Thermal power plant deep peak regulation system and method utilizing high-temperature heat storage energy

Abstract

The invention discloses a thermal power plant deep peak regulation system and method utilizing high-temperature heat storage energy, and belongs to the field of coupling of industrial high-temperature heat storage energy and thermal power plant deep peak regulation. The system comprises a heating unit which is connected with an electric energy conversion and supply unit and / or a heat energy transfer and storage unit so as to convert electric energy or steam heat energy into heat storage energy of heat storage particles; the heat storage unit is used for storing the high-temperature heat storage particles conveyed by the heating unit; the heat release unit is used for receiving the high-temperature heat storage particles conveyed by the heat storage unit; wherein the heat release unit is a fluidized bed boiler in a thermodynamic system of a thermal power plant, so that heat storage energy of the heat storage particles is transmitted to the original thermodynamic system of the thermal power plant, and deep peak regulation of the thermal power plant is realized through overheating thermal power generation with rated parameters generated by the thermodynamic system. By means of the system, the problem that in the deep peak regulation process of an existing thermal power plant, a thermodynamic system of the thermal power plant and an industrial solid-state high-temperature heat energy storage technology are not coupled is solved.

Description

Technical Field

[0001] This application relates to the field of deep peak shaving technology for thermal power plants using industrial high-temperature thermal energy storage coupled with thermal energy storage, and in particular to a deep peak shaving system and method for thermal power plants using high-temperature thermal energy storage. Background Technology

[0002] With the support of national policies, new energy power generation has developed rapidly. Due to the rapid growth in total power generation, the peak-valley load difference of the large power grid has increased to over 30% to 50% and is still rising. In recent years, the newly installed generating units in major power grids have mainly been large-capacity units of 125MW or more. The proportion of large-capacity units in the power grid is increasing, forcing large-capacity units to perform deep peak shaving. As the power system's demand for grid dispatch flexibility and peak shaving capacity continues to increase, the grid peak shaving capacity of thermal power plants, as the main component of power and heat energy supply, has become crucial.

[0003] Traditional thermal power plants primarily rely on the conversion of energy from the combustion of fossil fuels. In the boiler unit, fuel mixes with air and burns, generating a large amount of heat energy to heat water in the boiler unit, turning it into high-temperature, high-pressure steam. This high-temperature, high-pressure steam then enters the turbine, expands, and performs work, driving the generator to produce electricity. Because the boiler unit mainly relies on the boiler burning fossil fuels to generate steam to drive the turbine, its peak-shaving capacity is limited by factors such as the boiler's minimum stable combustion load. Excess heat generated during off-peak hours is difficult to effectively store and utilize, leading to energy waste and insufficient peak-shaving capacity.

[0004] To address the challenges of flexibility and energy efficiency complementarity in deep peak shaving at thermal power plants, it is essential to vigorously develop industrial thermal energy storage technology. As an important new energy storage technology, industrial thermal energy storage possesses inherent advantages in regulating power quality, peak shaving and valley filling, heat transfer, and improving power utilization, playing a crucial role in achieving dual-carbon goals and deep peak shaving of electricity. Thermal energy storage technology holds the promise of storing excess steam heat generated during variable load operation of generating units and releasing this heat as needed to meet variable heating demands, thus expanding the peak-shaving operation range of combined heat and power (CHP) systems.

[0005] However, current technologies for deep peak shaving using industrial energy storage often require the separate installation of heat exchangers. Purchasing a large industrial heat exchanger can cost hundreds of thousands or even millions of yuan. Adding the installation and commissioning costs of supporting equipment, the overall cost is considerable. This is especially true for thermal power plants, where plant space is a limited and precious resource. Installing heat exchangers requires additional space to house the heat exchangers, supporting piping, and maintenance access.

[0006] Therefore, how to integrate industrial thermal energy storage technology with the thermal systems of thermal power plants to achieve the best balance between economy, flexibility, environmental friendliness and deep peak-shaving capability is an important direction for the future development of thermal power plants. Summary of the Invention

[0007] To address the aforementioned problems, one objective of this invention is to provide a deep peak-shaving system for thermal power plants that integrates granular thermal energy storage, thereby solving the problem of the lack of coupling between the thermal power plant's thermal system and industrial thermal energy storage technology in existing deep peak-shaving processes. A second objective of this invention is to provide a deep peak-shaving method for thermal power plants that integrates granular thermal energy storage.

[0008] To achieve one of its objectives, in a first aspect, this invention provides a deep peak-shaving system for thermal power plants that integrates granular thermal energy storage, the technical solution of which is: A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage, the system comprising: A heating unit is used to receive thermal storage particles. The heating unit is connected to an electrical energy conversion and supply unit and / or a thermal energy transfer and storage unit to heat the thermal storage particles so as to convert electrical energy or steam thermal energy into the thermal energy stored in the thermal storage particles. A heat storage unit, connected to the heating unit, is used to store high-temperature heat storage particles delivered by the heating unit; A heat release unit, connected to the heat storage unit, is used to receive the high-temperature heat storage particles transported by the heat storage unit; The heat release unit is a fluidized bed boiler in the thermal system of a thermal power plant, which transfers the thermal energy stored in the heat storage particles to the original thermal system of the thermal power plant. The thermal power generated by the thermal system generates electricity using the rated parameters, thereby realizing the deep peak shaving of the thermal power plant by utilizing the high-temperature thermal energy.

[0009] As one of the preferred embodiments, the power conversion and supply unit includes: an electric heater connected to the heating unit, used to electrically heat the heat storage particles using green electricity; The heat energy transfer and storage unit includes: a main steam bypass system, which is a steam bypass in the thermal system of the thermal power plant, used to circulate excess superheated steam generated by the thermal system; the main steam bypass system is connected to the heating unit and is used to heat the heat storage particles using the excess superheated steam.

[0010] As one preferred embodiment, the heating unit includes a heated fluidized bed furnace, which is used to fluidize and heat the heat storage particles located therein.

[0011] As one preferred embodiment, the thermal storage unit includes a fluidized bed high-temperature storage tank, which is used to distribute the high-temperature thermal storage particles located therein in a fluidized state; and... The fluidized bed high-temperature storage tank is connected to the outlet of the heated fluidized bed furnace and the inlet of the fluidized bed boiler, respectively, and is used to store and transport the high-temperature heat storage particles.

[0012] As one of the preferred embodiments, the thermal storage unit further includes a cryogenic storage tank, which is connected to the inlet of the heated fluidized bed furnace and the outlet of the fluidized bed boiler, respectively, for storing the cryogenic thermal storage particles after heat transfer from the fluidized bed boiler, and for returning the cryogenic thermal storage particles to the heated fluidized bed furnace.

[0013] As one preferred embodiment, the system further includes a fan system, the fan system comprising: A fluidizing blower is connected to the fluidized bed high-temperature storage tank and is used to fluidize the high-temperature heat storage particles in the fluidized bed high-temperature storage tank; A conveying fan, connected to the fluidized bed boiler, is used to convey low-temperature heat storage particles that have released their high-temperature heat source within the fluidized bed boiler.

[0014] As one of the preferred options, the heat storage particles include at least one of fine ash mineral sand, coal gangue grinding particles, sand and gravel fine particles, zirconium oxide fine ash particles, and alumina fine particles.

[0015] As one preferred embodiment, the thermal system includes: The fluidized bed boiler; The water supply system is connected to the fluidized bed boiler; The steam drum system is connected to the fluidized bed boiler; The superheater is connected to the steam drum system via the first steam drum steam pipeline, and the superheater is connected to the steam turbine of the thermal power plant via the main steam header; The high-pressure heater is connected to the steam drum system via the second steam drum steam pipeline, and the high-pressure heater is connected to both the feedwater system and the boiler steam drum system. The fluidized bed boiler is used to receive the high-temperature thermal storage particles and the feedwater provided by the feedwater system, so that the thermal energy stored in the high-temperature thermal storage particles is transferred to the feedwater, and the feedwater is converted into saturated steam and flows into the steam drum system for steam-water separation. The separated saturated steam flows into the superheater through the first steam drum steam pipeline and is heated to superheated steam with rated parameters. The superheated steam then enters the steam turbine through the main steam header, directly achieving deep peak shaving for the thermal power plant; and / or, The separated saturated steam flows into the high-pressure heater through the second steam drum steam pipeline, mixes with the feedwater, and then enters the boiler drum system, indirectly realizing deep peak shaving in the thermal power plant.

[0016] As one preferred embodiment, the heat release unit further includes: An air preheater is connected to both the fluidized bed boiler and the water supply system. The water supply system is also connected to the fluidized bed boiler via an air duct to recover the heat energy of the fluidizing air in the fluidized bed boiler.

[0017] To achieve the second objective, the present invention provides a deep peak-shaving method for integrating granular thermal energy storage in thermal power plants, the technical solution of which is: A deep peak-shaving method for thermal power plants integrating pellet thermal energy storage, the method comprising the following steps: The energy storage particles are filled into the heating unit, and the energy storage particles are heated by the power conversion supply unit and / or the heat transfer energy storage unit to convert electrical energy or steam heat energy into the heat storage energy of the heat storage particles. Utilize thermal storage units to store heated high-temperature energy storage particles; Stop fuel combustion in the fluidized bed boiler in the thermal system of the thermal power plant, and introduce the high-temperature energy storage particles from the thermal storage unit into the fluidized bed boiler to transfer the thermal energy stored in the thermal storage particles to the original thermal system of the thermal power plant. The thermal system is used to convert the thermal energy stored in the thermal storage particles into steam with rated parameters for thermal power generation, thereby achieving deep peak shaving of the thermal power plant by utilizing high-temperature thermal energy.

[0018] Compared with the prior art, this application has the following advantages: This application provides a deep peak-shaving system for thermal power plants integrating granular thermal energy storage. The system includes: a heating unit for receiving thermal energy storage granules, the heating unit being connected to an electrical energy conversion and supply unit and / or a thermal energy transfer and storage unit, for heating the thermal energy storage granules to convert electrical energy or steam thermal energy into the thermal energy storage energy of the thermal energy storage granules; a thermal energy storage unit connected to the heating unit for storing the high-temperature thermal energy storage granules transported by the heating unit; and a heat release unit connected to the thermal energy storage unit for receiving the high-temperature thermal energy storage granules transported by the thermal energy storage unit. The heat release unit is a fluidized bed boiler in the thermal system of the thermal power plant, for transferring the thermal energy storage of the thermal energy storage granules to the existing thermal system of the thermal power plant, and generating electricity through the rated parameters of the thermal system, thereby achieving deep peak-shaving of the thermal power plant using the high-temperature thermal energy storage.

[0019] The system provided in this application, based on the traditional thermal power plant thermal system, utilizes a grid thermal unit, adding a thermal storage unit and a heat release unit as energy storage conversion units. During periods of low electricity load, the grid thermal unit heats the thermal storage particles to generate heat energy, the thermal storage unit stores the heat energy from the particles, and the heat release unit releases the heat energy, constructing a closed loop of "heat generation-storage-release," and utilizing grid off-peak periods to achieve peak shifting and valley filling. During peak load periods, the high-temperature thermal storage particles, storing a large amount of heat energy, transfer this heat energy to the thermal power plant's thermal system in the heat release unit, heating boiler feedwater to produce steam for power generation, thus releasing the heat energy. With the help of high-temperature thermal storage particles, heat is stored during off-peak hours at night and released during peak hours during the day, eliminating the need to burn fossil fuels. This allows the thermal power plant to respond quickly to grid load changes, enhancing the flexibility and scope of grid peak shaving for the plant, while simultaneously achieving low-carbon operation.

[0020] The system provided in this application embodiment replaces some circulating fluidized bed coal-fired boilers or uses fluidized bed boilers in thermal power plant units as heat release units during deep peak shaving. It makes full use of existing coal-fired boilers, does not rely on the combustion of fossil fuels, and the boiler itself no longer serves as a conversion device but as an energy transfer intermediate. It directly reuses the heat exchange function of existing boilers, retains the original thermal processes such as evaporation and superheating systems of the boiler unit, the supporting heat exchange channels, and valves on the pipelines. There is no need to build new large-scale heat exchange equipment such as dedicated gas-solid / gas-liquid heat exchangers, avoiding the investment of additional equipment and significantly reducing equipment investment, pipeline layout complexity, installation workload, and space occupation.

[0021] In this way, the thermal energy transmission process is completed by the fluidized bed boiler in the thermal system of the thermal power plant. Coupled with industrial thermal energy storage technology, it realizes the storage and release of thermal energy. It can become the most economical, environmentally friendly and operationally responsive multi-energy complementary system in thermal power plants, and has the triple value of deep peak shaving, carbon emission reduction and asset reuse.

[0022] The method described above has the same advantages over existing technologies as the system described above, and will not be repeated here. Attached Figure Description

[0023] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a process flow diagram of a deep peak-shaving system for thermal power plants that integrates granular thermal energy storage, as described in an embodiment of this application. Figure 2This is a schematic diagram illustrating the working principle of a heated fluidized bed furnace according to an embodiment of this application; Figure 3 This is a system architecture diagram of a deep peak-shaving system for thermal power plants integrating granular thermal energy storage, as described in an embodiment of this application. Figure 4 This is a flowchart of the steps of a deep peak-shaving method for integrating granular thermal energy storage in a thermal power plant, as described in an embodiment of this application.

[0025] Explanation of reference numerals in the attached figures: 1. Heated fluidized bed furnace; 2. High-temperature fluidized bed storage tank; 3. Low-temperature storage tank; 4. Fluidized bed boiler; 5. Feedwater preheater; 6. Feedwater pump; 7. Steam drum system; 8. Superheater; 9. High-pressure heater; 10. Boiler steam drum system; 11. Air preheater. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] It is understood that a thermal power plant is a complex composed of multiple systems and equipment, including boiler units and turbine generator units, which together form a complete thermal system. The boiler units are responsible for generating steam, while the turbine generator units convert the steam's thermal energy into mechanical energy and then into electrical energy. Specifically, a boiler unit typically includes a boiler, feedwater system, evaporator, superheater 8, reheater, and heat exchange pipes. These various devices work together to heat the feedwater supplied by the feedwater system and convert it into high-temperature, high-pressure steam, which is then used by the turbine of the turbine generator unit. The turbine generator unit includes a turbine and a generator, with the turbine connected to both the superheater 8 and the generator. The turbine in the turbine generator unit receives superheated steam from the superheater 8 and converts the superheated steam's thermal energy into mechanical energy.

[0028] For ease of understanding later, this invention is based on the technical modification of the thermal power system of a traditional thermal power plant. Therefore, the operating principle and structural composition of the thermal power system can be referenced from existing thermal power plants. In the thermal power system of a traditional thermal power plant, the boiler in the boiler unit is an energy conversion device, which is a mechanical device that converts the combustion energy of fossil fuels into steam heat energy.

[0029] The working principle of the boiler unit is as follows: Based on the existing industrial thermal energy storage technologies mentioned in the background section, where heat exchangers are added, the primary function of traditional heat exchangers is to transfer heat energy through convection, conduction, or radiation. Through years of practical experience and professional knowledge in thermal power plants, the inventors discovered that the thermal systems of power plants inherently possess a complete multi-stage heat exchange process and supporting heat exchange channels, and that the boilers in the boiler units have large heat exchange areas and the capacity to achieve heat exchange. Therefore, flexible retrofitting of thermal power plants, replacing some circulating fluidized bed coal-fired boilers or utilizing the fluidized bed boilers in the power plant's thermal units, can fully reuse the boilers' heat exchange potential and potentially expand the functionality of the boiler units without altering the original plant structure and layout.

[0030] In view of this, the present invention aims to utilize the grid thermal unit, coupled with two energy storage and conversion units, on the basis of the traditional thermal power plant thermal system. Through fuel replacement, the combustion heat energy of fossil fuels is directly replaced with green and economical thermal energy storage. The thermal energy storage is then directly converted into steam heat energy and finally into electricity through the operation of the thermal power plant's thermal system, utilizing peak-shifting periods of the grid to achieve peak shaving and valley filling. To achieve efficient thermal coupling between industrial thermal energy storage technology and the thermal power plant's thermal system, realizing peak-shifting conversion, energy storage, and energy release, refer to... Figure 1 and Figure 3 , Figure 1 This is a process flow diagram of the deep peak-shaving system for thermal power plants integrating granular thermal energy storage, as shown in this invention. Figure 3 This is a system architecture diagram of a deep peak-shaving system for thermal power plants integrating particle thermal energy storage, as shown in this invention. Figure 1 and Figure 3 As shown, this invention provides a deep peak-shaving system for thermal power plants integrating granular thermal energy storage. The system includes: a heating unit for receiving thermal energy storage granules, connected to an electrical energy conversion and supply unit and / or a thermal energy transfer and storage unit, for heating the thermal energy storage granules to convert electrical energy or steam thermal energy into the thermal energy storage energy of the granules; a thermal energy storage unit connected to the heating unit for storing the high-temperature thermal energy storage granules transported by the heating unit; and a heat release unit connected to the thermal energy storage unit for receiving the high-temperature thermal energy storage granules transported by the thermal energy storage unit. The heat release unit is a fluidized bed boiler 4 in the thermal system of the thermal power plant, which transfers the thermal energy storage of the granules to the existing thermal system of the thermal power plant, generating electricity through the rated parameters of the thermal system, thereby achieving deep peak-shaving of the thermal power plant using the high-temperature thermal energy storage.

[0031] In this embodiment, relying on the thermal system of a thermal power plant, three energy storage conversion process units—a heating unit, a thermal storage unit, and a heat release unit—are added to the existing process. In the heating unit, the interior is filled with thermal storage particles. This heating unit can be connected to the grid's thermal system, which heats the thermal storage particles, raising their temperature and transforming them into high-temperature thermal storage particles, thus storing thermal energy. The thermal storage unit receives the high-temperature thermal storage particles from the heating unit, serving as the core thermal storage device for high-temperature thermal energy storage. The heat release unit is a crucial component for carrying, transferring, and converting thermal energy. It receives the high-temperature thermal storage particles from the thermal storage unit and uses the stored thermal energy to produce steam with rated parameters through the thermal system of the thermal power plant, ensuring a timely and high-quality supply of steam for power generation or heating.

[0032] In this embodiment, the power conversion and supply unit and the heat transfer and storage unit can achieve automatic control and DCS system linkage control through autonomous calculation and automatic control switching system.

[0033] In the thermal power plant's thermal system, some circulating fluidized bed coal-fired boilers and fluidized bed boilers 4 in the power plant's thermal unit can both be used as fluidized bed boilers 4. The combustion methods of boilers in the thermal power plant's thermal system can be divided into suspension combustion, boiling combustion, diffusion combustion, etc., therefore boilers can be divided into pulverized coal boilers, fluidized bed boilers 4, chain grate boilers, fixed bed boilers, etc. The most technologically mature and widely used industrial boilers are mainly pulverized coal boilers and circulating fluidized bed boilers 4. Among them, pulverized coal boilers are the most technologically mature and widely used boiler type. Fluidized bed boilers 4, with their low energy consumption, high combustion efficiency, strong adaptability to various coal types, and wide applicability, are the mainstream new type of boiler used today. Therefore, in this embodiment, some circulating fluidized bed coal-fired boilers and fluidized bed boilers 4 in the power plant's thermal unit can both be used as fluidized bed boilers 4 as heat release units. For example... Figure 3 As shown, a fluidized bed boiler 4 typically includes a furnace, a cyclone separator, and a vertical flue. The fluidized bed boiler 4 also features its own fluidizing air system. Based on fluidized bed technology, it uses an inert, highly heat-transferring fluidizing gas (such as nitrogen or argon) to carry the high-temperature heat storage particles into a fluidized state, achieving efficient gas-solid two-phase heat transfer. This prevents the high-temperature heat storage particles from densely accumulating at the bottom of the boiler furnace. Sufficient fluidized heat transfer prevents high-temperature agglomeration and reduces the risk of thermal stress accumulation.

[0034] Therefore, this embodiment of the invention can utilize a grid thermal unit coupled with industrial energy storage technology on the basis of a traditional thermal power plant's thermal system. During periods of low electricity load, the grid thermal unit heats the thermal storage particles to achieve thermal energy storage. During peak load periods, the high-temperature thermal storage particles, storing a large amount of thermal energy, exchange heat with the feedwater provided by the thermal power plant's feedwater system in a fluidized bed boiler 4. This heats the feedwater to produce steam for power generation, releasing the thermal energy and constructing a closed loop of heat generation-storage-release. By using high-temperature thermal storage particles, excess heat during off-peak hours is stored and released during peak hours, utilizing grid off-peak periods to achieve peak shifting and valley filling.

[0035] During deep peak shaving, the fluidized bed boiler 4 does not rely on the combustion of fossil fuels. The boiler itself no longer serves as a conversion device but as an energy transfer intermediate, directly reusing the heat exchange function of the existing boiler. It retains the original evaporation and superheating systems, thermal processes, supporting heat exchange channels, and valves on the pipelines of the boiler unit. There is no need to build new large-scale heat exchange equipment such as dedicated gas-solid / gas-liquid heat exchangers, avoiding additional equipment investment and significantly reducing equipment investment, pipeline layout complexity, installation workload, and space occupation. In this way, it can replace part of the circulating fluidized bed coal-fired boilers or use the fluidized bed boiler 4 in the power plant's thermal system as a high-temperature heat-releasing fluidized bed furnace. Combined with industrial thermal energy storage technology, it can realize the generation, storage, and release of thermal energy. It can become the most economical, environmentally friendly, and operationally responsive multi-energy complementary system in thermal power plants, possessing the triple value of deep peak shaving, carbon emission reduction, and asset reuse.

[0036] Using the fluidized bed boiler 4 in the thermal power plant's thermal system as a thermal energy transmission unit can reduce the overall equipment investment, make full use of existing coal-fired boilers, increase equipment utilization and commissioning time by 2000 hours, and at the same time reduce carbon emissions by 20%-30%.

[0037] Fluidized bed boiler 4 is used for the transfer of thermal energy storage, with a heat exchange efficiency of ≥85% and a temperature fluctuation of ≤±3.2℃ during the heat release process. It supports 23%-100% load regulation of the thermal system and unit, without the need to burn fossil fuels. The thermal power plant can quickly respond to changes in grid load, enhance the flexibility of grid peak shaving of the thermal power plant and expand the peak shaving range, and at the same time realize the low-carbon operation of the thermal power plant.

[0038] It should be explained that in the flexible retrofitting of thermal power plants, the existing boiler's furnace and the high-temperature flue gas duct that shares the same flow path with the flue gas generated from fuel combustion can be used as a particle flow duct for high-temperature particles. The high-temperature heat storage particles are equivalent to the high-temperature flue gas exchanging heat with the boiler's feedwater within the furnace and duct, achieving efficient thermal coupling with the feedwater system. Alternatively, it is sufficient to simply add inlet and outlet ports to the existing boiler, connecting them to the heat storage unit via corresponding inlet and outlet pipes, allowing the high-temperature heat storage particles to smoothly enter and exit the boiler's furnace.

[0039] In some embodiments, the feed pipe of the fluidized bed boiler 4 is connected to the fluidized bed high-temperature storage tank 2, and the discharge pipe is connected to the low-temperature storage tank 3. The fluidized bed high-temperature storage tank 2 and the low-temperature storage tank 3 are respectively connected to the inlet and outlet of the heating fluidized bed furnace 1.

[0040] As a further explanation of this embodiment, the boiler unit of this embodiment of the invention operates in conjunction with thermal storage particles, which can reasonably switch the boiler's operating mode, further adjust the power generation and heating method, expand the adaptability to changes in grid load, and improve operational flexibility. Compared with the operating mode of relying solely on fossil fuel combustion power generation and industrial energy storage peak shaving power generation, the fluidized bed boiler 4 in this invention can select from multiple power generation modes by switching the valves on the corresponding pipelines, thereby improving the selectivity of energy utilization.

[0041] In normal operation, boiler units can flexibly switch between combustion and heat exchange modes. In combustion mode, the boiler burns pulverized coal to generate electricity; in heat exchange mode, it utilizes the heat from thermal storage pellets to generate electricity. Existing boilers in thermal power plants switch energy supplies under different operating conditions, achieving efficient switching and utilization of different energy forms (chemical energy from fossil fuels and thermal energy stored in thermal storage pellets) within the same equipment, thus improving system coupling.

[0042] For example, in heat exchange mode, during off-peak hours, excess electricity is used to heat the energy storage particles, while the particles release heat to generate electricity; during peak hours, the high-temperature heat storage particles containing a large amount of heat energy continue to generate electricity.

[0043] For example, in combustion mode, during off-peak or peak electricity demand, only fluidized bed boiler 4 is used to burn fossil fuels for power generation.

[0044] For example, in a dual-mode system of heat exchange and combustion, thermal storage pellets can be used to generate electricity alongside fossil fuel combustion, adapting to different operating conditions. In this mode, a cyclone separator can be installed on the fluidized bed boiler 4 to separate pulverized coal and thermal storage pellets for the recovery of the thermal storage pellets.

[0045] It is worth mentioning that this invention is also applicable to boilers that are out of service or abandoned. By utilizing the existing infrastructure and supporting thermal system of the boiler itself, it can be used only in heat exchange mode, thereby realizing the high-value utilization of the asset.

[0046] In some embodiments, when the high-temperature particle energy storage is insufficient, the system can switch to the boiler combustion mode to ensure the continuity of power supply.

[0047] Preferably, the present invention is used only in heat exchange mode, completely stopping the combustion of fossil fuels and reducing carbon emissions.

[0048] Preferably, the power conversion and supply unit includes: an electric heater connected to the heating unit for using green electricity to electrically heat the thermal storage particles; the heat transfer and storage unit includes a main steam bypass system, which is a steam bypass in the thermal power plant's thermal system for circulating excess superheated steam generated by the thermal system; the main steam bypass is connected to the heating unit for using excess superheated steam to heat the thermal storage particles.

[0049] In this embodiment, as Figure 2 As shown, Figure 2 This is a schematic diagram illustrating the working principle of the heated fluidized bed furnace 1. The heating source for the heated fluidized bed furnace 1 can be either a heat transfer energy storage unit or an electrical energy conversion supply unit. Heat transfer energy storage unit heating refers to storing excess superheated steam in the form of granular thermal energy within the heating unit during periods when the power plant indirectly supplies heat to users or during off-peak electricity demand. Electrical energy conversion supply unit heating refers to using electricity generated from wind or solar energy to heat the thermal energy storage granules, which are then stored in the heating unit as granular thermal energy. During the electric heating process, the heated fluidized bed furnace 1 is connected to green energy substations such as those powered by wind, hydro, or solar power. Using electric or steam heating can provide a stable high-temperature heat source for energy-intensive industries such as chemical and metallurgical industries.

[0050] In the steam heating mode, the heating unit is connected to the main steam bypass system of the thermal power plant, introducing the surplus superheated steam from the main steam bypass system into the heating unit. Therefore, during periods of low electricity demand, based on the thermal system of the thermal power plant, the surplus superheated steam provided by the main steam bypass system enters the heating unit and exchanges heat with the heat storage particles within the heating unit, causing the temperature of the heat storage particles to rise and transform them into high-temperature heat storage particles.

[0051] In this system, the main steam bypass system of a thermal power plant can be a bypass connecting the superheater, reheater, or turbine outlet. Excess superheated steam generated during periods of low electricity demand is introduced into the heating units through this bypass. Therefore, coal-fired power, as a crucial energy source, combined with thermal energy storage pellets, can effectively store and utilize excess heat during low-load operation of thermal power plants outside of peak heating periods, thus expanding the peak-shaving operation range of thermal power plants.

[0052] In the electric heating mode, green energy (such as solar thermal and wind power) from the grid's thermal unit is used to heat the thermal storage particles. The heat is stored electrically during off-peak hours at night and released during peak hours in the daytime, reducing wind and solar power curtailment and achieving renewable energy integration. This embodiment uses an electric heater with a thermal efficiency of ≥95%.

[0053] Preferably, the heating unit includes a heated fluidized bed furnace 1, which is used to fluidize and heat the heat storage particles located therein. In this embodiment, fluidized heating is used during the high-temperature heating process of the heat storage particles, and the gas and solid phases are in full contact within the heated fluidized bed furnace 1, ensuring the uniformity of the flow rate and temperature field for carrying and transporting the heat storage energy.

[0054] Preferably, the thermal storage unit includes a fluidized bed high-temperature storage tank 2, which is used to distribute the high-temperature thermal storage particles located therein in a fluidized state; and the fluidized bed high-temperature storage tank 2 is connected to the outlet of the heating fluidized bed furnace 1 and the inlet of the fluidized bed boiler 4, respectively, for storing and transporting the high-temperature thermal storage particles.

[0055] In this embodiment, the thermal storage unit employs a high-temperature fluidized bed thermal energy storage system. Therefore, both the thermal storage and heat release units are based on fluidized bed technology. An inert, highly heat-transferring fluidizing gas (such as nitrogen or argon) carries the thermal storage particles in a fluidized state within both units. This ensures sufficient contact between the gas and solid phases within the fluidized bed, guaranteeing the uniformity of the flow rate and temperature field for carrying and transporting the stored energy, as well as controllable heat transfer. This enables continuous production, resulting in a simple process, strong operability, and significant economic benefits. A thermal storage density of 300 MJ / m³ is employed. 3 -500 MJ / m 3 (Ultra-high temperature sensible heat storage) Temperature field uniformity deviation ≤ ±5℃. In the two energy storage conversion units, the heat storage / release rate has a wide adjustable range (23%-100% load), adapting to the grid's rapid peak-shaving needs. Simultaneously, fluidized bed design avoids particle agglomeration, ensuring full fluidized heat transfer, preventing high-temperature agglomeration, and reducing the risk of thermal stress accumulation.

[0056] As a specific explanation of this embodiment, the system also includes a fan system, which includes: A fluidizing blower, connected to the fluidized bed high-temperature storage tank 2, is used to fluidize the high-temperature heat storage particles within the fluidized bed high-temperature storage tank 2. A conveying blower, connected to the fluidized bed boiler 4, is used to convey the low-temperature heat storage particles within the fluidized bed boiler 4 after the high-temperature heat source has been released. In this embodiment, fluidizing air is provided by the fluidizing blower and the conveying blower, ensuring sufficient contact between the gas and solid phases during the flow process in the high-temperature heat storage system, guaranteeing the uniformity of the flow rate and temperature field of the heat storage particles, as well as the controllability of heat transfer.

[0057] Both the fluidizing blower and the conveying blower are Roots blowers.

[0058] As a further explanation of this embodiment, the heated fluidized bed furnace 1 is positioned above the fluidized bed high-temperature storage tank 2. The heat storage particles are conveyed from the heated fluidized bed furnace 1 to the fluidized bed high-temperature storage tank 2 by gravity. The fluidized bed boiler 4 is directly connected to the heated fluidized bed furnace 1 via a conveying fan to pneumatically return the low-temperature heat storage particles to the heated fluidized bed furnace 1. The fluidized bed high-temperature storage tank 2 is connected to both the heated fluidized bed furnace 1 and the fluidized bed boiler 4, and through a combination of gravity and pneumatic conveying, the flow path of the heat storage particles can be optimized, achieving efficient recycling of the heat storage particles, reducing energy loss, and improving the overall system efficiency.

[0059] In a further technical solution, the thermal storage unit also includes a low-temperature storage tank 3, which is connected to the inlet of the heated fluidized bed furnace 1 and the outlet of the fluidized bed boiler 4, respectively, for storing the low-temperature thermal storage particles after heat transfer from the fluidized bed boiler 4, and for returning the low-temperature thermal storage particles to the heated fluidized bed furnace 1.

[0060] In this embodiment, the inlet of the fluidized bed high-temperature storage tank 2 is connected to the outlet of the heating fluidized bed furnace 1, and the outlet is connected to the inlet of the fluidized bed boiler 4. During periods of low electricity load, surplus superheated steam from the power plant is introduced into the heating fluidized bed furnace 1 through the main steam bypass system, or the thermal storage particles are heated using an electric heater. The high-temperature thermal storage particles flow from the heating fluidized bed furnace 1 into the fluidized bed high-temperature storage tank 2 via gravity conveying and are stored in the fluidized bed high-temperature storage tank 2. During periods of standby electricity demand, the high-temperature thermal storage particles are transported from the fluidized bed high-temperature storage tank 2 to the fluidized bed boiler 4 to heat the boiler feedwater and generate steam to supply the turbine generator set, achieving deep peak shaving of electricity.

[0061] The inlet of the cryogenic storage tank 3 is connected to the outlet of the fluidized bed boiler 4, and the outlet is connected to the inlet of the heating fluidized bed furnace 1. After the high-temperature heat storage particles exchange heat with the boiler feedwater in the fluidized bed boiler 4, the temperature of the heat storage particles decreases, becoming cryogenic heat storage particles. These cryogenic particles are transported from the fluidized bed boiler 4 to the cryogenic storage tank 3 for storage, and then transported to the heating fluidized bed furnace 1 for heating during the next low-load period, forming a heat storage and release cycle on the particle side.

[0062] The storage time of the heat storage particles in the fluidized bed high-temperature storage tank 2 varies depending on summer and winter. The minimum heat storage time can be designed to be 2h-24h, and the heat storage temperature is 400℃-2000℃.

[0063] In conjunction with the above embodiments, the thermal system includes: a fluidized bed boiler 4; a feedwater system connected to the fluidized bed boiler 4; a steam drum system 7 connected to the fluidized bed boiler 4; a superheater 8 connected to the steam drum system 7 via a first steam drum pipeline, and the superheater 8 is connected to the steam turbine of the thermal power plant via a main steam header; and a high-pressure heater 9 connected to the steam drum system 7 via a second steam drum pipeline, and the high-pressure heater 9 is connected to both the feedwater system and the boiler steam drum system 10. Among them, the fluidized bed boiler 4 is used to receive high-temperature thermal storage particles and feedwater provided by the feedwater system, so that the thermal energy stored in the high-temperature thermal storage particles is transferred to the feedwater, and the feedwater is converted into saturated steam and flows into the steam drum system 7 for steam-water separation. The separated saturated steam flows into the superheater 8 through the first steam drum steam pipeline and is heated to superheated steam with rated parameters. The superheated steam enters the steam turbine through the main steam header, directly realizing deep peak shaving in the thermal power plant; and / or, the separated saturated steam flows into the high-pressure heater 9 through the second steam drum steam pipeline, mixes with feedwater and enters the boiler drum system 10, indirectly realizing deep peak shaving in the thermal power plant.

[0064] In this embodiment, the thermal energy stored in the high-temperature thermal storage particles releases heat in the fluidized bed boiler 4 to heat the feedwater pumped by the feedwater system. The feedwater pump 6 is connected to a third control valve (e.g., Figure 1 The FV03 control valve (in the boiler) controls the flow of boiler feedwater into the feedwater preheater 5. The feedwater preheater 5 is connected to the fluidized bed boiler 4 via a water channel. The boiler feedwater is converted into saturated steam in the fluidized bed boiler 4 and flows into the steam drum system 7. After a steam-water separation process in the steam drum, the saturated steam and boiler feedwater are separated. The superheater 8 is connected to the steam drum system 7 through the first steam drum pipeline. The superheater 8 heats the separated saturated steam to superheated steam with rated parameters. The superheated steam passes through the first control valve (e.g., FV03). Figure 1 The FV01 in the middle is connected to the main steam header of the thermal power plant. The main steam header delivers superheated steam to the steam turbine, which drives the steam turbine to generate electricity, directly realizing deep peak shaving of the thermal power plant.

[0065] In this embodiment, during periods of low grid load, the heat release rate and superheated steam flow of the fluidized bed boiler 4 can be controlled by adjusting the opening of the first and third control valves, thereby directly adjusting the power generation capacity. This reduces the power consumption during periods of low grid load and increases the power consumption during periods of high load, adapting to changes in grid load while maintaining stable unit operation.

[0066] More specifically, the steam drum system 7 is connected to the high-pressure heater 9 via a second steam drum pipeline. The high-pressure heater 9 is connected to both the feedwater system and the boiler steam drum system 10. In addition to being connected to the superheater 8 for direct deep peak shaving in the power plant, the steam drum system 7 is also connected to the high-pressure heater 9 via the second steam drum pipeline. A second control valve (such as...) is installed on the second steam drum pipeline. Figure 1The saturated steam separated from the steam drum system 7 (FV02) can flow into the high-pressure heater 9 to mix with the boiler feedwater before entering the boiler drum system 10, indirectly achieving deep peak shaving in the thermal power plant. Specifically, the boiler feedwater absorbs some heat from the saturated steam in the high-pressure heater 9, raising its temperature. The preheated boiler feedwater then enters the boiler drum for steam-water separation, and the separated boiler feedwater is sent to the feedwater preheater 5 or the fluidized bed boiler 4, thereby reducing the heat required for the feedwater preheater 5 to heat cold water or for the fluidized bed boiler 4 to heat the feedwater.

[0067] In another embodiment, the boiler unit further includes an air preheater 11, which is connected to both the fluidized bed boiler 4 and the feedwater system. The feedwater system is also connected to the fluidized bed boiler 4 via a duct. In this embodiment, the air preheater 11 preheats the fluidizing air, which is then introduced into the fluidized bed boiler 4 to fluidize the high-temperature heat storage particles and enhance heat exchange efficiency. The fluidizing air absorbs heat energy after performing work and can be recovered. The fluidizing air is connected to the feedwater preheater 5 via a duct, allowing the boiler feedwater to absorb the heat energy from the fluidizing air in contact with the high-temperature heat storage particles. The fluidizing air, having undergone initial heat recovery, continues to be connected to the air preheater 11 via a duct, further absorbing heat energy before being discharged into the air.

[0068] Preferably, the thermal storage particles include at least one of the following high-temperature resistant solid thermal storage fine ash particles: fine ash mineral sand, ground coal gangue particles, fine sand and gravel particles, fine zirconia ash particles, and fine alumina particles. The solid thermal storage particles, such as coal gangue, sand and gravel particles, zirconia ceramics, and alumina ceramics, are heated to 800℃-2500℃ (depending on the material properties) to achieve high-density thermal energy storage.

[0069] In summary, this invention focuses on the integration of renewable energy and the enhancement of thermal power peak-shaving capacity. It flexibly transforms the thermal systems of thermal power plants, utilizing grid thermal units and achieving industrial high-temperature thermal energy storage and deep peak-shaving in thermal power plants through three energy storage conversion process units: heating unit, thermal storage unit, and thermal release unit. By directly replacing the combustion heat energy of fossil fuels with green and economical thermal energy storage in the existing thermal systems of thermal power plants, and directly converting the stored thermal energy into steam heat energy, and finally into electricity, this invention establishes a highly efficient thermal coupling between industrial thermal energy storage with peak-shaving capabilities and thermal power plants as the main power generation source. This achieves peak-shifting conversion, energy storage, and energy release, and promotes the upgrading and iteration of domestic technologies such as high-temperature thermal storage materials (e.g., magnesium-based thermal storage alloys), fluidized bed equipment, and intelligent control systems.

[0070] In deep peak-shaving technology, the minimum load rate of the unit can be reduced to 23% (compared to about 40% for traditional units), with a significant reduction in response time. The total life-cycle cost of the thermal energy storage system is 20% lower than that of phase change energy storage and gas phase energy storage. This technology provides a feasible path for the low-carbon transformation of the thermal power industry and can be coupled with technologies such as molten salt thermal energy storage and hydrogen energy storage in the future to build a multi-energy complementary energy system, contributing to the achievement of "dual carbon" goals. The entire system can achieve continuous production, with simple processes, strong operability, and significant economic benefits.

[0071] Correspondingly, regarding the second aspect, please refer to Figure 4 , Figure 4 A flowchart illustrating the steps of a deep peak-shaving method for integrating pelletized thermal energy storage in a thermal power plant. This invention also provides a deep peak-shaving method for integrating pelletized thermal energy storage in a thermal power plant, utilizing the deep peak-shaving system for integrating pelletized thermal energy storage in a thermal power plant provided in the first aspect of this invention. The method includes the following steps: S1. Fill the energy storage particles into the heating unit, and at the same time use the power conversion supply unit and / or the heat transfer energy storage unit to heat the energy storage particles, so as to convert the electrical energy or steam heat energy into the heat storage energy of the heat storage particles. S2. Utilize thermal storage units to store heated high-temperature energy storage particles; S3. Stop the fuel combustion of the fluidized bed boiler 4 in the thermal system of the thermal power plant, and introduce high-temperature energy storage particles from the heat storage unit into the fluidized bed boiler 4 to transfer the heat storage energy of the heat storage particles to the original thermal system of the thermal power plant. S4. The thermal energy stored in the thermal storage particles is converted into steam with rated parameters using a thermal power system for thermal power generation, thereby achieving deep peak shaving of thermal power plants by utilizing high-temperature thermal energy.

[0072] It should be noted that, for the method embodiments, the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps may be performed in other orders or simultaneously.

[0073] The above method embodiments are basically similar to the system embodiments, so the description is relatively simple. For relevant details, please refer to the description of the system embodiments.

[0074] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0075] It should also be noted that, in this document, the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device.

[0076] The above provides a detailed description of a deep peak-shaving system and method for thermal power plants utilizing high-temperature thermal energy storage, as provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of aiding understanding this application, and the content of this specification should not be construed as limiting this application. Furthermore, those skilled in the art will recognize that various modifications and variations in the specific implementation methods and application scope may occur based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and any obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage, characterized in that, The system includes: A heating unit is used to receive thermal storage particles. The heating unit is connected to an electrical energy conversion and supply unit and / or a thermal energy transfer and storage unit to convert electrical energy into thermal energy to heat the thermal storage particles, so as to convert electrical energy or steam thermal energy into the thermal storage energy of the thermal storage particles. A heat storage unit, connected to the heating unit, is used to store high-temperature heat storage particles delivered by the heating unit; A heat release unit, connected to the heat storage unit, is used to receive the high-temperature heat storage particles transported by the heat storage unit; The heat release unit is a fluidized bed boiler in the thermal system of a thermal power plant, which transfers the thermal energy stored in the heat storage particles to the original thermal system of the thermal power plant. The thermal system generates superheated thermal power through rated parameters, thereby realizing deep peak shaving of the thermal power plant by utilizing high-temperature thermal energy.

2. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage as described in claim 1, characterized in that, The power conversion and supply unit includes an electric heater connected to the heating unit, used to electrically heat the heat storage particles using green electricity; The thermal energy transfer and storage unit includes a main steam bypass system connected to the heating unit for circulating the surplus superheated steam to heat the thermal storage particles.

3. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage as described in claim 1, characterized in that, The heating unit includes a heated fluidized bed furnace, which is used to fluidize and heat the heat storage particles located therein.

4. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage as described in claim 3, characterized in that, The thermal storage unit includes a fluidized bed high-temperature storage tank, which is used to distribute the high-temperature thermal storage particles located therein in a fluidized state; and... The fluidized bed high-temperature storage tank is connected to the outlet of the heated fluidized bed furnace and the inlet of the fluidized bed boiler, respectively, and is used to store and transport the high-temperature heat storage particles.

5. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage according to claim 4, characterized in that, The thermal storage unit also includes a cryogenic storage tank, which is connected to the inlet of the heated fluidized bed furnace and the outlet of the fluidized bed boiler. It is used to store the cryogenic thermal storage particles after heat transfer from the fluidized bed boiler and to return the cryogenic thermal storage particles to the heated fluidized bed furnace.

6. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage according to claim 4, characterized in that, The system also includes a fan system, which comprises: A fluidizing blower is connected to the fluidized bed high-temperature storage tank and is used to fluidize the high-temperature heat storage particles in the fluidized bed high-temperature storage tank; A conveying fan, connected to the fluidized bed boiler, is used to convey low-temperature heat storage particles that have released their high-temperature heat source within the fluidized bed boiler.

7. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage according to claim 1, characterized in that, The heat storage particles include at least one of fine ash mineral sand, coal gangue grinding particles, sand and gravel fine particles, zirconium oxide fine ash particles, and alumina fine particles.

8. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage according to claim 6, characterized in that, The thermal system includes: The fluidized bed boiler; The water supply system is connected to the fluidized bed boiler; The steam drum system is connected to the fluidized bed boiler; The superheater is connected to the steam drum system via the first steam drum steam pipeline, and the superheater is connected to the steam turbine of the thermal power plant via the main steam header; The high-pressure heater is connected to the steam drum system via the second steam drum steam pipeline, and the high-pressure heater is connected to both the feedwater system and the boiler steam drum system. The fluidized bed boiler is used to receive the high-temperature thermal energy storage particles and the feedwater provided by the feedwater system, so that the thermal energy stored in the high-temperature thermal energy storage particles can be transferred to the feedwater, thereby indirectly realizing deep peak shaving of the thermal power plant.

9. A deep peak-shaving system for thermal power plants utilizing high-temperature thermal energy storage according to claim 8, characterized in that, The heat release unit further includes: An air preheater is connected to both the fluidized bed boiler and the water supply system. The water supply system is also connected to the fluidized bed boiler via an air duct to recover the heat energy of the fluidizing air in the fluidized bed boiler.

10. A method for deep peak shaving in thermal power plants utilizing high-temperature thermal energy storage, characterized in that, The method includes the following steps: The energy storage particles are filled into the heating unit, and the energy storage particles are heated by the power conversion supply unit and / or the heat transfer energy storage unit to convert electrical energy or steam heat energy into the heat storage energy of the heat storage particles. Utilize thermal storage units to store heated high-temperature energy storage particles; Stop fuel combustion in the fluidized bed boiler in the thermal system of the thermal power plant, and introduce the high-temperature energy storage particles from the thermal storage unit into the fluidized bed boiler to transfer the thermal energy stored in the thermal storage particles to the original thermal system of the thermal power plant. The thermal system is used to convert the thermal energy stored in the thermal storage particles into superheated steam with rated parameters for thermal power generation, thereby achieving deep peak shaving of the thermal power plant by utilizing high-temperature thermal energy.

Images