CN216845130U - Fused salt storage tank and fused salt electric heat long-time energy storage device - Google Patents

Abstract

The utility model provides a fused salt storage tank and a fused salt electric heat accumulation long-time energy storage device, which can directly replace the existing coal-fired and gas-fired industrial steam boiler, thereby promoting the centralized gas supply and heat supply through fused salt heat accumulation in an industrial park; meanwhile, after the fused salt electric heat storage long-term energy storage device disclosed by the invention is combined with a supercritical carbon dioxide generator set, a novel high-efficiency 'electricity-heat-electricity' technical mode is generated, and the fused salt electric heat storage long-term energy storage device can replace the existing pumped storage power station and chemical energy storage station and becomes a large-capacity long-term energy storage technology. The utility model has the characteristics of compact structure, system are simple, the heat-retaining is with low costs, exothermic efficiency is high, the system heat waste is little, electric heat and thermoelectric conversion efficiency are all high, can realize the production of modularization, standardization, batchization, batch production, possess security, economy, flexibility, still possess that the regulating power is strong, construction period is short, the site selection requires lowly and construction scale is nimble.

Description

Fused salt storage tank and fused salt electric heat long-time energy storage device

Technical Field

The utility model discloses a fused salt storage tank and fused salt electricity heat accumulation long term energy memory belongs to novel energy storage technical field.

Background

With the social development, the deterioration degree of the global ecological environment is more and more severe, the control of the carbon emission is more and more severe, the structural adjustment of energy is accelerated to develop towards green energy, and the green energy such as solar energy, wind energy and the like is paid unprecedented attention. With the further improvement of the new energy installation proportion, the measures taken for ensuring the consumption of the new energy are mainly as follows: firstly, the coal-electricity deep peak regulation reconstruction: the minimum power generation amount is reduced; secondly, newly building an energy storage facility: the energy generation amount of new energy is stored and shifted to the peak of the power consumption for use, the deep peak regulation of the coal power is the short-term priority, and the matching of an energy storage system is the inevitable choice for the long-term development in the future! Several commonly used energy storage methods are currently compared:

pumped storage, although the technical route is mature, the pumped storage has higher cost and is difficult to reduce in the future. If no existing upper or lower reservoir is available, the investment and movement costs of the pumped storage unit are still high; in addition, the construction period generally takes 7-8 years, which is obviously behind the construction period of new energy, and the water is not easy to be thirsty when the water is far away; secondly, geographical conditions for construction of the storage are rare in northwest regions, and large-scale construction of the storage is not practical. Therefore, although the pumped storage technology is mature, the cost is only increased and cannot be reduced.

Electrochemical energy storage, which is currently limited by high cost, short life and low safety. The cost of the energy storage link of each degree of electricity of electrochemical energy storage is higher; the battery is required to be replaced in the operation life of 8-10 years generally, and the environmental protection problem still exists after the battery is scrapped; there are also safety issues with frequent fires or explosions. Whether the future electrochemical energy storage cost can continuously decrease is analyzed from two aspects: firstly, the cost reduction cannot be unlimited and endless; secondly, the reserve of lithium is limited, and the cost is difficult to feed in the future. Therefore, electrochemical energy storage itself needs a technological revolution to solve a series of problems of safety, environmental protection, cost, life, etc.

Under the background of high proportion renewable energy installation, in order to reduce and abandon wind, abandon light, ensure that the electric wire netting operation is safe, satisfy the power consumption peak demand, need a novel energy storage technology of energy translation type with low costs, extensive, high efficiency, high security, environmental protection low carbon urgently.

On the other hand, with the social development and the improvement of the living standard of people, the day-night difference of electricity utilization structures in China is larger and larger, the demand of peak shifting and valley filling is stronger, and the phenomena of wind abandoning and light abandoning are more and more serious; the economic speed-increasing gear-shifting of China develops a new normal state step by step, and the industrial structure is gradually converted from a middle-low end to a middle-high end. The adjustment of the industrial structure leads to the continuous increase of the power consumption ratio of the third industry and the urban and rural residents, the power consumption characteristic determines that the peak-valley difference rate of the load curve is obviously higher than that of the second industry, the peak-valley difference rate of the power consumption side in China has a trend of going high, and the electric energy storage and heat storage and adjustable power supply construction requirements of the user side are continuously increased.

The heat energy storage technology is compared with pumped storage and air compression energy storage technology, all belong to long-term energy storage, but the equipment technology of heat energy storage is relatively simple mature, the key is that heat energy storage can absorb unstable and very strong renewable power of volatility, and pumped storage and air compression technology then need stable low ebb electricity to support, nevertheless with coal-fired power plant reduction and peak shaving ability decline, once renewable energy becomes energy main force army, the low ebb electricity becomes history, pumped storage and air compression energy storage equipment will be idle, huge investment will become the rubbish asset.

Compared with chemical battery energy storage, the thermal energy storage has the outstanding characteristics of large energy storage capacity and low unit energy storage cost, which cannot be competitive with the chemical battery energy storage, but the flexible thermal energy storage is obviously inferior to the chemical battery energy storage. Therefore, the flexibility of thermal energy storage applications must be addressed.

The main technical approaches of the traditional molten salt energy storage are as follows: the system adopts a heat storage mode of double storage tanks, namely a hot molten salt storage tank, a cold molten salt storage tank, a plurality of high-power special molten salt heaters, a plurality of high-temperature molten salt pumps, a plurality of low-temperature molten salt pumps, a tube type molten salt heat exchanger, a salt dredging tank and the like, and is connected into a system through a long molten salt conveying pipeline, in order to prevent the molten salt conveying pipeline from being frozen in the using process, an electric tracing band is additionally arranged on the conveying pipeline, and an auxiliary salt dredging system is additionally arranged; in addition, the manufacture of the fused salt double storage tank needs to be completed on site, so that the construction period is long, and the manufacture cost and the manufacture quality are not easy to control. In a word, each part device in the traditional fused salt double-storage-tank energy storage system cannot be produced in a standardized manner in batch, the heat storage cost is too high, the heat release efficiency is promoted and limited, the heat loss of the system is large, the system is relatively overstaffed and not compact, and the modularized, standardized, mass and industrialized production is difficult to realize.

The traditional molten salt energy storage has another technical approach that: the single storage tank is adopted for heat storage, the single storage tank has the technical problem of an inclined temperature layer which is difficult to overcome, and the inclined temperature layer with complex temperature distribution exists between the cold fused salt at the lower part of the tank body and the hot fused salt at the upper part of the tank body, so that the control difficulty of the fused salt heat exchange process is increased, high-grade heat energy is correspondingly reduced, and particularly, the single storage tank technology is not suitable for the technical requirement of long-term energy storage.

The strategic goals of carbon peak reaching and carbon neutralization are provided, so that the development of future green energy in China is pointed, particularly, the future renewable energy is gradually changed from a secondary role to a main role in the energy field in China, the advantages of the 'electric-heat-electric' technical mode are gradually shown, and the 'electric-heat-electric' technical mode based on the long-time energy storage technology is necessary to be timely launched.

In fact, the technology of fused salt energy storage heat utilization is not difficult from the basic principle, and the key is whether the economy, safety, reliability, reproducibility and mass popularization of the whole fused salt energy storage system are provided or not, which is the key whether the technology is provided with large-scale popularization and application.

Disclosure of Invention

In order to solve the problems in the background art, the utility model provides a fused salt storage tank and a fused salt electric heat accumulation long-term energy storage device, which can directly replace the existing coal-fired and gas-fired industrial steam boiler, thereby promoting the centralized air supply and heat supply through the fused salt heat accumulation in the industrial park; meanwhile, after the fused salt electric heat storage long-term energy storage device disclosed by the invention is combined with a supercritical carbon dioxide generator set, a novel high-efficiency 'electricity-heat-electricity' technical mode is generated, and the fused salt electric heat storage long-term energy storage device can replace the existing pumped storage power station and chemical energy storage station and becomes a large-capacity long-term energy storage technology.

Meanwhile, the problem of flexibility of traditional heat energy storage application is solved, the technology has the advantages of safety, economy, flexibility, strong adjusting capacity, short construction period, low site selection requirement, flexible construction scale and the like, and a brand-new application scene is opened in the fields of industrial steam, residential heating and heat supply and electricity-heat-electricity energy storage by the long-time molten salt electric heat storage technology.

In order to achieve the above object, the utility model adopts the following technical scheme: a molten salt storage tank is characterized in that a molten salt output branch pipe is arranged at the bottom of the molten salt storage tank, an outer port of the molten salt output branch pipe is a first molten salt outlet, an outlet shutoff valve is arranged at an inner port of the molten salt output branch pipe, a molten salt backflow branch pipe extending into the bottom of the storage tank from the upper portion of the molten salt storage tank is arranged on the molten salt storage tank, an outer end of the molten salt backflow branch pipe is a first molten salt inlet, the first molten salt inlet is located above a molten salt liquid level line, and an inlet shutoff valve is arranged at an inner port of the molten salt backflow branch pipe; export shutoff valve and import shutoff valve structure the same, from up being disk seat, valve clack, connection skeleton, valve rod, electric controller down in proper order, wherein, this disk seat with fused salt output branch pipe or fused salt backward flow branch pipe's inner port intercommunication, the valve rod is perpendicular form setting and its bottom through this connection skeleton and valve clack equipment as an organic whole, the upper end of valve rod then stretches out above the fused salt liquid level control line and the top sets up this electric controller, the last motor part of this electric controller sets up outside the top of fused salt storage tank, can drive the valve rod and reciprocate in order to realize the opening and closing of export shutoff valve and import shutoff valve. In the traditional fused salt energy storage technology, the electronic fused salt valve is the more difficult key spare part of making up to decide, especially under the ultra-temperature condition more than 700 ℃, the temperature toleration, the leakproofness, the heat insulating ability of traditional electronic fused salt valve all face very big technical problem, the cost is high and the manufacturing degree of difficulty is very big, reveal easily in the operation process, the heat loss is big, freeze stifled easily, life is short, the maintenance is changed difficultly and need shut down and overhaul, it is great to shut down its economic cost of overhaul every time, especially, in case the valve freezes stifled, can cause whole system irreversible damage even. The molten salt shut-off valve is creatively arranged in the molten salt storage tank and is arranged at the molten salt outlet and the molten salt inlet, the valve rod of the valve is higher than the molten salt liquid level, the shut-off valve is changed into the normal pressure shut-off valve in the molten salt storage tank, the sealing problem of the valve rod is avoided, the freezing and blocking problem of the valve is avoided, no large part needs heat preservation, the processing and the manufacturing are easy, other parts except an electric controller at the top of the valve almost do not need special maintenance, and the service life of the valve is greatly prolonged. Generally, the overall size of the molten salt storage tank product is controlled within the size range allowed by highway transportation regulations, so that the molten salt storage tank can be produced in a large-scale factory, standardized and modularized manner, the manufacturing cost and the manufacturing difficulty are greatly reduced, the product quality is guaranteed, and the production period is greatly shortened. Typically, the top cover of a molten salt storage tank is removable to facilitate routine maintenance and service of the interior of the storage tank. Generally, this valve rod adopts the seamless nonrust steel pipe of finish draw, can effectively reduce valve rod weight, simultaneously, is provided with a plurality of through-holes on pipy valve rod, and the fused salt of being convenient for enters, reduces the volume that the valve rod occupy.

Furthermore, a guide rod is arranged at the center of the bottom of the valve seat, a guide sleeve matched with the guide rod is arranged at the center of the bottom surface of the valve clack, and the precise matching of the guide rod and the valve clack ensures the opening and closing matching of the valve seat and the valve clack when the valve rod moves up and down; the connecting framework is a universal coupling. Usually, such design can effectively guarantee the leakproofness and the convenience that disk seat and valve clack opened and closed, especially to the valve of overlength valve rod, connects through a universal coupling between valve rod and the valve clack, will greatly guarantee the horizontal sealing cooperation of valve clack and disk seat, has avoided the influence of the central deviation that long valve rod caused to valve clack and disk seat sealing fit degree.

Furthermore, a horizontal cover plate is arranged on a molten salt liquid level line set by the molten salt storage tank, two through holes for the valve rod to pass through are formed in the cover plate, a limiting block with the diameter larger than that of the valve rod is arranged at the top end of the valve rod, a compression spring is arranged on the section of the valve rod between the cover plate and the limiting block, a groove is formed in the upper portion of the limiting block, a heat insulation pad is arranged in the groove, the electric controller is an electric push rod, the top end of the push rod of the electric push rod is abutted to the heat insulation pad, when the push rod of the electric push rod extends, the push rod compresses through the compression spring to enable the valve rod to move downwards to achieve tight joint matching of the valve clack and the valve seat, namely the shut-off valve is closed at the moment, when the electric push rod retracts, the elastic force of the compression spring directly jacks up the valve rod, and the shut-off valve is opened at the moment. In the invention, the electric push rod at the top of the valve rod is not mechanically connected with the valve rod, and the abutting part of the top of the valve rod and the electric push rod is isolated by adopting a heat insulation pad, so that heat is blocked from being transferred to the electric push rod, and the heat loss is effectively reduced; the valve rod, the valve clack, the connecting framework and the like are supported by the compression spring arranged, and the shut-off valve is normally opened under the condition that the electric push rod does not act. When the elasticity of the compression spring is adjusted to a proper value, the requirement on the rated thrust of the electric push rod can be reduced, so that the rated power of the electric push rod can be as small as possible, unnecessary parasitic power consumption is reduced, and generally, the rated power of the electric push rod is only low hundreds of watts; typically, the upper surface of the cover sheet is coated with a thermal barrier coating.

Furthermore, a plurality of electric heating pipes are arranged in the molten salt storage tank, and the electric heating pipes are of single-end flange type structures; the rated voltage of the electric heating pipe is 6.6KV or 10 KV. Through directly setting up electric heating pipe in fused salt storage tank inside, carry out static heating to the fused salt, compare the outer dedicated fused salt heater heating methods of traditional storage tank, not only practiced thrift investment cost, reduced the heat loss among the fused salt flow heating process moreover, improve whole efficiency. Particularly, the high-voltage electric heating is adopted, the electric-heat conversion rate of the high-voltage electric heating exceeds 98%, a large capital investment of a transformer and the like is saved, and the electric-heat conversion rate is improved by at least three percentage points compared with that of the traditional low-voltage electric heating.

A long-time energy storage device of fused salt electric heat accumulation comprises fused salt storage tanks, fused salt, a fused salt output main pipe, a fused salt backflow main pipe, a fused salt pump station, a fused salt heat extractor and an electric control system, and is characterized in that the fused salt storage tanks are characterized in that the number of the fused salt storage tanks is more than three, one of the fused salt storage tanks is ensured to be empty, outlet shutoff valves in the empty fused salt storage tank are in a closed state, inlet shutoff valves in the empty fused salt storage tank are in an open state, the other fused salt storage tanks are filled with the fused salt, a first fused salt outlet on each fused salt storage tank is connected to the fused salt output main pipe, and a first fused salt inlet on each fused salt storage tank is connected to the fused salt backflow main pipe; the molten salt pump station comprises a containing tank and a molten salt pump arranged in the containing tank, wherein the total height of the containing tank is not lower than that of the molten salt storage tank, so that the motor installation position on the molten salt pump is always above the molten salt liquid level line, a molten salt main inlet is arranged at the bottom of the containing tank, the molten salt main inlet is connected with the molten salt output main pipe, and the molten salt pump is provided with a molten salt main outlet; the molten salt heat collector is provided with a second molten salt inlet, a second molten salt outlet, a heat taking medium inlet and a heat taking medium outlet, wherein the second molten salt inlet is connected with the molten salt main outlet, and the second molten salt outlet is connected with the molten salt reflux main pipe; the electric control system has linkage control relation with the electric heating pipe, the molten salt pump, the outlet shutoff valve and the inlet shutoff valve in each molten salt storage tank. In general, in the heat storage mode of the traditional double storage tanks, namely one hot molten salt storage tank and one cold molten salt storage tank, the empty storage tank accounts for 50%, while in the invention, at least three or more molten salt storage tanks are adopted, the more the quantity of the molten salt storage tanks is, the less the empty storage tank accounts for, and the fund occupied by the molten salt storage tank is greatly saved. By adopting the multi-storage-tank mode, the size of the molten salt storage tank can be fixed to be in a single product specification, the size of the single molten salt storage tank can be controlled within a size range specified by the national highway transportation law more conveniently, generally, the diameter of the storage tank is not more than 2.5 meters, and the height of the storage tank is not more than 14 meters, so that the molten salt storage tank can be produced in batch standardized industrial production, and meanwhile, the energy storage capacity of the long-term energy storage device can be flexibly expanded easily. On the other hand, in the whole set of long-time energy storage device, only one molten salt pump is needed, all equipment in the system shares the molten salt pump, a slender cylindrical containing tank is ingeniously configured for the molten salt pump, and the lift of the molten salt pump is almost equal to the height of a molten salt storage tank, so that the rated power of a motor of the molten salt pump can be reduced, and parasitic power consumption is reduced. And the holding tank that matches with the molten salt pump is a miniature salt dredging tank more, can accept the fused salt that flows backwards in the fused salt heat collector when the molten salt pump shuts down, has done the purpose of dredging salt in equipment and the pipeline when shutting down, and the fused salt of in time evacuation stops the fused salt and is detained in fused salt heat collector and pipeline and takes place to freeze stifled, has saved the salt dredging tank system of standard matching among the two storage tank fused salt energy storage systems of tradition, further practices thrift the fund input.

When the long-term energy storage device is in an electric heat storage working state, the inlet shutoff valve and the outlet shutoff valve on one empty molten salt storage tank and the other molten salt storage tanks filled with molten salt are both in a closed state, at the moment, the electric heating pipes in the empty molten salt storage tank do not generate heat, the molten salt in the other molten salt storage tanks filled with molten salt is statically heated to a set upper temperature limit by the electric heating pipes, and a complete molten salt electric heat storage process is completed.

When the long-term energy storage device is in a heat release working state, the outlet shutoff valve on one empty molten salt storage tank is in a closed state, the inlet shutoff valve on the other molten salt storage tanks filled with molten salt is in a closed state, only one outlet shutoff valve on one molten salt storage tank waiting to be evacuated by the molten salt pump is opened, at the moment, the heated molten salt is pumped into the molten salt heat extractor through the molten salt pump to release heat, the released molten salt flows back into the empty molten salt storage tank through the molten salt backflow header pipe until all the molten salt in the molten salt storage tank is poured into the empty molten salt storage tank, at the moment, the molten salt storage tank becomes a new empty molten salt storage tank, so that the other molten salt storage tanks filled with molten salt are emptied in turn to complete a complete molten salt heat release cycle, and in each molten salt heat release process, the molten salt storage tank which is not fixed is empty, each molten salt storage tank filled with molten salt can experience one empty tank, the original empty molten salt storage tank can be filled with the molten salt pumped by other storage tanks, and then the next round of electric heat storage process is carried out after one round of heat release, so that the heat storage-heat release-heat storage cycle is continuous. Generally, the molten salt is a two-component mixed molten salt consisting of 60% of sodium nitrate and 40% of potassium nitrate; or three-component mixed molten salt consisting of 53 percent of potassium nitrate, 40 percent of sodium nitrite and 7 percent of sodium nitrate; or a chloride mixture prepared by purifying and purifying three components of sodium chloride, potassium chloride and calcium chloride according to a certain proportion, wherein the oxygen content of the mixture is controlled to be less than 300 ppm.

Furthermore, the total number of the molten salt storage tanks is a multiple of two, and the molten salt storage tanks are divided into two rows which are arranged in a matrix shape; the molten salt output main pipe is arranged at the middle near bottom of two rows of molten salt storage tanks, the molten salt return main pipe is arranged at the middle near top of the two rows of molten salt storage tanks, the molten salt output main pipe and the molten salt return main pipe are welded into a whole by a plurality of tee joint or four-way welded pipe joints with uniform specifications and segmented molten salt pipe short joints with U-shaped joints, a first molten salt outlet on each molten salt storage tank is connected with a corresponding tee joint or four-way welded pipe joint on the molten salt output main pipe in a welding mode, and a first molten salt inlet on each molten salt storage tank is connected with a corresponding tee joint or four-way welded pipe joint on the molten salt return main pipe in a welding mode; each molten salt storage tank is provided with a certain space above a set molten salt liquid level line, two adjacent spaces are communicated through a short connecting pipe, and the short connecting pipe enables the space at the top in the molten salt storage tank to be communicated so as to balance the air pressure in each molten salt storage tank; the lower parts of two adjacent molten salt storage tanks, which are close to the set molten salt liquid level line, are communicated through a short connecting pipe, and the upper parts in the molten salt storage tanks are mutually communicated through the short connecting pipe, so that the molten salt liquid level height in each molten salt storage tank is balanced; the middle section of the short connecting pipe is provided with a corrugated expansion joint; connect all fused salt storage tanks, fused salt output house steward, fused salt backward flow house steward and fused salt pump station as an organic whole through the welding mode and wholly set up in the heat preservation casing of a rectangular trough-shaped, the top of this heat preservation casing is provided with the heat preservation lid, only the motor that motor and this fused salt pump top on this heat preservation lid exposes outside, simultaneously, the fused salt total export on this fused salt pump and the outer interface of fused salt backward flow house steward all stretch out heat preservation casing's a lateral wall and with the fused salt heat extractor connect. Generally, the design of the invention further improves the standardization and modularization degree of equipment such as a molten salt storage tank and various parts, so that each three-way or four-way welded pipe fitting can be unified in specification and standard, the condition that no sealing connection point exists below the molten salt liquid level line in the heat insulation shell is ensured, the welding, fixing and sealing are adopted, and any leakage possibility is avoided. And all the fused salt pipelines are provided with U-shaped expansion joints or corrugated expansion joints, so that the influence of thermal stress on welding positions is eliminated. The molten salt expansion spaces reserved at the upper parts of all the molten salt storage tanks are communicated with each other through a short connecting pipe with a corrugated joint in the middle, and the hollow molten salt storage tank is filled with inert gas. The motor on the molten salt pump is usually a variable frequency motor.

Further, the installation heights of the molten salt heat collector, the second molten salt outlet and the second molten salt inlet on the molten salt heat collector exceed the total molten salt outlet height on the molten salt pump, the installation heights of the molten salt backflow header pipe and the first molten salt inlet exceed the liquid level height of molten salt in the molten salt storage tank, and the molten salt backflow header pipe has downward inclination towards the first molten salt inlet. Usually, such design has guaranteed the molten salt pump stop work time, and the molten salt in the molten salt heat collector and the molten salt in the molten salt backward flow total pipe are automatic to flow back in the molten salt storage tank or in the molten salt pump holds jar, has eliminated because of the system shut down when the molten salt is detained and is frozen stifled because of the temperature reduction in molten salt heat collector or molten salt backward flow total pipe, simultaneously, compares with traditional two storage tank technologies, need not additionally to set up again and dredge the salt jar system, has further practiced thrift the capital investment.

Furthermore, the outer layer of the heat-insulating shell is of a rectangular groove-shaped reinforced concrete structure, heat-insulating layers are arranged on the inner bottom and four inner vertical surfaces of the heat-insulating shell, high-temperature-resistant heat-insulating bricks are laid on the heat-insulating layers at the bottom, and the molten salt storage tank and the molten salt pump station are both placed on the heat-insulating bricks; a high-temperature-resistant heat-insulating coating layer is coated on the outer surfaces of all the metal tank bodies and the pipelines in the heat-insulating shell, and high-temperature-resistant solid particle heat storage materials are filled in gaps of the heat-insulating shell. Generally, the design life of the fused salt long-term energy storage device is more than 30 years, and the requirement on safety is extremely high, so the fused salt long-term energy storage device adopts the outer layer design of the reinforced concrete, the hazard possibility caused by accidental leakage of the fused salt is reduced to the minimum, the safety is improved, although the cost of the heat insulation outer layer is improved due to the adoption of the concrete, the internal heat insulation layer is arranged on the inner wall of the outer layer of the reinforced concrete, the area of the heat insulation layer is reduced by a plurality of areas compared with the heat insulation of each fused salt storage tank and each fused salt pipeline, and meanwhile, the difficulty of heat insulation construction is greatly reduced; solid particle heat storage materials are filled in gaps outside the molten salt storage tank, the accommodating tank and the molten salt pipeline, so that the total heat storage capacity is increased, the heat preservation and heat tracing effects on the molten salt in the molten salt storage tank or the molten salt pipeline are achieved, particularly, a molten salt output main pipe at the lower part of the storage tank is integrally buried in the solid particle heat storage materials, an electric tracing band does not need to be additionally arranged on the outer surface of the molten salt output main pipe, the cost is further saved, and the parasitic power consumption is reduced; on the other hand, the outer layer of the heat-insulating shell of the reinforced concrete is enough to bear the outward extrusion force from the inside, and the whole molten salt storage tank is wrapped by the solid particle heat storage material, so that the wall thickness of the molten salt storage tank can be reduced, and the whole cost of the molten salt storage tank can be correspondingly reduced; typically, the solid particulate heat storage material is silicon carbide particles or sand particles or magnesium based inorganic particles. In a word, the safety, the economy, the heat preservation performance and the heat storage capacity of the reinforced concrete heat-preservation outer layer are greatly improved by adding the solid particle heat storage material.

Further, this long-term energy memory of fused salt electricity heat accumulation still includes an independent fused salt electric heater, and this independent fused salt electric heater sets up the fused salt pump station with the fused salt heat collector between, and there is a fused salt branch pipe intercommunication fused salt output house steward and fused salt backward flow house steward, and be provided with a stop valve on this fused salt branch pipe, like this, constitute a little circulation circuit by this fused salt pump station, independent fused salt electric heater, fused salt heat collector, fused salt branch pipe and stop valve. The design mainly aims at the application scene of utilizing valley electricity to store energy, generally, about 8 hours of 24 hours per day is the electricity utilization valley period, the electricity price at the time is very low, and the peak load shifting effect of a power grid can be achieved by adopting the energy storage at the time, and great economic benefit is generated on the utilization of heat energy; the heat energy is generally used in 24 hours all day time, so in order to reduce the energy storage scale, the set energy storage only supplies the heat energy requirement in the off-valley electricity time period, about 16 hours off-valley electricity time, when the off-valley electricity time period comes, the previously stored heat energy is released and enters the energy storage stage again in the off-valley electricity time period, and the energy supply in the off-valley electricity time period adopts an independent molten salt electric heater to directly supply heat, so that the stage of heat storage is omitted, the energy storage scale of 8 hours is reduced, the off-valley electricity time period directly supplies energy to save more energy, meanwhile, the long-time energy storage device can fully enter the energy storage working state again, and the energy supply in the 8 hours off-valley electricity time period is completed by the small circulation loop. Usually, the molten salt heat collector is actually a molten salt steam generator, and is dedicated to supply steam to the user end, and if a platen heat exchanger is connected behind the steam generator, the user end can be subjected to heating service.

Further, the long-time energy storage device for fused salt electric heat accumulation further comprises a set of supercritical carbon dioxide generator set, the supercritical carbon dioxide generator set comprises a generator, a turbine, a secondary compressor, a primary compressor, a precooling or condenser, a low-temperature heat regenerator, a high-temperature heat regenerator and a supercritical carbon dioxide conveying pipeline, and a complete supercritical carbon dioxide Brayton cycle power generation system is formed by connecting the supercritical carbon dioxide conveying pipeline with a heat taking medium outlet and a heat taking medium inlet on a fused salt heat collector. The long-term energy storage device is combined with a supercritical carbon dioxide generator set, the novel efficient 'electricity-heat-electricity' technical mode is a novel efficient 'electricity-heat-electricity' technical mode, the 'electricity-heat-electricity' technical mode is an unstable and discontinuous renewable energy source and electric power for the application scene, particularly wind power and photovoltaic electric power are unstable and low in quality, the photo-thermal power generation investment cost is high, the sun is not always hung in the sky, and the defects of solar thermal power generation, wind power and photovoltaic can be fundamentally overcome only by exerting the advantages of the solar thermal power generation, the wind power generation and the photovoltaic generation and avoiding the harm, so that the ultimate goal of replacing fossil energy with the renewable energy is finally achieved. The combination point of the energy-saving energy storage device and the energy-saving energy storage device is realized by electric heating and heat storage, the energy efficiency of the long-term energy storage device and the energy efficiency of the generator set are key points in the technical mode, the energy efficiency problem of the long-term energy storage device is effectively solved, the total energy efficiency of electric-heat conversion is nearly more than 98%, the technology of supercritical carbon dioxide power generation is about to be commercialized, the power generation energy efficiency is more than 50%, and the advantages of the electric-heat-electric technical mode are gradually shown. The long-term energy storage device is particularly suitable for the power generation requirement of small supercritical carbon dioxide of about 10 MW.

The utility model discloses compare in traditional fused salt heat-retaining heat utilization equipment, have compact structure, the system is simple, the heat-retaining is with low costs, exothermic efficiency is high, the system heat waste is little, electric heat and thermoelectric conversion efficiency are all very high, can realize the production of modularization, standardization, batchization, batch production, possess security, economic nature, flexibility, still possess characteristics such as regulating power is strong, construction period is short, the addressing requires to hang down and the construction scale is nimble.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts. The drawings are provided for reference and illustration purposes only and are not intended to limit the present disclosure.

FIG. 1 is a schematic structural diagram of a molten salt storage tank provided by the present invention;

fig. 2 is an enlarged view of a portion of the top of fig. 1 in accordance with the present invention;

fig. 3 is an enlarged view of a portion of the shut-off valve of the bottom of fig. 1 provided by the present invention;

FIG. 4 is a schematic structural view of a molten salt storage tank with an electric heating tube provided by the present invention;

fig. 5 is an enlarged top schematic view of fig. 4 provided by the present invention;

fig. 6 is an enlarged schematic structural view of the bottom of fig. 4 provided by the present invention;

FIG. 7 is a schematic structural view of a long-term energy storage device for molten salt electric heat accumulation provided by the present invention;

fig. 8 is a top view corresponding to fig. 7 provided by the present invention;

FIG. 9 is a schematic structural view of the integrated heat preservation of the long-term energy storage device of molten salt electric heat storage except for the molten salt heat collector provided by the utility model;

fig. 10 is a top view of fig. 9 with the top insulating cover removed, in accordance with the present invention;

FIG. 11 is a schematic structural diagram of a molten salt pump station provided by the present invention;

FIG. 12 is a schematic structural view of a molten salt outlet header and a molten salt return header provided by the present invention;

fig. 13 is a schematic structural view of the long-term energy storage device with an independent molten salt heater added in the molten salt electric heat storage provided by the utility model;

fig. 14 is a schematic structural diagram of the long-term energy storage device with the additional set of supercritical carbon dioxide generator set for molten salt electric heat storage provided by the utility model.

The reference numbers are as follows:

the molten salt heating device comprises a molten salt storage tank 1, a molten salt output branch pipe 2, a first molten salt outlet 3, an outlet shutoff valve 4, a molten salt backflow branch pipe 5, a first molten salt inlet 6, an inlet shutoff valve 7, a valve seat 8, a guide rod 8a, a valve clack 9, a guide sleeve 9a, a connecting framework 10, a valve rod 11, an electric controller 12, a motor 12a, a cover plate 13, a through hole 14, a limiting block 15, a groove 15a, a compression spring 16, a heat insulation pad 17, an electric heating pipe 18, an electric heating pipe installation opening 19, molten salt 20, a molten salt output main pipe 21, a molten salt backflow main pipe 22, a molten salt pump station 23, a containing tank 23a, a molten salt pump 23b, a molten salt total inlet 23c, a molten salt total outlet 23d, a molten salt heat collector 24, a second molten salt inlet 24a, a second molten salt outlet 24b, a heat collecting medium inlet 24c, a heat collecting medium outlet 24d, an electric control system 25, a short connecting pipe 26, a heat insulation shell 27, an outer layer 27a, a, The heat insulation layer 27b, the heat insulation bricks 27c, the heat insulation cover 28, the heat insulation coating layer 29, the solid particle heat storage material 30, the independent molten salt electric heater 31, the molten salt branch pipe 32, the stop valve 33, the supercritical carbon dioxide generator set 34, the generator 34a, the turbine 34b, the secondary compressor 34c, the primary compressor 34d, the precooling or condenser 34e, the low-temperature heat regenerator 34f, the high-temperature heat regenerator 34g and the supercritical carbon dioxide conveying pipeline 34 h.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Example 1:

as shown in fig. 1, fig. 2 and fig. 3, a molten salt storage tank 1 is provided with a molten salt output branch pipe 2 near the bottom, an external port of the molten salt output branch pipe 2 is a first molten salt outlet 3, and an internal port thereof is provided with an outlet shut-off valve 4; this fused salt storage tank 1 is provided with and stretches into the fused salt backward flow branch pipe 5 of storage tank bottom from upper portion, and the outer end of this fused salt backward flow branch pipe 5 is first fused salt import 6, and this first fused salt import 6 is on the fused salt liquid level line, and the inner port department of this fused salt backward flow branch pipe 5 is provided with an import shutoff valve 7.

Outlet shut-off valve 4 is the same with import shut-off valve 7 structure, from up being disk seat 8 down in proper order, valve clack 9, connect skeleton 10, valve rod 11, electric controller 12, wherein, this disk seat 8 and this fused salt output branch pipe 2 or the interior port intercommunication of fused salt backward flow branch pipe 5, valve rod 11 is vertical form setting and its bottom is as an organic whole through this connection skeleton 10 and valve clack 9 equipment, the upper end of valve rod 11 then stretches out above the fused salt liquid level control line and the top sets up this electric controller 12, the motor 12a part on this electric controller 12 sets up outside fused salt storage tank 1's top, can drive valve rod 11 and reciprocate in order to realize the opening and closing of outlet shut-off valve 4 and import shut-off valve 7.

The bottom center department of this disk seat 8 is provided with a guide bar 8a, and 9 bottom surface centers of valve clack department is provided with the guide sleeve 9a that matches with this guide bar, and disk seat 8 and valve clack 9's the cooperation that opens and shuts when valve rod 11 reciprocated have been guaranteed in accurate cooperation between them.

In this embodiment, the connecting frame 10 is a universal joint.

A horizontal cover plate 13 is further arranged on the molten salt liquid level line set by the molten salt storage tank 1, two through holes 14 for the valve rods to pass through are arranged on the cover plate 13, a limiting block 15 with the diameter larger than that of the valve rods 11 is arranged at the top end of the valve rods 11, a compression spring 16 is arranged on the section of the valve rods between the cover plate 13 and the limiting block 15, a groove 15a is arranged at the upper part of the limiting block 15, and a heat insulation pad 17 is arranged in the groove 15 a.

In this embodiment, the electric controller 12 is an electric push rod, the top end of the push rod abuts against the heat insulation pad 17, when the push rod of the electric push rod extends, the push rod compresses the compression spring 16 to make the valve rod 11 move downwards to realize the tight fit of the valve flap 9 and the valve seat 8, that is, the outlet shutoff valve 4 or the inlet shutoff valve 7 is closed at this time, when the electric push rod retracts, the elastic force of the compression spring 16 directly jacks up the valve rod 11, and at this time, the outlet shutoff valve 4 or the inlet shutoff valve 7 is opened.

Example 2:

as shown in fig. 4, 5 and 6, a plurality of electric heating pipes 18 are further arranged in the molten salt storage tank 1, a plurality of electric heating pipe mounting ports 19 are further arranged on the cover plate 13, and the electric heating pipes 18 are of a single-head flange type structure and are matched with the electric heating pipe mounting ports 19; the rated voltage of the electric heating tube 18 is 6.6KV or 10 KV.

The rest is the same as embodiment 1, and is not described in detail herein.

Example 3:

as shown in fig. 7, 8, 10, 11 and 12, the long-term molten salt electric heat storage energy storage device comprises ten molten salt storage tanks 1, molten salt 20, a molten salt output main pipe 21, a molten salt return main pipe 22, a molten salt pumping station 23, a molten salt heat collector 24 and an electric control system 25.

In the embodiment, the total number of the molten salt storage tanks 1 is ten, the molten salt storage tanks are divided into two rows, and each row is provided with 5 molten salt storage tanks which are arranged in a matrix shape at equal intervals; the molten salt output main pipe 21 is arranged at the middle near bottom of two rows of molten salt storage tanks 1, the molten salt return main pipe 22 is arranged at the middle near top of two rows of molten salt storage tanks 1, the molten salt output main pipe 21 and the molten salt return main pipe are welded into a whole by a plurality of tee joint or four-way welded pipe joints with uniform specifications and segmented molten salt pipe short joints with U-shaped joints, a first molten salt outlet 3 on each molten salt storage tank 1 is respectively connected with a corresponding tee joint or four-way welded pipe joint on the molten salt output main pipe 21 in a welding mode, and a first molten salt inlet 6 on each molten salt storage tank 1 is respectively connected with a corresponding tee joint or four-way welded pipe joint on the molten salt return main pipe 22 in a welding mode; each molten salt storage tank 1 is provided with a certain space above a set molten salt liquid level line, inert gas is filled in the space, two adjacent spaces are communicated through a short connecting pipe 26, and the short connecting pipe 26 enables the space at the top in the molten salt storage tank 1 to be communicated so as to balance the air pressure in each molten salt storage tank; the lower parts of two adjacent molten salt storage tanks, which are close to the set molten salt liquid level line, are communicated through a short connecting pipe 26, and the uppermost parts in the molten salt storage tanks are mutually communicated through the short connecting pipe 26 so as to balance the molten salt liquid level height in each molten salt storage tank; the middle section of the short connecting pipe 26 is provided with a corrugated expansion joint; connect all fused salt storage tank 1 as an organic whole, fused salt output manifold 21, fused salt backward flow house steward 22 and fused salt pump station 23 through the welding mode and wholly set up in the heat preservation casing 27 of a rectangular trough-like, the top of this heat preservation casing 27 is provided with heat preservation lid 28, only have on this heat preservation lid 28 electric controller 12 go up the motor with the motor at fused salt pump 23b top expose outside, simultaneously, fused salt total outlet 23d and fused salt backward flow house steward 22's on this fused salt pump 23b external tapping all stretch out heat preservation casing 27a lateral wall and with fused salt heat extractor 24 connect.

In this embodiment, the outer layer 27a of the thermal insulation casing 27 is a reinforced concrete structure in a rectangular groove shape, the inner bottom and four inner vertical surfaces of the thermal insulation casing are provided with thermal insulation layers 27b, a high temperature resistant thermal insulation brick 27c is further laid on the thermal insulation layer 27b at the bottom, and the molten salt storage tank 1 and the molten salt pump station 23 are laid on the thermal insulation brick 27 c; a layer of high temperature resistant heat insulation coating layer 29 is coated on the outer surfaces of all the metal tanks and pipelines in the heat insulation shell 27, and the gaps are filled with high temperature resistant solid particle heat storage materials 30.

Wherein, guarantee in ten fused salt storage tanks 1 that a fused salt storage tank is empty and the export shutoff valve 4 in this empty fused salt storage tank is in the closed condition and import shutoff valve 7 is in the open mode, then fill in the nine fused salt storage tanks of remaining have fused salt 20, the first fused salt export 3 on every this fused salt storage tank 1 all inserts this fused salt output main 21, and the first fused salt import 6 on every this fused salt storage tank 1 all inserts this fused salt backward flow house steward 22.

The molten salt pump station 23 comprises a holding tank 23a and a molten salt pump 23b arranged in the holding tank, the overall height of the holding tank 23a is not lower than the height of the molten salt storage tank 1, the bottom of the holding tank 23a is provided with a molten salt total inlet 23c, the molten salt total inlet 23c is connected with the molten salt output main pipe 21, and the molten salt pump 23b is provided with a molten salt total outlet 23 d.

The molten salt heat collector 24 is provided with a second molten salt inlet 24a, a second molten salt outlet 24b, a heat taking medium inlet 24c and a heat taking medium outlet 24d, wherein the second molten salt inlet 24a is connected with the molten salt main outlet 23d, and the second molten salt outlet 24b is connected with the molten salt return manifold 22.

The electric control system 25 and the electric heating pipe 18 in each molten salt storage tank 1, the motor on the molten salt pump 23b, the motor 12a on the outlet shutoff valve 4 and the motor 12a on the inlet shutoff valve 7 have a linkage control relationship, and the control relationship comprises molten salt temperature control, switching on and off of various motors, starting and stopping of electric heating, opening and closing of the shutoff valves and the like.

The long-time energy storage device for the molten salt electric heat storage is provided with the working states of the two, namely the electric heat storage state and the heat release state, and the two states are carried out in a circulating mode in daily life. These two operating states are briefly described below.

1, when the long-term energy storage device is in an electric heat storage working state:

the inlet shutoff valve 4 and the outlet shutoff valve 7 on one empty molten salt storage tank 1 and nine molten salt storage tanks 1 filled with molten salt 20 are both in a closed state, at the moment, the electric heating pipes 18 in the empty molten salt storage tanks 1 do not generate heat, and the molten salt in the nine molten salt storage tanks 1 filled with molten salt 20 is statically heated to a set upper temperature limit by the electric heating pipes 18, so that a complete molten salt electric heat storage process is completed;

2, when the long-term energy storage device is in a heat release working state:

the outlet shut-off valve 4 and the inlet shut-off valve 7 on an empty molten salt storage tank 1 are in a closed state and in an open state, the inlet shutoff valves 7 on the other nine molten salt storage tanks 1 filled with the molten salt 20 are all in a closed state, and only one of the outlet shut-off valves 4 on the molten salt storage tank 1 waiting to be evacuated by the molten salt pump 23b is opened, at this time, the heated molten salt 20 is pumped into the molten salt heat extractor 24 through the molten salt pump 23 to release heat, the molten salt 20 after heat release flows back into the empty molten salt storage tank 1 through the molten salt backflow header pipe 22 until all the molten salt in the molten salt storage tank 1 is poured into the empty molten salt storage tank, the molten salt storage tank 1 becomes a new empty molten salt storage tank 1, so that nine molten salt storage tanks 1 filled with molten salt 20 are emptied in turn to complete a complete molten salt heat release cycle, and then, the next round of electric heat storage process is carried out. In each round of molten salt heat release process, the molten salt storage tank 1 is not fixed to be empty, each molten salt storage tank 1 filled with the molten salt 20 can experience one empty tank, the originally empty molten salt storage tank can be filled with the molten salt pumped by other storage tanks, then, the next round of electric heat storage process is carried out after one round of heat release, and thus the heat storage-heat release-heat storage cycle is continuous.

The installation height of the molten salt heat collector 24 and the second molten salt outlet 24b and the second molten salt inlet 24a on the molten salt heat collector exceeds the height of the total molten salt outlet 23d on the molten salt pump 23b, the installation height of the molten salt reflux header pipe 22 and the first molten salt inlet 6 exceeds the liquid level height of the molten salt in the molten salt storage tank 1, and the molten salt reflux header pipe 22 is installed downwards in a downward inclination mode towards the first molten salt inlet 6. Generally, by adopting the design, when the molten salt pump 23b stops working, the molten salt 20 in the molten salt heat collector 24 and the molten salt in the molten salt reflux main pipe 22 automatically reflux to the molten salt storage tank 1 or the molten salt pump holding tank 23a, and the frozen blockage caused by the temperature reduction when the molten salt 20 stays in the molten salt heat collector 24 or the molten salt reflux main pipe 22 when the system is shut down is eliminated.

Example 4:

as shown in fig. 13, the long-term energy storage device of molten salt electric heat accumulation further includes an independent molten salt electric heater 31, the independent molten salt electric heater 31 is arranged between the molten salt pump station 23 and the molten salt heat extractor 24, a molten salt branch pipe 32 is communicated with the molten salt output main pipe 21 and the molten salt return main pipe 22, and a stop valve 33 is arranged on the molten salt branch pipe 32, so that a small circulation loop is formed by the molten salt pump station 23, the independent molten salt electric heater 31, the molten salt heat extractor 24, the molten salt branch pipe 32 and the stop valve 33.

The rest is the same as embodiment 3, and is not described in detail herein.

Example 5:

as shown in fig. 14, the long-term energy storage device for molten salt electric heat storage further includes a set of supercritical carbon dioxide generator set 34, where the supercritical carbon dioxide generator set 34 includes a generator 34a, a turbine 34b, a secondary compressor 34c, a primary compressor 34d, a pre-cooling or condenser 34e, a low-temperature heat regenerator 34f, a high-temperature heat regenerator 34g, and a supercritical carbon dioxide conveying pipeline 34h, and a complete supercritical carbon dioxide brayton cycle power generation system is formed by connecting the supercritical carbon dioxide conveying pipeline 34h with a heat-taking medium outlet 24d and a heat-taking medium inlet 24c on the molten salt heat collector 24.

The rest is the same as embodiment 3, and is not described in detail herein.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Although the molten salt storage tank, the molten salt output branch pipe, the first molten salt outlet, the outlet shut-off valve, the molten salt backflow branch pipe, the first molten salt inlet, the inlet shut-off valve, the valve seat, the guide rod, the valve clack, the guide sleeve, the connecting framework, the valve rod, the electric controller, the motor, the cover plate, the through hole, the limiting block, the groove, the compression spring, the heat insulation pad, the electric heating pipe mounting opening, the molten salt output main pipe, the molten salt backflow main pipe, the molten salt pump station, the holding tank, the molten salt pump, the molten salt main inlet, the molten salt main outlet, the molten salt heat collector, the second molten salt inlet, the second molten salt outlet, the heat taking medium inlet, the heat taking medium outlet, the electric control system, the short connecting pipe, the heat insulation shell, the outer layer, the heat insulation cover, the heat insulation coating layer, the solid particle heat storage material, the independent molten salt electric heater, the molten salt branch pipe, the stop valve, Supercritical carbon dioxide power generation, turbine, secondary compressor, primary compressor, pre-cooling or condenser, low temperature regenerator, high temperature regenerator, supercritical carbon dioxide transfer line, and the like, but does not exclude the possibility of using other terms, which are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed in a manner that is inconsistent with the spirit of the invention.

Claims (10)

1. A molten salt storage tank is characterized in that a molten salt output branch pipe is arranged near the bottom of the molten salt storage tank, an outer port of the molten salt output branch pipe is a first molten salt outlet, an outlet shutoff valve is arranged at an inner port of the molten salt output branch pipe, a molten salt backflow branch pipe extending into the bottom of the storage tank from the upper portion of the molten salt storage tank is arranged on the molten salt storage tank, the outer end of the molten salt backflow branch pipe is a first molten salt inlet, the first molten salt inlet is located above a molten salt liquid level line, and an inlet shutoff valve is arranged at an inner port of the molten salt backflow branch pipe; export shutoff valve and import shutoff valve structure the same, from up being disk seat, valve clack, connection skeleton, valve rod, electric controller down in proper order, wherein, this disk seat with fused salt output tube or fused salt back flow's inner port intercommunication, the valve rod is vertical form setting and its bottom is as an organic whole through this connection skeleton and valve clack equipment, the upper end of valve rod then stretches out above the fused salt liquid level control line and the top sets up this electric controller, the last motor part of this electric controller sets up outside the top of fused salt storage tank, can drive the valve rod and reciprocate in order to realize the opening and closing of export shutoff valve and import shutoff valve.

2. The molten salt storage tank as claimed in claim 1, wherein a guide rod is arranged at the center of the bottom of the valve seat, a guide sleeve matched with the guide rod is arranged at the center of the bottom surface of the valve clack, and the precise matching of the guide rod and the valve clack ensures the opening and closing matching of the valve seat and the valve clack when the valve rod moves up and down; the connecting framework is a universal coupling.

3. A molten salt storage tank as claimed in claim 1, wherein a horizontal cover plate is provided above the molten salt level set by the molten salt storage tank, the cover plate is provided with two through holes for the valve rod to pass through, the top end of the valve rod is provided with a limit block with the diameter larger than that of the valve rod, the section of the valve rod between the cover plate and the limit block is provided with a compression spring, the upper part of the limiting block is provided with a groove, the groove is internally provided with a heat insulation pad, the electric controller is an electric push rod, the top end of the push rod is abutted against the heat insulation pad, when the push rod of the electric push rod extends, the push force of the push rod enables the compression spring to compress, so that the valve rod moves downwards to realize the tight fit of the valve clack and the valve seat, namely the shut-off valve is closed at the moment, when the electric push rod retracts, the elastic force of the compression spring directly jacks up the valve rod, and the shut-off valve is opened at the moment.

4. The molten salt storage tank as claimed in claim 1, wherein a plurality of electric heating pipes are further arranged in the molten salt storage tank, and the electric heating pipes are of a single-head flange type structure; the rated voltage of the electric heating pipe is 6.6KV or 10 KV.

5. A long-time energy storage device of fused salt electric heat accumulation comprises fused salt storage tanks, fused salt, a fused salt output main pipe, a fused salt backflow main pipe, a fused salt pump station, a fused salt heat extractor and an electric control system, and is characterized in that the fused salt storage tanks are as claimed in claims 1 to 4, the number of the fused salt storage tanks is set to be more than three, one of the fused salt storage tanks is ensured to be empty, an outlet shutoff valve in the empty fused salt storage tank is in a closed state, an inlet shutoff valve in the empty fused salt storage tank is in an open state, the other fused salt storage tanks are filled with the fused salt, a first fused salt outlet on each fused salt storage tank is connected to the fused salt output main pipe, and a first fused salt inlet on each fused salt storage tank is connected to the fused salt backflow main pipe; the molten salt pump station comprises a containing tank and a molten salt pump arranged in the containing tank, the total height of the containing tank is not lower than that of the molten salt storage tank, a molten salt main inlet is formed in the bottom of the containing tank, the molten salt main inlet is connected with the molten salt output main pipe, and the molten salt pump is provided with a molten salt main outlet; the molten salt heat collector is provided with a second molten salt inlet, a second molten salt outlet, a heat taking medium inlet and a heat taking medium outlet, wherein the second molten salt inlet is connected with the molten salt main outlet, and the second molten salt outlet is connected with the molten salt reflux main pipe; the electric control system is in linkage control relation with the electric heating pipe, the molten salt pump, the outlet shutoff valve and the inlet shutoff valve in each molten salt storage tank;

when the long-term energy storage device is in an electric heat storage working state, the inlet shutoff valve and the outlet shutoff valve on one empty molten salt storage tank and the other molten salt storage tanks filled with molten salt are both in a closed state, at the moment, the electric heating pipe in the empty molten salt storage tank does not generate heat, the molten salt in the molten salt storage tanks filled with molten salt is statically heated to a set upper temperature limit by the electric heating pipe, and a complete molten salt electric heat storage process is completed;

when the long-term energy storage device is in a heat release working state, the outlet shutoff valve on an empty molten salt storage tank is in a closed state and the inlet shutoff valve is in an open state, the inlet shutoff valves on the other molten salt storage tanks filled with molten salt are all in a closed state, and only one of the outlet shutoff valves on the molten salt storage tank waiting to be pumped out by the molten salt pump is opened, at this time, the heated molten salt is pumped into the molten salt heat extractor through the molten salt pump to release heat, the molten salt after heat release flows back into the empty molten salt storage tank through the molten salt backflow header pipe until all the molten salt in the molten salt storage tank is poured into the empty molten salt storage tank, the molten salt storage tank becomes a new empty molten salt storage tank, so that the molten salt storage tanks filled with molten salt are emptied in turn to complete a complete molten salt heat release cycle, and then the next round of electric heat storage process is started.

6. The long-term molten salt electric heat storage energy storage device according to claim 5, characterized in that the total number of the molten salt storage tanks is a multiple of two, divided into two rows, and arranged in a matrix; the molten salt output main pipe is arranged at the middle near bottom of the two rows of molten salt storage tanks, the molten salt return main pipe is arranged at the middle near top of the two rows of molten salt storage tanks, the molten salt output main pipe and the molten salt return main pipe are welded into a whole by a plurality of tee joint or four-way welded pipe joints with uniform specifications and segmented molten salt pipes with U-shaped joints in a short connection mode, a first molten salt outlet on each molten salt storage tank is connected with a corresponding tee joint or four-way welded pipe joint on the molten salt output main pipe in a welding mode, and a first molten salt inlet on each molten salt storage tank is connected with a corresponding tee joint or four-way welded pipe joint on the molten salt return main pipe in a welding mode; each molten salt storage tank is provided with a certain space above a set molten salt liquid level line, two adjacent spaces are communicated through a short connecting pipe, and the short connecting pipe enables the space at the top in the molten salt storage tank to be communicated so as to balance the air pressure in each molten salt storage tank; the lower parts of two adjacent molten salt storage tanks, which are close to the set molten salt liquid level line, are communicated through a short connecting pipe, and the uppermost parts in the molten salt storage tanks are mutually communicated through the short connecting pipe, so that the molten salt liquid level height in each molten salt storage tank is balanced; the middle section of the short connecting pipe is provided with a corrugated expansion joint; all fused salt storage tanks, fused salt output house steward, fused salt backward flow house steward and fused salt pump station that link as an organic whole through the welding mode wholly set up in the heat preservation casing of a rectangular trough-like, and the top of this heat preservation casing is provided with the heat preservation lid, should keep warm to cover only the electric controller in claim 1 on the motor with the motor at fused salt pump top expose outside, simultaneously, fused salt total export and fused salt backward flow house steward's external tapping on this fused salt pump all stretch out heat preservation casing one side wall and with the fused salt heat extractor connect.

7. A molten salt electric heat long-time energy storage device according to claim 5 or 6, characterized in that the installation heights of the molten salt heat collector, the second molten salt outlet and the second molten salt inlet on the molten salt heat collector exceed the total molten salt outlet height on the molten salt pump, the installation heights of the molten salt backflow header pipe and the first molten salt inlet exceed the liquid level height of molten salt in the molten salt storage tank, and the molten salt backflow header pipe is installed in a downward inclination manner towards the first molten salt inlet.

8. The molten salt electric heat storage long-time energy storage device according to claim 6, characterized in that the outer layer of the heat preservation shell is a reinforced concrete structure in a rectangular groove shape, heat preservation and insulation layers are respectively arranged on the inner bottom and four inner vertical surfaces of the heat preservation shell, high temperature resistant heat insulation bricks are further laid on the heat preservation and insulation layers on the bottom, and the molten salt storage tank and the molten salt pump station are placed on the heat insulation bricks; a high-temperature-resistant heat-insulating coating layer is coated on the outer surfaces of all the metal tank bodies and the pipelines in the heat-insulating shell, and high-temperature-resistant solid particle heat storage materials are filled in gaps of the heat-insulating shell.

9. The long-term energy storage device of fused salt electric heat accumulation according to claim 5, further comprising an independent fused salt electric heater, wherein the independent fused salt electric heater is arranged between the fused salt pump station and the fused salt heat extractor, a fused salt branch pipe is communicated with the fused salt output main pipe and the fused salt return main pipe, and a stop valve is arranged on the fused salt branch pipe, so that a small circulation loop is formed by the fused salt pump station, the independent fused salt electric heater, the fused salt heat extractor, the fused salt branch pipe and the stop valve.

10. The molten salt electric heat storage long-term energy storage device of claim 5, further comprising a set of supercritical carbon dioxide generator set, wherein the supercritical carbon dioxide generator set comprises a generator, a turbine, a secondary compressor, a primary compressor, a pre-cooling or condenser, a low-temperature heat regenerator, a high-temperature heat regenerator and a supercritical carbon dioxide conveying pipeline, and a complete supercritical carbon dioxide Brayton cycle power generation system is formed by connecting the supercritical carbon dioxide conveying pipeline with a heat taking medium outlet and a heat taking medium inlet on a molten salt heat remover.

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