A combined heat and power frequency modulation system and method

Abstract

The application discloses a combined heat and power frequency modulation system and method, which comprises a boiler and a steam turbine, the exhaust end of the steam turbine is connected with the steam inlet of the boiler through a circulating pipeline, a steam condensing device, a deaerator and a regenerative heating device are sequentially arranged on the circulating pipeline, the system further comprises a plurality of heat supply assemblies connected with different steam extraction positions of the steam turbine, a plurality of steam extraction assemblies connected with different steam extraction positions of the steam turbine, a plurality of low-pressure steam extraction assemblies connected with low-pressure steam extraction ends of the steam turbine, and a plurality of heat storage frequency modulation devices connected with the steam extraction assemblies and the low-pressure steam extraction assemblies and connected to different levels of heat users, the heat storage frequency modulation devices are suitable for storing steam of the steam turbine and injecting the stored steam into low-pressure steam to supply the heat users. According to the operation requirement of the unit, the opening degree of the heat supply assembly and the heat storage frequency modulation device is changed to meet the heat supply requirement of different levels of heat users and maintain the stability of heat supply.

Description

Technical Field

[0001] This invention relates to the field of combined heat and power (CHP) unit technology, and specifically to a CHP frequency regulation system and method. Background Technology

[0002] Combined heat and power (CHP) refers to a power plant that both generates electricity and uses the steam produced by its turbine generators to supply heat to users. CHP units supply both electricity and heat to users, with the heat supply consisting of hot water and steam. While CHP units need to stably supply heat to users, the power grid also demands their participation in peak shaving and frequency regulation. Therefore, how to effectively improve the operational flexibility of CHP units while meeting the requirement of supplying steam to users has become a major research direction.

[0003] Currently, with the large-scale grid connection of new energy sources such as wind and hydropower, the proportion of new energy power generation is increasing. However, due to the significant fluctuations in the energy supply of new energy over time, it is currently impossible to effectively predict the daily production capacity of new energy. Therefore, the grid connection of new energy will cause fluctuations in the grid frequency, affecting the power supply quality. The grid side has put forward relevant requirements for thermal power units to participate in peak shaving and frequency regulation. However, due to their thermoelectric coupling characteristics, the frequency regulation capability of combined heat and power (CHP) units is limited, so it is urgent to improve the frequency regulation capability of CHP units.

[0004] Currently, changing the output power of a steam turbine is generally achieved by altering the steam flow rate that performs work within the turbine. However, changing the steam flow rate will alter the turbine exhaust flow, leading to changes in condensate volume and consequently, the amount of water entering the deaerator. This will cause fluctuations in the water level inside the deaerator, affecting its safe operation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the frequency regulation capability of existing cogeneration units is limited due to their thermoelectric coupling characteristics, thereby providing a cogeneration frequency regulation system and method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A combined heat and power frequency regulation system includes a boiler and a steam turbine. The exhaust end of the steam turbine is connected to the steam inlet of the boiler through a circulation pipeline. A steam condensation device, a deaerator, and a regenerative heating device are sequentially arranged on the circulation pipeline.

[0008] The system also includes:

[0009] Several heating components are connected to different steam extraction points of the steam turbine, making them suitable for direct heating to different levels of heat users;

[0010] Several steam extraction components are connected to different steam extraction locations of the steam turbine;

[0011] Several low-pressure extraction steam components are connected to the low-pressure extraction steam end of the steam turbine.

[0012] Several thermal storage frequency regulation devices are respectively connected to the steam extraction assembly and the low-pressure steam extraction assembly and connected to different levels of heat users; the thermal storage frequency regulation devices are suitable for storing turbine steam and injecting low-pressure steam to supply heat users with the stored steam.

[0013] The heating component further optimizes the technical solution and includes:

[0014] A medium-pressure heating assembly, comprising a medium-pressure heating pipe and a medium-pressure heating steam extraction valve disposed on the medium-pressure heating pipe, wherein the end of the medium-pressure heating pipe is connected to a medium-pressure heat user;

[0015] A low-pressure heating assembly, comprising a low-pressure heating pipe and a low-pressure heating steam extraction valve disposed on the low-pressure heating pipe, the end of the low-pressure heating pipe being connected to a low-pressure heat user.

[0016] The technical solution is further optimized, and the steam extraction assembly includes:

[0017] A high-pressure steam extraction assembly, comprising a high-pressure steam extraction pipe and a high-pressure thermal storage tank extraction valve disposed on the high-pressure steam extraction pipe;

[0018] A medium-pressure steam extraction assembly, comprising a medium-pressure steam extraction pipe and a medium-pressure thermal storage tank extraction valve disposed on the medium-pressure steam extraction pipe.

[0019] The technical solution is further optimized, and the thermal storage frequency regulation device includes:

[0020] The high-pressure thermal storage frequency regulation device is connected to the high-pressure steam extraction assembly at one end and to the medium-pressure heat user at the other end.

[0021] The medium-pressure thermal storage frequency regulation device is connected to the medium-pressure steam extraction assembly at one end and to the low-pressure heat user at the other end.

[0022] Further optimizing the technical solution, the high-voltage thermal storage frequency regulation device includes:

[0023] High-pressure thermal storage tank, suitable for storing high-pressure hot steam extracted by high-pressure steam extraction components;

[0024] The first steam ejector has a high-pressure steam port connected to a high-pressure thermal storage tank via a first steam output pipe, and an outlet connected to a medium-pressure heat user via a second steam output pipe. A middle low-pressure steam port is connected to a low-pressure extraction assembly. The first steam ejector uses high-pressure hot steam stored in the high-pressure thermal storage tank as its high-pressure steam source and low-pressure steam extracted by the low-pressure extraction assembly as its low-pressure steam source. The first steam ejector obtains medium-pressure steam by ejecting low-pressure steam from high-pressure steam and supplies it to the medium-pressure heat user.

[0025] The high-pressure thermal storage tank steam supply valve is installed on the first steam output pipe;

[0026] The outlet valve of the first steam ejector is located on the second steam output pipe.

[0027] Further optimizing the technical solution, the medium-pressure thermal storage frequency regulation device includes:

[0028] Medium-pressure thermal storage tank, suitable for storing medium-pressure hot steam extracted by medium-pressure steam extraction components;

[0029] The second steam ejector has a high-pressure steam port connected to the medium-pressure thermal storage tank via a third steam output pipe, and an outlet connected to the low-pressure heat user via a fourth steam output pipe. The middle low-pressure steam port is connected to the low-pressure extraction steam assembly. The second steam ejector uses the high-pressure hot steam stored in the medium-pressure thermal storage tank as its high-pressure steam source and the low-pressure steam extracted by the low-pressure extraction steam assembly as its low-pressure steam source. The second steam ejector extracts low-pressure steam from the medium-pressure steam to obtain low-pressure steam for supply to the low-pressure heat user.

[0030] The steam supply valve for the medium-pressure thermal storage tank is located on the third steam output pipe;

[0031] The outlet valve of the second steam ejector is located on the fourth steam output pipe.

[0032] The technical solution is further optimized, and the low-pressure steam extraction assembly includes:

[0033] The first low-pressure extraction steam assembly includes a first low-pressure extraction steam pipe and a first low-pressure extraction steam valve disposed on the first low-pressure extraction steam pipe.

[0034] The second low-pressure extraction steam assembly includes a second low-pressure extraction steam pipe and a second low-pressure extraction steam valve disposed on the second low-pressure extraction steam pipe.

[0035] A method for frequency regulation in cogeneration, wherein the method is performed using a cogeneration frequency regulation system, comprising the following steps:

[0036] S1. During unit operation, each thermal storage frequency regulation device stores steam;

[0037] S2. During the load increase process of the unit, the heating components are turned off to allow more steam to enter the turbine to do work, thus increasing the unit's power; at the same time, the thermal storage frequency regulation device is turned on to allow more of the stored steam to be injected into the low-pressure steam and supplied to heat users.

[0038] S3. During the load reduction process of the unit, the heating components are turned on to allow less steam to enter the turbine to do work, thus reducing the unit's power; at the same time, the thermal storage frequency regulation device is turned off to reduce the supply of stored steam to low-pressure steam to heat users.

[0039] To further optimize the technical solution, in steps S2 and S3, the low-pressure steam extraction flow rate is changed by adjusting the low-pressure steam extraction component to maintain a stable flow rate into the steam condensing unit, while simultaneously maintaining a stable water level in the deaerator.

[0040] The technical solution of this invention has the following advantages:

[0041] 1. The present invention provides a cogeneration frequency regulation system in which the steam source for different levels of heat users comes partly from the heating components and partly from the thermal storage frequency regulation device. Then, according to the unit's operating requirements, the heating needs of different levels of heat users are met by changing the opening degree of the heating components and the thermal storage frequency regulation device, thereby maintaining stable heating and ensuring that the frequency regulation capability of the cogeneration frequency regulation system is not limited.

[0042] 2. The present invention provides a cogeneration frequency regulation system, wherein the thermal storage frequency regulation device includes a high-pressure thermal storage frequency regulation device and a medium-pressure thermal storage frequency regulation device. The high-pressure thermal storage frequency regulation device and the medium-pressure thermal storage frequency regulation device are respectively equipped with thermal storage tanks and steam ejectors. According to the needs of heat users, the high-pressure thermal storage tanks and the medium-pressure thermal storage tanks are used as high-pressure steam sources for the steam ejectors to eject low-pressure steam, thereby realizing the cascade utilization of energy and improving energy utilization efficiency.

[0043] 3. The present invention provides a cogeneration frequency regulation system that adjusts the turbine load by regulating the steam extraction flow rate for heating, while using high- and medium-pressure heat storage tanks to ensure stable heating and stable deaerator water level.

[0044] 4. The present invention provides a cogeneration frequency regulation method, which changes the low-pressure extraction steam flow rate by adjusting the low-pressure extraction steam assembly and the thermal storage frequency regulation device, thereby maintaining a stable flow rate into the steam condensing unit and controlling the water level that finally flows into the deaerator. This enhances the unit's ability to participate in frequency regulation while maintaining a stable water level in the deaerator, ensuring the safe operation of the deaerator. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of a cogeneration frequency regulation system according to the present invention.

[0047] Figure label:

[0048] 1. Boiler; 2. Steam turbine; 3. Condenser; 4. Condensate pump; 5. Deaerator; 6. Feedwater pump; 7. High-pressure regenerative heater; 8. High-pressure thermal storage tank extraction valve; 9. Medium-pressure thermal storage tank extraction valve; 10. Medium-pressure heating extraction valve; 11. Low-pressure heating extraction valve; 12. First low-pressure extraction valve; 13. Second low-pressure extraction valve; 14. High-pressure thermal storage tank; 15. High-pressure thermal storage tank supply valve; 16. First steam ejector; 17. First steam ejector outlet valve; 18. Medium-pressure thermal storage tank; 19. Medium-pressure thermal storage tank supply valve; 20. Second steam ejector; 21. Second steam ejector outlet valve. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] Example 1

[0054] like Figure 1 A specific embodiment of a cogeneration frequency regulation system is shown, including a boiler 1, a steam turbine 2, a steam condensing device, a deaerator 5, a regenerative heating device, a heating assembly, a steam extraction assembly, a low-pressure steam extraction assembly, and a thermal storage frequency regulation device.

[0055] The exhaust end of the steam turbine 2 is connected to the steam inlet of the boiler 1 through a circulation pipeline. A steam condenser, a deaerator 5, and a regenerative heating device are installed sequentially on the circulation pipeline.

[0056] There are several heating components, which are connected to different steam extraction positions of the steam turbine 2, and are suitable for direct heating to heat users with different pressure requirements.

[0057] There are several extraction steam assemblies, which are connected to different extraction steam positions of turbine 2.

[0058] Several low-pressure extraction steam assemblies are provided, each connected to the low-pressure extraction steam end of the steam turbine 2.

[0059] Several thermal storage frequency regulation devices are installed, each connected to the extraction steam assembly and the low-pressure extraction steam assembly, and then connected to different levels of heat users. These devices are suitable for storing turbine steam and then injecting the stored steam into low-pressure steam to supply heat users.

[0060] 5. In the aforementioned combined heat and power frequency regulation system, the steam source for different levels of heat users partially comes from the heating components.

[0061] Another portion comes from the steam supply of the thermal storage frequency regulation device. Then, according to the unit's operating requirements, the opening size of the heating components and the thermal storage frequency regulation device is changed to meet the heating needs of different levels of heat users and maintain stable heating. At the same time, the low-pressure extraction steam flow rate is changed by adjusting the low-pressure extraction steam components and the thermal storage frequency regulation device to maintain a stable flow rate into the steam condensing unit, while also keeping the deaerator water level stable.

[0062] 0. As a specific implementation method, the steam condensation device includes a condenser 3 and a condensate pump 4. The condensate pump 4 is used to drive the condensed liquid to flow. The condenser 3 and the condensate pump 4 are existing conventional structures, and will not be described in detail here.

[0063] In one specific implementation, the regenerative heating device includes a feedwater pump 6 and a high-pressure regenerative heater 7. The high-pressure regenerative heater 7 is connected to the boiler and is used to heat the liquid, then input the heated medium into the boiler 1. The steam turbine has an extraction port in the middle, and a connecting pipeline connects the steam turbine and the high-pressure regenerative heater 7. This connecting pipeline indicates that steam is extracted from the steam turbine to heat the feedwater in the boiler 1 within the high-pressure regenerative heater 7, thus achieving multi-stage feedwater heating.

[0064] In one specific implementation, the heating assembly includes a medium-pressure heating assembly and a low-pressure heating assembly. The medium-pressure heating assembly includes a medium-pressure heating pipe and a medium-pressure heating extraction valve 10 installed on the medium-pressure heating pipe, with the end of the medium-pressure heating pipe connected to a medium-pressure heat user. The low-pressure heating assembly includes a low-pressure heating pipe and a low-pressure heating extraction valve 11 installed on the low-pressure heating pipe, with the end of the low-pressure heating pipe connected to a low-pressure heat user. In this embodiment, during unit operation regulation, the medium-pressure heating extraction valve 10 and the low-pressure heating extraction valve 11 can be directly adjusted to directly regulate the heating demand of different levels of heat users. Steam from the turbine is delivered to the medium-pressure heat user via the medium-pressure heating extraction valve 10 and to the low-pressure heat user via the low-pressure heating extraction valve 11.

[0065] It should be noted that the extraction steam port supplied from the steam turbine to the heat user is determined by the steam pressure required by the heat user, and does not refer to a specific extraction steam port.

[0066] In one specific implementation, the steam extraction assembly includes a high-pressure steam extraction assembly and a medium-pressure steam extraction assembly. The high-pressure steam extraction assembly includes a high-pressure steam extraction pipe and a high-pressure thermal storage tank steam extraction valve 8 installed on the high-pressure steam extraction pipe. The medium-pressure steam extraction assembly includes a medium-pressure steam extraction pipe and a medium-pressure thermal storage tank steam extraction valve 9 installed on the medium-pressure steam extraction pipe. In this embodiment, by adjusting the opening degree of the high-pressure thermal storage tank steam extraction valve 8 and the medium-pressure thermal storage tank steam extraction valve 9, the amount of steam extracted when supplying steam to the thermal storage frequency regulation device can be controlled.

[0067] In one specific implementation, the thermal energy storage frequency regulation device includes a high-pressure thermal energy storage frequency regulation device and a medium-pressure thermal energy storage frequency regulation device. One end of the high-pressure thermal energy storage frequency regulation device is connected to the high-pressure steam extraction assembly, and the other end is connected to the medium-pressure heat user. One end of the medium-pressure thermal energy storage frequency regulation device is connected to the medium-pressure steam extraction assembly, and the other end is connected to the low-pressure heat user.

[0068] The high-pressure thermal storage frequency regulation device includes a high-pressure thermal storage tank 14, a first steam ejector 16, a high-pressure thermal storage tank steam supply valve 15, and a first steam ejector outlet valve 17.

[0069] One end of the high-pressure heat storage tank 14 is connected to the high-pressure extraction pipe, and the high-pressure heat storage tank 14 is suitable for storing high-pressure hot steam extracted by the high-pressure extraction assembly.

[0070] The high-pressure steam port of the first steam ejector 16 is connected to the high-pressure heat storage tank 14 via the first steam output pipe, and the outlet is connected to the medium-pressure heat user via the second steam output pipe. The middle low-pressure steam port is connected to the low-pressure extraction...

[0071] The steam components are connected. The first steam ejector 16 uses the high-pressure hot steam stored in the high-pressure heat storage tank 14 as the high-pressure steam source and the low-pressure steam extracted by the low-pressure steam extraction component as the low-pressure steam source; the first steam ejector 16 obtains medium-pressure steam by ejecting low-pressure steam through high-pressure steam to supply medium-pressure heat users.

[0072] The high-pressure thermal storage tank steam supply valve 15 is installed on the first steam output pipe, which can control the amount of steam output from the first steam output pipe 0.

[0073] The first steam ejector outlet valve 17 is installed on the second steam output pipe and can control the amount of steam output from the second steam output pipe.

[0074] The medium-pressure thermal storage frequency regulation device includes a medium-pressure thermal storage tank 18, a second steam ejector 20, a steam supply valve for the medium-pressure thermal storage tank 19, and an outlet valve for the second steam ejector 21.

[0075] 5. One end of the medium-pressure heat storage tank 18 is connected to the medium-pressure extraction steam pipe, which is suitable for storing the medium-pressure hot steam extracted by the medium-pressure extraction steam assembly.

[0076] The high-pressure steam port of the second steam ejector 20 is connected to the medium-pressure heat storage tank 18 through the third steam output pipe, and the outlet is connected to the low-pressure heat user through the fourth steam output pipe. The middle low-pressure steam port is also connected to the low-pressure extraction...

[0077] The steam components are connected. The second steam ejector 20 uses the high-pressure hot steam stored in the medium-pressure heat storage tank 18 as the high-pressure steam source and the low-pressure steam extracted by the low-pressure steam extraction component as the low-pressure steam source; the second steam ejector 20 obtains low-pressure steam by ejecting low-pressure steam through medium-pressure steam and supplies it to low-pressure heat users.

[0078] The steam supply valve 19 of the medium-pressure thermal storage tank is installed on the third steam output pipe, which can control the amount of steam output from the third steam output pipe.

[0079] The second steam ejector outlet valve 21 is installed on the fourth steam output pipe and can control the amount of steam output from the fourth steam output pipe.

[0080] The aforementioned cogeneration frequency regulation system is equipped with a thermal storage tank as a thermal storage device, and simultaneously uses a steam ejector for frequency regulation and energy storage. Based on the needs of heat users, high-pressure and medium-pressure thermal storage tanks are used as high-pressure steam sources to eject low-pressure steam, achieving cascaded energy utilization and improving energy efficiency.

[0081] In one specific implementation, the low-pressure steam extraction assembly includes a first low-pressure steam extraction assembly and a second low-pressure steam extraction assembly. The first low-pressure steam extraction assembly includes a first low-pressure steam extraction pipe and a first low-pressure steam extraction valve 12 disposed on the first low-pressure steam extraction pipe. The second low-pressure steam extraction assembly includes a second low-pressure steam extraction pipe and a second low-pressure steam extraction valve 13 disposed on the second low-pressure steam extraction pipe. In this embodiment, the amount of low-pressure steam discharged can be adjusted by regulating the opening degree of the first low-pressure steam extraction valve 12 and the second low-pressure steam extraction valve 13, and the steam supply of the first steam ejector 16 and the second steam ejector 20 can also be adjusted, thereby meeting the functional requirements of different levels of heat users.

[0082] Example 2

[0083] This embodiment discloses a frequency regulation method for cogeneration, which is based on a cogeneration frequency regulation system and includes the following steps:

[0084] S1. During unit operation, each thermal storage frequency regulation device stores steam. That is, open the high-pressure thermal storage tank extraction valve 8 and the medium-pressure thermal storage tank extraction valve 9 to store steam in the high-pressure thermal storage tank 14 and the medium-pressure thermal storage tank 18 respectively, and then close the high-pressure thermal storage tank extraction valve 8 and the medium-pressure thermal storage tank extraction valve 9.

[0085] Steam enters the turbine 2 from boiler 1 to perform work. Steam users are divided into medium-pressure heat users and low-pressure heat users according to their demand pressure, and their steam supply is controlled by the medium-pressure heat supply extraction valve 10 and the low-pressure heat supply extraction valve 11, respectively. High-pressure steam is stored in high-pressure heat storage tank 14, and medium-pressure steam is stored in medium-pressure heat storage tank 18. The high-pressure steam source of the first steam ejector 16 is the high-pressure steam stored in the high-pressure heat storage tank 14, and the high-pressure steam source of the second steam ejector 20 is the medium-pressure steam stored in the medium-pressure heat storage tank 18. The low-pressure steam source is regulated by the turbine's first low-pressure extraction valve 12 and the second low-pressure extraction valve 13. The steam source for both medium-pressure and low-pressure heat users comes partly from the extraction steam from the turbine 2 and partly from the steam supply from the first steam ejector 16 and the second steam ejector 20.

[0086] S2. During the unit's load increase process, the heating components are partially closed, specifically the medium-pressure heating extraction valve 10 and the low-pressure heating extraction valve 11, to allow more steam to enter the turbine 2 to perform work, thus increasing the unit's power output. Simultaneously, the thermal storage frequency regulation device is fully opened, namely, the high-pressure thermal storage tank steam supply valve 15, the medium-pressure thermal storage tank steam supply valve 19, the first low-pressure extraction valve 12, the second low-pressure extraction valve 13, the first steam ejector outlet valve 17, and the second steam ejector outlet valve 21, so that more of the stored steam (i.e., high-pressure steam) is ejected from the low-pressure steam and supplied to heat users.

[0087] S3. During the unit load reduction process, the heating components are opened wider, specifically the medium-pressure heating extraction valve 10 and the low-pressure heating extraction valve 11, so that less steam enters the turbine 2 to do work, and the unit power decreases. At the same time, the thermal storage frequency regulation device is closed, that is, the high-pressure thermal storage tank steam supply valve 15, the medium-pressure thermal storage tank steam supply valve 19, the first low-pressure extraction valve 12, the second low-pressure extraction valve 13, the first steam ejector outlet valve 17 and the second steam ejector outlet valve 21 are closed, so that less of the stored steam is ejected to supply low-pressure steam to heat users.

[0088] During the adjustment process in steps S2 and S3 above, the heating supply to heat users remains stable.

[0089] The aforementioned cogeneration frequency regulation method integrates a thermal storage tank, a steam ejector, and the cogeneration unit. When the cogeneration unit participates in frequency regulation, it adjusts the steam supply to heat users, thereby indirectly regulating the amount of steam entering the turbine to perform work and changing the turbine's output power. This method affects the heating stability of heat users and causes changes in turbine exhaust steam, resulting in changes in condensate flow and consequently, changes in the flow rate into the deaerator, causing fluctuations in the deaerator water level. Therefore, this embodiment uses a steam ejector from the thermal storage tank to supply low-pressure steam to steam users, thus maintaining stable heating and a stable deaerator water level.

[0090] As a further improved implementation, in steps S2 and S3, since the amount of steam entering the turbine to do work changes, in order not to cause fluctuations in the condensate flow rate, the low-pressure extraction steam flow rate is changed accordingly by adjusting the low-pressure extraction steam assembly (i.e., adjusting the first low-pressure extraction steam valve 12 and the second low-pressure extraction steam valve 13) to maintain the stability of the flow rate entering the condenser, while maintaining the stability of the water level in the deaerator 5.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A cogeneration frequency regulation system, comprising a boiler (1) and a steam turbine (2), wherein the exhaust end of the steam turbine (2) is connected to the steam inlet of the boiler (1) through a circulation pipeline; wherein a steam condensation device, a deaerator (5) and a regenerative heating device are sequentially arranged on the circulation pipeline; Its features are, The system also includes: Several heating components are connected to different extraction positions of the steam turbine (2), which are suitable for providing direct heating to heat users of different levels; Several steam extraction components are connected to different steam extraction positions of the steam turbine (2); the steam extraction components include high-pressure steam extraction components and medium-pressure steam extraction components; Several low-pressure extraction steam components are respectively connected to the low-pressure extraction steam end of the steam turbine (2); Several thermal storage frequency regulation devices are respectively connected to the steam extraction assembly and the low-pressure steam extraction assembly and connected to heat users of different levels; the thermal storage frequency regulation devices are suitable for storing turbine steam and injecting low-pressure steam to supply heat users with the stored steam. The thermal storage frequency modulation device includes: The high-pressure thermal storage frequency regulation device is connected to the high-pressure steam extraction assembly at one end and to the medium-pressure heat user at the other end. The medium-pressure thermal storage frequency regulation device is connected at one end to the medium-pressure steam extraction assembly and at the other end to the low-pressure heat user. The high-voltage thermal storage frequency modulation device includes: High-pressure thermal storage tank (14) is suitable for storing high-pressure hot steam extracted by the high-pressure extraction assembly; The first steam ejector (16) has a high-pressure steam port connected to the high-pressure heat storage tank (14) through the first steam output pipe, and its outlet connected to the medium-pressure heat user through the second steam output pipe. The middle low-pressure steam port is connected to the low-pressure steam extraction assembly. The medium-pressure thermal storage frequency regulation device includes: Medium-pressure thermal storage tank (18) is suitable for storing medium-pressure thermal steam extracted by medium-pressure steam extraction assembly; The second steam ejector (20) has a high-pressure steam port connected to the medium-pressure heat storage tank (18) through the third steam output pipe, and its outlet connected to the low-pressure heat user through the fourth steam output pipe. The middle low-pressure steam port is connected to the low-pressure steam extraction assembly.

2. The cogeneration frequency regulation system according to claim 1, characterized in that, The heating components include: A medium-pressure heating assembly, comprising a medium-pressure heating pipe and a medium-pressure heating steam extraction valve (10) disposed on the medium-pressure heating pipe, wherein the end of the medium-pressure heating pipe is connected to a medium-pressure heat user; A low-pressure heating assembly, comprising a low-pressure heating pipe and a low-pressure heating steam extraction valve (11) disposed on the low-pressure heating pipe, the end of which is connected to a low-pressure heat user.

3. The cogeneration frequency regulation system according to claim 2, characterized in that, The high-pressure extraction steam assembly includes a high-pressure extraction steam pipe and a high-pressure heat storage tank extraction steam valve (8) installed on the high-pressure extraction steam pipe. The medium-pressure steam extraction assembly includes a medium-pressure steam extraction pipe and a medium-pressure heat storage tank extraction valve (9) installed on the medium-pressure steam extraction pipe.

4. A cogeneration frequency regulation system according to claim 3, characterized in that, The first steam ejector (16) uses the high-pressure hot steam stored in the high-pressure heat storage tank (14) as the high-pressure steam source and the low-pressure steam extracted by the low-pressure steam extraction assembly as the low-pressure steam source; the first steam ejector (16) obtains medium-pressure steam by ejecting low-pressure steam through high-pressure steam and supplies it to medium-pressure heat users; The high-voltage thermal storage frequency modulation device also includes: The high-pressure thermal storage tank steam supply valve (15) is installed on the first steam output pipe; The first steam ejector outlet valve (17) is installed on the second steam output pipe.

5. A cogeneration frequency regulation system according to claim 3, characterized in that, The second steam ejector (20) uses the high-pressure hot steam stored in the medium-pressure heat storage tank (18) as the high-pressure steam source and the low-pressure steam extracted by the low-pressure steam extraction assembly as the low-pressure steam source; the second steam ejector (20) obtains low-pressure steam by ejecting low-pressure steam through medium-pressure steam and supplies it to low-pressure heat users; The medium-pressure thermal storage frequency regulation device also includes: The steam supply valve (19) of the medium-pressure thermal storage tank is installed on the third steam output pipe; The second steam ejector outlet valve (21) is located on the fourth steam output pipe.

6. A cogeneration frequency regulation system according to claim 3, characterized in that, The low-pressure steam extraction assembly includes: The first low-pressure steam extraction assembly includes a first low-pressure steam extraction pipe and a first low-pressure steam extraction valve (12) disposed on the first low-pressure steam extraction pipe. The second low-pressure extraction steam assembly includes a second low-pressure extraction steam pipe and a second low-pressure extraction steam valve (13) disposed on the second low-pressure extraction steam pipe.

7. A method for frequency regulation in cogeneration, characterized in that, The method is based on a cogeneration frequency regulation system according to any one of claims 1 to 6, and includes the following steps: S1. During unit operation, each thermal storage frequency regulation device stores steam; S2. During the load increase process of the unit, the heating components are turned off to allow more steam to enter the turbine (2) to do work, and the unit power increases; at the same time, the heat storage frequency regulation device is turned on to store steam and inject low-pressure steam to supply more heat users. S3. During the load reduction process of the unit, the heating components are turned on to allow less steam to enter the turbine (2) to do work, and the unit power is reduced; at the same time, the heat storage frequency regulation device is turned off to reduce the supply of low-pressure steam to heat users.

8. A method for frequency regulation in cogeneration according to claim 7, characterized in that, In steps S2 and S3, the low-pressure steam extraction flow rate is changed by adjusting the low-pressure steam extraction component to maintain a stable flow rate into the steam condensing device, while maintaining a stable water level in the deaerator (5).

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