Molten salt storage tank system and operation method thereof

Abstract

The invention discloses a molten salt storage tank system which comprises a molten salt mother tank and further comprises a master control system, the molten salt mother tank comprises a hot molten salt mother tank and a cold molten salt mother tank, a gas pressure stabilizing tank is arranged between the hot molten salt mother tank and the cold molten salt mother tank, and a gas compressor is arranged on the gas pressure stabilizing tank; radar liquid level meters, safety valves and communicating pipes are arranged at the tops of the hot molten salt mother tank and the cold molten salt mother tank, anti-condensation electric heaters are arranged at the bottoms of the hot molten salt mother tank and the cold molten salt mother tank, and the ends A of the communicating pipes of the hot molten salt mother tank and the cold molten salt mother tank penetrate through the hot molten salt mother tank and the cold molten salt mother tank correspondingly; the master control system is connected with the radar liquid level meter, the safety valve, the gas surge tank and the gas compressor. The invention further provides an operation method of the system. The problems of vibration, deformation and the like of the long-shaft pump are solved, the molten salt storage tank can adopt a large height-diameter ratio, the occupied area is reduced, meanwhile, the ineffective salt amount is reduced, and the investment cost is saved.

Description

Technical Field

[0001] The invention relates to a molten salt storage tank system and an operation method thereof, belonging to the technical field of molten salt storage tanks. Background Art

[0002] Molten salt energy storage technology has great advantages in the field of large-capacity and long-term energy storage. The amount of molten salt required for peak-shaving of solar thermal power stations and thermal power molten salt energy storage is relatively large. Due to the limitations of molten salt pump technology, the height of molten salt storage tanks is generally less than 20 meters.

[0003] The current molten salt storage tank system has the following problems:

[0004] (1) The bottom of the molten salt storage tank is welded from steel plates of different shapes and thicknesses. Due to deviations in processing and welding techniques, thermal stress concentration will occur after the tank is filled with hot molten salt. Severe thermal stress concentration will cause the molten salt tank to crack and leak molten salt. This is the main reason for the leakage of the molten salt storage tank. The larger the diameter of the molten salt storage tank, the more prominent the thermal stress concentration phenomenon.

[0005] (2) There is a certain safety distance between the inlet of the molten salt pump and the bottom of the molten salt storage tank. The distance is generally 0.5 meters for large molten salt storage tanks. The salt in this part is invalid salt. The smaller the height-to-diameter ratio of the molten salt storage tank, the greater the proportion of invalid salt.

[0006] (3) The molten salt pump is generally of VS1 or VS4 structure, and the length of the pump shaft matches the height of the molten salt tank. At present, the pump shaft length used in large-scale molten salt projects in China is about 14 to 17 meters. If the pump shaft is too long, there will be problems such as insufficient shaft rigidity, large deflection, and poor shaft straightness. From the operation of the long-shaft molten salt pump in the solar thermal power station, various problems such as large vibration occurred during operation, and some even failed to operate from the beginning of installation, which is related to the length of the pump shaft. In addition, the manufacturing cost of the long-shaft pump is high. The price of the long-shaft pump with the same flow rate and head is more than 1 times that of the short-shaft pump. Summary of the invention

[0007] The purpose of the present invention is to provide a molten salt storage tank system. The present invention also provides an operation method of the molten salt storage tank system. The present invention solves the problems of vibration and deformation of the long-axis pump. The molten salt storage tank can adopt a large aspect ratio to reduce the floor space of the molten salt storage tank, while reducing the amount of invalid salt and saving investment costs.

[0008] To solve the above technical problems, the present invention adopts the following technical scheme: a molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system, the molten salt mother tank comprising a hot molten salt mother tank and a cold molten salt mother tank, a gas pressure regulating tank is arranged between the hot molten salt mother tank and the cold molten salt mother tank, a compressor is arranged on the gas pressure regulating tank, radar level gauges, safety valves and connecting pipes are arranged on the tops of the hot molten salt mother tank and the cold molten salt mother tank, anti-condensation electric heaters are arranged on the bottoms of the hot molten salt mother tank and the cold molten salt mother tank, the connecting pipe comprises an A end and a B end, the A end of the connecting pipe of the hot molten salt mother tank and the cold molten salt mother tank respectively passes through the hot molten salt mother tank and the cold molten salt mother tank, and the general control system is respectively connected to the radar level gauge, the safety valve, the gas pressure regulating tank and the compressor.

[0009] The aforementioned molten salt storage tank system, the B end of the connecting pipe on the hot molten salt mother tank is connected to the hot molten salt sub-tank, the height of the hot molten salt sub-tank is lower than the bottom height of the hot molten salt mother tank, and the hot molten salt mother tank and the hot molten salt sub-tank are connected to the salt draining tank.

[0010] The aforementioned molten salt storage tank system, the B end of the connecting pipe on the cold molten salt mother tank is connected to the cold molten salt sub-tank, the height of the cold molten salt sub-tank is lower than the bottom height of the cold molten salt mother tank, the cold molten salt mother tank, the cold molten salt mother tank and the cold molten salt sub-tank are also respectively connected to the salt diversion tank, a salt diversion pump is arranged on the salt diversion tank, and salt diversion valves are arranged between the hot molten salt sub-tank and the cold molten salt sub-tank and the salt diversion tank, and the overall control system is respectively connected to the salt diversion pump and the salt diversion valve.

[0011] In the aforementioned molten salt storage tank system, the hot molten salt sub-tank and the cold molten salt sub-tank are both provided with sub-tank level gauges and molten salt pumps, and the overall control system is respectively connected to the sub-tank level gauges and the molten salt pumps; and the molten salt pump uses a short-shaft pump.

[0012] The aforementioned molten salt storage tank system, wherein the connecting pipe is provided with an expansion joint, an automatic exhaust valve and a pneumatic stop valve, an air intake valve is provided between the connecting pipe and the hot molten salt mother tank, and an air intake valve is also provided between the connecting pipe and the cold molten salt mother tank, and the overall control system is respectively connected to the automatic exhaust valve, the pneumatic stop valve and the air intake valve.

[0013] In the aforementioned molten salt storage tank system, a safety valve is also provided on the gas pressure stabilizing tank.

[0014] In the aforementioned molten salt storage tank system, an electric stop valve is connected between the hot molten salt mother tank and the gas pressure regulating tank, an electric stop valve is also connected between the cold molten salt mother tank and the gas pressure regulating tank, and the overall control system is connected to the electric stop valve.

[0015] In the aforementioned molten salt storage tank system, air or nitrogen is arranged in the gas pressure stabilizing tank. When the molten salt is Solar Salt, the gas arranged in the gas pressure stabilizing tank is air. When the molten salt is Hitec Salt, the gas arranged in the gas pressure stabilizing tank is nitrogen.

[0016] A method for operating a molten salt storage tank system comprises the following steps:

[0017] During the initial startup or startup after maintenance, there is no molten salt in the interconnecting pipe, the hot molten salt sub-tank and the cold molten salt sub-tank, the gas pressure regulating tank and the compressor are started, the pneumatic stop valve is opened, and the molten salt enters the interconnecting pipe under the action of the pressure difference, the air in the interconnecting pipe and the hot molten salt sub-tank and the cold molten salt sub-tank is completely exhausted, the automatic exhaust valve is closed, and the pneumatic stop valve is closed;

[0018] When the hot molten salt sub-tank, cold molten salt sub-tank, and molten salt pump need to be repaired or the hot molten salt sub-tank and cold molten salt sub-tank leak, the molten salt transportation of the hot molten salt sub-tank and cold molten salt sub-tank is disconnected, the gas pressure regulating tank and the compressor are stopped, and the air inlet valve on the upper part of the connecting pipe is opened. The transportation process is disrupted, and the molten salt in the hot molten salt mother tank and the cold molten salt mother tank is no longer sucked into the hot molten salt sub-tank and the cold molten salt sub-tank. The salt drainage valves of the hot molten salt sub-tank and the cold molten salt sub-tank are opened, and the molten salt in the hot molten salt sub-tank and the cold molten salt sub-tank is drained into the salt drainage tank, and the molten salt is introduced into the hot molten salt mother tank and the cold molten salt mother tank through the salt drainage pump.

[0019] In the above-mentioned operation method of a molten salt storage tank system, the relationship between the top pressure of the hot molten salt mother tank and the cold molten salt mother tank and the molten salt liquid level is: Pg = ρg (Hsiphon-Hsalt), wherein Pg is the gas pressure at the top of the molten salt mother tank, Pa; ρ is the density of the molten salt, kg / m 3 ; g-gravitational acceleration, m / s 2 ; Hsiphon-the height of the connecting pipe A end from the bottom of the hot molten salt mother tank and the cold molten salt mother tank, m; Hsalt-the molten salt liquid level in the tank, m. The radar level gauge, gas pressure regulating tank and compressor transmit data to the overall control system, and the overall control system adjusts the pressure according to the above relationship;

[0020] The gas pressure of the hot molten salt mother tank and the cold molten salt mother tank is constant, and the pressure of the gas in the top space of the hot molten salt mother tank and the cold molten salt mother tank is always maintained in the same range [P L ,P H ], P H =ρg(Hsiphon-Hsalt),P L =ρg(Hsiphon-Hsalt-5.5), where 5.5m is the self-imbibition height of molten salt;

[0021] When adjusting the pressure, the compressor pressurizes the gas to the required pressure of the hot molten salt mother tank and the cold molten salt mother tank. When the pressure of the gas pressure regulating tank reaches the rated pressure P H After that, the compressor stops running. When the pressure of the gas surge tank drops to P L When the compressor starts automatically, it will increase the pressure of the gas pressure regulating tank;

[0022] During the initial startup or startup after maintenance, there is no molten salt in the connecting pipe, hot molten salt sub-tank and cold molten salt sub-tank. Start the gas pressure regulating tank and compressor to keep the top pressure of the hot molten salt mother tank and the cold molten salt mother tank at P H Pa.

[0023] Compared with the prior art, the molten salt tank of the present invention is a pressure-bearing structure, adopts a large height-to-diameter ratio, and adds a molten salt sub-tank. The main tank and the sub-tank are connected by a siphon tube. The molten salt pump uses a short-axis pump installed on the sub-tank, which not only solves the problems of vibration and deformation of the long-axis pump, but also greatly reduces the amount of invalid salt in the molten salt tank, saving investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the control relationship between the overall control system of the present invention and the gas pressure regulating tank, compressor, radar level gauge, safety valve, salt-repelling pump, salt-repelling valve, sub-tank level gauge, molten salt pump, automatic exhaust valve, pneumatic stop valve, air intake valve, and electric stop valve.

[0026] Figure markings: 1-total control system, 2-hot molten salt mother tank, 3-cold molten salt mother tank, 4-gas pressure regulating tank, 5-compressor, 6-radar level gauge, 7-safety valve, 8-connecting pipe, 9-A end, 10-B end, 11-hot molten salt sub-tank, 12-salt drainage tank, 13-cold molten salt sub-tank, 14-salt drainage pump, 15-salt drainage valve, 16-sub-tank level gauge, 17-molten salt pump, 18-expansion joint, 19-automatic exhaust valve, 20-pneumatic stop valve, 21-intake valve, 22-electric stop valve.

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0028] Embodiment 1 of the present invention: A molten salt storage tank system includes a molten salt mother tank and a total control system 1, wherein the molten salt mother tank includes a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 includes an A end 9 and a B end 10, the connecting pipe 8A end 9 of the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively passes through the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the total control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure stabilizing tank 4 and the compressor 5, and the total control system 1 is respectively connected to the gas pressure stabilizing tank 4, the compressor 5, the radar level gauge 6, and the safety valve 7.

[0029] Embodiment 2 of the present invention: A molten salt storage tank system comprises a molten salt mother tank and a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the connecting pipe 8 comprises an A end 9 and a B end 10, The A end 9 of the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively penetrates the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5; the overall control system 1 is respectively connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6 and the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12.

[0030] Embodiment 3 of the present invention: A molten salt storage tank system comprises a molten salt mother tank and also comprises a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 comprises an A end 9 and a B end 10, the connecting pipe 8A end 9 of the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively penetrates the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the general control system 1 is connected to the radar level gauge 6, the safety valve 7, the gas pressure stabilizing tank 4 and the compressor 5 respectively The overall control system 1 is respectively connected to the gas pressure stabilizing tank 4, the compressor 5, the radar level gauge 6, and the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt diversion tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to the cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt diversion tank 12, a salt diversion pump 14 is arranged on the salt diversion tank 12, and a salt diversion valve 15 is arranged between the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 and the salt diversion tank 12, and the overall control system 1 is respectively connected to the salt diversion pump 14 and the salt diversion valve 15.

[0031] Embodiment 4 of the present invention: A molten salt storage tank system comprises a molten salt mother tank and also comprises a total control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 comprises an A end 9 and a B end 10, the connecting pipe 8A end 9 of the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively passes through the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the total control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure stabilizing tank 4 and the compressor 5, and the total control system 1 is respectively connected to the gas pressure stabilizing tank 4, the compressor 5, the radar level gauge 6, the safety valve 7 ; The B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to a hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to a salt-dispersing tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to a cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank The tanks 13 are also connected to the salt diversion tank 12, which is provided with a salt diversion pump 14. Salt diversion valves 15 are provided between the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 and the salt diversion tank 12, and the overall control system 1 is connected to the salt diversion pump 14 and the salt diversion valve 15, respectively; the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are provided with sub-tank liquid level gauges 16 and molten salt pumps 17, and the overall control system 1 is connected to the sub-tank liquid level gauges 16 and the molten salt pumps 17, respectively.

[0032] Embodiment 5 of the present invention: A molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the connecting pipe 8 comprises A end 9 and B end 10, the connecting pipe 8A end 9 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively penetrates the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the overall control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5, the overall control system 1 is respectively connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6, the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, The hot molten salt sub-tank 11 is connected to a salt draining tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to a cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt draining tank 12, and a salt draining pump 14 is arranged on the salt draining tank 12, and a salt draining valve 15 is arranged between the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 and the salt draining tank 12, and the overall control system 1 is respectively connected to the salt draining pump 14 and the salt draining valve 15. 5 connection; the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are both provided with a sub-tank level gauge 16 and a molten salt pump 17, and the overall control system 1 is respectively connected to the sub-tank level gauge 16 and the molten salt pump 17; the connecting pipe 8 is provided with an expansion joint 18, an automatic exhaust valve 19 and a pneumatic stop valve 20, an air intake valve 21 is provided between the connecting pipe 8 and the hot molten salt mother tank 2, and an air intake valve 21 is also provided between the connecting pipe 8 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the automatic exhaust valve 19, the pneumatic stop valve 20 and the air intake valve 21.

[0033] Embodiment 6 of the present invention: A molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the connecting pipe 8 includes an A end 9 and The B end 10, the A end 9 of the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively penetrate the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the overall control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5, the overall control system 1 is respectively connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6, the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the bottom of the hot molten salt mother tank 2. A salt diversion tank 12 is connected; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to a cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt diversion tank 12, a salt diversion pump 14 is arranged on the salt diversion tank 12, and a salt diversion valve 15 is arranged between the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 and the salt diversion tank 12, and the overall control system 1 is respectively connected to the salt diversion pump 14 and the salt diversion valve 15; the hot molten salt sub-tank 11 The sub-tank level gauge 16 and the molten salt pump 17 are both provided on the cold molten salt sub-tank 13, and the overall control system 1 is respectively connected to the sub-tank level gauge 16 and the molten salt pump 17; the connecting pipe 8 is provided with an expansion joint 18, an automatic exhaust valve 19 and a pneumatic stop valve 20, an air intake valve 21 is provided between the connecting pipe 8 and the hot molten salt mother tank 2, and an air intake valve 21 is also provided between the connecting pipe 8 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the automatic exhaust valve 19, the pneumatic stop valve 20 and the air intake valve 21; the gas pressure stabilizing tank 4 is also provided with a safety valve 7.

[0034] Embodiment 7 of the present invention: A molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 comprises an A end 9 and a B end 10, the hot molten salt mother tank 2 and the cold molten salt mother tank The connecting pipe 8A end 9 of 3 respectively penetrates the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5, and the overall control system 1 is respectively connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6, and the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to the cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt diversion tank 12, and the salt diversion tank 12 is provided with a salt diversion pump 14, and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are provided with a salt diversion valve 15 between the salt diversion tank 12, and the overall control system 1 is respectively connected to the salt diversion pump 14 and the salt diversion valve 15; the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are both provided with a sub-tank level gauge 16 and a molten salt pump 17, and the overall control system 1 is respectively connected to the sub-tank level gauge 16 and the molten salt pump 17; the An expansion joint 18, an automatic exhaust valve 19 and a pneumatic stop valve 20 are provided on the connecting pipe 8, an air intake valve 21 is provided between the connecting pipe 8 and the hot molten salt mother tank 2, and an air intake valve 21 is also provided between the connecting pipe 8 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the automatic exhaust valve 19, the pneumatic stop valve 20 and the air intake valve 21; a safety valve 7 is also provided on the gas pressure stabilizing tank 4; an electric stop valve 22 is connected between the hot molten salt mother tank 2 and the gas pressure stabilizing tank 4, an electric stop valve 22 is also connected between the cold molten salt mother tank 3 and the gas pressure stabilizing tank 4, and the overall control system 1 is connected to the electric stop valve 22.

[0035] Embodiment 8 of the present invention: A molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 comprises an A end 9 and a B end 10, and the connecting pipe 8A of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 The ends 9 respectively penetrate the hot molten salt mother tank 2 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5, and the overall control system 1 is respectively connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6, and the safety valve 7; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to the cold molten salt sub-tank 13, and the cold molten salt sub-tank 13 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12. At the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt diversion tank 12, and the salt diversion tank 12 is provided with a salt diversion pump 14, and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are provided with a salt diversion valve 15 between the salt diversion tank 12, and the overall control system 1 is respectively connected to the salt diversion pump 14 and the salt diversion valve 15; the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are both provided with a sub-tank level gauge 16 and a molten salt pump 17, and the overall control system 1 is respectively connected to the sub-tank level gauge 16 and the molten salt pump 17; the connecting pipe 8 is provided with an expansion joint 18 and an automatic exhaust valve 19 and a pneumatic stop valve 20, an air intake valve 21 is arranged between the connecting pipe 8 and the hot molten salt mother tank 2, and an air intake valve 21 is also arranged between the connecting pipe 8 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the automatic exhaust valve 19, the pneumatic stop valve 20, and the air intake valve 21; a safety valve 7 is also arranged on the gas pressure stabilizing tank 4; an electric stop valve 22 is connected between the hot molten salt mother tank 2 and the gas pressure stabilizing tank 4, and an electric stop valve 22 is also connected between the cold molten salt mother tank 3 and the gas pressure stabilizing tank 4, and the overall control system 1 is connected to the electric stop valve 22; air or nitrogen is arranged in the gas pressure stabilizing tank 4, when the molten salt is Solar Salt, the gas arranged in the gas pressure stabilizing tank 4 is air, and when the molten salt is Hitec Salt, the gas arranged in the gas pressure stabilizing tank 4 is nitrogen.

[0036] The height of the A end 9 of the connecting pipe 8 is 0.3 meters from the bottom of the cold molten salt mother tank 3. There is a steam exhaust port at the top of the connecting pipe 8, which is connected to the atmosphere through an automatic exhaust valve and a stop valve. There is an air inlet pipe at the top of the connecting pipe 8, which is connected to the top space of the mother tank through a stop valve. The connecting pipe 8 is provided with an expansion joint on the pipe section connected to the sub-tank to ensure that the siphon pipe can expand freely up and down, and an electric heating anti-condensation system is arranged outside the siphon pipe.

[0037] The sub-tank is a fully sealed structure, and its maximum withstand pressure is the sum of the static pressure of the highest liquid level of the mother tank molten salt and the top gas pressure. The sub-tank is connected to the mother tank through the connecting pipe 8, and the sub-tank can also be installed below the lowest liquid level of the mother tank. The sub-tank is arranged horizontally, with a cylinder diameter in the range of 3.0 to 5.0 meters, and the capacity ensures that the maximum flow of the molten salt pump is maintained for 5 minutes.

[0038] Embodiment 9 of the present invention: A method for operating a molten salt storage tank system, comprising the following steps:

[0039] During the initial startup or startup after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, the gas pressure regulating tank 4 and the compressor 5 are started, the pneumatic stop valve 20 is opened, and the molten salt enters the connecting pipe 8 under the action of the pressure difference, and the air in the connecting pipe 8 and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is completely exhausted, the automatic exhaust valve 19 is closed, and the pneumatic stop valve 20 is closed;

[0040] When the hot molten salt sub-tank 11, the cold molten salt sub-tank 13, and the molten salt pump 17 need to be repaired or the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 leak, the molten salt transportation of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is disconnected, the gas pressure regulating tank 4 and the compressor 5 are stopped, and the air inlet valve 21 on the upper part of the connecting pipe 8 is opened. The transportation process is disrupted, and the molten salt in the hot molten salt mother tank 2 and the cold molten salt mother tank 3 is no longer sucked into the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13. The salt drainage valve 15 of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is opened, and the molten salt in the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is drained into the salt drainage tank 12, and the molten salt is introduced into the hot molten salt mother tank 2 and the cold molten salt mother tank 3 through the salt drainage pump 14.

[0041] Embodiment 10 of the present invention: A method for operating a molten salt storage tank system, comprising the following steps:

[0042] During the initial startup or startup after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, the gas pressure regulating tank 4 and the compressor 5 are started, the pneumatic stop valve 20 is opened, and the molten salt enters the connecting pipe 8 under the action of the pressure difference, and the air in the connecting pipe 8 and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is completely exhausted, the automatic exhaust valve 19 is closed, and the pneumatic stop valve 20 is closed;

[0043] When the hot molten salt sub-tank 11, the cold molten salt sub-tank 13, and the molten salt pump 17 need to be repaired or the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 leak, the molten salt transportation of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is disconnected, the gas pressure regulating tank 4 and the compressor 5 are stopped, and the air inlet valve 21 on the upper part of the connecting pipe 8 is opened. The transportation process is disrupted, and the molten salt in the hot molten salt mother tank 2 and the cold molten salt mother tank 3 is no longer sucked into the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, and the hot molten salt sub-tank 1 is opened. 1. The salt diversion valve 15 of the cold molten salt sub-tank 13 diverts the molten salt in the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 into the salt diversion tank 12, and introduces the molten salt into the hot molten salt mother tank 2 and the cold molten salt mother tank 3 through the salt diversion pump 14; the relationship between the top pressure of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 and the molten salt liquid level is: Pg = ρg (Hsiphon-Hsalt), wherein Pg is the gas pressure at the top of the molten salt mother tank, Pa; ρ is the density of the molten salt, kg / m 3 ; g-gravitational acceleration, m / s 2 ; Hsiphon-the height of the end 9 of the connecting pipe 8A from the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, m; Hsalt-the liquid level of the molten salt in the tank, m. The radar level gauge 6, the gas pressure regulating tank 4 and the compressor 5 transmit the data to the overall control system 1, and the overall control system 1 adjusts the pressure according to the above relationship;

[0044] The gas pressure of the hot molten salt mother tank and the cold molten salt mother tank is constant, and the pressure of the gas in the top space of the hot molten salt mother tank and the cold molten salt mother tank is always maintained in the same range [P L ,P H ], P H =ρg(Hsiphon-Hsalt),P L =ρg(Hsiphon-Hsalt-5.5), where 5.5m is the self-imbibition height of molten salt;

[0045] When adjusting the pressure, the compressor 5 pressurizes the gas to the pressure required by the hot molten salt mother tank 2 and the cold molten salt mother tank 3. When the pressure of the gas pressure regulating tank 4 reaches the rated pressure P H After that, the compressor 5 stops running, and when the pressure of the gas surge tank 4 drops to P L When the compressor 5 starts automatically to increase the pressure of the gas pressure-stabilizing tank 4;

[0046] During the initial startup or startup after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, and the gas pressure regulating tank 4 and the compressor 5 are started to keep the top pressure of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 (P H +17000)Pa.

[0047] Embodiment 11 of the present invention: A molten salt storage tank system, comprising a molten salt mother tank, and also comprising a general control system 1, wherein the molten salt mother tank comprises a hot molten salt mother tank 2 and a cold molten salt mother tank 3, a gas pressure stabilizing tank 4 is arranged between the hot molten salt mother tank 2 and the cold molten salt mother tank 3, a compressor 5 is arranged on the gas pressure stabilizing tank 4, a radar level gauge 6, a safety valve 7 and a connecting pipe 8 are arranged on the top of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, an anti-condensation electric heater is arranged on the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, the connecting pipe 8 comprises an A end 9 and a B end 10, and the connecting pipe 8 of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 The A end 9 passes through the hot molten salt mother tank 2 and the cold molten salt mother tank 3 respectively, and the overall control system 1 is connected to the radar level gauge 6, the safety valve 7, the gas pressure regulating tank 4 and the compressor 5 respectively, and the overall control system 1 is connected to the gas pressure regulating tank 4, the compressor 5, the radar level gauge 6 and the safety valve 7 respectively; the B end 10 of the connecting pipe 8 on the hot molten salt mother tank 2 is connected to the hot molten salt sub-tank 11, the height of the hot molten salt sub-tank 11 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12; the B end 10 of the connecting pipe 8 on the cold molten salt mother tank 3 is connected to the cold molten salt sub-tank 13, the height of the cold molten salt sub-tank 13 is lower than the bottom height of the hot molten salt mother tank 2, and the hot molten salt sub-tank 11 is connected to the salt draining tank 12. At the bottom height of the cold molten salt mother tank 3, the cold molten salt mother tank 3, the cold molten salt mother tank 3 and the cold molten salt sub-tank 13 are also respectively connected to the salt diversion tank 12, and the salt diversion tank 12 is provided with a salt diversion pump 14, and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are provided with a salt diversion valve 15 between the salt diversion tank 12, and the overall control system 1 is respectively connected to the salt diversion pump 14 and the salt diversion valve 15; the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 are both provided with a sub-tank level gauge 16 and a molten salt pump 17, and the overall control system 1 is respectively connected to the sub-tank level gauge 16 and the molten salt pump 17; the connecting pipe 8 is provided with an expansion joint 18 and an automatic exhaust valve 19 and a pneumatic stop valve 20, an air intake valve 21 is arranged between the connecting pipe 8 and the hot molten salt mother tank 2, and an air intake valve 21 is also arranged between the connecting pipe 8 and the cold molten salt mother tank 3, and the overall control system 1 is respectively connected to the automatic exhaust valve 19, the pneumatic stop valve 20, and the air intake valve 21; the gas pressure stabilizing tank 4 is also provided with a safety valve 7; an electric stop valve 22 is connected between the hot molten salt mother tank 2 and the gas pressure stabilizing tank 4, and an electric stop valve 22 is also connected between the cold molten salt mother tank 3 and the gas pressure stabilizing tank 4, and the overall control system 1 is connected to the electric stop valve 22; air or nitrogen is arranged in the gas pressure stabilizing tank 4, when the molten salt is Solar Salt, the gas arranged in the gas pressure stabilizing tank 4 is air, and when the molten salt is Hitec Salt, the gas arranged in the gas pressure stabilizing tank 4 is nitrogen;

[0048] During the initial startup or startup after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, the gas pressure regulating tank 4 and the compressor 5 are started, the pneumatic stop valve 20 is opened, and the molten salt enters the connecting pipe 8 under the action of the pressure difference, and the air in the connecting pipe 8 and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is completely exhausted, the automatic exhaust valve 19 is closed, and the pneumatic stop valve 20 is closed;

[0049] When the hot molten salt sub-tank 11, the cold molten salt sub-tank 13, and the molten salt pump 17 need to be repaired or the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 leak, the molten salt transportation of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is disconnected, the gas pressure regulating tank 4 and the compressor 5 are stopped, and the air inlet valve 21 on the upper part of the connecting pipe 8 is opened, the transportation process is destroyed, and the molten salt in the hot molten salt mother tank 2 and the cold molten salt mother tank 3 is no longer sucked into the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, and the salt diversion valve 15 of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is opened, and the molten salt in the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is diverted into the salt diversion tank 12, and the molten salt is introduced into the hot molten salt mother tank 2 and the cold molten salt mother tank 3 by the salt diversion pump 14; the relationship between the top pressure of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 and the molten salt liquid level is:

[0050] Pg = ρg (Hsiphon - Hsalt), where Pg is the gas pressure above the molten salt mother tank, Pa; ρ is the density of the molten salt, kg / m 3 ; g-gravitational acceleration, m / s 2 ; Hsiphon-the height of the end 9 of the connecting pipe 8A from the bottom of the hot molten salt mother tank 2 and the cold molten salt mother tank 3, m; Hsalt-the liquid level of the molten salt in the tank, m. The radar level gauge 6, the gas pressure regulating tank 4 and the compressor 5 transmit the data to the overall control system 1, and the overall control system 1 adjusts the pressure according to the above relationship;

[0051] The gas pressure of the hot molten salt mother tank and the cold molten salt mother tank is constant, and the pressure of the gas in the top space of the hot molten salt mother tank and the cold molten salt mother tank is always maintained in the same range [P L ,P H ], P H =ρg(Hsiphon-Hsalt),P L =ρg(Hsiphon-Hsalt-5.5), where 5.5m is the self-imbibition height of molten salt;

[0052] When adjusting the pressure, the compressor 5 pressurizes the gas to the pressure required by the hot molten salt mother tank 2 and the cold molten salt mother tank 3. When the pressure of the gas pressure regulating tank 4 reaches the rated pressure P H After that, the compressor 5 stops running, and when the pressure of the gas surge tank 4 drops to P LWhen the compressor 5 starts automatically to increase the pressure of the gas pressure-stabilizing tank 4;

[0053] When starting up for the first time or after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, and the gas pressure regulating tank 4 and the compressor 5 are started to keep the top pressure of the hot molten salt mother tank 2 and the cold molten salt mother tank 3 at P H Pa.

[0054] Among them, the hot molten salt mother tank 2 has a diameter of 28 meters and a height of 27.6 meters; the cold molten salt mother tank 3 has a diameter of 28 meters and a height of 26.2 meters; the molten salt pump 17 has a pump shaft length of 5 meters, and the amount of invalid salt is 1,450 tons, accounting for 2.2%.

[0055] A trough solar thermal power station of our company is designed with 2 hot molten salt tanks, each with a diameter of 38 meters and a height of 15 meters; 2 cold molten salt tanks, each with a diameter of 37 meters and a height of 15 meters; the total molten salt volume is 60,050 tons. The pump shaft length of the molten salt pump is greater than 15 meters, the minimum residual volume of the hot molten salt tank is 800 cubic meters, and the minimum residual volume of the cold molten salt tank is 760 cubic meters. The total amount of invalid salt is 5,945 tons, accounting for 10% of the total salt volume. 4 hot molten salt pumps, 3 in operation and 1 in standby, 4 cold molten salt pumps, 3 in operation and 1 in standby, with a total investment of 60 million yuan;

[0056] Compared with a certain trough solar thermal power station, the embodiment of the present invention can save 6000×(5945-1450)=26.97 million yuan by purchasing molten salt, based on the binary solar salt price of 6000 yuan / ton. 4 hot molten salt pumps and 4 cold molten salt pumps, with a total investment of 45 million yuan, can save 15 million yuan, and the total investment can save 41.97 million yuan.

[0057] The working principle of an embodiment of the present invention is as follows: when the present invention is initially started or started after maintenance, there is no molten salt in the connecting pipe 8, the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13, the gas pressure regulating tank 4 and the compressor 5 are started, the pneumatic stop valve 20 is opened, and the molten salt enters the connecting pipe 8 under the action of the pressure difference, the air in the connecting pipe 8 and the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is completely exhausted, the automatic exhaust valve 19 is closed, and the pneumatic stop valve 20 is closed;

[0058] When the hot molten salt sub-tank 11, the cold molten salt sub-tank 13, and the molten salt pump 17 need to be repaired or the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 leak, the molten salt transportation of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is disconnected, the gas pressure regulating tank 4 and the compressor 5 are stopped, and the air inlet valve 21 on the upper part of the connecting pipe 8 is opened. The transportation process is disrupted, and the molten salt in the hot molten salt mother tank 2 and the cold molten salt mother tank 3 is no longer sucked into the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13. The salt drainage valve 15 of the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is opened, and the molten salt in the hot molten salt sub-tank 11 and the cold molten salt sub-tank 13 is drained into the salt drainage tank 12, and the molten salt is introduced into the hot molten salt mother tank 2 and the cold molten salt mother tank 3 through the salt drainage pump 14.

Claims

1. A molten salt storage tank system, comprising a molten salt mother tank, characterized in that: The invention also comprises a total control system (1), wherein the molten salt mother tank comprises a hot molten salt mother tank (2) and a cold molten salt mother tank (3), a gas pressure stabilizing tank (4) is arranged between the hot molten salt mother tank (2) and the cold molten salt mother tank (3), a compressor (5) is arranged on the gas pressure stabilizing tank (4), a radar level gauge (6), a safety valve (7) and a connecting pipe (8) are arranged on the top of the hot molten salt mother tank (2) and the cold molten salt mother tank (3), and the hot molten salt mother tank (2) and the cold molten salt mother tank (3) are respectively provided with a pressure regulating tank (4) and a pressure regulating tank (5). The bottom of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) are both provided with anti-condensation electric heaters, the connecting pipe (8) includes an A end (9) and a B end (10), the A end (9) of the connecting pipe (8) of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) respectively penetrates the hot molten salt mother tank (2) and the cold molten salt mother tank (3), and the overall control system (1) is respectively connected to the gas pressure stabilizing tank (4), the compressor (5), the radar level gauge (6), and the safety valve (7).

2. A molten salt storage tank system according to claim 1, characterized in that: The B end (10) of the connecting pipe (8) on the hot molten salt mother tank (2) is connected to a hot molten salt sub-tank (11), the height of the hot molten salt sub-tank (11) is lower than the bottom height of the hot molten salt mother tank (2), and the hot molten salt mother tank (2) and the hot molten salt sub-tank (11) are connected to a salt draining tank (12).

3. A molten salt storage tank system according to claim 2, characterized in that: The B end (10) of the connecting pipe (8) on the cold molten salt mother tank (3) is connected to a cold molten salt sub-tank (13); the height of the cold molten salt sub-tank (13) is lower than the bottom height of the cold molten salt mother tank (3); the cold molten salt mother tank (3) and the cold molten salt sub-tank (13) are also respectively connected to a salt diversion tank (12); a salt diversion pump (14) is provided on the salt diversion tank (12); a salt diversion valve (15) is provided between the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) and the salt diversion tank (12); and the overall control system (1) is respectively connected to the salt diversion pump (14) and the salt diversion valve (15).

4. A molten salt storage tank system according to claim 3, characterized in that: The hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) are both provided with a sub-tank liquid level meter (16) and a molten salt pump (17), and the overall control system (1) is connected to the sub-tank liquid level meter (16) and the molten salt pump (17), respectively.

5. A molten salt storage tank system according to claim 4, characterized in that: The connecting pipe (8) is provided with an expansion joint (18), an automatic exhaust valve (19) and a pneumatic stop valve (20); an air intake valve (21) is provided between the connecting pipe (8) and the hot molten salt mother tank (2); an air intake valve (21) is also provided between the connecting pipe (8) and the cold molten salt mother tank (3); and the overall control system (1) is connected to the automatic exhaust valve (19), the pneumatic stop valve (20) and the air intake valve (21), respectively.

6. A molten salt storage tank system according to claim 5, characterized in that: The gas pressure-stabilizing tank (4) is also provided with a safety valve (7).

7. A molten salt storage tank system according to claim 6, characterized in that: An electric stop valve (22) is connected between the hot molten salt mother tank (2) and the gas pressure regulating tank (4), an electric stop valve (22) is also connected between the cold molten salt mother tank (3) and the gas pressure regulating tank (4), and the overall control system (1) is connected to the electric stop valve (22).

8. A molten salt storage tank system according to claim 7, characterized in that: The gas pressure stabilizing tank (4) is provided with air or nitrogen. When the molten salt is Solar Salt, the gas provided in the gas pressure stabilizing tank (4) is air. When the molten salt is Hitec Salt, the gas provided in the gas pressure stabilizing tank (4) is nitrogen.

9. The operating method for the system according to claims 1 to 8, characterized in that: The following steps are involved: During initial startup or startup after maintenance, there is no molten salt in the connecting pipe (8), the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13), the gas pressure regulating tank (4) and the compressor (5) are started, the pneumatic stop valve (20) is opened, and the molten salt enters the connecting pipe (8) under the action of the pressure difference, the air in the connecting pipe (8) and the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) is completely exhausted, the automatic exhaust valve (19) is closed, and the pneumatic stop valve (20) is closed; When the hot molten salt sub-tank (11), the cold molten salt sub-tank (13), and the molten salt pump (17) need to be repaired or the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) leak, the molten salt transportation of the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) is disconnected, the gas pressure regulating tank (4) and the compressor (5) are stopped, and the air inlet valve (21) on the upper part of the connecting pipe (8) is opened, the transportation process is disrupted, and the hot molten salt mother tank (2) is disconnected. The molten salt in the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) is no longer sucked into the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13), the salt diversion valves (15) of the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) are opened, and the molten salt in the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13) is diverted into the salt diversion tank (12), and the molten salt is introduced into the hot molten salt mother tank (2) and the cold molten salt mother tank (3) through the salt diversion pump (14).

10. The operating method of the system according to claim 9, characterized in that: The relationship between the gas pressure at the top of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) and the molten salt liquid level is: Pg = ρg (Hsiphon-Hsalt), where Pg is the gas pressure at the top of the molten salt mother tank, Pa; ρ is the density of the molten salt, kg / m 3 ; g-gravitational acceleration, m / s 2 ; Hsiphon-the height of the highest point of the connecting pipe (8) from the bottom of the hot molten salt mother tank (2) or the cold molten salt mother tank (3), m; Hsalt-the liquid level of the molten salt in the tank, m. The radar level gauge (6), the gas pressure regulating tank (4) and the compressor (5) transmit data to the overall control system (1), and the overall control system (1) adjusts the pressure according to the above relationship; In order to simplify the system, the gas pressure Pg of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) is constant, and the pressure of the gas in the top space of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) is always maintained in the same range [P L ,P H ], P H =ρg(Hsiphon-Hsalt),P L =ρg(Hsiphon-Hsalt-5.5), where 5.5m is the self-imbibition height of molten salt; When adjusting the pressure, the compressor (5) pressurizes the gas to the pressure required by the hot molten salt mother tank (2) and the cold molten salt mother tank (3). When the pressure of the gas pressure regulating tank (4) reaches the rated pressure P H After that, the compressor (5) stops running. When the pressure of the gas surge tank (4) is lower than P L When the pressure of the gas pressure regulating tank (4) is increased, the compressor (5) automatically starts to increase the pressure of the gas pressure regulating tank (4); When the system is initially started or started after maintenance, there is no molten salt in the connecting pipe (8), the hot molten salt sub-tank (11) and the cold molten salt sub-tank (13), and the gas pressure regulating tank (4) and the compressor (5) are started to keep the top pressure of the hot molten salt mother tank (2) and the cold molten salt mother tank (3) at P H Pa.

Images