An efficient heat exchange system and heat exchange process for an energy storage system

Abstract

The present application relates to an efficient heat exchange system and a heat exchange process for an energy storage system. The system includes an energy storage tank filled with molten salt inside, a heat exchange coil is arranged in the energy storage tank, and a heat storage mechanism is also arranged in the energy storage tank. The high-temperature steam outlet of the heat exchange coil is connected with a plurality of first-order steam pipes, one first-order steam pipe is connected with a pressurizing tank, a second-order steam pipe is connected to the pressurizing tank, and a second-order pressure control valve is arranged on the second-order steam pipe; a heat transfer plate is hermetically and slidably arranged in the pressurizing tank, and the heat transfer plate divides the inner cavity of the pressurizing tank into a pressure-receiving area and a pressurizing area, and the first-order steam pipe and the second-order steam pipe are both communicated in the pressure-receiving area; the pressurizing tank is connected with a pressure regulating pipe with one end communicated with the pressurizing area and the other end communicated with the energy storage tank, and a pressurizing mechanism for conveying the molten salt therein to the pressurizing tank through the pressure regulating pipe is arranged on the energy storage tank. The present application separates the high-temperature molten salt from the high-temperature steam through the heat transfer plate, reduces the heat loss during the desalting process, and effectively ensures the thermal efficiency of the heat exchange system.

Description

Technical Field

[0001] This application relates to the technical field of energy storage systems, and particularly to an efficient heat exchange system and heat exchange process for an energy storage system. Background Art

[0002] Whether it is photo-thermal energy storage, electro-thermal energy storage or thermal-thermal energy storage, it is necessary to go through the preheating, evaporation, superheating and recuperation of the heat storage medium. The reason why the two processes of superheating and recuperation are essential here is that part of the energy of the storage medium after evaporation is used to maintain the operation of the entire heat storage system, and the other part is directly reheated, that is, superheated, for energy storage. Finally, whether it is the storage medium used for the operation of the heat storage system or the storage medium reheated again, they are all collected for energy storage and circulation. By integrating superheating and recuperation, the coupling and synchronization of superheating and recuperation are realized, which also saves the cost in the entire energy storage (heat exchange) process and reduces the technological process in the energy storage process of the heat exchanger.

[0003] For example, in the Chinese patent with the application number CN202310035024.X in the related art, a storage and heat exchange integrated molten salt energy storage system and its working method are proposed. Inside the device, there are heat charging coils and heat discharging coils, and molten salt is filled; both ends of the heat charging coil are connected to the steam / water inlet and the steam outlet, and are connected to the steam inlet; both ends of the heat discharging coil are connected to the high-temperature steam inlet and the 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 nozzle 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 the low-temperature molten salt outlet through a molten salt output pump; the high-parameter steam outlets are all connected to the high-temperature and high-pressure desalination device.

[0004] The above-mentioned related art has the following defects: In the process of pressurizing and reheating the high-temperature steam by atomizing and spraying the molten salt, although the reheating efficiency of the high-temperature molten salt on the high-temperature steam can be greatly enhanced, the requirements for the conveying pressure and temperature resistance of the molten salt input pump are extremely high. Moreover, once the temperature of the molten salt decreases and its fluidity weakens, it will greatly increase the load of the input pump, and it is difficult to maintain the stable and long-term operation of the heat exchange system; and when the atomized molten salt removes the salt in the superheated steam through the high-temperature and high-pressure desalination device, heat loss will inevitably occur, and the relatively low temperature of the processed salt will also affect the temperature of the superheated steam to a certain extent. Therefore, the heat exchange efficiency of the overall heat exchange system still needs to be improved. Summary of the Invention

[0005] In order to improve the problem that the heat exchange efficiency may be reduced and the system operation stability may be weakened when pressurizing and reheating the high-temperature steam by atomizing and spraying the molten salt, this application provides an efficient heat exchange system and heat exchange process for an energy storage system.

[0006] An efficient heat exchange system for an energy storage system provided by the first aspect of the present application adopts the following technical solutions:

[0007] An efficient heat exchange system for an energy storage system includes an energy storage tank filled with molten salt inside. A heat exchange coil is arranged in the energy storage tank. One end of the heat exchange coil is a low-temperature medium inlet and the other end is a high-temperature steam outlet. A heat storage mechanism for heating the molten salt in the energy storage tank is also arranged in the energy storage tank. The high-temperature steam outlet of the heat exchange coil is connected with a plurality of first-order steam pipes. One first-order steam pipe is connected with one pressurizing tank. A second-order steam pipe is connected to the pressurizing tank, and a second-order pressure control valve is arranged on the second-order steam pipe;

[0008] A heat transfer plate is hermetically and slidably arranged in the pressurizing tank. The heat transfer plate divides the inner cavity of the pressurizing tank into a pressure-receiving area and a pressurizing area. The first-order steam pipe and the second-order steam pipe are both communicated in the pressure-receiving area;

[0009] A pressure regulating pipe is connected to the pressurizing tank. One end of the pressure regulating pipe is communicated with the pressurizing area and the other end is communicated with the energy storage tank. A pressurizing mechanism for transporting the molten salt in the energy storage tank to the pressurizing tank through the pressure regulating pipe is arranged on the energy storage tank.

[0010] Furthermore, the end of the pressure regulating pipe communicated with the energy storage tank is located in the middle and lower part of the energy storage tank. The pressurizing mechanism includes an air pump communicated with an inert gas source and a charging pipe communicated with the output end of the air pump. The charging pipe extends into the energy storage tank.

[0011] Furthermore, the charging pipe extends to the bottom of the energy storage tank.

[0012] Furthermore, a plurality of flow equalizing pipes communicated with the charging pipe are arranged above the inner bottom wall of the energy storage tank.

[0013] Furthermore, an electromagnetic reversing one-way valve is arranged on the pressure regulating pipe. When high-temperature steam is continuously introduced into the pressure-receiving area through the first-order steam pipe, the electromagnetic reversing one-way valve controls the liquid flow in the pressure regulating pipe to only flow from the pressurizing tank to the energy storage tank;

[0014] When the introduction of high-temperature steam into the pressure-receiving area stops, the electromagnetic reversing one-way valve controls the liquid flow in the pressure regulating pipe to only flow from the energy storage tank to the pressurizing tank.

[0015] Furthermore, a plurality of through holes are formed through the heat transfer plate. Heat conducting rods are hermetically and slidably arranged in the through holes. Limiting pieces are fixedly connected to both ends of the heat conducting rods.

[0016] Further, a sealing sleeve made of polytetrafluoroethylene is fixed on the perforated hole wall of the heat transfer plate, and the heat conduction rod is slidably arranged in the sealing sleeve.

[0017] Further, a pressure relief pipe is connected to the upper part of the energy storage tank, and a pressure relief valve is arranged on the pressure relief pipe.

[0018] Further, a first-stage pressure control valve is connected to the first-stage steam pipe. Multiple pressurizing tanks are grouped into heat exchange groups with two pressurizing tanks in each group. If one of the two first-stage pressure control valves in the same heat exchange group is in the open state, the other is in the closed state.

[0019] The efficient heat exchange process for an energy storage system provided in the second aspect of the present application adopts the following technical solutions:

[0020] An efficient heat exchange process for an energy storage system, based on the above-mentioned efficient heat exchange system for an energy storage system, includes the following steps:

[0021] Utilize the peak shaving power or the high-temperature steam of the thermal power unit to heat the molten salt in the energy storage tank through the heat storage mechanism. The energy storage tank stores the high-temperature molten salt in a heat-insulated manner to complete heat storage;

[0022] When heat release is required, introduce a low-temperature medium into the low-temperature medium inlet of the heat exchange coil. The high-temperature molten salt in the energy storage tank heats the low-temperature medium in the heat exchange coil into high-temperature steam, which is discharged from the first-stage steam pipe;

[0023] The high-temperature steam is introduced into the corresponding pressurizing tank through one of the first-stage steam pipes. The volume of the pressurized area increases, and the heat transfer plate moves towards the pressurizing area to return the molten salt in the pressurizing area to the energy storage tank through the pressure regulating pipe; after the pressurized area is filled with high-temperature steam, the pressurizing mechanism transports the high-temperature molten salt in the energy storage tank to the pressurizing area. The heat transfer plate moves towards the pressurized area, and the high-temperature steam in the pressurized area is compressed and reheated to form high-parameter steam, which is discharged from the second-stage steam pipe; to complete one compression process;

[0024] Multiple parallel pressurizing tanks alternately complete the above compression process, so that high-parameter steam is continuously discharged from multiple second-stage steam pipes.

[0025] In summary, the beneficial technical effects of the present application are:

[0026] 1. When the heat exchange system needs to release heat, a low-temperature medium is introduced into the low-temperature medium inlet of the heat exchange coil. The high-temperature molten salt in the energy storage tank heats the low-temperature medium in the heat exchange coil into high-temperature steam, which is discharged from multiple first-order steam pipes. The high-temperature steam is introduced into the corresponding pressure tank through one of the first-order steam pipes, causing the heat transfer plate to move towards the pressurized area, so that the molten salt in the pressurized area is returned to the energy storage tank through the pressure regulating pipe. When the high-temperature steam in the pressurized area is full, the charging pipe fills the energy storage tank with inert gas to continuously transport the high-temperature molten salt in the energy storage tank to the pressurized area. The heat transfer plate moves towards the pressurized area, and the high-temperature molten salt in the pressurized area reheats the high-temperature steam in the pressurized area through the heat transfer plate. Thus, the high-temperature steam in the pressurized area is compressed and reheated to form high-parameter steam, which is discharged from the second-order steam pipe. At this time, a compression process is completed, the high-temperature steam can be reheated into high-parameter steam, and the circulation of the high-temperature molten salt between the pressure tank and the energy storage tank can be promoted, reducing heat energy loss and significantly improving the thermal efficiency of the heat exchange system;

[0027] 2. After introducing an appropriate amount of inert gas into the energy storage tank, the air pressure in the energy storage tank increases, and the high-temperature molten salt can be transported through the pressure regulating pipe to the pressurized area of the pressure tank where high-temperature steam is no longer being filled. At the same time, the molten salt in the pressurized area of another pressure tank in the same heat exchange group is also squeezed out and returned to the energy storage tank, which can also promote the increase of the internal pressure in the energy storage tank. In this way, the alternating circulation of the high-temperature molten salt in the energy storage tank between the two pressure tanks in the same heat exchange group can be realized, that is, the continuous supply of the high-temperature molten salt required for multiple heat exchange groups can be achieved. Moreover, only the inert gas needs to be filled into the charging pipe at the initial stage of system startup. After the two compression processes of each heat exchange group alternate and operate smoothly, there is no need to continuously supplement inert gas into the energy storage tank. Only when the internal pressure in the energy storage tank decreases due to the consumption of inert gas during system operation, the inert gas needs to be supplemented;

[0028] 3. The setting of the heat conduction rods on the heat transfer plate can further increase the heat transfer area between the high-temperature steam in the pressurized area and the high-temperature molten salt in the pressurized area, thereby improving the heat transfer efficiency of the high-temperature molten salt in the heating tank. And through the sliding setting of the heat conduction rods on the heat transfer plate, it can ensure as much as possible the discharge of the molten salt after heat exchange in the pressurized area and the compression of the high-temperature steam in the pressurized area to the required pressure. Description of the Drawings

[0029] Figure 1 is the overall structural schematic diagram of the embodiment of the present application

[0030] Figure 2 is Figure 1 the partial enlarged schematic diagram of part A in

[0031] Description of the Reference Numerals:

[0032] 1. Energy storage tank; 11. Heat storage mechanism;

[0033] 2. Heat exchange coil; 21. Low-temperature medium inlet; 22. High-temperature steam outlet;

[0034] 311. First-order steam pipe; 312. First-order pressure control valve; 321. Second-order steam pipe; 322. Second-order pressure control valve; 323. Pressure gauge;

[0035] 4. Pressurization tank; 41. Pressure-receiving area; 42. Pressurization area; 43. Pressure-regulating pipe; 44. Electromagnetic reversing check valve;

[0036] 5. Heat transfer plate; 51. Perforation; 52. Heat conduction rod; 53. Limiting piece; 54. Sealing sleeve; 55. Sealing ring;

[0037] 61. Air pump; 62. Inflation pipe; 63. Flow equalizing pipe;

[0038] 71. Pressure relief pipe; 72. Pressure relief valve. Specific implementation manner

[0039] The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0040] An embodiment of the present application discloses an efficient heat exchange system for an energy storage system. Referring to Figure 1 , it includes an energy storage tank 1 filled with molten salt inside. A heat exchange coil 2 is arranged in the energy storage tank 1. One end of the heat exchange coil 2 is a low-temperature medium inlet 21, and the other end is a high-temperature steam outlet 22. A heat storage mechanism 11 for heating the molten salt in the energy storage tank 1 is also arranged in the energy storage tank 1; among them, the heat storage mechanism 11 can be an electric heating device or a coil for high-temperature steam heat exchange, and can be selected and used according to the actual situation of the surplus energy.

[0041] The high-temperature steam outlet 22 of the heat exchange coil 2 is connected with a plurality of first-order steam pipes 311. One first-order steam pipe 311 is connected with a pressurization tank 4. A second-order steam pipe 321 is connected to the pressurization tank 4. A second-order pressure control valve 322 and a pressure gauge 323 are arranged on the second-order steam pipe 321; and a first-order pressure control valve 312 is connected to the first-order steam pipe 311. Multiple pressurization tanks 4 are grouped into heat exchange groups with two pressurization tanks 4 as one group. If one of the two first-order pressure control valves 312 in the same heat exchange group is in the open state, the other is in the closed state.

[0042] In addition, referring to Figure 1, a heat transfer plate 5 is hermetically and slidably arranged in the pressure vessel 4. The heat transfer plate 5 is made of a high thermal conductivity material. The heat transfer plate 5 divides the inner cavity of the pressure vessel 4 into a pressure-receiving area 41 and a pressurizing area 42. The first-order steam pipe 311 and the second-order steam pipe 321 are both connected to the pressure-receiving area 41. And a pressure-regulating pipe 43 is connected to the pressure vessel 4, one end of which is communicated with the pressurizing area 42 and the other end is communicated with the energy storage tank 1. A pressurizing mechanism is arranged on the energy storage tank 1 for transporting the molten salt therein to the pressure vessel 4 through the pressure-regulating pipe 43.

[0043] In this way, the peak shaving power or the high-temperature steam of the thermal power unit can be used to heat the molten salt in the energy storage tank 1 through the heat storage mechanism 11. The energy storage tank 1 stores the high-temperature molten salt in a heat-insulated manner. The high-temperature molten salt is selected as the carrier of thermal energy to complete heat storage due to its high heat capacity and thermal stability.

[0044] When heat release is required, a low-temperature medium can be introduced into the low-temperature medium inlet 21 of the heat exchange coil 2. The low-temperature medium can be water or other media. During the process of the low-temperature medium flowing in the heat exchange coil 2, the high-temperature molten salt in the energy storage tank 1 heats the low-temperature medium in the heat exchange coil 2 into high-temperature steam, which is discharged from a plurality of first-order steam pipes 311.

[0045] Specifically, referring to Figure 1 , the high-temperature steam is introduced into the corresponding pressure vessel 4 through one of the first-order steam pipes 311. At this time, the volume of the pressure-receiving area 41 increases, and the heat transfer plate 5 moves into the pressurizing area 42. The molten salt in the pressurizing area 42 can be transported back to the energy storage tank 1 through the pressure-regulating pipe 43 to be mixed with the high-temperature molten salt in the energy storage tank 1. When the high-temperature steam in the pressure-receiving area 41 is full, the pressurizing mechanism continuously transports the high-temperature molten salt in the energy storage tank 1 to the pressurizing area 42. The heat transfer plate 5 moves towards the pressure-receiving area 41. The high-temperature molten salt in the pressurizing area 42 reheats the high-temperature steam in the pressure-receiving area 41 through the heat transfer plate 5. Thus, the high-temperature steam in the pressure-receiving area 41 is compressed and reheated to form high-parameter steam. When the pressure gauge 323 detects that the pressure of the high-parameter steam reaches the standard, the second-order pressure control valve 322 is opened, and the high-parameter steam is discharged from the second-order steam pipe 321. At this time, a compression process is completed. The high-temperature steam can be reheated into high-parameter steam, and the circulation of the high-temperature molten salt between the pressure vessel 4 and the energy storage tank 1 can be promoted.

[0046] Therefore, by alternately completing the above compression process through multiple parallel pressure vessels 4, high-parameter steam can be continuously discharged from a plurality of second-order steam pipes 321 for use by equipment such as steam turbines or generators. And since the high-temperature molten salt is separated from the high-temperature steam by the heat transfer plate 5, there is no need to desalt the high-parameter steam, and the heat loss during the treatment process can also be reduced, effectively ensuring the thermal efficiency of the heat exchange system.

[0047] In addition, referring to Figure 1, one end of the pressure regulating pipe 43 communicating with the energy storage tank 1 is located in the middle and lower part of the energy storage tank 1. Specifically, it should be located in the high-temperature molten salt layer in the energy storage tank 1. It should also be clearly stated that the volume of the energy storage tank 1 is much larger than that of the pressurizing tank 4 to meet the supply of high-temperature molten salt in the energy storage tank 1 to the high-temperature molten salt required in multiple pressurizing tanks 4. The pressurizing mechanism includes an air pump 61 communicating with an inert gas source and an air charging pipe 62 connected to the output end of the air pump 61. The air charging pipe 62 extends to the bottom of the energy storage tank 1; a plurality of flow equalizing pipes 63 all communicating with the air charging pipe 62 are arranged above the inner bottom wall of the energy storage tank 1.

[0048] Correspondingly, a pressure relief pipe 71 is connected to the upper part of the energy storage tank 1. A pressure relief valve 72 is arranged on the pressure relief pipe 71. The bottom of the pressure relief pipe 71 is located in the energy storage tank 1 but above the high-temperature molten salt layer.

[0049] In this way, the inert gas can be transported to the bottom wall of the energy storage tank 1 through the air pump 61 via the air charging pipe 62. The arrangement of the plurality of flow equalizing pipes 63 can make the air charging at the bottom of the energy storage tank 1 more uniform. After charging, the inert gas forms bubbles in the high-temperature molten salt and floats upward. During the upward floating process, the bubbles will drive the surrounding molten salt to move together, forming convection, thereby promoting the heat transfer between the heat exchange coil 2 and the mixing of the molten salt. In particular, it can promote the mixing effect of the molten salt that has undergone pressurization and reheating heat exchange and is back-fed from the pressure regulating pipe 43 with the high-temperature molten salt in the energy storage tank 1, so that the overall temperature uniformity of the high-temperature molten salt in the energy storage tank 1 is good.

[0050] When an appropriate amount of inert gas is introduced into the energy storage tank 1, the air pressure in the energy storage tank 1 increases, and the high-temperature molten salt can be transported to the pressurizing area 42 of the pressurizing tank 4 that has stopped charging high-temperature steam through the pressure regulating pipe 43. At the same time, the molten salt in the pressurizing area 42 of another pressurizing tank 4 in the same heat exchange group is also squeezed out and back-fed to the energy storage tank 1, which can also promote the increase of the internal pressure in the energy storage tank 1. In this way, the high-temperature molten salt in the energy storage tank 1 can be alternately circulated in the two pressurizing tanks 4 of the same heat exchange group, that is, the continuous supply of high-temperature molten salt required for multiple heat exchange groups can be realized; moreover, only inert gas needs to be filled into the air charging pipe 62 at the initial stage of system startup during this supply process. After the two compression processes of each heat exchange group alternate and operate stably, there is no need to continuously supply inert gas to the energy storage tank 1. Only when the internal pressure in the energy storage tank 1 decreases after the consumption of inert gas during the system operation process, inert gas needs to be replenished.

[0051] In addition, in order to more sensitively control the orderly alternate operation of the two compression processes in the same heat exchange group, referring to Figure 1 , an electromagnetic reversing check valve 44 is arranged on the pressure regulating pipe 43. When the high-temperature steam is continuously introduced into the pressure receiving area 41 through the first-order steam pipe 311, the electromagnetic reversing check valve 44 controls the liquid flow in the pressure regulating pipe 43 to only flow from the pressurizing tank 4 to the energy storage tank 1;

[0052] When the high-temperature steam supply to the compression zone 41 stops, that is, when the first-stage pressure control valve 312 closes, the electromagnetic reversing check valve 44 controls the liquid flow in the pressure regulating pipe 43 to flow only from the energy storage tank 1 to the pressurization tank 4.

[0053] Therefore, after connecting the first-stage pressure control valve 312, the second-stage pressure control valve 322, and the electromagnetic reversing check valve 44 to the controller, when the controller controls the first-stage control valve to open and the second-stage control valve to close, the controller also controls the electromagnetic reversing check valve 44 to reverse so that the liquid flow in the pressure regulating pipe 43 flows only from the pressurization tank 4 to the energy storage tank 1. That is, at this time, high-temperature steam continues to be introduced into the compression zone 41 to discharge the molten salt in the pressurization zone 42; when the controller controls the first-stage control valve and the second-stage control valve to close, the controller also controls the electromagnetic reversing check valve 44 to reverse so that the liquid flow in the pressure regulating pipe 43 flows only from the energy storage tank 1 to the pressurization tank 4. That is, at this time, the high-temperature molten salt in the pressurization tank 4 is transported to the pressurization zone 42 to compress the high-temperature steam in the compression zone 41.

[0054] Most importantly, in order to promote the reheating effect of the high-temperature molten salt in the pressurization zone 42 of the pressurization tank 4 on the high-temperature steam in the compression zone 41, referring to Figure 1 and Figure 2 , a plurality of through holes 51 are formed through the heat transfer plate 5. A heat conduction rod 52 is hermetically and slidably arranged in the through holes 51. Limiting pieces 53 are fixedly connected to both ends of the heat conduction rod 52. The heat conduction rod 52 can be a solid or hollow aluminum rod, copper rod, etc.; and a sealing sleeve 54 made of polytetrafluoroethylene is fixed on the hole wall of the through hole 51 of the heat transfer plate 5. The heat conduction rod 52 is slidably arranged in the sealing sleeve 54; similarly, a sealing ring 55 made of polytetrafluoroethylene is also embedded on the outer periphery of the heat transfer plate 5.

[0055] Polytetrafluoroethylene has good lubricity, acid resistance, alkali resistance, and high-temperature resistance. The sealing sleeves 54 and sealing rings 55 made of it can seal the gaps between the heat transfer plate 5 and the heat conduction rod 52 and between the heat transfer plate 5 and the inner wall of the pressurization tank 4, and can also provide good sliding performance, and are less affected by high temperatures, and can work in the high-temperature and high-pressure environment of the pressurization tank 4 for a long time.

[0056] The arrangement of the heat conduction rods 52 on the heat transfer plate 5 can further increase the heat transfer area between the high-temperature steam in the compression zone 41 and the high-temperature molten salt in the pressurization zone 42, thereby improving the heat transfer efficiency of the high-temperature molten salt in the heating tank; and by the slidable arrangement of the heat conduction rods 52 on the heat transfer plate 5, it can ensure as much as possible the discharge of the molten salt after heat exchange in the pressurization zone 42 and the compression of the high-temperature steam in the compression zone 41 to the required pressure.

[0057] When the heat transfer plate 5 moves upward in the pressure vessel 4 and compresses the high-pressure steam, most of the heat conduction rods 52 are located in the compression zone 41, which can make the reheating of the high-temperature molten salt to the high-temperature steam in the compression zone 41 more uniform. And as the heat transfer plate 5 continues to move after the heat conduction rod 52 abuts against the inner top wall of the pressure vessel 4, the length of the heat conduction rod 52 in the pressurization zone 42 gradually increases, so that as much heat as possible of the high-temperature molten salt in the pressurization zone 42 can be transferred to the compression zone 41, so as to promote the process of the high-temperature steam in the compression zone 41 being compressed and reheated to form high-parameter steam.

[0058] When the heat transfer plate 5 moves downward in the pressure vessel 4 and discharges the molten salt in the pressurization zone 42, most of the heat conduction rods 52 are located in the pressurization zone 42, and the waste heat in the molten salt can continue to be used to heat a small amount of high-temperature steam; as the heat transfer plate 5 continues to move downward after the heat conduction rod 52 abuts against the inner bottom wall of the pressure vessel 4, the length of the heat conduction rod 52 in the compression zone 41 gradually increases, which can reduce the probability of excessive heat transfer of the high-temperature steam in the compression zone 41 to the remaining molten salt in the pressurization zone 42, and then maintain a high heat exchange efficiency of the system.

[0059] The embodiment of the present application discloses an efficient heat exchange process for an energy storage system. Based on the above-mentioned efficient heat exchange system for an energy storage system, refer to Figure 1 , which includes the following steps:

[0060] Utilize the peak shaving power or the high-temperature steam of the thermal power unit to heat the molten salt in the energy storage tank 1 through the heat storage mechanism 11, and the energy storage tank 1 insulates and stores the high-temperature molten salt to complete heat storage;

[0061] When heat release is required, a low-temperature medium is introduced into the low-temperature medium inlet 21 of the heat exchange coil 2, and the high-temperature molten salt in the energy storage tank 1 heats the low-temperature medium in the heat exchange coil 2 into high-temperature steam and discharges it from the first-order steam pipe 311;

[0062] The high-temperature steam is introduced into the corresponding pressure vessel 4 through one of the first-order steam pipes 311. The volume of the compression zone 41 increases, and the heat transfer plate 5 moves into the pressurization zone 42 to return the molten salt in the pressurization zone 42 to the energy storage tank 1 through the pressure regulating pipe 43; after the compression zone 41 is filled with high-temperature steam, the pressurizing mechanism transports the high-temperature molten salt in the energy storage tank 1 to the pressurization zone 42, the heat transfer plate 5 moves towards the compression zone 41, and the high-temperature steam in the compression zone 41 is compressed and reheated to form high-parameter steam and discharged from the second-order steam pipe 321; to complete one compression process;

[0063] Multiple parallel pressure vessels 4 alternately complete the above compression process, so that a plurality of second-order steam pipes 321 continuously discharge high-parameter steam.

[0064] The implementation principle of the efficient heat exchange system for an energy storage system in the embodiment of the present application is:

[0065] The peak shaving power or the high-temperature steam of the thermal power unit can be used to heat the molten salt in the energy storage tank 1 through the heat storage mechanism 11. The energy storage tank 1 stores the high-temperature molten salt in a heat-insulated manner to complete heat storage.

[0066] When heat release is required, a low-temperature medium is introduced into the low-temperature medium inlet 21 of the heat exchange coil 2. During the process of the low-temperature medium flowing in the heat exchange coil 2, the high-temperature molten salt in the energy storage tank 1 heats the low-temperature medium in the heat exchange coil 2 into high-temperature steam, which is discharged from a plurality of first-order steam pipes 311. The high-temperature steam is introduced into the corresponding pressurizing tank 4 through one of the first-order steam pipes 311. The volume of the pressure-receiving area 41 increases, and the heat transfer plate 5 moves into the pressurizing area 42, and the molten salt in the pressurizing area 42 can be returned to the energy storage tank 1 through the pressure-regulating pipe 43 to be mixed with the high-temperature molten salt in the energy storage tank 1; when the high-temperature steam in the pressure-receiving area 41 is full, the charging pipe 62 fills the energy storage tank 1 with inert gas to continuously transport the high-temperature molten salt in the energy storage tank 1 to the pressurizing area 42. The heat transfer plate 5 moves towards the pressure-receiving area 41, and the high-temperature molten salt in the pressurizing area 42 reheats the high-temperature steam in the pressure-receiving area 41 through the heat transfer plate 5. Thus, the high-temperature steam in the pressure-receiving area 41 is compressed and reheated to form high-parameter steam. When the pressure gauge 323 detects that the pressure of the high-parameter steam reaches the standard, the second-order pressure control valve 322 opens, and the high-parameter steam is discharged from the second-order steam pipe 321; at this time, a compression process is completed, the high-temperature steam can be reheated into high-parameter steam, and the circulation of the high-temperature molten salt between the pressurizing tank 4 and the energy storage tank 1 can be promoted.

[0067] Since the high-temperature molten salt is separated from the high-temperature steam by the heat transfer plate 5, there is no need to desalt the high-parameter steam, and the heat loss during the treatment process can also be reduced, effectively ensuring the thermal efficiency of the heat exchange system. Moreover, after introducing an appropriate amount of inert gas into the energy storage tank 1, the air pressure in the energy storage tank 1 increases, and the high-temperature molten salt can be transported to the pressurizing area 42 of the pressurizing tank 4 that has stopped charging high-temperature steam through the pressure-regulating pipe 43. At the same time, the molten salt in the pressurizing area 42 of another pressurizing tank 4 in the same heat exchange group is also squeezed out and returned to the energy storage tank 1, which can also promote the increase of the internal pressure in the energy storage tank 1. In this way, the high-temperature molten salt in the energy storage tank 1 can be circulated alternately in the two pressurizing tanks 4 of the same heat exchange group, that is, the continuous supply of the high-temperature molten salt required for multiple heat exchange groups can be realized; and only the inert gas needs to be filled into the charging pipe 62 at the initial stage of the system startup during this supply process. After the two compression processes of each heat exchange group are alternately operated smoothly, there is no need to continuously supply inert gas to the energy storage tank 1, and only when the internal pressure in the energy storage tank 1 decreases after the inert gas is consumed during the system operation, the inert gas needs to be replenished.

[0068] Unless otherwise defined, the technical terms or scientific terms used in this application shall have the ordinary meanings as understood by those of ordinary skill in the art to which this application pertains. The terms "first", "second", "third" and similar terms used in the specification and claims of this application do not denote any order, quantity or importance, but are merely used to distinguish different components. Similar terms such as "a" or "an" do not denote a quantity limitation, but rather indicate the presence of at least one. Similar terms such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. Terms such as "upper", "lower", "left" and "right" are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationships may also change accordingly.

[0069] The above are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape and principle of this application shall be covered within the protection scope of this application.

Claims

1. A high-efficiency heat exchange system for an energy storage system, comprising an energy storage tank (1) filled with molten salt, wherein a heat exchange coil (2) is arranged in the energy storage tank (1), wherein one end of the heat exchange coil (2) is a low-temperature medium inlet (21) and the other end is a high-temperature steam outlet (22), and the energy storage tank (1) is also provided with a heat storage mechanism (11) for heating the molten salt in the energy storage tank (1), characterized in that: The high-temperature steam outlet (22) of the heat exchange coil (2) is connected to a plurality of first-order steam pipes (311), one of the first-order steam pipes (311) is connected to a pressure tank (4), the pressure tank (4) is connected to a second-order steam pipe (321), and the second-order steam pipe (321) is provided with a second-order pressure control valve (322); A heat transfer plate (5) is sealingly and slidably provided in the pressurized tank (4), the heat transfer plate (5) dividing the inner cavity of the pressurized tank (4) into a pressure zone (41) and a pressurizing zone (42), and the first-order steam pipe (311) and the second-order steam pipe (321) are both connected to the pressure zone (41); The pressurized tank (4) is connected to a pressure regulating pipe (43) having one end connected to the pressurized area (42) and the other end connected to the energy storage tank (1); the energy storage tank (1) is provided with a pressurizing mechanism for transporting the molten salt therein to the pressurized tank (4) via the pressure regulating pipe (43); The heat transfer plate (5) is provided with a plurality of through holes (51), a heat conducting rod (52) is sealingly and slidably arranged in the through holes (51), and both ends of the heat conducting rod (52) are fixedly connected to limiting plates (53); As the heat transfer plate (5) continues to move after the heat conducting rod (52) contacts the inner top wall of the pressurized tank (4), the length of the heat conducting rod (52) in the pressurized zone (42) gradually increases, so that the heat of the high-temperature molten salt in the pressurized zone (42) can be transferred to the pressurized zone (41) as much as possible, thereby promoting the process of compressing and reheating the high-temperature steam in the pressurized zone (41) to form high-parameter steam; As the heat transfer plate (5) continues to move downward after the heat conductive rod (52) contacts the inner bottom wall of the pressurized tank (4), the length of the heat conductive rod (52) in the pressurized zone (41) gradually increases, thereby reducing the probability of excessive heat from the high-temperature steam in the pressurized zone (41) being transferred to the molten salt remaining in the pressurized zone (42), thereby maintaining a high heat exchange efficiency of the system.

2. The high-efficiency heat exchange system for an energy storage system according to claim 1, characterized in that: One end of the pressure regulating pipe (43) connected to the energy storage tank (1) is located in the lower middle part of the energy storage tank (1), and the pressurizing mechanism comprises an air pump (61) connected to an inert gas source and an air charging pipe (62) connected to an output end of the air pump (61), wherein the air charging pipe (62) extends into the energy storage tank (1).

3. The high-efficiency heat exchange system for an energy storage system according to claim 2, characterized in that: The inflation pipe (62) extends to the bottom of the energy storage tank (1).

4. The high-efficiency heat exchange system for an energy storage system according to claim 3, characterized in that: A plurality of flow equalizing tubes (63) each in communication with the inflation tube (62) are arranged above the inner bottom wall of the energy storage tank (1).

5. The high-efficiency heat exchange system for an energy storage system according to claim 1, characterized in that: The pressure regulating pipe (43) is provided with an electromagnetic reversing check valve (44). When high-temperature steam is continuously introduced into the pressure zone (41) by the first-stage steam pipe (311), the electromagnetic reversing check valve (44) controls the liquid flow in the pressure regulating pipe (43) to flow only from the pressurizing tank (4) to the energy storage tank (1); When the high-temperature steam stops flowing into the pressurized area (41), the electromagnetic reversing one-way valve (44) controls the liquid flow in the pressure regulating pipe (43) to flow only from the energy storage tank (1) to the pressurized tank (4).

6. A high-efficiency heat exchange system for an energy storage system according to any one of claims 1 to 5, characterized in that: The heat transfer plate (5) has a sealing sleeve (54) made of polytetrafluoroethylene fixed on the wall of the through hole (51), and the heat conducting rod (52) is slidably disposed in the sealing sleeve (54).

7. The high-efficiency heat exchange system for an energy storage system according to claim 2, characterized in that: The upper portion of the energy storage tank (1) is connected to a pressure relief pipe (71), and a pressure relief valve (72) is provided on the pressure relief pipe (71).

8. The high-efficiency heat exchange system for an energy storage system according to claim 1, characterized in that: The first-order steam pipe (311) is connected to a first-order pressure control valve (312); two of the plurality of pressurized tanks (4) form a heat exchange group; and when one of the two first-order pressure control valves (312) in the same heat exchange group is in an open state, the other is in a closed state.

9. A high-efficiency heat exchange process for an energy storage system, based on a high-efficiency heat exchange system for an energy storage system as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: The molten salt in the energy storage tank (1) is heated by using the peak load electricity or the high-temperature steam of the thermal power unit through the heat storage mechanism (11), and the energy storage tank (1) stores the high-temperature molten salt in a heat-insulating manner to complete the heat storage; When heat release is required, a low-temperature medium is introduced into the low-temperature medium inlet (21) of the heat exchange coil (2), and the high-temperature molten salt in the energy storage tank (1) heats the low-temperature medium in the heat exchange coil (2) into high-temperature steam, which is then discharged from the first-stage steam pipe (311); High-temperature steam is introduced into the corresponding pressurized tank (4) through one of the first-stage steam pipes (311), the volume of the pressurized zone (41) increases, and the heat transfer plate (5) moves toward the pressurized zone (42) to return the molten salt in the pressurized zone (42) to the energy storage tank (1) through the pressure regulating pipe (43); after the high-temperature steam in the pressurized zone (41) is filled, the pressurizing mechanism transports the high-temperature molten salt in the energy storage tank (1) to the pressurized zone (42), and the heat transfer plate (5) moves toward the pressurized zone (41), and the high-temperature steam in the pressurized zone (41) is compressed and reheated to form high-parameter steam, which is then discharged from the second-stage steam pipe (321), thereby completing a compression process; The plurality of parallel-connected pressurized tanks (4) alternately complete the above-mentioned compression process, so that the plurality of second-stage steam pipes (321) discharge high-parameter steam in succession.

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