JP2000096041A - Method and apparatus for transporting hydrate slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transport an equivalent quantity of heat to the case where water is employed as medium through the medium of a smaller motive power or a pipe having a smaller diameter than that in transporting cold through the medium of water by transporting a specific hydrate slurry while maintaining a specific solidus rate. SOLUTION: The method of this invention is to transport a hydrate slurry including particles prepared by cooling an aqueous solution of a guest compound capable of forming hydrate at >=0 deg.C while maintaining <=38% solidus rate through the medium of a piping system pref. in a state maintained so as for heat transportation motive power to become smaller than that in transporting heat through the medium of water in correspondence to an arbitrary flow speed of hydrate slurry in a piping system. The guest compound is pref. at least one selected from tetra(n-butyl)ammonium, tetra(i-butyl)ammonium and tri(i-amyl) sulfonium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for efficiently transferring cold energy by means of a hydrate slurry. More specifically, the present invention relates to the transportation of a hydrate slurry capable of transporting the same amount of cold energy as when using water as a medium, by using smaller power or a small-diameter pipe when transporting cold energy using water as a medium. Method and apparatus.

[0002]

2. Description of the Related Art Hitherto, a heat storage device has been developed in which an aqueous solution containing a guest compound is cooled to generate a hydrate at a temperature of 0 ° C. or higher, and a large amount of cold heat is stored by the latent heat. Such a heat storage device can store, by the latent heat of the hydrate, cold energy of several times the amount of heat in the case of heat storage by cold water, and can generate a hydrate at a temperature of 0 ° C. or more. Therefore, there is an advantage that a hydrate can be produced by, for example, an absorption refrigerator using waste heat.

[0003] Further, by controlling the conditions when the above aqueous solution is cooled to form a hydrate, for example, the dissolved amount of carbon dioxide in the aqueous solution, the adhesion to the inner wall of the pipe and the aggregation of particles are prevented. Techniques have also been developed to produce stable and fine particulate hydrates and produce hydrate slurries with high fluidity and stability. In addition, a technology has been developed that utilizes such characteristics of the hydrate slurry and directly supplies the hydrate slurry as a refrigerant to equipment on the load side, thereby simplifying the equipment and increasing the efficiency. I have. Such a technique is disclosed in Japanese Patent Application Nos. 10-163518 and 10-1635 by the same applicant as the present application.
No. 19 and the like.

By the way, the hydrate slurry generated as described above is sent to a heat storage tank or a load side device, for example, an indoor unit of an air conditioner, through a piping system by a pump or the like. For this reason, this hydrate slurry is transported through a long and complicated piping system. In particular, in a heat storage device that manufactures and stores this hydrate slurry using midnight power or waste heat, and uses this cold heat for air-conditioning of a building or the like, the hydrate slurry has a complicated structure inside the building. Therefore, it is necessary to circulate through long pipes, and it is necessary to pay attention to the transportation efficiency.

[0005] In the future, a regional cooling and heat supply center for producing and storing a large amount of hydrate slurry by utilizing waste heat from midnight power, waste incineration facilities and factories, etc., will be constructed. It is also planned to send the hydrate slurry to factories and homes and use it as a cold heat source. In such a case, it is necessary to transport the hydrate slurry through a longer and more complicated piping system, and it is necessary to pay more attention to its transport efficiency.

[0006] In examining the transport efficiency of the hydrate slurry as described above, the first issues to be considered are that existing piping and other equipment can be diverted and that the hydrate slurry is transported. To reduce the cost of equipment required for transportation and the power required for transportation.

That is, when installing a heat storage device as described above in an air-conditioning system of an existing building or the like, replacing the piping or the like of the air-conditioning system in the building would greatly increase the cost required for the construction and would not be practical. Absent. For this reason, it is necessary to transport the hydrate slurry using the existing refrigerant pipe or the like as it is. Also, even when installing air conditioning equipment for a new building, the equipment such as pipes and valves must be of conventional standards, so even in this case, consider the use of existing materials. There is a need. Even when constructing the above-mentioned regional air-conditioning system, it is the same as above and the scale is large, so that more careful consideration is necessary.

[0008] Conventionally, the transportation of cold heat of air conditioning equipment has been performed by sensible heat of cold water or brine. Hydrate slurries can retain a large amount of cold heat due to latent heat, but because of their high flow resistance, the power of the pump required to transport the inside of the pipes may increase. An increase in power may reduce the energy saving effect.

[0009]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and when transporting cold heat by using a hydrate slurry, is equal to or less than the case of transporting cold heat by conventional cold water. The same cold energy can be transported by power and smaller-diameter pipes, and existing pipes, existing materials and equipment can be diverted, and energy consumption can be saved without increasing the power required for transport. It is an object of the present invention to provide a method and an apparatus for transporting a hydrate slurry which do not reduce the effect.

[0010]

The method of the present invention according to claim 1, wherein the hydrate particles formed by cooling an aqueous solution of a guest compound which forms a hydrate at a temperature higher than 0 ° C. A method of transporting a hydrate slurry containing: wherein the hydrate slurry is transported via a piping system while maintaining its solid phase ratio within a range of 38% or less. .

As described above, this hydrate slurry has a higher flow resistance than water or brine, but this hydrate slurry has the properties of a non-Newtonian fluid and, as described above, a large amount of cold heat due to latent heat. And the amount of heat that can be held depends on the amount of hydrate, that is, the solid phase ratio of the hydrate slurry.

Therefore, utilizing the above characteristics,
By transporting this hydrate while maintaining the range of the specific solid fraction, when the calorific value of the transported cold is the same,
Power required for transportation can be reduced as compared with the case of cold water, or the diameter of piping required for transportation can be made smaller. Therefore, it is possible to divert the existing piping equipment or existing piping and other materials as they are, reduce the power required for transportation, and prevent the effect of energy saving from lowering.

[0013] The method of the present invention according to claim 2 comprises:
The hydrate slurry transported in the piping system has a solid power in which the power required for transport for the transport calorie is smaller than the power required for transporting heat by water, corresponding to the arbitrary flow rate. It is characterized in that it is transported through a piping system while maintaining the phase ratio in the range.

Even within the range of the solid phase ratio of the hydrate slurry, the power required for transporting the hydrate slurry changes according to the flow rate of the hydrate slurry. Therefore, as described above, the hydrate slurry can be transported in an optimal range by adjusting the solid phase ratio of the hydrate slurry according to the flow rate.

[0015] The method of the present invention according to claim 3 is characterized in that:
The guest compound includes a tetra-n-butylammonium salt, a tetra-iso-amylammonium salt,
It contains at least one compound of an o-butylphosphonium salt and a triiso-amylsulfonium salt. These guest compounds have a melting temperature of the hydrate in the range of 4 ° C. to 25 ° C., and the characteristics of the produced hydrate particles are stable. It has optimal characteristics.

The device according to the present invention described in claim 4 is:
A refrigeration apparatus for cooling an aqueous solution of a guest compound that forms a hydrate at a temperature higher than 0 ° C. to produce a hydrate slurry containing hydrate particles, and a heat storage for storing the produced hydrate slurry A hydrate having a tank and a piping system communicating with the refrigeration apparatus, the heat storage tank, and the cold load device, and having at least a solid fraction of 38% or less in the piping system communicating with the load device. It is characterized in that the slurry is circulated.

Therefore, even when this piping system is long and complicated, the existing piping system can be used as it is, and even when newly constructed, the piping diameter can be made smaller and the power required for transportation can be reduced. Does not increase.
Therefore, the manufacturing and operating costs of this device can be reduced.

The present invention according to claim 5 further comprises a solid phase fraction detector for detecting a solid phase fraction of the hydrate slurry circulated in the piping system. According to the present invention, the solid phase ratio of the hydrate slurry is adjusted in accordance with the flow rate of the hydrate slurry to be transported so that the power required for the transport with respect to the heat of transport is minimized.

As described above, the power required for transportation with respect to the amount of heat transported by the hydrate slurry varies depending on the flow rate of the hydrate slurry, and the power required for transportation for an arbitrary flow rate. There is a minimum solid fraction value. Therefore, the solid phase fraction detector detects the solid phase fraction of the hydrate slurry to be circulated, and adjusts this solid phase fraction according to the flow rate to minimize the power required for transportation. Energy required for transportation can be saved.

The device according to the present invention described in claim 6 is:
A district cooling and heat supply facility including the refrigeration apparatus and the heat storage tank is configured, and the hydrate slurry is transported from the district cooling and heat supply facility to a cooling load side device in a predetermined area via a piping system. It is assumed that. Therefore, it is possible to construct a regional air-conditioning system with low equipment costs and low operation costs.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the drawings, together with an apparatus utilizing the method. FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a heat storage type air conditioning system for a building such as a building utilizing the method of the present invention. . The structure shown in FIG. 1 can be adopted both when modifying an existing air conditioner or when constructing a new one.

In the drawing, reference numeral 1 denotes a refrigerating apparatus, which may be a compression type refrigerating machine using midnight power or an absorption refrigerating machine using waste heat or the like. Reference numeral 2 denotes a cooling tower, in which a refrigerant is circulated by a pump 3 and discharges heat from the refrigeration apparatus 1.

The low-temperature refrigerant generated by the refrigerating apparatus 1 is circulated between the heat exchanger 4 and a pump 5 by a pump 5. An aqueous solution of a guest compound is circulated through the heat exchanger 4.
Cooling is performed by heat exchange with the above-mentioned refrigerant, hydrate particles are formed, and a hydrate slurry is generated. Then, the hydrate slurry is sent to the heat storage tank 6 and stored.

In the case of this embodiment, the above-mentioned guest compound is a tetra-n-butylammonium bromide salt (hereinafter referred to as TBA).
B) is used. In addition, as this guest compound, at least one compound of a tetra n-butylammonium salt, a tetraiso-amylammonium salt, a tetraiso-butylphosphonium salt, and a triiso-amylsulfonium salt may be used. What is included is used.

In the figure, reference numeral 20 denotes a building in which an air conditioner is installed, in which a plurality of heat load side devices, for example, an indoor air conditioner unit 21 are installed. The above devices and the indoor air conditioning units 21 are connected by a series of piping systems 10.

That is, reference numeral 11 denotes a hydrate slurry feed pipe, through which the hydrate slurry generated in the heat exchanger 4 is sent to the heat storage tank 6. The hydrate slurry stored in the heat storage tank 6 is sent to a pump 16 via a switching valve 14, and is sent to each indoor air conditioning unit 21 by the pump 16. The switching valve 14 communicates with the hydrate slurry feed pipe 11 and, in addition to the hydrate slurry stored in the heat storage tank 6, transfers the hydrate slurry generated in the heat exchanger 4. It can be supplied directly to the pump 16.

The hydrate slurry sent by the pump 16 is circulated through the outgoing pipe 12 and the return pipe 13, heat exchanged in each indoor air conditioning unit 21, and returned to the heat exchanger 4. It is. Reference numerals 17 and 18 denote on-off valves.

The solid fraction SPF of the hydrate slurry circulating in the piping system 10, that is, the ratio of the hydrate particles contained to the solution, is detected and monitored by the solid fraction detector 15. It is adjusted to a solid phase ratio as described below. The solid-phase fraction detector 15 irradiates the hydrate slurry with ultrasonic waves, laser light, or the like, and can measure the solid-phase fraction online from the reflected waves.

The solid fraction detected by the solid fraction detector 15 is sent to, for example, the control device 19 and processed, and the solid fraction is made to correspond to the flow rate of the hydrate slurry. Adjustment so as to be in an optimum range as described later. The solid phase ratio is adjusted by, for example, controlling the operating conditions of the heat exchanger 4 and the refrigerating device 1 by the control device, and controlling the solid phase ratio of the hydrate slurry to be generated to a desired range. In this embodiment, an example in which the adjustment of the solid fraction is performed automatically is described, but in some cases, in accordance with the value of the solid fraction detected by the solid fraction detector 15, The operator may operate the operating conditions of the heat exchanger 4 and the refrigeration apparatus 1 described above.

Next, a description will be given of a method of controlling the transport characteristics and the like of the hydrate flowing through the piping system 10 by controlling the operation of the above-mentioned apparatus and the solid phase ratio of the hydrate flowing through the piping system 10. FIG. 2 shows hydrate formation characteristics related to the concentration and temperature of an aqueous solution of the above-mentioned guest compound TBAB. In the range of the concentration and the temperature in the region B in FIG. 2, no hydrate is generated, and only the aqueous solution exists. In the region A, hydrate is generated,
The hydrate and the aqueous solution coexist. Note that this hydrate is formed as stable particles as described above, and is a hydrate slurry in which these are mixed.

In this region A, the ratio between the amount of hydrate particles formed and the amount of aqueous solution, that is, the solid phase ratio SPF, is determined by the concentration and temperature of the aqueous solution, and the concentration is high and the cooling temperature is high. The lower the value, the higher the solid fraction, and conversely, the lower the concentration, and the higher the temperature, the lower the solid fraction. Therefore, in the apparatus of this embodiment, a hydrate slurry having a desired solid fraction can be generated by appropriately setting the concentration of the aqueous solution and the cooling temperature in the heat exchanger 4.

As described above, by controlling the conditions for producing the hydrate slurry, the hydrate particles can adhere to the wall of the container or the like, or the hydrate particles can aggregate with each other. Without this, a stable hydrate slurry with high fluidity can be obtained. The hydrate slurry stored in the heat storage tank 6 maintains the solid phase ratio of the hydrate slurry generated in the heat exchanger 4.

FIG. 3 shows the distribution characteristics of the diameter of the produced hydrate particles. FIG. 3 shows the result of the experiment by the present inventors, in which the distribution of the diameter of the produced hydrate particles is shown as a volume ratio with respect to the whole particles. As apparent from FIG. 3, for example, the solid phase ratio SPF is 1
In the range of 5% to 47%, the particle size distribution is close to the normal distribution, and even if the SPF value is different, the characteristics of this distribution do not change much. Note that this S
When the value of PF is small, for example, 4%, the distribution of particle diameters deviates from the normal distribution.

The characteristics close to the normal distribution as described above give the hydrate slurry high fluidity, and even if the solid fraction changes, its fluidity characteristics do not change much, and the hydrate slurry can be stably transported. Can be handled. Therefore, it is preferable to maintain the solid phase ratio of the hydrate slurry to be formed in the range of about 15% to 47%.

Next, FIG. 4 shows the relationship between the hydrate slurry as described above, which is transported through a pipe of a certain diameter, the power such as pump power required for the transport, and the chilled water to be transported. The result of the experiment compared with the case where cold heat was transported as a medium is shown. In FIG. 4, the data is arranged for easy understanding, and when the calorific value of the cold energy to be transported is equal to the power required for transport for both, when the hydrate slurry is distributed, It is shown as a ratio between the required pipe diameter Ds and the required pipe diameter Dw when cold water is circulated. Therefore, when the value of Ds / Dw is 1.0, it indicates that both require the same diameter pipe.

In FIG. 4, as shown in FIG.
Some solid phase ratio SPFs within the range of the solid phase ratio suitable for transportation in the piping system are shown in relation to the flow rate of the hydrate slurry (water) in the piping. In this FIG.
In the case of a hydrate slurry having a solid phase ratio SPF in the range of 20% to 35%, the higher the flow rate, the higher the Ds / Dw
Is small, that is, the required pipe diameter is reduced. Such properties are believed to be due to the property that the hydrate slurry is a non-Newtonian fluid, with the viscosity decreasing as the flow shear rate increases.

In particular, when the flow rate is 2.0 m / s or more, Ds / Dw
Is 1.0 or less, that is, it is sufficient to transport the cold heat by the hydrate slurry with a pipe having a smaller diameter. Therefore, by setting the flow velocity to 2.0 m / s or more, it is possible to transport cold heat of the same amount of heat with the same power using existing pipes that transport cold heat with cold water. It also shows that when a new piping system is constructed, it is possible to use smaller-diameter piping, for example, Ds / D
If the hydrate slurry is allowed to flow at a flow rate in the range where the value of w is 0.5, a pipe having a diameter 1/2 that of cold water can be used, and the cost of equipment can be greatly reduced.

FIG. 5 shows the results of the same experiment as described above in relation to the solid phase ratio SPF. FIG. 5 shows that in the case of a hydrate slurry in which the solid fraction SPF is in the range of 17% to 34%, the value of Ds / Dw is 1.0 or less, and whether the existing piping system can be used. Alternatively, it is shown that in the case of a new installation, a pipe having a smaller diameter than the conventional one can be adopted. Further, it is shown that the value of Ds / Dw changes with the solid phase ratio SPF even at the same flow rate.

It should be noted in FIG. 5 that there is a condition that minimizes the value of Ds / Dw in any solid phase ratio SPF. In other words, if the hydrate slurry is transported in this range, the pipe with the smallest diameter can be used, and the power required for transportation can be minimized.

FIG. 6 shows the value Ps / Pw of the power Ps required for transporting the same amount of cold heat by the hydrate slurry and the power Pw required for transport by the cold water.
This is shown in relation to the flow rate and the solid fraction SPF.

The curve a in FIG. 6 shows the upper limit of the solid fraction SPF for an arbitrary flow rate when Ps / Pw = 1 from the characteristics shown in FIG. A curve b shows the lower limit of the solid fraction SPF for an arbitrary flow rate when Ps / Pw = 1. Therefore, corresponding to the flow rate, the solid fraction S
By maintaining the PF in the region between the curves a and b, the power required for transportation can be reduced as compared with the case where cold heat is transported by cold water.

In an actual piping system, the flow velocity of the fluid in the piping is designed to be about 3 m / s or less. Therefore, for an actual piping system, to make Ps / Pw 1 or less, What is necessary is just to maintain the solid phase ratio SPF at 38% or less.

As shown in the above description of FIG. 5,
There is a condition that minimizes the required power or the required pipe diameter when transporting the same amount of heat, but the curve c in FIG.
Shows the relationship between the required power ratio, the flow rate at which Ps / Pw is minimized, and the solid fraction SPF. As is apparent from FIG. 6, the solid phase ratio SPF is 20
It is shown that when the amount is in the range of 30% to 30%, it can be transported with minimum power.

Considering the amount of cold heat transport of the hydrate slurry described above and the power required for transporting the slurry, the pipe diameter, and the properties such as the solid fraction and the flow rate, hydration slurry can be used as a general condition. When the solid phase ratio of the product slurry exceeds 38%,
It is difficult to transport the hydrate slurry with the same transport power and pipe diameter as in the case of cold water. Therefore, in order to lower the cost and operating cost of the piping equipment in the case of using an existing piping system or newly constructing it, compared to the case of conventional cold water transport using cold water, the solid phase ratio S
The PF needs to be 38% or less.

In addition, there is a condition under which the power required for transporting the hydrate slurry and the pipe diameter are minimized with respect to the amount of heat to be transported. Therefore, the hydrate slurry is transported so as to satisfy these conditions. This would minimize the required power and piping equipment costs.

The present invention is not limited to the first embodiment. For example, it is possible to construct a district heating and cooling system as shown in FIG. 7 using the transportation method of the present invention.

This embodiment is provided with district cooling and heat supply centers 30a and 30b which cover a predetermined range of the area. And this district cooling and heat supply center,
Each is provided with a refrigerating device 31, such as an absorption refrigerating device, a hydrate slurry producing device 32, and a hydrate slurry storing device 33.

Then, for example, waste heat discharged from the refuse incineration facility 40, the factory 41, etc., for example, low-temperature steam, etc., is sent to each of the regional refrigeration centers 30a, 30b via the piping system 42, and the refrigeration unit 31 converts the refrigeration The hydrate slurry is produced in the hydrate slurry production device 32 by this cold heat and stored in the hydrate slurry storage device 33.

Further, the hydrate slurry is supplied to the cooling loads of the factories 43, the buildings 44, 45, 46 such as buildings, the private houses 47, 48 and the like via the piping systems 35a, 35b in the area, and Source. The flow rate and solid phase ratio of the hydrate slurry to be supplied to each cooling load may be measured by the measuring device 36, and a fee may be collected in accordance with the supplied cooling amount.

In the district heating / cooling system as described above, the piping systems 35a and 35b for transporting the hydrate slurry are long, and therefore, by transporting the hydrate slurry by the above-described method, it is necessary to transport the hydrate slurry. Power can be greatly reduced, and a higher energy saving effect can be obtained. Further, as described above, since the diameter of the pipe can be made smaller than in the past, the construction cost can be significantly reduced.

The present invention is not limited to the above embodiment, and is not limited to the transport of the hydrate slurry in the air conditioning equipment, but can be applied to the transport of the hydrate slurry for other cold / hot transport. Of course.

[0052]

As described above, the method of the present invention has a solid content of 38%.
% Of the hydrate slurry, the power required for transportation is lower than that of chilled water, or the piping required for transportation when the amount of chilled heat to be transported is the same. Can be made smaller.
Therefore, it is possible to divert existing piping equipment or existing piping and other materials as they are, and to reduce the power required for transportation and prevent the effect of energy saving from being reduced. The effect is great.

In the apparatus of the present invention, the hydrate slurry having a solid fraction of 38% or less flows through at least the piping system communicating with the load-side equipment. Therefore, even when the piping system is long and complicated, Existing piping system can be used as it is,
Even in the case of new construction, the pipe diameter can be made smaller, the power required for transportation can be reduced, and the cost of manufacturing and operating this device can be reduced. is there.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the concentration and temperature of an aqueous solution and hydrate formation.

FIG. 3 is a diagram showing a particle size distribution of hydrate particles produced.

FIG. 4 is a diagram showing a relationship between a flow rate of a hydrate slurry and a pipe diameter.

FIG. 5 is a diagram showing a relationship between a solid phase ratio of a hydrate slurry and a pipe diameter.

FIG. 6 is a diagram showing the relationship between the flow rate of a hydrate slurry and the solid fraction.

FIG. 7 is a schematic system diagram of a district cooling and heating system according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 4 Heat exchanger 6 Heat storage tank 10 Piping system 16 Pump 21 Indoor air-conditioning unit 30a, 30b District cooling and heat supply center 31 Refrigeration apparatus 33 Hydrate slurry storage apparatus 35a, 35b Piping system

Claims (6)

[Claims] 1. A method for transporting a hydrate slurry containing hydrate particles formed by cooling an aqueous solution of a guest compound forming a hydrate at a temperature higher than 0 ° C. A method for transporting a hydrate slurry, wherein the hydrate slurry is transported through a piping system while maintaining its solid phase ratio at 38% or less. 2. The hydrate slurry transported in the piping system has a motive power required for transportation corresponding to an arbitrary flow rate of the hydrate slurry in the case of transporting heat by water. The hydrate slurry transportation method according to claim 1, wherein the hydrate slurry is transported through a piping system while maintaining the solid phase ratio in a range smaller than the power. 3. The above-mentioned guest compound includes a tetra-n-butylammonium salt, a tetra-iso-amyl ammonium salt, a tetra-iso-butylphosphonium salt, and a tri-i-butylammonium salt.
2. The method for transporting a hydrate slurry according to claim 1, wherein the method comprises at least one compound of so-amylsulfonium salts. 4. A refrigeration apparatus for cooling an aqueous solution of a guest compound that forms a hydrate at a temperature higher than 0 ° C. to form a hydrate slurry containing hydrate particles, and a hydrate generated by the hydrate slurry A heat storage tank for storing the slurry, and a piping system communicating with the refrigeration apparatus, the heat storage tank and the cold load device, and at least a solid phase ratio of 38% in the piping system communicating with the load device. An apparatus for transporting hydrate slurry, which circulates the following hydrate slurry. 5. A solid phase fraction detector for detecting a solid phase fraction of the hydrate slurry flowing in the piping system, wherein a flow rate of the hydrate slurry transported in the piping system is controlled. 5. The hydrate slurry transport apparatus according to claim 4, wherein the solid phase ratio of the hydrate slurry is adjusted so that the power required for transport for the transport calorie is minimized. 6. A district cooling and heat supply facility including the refrigerating device and the heat storage tank, and transporting the hydrate slurry from the district cooling and heat supply facility to a cooling load side in a predetermined area via a piping system. 5. The hydrate slurry transport device according to claim 4, wherein: