WO2003006589A1

WO2003006589A1 - Method of pelletizing, handling and transporting gas hydrate

Info

Publication number: WO2003006589A1
Application number: PCT/JP2002/005224
Authority: WO
Inventors: Tatsuya Takaoki; Shigeru Nagamori; Yuichi Kato; Takashi Arai
Original assignee: Mitsui Engineering & Shipbuilding Co., Ltd.
Priority date: 2001-07-09
Filing date: 2002-05-29
Publication date: 2003-01-23
Also published as: JP4167977B2; AU2002306357B2; RU2004103553A; JPWO2003006589A1; RU2276128C2; AU2002306357B9

Abstract

Powdery gas hydrate is compression-molded and palletized by a pelletizing device. Thereafter, the solid gas hydrate is loaded into a ship or in a storage tank in a storage facility.

Description

Specification

Granulation and cargo handling of gas hydrate and transportation method

The present invention relates to a method of granulating, loading and transporting a so-called gas hydrate composed of gas mainly composed of gas such as natural gas and water, and a method of granulating, loading and transporting the gas hydrate. About.

Visual technology

Traditionally, the transport and storage of natural gas has been carried out in the form of liquefied natural gas (hereinafter LNG) or compressed natural gas.

However, LNG needs to be transported and stored at a cargo temperature of minus 16 2 ° C, and special vessels (LNG carriers) with expensive tanks specially manufactured for transport and storage are required. Storage facilities are required. In addition, a lot of energy needs to be put into production in order to make the liquid a negative 16 2 ° C. In addition, LNG is dangerous because it quickly evaporates if the control goes wrong. In addition, LNG is not suitable for long-term storage because it has a high vaporization rate due to extremely low temperature as described above.

On the other hand, natural gas and other gases mainly containing natural gas have attracted attention as clean energy sources and raw materials for various structures, and methane, such as natural gas, is mainly used for transportation and storage. Gas as a component is artificially or industrially Research into slate is underway.

Gasuhai Doreto is Ri Contact with a crystal structure molecules gas is within one by one in the basket to make the water molecules, for example, in the main Tanhai Doreto, meta Nhai Dre 1 m ³ at normal pressure It is said that 164 m ³ of methane can be stored in the area (the volume of water is 0.8 m ³ ).

As described above, methane hydrate has high gas storability and is attracting attention as a new natural gas transport and storage alternative to LNG. The methane gas density in the methane hydrate is about 3.5 times lower than that of LNG. However, for man-made or industrial production, the liquefaction temperature (minus 16 It is said that energy efficiency is greatly improved because it is not necessary to cool to below C).

When methane hydrate is manufactured artificially, for example, water or antifreeze is sprayed from a spraying means into a pressure vessel maintained at a temperature of 1 to 10 ° (:, pressure: 30 to: 100 atm). And natural gas (methane) is supplied from the supply pipe, and water or antifreeze sprayed from the spraying means and natural gas (methane) are synthesized to produce powdery methane hydrate. Powdered methane hydrate has a low filling rate (volume of methane hydrate / volume of storage container), so it is large for transportation and storage. A sunset having a large volume is required.

In addition, when stored in large quantities for a long period of time, powdered gas hydrates have a problem in that they are combined with each other by their own weight and become rock-like, making it difficult to remove (unload) them.

Disclosure of the invention

The present invention has been made in view of such conventional problems, and aims at improving the filling rate of gas hydrates, safety during transportation and storage, and ease of handling during loading. It is an object of the present invention to provide a method for granulating, handling, and transporting a gas hydrate whose properties can be measured.

In order to solve the above-mentioned problems, a method for granulating a gas hydrate of the present invention is characterized in that a powdery gas hydrate is compression-molded by a granulator to form a pellet.

Further, in the gas hydrate loading and unloading method of the present invention, a powdery gas hydrate is compression-molded by a granulator to form a pellet, and thereafter, the solidified gas hydrate is stored in a tank of a ship or a storage facility. It is characterized by loading in

Here, before the powdery gas hydrate is processed into a pellet, it is preferable to spray a liquid on the gas hydrate in advance to wet the gas hydrate. Also, solidified gas It is preferable to spray a liquid on the hydrate to moisten it and then supercool it. It is also preferable to mix two or more types of pelletized gas hydrates with different dimensions and load them on ships or storage facilities. Further, it is preferable that the diameter ratio of two or more kinds of pellet-shaped gas hydrates having different dimensions is set to 1.5 to 30.

On the other hand, in the gas hydrate transportation method of the present invention, the powdered gas hydrate is compression-molded by a granulator to form a pellet, and thereafter, the solidified gas hydrate is shipped or stored. It is loaded into the storage tank of the facility and transported at a predetermined temperature.

Here, it is preferable to keep the storage temperature of the pellet-shaped gas hydrate at −5 ° C. to −30 ° C.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory view showing a method for granulating and loading gas hydrate according to the present invention.

FIG. 2 is an enlarged front view including a partial cross section of the pelletizer.

FIG. 3 is a cross-sectional view of the transfer device.

FIG. 4 is an explanatory diagram of a gas hydrate manufacturing method. FIG. 5 is an explanatory diagram of a case where two types of gas hydrates, large and small, are mixed. Fig. 6 is an explanatory diagram for loading on a tank truck.

FIG. 7 is a sectional view of the carrier.

FIG. 8 is a sectional view showing another example of the carrier.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing a method of granulating and loading a gas hydrate according to the present invention. A brief description of how to make a drate artificially is provided.

Methane hydrate can be produced by two methods, a dry method and a wet method. When it is produced by a wet method, for example, it is produced by an apparatus shown in FIG.

This device is composed of a cylindrical container 101, the temperature in the container 101 is maintained at 1 to 100 ° C, and the pressure is maintained at 30 to 100 atm. The water or antifreeze sprayed from the spraying means 112 is combined with natural gas (methane) supplied from the supply pipe 108 in the reaction section 101A to form powdered methane a. Generates and falls to the surface of water or antifreeze in storage section 101B. The powdered methane hydrate a floating on the surface of water or antifreeze is discharged sequentially by the scraper 114. It is attracted to 107 and discharged from outlet 107. The powdery medium a discharged from the discharge port 107 is stored in a storage tank (not shown) after removing excess water or antifreeze.

In the figure, 103 is a cooling jacket, 106 is a coolant supply line, 102 is a coolant outlet line, 104 is a water or antifreeze draining line, and 105 is water. Or, a circulation line for antifreeze, 110 is a circulation pump, 111 is a line for extracting water or antifreeze, and 113 is a supply line for water or antifreeze.

Next, a method for granulating and handling a gas hydrate according to the present invention will be described with reference to FIG.

In FIG. 1, 1 is a storage tank for storing powdered methane hydrate a, 2 is a horizontal screw conveyor provided at the bottom of the storage tank 1, and screw conveyor 2 is It comprises a cylindrical main body 3 and a screw shaft 4 actively driven by an electric motor 5. The main body 2 has a downward duct 6 on the lower surface of the tip.

Immediately below the duct 6, a pelletizer (granulator) 7 including two rollers 8a and 8b is provided. The mouth roller 8a rotates clockwise in the figure, and the mouth roller 8b rotates counterclockwise in synchronization with the roller 8a. As shown in FIG. 2, hemispherical depressions 9 are provided at regular intervals in the circumferential direction on the outer peripheral surfaces of the rollers 8a and 8b, respectively. The shape of the depression 9 is not limited to a hemisphere, but may be a desired shape such as a semi-elliptical sphere or a semi-column. The size is also set to an arbitrary size. The pelletizer is not limited to the roller type described above, and other types may be used.

Referring back to FIG. 1, a water injection nozzle 10 is provided between duct 6 and pelletizer 17. Further, a horizontal transfer device 11 is provided immediately below the pelletizer 17. The transfer device 11 includes a belt conveyor 11 and a box-shaped main body 13. The main body 13 has a hopper 14 directly below the pelletizer 17 and has a downward duct 15 on the lower surface of the tip. The main body 13 of the transfer device 11 has a water injection nozzle 10a provided downstream of the hopper 14. The tip of the water injection nozzle 10 a faces the upper surface of the belt conveyor 1.

Further, the main body 13 has a cooling jacket (not shown) on the outside thereof, so that the conveyed object conveyed by the belt conveyor 12 is supercooled. The belt conveyor 12 is held by two or three rollers 16 at one location so as to maintain a dynamic angle of repose (see Fig. 3). The space between the duct 6 of the screw conveyor 2 and the hopper 14 of the transfer device 11 is sealed with a cover (not shown) so that the vaporized gas does not leak to the outside.

Next, the case where the methane hydrate (NGH) is loaded on a carrier (bulk carrier) and transported will be described.

As shown in Fig. 1, the duct 15 of the transfer device 11 is inserted into the cargo port 32 of the bulk carrier 30 (load tank) 31 and then the screw conveyor 2 When the electric motor 5 is driven, the powdered medium a in the storage tank 1 is supplied to the pelletizer 17 by the horizontal screw-comparator-2.

The powdery methane hydrate a supplied to the pelletizer 17 is compression-molded by two rollers 8 a and 8 b having a hemispherical recess 9 on the outer peripheral surface, and the spherical shape ( It is formed into a ball-shaped) meta hydrate b. If the wetness of the powdery medium hydrate a is insufficient, water c is sprayed from the water injection nozzle 10 to wet the powdery hydrate a. Then, the tightening of the powdered metal nose plate a becomes firm and hard to break even if dropped.

The ball-shaped methane hydrate (hereinafter referred to as the methane hydrate ball) b is from the pelletizer 17 It is supplied onto the belt conveyor 12 of the transport device 11. For example, when loading into a large carrier (bulk carrier) 30 hold (load tank) 31, the main body 13 of the transport device 11 is used. Water c is sprayed from the water injection nozzle 10a provided at the methane hydrate ball b on the belt conveyor 12 and supercooled to -5 ° C to -20 ° C.

Then, the outer surface of the methane hydrate ball b is covered with an ice film (capsule), the strength of the methane hydrate ball b further increases, and a large carrier (bulk carrier) 30 holds (load tank). It will be harder to break even if loaded on 31 and less crushed by its weight when loaded in large quantities.

The powdery gas hydrate a has a self-preserving property because it has a crystal structure in which one gas molecule is contained in the water created by water molecules. In addition, covering the outer surface of the metal hydrate ball b with an ice film (capsule) has the advantage of further improving self-preservation.

The methane drain balls b, whose outer surface is covered with an ice film, are loaded into the hold (load tank) 31 of the bulk carrier 30 by the belt conveyor 12. The hold (load tank) 31 has a temperature lower than the temperature at which the methanhydrate pole b decomposes (for example, minus 5 ° C Minus 30 ° C).

As the bulk carriers 30, those shown in Figs. 7 and 8 are preferably used. The bulk carrier 30 in FIG. 7 has a loading conveyor 33 and a discharging conveyor 35. In addition, it has a baffle plate and hatch 38 for evenly loading gas hydrate balls b. The baffle plate / hatch 38 moves up and down. In the figure, 31 is the hold, 34 is the gate, 36 is the ballast tank, 37 is the cover, and 39 is the insulation.

On the other hand, the bulk carrier 30 shown in Fig. 8 has a cargo handling machine 50 that can move in the bow direction. 31 is the hold, 37 is the cover, and 39 is the insulation.

In the above explanation, the case where the methane drain pole b is loaded into the hold (loading tank) 31 by the belt conveyor type transfer device 11 has been described. ) When directly loading to 31, a pneumatic transport system may be used as the transport device.

Also, when loading methane hydrate ball b into tank lorry 40, it is also loaded into tank 41 of tank opening 40 by belt-conveyor-type transfer device 11 as in the case of a ship (Fig. See Figure 6). Also, when storing high-battery balls b in storage facilities, As in the case of the tank lorry, the sheet is conveyed by a belt-conveyor type conveying device 11.

The size of the metahydrate ball b may be from a few centimeters to a few tens of centimeters, and sometimes about a few meters. The larger the size, the lower the surface area ratio and the less bridging occurs, resulting in a higher filling rate. The filling rate of the methane hydrate pole b granulated as described above is about 60%. Incidentally, since the filling rate of the powdery gas hydrate is 40%, it can be seen that the filling rate is greatly improved by granulating the gas hydrate.

Fig. 5 shows a method to further improve the filling rate of the hydrated ball. In other words, this is a method of combining a methane hydrate pole b, which has a large particle diameter, with a pelletizer 17, and a pelletizer 17, which manufactures a methane hydrate ball b "with a small particle diameter. This method attempts to fill the space (1 filling rate) created by a large methane hydrate drain b 'with a small methane hydrate drain b'. If this method is adopted, the filling rate of the gas hydrate is further improved to about 80%.

What is important here is the ratio of the diameter of the large meth- nate hydrate ball b 'to the diameter of the small methane hydrate ball b "(diameter ratio = large methane hydrate drain). The diameter of the ball / diameter of the small-sized metal hydrate pole). According to the experiment

The diameter ratio is preferably in the range of 1.5 to 30, more preferably in the range of 5 to 20.

When the diameter ratio is less than 1.5, the filling rate does not increase because the small metal hydrate ball b "does not enter the space of the large metal hydrate ball b. If it exceeds 30, the number of small-sized methane hydrate balls b "increases, and bridging tends to occur, so that the filling rate does not increase. In addition, the diameter of the metahedrate pole b other than spherical, such as an elliptical sphere, is

The diameter of the inscribed sphere.

If this method is adopted, the size of the cargo hold (loading tank) and the tank of the evening crawler will be less than one-half that of the case where the powder of the powder is loaded. Further, the number of types of the methane hydrate balls is preferably two or more. For example, if the number of the methane hydrate poles is three, large, medium, and small, the filling rate can be further improved.

As described above, by employing the present invention and maintaining the temperature lower than the temperature at which the methane hydrate ball decomposes, the contact area between adjacent methane hydrate balls is small, so that the The late balls maintain a sintered state. Therefore, the aggregate of the transported methanehydrate balls can be easily crushed, and can be unloaded with a grab or the like.

In the above description, a case where methane hydrate balls are loaded in a hold or a tank lorry has been described. However, the present invention can also be applied to a case where methane hydrate balls are stored in the evening of a storage facility.

The present invention is also applicable to granulation, cargo handling, storage and transportation of gas hydrates other than methane, such as propane and carbon dioxide.

As described above, according to the present invention, a gas hydrate can be made into a solid having uniform shape and quality by industrially pelletizing a powdery gas hydrate. This dramatically increases the fluidity of the gas hydrate, making it easier to handle and transport.

In addition, the present invention makes it possible to industrially pelletize a powdery gas hydrate, so that the filling rate is significantly improved as compared with the gas hydrate of powder, and the economics of transportation and storage can be secured. Became.

In addition, the gas hydrate has a crystal structure in which gas molecules are contained one by one in a basket made of water molecules, so it rapidly evaporates even if the temperature control becomes abnormal. It is safer than LNG. In addition, because of the slow vaporization rate, longer-term storage than LNG Suitable for warehouse.

Further, since the contact area of the ball-shaped gas hydrate is small, the ball-shaped gas hydrate maintains a sintered state. For this reason, the aggregate of ball-shaped gas hydrates collected during transportation or storage can be easily crushed, and can be easily unloaded using, for example, a grab.

The present invention also provides a method for forming an ice film (force capsule) on the surface of a ball-shaped gas hydrate by spraying water onto the ball-shaped gas hydrate and supercooling the ball-shaped gas hydrate. Strength is increased and it is hard to break. Therefore, a large amount of the gas hydrate can be transported and stored.Moreover, according to the present invention, two or more types of ball-shaped gas hydrates having different dimensions are mixed and loaded. The filling rate can be further improved as compared with the case of loading.

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention having the above-described excellent effects can be extremely effectively used for granulation, cargo handling and transportation of gas hydrate.

Claims

The scope of the claims

1. A method for granulating a gas hydrate, wherein a powdery gas hydrate is compression-molded into a pellet by a granulator.

2. The gas hydrate is characterized in that the powdery gas hydrate is compression-molded by a granulator to form a pellet, and then the solidified gas hydrate is loaded into the tanks of ships and storage facilities. Loading method.

3. The gas hydrate loading and unloading method according to claim 2, wherein a liquid is sprayed on the gas hydrate to wet the gas hydrate before the powdery gas hydrate is added in a pellet form.

4. The gas hydrate loading and unloading method according to claim 2, wherein the solidified gas hydrate is sprayed with a liquid to moisten the liquid, followed by supercooling.

5. The gas hydrate according to any one of claims 2 to 4, wherein two or more types of gas hydrates having different dimensions are mixed and loaded into a storage tank of a ship or a storage facility. Cargo handling method.

6. The method for loading and unloading gas hydrate according to claim 5, wherein the diameter ratio of two or more kinds of gas hydrates having different dimensions is set to 1.5 to 30.

7. The powdery gas hydrate is compression-molded into pellets by a granulator and then solidified. A method of transporting gas hydrate, comprising loading the hydrated gas hydrate into a storage tank of a ship or storage facility and transporting the hydrate at a predetermined temperature.

8. The method for transporting gas hydrate according to claim 7, wherein the storage temperature of the gas hydrate in the form of pellets is maintained at -5 ° C to -30 ° C.