An electric heating molten salt energy storage heating heat exchange station system

Abstract

The application discloses a kind of electric heating molten salt energy storage heating heat exchange station systems, including molten salt energy storage heat exchange system and heating heat exchange system, two subsystems are connected by pipeline;The molten salt energy storage heat exchange system includes high-temperature molten salt tank, low-temperature molten salt tank, high-temperature molten salt tank electric heater, low-temperature molten salt tank electric heater, high-temperature molten salt frequency conversion pump, low-temperature molten salt frequency conversion pump and the like;The heating heat exchange system includes steam-water heat exchanger, water-water heat exchanger, heat network circulating pump A, heat network circulating pump B, heat network water supply pump A, heat network water supply pump B, heat network water supply flow meter and heat network water supply tank and the like.The application can be distributed in the clean heating mode of user side, can be heated by molten salt energy storage at night low peak electricity price, is heated by molten salt heat exchange into superheated steam, and superheated steam is heated after being returned to heat exchange station and is supplied to user, this mode not only can guarantee heating stability and economy, can also be applicable to centralized heating area and dispersed heating area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heating and heat exchange stations, in particular to a system of an electric heating molten salt energy storage heating and heat exchange station. BACKGROUND

[0002] Currently, some areas need to close small coal-fired boilers as soon as possible, and many areas have the problem that the heat source power plant is far away from the residential area. Some areas even have no heating source, especially some small towns, which are difficult to realize winter heating through central heating. This contradiction can be summarized in three aspects. First, under the double carbon target, some areas lack central heating sources, but small coal-fired boilers have to be closed continuously, so it is urgent to find alternative heat sources. Second, some areas do not have the conditions for central heating, and the original burning coal or burning wood method is used for self-provided heating, which causes serious environmental pollution, but it is difficult to change this situation at present. Third, if long-distance pipe networks are used to supply heat to scattered towns, not only the heat loss of long-distance pipe networks is large, but also the heating area is small, and the economy of heating is poor. In summary, finding a heating system distributed on the user side not only needs to be suitable for central heating systems, but also needs to be suitable for small towns with scattered heating, and at the same time, it needs to have clean energy and good economy. This heating mode is the optimal way to solve the current contradiction of residential heating. SUMMARY

[0003] The purpose of the present application is to provide a system of an electric heating molten salt energy storage heating and heat exchange station, which is a clean heating method that can be distributed on the user side. The molten salt can be heated and stored during the off-peak hours at night, and the overheat steam can be obtained by heat exchange between the molten salt and the heating and heat exchange system during the heating period. The overheat steam is used to heat the water in the water tank through heat exchange, and then the water is supplied to the user. This method not only ensures the stability and economy of heating, but also is suitable for central heating areas and scattered heating areas.

[0004] To achieve the above purpose, the present application adopts the following technical scheme:

[0005] A system of an electric heating molten salt energy storage heating and heat exchange station, comprising a molten salt energy storage and heat exchange system and a heating and heat exchange system, and the two subsystems are connected through a pipeline;

[0006] The molten salt energy storage and heat exchange system comprises a high-temperature molten salt tank, a low-temperature molten salt tank, a high-temperature molten salt tank electric heater, a low-temperature molten salt tank electric heater, a high-temperature molten salt frequency conversion pump, a low-temperature molten salt frequency conversion pump, a molten salt-water pre-heater, a molten salt-water evaporator, a molten salt-water superheater, a molten salt-water recirculation pump, a molten salt-water heat exchange feed water pump and a molten salt-water heat exchange water tank;

[0007] The high-temperature molten salt tank utilizes off-peak electricity of a power grid, heats molten salt through a high-temperature molten salt tank electric heater, pressurizes the heated molten salt through a high-temperature molten salt frequency conversion pump, and then sequentially passes through a molten salt-water overheater, a molten salt-water evaporator and a molten salt-water pre-heater for heat exchange.

[0008] The molten salt-water heat exchange water tank pressurizes hot water through a molten salt-water heat exchange water pump, and then sends the hot water to a molten salt-water pre-heater water side, a molten salt-water evaporator water side, and a molten salt-water recirculation pump.

[0009] The heating heat exchange system comprises a steam-water heat exchanger, a water-water heat exchanger, a heat network circulating pump A, a heat network circulating pump B, a heat network water supplement pump A, a heat network water supplement pump B, a heat network water supply flow meter, a heat network return water flow meter and a heat network water supplement tank.

[0010] The heat network return water flow meter counts the flow of the heat network circulating water, and the heat network circulating water return water temperature is designed to be 40 DEG C. The circulating water supply temperature after passing through the water-water heat exchanger and the steam-water heat exchanger is designed to be 70 DEG C. The heat network circulating water is pressurized through the heat network circulating pump A or the heat network circulating pump B, and then passes through the heat network water supply flow meter to heat the user. The heat network water supplement tank supplements the water amount of the heat network circulating water through the heat network water supplement pump A or the heat network water supplement pump B.

[0011] The high-temperature molten salt tank electric heater heats the molten salt, and maintains the temperature of the high-temperature molten salt tank to be 370 DEG C.

[0012] The heated molten salt is pressurized to 0.5 MPa-0.7 MPa through the high-temperature molten salt frequency conversion pump.

[0013] The molten salt energy storage heat exchange system further comprises a high-temperature molten salt flow regulating valve. The pressurized molten salt passes through the high-temperature molten salt flow regulating valve, and then sequentially passes through the molten salt-water overheater, the molten salt-water evaporator and the molten salt-water pre-heater for heat exchange.

[0014] The temperature of the molten salt after sequentially passing through the molten salt-water overheater, the molten salt-water evaporator and the molten salt-water pre-heater for heat exchange is 220 DEG C.

[0015] The low-temperature molten salt tank electric heater maintains the temperature of the molten salt in the tank to be above 180 DEG C.

[0016] The further improvement of the present application is that the molten salt-water heat exchange water tank pressurizes hot water with a temperature of 80 DEG C to 1.0 MPa through a molten salt-water heat exchange water pump.

[0017] The further improvement of the present application is that the evaporated water vapor is heated through a molten salt-water superheater to generate high-temperature and high-pressure steam with a temperature of 240 DEG C.

[0018] The further improvement of the present application is that the molten salt is ternary nitric acid molten salt, specifically, potassium nitrate 53%, sodium nitrite 40%, and sodium nitrate 7%; the melting point is 142-148 DEG C, and the use temperature is 150-550 DEG C.

[0019] The further improvement of the present application is that the heat network circulating pump A and the heat network circulating pump B are used alternately in normal operation, and the heat network water supplement pump A and the heat network water supplement pump B are used alternately in normal operation.

[0020] The present application has at least the following beneficial technical effects:

[0021] 1. The molten salt is heated by using off-peak electricity, and the energy is stored in the molten salt storage tank, which can not only well absorb the consumption of new energy such as night wind power generation, but also reduce the use of small coal-fired boilers for heating, and is a clean heating method.

[0022] 2. The heating heat exchange station of the present application has wider applicability, and can be applied not only to large-scale central heating projects, but also to remote towns with less personnel and small heating area.

[0023] 3. The heating heat exchange station of the present application can be distributed in the center of the user side, which can reduce the investment cost of the heat network.

[0024] 4. The present application uses ternary nitrate with lower melting point as the molten salt energy storage and heat exchange medium, which has comparable stability compared with binary nitrate, and can also reduce the power consumption of electric heat tracing. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of a system of the electric heating molten salt energy storage heating heat exchange station of the present application.

[0026] Explanation of reference signs:

[0027] 1. High temperature molten salt tank electric heater, 2. Low temperature molten salt tank electric heater, 3. High temperature molten salt tank, 4. Low temperature molten salt tank, 5. High temperature molten salt frequency conversion pump, 6. Low temperature molten salt frequency conversion pump, 7. Molten salt-water superheater, 8. Molten salt-water evaporator, 9. Molten salt-water preheater, 10. Molten salt-water heat exchange feed water pump, 11. Molten salt-water recirculation pump, 12. High temperature molten salt flow regulating valve, 13. Steam-water heat exchanger, 14. Water-water heat exchanger, 15. Heat network circulating pump A, 16. Heat network circulating pump B, 17. Heat network make-up water pump A, 18. Heat network make-up water pump B, 19. Heat network water supply flow meter, 20. Heat network return water flow meter, 21. Molten salt-water heat exchange water tank, 22. Heat network make-up water tank. DETAILED DESCRIPTION

[0028] The embodiments of the present application will be further described below with reference to the drawings.

[0029] Referring to the drawings Figure 1 The present application provides an electric heating molten salt energy storage heating and heat exchange station system, which aims to solve the problem of applying a more widely used clean energy heating method, including a molten salt energy storage heat exchange system and a heating and heat exchange system, the two subsystems being connected through pipelines; the molten salt energy storage heat exchange system is composed of a high temperature molten salt tank electric heater 1, a low temperature molten salt tank electric heater 2, a high temperature molten salt tank 3, a low temperature molten salt tank 4, a high temperature molten salt frequency conversion pump 5, a low temperature molten salt frequency conversion pump 6, a molten salt-water superheater 7, a molten salt-water evaporator 8, a molten salt-water preheater 9, a molten salt-water heat exchange feed water pump 10, a molten salt-water recirculation pump 11, a high temperature molten salt flow regulating valve 12, and a molten salt-water heat exchange water tank 21; and the heating and heat exchange system is composed of a steam-water heat exchanger 13, a water-water heat exchanger 14, a heat network circulating pump A 15, a heat network circulating pump B 16, a heat network make-up water pump A 17, a heat network make-up water pump B 18, a heat network water supply flow meter 19, a heat network return water flow meter 20, and a heat network make-up water tank 22.

[0030] The high temperature molten salt tank 3 utilizes off-peak power from the power grid, heats the molten salt through the high temperature molten salt tank electric heater 1, and maintains the temperature of the high temperature molten salt tank 3 at 370℃; the heated molten salt is pressurized to 0.5MPa-0.7MPa through the high temperature molten salt frequency conversion pump 5, and then sequentially passes through the molten salt-water superheater 7, the molten salt-water evaporator 8, and the molten salt-water preheater 9 for heat exchange, and the temperature of the molten salt after heat exchange is 220℃. The molten salt after heat exchange returns to the low temperature molten salt tank 4, the low temperature molten salt tank electric heater 2 maintains the temperature of the molten salt in the tank above 180℃, and the low temperature molten salt tank 4 can send the molten salt to the high temperature molten salt tank 3 through the low temperature molten salt frequency conversion pump 6.

[0031] The molten salt-water heat exchange water tank 21 sends the hot water with a temperature of 80℃ to the water side of the molten salt-water pre-heater 9 after being pressurized to 1.0MPa by the molten salt-water heat exchange water pump 10, and then to the water side of the molten salt-water evaporator 8, and the water that has not reached the saturated state is pumped back to the water side of the molten salt-water pre-heater 9 by the molten salt-water recirculation pump 11, and the evaporated water vapor is heated by the molten salt-water superheater 7 to generate high-temperature and high-pressure steam with a temperature of 240℃.

[0032] The molten salt is ternary nitric acid molten salt, specifically, potassium nitrate 53%, sodium nitrite 40%, and sodium nitrate 7%; the melting point is 142-148℃, and the use temperature is 150-550℃.

[0033] The hot network return water flow meter 20 counts the flow of the hot network circulating water, the hot network circulating water return water temperature is designed to be 40℃, the circulating water supply temperature after passing through the water-water heat exchanger 14 and the steam-water heat exchanger 13 is designed to be 70℃, and the hot network circulating water is pressurized by the hot network circulating pump A 15 or the hot network circulating pump B 16, and then is supplied to the heating user through the hot network supply flow meter 19.

[0034] The hot network circulating pump A 15 or the hot network circulating pump B 16 pressurizes the hot network circulating water, the hot network make-up water is supplied by the hot network make-up pump A 17 and the hot network make-up pump B 18 according to the difference between the hot network supply flow meter 19 and the hot network make-up flow meter, the supplied heating hot network circulating water goes to the user, and the used hot network circulating water return water passes through the water-water heat exchanger 14 and the steam-water heat exchanger 13 again to be pressurized by the hot network circulating pump A 15 or the hot network circulating pump B 16 after the temperature is raised, so as to achieve circulation.

[0035] The hot network circulating pump A 15 and the hot network circulating pump B 16 are used alternately in normal operation, and the hot network make-up pump A 17 and the hot network make-up pump B 18 are used alternately in normal operation.

[0036] The hot network make-up water tank 22 supplies water to the hot network circulating water by the hot network make-up pump A 17 or the hot network make-up pump B 18.

[0037] The use and method of the system are further described as follows:

[0038] Molten salt energy storage mode. When the night power load is low, the low-temperature molten salt variable frequency pump 6 sends the molten salt in the low-temperature molten salt tank 4 to the high-temperature molten salt tank 3, and the electric heater in the high-temperature molten salt tank 3 heats the molten salt to 370℃, so as to achieve the function of molten salt energy storage.

[0039] Heating mode. When the heating system is running, the molten salt outlet pressure of the high-temperature molten salt tank 3 is 0.5-0.7 MPa, and the molten salt flow is adjusted according to the heating demand. After molten salt-water heat exchange, the temperature is reduced from 370°C to 220°C. The water outlet pressure of the molten salt-water heat exchange water tank 21 is 1.0 MPa, and the water is heated from 80°C to 240°C, and the water changes from liquid to high-temperature high-pressure superheated steam. The high-temperature high-pressure steam passes through the steam-water heat exchanger 13 and the water-water heat exchanger 14, and the temperature is reduced to 80°C, while the temperature of the heat network circulating water is increased from 40°C to 70°C after heating. The heating system continues to run to ensure stable heating demand, and the molten salt in the high-temperature molten salt tank 3 is gradually returned to the low-temperature molten salt tank 4. The electric heater of the low-temperature molten salt tank 4 ensures that the temperature of the molten salt in the tank is maintained above 180°C. During the low-peak period of the power grid at night, the molten salt in the low-temperature molten salt tank 4 is sent to the high-temperature molten salt tank 3 for heating.

[0040] The purpose of the present application is to provide a method, a specific system adjustment and operation strategy, and related knowledge should be familiar to professional technicians.

[0041] The above is only the preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can make equivalent replacement or change according to the technical solution and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A system of an electrically heated molten salt energy storage heating heat exchange station, characterized in that, The system comprises a molten salt energy storage heat exchange system and a heating heat exchange system, and the two subsystems are connected through pipelines. The molten salt energy storage heat exchange system comprises a high-temperature molten salt tank, a low-temperature molten salt tank, a high-temperature molten salt tank electric heater, a low-temperature molten salt tank electric heater, a high-temperature molten salt frequency conversion pump, a low-temperature molten salt frequency conversion pump, a molten salt-water pre-heater, a molten salt-water evaporator, a molten salt-water superheater, a molten salt-water recirculation pump, a molten salt-water heat exchange feed water pump and a molten salt-water heat exchange water tank. The high-temperature molten salt tank utilizes off-peak power from a power grid to heat molten salt through the high-temperature molten salt tank electric heater, and the heated molten salt is pressurized through the high-temperature molten salt frequency conversion pump, and then sequentially passes through the molten salt-water superheater, the molten salt-water evaporator and the molten salt-water pre-heater for heat exchange. The molten salt is ternary nitric acid molten salt, specifically, 53% of potassium nitrate, 40% of sodium nitrite and 7% of sodium nitrate; the melting point is 142-148℃, and the use temperature is 150-550℃. The molten salt-water heat exchange water tank pressurizes hot water at a temperature of 80℃ through the molten salt-water heat exchange feed water pump, and then sends the hot water to the water side of the molten salt-water pre-heater, and then to the water side of the molten salt-water evaporator. The heating heat exchange system comprises a steam-water heat exchanger, a water-water heat exchanger, a heat network circulating pump A, a heat network circulating pump B, a heat network water supplement pump A, a heat network water supplement pump B, a heat network water supply flow meter, a heat network return water flow meter and a heat network water supplement tank.

2. The system of claim 1, wherein the system further comprises a heat exchanger. The heat network return water flow meter counts the flow of the heat network circulating water, and the heat network circulating water return water temperature is designed to be 40℃, and the circulating water supply temperature after passing through the water-water heat exchanger and the steam-water heat exchanger is designed to be 70℃.

3. The system of claim 1, wherein the system further comprises a heat exchanger. The high-temperature molten salt tank electric heater heats the molten salt, and maintains the temperature of the high-temperature molten salt tank to be 370℃.

4. The system of claim 1, wherein the system further comprises a heat exchanger. The heated molten salt is pressurized to 0.5MPa-0.7MPa through the high-temperature molten salt frequency conversion pump.

5. The system of claim 1, wherein the system further comprises a heat exchanger. The temperature of the molten salt after sequentially passing through the molten salt-water superheater, the molten salt-water evaporator and the molten salt-water pre-heater for heat exchange is 220℃.

6. The system of claim 1, wherein the system further comprises a heat exchanger. The low-temperature molten salt tank electric heater maintains the temperature of the molten salt in the tank to be above 180℃.

7. The system of claim 1, wherein the system further comprises a heat exchanger. The molten salt-water heat exchange water tank pressurizes hot water at a temperature of 80℃ to 1.0MPa through the molten salt-water heat exchange feed water pump.

8. The system of claim 1, wherein the system further comprises a heat exchanger. The steam after evaporation is heated through the molten salt-water superheater to generate high-temperature and high-pressure steam at a temperature of 240℃. The heat network circulating pump A and the heat network circulating pump B are used alternately in normal operation, and the heat network water supplement pump A and the heat network water supplement pump B are used alternately in normal operation.

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