Multi-channel water energy storage system for long-time peak regulation and rapid frequency modulation of thermal power generating unit

Abstract

A multi-channel water energy storage system for long-time peak regulation and rapid frequency modulation of a thermal power generating unit comprises a thermoelectric main machine system, a machine-boiler decoupling module and a water working medium heat storage system. The water working medium heat storage system comprises a heat absorption module, a heat storage module and a heat release module, and the water working medium energy storage system works in the two processes of heat storage and heat release; the heat absorption module is provided with two working medium water paths, and working medium water in the first heat absorption path and high-temperature steam led out by the thermoelectric host system are heated in a steam-water heat exchange mode and then stored; the working medium water in the second heat absorption path and part of high-temperature feed water led out of the boiler feed water system are heated in a water-water heat exchange mode and then stored; the turbine-boiler decoupling module comprises a steam ejector and an electric steam boiler, high-capacity heat supply / steam supply is provided during deep adjustment of a unit, a high-pressure bypass and a medium-pressure bypass which are generated through decoupling can be connected with a high-capacity energy storage system, and a low-investment, high-efficiency and high-capacity two-way peak regulation means is provided. And the coordination requirement between new energy development and power grid stability faced by the power grid is met.

Description

Technical Field

[0001] This invention belongs to the field of flexible peak shaving in thermal power plants, and is particularly suitable for large-scale thermal power plants. It meets the grid's demand for large-scale, long-term peak shaving. The system can smoothly achieve ultra-large capacity thermal storage, uses water as the energy storage medium, is simple to operate and maintain, has high cost-effectiveness, and wide adaptability, meeting the urgent needs of power generation carbon reduction, thermal power transformation, and new energy expansion. This invention relates to the field of peak shaving and energy storage technology for thermal power units, specifically to a multi-redundant, wide-range, bidirectional, and smoothly adjustable large-capacity energy storage system, aiming to improve the bidirectional peak shaving capability of thermal power units and meet the coordinated needs of grid stability and new energy development. Background Technology

[0002] Traditional thermal power generating units (especially combined heat and power units) exhibit significant thermoelectric coupling. With the rapid development of renewable energy (wind power, photovoltaic) and the continuous expansion of combined heat and power scale, the flexibility of heating units has become a major pain point in the industry. For thermal power plants, during the heating season, restrictions during deep regulation to ensure heating supply result in huge "coal / electricity inversion losses"; restrictions during peak hours reduce potential revenue; and during the non-heating season, deep regulation periods also require passive power generation based on the boiler's minimum stable combustion load, similarly incurring significant "coal / electricity inversion losses." For renewable energy, the inherent thermoelectric coupling and minimum stable combustion load of thermal power units, along with their large operating capacity and power generation base, become "meaningless ineffective power generation" during periods of high renewable energy generation, generating massive amounts of ineffective carbon emissions. For the power grid, thermal power plants are the ballast stone for grid security, but the accompanying costs are too high. Especially during the heating season, the significant reduction in flexibility makes grid dispatch extremely difficult, forcing a substantial reduction in the scale of green electricity fed into the grid, seriously hindering the development of the renewable energy industry, affecting the process of reducing carbon emissions in the power sector, and even threatening the safe operation of the power grid.

[0003] To address the flexibility issue of thermal power, existing mainstream technologies include electrochemical energy storage, electrically heated molten salt energy storage, high-voltage steam molten salt energy storage, or high-voltage steam combined with electrically heated molten salt energy storage, but all of them have the following limitations.

[0004] Using electrochemical energy storage results in a very large base energy volume when thermoelectrically coupled. Purely relying on the "storage" approach for deep regulation leads to excessively large investment scales. For example, a 2*300MW cogeneration unit, under rated steam extraction during severe cold periods, still generates more than 60% of its capacity during deep regulation. Based on a 6-hour duration for both units, this results in an ineffective energy output of up to 2160MWh. Therefore, cogeneration plants must first "decouple thermoelectricity" to reduce power generation and thus decrease the scale of energy storage. The disadvantages of using electrically heated molten salt energy storage are: the molten salt module system is complex; the electric heating method suffers significant cold-end losses during non-heating seasons / or heating seasons without cylinder shut-off, leading to low energy storage efficiency and reduced cost-effectiveness. It is suitable as a frequency regulation method but not as a large-capacity peak-shaving method. Molten salt modules also present challenges such as molten salt corrosion, difficulty in accidental salt removal, and a large workload for operation and maintenance. High-temperature steam-powered molten salt energy storage offers higher energy storage efficiency than electric heating under non-cylinder-cutting conditions. However, molten salt modules also suffer from pre-existing limitations. Furthermore, due to the greater thermal power of steam storage, a larger quantity of molten salt is required, resulting in higher investment costs compared to electric heating molten salt. In summary, molten salt modules offer the advantage of low high-temperature saturation pressure, but their system complexity leads to a large workload for operation and maintenance. The thermal power industry is still searching for an energy storage system that combines cost-effectiveness, ease of operation and maintenance, wide-range bidirectional peak shaving capability, and smooth operation. Summary of the Invention

[0005] To address the problems existing in the above-mentioned system, this invention proposes a new decoupling and energy storage solution. First, an electric steam boiler is introduced as one of the main decoupling methods, which can eliminate invalid grid-connected electricity and replace boiler startup, and the cold section steam flow regulation is smoother. At the same time, water is used as the energy storage medium, which is a single working medium, making operation and maintenance more convenient. In addition, high-pressure saturated water has a large heat storage capacity, low technical risk, good scalability of the heat storage module, and high cost performance.

[0006] A multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units includes a thermal power unit system, a boiler-turbine decoupling module, and a water-based thermal energy storage system; characterized in that: The main thermal power system includes the main steam pipeline, the high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, the low-pressure cylinder of the steam turbine, and the boiler reheater; The water-based thermal energy storage system includes a heat absorption module, a heat storage module, and a heat release module. The water-based thermal energy storage system operates in two processes: heat storage and heat release. The heat storage process is carried out by the heat absorption module and the heat storage module, and the heat release process is carried out by the heat storage module and the heat release module. The heat absorption module is configured with two working fluid water paths. In the first heat absorption path, the working fluid water is heated and stored after being heated by steam-water heat exchange with high-temperature steam drawn from the thermoelectric host system. In the second heat absorption path, the working fluid water is heated and stored after being heated by water-water heat exchange with a portion of high-temperature feedwater drawn from the boiler feedwater system. The boiler-turbine decoupling module includes a steam ejector. A portion of high-temperature, high-pressure main steam is drawn from the main steam pipeline via a branch and connected to the high-pressure inlet of the steam ejector. A portion of hot reheat steam is drawn from the intermediate-pressure bypass via a branch and enters the low-pressure inlet of the steam ejector. The exhaust outlet of the steam ejector is connected to the cold section inlet of the reheater.

[0007] Furthermore, in the first heat absorption path, some of the high-temperature feedwater and high-temperature steam drawn from the thermal power unit system are heated by steam-water heat exchange before entering the second heat absorption path to exchange heat with the working fluid water.

[0008] Furthermore, the first heat absorption path of the heat absorption module includes the energy storage #0 high-pressure heater, the energy storage hot section high-pressure heater, and the energy storage medium exhaust low-pressure heater; a high-pressure bypass is connected to the main steam pipeline, and part of the high-temperature and high-pressure main steam from the main steam pipeline is connected to the energy storage #0 high-pressure heater after passing through the high-pressure bypass; a medium-pressure bypass is connected to the medium-pressure cylinder inlet steam pipeline, and part of the reheat steam is connected to the energy storage hot section high-pressure heater after passing through the medium-pressure bypass; the exhaust steam diversion part of the medium-pressure cylinder is connected to the energy storage medium exhaust low-pressure heater through the low-pressure cylinder inlet steam bypass.

[0009] Furthermore, the second heat absorption path of the heat absorption module includes a feedwater heat exchanger and a condensate heat exchanger; the heat release module shares the feedwater heat exchanger and condensate heat exchanger in the second heat absorption path of the heat absorption module; the medium in the feedwater heat exchanger and condensate heat exchanger can switch bidirectional flow during the heat storage process and the heat release process, using a single pipe to switch the flow direction or using parallel double pipes.

[0010] Furthermore, the thermal storage module includes a high-pressure water storage tank and a non-pressurized water storage tank; the high-pressure water storage tank is connected to two streams of heated working water, one stream being the working water heated by the low-pressure heater in the energy storage middle section, the high-pressure heater in the energy storage hot section, and the high-pressure heater in the energy storage #0; the other stream is the working water heated by the condensate heat exchanger and the feedwater heat exchanger.

[0011] Furthermore, the pipeline of the #0 high-pressure heater for energy storage is equipped with two independent water-side channels, one for the energy storage working fluid and the other for the main feedwater.

[0012] Furthermore, the second heat absorption path is configured with two forms of high-temperature feedwater heat release; The first type is the gravity-flow heat release form. After being heated by the energy storage #0 high-temperature heater, the high-temperature feedwater enters the feedwater heat exchanger to release heat. After releasing heat, it is connected to the condensate heat exchanger to release heat, and finally enters the condensate pipeline. The part of the feedwater that participates in the heat release adopts the gravity flow method in the heat exchange loop. The second type is a cascaded heat release method. After being heated by the #0 high-temperature heater, the high-temperature feedwater enters the feedwater heat exchanger to release heat. After releasing heat, it is connected to the feedwater pipeline by the feedwater booster pump. The condensate diverted from the outlet of the #5 low-temperature heater enters the condensate heat exchanger to release heat and is then connected to the condensate pipeline by the condensate booster pump. The feedwater and condensate that participate in the heat release are released in a cascaded manner and are forced to circulate in the heat exchange loop.

[0013] Furthermore, the feedwater heat exchanger and the condensate heat exchanger are sequentially connected between the high-pressure water storage tank and the unpressurized water storage tank, and a pressure relief valve is installed on the connecting pipeline between the shell sides of the two.

[0014] Furthermore, the heat release module further includes a heating network water heat exchanger; a high-pressure water storage tank is connected in parallel to the heat release side inlet of the heating network water heat exchanger after passing through a feed water heat exchanger; and the heat release side outlet of the heating network water heat exchanger is connected to an unpressurized water storage tank.

[0015] Furthermore, the high-pressure water storage tank is connected to the high-pressure heater of energy storage #0 and / or the steam side of the adjacent high-pressure heater via a high-pressure steam side connecting pipe; the steam in the connecting pipe is designed for bidirectional flow. During the heat storage stage, the steam in the tank is discharged to a suitable low-pressure point through the connecting pipe, ensuring that the tank does not exceed the pressure limit; during the heat release stage, the high-pressure heater of energy storage #0 and / or the steam side of the adjacent high-pressure heater are charged into the storage tank through the connecting pipe, driving the working fluid water in the tank to flow.

[0016] Furthermore, the boiler-generator decoupling module also includes an electric steam boiler, which is connected to the plant's electrical system and uses electricity to produce steam during off-peak periods. The steam is then piped into the cold section of the unit's boiler.

[0017] Furthermore, the boiler-machine decoupling module also includes a one-to-one decoupling module, which sets up a one-to-one decoupling connecting pipe between the units to drive the synchronous decoupling of adjacent units. It is connected between the medium-pressure bypass of the active unit and the boiler cold section inlet of the passive unit.

[0018] Furthermore, the design pressure of the high-pressure water storage tank is selected in the range of 3~10MPa.

[0019] Furthermore, a minimum flow valve is installed in parallel with the shut-off valve on the high-pressure bypass. During the period when the steam ejector of the decoupled boiler and turbine is shut down, the minimum flow valve keeps the high-pressure bypass in a hot state.

[0020] Furthermore, the condensate drain of the #0 high-pressure heater is connected to the condensate drain side of the #1 high-pressure heater, the condensate drain of the hot section high-pressure heater is connected to the deaerator, and the condensate drain of the middle-discharge low-pressure heater is connected to the condensate drain side of the #5 low-pressure heater.

[0021] Furthermore, the high-pressure bypass can provide high-pressure steam to external users; the medium-pressure bypass can provide medium-pressure steam to external users or connect to the first station of the heating network.

[0022] Furthermore, the steam production of the electric steam boiler can be flexibly adjusted. When the ejector is not running, it can independently undertake the decoupling of the boiler and turbine. The steam is distributed and transported to the cold section of the reheater of multiple adjacent boilers, or it can be directly sent to the first station of the heating network, the auxiliary steam system, and the steam side of each high-pressure boiler.

[0023] The beneficial effects of this invention are: The purpose of this invention is to provide a large-capacity energy storage system with multiple redundancies, wide-range, bidirectional, and smooth adjustment. By decoupling the boiler and turbine and storing energy in working fluid water, it can achieve wide-range peak shaving of thermal power units, improve the operational flexibility and economy of the units, and meet the grid's requirements for the absorption and stability of new energy sources.

[0024] Integrating the electric boiler into the boiler-machine decoupling module enables zero-grid power consumption and significantly enhances primary frequency regulation capabilities, overcoming the drawbacks of simple ejector decoupling and simple electric boiler decoupling. The introduction of the electric boiler allows for zero-grid connection between this unit and adjacent units. Retaining the ejector reduces the amount of steam entering the intermediate-pressure cylinder during pure condensing operation, minimizing cold-end losses during deep-heating periods. Using water-based energy storage instead of molten salt allows for larger-capacity thermal storage; at the same cost, the thermal storage capacity of water-based storage is more than twice that of molten salt, resulting in a better cost-performance ratio. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system connections.

[0026] Figures 2-3 The two working modes of the thermal storage stage are shown.

[0027] Figure 4 The diagram shows a conventional exothermic operating mode.

[0028] In the diagram: Steam ejector (1), electric steam boiler (2), energy storage #0 high-pressure heater (3), energy storage hot section high-pressure heater (4), energy storage low-discharge low-pressure heater (5), feedwater heat exchanger (6), condensate heat exchanger (7), high-pressure water tank (8), unpressurized water tank (9), heating network water heat exchanger (10), cold water pump (11), condensate booster pump (12), feedwater booster pump (13), turbine high-pressure cylinder (HD), turbine intermediate-pressure cylinder (MD), turbine low-pressure cylinder (LD), high-pressure heater (#1GJ, #2GJ, #3GJ), low-pressure heater (#5DJ, #6DJ, #7DJ), deaerator (CY), valve (V, V0-V14, S0, H1, H2, H3, H4). Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0030] The technical solution of the present invention is not limited by the capacity of power plant units.

[0031] The technical solution of the present invention is not limited to whether the power plant unit is newly built or already in operation.

[0032] The technical solution of the present invention is not limited by the number of power plant units participating in deep thermoelectric decoupling and the number of heating units, nor by the destination of steam at each level after decoupling, and can be flexibly adjusted.

[0033] The technical solution of the present invention is not limited by the steam parameters of power plant units.

[0034] The technical solution of the present invention is not limited by the combined heat and power or pure condensing operation of power plant units.

[0035] The technical solution of this invention is not limited by the energy storage medium (water or heat transfer oil), energy storage heater, water storage tank, or other heat exchanger types, locations, or ejector equipment (or steam compressors, electric steam boilers, or other equivalent equipment). At the same time, the de-cooling and de-pressure device can also be other equipment, such as a small steam turbine for power generation with residual pressure (which can operate according to different working conditions, such as reducing plant power consumption or achieving peak power generation). It can also be an added thermal energy storage device, and is not affected by the form of heat storage and release, such as overall feedwater heat release or cascade heat release.

[0036] like Figure 1 As shown, no modifications are required to the boiler body and turbine body, all boiler auxiliary equipment does not need modification, and the tail flue does not require low-load modification. No modifications are needed to any rotating machinery on the turbine side. The regenerative system requires appropriate modifications to accommodate changes in feedwater volume. The turbine load rate can be set according to grid dispatch, and the boiler load can be determined based on the sum of electrical and thermal loads. During this process, the unit can smoothly transition from conventional extraction / condensing or heating mode to a completely decoupled boiler-turbine state.

[0037] Host system composition, such as Figure 1 As shown, the host system can be composed of multiple standalone systems.

[0038] Taking Unit #1 as an example, the single-unit system includes the main steam pipeline, the high-pressure cylinder (HD) of the turbine, and the boiler; the boiler contains a superheater and a reheater. The main steam pipeline of the power plant is connected to the high-pressure cylinder of the turbine. High-temperature and high-pressure main steam from the main steam pipeline enters the high-pressure cylinder of the turbine. The exhaust steam from the high-pressure cylinder enters the cold section inlet of the boiler reheater; the system also includes the intermediate-pressure cylinder (MD) of the turbine, the steam inlet and exhaust pipelines of the intermediate-pressure cylinder, and the low-pressure cylinder (LD) of the turbine. Hot reheat steam is introduced through the steam inlet pipeline of the intermediate-pressure cylinder. The hot section outlet of the boiler reheater is connected to the steam inlet pipeline of the intermediate-pressure cylinder. The hot reheat steam from the hot section outlet enters the intermediate-pressure cylinder of the turbine to perform work, and the steam after performing work enters the low-pressure cylinder of the turbine.

[0039] A high-pressure bypass is connected to the main steam pipeline. Valves and desuperheating and pressure reducing devices are installed on the high-pressure bypass. Part of the high-temperature and high-pressure main steam from the main steam pipeline is connected to the energy storage #0 high-pressure heater (3) in the energy storage system after passing through the high-pressure bypass. It can also provide high-pressure steam to the outside. The high-pressure bypass is further connected to the cold section inlet pipeline of the boiler reheater through a branch. Steam enters the cold section inlet of the boiler reheater after passing through valve V14 and desuperheating and pressure reducing device. A medium-pressure bypass is connected to the steam inlet pipeline of the medium-pressure cylinder. Valves and desuperheating and pressure reducing devices are installed on the medium-pressure bypass. Part of the hot reheat steam is connected to the high-pressure heater (4) in the energy storage hot section of the energy storage system after passing through the medium-pressure bypass. It can also provide medium-pressure steam to the outside or connect to the first station of the heating network. A low-pressure bypass is connected to the steam inlet pipeline of the low-pressure cylinder. Part of the steam can be connected to the low-pressure heater (5) in the energy storage system. It can also be used for heating. The remaining steam continues to enter the low-pressure cylinder to do work.

[0040] like Figure 1 As shown, the same system configuration can be used for other single-unit systems, namely, setting up high-pressure bypass, medium-pressure bypass, and low-pressure bypass for connecting to the energy storage system or for external steam and heat supply. The high-pressure bypass, medium-pressure bypass, and low-pressure bypass of each single-unit system can be uniformly connected to the main pipeline system for unified output, or they can be output separately using independent pipelines.

[0041] Furthermore, by setting up a boiler-turbine decoupling module and a water-based cascade energy storage system in the unit, peak shaving for thermal power units was achieved.

[0042] The boiler-machine decoupling module is built based on a steam ejector (1) as the core equipment. The ejector is connected to three steam lines: power steam, ejector steam, and exhaust steam. The power steam is the main steam generated by the boiler superheater. Part of it enters the high-pressure cylinder, and the other branch of the main steam serves as the power steam for the ejector. The ejector steam is the hot reheat steam generated by the boiler reheater. Part of the hot reheat steam enters the medium-pressure cylinder, and the split part of the hot reheat steam enters the ejector through hot reheat recirculation and is pressurized. After being pressurized by the ejector, the steam is discharged to the cold section of the boiler reheater and merges with the exhaust steam from the original high-pressure cylinder into the boiler. Each pipeline can be equipped with a matching de-heating and de-pressure device according to actual needs.

[0043] Taking Unit #1 as an example, a steam ejector (1) is added to Unit #1. A steam ejector (1) is connected between the cold section inlet and the hot section outlet of the boiler reheater. The steam ejector has a power steam inlet, an ejector steam inlet, and an exhaust outlet. A portion of high-temperature and high-pressure main steam is drawn from the main steam pipeline through a branch and connected to the power steam inlet of the steam ejector. A portion of reheat steam is drawn from the medium-pressure bypass through a branch and, after being desuperheated and depressurized, enters the ejector steam inlet of the steam ejector. The exhaust outlet of the steam ejector is connected to the cold section inlet of the reheater. A portion of the main steam, after being desuperheated and depressurized, enters the steam ejector as power steam, which is used to draw in a portion of the reheat steam introduced by the ejector inlet of the steam ejector. After the power steam and the portion of the reheat steam are mixed, they re-enter the cold section inlet of the reheater.

[0044] The steam ejector system can use a single or multiple steam ejectors. Multiple steam ejectors can be combined in series, parallel or series-parallel to form a steam ejector group, so as to adjust and optimize parameters such as the injection ratio and complete the variable operating conditions. The nozzles of the steam ejectors can be fixed nozzles or adjustable nozzles.

[0045] Because the boiler decoupling module ensures the safe flow of the boiler reheater, a large amount of main steam and hot reheat steam can be extracted. In this system, the main steam goes to the energy storage #0 high heater (3) via the high pressure bypass, and the hot reheat steam goes to the energy storage hot section high heater (4) via the medium pressure bypass or to the heat network heater after desuperheating and depressurization. The steam branching off the high pressure bypass can also enter the cold section of the boiler reheater via valve V14, desuperheating and depressurization device and the pipeline.

[0046] The shut-off valves on the high-pressure bypass are equipped with a minimum flow valve V0 in parallel. During the decoupling of the steam ejector from the boiler and turbine, the flow through the minimum flow valve V0 maintains the high-pressure bypass in a hot state. The extracted main steam and reheat steam can also be used for external steam supply, heating, or other forms of thermal storage during the off-peak season.

[0047] To facilitate coordination among multiple units, a decoupling auxiliary module is also provided for the boiler-turbine decoupling module. For example... Figure 1 As shown, the decoupling auxiliary module is used to drive the synchronous decoupling of adjacent units (i.e., a one-to-one decoupling module). It includes a one-to-one connecting pipe, which connects the medium-pressure bypass of Unit #1 (the active unit) and the boiler cold section inlet of the adjacent Unit #2 (the passive unit). After Unit #1 is equipped with the boiler-machine decoupling module to achieve boiler-machine decoupling, it can extract a large amount of hot resteam, which can be sent to the boiler cold section of Unit #2 through the pipeline where valve V1 is located (the decoupling connecting pipe). The safe flow rate of the boiler reheater of Unit #2 can also be guaranteed by using the hot resteam transported by the decoupling connecting pipe, and the decoupling down-peak regulation can be achieved synchronously. In addition, Unit #2 can also extract a large amount of main steam and hot resteam to the high-pressure heater of energy storage #0 and the high-pressure heater of energy storage hot section or the medium- and high-pressure steam supply, heating network heaters, etc.

[0048] Furthermore, the decoupling auxiliary module can also be achieved by setting up an electric steam boiler (2). The electric steam boiler is connected to the plant electrical system and consumes the generated electrical energy during the off-peak period. The electrical energy is used to produce suitable steam, which can be input into the cold section of the unit boiler through pipelines.

[0049] like Figure 1 As shown, the electric steam boiler (2) is connected to the cold sections of the boilers of Unit #1 and Unit #2 through pipelines. It can go to the cold section of the boiler of Unit #1 through the pipeline where valve V2 is located, and to the cold section of the boiler of Unit #2 through the pipeline where valve V3 is located. The supplementary steam from the electric steam boiler can also achieve the purpose of ensuring the safe flow of the reheaters of each unit. The steam production of the electric steam boiler can be flexibly adjusted and can completely or partially replace the boiler-machine decoupling module. When the ejector is not running, it can independently undertake the boiler-machine decoupling. The steam distribution to a single unit or two units can also be flexibly adjusted according to the needs. The steam is distributed and transported to the cold sections of the reheaters of multiple adjacent boilers, or directly to the first station of the heating network, the low-pressure heater in the energy storage, or the high-pressure heaters at all levels.

[0050] Both the steam ejector and the electric steam boiler jointly input steam into the cold section of the reheater, displacing the high-pressure bypass and achieving decoupling of the boiler and turbine. Simultaneously, to achieve decoupling of multiple units throughout the plant, a one-to-one decoupling interconnection pipe is configured, designating Unit #1 as the active unit. Its hot section steam, after being de-cooled, enters the cold section of the adjacent unit, achieving decoupling of the adjacent unit. This one-to-one decoupling method can be repeatedly extended to subsequent units; for example, the hot section steam of Unit #2 can continue to be supplied to the cold section of the reheater of Unit #3.

[0051] The water-based thermal energy storage system achieves decoupled heat storage and release. The system is designed in conjunction with the boiler feedwater system. The boiler feedwater system includes a condenser, condensate pumps, low-pressure heaters at various stages, a deaerator, feedwater pumps, and high-pressure heaters at various stages. Condensate from the condenser is pumped through the condensate pumps, low-pressure heaters, deaerator, feedwater pumps, and high-pressure heaters before being connected to the main boiler feedwater pipeline.

[0052] The water-based thermal energy storage system includes a high-pressure heater for energy storage #0 (3), a high-pressure heater for energy storage hot section (4), a low-pressure heater for energy storage low discharge (5), a feedwater heat exchanger (6), a condensate heat exchanger (7), a high-pressure water storage tank (8), a pressureless water storage tank (9), a heating network water heat exchanger (10), and a cold water pump (11). These components respectively constitute heat absorption modules, heat storage modules, and heat release modules. The water-based thermal energy storage system can operate in two processes: heat storage and heat release. The heat storage process is implemented by the heat absorption module and the heat storage module, while the heat release process is implemented by the heat storage module and the heat release module.

[0053] The heat absorption module includes the energy storage #0 high heater (3), the energy storage hot section high heater (4), and the energy storage low discharge low heater (5). The energy storage #0 high heater (3), the energy storage hot section high heater (4), and the energy storage low discharge low heater (5) are steam-water heat exchangers. Two pipelines are led out from the low-pressure water tank through the cold water pump and the pipelines where the front and rear valves are located. The first pipeline is connected to the energy storage low discharge low heater (5), the energy storage hot section high heater (4), and the energy storage #0 high heater (3) in sequence through valve V8. After absorbing heat, it is connected to the high-pressure water tank through the pipeline where the working fluid water energy storage valve H1 is located. The second pipeline enters the condensate heat exchanger (7), valve V13, feed water heat exchanger (6), and the pipeline where they are located after absorbing heat and entering the high-pressure water tank. The condensate heat exchanger (7) and the feed water heat exchanger (6) are water-to-water heat exchangers. Their shell side is the heat absorption side, and their tube side is the heat release side.

[0054] The steam side of the energy storage #0 high-pressure heater (3) is connected to the high-pressure bypass of the main unit system, the steam side of the energy storage hot section high-pressure heater (4) is connected to the medium-pressure bypass of the main unit system, and the steam side of the energy storage low-pressure exhaust heater (5) is connected to the low-pressure cylinder inlet steam bypass. The working fluid water in the unpressurized water tank undergoes heat exchange through two pipelines: the first pipeline uses a steam-water heat exchange method, and the second pipeline uses a water-water heat exchange method. After absorbing heat and increasing its temperature, the working fluid water flows into the high-pressure water tank for storage.

[0055] In addition, during the heat absorption process, the working fluid water in the second path absorbs heat through the pipelines where the condensate heat exchanger and feedwater heat exchanger are located. This heat absorption process involves different heat sources, and the heat sources are divided into two operating modes.

[0056] The first heat source is gravity-flow heat release. The feedwater from the outlet of the #1 high-pressure heater is diverted and heated by the H2 feedwater storage valve and the #0 high-pressure heater. Then, it enters the feedwater heat exchanger (6) through the H3 feedwater heat exchanger inlet valve to release heat. After releasing heat, it continues to enter the condensate heat exchanger (7) through the H4 feedwater heat exchanger outlet valve to release heat. Finally, it enters the condensate pipeline through the condensate booster pump (12). The heat source comes from the high-pressure heater. The feedwater that participates in the heat release adopts gravity flow in the heat exchange loop, which is suitable for conventional heat exchange efficiency. Since part of the feedwater is repeatedly circulated, the feedwater pump needs to increase its output power.

[0057] Figure 2 Thermal storage type 1 (gravity flow operation): During the above-mentioned thermal storage, the flow paths of each working fluid are as follows: Figure 2 The thermal parameters are calculated based on a 350MW unit.

[0058] 1. Energy storage working fluid water: It comes out of the unpressurized water storage tank and is divided into two paths, A and B; path A enters the condensate heat exchanger; path B enters the energy storage exhaust heater. Paths A and B can be operated separately or put into operation together.

[0059] 2. Feedwater A1 Line: At this time, the boiler is at 75% load, with a main feedwater flow rate of 728 t / h. The feedwater pump is operating at a TMCR flow rate of 1047 t / h. The excess 319 tons is drawn downstream from the #1 high-pressure heater and enters the No. 0 energy storage heater. After being heated, it serves as a heat source, flowing through the feedwater heat exchanger and condensate heat exchanger before returning to the condensate pump outlet. This line is gravity-fed, but the power consumption of the feedwater pump is increased.

[0060] The second heat source is a cascaded heat release form. The feedwater from the outlet of the #1 high-pressure heater is diverted, heated by the H2 feedwater storage valve and the #0 high-pressure heater, and then enters the feedwater heat exchanger (6) through the H3 feedwater heat exchanger inlet valve to release heat. After heat release, it is connected to the feedwater pipeline through the feedwater booster pump (5) and the pipeline where valve V5 is located. The heat released in the condensate heat exchanger comes from the condensate heat diverted by the #5 low-pressure heater. It enters the condensate heat exchanger through valve V6 to release heat, and then is connected to the condensate pipeline through the condensate booster pump (6) and valve V7. The heat sources come from the high-pressure heater and the low-pressure heater, forming a cascaded heat release of heat sources at different temperatures. The booster pump is used for forced circulation, which is suitable for enhancing heat exchange efficiency, while the output power of the feedwater pump remains unchanged.

[0061] Figure 3 Thermal storage type 2 (cascade operation): Water supply line A2: The water supply pump continues to operate at 728t. After passing through the water supply heat exchanger, the water flows along the A2 route and returns to the water supply pump outlet via the water supply booster pump (5). The power of the water supply pump does not increase.

[0062] Condensate A3 line: Condensate is drawn from the outlet of #5 low heater, flows through the condensate heat exchanger and then returns to the outlet of the condensate pump via the condensate booster pump (6) along the A3 line.

[0063] During this process, after being heated by the energy storage #0 high heater (3), the high-temperature feedwater can also be directly fed into the main feedwater pipeline of the boiler through valve V. When the turbine is under low load, the feedwater temperature can be increased, thereby increasing the flue gas temperature at the tail of the boiler.

[0064] The tube side of the energy storage #0 high-pressure heater (3) is equipped with two independent water-side channels, one for the energy storage working fluid water and the other for the main feedwater. The energy storage #0 high-pressure heater (3) can also be set up as two dedicated heaters, namely, a dedicated energy storage high-pressure heater and a feedwater heating high-pressure heater, which are respectively connected to the energy storage working fluid water and the main feedwater. The drain of the energy storage #0 high-pressure heater (3) is connected to the drain side of the #1 high-pressure heater, the drain of the energy storage hot section high-pressure heater (4) is connected to the deaerator (CY), and the drain of the energy storage low-discharge low-pressure heater (5) is connected to the drain side of the #5 low-pressure heater.

[0065] The thermal storage process operates during peak shaving periods when the boiler and turbine are decoupled or during periods of low spot electricity prices. The two high-quality steam streams generated after the boiler and turbine decoupling of Unit #1—the main steam from the high-pressure bypass and the reheat steam from the medium-pressure bypass—enter the designated high-pressure heater (3) and the high-pressure heater (4) of the thermal storage section, respectively, to heat the working fluid water. Additionally, the steam from the low-pressure cylinder inlet bypass can also enter the low-pressure exhaust heater (5) of the storage section to heat the working fluid water. The heated steam becomes condensate and enters the condensate side of the high-pressure heater (#1), the deaerator, and the condensate side of the low-pressure heater (#5), respectively.

[0066] The thermal energy storage module includes a high-pressure water storage tank (8) and a low-pressure water storage tank (9). As mentioned above, the high-pressure water storage tank (8) is connected to the energy storage working fluid water that has been heated by the energy storage #0 high-pressure heater (3), the energy storage hot section high-pressure heater (4), and the energy storage low-discharge low-pressure heater (5). The high-pressure water storage tank (8) is also connected to the energy storage #0 high-pressure heater (3) and #1 high-pressure heater through a high-pressure steam side connecting pipe.

[0067] When the heated working fluid water enters the high-pressure water storage tank, the remaining steam in the high-pressure water storage tank needs to enter the nearest high-pressure heater steam side through the steam side connecting pipe, such as the steam side of the energy storage #0 high-pressure heater (3) and #1 high-pressure heater.

[0068] The steam in the connecting pipe is designed for bidirectional flow. During the heat storage stage, as high-temperature saturated water enters the tank, the steam in the tank is discharged to a suitable low-pressure point through the connecting pipe, such as the steam side of the #0 high-pressure heater (3) and #1 high-pressure heater, ensuring that the tank does not exceed the pressure limit. During the heat release stage, pressurized steam is introduced into the storage tank from the steam side of the high-pressure heater through the connecting pipe, driving the working fluid water in the tank to flow out (the high-pressure water storage tank is a pressurized water storage tank and does not have a water pump). A pressure regulating valve (S0) is installed on the connecting pipe to make the pressure of the tank and each extraction steam side compatible. The heat storage working fluid water can be injected into the unpressurized water storage tank (9) in advance.

[0069] The heat release module includes a feedwater heat exchanger (6) and a condensate heat exchanger (7), both of which are water-to-water heat exchangers. The shell side is the heat release side, and the tube side is the heat absorption side. The shell sides of the feedwater heat exchanger (6) and the condensate heat exchanger (7) are sequentially connected between the high-pressure water storage tank and the unpressurized water storage tank.

[0070] The heat release module shares the feedwater heat exchanger and condensate heat exchanger in the second heat absorption path of the heat absorption module. On the heat release side, the high-pressure water storage tank is connected to the heat release side inlet of the feedwater heat exchanger through the pipeline where valve V11 is located; the heat release side outlet of the feedwater heat exchanger is connected to the heat release side inlet of the condensate heat exchanger through the pipeline where valve V13 is located; the heat release side outlet of the condensate heat exchanger is connected to the unpressurized water storage tank through valves V9, V10 and the cold water pump bypass.

[0071] After flowing out of the feedwater heat exchanger, it enters the condensate heat exchanger through valve V13 for a second heat exchange. The pressure is regulated by the pressure-regulating valve V13 to keep the shell-side pressure of the downstream condensate heat exchanger low, which can reduce the cost of the condensate heat exchanger and the shell-side operating pressure.

[0072] On the heat absorption side, the outlet branch of the condensate pump is connected to the heat absorption inlet of the condensate heat exchanger via the branch containing valve V7, and the heat absorption outlet of the condensate heat exchanger is connected to the deaerator via the branch containing valve V6; the outlet branch of the feedwater pump is connected to the heat absorption inlet of the feedwater heat exchanger via the branch containing valve V5, and the heat absorption outlet of the feedwater heat exchanger is connected to the boiler main feedwater pipeline via the pipeline containing valve V4.

[0073] The heat release module may further include a heat exchanger for a heating network (10). On the heat release side, the outlet of the feedwater heat exchanger can be connected to the heat release side inlet of the heat exchanger via the branch pipe where valve V12 is located. The heat release side outlet of the heat exchanger is connected to a pressureless storage tank via a bypass of a cold water pump. On the heat absorption side, the water from the heating network is connected to the heat absorption side, and after absorbing heat and increasing its temperature, it is returned to the heating network as heating network supply water. The cooled working fluid water can enter the pressureless storage tank for the next heat storage cycle stage.

[0074] The heat release process operates during peak shaving or periods of high spot electricity prices. Open valve S0 on the steam-side connecting pipe connected to the high-pressure water tank (8), and the high-pressure steam side charges the high-pressure water tank (8) with steam through the connecting pipe, which drives the working water in the high-pressure water tank to go to the feedwater heat exchanger (6), condensate heat exchanger (7) or heating network water heater (10) to release heat through valve V11 and the pipeline. The cooled working water can enter the unpressurized water tank through the cold water pump bypass to enter the next heat storage cycle stage. Specifically, when heat is released, such as Figure 4 As shown, the heat storage working fluid in the high-pressure water storage tank (8) enters the feedwater heat exchanger (6) through valve V11 and the pipeline thereon to release heat and heat the feedwater. The feedwater comes from the main system feedwater branch, enters the feedwater heat exchanger (6) through valve V5 after the feedwater pump, is heated, and then merges into the main feedwater pipeline through valve V4. After completing the first stage of heat exchange, the energy storage working fluid continues to enter the condensate heat exchanger (9) through valve V13 to heat the condensate. The condensate comes from the main system condensate branch, enters the condensate heat exchanger (9) through valve V7 after the condensate pump, is heated, and then merges into the pipeline before the deaerator through valve V6. After completing the first stage of heat exchange, the energy storage working fluid can also be connected to the heating network water heater (12) through V12 to heat the heating network water. After completing the second stage of heat release, the working fluid enters the unpressurized water storage tank through the cold water pump bypass to continue the next cycle.

[0075] The design pressure of a high-pressure water storage tank can be selected in the range of 3 to 10 MPa. In order to reduce the cost of the pressure vessel, a lower pressure can be selected, but the energy storage efficiency will also decrease accordingly. If you want to improve the energy storage efficiency, the high-pressure water storage tank should be selected according to the higher pressure value.

[0076] During energy storage and heat release, the condensate, feedwater, and heating network water can be heated by the energy storage medium, reducing the corresponding steam extraction and increasing the unit's power generation capacity. Together, these factors allow the system to return to full power generation. Furthermore, the unit itself and adjacent units in the main system (multi-unit system) can also increase their power generation capacity and return to full power generation.

[0077] The feedwater heat exchanger (6) and the condensate heat exchanger (7) are sequentially connected between the high-pressure water storage tank and the unpressurized water storage tank. The feedwater heat exchanger (6) and the condensate heat exchanger (7) are shared by the heat absorption module and the heat release module. The medium in the shell side and tube side of the feedwater heat exchanger and the condensate heat exchanger needs to switch the flow direction during the heat storage process and the heat release process. For example, the tube side pipeline connected to valve H3, feedwater heat exchanger and valve V5, the tube side pipeline connected to valve V6, condensate heat exchanger and valve V7, and the shell side line connected to the high-pressure water storage tank and the unpressurized water storage tank can be used to achieve bidirectional flow by setting a single pipe to switch the flow direction or by setting a bypass pipeline in parallel to achieve bidirectional flow.

[0078] In summary, the present invention has the following advantages: Wide-range peak-shaving capability: Through water-based thermal storage, combined with the decoupling of the boiler and turbine modules and the coordinated operation of different operating modules, multiple units can flexibly shave peaks within a wide range, which can better adapt to changes in grid load and meet the grid stability requirements after the integration of new energy sources. Two-way flexible operation: After the modules are stacked, they have the function of two-way flexible operation for peak shaving. When the grid load is high, the stored heat can be released to increase power generation; when the grid load is low, energy storage can be carried out to improve the flexibility and adaptability of the unit operation. The primary frequency regulation function is powerful: during the energy storage period, the energy storage power can be quickly adjusted to achieve primary frequency regulation. During heat release, the heat release power can be adjusted to achieve primary frequency regulation. Therefore, it has a powerful primary frequency regulation function in both storage and release periods. Moreover, water energy storage has a large heat storage capacity and a long operating time for storage and release, which can even be optimized to cover 24 hours a day, thus achieving full-day primary frequency regulation coverage.

[0079] Improved economic efficiency: It combines the unique large-capacity heating / steam supply function of decoupling boiler and turbine, and makes full use of the unit's energy through different operating conditions during the heating season and non-heating season, so as to maximize the revenue of thermal power plants at both ends of the peak and valley, regulate peak and frequency, reduce the losses caused by low electricity prices due to coal-fired power inversion, increase capacity price subsidies, reduce operating costs, and improve the economic efficiency of thermal power plants. Large-capacity energy storage: Transforms thermal power plants into low-investment, high-efficiency, and large-capacity rapid peak-shaving centers, effectively alleviating the contradiction between the development of new energy sources and grid stability, and promoting the consumption of new energy sources and the sustainable development of the grid. The above demonstrates the system's advantages in terms of structure, function, and operation. The application of the above-mentioned case system in this application can be replicated in other thermal power plants, and its operation is flexible. For example, after deep coupling adjustment, the turbine steam inlet method can be flexibly adjusted, and the steam inlet volume can also be varied under different operating conditions to meet various grid dispatching needs.

[0080] Finally, it should be noted that the above description is merely an explanation of the present invention and is not intended to limit the invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units, comprising a thermal power unit system, a boiler-turbine decoupling module, and a water-based thermal energy storage system; characterized in that: The main thermal power system includes the main steam pipeline, the high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, the low-pressure cylinder of the steam turbine, and the boiler reheater; The water-based thermal energy storage system includes a heat absorption module, a heat storage module, and a heat release module. The water-based thermal energy storage system operates in two processes: heat storage and heat release. The heat storage process is carried out by the heat absorption module and the heat storage module, and the heat release process is carried out by the heat storage module and the heat release module. The heat absorption module is configured with two working fluid water paths. In the first heat absorption path, the working fluid water is heated and stored after being heated by steam-water heat exchange with high-temperature steam drawn from the thermoelectric host system. In the second heat absorption path, the working fluid water is heated and stored after being heated by water-water heat exchange with a portion of high-temperature feedwater drawn from the boiler feedwater system. The boiler-turbine decoupling module includes a steam ejector. A portion of high-temperature, high-pressure main steam is drawn from the main steam pipeline via a branch and connected to the high-pressure inlet of the steam ejector. A portion of hot reheat steam is drawn from the intermediate-pressure bypass via a branch and enters the low-pressure inlet of the steam ejector. The exhaust outlet of the steam ejector is connected to the cold section inlet of the reheater.

2. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 1, characterized in that, In the first heat absorption path, some of the high-temperature feedwater and high-temperature steam drawn from the thermal power unit system are heated by steam-water heat exchange before entering the second heat absorption path to exchange heat with the working fluid water.

3. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 1, characterized in that, The first heat absorption path of the heat absorption module includes the energy storage #0 high-pressure heater, the energy storage hot section high-pressure heater, and the energy storage medium exhaust low-pressure heater; a high-pressure bypass is connected to the main steam pipeline, and part of the high-temperature and high-pressure main steam from the main steam pipeline is connected to the energy storage #0 high-pressure heater after passing through the high-pressure bypass; a medium-pressure bypass is connected to the medium-pressure cylinder inlet steam pipeline, and part of the reheat steam is connected to the energy storage hot section high-pressure heater after passing through the medium-pressure bypass; the exhaust steam diversion part of the medium-pressure cylinder is connected to the energy storage medium exhaust low-pressure heater through the low-pressure cylinder inlet steam bypass.

4. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 3, characterized in that, The second heat absorption path of the heat absorption module includes a feedwater heat exchanger and a condensate heat exchanger; the heat release module shares the feedwater heat exchanger and condensate heat exchanger in the second heat absorption path of the heat absorption module; the medium in the feedwater heat exchanger and condensate heat exchanger can switch bidirectional flow during the heat storage process and the heat release process, using a single pipe to switch the flow direction or using parallel double pipes.

5. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 4, characterized in that, The thermal storage module includes a high-pressure water storage tank and a non-pressurized water storage tank. The high-pressure water storage tank is connected to two heating working fluids. One is the energy storage working fluid that has been heated by the low-pressure heater in the energy storage middle section, the high-pressure heater in the energy storage hot section, and the high-pressure heater in the energy storage #0 section. The other is the energy storage working fluid that has been heated by the condensate heat exchanger and the feedwater heat exchanger.

6. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 3, characterized in that, The pipeline of the #0 high-pressure heater for energy storage is equipped with two independent water-side channels: one channel carries the energy storage working fluid water, and the other channel carries the main feedwater.

7. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 4, characterized in that, The second heat absorption path is configured with two high-temperature feedwater heat release methods; The first type is the gravity-flow heat release form. After being heated by the energy storage #0 high-temperature heater, the high-temperature feedwater enters the feedwater heat exchanger to release heat. After releasing heat, it is connected to the condensate heat exchanger to release heat, and finally enters the condensate pipeline. The part of the feedwater that participates in the heat release adopts the gravity flow method in the heat exchange loop. The second type is a cascaded heat release method. After being heated by the #0 high-temperature heater, the high-temperature feedwater enters the feedwater heat exchanger to release heat. After releasing heat, it is connected to the feedwater pipeline by the feedwater booster pump. The condensate diverted from the outlet of the #5 low-temperature heater enters the condensate heat exchanger to release heat and is then connected to the condensate pipeline by the condensate booster pump. The feedwater and condensate that participate in the heat release are released in a cascaded manner and are forced to circulate in the heat exchange loop.

8. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 5, characterized in that, The feedwater heat exchanger and the condensate heat exchanger are sequentially connected between the high-pressure water storage tank and the unpressurized water storage tank, and a pressure relief valve is installed on the connecting pipeline between the shell sides of the two.

9. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 8, characterized in that, The heat release module further includes a heating network water heat exchanger; a high-pressure water storage tank is connected in parallel to the heat release side inlet of the heating network water heat exchanger after passing through a feed water heat exchanger; and the heat release side outlet of the heating network water heat exchanger is connected to an unpressurized water storage tank.

10. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 5, characterized in that, The high-pressure water storage tank is connected to the high-pressure heater of energy storage #0 and / or the steam side of the adjacent high-pressure heater via a high-pressure steam side connecting pipe. The steam in the connecting pipe is designed for bidirectional flow. During the heat storage stage, the steam in the tank is discharged to a suitable low-pressure point through the connecting pipe, ensuring that the tank does not exceed the pressure limit. During the heat release stage, the high-pressure heater of energy storage #0 and / or the steam side of the adjacent high-pressure heater fill the storage tank with steam through the connecting pipe, driving the flow of the working fluid water in the tank.

11. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 1, characterized in that, The decoupling module for the boiler and turbine also includes an electric steam boiler, which is connected to the plant's electrical system. During off-peak periods, it uses electricity to produce steam, which is then piped into the cold section of the boiler.

12. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 1, characterized in that, The boiler-turbine decoupling module also includes a one-to-one decoupling module, which sets up a one-to-one decoupling connecting pipe between the units to drive the synchronous decoupling of adjacent units. It is connected between the medium-pressure bypass of the active unit and the boiler cold section inlet of the passive unit.

13. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 5, characterized in that, The design pressure of the high-pressure water storage tank is selected in the range of 3~10MPa.

14. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 3, characterized in that, The shut-off valves on the high-pressure bypass are equipped with minimum flow valves in parallel. During the period when the steam ejector of the decoupled boiler and turbine is shut off, the minimum flow valves keep the high-pressure bypass in a hot state.

15. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 3, characterized in that, The condensate drain of the #0 high-pressure heater is connected to the condensate drain side of the #1 high-pressure heater, the condensate drain of the hot section high-pressure heater is connected to the deaerator, and the condensate drain of the medium-discharge low-pressure heater is connected to the condensate drain side of the #5 low-pressure heater.

16. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 3, characterized in that, The high-pressure bypass can provide high-pressure steam to external users; the medium-pressure bypass can provide medium-pressure steam to external users or connect to the first station of the heating network.

17. The multi-channel water energy storage system for long-term peak shaving and rapid frequency regulation of thermal power units according to claim 11, characterized in that, The steam production of the electric steam boiler can be flexibly adjusted. When the ejector is not running, it can independently undertake the decoupling of the boiler and turbine. The steam is distributed and transported to the cold section of the reheater of multiple adjacent boilers, or it can be directly sent to the first station of the heating network, the auxiliary steam system, and the steam side of each high-pressure boiler.

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