A molten salt energy storage system integrating storage and heat exchange and its working method

Abstract

An integrated molten salt energy storage system for heat storage and heat exchange and its working method disclosed by the present invention belong to the technical field of molten salt energy storage. An integrated molten salt energy storage device is internally provided with a heat charging coil and a heat releasing coil, and is filled with molten salt; both ends of the heat charging coil are connected to a steam / water inlet and a steam outlet, and are connected to a steam inlet; both ends of the heat releasing coil are connected to a high-temperature steam inlet and a low-parameter steam / condensate outlet; one molten salt outlet is connected to one molten salt inlet through a molten salt electric heater, and the other molten salt outlet is connected to the molten salt atomizing nozzles of each molten salt hydraulic tank through a molten salt input pump and a liquid seal device, and the other molten salt inlet is connected to a low-temperature molten salt outlet through a molten salt output pump; the high-parameter steam outlets are all connected to a high-temperature and high-pressure desalination device. The system of the present invention is reasonably designed, operates stably and efficiently, and has a high degree of integration, can make full use of molten salt energy storage, realize the storage of electric energy / high-parameter heat energy, release high-parameter heat energy, and improve the flexibility of thermal power units.

Description

Technical Field

[0001] The invention belongs to the technical field of molten salt energy storage, and particularly relates to an integrated energy storage and heat exchange molten salt energy storage system and a working method thereof. Background Art

[0002] Wind power and photovoltaic power have strong randomness, intermittency, uncontrollability and reverse peak shaving characteristics, which require existing thermal power units to have strong flexibility and the ability to operate at wide load ranges. Currently, the existing thermal power units have poor flexibility. The main reason is the strong coupling relationship between the boiler and the steam turbine. When wide-load operation is required, the steam turbine has good load regulation ability, but the boiler is limited by the minimum stable combustion load and cannot further reduce the load rate, restricting the peak shaving ability of the unit. To improve the flexibility and deep peak shaving ability of thermal power units, the molten salt energy storage system widely used in solar thermal power generation systems can be introduced into thermal power units to improve the peak shaving ability of thermal power units.

[0003] Dual-tank thermal energy storage with cold and hot tanks is the most common and relatively mature molten salt thermal energy storage form currently, and is widely used in solar thermal power plants. The entire operating system includes two tanks, a cold tank and a hot tank. The low-temperature heat exchange fluid is heated by a molten salt heat exchanger and then enters the hot tank for storage. When needed, heat is released through the heat exchanger. At this time, the low-temperature heat exchange fluid enters the cold tank for storage. The dual-tank thermal energy storage mode requires both tanks to be able to store all the fluids in the system, which results in some tank space not being utilized, increasing the investment cost and the floor area, and making it inconvenient to arrange. Summary of the Invention

[0004] To solve the above problems, the purpose of the present invention is to provide an integrated energy storage and heat exchange molten salt energy storage system and a working method thereof. The system is reasonably designed, operates stably and efficiently, has a high degree of integration, can make full use of molten salt energy storage, realizes the storage of electric energy / high-parameter thermal energy and the release of high-parameter thermal energy, and improves the flexibility of thermal power units.

[0005] The present invention is realized through the following technical solutions:

[0006] The present invention discloses an integrated energy storage and heat exchange molten salt energy storage system, including a molten salt electric heater, an integrated molten salt energy storage device, a molten salt input pump, a liquid seal device, a multi-stage molten salt hydraulic tank, a high-temperature and high-pressure desalting device, and a molten salt output pump;

[0007] The multi-stage molten salt hydraulic tank includes a plurality of molten salt hydraulic tanks connected in parallel. The top of the molten salt hydraulic tank is provided with a molten salt atomizing nozzle, a steam inlet and a high-parameter steam outlet, and the bottom is provided with a low-temperature molten salt outlet;

[0008] The integrated molten salt energy storage device is respectively provided with a high-temperature steam inlet, a steam / water inlet, a low-parameter steam / condensate outlet, a steam outlet, two molten salt inlets and two molten salt outlets; inside the integrated molten salt energy storage device, there are a heat charging coil and a heat discharging coil, and molten salt is filled; the inlet of the heat charging coil is connected to the steam / water inlet, the outlet is connected to the steam outlet, and is connected to the steam inlet; the inlet of the heat discharging coil is connected to the high-temperature steam inlet, and the outlet is connected to the low-parameter steam / condensate outlet; one of the molten salt outlets is connected to one of the molten salt inlets through a molten salt electric heater, and the other molten salt outlet is sequentially connected to the molten salt atomizing nozzles of each molten salt hydraulic tank through a molten salt input pump and a liquid seal device respectively, and the other molten salt inlet is connected to the low-temperature molten salt outlets of each molten salt hydraulic tank through a molten salt output pump respectively; the high-parameter steam outlets of each molten salt hydraulic tank are all connected to a high-temperature and high-pressure desalination device.

[0009] Preferably, the liquid seal device is a U-shaped liquid seal device.

[0010] Preferably, the high-temperature steam inlet and the steam outlet are arranged at the upper part of the integrated molten salt energy storage device, and the steam / water inlet and the low-parameter steam / condensate outlet are arranged at the lower part of the integrated molten salt energy storage device.

[0011] Preferably, the outer wall of the integrated molten salt energy storage device is provided with an anti-corrosion layer.

[0012] Preferably, a pressure gauge is provided on the pipeline connected to the high-parameter steam outlet of each molten salt hydraulic tank.

[0013] Preferably, the number of stages of the multi-stage molten salt hydraulic tank is 2 - 4.

[0014] Preferably, a molten salt inlet valve is provided on the pipeline connected to the molten salt atomizing nozzle, a steam inlet valve is provided on the pipeline connected to the steam inlet, a high-parameter steam outlet valve is provided on the pipeline connected to the high-parameter steam outlet, and a low-temperature molten salt outlet valve is provided on the pipeline connected to the molten salt outlet.

[0015] Preferably, the inner wall of the integrated molten salt energy storage device, the inner wall of the molten salt hydraulic tank, the outer wall of the heat charging coil and the outer wall of the heat discharging coil are all provided with anti-wear layers.

[0016] Preferably, the number of molten salt atomizing nozzles is multiple, the steam inlet and the high-parameter steam outlet are arranged side by side in the middle of the top of the molten salt hydraulic tank, and multiple molten salt atomizing nozzles are evenly distributed around the steam inlet and the high-parameter steam outlet.

[0017] The present invention discloses a working method of the above heat storage and heat exchange integrated molten salt energy storage system, including:

[0018] Use the peak shaving electricity to drive the molten salt electric heater to heat the molten salt in the integrated molten salt energy storage device, realizing electric heat storage; or extract the high-parameter steam of the thermal power unit and send it into the integrated molten salt energy storage device through the high-temperature steam inlet, and heat the molten salt through the heat release coil pipe to realize steam heat storage. The low-parameter steam / condensate after heat release is discharged from the low-parameter steam / condensate outlet;

[0019] When the thermal power plant needs to increase its output, feed water / superheated steam / reheat steam is sent into the heat charging coil pipe through the steam / feed water inlet. The high-temperature molten salt in the integrated molten salt energy storage device heats the steam / feed water into high-temperature steam through non-contact heat exchange, increasing the temperature;

[0020] The high-temperature steam fills the molten salt hydraulic tank through the steam outlet and the steam inlet. The high-temperature molten salt in the integrated molten salt energy storage device enters the molten salt hydraulic tank through the molten salt input pump and the molten salt atomizing nozzle. The liquid seal device prevents the steam from flowing back, continuously compresses and heats the high-temperature steam in the molten salt hydraulic tank, increasing the temperature and pressure of the high-temperature steam; when the pressure reaches the preset value, open the high-parameter steam outlet to discharge the high-parameter steam, and enter the high-temperature and high-pressure desalination device for desalination treatment; during the discharge process of the high-parameter steam, the molten salt hydraulic tank is continuously filled with molten salt; close the molten salt atomizing nozzle and the high-parameter steam outlet, and the molten salt returns to the integrated molten salt energy storage device through the molten salt output pump; complete a compression process;

[0021] A number of molten salt hydraulic tanks connected in parallel in the multi-stage molten salt hydraulic tank alternately cycle to complete the above compression process, and the system continuously discharges high-parameter steam.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] A molten salt energy storage system integrating storage and heat exchange can not only store electrical energy but also store thermal energy, with wide applicability. During the energy release process, the molten salt hydraulic tank can increase the temperature and pressure of the steam, improving the energy storage efficiency of the entire energy storage system. Most existing molten salt energy storage systems use a design with a cold tank + hot tank double-tank and an external heat exchanger. The integrated molten salt energy storage device of the present invention integrates the molten salt heat exchanger and the molten salt storage tank into the same tank body, and there is no need for electric tracing to prevent the molten salt from solidifying. If the molten salt solidifies, it can be restored by steam heating. It has a small floor area, is convenient for flexible layout, and has a lower construction cost. The molten salt inlet of the molten salt hydraulic tank is arranged to spray from top to bottom, and the molten salt atomizing nozzle atomizes it in a mechanical atomizing manner, which can increase the contact area between the molten salt and the steam, improve the heat exchange effect, and thus increase the steam temperature at the outlet of the molten salt hydraulic tank. Since the steam and the molten salt in the molten salt hydraulic tank are in contact heat exchange, a high-temperature and high-pressure desalting device is arranged on the high-parameter molten salt outlet pipeline to prevent the compressed steam from carrying molten salt particles into the steam turbine and affecting the service life of the steam turbine and the operating safety of the unit. In addition, through the layout of the integrated molten salt energy storage device + molten salt hydraulic device, when the thermal power unit raises or lowers the load, it can reduce the load by electrically heating / steam heating the molten salt without waiting for the load response on the boiler side, and can also increase the load by improving the quality of the steam through the integrated molten salt energy storage device + molten salt hydraulic device, thereby improving the variable load response rate of the thermal power unit. The molten salt hydraulic device of the present invention can utilize the molten salt stored in the integrated molten salt energy storage device. Only a small number of molten salt hydraulic tanks and two molten salt pumps need to be arranged to further increase the temperature and pressure of the steam output by the integrated molten salt energy storage device, thereby improving the load increase capacity of the unit.

[0024] Further, the liquid seal device adopts a U-shaped liquid seal device, which has a simple structure and can effectively prevent the steam in the molten salt hydraulic tank from flowing back through the molten salt atomizing nozzle 7 during the compression process, maintaining the pressure in the system and improving the performance and safety of the entire system.

[0025] Further, the outer wall of the integrated molten salt energy storage device is provided with a heat insulation layer, which can ensure the fluidity of the molten salt and reduce the heat dissipation of the molten salt in the tank, improving the energy storage effect.

[0026] Further, a pressure gauge is provided on the pipeline connected to the high-parameter steam outlet of each molten salt hydraulic tank, which can monitor the steam pressure in the molten salt hydraulic tank in real time, and then control the opening and closing of the corresponding valve.

[0027] Further, the number of stages of the multi-stage molten salt hydraulic tank is 2 to 4. The 2 to 4 molten salt hydraulic tanks can be connected in parallel to continuously discharge high-parameter steam.

[0028] Furthermore, the inner walls of the integrated molten salt energy storage device, the molten salt hydraulic tank, the outer walls of the heat charging coil and the heat releasing coil are all provided with anti-corrosion layers to extend the service life of the equipment in the system.

[0029] The working method of the integrated heat storage and heat exchange molten salt energy storage system disclosed by the present invention has high automation, simple operation and maintenance, can make full use of molten salt energy storage, realize the storage of electric energy / high-parameter heat energy and the release of high-parameter heat energy, and improve the flexibility of thermal power units. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the overall structure of the system of the present invention;

[0031] Figure 2 is a top view schematic diagram of the molten salt hydraulic tank.

[0032] In the figure: 1 - molten salt electric heater; 2 - integrated molten salt energy storage device; 3 - heat charging coil; 4 - heat releasing coil; 5 - molten salt input pump; 6 - liquid seal device; 7 - molten salt atomizing nozzle; 8 - steam inlet; 9 - high-parameter steam outlet; 10 - first-stage molten salt hydraulic tank; 11 - second-stage molten salt hydraulic tank; 12 - high-temperature and high-pressure desalting device; 13 - first low-temperature molten salt outlet valve; 14 - second low-temperature molten salt outlet valve; 15 - first steam inlet valve; 16 - second steam inlet valve; 17 - first molten salt inlet valve; 18 - second molten salt inlet valve; 19 - first high-parameter steam outlet valve; 20 - second high-parameter steam outlet valve; 21 - molten salt output pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following further describes the present invention in detail with reference to the drawings and embodiments. The content is an explanation of the present invention rather than a limitation:

[0034] As Figure 1 , the integrated heat storage and heat exchange molten salt energy storage system of the present invention includes a molten salt electric heater 1, an integrated molten salt energy storage device 2, a molten salt input pump 5, a liquid seal device 6, a multi-stage molten salt hydraulic tank, a high-temperature and high-pressure desalting device 12 and a molten salt output pump 21;

[0035] The multi-stage molten salt hydraulic tank includes a plurality of molten salt hydraulic tanks connected in parallel. The top of the molten salt hydraulic tank is provided with a molten salt atomizing nozzle 7, a steam inlet 8 and a high-parameter steam outlet 9, and the bottom is provided with a low-temperature molten salt outlet;

[0036] The integrated molten salt energy storage device 2 is respectively provided with a high-temperature steam inlet, a steam / water inlet, a low-parameter steam / condensate outlet, a steam outlet, two molten salt inlets and two molten salt outlets; inside the integrated molten salt energy storage device 2, there are a heat charging coil 3 and a heat discharging coil 4, and it is filled with molten salt; the inlet of the heat charging coil 3 is connected to the steam / water inlet, the outlet is connected to the steam outlet, and is connected to the steam inlet 8; the inlet of the heat discharging coil 4 is connected to the high-temperature steam inlet, and the outlet is connected to the low-parameter steam / condensate outlet; one of the molten salt outlets is connected to one of the molten salt inlets through the molten salt electric heater 1, and the other molten salt outlet is successively connected to the molten salt atomizing nozzles 7 of each molten salt hydraulic tank through the molten salt input pump 5 and the liquid seal device 6 respectively, and the other molten salt inlet is connected to the low-temperature molten salt outlets of each molten salt hydraulic tank through the molten salt output pump 21 respectively; the high-parameter steam outlets 9 of each molten salt hydraulic tank are all connected to the high-temperature and high-pressure desalination device 12.

[0037] In a preferred embodiment of the present invention, the liquid seal device 6 is a U-shaped liquid seal device.

[0038] In a preferred embodiment of the present invention, the high-temperature steam inlet and the steam outlet are arranged at the upper part of the integrated molten salt energy storage device 2, and the steam / water inlet and the low-parameter steam / condensate outlet are arranged at the lower part of the integrated molten salt energy storage device 2.

[0039] In a preferred embodiment of the present invention, the outer wall of the integrated molten salt energy storage device 2 is provided with a heat insulation layer.

[0040] In a preferred embodiment of the present invention, pressure gauges are arranged on the pipelines connected to the high-parameter steam outlets 9 of each molten salt hydraulic tank.

[0041] In a preferred embodiment of the present invention, the number of stages of the multi-stage molten salt hydraulic tank is 2 to 4.

[0042] In a preferred embodiment of the present invention, a molten salt inlet valve is arranged on the pipeline connected to the molten salt atomizing nozzle 7, a steam inlet valve is arranged on the pipeline connected to the steam inlet 8, a high-parameter steam outlet valve is arranged on the pipeline connected to the high-parameter steam outlet 9, and a low-temperature molten salt outlet valve is arranged on the pipeline connected to the molten salt outlet.

[0043] In a preferred embodiment of the present invention, anti-corrosion layers are arranged on the inner wall of the integrated molten salt energy storage device 2, the inner wall of the molten salt hydraulic tank, the outer wall of the heat charging coil 3 and the outer wall of the heat discharging coil 4.

[0044] In a preferred embodiment of the present invention, the number of molten salt atomizing nozzles 7 is multiple. The steam inlet 8 and the high-parameter steam outlet 9 are arranged side by side in the middle of the top of the molten salt hydraulic tank, and the multiple molten salt atomizing nozzles 7 are evenly distributed around the steam inlet 8 and the high-parameter steam outlet 9.

[0045] When the above-mentioned integrated molten salt energy storage system for heat storage and heat exchange works:

[0046] Use the peak shaving power to drive the molten salt electric heater 1 to heat the molten salt in the integrated molten salt energy storage device 2 to achieve electric heat storage; or extract the high-parameter steam of the thermal power unit and send it into the integrated molten salt energy storage device 2 from the high-temperature steam inlet, and heat the molten salt through the heat release coil 4 to achieve steam heat storage. The low-parameter steam / condensate after heat release is discharged from the low-parameter steam / condensate outlet;

[0047] When the thermal power plant needs to increase its output, send the steam after the work of the steam turbine or the superheated steam at the boiler outlet or the feed water into the heat charging coil 3 from the steam / feed water inlet. The high-temperature molten salt in the integrated molten salt energy storage device 2 heats the steam / feed water into high-temperature steam through non-contact heat exchange to increase the temperature;

[0048] The high-temperature steam fills the molten salt hydraulic tank from the steam outlet through the steam inlet 8. The high-temperature molten salt in the integrated molten salt energy storage device 2 enters the molten salt hydraulic tank through the molten salt atomizing nozzle 7 by the molten salt input pump 5. The liquid seal device 6 prevents the steam from flowing back, continuously compresses and heats the high-temperature steam in the molten salt hydraulic tank to increase the temperature and pressure of the high-temperature steam; when the pressure reaches the preset value, open the high-parameter steam outlet 9 to discharge the high-parameter steam and enter the high-temperature and high-pressure desalination device 12 for desalination treatment; during the discharge process of the high-parameter steam, the molten salt hydraulic tank is continuously filled with molten salt; close the molten salt atomizing nozzle 7 and the high-parameter steam outlet 9, and the molten salt returns to the integrated molten salt energy storage device 2 through the molten salt output pump 21; complete a compression process;

[0049] Several molten salt hydraulic tanks connected in parallel in the multi-stage molten salt hydraulic tank alternately cycle to complete the above compression process, and the system continuously discharges high-parameter steam.

[0050] The following uses a specific embodiment to further explain the present invention:

[0051] Such as Figure 1 , the multi-stage molten salt hydraulic tank in this embodiment includes two stages, namely the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11, which are connected in parallel, and the compression working medium is steam.

[0052] There are two molten salt outlets at the lower part of the modular molten salt thermal energy storage device 2 in the system, and two molten salt inlets at the upper part. One of the molten salt outlets is connected to the inlet of the molten salt electric heater, and one of the molten salt inlets is connected to the outlet of the molten salt electric heater 1; the other molten salt outlet is successively connected to the molten salt atomizing nozzles 7 of the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11 through the molten salt input pump 5, the liquid seal device 6, the first molten salt inlet valve 17, and the second molten salt inlet valve 18; the other molten salt inlet is respectively connected to the molten salt outlets at the bottoms of the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11 through the molten salt output pump 21, the first low-temperature molten salt outlet valve 13, and the second low-temperature molten salt outlet valve 14.

[0053] The heat charging coil 3 and the heat discharging coil 4 are respectively arranged inside the integrated molten salt energy storage device 2, and the molten salt is between the two coils and the shell of the modular molten salt energy storage 2 device; there are a high-temperature steam inlet and a steam outlet at the top of the integrated molten salt energy storage device 2, which are respectively connected to the inlet of the heat discharging coil 4 and the outlet of the heat charging coil 3; there are a low-parameter steam / condensate outlet and a low-temperature steam / water inlet at the bottom of the integrated molten salt energy storage device 2, which are respectively connected to the outlet of the heat discharging coil 4 and the inlet of the heat charging coil 3.

[0054] As Figure 2 , the structures of the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11 are the same, both are cylindrical structures, with a steam inlet 8, a high-parameter steam outlet 9, and several molten salt atomizing nozzles 7 at the top; among them, the steam inlet 8 and the high-parameter steam outlet 9 are arranged side by side in the middle of the top of the molten salt hydraulic tank, and several molten salt atomizing nozzles 7 are evenly distributed around the steam inlet 8 and the high-parameter steam outlet 9, and the molten salt atomizing nozzles 7 adopt the mechanical atomization method; there are low-temperature molten salt outlets at the bottoms of the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11, which are respectively connected to the low-temperature molten salt inlet at the top of the modular molten salt storage tank 2 through the first low-temperature molten salt outlet valve 13 and the second low-temperature molten salt outlet valve 14 via the molten salt output pump 21. The high-parameter steam outlets 9 at the tops of the first-stage molten salt hydraulic tank 10 and the second-stage molten salt hydraulic tank 11 are respectively connected to the high-temperature high-pressure desalination device 12 through the first high-parameter steam outlet valve 19 and the second high-parameter steam outlet valve 20 for desalination treatment.

[0055] The liquid seal device 6 is arranged on the high-temperature molten salt pipeline, and a liquid seal section is formed at the bottom of the liquid seal device 6 to prevent the steam in the molten salt hydraulic tank from flowing back to the integrated molten salt energy storage device 2 through the molten salt atomizing nozzles 7 during the compression process, thereby improving the performance and safety of the entire system.

[0056] When the above system is applied to the deep peak shaving of a thermal power plant, it includes the following steps:

[0057] Step 1, heat charging:

[0058] The surplus electric energy or high-parameter steam thermal energy is stored in the integrated molten salt energy storage device 2 by means of electric-molten salt heat and steam heat to molten salt heat. There are two charging methods. One is to drive the molten salt electric heater 1 with the peak-shaving power to heat the molten salt in the integrated molten salt energy storage device 2 to achieve electric heat storage; the other is to extract the high-parameter steam from the thermal power unit and send it into the integrated molten salt energy storage device 2 to heat the molten salt to achieve steam heat storage.

[0059] Step 2, heat release:

[0060] When the thermal power plant needs to increase its output, feed water / superheated steam at the outlet of the superheater / reheated steam at the outlet of the reheater is sent into the charging coil 3 from the bottom of the integrated molten salt energy storage device 2. The high-temperature molten salt in the integrated molten salt energy storage device 2 exchanges heat with the feed water / superheated steam / reheated steam in a non-contact manner to heat the feed water into high-temperature steam / increase the temperature of the reheated steam or superheated steam.

[0061] Step 3, further increase the temperature and pressure of the high-temperature steam by using the molten salt hydraulic tank:

[0062] (1) First, open the steam inlet valve at the top of the molten salt hydraulic tank, and the steam heated by the integrated molten salt energy storage device 2 enters the molten salt hydraulic tank until it is full;

[0063] (2) Close the molten salt outlet valve, high-parameter steam outlet valve and steam inlet valve, open the molten salt input pump 5 and the high-temperature molten salt inlet valve. The high-temperature molten salt continuously enters the molten salt hydraulic tank through the molten salt atomizing nozzle 7, continuously compresses the steam in the molten salt hydraulic tank, and is further heated by the high-temperature molten salt, thereby further increasing the temperature and pressure of the steam;

[0064] (3) When the pressure reaches a certain value, open the high-parameter steam outlet valve at the top to discharge the high-temperature and high-pressure steam. As the high-temperature and high-pressure working medium is continuously discharged, the molten salt hydraulic tank is continuously filled with molten salt;

[0065] (4) Close the molten salt inlet valve and high-parameter steam outlet valve at the top of the molten salt hydraulic tank, open the molten salt discharge valve at the bottom of the molten salt hydraulic tank and the steam inlet valve at the top. Under the action of the molten salt output pump 21, the molten salt quickly returns to the integrated molten salt energy storage device 2. At the same time, steam is continuously injected into the molten salt hydraulic tank through the steam inlet at the top until it is full, completing a compression process.

[0066] Two-stage molten salt hydraulic tanks are connected in parallel. The first-stage molten salt hydraulic tank 10 sequentially executes the above steps (1), (2), (3). When the first-stage molten salt hydraulic tank 10 executes step (3), the second-stage molten salt hydraulic tank 11 sequentially executes steps (4), (1), (2). The two-stage molten salt hydraulic tanks operate alternately and cyclically in this way, so that the steam sent into the molten salt hydraulic tank is heated, pressurized and can be continuously discharged.

[0067] Step 4: The high-parameter steam after molten salt hydro-upgrading removes the molten salt particles carried in the steam through the high-temperature and high-pressure desalination device 12, and then is sent into the steam turbine to do work, and then is converted into electric energy and released, thereby improving the work capacity of the unit.

[0068] As mentioned above, it is only a part of the embodiments of the present invention. Although some terms are used in the present invention, it does not exclude the possibility of using other terms. These terms are only used for the convenience of description and explanation of the essence of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention. The above is only described by way of examples to further illustrate the content of the present invention for easier understanding, but it does not mean that the embodiments of the present invention are limited thereto. Any technical extension or re-creation based on the present invention is protected by the present invention.

Claims

1. A molten salt energy storage system integrating heat storage and heat exchange, characterized in that, it includes a molten salt electric heater (1), an integrated molten salt energy storage device (2), a molten salt input pump (5), a liquid seal device (6), a multi-stage molten salt hydraulic tank, a high-temperature and high-pressure desalination device (12) and a molten salt output pump (21); The multi-stage molten salt hydraulic tank includes a number of molten salt hydraulic tanks connected in parallel. The top of the molten salt hydraulic tank is provided with a molten salt atomizing nozzle (7), a steam inlet (8) and a high-parameter steam outlet (9), and the bottom is provided with a low-temperature molten salt outlet; The integrated molten salt energy storage device (2) is respectively provided with a high-temperature steam inlet, a steam / water inlet, a low-parameter steam / condensate outlet, a steam outlet, two molten salt inlets and two molten salt outlets; inside the integrated molten salt energy storage device (2), there are a heat charging coil (3) and a heat discharging coil (4), and it is filled with molten salt; the inlet of the heat charging coil (3) is connected to the steam / water inlet, the outlet is connected to the steam outlet, and is connected to the steam inlet (8); the inlet of the heat discharging coil (4) is connected to the high-temperature steam inlet, and the outlet is connected to the low-parameter steam / condensate outlet; one of the molten salt outlets is connected to one of the molten salt inlets through the molten salt electric heater (1), and the other molten salt outlet is respectively connected to the molten salt atomizing nozzles (7) of each molten salt hydraulic tank through the molten salt input pump (5) and the liquid seal device (6) in sequence, and the other molten salt inlet is respectively connected to the low-temperature molten salt outlets of each molten salt hydraulic tank through the molten salt output pump (21); the high-parameter steam outlets (9) of each molten salt hydraulic tank are all connected to the high-temperature and high-pressure desalination device (12).

2. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, the liquid seal device (6) is a U-shaped liquid seal device.

3. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, the high-temperature steam inlet and the steam outlet are arranged on the upper part of the integrated molten salt energy storage device (2), and the steam / water inlet and the low-parameter steam / condensate outlet are arranged on the lower part of the integrated molten salt energy storage device (2).

4. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, the outer wall of the integrated molten salt energy storage device (2) is provided with an anti-corrosion layer.

5. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, pressure gauges are arranged on the pipelines connected to the high-parameter steam outlets (9) of each molten salt hydraulic tank.

6. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, the number of stages of the multi-stage molten salt hydraulic tank is 2 - 4.

7. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, a molten salt inlet valve is arranged on the pipeline connected to the molten salt atomizing nozzle (7), a steam inlet valve is arranged on the pipeline connected to the steam inlet (8), a high-parameter steam outlet valve is arranged on the pipeline connected to the high-parameter steam outlet (9), and a low-temperature molten salt outlet valve is arranged on the pipeline connected to the molten salt outlet.

8. The molten salt energy storage system integrating heat storage and heat exchange according to claim 1, characterized in that, The inner wall of the integrated molten salt energy storage device (2), the inner wall of the molten salt hydraulic tank, the outer wall of the heat charging coil (3), and the outer wall of the heat discharging coil (4) are all provided with anti-wear layers.

9. The heat storage and heat exchange integrated molten salt energy storage system according to claim 1, characterized in that the number of molten salt atomizing nozzles (7) is multiple, the steam inlet (8) and the high-parameter steam outlet (9) are arranged side by side in the middle of the top of the molten salt hydraulic tank, and multiple molten salt atomizing nozzles (7) are evenly distributed around the steam inlet (8) and the high-parameter steam outlet (9).

10. The working method of the heat storage and heat exchange integrated molten salt energy storage system according to any one of claims 1 to 9, characterized in that it includes: using peak shaving power to drive the molten salt electric heater (1) to heat the molten salt in the integrated molten salt energy storage device (2) to realize electric heat storage; or extracting high-parameter steam from a thermal power unit and feeding it into the integrated molten salt energy storage device (2) through the high-temperature steam inlet, heating the molten salt through the heat discharging coil (4) to realize steam heat storage, and discharging the low-parameter steam / condensate after heat release from the low-parameter steam / condensate outlet; when the thermal power plant needs to increase its output, feeding water / superheated steam / reheated steam into the heat charging coil (3) through the steam / water inlet, and the high-temperature molten salt in the integrated molten salt energy storage device (2) heats the steam / water into high-temperature steam through non-contact heat exchange to increase the temperature; the high-temperature steam fills the molten salt hydraulic tank through the steam outlet and the steam inlet (8), the high-temperature molten salt in the integrated molten salt energy storage device (2) enters the molten salt hydraulic tank through the molten salt atomizing nozzle (7) by the molten salt input pump (5), and the liquid seal device (6) prevents steam from flowing back, continuously compressing and heating the high-temperature steam in the molten salt hydraulic tank to increase the temperature and pressure of the high-temperature steam; when the pressure reaches the preset value, open the high-parameter steam outlet (9) to discharge the high-parameter steam and enter the high-temperature and high-pressure desalination device (12) for desalination treatment; during the discharge process of the high-parameter steam, the molten salt hydraulic tank is continuously filled with molten salt; close the molten salt atomizing nozzle (7) and the high-parameter steam outlet (9), and the molten salt returns to the integrated molten salt energy storage device (2) through the molten salt output pump (21); complete a compression process; several molten salt hydraulic tanks connected in parallel in the multi-stage molten salt hydraulic tank alternately cycle to complete the above compression process, and the system continuously discharges high-parameter steam.

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