Cold air heating system for air-cooled desuperheater of power station boiler reheater
By introducing an air-cooled desuperheater system into the reheater of a power plant boiler, the steam temperature is regulated by heat exchange between extracted steam and cold air, thus solving the problem of low thermal efficiency in existing technologies and improving boiler thermal efficiency and economy.
Patent Information
- Application Number
- CN202511175075.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2025-11-21
AI Technical Summary
Existing power plant boiler reheaters often rely on oscillating burners or emergency desuperheating water to regulate reheat steam temperature, resulting in reduced thermal efficiency and increased coal consumption for power generation in the long run.
The system employs an air-cooled desuperheater, which extracts reheat steam and exchanges heat with cold air to return the heat to the boiler furnace, regulates the steam temperature, and reduces the amount of water sprayed. Combined with the boiler's secondary air inlet duct, it improves the heat utilization rate.
It improved boiler thermal efficiency, reduced coal consumption for power generation, and enhanced the economic efficiency of power plant boilers.
Smart Images
Figure CN120991289A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of power station boiler reheater, in particular to a cold air heating system of a power station boiler reheater air cooling temperature reducer. BACKGROUND
[0002] The existing power station boiler, especially the subcritical boiler, often uses the swing burner mode for reheater steam temperature regulation, and is equipped with an emergency temperature reducing water as a backup means, which is only used in emergency situations. However, in actual operation, due to the frequent problems of the burner swing actuator, such as being stuck, the temperature cannot be normally adjusted, and the adjustment effect of the swing temperature regulation is lagging, so many power plants basically abandon the burner swing adjustment mode and use water spray temperature reduction to adjust the reheater steam temperature.
[0003] In the modification project of reheater cold end extraction steam for industrial steam, steam is extracted from the reheater side for industrial steam use, and the power plant side hopes that the extraction steam quantity is as large as possible, so as to provide greater economic benefits. However, in the case of a large extraction steam quantity, a large amount of water must be sprayed to reduce the temperature of the reheater, so as to ensure that the flow and temperature of the working medium in the reheater are sufficient to cool the heating surface and ensure the safety of the pipe wall temperature.
[0004] Therefore, the above two cases will reduce the thermal efficiency of the unit when a large amount of water is sprayed to the reheater, and long-term use will greatly reduce the economy of the unit and increase the coal consumption of power generation. SUMMARY
[0005] Therefore, the present application aims to provide a cold air heating system of a power station boiler reheater air cooling temperature reducer to solve the problem that a large amount of water sprayed to the reheater will reduce the thermal efficiency of the unit, and long-term use will greatly reduce the economy of the unit and increase the coal consumption of power generation.
[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: a cold air heating system of a power station boiler reheater air cooling temperature reducer, which comprises a boiler reheater system, an extraction steam inlet pipeline, an air cooling heat exchanger and an extraction steam outlet pipeline, the air cooling heat exchanger is arranged on the boiler secondary air inlet air duct, the inlet end of the boiler reheater system is provided with a reheater inlet pipeline, the inlet end of the extraction steam inlet pipeline is connected with the reheater inlet pipeline, the outlet end of the extraction steam inlet pipeline is connected with the inlet end of the air cooling heat exchanger, the outlet end of the air cooling heat exchanger is connected with the inlet end of the extraction steam outlet pipeline, and the outlet end of the extraction steam outlet pipeline is connected with the reheater inlet pipeline and the boiler reheater system. Further, the air cooling heat exchanger is a serpentine tube heat exchanger.
[0007] Further, the extraction steam inlet pipeline is provided with an adjusting valve.
[0008] Further, the boiler reheater system comprises a wall radiation reheater, a screen reheater and a final stage reheater connected in sequence, and the reheater inlet pipeline is connected with the wall radiation reheater.
[0009] Further, the outlet end of the steam extraction outlet pipeline is connected with a boiler reheater connecting pipe, and the outlet end of the steam extraction outlet pipeline is connected with the boiler reheater inlet pipeline and the screen reheater inlet through the boiler reheater connecting pipe.
[0010] Further, a rotary air preheater is arranged on the boiler secondary air inlet air duct, and the rotary air preheater is connected with the tail flue of the boiler.
[0011] Further, a reheater desuperheater is arranged on the reheater inlet pipeline.
[0012] Compared with the prior art, the present application has the following beneficial effects: 1. The present application provides a power station boiler reheater air cooling desuperheater cold air heating system, a part of reheated steam is extracted from the reheater inlet pipeline through the steam extraction inlet pipeline, and the excess heat is sent back to the boiler furnace through heat exchange with the cold air at the boiler inlet, so that the reheated steam temperature can be reduced, the steam temperature can be adjusted, the reheater desuperheater water amount can be reduced or eliminated, and the influence of long-term large amount of reheater water injection desuperheating on the thermal efficiency of the unit can be reduced or eliminated. 2. The present application provides a power station boiler reheater air cooling desuperheater cold air heating system, and the excess heat of the reheater is sent back to the boiler through the boiler secondary air inlet air duct, so that the inlet air temperature of the secondary air is improved, and the thermal efficiency of the boiler is improved, that is, the economy of the long-term operation of the power station boiler is improved. BRIEF DESCRIPTION OF DRAWINGS
[0013] The accompanying drawings, which form a part of the present application, are used to provide a further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings: Figure 1 It is a whole structure schematic view of the power station boiler reheater air cooling desuperheater cold air heating system.
[0014] 1-steam extraction inlet pipeline, 2-air cooling heat exchanger, 3-steam extraction outlet pipeline, 4-boiler secondary air inlet air duct, 5-reheater inlet pipeline, 6-regulating valve, 7-wall radiation reheater, 8-screen reheater, 9-final stage reheater, 10-boiler reheater connecting pipe, 11-rotary air preheater, 12-tail flue, 13-reheater desuperheater, 14-furnace. DETAILED DESCRIPTION
[0015] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.
[0016] Referring to Figure 1 The present embodiment is described as follows: a cold air heating system of a power station boiler reheater air cooling temperature reducer, which comprises a boiler reheater system, a steam extraction inlet pipeline 1, an air cooling heat exchanger 2 and a steam extraction outlet pipeline 3. The air cooling heat exchanger 2 is arranged on a boiler secondary air inlet air duct 4. An inlet end of the boiler reheater system is provided with a reheater inlet pipeline 5. An outlet end of the steam extraction inlet pipeline 1 is connected with the reheater inlet pipeline 5. The outlet end of the steam extraction inlet pipeline 1 is connected with an inlet end of the air cooling heat exchanger 2. An outlet end of the air cooling heat exchanger 2 is connected with an inlet end of the steam extraction outlet pipeline 3. The outlet end of the steam extraction outlet pipeline 3 is connected with the reheater inlet pipeline 5 and the boiler reheater system. A part of reheated steam is extracted from the reheater inlet pipeline 5 through the steam extraction inlet pipeline 1, and heat exchange is performed between the part of reheated steam and cold air at the boiler inlet. The excess heat of the part of reheated steam is sent back into a boiler furnace 14, so that the reheated steam temperature can be reduced, the steam temperature can be adjusted, the reheater temperature reducing water amount can be reduced or eliminated, the influence of long-term large amount of water injection for temperature reduction of the reheater on the thermal efficiency of the unit can be reduced or eliminated, and the excess heat of the reheater is sent back into the boiler through the boiler secondary air inlet air duct 4, the inlet air temperature of the secondary air is increased, and thus the thermal efficiency of the boiler is improved, that is, the economy of long-term operation of the power station boiler is improved.
[0017] In the present embodiment, the air cooling heat exchanger 2 is a serpentine tube heat exchanger. The reheated steam passes through the tubes, and the cold secondary air transversely washes the outside of the tubes, so that heat exchange is realized.
[0018] In the present embodiment, the steam extraction inlet pipeline 1 is provided with an adjusting valve 6. The adjusting valve 6 can adjust the flow of the reheated steam, so as to control the amplitude of the reheated steam temperature reduction.
[0019] In the present embodiment, the boiler reheater system comprises a wall type radiation reheater 7, a screen type reheater 8 and a final stage reheater 9 which are connected in sequence. The reheater inlet pipeline 5 is connected with the wall type radiation reheater 7.
[0020] In the present embodiment, the outlet end of the steam extraction outlet pipeline 3 is connected with a boiler reheater connecting pipeline 10. The outlet end of the steam extraction outlet pipeline 3 is connected with the reheater inlet pipeline 5 and the inlet of the screen type reheater 8 through the boiler reheater connecting pipeline 10. The boiler reheater connecting pipeline 10 guides the part of cooled steam into the screen type reheater 8. The part of low-temperature steam plays a role of reducing the temperature of the whole reheated steam. Another part of the cooled steam is returned to the reheater inlet pipeline 5 to be mixed with the high-temperature reheated steam.
[0021] The boiler secondary air inlet duct 4 is provided with a rotary air preheater 11, which is connected with the tail flue 12 of the boiler.
[0022] The reheater inlet pipeline 5 is provided with a reheater desuperheater 13, which is used for emergency cooling of the reheater inlet pipeline 5.
[0023] The working principle of the embodiment is as follows: The steam extraction inlet pipeline 1 extracts a part of the reheated steam of the reheater inlet pipeline 5 and sends it to the air-cooled heat exchanger 2 arranged on the boiler secondary air inlet duct 4, and the reheated steam exchanges heat with the cold air in the boiler secondary air inlet duct 4. Since the temperature of the cold air is very low, approximately equal to the ambient temperature, the reheated steam is rapidly cooled and sent to the boiler reheater connecting pipe 10 in the boiler through the steam extraction outlet pipeline 3 connected with the outlet of the air-cooled heat exchanger 2. The cooled part of the steam enters the screen-type reheater 8, and this part of the low-temperature steam plays a role in reducing the temperature of the entire reheated steam. Another part of the cooled steam returns to the reheater inlet pipeline 5 and mixes with the high-temperature reheated steam.
[0024] The boiler secondary air heated by the steam improves the air inlet temperature of the boiler rotary air preheater 11, which is equivalent to bringing a part of heat gain to the boiler. Although the exhaust gas temperature of the boiler rises slightly, the exhaust gas loss is less than the heat gain, so the overall calculation shows that the efficiency of the boiler is improved.
[0025] The original emergency water spray desuperheater of the boiler in the embodiment is still retained as an emergency backup. In terms of operation control, the air-cooled desuperheater can be set as the preferred method for adjusting the reheated steam temperature, and the emergency desuperheating water is used as a backup means.
[0026] Taking a 300MW subcritical boiler as an example, 50t / h of steam is extracted from the reheater inlet, which accounts for about 5% of the total flow of the reheater, which can ensure the safety of the wall-type radiant reheater. After passing through the air-cooled heat exchanger 2, the steam temperature is reduced to 250℃, and then sent to the inlet of the screen-type reheater 8, which can reduce the inlet steam temperature of the screen-type reheater 8 by 11℃, that is, the temperature adjustment range can reach 11℃. The pressure of the 5% steam after passing through the resistance of the steam extraction pipeline and the heat exchanger is higher than the inlet pressure of the screen-type reheater 8 after preliminary calculation, which can be sent to the screen-type reheater 8 to ensure that it can be realized. In addition, since the steam parameters at the reheater inlet are low, carbon steel materials can be used for the steam extraction pipeline and the air-cooled heat exchanger, which reduces the cost of the modification.
[0027] The above disclosed embodiments of the present application are only used to help explain the present application. The embodiments do not describe all the details of the present application, and the present application is not limited to the specific embodiments described. According to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application.
Claims
1. A cold air heating system for a reheater air-cooled desuperheater in a power plant boiler, characterized in that: It includes a boiler reheater system, a steam extraction inlet pipe (1), an air-cooled heat exchanger (2) and a steam extraction outlet pipe (3), the air-cooled heat exchanger (2) is arranged on a boiler secondary air inlet air duct (4), an inlet end of the boiler reheater system is provided with a reheater inlet pipe (5), an inlet end of the steam extraction inlet pipe (1) is connected with the reheater inlet pipe (5), an outlet end of the steam extraction inlet pipe (1) is connected with an inlet end of the air-cooled heat exchanger (2), an outlet end of the air-cooled heat exchanger (2) is connected with an inlet end of the steam extraction outlet pipe (3), and an outlet end of the steam extraction outlet pipe (3) is connected with the reheater inlet pipe (5) and the boiler reheater system.
2. The air cooling attemperator cold air heating system for a reheater of a power plant boiler according to claim 1, characterized in that: The air-cooled heat exchanger (2) is a serpentine pipe heat exchanger.
3. The air cooling attemperator cold air heating system for a reheater of a power plant boiler according to claim 1, characterized in that: An adjusting valve (6) is arranged on the steam extraction inlet pipe (1).
4. The air cooling attemperator cold air heating system of a reheat section of a power plant boiler according to claim 1, characterized in that: The boiler reheater system comprises a wall type radiation reheater (7), a screen type reheater (8) and a final stage reheater (9) connected in sequence, and the reheater inlet pipe (5) is connected with the wall type radiation reheater (7).
5. The air-cooled attemperator cold air heating system of a reheat section of a utility boiler according to claim 4, characterized in that: A boiler reheater connecting pipe (10) is connected with the outlet end of the steam extraction outlet pipe (3), and the outlet end of the steam extraction outlet pipe (3) is connected with the boiler reheater inlet pipe (5) and the screen type reheater (8) inlet through the boiler reheater connecting pipe (10).
6. The air cooling attemperator cold air heating system of a reheat air heater of a power station boiler according to claim 5, characterized in that: A rotary air preheater (11) is arranged on the boiler secondary air inlet air duct (4), and the rotary air preheater (11) is connected with a tail flue (12) of the boiler.
7. The air-cooled attemperator cold air heating system of a reheat section of a utility boiler according to claim 6, characterized in that: A reheater desuperheater (13) is arranged on the reheater inlet pipe (5).