JP5203642B2 - Superconducting power transmission cable and system - Google Patents

Description

  The present invention relates to a highly efficient cooling technique for a superconducting power transmission cable using slush nitrogen in which fine solid nitrogen and liquid nitrogen are uniformly mixed.

In recent years, superconducting transmission cables have been developed and put into practical use as one of the applications of superconducting technology in the power field. This applies a superconductor with zero electric resistance to a power transmission line, and can transmit a large amount of power. Superconductors include metal-based superconductors with liquid helium cooling and oxide-based superconductors with liquid nitrogen cooling. Among them, high-temperature superconductors using liquid nitrogen as a refrigerant are drawing attention. It's getting on.
As an example of a general superconducting power transmission cable, FIG. 8 shows a schematic diagram of a power transmission cable using a high-temperature superconductor. The superconducting power transmission cable 100 has a structure in which a hollow tube called a former 101 formed of an aluminum material or the like is disposed in a heat insulating tube, and a superconductor 102 and an insulating material 103 are wound around the outer periphery thereof. The heat insulating tube has a vacuum heat insulating structure in which a heat insulating vacuum part 105 is disposed between the inner heat insulating tube 104 and the outer heat insulating tube 106. A liquid refrigerant 107 having a temperature lower than the boiling point is caused to flow in and out of the former 101 to cool the superconductor 102 to form a superconducting state. As the liquid refrigerant 107, liquid nitrogen is mainly used.

Such a superconducting power transmission cable is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 11-43610) and the like.
Patent Document 2 (Japanese Patent Application Laid-Open No. 2001-202837) discloses a superconducting power transmission cable in which two types of refrigerant are filled inside and outside the cable core, and the refrigerant filled inside the cable core is disclosed. Use a refrigerant whose operating temperature change width is larger than the operating temperature change width of the refrigerant filling the outside of the cable core, use a mixture of liquid oxygen and liquid nitrogen as the inner refrigerant, and use liquid as the outer refrigerant. A structure using nitrogen is described. Thus, by using a refrigerant having a large operating temperature change width such as liquid oxygen, one cooling section length can be increased.

And a superconducting power transmission cable forms a cable track via a connection part, and comprises the power transmission cable system which has arrange | positioned the cooling equipment which produces | generates the refrigerant | coolant for superconducting power transmission cable cooling for every cooling section length. The cooling facility is provided with a refrigerator that cools the refrigerant below the critical temperature, and a pump that pumps the cooled refrigerant to the superconducting power transmission cable.
A power transmission cable system including a refrigeration apparatus is disclosed in, for example, Patent Document 3 (Japanese Patent Laid-Open No. 2002-56729). This consists of a refrigeration station consisting of a refrigerator and a pressure pump, and a separate pump pump separately on the cable path. This reduces the limitation on the cooling section length due to the amount of pressure loss. The cooling section can be lengthened.

However, if a method in which the refrigerant flows through the power transmission cable in an opposing manner, the liquid refrigerant inside and outside the former exchanges heat when the cooling section length becomes long, and heat generated in the cable may not be removed. It became clear.
Therefore, in recent years, a method of flowing a liquid refrigerant in the same direction inside and outside the former is considered promising. FIG. 9 shows a power transmission cable system in which liquid nitrogen is flowed in the same direction as a refrigerant. In this system, in the system in which the cooling facilities 110a, 110b,... Are arranged for each cooling section length of the superconducting power transmission cable 100, the liquid nitrogen generated in the cooling facility 110a flows into the superconducting power transmission cable from the upstream end of the superconducting power transmission cable. To be introduced. Within the cable, the liquid nitrogen temperature gradually rises due to heat absorption in the cable, and reaches the downstream end of the cable before reaching the boiling point. The liquid nitrogen that exits the downstream end of the cable is sent to another cable to cool the superconducting power transmission cable further downstream after cooling by the cooling facility 110b.

Japanese Patent Laid-Open No. 11-43610 JP 2001-202837 A JP 2002-56729 A

However, in the system in which the refrigerant flows in the same direction in the superconducting power transmission cable as described above, the liquid nitrogen flowing in the cable is in one direction, so that the refrigerant overflows at the end of the cable. Therefore, when liquid nitrogen is used as the refrigerant, it is conceivable that the liquid nitrogen is discharged into the atmosphere at the final end or diverted to other uses. In this case, it is necessary to constantly generate and replenish liquid nitrogen at the start end, which is costly. Is bulky. In addition, there is a method of always using an even number of superconducting power transmission cables and circulating the refrigerant. However, in this case, even if a trouble occurs in one line, the two lines cannot be used and the efficiency is low. In addition, a method of providing a dedicated return pipe is also conceivable, but in this case, the temperature of the liquid nitrogen in the return pipe rises and bubbles are likely to be generated, which may cause the return pipe to be clogged. Since the loss becomes very large, an increase in the size or cost of the pump is inevitable.
Accordingly, the present invention provides a superconducting power transmission cable that can circulate and use a refrigerant in one superconducting power transmission cable and can efficiently cool a high-temperature superconductor, and a system thereof, in view of the above-described problems of the prior art. The purpose is to do.

Therefore, in order to solve this problem, the present invention provides:
In a superconducting power transmission cable comprising a high-temperature superconductor, two or more refrigerant paths composed of a refrigerant forward path and a refrigerant return path for flowing a refrigerant that cools the superconductor, and a heat insulating pipe that encloses the superconductor and the refrigerant path ,
The refrigerant flowing through at least the refrigerant forward path, characterized in that the slush nitrogen which contains a fine solid nitrogen to liquid nitrogen.

The slush nitrogen is a slurry of a mixture of atomized solid nitrogen and liquid nitrogen. By using this slush nitrogen, the temperature is lower than that of liquid nitrogen, and a low temperature (63K) near the triple point of nitrogen can be maintained. Further, since the solid latent heat of fusion can be used, the heat load absorption capacity is superior to liquid nitrogen. Furthermore, the temperature can be kept constant as long as the solid content exists, and even if slush nitrogen is flowed in and out of the superconductor, heat generated in the cable is efficiently carried outside the cable, and Can be concentrated on one end side. Furthermore, even if there is no solid content in the slush nitrogen, the amount of heat corresponding to the temperature increase from 63 K to the boiling point can be used, so that cooling can be performed with a smaller amount than with simple liquid nitrogen cooling.
Thus, by using slush nitrogen as a refrigerant, high-efficiency cooling of the superconducting power transmission cable becomes possible.

Further, it is preferable that the refrigerant flowing in the refrigerant forward path is slush nitrogen and the refrigerant flowing in the refrigerant return path is mainly liquid nitrogen. This is suitable when the cooling section length of the superconducting power transmission cable is long, it is possible to maintain the entire cable to 63K if there is slush nitrogen only forward. In this case, the refrigerant return path is mainly liquid nitrogen, but the heat generated in the cable is cooled by the slush nitrogen in the refrigerant forward path, and even if the liquid nitrogen is heated and the temperature rises, the heat will eventually be the lowest. It will be absorbed by slush nitrogen, which will not adversely affect cable cooling.
Furthermore, any refrigerant in the two refrigerant paths may be slush nitrogen. This is suitable when the length of the cooling section of the superconducting power transmission cable is relatively short or a sudden heat load is assumed, and can be maintained below 63K over the entire length of the cable according to the present invention. Cooling is possible.

In the superconducting power transmission cable in which the superconductor is wound around the outer periphery of the former,
The refrigerant forward path is formed inside the former, a tubular heat radiation shield is provided on the outer periphery of the superconductor via a heat insulation vacuum layer, and the heat conduction vacuum layer is parallel to the superconductor via the heat insulation vacuum layer. wherein the refrigerant condensate line are provided.
Thus, by providing a heat radiation shield, heat penetration from the outside can be prevented, and efficient cooling can be achieved.
Furthermore, in the superconducting power transmission cable in which the superconductor is wound around the outer periphery of the former,
Wherein said outgoing coolant passage inside the former is formed, characterized in that the coolant recovery path of the tubular is provided on the outer periphery of the superconductor via a heat-insulating vacuum layer.
In this way, by using the refrigerant return path itself as a heat radiation shield, it is possible to perform cooling with a simple structure and efficient.

Further, the above superconducting transmission cable, means for generating a pre-Symbol refrigerant, a cooling equipment and means for pumping the coolant into the superconducting power transmission cable, the superconducting power transmission cable systems with,
The refrigerant generating means has a low-temperature container filled with liquid nitrogen, and an ejector that injects a low-temperature working fluid having a pressure higher than the space in the container into the container to suck out the liquid nitrogen;
In the refrigerant generating means, the liquid nitrogen sucked and ejected by the low temperature working fluid is cooled by the low temperature working fluid and falls as fine solid nitrogen, and is mixed with the liquid nitrogen to generate slush nitrogen. The slush nitrogen is introduced into the refrigerant path by the pumping means.
Thus, by using the refrigerant generating means, the particle diameter of solid nitrogen in slush nitrogen can be made relatively uniform and small, and pressure loss can be reduced when flowing through the refrigerant path of the superconducting power transmission cable. Can do.

Furthermore, the above superconducting transmission cable, means for generating a pre-Symbol refrigerant, a cooling equipment and means for pumping the coolant into the superconducting power transmission cable, the superconducting power transmission cable systems with,
The refrigerant generating means has a heat insulating container filled with liquid nitrogen, a pressure reducing means for reducing the pressure inside the heat insulating container, and a stirring means for stirring the inside of the heat insulating container,
In the refrigerant generating means, the liquid nitrogen in the heat insulating container is depressurized by the pressure reducing means to lower the temperature, reach the triple point to generate solid nitrogen, and the solid nitrogen atomized by stirring by the stirring means The slush nitrogen is produced by mixing with liquid nitrogen, and the slush nitrogen is introduced into the refrigerant path by the pumping means.
According to the present invention, since solid nitrogen can be generated without using other refrigerants, an apparatus with a simple structure and reduced size without requiring large equipment such as a recompressor for other refrigerants. Can produce slush nitrogen.

Furthermore, the above superconducting transmission cable, means for generating a pre-Symbol refrigerant, a cooling equipment and means for pumping the coolant into the superconducting power transmission cable, the superconducting power transmission cable systems with,
The refrigerant generating means has a container kept under reduced pressure, a nozzle for injecting liquid nitrogen into the container, and a stirrer for stirring the inside of the container;
In the refrigerant generation means, liquid nitrogen droplet particles ejected from the nozzle are evaporated in a reduced-pressure atmosphere, and the droplet particles are solidified by latent heat of vaporization to form solid nitrogen, mixed with the liquid nitrogen and slush nitrogen And the slush nitrogen is introduced into the refrigerant path by the pumping means.
Thus, by using the refrigerant generating means, slush nitrogen can be easily generated with a simple apparatus.

As described above, slush nitrogen is a slurry mixture of atomized solid nitrogen and liquid nitrogen, so when used as a cooling refrigerant, it exhibits a temperature near the melting point of solid nitrogen, Therefore, it wets on the object surface and penetrates into narrow gaps, so that the thermal conductivity is good and the latent heat of melting of solid nitrogen of 25 kJ / kg can be used for cooling. Therefore, compared to the unit mass, there is a cooling effect of 12.5 times or more of the sensible heat of liquid nitrogen, and as long as solid nitrogen exists, the temperature of the refrigerant does not rise above 63K, and superconducting power transmission that is the object of cooling Cable temperature can be kept low.
In addition, even when liquid feeding is stopped, the temperature of the superconducting object can be kept low for a certain time due to solid latent heat, and the reliability of the power transmission cable system is improved.
Furthermore, the temperature can be kept constant as long as the solid content exists, and even if slush nitrogen is flowed in and out of the superconductor, heat generated in the cable is efficiently carried outside the cable, and Can be concentrated on one end side. Furthermore, even if there is no solid content in the slush nitrogen, the amount of heat corresponding to the temperature increase from 63 K to the boiling point can be used, so that cooling can be performed with a smaller amount than with simple liquid nitrogen cooling.
Thus, by using slush nitrogen as a refrigerant, high-efficiency cooling of the superconducting power transmission cable becomes possible.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

Reference example 1

Figure 1 is a block diagram of a superconducting power transmission cable according to participate Reference Example 1, (a) is a side sectional view, (b) is a cross-sectional view.
In FIG. 1, a superconducting power transmission cable 10 includes a former 11, a high-temperature superconductor 12, an insulating layer 13, an inner heat insulating tube 14, and an outer heat insulating tube 15 from the inner peripheral side. The former 11 is preferably made of a material having high thermal conductivity, such as a metal material such as an aluminum tube or a copper tube. The former 11 has a hollow cylindrical shape as shown in the figure, and the inside thereof is used as the refrigerant forward path 20. In addition, it is good also as a structure which arrange | positions a refrigerant | coolant path | route in parallel with the outer side of this former 11 for the former 11 as a solid cylindrical shape.
The superconductor 12 is formed of an oxide-based superconducting material that is in a superconducting state at 77.3 K (−196 ° C.), and preferably a wire formed of an yttrium-based or bismuth-based oxide that is a copper oxide. such as those coated with silver or Gingo gold sheath good. Examples of the superconductor 12 include a structure in which a tape-like or round wire-like superconducting wire is wound around the former 11, and a structure in which the superconducting wire is twisted and wound.
The insulating layer 13 is formed by winding an insulator such as kraft paper or resin.
The inner heat insulating pipes 14 are arranged on the outer peripheral side of the insulating layer 13 so as to be separated from each other by a predetermined interval, and a refrigerant return path 21 is formed in a space between them.
The outer heat insulating tube 15 is disposed on the outer peripheral side of the inner heat insulating tube 14 via a vacuum heat insulating tube (not shown).

This reference example 1 is a configuration suitable for the case where the cooling section length of the superconducting power transmission cable 10 is relatively short or a sudden heat load is assumed. As shown in FIG. 1A, slush nitrogen (SN ₂ ), which is a refrigerant, is introduced into the refrigerant return path 20, and the slush nitrogen is folded at the end of the cable and returns to the cable start end through the refrigerant return path 21. It is like that. Thus, the superconductor 12 can be deeply cooled by flowing the slush nitrogen in and out of the superconductor 12 in an opposing manner. In this case, the superconducting power transmission cable 10 is held at 63K over the entire length.

The slush nitrogen is a slurry of a mixture of atomized solid nitrogen and liquid nitrogen, and its production method is not particularly limited. By using the slush nitrogen, the temperature is lower than that of liquid nitrogen, and a low temperature (63 K) near the triple point of nitrogen can be maintained. Further, since the solid latent heat of fusion can be used, the heat load absorption capacity is superior to liquid nitrogen. Furthermore, the temperature can be kept constant as long as the solid content exists, and even if slush nitrogen is flowed in and out of the superconductor 12, the heat generated in the cable is efficiently carried outside the cable, and It is possible to prevent the refrigerant from concentrating on one end side. Furthermore, even if there is no solid content in the slush nitrogen, the amount of heat corresponding to the temperature increase from 63 K to the boiling point can be used, so that cooling can be performed with a smaller amount than with simple liquid nitrogen cooling.
As described above, by using slush nitrogen as a refrigerant, it is possible to cool the superconducting power transmission cable 10 with high efficiency.

The block diagram of the superconducting power transmission cable which concerns on FIG. 2 at Example 1 of this invention is shown. FIG. 2A is a side sectional view of the superconducting power transmission cable, and FIG. 2B is a sectional view.
Superconducting power transmission cable 10 according to the first embodiment has substantially the same structure as the above-described example 1, the superconducting power transmission cable 10, from the inner periphery side, the former 11, the high-temperature superconductor 12, an insulating layer 13, an inner heat insulating pipe 14 and an outer heat insulating pipe 15, and a refrigerant forward path 20 is formed inside the former 11, and a refrigerant return path 21 is formed between the insulating layer 13 and the inner heat insulating pipe 14. Since each configuration is the same as that of Reference Example 1, description thereof is omitted.
The first embodiment is suitable when the cooling section length of the superconducting power transmission cable 10 is long, as shown in FIG. 2 (a), introducing a slush nitrogen (SN ₂₎ is a refrigerant in the refrigerant forward path 20 In the refrigerant return path 21, liquid liquid nitrogen (LN ₂ ) melted in the forward path flows.

As described above, in this embodiment, all of the solid latent heat of melting in slush nitrogen is consumed in the refrigerant forward path 20, and liquid nitrogen is mainly present in the refrigerant return path 21. In this case, the heat generated in the cable is cooled only by the slush nitrogen from the refrigerant forward path 20. Even if the liquid nitrogen in the refrigerant return path 21 is heated and the temperature rises, the heat is finally absorbed by the lowest slush nitrogen. Of course, the same effects as in Reference Example 1 described above, that is, the melting latent heat of the solid, which is lower in temperature than liquid nitrogen, can be used. Compared with the case of using only liquid nitrogen, it has an effect that it can be cooled in a small amount.

Next, another example of the superconducting power transmission cable of FIG. 2 will be described with reference to FIGS.
The superconducting power transmission cable 10 shown in FIG. 3 has a configuration suitable for a case where the cooling section length is a long distance, and a superconductor 12 and an insulating layer (not shown) are wound around the former 11, and the outer peripheral side thereof is wound. An external heat insulating tube 15 is provided through a heat insulating vacuum layer 17. A refrigerant forward path 20 is formed inside the former 11.
The heat insulating vacuum layer 17 is provided with a radiation shield 16, and the radiation shield 16 envelops the superconductor 12 leaving at least a part of the heat insulating vacuum layer 17. The radiation shield 16 is provided for the purpose of blocking radiant heat from the outside, and the material thereof is preferably excellent in heat conduction and low in emissivity. For example, polished stainless steel or copper is used. Further, on the outside of the radiation shield 16, be generally provided radiation shield layer of a plurality by Su - Per insulation termed aluminum deposited plastic thin film (for example, about 20 sheets) (not shown) preferable.
Further, on the radiation shield 16, a refrigerant return path 21 is disposed in parallel with the superconductor 12. Slush nitrogen flows in the refrigerant forward path 20, and liquid nitrogen mainly flows in the refrigerant return path 21.
In this case, the superconductor 12 is cooled by heat conduction from slush nitrogen flowing through the refrigerant forward path 20 inside. The outside is covered with a radiation shield of about 63 to 77 K that has passed through the vacuum heat insulating layer 17. For this reason, there is no heat penetration from the outside, and cooling can be performed efficiently.

The superconducting power transmission cable 10 of FIG. 4 is also suitable for a long-distance cooling section length, in which a superconductor 12 and an insulating layer (not shown) are wound around a former 11 and a heat insulating vacuum layer 17 is provided on the outer peripheral side thereof. An external heat insulating tube 15 is provided. A refrigerant forward path 20 is formed inside the former 11. Further, a refrigerant return path 21 is provided on the outer peripheral side of the superconductor 12, and the vacuum heat insulation pipe 17 is provided between the superconductor 12 and the refrigerant return path 21 and between the refrigerant return path 21 and the external heat insulation pipe 15. The configuration is arranged. Then, slush nitrogen flows in the refrigerant forward path 20 and liquid nitrogen mainly flows in the refrigerant return path 21.
Thus, by using the refrigerant return path 21 as a radiation shield, even if all the solid slush nitrogen is melted in the refrigerant forward path 20, the temperature of the liquid nitrogen reaching the cable start end via the refrigerant return path 21 is increased. If it is 77K or less, bubbles are not generated in the piping, and the refrigerant can be efficiently flowed without causing pressure loss.
3 and FIG. 4, in addition to being applied to the first embodiment, as in the above-described reference example 1, a configuration in which slush nitrogen is allowed to flow in both the refrigerant forward path 20 and the refrigerant return path 21 can also be employed. .

FIG. 5 shows a schematic configuration diagram of a slush nitrogen generator according to Embodiment 2 of the present invention.
The slush nitrogen generator of the present embodiment is a refrigerant generating means provided in a cooling facility installed at the end of the superconducting power transmission cable 10 described in Reference Example 1 or Example 1 . The cooling facility includes a pressure feed pump and a slush nitrogen generator, and slush nitrogen generated by the generator is supplied into the superconducting power transmission cable by the pressure pump.
In the slush nitrogen generator, the cryogenic vessel 30 is filled with liquid nitrogen, and the ejector 31 disposed in the cryogenic vessel 30 is supplied with a low temperature such as liquid helium or cold helium gas from the working fluid supply line. A working fluid is supplied. As the refrigerant, neon, hydrogen, or the like can be used in addition to helium.
The space 36 above the liquid nitrogen in the cryogenic vessel 30 has an exhaust line 33 having a vacuum pump 32 and a valve, and an exhaust line 34 having a valve for keeping the space 36 at a pressure slightly higher than the atmospheric pressure. Is open.

The lower part of the liquid nitrogen suction pipe 35 connected to the suction port of the ejector 31 is immersed in the liquid nitrogen.
When the low-temperature container 30 is sealed and the inside of the container is depressurized by the vacuum pump 32, the liquid nitrogen evaporates, and the temperature of the liquid nitrogen decreases due to latent heat of vaporization. A low temperature working fluid is supplied when the temperature of liquid nitrogen reaches around 65K, which is slightly higher than the melting point at atmospheric pressure, that is, the temperature at which it solidifies, and the inside of the container is maintained at atmospheric pressure or slightly higher pressure.
When a low-temperature working fluid is supplied to the ejector 31, liquid nitrogen is sucked into the ejector 31 through the suction pipe 35 by the working fluid jet ejected from the ejector nozzle, and the liquid nitrogen passes through the diffuser of the ejector 31 together with the refrigerant. 36 is ejected. Liquid nitrogen is vigorously mixed with the refrigerant in the diffuser and cooled to become solid nitrogen having a fine and relatively uniform particle diameter. The pressure increased by the working fluid is adjusted by exhausting through the exhaust line 34.

In order to prevent the liquid nitrogen liquid surface from being frozen by the low-temperature working fluid, it is preferable to provide a stirring blade near the liquid surface and perform stirring and mixing.
Further, the mixed solid is uniformly mixed with a stirring blade 37 so as to prevent the generated solid nitrogen from falling and concentrating on the bottom of the liquid nitrogen, and slashed.
Slush nitrogen accumulates in the lower part of the container 30, and slush nitrogen is discharged through a discharge line 38 equipped with a valve at an appropriate time, and introduced into the refrigerant forward path of the superconducting power transmission cable 10 by the pressure pump 39.
By using a slush nitrogen generator as described above, the particle size of solid nitrogen in slush nitrogen can be made relatively uniform and small, and pressure loss is reduced even when flowing through the refrigerant path of a superconducting power transmission cable. be able to. Further, by applying the slush nitrogen generator of this embodiment, the particle size of solid nitrogen in the slush nitrogen can be easily controlled, and the slush nitrogen can be optimized.

FIG. 6 shows a schematic configuration diagram of a slush nitrogen generating apparatus according to Example 3 of the present invention.
Slush nitrogen generator of the present embodiment 3, as in Example 2 described above, is provided in Reference Example 1 or Example 1 was superconducting power transmission cable 10 within the cooling equipment installed in an end portion of the described. The cooling facility has a pressure pump and a slush nitrogen generator, and slush nitrogen generated by the generator is supplied into the superconducting power transmission cable by the pressure pump.
The slush nitrogen generator is configured to depressurize the gas phase part in the heat insulating container 40 storing liquid nitrogen with a vacuum pump 41, the liquid nitrogen evaporates as the depressurization proceeds, and the temperature of the liquid nitrogen decreases due to latent heat, Solid nitrogen begins to form when the contents reach the triple point of nitrogen. Reaching the triple point is confirmed by the thermometer 42 that the temperature does not drop below 63.1K. When the triple point is reached, the vacuum pump 41 is stopped and the level is measured by the level gauge 43. Thereafter, the vacuum pump 41 is operated, and both stirring blades 44 and 45 are also rotated.

Due to the reduced pressure, solid nitrogen is formed thinly on the entire surface of liquid nitrogen. If left as it is, the solid nitrogen is sucked up above the suction port of the vacuum pump 41 and separated from the liquid, and the next solid nitrogen is generated in the space. The generated solid nitrogen becomes solid nitrogen 46 refined by the stirring blades 44 and 45, and is mixed with the liquid to become slush nitrogen. The generated slush nitrogen is introduced into the refrigerant forward path of the superconducting power transmission cable 10 by the pressure feed pump 47.
As described above, the slush nitrogen generating apparatus of the third embodiment can generate solid nitrogen without using other refrigerants, so that it does not require a large facility such as a compression apparatus when using other refrigerants. Slush nitrogen can be generated with a simple structure and a compact device.

FIG. 7 shows a schematic configuration diagram of a slush nitrogen generator according to Embodiment 4 of the present invention.
Slush nitrogen generator of the present embodiment 4, as in Example 2 described above, is provided in Reference Example 1 or Example 1 was superconducting power transmission cable 10 within the cooling equipment installed in an end portion of the described. As shown in the drawing, the slush nitrogen generator includes a liquid nitrogen tank 50, a container 53 having a nozzle 52, a vacuum pump 54, and a stirring blade 55.
A liquid nitrogen supply pipe is connected to the liquid nitrogen tank 50 in which liquid nitrogen is stored, and one is connected to the container 53, and one is connected to the nozzle 52 disposed above the container 53 via the pump 51. ing. A vacuum pipe is connected from the ceiling of the container 53, and the inside of the container can be decompressed by a vacuum pump 54.
Furthermore, a stirring blade 55 is provided at the bottom of the container so that the contents can be stirred. In addition, a content take-out pipe is provided near the bottom of the side wall of the container 53, and the content is guided to the refrigerant forward path of the superconducting power transmission cable 10 by a pressure feed pump 58.

The operation of the slush nitrogen generator will be described. First, liquid nitrogen stored in the liquid nitrogen tank 50 is jetted from the nozzle 52 into the container 53 maintained under reduced pressure by the vacuum pump 54. Nitrogen droplets 56 having a uniform fine particle diameter are formed and dispersed by the nozzle 52. While the droplet particles 56 stay in the space of the container 53, the nitrogen on the surface of the droplet particles evaporates, and the latent heat of vaporization causes The droplet particles solidify to produce solid nitrogen 57. The solidified solid nitrogen 57 falls and is mixed and stirred with liquid nitrogen by the stirring blade 55 to generate slurried slush nitrogen. The generated slush nitrogen is introduced into the refrigerant forward path of the superconducting power transmission cable 10 by the pressure feed pump 58. The particle size of the droplet nitrogen is determined by the flow rate caused by the nozzle diameter and the jet pressure. Therefore, the particle diameter of solid nitrogen in slush nitrogen is adjusted by the nozzle diameter and the ejection pressure.
Thus, by using the slush nitrogen production apparatus according to the present embodiment, slush nitrogen can be easily generated with a simple apparatus.

It is a block diagram of the superconducting power transmission cable which concerns on the reference example 1, (a) is a sectional side view, (b) is sectional drawing. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the superconducting power transmission cable which concerns on Example 1 of this invention, (a) is sectional side view, (b) is sectional drawing. It is sectional drawing of the superconducting power transmission cable which shows another example of FIG. It is sectional drawing of the superconducting power transmission cable which shows another example of FIG. 2, FIG. It is a schematic block diagram of the slush nitrogen production | generation apparatus which concerns on Example 2 of this invention. It is a schematic block diagram of the slush nitrogen production | generation apparatus which concerns on Example 3 of this invention. It is a schematic block diagram of the slush nitrogen production | generation apparatus which concerns on Example 4 of this invention. The schematic diagram of the conventional power transmission cable using a high temperature superconductor is shown. The schematic block diagram of the conventional power transmission cable system is shown.

DESCRIPTION OF SYMBOLS 10 Superconducting power transmission cable 11 Former 12 Superconductor 13 Insulating layer 14 Inner heat insulation pipe 15 Outer heat insulation pipe 16 Radiation shield 17 Heat insulation vacuum pipe 20 Refrigerant forward path 21 Refrigerant return path 30 Low temperature container 31 Ejector 39 Pressure feed pump 40 Thermal insulation container 52 Injection nozzle 53 Container 58 Pressure feed pump

Claims (7)

A high-temperature superconductor wound around the outer periphery of the former, two or more refrigerant paths including a refrigerant forward path and a refrigerant return path through which a refrigerant that cools the superconductor is passed, and a heat insulating tube that encloses the superconductor and the refrigerant path In a superconducting power transmission cable with
The refrigerant forward path is formed inside the former,
A tubular heat radiation shield is provided on the outer periphery of the superconductor via a heat insulating vacuum layer,
The refrigerant return path is provided through the heat insulating vacuum layer in parallel along the superconductor,
At least the refrigerant flowing in the refrigerant forward path is slush nitrogen containing fine solid nitrogen in liquid nitrogen ,
A superconducting power transmission cable, wherein the refrigerant flowing through the refrigerant return path is slush nitrogen or liquid nitrogen in which fine solid nitrogen is contained in liquid nitrogen . A high-temperature superconductor wound around the outer periphery of the former, two or more refrigerant paths including a refrigerant forward path and a refrigerant return path through which a refrigerant that cools the superconductor is passed, and a heat insulating tube that encloses the superconductor and the refrigerant path In a superconducting power transmission cable with
The refrigerant forward path is formed inside the former,
The tubular refrigerant return path is provided on the outer periphery of the superconductor via a heat insulating vacuum layer,
At least the refrigerant flowing in the refrigerant forward path is slush nitrogen containing fine solid nitrogen in liquid nitrogen ,
A superconducting power transmission cable, wherein the refrigerant flowing through the refrigerant return path is slush nitrogen or liquid nitrogen in which fine solid nitrogen is contained in liquid nitrogen .   The superconducting power transmission cable according to claim 1 or 2, wherein the refrigerant flowing in the refrigerant forward path is slush nitrogen, and the refrigerant flowing in the refrigerant return path is mainly liquid nitrogen.   The superconducting power transmission cable according to claim 1 or 2, wherein any one of the two refrigerant paths is slush nitrogen. A superconducting power transmission cable comprising the superconducting power transmission cable according to any one of claims 1 to 4, a cooling facility comprising means for generating the refrigerant, and means for pumping the refrigerant to the superconducting power transmission cable. In the system,
The refrigerant generating means has a low-temperature container filled with liquid nitrogen, and an ejector that injects a low-temperature working fluid having a pressure higher than the space in the container into the container to suck out the liquid nitrogen;
In the refrigerant generating means, the liquid nitrogen sucked and ejected by the low temperature working fluid is cooled by the low temperature working fluid and falls as fine solid nitrogen, and is mixed with the liquid nitrogen to generate slush nitrogen. The superconducting power transmission cable system is characterized in that the slush nitrogen is introduced into the refrigerant path by the pumping means. A superconducting power transmission cable comprising the superconducting power transmission cable according to any one of claims 1 to 4, a cooling facility comprising means for generating the refrigerant, and means for pumping the refrigerant to the superconducting power transmission cable. In the system,
The refrigerant generating means has a heat insulating container filled with liquid nitrogen, a pressure reducing means for reducing the pressure inside the heat insulating container, and a stirring means for stirring the inside of the heat insulating container,
In the refrigerant generating means, the liquid nitrogen in the heat insulating container is depressurized by the pressure reducing means to lower the temperature, reach the triple point to generate solid nitrogen, and the solid nitrogen atomized by stirring by the stirring means A superconducting power transmission cable system configured to generate slush nitrogen by mixing with liquid nitrogen and introduce the slush nitrogen into the refrigerant path by the pumping means. A superconducting power transmission cable comprising the superconducting power transmission cable according to any one of claims 1 to 4, a cooling facility comprising means for generating the refrigerant, and means for pumping the refrigerant to the superconducting power transmission cable. In the system,
The refrigerant generating means has a container kept under reduced pressure, a nozzle for injecting liquid nitrogen into the container, and a stirrer for stirring the inside of the container;
In the refrigerant generation means, liquid nitrogen droplet particles ejected from the nozzle are evaporated in a reduced-pressure atmosphere, and the droplet particles are solidified by latent heat of vaporization to form solid nitrogen, mixed with the liquid nitrogen and slush nitrogen And a slush nitrogen is introduced into the refrigerant path by the pumping means.

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