipelines at the water reducing side of the superheater and the reheater are flushed simultaneously in the cold flushing process;

in the step C, the superheater and the reheater are subjected to temperature reduction water vapor side pipeline purging simultaneously in the process of the trial blowing pipe;

in the step E, recovering the superheater temperature reduction water pipeline, the reheater temperature reduction water pipeline, the regulating valve and the flowmeter during the furnace shutdown, and debugging and driving the temperature reduction water regulating valve to ensure that the superheater temperature reduction water pipeline, the reheater temperature reduction water pipeline, the regulating valve and the flowmeter can be normally put into use;

the step I of the second stage and the third stage also comprises the following steps:

step e, in the purging process of the step b, intercepting the manual door at the temperature reduction water inlet, and putting primary and secondary temperature reduction water of the superheater;

and f, closing the primary and secondary desuperheating water of the superheater in the closing process of the temporary flushing door (12) in the step c.

The mode that sweeps and put into use superheater desuperheating water through steam area water combines together prevents that screen superheater pipe wall overtemperature and ensures that the effect that high temperature superheater export steam temperature is suitable is better, has further ensured the safe and reliable of system.

And as an optimized technical scheme, in the step K, before the superheater target plate (13) is additionally arranged, the drainage of the boiler drainage flash tank (6) is discharged from a unit drainage tank. Before installing the over heater target plate additional, the drainage of the hydrophobic flash tank of boiler no longer retrieves, can improve stove water, steam quality for the qualified process of target plate, shorten the blowpipe consuming time, play energy saving and consumption reduction's effect.

As an optimized technical scheme, in the step A of the first stage and the step F of the second and third stages, cold state flushing is firstly performed by adopting a whole furnace water changing mode, and when the furnace water Fe is less than 500 mug/L, the mode is switched to open type variable flow rate flushing until the cold state flushing is qualified.

As an optimized technical scheme, in the step B of the first stage and the step G of the second stage and the third stage, the thermal state flushing firstly adopts open variable flow flushing, when the Fe of furnace water is less than 500 mug/L, a pre-filter of a fine processing system is put into the thermal state flushing, the closed circulation flushing is changed into the closed circulation flushing, the open variable flow flushing is changed into the open variable flow flushing after a certain time, and then the open variable flow flushing and the closed circulation flushing are repeatedly and alternately carried out according to the set time until the thermal state flushing is qualified.

As an optimized technical scheme, in the step C of the first stage and the step H of the second stage and the third stage, a pressure reduction blowing pipe mode is adopted for trial blowing pipes, and trial blowing pipes with the steam outlet pressure of the steam-water separator (2) being 2MPa, 3.5MPa and 5MPa are respectively carried out.

The invention has the advantages that:

1. the steam temperature of the platen superheater can be controlled, the overtemperature of the tube wall of the platen superheater is prevented, the temperature of the steam at the outlet of the high-temperature superheater is ensured to be less than or equal to 450 ℃, the safety and the reliability of the system are ensured, the principle is simple, and the operation is easy.

2. The steam with water is swept and combined with the primary desuperheating water and the secondary desuperheating water of the superheater, so that the effect of preventing the pipe wall of the platen superheater from overtemperature and ensuring the outlet steam temperature of the high-temperature superheater to be proper is better.

3. Before installing the over heater target plate additional, the drainage of the hydrophobic flash tank of boiler no longer retrieves, can improve stove water, steam quality for the qualified process of target plate, shorten the blowpipe consuming time, play energy saving and consumption reduction's effect.

Drawings

Fig. 1 is a schematic structural view of a boiler blowpipe system according to an embodiment of the present invention.

FIG. 2 is a flow chart of a first stage of a boiler blow tube method of preventing platen superheater overtemperature in accordance with an embodiment of the present invention.

FIG. 3 is a flow chart of a second stage of a boiler blow tube method of preventing platen superheater overtemperature in accordance with an embodiment of the present invention.

FIG. 4 is a flow chart of a third stage of a boiler blow tube method of preventing platen superheater overtemperature in accordance with an embodiment of the present invention.

Fig. 5 is a flow chart of the steps of a pilot torch in accordance with an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in FIG. 1, the boiler blow pipe system comprises a water wall outlet connecting pipe 1, a steam-water separator 2, a water storage tank 3, a drain pipeline 4, a WDC valve 5, a boiler drain flash tank 6, each stage of superheaters, a main steam pipeline 11, a flush door 12, a superheater target plate 13, a grain collector 14, a high-side valve rear high-side pipeline section 15, a cold-reheater mother pipe 16, each stage of reheater 17, a hot-reheater mother pipe 18, a reheater target plate 19, a silencer 20, a water drain device 21 and temporary pipelines, wherein thick dotted lines represent temporary pipelines.

The water wall outlet connecting pipe 1 is connected with an inlet of a steam-water separator 2, a water outlet of the steam-water separator 2 is connected with a water inlet of a water storage tank 3 through a pipeline, a water outlet of the water storage tank 3 is connected with a water inlet of a boiler drainage flash tank 6 through a drainage pipeline 4, and a WDC valve 5 is arranged on the drainage pipeline 4; the steam outlet of the steam-water separator 2 is connected with the inlet header of each stage of superheater through a pipeline, each stage of superheater comprises a ceiling superheater 7, a low-temperature superheater 8, a screen type superheater 9 and a high-temperature superheater 10 which are sequentially connected through pipelines, and the outlet header of the high-temperature superheater 10 is connected with a main steam pipeline 11; the main steam pipeline 11 is connected with a near-impact door 12 through a temporary pipeline, the near-impact door 12 is connected with a particle collector 14 through a temporary pipeline, a superheater target plate 13 is additionally arranged on the temporary pipeline between the near-impact door 12 and the particle collector 14 during the target hitting of the superheater, and the particle collector 14 is connected with a high side pipe section 15 behind the high side valve through a temporary pipeline; a high side pipe section 15 behind the high side valve is connected with a cold secondary main pipe 16, the cold secondary main pipe 16 is connected with an inlet header of each stage of reheater 17, and an outlet header of each stage of reheater 17 is connected with a hot secondary main pipe 18; the hot recollecting main pipe 18 is connected with a silencer 20 through a temporary pipeline, a reheater target plate 19 is additionally arranged on the temporary pipeline between the hot recollecting main pipe 18 and the silencer 20 during the target shooting of the reheater, and a steam outlet of the silencer 20 is communicated with the atmosphere; the water drainage device 21 is connected with a temporary pipeline between the reheater target plate 19 and the silencer 20 through a temporary pipeline, and drainage of the temporary pipeline is discharged through the water drainage device 21; and (3) dismantling the high side valve, disconnecting the high side pipeline from the original high side valve position 22, blocking the high side pipeline section in front of the high side valve, and manually cleaning after the blow pipe is finished.

The superheater, the reheater and the connecting pipeline of the boiler are serially purged through a boiler blowing pipe system, and the steam flow is as follows: steam-water separator 2 → ceiling superheater 7 → low-temperature superheater 8 → platen superheater 9 → high-temperature superheater 10 → main steam piping 11 → temporary piping → approach door 12 → temporary piping → superheater target plate 13 → temporary piping → grain collector 14 → temporary piping → high-side valve rear high-side pipe section 15 → cold reheat header pipe 16 → each stage reheater 17 → hot reheat header pipe 18 → temporary piping target plate 19 → temporary piping → muffler 20 → atmosphere.

The boiler blow pipe method for preventing overtemperature of the platen superheater comprises a first stage, a second stage and a third stage which are sequentially carried out

As shown in fig. 2, the first stage comprises the following steps:

step A, feeding water into a boiler, flushing in a cold state, and flushing a superheater and a reheater temperature reduction water side pipeline simultaneously in the cold state flushing process, wherein the method specifically comprises the following steps:

in the cold state flushing process, the water is added with chemicals, in order to save water, the cold state flushing is firstly flushed by adopting a whole furnace water changing mode, when the Fe of the furnace water is less than 500 mug/L, the furnace water is switched into open variable flow flushing, the water supply flow of the open variable flow flushing is 10% -25% BMCR, and the cold state flushing is qualified.

The flow of flushing water of the superheater desuperheating water side pipeline is as follows: water supply pipeline → superheater attemperation water pipeline → electric door before attemperation water control valve at each level of superheater → temporary pipeline → discharge port, superheater attemperation water control valve is not installed temporarily, and temporary pipeline is connected to discharge washing water from discharge port to safe place.

The flushing water flow of the reheater desuperheating water side pipeline is as follows: the middle tap of the water feeding pump → the reheater desuperheating water pipeline → the electric door in front of the reheater desuperheating water regulating valve → a temporary pipeline → a discharge port, the reheater desuperheating water regulating valve is temporarily not installed, and the temporary pipeline is connected to discharge the flushing water to a safe place from the discharge port.

Step B, after the step A is finished, igniting the boiler and flushing in a thermal state, and specifically comprises the following steps:

controlling the water temperature of a water outlet of the steam-water separator 3 to be about 190 ℃ in the hot state washing process, firstly adopting open variable flow washing in the hot state washing, when the Fe of furnace water is less than 500 mug/L, putting the furnace water into a pre-filter of a fine treatment system, turning the furnace water into closed circulation washing, turning the furnace water into open variable flow washing after one hour, and then repeatedly and alternately washing for half an hour according to the open variable flow washing and one hour according to the closed circulation washing until the hot state washing is qualified.

Step C, after the step B is finished, blowing a test tube, and blowing the desuperheating water vapor side pipeline of the superheater and the reheater simultaneously in the process of blowing the test tube, wherein the method specifically comprises the following steps:

and (3) raising the temperature and boosting the pressure of the boiler, performing trial blowing pipes in a pressure reduction blowing pipe mode, performing trial blowing pipes under the steam outlet pressures of the steam-water separator 2 of 2MPa, 3.5MPa and 5MPa respectively, and repeating the trial blowing pipes until the temperature-reduction steam-water side pipeline is qualified in blowing.

The steam flow for purging the superheater temperature reduction water vapor side pipeline comprises the following steps: superheater desuperheater → superheater desuperheater pipeline → electric door behind the desuperheater water regulating valves of the superheater → temporary pipeline → discharge port, the superheater desuperheater water regulating valve is not installed temporarily, and the temporary pipeline is connected to discharge steam from the discharge port to a safe place.

The flushing process of the reheater temperature reduction water vapor side pipeline comprises the following steps: reheater desuperheater → reheater desuperheating water pipeline → electric door behind reheater desuperheating water regulating valve → temporary pipeline → discharge outlet, reheater desuperheating water regulating valve is not installed temporarily, and temporary pipeline is connected to discharge steam from the discharge outlet to the safe place.

Step D, after the step C is finished, the pressure of the boiler is continuously increased, and formal pipe blowing is carried out in a pressure reduction pipe blowing mode, as shown in fig. 5, the method specifically comprises the following steps:

step a, when the pressure of a steam outlet of the steam-water separator 2 is increased to 6-7 MPa, manually closing a WDC valve 5, increasing the water supply flow entering the steam-water separator 2 from a water wall outlet connecting pipe 1 to 650t/h from 350-450 t/h, wherein the water supply flow can realize steam purging with water, and the liquid level of a water storage tank 3 is increased to 13-14 m from about 7 m.

Step b, after the step a is finished, opening the adjacent flushing door 12, wherein the distance from the full opening of the adjacent flushing door 12 to the full closing of the adjacent flushing door 12 is 39s, the steam obviously circulates after the adjacent flushing door 12 is opened for 3-5 s, the steam carries water for purging, and the water supply flow is increased or decreased according to the temperatures of the low-temperature superheater 8 and the platen superheater 9 in the purging process so as to increase or decrease the water carrying capacity of the steam; and (3) adjusting the parameters of the blowing pipe, and ensuring that the blowing pipe coefficient is more than or equal to 1.4 in terms of pressure drop ratio.

And c, in the step b, when the pressure of the steam outlet of the steam-water separator 2 is reduced to 4-5 MPa, finishing purging, and closing the flushing door 12.

And d, gradually reducing the water supply flow entering the steam-water separator 2 from the water wall outlet connecting pipe 1 to 350-450 t/h in the closing process of the flushing door 12 in the step c, and switching the WDC valve 5 into an automatic state after the flushing door 12 is completely closed to maintain the liquid level of the water storage tank 3 stable and take away the combustion heat of the pulverized coal through water circulation.

Blowing pipes from step a to step d for 1 time, blowing pipes for 4 times per hour, and blowing pipes for 10-20 times, so that the steam cleaning condition at the steam outlet of the silencer 20 is obviously improved.

And E, stopping the furnace and cooling after the step D is finished, and specifically comprising the following steps: blowing out the furnace and cooling for at least 12 hours; the collector 14 is checked and cleaned during the furnace shutdown; and recovering the superheater desuperheating water pipeline and the reheater desuperheating water pipeline, the regulating valve and the flowmeter during the furnace shutdown, and debugging and driving the desuperheating water regulating valve to ensure that the reheater desuperheating water regulating valve can be normally put into use.

As shown in fig. 3, the second stage includes the following steps:

step F, feeding water to the boiler, and flushing in a cold state, wherein the method specifically comprises the following steps:

in the cold state flushing process, the water is added with chemicals, in order to save water, the cold state flushing is firstly flushed by adopting a whole furnace water changing mode, when the Fe of the furnace water is less than 500 mug/L, the furnace water is switched into open variable flow flushing, the water supply flow of the open variable flow flushing is 10% -25% BMCR, and the cold state flushing is qualified.

G, after the step F is finished, igniting the boiler and carrying out hot state washing, and specifically comprises the following steps:

controlling the water temperature of a water outlet of the steam-water separator 3 to be about 190 ℃ in the hot state washing process, firstly adopting open variable flow washing in the hot state washing, when the Fe of furnace water is less than 500 mug/L, putting the furnace water into a pre-filter of a fine treatment system, turning the furnace water into closed circulation washing, turning the furnace water into open variable flow washing after one hour, and then repeatedly and alternately washing for half an hour according to the open variable flow washing and one hour according to the closed circulation washing until the hot state washing is qualified.

Step H, after the step G is completed, trial blowing the pipe, specifically comprising the following steps:

and raising the temperature and the pressure of the boiler, performing trial blowing pipes by adopting a pressure reduction blowing pipe mode, and performing trial blowing pipes under the steam outlet pressures of the steam-water separator 2 of 2MPa, 3.5MPa and 5MPa respectively.

Step I, after the step H is finished, the pressure of the boiler is continuously increased, and a positive test blowpipe is carried out in a pressure reduction blowpipe mode, as shown in FIG. 5, the method specifically comprises the following steps:

step a, when the pressure of a steam outlet of the steam-water separator 2 is increased to 6-7 MPa, manually closing a WDC valve 5, increasing the water supply flow entering the steam-water separator 2 from a water wall outlet connecting pipe 1 to 650t/h from 350-450 t/h, wherein the water supply flow can realize steam purging with water, and the liquid level of a water storage tank 3 is increased to 13-14 m from about 7 m.

Step b, after the step a is finished, opening the adjacent flushing door 12, wherein the distance from the full opening of the adjacent flushing door 12 to the full closing of the adjacent flushing door 12 is 39s, the steam obviously circulates after the adjacent flushing door 12 is opened for 3-5 s, the steam carries water for purging, and the water supply flow is increased or decreased according to the temperatures of the low-temperature superheater 8 and the platen superheater 9 in the purging process so as to increase or decrease the water carrying capacity of the steam; and (3) adjusting the parameters of the blowing pipe, and ensuring that the blowing pipe coefficient is more than or equal to 1.4 in terms of pressure drop ratio.

Step e, in the purging process of the step b, intercepting a manual door at a desuperheating water inlet, and adding a small amount of desuperheating water of the primary level and the secondary level of the superheater to ensure that the regulating valve has a certain regulating room, and ensuring that the temperature after the desuperheater of the superheater has the superheat degree of more than 30 ℃ in the adding process; the mode of combining the steam with water for purging and the primary and secondary desuperheating water of the superheater is adopted, the steam temperature of the platen superheater 9 and the high-temperature superheater 10 is controlled, the pipe wall of the platen superheater 9 is prevented from being over-heated, the outlet steam temperature of the high-temperature superheater 10 is ensured to be less than or equal to 450 ℃, and the safety and reliability of the temporary pipeline of the boiler blow pipe system are ensured.

And c, in the step b, when the pressure of the steam outlet of the steam-water separator 2 is reduced to 4-5 MPa, finishing purging, and closing the flushing door 12.

And f, closing the primary and secondary desuperheating water of the superheater in the closing process of the temporary flushing door 12 in the step c.

And d, gradually reducing the water supply flow entering the steam-water separator 2 from the water wall outlet connecting pipe 1 to 350-450 t/h in the closing process of the flushing door 12 in the step c, and switching the WDC valve 5 into an automatic state after the flushing door 12 is completely closed to maintain the liquid level of the water storage tank 3 to be stable.

Blowing pipes from step a to step d for 1 time, blowing pipes for 4 times per hour, and blowing pipes for 10-20 times, so that the steam cleaning condition at the steam outlet of the silencer 20 is obviously improved.

Step J, after the step I is finished, stopping the furnace and cooling, and specifically comprises the following steps: blowing out the furnace and cooling for at least 12 hours; the collector 14 is inspected and cleaned during the furnace shutdown.

As shown in fig. 4, the third stage includes the following steps:

and F, feeding water to the boiler, and flushing in a cold state.

G, after the step F is finished, igniting the boiler and flushing in a hot state.

And step H, after the step G is finished, trial blowing the pipe.

And step I, after the step H is finished, the boiler continues to be boosted, and a positive trial blowing pipe is carried out in a pressure reduction blowing pipe mode.

The steps F to I of the third stage are the same as the specific steps F to I of the second stage.

Step K, after the step I is finished, the target shooting of the superheater and the reheater specifically comprises the following steps:

continuously purging, namely adding a superheater target plate 13 on a temporary pipeline between the temporary flushing door 12 and the particle collector 14 after the steam cleanliness at the steam outlet of the silencer 20 is qualified by visual inspection; before the superheater target plate 13 is additionally arranged, the drainage of the boiler drainage flash tank 6 is discharged from a unit drainage tank; when the superheater target plate 13 is qualified after two successive times of target shooting, the reheater target plate 19 is additionally arranged on a temporary pipeline between the hot header 18 and the silencer 20; and continuously purging until the target plate 19 of the reheater is qualified after two times of continuous target shooting, ending the blowing pipe, and stopping the furnace for maintenance.

Example two

The difference between the embodiment and the first embodiment is that in the step d, the water supply flow entering the steam-water separator 2 from the water wall outlet connecting pipe 1 is increased to 600t/h from 350-450 t/h, the water supply flow can realize steam purging with water, and the liquid level of the water storage tank 3 is increased to 12-13 m from about 7 m.

EXAMPLE III

The difference between the embodiment and the first embodiment is that in the step d, the water supply flow entering the steam-water separator 2 from the water wall outlet connecting pipe 1 is increased to 800t/h from 350-450 t/h, the water supply flow can realize steam purging with water, and the liquid level of the water storage tank 3 is increased to 15-16 m from about 7 m.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.