High-temperature heat storage power generation system and operation method

Abstract

The invention discloses a high-temperature heat storage power generation system and an operation method, relates to the technical field of new energy power consumption, and aims to solve the problems of low energy release process efficiency and limited energy release power when renewable power is consumed through a heat storage system in the prior art. The system comprises a fused salt side circulation loop and a steam side loop communicated with the fused salt side circulation loop. The fused salt side circulation loop is provided with a high-temperature fused salt tank and a low-temperature fused salt tank, and a fused salt electric heating device is arranged and connected between the high-temperature fused salt tank and the low-temperature fused salt tank; the steam side loop comprises a superheater and a steam turbine set connected with the superheater, and the steam turbine set is further sequentially connected with a preheater and an evaporator. The electric heating device is driven by new energy electric power, heat is stored at a higher temperature, high-temperature and high-pressure high-grade steam can be generated during energy release to drive the turboset to generate power, and the system has the advantages of being large in energy release power and high in energy conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy power consumption, and in particular to a high-temperature heat storage power generation system and an operation method thereof. Background Art

[0002] New energy will gradually become the main energy source in my country's energy system. In the process of energy structure transformation and upgrading, on the one hand, the high proportion of new energy will have an impact on the stable operation of the power grid, and on the other hand, some traditional coal-fired power will face the situation of retirement or closure. How to solve the problem of energy consumption under the high proportion of renewable energy in the future will be a major problem.

[0003] The Chinese patent with publication number CN116031913A discloses a wind power storage system based on Carnot battery energy storage technology. When storing energy, a heat pump is used to convert new energy electricity into heat and store it in a phase change heat storage material. When releasing energy, the heat energy drives the organic Rankine cycle to generate electricity. However, this technical solution is limited by the low heat storage temperature range of the phase change heat storage material, and there are problems such as insufficient work capacity and low efficiency of the organic Rankine cycle. Summary of the invention

[0004] The present invention solves the problems of low energy release efficiency and limited energy release power in the prior art solutions when consuming renewable electricity through a heat storage system, and proposes a high-temperature heat storage power generation system and an operation method, introducing sodium hydroxide molten salt as a heat storage medium, and using new energy electricity to drive an electric heating device to store heat at a higher temperature. When releasing energy, high-temperature and high-pressure high-grade steam can be generated to drive a steam turbine unit to generate electricity. The system has the advantages of large energy release power and high energy conversion efficiency.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a high-temperature heat storage power generation system, comprising a molten salt side circulation loop and a steam side loop connected to the molten salt side circulation loop; the molten salt side circulation loop is provided with a high-temperature molten salt tank and a low-temperature molten salt tank, and a molten salt electric heating device is arranged and connected between the high-temperature molten salt tank and the low-temperature molten salt tank; the steam side loop comprises a superheater and a steam turbine unit connected to the superheater, and the steam turbine unit is also connected in sequence with a preheater and an evaporator.

[0006] In this technical solution, when the system is storing energy, renewable energy drives the molten salt electric heating device to convert abandoned wind and solar power into higher-quality thermal energy. In the energy release stage, high-temperature and high-pressure high-quality steam is directly generated to drive the retired steam turbine unit to achieve efficient power generation. The entire system has the technical advantages of higher efficiency, flexible and controllable power generation, and low cost.

[0007] The present invention is further configured as follows: the outlet of the high-temperature molten salt tank is connected to a first molten salt pump, the outlet of the first molten salt pump is sequentially connected to a superheater, an evaporator and a preheater, the preheater is connected to a low-temperature molten salt tank, the outlet of the low-temperature molten salt tank is connected to a second molten salt pump, and the second molten salt pump is sequentially connected to a molten salt electric heating device and a high-temperature molten salt tank.

[0008] In this technical solution, a first molten salt pump is provided at the outlet of the high-temperature molten salt tank, and a second molten salt pump is provided at the outlet of the low-temperature molten salt tank. Renewable electricity can drive the molten salt electric heating device to heat the low-temperature molten salt, and the temperature is greatly increased when it enters the high-temperature molten salt tank, thereby realizing the consumption of renewable electricity.

[0009] The present invention is further configured such that both the high-temperature molten salt tank and the low-temperature molten salt tank use sodium hydroxide molten salt as the heat storage medium.

[0010] In this technical solution, the introduction of sodium hydroxide molten salt as a heat storage medium can significantly increase the operating temperature of the heat storage system.

[0011] The present invention is further configured such that: the outlet of the first molten salt pump is also connected to a reheater, and the outlet of the reheater is connected to a superheater.

[0012] The present invention is further configured as follows: a tempering molten salt tank is provided at the outlet of the high-temperature molten salt tank, and the tempering molten salt tank is connected to the outlet of the high-temperature molten salt tank through a regulating valve.

[0013] In this technical solution, the corrosion problem of hydroxide salts on metals is solved by setting up corresponding tempering molten salt tanks and corresponding molten salt tempering processes, which can ensure the stable and safe operation of the system.

[0014] The present invention is further configured as follows: the tempering molten salt tank uses a molybdate-phosphate mixed molten salt, and the ratio of the molybdate to the phosphate is 1:5-1:10.

[0015] In the present technical solution, the corrosion problem of hydroxide salt on metal is solved by setting up the above-mentioned tempering molten salt tank and corresponding materials and adopting the corresponding molten salt tempering process.

[0016] The present invention is further configured as follows: the steam turbine unit includes a high-pressure cylinder, the high-pressure cylinder is connected to a medium-pressure cylinder, the medium-pressure cylinder is connected to a low-pressure cylinder, the low-pressure cylinder is connected to a condenser, and the condenser outlet is connected to a condensate pump.

[0017] The present invention is further configured as follows: the condensate pump is sequentially connected to a low-pressure heater and a deaerator, and the other end of the deaerator is sequentially connected to a feed water pump and a high pressure heater.

[0018] In the present technical solution, the above-mentioned steam turbine unit can operate in the energy release stage.

[0019] The present invention is further configured such that the inner walls of the high-temperature molten salt tank and the low-temperature molten salt tank are both welded with aluminum alloy.

[0020] In the technical solution, further anti-corrosion protection is performed by welding corresponding aluminum alloy on the inner wall.

[0021] A method for operating a high-temperature heat storage power generation system is applicable to the above-mentioned high-temperature heat storage power generation system, comprising the following steps: S1, use a tempered molten salt tank to perform anti-corrosion treatment on the system, so that an anti-corrosion passivation film is formed inside the molten salt circuit; S2, using renewable electricity to drive a molten salt electric heating device to heat the low-temperature molten salt and heat it into a high-temperature molten salt tank; S3, generates high-temperature and high-pressure steam and then drives the steam turbine unit to generate electricity.

[0022] In this technical solution, the above-mentioned high-temperature heat storage power generation system is first subjected to anti-corrosion treatment. After the anti-corrosion treatment is completed, the system sequentially performs heat storage and energy release for power generation. The molten salt electric heating device is driven by renewable electricity to heat the low-temperature molten salt. The low-temperature molten salt enters the high-temperature molten salt tank after the temperature of the molten salt electric heating device is increased from 330°C to 700°C, thereby realizing the consumption of renewable electricity. The high-temperature molten salt flows through the superheater, evaporator and preheater in sequence through the first molten salt pump, and enters the low-temperature molten salt tank after heat release. A stream of the high-temperature molten salt flows through the reheater and returns to the superheater outlet. After the feed water passes through the high-pressure heating, it flows through the preheater, evaporator and superheater in sequence to exchange heat with the high-temperature molten salt to generate high-temperature and high-pressure steam. The steam enters the high-pressure cylinder to do work and then returns to the reheater to exchange heat with the molten salt to heat up again, and then enters the medium-pressure cylinder and the low-pressure cylinder to do work and generate electricity, thereby realizing the thermoelectric conversion of the high-temperature heat storage system.

[0023] The present invention can bring the following beneficial effects: 1. The present invention relates to a high-temperature heat storage power generation system, which uses sodium hydroxide molten salt as the heat storage medium, improves the operating temperature range of the existing molten salt heat storage system (330°C~700°C), converts green electricity into higher-grade heat for storage, and realizes a large-scale consumption of green electricity; 2. A high-temperature heat storage power generation system of the present invention directly generates high-temperature and high-pressure main steam to drive the steam turbine unit to generate electricity during the energy release process, which significantly improves the overall efficiency of the system and the upper limit of the energy release power, while saving the cost of the entire system; 3. The present invention also adopts a tempered molten salt tank and a corresponding molten salt tempering and anti-corrosion process, and forms a metal anti-corrosion passivation film by pre-treating the inner wall of the molten salt circulation loop; during the operation, the tempered molten salt is added to the sodium hydroxide molten salt, which greatly slows down the corrosion effect of the sodium hydroxide molten salt on the metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an overall schematic diagram of a high-temperature heat storage power generation system of the present application.

[0025] Figure 2 It is a schematic internal side view of a high-temperature molten salt tank or a low-temperature molten salt tank of a high-temperature heat storage power generation system of the present application.

[0026] Figure 3 It is a schematic top view of the interior of a high-temperature molten salt tank or a low-temperature molten salt tank of a high-temperature heat storage power generation system of the present application.

[0027] Reference numerals: 1. High-pressure molten salt tank 2. Tempering molten salt tank 3. Molten salt electric heating device 4. Low-salt molten salt tank 5. Preheater 6. Evaporator 7. Superheater 8. Reheater 9. High-pressure cylinder 10. Medium-pressure cylinder 11. Low-pressure cylinder 12. Condenser 13. Condensate pump 14. Low-pressure heater 15. Deaerator 16. Feedwater pump 17. High-pressure heater 18. Generator 101. Side wall anodized aluminum block 102. Bottom wall anodized aluminum block 103. Inner bottom plate. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation method described herein is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Existing technical solutions for absorbing renewable electricity through heat storage systems are often limited by the working temperature of the heat storage medium. Most of the energy release methods are to generate electricity through organic Rankine cycle or produce medium and low pressure steam to drive steam turbines for power generation. There are problems of low efficiency of the energy release process and limited energy release power.

[0030] Example 1 In view of the above technical problems, this embodiment proposes a high temperature heat storage power generation system, referring to Figure 1 It mainly includes a molten salt side circulation loop and a steam side loop. The steam side loop is connected to the molten salt side circulation loop. The molten salt side circulation loop is provided with corresponding high-temperature molten salt tank 1 and low-temperature molten salt tank 4. More specifically, a molten salt electric heating device 3 is provided between the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4. The molten salt electric heating device 3 is respectively connected to the above-mentioned high-temperature molten salt tank 1 and low-temperature molten salt tank 4. The steam side loop mainly includes a superheater 7, a steam turbine unit, a preheater 5 and an evaporator 6. The superheater 7 is connected to the steam turbine unit, and the steam turbine unit is also connected to the preheater 5 and the evaporator 6 in sequence.

[0031] In the above technical solution, when the system is storing energy, renewable energy drives the molten salt electric heating device 3 to convert abandoned wind and solar power into higher-quality thermal energy, and directly generates high-temperature and high-pressure high-quality steam to drive the retired steam turbine unit in the energy release stage to achieve efficient power generation. The entire system has the technical advantages of higher efficiency, flexible and controllable power generation, and low cost.

[0032] Further, the outlet of the high-temperature molten salt tank 1 is connected to the first molten salt pump, which is a high-temperature molten salt pump, and the outlet of the first molten salt pump is connected to the superheater 7, and the other end of the superheater 7 is connected to the evaporator 6 and the preheater 5 in sequence, and the other end of the preheater 5 is also connected to the low-temperature molten salt tank 4, and the outlet of the low-temperature molten salt tank 4 is connected to the second molten salt pump, which is a low-temperature molten salt pump, and the outlet of the second molten salt pump is connected to the molten salt electric heating device 3, and the other end of the molten salt electric heating device 3 is connected to the high-temperature molten salt tank 1. The molten salt electric heating device 3 is driven by new energy electricity; in this embodiment, the molten salt electric heating device 3 is specifically a molten salt electric heater.

[0033] In the above technical solution, a first molten salt pump is provided at the outlet of the high-temperature molten salt tank 1, and a second molten salt pump is provided at the outlet of the low-temperature molten salt tank 4. Renewable electricity can drive the molten salt electric heating device 3 to heat the low-temperature molten salt, and the temperature is greatly increased when entering the high-temperature molten salt tank 1, thereby realizing the consumption of renewable electricity.

[0034] In more detail, the high temperature molten salt tank 1 and the low temperature molten salt tank 4 both use sodium hydroxide molten salt as the heat storage medium. In this technical solution, the introduction of sodium hydroxide molten salt as the heat storage medium can significantly increase the operating temperature of the heat storage system.

[0035] In addition, a corresponding reheater 8 is connected to the outlet of the first molten salt pump, one end of the reheater 8 is connected to the outlet of the first molten salt pump, and the other end of the reheater 8 is connected to the superheater 7 .

[0036] On the basis of the above technical solution, a tempering molten salt tank 2 is provided at the outlet of the high-temperature molten salt tank 1, and the tempering molten salt tank 2 can be connected to the high-temperature molten salt tank 1. Specifically, the tempering molten salt tank 2 can be connected to the outlet of the high-temperature molten salt tank 1 through a regulating valve connected thereto.

[0037] In the above technical solution, the corrosion problem of hydroxide salt on metal is solved by setting a corresponding tempering molten salt tank 2 and a corresponding molten salt tempering process, which can ensure the stable and safe operation of the system.

[0038] More specifically, the tempering molten salt tank 2 uses a molybdate-phosphate mixed molten salt, and the ratio of molybdate to phosphate is 1:5-1:10. Of course, the above ratio of molybdate to phosphate is only the optimal ratio preferred in this embodiment, and its implementation is not limited to the above optimal ratio.

[0039] Continue to refer Figure 1 The steam turbine unit includes a high-pressure cylinder 9, an intermediate-pressure cylinder 10, a low-pressure cylinder 11, a condenser 12, a condensate pump 13, a low-pressure heater 14, a deaerator 15, a feed water pump 16 and a high-pressure cylinder 17.

[0040] The high-pressure cylinder 9 can be connected to the superheater 7 and the reheater 8 respectively, the other end of the high-pressure cylinder 9 is connected to the medium-pressure cylinder 10, the other end of the medium-pressure cylinder 10 is connected to the low-pressure cylinder 11, the other end of the low-pressure cylinder 11 is connected to the condenser 12, the other end of the condenser 12 is connected to the condensate pump 13, the other end of the condensate pump 13 is connected to the low-pressure heater 14, the other end of the low-pressure heater 14 is connected to the deaerator 15, the other end of the deaerator 15 is connected to the feed water pump 16, and the other end of the feed water pump 16 is connected to the high-pressure 17. One end of the low-pressure cylinder 11 is also connected to the generator 18. The above-mentioned steam turbine unit can operate in the energy release stage.

[0041] In addition, aluminum alloy is provided on the inner walls of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 , and the aluminum alloy is connected to the inner wall of the high-temperature molten salt tank 1 or the low-temperature molten salt tank 4 by welding.

[0042] In the above technical solution, anti-corrosion protection is further performed by welding corresponding aluminum alloy on the inner wall.

[0043] This embodiment also proposes an operation method of a high-temperature heat storage power generation system, which mainly includes the following steps.

[0044] Step S1, using a tempering molten salt tank and a corresponding molten salt tempering process to perform anti-corrosion treatment on the system, so that a corresponding anti-corrosion passivation film is formed inside the molten salt loop.

[0045] Step S2, after the anti-corrosion treatment is completed, the low-temperature molten salt is heated by using a molten salt electric heating device driven by renewable electricity, and enters the high-temperature molten salt tank after the temperature is raised.

[0046] Step S3, after completing step S2, high-temperature and high-pressure steam is generated to drive the steam turbine unit to generate electricity.

[0047] In the above technical scheme, the above high temperature heat storage power generation system is firstly subjected to anti-corrosion treatment. After the anti-corrosion treatment is completed, the system sequentially performs heat storage and energy release for power generation. The molten salt electric heating device is driven by renewable electricity to heat the low temperature molten salt. The low temperature molten salt enters the high temperature molten salt tank after the temperature is increased from 330°C to 700°C by the molten salt electric heating device, so as to realize the consumption of renewable electricity. The high temperature molten salt flows through the superheater, evaporator and preheater in turn through the first molten salt pump, and enters the low temperature molten salt tank after heat release. A stream of the high temperature molten salt flows through the reheater and returns to the superheater outlet. After the feed water passes through the high pressure heating, it flows through the preheater, evaporator and superheater in turn to exchange heat with the high temperature molten salt to generate high temperature and high pressure steam. The steam enters the high pressure cylinder to do work and then returns to the reheater to exchange heat with the molten salt to heat up again, and then enters the medium pressure cylinder and the low pressure cylinder to do work and generate electricity, so as to realize the thermoelectric conversion of the high temperature heat storage system.

[0048] This technical solution introduces sodium hydroxide molten salt as a heat storage medium to increase the operating temperature of the heat storage system. During energy storage, renewable energy drives the electric heating device to convert abandoned wind and solar power into higher-grade thermal energy. During the energy release stage, high-temperature and high-pressure high-grade steam is directly generated to drive the steam turbine unit to achieve efficient power generation. The corresponding molten salt tempering process is used to solve the problem of hydroxide salt corrosion on metals and ensure the stable and safe operation of the system. The entire system has the technical advantages of higher efficiency, flexible and controllable power generation, and low investment cost.

[0049] Example 2 A high-temperature heat storage power generation system of the present embodiment mainly includes a molten salt side circulation loop and a steam side loop. The steam side loop is connected to the molten salt side circulation loop. The molten salt side circulation loop is provided with corresponding high-temperature molten salt tank 1 and low-temperature molten salt tank 4. More specifically, a molten salt electric heating device 3 is provided between the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4. The molten salt electric heating device 3 is respectively connected to the above-mentioned high-temperature molten salt tank 1 and low-temperature molten salt tank 4. The steam side loop mainly includes a superheater 7, a steam turbine unit, a preheater 5 and an evaporator 6. The superheater 7 is connected to the steam turbine unit, and the steam turbine unit is also connected to the preheater 5 and the evaporator 6 in sequence.

[0050] In the above technical solution, when the system is storing energy, renewable energy drives the molten salt electric heating device 3 to convert abandoned wind and solar power into higher-quality thermal energy, and directly generates high-temperature and high-pressure high-quality steam to drive the retired steam turbine unit in the energy release stage to achieve efficient power generation. The entire system has the technical advantages of higher efficiency, flexible and controllable power generation, and low cost.

[0051] Furthermore, the outlet of the high-temperature molten salt tank 1 is connected to the first molten salt pump, which is a high-temperature molten salt pump. The outlet of the first molten salt pump is connected to the superheater 7. The other end of the superheater 7 is connected to the evaporator 6 and the preheater 5 in sequence. The other end of the preheater 5 is also connected to the low-temperature molten salt tank 4. The outlet of the low-temperature molten salt tank 4 is connected to the second molten salt pump, which is a low-temperature molten salt pump. The outlet of the second molten salt pump is connected to the molten salt electric heating device 3. The other end of the molten salt electric heating device 3 is connected to the high-temperature molten salt tank 1.

[0052] In the above technical solution, a first molten salt pump is provided at the outlet of the high-temperature molten salt tank 1, and a second molten salt pump is provided at the outlet of the low-temperature molten salt tank 4. Renewable electricity can drive the molten salt electric heating device 3 to heat the low-temperature molten salt, and the temperature is greatly increased when entering the high-temperature molten salt tank 1, thereby realizing the consumption of renewable electricity.

[0053] In more detail, the high temperature molten salt tank 1 and the low temperature molten salt tank 4 both use sodium hydroxide molten salt as the heat storage medium. In this technical solution, the introduction of sodium hydroxide molten salt as the heat storage medium can significantly increase the operating temperature of the heat storage system.

[0054] In addition, a corresponding reheater 8 is connected to the outlet of the first molten salt pump, one end of the reheater 8 is connected to the outlet of the first molten salt pump, and the other end of the reheater 8 is connected to the superheater 7 .

[0055] On the basis of the above technical solution, a tempering molten salt tank 2 is provided at the outlet of the high-temperature molten salt tank 1, and the tempering molten salt tank 2 can be connected to the high-temperature molten salt tank 1. Specifically, the tempering molten salt tank 2 can be connected to the outlet of the high-temperature molten salt tank 1 through a regulating valve connected thereto.

[0056] In the above technical solution, the corrosion problem of hydroxide salt on metal is solved by setting a corresponding tempering molten salt tank 2 and a corresponding molten salt tempering process, which can ensure the stable and safe operation of the system.

[0057] More specifically, the tempering molten salt tank 2 uses a molybdate-phosphate mixed molten salt, and the ratio of molybdate to phosphate is 1:5-1:10. Of course, the above ratio of molybdate to phosphate is only the optimal ratio preferred in this embodiment, and its implementation is not limited to the above optimal ratio.

[0058] Continue to refer Figure 1 The steam turbine unit includes a high-pressure cylinder 9, an intermediate-pressure cylinder 10, a low-pressure cylinder 11, a condenser 12, a condensate pump 13, a low-pressure heater 14, a deaerator 15, a feed water pump 16 and a high-pressure cylinder 17.

[0059] The high-pressure cylinder 9 can be connected to the superheater 7 and the reheater 8 respectively, the other end of the high-pressure cylinder 9 is connected to the medium-pressure cylinder 10, the other end of the medium-pressure cylinder 10 is connected to the low-pressure cylinder 11, the other end of the low-pressure cylinder 11 is connected to the condenser 12, the other end of the condenser 12 is connected to the condensate pump 13, the other end of the condensate pump 13 is connected to the low-pressure heater 14, the other end of the low-pressure heater 14 is connected to the deaerator 15, the other end of the deaerator 15 is connected to the feed water pump 16, and the other end of the feed water pump 16 is connected to the high-pressure heater 17. The above-mentioned steam turbine unit can operate in the energy release stage.

[0060] In addition, aluminum alloy is provided on the inner walls of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 , and the aluminum alloy is connected to the inner wall of the high-temperature molten salt tank 1 or the low-temperature molten salt tank 4 by welding.

[0061] Based on the above-mentioned high-temperature heat storage power generation system, the process of using a tempering molten salt tank and a corresponding molten salt tempering process to perform anti-corrosion treatment on the system in this embodiment mainly includes the following steps.

[0062] Step S11, first, the system pre-treats the inner wall of the molten salt measurement loop before activation, specifically: heat and modulate the molten salt inside the molten salt tank to 650°C for salting, adjust the valve at the outlet of the high-temperature molten salt tank to allow the tempered molten salt to circulate on the molten salt side, flow through the superheater, evaporator, and preheater in turn into the low-temperature molten salt tank; flow from the outlet of the low-temperature tank into the molten salt electric heating device, and finally return to the tempered molten salt tank. During the pre-treatment process, the tempered molten salt circulates in the loop for no less than 50 times to ensure that an anti-corrosion passivation film is formed inside the molten salt loop.

[0063] Step S12, when sodium hydroxide molten salt is used for heat storage and release, it is first necessary to turn on the tempering molten salt pump, which is arranged between the tempering molten salt tank and the high-temperature molten salt tank, and the tempering molten salt pump is connected to the tempering molten salt tank and the high-temperature molten salt tank respectively. After turning on, the tempering molten salt is mixed with the sodium hydroxide molten salt in a certain proportion in the high-temperature molten salt tank and then enters the molten salt side circulation loop. In this embodiment, the amount of tempering molten salt is generally 3-5% of the amount of sodium hydroxide molten salt. Of course, in the actual implementation process, the ratio of the amount of tempering molten salt to the amount of sodium hydroxide molten salt is not limited to the above 3-5%.

[0064] Step S13, after the system runs for a period of time, the molten salt side circulation loop is regularly passivated using tempered molten salt (650°C); during the treatment process, the sodium hydroxide molten salt valve channel is closed and does not enter the circulation loop. In this embodiment, as a preferred time interval, it is 28-35 days, and of course other time intervals can also be set.

[0065] For step S2 and step S3 in embodiment 1, in more detail, they include the following process.

[0066] For step S2, when the system is storing heat, the low-temperature molten salt flows through the electric heating device via the second molten salt pump, and the renewable electricity drives the molten salt electric heating device to heat the low-temperature molten salt. The low-temperature molten salt is heated from 330°C to 700°C by the molten salt electric heating device and then enters the high-temperature molten salt tank, thereby finally absorbing renewable electricity.

[0067] For step S3, when the system releases energy to generate electricity, the high-temperature molten salt flows through the superheater, evaporator and preheater in sequence through the high-temperature molten salt pump, and enters the low-temperature molten salt tank after releasing heat; a branch of the high-temperature molten salt flows through the reheater and returns to the superheater outlet. After the high-pressure heater, the feed water flows through the preheater, evaporator and superheater in sequence to exchange heat with the high-temperature molten salt to generate high-temperature and high-pressure steam. The steam enters the high-pressure cylinder to do work and then returns to the reheater to exchange heat with the molten salt to heat up again, and then enters the medium-pressure cylinder and the low-pressure cylinder to do work and generate electricity, realizing the thermoelectric conversion of the high-temperature heat storage system.

[0068] Example 3 A high-temperature heat storage power generation system of the present embodiment mainly includes a molten salt side circulation loop and a steam side loop. The steam side loop is connected to the molten salt side circulation loop. The molten salt side circulation loop is provided with corresponding high-temperature molten salt tank 1 and low-temperature molten salt tank 4. More specifically, a molten salt electric heating device 3 is provided between the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4. The molten salt electric heating device 3 is respectively connected to the above-mentioned high-temperature molten salt tank 1 and low-temperature molten salt tank 4. The steam side loop mainly includes a superheater 7, a steam turbine unit, a preheater 5 and an evaporator 6. The superheater 7 is connected to the steam turbine unit, and the steam turbine unit is also connected to the preheater 5 and the evaporator 6 in sequence.

[0069] In the above technical solution, when the system is storing energy, renewable energy drives the molten salt electric heating device 3 to convert abandoned wind and solar power into higher-quality thermal energy, and directly generates high-temperature and high-pressure high-quality steam to drive the retired steam turbine unit in the energy release stage to achieve efficient power generation. The entire system has the technical advantages of higher efficiency, flexible and controllable power generation, and low cost.

[0070] Furthermore, the outlet of the high-temperature molten salt tank 1 is connected to the first molten salt pump, which is a high-temperature molten salt pump. The outlet of the first molten salt pump is connected to the superheater 7. The other end of the superheater 7 is connected to the evaporator 6 and the preheater 5 in sequence. The other end of the preheater 5 is also connected to the low-temperature molten salt tank 4. The outlet of the low-temperature molten salt tank 4 is connected to the second molten salt pump, which is a low-temperature molten salt pump. The outlet of the second molten salt pump is connected to the molten salt electric heating device 3. The other end of the molten salt electric heating device 3 is connected to the high-temperature molten salt tank 1.

[0071] In the above technical solution, a first molten salt pump is provided at the outlet of the high-temperature molten salt tank 1, and a second molten salt pump is provided at the outlet of the low-temperature molten salt tank 4. Renewable electricity can drive the molten salt electric heating device 3 to heat the low-temperature molten salt, and the temperature is greatly increased when entering the high-temperature molten salt tank 1, thereby realizing the consumption of renewable electricity.

[0072] In more detail, the high temperature molten salt tank 1 and the low temperature molten salt tank 4 both use sodium hydroxide molten salt as the heat storage medium. In this technical solution, the introduction of sodium hydroxide molten salt as the heat storage medium can significantly increase the operating temperature of the heat storage system.

[0073] In addition, a corresponding reheater 8 is connected to the outlet of the first molten salt pump, one end of the reheater 8 is connected to the outlet of the first molten salt pump, and the other end of the reheater 8 is connected to the superheater 7 .

[0074] On the basis of the above technical solution, a tempering molten salt tank 2 is provided at the outlet of the high-temperature molten salt tank 1, and the tempering molten salt tank 2 can be connected to the high-temperature molten salt tank 1. Specifically, the tempering molten salt tank 2 can be connected to the outlet of the high-temperature molten salt tank 1 through a regulating valve connected thereto.

[0075] In the above technical solution, the corrosion problem of hydroxide salt on metal is solved by setting a corresponding tempering molten salt tank 2 and a corresponding molten salt tempering process, which can ensure the stable and safe operation of the system.

[0076] More specifically, the tempering molten salt tank 2 uses a molybdate-phosphate mixed molten salt, and the ratio of molybdate to phosphate is 1:5-1:10. Of course, the above ratio of molybdate to phosphate is only the optimal ratio preferred in this embodiment, and its implementation is not limited to the above optimal ratio.

[0077] Continue to refer Figure 1 The steam turbine unit includes a high-pressure cylinder 9, an intermediate-pressure cylinder 10, a low-pressure cylinder 11, a condenser 12, a condensate pump 13, a low-pressure heater 14, a deaerator 15, a feed water pump 16 and a high-pressure cylinder 17.

[0078] The high-pressure cylinder 9 can be connected to the superheater 7 and the reheater 8 respectively, the other end of the high-pressure cylinder 9 is connected to the medium-pressure cylinder 10, the other end of the medium-pressure cylinder 10 is connected to the low-pressure cylinder 11, the other end of the low-pressure cylinder 11 is connected to the condenser 12, the other end of the condenser 12 is connected to the condensate pump 13, the other end of the condensate pump 13 is connected to the low-pressure heater 14, the other end of the low-pressure heater 14 is connected to the deaerator 15, the other end of the deaerator 15 is connected to the feed water pump 16, and the other end of the feed water pump 16 is connected to the high-pressure heater 17. The above-mentioned steam turbine unit can operate in the energy release stage.

[0079] In addition, aluminum alloy is provided on the inner walls of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 , and the aluminum alloy is connected to the inner wall of the high-temperature molten salt tank 1 or the low-temperature molten salt tank 4 by welding.

[0080] Different from Example 1, reference Figure 2 and Figure 3 In this embodiment, side wall anode aluminum blocks 101 are arranged on the inner side walls of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 , and bottom wall anode aluminum blocks 102 are arranged on the inner bottom plates 103 of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 .

[0081] Specifically, the above-mentioned side wall anode aluminum block 101 and bottom wall anode aluminum block 102 can be connected to the inner walls of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4 by welding.

[0082] refer to Figure 2 and Figure 3 The side wall anodized aluminum blocks 101 are evenly arranged on the inner side walls of the high temperature molten salt tank 1 and the low temperature molten salt tank 4, and the bottom wall anodized aluminum blocks 102 are evenly arranged on the inner bottom plates 103 of the high temperature molten salt tank 1 and the low temperature molten salt tank 4. The bottom wall anodized aluminum blocks 102 are distributed in a circular shape, and the distances between any adjacent bottom wall anodized aluminum blocks 102 on the same circumference are the same. The above arrangement can better achieve the anti-corrosion protection effect.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A high temperature heat storage power generation system, characterized in that: The invention comprises a molten salt side circulation loop and a steam side circulation loop connected to the molten salt side circulation loop; the molten salt side circulation loop is provided with a high-temperature molten salt tank (1) and a low-temperature molten salt tank (4), and a molten salt electric heating device (3) is provided between and connected to the high-temperature molten salt tank (1) and the low-temperature molten salt tank (4); the steam side circulation loop comprises a superheater (7) and a steam turbine unit connected to the superheater (7), and the steam turbine unit is also connected in sequence to a preheater (5) and an evaporator (6).

2. A high temperature heat storage power generation system according to claim 1, characterized in that: The outlet of the high-temperature molten salt tank (1) is connected to a first molten salt pump, the outlet of the first molten salt pump is sequentially connected to a superheater (7), an evaporator (6) and a preheater (5), the preheater (5) is connected to a low-temperature molten salt tank (4), the outlet of the low-temperature molten salt tank (4) is connected to a second molten salt pump, and the second molten salt pump is sequentially connected to a molten salt electric heating device (3) and a high-temperature molten salt tank (1).

3. A high temperature heat storage power generation system according to claim 1 or 2, characterized in that: The high-temperature molten salt tank (1) and the low-temperature molten salt tank (4) both use sodium hydroxide molten salt as a heat storage medium.

4. A high temperature thermal storage power generation system according to claim 2, characterized in that: The outlet of the first molten salt pump is also connected to a reheater (8), and the outlet of the reheater (8) is connected to the superheater (7).

5. A high temperature heat storage power generation system according to claim 1 or 2, characterized in that: A tempering molten salt tank (2) is provided at the outlet of the high-temperature molten salt tank (1), and the tempering molten salt tank (2) is connected to the outlet of the high-temperature molten salt tank (1) via a regulating valve.

6. A high temperature thermal storage power generation system according to claim 5, characterized in that: The tempering molten salt tank (2) uses a molybdate-phosphate mixed molten salt, and the ratio of the molybdate to the phosphate is 1:5-1:

10.

7. A high temperature heat storage power generation system according to claim 1 or 2, characterized in that: The steam turbine unit comprises a high-pressure cylinder (9), the high-pressure cylinder (9) is connected to a medium-pressure cylinder (10), the medium-pressure cylinder (10) is connected to a low-pressure cylinder (11), the low-pressure cylinder (11) is connected to a condenser (12), and the outlet of the condenser (12) is connected to a condensate pump (13).

8. A high temperature thermal storage power generation system according to claim 7, characterized in that: The condensate pump (13) is sequentially connected to a low-pressure heater (14) and a deaerator (15), and the other end of the deaerator (15) is sequentially connected to a feed water pump (16) and a high-pressure heater (17).

9. A high temperature heat storage power generation system according to claim 1 or 2, characterized in that: The inner walls of the high-temperature molten salt tank (1) and the low-temperature molten salt tank (4) are both welded with aluminum alloy.

10. An operating method of a high-temperature heat storage power generation system, applicable to a high-temperature heat storage power generation system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, use a tempered molten salt tank to perform anti-corrosion treatment on the system, so that an anti-corrosion passivation film is formed inside the molten salt circuit; S2, using renewable electricity to drive a molten salt electric heating device to heat the low-temperature molten salt and heat it into a high-temperature molten salt tank; S3, generates high-temperature and high-pressure steam and then drives the steam turbine unit to generate electricity.

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