Nuclear power peak regulation fused salt heat storage and steam supply device and system

Abstract

The invention relates to the technical field of fused salt heat storage, in particular to a nuclear power peak regulation fused salt heat storage and steam supply device and system. The device comprises a feed water preheating system, a fused salt heat storage system and a steam generation system, the feed water preheating system comprises a feed water conveying structure and a feed water preheater, the fused salt heat storage system comprises a cold fused salt storage tank, a fused salt electric heater and a hot fused salt storage tank which are sequentially connected, and the steam generation system comprises a deaerator and a steam generator. The water supply conveying structure and the water supply preheater are arranged on the water inlet pipe, the water supply conveying structure is connected with the deaerator, the water supply preheater is connected with the steam generator, the steam generator is connected with the deaerator, and the steam generator is connected to a heat conveying pipeline of the cold molten salt storage tank and a heat conveying pipeline of the hot molten salt storage tank in series. The peak regulation operation of nuclear power is realized, and the flexibility is improved. In the off-peak electricity period, electricity is connected into the fused salt heat storage system, the low-temperature fused salt is heated, redundant electric energy can be consumed, and the output of a unit does not need to be excessively reduced.

Description

Technical Field

[0001] This invention relates to the field of molten salt thermal energy storage technology, specifically to a nuclear power peak-shaving molten salt thermal energy storage steam supply device and system. Background Technology

[0002] To address the complex challenges of climate change and the environment, my country's energy system is gradually transforming towards cleaner, more efficient, and more flexible power sources. Nuclear power, as a crucial baseload power source, is playing an increasingly important role in the power system. Currently, the mainstream technology for nuclear power plants is very similar to that of thermal power generation, using nuclear reactors and steam generators instead of boilers, and replacing the chemical energy of fuel combustion with the energy of nuclear fission; high-pressure water in the circuit is heated into superheated steam to drive turbines and generate electricity. The load regulation of nuclear power units primarily involves adjusting the unit's output power by controlling rod displacement, or reducing the unit's output power by directly venting steam into the condenser.

[0003] The main problem with existing nuclear power peak-shaving technologies is the poor flexibility of load regulation. Both of the above methods directly activate relevant equipment to change unit power. Due to the limitations of nuclear power unit operating characteristics, neither method can achieve large-scale, wide-range flexible peak regulation, and may also negatively impact the lifespan, safety, and economy of nuclear power units. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem of poor flexibility of load regulation methods in the prior art, thereby providing a nuclear power peak-shaving molten salt thermal storage steam supply device and system.

[0005] To address the aforementioned technical problems, this invention provides a nuclear power peak-shaving molten salt thermal storage and steam supply device, comprising: a feedwater preheating system, a molten salt thermal storage system, and a steam generation system. The feedwater preheating system includes a feedwater delivery structure and a feedwater preheater. The molten salt thermal storage system includes a cold molten salt storage tank, a molten salt electric heater, and a hot molten salt storage tank connected in sequence. The steam generation system includes a deaerator and a steam generator. The feedwater delivery structure and the feedwater preheater are located on the inlet pipe. The feedwater delivery structure is connected to the deaerator. The feedwater preheater is connected to the steam generator. The steam generator is connected to the deaerator. The steam generator is connected in series on the thermal delivery pipelines of the cold molten salt storage tank and the hot molten salt storage tank.

[0006] Furthermore, the water inlet pipe includes a first branch and a second branch, the deaerator is located on the first branch, the water preheater is located on the second branch, and one end of the second branch is connected to the steam generator.

[0007] Furthermore, a return water pipe is provided between the steam generator and the deaerator.

[0008] Furthermore, it also includes a pressurization line for connecting the deaerator and the second branch.

[0009] Furthermore, a water booster pump is installed on the booster pipeline.

[0010] Furthermore, the heat storage medium in the cold molten salt storage tank and the hot molten salt storage tank is a low-melting-point binary molten salt.

[0011] Furthermore, the molten salt thermal storage system also includes a waste heat recovery mechanism, which is connected in parallel to the connecting pipeline between the cold molten salt storage tank and the hot molten salt storage tank.

[0012] Furthermore, it also includes a regulating valve, which is located on the inlet pipe, return pipe, and connecting pipe.

[0013] Furthermore, the water supply delivery structure is a water pump.

[0014] The present invention also provides a nuclear power peak-shaving molten salt thermal storage steam supply system, including the aforementioned nuclear power peak-shaving molten salt thermal storage steam supply device.

[0015] The technical solution of this invention has the following advantages: The nuclear power peak-shaving molten salt thermal storage steam supply device provided by the present invention includes: a feedwater preheating system, a molten salt thermal storage system, and a steam generation system. The feedwater preheating system includes a feedwater conveying structure and a feedwater preheater. The molten salt thermal storage system includes a cold molten salt storage tank, a molten salt electric heater, and a hot molten salt storage tank connected in sequence. The steam generation system includes a deaerator and a steam generator. The feedwater conveying structure and the feedwater preheater are located on the inlet pipe. The feedwater conveying structure is connected to the deaerator. The feedwater preheater is connected to the steam generator. The steam generator is connected to the deaerator. The steam generator is connected in series on the thermal conveying pipelines of the cold molten salt storage tank and the hot molten salt storage tank.

[0016] The low-temperature demineralized water undergoes heat exchange in the steam generation system. The low-temperature demineralized water is heated into superheated steam for external steam supply. Some of the superheated steam is also drawn back into the deaerator to increase the temperature of the deaerated feedwater.

[0017] During off-peak electricity hours, excess electricity is fed into molten salt electric heaters to heat the molten salt from 200°C to 490°C before pumping it into hot salt tanks for storage. After the off-peak electricity hours end, the molten salt electric heaters and their pumps are shut off, ending the thermal storage process. The molten salt thermal storage system consists of 10 molten salt electric heaters, with one cold and one hot molten salt tank each installed vertically. The cold and hot salt pumps are configured with one operating and one standby pump.

[0018] During the heat release process, the salt side workflow is as follows: high-temperature molten salt is pumped from the hot molten salt storage tank into the steam generator to heat the low-temperature deoxygenated water. After heat exchange through the steam generation system, the cold molten salt is returned to the cold molten salt storage tank until the next heat storage process.

[0019] The steam-water side process of the exothermic process is as follows: the feed water from the inlet pipe is pumped into the steam generator after the feed water temperature is increased by the feed water preheater and deaerator. In the steam generator, it is heated by high-temperature molten salt to generate superheated steam at 1.0MPa / 230℃.

[0020] The nuclear power peak-shaving molten salt thermal storage steam supply device of the present invention enables peak-shaving operation of nuclear power plants and improves flexibility. During off-peak electricity periods, electricity is connected to the molten salt thermal storage system to heat the low-temperature molten salt, thereby absorbing excess electrical energy without excessively reducing the unit output. This improves energy utilization while also reducing unnecessary losses to various thermal equipment in the nuclear power unit caused by changes in operating conditions. The nuclear power peak-shaving molten salt thermal energy storage steam supply device of the present invention can achieve thermoelectric decoupling, converting excess electrical energy into energy for storage and reuse, thereby improving economic efficiency. At the same time, molten salt thermal energy storage technology has a high degree of maturity and does not require excessively high costs or restrictive construction conditions. The integrated system of nuclear power thermal energy storage further increases the dispatchability of the power grid, laying the foundation for the large-scale participation of nuclear power in grid peak shaving.

[0021] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the nuclear power peak-shaving molten salt thermal storage and steam supply device provided by the present invention.

[0024] Explanation of reference numerals in the attached figures: 1. Water supply conveying structure; 2. Water supply preheater; 3. Cold molten salt storage tank; 4. Molten salt electric heater; 5. Hot molten salt storage tank; 6. Deaerator; 7. Steam generator; 8. Inlet pipe; 9. Heat transfer pipeline; 10. First branch; 11. Second branch; 12. Return pipe; 13. Booster pipeline; 14. Water supply booster pump; 15. Waste heat recovery mechanism; 16. Regulating valve; 17. Steam pipeline. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0026] The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0027] Please see Figure 1 As shown, the present invention provides a nuclear power peak-shaving molten salt thermal storage steam supply device, comprising: a feedwater preheating system, a molten salt thermal storage system, and a steam generation system. The feedwater preheating system includes a feedwater conveying structure 1 and a feedwater preheater 2. The molten salt thermal storage system includes a cold molten salt storage tank 3, a molten salt electric heater 4, and a hot molten salt storage tank 5 connected in sequence. The steam generation system includes a deaerator 6 and a steam generator 7. The feedwater conveying structure 1 and the feedwater preheater 2 are mounted on an inlet pipe 8. The feedwater conveying structure 1 is connected to the deaerator 6. The feedwater preheater 2 is connected to the steam generator 7. The steam generator 7 is connected to the deaerator 6. The steam generator 7 is connected in series on the heat conveying pipeline 9 of the cold molten salt storage tank 3 and the hot molten salt storage tank 5.

[0028] The low-temperature demineralized water undergoes heat exchange in the steam generation system. The low-temperature demineralized water will be heated into superheated steam for external steam supply. Some of the superheated steam will also be drawn back into the deaerator 6 to increase the temperature of the deaerated feedwater.

[0029] During off-peak electricity hours, excess electricity is fed into molten salt electric heater 4 to heat the molten salt from 200℃ to 490℃ and pump it into the hot salt tank for storage. After the off-peak electricity hours end, molten salt electric heater 4 and the electric heater molten salt pump are turned off, and the heat storage process ends. The molten salt heat storage system is equipped with 10 molten salt electric heaters 4, and one cold molten salt storage tank and one hot molten salt storage tank 5 are installed vertically. The cold salt pump and the hot salt pump are configured in a 1-in-1 standby configuration.

[0030] During the heat release process, the salt side works as follows: high-temperature molten salt is pumped from the hot molten salt storage tank 5 into the steam generator 7 to heat the low-temperature deoxygenated water. After heat exchange through the steam generation system, the cold molten salt is returned to the cold molten salt storage tank 3 until the next heat storage process.

[0031] The steam-water side process of the heat release process is as follows: the feed water from the inlet pipe 8 is pumped into the steam generator 7 after the feed water is heated by the feed water preheater 2 and the deaerator 6. In the steam generator 7, it is heated by high-temperature molten salt, thereby generating superheated steam at 1.0MPa / 230℃.

[0032] The nuclear power peak-shaving molten salt thermal storage steam supply device of the present invention enables peak-shaving operation of nuclear power. During off-peak electricity periods, electricity is connected to the molten salt thermal storage system to heat the low-temperature molten salt, thereby absorbing excess electrical energy without excessively reducing the unit output. This improves energy utilization efficiency while reducing unnecessary losses to various thermal equipment in the nuclear power unit caused by changes in operating conditions. The nuclear power peak-shaving molten salt thermal energy storage steam supply device of the present invention can achieve thermoelectric decoupling, converting excess electrical energy into energy for storage and reuse, thereby improving economic efficiency. At the same time, molten salt thermal energy storage technology has a high degree of maturity and does not require excessively high costs or restrictive construction conditions. The integrated system of nuclear power thermal energy storage further increases the dispatchability of the power grid, laying the foundation for the large-scale participation of nuclear power in grid peak shaving.

[0033] Specifically, the low-temperature demineralized water must be at least 20°C higher than the melting point of the molten salt before entering the steam generator 7 to ensure that the molten salt does not solidify during heat exchange, thus guaranteeing the safety of the molten salt thermal storage system during heat release operation. However, since the feedwater is at room temperature (15°C), direct heat exchange between the high-temperature molten salt and the low-temperature feedwater may cause the molten salt to solidify, posing a risk of freezing and blockage.

[0034] The water inlet pipe 8 includes a first branch 10 and a second branch 11. The deaerator 6 is located on the first branch 10, and the water preheater 2 is located on the second branch 11. One end of the second branch 11 is connected to the steam generator 7.

[0035] Meanwhile, a return water pipe 12 is provided between the steam generator 7 and the deaerator 6, and a steam pipeline 17 is provided at the outlet of the steam generator 7. A regulating valve 16 is provided on the return water pipe 12 and the steam pipeline 17 to regulate the flow rate of hot steam entering the deaerator 6 and the flow rate of hot steam discharged.

[0036] The nuclear power peak-shaving molten salt thermal storage and steam supply device also includes a booster pipeline 13, which is used to connect the deaerator 6 and the second branch 11. A feedwater booster pump 14 is provided on the booster pipeline 13.

[0037] Superheated steam at 1.0 MPa / 230℃, drawn at a flow rate of 10 t / h, will be partially introduced into deaerator 6 to heat and deoxygenate the feedwater, raising it to 175℃. The heated feedwater will then be pumped into the steam generation system via feedwater booster pump 14. The heat stored in the molten salt will be transferred to the feedwater to generate superheated steam for external supply. During initial system startup, feedwater preheater 2 will also be activated to heat the feedwater to 175℃.

[0038] Since the steam supply pressure is 1.0 MPa and the saturation temperature is 184℃, and the temperature rise is from 175℃ to 230℃, the feedwater preheater 2 can be omitted, and a true steam generator 7 can be used directly.

[0039] The demineralized water at ambient temperature enters the deaerator 6 for heating and deoxygenation, is then pressurized by the feedwater pump and heated in the feedwater heater, before entering the steam generator 7. There, it exchanges heat with steam / high-temperature molten salt to generate superheated steam. Except for the deaerator 6, all the heat exchangers mentioned above are shell-and-tube heat exchangers.

[0040] Specifically, the heat storage medium in the cold molten salt storage tank 3 and the hot molten salt storage tank 5 is a low-melting-point binary molten salt.

[0041] The molten salt thermal storage system also includes a waste heat recovery mechanism 15, which is connected in parallel to the connecting pipeline between the cold molten salt storage tank 3 and the hot molten salt storage tank 5, thereby recovering waste heat and increasing the utilization of waste heat.

[0042] The nuclear power peak-shaving molten salt thermal storage and steam supply device also includes a regulating valve 16, which is located on the water inlet pipe 8, the connecting pipe, the connecting pipe between the cold molten salt storage tank 3 and the hot molten salt storage tank 5, thereby regulating the flow rate of the liquid.

[0043] In this embodiment, the water supply delivery structure 1 is a water supply pump.

[0044] The present invention also provides a nuclear power peak-shaving molten salt thermal storage steam supply system, including the aforementioned nuclear power peak-shaving molten salt thermal storage steam supply device.

[0045] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A nuclear power peak-shaving molten salt heat storage steam supply device, characterized in that, The device comprises a feedwater preheating system, a molten salt heat storage system and a steam generation system, the feedwater preheating system comprises a feedwater conveying structure (1) and a feedwater preheater (2), the molten salt heat storage system comprises a cold molten salt storage tank (3), a molten salt electric heater (4) and a hot molten salt storage tank (5) connected in sequence, the steam generation system comprises a deaerator (6) and a steam generator (7), the feedwater conveying structure (1) and the feedwater preheater (2) are arranged on a water inlet pipe (8), the feedwater conveying structure (1) is connected with the deaerator (6), the feedwater preheater (2) is connected with the steam generator (7), the steam generator (7) is connected with the deaerator (6), and the steam generator (7) is connected in series on a heat conveying pipeline (9) of the cold molten salt storage tank (3) and the hot molten salt storage tank (5). The water inlet pipe (8) comprises a first branch (10) and a second branch (11), the deaerator (6) is arranged on the first branch (10), and the feedwater preheater (2) is arranged on the second branch (11), one end of the second branch (11) is connected with the steam generator (7).

2. The nuclear power peak-shaving molten salt thermal storage steam supply device according to claim 1, characterized in that, A backwater pipe (12) is arranged between the steam generator (7) and the deaerator (6).

3. The nuclear power peak-shaving molten salt thermal storage steam supply device of claim 2, wherein, A booster pipeline (13) is further arranged, and the booster pipeline (13) is used for connecting the deaerator (6) and the second branch (11).

4. The nuclear power peak-shaving molten salt thermal storage steam supply apparatus of any one of claims 1-3, wherein, A feedwater booster pump (14) is arranged on the booster pipeline (13).

5. The nuclear power peak-shaving molten salt thermal storage steam generator of claim 4, wherein, The heat storage medium in the cold molten salt storage tank (3) and the hot molten salt storage tank (5) is a low-melting-point binary molten salt.

6. The nuclear power peak-shaving molten salt thermal storage steam generator of claim 4, wherein, The molten salt heat storage system further comprises a waste heat recovery mechanism (15), and the waste heat recovery mechanism (15) is connected in parallel on a connecting pipeline of the cold molten salt storage tank (3) and the hot molten salt storage tank (5).

7. The nuclear power peak-shaving molten salt thermal storage steam generator of claim 5, wherein, An adjusting valve (16) is further arranged on the water inlet pipe (8), the backwater pipe (12) and the connecting pipeline.

8. The nuclear power peak-shaving molten salt thermal storage steam generator of claim 6, wherein, The feedwater conveying structure (1) is a feedwater pump.

9. The nuclear power peak-shaving molten salt thermal storage steam generator of claim 1, wherein, The device comprises the molten salt heat storage steam generation device for nuclear power peak shaving according to any one of claims 1-9.

10. A nuclear power peak-shaving molten salt thermal storage steam supply system, characterized in that, The device comprises the molten salt heat storage steam generation device for nuclear power peak shaving according to any one of claims 1-9.

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