Molten salt heat storage and release device and method

Abstract

The invention discloses a fused salt heat storage and release device and method.The fused salt heat storage and release device comprises a flue gas heating fused salt heat storage system, a fused salt storage system, a steam-water cooling fused salt system and a control system, the flue gas heating fused salt heat storage system comprises a boiler and a fused salt heat exchanger, and a main flue of the boiler is provided with a bypass flue communicating with the fused salt heat exchanger; the fused salt storage system comprises a cold salt tank and a hot salt tank, the cold salt tank is communicated with a fused salt heat exchanger, the fused salt heat exchanger is communicated with the hot salt tank, the cold salt tank is provided with a first electric heater, and the hot salt tank is provided with a second electric heater; the steam-water cooling fused salt system comprises a fused salt cooler and a water tank which are communicated with each other, the cold salt tank and the hot salt tank are communicated with the fused salt cooler, the fused salt cooler is communicated with the cold salt tank through a fused salt return pipeline, and the fused salt cooler is provided with a third electric heater. The molten salt heat storage and heat release device disclosed by the invention can be used for carrying out performance test on heat exchange, heat storage and heat release processes of molten salt, and is suitable for different types of molten salt.

Description

Technical Field

[0001] The present invention relates to the field of molten salt energy storage technology, and more specifically, to a molten salt heat storage and release device and method. Background Art

[0002] As a new form of heat storage and energy storage, molten salt heat storage technology is one of the more mainstream high-temperature heat storage technologies, with the advantages of low cost, high heat capacity and good safety. In the past decade, many large laboratories, research institutes and enterprises in various countries have been committed to the theoretical and experimental research of molten salt heat storage technology. However, most of the research focuses on the convective heat transfer characteristics of the fluid inside or outside the heat exchange tube, lacking equipment theoretical design methods and verification research, especially flue gas molten salt heat exchanger equipment and new molten salt steam-water heat exchanger. The structural optimization and processing and manufacturing of key equipment such as molten salt heat exchangers for engineering applications require in-depth research on the molten salt heat transfer mechanism and enhanced heat exchange technology. This kind of engineering principle prototype test device is very difficult to build due to the large scale of construction investment, high energy consumption in operation and large site space requirements. At present, the molten salt test devices in universities and research institutes are generally small, and can only carry out some electric heating single-tube heat exchange or sleeve heat exchange experiments. Few flue gas heat storage experiments are carried out using coal-fired flue gas.

[0003] The patent application number CN201510918131.2 discloses a molten salt heat exchange / heat storage performance test device, including a high-temperature molten salt circulation loop and a cascade cooling system (thermal oil circulation loop and cooling water circulation loop). The application uses electricity as the heat source for heating the molten salt and thermal oil as the cooling heat source. The test bench can only be used to study the heat exchange performance data of molten salt and thermal oil. On the other hand, most of the molten salt is an oxide, and thermal oil is a combustible material. If the thermal oil leaks, it is easy to cause safety risks.

[0004] The patent application number CN201820915971.2 discloses a device for measuring the heat transfer characteristics of high-temperature molten salt in a micro-channel, including a high-temperature molten salt heating pipe section, a water circulation pipe section, a test and product collection pipe section, and a data acquisition and display module. The application uses electrically heated molten salt, and the molten salt is squeezed out of the molten salt tank by filling nitrogen. The system molten salt flow is small and is only suitable for the study of heat transfer characteristics of micro-channels. Due to the size effect, the flow field inside the heat exchange is different, and the results may not be directly used for heat exchangers of engineering size.

[0005] The patent with application number CN202110034045.0 discloses a molten salt and air heat exchange performance detection device, including a high-temperature molten salt circulation loop, a cooling mechanism arranged on the high-temperature molten salt circulation loop, and a detection mechanism arranged inside the cooling mechanism. The molten salt cooling medium used in this application is air, which cannot be promoted for other media. At the same time, since room temperature air is used, it is not suitable for high melting point molten salt experiments and is prone to solidification. In addition, the device can only perform molten salt heat release experiments for heat exchange between molten salt and air.

[0006] Therefore, there is an urgent need for a molten salt heat storage and release device that can be used for various molten salt heat exchange, heat storage and heat release performance tests. Summary of the invention

[0007] In view of this, an object of the present invention is to provide a molten salt heat storage and heat release device to test the heat exchange, heat storage and heat release performance of various molten salts.

[0008] Another core of the present invention is to disclose a molten salt heat storage and heat release method.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The molten salt heat storage and heat release device comprises:

[0011] The flue gas heating molten salt heat storage system comprises a boiler and a molten salt heat exchanger. The main flue of the boiler is provided with a bypass flue, which is connected to the molten salt heat exchanger.

[0012] A molten salt storage system, the molten salt storage system comprises a cold salt tank and a hot salt tank, the cold salt tank is connected to the molten salt heat exchanger through a cold molten salt supply pipeline and a heat exchanger molten salt delivery pipeline, the molten salt heat exchanger is connected to the hot salt tank through a hot molten salt delivery pipeline, a first bypass connected in parallel with the molten salt heat exchanger is provided between the heat exchanger molten salt delivery pipeline and the hot molten salt delivery pipeline, a first bypass valve is provided on the first bypass, the cold salt tank is provided with a first electric heater, and the hot salt tank is provided with a second electric heater;

[0013] A steam-water cooling molten salt system, the steam-water cooling molten salt system comprises a molten salt cooler and a water tank, the water tank is connected to the molten salt cooler through a water supply pipeline, and a steam outlet is provided on the molten salt cooler; a hot molten salt supply pipeline is provided in the hot salt tank, and the cold molten salt supply pipeline and the hot molten salt supply pipeline are merged to form a mixed molten salt supply pipeline, the mixed molten salt supply pipeline is connected to the molten salt cooler, the molten salt cooler is connected to the cold salt tank through a molten salt return pipeline, and the molten salt cooler is provided with a third electric heater;

[0014] The control system, the flue gas heating molten salt heat storage system, the molten salt storage system and the steam-water cooling molten salt system are all connected to the control system.

[0015] Optionally, in the above-mentioned molten salt heat storage and release device, an outlet container and a first regulating valve are provided on the hot molten salt delivery pipeline, the first regulating valve is provided downstream of the outlet container, and the outlet container is connected to the hot salt tank.

[0016] Optionally, in the above-mentioned molten salt heat storage and heat release device, a first baffle is provided in the main flue of the boiler, a second baffle and a third baffle are provided in the bypass flue, the second baffle is provided at the flue gas inlet of the molten salt heat exchanger, and the third baffle is provided at the flue gas outlet of the molten salt heat exchanger;

[0017] The flue gas outlet of the molten salt heat exchanger is connected to the low-temperature economizer of the boiler.

[0018] Optionally, in the above-mentioned molten salt heat storage and heat release device, a cold salt pump is provided on the cold molten salt supply pipeline, and a first shut-off valve is provided at the outlet of the cold salt pump;

[0019] A hot salt pump is arranged on the hot molten salt supply pipeline, and a second shut-off valve is arranged at the outlet of the hot salt pump.

[0020] Optionally, in the above-mentioned molten salt heat storage and heat release device, a second bypass connected in parallel with the cold salt pump is provided on the cold molten salt supply pipeline, the second bypass is connected to the cold salt tank, and a second bypass valve is provided on the second bypass;

[0021] The hot molten salt supply pipeline is provided with a third bypass connected in parallel with the hot salt pump, the third bypass is connected to the hot salt tank, and the third bypass is provided with a third bypass valve.

[0022] Optionally, in the above-mentioned molten salt heat storage and release device, the cold molten salt supply pipeline is split to form a first cold molten salt supply pipeline and a second cold molten salt supply pipeline, the first cold molten salt supply pipeline is connected to the molten salt heat exchanger, the second cold molten salt supply pipeline is connected to the molten salt cooler, a second regulating valve is arranged on the first cold molten salt supply pipeline, and a third regulating valve is arranged on the second cold molten salt supply pipeline.

[0023] Optionally, in the above-mentioned molten salt heat storage and heat release device, the hot molten salt supply pipeline is split to form a first hot molten salt supply pipeline and a second hot molten salt supply pipeline, the first hot molten salt supply pipeline and the first cold molten salt supply pipeline are merged to form a heat exchanger molten salt delivery pipeline, the heat exchanger molten salt delivery pipeline is connected to the molten salt heat exchanger, and a fourth regulating valve is provided on the first hot molten salt supply pipeline;

[0024] The second hot molten salt supply pipeline merges with the second cold molten salt supply pipeline to form a mixed molten salt supply pipeline. A third shut-off valve is arranged on the mixed molten salt supply pipeline, and a fifth regulating valve is arranged on the second hot molten salt supply pipeline.

[0025] Optionally, in the above-mentioned molten salt heat storage and release device, the cold molten salt supply pipeline, the heat exchanger molten salt delivery pipeline, the hot molten salt delivery pipeline, the mixed molten salt supply pipeline and the molten salt return pipeline are all provided with heating belts and temperature detection elements, and the temperature detection elements are connected to the control system.

[0026] Optionally, in the above-mentioned molten salt heat storage and heat release device, a water pump, a sixth regulating valve and a fourth bypass connected in parallel with the water pump are arranged on the water supply pipeline, the sixth regulating valve is arranged downstream of the water pump, and a fourth bypass valve is arranged on the fourth bypass;

[0027] The water supply pipeline is provided with a flow detection element and a pressure detection element connected with the control system.

[0028] A molten salt heat storage and heat release method, using the above-mentioned molten salt heat storage and heat release device, comprises the following steps:

[0029] S1. Start the boiler and open the bypass flue;

[0030] When the flue gas temperature in the main flue reaches the preset temperature, the bypass flue is opened to allow the flue gas to enter the molten salt heat exchanger;

[0031] S2, heating the cold molten salt and transporting the hot molten salt to the hot salt tank;

[0032] When the flue gas temperature in the bypass flue meets the salt feeding conditions, the cold molten salt in the cold salt tank is transported to the molten salt heat exchanger, and is stored in the hot salt tank after the temperature rises, thus realizing the molten salt heat storage process;

[0033] S3, mixing molten salt to heat water and returning to the cold salt tank;

[0034] The mixed molten salt heats the water in the molten salt cooler and then returns to the cold salt tank through the molten salt return pipeline. The water turns into water vapor and is discharged through the steam outlet, thus realizing the heat release process of the molten salt.

[0035] It can be seen from the above scheme that the molten salt heat storage and heat release device disclosed in the present invention can realize the heat exchange, heat storage and heat release process of molten salt, can perform performance tests on the heat exchange, heat storage and heat release process of molten salt, can be used for flow heat transfer performance tests of flue gas and molten salt heat exchangers, can provide heat exchange performance data for various forms of principle prototypes of flue gas and molten salt heat exchange, and can provide reliable data for the performance optimization of flue gas and molten salt heat exchangers. The use of flue gas to heat molten salt reduces the intermediate process of steam-water heat storage, reduces the quality degradation during the energy transfer process, can store higher quality thermal energy, and does not require the arrangement of high-temperature and high-pressure steam-water heat exchange equipment, and has a simpler structure. The molten salt heat storage and heat release device disclosed in the embodiment of the present invention can also be used for performance tests of steam-water and molten salt heat exchangers, and can be applied to different types of molten salts, with a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a schematic structural diagram of a molten salt heat storage and heat release device disclosed in an embodiment of the present invention;

[0038] Figure 2 This is a flow chart of the molten salt heat storage and heat release method disclosed in an embodiment of the present invention.

[0039] Among them, 1. flue gas heating molten salt heat storage system, 11. boiler, 111. convection heating surface, 12. molten salt heat exchanger, 13. outlet container, 14. low-temperature economizer, 101. main flue, 102. bypass flue, 103. hot molten salt delivery pipeline, 104. first bypass, 105. first bypass valve, 106. first baffle, 107. second baffle, 108. third baffle;

[0040] 2. Molten salt storage system, 21. Cold salt tank, 22. Hot salt tank, 23. First electric heater, 24. Second electric heater, 25. Cold salt pump, 26. Hot salt pump, 27. Salt discharge tank, 201. Cold molten salt supply pipeline, 2011. First cold molten salt supply pipeline, 2012. Second cold molten salt supply pipeline, 202. Hot molten salt supply pipeline, 2021. First hot molten salt supply pipeline, 2022. Second hot molten salt supply pipeline, 203. Mixed molten salt supply pipeline Supply pipeline, 204, first shut-off valve, 205, second shut-off valve, 206, second bypass, 207, second bypass valve, 208, third bypass, 209, third bypass valve, 210, second regulating valve, 211, third regulating valve, 212, heat exchanger molten salt delivery pipeline, 213, fourth regulating valve, 214, third shut-off valve, 215, fifth regulating valve, 216, cold salt tank drain valve, 217, hot salt tank drain valve, 218, first regulating valve;

[0041] 3. Steam-water cooling molten salt system, 31. Molten salt cooler, 32. Water tank, 33. Water pump, 34. Third electric heater, 301. Water supply pipeline, 302. Molten salt return pipeline, 303. Fourth bypass, 304. Fourth bypass valve, 305. Sixth regulating valve, 306. Exhaust valve, 307. Safety valve, 308. Drain valve. DETAILED DESCRIPTION

[0042] The core of the present invention is to disclose a molten salt heat storage and heat release device to test the heat exchange, heat storage and heat release performance of various molten salts.

[0043] Another core of the present invention is to disclose a molten salt heat storage and heat release method.

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] like Figure 1 As shown, the molten salt heat storage and heat release device disclosed in the embodiment of the present invention includes a flue gas heating molten salt heat storage system 1, a molten salt storage system 2, a steam-water cooling molten salt system 3 and a control system. The flue gas heating molten salt heat storage system 1, the molten salt storage system 2 and the steam-water cooling molten salt system 3 are specifically shown in the dotted box in the figure. The three systems are interconnected and are all connected to the control system to heat the molten salt by flue gas and then store it, thereby realizing the molten salt heat exchange and heat storage process; after the molten salt stores heat, water is heated to generate steam for production use, thereby realizing the molten salt heat release process.

[0046] Among them, the flue gas heated molten salt heat storage system 1 includes a boiler 11 and a molten salt heat exchanger 12. The main flue 101 of the boiler 11 is provided with a bypass flue 102. The bypass flue 102 is connected to the molten salt heat exchanger 12 to provide flue gas to the molten salt heat exchanger 12 so as to heat the molten salt through the flue gas. The bypass flue 102 is provided with a temperature detection element, a flow detection element and a pressure detection element connected to the control system. It should be noted that the main flue 101 refers to the flue where the air preheater and the high temperature economizer of the boiler 11 are located.

[0047] The molten salt storage system 2 includes a cold salt tank 21 and a hot salt tank 22. The cold salt tank 21 is connected to the molten salt inlet of the molten salt heat exchanger 12 through a cold molten salt supply pipeline 201 and a heat exchanger molten salt delivery pipeline 212. A first bypass 104 connected in parallel with the molten salt heat exchanger 12 is provided between the heat exchanger molten salt delivery pipeline 212 and the hot molten salt delivery pipeline 103, and a first bypass valve 105 is provided on the first bypass 104. The cold salt tank 21 is provided with a first electric heater 23, and the hot salt tank 22 is provided with a second electric heater 24. The arrangement of the first electric heater 23 and the second electric heater 24 can complete the molten salting and molten salt heating operations, and can control the molten salt temperature in the cold salt tank 21 and the hot salt tank 22.

[0048] The steam-water cooling molten salt system 3 includes a molten salt cooler 31 and a water tank 32. The water tank 32 is connected to the molten salt cooler 31 through a water supply pipeline 301. A steam outlet is provided on the molten salt cooler 31. The hot salt tank 22 is provided with a hot molten salt supply pipeline 202. The cold molten salt supply pipeline 201 and the hot molten salt supply pipeline 202 merge to form a mixed molten salt supply pipeline 203. The mixed molten salt supply pipeline 203 is connected to the molten salt cooler 31. The molten salt cooler 31 is connected to the cold salt tank 21 through a molten salt return pipeline 302. The molten salt cooler 31 is provided with a third electric heater 34. The third electric heater 34 can heat water so that the temperature of the water is higher than the crystallization temperature of the molten salt to prevent the molten salt from crystallizing and ensure the normal operation of the system.

[0049] The molten salt heat storage process is as follows: first, the boiler 11 is started. When the flue gas temperature in the main flue 101 reaches a preset temperature, the bypass flue 102 is opened to allow the flue gas to enter the molten salt heat exchanger. When the flue gas temperature meets the salt entry condition, the cold molten salt in the cold salt tank 21 is transported to the molten salt heat exchanger 12 through the cold molten salt supply pipeline 201, and heat is exchanged with the flue gas from the bypass flue 102. The temperature rises and becomes hot molten salt. The hot molten salt is transported to the hot salt tank 22 through the hot molten salt delivery pipeline 103 for storage.

[0050] The specific heat release process of the molten salt is as follows: the cold molten salt in the cold salt tank 21 and the hot molten salt in the hot salt tank 22 are mixed and enter the molten salt cooler 31 through the mixed molten salt supply pipeline 203, and the water from the water tank 32 is heated in the molten salt cooler 31 to generate steam output for production use. The molten salt after cooling is returned to the cold salt tank 21 through the molten salt return pipeline 302.

[0051] The molten salt heat storage and heat release device disclosed in the embodiment of the present invention can realize the heat exchange, heat storage and heat release process of molten salt, can perform performance tests on the heat exchange, heat storage and heat release process of molten salt, can be used for flow heat transfer performance tests of flue gas and molten salt heat exchanger 12, can provide heat exchange performance data for various forms of principle prototypes of flue gas and molten salt heat exchange, and can provide reliable data for performance optimization of flue gas and molten salt heat exchanger. The use of flue gas to heat molten salt reduces the intermediate process of steam-water heat storage, reduces the quality degradation during the energy transfer process, can store higher quality thermal energy, and does not require the arrangement of high-temperature and high-pressure steam-water heat exchange equipment, and has a simpler structure. The molten salt heat storage and heat release device disclosed in the embodiment of the present invention can also be used for performance tests of steam-water and molten salt heat exchanger 12, and can be applied to different types of molten salts, with a wide range of applications.

[0052] Furthermore, the flue gas heated molten salt heat storage system 1 includes an outlet container 13 and a first regulating valve 218 arranged on the hot molten salt delivery pipeline 103. The first regulating valve 218 is arranged downstream of the outlet container 13. An overflow pipe is arranged on the outlet container 13, and the overflow pipe is connected to the hot salt tank 22. The outlet container 13 is provided with a liquid level sensor connected to the control system.

[0053] In the molten salt heat storage process, when the inlet flue gas temperature of the bypass flue 102 meets the salt feeding condition, the opening of the first regulating valve 218 is reduced so that the flue gas molten salt heat exchanger 12 is gradually filled with molten salt. When the outlet container 13 has a certain liquid level, the first bypass valve 105 is closed, and the opening of the first regulating valve 218 is adjusted to keep the liquid level of the outlet container 13 stable. The setting of the outlet container 13 can observe whether the opening of the first regulating valve 218 is appropriate, reduce the gas contained in the hot molten salt delivery pipeline 103, and reduce the occurrence of vibration.

[0054] Furthermore, in order to adjust the flue gas flow entering the molten salt heat exchanger 12, a first baffle 106 is provided in the main flue 101, and a second baffle 107 and a third baffle 108 are provided in the bypass flue 102. The second baffle 107 is provided at the flue gas inlet of the molten salt heat exchanger 12, and the third baffle 108 is provided at the flue gas outlet of the molten salt heat exchanger 12. The flue gas outlet of the molten salt heat exchanger 12 is connected to the low-temperature economizer 14 of the boiler 11. That is, the flue gas in the main flue 101 flows into the bypass flue 102, enters the molten salt heat exchanger 12 to heat the molten salt, and then flows back to the low-temperature economizer 14 to heat the boiler feed water in the low-temperature economizer 14.

[0055] The molten salt storage system 2 includes a cold salt tank 21, a hot salt tank 22, a cold salt pump 25, a hot salt pump 26 and a salt discharge tank 27. The cold salt tank 21 and the hot salt tank 22 are both connected to the salt discharge tank 27, and a cold salt tank drain valve 216 and a hot salt tank drain valve 217 are respectively provided on the connecting pipeline. The cold salt tank 21 and the hot salt tank 22 are both provided with a liquid level sensor connected to the control system and a drain pipe connected to the salt discharge tank 27.

[0056] Specifically, the inlet of the cold salt pump 25 is connected to the cold salt tank 21, and the outlet of the cold salt pump 25 is connected to the molten salt heat exchanger 12 and the molten salt cooler 31. The inlet of the hot salt pump 26 is connected to the hot salt tank 22, and the outlet of the hot salt pump 26 is connected to the molten salt heat exchanger 12 and the molten salt cooler 31. The cold salt pump 25 and the hot salt pump 26 provide power for conveying cold molten salt and hot molten salt, preferably a variable frequency pump. A first shut-off valve 204 is provided at the outlet of the cold salt pump 25, and a second shut-off valve 205 is provided at the outlet of the hot salt pump 26. Preferably, the cold salt pump 25, the hot salt pump 26, the first shut-off valve 204 and the second shut-off valve 205 are all connected to the control system.

[0057] In order to adjust the flow and pressure conditions of cold molten salt and hot molten salt, a second bypass 206 connected in parallel with the cold salt pump 25 is provided on the cold molten salt supply pipeline 201, the second bypass 206 is connected to the cold salt tank 21, and a second bypass valve 207 is provided on the second bypass 206. A third bypass 208 connected in parallel with the hot salt pump 26 is provided on the hot molten salt supply pipeline 202, the third bypass 208 is connected to the hot salt tank 22, and a third bypass valve 209 is provided on the third bypass 208. The setting of the second bypass 206 and the third bypass 208 can establish the minimum flow of the cold salt pump 25 and the hot salt pump 26, and cooperate with the cold salt pump 25 and the hot salt pump 26 to realize the wide range of adjustable molten salt flow, and can be used for pressure relief during the inspection and maintenance of the cold salt pump 25 and the hot salt pump 26. The second bypass valve 207 and the third bypass valve 209 are preferably electric valves connected to the control system.

[0058] Furthermore, the cold salt tank 21 is connected to the molten salt heat exchanger 12 and the molten salt cooler 31 respectively, which can be achieved by a split tee, specifically, as Figure 1 As shown, the cold molten salt supply pipeline 201 is split to form a first cold molten salt supply pipeline 2011 and a second cold molten salt supply pipeline 2012, the first cold molten salt supply pipeline 2011 is connected to the molten salt heat exchanger 12, the second cold molten salt supply pipeline 2012 is connected to the molten salt cooler 31, the first cold molten salt supply pipeline 2011 is provided with a second regulating valve 210, and the second cold molten salt supply pipeline 2012 is provided with a third regulating valve 211, preferably, the second regulating valve 210 and the third regulating valve 211 are both connected to the control system, and of course, the above two valves can also use manual regulating valves. The above two valves can respectively adjust the flow of cold molten salt entering the first cold molten salt supply pipeline 2011 and the second cold molten salt supply pipeline 2012.

[0059] The hot salt tank 22 is connected to the molten salt heat exchanger 12 and the molten salt cooler 31 respectively, which can be realized by a diversion tee. Specifically, the hot molten salt supply pipeline 202 is diverted to form a first hot molten salt supply pipeline 2021 and a second hot molten salt supply pipeline 2022. The first hot molten salt supply pipeline 2021 and the first cold molten salt supply pipeline 2011 are merged to form a heat exchanger molten salt delivery pipeline 212. The heat exchanger molten salt delivery pipeline 212 is connected to the molten salt heat exchanger 12. The first hot molten salt supply pipeline 2021 is provided with a fourth regulating valve 213. The second hot molten salt supply pipeline 2022 and the second cold molten salt supply pipeline 2012 are merged to form a mixed molten salt supply pipeline 203. The mixed molten salt supply pipeline 203 is provided with a third shut-off valve 214, and the second hot molten salt supply pipeline 2022 is provided with a fifth regulating valve 215. The fourth regulating valve 213 and the fifth regulating valve 215 are provided to respectively regulate the flow of the hot molten salt entering the first hot molten salt supply pipeline 2021 and the second hot molten salt supply pipeline 2022. Preferably, the fourth regulating valve 213, the third shut-off valve 214 and the fifth regulating valve 215 are all connected to the control system, and of course a manual regulating valve can also be used.

[0060] The steam-water cooling molten salt system 3 includes a molten salt cooler 31, a water tank 32, a water pump 33 and a sixth regulating valve 305. The water pump 33 is arranged on the water supply pipeline 301, the inlet of the water pump 33 is connected to the outlet of the water tank 32, and the outlet of the water pump 33 is connected to the water inlet of the molten salt cooler 31. The water pump 33 is preferably a variable frequency pump. A safety valve 307 and a drain valve 308 are arranged on the molten salt cooler 31, and a fourth bypass 303 connected in parallel with the water pump 33 is arranged on the water supply pipeline 301, and a fourth bypass valve 304 is arranged on the fourth bypass 303. During the test, the water tank 32 is first filled with water, the water pump 33 is started, the fourth bypass valve 304 is opened, and the water pump 33 recirculation is established. Then open the sixth regulating valve 305, close the fourth bypass valve 304, fill the molten salt cooler 31 with water, close the drain valve 308 after the water quality is qualified, and close the exhaust valve 306 when the water level reaches the normal liquid level. Start the third electric heater 34 to preheat the water inside the molten salt cooler 31. When the water temperature in the molten salt cooler 31 reaches above the crystallization point of the molten salt, the molten salt is transported to the molten salt cooler 31. Preferably, the water pump 33, the sixth regulating valve 305 and the fourth bypass valve 304 are all connected to the control system. A flow measurement element and a pressure measurement element connected to the control system are provided on the water supply pipeline 301.

[0061] Furthermore, all molten salt pipelines, such as the cold molten salt supply pipeline 201, the heat exchanger molten salt delivery pipeline 212, the hot molten salt delivery pipeline 103, the mixed molten salt supply pipeline 203 and the molten salt return pipeline 302, are provided with heating belts and temperature detection elements, and the temperature detection elements are connected to the control system. At the same time, each of the above pipelines is provided with a flow measurement element and a pressure measurement element connected to the control system. Figure 1The letter F shown in the figure represents a flow measurement element, P represents a pressure measurement element, and T represents a temperature measurement element.

[0062] In addition, an embodiment of the present invention further discloses a molten salt heat storage and heat release method, which uses the above-mentioned molten salt heat storage and heat release device and includes the following steps:

[0063] S1, start the boiler 11 and open the bypass flue 102;

[0064] First, establish the convection heating surface 111 and the low-temperature economizer 14 cooling cycle inside the boiler 11, open the first baffle 106, start the boiler 11, and when the flue gas temperature in the main flue 101 reaches the preset temperature, open the second baffle 107 and the third baffle 108 to allow the flue gas to enter the molten salt heat exchanger 12. The flue gas temperature and flow rate of the bypass flue 102 can be adjusted by adjusting the combustion conditions of the boiler 11 and the opening degrees of the first baffle 106, the second baffle 107 and the third baffle 108.

[0065] S2, heating the cold molten salt and conveying the hot molten salt to the hot salt tank 22;

[0066] When the flue gas temperature in the bypass flue 102 meets the salt feeding condition, the cold molten salt in the cold salt tank 21 is transported to the molten salt heat exchanger 12, and is stored in the hot salt tank 22 after the temperature is increased, thereby realizing the heat storage process of the molten salt.

[0067] Specifically, the first electric heater 23 is turned on to heat the cold molten salt stored in the cold salt tank 21 to a preset temperature range, the first shut-off valve 204 and the second bypass valve 207 are opened, the cold salt pump 25 is started, and the minimum flow of the cold salt pump 25 is established. Then the second regulating valve 210, the first bypass valve 105, and the first regulating valve 218 are opened in sequence. When the inlet flue gas temperature in the bypass flue 102 meets the salt inlet condition, the opening of the first regulating valve 218 and the second bypass valve 207 is reduced to gradually fill the molten salt heat exchanger 12 with molten salt. When the liquid level of the outlet container 13 reaches the preset liquid level, the first bypass valve 105 is closed, and the opening of the first regulating valve 218 is adjusted to keep the liquid level in the outlet container 13 stable.

[0068] S3, mixing molten salt to heat water, and returning to the cold salt tank 21;

[0069] After the mixed molten salt heats water in the molten salt cooler 31 , it returns to the cold salt tank 21 through the molten salt return pipeline 302 . The water turns into water vapor and is discharged through the steam outlet, thus realizing the heat release process of the molten salt.

[0070] Specifically, first fill the water tank 32 with water, start the water pump 33, open the fourth bypass valve 304, and establish the recirculation of the water pump 33. Open the sixth regulating valve 305, reduce the opening of the fourth bypass valve 304, fill the molten salt cooler 31 with water, close the drain valve 308 after the water quality is qualified, close the exhaust valve 306 when the water level reaches the normal liquid level, and start the first electric heater 23 to heat the stored water inside the molten salt cooler 31.

[0071] When the water temperature in the molten salt cooler 31 is higher than the crystallization point of the molten salt, the first shut-off valve 204 and the second bypass valve 207 are opened, the cold salt pump 25 is started, and the minimum flow of the cold salt pump 25 is established. At the same time, the second shut-off valve 205 and the third bypass valve 209 are opened, the hot salt pump 26 is started, and the minimum flow of the hot salt pump 26 is established. The third shut-off valve 214 and the third regulating valve 211 are opened to establish a cold salt flow cycle. The speed of the hot salt pump 26 is adjusted to be synchronized with the cold salt pump 25, and the fifth regulating valve 215 is gradually opened to achieve the inlet temperature control of the molten salt cooler 31 by mixing cold molten salt and hot molten salt. According to needs, the speed of the cold salt pump 25, the opening of the second bypass valve 207, the speed of the hot salt pump 26, and the opening of the third bypass valve 209 are adjusted to make the flow of the mixed molten salt meet the requirements. During the entire process of the mixed molten salt entering, the pressure of the molten salt cooler 31 is adjusted to be within the normal working range. When overpressure occurs, the safety valve 307 acts to protect the safety of the equipment.

[0072] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0074] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0075] The terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0076] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Molten salt heat storage and heat release device, characterized in that: include: A flue gas heated molten salt heat storage system (1), the flue gas heated molten salt heat storage system (1) comprising a boiler (11) and a molten salt heat exchanger (12), a main flue (101) of the boiler (11) being provided with a bypass flue (102), the bypass flue (102) being in communication with the molten salt heat exchanger (12); A molten salt storage system (2), the molten salt storage system (2) comprising a cold salt tank (21) and a hot salt tank (22), the cold salt tank (21) being connected to the molten salt heat exchanger (12) via a cold molten salt supply pipeline (201) and a heat exchanger molten salt delivery pipeline (212), the molten salt heat exchanger (12) being connected to the hot salt tank (22) via a hot molten salt delivery pipeline (103), a first bypass (104) being arranged between the heat exchanger molten salt delivery pipeline (212) and the hot molten salt delivery pipeline (103) and being connected in parallel with the molten salt heat exchanger (12), the first bypass (104) being arranged with a first bypass valve (105), the cold salt tank (21) being arranged with a first electric heater (23), and the hot salt tank (22) being arranged with a second electric heater (24); A steam-water cooling molten salt system (3), the steam-water cooling molten salt system (3) comprising a molten salt cooler (31) and a water tank (32), the water tank (32) being connected to the molten salt cooler (31) via a water supply pipeline (301), the molten salt cooler (31) being provided with a steam outlet; the hot salt tank (22) being provided with a hot molten salt supply pipeline (202), the cold molten salt supply pipeline (201) and the hot molten salt supply pipeline (202) being merged to form a mixed molten salt supply pipeline (203), the mixed molten salt supply pipeline (203) being connected to the molten salt cooler (31), the molten salt cooler (31) being connected to the cold salt tank (21) via a molten salt return pipeline (302), the molten salt cooler (31) being provided with a third electric heater (34); A control system, wherein the flue gas heating molten salt heat storage system (1), the molten salt storage system (2) and the steam-water cooling molten salt system (3) are all connected to the control system.

2. The molten salt heat storage and heat release device according to claim 1, characterized in that: The hot molten salt transport pipeline (103) is provided with an outlet container (13) and a first regulating valve (218), wherein the first regulating valve (218) is arranged downstream of the outlet container (13), and the outlet container (13) is connected to the hot salt tank (22).

3. The molten salt heat storage and heat release device according to claim 1, characterized in that: A first baffle (106) is arranged in the main flue (101) of the boiler (11), and a second baffle (107) and a third baffle (108) are arranged in the bypass flue (102), wherein the second baffle (107) is arranged at the flue gas inlet of the molten salt heat exchanger (12), and the third baffle (108) is arranged at the flue gas outlet of the molten salt heat exchanger (12); The flue gas outlet of the molten salt heat exchanger (12) is connected to the low-temperature economizer (14) of the boiler (11).

4. The molten salt heat storage and heat release device according to claim 1, characterized in that: The cold molten salt supply pipeline (201) is provided with a cold salt pump (25), and the outlet of the cold salt pump (25) is provided with a first shut-off valve (204); The hot molten salt supply pipeline (202) is provided with a hot salt pump (26), and the outlet of the hot salt pump (26) is provided with a second shut-off valve (205).

5. The molten salt heat storage and heat release device according to claim 4, characterized in that: The cold molten salt supply pipeline (201) is provided with a second bypass (206) connected in parallel with the cold salt pump (25), the second bypass (206) is connected to the cold salt tank (21), and the second bypass (206) is provided with a second bypass valve (207); The hot molten salt supply pipeline (202) is provided with a third bypass (208) connected in parallel with the hot salt pump (26); the third bypass (208) is connected to the hot salt tank (22); and the third bypass valve (209) is provided on the third bypass (208).

6. The molten salt heat storage and heat release device according to claim 1, characterized in that: The cold molten salt supply pipeline (201) is split into a first cold molten salt supply pipeline (2011) and a second cold molten salt supply pipeline (2012); the first cold molten salt supply pipeline (2011) is connected to the molten salt heat exchanger (12); the second cold molten salt supply pipeline (2012) is connected to the molten salt cooler (31); a second regulating valve (210) is provided on the first cold molten salt supply pipeline (2011); and a third regulating valve (211) is provided on the second cold molten salt supply pipeline (2012).

7. The molten salt heat storage and heat release device according to claim 6, characterized in that: The hot molten salt supply pipeline (202) is split to form a first hot molten salt supply pipeline (2021) and a second hot molten salt supply pipeline (2022); the first hot molten salt supply pipeline (2021) and the first cold molten salt supply pipeline (2011) are combined to form a heat exchanger molten salt delivery pipeline (212); the heat exchanger molten salt delivery pipeline (212) is connected to the molten salt heat exchanger (12); and a fourth regulating valve (213) is provided on the first hot molten salt supply pipeline (2021); The second hot molten salt supply pipeline (2022) and the second cold molten salt supply pipeline (2012) are combined to form the mixed molten salt supply pipeline (203), the mixed molten salt supply pipeline (203) is provided with a third shut-off valve (214), and the second hot molten salt supply pipeline (2022) is provided with a fifth regulating valve (215).

8. The molten salt heat storage and heat release device according to claim 7, characterized in that: The cold molten salt supply pipeline (201), the heat exchanger molten salt delivery pipeline (212), the hot molten salt delivery pipeline (103), the mixed molten salt supply pipeline (203) and the molten salt return pipeline (302) are all provided with heating belts and temperature detection elements, and the temperature detection elements are connected to the control system.

9. The molten salt heat storage and heat release device according to claim 1, characterized in that: The water supply pipeline (301) is provided with a water pump (33), a sixth regulating valve (305) and a fourth bypass (303) connected in parallel with the water pump (33); the sixth regulating valve (305) is provided downstream of the water pump (33); and the fourth bypass (303) is provided with a fourth bypass valve (304); The water supply pipeline (301) is provided with a flow detection element and a pressure detection element connected to the control system.

10. A molten salt heat storage and heat release method, using the molten salt heat storage and heat release device according to any one of claims 1 to 9, characterized in that: The steps include: S1, starting the boiler (11) and opening the bypass flue (102); When the temperature of the flue gas in the main flue (101) reaches a preset temperature, the bypass flue (102) is opened to allow the flue gas to enter the molten salt heat exchanger (12); S2, heating the cold molten salt and conveying the hot molten salt to the hot salt tank (22); When the flue gas temperature in the bypass flue (102) meets the salt feeding condition, the cold molten salt in the cold salt tank (21) is transported to the molten salt heat exchanger (12), and after the temperature is increased, it is stored in the hot salt tank (22), thereby realizing a molten salt heat storage process; S3, mixing molten salt to heat water, and returning to the cold salt tank (21); The mixed molten salt heats water in the molten salt cooler (31) and then returns to the cold salt tank (21) through the molten salt return pipeline (302), and the water is converted into water vapor and discharged through the steam outlet, thereby realizing the heat release process of the molten salt.

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