Turbine intermediate exhaust industrial heat supply system for novel electric power system
By setting up butterfly valves and small steam turbines in the medium-discharge industrial heating system of the new power system, the problem of reducing heating capacity and large vibration in the medium-discharge heating system under deep-regulated or large flow heating conditions is solved, and the unit's heating capacity is guaranteed and the vibration is reduced, ensuring safe operation.
Patent Information
- Application Number
- CN202510131063.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2025-06-17
AI Technical Summary
In the new power system, under deep regulation or large flow heating conditions, the water supply pumps, steam exhaust inlets of the conventional system, and the condenser of the low-pressure cylinders of the main turbine, resulting in a reduction in the unit's external heating capacity or deep regulation amplitude, and the steam excitation force is large, resulting in the communication pipe, low-pressure cooling bypass, and cylinder vibration, affecting the safe operation of the unit.
By connecting the deaerator and the low-pressure heat recovery system in parallel at the steam extraction port of the medium-pressure cylinder, the first butterfly valve and the second butterfly valve are arranged at the communication pipe near the medium-pressure cylinder exhaust port and the low-pressure cylinder inlet port, and the exhaust steam of the small turbine is used as the low-pressure cylinder cooling steam to reduce the steam flow rate of the communication pipe entering the low-pressure cylinder, and the diameter of the designed communication pipe becomes smaller. At the same time, the pressure difference between each butterfly valve is adjusted by half, reducing the steam flow excitation force.
It effectively ensures that the unit's external heating capacity or deep adjustment amplitude does not decrease, reduces the steam excitation force, reduces the vibration of the communication pipe, low-pressure cooling bypass and cylinders, and ensures the safe operation of the unit.
Smart Images
Figure CN120159567A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of steam turbine power generation, and particularly relates to an intermediate extraction industrial heating system for a steam turbine in a new power system. Background Art
[0002] In order to adapt to the two-part electricity price and the operation of the spot market, under the condition of meeting the heating demand, the units of the new power system usually need to operate with as deep a load regulation as possible, cut the low-pressure cylinder, and keep the electrical load as low as possible; at peak times, they switch to conventional heating units, do not cut the low-pressure cylinder, and keep the electrical load as high as possible.
[0003] In actual use, during the operation of the new power system, the following problems will occur in the design of the conventional intermediate extraction industrial heating system units: 1. Under deep load regulation or large-flow heating conditions; in the conventional system, the feed water pump, the exhaust steam inlet of the steam turbine, and the condenser, etc. do not use the cooling steam of the low-pressure cylinder of the main steam turbine, and it is still necessary to add a pressure-reducing cooling device, a bypass, or an extraction steam from a small steam turbine in the intermediate extraction to cool the low-pressure cylinder, resulting in a reduction in the external heating capacity or the amplitude of deep load regulation of the unit.
[0004] 2. To balance the pure condensing and heating conditions, all the steam in the low-pressure regenerative heating system enters the low-pressure cylinder through the connecting pipe and is then extracted section by section, resulting in a relatively large diameter design of the connecting pipe; When the extraction steam volume is large or during low-electrical-load heating, the pressure difference before and after the butterfly valve of the connecting pipe and the butterfly valve of the low-pressure cylinder cooling bypass is large; When the large diameter of the connecting pipe and the large extraction steam volume or the large pressure difference before and after the butterfly valve of the connecting pipe and the butterfly valve of the low-pressure cylinder cooling bypass during low-electrical-load heating are superimposed, the steam excitation force will increase greatly, inducing a large over-standard vibration of the connecting pipe, the low-pressure cooling bypass, and the cylinder, affecting the safe operation of the unit. Summary of the Invention
[0005] The purpose of the present invention is: aiming at the deficiencies of the prior art, to provide an intermediate extraction industrial heating system for a steam turbine in a new power system that can ensure that the external heating capacity or the amplitude of deep load regulation of the unit will not be reduced; at the same time, reduce the steam excitation force, reduce the vibration of the connecting pipe, the low-pressure cooling bypass, and the cylinder, and ensure the safe operation of the unit.
[0006] The technical object of the present invention is achieved through the following technical solutions: An industrial heating system for the middle extraction of a steam turbine in a new power system, comprising a medium-pressure cylinder, a low-pressure cylinder, and a connecting pipe connecting the exhaust port of the medium-pressure cylinder and the steam inlet of the low-pressure cylinder. The extraction port of the medium-pressure cylinder is connected in parallel to a deaerator and a low-pressure regenerative system through a steam extraction pipeline; a first butterfly valve and a second butterfly valve are respectively arranged near the exhaust port of the medium-pressure cylinder and the steam inlet of the low-pressure cylinder on the connecting pipe; the steam inlet of a small steam turbine in the low-pressure regenerative system is connected to the first branch of the steam extraction pipeline of the steam extraction pipeline, and a steam inlet regulating valve is arranged on the first branch of the steam extraction pipeline; the exhaust port of the small steam turbine is connected in parallel to one end of the connecting pipe near the steam inlet of the low-pressure cylinder and the low-pressure final-stage low-pressure heater extraction port of the low-pressure cylinder through an exhaust pipeline.
[0007] Preferably, the low-pressure regenerative system further comprises a first low-pressure heater and a second low-pressure heater respectively connected to the first extraction port and the second extraction port of the small steam turbine through branch pipes; one end of a condensate heating pipeline is connected to the outlet of a shaft seal heater, and the other end is connected to the water inlet of the deaerator; the condensate heating pipeline between the shaft seal heater and the deaerator is connected in series between the first low-pressure heater and the second low-pressure heater.
[0008] Preferably, the first condensate water outlet of the first low-pressure heater is connected to the second low-pressure heater through a first condensate pipeline, and the second condensate water outlet of the second low-pressure heater is connected to the condensate heating pipeline between the first low-pressure heater and the second low-pressure heater through a second condensate pipeline.
[0009] Preferably, the number of stages of the low-pressure heater is set to 2, 3, or 4 levels according to specific conditions.
[0010] Preferably, the low-pressure regenerative system further comprises a feed water pump connected to one end of the rotating shaft of the small steam turbine, and the other end of the rotating shaft away from the feed water pump is connected to a constant-speed generator / motor.
[0011] Preferably, a speed regulating device is further arranged between the constant-speed generator / motor and the rotating shaft. One end of the speed regulating device is connected to the constant-speed generator / motor, and the other end is connected to the rotating shaft.
[0012] Preferably, the exhaust pipeline comprises an exhaust main pipeline and a steam inlet branch of the low-pressure cylinder and a steam extraction branch of the low-pressure cylinder connected in parallel to the exhaust main pipeline; one end of the steam inlet branch of the low-pressure cylinder is connected to the exhaust main pipeline, and the other end is connected to one end of the connecting pipe near the steam inlet of the low-pressure cylinder; one end of the steam extraction branch of the low-pressure cylinder is connected to the exhaust main pipeline, and the other end is connected to the conventional low-pressure final-stage low-pressure heater extraction port; a first pressure regulating valve and a second pressure regulating valve are respectively arranged on the steam inlet branch of the low-pressure cylinder and the steam extraction branch of the low-pressure cylinder.
[0013] Preferably, the first butterfly valve is a butterfly valve with a large passage even in the fully closed state; the second butterfly valve is a butterfly valve with a smaller passage even in the fully closed state.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The steam consumption of the low-pressure regenerative system of the present invention is extracted after the small steam turbine does work, and no longer enters the low-pressure cylinder through the connecting pipe, so that the steam flow rate entering the low-pressure cylinder of the main steam turbine through the connecting pipe is reduced, thereby reducing the design size of the connecting pipe diameter; at the same time, butterfly valves are provided at both the exhaust port of the intermediate-pressure cylinder and the steam inlet of the low-pressure cylinder, and two butterfly valves are used for adjustment, so that the pressure difference of each butterfly valve is reduced by half; the reduction of the connecting pipe diameter and the reduction of the butterfly valve pressure difference greatly reduce the steam flow excitation force, avoiding the problems of large vibration of the connecting pipe, low-pressure cooling bypass and cylinder. By adopting this technical measure, the problems of large vibration of the connecting pipe, low-pressure cooling bypass and cylinder caused by deep regulation or peak shaving and heat supply operation under the middle extraction of the new power system unit are solved. Therefore, the present invention has the advantages of ensuring that the heat supply capacity or deep regulation range of the unit will not be reduced; at the same time, it has the advantages of reducing the steam excitation force, reducing the vibration of the connecting pipe, low-pressure cooling bypass and cylinder, and ensuring the safe operation of the unit. Description of the Drawings
[0015] Figure 1 is a schematic structural diagram of the present invention; Reference numerals: 1 - intermediate-pressure cylinder; 11 - main steam extraction pipeline; 12 - first steam extraction branch; 13 - second steam extraction branch; 14 - steam inlet regulating valve; 2 - low-pressure cylinder; 3 - connecting pipe; 31 - first butterfly valve; 32 - second butterfly valve; 33 - first pressure gauge; 34 - second pressure gauge; 35 - third pressure gauge; 4 - deaerator; 5 - small steam turbine; 51 - feed water pump; 52 - constant speed generator / motor; 53 - speed regulating device; 54 - first low-pressure heater; 541 - first condensate pipeline; 55 - second low-pressure heater; 551 - second condensate pipeline; 552 - drain pump; 6 - exhaust pipeline; 61 - main exhaust pipeline; 62 - steam inlet branch of low-pressure cylinder; 621 - first pressure regulating valve; 63 - steam extraction branch of low-pressure cylinder; 631 - second pressure regulating valve; 7 - condensate heating pipeline. Detailed Embodiments
[0016] To make the objectives, 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 accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.
[0017] Accordingly, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.
[0018] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.
[0019] As Figure 1 shown, an intermediate extraction industrial heating system for a steam turbine in a new power system includes an intermediate pressure cylinder 1, a low pressure cylinder 2, and a connecting pipe 3 connecting the exhaust port of the intermediate pressure cylinder and the steam inlet of the low pressure cylinder; the extraction port of the intermediate pressure cylinder 1 is connected in parallel to a deaerator 4 and a low pressure regenerative system through a steam extraction pipeline; a first butterfly valve 31 and a second butterfly valve 32 are respectively arranged near the exhaust port of the intermediate pressure cylinder and the steam inlet of the low pressure cylinder on the connecting pipe 3; the steam inlet of a small steam turbine 5 in the low pressure regenerative system is connected to the first steam extraction branch 12 of the steam extraction pipeline, and a steam inlet regulating valve 14 is provided on the first steam extraction branch 12; the exhaust port of the small steam turbine 5 is connected in parallel to one end of the connecting pipe 3 near the steam inlet of the low pressure cylinder and the low pressure final stage low pressure heater extraction port of the low pressure cylinder 2 through an exhaust pipeline 6. By using the exhaust steam of the small steam turbine 5 as the cooling steam for bypassing the low pressure cylinder 2, the heating capacity or the peak shaving depth is increased, and the system is simple and efficient.
[0020] Specifically, the steam consumption of the low pressure regenerative system is extracted after the small steam turbine 5 does work, and no longer enters the low pressure cylinder 2 through the connecting pipe 3, so that the steam flow rate entering the low pressure cylinder 2 through the connecting pipe 3 is reduced, thereby reducing the design diameter of the connecting pipe 3; at the same time, butterfly valves are arranged at both the exhaust port of the intermediate pressure cylinder and the steam inlet of the low pressure cylinder, and two butterfly valves are used for adjustment, so that the pressure difference of each butterfly valve is reduced by half; the reduction of the diameter of the connecting pipe 3 and the reduction of the butterfly valve pressure difference greatly reduce the steam flow excitation force, avoiding the problems of large vibration of the connecting pipe 3, the low pressure cooling bypass, and the cylinder. By adopting this technical measure, the problems of large vibration of the connecting pipe 3, the low pressure cooling bypass, and the cylinder caused by deep regulation or peak shaving operation of the new power system unit are solved. Therefore, by adopting the above technical measures, the advantages of ensuring that the external heating capacity or the deep regulation range of the unit will not be reduced are achieved; at the same time, the advantages of reducing the steam excitation force, reducing the vibration of the connecting pipe 3, the low pressure cooling bypass, and the cylinder, and ensuring the safe operation of the unit are achieved.
[0021] The extraction port of the medium-pressure cylinder 1 is connected to the deaerator 4 and the low-pressure regenerative system in parallel through a steam extraction pipeline; the steam inlet of the small steam turbine 5 in the low-pressure regenerative system is connected to the first steam extraction branch 12 of the steam extraction pipeline. In specific implementation, the steam extraction pipeline includes a main steam extraction pipeline 11, a first steam extraction branch 12, and a second steam extraction branch 13; one end of the main steam extraction pipeline 11 is connected to the extraction port of the medium-pressure cylinder 1, and the other end is connected to the first steam extraction branch 12 and the second steam extraction branch 13 in parallel; the end of the first steam extraction branch 12 far from the main steam extraction pipeline 11 is connected to the steam inlet of the small steam turbine. The deaerator 4 includes at least one steam inlet and one water inlet. The end of the second steam extraction branch 13 far from the main steam extraction pipeline 11 is connected to the steam inlet of the deaerator 4.
[0022] A first butterfly valve 31 and a second butterfly valve 32 are respectively arranged near the exhaust port of the medium-pressure cylinder and the steam inlet of the low-pressure cylinder on the connecting pipe 3. Among them, the first butterfly valve 31 is a butterfly valve designed with a large opening degree in the fully closed position, and the second butterfly valve 32 is a butterfly valve designed with a small opening degree in the fully closed position. Specifically, the first butterfly valve 31 and the second butterfly valve 32 are specially designed as required; the first butterfly valve 31 is a butterfly valve with a large channel even in the fully closed state; the second butterfly valve 32 is a butterfly valve with a smaller channel even in the fully closed state. By adopting this technical measure, the flow capacity is stronger, and the flow rate is the same during the process. Considering that it is easier to achieve pressure regulation by the first butterfly valve 31 under a large pressure difference, and the inherent pressure loss of the first butterfly valve 31 is small under a small pressure difference.
[0023] During heating, the first butterfly valve 31 is initially adjusted and the second butterfly valve 32 is finely adjusted, and the control is carried out based on the principle that the pressure difference before and after each butterfly valve is close and the vibrations of related components such as the connecting pipe 3, the butterfly valve, the cooling bypass, and the cylinder are small. By adopting the above measures, the steam excitation force can be reduced, and the vibrations of the connecting pipe 3, the low-pressure cooling bypass, and the cylinder can be reduced.
[0024] The pressures of each section on the connecting pipe 3 are measured by pressure gauges, and the pressure differences before and after each butterfly valve are obtained therefrom. In specific implementation, an industrial heating pipeline is connected to one end of the connecting pipe 3 far from the first butterfly valve 31, and a first pressure gauge 33 is provided on the industrial heating pipeline. A second pressure gauge 34 is also provided between the first butterfly valve 31 and the second butterfly valve 32 on the connecting pipe 3, and a third pressure gauge 35 is provided on the connecting pipe 3 between the second butterfly valve 32 and the steam inlet of the low-pressure cylinder 2.
[0025] The low-pressure regenerative system further includes a first low-pressure heater 54 and a second low-pressure heater 55 respectively connected to the first steam extraction port and the second steam extraction port of the small steam turbine 5 through branch pipes; one end of the condensate heating pipeline 7 is connected to the outlet of the shaft seal heater, and the other end is connected to the water inlet of the deaerator 4; the condensate heating pipeline 7 between the shaft seal heater (not shown in the figure) and the deaerator 4 is connected in series between the first low-pressure heater 54 and the second low-pressure heater 55. In specific implementation, after the condensate flows out of the shaft seal heater outlet, it will enter the first low-pressure heater 54 and the second low-pressure heater 55 for heating and then enter the deaerator 4.
[0026] In specific implementation, the first condensate outlet of the first low-pressure heater 54 is connected to the second low-pressure heater 55 through a first condensate pipeline 541, and the second condensate outlet of the second low-pressure heater 55 is connected to the condensate heating pipeline 7 between the first low-pressure heater 54 and the second low-pressure heater 55 through a second condensate pipeline 551. Among them, a drain pump 552 is provided on the second condensate pipeline. The number of stages of the first low-pressure heater 54 and the second low-pressure heater 55 is set to 2, 3 or 4 levels according to specific conditions.
[0027] The low-pressure regenerative system further includes a feed water pump 51 connected to one end of the rotating shaft of the small steam turbine 5, and the other end of the rotating shaft away from the feed water pump 51 is connected to a constant-speed generator / motor 52. In actual use, when the output power of the steam turbine is surplus, it generates electricity as a generator, and when it is insufficient, it drives as a motor. A speed regulating device 53 is also provided between the constant-speed generator / motor 52 and the rotating shaft. One end of the speed regulating device 53 is connected to the constant-speed generator / motor 52, and the other end is connected to the rotating shaft. The feed water pump 51 and the constant-speed generator / motor 52 of the small steam turbine 5 operate in the same way as a conventional dual-drive system, and the steam inlet control valve 14 is adjusted to meet the requirements of low-pressure regenerative steam extraction, driving the feed water pump 51, generating electricity and supplying steam for cooling the low-pressure cylinder 2.
[0028] In specific implementation, the exhaust steam volume and back pressure operation of the small steam turbine 5 are allowed to fluctuate within a certain range to meet the heat transfer self-balance of the first low-pressure heater 54 and the second low-pressure heater 55; the power matching is completed by the constant-speed generator / motor 52.
[0029] The exhaust steam pipeline 6 includes an exhaust steam main pipeline 61 and a low-pressure cylinder steam inlet branch 62 and a low-pressure cylinder steam extraction branch 63 connected in parallel with the exhaust steam main pipeline 61; one end of the low-pressure cylinder steam inlet branch 62 is connected to the exhaust steam main pipeline 61, and the other end is connected to one end of the connecting pipe 3 close to the low-pressure cylinder steam inlet; one end of the low-pressure cylinder steam extraction branch 63 is connected to the exhaust steam main pipeline 61, and the other end is connected to the low-pressure final-stage low-pressure heater extraction port; a first pressure regulating valve 621 and a second pressure regulating valve 631 are respectively provided on the low-pressure cylinder steam inlet branch 62 and the low-pressure cylinder steam extraction branch 63. In specific implementation, the low-pressure final-stage low-pressure heater extraction port of the low-pressure cylinder 2 is a conventional low-pressure final-stage low-pressure heater extraction port.
[0030] The steam consumption of the low-pressure regenerative system is extracted after the small steam turbine 5 does work, and no longer enters the low-pressure cylinder 2 through the connecting pipe 3. The connecting pipe 3 is designed according to the reduced steam flow rate, and the diameter of the connecting pipe 3 can be correspondingly reduced.
[0031] In this embodiment, the operation method of the intermediate extraction industrial heating system of the steam turbine for the new power system is as follows: When the low-pressure cylinder 2 is in operation; the first pressure regulating valve 621 on the inlet branch 62 of the low-pressure cylinder is opened, and the second pressure regulating valve 631 on the extraction branch 63 of the low-pressure cylinder is fully closed; the exhaust steam of the small steam turbine 5 enters the low-pressure cylinder 2 from the inlet of the low-pressure cylinder, so as to serve as the cooling steam of the low-pressure cylinder 2.
[0032] When the low-pressure cylinder 2 is not in operation; the first pressure regulating valve 621 on the inlet branch 62 of the low-pressure cylinder is fully closed, and the second pressure regulating valve 631 on the extraction branch 63 of the low-pressure cylinder is opened; the exhaust steam of the small steam turbine 5 is connected to the extraction port of the low-pressure last-stage low-pressure heater and enters the low-pressure cylinder 2. Among them, when the first pressure regulating valve 621 and the second pressure regulating valve 631 are opened, the opening degree can be adjusted according to the situation, so as to adjust the steam volume passing through the valve.
[0033] The small steam turbine 5 is designed as a high back-pressure unit with regenerative extraction. The exhaust steam of the small steam turbine 5 is used as the steam source for cooling the main low-pressure cylinder 2, and there is no need to set up a separate cooling bypass; the high back-pressure exhaust steam of the small steam turbine 5 and the design pipe diameter are greatly reduced compared with the conventional exhaust condenser, and the layout is easy. The whole system is simple and efficient, increasing the heating capacity or peak shaving depth of the unit.
[0034] The technical solutions provided by the embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to help understand the principles of the embodiments of the present invention; at the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.
Claims
1. A steam turbine intermediate exhaust industrial heating system for a new power system, comprising an intermediate pressure cylinder, a low pressure cylinder, and a connecting pipe connecting the exhaust port of the intermediate pressure cylinder and the steam inlet of the low pressure cylinder, characterized in that: The steam extraction port of the medium pressure cylinder is connected in parallel to the deaerator and the low pressure heat recovery system through a steam extraction pipeline; The connecting pipe is provided with a first butterfly valve and a second butterfly valve respectively near the steam exhaust port of the intermediate pressure cylinder and the steam inlet port of the low pressure cylinder; The steam inlet of the small steam turbine of the low-pressure heat recovery system is connected to the first steam extraction branch of the steam extraction pipeline, and a steam inlet regulating valve is provided on the first steam extraction branch; the exhaust port of the small steam turbine is connected in parallel to one end of the connecting pipe close to the steam inlet of the low-pressure cylinder and the low-pressure last-stage low-pressure exhaust port of the low-pressure cylinder through the exhaust pipeline.
2. The steam turbine middle exhaust industrial heating system for a new power system according to claim 1 is characterized in that: The low-pressure heat recovery system also includes a first low-pressure heater and a second low-pressure heater respectively connected to the first steam extraction port and the second steam extraction port of the small steam turbine through branch pipes; one end of the condensate heating pipeline is connected to the shaft seal heater outlet, and the other end is connected to the water inlet of the deaerator; the condensate heating pipeline between the shaft seal heater and the deaerator is connected in series with the first low-pressure heater and the second low-pressure heater.
3. The steam turbine middle exhaust industrial heating system for a new power system according to claim 2 is characterized in that: The first condensate outlet of the first low-pressure heater is connected to the second low-pressure heater through a first condensate pipeline, and the second condensate outlet of the second low-pressure heater is connected to the condensate heating pipeline between the first low-pressure heater and the second low-pressure heater through a second condensate pipeline.
4. The steam turbine middle row industrial heating system for a new power system according to claim 2 is characterized in that: The number of the low-pressure heater stages is set to 2, 3 or 4 according to specific circumstances.
5. The steam turbine middle exhaust industrial heating system for a new power system according to claim 1 is characterized in that: The low-pressure heat recovery system also includes a feed water pump connected to one end of the rotating shaft of the small steam turbine, and the other end of the rotating shaft away from the feed water pump is connected to a constant speed generator / motor.
6. The steam turbine middle exhaust industrial heating system for a new power system according to claim 5, characterized in that: A speed regulating device is also provided between the constant speed generator / motor and the rotating shaft, one end of the speed regulating device is connected to the constant speed generator / motor, and the other end thereof is connected to the rotating shaft.
7. The steam turbine middle exhaust industrial heating system for a new power system according to claim 1, characterized in that: The exhaust steam pipeline includes an exhaust steam main pipeline and a A low-pressure cylinder steam inlet branch and a low-pressure cylinder steam extraction branch; one end of the low-pressure cylinder steam inlet branch is connected to the exhaust main line, and the other end is connected to the connecting pipe near the end of the low-pressure cylinder steam inlet; one end of the low-pressure cylinder steam extraction branch is connected to the exhaust main line, and the other end is connected to the conventional low-pressure final stage low-pressure exhaust port; the low-pressure cylinder steam inlet branch and the low-pressure cylinder steam extraction branch are respectively provided with a first pressure regulating valve and a second pressure regulating valve.
8. The steam turbine middle exhaust industrial heating system for a new power system according to claim 1 is characterized in that: The first butterfly valve is a butterfly valve having a large passage in a fully closed state; the second butterfly valve is a butterfly valve having a smaller passage in a fully closed state.