JP2003171678A - Method and apparatus for loading of gas hydrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for loading of a gas hydrate in which a filling efficiency (storage efficiency) during storage and transportation is improved while a handling performance during loading is improved. <P>SOLUTION: The invention provides a method for loading of a pellet-shaped gas hydrate pellet b made of a gas hydrate. At the time of loading, the gas hydrate pellet b is mixed with a slurry mother liquor d to form a slurry. The slurry is conveyed to a solid-liquid separation apparatus 25 (45, 73), where the gas hydrate pellet b is separated from the slurry mother liquor d to be stored in a second storage tank 31 (48, 63). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas hydrate loading method and apparatus for loading pelletized gas hydrate pellets made of gas hydrate.

[0002]

2. Description of the Related Art Gas hydrate has a crystal structure in which one gas molecule is contained in a cage formed by water molecules. For example, for methane, the pressure is 3MP.
a, It is said that methane hydrate is produced by 8 molecules of methane and 46 molecules of water at a temperature of 0 ° C., and the volume thereof is reduced to 1/170 of that of methane gas in the standard state.

As described above, since gas hydrate has a high gas encapsulation property, natural gas hydrate can be used as a new transportation mode or storage mode of natural gas instead of LNG (liquefied natural gas). Attention has been paid.

Further, as a method of utilizing a gas hydrate having a high gas encapsulation property, a carbon dioxide ocean storage method can be considered. Regarding carbon dioxide, the temperature is 0 ° C. and the pressure is 1.
Since the hydrate is formed at a relatively low pressure of 2 MPa, it is expected that the greenhouse gas will be reduced by storing the carbon dioxide hydrate using the high-pressure environment in the deep sea.

By the way, as a method of transporting a gas hydrate using various transportation means such as a ship, a vehicle, or a container, a gas hydrate which is powder such as shaved ice or snow is pelletized or slurried. It has been proposed to transport it after converting it into a product.

However, when the gas hydrate pellets in which the gas hydrate is formed into pellets or the gas hydrate slurry in which the gas hydrate is formed into a slurry are handled, there are the following problems.

That is, the gas hydrate pellets are
Although there is an advantage that the filling efficiency at the time of storage, that is, the storage efficiency is high, on the other hand, the handling property at the time of cargo handling is not necessarily good. Further, when the gas hydrate pellets are handled, it is inevitable that the horizontal transportation and the vertical transportation are mixed, so that the transportation device becomes complicated and becomes large. Furthermore, since the gas hydrate pellets are transported in the gas phase, the cold insulation effect at the time of transportation is reduced.

On the other hand, when the gas hydrate slurry is loaded, it can be transported by using the pump and the pipe as in the case of the normal slurry transportation, so that it is easier to transport than the case where the gas hydrate pellets are loaded. Is.
Further, by preliminarily cooling the liquid refrigerant (mother liquor) having a large heat capacity, it is possible to suppress the temperature rise of the gas hydrate during transportation.

However, if the slurry is used as it is, the packing efficiency, that is, the storage efficiency is lower than that of the pellet, and the storage tank is inevitably increased in size.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is
Alternatively, the main object of the present invention is to provide a gas hydrate cargo handling method and apparatus that can improve the filling efficiency (storage efficiency) during transportation and the handling property during cargo handling.

[0011]

In order to solve such a problem, the present invention is constructed as follows.

(1) When loading gas hydrate pellets composed of gas hydrate, the gas hydrate pellets and the slurry mother liquor are mixed to form a slurry, and the slurry is transferred to a solid-liquid separation device. Then, the gas hydrate pellets are separated from the slurry mother liquor by the solid-liquid separator, and the second
A method of loading and unloading gas hydrate, characterized by storing in a storage tank.

(2) The gas hydrate according to (1), wherein the gas hydrate pellets and the slurry mother liquor are mixed in a pipe from the first storage tank storing the gas hydrate pellets to the solid-liquid separation device. How to handle rates.

(3) The gas hydrate pellets and the slurry mother liquor are mixed in a mixing tank arranged in a path from the first storage tank storing the gas hydrate pellets to the solid-liquid separator. (1) The method for loading and unloading gas hydrate according to the above item.

(4) The gas hydrate loading / unloading method according to (1), wherein the gas hydrate pellets and the slurry mother liquor are mixed in a first storage tank storing the gas hydrate pellets.

(5) When the first storage tank is emptied, the storage tank is preliminarily cooled by the slurry mother liquor in preparation for the storage of gas hydrate pellets. (2), (3) or (4) How to handle gas hydrate.

(6) The first storage tank is a land tank or a hold of a ship (2), (3), (4) or (5).
How to handle the described gas hydrate.

(7) The gas hydrate loading / unloading method according to (1), wherein the second storage tank is a hold of a ship or a tank on land.

(8) In a cargo handling apparatus for cargo handling gas hydrate pellets in the form of pellets made of gas hydrate, the first gas hydrate pellets are stored.
A storage tank, a slurry manufacturing apparatus for mixing the gas hydrate pellets taken out from the first storage tank and a slurry mother liquor to form a slurry, and a slurry transfer means for transferring the slurry manufactured by the slurry manufacturing apparatus, It comprises a solid-liquid separator for separating the slurry transferred by the slurry transfer means into a slurry mother liquor and gas hydrate pellets, and a second storage tank for storing the gas hydrate pellets separated by the solid-liquid separator. Gas hydrate cargo handling equipment.

(9) The gas hydrate according to (8), wherein the gas hydrate pellets and the slurry mother liquor are mixed in a pipe from the first storage tank storing the gas hydrate pellets to the solid-liquid separation device. Rate handling equipment.

(10) The gas hydrate pellets and the slurry mother liquor are mixed in a mixing tank arranged in a path from the first storage tank storing the gas hydrate pellets to the solid-liquid separator. (8) The gas hydrate cargo handling device described in (8).

(11) The gas hydrate cargo handling device according to (8), wherein the gas hydrate pellets and the slurry mother liquor are mixed in a first storage tank storing the gas hydrate pellets.

(12) The gas hydrate cargo handling device according to (9), (10) or (11), wherein the first storage tank is a tank on land or a hold of a ship.

(13) The gas hydrate cargo handling device according to (8), wherein the second storage tank is a hold of a ship or a tank on land.

Here, as the gas constituting the gas hydrate, for example, argon, krypton, nitrogen, oxygen, methane, xenon, hydrogen sulfide, carbon dioxide gas, ethane,
Propane and the like are known.

As the slurry mother liquor, if it is a liquid at the temperature of cooling or at the time of cargo handling, a substance that volatilizes into a gas at the time of storage can be applied without any safety problem.

For example, the slurry mother liquor of natural gas hydrate is a hydrocarbon which has a boiling point higher than that of methane and is liquid at room temperature or below room temperature, in other words, minus 20 ± 10 ° C. to plus 0 ± 10. One or a mixture of hydrocarbons (eg, butane, isobutane, neopentane) that are liquid at 0 ° C. and gas at 0 ± 10 ° C. or higher, or natural gas, hydrofluorocarbons, perfluorocarbons, methanethiol, ethanethiol,
It is preferable to use chloroethane, amines and the like that do not require a high-grade solid-liquid separation device and can be directly used as fuel even if they adhere to or remain on the pellets.

The size of the gas hydrate pellets is preferably such that they can be transported by piping and are easily separated from the slurry mother liquor, for example, having a particle size of about 5 to 50 mm.

The shape of the gas hydrate pellets is most preferably spherical, but may be any shape as long as it has a high filling efficiency (storage efficiency) such as a cylindrical shape or a capsule shape. .

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, natural gas hydrate is used as a gas hydrate and liquid propane is used as a liquid refrigerant (mother liquor). The case where it is used is taken as an example. (A) First Embodiment FIG. 1 is a schematic view of a cargo handling apparatus applied to the implementation of the gas hydrate cargo handling method according to the present invention. The cargo handling apparatus 1 includes a first cargo handling apparatus 10a and a second cargo handling apparatus 10a. Cargo handling device 10b
There is.

The first cargo handling device 10a includes a primary pellet storage tank (first storage tank) 11 for storing gas hydrate pellets (hereinafter referred to as GH pellets) b, and GH pellets b.
Of the GH pellets b and a cargo handling line 13 for handling the GH pellets b.

The GH pellets b are gas hydrates formed by the pellet manufacturing apparatus 3 into, for example, a spherical shape, and while the gas hydrate is riding on the conveyor 14 and passing through the direct contact subcooler 15, for example, , After being supercooled to minus 10 ° C to minus 50 ° C, the primary pellet storage tank 11
Stored in. Since the GH pellet b in the primary pellet storage tank 11 is supercooled to -10 ° C to -50 ° C, it can be stored under atmospheric pressure due to the self-preservation effect of the gas hydrate.

The cooling line 12 includes a direct contact subcooler 15, a first circulation pump 16, a first refrigerant storage tank 17, a second circulation pump 18, a first heat exchanger 19, a first valve 20 and a first circulation. The first heat exchanger 19 is constituted by the pipe 21.
Thus, for example, the slurry mother liquor d cooled to minus 50 ° C. rides on the conveyor 14 from the nozzle 22 provided in the direct contact subcooler 15 and is transferred to the GH pellet b.
Is jetted toward the GH pellet b at a temperature of -10 ° C
Supercool to minus 50 ° C. At this time, the first valve 20
Is "open" and the second valve 23 is "closed". In addition, the code | symbol 24 has shown the subcooler main body.

On the other hand, the cargo handling line 13 includes the first refrigerant storage tank 1
7, second circulation pump 18, first heat exchanger 19, second valve 23, first solid-liquid separator 25 and second circulation pipe 26
And the slurry mother liquor d stored in the first refrigerant storage tank 17 passes through the first heat exchanger 19,
For example, it is cooled to -50 ° C.

Next, the primary pellet storage tank (first storage tank) 1
The GH pellet b in 1 is held in the hold of the ship 31 (second storage tank)
The case of loading and unloading 29 will be described.

As shown in FIG. 2, the first and second valves 20
And 23, the first valve 20 is closed and the second valve 23 is opened, the second circulation pump 18 is started, and the slurry mother liquor in the first refrigerant storage tank 17 is connected to the second circulation pipe 26. circulate d. At that time, the slurry mother liquor d is
The heat exchanger 19 cools it to, for example, -50 ° C.

Thereafter, when the valve 27 of the primary pellet storage tank 11 is opened and the GH pellet b in the primary pellet storage tank 11 is sent to the second circulation pipe 26, the GH pellet b
Is -50 ° C circulating in the second circulation pipe 26.
Is mixed with the slurry mother liquor d to form a slurry, and is transported to the first solid-liquid separation device 25 while being supercooled to -10 ° C to -50 ° C by the slurry mother liquor d at -50 ° C. The opening degree of the valve 27 is adjusted so as to have a predetermined slurry concentration.

The GH pellets b transported to the first solid-liquid separator 25 are separated from the slurry mother liquor d, and pass through the duct 28 provided in the first solid-liquid separator 25 to ship 3
It is loaded into the first cargo hold (second storage tank) 29. Funakura 2
GH pellet b in 9 (second storage tank) is minus 10
Since it is supercooled to -50 ° C to -50 ° C, it can be stored under atmospheric pressure due to the self-preserving effect of gas hydrate.

On the other hand, the slurry mother liquor d separated by the first solid-liquid separator 25 is returned to the first refrigerant storage tank 17. GH
For separating the pellet b and the slurry mother liquor d, for example, a wire net 30 or the like is used. Reference numeral 50 indicates a slurry mother liquor replenishment line.

As shown in FIG. 1, a ship 31 having a hold 29 has a cooling facility 3 for cooling the inside of the hold 29 to a predetermined temperature.
2 and the circulation pipe 41 in the second cargo handling device 10b
Equipped with a part of.

The second cargo handling device 10b includes the second refrigerant storage tank 4
2, the third circulation pump 43, the second heat exchanger 44, the second solid-liquid separation device 45, and the third circulation pipe 41, and the slurry mother liquor d stored in the second refrigerant storage tank 42 is
While passing through the second heat exchanger 44, for example, minus 5
Cool to 0 ° C.

Next, a case where the GH pellets b in the hold 29 are loaded into the storage tank 48 on land will be described. In this case, the hold 29 is regarded as the first storage tank, and the storage tank 48 on land is used.
Be regarded as the second storage tank.

As shown in FIG. 3, the third circulation pipe 4 on the land side
When the third circulation pump 43 is driven after connecting the 1a and the third circulation pipe 41b on the ship side, the second refrigerant storage tank 4
The slurry mother liquor d in 2 circulates in the third circulation pipe 41. At this time, the slurry mother liquor d is cooled to, for example, -50 ° C by the second heat exchanger 44.

Then, when the valve 46 of the hold (first storage tank) 29 is opened and the GH pellets b in the hold 29 are sent to the third circulation pipe 41, the GH pellets b circulate in the third circulation pipe 41. While mixing with the slurry mother liquor d at -50 ° C to form a slurry,
It is transported to the second solid-liquid separation device 45 while being supercooled to −10 ° C. to −50 ° C. by the slurry mother liquid d of 0 ° C. The opening degree of the valve 46 is adjusted so as to have a predetermined slurry concentration.

The GH pellets b transported to the second solid-liquid separator 45 are separated from the slurry mother liquor d, and the duct 47
And is unloaded to a land-based storage tank (second storage tank) 48. GH pellets b in the onshore storage tank (second storage tank) 48
Is supercooled to -10 ° C to -50 ° C, it can be stored under atmospheric pressure due to the self-preserving effect of gas hydrate.

On the other hand, the slurry mother liquor d separated by the second solid-liquid separator 45 is returned to the second refrigerant storage tank 42. Further, for the separation of the GH pellet b and the slurry mother liquor d, for example, a wire net 49 or the like is used. Reference numeral 51 indicates a slurry mother liquor replenishment line.

In the above description, the GH is provided in the pipe 26 from the primary pellet storage tank 11 to the first solid-liquid separation device 25, or in the pipe 41 from the hold 31 to the first solid-liquid separation device 45.
Although the case where the pellet b and the slurry mother liquor d are mixed has been described, the primary pellet storage tank 11 or the hold 3
The GH pellet b and the slurry mother liquor d may be mixed in the first example. (B) Second Embodiment FIG. 4 is a schematic diagram of a cargo handling apparatus that employs a system in which the GH pellets b and the slurry mother liquor d are mixed in a slurry tank when cargo handling the GH pellets b.

As shown in FIG. 4, the cargo handling apparatus 10c has a storage tank 61 as a first storage tank, in which, for example, spherically shaped GH pellets b are stored. Storage tank installed on land (first storage tank)
61 and a hold (second storage tank) 63 of the ship described later
Since such a large tank is not economical when used as a pressure vessel, the internal pressure is maintained at about atmospheric pressure. Also, GH
In order to suppress decomposition of the pellet b, the entire cargo handling plant is kept at a low temperature, for example, -15 ° C.

The GH pellets b stored in the storage tank 61 are supplied to the slurry tank 66 via the constant quantity supply valve 64 provided at the bottom of the storage tank 61 and the belt conveyor 65.

On the other hand, the slurry mother liquor d stored in the refrigerant tank 67 is supplied to the slurry tank 6 by the pump 69.
6 is supplied. GH supplied to the slurry tank 66
The pellet b and the slurry mother liquor d are mixed in the slurry tank 66.
It is agitated by an agitator 71 provided in the above to form a slurry. The slurry mother liquor d is
It is cooled to -15 ° C.

The slurry in the slurry tank 66 is pumped up by the pump 72 and transported to the solid-liquid separator 73 through the pipe 81. The solid-liquid separator 73 separates the GH pellets b forming the slurry and the slurry mother liquor d, and the GH pellets b are the cargo hold (second storage tank) 63 of the ship.
And the slurry mother liquor d is returned to the refrigerant tank 67 by the pump 68 and reused.

Although depending on the performance of the solid-liquid separator 73 and the particle size of the pellets, a few percent of the mother liquor d of the slurry adheres to the GH pellets b stored in the hold 63 of the ship. When the slurry mother liquor d adhering to the GH pellets b is dropped, a recovery device 78 composed of a tank 74 and a pump 75 is installed in the lower part of the hold 63, and the recovered slurry mother liquor d is returned to the refrigerant tank 67 and re-used. use.

The GH pellets b stored in the hold 63 of the ship are finally unloaded in the gasification plant 76, heated and gasified, and then converted into natural gas, for example, by the gas-liquid separation device 77. Separated into water, natural gas is used as fuel.

In FIG. 4, 82 is a pipe for returning the slurry mother liquor d separated by the solid-liquid separator 73 to the tank 67, and 8
3 is a pipe that connects the pump 75 of the recovery device and the pipe 82, and a joint 84 that connects and separates the storage tank 61 and the hold 63 of the ship is provided in the middle of the pipe 83.

In this embodiment, the case where the reference numeral 61 is the land storage tank and the reference numeral 63 is the hold of the ship has been described. However, the present invention is not limited to this. For example, the reference numeral 61 is the hold of the ship and the reference numeral 63 is the land storage tank. It can also be considered.

As described above, according to the present invention, the gas hydrate is stored in the form of pellets during storage or transportation by transportation means such as a ship, so that the filling efficiency (storage efficiency) can be improved. Become.

Further, at the time of cargo handling, since the GH pellets b and the slurry mother liquor d are mixed and made into a slurry form and transported by piping, the handling property is improved as compared with the case where they are transported in the form of pellets.

Therefore, the transportation facility between the first and second storage tanks can be simplified and downsized because of the simple structure in which the pump and the piping are the main facilities. In addition, since the degree of freedom in arranging various facilities is high, the space can be effectively used even when installed in ships, vehicles, containers, and the like. Further, depending on the slurry mother liquor, a simple solid-liquid separator is sufficient.

[0059]

As described above, according to the present invention, the following excellent effects can be obtained.

(B) Since the pipeline transportation is required, G
The H pellets are easily transported.

(B) The GH pellet transport device needs to have a closed structure, but since it is a pipeline,
It will inevitably have a closed structure.

(C) In particular, in a ship or the like, in a transportation method such as a belt conveyor system, the space occupied by the device becomes large, so that the ship becomes large in size, but since it becomes a pipeline, the ship is made compact. it can.

(D) In particular, in a ship or the like, the relative position between the onshore facility and the ship is such that the connecting joint connecting them is simple and compact.

(E) The slurry mother liquor always adheres to the GH pellets separated by the slurry separator (solid-liquid separator).
If it is a gas at room temperature and is a hydrocarbon,
Since it can be used as fuel, the slurry separating device can be a simple device such as a vibrating screen.

(F) When the GH pellets are to be stored again when the tank becomes empty, etc., the tank should be at the storage temperature (for example, minus 15 ° C.). Circulating the slurry mother liquor enables efficient cooling.

[Brief description of drawings]

FIG. 1 is a schematic view of a cargo handling apparatus for carrying out a gas hydrate cargo handling method according to the present invention.

FIG. 2 is an explanatory diagram of a loading method.

FIG. 3 is an explanatory diagram of an unloading method.

FIG. 4 is a schematic view of another cargo handling apparatus for carrying out the gas hydrate cargo handling method according to the present invention.

[Explanation of symbols]

11, 31, 61 First storage tank 25, 45, 73 Solid-liquid separator 31, 48, 63 Second storage tank b Gas hydrate pellets d Slurry mother liquor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuichi Kato             Mitsui Shipbuilding No. 1 Hachiman Kaigan Dori, Ichihara City, Chiba Prefecture             Chiba office (72) Inventor Shigeru Nagamori             5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui             Inside the ship company (72) Inventor Yoshikuni Kunitake             5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui             Inside the ship company F-term (reference) 3E072 EA10                 3E073 BB00

Claims (13)

[Claims] 1. When loading a gas hydrate pellet made of gas hydrate, the gas hydrate pellet is mixed with a slurry mother liquor to form a slurry, and the slurry is transferred to a solid-liquid separator, After that, the gas hydrate pellets are separated from the slurry mother liquor by the solid-liquid separation device and stored in a second storage tank. 2. The gas hydrate according to claim 1, wherein the gas hydrate pellets and the slurry mother liquor are mixed in a pipe extending from the first storage tank storing the gas hydrate pellets to the solid-liquid separation device. Cargo handling method. 3. The gas hydrate pellets and the slurry mother liquor are mixed in a mixing tank arranged in a path from the first storage tank storing the gas hydrate pellets to the solid-liquid separator. Item 1. A method for loading and unloading gas hydrate according to Item 1. 4. The gas hydrate loading / unloading method according to claim 1, wherein the gas hydrate pellets and the slurry mother liquor are mixed in a first storage tank in which the gas hydrate pellets are stored. 5. The cargo handling of gas hydrate according to claim 2, 3 or 4, wherein when the first storage tank is emptied, the storage tank is cooled in advance by the slurry mother liquor in preparation for storage of gas hydrate pellets. Method. 6. The gas hydrate cargo handling method according to claim 2, 3, 4, or 5, wherein the first storage tank is a tank on land or a hold of a ship. 7. The gas hydrate loading / unloading method according to claim 1, wherein the second storage tank is a hold of a ship or a tank on land. 8. A cargo handling apparatus for handling pelletized gas hydrate pellets made of gas hydrate, comprising: a first storage tank for storing the gas hydrate pellets; and a gas hydrate pellets taken out from the first storage tank. And a slurry mother liquor to form a slurry, a slurry manufacturing device for transferring the slurry manufactured by the slurry manufacturing device, and a slurry mother liquor and a gas hydrate for the slurry transferred by the slurry transferring device. A gas hydrate loading / unloading device comprising a solid-liquid separator for separating into pellets and a second storage tank for storing the gas hydrate pellets separated by the solid-liquid separator. 9. The gas hydrate according to claim 8, wherein the gas hydrate pellets and the slurry mother liquor are mixed in a pipe extending from the first storage tank storing the gas hydrate pellets to the solid-liquid separation device. Cargo handling equipment. 10. The gas hydrate pellets and the slurry mother liquor are mixed in a mixing tank arranged in a path from the first storage tank storing the gas hydrate pellets to the solid-liquid separator. Item 8. A gas hydrate cargo handling device according to item 8. 11. The gas hydrate cargo handling apparatus according to claim 8, wherein the gas hydrate pellets and the slurry mother liquor are mixed in a first storage tank storing the gas hydrate pellets. 12. The cargo handling apparatus for gas hydrate according to claim 9, 10 or 11, wherein said first storage tank is a tank on land or a hold of a ship. 13. The cargo handling apparatus for gas hydrate according to claim 8, wherein the second storage tank is a hold of a ship or a tank on land.