Reversible heat storage peak shaving system and method based on in-situ circulation in boiler

Abstract

The invention relates to the technical field of thermal power generation and large-scale energy storage, in particular to a reversible heat storage peak shaving system and method based on in-situ circulation in a boiler. The system comprises a heat storage working medium which circulates in the system, a working medium storage tank for storing the heat storage working medium and a boiler for thermal power generation. The boiler comprises a hearth, a working medium outlet of the working medium storage tank is connected with a working medium inlet of the hearth, and a working medium outlet of the hearth is connected with a working medium inlet of the working medium storage tank; and the heat storage working medium is subjected to endothermic reaction or exothermic reaction in the hearth. According to the system, the system structure can be effectively simplified, the energy conversion path of the reversible heat storage peak regulation system is shortened, and therefore the overall energy utilization efficiency of the system is improved.

Description

Technical Field

[0001] This invention relates to the fields of thermal power generation and large-scale energy storage technology, specifically to a reversible thermal storage peak-shaving system and method based on in-situ circulation within a boiler. Background Technology

[0002] With the transformation of the energy structure, renewable energy sources such as wind power and photovoltaics are being connected to the grid on a large scale. Their inherent intermittency and uncertainty require the power system to have greater flexibility and regulation capabilities. As the main regulating power source of the power system, coal-fired power generating units need to undertake more frequent and faster deep peak-shaving tasks. However, when actually performing deep peak-shaving at low loads, coal-fired units often face problems such as decreased combustion stability, lower furnace temperatures, and difficulties in controlling pollutant emissions. Therefore, energy storage technology is needed to improve the load regulation flexibility of the units.

[0003] Currently, most coupled energy storage technologies applied to thermal power units adopt "external" or "indirect" integrated solutions. For example, low-grade waste heat from the unit, such as low-parameter flue gas, or steam extracted from the turbine interstages, is used to heat the working fluid, such as molten salt, ceramics, or water, in independently set heat storage units. Alternatively, energy transfer and storage can be achieved through multiple heat exchange loops, such as a "flue gas-water-heat storage working fluid" loop.

[0004] However, the aforementioned existing technologies have certain limitations in terms of thermodynamics and operational safety. On the one hand, such "external" or "indirect" solutions typically involve long energy conversion chains and are accompanied by significant heat transfer temperature differences, leading to increased system entropy and energy loss, thus limiting the system's energy conversion efficiency. On the other hand, methods such as extracting steam from the turbine for heat storage may alter the inherent design conditions and operating characteristics of the steam-water system, introducing complex hydrodynamic safety issues and posing a potential risk to the long-term reliability of the main engine. Summary of the Invention

[0005] To address the above problems, this invention provides a reversible thermal storage peak-shaving system and method based on in-situ circulation within a boiler, which can effectively simplify the system structure and shorten the energy conversion path, thereby improving the overall energy utilization efficiency of the system.

[0006] A first aspect of the present invention provides a reversible thermal storage peak-shaving system based on in-situ circulation within a boiler. The system includes a thermal storage working fluid circulating within the system, a working fluid storage tank for storing the thermal storage working fluid, and a boiler for thermal power generation. The boiler includes a furnace, with the working fluid outlet of the working fluid storage tank connected to the working fluid inlet of the furnace, and the working fluid outlet of the furnace connected to the working fluid inlet of the working fluid storage tank; the thermal storage working fluid undergoes an endothermic or exothermic reaction within the furnace.

[0007] Optionally, the heat storage medium includes one or more of metal oxides, carbonates, and hydroxides.

[0008] Optionally, the working medium storage tank includes a first storage tank and a second storage tank. The first storage tank stores the heat storage working medium in an initial state and is connected to the furnace by a first injection device. The second storage tank stores the heat storage working medium in an energy storage state and is connected to the furnace by a second injection device.

[0009] Optionally, the boiler also includes a tail flue, which is connected to the furnace. The flue gas or fly ash produced after combustion in the furnace, as well as some of the heat storage medium, enter the tail flue.

[0010] Optionally, the reversible thermal energy storage peak shaving system further includes a gas-solid separation device and a first separation and recovery device; the gas-solid separation device is connected to the end of the tail flue and is used to collect the solid mixture containing thermal energy storage medium and fly ash in the tail flue and separate the solid mixture from the flue gas; the first separation and recovery device is connected to the solid mixture outlet of the gas-solid separation device and is used to separate the thermal energy storage medium and fly ash in the solid mixture, and the thermal energy storage medium outlet of the first separation and recovery device is connected to the thermal energy storage medium inlet of the working medium storage tank.

[0011] Optionally, the reversible thermal storage peak shaving system also includes a second separation and recovery device, which is connected to the bottom of the furnace. The second separation and recovery device separates part of the thermal storage working fluid and the slag produced by combustion in the furnace.

[0012] Optionally, the heat storage medium outlet of the first separation and recovery device includes a first heat storage medium outlet and a second heat storage medium outlet, the first heat storage medium outlet being connected to the heat storage medium inlet of the second storage tank, and the second heat storage medium outlet being connected to the heat storage medium inlet of the first storage tank; the heat storage medium outlet of the second separation and recovery device includes a third heat storage medium outlet and a fourth heat storage medium outlet, the third heat storage medium outlet being connected to the heat storage medium inlet of the second storage tank, and the fourth heat storage medium outlet being connected to the heat storage medium inlet of the first storage tank.

[0013] Optionally, the reversible thermal storage peak-shaving system also includes a control unit, which is communicatively connected to the boiler to receive load signals and main steam pressure signals from the boiler.

[0014] A second aspect of the present invention provides a reversible thermal energy storage peak-shaving method based on in-situ circulation within a boiler, for use in the aforementioned reversible thermal energy storage peak-shaving system, comprising the following steps: The judgment step is to determine whether the power grid is in a low-consumption period or a high-consumption period. In the thermal storage step, when the judgment step determines that the power grid is in a low electricity demand period, the thermal storage medium in the initial state in the first storage tank is injected into the furnace to carry out an endothermic reaction to transform it into an energy storage state. The thermal storage medium in the energy storage state is then separated and transferred to the second storage tank. In the heat release step, when the judgment step determines that the power grid is in a peak electricity consumption period, the heat storage medium in the energy storage state in the second storage tank is injected into the furnace to carry out a heat release reaction to transform it into the initial state. The heat storage medium in the initial state is then separated and transferred to the first storage tank. Repeat the steps, and repeat the heat storage or heat release steps based on the real-time judgment results of the judgment steps.

[0015] Optionally, during the heat storage or heat release step, the heat storage medium that has completed the endothermic or exothermic reaction is automatically guided to the second storage tank corresponding to the energy storage state or the first storage tank corresponding to the initial state.

[0016] The reversible thermal storage peak-shaving system provided by this invention directly utilizes the high-temperature environment of the boiler itself as an in-situ reactor. A reversible thermal storage medium is introduced into the boiler furnace, allowing it to directly absorb or release heat within the furnace. This significantly shortens the energy conversion path and reduces losses caused by intermediate heat exchange stages, achieving efficient energy storage and in-situ utilization, thereby effectively improving the overall energy efficiency of the system. Simultaneously, this system operates relatively independently from the steam-water unit of the thermal power plant, effectively reducing hydrodynamic safety risks and ensuring long-term stable operation of the unit.

[0017] When the power grid is in a low-load period and the unit needs to perform low-load peak shaving, this system uses the heat storage medium to carry out an endothermic reaction in the furnace, absorbing the excess heat in the boiler. This can directly and quickly reduce the effective heat output of the boiler, thereby extending the theoretical peak load lower limit of the unit to a lower level. At the same time, the heat storage medium carrying heat after the reaction releases sensible heat when flowing through the heating surface at the tail of the boiler, which can effectively compensate for the steam temperature. This helps to alleviate the impact of the decrease in flue gas temperature at the furnace outlet on the main steam parameters under low-load conditions, thereby achieving deep peak shaving while further maintaining the unit's operational stability and economy.

[0018] In addition, after the heat storage medium that completes energy storage in the high-temperature zone of the furnace through physicochemical reaction is transferred from the furnace, even if it is not separated and purified from the flue gas, fly ash or slag, the energy stored in the heat storage medium, excluding sensible heat, can still be effectively maintained. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a reversible thermal storage peak-shaving system provided in the first embodiment of the present invention.

[0020] Figure 2 This is a flowchart of a reversible thermal energy storage peak shaving method provided in the second embodiment of the present invention.

[0021] Figure reference numerals: 100-Reversible thermal energy storage peak-shaving system, 100A-Boiler, 100B-First injection device, 100C-Second injection device, 1-First storage tank, 2-First gate valve, 3-First transfer pump, 4-First ball valve, 5-Second storage tank, 6-Second gate valve, 7-Second transfer pump, 8-Second ball valve, 9-First injection nozzle, 10-Second injection nozzle, 11-Furnace, 12-Screen-type superheater, 13-High-temperature superheater, 14-Low-temperature superheater, 15-Tail flue, 16-Economizer, 17-Gas-solid Separation device, 18-First separation and recovery device, 18A-First thermal storage medium outlet, 18B-Second thermal storage medium outlet, 19-Second separation and recovery device, 19A-Third thermal storage medium outlet, 19B-Fourth thermal storage medium outlet, 20-Third gate valve, 21-Third transfer pump, 22-Third ball valve, 23-Fourth gate valve, 24-Fourth transfer pump, 25-Fourth ball valve, 26-Fifth gate valve, 27-Fifth transfer pump, 28-Fifth ball valve, 29-Sixth gate valve, 30-Sixth transfer pump, 31-Sixth ball valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] <First Implementation Method> This embodiment provides a reversible thermal storage peak-shaving system 100 based on in-situ circulation within a boiler. The system includes a thermal storage working fluid circulating within the system, a working fluid storage tank for storing the thermal storage working fluid, and a boiler 100A for thermal power generation. The boiler 100A includes a furnace 11. The working fluid outlet of the working fluid storage tank is connected to the working fluid inlet of the furnace 11, and the working fluid outlet of the furnace 11 is connected to the working fluid inlet of the working fluid storage tank. The thermal storage working fluid undergoes endothermic or exothermic reactions within the furnace 11.

[0024] In this embodiment, the reversible thermal storage peak-shaving system 100 has two operating modes: thermal storage mode and heat release mode, which can be flexibly switched according to the grid load demand. Specifically, when the grid is in a low-consumption period and the unit needs to reduce load, the thermal storage mode of the reversible thermal storage peak-shaving system 100 is activated, allowing the thermal storage medium to enter the furnace 11 for an endothermic reaction, absorbing excess heat energy in the boiler 100A and converting it into chemical or physical energy for storage. Simultaneously, this allows the unit to quickly and stably reduce to the target low-consumption load. When the grid is in a high-consumption period and the unit needs to rapidly increase load, the heat release mode of the reversible thermal storage peak-shaving system 100 is activated, allowing the thermal storage medium to enter the furnace 11 for an exothermic reaction. This rapidly releases the stored chemical or physical energy back to the furnace 11 as heat energy, enabling the unit to quickly climb to the target peak load in a short time, responding to the grid's peak-shaving demand.

[0025] Boiler 100A, as the main power generation equipment in thermal power generation, has a high-temperature environment inside its furnace 11 caused by fuel combustion. In this embodiment, the furnace 11 is not only the place where fuel combustion releases heat energy, but also serves as an in-situ reactor for reversible endothermic or exothermic reactions of the heat storage medium. By injecting the heat storage medium into the furnace 11 of boiler 100A, on the one hand, the heat storage medium can directly absorb excess heat energy in the furnace 11 to undergo an endothermic reaction, storing energy in the form of chemical or physical energy; on the other hand, the heat storage medium can directly release energy in the furnace 11, rapidly increasing the heat load of boiler 100A. The above energy conversion process does not require additional intermediate heat exchange links or independent reactors, which not only shortens the energy conversion path and reduces entropy increase and energy loss, thereby effectively improving energy utilization efficiency, but also simplifies the system structure and reduces the equipment investment cost and floor space of the reversible heat storage peak-shaving system 100. In addition, the reversible thermal storage peak shaving system 100 can extend the theoretical peak load lower limit of thermal power units to a lower level and provide a huge thermal power supplement in a short period of time, so as to achieve rapid and large-scale adjustment of thermal load.

[0026] In this embodiment, the heat storage medium circulates within the system and can absorb and release heat through reversible physical or chemical reactions, serving as a carrier for energy storage and conversion. The specific form of the heat storage medium can be granular to facilitate its circulation and efficient heat absorption or release within the system. In this embodiment, the heat storage medium includes one or more of metal oxides, carbonates, and hydroxides. Specifically, the metal oxides can be iron oxide (Fe2O3 / Fe3O4) or manganese oxide (Mn2O3 / Mn3O4), which can undergo reduction / oxidation reactions at high temperatures; the carbonates can be calcium carbonate (CaCO3), which can undergo decomposition / synthesis reactions; and the hydroxides can be calcium hydroxide (Ca(OH)2), which can undergo dehydration / hydration reactions. The heat storage medium made from the above materials has two energy states: an initial state and a stored state. Under the high-temperature environment within the furnace 11, the initial state heat storage medium absorbs heat and transforms into the stored state; under appropriate conditions, such as a specific temperature and atmosphere, the stored state heat storage medium releases heat and returns to its initial state. In other embodiments, other types of heat storage media can also be used, as long as they can stably complete the heat absorption and heat release conversion in the high-temperature environment of the furnace 11. No specific restrictions are imposed here.

[0027] To enable rapid storage and release of energy within the furnace 11, this embodiment utilizes separate storage tanks for the initial and energy storage states of the thermal storage medium. Specifically, the storage tanks include a first tank 1 and a second tank 5. The first tank 1 stores the initial state of the thermal storage medium, while the second tank 5 stores the energy storage state. By setting up separate first tank 1 and second tank 5 to store the initial and energy storage states of the thermal storage medium respectively, the type of thermal storage medium injected into the furnace 11 can be flexibly controlled according to grid demand, thereby enabling rapid switching between thermal storage and heat release modes and achieving bidirectional regulation of the unit load.

[0028] refer to Figure 1The first storage tank 1 is connected to the furnace 11 via a first injection device 100B, and the second storage tank 5 is connected to the furnace 11 via a second injection device 100C. Along the direction from the working medium storage tank to the furnace 11, the first injection device 100B is sequentially equipped with a first gate valve 2, a first transfer pump 3, and a first ball valve 4; the second injection device 100C is sequentially equipped with a second gate valve 6, a second transfer pump 7, and a second ball valve 8; and the connection points between the first injection device 100B and the second injection device 100C and the furnace 11 are respectively equipped with a first injection nozzle 9 and a second injection nozzle 10. The transfer pump provides power for the transport of the heat storage working medium, and the aforementioned valve group is used to control the opening and closing of the transport path. The first injection nozzle 9 and the second injection nozzle 10 can be wear-resistant and high-temperature resistant tapered nozzles, which can uniformly inject the heat storage working medium into the main combustion zone of the furnace 11, allowing it to fully mix and exchange heat with the high-temperature flue gas. In other embodiments, the working medium conveying structure and specific equipment type between the working medium storage tank and the furnace 11 are not limited to the above forms, as long as the heat storage working medium can be stably conveyed and uniformly injected into the furnace 11, no specific restrictions are imposed here.

[0029] In this embodiment, boiler 100A also includes a tail flue 15, as shown in the reference. Figure 1 The tail flue 15 is connected to the furnace 11. The flue gas, solid fly ash, and some of the heat storage working fluid particles produced by combustion in the furnace 11 all enter the tail flue 15. On the one hand, the flue gas, fly ash, or other products produced in the furnace 11 are introduced into other pre-designed devices through the tail flue 15; on the other hand, the tail flue 15 is used as a recovery path for the heat storage working fluid, further improving the utilization efficiency of the devices in the system and simplifying the system structure.

[0030] In the heat storage mode, to suppress the rate of reverse exothermic reaction of the heat storage medium generated by the endothermic reaction in the furnace 11 upon entering the tail flue 15, in this embodiment, a screen-type superheater 12, a high-temperature superheater 13, and a low-temperature superheater 14 are sequentially installed in the channel between the furnace 11 and the tail flue 15 along the flow direction. These superheaters rapidly absorb the heat carried by the flue gas, fly ash, and heat storage medium, forming a temperature drop zone. This allows the heat storage medium to be rapidly cooled after leaving the furnace 11, thereby maintaining its converted chemical energy and ensuring the energy storage efficiency of the reversible heat storage peak-shaving system 100. Simultaneously, in the exothermic mode, the screen-type superheater 12, the high-temperature superheater 13, and the low-temperature superheater 14 can further absorb the heat released by the heat storage medium within the boiler 100A, thereby achieving a rapid increase in unit load. (Reference) Figure 1An economizer 16 is also installed in the tail flue 15 to further absorb the waste heat of the flue gas to heat the feedwater of the boiler 100A, while reducing the temperature of the flue gas and the heat storage medium it carries, and further forming a low-temperature environment that can suppress the reverse exothermic reaction of the energy storage medium, so as to ensure the effective storage of energy.

[0031] In this embodiment, when the reversible thermal storage peak-shaving system 100 is in thermal storage mode, the initial-state thermal storage medium absorbs heat and undergoes a physicochemical reaction within the furnace 11, storing the excess energy in the furnace as physical or chemical energy, thus transforming it from the initial state to the energy storage state. Even if the thermal storage medium enters the tail flue 15 with the flue gas or fly ash generated by combustion within the furnace 11 and undergoes sensible heat cooling, the physical or chemical energy stored through the physicochemical reaction remains stably maintained in the energy storage state of the thermal storage medium, and this stored energy does not significantly decrease with temperature drop. Until the reversible thermal storage peak-shaving system 100 switches to exothermic mode, the energy storage medium in the energy storage state is reinjected into the furnace 11, and under specific reaction conditions, the physical or chemical energy stored within it is reconverted and released as heat energy, simultaneously restoring it from the thermal storage state to the initial state, thereby completing energy storage peak-shaving. When the power grid is in a low-load period and the unit needs to perform low-load peak shaving, the reversible thermal storage peak shaving system 100 utilizes the thermal storage medium to carry out an endothermic reaction in the furnace 11, absorbing the excess heat in the boiler 100A. This can directly and quickly reduce the effective heat output of the boiler 100A, thereby extending the theoretical peak load lower limit of the unit to a lower level. At the same time, the thermal storage medium carrying heat after the reaction releases sensible heat when flowing through the tail heating surface of the boiler 100A, which can effectively compensate for the steam temperature. This helps to alleviate the impact of the drop in the outlet flue gas temperature of the furnace 11 on the main steam parameters under low-load conditions, thereby achieving deep peak shaving while further maintaining the operational stability and economy of the unit.

[0032] It is worth noting that in this embodiment, when the unit needs to perform low-load peak shaving, the heat storage medium is injected into the furnace 11. On the one hand, the heat storage medium absorbs the excess heat in the furnace 11 to complete the transformation from the initial state to the energy storage state, effectively reducing the effective steam output of the boiler 100A, thereby cooperating with the unit to achieve deep load reduction and peak shaving. On the other hand, when the energy storage medium carrying high-temperature sensible heat flows through the area where the screen-type superheater 12, high-temperature superheater 13, and low-temperature superheater 14 are located between the outlet of the furnace 11 and the inlet of the tail flue 15, it can release the sensible heat it carries, continuously performing heat exchange compensation in the above-mentioned areas, thereby effectively alleviating the problem of the steam temperature parameter drop caused by the low outlet temperature of the furnace 11 under low-load conditions, and thus maintaining the stability of the main steam parameters at the turbine inlet, ensuring the operational stability of the unit under low load. In this process, after the thermal storage medium undergoes sensible cooling in the aforementioned region, the physical or chemical energy stored within it through physicochemical reactions remains stable and will not be significantly lost as its physical temperature decreases, thus ensuring efficient energy storage.

[0033] In order to recover the heat storage medium from the flue gas and fly ash in the tail flue 15, in this embodiment, the reversible heat storage peak-shaving system 100 further includes a gas-solid separation device 17 and a first separation and recovery device 18. The gas-solid separation device 17, which can be an electrostatic precipitator, a bag filter, or a cyclone separator, is located at the end of the tail flue 15 and is used to capture and separate the solid mixture containing the heat storage medium and fly ash from the flue gas. The first separation and recovery device 18 is connected to the outlet of the solid mixture of the gas-solid separation device 17 and is used to further separate the heat storage medium from the fly ash in the solid mixture. Based on the differences in the physical properties of the heat storage medium and the fly ash of boiler 100A, such as magnetic properties, density, inertia, or electrical properties, the separation and recovery device includes one or more combinations of magnetic separators, inertial separators, cyclone separators, and electrostatic separators. If the heat storage medium is an iron-based oxide, a multi-stage magnetic separator can be used to separate them by utilizing their magnetic differences. If the density difference between the heat storage medium and fly ash is significant, an inertial separator or cyclone separator can be used. If the electrical properties of the heat storage medium and fly ash are significantly different, an electrostatic separator can be used. If the particle size difference between the heat storage medium and fly ash is significant, a sieve or air classifier can be used, and the separated heat storage medium is guided to the working medium storage tank.

[0034] Because some of the larger-sized or larger-mass heat storage medium that completes the endothermic or exothermic reaction within the furnace 11 fails to enter the tail flue 15 with the fly ash and flue gas, it instead settles to the bottom of the furnace 11 by gravity along with the slag formed during combustion. To recover and recycle this portion of the heat storage medium, in this embodiment, the reversible heat storage peak-shaving system 100 also includes a second separation and recovery device 19, connected to the bottom of the furnace 11, used to separate the portion of the heat storage medium settled at the bottom of the furnace 11 from the slag produced during combustion. The second separation and recovery device 19 can also utilize the differences in physical properties such as magnetism, density, inertia, or electrical properties between the heat storage medium and the slag to separate the heat storage medium from the slag. The separated heat storage medium is also guided to a working medium storage tank. In other embodiments, other separation equipment is used for separating the heat storage medium from the fly ash and slag; specific limitations are not specified here.

[0035] Since the thermal storage medium in this embodiment includes an initial state and an energy storage state, in order to enable the thermal storage medium in both states to be respectively transported to the corresponding first or second working medium storage tank, in this embodiment, the thermal storage medium outlet of the first separation and recovery device 18 includes a first thermal storage medium outlet 18A connected to the thermal storage medium inlet of the second storage tank 5, and a second thermal storage medium outlet 18B connected to the thermal storage medium inlet of the first storage tank 1; the thermal storage medium outlet of the second separation and recovery device 19 includes a third thermal storage medium outlet 19A connected to the thermal storage medium inlet of the second storage tank 5, and a fourth thermal storage medium outlet 19B connected to the thermal storage medium inlet of the first storage tank 1. (Reference) Figure 1 A third gate valve 20, a third transfer pump 21, and a third ball valve 22 are sequentially installed on the connecting pipe from the first thermal storage medium outlet 18A to the thermal storage medium inlet of the second storage tank 5; a fourth gate valve 23, a fourth transfer pump 24, and a fourth ball valve 25 are sequentially installed on the connecting pipe from the second thermal storage medium outlet 18B to the thermal storage medium inlet of the first storage tank 1; a fifth gate valve 26, a fifth transfer pump 27, and a fifth ball valve 28 are sequentially installed on the connecting pipe from the third thermal storage medium outlet 19A to the thermal storage medium inlet of the second storage tank 5; and a sixth gate valve 29, a sixth transfer pump 30, and a sixth ball valve 31 are sequentially installed on the connecting pipe from the fourth thermal storage medium outlet 19B to the thermal storage medium inlet of the first storage tank 1. By switching the valve group as described above, the initial state thermal storage medium generated after the exothermic reaction is sent back to the first storage tank 1, and the energy storage medium generated after the endothermic reaction is sent back to the second storage tank 5, thereby completing the closed-loop operation of the reversible thermal storage peak-shaving system 100 and the recycling of the thermal storage medium.

[0036] In other embodiments, the thermal storage medium separated and recovered by the first separation and recovery device 18 and the second separation and recovery device 19 is not limited to recycling within the reversible thermal storage and peak-shaving system 100 in this embodiment. For example, the thermal storage medium in its energy storage state can be used as an independent high-temperature heat source for other industrial processes or heating systems that require heat energy. Simultaneously, the thermal storage medium in its initial state can also complete heat absorption and energy storage at other suitable heat source locations. No specific limitations are made here regarding the utilization method of the thermal storage medium.

[0037] In this embodiment, the reversible thermal storage peak shaving system 100 also includes a control unit (not shown in the figure). The control unit is communicatively connected to the boiler 100A and receives the load signal and main steam pressure signal of the boiler 100A. It is used to control the reversible thermal storage peak shaving system 100 to switch between thermal storage mode and thermal release mode based on grid demand, and to adjust the injection rate and injection amount of thermal storage working fluid into the furnace 11, as well as the start and stop of the gas-solid separation device 17, the first separation and recovery device 18 and the second separation and recovery device 19.

[0038] <Second Implementation Method> This embodiment provides a reversible thermal energy storage peak-shaving system 100 based on in-situ circulation within a boiler 100A, applied to the reversible thermal energy storage peak-shaving system 100 provided in the first embodiment, with reference to... Figure 2 The method includes the following steps: a judgment step S1, a heat storage step S2, a heat release step S3, and a repeating step S4. Specifically: Judgment Step S1: The reversible thermal storage peak-shaving system 100 determines whether the power grid is in a low-consumption or high-consumption period based on the received load signal from the boiler 100A, main steam pressure signal, etc. The judgment basis is not limited to the above signals, but can also be combined with power grid dispatch instructions, as long as the power grid load status can be accurately identified.

[0039] Thermal storage step S2: When it is determined that the power grid is in a low-demand period, the first injection device 100B injects the initial-state thermal storage medium from the first storage tank 1 into the furnace 11. The thermal storage medium undergoes an endothermic reaction in the high-temperature environment of the furnace 11, transforming into an energy storage state. Part of the energy storage medium after the reaction enters the tail flue duct 15 with the flue gas, is captured by the gas-solid separation device 17, and is sent to the first separation and recovery device 18 for separation from fly ash; the other part is discharged from the bottom of the furnace 11 with the slag and sent to the second separation and recovery device 19 for separation from the slag. The separated energy storage medium is transferred to the second storage tank 5 for storage.

[0040] Heat release step S3: When it is determined that the power grid is in a peak electricity consumption period, the second injection device 100C injects the energy-storing thermal medium in the second storage tank 5 into the furnace 11. The energy-storing thermal medium undergoes an exothermic reaction in the high-temperature oxygen-rich environment of the furnace 11, transforming into its initial state. The released heat directly supplements the heat load of the boiler 100A. The initial state thermal medium after the reaction is also collected and separated by the gas-solid separation device 17, the first separation and recovery device 18, and the second separation and recovery device 19, and then transferred to the first storage tank 1 for storage.

[0041] Repeat step S4: Based on the real-time judgment result of judgment step S1, repeat the thermal storage step S2 or the heat release step S3 to realize the recycling of thermal storage medium and the dynamic adjustment of grid load.

[0042] In the heat storage step S2 or the heat release step S3, the heat storage medium that has completed the endothermic or exothermic reaction can be automatically guided to the corresponding energy storage state of the second storage tank 5 or the corresponding initial state of the first storage tank 1 without manual intervention. This ensures that the heat storage medium can be recycled in the reversible heat storage and peak shaving system 100, thereby maintaining the continuous and stable operation of the system as a whole and improving its automation level. Specifically, according to the heat storage mode and heat release mode currently executed by the reversible heat storage and peak shaving system 100, the control unit can control the opening and closing of the valve group between the first separation and recovery device 18, the second separation and recovery device 19 and the first storage tank 1 and the second storage tank 5, so that the heat storage medium in the initial state or energy storage state can be automatically guided to the corresponding second storage tank 5 or first storage tank 1.

[0043] In this embodiment, the specific operation procedure of the reversible thermal energy storage peak shaving system 100 is as follows: When the control unit detects a load reduction command from the unit, the reversible thermal storage peak-shaving system 100 automatically enters the thermal storage mode. The control unit then controls the opening of the first gate valve 2 and the first ball valve 4, the closing of the second gate valve 6 and the second ball valve 8, the closing of the fourth gate valve 23 and the fourth ball valve 25, the opening of the third gate valve 20 and the third ball valve 22, the closing of the sixth gate valve 29 and the sixth ball valve 31, and the opening of the fifth gate valve 26 and the fifth ball valve 28. The first transfer pump 3 starts, injecting the initial state thermal storage medium from the first storage tank 1 into the high-temperature zone of the furnace 11 through the first injection nozzle 9. The initial state thermal storage medium undergoes an endothermic reaction within the furnace 11, effectively recovering and preserving the heat energy within the boiler 100A, assisting in a smooth decrease in the main steam pressure, and enabling the unit to quickly and stably reduce to the target low load.

[0044] After the endothermic reaction, a portion of the heat storage medium generated enters the tail flue 15 along with the fly ash, where it is captured by the gas-solid separator 17 and enters the first separation and recovery device 18 downstream of the gas-solid separator 17. The other portion of the heat storage medium is discharged from the bottom of the furnace 11 along with the slag and enters the second separation and recovery device 19 downstream of the furnace 11. The energy storage heat storage medium separated by the first and second separation and recovery devices 18 and 19 is then transported to the second storage tank 5 by the third and fifth transfer pumps 21 and 27 for storage, completing the transformation of the heat storage medium's form and energy storage.

[0045] After the control unit detects the unit's load increase command, it automatically enters the heat release mode. The control unit then controls the second gate valve 6 and the second ball valve 8 to open, the first gate valve 2 and the first ball valve 4 to close, the third gate valve 20 and the third ball valve 22 to close, the fourth gate valve 23 and the fourth ball valve 25 to open, the fifth gate valve 26 and the fifth ball valve 28 to close, and the sixth gate valve 29 and the sixth ball valve 31 to open. The second transfer pump 7 starts, injecting the energy-storing heat storage medium from the second storage tank 5 into the high-temperature, oxygen-rich zone of the furnace 11 inside the boiler 100A through the second injection nozzle 10. The energy-storing heat storage medium undergoes an exothermic reaction in the high-temperature, oxygen-rich environment, instantly releasing a large amount of energy, increasing the steam production rate of the evaporation unit connected to the boiler 100A, and enabling the unit to quickly respond to load increases.

[0046] After the exothermic reaction, a portion of the initial thermal storage medium generated enters the tail flue 15 along with the fly ash, where it is again captured by the gas-solid separator 17 and enters the first separation and recovery device 18 downstream of the gas-solid separator 17 along with the fly ash. The other portion of the thermal storage medium is discharged from the bottom of the furnace 11 along with the slag and enters the second separation and recovery device 19 downstream of the furnace 11. The initial thermal storage medium separated by the first and second separation and recovery devices 18 and 19 is transported to the first storage tank 1 by the fourth transfer pump 24 and the sixth transfer pump 30 for storage, completing the transformation of the thermal storage medium's form and the release of energy.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A reversible thermal storage peak-shaving system based on in-situ circulation within a boiler, characterized in that, include: The heat storage medium circulates within the system. Working fluid storage tank, for storing the heat storage working fluid; Boilers used for thermal power generation include: The furnace chamber has a working fluid outlet connected to the working fluid inlet of the working fluid storage tank, and the working fluid outlet of the furnace chamber is connected to the working fluid inlet of the working fluid storage tank. The heat storage medium undergoes an endothermic or exothermic reaction within the furnace.

2. The reversible thermal storage peak-shaving system as described in claim 1, characterized in that, The heat storage medium includes one or more of metal oxides, carbonates, and hydroxides.

3. The reversible thermal storage peak-shaving system as described in claim 1, characterized in that, The working fluid storage tank includes: The first storage tank stores the heat storage medium in its initial state, and the first storage tank is connected to the furnace by a first injection device. The second storage tank stores the heat storage medium in an energy storage state, and the second storage tank is connected to the furnace by a second injection device.

4. The reversible thermal storage peak-shaving system as described in claim 3, characterized in that, The boiler also includes: The tail flue is connected to the furnace, and the flue gas or fly ash generated after combustion in the furnace, as well as some of the heat storage medium, enter the tail flue.

5. The reversible thermal storage peak-shaving system as described in claim 4, characterized in that, Also includes: A gas-solid separation device is connected to the end of the tail flue to capture the solid mixture containing the heat storage medium and fly ash in the tail flue and separate it from the flue gas. The first separation and recovery device is connected to the solid mixture outlet of the gas-solid separation device to separate the heat storage medium and fly ash from the solid mixture; the heat storage medium outlet of the first separation and recovery device is connected to the heat storage medium inlet of the working medium storage tank.

6. The reversible thermal storage peak-shaving system as described in claim 5, characterized in that, Also includes: The second separation and recovery device is connected to the bottom of the furnace, and a portion of the heat storage medium and the slag produced by combustion in the furnace are separated by the second separation and recovery device.

7. The reversible thermal storage peak-shaving system as described in claim 6, characterized in that, The heat storage medium outlet of the first separation and recovery device includes: The outlet of the first thermal storage medium is connected to the inlet of the second thermal storage tank; The second thermal storage medium outlet is connected to the thermal storage medium inlet of the first storage tank; The heat storage medium outlet of the second separation and recovery device includes: The third thermal storage medium outlet is connected to the thermal storage medium inlet of the second storage tank; The fourth thermal storage medium outlet is connected to the thermal storage medium inlet of the first storage tank.

8. The reversible thermal storage peak-shaving system as described in claim 1, characterized in that, It also includes a control unit, which is communicatively connected to the boiler and receives the boiler's load signal and main steam pressure signal.

9. A reversible thermal energy storage peak-shaving method based on in-situ circulation within a boiler, used in the reversible thermal energy storage peak-shaving system as described in any one of claims 1-8, characterized in that, Includes the following steps: The judgment step is to determine whether the power grid is in a low-consumption period or a high-consumption period. In the heat storage step, when the judgment step determines that the power grid is in a low electricity consumption period, the heat storage medium in the initial state in the first storage tank is injected into the furnace to carry out an endothermic reaction to transform it into an energy storage state, and the heat storage medium in the energy storage state is separated and transferred to the second storage tank. In the heat release step, when the judgment step determines that the power grid is in a peak electricity consumption period, the heat storage medium in the energy storage state in the second storage tank is injected into the furnace to carry out an exothermic reaction to transform it into an initial state, and the heat storage medium in the initial state is separated and transferred to the first storage tank. Repeat the steps, and repeat the heat storage step or the heat release step based on the real-time judgment result of the judgment step.

10. The reversible thermal storage peak shaving method as described in claim 9, characterized in that, In the heat storage step or the heat release step, the heat storage medium that has completed the endothermic or exothermic reaction is automatically guided to the second storage tank corresponding to the energy storage state or the first storage tank corresponding to the initial state.

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