An integrated system for heat collection, heat storage, and heat exchange, and its usage method.

Abstract

This invention relates to an integrated system for heat collection, storage, and exchange, and its usage method. The system includes a molten salt storage tank, a molten salt pump, a molten salt heater, an evaporator, and a solar collector. The solar collector includes vacuum collector tubes, an upper manifold, and a lower manifold. Multiple vacuum collector tubes surround the outer surface of the molten salt storage tank, forming a vacuum collector tube array. The upper and lower manifolds are located at the upper and lower ends of the vacuum collector tube array, respectively, and are connected to each vacuum collector tube. The molten salt storage tank consists of an inner wall and an outer wall, with a vacuum interlayer formed between the inner and outer walls. A fixed baffle is installed inside the molten salt storage tank, dividing its internal space into multiple storage chambers. Each storage chamber is connected to the cold salt inlet of the solar collector and the hot salt inlet of the evaporator via the molten salt pump. The hot salt outlet of the solar collector is connected to the cold salt inlet of the molten salt heater, and the hot salt outlet of the molten salt heater and the cold salt outlet of the evaporator are both connected to their respective storage chambers. The system has a compact structure and a high degree of integration, which reduces operating costs.

Description

Technical Field

[0001] This invention belongs to the field of molten salt heat storage and release technology, specifically relating to an integrated system for heat collection, heat storage and heat exchange and its usage method. Background Technology

[0002] With the increasing development of clean energy, the installed capacity of new energy sources maintains a high growth rate, and its proportion continues to increase, accelerating the green transformation of the energy structure. The continuous increase in the scale of clean energy power supply poses a significant challenge to the stability of the power grid, resulting in severe wind and solar power curtailment. The issue of green energy consumption is becoming increasingly prominent. The inherent uncertainty and instability of clean energy makes its application very difficult. To effectively solve the problem of wind and solar power curtailment and improve electricity utilization, energy storage technology has emerged, which can effectively improve the problem of wind and solar power consumption.

[0003] Currently, molten salt energy storage technology is widely used in solar thermal power plants and heating stations due to its wide heat storage temperature range, high stability, and long lifespan. Molten salt storage tanks are the carriers for storing the heat storage medium. Existing molten salt energy storage technologies mainly use a dual-tank configuration to store the heat storage medium. This approach has the following drawbacks: 1. Low integration and compactness of the system, resulting in excessive floor space; 2. Excessive use of high-temperature and corrosion-resistant materials for manufacturing the tanks, leading to high investment costs; 3. Excessive material loss in the tank foundation and external insulation layer, resulting in significant investment pressure; 4. Storage of cold and hot molten salt requires two molten salt tanks, meaning one tank is always idle during operation, with the molten salt medium occupying only half the space of the two tanks, resulting in relatively low tank space utilization.

[0004] In view of this, the present invention proposes an integrated system for heat collection, heat storage and heat exchange and a method of using it. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide an integrated system for heat collection, heat storage and heat exchange and a method of using it.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An integrated system for heat collection, storage, and exchange includes a molten salt storage tank, a molten salt pump, a molten salt heater, an evaporator, and a solar collector; characterized in that...

[0008] The solar collector is used for preheating low-temperature molten salt and includes a vacuum collector tube, an upper manifold, and a lower manifold. Multiple vacuum collector tubes surround the outer surface of the molten salt storage tank to form a vacuum collector tube array. The upper and lower manifolds are located in a ring at the upper and lower ends of the vacuum collector tube array, and both the upper and lower manifolds are connected to each vacuum collector tube.

[0009] The molten salt storage tank consists of an inner wall and an outer wall, with a vacuum interlayer between them. The molten salt storage tank is equipped with fixed baffles that divide the internal space of the tank into multiple storage chambers. Each storage chamber is connected to the cold salt inlet of the solar collector and the hot salt inlet of the evaporator via a molten salt pump. The hot salt outlet of the solar collector is connected to the cold salt inlet of the molten salt heater. The hot salt outlet of the molten salt heater and the cold salt outlet of the evaporator are both connected to their respective storage chambers.

[0010] Furthermore, the molten salt storage tank is equipped with two mutually perpendicular fixed baffles, which evenly divide the internal space of the molten salt storage tank into four storage chambers arranged clockwise. A first molten salt valve to a fourth molten salt valve are respectively provided between the molten salt pump and the first, second, third, and fourth storage chambers. A fifth molten salt valve and a sixth molten salt valve are respectively provided between the molten salt pump and the cold salt inlet of the solar collector and the hot salt inlet of the evaporator. A seventh molten salt valve is provided at the hot salt outlet of the molten salt heater, and an eighth molten salt valve is provided at the cold salt outlet of the evaporator. The first, second, third, and fourth storage chambers are respectively connected to the hot salt outlet of the molten salt heater and the cold salt outlet of the evaporator through a ninth to a twelfth molten salt valve.

[0011] The usage of the above system includes the following:

[0012] Assuming that during the initial operation of the system, the first, second, and third storage chambers of the molten salt tank all contain low-temperature molten salt, while the fourth storage chamber contains a small amount of bottom salt;

[0013] During heat storage, the fifth molten salt valve, the seventh molten salt valve, and the molten salt pump are normally open, while the sixth molten salt valve and the eighth molten salt valve are normally closed. When the first molten salt valve and the twelfth molten salt valve are opened, the low-temperature molten salt in the first-zone storage chamber enters the solar collector for preheating under the action of the molten salt pump. The preheated low-temperature molten salt enters the molten salt heater for further heating to obtain high-temperature molten salt. The high-temperature molten salt flows out from the molten salt heater and enters the fourth-zone storage chamber. When the liquid level of the molten salt in the first-zone storage chamber reaches the minimum operating liquid level, the first molten salt valve and the twelfth molten salt valve are closed. After the low-temperature molten salt in the first-zone storage chamber completes heat storage, it is stored in the fourth-zone storage chamber.

[0014] The second and ninth molten salt valves are opened, and the low-temperature molten salt in the second-domain storage chamber enters the solar collector for preheating under the action of the molten salt pump. The preheated low-temperature molten salt enters the molten salt heater for further heating to obtain high-temperature molten salt. The high-temperature molten salt flows out from the molten salt heater and enters the first-domain storage chamber. When the liquid level of the molten salt in the second-domain storage chamber reaches the minimum operating liquid level, the second and ninth molten salt valves are closed. After the low-temperature molten salt in the second-domain storage chamber completes heat storage, it is stored in the first-domain storage chamber.

[0015] Open the third and tenth molten salt valves. The low-temperature molten salt in the three-domain storage chamber enters the solar collector for preheating under the action of the molten salt pump. The preheated low-temperature molten salt enters the molten salt heater for further heating to obtain high-temperature molten salt. The high-temperature molten salt flows out from the molten salt heater and enters the second-domain storage chamber. When the liquid level of the molten salt in the third-domain storage chamber reaches the minimum operating liquid level, close the third and tenth molten salt valves. The low-temperature molten salt in the third-domain storage chamber is stored in the second-domain storage chamber after completing heat storage. Close the fifth and seventh molten salt valves and the molten salt pump to complete heat storage. At this time, the first, second, and fourth domain storage chambers of the molten salt tank contain high-temperature molten salt, and the third domain storage chamber contains a small amount of bottom salt.

[0016] During heat release, the sixth and eighth molten salt valves and the molten salt pump are normally open, while the fifth and seventh molten salt valves are normally closed. When the fourth and eleventh molten salt valves are opened, the high-temperature molten salt in the fourth-domain storage chamber enters the evaporator for heat exchange under the action of the molten salt pump. The low-temperature molten salt obtained from the heat exchange flows back to the third-domain storage chamber. When the liquid level of the molten salt in the fourth-domain storage chamber reaches the minimum operating liquid level, the fourth and eleventh molten salt valves are closed. After the high-temperature molten salt in the fourth-domain storage chamber has completed heat release, it is stored in the third-domain storage chamber.

[0017] Open the first molten salt valve and the twelfth molten salt valve. The high-temperature molten salt in the first storage chamber enters the evaporator for heat exchange under the action of the molten salt pump. The low-temperature molten salt obtained from the heat exchange enters the fourth storage chamber. When the liquid level of the molten salt in the first storage chamber reaches the minimum operating liquid level, close the first molten salt valve and the twelfth molten salt valve. After the high-temperature molten salt in the first storage chamber completes the heat exchange, it is stored in the fourth storage chamber.

[0018] Open the second and ninth molten salt valves. The high-temperature molten salt in the second-domain storage chamber enters the evaporator for heat exchange under the action of the molten salt pump. The low-temperature molten salt obtained from the heat exchange flows back to the first-domain storage chamber. When the liquid level of the molten salt in the second-domain storage chamber reaches the minimum operating liquid level, close the second and ninth molten salt valves. After the high-temperature molten salt in the second-domain storage chamber completes the heat exchange, it is stored in the first-domain storage chamber. Close the sixth and eighth molten salt valves and the molten salt pump to complete the heat release. At this time, the first, third, and fourth-domain storage chambers of the molten salt tank store low-temperature molten salt, while the second-domain storage chamber stores a small amount of bottom salt.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The system uses solar collectors installed on the surface of the molten salt storage tank to absorb and utilize solar energy. The entire system has a compact structure, high degree of integration, small footprint, wider applicability, reduced application of other auxiliary equipment, and lower operating costs. The solar collectors convert solar energy into heat energy and store it in the low-temperature molten salt to preheat the low-temperature molten salt, thereby further increasing the temperature of the low-temperature molten salt, reducing the system's power consumption, shortening the time for the molten salt to reach the operating temperature, accelerating the system's heating efficiency, and thus making the system more efficient and significantly reducing operating costs.

[0021] (2) The molten salt medium is stored in a single molten salt storage tank with a vacuum jacket. Compared with the original double-tank molten salt energy storage system, the vacuum jacket replaces the outer insulation layer of the tank, which not only helps to save the investment cost of the outer insulation layer of the tank, but also effectively reduces the heat dissipation of the molten salt medium in the tank to the surrounding air, reduces the heat loss of the entire system, and thus ensures the safe and stable operation of the system. The single tank replaces the double tank in the system of the present invention to store the molten salt medium, which reduces the construction cost of the tank foundation and the application of high temperature and corrosion resistant steel in the manufacture of the tank, thereby saving the enterprise investment cost of steel materials.

[0022] (3) The molten salt storage tank has mutually perpendicular fixed baffles inside, which divide the internal space of the molten salt storage tank into multiple storage chambers. Except for one storage chamber that retains the bottom salt, the other storage chambers store molten salt medium. By controlling the opening and closing of the corresponding valves, the molten salt medium in different storage chambers of a single molten salt storage tank can be transferred between each other, thus realizing the storage and heat release process of the entire system, thereby realizing the dual-use function of a single tank. Compared with a dual-tank molten salt energy storage system, this invention improves the space utilization rate of the molten salt storage tank. Taking a molten salt storage tank with four storage chambers as an example, three-quarters of the space in a single molten salt storage tank is used to store molten salt medium, which increases the space utilization rate of the molten salt storage tank by 25%. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the installation of the solar collector and molten salt storage tank of the present invention;

[0024] Figure 2 This is a simplified connection diagram of the present invention, excluding the molten salt storage tank;

[0025] Figure 3 This is a schematic diagram of the internal structure of the molten salt storage tank of the present invention;

[0026] Figure 4 This is a radial cross-sectional view of the solar collector and molten salt storage tank of the present invention;

[0027] Figure 5 This is a cross-sectional view of the solar collector of the present invention;

[0028] Figure 6 This is a schematic diagram of the storage state of the molten salt medium in each storage compartment of the molten salt storage tank of the present invention after initial storage, heat storage completion, and heat release completion.

[0029] In the diagram, 1. Molten salt storage tank; 2. Molten salt pump; 3. Molten salt heater; 4. Evaporator; 5. Solar collector;

[0030] 101. Primary storage chamber; 102. Secondary storage chamber; 103. Tertiary storage chamber; 104. Quadruple storage chamber; 105. Fixed baffle; 106. Vacuum jacket; 501. Vacuum collector tube; 502. Upper connecting manifold; 503. Lower connecting manifold;

[0031] a~l: First molten salt valve~twelfth molten salt valve l; A~D: First molten salt rising pipe~fourth molten salt rising pipe; E~H: First molten salt falling pipe~fourth molten salt falling pipe; M, first molten salt transport pipe; N, second molten salt transport pipe; P, third molten salt transport pipe; Q, fourth molten salt transport pipe. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings. Specific embodiments are only used to further illustrate the present invention in detail and do not limit the scope of protection of this application.

[0033] This invention is an integrated system for heat collection, heat storage, and heat exchange (see [link]). Figure 1-6 The system includes a molten salt storage tank 1, a molten salt pump 2, a molten salt heater 3, an evaporator 4, and a solar collector 5.

[0034] The solar collector 5 is wrapped around the outside of the molten salt storage tank 1, preheating the low-temperature molten salt by absorbing solar energy. The molten salt storage tank 1 consists of an inner wall and an outer wall, with a vacuum interlayer 106 formed between them. The vacuum interlayer 106 is evacuated to improve the heat storage effect of the molten salt storage tank 1. A vertical fixed baffle 105 is installed inside the molten salt storage tank 1, with its height matching that of the inner wall. The fixed baffle 105 is welded to the inner wall of the molten salt storage tank 1, dividing the internal space of the molten salt storage tank 1 into multiple storage chambers. Each storage chamber is equipped with a level transmitter. The system monitors the liquid level in real time. One end of the molten salt pump 2 is connected to each storage chamber via a molten salt rising pipe, and the other end is connected to the solar collector 5 via a first molten salt transport pipe M. It is also connected to the evaporator 4 via a second molten salt transport pipe N. The solar collector 5 is also connected to the molten salt heater 3. The molten salt heater 3 is connected to each storage chamber via a third molten salt transport pipe P and its respective molten salt falling pipe. The output end of the evaporator 4 is connected to each storage chamber via a fourth molten salt transport pipe Q and its respective molten salt falling pipe. Molten salt valves are installed on each molten salt rising pipe, molten salt transport pipe, and molten salt falling pipe to control the opening and closing of the corresponding pipelines.

[0035] The solar collector 5 and the molten salt heater 3 together form a molten salt heat storage system, and the evaporator 4 is used for molten salt heat release. During heat storage, the low-temperature molten salt in each storage chamber is pressurized by the molten salt pump 2 and then fed into the solar collector 5 for preheating. The preheated molten salt is further heated in the molten salt heater 3 to obtain high-temperature molten salt, which is then returned to the storage chamber for storage. During heat release, the high-temperature molten salt in each storage chamber is pressurized by the molten salt pump 2 and then enters the evaporator 4 for heat exchange, generating steam for use at the heat-consuming end of the plant area.

[0036] In this embodiment, the molten salt storage tank 1 is provided with two mutually perpendicular fixed baffles 105, which evenly divide the internal space of the molten salt storage tank 1 into a first-domain storage chamber 101, a second-domain storage chamber 102, a third-domain storage chamber 103, and a fourth-domain storage chamber 104 arranged clockwise. The first-domain storage chamber 101 is connected to the molten salt pump 2 through a first molten salt rising pipe A, and is also connected to the third molten salt transport pipe P and the fourth molten salt transport pipe Q through a first molten salt descending pipe E. The first molten salt rising pipe A is provided with a first molten salt valve a, and the first molten salt descending pipe E is provided with a ninth molten salt valve i. The second-domain storage chamber 102 is connected to the molten salt pump 2 through a second molten salt rising pipe B, and is also connected to the third molten salt transport pipe P and the fourth molten salt transport pipe Q through a second molten salt descending pipe F. The second molten salt rising pipe B is provided with a second molten salt valve b, and the second molten salt descending pipe F is provided with a tenth molten salt valve j. The third-domain storage chamber 103 is connected to the molten salt pump 2 through a first molten salt rising pipe A, and is also connected to the third molten salt transport pipe P and the fourth molten salt transport pipe Q through a second molten salt descending pipe F. The second molten salt rising pipe B is provided with a second molten salt valve b, and the second molten salt descending pipe F is provided with a tenth molten salt valve j. The three molten salt rising pipes C are connected to the molten salt pump 2, and are connected to the third molten salt transport pipe P and the fourth molten salt transport pipe Q respectively through the third molten salt descending pipe G. The third molten salt rising pipe C is equipped with a third molten salt valve c, and the third molten salt descending pipe G is equipped with an eleventh molten salt valve k. The four-domain storage chamber 104 is connected to the molten salt pump 2 through the fourth molten salt rising pipe D, and is connected to the third molten salt transport pipe P and the fourth molten salt transport pipe Q respectively through the fourth molten salt descending pipe H. The fourth molten salt rising pipe D is equipped with a fourth molten salt valve d, and the fourth molten salt descending pipe H is equipped with a twelfth molten salt valve l. All molten salt rising pipes and molten salt descending pipes are led out from the top of the molten salt storage tank 1. The first molten salt transport pipe M is equipped with a fifth molten salt valve e, the second molten salt transport pipe N is equipped with a sixth molten salt valve f, the third molten salt transport pipe P is equipped with a seventh molten salt valve g, and the fourth molten salt transport pipe Q is equipped with an eighth molten salt valve h.

[0037] The solar collector 5 includes a vacuum collector tube 501, an upper manifold 502, and a lower manifold 503; multiple vacuum collector tubes 501 surround the outside of the molten salt storage tank 1 to form a vacuum collector tube array; the upper manifold 502 and the lower manifold 503 are both annular pipes, located at the upper and lower ends of the vacuum collector tube array, respectively, and connected to each vacuum collector tube 501.

[0038] The material used to manufacture the molten salt storage tank 1 should have high temperature and corrosion resistance, and can be, but is not limited to, 16MnR, J347H, and 13MnNiMoR. The fixed baffle 105 is made of steel plate with high temperature resistance, corrosion resistance, and easy weldability, and can be, but is not limited to, 019Cr18MoTi, 430J1L, and 00Cr17Ni14Mo2. The outer surface of the fixed baffle 105 is coated with a thermal insulation coating, which is required to have low thermal conductivity and excellent thermal insulation effect. The thermal conductivity of the thermal insulation coating is 0.033W / m / k.

[0039] In this embodiment, the outer surfaces of the upper manifold 502 and lower manifold 503 of the heat collection device 5, the evaporator 4, the molten salt heater 3, and each molten salt pipe are all wrapped with heat-insulating and fire-resistant insulation material. The insulation material is preferably selected, but is not limited to, having a density of 128 kg / m³. 3 The aluminum silicate fiber blanket material has a length*width*thickness of 3600*610*50mm. The thermal conductivity is required to be maintained at 0.041W / m / k at 200℃, 0.068W / m / k at 400℃, and 0.107W / m / k at 600℃, thereby reducing the heat loss of the system.

[0040] Solar collector 5 uses solar energy as its energy source, converting it into the internal energy of low-temperature molten salt, thereby increasing the temperature of the low-temperature molten salt to obtain high-temperature molten salt. The molten salt heater 3 is powered by curtailed wind and solar power or clean electricity, effectively solving the problem of wind and solar power consumption and improving grid stability and energy utilization. Evaporator 4 is a horizontal shell-and-tube evaporator; the high-temperature molten salt operates through the tube side, while the heat exchange medium operates through the shell side.

[0041] The usage method of the above system is as follows:

[0042] by Figure 6 Taking the initial operation of the system as an example, the storage state of the molten salt storage tank 1 is shown. The first storage chamber 101, the second storage chamber 102, and the third storage chamber 103 store low-temperature molten salt, while the fourth storage chamber 104 is in an idle state and stores a small amount of bottom salt.

[0043] Heat storage process: During heat storage, the fifth molten salt valve e, the seventh molten salt valve g, and the molten salt pump 2 are normally open, while the sixth molten salt valve f and the eighth molten salt valve h are normally closed. First, the first molten salt valve a and the twelfth molten salt valve l are opened. Under the pressure of the molten salt pump 2, the low-temperature molten salt in the first storage chamber 101 enters the solar collector 5 through the first molten salt rising pipe A and the first molten salt transport pipe M for heating. The solar collector 5 absorbs solar energy and converts it into heat energy stored in the low-temperature molten salt, causing the temperature of the low-temperature molten salt to rise and preheat it. The preheated low-temperature molten salt then passes through the third... Molten salt is transported into molten salt heater 3 via molten salt transport pipeline P. Molten salt heater 3 uses green electricity generated from abandoned wind and solar power to further heat the preheated low-temperature molten salt to obtain high-temperature molten salt. The high-temperature molten salt flows out of molten salt heater 3 and enters the four-domain storage chamber 104 through the fourth molten salt descent pipeline H. The system monitors the liquid level of molten salt in the first-domain storage chamber 101 in real time through a radar liquid level transmitter in the first-domain storage chamber 101. When the minimum operating liquid level is reached, the first molten salt valve a and the twelfth molten salt valve l are closed. After the low-temperature molten salt in the first-domain storage chamber 101 has completed heat storage, it is stored in the four-domain storage chamber 104.

[0044] The second molten salt valve b and the ninth molten salt valve i are opened. Under the pressure of the molten salt pump 2, the low-temperature molten salt in the secondary storage chamber 102 enters the solar collector 5 through the second molten salt rising pipe B and the first molten salt transport pipe M for heating. The solar collector 5 absorbs solar energy and converts it into heat energy stored in the low-temperature molten salt, thereby raising the temperature of the low-temperature molten salt and preheating it. The preheated low-temperature molten salt is then transported through the third molten salt transport pipe P into the molten salt heater 3. The molten salt heater 3 utilizes the surplus wind... The green electricity generated by the abandoned solar power further heats the preheated low-temperature molten salt to obtain high-temperature molten salt. The high-temperature molten salt flows out from the molten salt heater 3 and enters the first molten salt downcomer E into the first-domain storage chamber 101. The system monitors the liquid level of the molten salt in the second-domain storage chamber 102 in real time through the radar liquid level transmitter in the second-domain storage chamber 102. When the minimum operating liquid level is reached, the second molten salt valve b and the ninth molten salt valve i are controlled to close. After the low-temperature molten salt in the second-domain storage chamber 102 has completed heat storage, it is stored in the first-domain storage chamber 101.

[0045] The third molten salt valve c and the tenth molten salt valve j are opened. Under the pressure of the molten salt pump 2, the low-temperature molten salt in the three-domain storage chamber 103 enters the solar collector 5 through the third molten salt riser pipe C and the first molten salt transport pipe M for heating. The solar collector 5 absorbs solar energy and converts it into heat energy stored in the low-temperature molten salt, causing the temperature of the low-temperature molten salt to rise and preheat it. The preheated low-temperature molten salt is transported through the third molten salt transport pipe P into the molten salt heater 3. The molten salt heater 3 uses green electricity generated by wind and solar power curtailment to further heat the preheated low-temperature molten salt to obtain high-temperature molten salt. The high-temperature molten salt flows out of the molten salt heater 3 and passes through the second molten salt... Salt descends through pipe F into the secondary storage chamber 102. The system monitors the molten salt level in the tertiary storage chamber 103 in real time using a radar level transmitter. When the minimum operating level is reached, the third molten salt valve c and the tenth molten salt valve j are closed. After the low-temperature molten salt in the tertiary storage chamber 103 has completed heat storage, it is stored in the secondary storage chamber 102. At the same time, the fifth molten salt valve e, the seventh molten salt valve g, and the molten salt pump 2 are closed, thus completing the entire heat storage process. At this time, the primary storage chamber 101, the secondary storage chamber 102, and the fourth storage chamber 104 of the molten salt storage tank 1 contain high-temperature molten salt, while the tertiary storage chamber 103 is idle and only contains a small amount of bottom salt.

[0046] Heat release process: When there is a need for heat, the system adjusts the sixth molten salt valve f, the eighth molten salt valve h, and the molten salt pump 2 to the normally open state, and the fifth molten salt valve e and the seventh molten salt valve g to the normally closed state. First, the fourth molten salt valve d and the eleventh molten salt valve k are opened. Under the action of the molten salt pump 2, the high-temperature molten salt in the four-domain storage chamber 104 is transported into the evaporator 4 through the fourth molten salt rising pipe D and the second molten salt transport pipe N to exchange heat with the plant feedwater. The molten salt medium operates through the tube side of the evaporator 4, and the feedwater operates through the shell side of the evaporator 4. The heat is transferred to the feed water to vaporize it and generate high-temperature steam for heating users; the low-temperature molten salt obtained from the heat exchange flows out through the cold salt outlet of the evaporator 4, flows through the fourth molten salt transport pipe Q and the third molten salt downflow pipe G into the three-domain storage chamber 103 for storage; the system monitors the liquid level of the molten salt in the four-domain storage chamber 104 in real time through the radar liquid level transmitter in the four-domain storage chamber 104. When the minimum operating liquid level is reached, the fourth molten salt valve d and the eleventh molten salt valve k are closed. After the high-temperature molten salt in the four-domain storage chamber 104 has completed the heat release, it is stored in the three-domain storage chamber 103.

[0047] The first molten salt valve a and the twelfth molten salt valve l are opened. Under the action of the molten salt pump 2, the high-temperature molten salt in the first-domain storage chamber 101 is transported into the evaporator 4 through the first molten salt rising pipe A and the second molten salt transport pipe N to exchange heat with the plant feedwater. The heat of the high-temperature molten salt is transferred to the feedwater, causing it to vaporize and generate high-temperature steam for heating users. The low-temperature molten salt obtained from the heat exchange flows out through the cold salt outlet of the evaporator 4 and flows through the fourth molten salt transport pipe Q and the fourth molten salt descending pipe H into the fourth-domain storage chamber 104. The system monitors the liquid level of the molten salt in the first-domain storage chamber 101 in real time through the radar liquid level transmitter in the first-domain storage chamber 101. When the minimum operating liquid level is reached, the first molten salt valve a and the twelfth molten salt valve l are closed. After the high-temperature molten salt in the first-domain storage chamber 101 completes the heat exchange, it is stored in the fourth-domain storage chamber 104.

[0048] Opening the second molten salt valve b and the ninth molten salt valve i, under the action of the molten salt pump 2, the high-temperature molten salt in the second-domain storage chamber 102 is transported through the second molten salt rising pipe B and the second molten salt transport pipe N into the evaporator 4 to exchange heat with the feedwater from the plant area. The heat carried by the high-temperature molten salt is transferred to the low-temperature feedwater, and the feedwater gains heat and vaporizes to generate steam for heating users. The low-temperature molten salt obtained from the heat exchange flows out from the cold salt outlet of the evaporator 4, flows through the fourth molten salt transport pipe Q and the first molten salt descending pipe E into the first-domain storage chamber 101; the system passes through the second-domain storage chamber 102. The radar level transmitter inside 02 monitors the liquid level of molten salt in the second-domain storage chamber 102 in real time. When the minimum operating liquid level is reached, the second molten salt valve b and the ninth molten salt valve i are closed. After the high-temperature molten salt in the second-domain storage chamber 102 completes heat exchange, it is stored in the first-domain storage chamber 101. At the same time, the sixth molten salt valve f, the eighth molten salt valve h, and the molten salt pump 2 are closed. The heat release process of the entire system is completed. The first-domain storage chamber 101, the third-domain storage chamber 103, and the fourth-domain storage chamber 104 of the molten salt storage tank 1 store low-temperature molten salt. The second-domain storage chamber 102 is in an idle state and only stores a small amount of bottom salt.

[0049] The order of heat storage and release of low-temperature molten salt in the above-mentioned storage cavities, as well as the corresponding storage cavities after heat storage and release are not restricted.

[0050] This system employs PLC control, with options including Siemens S7-1200, 1500 series, or Mitsubishi FR-FX3U, FR-FX2NC series. The PLC automatic control system not only manages the two heat exchange processes mentioned above but also controls the opening and closing of relevant molten salt valves by monitoring data collected by radar level transmitters in each chamber of molten salt storage tank 1. The entire system's heat exchange is achieved through the coordination of its components. All molten salt valves are automatically adjustable, controlling their opening and closing and valve opening degree by receiving electrical signals from the control system, thereby controlling the molten salt flow rate.

[0051] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A heat collecting, storing and exchanging integrated system, comprising a molten salt storage tank, a molten salt pump, a molten salt heater, an evaporator and a solar heat collector; characterized in that, the solar heat collector is used for preheating low-temperature molten salt and comprises vacuum heat collecting pipes, an upper connection header and a lower connection header; a plurality of vacuum heat collecting pipes are arranged around the outer surface of the molten salt storage tank to form a vacuum heat collecting pipe array; the upper connection header and the lower connection header are annularly arranged at the upper end and the lower end of the vacuum heat collecting pipe array, and the upper connection header and the lower connection header are in communication with each vacuum heat collecting pipe; the molten salt storage tank is divided into an inner layer wall and an outer layer wall, and a vacuum interlayer is formed between the inner layer wall and the outer layer wall; the molten salt storage tank is provided with a fixed baffle, and the internal space of the molten salt storage tank is divided into a plurality of domain storage cavities; each domain storage cavity is connected with the cold salt inlet of the solar heat collector and the hot salt inlet of the evaporator through the molten salt pump, the hot salt outlet of the solar heat collector is connected with the cold salt inlet of the molten salt heater, and the hot salt outlet of the molten salt heater and the cold salt outlet of the evaporator are connected with each domain storage cavity; the molten salt storage tank is provided with two mutually perpendicular fixed baffles, and the internal space of the molten salt storage tank is evenly divided into a first domain storage cavity, a second domain storage cavity, a third domain storage cavity and a fourth domain storage cavity arranged in a clockwise direction; the molten salt pump is provided with a first molten salt valve to a fourth molten salt valve between the first domain storage cavity, the second domain storage cavity, the third domain storage cavity and the fourth domain storage cavity; the molten salt pump is provided with a fifth molten salt valve and a sixth molten salt valve between the cold salt inlet of the solar heat collector and the hot salt inlet of the evaporator; the hot salt outlet of the molten salt heater is provided with a seventh molten salt valve, and the cold salt outlet of the evaporator is provided with an eighth molten salt valve; the first domain storage cavity, the second domain storage cavity, the third domain storage cavity and the fourth domain storage cavity are connected with the hot salt outlet of the molten salt heater and the cold salt outlet of the evaporator through a ninth molten salt valve to a twelfth molten salt valve.

2. The method of using the integrated heat collecting, heat storing and heat exchanging system according to claim 1, characterized in that, The method comprises the following contents: assuming that when the system is initially operated, low-temperature molten salt is stored in the first domain storage cavity, the second domain storage cavity and the third domain storage cavity of the molten salt storage tank, and a small amount of bottom salt is stored in the fourth domain storage cavity; when storing heat, the fifth molten salt valve, the seventh molten salt valve and the molten salt pump are in an open state, the sixth molten salt valve and the eighth molten salt valve are in a closed state; the first molten salt valve and the twelfth molten salt valve are opened, and the low-temperature molten salt in the first domain storage cavity enters the solar heat collector for preheating under the action of the molten salt pump, the preheated low-temperature molten salt enters the molten salt heater for further heating to obtain high-temperature molten salt; the high-temperature molten salt flows out of the molten salt heater and enters the fourth domain storage cavity; when the liquid level of the molten salt in the first domain storage cavity reaches the lowest operating liquid level, the first molten salt valve and the twelfth molten salt valve are closed, and the low-temperature molten salt in the first domain storage cavity is stored in the fourth domain storage cavity after completing the heat storage; the second molten salt valve and the ninth molten salt valve are opened, and the low-temperature molten salt in the second domain storage cavity enters the solar heat collector for preheating under the action of the molten salt pump; the preheated low-temperature molten salt enters the molten salt heater for further heating to obtain high-temperature molten salt; the high-temperature molten salt flows out of the molten salt heater and enters the first domain storage cavity; when the liquid level of the molten salt in the second domain storage cavity reaches the lowest operating liquid level, the second molten salt valve and the ninth molten salt valve are closed, and the low-temperature molten salt in the second domain storage cavity is stored in the first domain storage cavity after completing the heat storage; The third molten salt valve and the tenth molten salt valve are opened, the low-temperature molten salt in the three-domain storage cavity is preheated in the solar heat collector under the action of the molten salt pump, the preheated low-temperature molten salt is further heated in the molten salt heater, and high-temperature molten salt is obtained; the high-temperature molten salt flows out of the molten salt heater and enters the two-domain storage cavity, when the liquid level of the molten salt in the three-domain storage cavity reaches the minimum operating liquid level, the third molten salt valve and the tenth molten salt valve are closed, and the low-temperature molten salt in the three-domain storage cavity is stored in the two-domain storage cavity after completing heat storage; the fifth molten salt valve, the seventh molten salt valve and the molten salt pump are closed, and the heat storage is completed, at this time, the one-domain storage cavity, the two-domain storage cavity and the four-domain storage cavity of the molten salt storage tank store high-temperature molten salt, and the three-domain storage cavity stores a small amount of base salt; During heat release, the sixth molten salt valve, the eighth molten salt valve and the molten salt pump are in an open state, and the fifth molten salt valve and the seventh molten salt valve are in a closed state; the fourth molten salt valve and the eleventh molten salt valve are opened, the high-temperature molten salt in the four-domain storage cavity is heat-exchanged in the evaporator under the action of the molten salt pump, the low-temperature molten salt obtained by heat exchange flows back to the three-domain storage cavity, when the liquid level of the molten salt in the four-domain storage cavity reaches the minimum operating liquid level, the fourth molten salt valve and the eleventh molten salt valve are closed, and the high-temperature molten salt in the four-domain storage cavity is stored in the three-domain storage cavity after completing heat release; The first molten salt valve and the twelfth molten salt valve are opened, the high-temperature molten salt in the one-domain storage cavity is heat-exchanged in the evaporator under the action of the molten salt pump, the low-temperature molten salt obtained by heat exchange enters the four-domain storage cavity, when the liquid level of the molten salt in the one-domain storage cavity reaches the minimum operating liquid level, the first molten salt valve and the twelfth molten salt valve are closed, and the high-temperature molten salt in the one-domain storage cavity is stored in the four-domain storage cavity after completing heat exchange; the second molten salt valve and the ninth molten salt valve are opened, the high-temperature molten salt in the two-domain storage cavity is heat-exchanged in the evaporator under the action of the molten salt pump, the low-temperature molten salt obtained by heat exchange flows back to the one-domain storage cavity, when the liquid level of the molten salt in the two-domain storage cavity reaches the minimum operating liquid level, the second molten salt valve and the ninth molten salt valve are closed, and the high-temperature molten salt in the two-domain storage cavity is stored in the one-domain storage cavity after completing heat exchange; the sixth molten salt valve, the eighth molten salt valve and the molten salt pump are closed, and the heat release is completed, at this time, the one-domain storage cavity, the three-domain storage cavity and the four-domain storage cavity of the molten salt storage tank store low-temperature molten salt, and the two-domain storage cavity stores a small amount of base salt.

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