CN218542336U - Coal fired power plant starting process flue gas auxiliary heating system - Google Patents

Abstract

The utility model discloses a coal fired power plant starting process flue gas auxiliary heating system, include: the first heat exchange piece is communicated with the flue gas outlet through a first pipeline, a first passage is arranged in the first heat exchange piece, an inlet of the first passage is communicated with the outside through a second pipeline, an outlet of the first passage is communicated with the second heat exchange piece through a third pipeline, and the air feeder is arranged on the second pipeline; the low-pressure cylinder is communicated with the steam outlet through a fourth pipeline, and part of the fourth pipeline is arranged in the second heat exchange piece. In the unit start-up process, in the flue gas input first heating member that the boiler produced, the forced draught blower extracts in the external air sends into first passageway through the second pipeline, because first passageway is located first heat exchange piece, thereby make the air through first passageway promote the temperature, promote the air of temperature and pass through in third pipeline input second heat exchange piece, the air of promotion temperature makes the temperature rise in the second heat exchange piece, during steam gets into the fourth pipeline that is located the second heat exchange piece, make this steam heat-up.

Description

Coal fired power plant starting process flue gas auxiliary heating system

Technical Field

The utility model relates to a coal fired power plant's technical field, concretely relates to coal fired power plant starting process flue gas auxiliary heating system.

Background

With the development of renewable energy sources, the proportion of renewable energy sources for power generation is increasing, but due to the intermittent and unpredictable characteristics of renewable energy sources, the peak shaving task of coal-fired power plants is also increasing in order to maintain the stability of a power grid.

The existing effective method for peak shaving of the coal-fired power plant reduces electric energy generated by burning part of fuel by shutting down part of units, restarts the part of units within 24 hours, increases electric energy generated by burning the fuel, and realizes the peak shaving requirement of the coal-fired power plant by starting and stopping the part of units.

However, in the peak shaving method for the coal-fired power plant, the turbine rotor and the shell need to be preheated in the starting process of the unit, and the preheating process of the turbine rotor and the shell takes more time and consumes a large amount of energy due to the fact that the turbine rotor and the shell are large in mass, so that the starting cost and the energy consumption of the coal-fired power plant are increased.

SUMMERY OF THE UTILITY MODEL

Therefore, the utility model aims to solve the technical problem that the unit needs preheat steam turbine rotor and casing in the starting process among the prior art, because the quality of steam turbine rotor and casing is great, its preheating process can occupy more time to consume a large amount of energy, thereby increased coal fired power plant's start-up cost and energy consumption.

Therefore, the utility model provides a coal fired power plant starting process flue gas auxiliary heating system, a serial communication port, include:

a boiler having a flue gas outlet and a steam outlet;

the heat exchange system comprises a first heat exchange piece, a second heat exchange piece and a blower, the first heat exchange piece is suitable for being communicated with the smoke outlet through a first pipeline, a first passage is arranged in the first heat exchange piece, an inlet of the first passage is communicated with the outside through a second pipeline, an outlet of the first passage is communicated with the second heat exchange piece through a third pipeline, and the blower is arranged on the second pipeline;

and the steam turbine set comprises a low-pressure cylinder, the low-pressure cylinder is suitable for being communicated with the steam outlet through a fourth pipeline, and part of the fourth pipeline is arranged in the second heat exchange piece.

Optionally, foretell coal fired power plant starting process flue gas auxiliary heating system, the steam turbine unit still includes high-pressure cylinder and intermediate pressure jar, the fourth pipeline divide into first subsection pipe, second subsection pipe and third subsection pipe, the high-pressure cylinder through first subsection pipe with steam outlet intercommunication, second subsection pipe one end with high-pressure cylinder intercommunication, the second subsection pipe other end with intermediate pressure jar intercommunication, third subsection pipe one end with intermediate pressure jar intercommunication, the third subsection pipe other end with low-pressure cylinder intercommunication, and part the third subsection pipe sets up in the second heat transfer piece.

Optionally, in the above-mentioned coal fired power plant starting process flue gas auxiliary heating system, the steam turbine unit further includes a first switch, and the first switch is arranged on the first section pipe and is used for controlling the on-off between the steam outlet and the high pressure cylinder.

Optionally, in the above-mentioned coal fired power plant starting process flue gas auxiliary heating system, the heat exchange system further includes a second switch, and the second switch is arranged on the third pipeline and is used for controlling the on-off between the first passage and the second heat exchange.

Optionally, foretell coal fired power plant starting process flue gas auxiliary heating system, heat transfer system still includes air heater, first pipeline divide into fourth subsection pipe and fifth subsection pipe, fourth subsection pipe one end with the exhanst gas outlet intercommunication, the fourth subsection pipe other end with air heater intercommunication, fifth subsection pipe one end with air heater intercommunication, the fifth subsection pipe other end with first heat transfer piece intercommunication.

Optionally, foretell coal fired power plant start-up process flue gas auxiliary heating system, heat exchange system still includes third heat transfer spare, set up the second route in the air heater, the import of second route with the export intercommunication of first route, third heat transfer spare through the fifth pipeline with the export intercommunication of second route, part the second segmentation pipe set up with in the third heat transfer spare.

Optionally, in the above-mentioned coal fired power plant starting process flue gas auxiliary heating system, the heat exchange system further includes a third switch, and the third switch is arranged on the fifth pipeline and is used for controlling the on-off between the second passage and the third heat exchange.

Optionally, the above-mentioned coal fired power plant starting process flue gas auxiliary heating system, heat exchange system still includes:

one end of the sixth pipeline is communicated with the second heat exchange piece, the other end of the sixth pipeline is suitable for being communicated with one end, far away from the first heat exchange piece, of the second pipeline, and a first air inlet is formed in the sixth pipeline;

and one end of the seventh pipeline is communicated with the third heat exchange part, and the other end of the seventh pipeline is communicated with the first air inlet.

Optionally, the above-mentioned coal fired power plant starting process flue gas auxiliary heating system further includes:

the fifth pipeline is provided with a second air inlet, one end of the eighth pipeline is communicated with the fifth pipeline, and the other end of the eighth pipeline is communicated with an air inlet of the boiler;

and the fourth switching element is arranged on the eighth pipeline and used for controlling the on-off between the air preheater and the air inlet of the boiler.

Optionally, the above-mentioned coal fired power plant starting process flue gas auxiliary heating system still includes the generator, the generator pass through the drive shaft with the low pressure jar is connected, just intermediate pressure jar and high pressure jar all set up in on the drive shaft.

The technical scheme provided by the utility model, following advantage has:

1. the utility model provides a pair of coal fired power plant start-up process flue gas auxiliary heating system, including boiler, heat transfer system and turboset, heat transfer system includes first heat transfer spare, second heat transfer spare and forced draught blower, first heat transfer spare is suitable for through first pipeline with the exhanst gas outlet intercommunication, and be equipped with first passageway in the first heat transfer spare, the import of first passageway is through second pipeline and external intercommunication, the export of first passageway through third pipeline with second heat transfer spare intercommunication, the forced draught blower sets up on the second pipeline; the steam turbine set comprises a low-pressure cylinder, the low-pressure cylinder is suitable for being communicated with the steam outlet through the fourth pipeline, and part of the fourth pipeline is arranged in the second heat exchange piece.

The coal fired power plant starting process flue gas auxiliary heating system of this structure, in the unit starting process, flue gas input first heating member that produces the boiler, thereby make the temperature rise in the first heat transfer spare, the forced draught blower extracts external air and sends into in the first passageway through the second pipeline, because first passageway is located first heat transfer spare, thereby make the air through first passageway promote the temperature, the air that will promote the temperature passes through in the third pipeline input second heat transfer spare, the air that promotes the temperature makes the temperature rise in the second heat transfer spare, when steam gets into the fourth pipeline that is located the second heat transfer spare, make this steam heat up, thereby make the steam temperature that has improved the entering low pressure cylinder, and then the start-up time of steam turbine has been reduced, the start-up energy consumption of unit has been reduced.

2. The utility model provides a coal fired power plant start-up process flue gas auxiliary heating system, one end of the sixth pipeline is communicated with the second heat exchange piece, the other end of the sixth pipeline is suitable for being communicated with one end of the second pipeline far away from the first heat exchange piece, and the sixth pipeline is provided with a first air inlet; one end of the seventh pipeline is communicated with the third heat exchange part, and the other end of the seventh pipeline is communicated with the first air inlet. Through carrying out recycle to the air after releasing heat in second heat transfer spare and the third heat transfer spare, reduced the waste heat loss of air, improved the economic nature of power plant.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is the utility model provides a pair of coal fired power plant starting process flue gas auxiliary heating system's schematic diagram.

Description of the reference numerals:

1. a boiler; 11. a flue gas outlet; 12. a steam outlet; 13. an air inlet;

21. a first heat exchange member; 22. a second heat exchange member; 23. a first conduit; 231. a fourth sectional tube; 232. a fifth segmented tube; 24. a second conduit; 241. a blower; 25. a third pipeline; 251. a second switching member; 26. an air preheater; 27. a third heat exchange member; 28. a fifth pipeline; 281. a third switching member; 282. a second air inlet; 291. a sixth pipeline; 2911. a first air inlet; 292. a seventh pipe;

31. a low pressure cylinder; 32. a fourth conduit; 321. a first sectioned pipe; 3211. a first switching member; 322. a second sectioned pipe; 323. a third sectional pipe; 33. a high pressure cylinder; 34. an intermediate pressure cylinder;

4. an eighth conduit; 41. a fourth switching element;

5. a generator; 51. a drive shaft.

Detailed Description

The technical solutions of the present invention will be described more clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

The embodiment provides a flue gas auxiliary heating system for a coal-fired power plant starting process, as shown in fig. 1, the flue gas auxiliary heating system comprises a boiler 1, a heat exchange system and a steam turbine unit, the heat exchange system comprises a first heat exchange part 21, a second heat exchange part 22 and a blower 241, the first heat exchange part 21 is suitable for being communicated with a flue gas outlet 11 through a first pipeline 23, a first passage is arranged in the first heat exchange part 21, an inlet of the first passage is communicated with the outside through a second pipeline 24, an outlet of the first passage is communicated with the second heat exchange part 22 through a third pipeline 25, and the blower 241 is arranged on the second pipeline 24; the steam turbine comprises a low pressure cylinder 31, the low pressure cylinder 31 being adapted to communicate with the steam outlet 12 via a fourth conduit 32, and a part of the fourth conduit 32 being arranged inside the second heat exchanger 22.

The coal fired power plant start-up process flue gas auxiliary heating system that this embodiment provided, coal fired power plant start-up process flue gas auxiliary heating system, in unit start-up process, with the flue gas input first heating element that boiler 1 produced, thereby make the temperature rise in the first heat transfer piece 21, forced draught blower 241 extracts in the outside air sends into in the first passageway through second pipeline 24, because the first passageway is located first heat transfer piece 21, thereby make the air through the first passageway promote the temperature, the air that will promote the temperature passes through third pipeline 25 input second heat transfer piece 22 in, the air that promotes the temperature makes the temperature rise in the second heat transfer piece 22, when steam gets into the fourth pipeline 32 that is located second heat transfer piece 22, make this steam heat up, thereby make the steam temperature that gets into in low pressure cylinder 31 improved, and then reduced the start-up time of steam turbine, the start-up energy consumption of unit has been reduced.

As shown in fig. 1, in the coal fired power plant startup process flue gas auxiliary heating system provided by this embodiment, the first heat exchange member 21 is a tank body made of a heat insulating material, the second heat exchange member 22 is also a tank body made of a heat insulating material, the tank body is also made of a heat insulating material, the first passage is a metal pipeline, the first passage is located in the first heat exchange member 21, the air blower 241 is configured to draw outside air and convey the air into the first passage, because flue gas generated by the boiler 1 is introduced into the first heat exchange member 21, the air passing through the first passage is heated by the flue gas to form heated air, steam passes through the low pressure cylinder 31 and then is conveyed into a condenser (not shown in the drawing), the first heat exchange member 21 is provided with a smoke exhaust port, and the flue gas cooled in the first heat exchange member 21 is exhausted to the outside through the smoke exhaust port.

As shown in fig. 1, the coal fired power plant starting process flue gas auxiliary heating system provided in this embodiment, the steam turbine further includes a high pressure cylinder 33, an intermediate pressure cylinder 34 and a first switch 3211, the fourth pipeline 32 is divided into a first sectional pipe 321, a second sectional pipe 322 and a third sectional pipe 323, one end of the first sectional pipe 321 is communicated with the steam outlet 12, the other end of the first sectional pipe 321 is communicated with the high pressure cylinder 33, one end of the second sectional pipe 322 is communicated with the high pressure cylinder 33, the other end of the second sectional pipe 322 is communicated with the intermediate pressure cylinder 34, one end of the third sectional pipe 323 is communicated with the intermediate pressure cylinder 34, the other end of the third sectional pipe 323 is communicated with the low pressure cylinder 31, and a part of the third sectional pipe 323 is disposed in the second heat exchanging member 22. That is, the steam generated from the boiler 1 passes through the steam outlet 12, the first divided pipe 321, the high pressure cylinder 33, the second divided pipe 322, the intermediate pressure cylinder 34, the third divided pipe 323, and the low pressure cylinder 31 in this order. The heated air in the first path is input into the second heat exchanging element 22 through the third sectional pipe 323, and since part of the third sectional pipe 323 is located in the second heat exchanging element 22, the steam passing through the third sectional pipe 323 is heated by the heated air, so that the steam entering the low pressure cylinder 31 has a higher temperature, and the steam parameters for preheating the steam turbine are improved. The first switching member 3211 is a valve body, and the first switching member 3211 is disposed on the first segment pipe 321 to control an amount of steam entering the high pressure cylinder 33.

As shown in fig. 1, in the coal-fired power plant startup process flue gas auxiliary heating system provided by this embodiment, the heat exchange system further includes a second switch 251, an air preheater 26, a third heat exchange 27, a third switch 281, a sixth pipeline 291, and a seventh pipeline 292, the second switch 251 is disposed on the third pipeline 25, and is used for controlling the amount of the heated air entering the second heat exchange 22 through the first passage. The air preheater 26 is a rotary air preheater 26, the rotary air preheater 26 has a heating surface through which flue gas and air alternately flow, when the flue gas flows, heat is transferred from the flue gas to the heating surface, the temperature of the heating surface is raised, and heat is accumulated; when the air flows through again, the heat receiving surface gives off the accumulated heat to the air. First pipeline 23 divide into fourth subsection pipe 231 and fifth subsection pipe 232, fourth subsection pipe 231 one end and 11 intercommunications of exhanst gas outlet, the fourth subsection other end and air heater 26 intercommunication, fifth subsection pipe 232 one end and air heater 26 intercommunication, the fifth subsection pipe 232 other end and first heat transfer piece 21 intercommunication, set up the second route in the air heater 26, the import and the export intercommunication of first route of second route, third heat transfer piece 27 is through the export intercommunication of fifth pipeline 28 with the second route, part second subsection pipe 322 sets up and exchanges in the piece 27 with the third. The third switching part 281 is provided on the fifth duct 28 for controlling the amount of the high temperature air introduced into the third heat exchanging element 27 through the second path. One end of the sixth pipeline 291 is communicated with the second heat exchanging element 22, the other end of the sixth pipeline 291 is suitable for being communicated with one end of the second pipeline 24 far away from the first heat exchanging element 21, a first air inlet 2911 is arranged on the sixth pipeline 291, one end of the seventh pipeline 292 is communicated with the third heat exchanging element 27, and the other end of the seventh pipeline 292 is communicated with the first air inlet 2911.

As shown in fig. 1, the flue gas auxiliary heating system for the coal-fired power plant starting process provided by this embodiment further includes an eighth pipe 4, the fifth pipe 28 is provided with a second air inlet 282, one end of the eighth pipe 4 is communicated with the fifth pipe 28, and the other end of the eighth pipe 4 is communicated with the air inlet 13 of the boiler 1; a fourth switching element 41 is provided on the eighth duct 4 for controlling the amount of the high temperature air in the air preheater 26 entering the air inlet 13 of the boiler 1. When the amount of air in the air preheater 26 is sufficient, the high-temperature air in the air preheater 26 enters the boiler 1 through the eighth pipe 4, so that the air entering the boiler 1 is preheated, the ignition point is reduced, and the fuel in the boiler 1 is fully combusted.

As shown in fig. 1, the coal-fired power plant startup process flue gas auxiliary heating system provided by this embodiment further includes a generator 5, the generator 5 is connected with the low-pressure cylinder 31 through a driving shaft 51, and the intermediate-pressure cylinder 34 and the high-pressure cylinder 33 are both disposed on the driving shaft 51. Steam generated by the boiler 1 enters the high pressure cylinder 33 through the first sectional pipe 321 and works the high pressure cylinder 33, so that the high pressure cylinder 33 drives the driving shaft 51 to rotate, the steam passing through the high pressure cylinder 33 enters the intermediate pressure cylinder 34 through the second sectional pipe 322, because part of the second section is located in the third heating element, the temperature of the steam entering the intermediate pressure cylinder 34 is increased, so that the work of the intermediate pressure cylinder 34 is increased, so that the intermediate pressure cylinder 34 drives the driving shaft 51 to rotate, the steam passing through the intermediate pressure cylinder 34 enters the low pressure cylinder 31 through the third sectional pipe 323, because part of the third section is located in the second heating element, the temperature of the steam entering the low pressure cylinder 31 is increased, so that the work of the low pressure cylinder 31 is increased, the low pressure cylinder 31 drives the driving shaft 51 to rotate, and the driving shaft 51 drives the generator 5 to rotate and generate electric energy.

The coal fired power plant start-up process flue gas auxiliary heating system that this embodiment provided, its work engineering is as follows:

in the starting process of the unit, the first switch 3211, the second switch 251 and the third switch 281 are turned on, meanwhile, the blower 241 starts to operate, steam generated by the boiler 1 sequentially passes through the steam outlet 12, the first sectional pipe 321, the high pressure cylinder 33, the second sectional pipe 322, the intermediate pressure cylinder 34, the third sectional pipe 323 and the low pressure cylinder 31 and then is input into the condenser, flue gas generated by the boiler 1 enters the fourth sectional pipe 231 from the flue gas outlet 11, enters the air preheater 26 through flue gas of the fourth sectional pipe 231, flue gas in the air preheater 26 enters the first heat exchange member 21 through the fifth sectional pipe 232 and then is discharged from a smoke discharge port on the first heat exchange member 21, air extracted by the blower 241 is conveyed into the first passage through the second pipe 24, because the first passage is located in the first heat exchange member 21, the first passage exchanges heat with flue gas in the first heat exchange member 21 and then becomes heated air, and part of the heated air is input into the third heat exchange member 25, and the temperature of the steam in the third sectional pipe 323 rises; in the air admission second passageway after the other part intensification in the first heat transfer piece 21, make the air temperature after the intensification further improve to become high temperature air in the air heater 26, high temperature air gets into third heat transfer piece 27 through fifth pipeline 28 in, this high temperature air and the steam heat transfer in the part second subsection pipe 322 for the steam temperature in this part second subsection pipe 322 risees, thereby realizes promoting the temperature that gets into steam in the steam turbine.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.

Claims (10)

1. The utility model provides a coal fired power plant start-up process flue gas auxiliary heating system which characterized in that includes:

a boiler (1), the boiler (1) having a flue gas outlet (11) and a steam outlet (12);

the heat exchange system comprises a first heat exchange piece (21), a second heat exchange piece (22) and a blower (241), wherein the first heat exchange piece (21) is suitable for being communicated with the flue gas outlet (11) through a first pipeline (23), a first passage is arranged in the first heat exchange piece (21), an inlet of the first passage is communicated with the outside through a second pipeline (24), an outlet of the first passage is communicated with the second heat exchange piece (22) through a third pipeline (25), and the blower (241) is arranged on the second pipeline (24);

the steam turbine set comprises a low-pressure cylinder (31), the low-pressure cylinder (31) is suitable for being communicated with the steam outlet (12) through a fourth pipeline (32), and part of the fourth pipeline (32) is arranged in the second heat exchange part (22).

2. The coal-fired power plant starting process flue gas auxiliary heating system of claim 1, wherein the steam turbine unit further comprises a high pressure cylinder (33) and a medium pressure cylinder (34), the fourth pipeline (32) is divided into a first sectional pipe (321), a second sectional pipe (322) and a third sectional pipe (323), the high pressure cylinder (33) is communicated with the steam outlet (12) through the first sectional pipe (321), one end of the second sectional pipe (322) is communicated with the high pressure cylinder (33), the other end of the second sectional pipe (322) is communicated with the medium pressure cylinder (34), one end of the third sectional pipe (323) is communicated with the medium pressure cylinder (34), the other end of the third sectional pipe (323) is communicated with the low pressure cylinder (31), and part of the third sectional pipe (323) is arranged in the second heat exchange member (22).

3. The coal fired power plant startup process flue gas auxiliary heating system of claim 2, characterized in that the steam turbine unit further comprises a first switch member (3211), and the first switch member (3211) is disposed on the first segment pipe (321) for controlling on/off between the steam outlet (12) and the high pressure cylinder (33).

4. The coal fired power plant start-up process flue gas auxiliary heating system of claim 2, characterized in that the heat exchange system further comprises a second switching member (251), the second switching member (251) being provided on the third pipe (25) for controlling the on-off between the first passage and the second heat exchange member (22).

5. The coal fired power plant start-up process flue gas auxiliary heating system of claim 2, the heat exchange system further comprises an air preheater (26), the first pipeline (23) is divided into a fourth sectional pipe (231) and a fifth sectional pipe (232), one end of the fourth sectional pipe (231) is communicated with the flue gas outlet (11), the other end of the fourth sectional pipe (231) is communicated with the air preheater (26), one end of the fifth sectional pipe (232) is communicated with the air preheater (26), and the other end of the fifth sectional pipe (232) is communicated with the first heat exchanging piece (21).

6. The coal fired power plant startup process flue gas auxiliary heating system of claim 5, wherein the heat exchange system further comprises a third heat exchange member (27), a second passage is provided in the air preheater (26), an inlet of the second passage is communicated with an outlet of the first passage, the third heat exchange member (27) is communicated with an outlet of the second passage through a fifth pipe (28), and a part of the second sectional pipe (322) is provided in the third heat exchange member (27).

7. The coal-fired power plant start-up process flue gas auxiliary heating system of claim 6, characterized in that the heat exchange system further comprises a third switching element (281), and the third switching element (281) is arranged on the fifth pipeline (28) and used for controlling the on-off between the second passage and the third heat exchange element (27).

8. The coal fired power plant startup process flue gas auxiliary heating system of claim 6, the heat exchange system further comprising:

a sixth pipeline (291), one end of the sixth pipeline (291) is communicated with the second heat exchange part (22), the other end of the sixth pipeline (291) is suitable for being communicated with one end, away from the first heat exchange part (21), of the second pipeline (24), and a first air inlet (2911) is arranged on the sixth pipeline (291);

a seventh conduit (292), one end of the seventh conduit (292) being in communication with the third heat transfer element (27), the other end of the seventh conduit (292) being in communication with the first air inlet (2911).

9. The coal fired power plant startup process flue gas auxiliary heating system of claim 6, further comprising:

the second air inlet (282) is formed in the fifth pipeline (28), one end of the eighth pipeline (4) is communicated with the fifth pipeline (28), and the other end of the eighth pipeline (4) is communicated with the air inlet (13) of the boiler (1);

a fourth switching element (41), the fourth switching element (41) is arranged on the eighth pipeline (4) and is used for controlling the on-off between the air preheater (26) and the air inlet (13) of the boiler (1).

10. Coal fired power plant start-up process flue gas auxiliary heating system according to any of claims 2 to 9, characterized by further comprising an electric generator (5), the electric generator (5) being connected with the low pressure cylinder (31) by a drive shaft (51), and the intermediate pressure cylinder (34) and the high pressure cylinder (33) being both arranged on the drive shaft (51).

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