Thermal power side BDS multi-storage complementary system based on machine-furnace decoupling

Abstract

A thermal power side BDS multi-storage complementary system based on machine-furnace decoupling is provided with a thermal power machine-furnace decoupling module, a thermal energy storage module and an electric energy storage module. The fire engine-boiler decoupling module meets deep peak regulation after engine-boiler decoupling and can generate large-flow high-parameter quality steam; the heat energy storage module is connected into the boiler water supply system, and the decoupled high-parameter quality steam is connected into the heat energy storage module; the electric energy storage module and the kinetic energy storage module are accessed by plant power and / or network power; the machine-furnace decoupling system is superposed with fused salt energy storage, and the electric energy storage module and the kinetic energy storage module can be combined and applied to the thermal power plant and cooperate with each other to play a unique role, so that a multi-storage complementary long-time, high-efficiency and fast-response thermal power side energy storage system is provided for thermal power, the operation efficiency and stability of the thermal power plant are jointly improved, and the thermal power plant is protected. And the rapid scheduling requirement of the response power grid can be met.

Description

Technical Field

[0001] The utility model belongs to the field of flexible peak regulation of thermal power plants, can be used for multiple complementary energy storage applications, has the characteristics of shared energy storage and replacement of new energy storage, making thermal power a long-term, efficient and fast-response energy storage system, and specifically relates to a thermal power side BDS multi-storage complementary system based on machine-boiler decoupling. Background Art

[0002] With the rapid development of renewable energy, the power grid has an increasingly urgent need for energy storage systems. It is generally believed in the industry that molten salt energy storage, as a leader in thermal power storage technology, has attracted widespread attention for its long-term energy storage and efficient utilization. However, the physical properties of the molten salt energy storage system limit its application in shared energy storage and replacing new energy storage, such as requiring the energy storage system to have a rated peak function throughout the year. However, the molten salt energy storage system can only fully realize the peak function during the heating season. In the non-heating season, although the unit itself has the peak capacity, the heat release of the molten salt is limited by multiple factors such as steam turbine flow, unit back pressure, transformer capacity, and dispatching rules. And compared with electrochemical batteries, molten salt energy storage is difficult to meet the measurable, adjustable, and controllable requirements of power grid dispatch, and there is a significant lag in response time. Utility Model Content

[0003] The utility model aims to solve the above problems and provide a BDS multi-storage complementary system on the thermal power side based on boiler decoupling. The system combines the advantages of batteries and molten salt energy storage to achieve a perfect combination of rapid response to the power grid and long-term energy storage, while meeting the power grid's requirements for the construction and replacement of new energy storage.

[0004] A thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling, comprising a main steam pipeline, a steam turbine high-pressure cylinder, a steam turbine intermediate-pressure cylinder, and a boiler reheater; the main steam pipeline is connected to the steam turbine high-pressure cylinder, and the hot end outlet of the reheater is connected to the intermediate-pressure cylinder steam inlet pipeline; it is characterized in that it also has a thermal power boiler decoupling module, a thermal energy storage module, and an electrical energy storage module;

[0005] The thermal power boiler decoupling module is composed of a high-pressure steam bypass, a hot re-steam cycle bypass, and a steam ejector system; the main steam pipeline is connected with a high-pressure steam bypass, and the medium-pressure cylinder steam inlet pipeline is connected with a hot re-steam cycle bypass; the high-pressure steam bypass and the hot re-steam cycle bypass are connected to the steam ejector system to form a hot re-circulation, and the output of the steam ejector system is connected to the cold end inlet of the reheater;

[0006] A thermal energy storage module is connected to the boiler feed water system, and a high-pressure steam bypass and / or a hot re-steam cycle bypass is connected to the thermal energy storage module;

[0007] The electric energy storage module is connected to the factory power and / or grid power.

[0008] Furthermore, it also includes a small steam turbine module, and part of the steam in the unit is connected to the small steam turbine module as a driving steam source.

[0009] Furthermore, the thermal power boiler decoupling module is connected to the steam ejector system by a high-pressure steam bypass as power steam, and the hot re-steam cycle bypass is connected to the steam ejector system as suction steam, and the ejector outlet steam returns to the cold end inlet of the reheater.

[0010] Furthermore, the thermal energy storage module switches operation. When storing energy, steam is connected through the high-pressure steam bypass and / or the hot re-steam cycle bypass to heat the heat storage medium in the thermal energy storage module. When releasing energy, feed water is connected through the feed water bypass, and the heat storage medium releases heat to heat the boiler feed water to increase the temperature.

[0011] Furthermore, the thermal energy storage module outputs feed water which is further connected to the steam-water evaporation system, and outputs saturated steam into the main steam system or into the cold end of the reheater.

[0012] Furthermore, the electric energy storage module adopts a battery or a capacitor.

[0013] Furthermore, it also includes a kinetic energy storage module, and the factory power and / or grid power are connected to the kinetic energy storage module to perform mechanical energy storage and mutual conversion with electrical energy.

[0014] Furthermore, the small steam turbine module is provided with a small steam turbine cold end, and the small steam turbine cold end is also connected to the exhaust pipeline of the low-pressure cylinder of the steam turbine of the unit to realize interconnection with the cold end of the large unit.

[0015] Furthermore, the hot re-steam cycle bypass is connected to the small steam turbine module as a driving steam source.

[0016] Furthermore, the high-pressure steam bypass and the hot re-steam cycle bypass are connected to the outside to provide decoupled heating for the turbine and boiler; the medium-pressure cylinder exhaust pipe is connected to the outside to provide heating for the turbine and boiler side.

[0017] The beneficial effects of the utility model are:

[0018] The boiler-turbine decoupling system is superimposed on molten salt energy storage, as well as batteries and flywheel energy storage, and is applied in combination in thermal power plants. Each of them plays a unique role in coordination with each other, providing a long-term, efficient, and fast-response thermal power-side energy storage system with multiple storage complementarities, which jointly improves the operating efficiency and stability of thermal power plants and can meet the rapid dispatch needs of the power grid.

[0019] Among them: decoupling of turbine and boiler can achieve deep adjustment range of full load of boiler, minimum steam intake of steam turbine or coasting; decoupling of turbine and boiler can greatly reduce invalid electricity, thereby reducing losses, while reducing main steam and coal consumption; decoupling of turbine and boiler can obtain large flow high bypass steam, and after superimposing molten salt energy storage system, its efficiency can be increased to 91%, and there is no cold end loss in the heat storage link, ensuring efficient energy storage. And the unit cost is less than 400 yuan, building a large-scale molten salt energy storage industry chain on the thermal power side, and adapting to capacity electricity price subsidies.

[0020] Flywheel energy storage has the characteristics of high-frequency instantaneous precise discharge capability, high conversion efficiency, good safety, long service life, environmental friendliness and strong adaptability to the working environment. In thermal power plants, flywheel energy storage technology can quickly absorb or output active power, significantly alleviate the frequency regulation pressure of traditional frequency regulation units, avoid frequent unit operation, and thus improve the life, safety and stability of thermal power units. Its rapid response characteristics enable flywheels to quickly build frequency regulation power stations at any location in the power grid, further improving the frequency regulation capability of the power system.

[0021] The application of batteries in thermal power plants is mainly as energy storage devices, combined with flywheel energy storage and molten salt energy storage technology to form a multi-level energy storage system. Batteries can store excess electrical energy and release it when needed, balancing the supply and demand of the power system and improving the stability of the power grid.

[0022] In summary, the application of the BDS multi-storage complementary system on the thermal power side based on boiler-turbine decoupling in thermal power plants can significantly improve the operating efficiency, safety and stability of thermal power plants, promote the development of renewable energy, and make the power industry more environmentally friendly and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The following is a connection diagram of the system.

[0024] Figure 2 Schematic diagram of the energy storage system.

[0025] Figure 3 Schematic diagram of the energy release system.

[0026] Numbers in the figure: 1 reheater, 2 superheater, 3 high-pressure cylinder, 4 medium-pressure cylinder, 5 low-pressure cylinder, 6 large unit cold end, 7 steam ejector, 8 high-pressure heater, 9 deaerator, 10 low-pressure heater, 11 small unit cold end, 12 kinetic energy storage module, 13 electric energy storage module, 14 thermal energy storage module, 15 small steam turbine, 16 steam-water evaporation system, 17 unit external heating, 18 boiler decoupling external heating, 19 high-pressure steam bypass, 20 hot re-steam cycle bypass. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] The utility model is not limited by the size and type of the unit; and is not limited by the peak-shaving space.

[0029] The utility model is not limited by the specific parameters of various energy storages: no matter the power or the duration, there are no rigid regulations, and a customized design is required according to the specific conditions of the power plant and the requirements of the power grid.

[0030] The ratio between different energy storage systems of the utility model is not limited and can be optimized according to the actual project;

[0031] The utility model is not limited by the scale and method of molten salt heat storage, such as electric heating and steam heating. Electric heating is not limited by the type and model of the heater, high and low pressure, etc. The steam heating method is not limited by the main steam and hot re-steam described above, nor is it limited by the source of steam, which can be the local machine or the adjacent machine; the heat release mode is not limited by the heat source; it is not limited by molten salt as the heat storage and release medium, but can also be phase change heat storage, solid heat storage and other heat storage media; in addition, heat storage related equipment (such as molten salt tanks, etc.) is not limited by the number of specifications and models; related heat exchangers are not limited by the selection model and heat exchange form;

[0032] The utility model is not limited by the type, specification, model, and scale of the battery, and can also be a super capacitor, etc.;

[0033] The utility model small steam turbine is not limited by model specifications, such as pure condensation, back pressure; nor is it subject to the influence of steam source; nor is it subject to the power generation allocation, and can be plant power, local peak load regulation or temporary power;

[0034] The flywheel energy storage that satisfies the primary frequency modulation of the utility model may also be other forms of technical means, such as super capacitors, etc.;

[0035] The compatible control modules of each system of the utility model are not limited by their specifications and types.

[0036] Thermal power side BDS multi-storage complementary system based on turbine and boiler decoupling (Battery / battery, Decoupling of Turbine & Boiler / Turbine and boiler decoupling, Molten Salt Thermal Storage / molten salt thermal storage), including: thermal power boiler decoupling system (after decoupling, it can meet the needs of deep peak regulation and produce large-flow high-parameter quality steam), thermal energy storage (such as molten salt energy storage) system, small steam turbine and supporting cold end and corresponding grid-connected capacity expansion system, battery energy storage system, flywheel energy storage module, and related pipeline valve electrical control, etc., while the thermal system on the thermal power side remains unchanged. Through the above-mentioned module systems, the thermal power has the means to quickly respond to dispatch instructions (the role of the battery energy storage system), and uses molten salt as subsequent energy storage capacity, which can not only give play to the excellent dispatching and response characteristics of the battery, but also give play to the long-term and low-cost properties of molten salt; the small steam turbine, supporting cold end, and grid-connected capacity expansion are put into operation simultaneously. After the molten salt system is put into operation, the heat in the original thermal system is replaced, so that the system obtains an additional independent power generation function, which meets the grid's requirements for "new energy storage and replacement"; and the flywheel energy storage (kinetic energy storage) meets the needs of improving primary frequency regulation. The above system enables thermal power to meet the three elements of measurability, adjustability and controllability required by power grid dispatching, while improving response time; it has rated peak functionality throughout the year, can be used as "new energy storage replacement" capacity, and can also be used as "shared energy storage", making the thermal power system perfect in the new dual-carbon power system.

[0037] The newly added boiler-machine decoupling system and thermal energy storage (such as molten salt energy storage) system of the system are composed of: a newly built high-pressure bypass, a heat recirculation system with a steam ejector structure (the ejector power steam is the main steam provided by the newly built high-pressure bypass, and the induced hot resteam passes through the ejector), a thermal energy storage (such as molten salt energy storage) system, etc.; the boiler-machine decoupling system can realize large-flow and high-parameter heating / steam supply under deep peak regulation of thermal power, provide high-quality steam, and can also be used as a steam source for molten salt heat storage; and the thermal energy storage (such as molten salt energy storage) can be composed of but not limited to high-temperature molten salt tanks, low-temperature molten salt tanks, related molten salt pumps, temperature control pumps, salt mixers, electric heaters, control systems, safety devices, etc., and can also include other auxiliary equipment filters, insulation layers of heat storage tanks, and equipment for monitoring and maintaining the system. The molten salt system can return heat to the feed water system (part of the feed water flow diverted by the feed water pump is combined with the molten salt system heat exchanger at the outlet of the high pressure heater to enter the boiler), or it can enter the main steam system by making saturated steam (the access point is behind the steam drum or behind the steam-water separator) or generate cold-section steam for reheated steam. In this case, a new steam-water evaporation system is required: the main equipment includes but is not limited to superheaters, evaporators, preheaters, deaerators, start-up electric heaters, feed water pumps, etc.

[0038] The newly added small machine includes the small steam turbine body, the corresponding cooling system, the newly added control system, and other auxiliary systems (MOOG valve, main steam valve and regulating steam valve for oil system debugging, etc.). The small machine is used during peak hours, and the steam source comes from hot re-steam, or steam generated by the main steam and molten salt system. At the same time, the small machine is equipped with a cold end and power generation related systems;

[0039] The system's electrical energy storage can be composed of batteries: battery packs (consisting of multiple single cells for storing and releasing electrical energy), battery management systems (BMS), inverters (converting DC power into AC power in battery energy storage systems), energy management systems (EMS), temperature control systems, protection equipment, monitoring systems, other auxiliary equipment filters, isolation switches, etc.

[0040] The newly added kinetic energy storage system (such as flywheel energy storage) of this system consists of: flywheel (the flywheel is driven by an electric motor to rotate at high speed, thereby converting electrical energy into mechanical energy for storage), bearings, electric generators (in the charging stage, it operates as a motor to drive the flywheel to rotate faster; in the discharging stage, it operates as a generator to generate electrical energy using the energy of the flywheel rotation), power converters, vacuum chambers, and also includes some auxiliary equipment and control systems, such as cooling systems, monitoring systems, etc.

[0041] The utility model connects the battery and the molten salt energy storage system in parallel in an appropriate proportion, and uses the battery as a means of rapid response to the grid dispatching instructions to meet the grid's requirements for measurability, adjustability and controllability; at the same time, the molten salt is used as the subsequent energy storage capacity to give full play to its long-term and low-cost advantages. The system design not only improves the response speed of the system, but also ensures the durability of energy storage. In order to ensure the energy storage efficiency of the molten salt system, high-quality steam is required to heat the molten salt for heat storage, and the machine boiler system can just produce large-flow high-parameter steam in the deep adjustment stage of thermal power, which is just right for superposition with molten salt. The utility model proposes to enable the molten salt system to have an independent power generation function by means of building new small machines, adding cold ends, and increasing capacity online. In this way, in the non-heating season and heating season, the heat of the molten salt system replaces part of the heat of the original system, so that the small machine can effectively play the peak function and improve the system's annual utilization rate. The utility model also introduces a flywheel energy storage module. With its characteristics of rapid response and high power density, flywheel energy storage can provide a large amount of energy in a short time to meet the grid's rapid demand for frequency modulation.

[0042] A BDS multi-storage complementary system on the thermal power side based on boiler-turbine decoupling, the system consists of the following submodules:

[0043] 1. The boiler-turbine decoupling module (using steam ejector assembly for heating and recirculation) achieves the flow and velocity balance required by the boiler superheater and reheater;

[0044] 2. The thermal energy storage module realizes heat storage and heat release, which is used to increase the peak when storing heat and heat the water when releasing heat.

[0045] 3. Electric energy storage module, using electric energy storage as a means of rapid response to dispatch instructions.

[0046] Fourth, the kinetic energy storage module has the characteristics of fast response and high power density, which can provide a large amount of energy in a short time and meet the grid's rapid demand for frequency modulation.

[0047] 5. Small steam turbine modules play a peak function, improving the system's annual utilization rate and overall thermal power economy.

[0048] like Figure 1 The boiler and turbine bodies do not need to be modified, and the tail flue does not need to be modified for low load. All rotating machinery on the turbine side does not need to be modified. The turbine load rate can be set according to the grid dispatch, and the boiler load can be determined according to the sum of the electrical load and the thermal load. In this process, the unit can smoothly switch from the conventional extraction and condensation state to the complete decoupling state of the boiler and turbine.

[0049] The system includes a main steam pipeline, a steam turbine high-pressure cylinder 3, and a boiler reheater 1;

[0050] The boiler superheater 2 is connected to the high-pressure cylinder 3 of the steam turbine through the main steam pipeline of the power plant. The high-temperature and high-pressure main steam from the main steam pipeline enters the high-pressure cylinder 3 of the steam turbine. The exhaust steam of the high-pressure cylinder enters the cold end inlet of the boiler reheater 1;

[0051] The system also includes a steam turbine intermediate pressure cylinder 4 and an intermediate pressure cylinder steam inlet pipe.

[0052] The hot end outlet of the boiler reheater 1 is connected to the steam inlet pipe of the intermediate pressure cylinder. Part of the reheated steam at the hot section outlet enters the intermediate pressure cylinder 4 of the steam turbine to perform work.

[0053] A steam ejector 7 is connected between the cold section inlet and the hot section outlet of the boiler reheater 1 to form a heat-recycling system.

[0054] The intermediate pressure cylinder steam inlet pipe is connected to the hot re-steam cycle bypass 20, the hot section outlet of the reheater 1 is connected to the suction steam inlet of the steam ejector 7 through the hot re-steam cycle bypass 20, and the exhaust steam outlet of the steam ejector 7 is connected to the cold section inlet of the reheater 1. The main steam pipe is connected to the high-pressure steam bypass 19, and the high-pressure steam bypass 19 is connected to the power steam inlet of the steam ejector 7.

[0055] A temperature and pressure reducer (or other equipment with equivalent functions) may also be provided on the high-pressure steam bypass 19. Part of the main steam in the main steam pipeline enters the steam ejector 7 as motive steam after being cooled and reduced in pressure, and is used to extract part of the reheated steam connected to the steam suction inlet of the steam ejector 7. After part of the main steam is mixed with part of the reheated steam, it enters the cold section inlet of the reheater 1 again, thereby forming a heat recirculation.

[0056] The steam injector 7 can adopt a single or multiple steam injectors. A steam injector group is formed by connecting multiple steam injectors in series, parallel or series-parallel combination to achieve adjustment and optimization of parameters such as injection ratio and complete variable working conditions. The nozzle of the steam injector adopts a fixed nozzle or an adjustable nozzle.

[0057] The system further includes a thermal energy storage module 14 (molten salt energy storage module).

[0058] The molten salt energy storage module is composed of a heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank, etc. The heat exchanger adopts a shell and tube heat exchanger, and the two ends of the shell are respectively connected to the high-temperature molten salt tank and the low-temperature molten salt tank. The molten salt flows in the shell and exchanges heat with the heat medium introduced into the tube of the high-temperature heat exchanger and the low-temperature heat exchanger. The heat exchange is surface heating, and the molten salt exchanges heat with the steam or feed water introduced, and the low-temperature molten salt is heated by steam or the feed water is heated by high-temperature molten salt; the molten salt energy storage module is not limited to the above-mentioned structure, and the heat exchanger can also be in other forms.

[0059] Two groups of tube passes can be set in the heat exchanger. The first group of tube passes is used for passing steam. The high-pressure steam bypass is connected to the first group of tube passes. When storing energy and absorbing heat, part of the main steam in the high-pressure steam bypass enters the first group of tube passes after being cooled and reduced in pressure. The cooling and condensation releases heat to heat the molten salt medium in the shell. The cooling and condensation produce hydrophobicity that enters the hydrophobic system.

[0060] The second set of tubes is used for passing water medium and is connected to the feed water bypass. When releasing energy and heat, the boiler feed water flows through the second set of tubes, and heat is released through the high-temperature molten salt medium in the shell, which can heat the boiler feed water.

[0061] A feed water bypass is led out in front of the high pressure heater 8 in the boiler return water system, and the feed water bypass is connected to the inlet of the second group of pipe paths.

[0062] The second group of tube pass outlets are connected to the boiler return water system after the high-pressure heater 8 through pipelines.

[0063] Furthermore, the outlet of the second group of tube passes can also be connected to the steam-water evaporation system 16. After the feed water is heated by the high-temperature molten salt medium and enters the steam-water evaporation system 16, it is converted into saturated steam in the steam-water evaporation system 16. The saturated steam is connected to the main steam system, and the connection point is at the rear side of the boiler drum or the steam-water separator side, or the saturated steam is connected to the hot recirculation, and the connection point is at the entrance of the cold section of the reheater 1.

[0064] In another embodiment, the first group of tube passes and the second group of tube passes can be shared, using the same heat exchange component, and switching the working modes of different external pipelines to pass hot re-steam or boiler feed water.

[0065] The high-temperature molten salt tank may also be provided with a molten salt electric heater.

[0066] The system further includes an electric energy storage module 13, which is equipped with a battery with a scale of 90MW / 45MWh for storing electricity; at the same time, a kinetic energy storage module 12 (flywheel energy storage) is arranged in parallel: its motor operates as an electric motor, and the surplus electric energy of thermal power drives the motor to accelerate through the power electronic converter. As the motor rotates, the flywheel starts to accelerate. In this process, the electric energy is converted into mechanical energy and stored in the high-speed rotating flywheel. When the flywheel reaches the set maximum speed, the system enters the energy retention state, the flywheel rotates at a constant speed, and the stored energy is maintained.

[0067] The electric energy storage module 13 and the kinetic energy storage module 12 can be connected in parallel to the factory power grid (or in other forms).

[0068] The system further includes a small steam turbine 15 .

[0069] The hot re-steam circulation bypass 20 is connected to the steam inlet pipe of the medium-pressure cylinder. The hot re-steam circulation bypass 20 can be further connected to the small steam turbine 15. Part of the reheated steam can be used as the steam source of the small steam turbine 15 to drive the small steam turbine 15 to generate electricity. The hot re-steam circulation bypass is also connected to the high-pressure steam bypass. During the energy storage stage, the hot re-steam can also enter the heat exchanger of the molten salt energy storage module to heat the molten salt. The small steam turbine 15 is provided with a corresponding cold end 11 (water cooling or air cooling) to provide cooling function for the small steam turbine, and the small machine cold end 11 can also be interconnected with the large machine cold end 6. Through this interconnection method, the small machine cold end 11 can support the large machine to reduce the back pressure and improve the operating efficiency of the large machine.

[0070] Take the original system of a 300MW thermal power unit as an example:

[0071] The BDS multi-storage complementary system on the thermal power side based on boiler decoupling is adopted, which is operated and regulated based on power grid dispatching. The operation modes of the system in different periods are as follows:

[0072] 1) If Figure 2 As shown in the figure, the energy storage stage corresponds to the deep regulation period. When the grid dispatch demand is at a low point, the unit needs to generate as little power as possible.

[0073] 1-1) First, an electric energy storage system is deployed, with a battery capacity of 90MW / 45MWh to store electricity;

[0074] At the same time, the flywheel energy storage module is put into use: its motor operates as an electric motor, and the abundant electric energy of thermal power drives the motor to accelerate through the power electronic converter. As the motor drags the flywheel to start rotating faster, the electric energy is converted into mechanical energy and stored in the high-speed rotating flywheel. When the flywheel reaches the set maximum speed, the system enters the energy retention state, the flywheel rotates at a constant speed, and the stored energy is maintained. This process meets the grid's rapid demand for frequency modulation.

[0075] 1-2) Then the boiler-machine decoupling system is put into operation synchronously: the main steam generated by the boiler superheater passes through the high-pressure steam bypass (the boiler superheater generates main steam → high-pressure steam bypass → ejector power inlet) as the power steam of the ejector, and the hot resteam from the boiler reheater is ejected (the boiler reheater generates hot resteam → ejector suction inlet), and after being pressurized by the ejector → boiler reheater, the next cycle begins, thus forming a hot recirculation. This process realizes the decoupling of the boiler and the steam turbine, and the steam turbine can achieve less steam intake and less power generation, meeting the deep regulation requirements of the power grid, which can be as low as 30% THA power generation (about 90MW), or even less, and at the same time, excess high-quality steam is generated. One is the main steam from the high-pressure steam bypass 19, and the other is the hot resteam from the hot resteam cycle bypass 20. The two steam paths can be used as thermal energy storage (molten salt energy storage) to efficiently heat the steam. For example, in a 300MW system, a certain scale of molten salt-related systems can be configured to generate a storage capacity of 600MWh (100MW*6h) of electricity. In addition, the two steam paths generated by the decoupling of the turbine and boiler can also be used as turbine and boiler decoupling heating steam for heating external users.

[0076] 2) If Figure 3 As shown in the figure, the energy release phase corresponds to the peak period. When the grid dispatch demand is at its peak, the unit is required to generate as much power as possible.

[0077] 2-1) In order to quickly respond to grid demand, the battery is first put into use to release power and the flywheel stores energy for rapid response. The high-speed rotating flywheel uses its inertia to drag the motor to decelerate and generate electricity. At this time, the motor operates as a generator, converting the mechanical energy stored in the flywheel into electrical energy again. After being processed by the power converter, it meets the requirements of frequency modulation and rapid response and outputs electrical energy;

[0078] 2-2) The molten salt energy storage system is put into operation simultaneously. At this time, the molten salt system is in the heat release mode. During the heat release, the heat stored in the molten salt system is released to the feed water system. Part of the feed water flow diverted by the feed water pump is exchanged with the molten salt system at the high pressure heater outlet and then merged into the boiler); the feed water can also be heated to generate saturated steam which enters the main steam system, and the access point is behind the steam drum or behind the steam-water separator; or reheated steam is generated and the cold section steam enters the heat recirculation.

[0079] During the energy release stage, since part of the heat in the thermal power system is provided by molten salt, part of the boiler heat can be replaced by alternative energy storage output, so that the boiler can operate at full output, which is reflected in the maximum power load. Figure 3 As shown, THA330MW is reached. Since the heat stored in molten salt is large (can be set according to demand), it can also be reflected in the abundance of reheated steam. This part of the reheated steam can be used as the steam source of the small steam turbine to drive the small steam turbine to generate electricity. The small steam turbine can be configured according to the output of 90MW, and the small steam turbine is equipped with a corresponding cold end (cooling tower) and online capacity expansion to further achieve the peak. Whether it is the heating season or not, the system can generate peak power through the small steam turbine, thereby meeting the rated peak function throughout the year.

[0080] The application of the above-mentioned embodiment can be replicated to other thermal power plants, and the operation mode is particularly flexible. For example, when performing deep regulation or peak operation, it can meet various dispatching requirements of the power grid.

[0081] The implementation methods of this utility model include system architecture design, boiler decoupling system superimposed energy storage module, electric energy storage module, kinetic energy storage module configuration, control system development, etc. By optimizing the configuration and parameters of each module, efficient operation and flexible scheduling of the thermal power side energy storage system can be achieved.

[0082] This system has the following advantages:

[0083] 1. Fusion batteries and molten salt energy storage complement each other:

[0084] Battery energy storage has the characteristics of fast response, can quickly absorb and release electrical energy, and is suitable for dealing with short-term power fluctuations. Molten salt energy storage has the advantages of long-term, large capacity, and low cost, and is suitable for long-term energy storage and regulation. By combining these two energy storage technologies, the system can take into account the characteristics of frequency regulation, peak regulation, fast response, and long-term low price, thereby improving the stability and economy of the power system.

[0085] 2. Batteries and molten salt work together:

[0086] Batteries are used as an initial means of rapid response in the system, providing a short buffer time to cope with sudden power demand or fluctuations. Molten salt, as a long-term energy storage method, can stably store and release energy to achieve long-term and low-cost energy storage. The two work together to compensate for each other's shortcomings and jointly complete the entire energy storage process.

[0087] 3. Interconnection between the cold end of small machine and the cold end of large machine:

[0088] The small unit cold end not only provides cooling for the small unit, but can also be interconnected with the cold end of the large unit. Through this interconnection method, the small unit cold end can support the large unit to reduce back pressure and improve the operating efficiency of the large unit.

[0089] 4. Use flywheel energy storage module:

[0090] The flywheel energy storage module has an extremely high response speed and can be used as a means of response within seconds to further improve the frequency modulation function of the system. The introduction of the flywheel enables the entire energy storage system to respond more quickly and accurately when facing rapidly changing power demand.

[0091] 4. Economic benefit analysis:

[0092] Battery energy storage system: 45MWh*1500 yuan / kWh=67.5 million yuan (single group); decoupled molten salt system: about 350 million yuan; small steam turbine system and others: about 100 million yuan (including setting up cold end, grid-connected capacity increase, etc.);

[0093] Total cost: 67.5 million yuan + 350 million yuan + 100 million yuan ≈ 520 million yuan

[0094] By integrating the above-mentioned energy storage systems, this solution can effectively replace 600MWh of “new energy storage capacity”.

[0095] Compared with directly building a 600MWh battery energy storage system, based on the latest battery EPC cost of 1,420 yuan / kWh, users need to invest about 850 million yuan (600MWh*1,420 yuan / kWh=852 million yuan). The use of the utility model solution saves 852-520 million yuan in investment.

[0096] In summary, the BDS multi-storage complementary system on the thermal power side based on boiler-turbine decoupling achieves long-term, high-efficiency and fast-response energy storage effect by combining multiple energy storage technologies and optimizing system structure, thereby improving the stability and economy of the power system.

[0097] This technical solution can optimize and upgrade the traditional 300MW subcritical unit (the actual application is not limited to the model) by integrating multiple energy storage technologies (decoupling of turbine and boiler, molten salt energy storage system, battery energy storage, flywheel energy storage) and auxiliary systems (small unit system). This integration not only improves the power generation efficiency and response speed of the unit, but also saves users a lot of investment by replacing the high-cost pure battery energy storage system, making the entire system more competitive in promoting the rapid development of the new energy field.

[0098] Finally, it should be noted that the above description is only an explanation of the utility model and is not intended to limit the utility model. Although the utility model has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A BDS multi-storage complementary system on the thermal power side based on turbine-boiler decoupling, comprising a main steam pipeline, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of a steam turbine, and a boiler reheater; the main steam pipeline is connected to the high-pressure cylinder of the steam turbine, and the hot end outlet of the reheater is connected to the steam inlet pipeline of the intermediate-pressure cylinder; characterized in that: It also has a thermal power boiler decoupling module, a thermal energy storage module and an electrical energy storage module; The thermal power boiler decoupling module is composed of a high-pressure steam bypass, a hot re-steam cycle bypass, and a steam ejector system; the main steam pipeline is connected with a high-pressure steam bypass, and the medium-pressure cylinder steam inlet pipeline is connected with a hot re-steam cycle bypass; the high-pressure steam bypass and the hot re-steam cycle bypass are connected to the steam ejector system to form a hot re-circulation, and the output of the steam ejector system is connected to the cold end inlet of the reheater; A thermal energy storage module is connected to the boiler feed water system, and a high-pressure steam bypass and / or a hot re-steam cycle bypass is connected to the thermal energy storage module; The electric energy storage module is connected to the factory power and / or grid power.

2. According to claim 1, the thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling is characterized in that: It also includes a small steam turbine module, and part of the steam in the unit is connected to the small steam turbine module as a driving steam source.

3. According to claim 1, the thermal power side BDS multi-storage complementary system based on boiler-turbine decoupling is characterized in that: The thermal power boiler decoupling module is connected to the steam ejector system through a high-pressure steam bypass as power steam, and the hot re-steam cycle bypass is connected to the steam ejector system as suction steam. The ejector outlet steam returns to the cold end inlet of the reheater.

4. According to claim 1, the thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling is characterized in that: The thermal energy storage module switches to work. When storing energy, steam is connected through the high-pressure steam bypass and / or the hot re-steam cycle bypass to heat the heat storage medium in the thermal energy storage module. When releasing energy, feed water is connected through the feed water bypass, and the heat storage medium releases heat to heat the boiler feed water to increase the temperature.

5. According to claim 4, the thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling is characterized in that: The thermal energy storage module outputs feed water which is further connected to the steam-water evaporation system, and outputs saturated steam into the main steam system or into the cold end of the reheater.

6. According to claim 1, the thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling is characterized in that: The electric energy storage module uses batteries or capacitors.

7. The thermal power side BDS multi-storage complementary system based on boiler-turbine decoupling according to claim 1 is characterized in that: It also includes a kinetic energy storage module, and the factory power and / or grid power are connected to the kinetic energy storage module to perform mechanical energy storage and mutual conversion with electrical energy.

8. The thermal power side BDS multi-storage complementary system based on boiler-turbine decoupling according to claim 1 is characterized in that: The small steam turbine module is equipped with a small steam turbine cold end, which is also connected to the exhaust pipe of the low-pressure cylinder of the unit's steam turbine to achieve interconnection with the large unit's cold end.

9. The thermal power side BDS multi-storage complementary system based on boiler-turbine decoupling according to claim 2 is characterized in that: The hot resteam cycle bypass is connected to the small steam turbine module as the driving steam source.

10. The thermal power side BDS multi-storage complementary system based on turbine-boiler decoupling according to claim 1 is characterized in that: The high-pressure steam bypass and hot re-steam cycle bypass are connected externally to provide decoupled heating for the turbine and boiler; the medium-pressure cylinder exhaust pipe is connected externally to provide heating for the turbine and boiler sides.

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