Coal-fired power plant flue gas and single-tank solid heat storage coupled peak shaving system

Abstract

The application relates to the technical field of thermal power flexibility reconstruction, and discloses a coal-fired power plant flue gas and single-tank solid heat storage coupling peak regulation system, which comprises a solid heat accumulator, an electric heater, a heat exchanger, a fan and a power supply which are connected through pipelines and in fluid communication. The single-tank solid heat storage is used to replace the traditional double-tank molten salt heat storage, so that the system structure is greatly simplified, and the investment cost is reduced. Meanwhile, the flue gas with certain pressure and flow rate discharged from the coal-fired power plant is ingeniously used as the heat transfer medium of the system, so that the peak regulation capacity of the coal-fired power plant is improved, the energy is efficiently utilized, and the system is more economical and feasible. Through the heat storage by using electric heating, the new energy wind power and light power can be consumed, the energy circulation efficiency is improved, the heat storage temperature of the heat storage medium can be improved, and the application scenarios of the heat storage system are enriched.

Description

Technical Field

[0001] This application relates to the field of thermal power plant flexibility retrofit technology, and in particular to a peak-shaving system that couples flue gas from a coal-fired power plant with a single-tank solid thermal storage system. Background Technology

[0002] At this critical juncture of profound global energy structure transformation, the flexible transformation of thermal power plants has become a core issue for overcoming development bottlenecks in the energy sector. With the installed capacity of renewable energy sources such as wind and solar power expanding at an average annual rate of over 20%, the inherent intermittency, volatility, and anti-peak-shaving characteristics of these sources are increasingly at odds with the safe and stable operation of the power grid. Taking Northwest my country as an example, during certain periods, renewable energy generation can account for more than 60% of the instantaneous load of the entire grid. However, due to insufficient accuracy in wind and solar power output forecasting, the curtailment rate remains in the range of 8%-12%, resulting in a serious waste of clean energy.

[0003] Against this backdrop, the flexible retrofitting of thermal power plants, through technological upgrades, achieves "millisecond-level response" and "wide load regulation" in unit power generation, becoming a key support for building a new power system. Specifically, the retrofitted coal-fired power plants can operate stably within a 15%-100% rated load range, expanding the regulation range by more than three times compared to traditional units. This allows for deep peak shaving to create space for renewable energy generation and rapid peak power supply during extreme weather conditions, forming a synergistic mechanism of multi-energy complementarity between wind, solar, thermal, and energy storage. Taking a 600MW unit retrofitting project in Shandong as an example, after its peak shaving capacity was increased by 200MW, the annual renewable energy consumption increased by 520 million kWh, equivalent to reducing coal consumption by 160,000 tons and carbon dioxide emissions by 420,000 tons. This positioning as a "supportive regulating power source" not only ensures the security of power supply during the energy transition period but also provides a replicable technological paradigm for the stable operation of high-proportion renewable energy systems.

[0004] Among various thermal power plant flexibility retrofit technologies, the dual-tank molten salt thermal storage scheme was once highly favored. This scheme uses two molten salt tanks to store high-temperature molten salt and low-temperature molten salt respectively, utilizing the high specific heat capacity of molten salt to store heat during periods of low electricity load and release heat to generate electricity during peak periods. However, the dual-tank molten salt thermal storage scheme also has some limitations that cannot be ignored. First, the dual-tank molten salt thermal storage system has a complex structure, requiring the construction of two large molten salt tanks and related complex piping systems, which makes its investment cost high and construction period long. Second, the operation and maintenance costs are high. During operation, the dual-tank molten salt thermal storage scheme requires the installation of facilities such as electric heat tracing to prevent molten salt from solidifying, which greatly increases operating costs. Molten salt is highly corrosive, which will cause wear and tear on the thermal storage tanks, pipelines, and other equipment, requiring regular equipment maintenance and replacement, increasing maintenance costs.

[0005] Therefore, it is crucial to develop a simplified, more economical, and feasible technology solution for the flexible retrofitting of thermal power plants. Utility Model Content

[0006] The purpose of this application is to provide a peak-shaving system that couples flue gas from a coal-fired power plant with a single-tank solid thermal storage system. By using a single-tank solid thermal storage system instead of the traditional two-tank molten salt thermal storage system, the system structure is greatly simplified and investment costs are reduced. Simultaneously, by cleverly utilizing the flue gas discharged from the coal-fired power plant, which has a certain pressure and flow rate, as the system's heat transfer medium, not only is the peak-shaving capacity of the coal-fired power plant improved, but also the efficient utilization of energy is achieved, making it more economical and feasible.

[0007] The embodiments of this application disclose a peak-shaving system for coupling flue gas and single-tank solid thermal storage in a coal-fired power plant, comprising: a solid thermal accumulator, an electric heater, a heat exchanger, a fan, and a power supply connected by pipelines and in fluid communication;

[0008] The solid heat accumulator is filled with a solid heat storage medium for storing thermal energy.

[0009] The electric heater is used to heat the heat transfer medium in heat storage mode;

[0010] The heat exchanger is used to extract heat from the heat transfer medium in heat release mode and transfer the heat to the working fluid that needs to be heated.

[0011] The fan is used to provide power for fluid circulation within the system in heat storage mode;

[0012] The power supply is used to supply power to the electric heater in heat storage mode;

[0013] The bottom inlet of the solid heat accumulator is connected to the flue gas outlet of the coal-fired power plant through a first shut-off valve. The bottom outlet of the solid heat accumulator is connected to the inlet of the blower through a second shut-off valve. The outlet of the blower is connected to the inlet of the electric heater. The outlet of the electric heater is connected to the top port of the solid heat accumulator through a third shut-off valve. The top port of the solid heat accumulator is connected to the inlet of the heat exchanger through a fourth shut-off valve.

[0014] In another preferred embodiment, the coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage includes: a thermal storage circuit and a heat release circuit;

[0015] The heat storage circuit includes: a first shut-off valve, a solid heat accumulator, a second shut-off valve, a fan, an electric heater, a third shut-off valve, and a power supply;

[0016] The heat release circuit includes: a first shut-off valve, a solid heat accumulator, a fourth shut-off valve, and a heat exchanger.

[0017] In another preferred embodiment, in the heat storage mode, the fourth shut-off valve of the heat release circuit is closed; in the heat release mode, the second and third shut-off valves of the heat storage circuit are closed.

[0018] In another preferred embodiment, in the heat storage mode, the heat transfer medium is air and / or flue gas discharged from the flue gas outlet of a coal-fired power plant; in the heat release mode, the heat transfer medium is flue gas discharged from the flue gas outlet of a coal-fired power plant.

[0019] In another preferred embodiment, the solid heat accumulator is provided with flow dividers at the top and bottom, and the solid heat storage medium is in the middle.

[0020] In another preferred embodiment, the solid heat storage medium includes concrete, rock, and / or metal spheres.

[0021] In another preferred embodiment, a mixing shut-off valve is further included, connected between the outlet of the heat exchanger and the flue gas outlet.

[0022] In another preferred embodiment, the mixing shut-off valve is used to open when the inlet temperature of the cold side medium of the heat exchanger is higher than a preset threshold, so as to mix the high-temperature flue gas with the low-temperature flue gas before it enters the solid heat accumulator.

[0023] In another preferred embodiment, the working medium to be heated is water, and the heat exchanger is used to heat the water into steam.

[0024] In another preferred embodiment, the power source is the surplus electrical energy generated by coal-fired power plants and new energy generator units during peak shaving.

[0025] It should be understood that, within the scope of this application, the various technical features described above and those specifically described below (e.g., in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be elaborated upon here.

[0026] The main differences and effects of the implementation method of this application compared with the prior art are as follows:

[0027] This application discloses a peak-shaving system that couples flue gas from a coal-fired power plant with a single-tank solid thermal storage system. By using a single-tank solid thermal storage system instead of the traditional two-tank molten salt thermal storage system, the system structure is greatly simplified, and investment costs are reduced. Simultaneously, the system cleverly utilizes the flue gas discharged from the coal-fired power plant, which has a certain pressure and flow rate, as the heat transfer medium. This not only improves the peak-shaving capacity of the coal-fired power plant but also achieves efficient energy utilization, making it more economical and feasible.

[0028] Furthermore, in this coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage, gas is used as the heat transfer medium, eliminating the need for facilities such as electric heat tracing, thus reducing operating costs.

[0029] Furthermore, in the heat release mode, the pressure and flow rate of the flue gas discharged from the coal-fired power plant are cleverly utilized, eliminating the need for additional fans to drive heat transfer, avoiding fan power consumption, significantly reducing energy consumption in the solid heat storage process, and further reducing operating costs.

[0030] Furthermore, in the heat storage mode, the flue gas emitted from coal-fired power plants, which has a certain temperature, can be used to further utilize its own heat compared to the low-temperature air, which is more conducive to saving energy.

[0031] Furthermore, during the heat storage phase, the shut-off valve of the heat release circuit is closed; during the heat release phase, the shut-off valve of the heat storage circuit is closed. This prevents heat from flowing back between the heat storage circuit and the heat release circuit, avoids heat loss and mutual interference between the two processes, and ensures the independence and effectiveness of the heat storage and heat release processes.

[0032] Furthermore, this system utilizes electric heating for heat storage, which can absorb the curtailment of new energy sources such as wind and solar power, improve energy cycle efficiency, increase the heat storage temperature of the heat storage medium, and enrich the application scenarios of the heat storage system.

[0033] Furthermore, the peak-shaving system coupled with flue gas from the coal-fired power plant and a single-tank solid thermal storage system, through a unique coupling method, not only improves the peak-shaving capacity of the coal-fired power plant, but also achieves efficient energy utilization, providing a more economical and feasible solution for the flexible transformation of thermal power plants. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a coal-fired power plant flue gas coupled with a single-tank solid thermal storage peak-shaving system according to an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of another coal-fired power plant flue gas coupled with a single-tank solid thermal storage peak-shaving system according to an embodiment of this application. Detailed Implementation

[0036] In the following description, numerous technical details are presented to facilitate the reader's understanding of this application. However, those skilled in the art will understand that the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0037] First, it should be noted that, unless otherwise defined, the technical terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this utility application pertains. The terms "top," "bottom," and other terms indicating orientation used in the embodiments of the application are only used to describe the exemplary relative positional relationships shown in the figures for ease of understanding and are not intended to limit the scope of protection of this application.

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0039] The embodiments of this application relate to a peak-shaving system that couples flue gas from a coal-fired power plant with a single-tank solid thermal storage system. Figure 1 and Figure 2 This is a schematic diagram of the structure of the peak-shaving system that couples flue gas and single-tank solid thermal storage in the coal-fired power plant.

[0040] Specifically, such as Figure 1 and Figure 2 As shown, the peak-shaving system of the coal-fired power plant flue gas coupled with single-tank solid thermal storage includes: a solid thermal accumulator 1, an electric heater 2, a heat exchanger 3, a fan 4, and a power supply 5, which are connected and fluidly communicated through a pipeline 6.

[0041] The solid heat accumulator 1 is filled with a solid heat storage medium for storing thermal energy.

[0042] The electric heater 2 is used to heat the heat transfer medium in heat storage mode.

[0043] The heat exchanger 3 is used to extract heat from the heat transfer medium in heat release mode and transfer the heat to the working fluid that needs to be heated.

[0044] In this embodiment, preferably, the working fluid to be heated is water, and the heat exchanger 3 is used to heat the water into steam.

[0045] The fan 4 is used to provide power for fluid circulation within the system in heat storage mode.

[0046] The power supply 5 is used to supply power to the electric heater 2 in heat storage mode.

[0047] In this embodiment, preferably, the power source is the surplus electrical energy generated by coal-fired power plants and new energy generator sets during peak shaving.

[0048] The bottom inlet of the solid heat accumulator 1 is connected to the flue gas outlet 8 of the coal-fired power plant through a first shut-off valve 71. The bottom outlet of the solid heat accumulator 1 is connected to the inlet of the fan 4 through a second shut-off valve 72. The outlet of the fan 4 is connected to the inlet of the electric heater 2. The outlet of the electric heater 2 is connected to the top port of the solid heat accumulator 1 through a third shut-off valve 73. The top port of the solid heat accumulator 1 is connected to the inlet of the heat exchanger 3 through a fourth shut-off valve 74.

[0049] like Figure 1 and Figure 2 As shown, in the peak-shaving system of flue gas and single-tank solid thermal storage coupled in this coal-fired power plant, the use of single-tank solid thermal storage to replace the traditional double-tank molten salt thermal storage greatly simplifies the overall system structure, reduces the number of equipment and the floor space required, and thus significantly reduces investment costs.

[0050] In this embodiment, preferably, the solid heat accumulator is provided with flow dividers at the top and bottom, with a solid heat storage medium in the middle. The solid heat storage medium includes concrete, rock, and / or metal spheres, etc.

[0051] Therefore, the peak-shaving system of the coal-fired power plant flue gas coupled with single-tank solid thermal storage includes: a thermal storage circuit and a thermal release circuit.

[0052] The heat storage circuit includes: a first shut-off valve 71, a solid heat accumulator 1, a second shut-off valve 72, a fan 4, an electric heater 2, a third shut-off valve 73, and a power supply 5.

[0053] The heat release circuit includes: a first shut-off valve 71, a solid heat accumulator 1, a fourth shut-off valve 74, and a heat exchanger 3.

[0054] During heat storage, the bottom of the solid heat accumulator 1 is connected to the fan 4, the fan 4 is connected to the electric heater 2, and the electric heater 2 is connected to the top of the solid heat accumulator 1. The solid heat accumulator 1, the fan 4, and the electric heater 2 are connected to form a heat storage circuit.

[0055] During heat release, the flue gas pipe leading from the flue gas outlet 8 of the coal-fired power plant is connected to the bottom of the solid heat accumulator 1, and the top of the solid heat accumulator 1 is connected to the heat exchanger 3. The solid heat accumulator 1 and the heat exchanger 3 are connected to form a heat release circuit.

[0056] In the heat storage circuit, shut-off valves are installed at the top and bottom of the solid heat storage unit 1, respectively. In the heat release circuit, shut-off valves are installed at the top and bottom of the solid heat storage unit 1, respectively.

[0057] The working modes of the coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage include: thermal storage mode and thermal release mode.

[0058] In the heat storage mode, the fourth shut-off valve 74 of the heat release circuit is closed; in the heat release mode, the second shut-off valve 72 and the third shut-off valve 73 of the heat storage circuit are closed, which can prevent heat from flowing back between the heat storage circuit and the heat release circuit, avoid heat loss and mutual interference between the two processes, and ensure the independence and effectiveness of the heat storage and heat release processes.

[0059] Furthermore, in the heat storage mode, the heat transfer medium is air and / or flue gas discharged from the flue gas outlet 8 of the coal-fired power plant; in the heat release mode, the heat transfer medium is flue gas discharged from the flue gas outlet 8 of the coal-fired power plant.

[0060] In this coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage, gas is used as the heat transfer medium, eliminating the need for facilities such as electric heat tracing and reducing operating costs.

[0061] Furthermore, by using the flue gas from the coal-fired power plant itself as a heat transfer medium, in the heat release mode, the pressure and flow rate of the flue gas discharged from the coal-fired power plant are cleverly utilized, eliminating the need for additional fans to drive heat transfer and further reducing operating costs. In the heat storage mode, the flue gas discharged from the coal-fired power plant, which has a certain temperature, can further utilize its own heat compared to the low-temperature air, which is more conducive to energy saving.

[0062] In the heat storage mode described above: First, low-temperature air and / or flue gas discharged from the flue gas outlet 8 of the coal-fired power plant are transported to the electric heater 2 via the fan 4. Simultaneously, excess electrical energy generated during peak shaving by the coal-fired power plant and new energy generator units (…) Figure 1 and Figure 2 (Using a coal-fired power plant as an example) The air and / or flue gas is fed into electric heater 2 to heat the air and / or flue gas. The heated air and / or flue gas then flows into solid heat accumulator 1. In solid heat accumulator 1, the hot air and / or flue gas exchange heat with the solid heat storage material. After heat exchange, the temperature of the air and / or flue gas decreases and flows out from the bottom outlet of solid heat accumulator 1; while the solid heat storage material absorbs heat and its temperature rises. This cycle continues until the entire heat storage process is completed.

[0063] In the heat release mode, the heat release process is as follows: First, low-temperature flue gas with a certain pressure and flow rate, discharged from the flue gas outlet 8 of the coal-fired power plant, is introduced into the bottom inlet of the solid heat accumulator 1. Then, in the solid heat accumulator 1, the low-temperature flue gas exchanges heat with the solid heat storage material. After heat exchange, the temperature of the low-temperature flue gas increases and it is discharged from the top port of the solid heat accumulator 1; while the temperature of the solid heat storage material decreases due to the release of heat. This cycle continues until the entire heat release process is completed.

[0064] This coal-fired power plant flue gas coupled with a single-tank solid thermal storage peak-shaving system ingeniously utilizes the power plant's own flue gas as the heat transfer medium for heat release operations. Low-temperature flue gas with a certain pressure and flow rate, discharged from the power plant's flue gas outlet, is directly introduced into the solid thermal accumulator for heat exchange. Inside the accumulator, the low-temperature flue gas comes into full contact with the solid thermal storage material, absorbing the heat released by the material and increasing its own temperature to become high-temperature flue gas. Subsequently, the high-temperature flue gas is introduced into the heat exchanger for further heat release, transferring the heat to the working fluid requiring heating, such as water or steam.

[0065] In this embodiment, preferably, the coal-fired power plant flue gas and single-tank solid heat storage coupled peak-shaving system may further include: a mixing shut-off valve 75 connected between the outlet of the heat exchanger 3 and the flue gas outlet 8. The mixing shut-off valve 75 is used to open when the inlet temperature of the cold side medium of the heat exchanger 3 is higher than a preset threshold, so as to mix the high-temperature flue gas with the low-temperature flue gas before it enters the solid heat storage tank 1.

[0066] In other words, when the inlet temperature of the medium on the cold side of the heat exchanger is high, the mixing shut-off valve 75, which is installed on the bypass of the outlet of the heat exchanger 3, can be opened to mix the high-temperature flue gas and the low-temperature flue gas into intermediate-temperature flue gas before entering the solid heat accumulator 1.

[0067] This coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage fully utilizes the pressure and velocity of the flue gas discharged from the flue gas outlet of the coal-fired power plant, eliminating the need for additional fans to drive heat transfer and reducing operating costs. This unique coupling method not only improves the peak-shaving capacity of the coal-fired power plant but also achieves efficient energy utilization, providing a more economical and feasible solution for the flexible retrofitting of thermal power plants.

[0068] To better understand the technical solution of this application, two specific embodiments are described below. The details listed in these embodiments are mainly for ease of understanding and are not intended to limit the scope of protection of this application.

[0069] Example 1:

[0070] like Figure 1 As shown, the main features of this embodiment 1 are described below:

[0071] (1) Produce steam with a flow rate of 65t / h, a steam pressure of 1.3MPa, a steam temperature of 260℃, and a feed water temperature of 120℃.

[0072] (2) The heat storage medium is rock, the heat storage temperature is 160-600℃, the net heat storage capacity is 88.5MWh (usually ≤100MWh), and the rock quantity is 2093 tons. The porosity is 0.45, the diameter of the solid heat storage device is 15m, and the height of the heat storage section is designed to be 7.7m.

[0073] (3) The temperature at the flue gas outlet of the coal-fired power plant is 160℃ (this scheme requires ≥130℃).

[0074] Example 2:

[0075] like Figure 2 As shown, the main features of this embodiment 2 are described below:

[0076] (1) Produce steam with a flow rate of 65t / h, a steam pressure of 1.3MPa, a steam temperature of 260℃, and a feed water temperature of 191.6℃.

[0077] (2) The heat storage medium is rock, the heat storage temperature is 200-600℃, the net heat storage capacity is 77.3MWh, and the rock quantity is 2090 tons. The porosity is 0.45, the diameter of the solid heat accumulator is 15m, and the height of the heat storage section is designed to be 7.7m.

[0078] (3) The temperature at the flue gas outlet of the coal-fired power plant is 160℃ (≥130℃ is required under this scheme). The 220℃ high-temperature flue gas passes through the outlet bypass of heat exchanger 3 and the mixing shut-off valve 75, and then mixes with the 160℃ low-temperature flue gas to form 200℃ flue gas, which then enters the solid heat accumulator.

[0079] In summary, the embodiments of this application propose a peak-shaving system that couples flue gas from a coal-fired power plant with single-tank solid thermal storage, providing a more economical and feasible solution for the flexible retrofitting of thermal power plants, with broad market application prospects and significant social benefits.

[0080] Compared with the prior art, the superior technical effects of the technical solution of this application mainly include:

[0081] (1) This system abandons the traditional dual-tank molten salt thermal storage mode and adopts a single-tank solid thermal storage design. This greatly simplifies the overall system structure, reduces the number of equipment and floor space, and thus significantly reduces investment costs. Traditional dual-tank molten salt thermal storage systems require two large tanks and complex piping connections and supporting equipment to store high-temperature molten salt and low-temperature molten salt respectively, while the single-tank solid thermal storage system only requires one thermal storage tank. Through special solid thermal storage materials and reasonable internal structure design, it can achieve both thermal storage and thermal release functions, effectively reducing equipment procurement, installation and maintenance costs.

[0082] (2) This system fully utilizes the pressure and velocity of the flue gas discharged from the flue gas outlet of a coal-fired power plant, eliminating the need for additional fans to drive heat transfer. In traditional solid thermal storage systems, high-power fans are typically required to force air or flue gas flow in order to achieve effective heat transfer. This not only increases the investment cost of the equipment but also consumes a large amount of electrical energy, leading to increased operating costs. However, this system avoids the power consumption of fans by rationally utilizing the natural flow characteristics of flue gas, significantly reducing energy consumption in the solid thermal storage process and further reducing operating costs.

[0083] (3) This system uses electric heating for heat storage, which can absorb the curtailment of new energy sources such as wind and solar power, improve energy cycle efficiency, and also increase the heat storage temperature of the heat storage medium, thus enriching the application scenarios of the heat storage system.

[0084] It should be noted that the components or devices mentioned in the embodiments of this application are all logical modules. Physically, a logical module can be a physical module, a part of a physical module, or a combination of multiple physical modules. The physical implementation of these logical modules themselves is not the most important factor; rather, the combination of functions implemented by these logical modules is the key to solving the technical problem proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described system embodiments have not introduced components or devices that are not closely related to solving the technical problem proposed in this application. This does not mean that other components or devices do not exist in the above embodiments.

[0085] It should be noted that in the claims and specification of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.

Claims

1. A peak-shaving system coupling flue gas from a coal-fired power plant with a single-tank solid thermal storage system, characterized in that, include: Solid accumulators, electric heaters, heat exchangers, fans, and power supplies are connected and fluidly communicated through pipes. The solid heat accumulator is filled with a solid heat storage medium for storing thermal energy. The electric heater is used to heat the heat transfer medium in heat storage mode; The heat exchanger is used to extract heat from the heat transfer medium in heat release mode and transfer the heat to the working fluid that needs to be heated. The fan is used to provide power for fluid circulation within the system in heat storage mode; The power supply is used to supply power to the electric heater in heat storage mode; The bottom inlet of the solid heat accumulator is connected to the flue gas outlet of the coal-fired power plant through a first shut-off valve. The bottom outlet of the solid heat accumulator is connected to the inlet of the blower through a second shut-off valve. The outlet of the blower is connected to the inlet of the electric heater. The outlet of the electric heater is connected to the top port of the solid heat accumulator through a third shut-off valve. The top port of the solid heat accumulator is connected to the inlet of the heat exchanger through a fourth shut-off valve.

2. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 1, characterized in that, The coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage includes: a thermal storage circuit and a heat release circuit; The heat storage circuit includes: a first shut-off valve, a solid heat accumulator, a second shut-off valve, a fan, an electric heater, a third shut-off valve, and a power supply; The heat release circuit includes: a first shut-off valve, a solid heat accumulator, a fourth shut-off valve, and a heat exchanger.

3. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 2, characterized in that, In the heat storage mode, the fourth shut-off valve of the heat release circuit is closed; in the heat release mode, the second and third shut-off valves of the heat storage circuit are closed.

4. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 1, characterized in that, In the heat storage mode, the heat transfer medium is air and / or flue gas discharged from the flue gas outlet of a coal-fired power plant; in the heat release mode, the heat transfer medium is flue gas discharged from the flue gas outlet of a coal-fired power plant.

5. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 1, characterized in that, The solid heat accumulator is equipped with flow dividers at the top and bottom, and the solid heat storage medium is in the middle.

6. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 5, characterized in that, The solid heat storage medium includes: concrete, rock and / or metal spheres.

7. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 1, characterized in that, Also includes: A mixing shut-off valve connected between the outlet of the heat exchanger and the flue gas outlet.

8. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 7, characterized in that, The mixing shut-off valve is used to open when the inlet temperature of the cold side medium of the heat exchanger is higher than a preset threshold, so as to mix the high-temperature flue gas with the low-temperature flue gas before it enters the solid heat accumulator.

9. The coal-fired power plant flue gas and single-tank solid thermal storage coupled peak-shaving system according to claim 1, characterized in that, The working medium that needs to be heated is water, and the heat exchanger is used to heat the water into steam.

10. The coal-fired power plant flue gas coupled peak-shaving system with single-tank solid thermal storage according to any one of claims 1-9, characterized in that, The power source is the surplus electrical energy generated by coal-fired power plants and new energy generator units during peak shaving.

Images