Multi-tank molten salt eutectic system and method

Abstract

The invention relates to the technical field of molten salt melting, and particularly discloses a multi-tank molten salt eutectic system and method.The multi-tank molten salt eutectic system comprises multiple sets of distributed salt melting units arranged side by side, and the output ends of the multiple sets of distributed salt melting units are jointly connected with a set of salt mixing tanks; the outlet of each group of distributed salt dissolving unit is connected with the inlet of the salt mixing tank, and the outlet of the salt mixing tank is provided with a fused salt conveying pump; each distributed salt dissolving unit is used for respectively melting the corresponding monomer molten salt into a liquid state and then synchronously conveying the molten salt to the salt mixing tank for eutectic. According to the distributed salt dissolving unit, various monomer molten salts can be melted into liquid and then synchronously enter the salt mixing tank for eutectic, and on the basis of independent melting to reduce impurities and avoid decomposition, eutectic of the molten salts can be better promoted and realized in the liquid state, so that the eutectic performance of the molten salts is improved. According to the method, the initial design parameters of the mixed molten salt after eutectic can be guaranteed to a greater extent with higher efficiency, and the subsequent stable operation of each molten salt project can be effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt melting, and more particularly to a multi-tank molten salt eutectic system and method. Background Art

[0002] Renewable energy sources such as photovoltaics, solar thermal power, wind power and hydropower are intermittent and unstable, which can easily cause a mismatch between energy supply and demand, and require the cooperation of energy storage technology. Molten salt heat storage is a relatively safe energy storage method. It uses molten salts such as nitrates as heat transfer media, and stores and releases energy through the heat storage and heat release cycle of molten salts to achieve effective energy migration; green electricity or valley electricity is used to heat molten salts and store them in high-temperature molten salt tanks. During the day, the high-temperature molten salt is extracted from the tank and heated through a molten salt heat exchanger to meet a variety of needs. The cooled molten salt after heat exchange flows into the low-temperature molten salt tank to complete the cycle; The initial salting is to melt the molten salt and realize eutectic according to a certain proportion of formula under fixed temperature conditions before the first use of molten salt. Whether the initial salting can control the molten salt eutectic is often the key to determining whether the molten salt used in the project can achieve its initial design parameters. By referring to the excellent and reasonable salting method to melt the solid salt into the tank, the temperature, enthalpy and other parameters of the molten salt designed for the project can be achieved. If the initial salting method is unreasonable, it will generally lead to problems such as lower temperature and reduced heat storage in the molten salt tank, which will seriously affect the later operation of the project. At present, the most widely used molten salts in the domestic market are binary salts and ternary salts, among which ternary salts are made by mixing KNO3, NaNO3 and NaNO2 in a certain proportion. In the traditional salt-making method, they are generally mixed on-site in proportion and placed in the salt-making system to melt, or compounded in proportion in advance and placed in the salt-making system to melt on-site; but in this salt-making method, a salt-making system cannot control the temperature alone. Due to the different physical properties of the three molten salts, it is easy to cause part of the molten salt to gasify, thereby changing the physical properties of the ternary salt described above; Specifically, KNO3 has a vaporization temperature of 400°C and a melting point of 334°C. After overheating, it decomposes to release oxygen and generates potassium nitrite. NaNO3 has a vaporization temperature of 380°C and a melting point of 307°C. After overheating, it decomposes to generate sodium nitrite. NaNO2 has a vaporization temperature of 320°C and a melting point of 276.9°C. After overheating, it decomposes to generate oxygen, nitrogen oxide and sodium oxide. Judging from the various temperature parameters of the above-mentioned ternary molten salt, the traditional rough salt-making method cannot well control the temperature in the same salt-making equipment. It is easy for one salt to melt while other molten salts have reached or exceeded the critical temperature of gasification and decomposition, which has a great impact on the physical properties of the batch of molten salt. Summary of the invention

[0003] In order to overcome the above technical problems, the present invention proposes a multi-tank molten salt eutectic system and method.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A multi-tank molten salt eutectic system comprises a plurality of distributed salt units arranged in parallel, wherein the output ends of the plurality of distributed salt units are commonly connected to a group of salt mixing tanks; The distributed salt unit comprises: A salt-forming tank, which is used to fill molten salt, wherein a stirring pump and a molten salt electric heater are installed in the salt-forming tank; A flow control valve is installed on the circulation pipeline of the salt tank to adjust the flow of molten salt; A natural gas molten salt furnace, which is used to preheat the molten salt, and a molten salt circulation pump is connected between the natural gas molten salt furnace and the salt tank; A cooler is arranged between the natural gas molten salt furnace and the salt melting tank and is used to supply cooling water; The outlet of each group of distributed salt units is connected to the inlet of the mixing salt tank, and a molten salt delivery pump is installed at the outlet of the mixing salt tank; each distributed salt unit melts the corresponding monomer molten salt into liquid state and then synchronously delivers it to the mixing salt tank for eutectic.

[0005] As a further solution of the present invention: the distributed salt-forming unit also includes a compressed carbon dioxide heat pump, and a heat exchanger is arranged between the compressed carbon dioxide heat pump and the salt-forming tank.

[0006] As a further solution of the present invention: the salt mixing tank comprises a tank body, a plurality of liquid inlet pipes connected to corresponding distributed salt units are arranged at the inlet of the tank body, and a liquid discharge pipe is arranged at the outlet of the tank body; an outer jacket and an inner jacket are arranged in the tank body, respectively, a heat-insulating interlayer is formed between the outer jacket and the tank body, a mixing flow chamber is formed between the outer jacket and the inner jacket, the upper end of the mixing flow chamber is open, and the lower end is connected to the inside of the inner jacket, a spiral mixing flow plate is arranged in the mixing flow chamber, and an electric heating plate is pre-buried in the spiral mixing flow plate; A driving motor is installed on the top of the tank body, and the output end of the driving motor is connected to a hollow rotating shaft extending into the inner jacket, and a stirring blade is installed at the bottom of the hollow rotating shaft; a spoiler is arranged in the inner jacket so as to be liftable, and the spoiler is used to lift the liquid salt at the bottom of the inner jacket to the top of the inner jacket and discharge it into the mixing flow chamber on the outside.

[0007] As a further solution of the present invention: an inverted cone flow partition is arranged on the top of the tank body, the opening diameter of the lower end of the inverted cone flow partition is smaller than the opening diameter of the upper end of the inner jacket, and the opening height of the lower end of the inverted cone flow partition is higher than the opening height of the upper end of the inner jacket.

[0008] As a further solution of the present invention: the spoiler comprises an annular support frame fixed on the inverted conical flow partition and a lifting plate located below the annular support frame, a plurality of guide rods are vertically fixed on the lifting plate, and the guide rods are slidably arranged on the annular support frame; the middle part of the lifting plate is sleeved on the hollow rotating shaft, and the hollow rotating shaft is provided with an external thread adapted to the lifting plate; As a further solution of the present invention: an annular enclosure is arranged on the outer side of the lifting plate and is slidably fitted with the inner wall of the inner jacket, and a plurality of drain ports are opened circumferentially on the annular enclosure; a plurality of stepped grooves are opened circumferentially on the bottom surface of the lifting plate, and a one-way sealing plate is hinged in the stepped groove by a hinge.

[0009] As a further solution of the present invention: an infusion cavity is vertically opened in the hollow rotating shaft, the upper end of the infusion cavity is connected with the drainage tube, a liquid extraction head is installed at the lower end of the hollow rotating shaft, the interior of the liquid extraction head is connected with the lower end of the infusion cavity, and a plurality of first through holes are opened circumferentially on the outer side of the liquid extraction head.

[0010] As a further solution of the present invention: a sealing sleeve is fixedly installed in the top of the tank body, the sealing sleeve is sleeved on the outside of the hollow rotating shaft, a sealing ring is installed at the rotational connection between the sealing sleeve and the hollow rotating shaft, a plurality of second through holes are opened circumferentially on the hollow rotating shaft, the second through holes connect the infusion cavity with the inside of the sealing sleeve, and the sealing sleeve is connected to the drainage tube.

[0011] As a further solution of the present invention: a separator is provided at the connection point between the mixed flow chamber and the inner jacket, and the separator includes a rotating disk, which is fixedly connected to the hollow rotating shaft through a connecting rod, and the rotating disk is rotatably installed at the connection point between the mixed flow chamber and the inner jacket, and a plurality of filter screens are circumferentially arranged on the rotating disk, and a paddle extending into the mixed flow chamber is provided between adjacent filter screens.

[0012] As a further solution of the present invention: a mounting block is provided at the bottom outlet of the spiral mixing plate, the mounting block is fixed on the outer wall of the inner jacket, a number of spoilers are symmetrically provided on both sides of the mounting block, and multiple groups of spoilers are arranged in an array along the vertical direction, and the length of the spoilers increases successively from top to bottom.

[0013] The present invention also discloses a multi-tank molten salt eutectic method, comprising the following steps: S1. Melt the molten salt in the initial tank and preheat the mixed salt tank. Adjust the flow regulating valve to the self-circulating state of the salt-forming unit, and fill the corresponding solid molten salt into the salt-forming tank of each distributed salt-forming unit. After the salt-forming tank is full, turn on the molten salt electric heater to melt the molten salt in the initial tank separately. S2, start the natural gas molten salt furnace for preheating, start the molten salt circulation pump, and realize the self-circulation of the salt tank and the natural gas molten salt furnace; S3, let it stand and start the stirring pump; S4, adjust the flow control valve to realize the self-circulation of each distributed salt unit and the delivery of liquid salt to the salt mixing tank at the same time; when the liquid molten salt level in each salt tank drops to the mark line in the tank, start feeding solid salt; S5. After the preheating of the mixing salt tank is completed, the preheating system is removed and the built-in heating of the mixing salt tank is turned on; when the liquid salt level reaches one-half of the volume of the mixing salt tank, the molten salt delivery pump is turned on to deliver molten salt to the low-temperature molten salt tank.

[0014] Beneficial effects of the present invention: (1) Melt the molten salts separately to ensure that different molten salts melt in a reasonable temperature range The multiple groups of distributed salt-forming units A, B, C, etc. provided in the present invention can be designed and adjusted to adjust the melting temperature of the molten salt according to the fixed physical property parameters of different molten salts, thereby avoiding the decomposition of part of the molten salt due to excessive temperature and the like caused by the mixed melting of multiple salts in the traditional single-tank salt-forming method, and effectively ensuring the purity of various monomer molten salts and reducing impurities after melting.

[0015] (2) Liquid eutectic The distributed salt unit in the present invention can realize that various types of monomer molten salts are melted to liquid and then enter the mixed salt tank for eutectic simultaneously. On the basis of separate melting to reduce impurities and avoid decomposition, in the liquid state, it can better promote and realize the eutectic of molten salt, and can more efficiently and to a greater extent guarantee the initial design parameters of the mixed molten salt after eutectic, and can effectively guarantee the subsequent stable operation of various molten salt projects.

[0016] (3) High stability The heat source of the present invention is configured with a natural gas molten salt furnace and a compressed carbon dioxide heat pump, which serve as backup for each other; at the same time, multiple sets of distributed salt-forming units A, B, and C are arranged, which also have a backup relationship. Compared with the traditional single-tank salt-forming system, the present invention is more stable.

[0017] (4) High security In the present invention, each monomer molten salt is melted separately and is not mixed with other molten salts, so it is more difficult to contact other impurities, and there is no danger of nitrate contacting other substances; at the same time, the multi-tank monomer salting of the present invention can also avoid confusion and errors in the proportions of various molten salts in the salting operation, and the system is safe and stable, the technology is mature, and the safety is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a structural schematic diagram of a multi-tank molten salt eutectic system of the present invention; Figure 2 It is a three-dimensional schematic diagram of the salt mixing tank in the present invention; Figure 3 It is a cross-sectional view of the salt mixing tank in the present invention; Figure 4 It is a schematic diagram of the structure of the spoiler and the separator in the present invention; Figure 5 It is a cross-sectional view of the salt mixing tank in the present invention from another perspective; Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 for Figure 5 Enlarged view of point B in the middle; Figure 8 for Figure 5 Enlarged view of point C in the middle; Fig. 9 It is a cross-sectional view of the tank body and the outer jacket in the present invention; Fig.10 for Fig. 9 Enlarged view of point D in the middle.

[0020] In the figure: 1. Compressed carbon dioxide heat pump; 2. Natural gas molten salt furnace; 3. Cooler; 4. Salt tank; 5. Heat exchanger; 6. Molten salt circulation pump; 7. Flow control valve; 8. Stirring pump; 9. Molten salt electric heater; 10. Molten salt delivery pump; 11. Mixing salt tank; 1100. Tank body; 1101. Liquid inlet pipe; 1102. Liquid discharge pipe; 1103. Insulation interlayer; 1110. Driving motor; 1120. Outer jacket; 1130. Inner jacket; 1131. Mounting block; 1132. Spoiler; 1140. Spiral mixing plate; 1141. Electric heating plate; 1150. Inverted cone flow partition; 1160 , hollow shaft; 1161, external thread; 1162, liquid extraction head; 1163, infusion cavity; 1164, first through hole; 1165, sealing sleeve; 1166, sealing ring; 1167, second through hole; 1170, stirring blade; 1180, spoiler; 1181, annular support frame; 1182, lifting plate; 1183, guide rod; 1184, annular enclosure; 1185, drain port; 1186, stepped groove; 1187, one-way sealing plate; 1188, hinge; 1190, separator; 1191, connecting rod; 1192, rotating disk; 1193, filter screen; 1194, dial plate. DETAILED DESCRIPTION

[0021] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0022] See also Figure 1 The present invention discloses a multi-tank molten salt eutectic system, comprising a plurality of distributed eutectic units arranged in parallel (including but not limited to Figure 1 The output ends of the multiple distributed salt units are connected to a group of salt mixing tanks 11; The distributed salt unit includes a natural gas molten salt furnace 2, a cooler 3, a salt tank 4, a molten salt circulation pump 6, a flow regulating valve 7, a stirring pump 8 and a molten salt electric heater 9; the salt tank 4 is used to fill molten salt, and the stirring pump 8 and the molten salt electric heater 9 are installed in the salt tank 4; the flow regulating valve 7 is installed on the circulation pipeline of the salt tank 4, and is used to adjust the molten salt flow; the natural gas molten salt furnace 2 is used to preheat the molten salt, and a molten salt circulation pump 6 is connected between the natural gas molten salt furnace 2 and the salt tank 4; the cooler 3 is arranged between the natural gas molten salt furnace 2 and the salt tank 4, and is used to supply cooling water; The outlet of each group of distributed salt units is connected to the inlet of the salt mixing tank 11, and a molten salt delivery pump 10 is installed at the outlet of the salt mixing tank 11; each distributed salt unit melts the corresponding monomer molten salt into liquid state and then synchronously delivers it to the salt mixing tank 11 for eutectic.

[0023] For further information, see Figure 1 The distributed desalination unit also includes a compressed carbon dioxide heat pump 1, and a heat exchanger 5 is arranged between the compressed carbon dioxide heat pump 1 and the desalination tank 4; the compressed carbon dioxide heat pump 1 can be used as a backup heat source, and can also be used as a main heat source in application scenarios without natural gas.

[0024] Specifically, taking the initial salt treatment of molten salt as an application scenario and binary molten salt as an example, the system workflow is explained: At present, the most mature binary molten salt used in domestic solar thermal power generation applications is composed of NaNO3 (60%) and KNO3 (40%), of which NaNO3 has a gasification temperature of 380°C and a melting point of 307°C, and KNO3 has a gasification temperature of 400°C and a melting point of 334°C. Before the salting work begins, the salting system A is randomly assigned to be the NaNO3 salting unit and the salting system B is randomly assigned to be the KNO3 salting unit.

[0025] After the salting work starts, the A unit and the B unit start to operate synchronously, and the solid molten salt is fed according to the predetermined ratio of 6:4, and it is ensured that the molten salt enters the salt mixing tank 11 synchronously in the state of liquid salt at the ratio of 6:4.

[0026] Take the NaNO3 salt unit in unit A as an example to explain the workflow: S1, melt the molten salt in the initial tank and preheat the salt mixing tank 11, adjust the flow regulating valve 7 to the self-circulating state of the salt, fill the solid molten salt into the salt tank 4, and after the salt tank 4 is filled, turn on the molten salt electric heater 9 to melt the molten salt in the initial tank; It should be noted that the preheating process of the salt mixing tank 11 described in step S1 requires a storage tank preheating system, which is not elaborated in the present invention; in addition, after 48 hours, all the molten salt in the initial tank is melted into liquid, with a temperature of about 330°C and a mass of about 30t; within the 48 hours, it is necessary to continuously observe the drop in the highest top surface of the solid salt in the salt tank 4, and replenish the solid salt at any time; S2, start the natural gas molten salt furnace 2 for preheating. When the temperature in the natural gas molten salt furnace 2 reaches 330°C, start the molten salt circulation pump 6 to realize the self-circulation of the salt tank 4 and the natural gas molten salt furnace 2; S3, let it stand, raise the temperature of the natural gas molten salt furnace 2 to 350°C, and start the stirring pump 8; S4. When the temperature in the salt-forming tank 4 rises to 350°C, the flow regulating valve 7 is adjusted to realize the self-circulation of the system and the simultaneous delivery of liquid salt to the salt mixing tank 11; when the liquid molten salt level in the salt-forming tank 4 drops to the marking line in the tank (about 1 / 2), the solid salt feeding is started.

[0027] It should be noted that, during step S4, the flow rate of the flow regulating valve 7 is continuously adjusted according to the flow rate requirements of each salt-making project, usually 30 t / h for all molten salts, which is calculated according to the system of the present invention, i.e., 18 t / h for NaNO3 and 12 t / h for KNO3; at this point, the salt-making work can be stably carried out at a solid salt feeding speed of 18 t / h.

[0028] Following the same operation as above, the KNO3 salt-making unit of unit B is subjected to salt-making work.

[0029] It should be noted that the gasification temperature of KNO3 in unit B is 400℃, the melting point is 334℃, the temperature of the initial tank molten salt is controlled at 360℃, and the final setting temperature of the natural gas molten salt furnace shall not exceed 380℃; the solid salt feeding rate of the system is 12t / h.

[0030] After the preheating of the salt mixing tank 11 is completed, the preheating temperature should be 360±5°C. When the liquid salt enters 60cm above the molten salt electric heater 9 in the salt mixing tank 11, the preheating system is removed, and the molten salt electric heater 9 installed in the salt mixing tank 11 is turned on. The heating temperature is set to 360±5°C to maintain the temperature in the tank; When the liquid salt level reaches one-half of the volume of the salt mixing tank 11, the molten salt delivery pump 10 is turned on to deliver molten salt to the low-temperature molten salt tank in the project, and the molten salt delivery flow rate is 30t / h.

[0031] In summary, the multi-tank molten salt eutectic system of the present invention can enter a normal working state based on the conditions of a final molten salt rate of 30 t / h, 360°C cold tank entry, etc.

[0032] In one embodiment, considering that the multi-component molten salts simultaneously enter the mixing salt tank 11 for eutectic formation, the multi-component molten salts are not fully mixed, which may lead to uneven distribution of components. In addition, different molten salts or molten salts at different temperatures have different densities, which leads to changes in the viscosity and fluidity of the molten salts in local areas, thereby causing stratification. In view of the above problems, it is necessary to improve the structure of the mixing salt tank 11.

[0033] See also Figure 2 and Figure 3 The salt mixing tank 11 comprises a tank body 1100, wherein a plurality of liquid inlet pipes 1101 connected to corresponding distributed salt units are arranged at the inlet of the tank body 1100, and a liquid discharge pipe 1102 is arranged at the outlet of the tank body 1100; an outer jacket 1120 and an inner jacket 1130 are arranged in the tank body 1100, respectively, a heat-insulating interlayer 1103 is formed between the outer jacket 1120 and the tank body 1100, a mixing flow cavity is formed between the outer jacket 1120 and the inner jacket 1130, the upper end of the mixing flow cavity is open, and the lower end is connected to the inside of the inner jacket 1130, a spiral mixing flow plate 1140 is arranged in the mixing flow cavity, and an electric heating plate 1141 is pre-buried in the spiral mixing flow plate 1140; A driving motor 1110 is installed on the top of the tank body 1100, and a hollow rotating shaft 1160 extending into the inner jacket 1130 is connected to the output end of the driving motor 1110, and a stirring blade 1170 is installed at the bottom of the hollow rotating shaft 1160; a spoiler 1180 is arranged in the inner jacket 1130 so as to be liftable, and the spoiler 1180 is used to lift the liquid salt at the bottom of the inner jacket 1130 to the top of the inner jacket 1130 and discharge it into the outer mixing chamber; Specifically, the liquid salt in each distributed salt unit is simultaneously injected into the inner jacket 1130 of the tank body 1100 through the corresponding liquid inlet pipe 1101, and the stirring blade 1170 at the bottom of the hollow rotating shaft 1160 is driven by the driving motor 1110 to rotate, so as to stir the multi-component liquid salt mixed in the inner jacket 1130; during the continuous feeding process, the multi-component liquid salt at the bottom of the inner jacket 1130 is periodically lifted upward by the spoiler 1180, so that the multi-component liquid salt at different levels is further mixed until the multi-component liquid salt is stirred. The elementary liquid salt reaches the opening at the upper end of the inner jacket 1130, and flows radially outward into the mixing chamber, and the multi-component liquid salt flows downward in a spiral along the spiral mixing plate 1140. At the same time, the electric heating plate 1141 in the spiral mixing plate 1140 heats the multi-component liquid salt to promote the melting and fusion of the multi-component liquid salt. Subsequently, the fully fused multi-component liquid salt flows back to the inner jacket 1130 from the bottom of the mixing chamber; this process is repeated to achieve turbulence, mixing and fusion of the multi-component liquid salt, thereby effectively preventing the liquid salt from stratifying.

[0034] For further information, see Figure 3 In order to prevent the liquid salt injected by the liquid inlet pipe 1101 from impacting and interfering with the liquid salt lifted upward by the spoiler 1180, an inverted cone flow partition 1150 is provided on the top of the tank body 1100, and the opening diameter of the lower end of the inverted cone flow partition 1150 is smaller than the opening diameter of the upper end of the inner jacket 1130, and the opening height of the lower end of the inverted cone flow partition 1150 is higher than the opening height of the upper end of the inner jacket 1130; The liquid salt injected from the liquid inlet pipe 1101 is guided by the inverted cone flow partition 1150 so that the liquid salt at the outlet of the liquid inlet pipe 1101 can be accurately put into the inner jacket 1130, thereby not mixing with the multi-component liquid salt in the mixing chamber.

[0035] See also Figure 4 The spoiler 1180 includes an annular support frame 1181 fixed on the inverted cone-shaped flow partition 1150 and a lifting plate 1182 located below the annular support frame 1181, a plurality of guide rods 1183 are vertically fixed on the lifting plate 1182, and the guide rods 1183 are slidably arranged on the annular support frame 1181; the middle part of the lifting plate 1182 is sleeved on the hollow rotating shaft 1160, and the hollow rotating shaft 1160 is provided with an external thread 1161 adapted to the lifting plate 1182; the outer side of the lifting plate 1182 is provided with an annular enclosure 1184 that is slidably fitted with the inner wall of the inner jacket 1130, and the annular enclosure 1184 is provided with a plurality of drain ports 1185 on the circumferential direction; See also Figure 5 and Figure 6 The bottom surface of the lifting plate 1182 is provided with a plurality of stepped grooves 1186 in the circumferential direction, and a one-way sealing plate 1187 is hingedly connected in the stepped groove 1186 via a hinge 1188; Specifically, when the driving motor 1110 drives the hollow shaft 1160 to rotate forward, the hollow shaft 1160 is threadedly connected to the lifting plate 1182, thereby driving the lifting plate 1182 to rise vertically along the inner jacket 1130, and at the same time, the guide rod 1183 slides upward relative to the annular support frame 1181. At this time, the one-way sealing plate 1187 is in a closed state, and the multi-component liquid salt at the bottom of the inner jacket 1130 is lifted upward by the lifting plate 1182 until the lifting plate 1182 reaches the upper opening of the inner jacket 1130, and the multi-component liquid salt in the lifting plate 1182 flows outward from each drain port 1185 into the mixed flow chamber; When the driving motor 1110 drives the hollow rotating shaft 1160 to reverse, it drives the lifting plate 1182 to vertically descend along the inner jacket 1130. At this time, the one-way sealing plate 1187 flips upward and opens under the fluid impact of the liquid salt, so that the multi-component liquid salt at the bottom of the inner jacket 1130 flows upward through the stepped groove 1186 to the top of the lifting plate 1182, thereby achieving the capture of the multi-component liquid salt at the bottom of the inner jacket 1130; then the hollow rotating shaft 1160 rotates forward again to drive the lifting plate 1182 to rise, and this cycle is repeated to achieve the repeated turbulence operation of the multi-component liquid salt.

[0036] Regarding the discharge process of the multi-liquid salt in the salt mixing tank 11, due to the structural limitations of the stirring blades 1170 and the spoiler 1180 in the inner jacket 1130, the drain pipe 1102 cannot be directly inserted into the bottom of the inner jacket 1130. Therefore, in this embodiment, the hollow shaft 1160 is used for draining. For details, please refer to Figure 5 and Figure 7 The hollow shaft 1160 has an infusion cavity 1163 vertically formed therein, the upper end of the infusion cavity 1163 is connected to the drainage tube 1102, a liquid extraction head 1162 is installed at the lower end of the hollow shaft 1160, the interior of the liquid extraction head 1162 is connected to the lower end of the infusion cavity 1163, and a plurality of first through holes 1164 are formed circumferentially on the outer side of the liquid extraction head 1162; When the molten salt delivery pump 10 is turned on, the multi-component liquid salt at the bottom of the inner jacket 1130 can enter the infusion cavity 1163 through the first through hole 1164 and then enter the drainage pipe 1102 .

[0037] Considering that after the driving motor 1110 is started, the hollow shaft 1160 is in a continuous rotating state, in order to facilitate the liquid salt in the infusion cavity 1163 of the hollow shaft 1160 to smoothly transfer to the drainage tube 1102, please refer to Figure 5 and Figure 8A sealing sleeve 1165 is fixedly installed on the top of the tank body 1100, and the sealing sleeve 1165 is sleeved on the outside of the hollow shaft 1160. A sealing ring 1166 is installed at the rotation connection between the sealing sleeve 1165 and the hollow shaft 1160. A plurality of second through holes 1167 are opened circumferentially on the hollow shaft 1160. The second through holes 1167 connect the infusion cavity 1163 with the inside of the sealing sleeve 1165, and the sealing sleeve 1165 is connected with the drainage tube 1102; Specifically, no matter the hollow rotating shaft 1160 is in a stationary state or in a forward or reverse rotation state, the liquid salt in the infusion cavity 1163 can flow into the sealing sleeve 1165 through the second through hole 1167, and then the liquid salt in the sealing sleeve 1165 flows into the discharge tube 1102, thereby not affecting the continuous discharge of the liquid salt and ensuring the stability of the liquid salt discharge flow rate.

[0038] For further information, see Figure 3 and Figure 4 Considering that part of the crystals and impurities will be precipitated from the multi-component liquid salt during the eutectic process, in order to facilitate the use of these part of the crystals and impurities to improve the quality of the liquid salt at the end of the discharge pipe 1102, a separator 1190 is provided at the connection between the mixing chamber and the inner jacket 1130. The separator 1190 includes a rotating disk 1192, which is fixedly connected to the hollow rotating shaft 1160 through a connecting rod 1191. The rotating disk 1192 is rotatably installed at the connection between the mixing chamber and the inner jacket 1130. A plurality of filter screens 1193 are circumferentially provided on the rotating disk 1192, and a paddle 1194 extending into the mixing chamber is provided between adjacent filter screens 1193. The crystals and impurities precipitated in the mixed flow chamber are intercepted by the filter 1193, so as to prevent the crystals and impurities from flowing back into the inner jacket 1130 again, so as to achieve the separation of the crystals and impurities; when the hollow shaft 1160 rotates, it can drive the rotating disk 1192 to rotate synchronously, thereby driving the paddle 1194 to rotate circumferentially, so as to circumferentially paddle and divert the multi-component liquid salt in the mixed flow chamber, so that the multi-component liquid salt is mixed more evenly, and at the same time, the multi-component liquid salt is quickly distributed around the rotating disk 1192, so that the multi-component liquid salt can quickly flow back into the inner jacket 1130 through the filter 1193 around it.

[0039] Also, see Fig. 9 and Fig.10, since the point where the multi-liquid salt falls from the bottom outlet of the spiral mixing plate 1140 to the bottom of the mixing chamber is fixed, it is easy to cause the liquid salt to accumulate at this point. For this reason, a mounting block 1131 is provided at the bottom outlet of the spiral mixing plate 1140, and the mounting block 1131 is fixed on the outer wall of the inner jacket 1130. A plurality of spoilers 1132 are symmetrically provided on both sides of the mounting block 1131. The plurality of groups of spoilers 1132 are arranged in an array in the vertical direction, and the lengths of the spoilers 1132 increase from top to bottom. When the multi-component liquid salt falls from the bottom outlet of the spiral mixing plate 1140, it will hit the spoiler plates 1132 in sequence. After hitting the upper spoiler plate 1132, the liquid salt will fall onto the lower spoiler plate 1132, and then continue to hit it and fall down again. This process is repeated many times, and the liquid salt can be mixed and dispersed at multiple levels, further avoiding stratification and accumulation of the multi-component liquid salt.

[0040] The specific implementation methods of this embodiment are described above, but this embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms inspired by this embodiment, all of which are within the protection of this embodiment.

Claims

1. A multi-tank molten salt eutectic system, characterized in that: It comprises a plurality of distributed salt units arranged in parallel, wherein the output ends of the plurality of distributed salt units are commonly connected to a group of salt mixing tanks (11); The distributed salt unit comprises: A salt-forming tank (4) for filling molten salt, wherein a stirring pump (8) and a molten salt electric heater (9) are installed in the salt-forming tank (4); A flow regulating valve (7) installed on the circulation pipeline of the salt tank (4) and used to regulate the flow of molten salt; A natural gas molten salt furnace (2) for preheating molten salt, wherein a molten salt circulation pump (6) is connected between the natural gas molten salt furnace (2) and the salt tank (4); A cooler (3) is arranged between the natural gas molten salt furnace (2) and the salt melting tank (4) and is used to supply cooling water; The outlet of each group of distributed salt units is connected to the inlet of a salt mixing tank (11), and a molten salt delivery pump (10) is installed at the outlet of the salt mixing tank (11); each distributed salt unit melts the corresponding monomer molten salt into a liquid state and then synchronously delivers it to the salt mixing tank (11) for eutectic formation.

2. A multi-tank molten salt eutectic system according to claim 1, characterized in that: The distributed salt-removing unit further comprises a compressed carbon dioxide heat pump (1), and a heat exchanger (5) is provided between the compressed carbon dioxide heat pump (1) and the salt-removing tank (4).

3. A multi-tank molten salt eutectic system according to claim 1, characterized in that: The salt mixing tank (11) comprises a tank body (1100), wherein a plurality of liquid inlet pipes (1101) connected to corresponding distributed salt units are arranged at the inlet of the tank body (1100), and a liquid discharge pipe (1102) is arranged at the outlet of the tank body (1100); an outer jacket (1120) and an inner jacket (1130) are arranged in the tank body (1100), a heat-insulating interlayer (1103) is formed between the outer jacket (1120) and the tank body (1100), and a mixing chamber is formed between the outer jacket (1120) and the inner jacket (1130), wherein the upper end of the mixing chamber is open and the lower end is connected to the interior of the inner jacket (1130), and a spiral mixing plate (1140) is arranged in the mixing chamber, and an electric heating plate (1141) is pre-buried in the spiral mixing plate (1140); A driving motor (1110) is installed on the top of the tank body (1100); the output end of the driving motor (1110) is connected to a hollow rotating shaft (1160) extending into the inner jacket (1130); a stirring blade (1170) is installed at the bottom of the hollow rotating shaft (1160); a spoiler (1180) is arranged in a liftable manner in the inner jacket (1130); the spoiler (1180) is used to lift the liquid salt at the bottom of the inner jacket (1130) to the top of the inner jacket (1130) and discharge it into the outer mixing chamber.

4. A multi-tank molten salt eutectic system according to claim 3, characterized in that: An inverted cone-shaped flow partition (1150) is arranged at the top of the tank body (1100), the opening diameter of the lower end of the inverted cone-shaped flow partition (1150) is smaller than the opening diameter of the upper end of the inner jacket (1130), and the opening height of the lower end of the inverted cone-shaped flow partition (1150) is higher than the opening height of the upper end of the inner jacket (1130).

5. A multi-tank molten salt eutectic system according to claim 4, characterized in that: The spoiler (1180) comprises an annular support frame (1181) fixed on the inverted cone-shaped flow partition (1150) and a lifting plate (1182) located below the annular support frame (1181); a plurality of guide rods (1183) are vertically fixed on the lifting plate (1182); the guide rods (1183) are slidably arranged on the annular support frame (1181); the middle part of the lifting plate (1182) is sleeved on the hollow rotating shaft (1160); the hollow rotating shaft (1160) is provided with an external thread (1161) adapted to the lifting plate (1182); The outer side of the lifting plate (1182) is provided with an annular enclosure (1184) which is slidably fitted with the inner wall of the inner jacket (1130), and the annular enclosure (1184) is circumferentially provided with a plurality of drain ports (1185); the bottom surface of the lifting plate (1182) is circumferentially provided with a plurality of stepped grooves (1186), and a one-way sealing plate (1187) is hingedly connected in the stepped groove (1186) via a hinge (1188).

6. A multi-tank molten salt eutectic system according to claim 3, characterized in that: An infusion cavity (1163) is vertically opened in the hollow rotating shaft (1160), and the upper end of the infusion cavity (1163) is connected to the drainage tube (1102). A liquid extraction head (1162) is installed at the lower end of the hollow rotating shaft (1160), and the interior of the liquid extraction head (1162) is connected to the lower end of the infusion cavity (1163). A plurality of first through holes (1164) are circumferentially opened on the outer side of the liquid extraction head (1162).

7. A multi-tank molten salt eutectic system according to claim 6, characterized in that: A sealing sleeve (1165) is fixedly installed at the top of the tank body (1100). The sealing sleeve (1165) is sleeved on the outside of the hollow rotating shaft (1160). A sealing ring (1166) is installed at the rotational connection between the sealing sleeve (1165) and the hollow rotating shaft (1160). A plurality of second through holes (1167) are opened circumferentially on the hollow rotating shaft (1160). The second through holes (1167) connect the infusion cavity (1163) with the inside of the sealing sleeve (1165). The sealing sleeve (1165) is connected to the drainage tube (1102).

8. A multi-tank molten salt eutectic system according to claim 3, characterized in that: A separator (1190) is provided at the connection point between the mixed flow chamber and the inner jacket (1130), and the separator (1190) comprises a rotating disk (1192). The rotating disk (1192) is fixedly connected to the hollow rotating shaft (1160) via a connecting rod (1191), and the rotating disk (1192) is rotatably installed at the connection point between the mixed flow chamber and the inner jacket (1130). A plurality of filter screens (1193) are circumferentially provided on the rotating disk (1192), and a paddle (1194) extending into the mixed flow chamber is provided between adjacent filter screens (1193).

9. A multi-tank molten salt eutectic system according to claim 8, characterized in that: A mounting block (1131) is provided at the bottom outlet of the spiral mixing plate (1140), and the mounting block (1131) is fixed on the outer wall of the inner jacket (1130). A plurality of spoiler plates (1132) are symmetrically provided on both sides of the mounting block (1131), and a plurality of groups of spoiler plates (1132) are arranged in an array along the vertical direction, and the lengths of the spoiler plates (1132) increase sequentially from top to bottom.

10. A method for using the multi-tank molten salt eutectic system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, melting the molten salt in the primary tank and preheating the salt mixing tank (11), adjusting the flow control valve (7) to the self-circulating state of salting, filling the corresponding solid molten salt into the salting tank (4) of each distributed salting unit, and after the salting tank (4) is filled, turning on the molten salt electric heater (9) to melt the molten salt in the primary tank respectively; S2, starting the natural gas molten salt furnace (2) for preheating, and starting the molten salt circulation pump (6) to achieve self-circulation of the salt tank (4) and the natural gas molten salt furnace (2); S3, let it stand, and start the stirring pump (8); S4, adjusting the flow control valve (7) to realize the self-circulation of each distributed salt-forming unit and the simultaneous delivery of liquid salt to the salt mixing tank (11); when the liquid molten salt level in each salt-forming tank (4) drops to the marking line in the tank, solid salt feeding begins; S5. When the preheating of the salt mixing tank (11) is completed, the preheating system is removed and the internal heating of the salt mixing tank (11) is turned on; when the liquid salt level reaches half of the volume of the salt mixing tank (11), the molten salt delivery pump (10) is turned on to deliver molten salt to the low-temperature molten salt tank.

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