JP2004263803A - Gas hydrate storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas hydrate storage tank which is large and can be manufactured at low cost. <P>SOLUTION: The gas hydrate storage tank is composed of a plurality of unit tanks 6 where a plurality of partitions 5 are arranged at a predetermined interval in the tank main body 1 covered with a heat insulating material 3. A bottom of each unit tank 6 is made in a funnel shape and is provided with an outlet 9 connected to a drain device 19. In each unit tank 6, a temperature sensor 14 is arranged, and carry-in entrances for a cold/hot medium and gas hydrate are provided. A temperature signal of the temperature sensor 14 is introduced to a controller 15 so as to control the supply amount of the cold/hot medium. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a gas hydrate storage tank for storing a so-called gas hydrate composed of a gas mainly composed of methane such as natural gas and water, and water.
[0002]
[Prior art]
Conventionally, transportation and storage of natural gas are performed in the form of liquefied natural gas (LNG) or compressed natural gas (CHG).
[0003]
By the way, since LNG needs to be transported or stored while keeping the cargo temperature at minus 162 ° C., an expensive tank is required for transport and storage. In addition, the production requires a lot of energy, and if the temperature control is malfunctioning, it evaporates rapidly, which is very dangerous. Further, as described above, since the temperature is extremely low, the vaporization rate is high, and it is not suitable for long-term storage.
[0004]
For this reason, as a clean energy source and a raw material of various structures, gas hydrate (hereinafter, referred to as NGH) composed of a gas mainly composed of methane, such as natural gas, and water has attracted attention in recent years. Means for production and transportation have been proposed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-2000-304196 (page 2-3, FIG. 1)
[0006]
[Problems to be solved by the invention]
By the way, it is necessary to temporarily store the NGH at a manufacturing site of the NGH, a transit point, a consumption point, and the like. A storage tank for storing NGH must be large in size and inexpensive from the economical point of view, and in recent years the development of an NGH storage tank in consideration of this point has been strongly desired by the industry. is there.
[0007]
[Means for Solving the Problems]
The present invention has been made in view of such a situation, and a plurality of unit tanks are configured by arranging a plurality of partition walls at predetermined intervals in a tank body covered with a heat insulating material. The bottom of the unit tank is formed in a funnel shape, and a discharge port is provided below the unit tank. A gas hydrate storage tank characterized in that a temperature signal of a sensor is introduced into a control device to control a supply amount of the cooling / heating medium.
[0008]
As described above, according to the present invention, since a plurality of unit tanks are formed in the tank body and the bottom surface thereof is formed in a funnel shape, not only can the NGH be easily discharged, but also the dead space at the bottom of the tank body can be reduced. Space can be reduced. As a result, the amount of storage in the NGH in the storage tank can be increased.
[0009]
The plurality of unit tanks are configured to supply the gas hydrate and the cooling / heating medium, respectively, and the supply amount of the cooling / heating medium is detected by a temperature sensor disposed in each unit tank. Is controlled and the inside temperature of each unit tank is maintained at a predetermined temperature, so that the workability when carrying in the gas hydrate can be improved, and the gas hydrate can be stably stored for a long period of time. Become.
[0010]
(2) In the gas hydrate storage tank of the present invention, a communication hole having an opening / closing valve is provided in each partition, and a predetermined unit tank is connected to a cooling / heating medium supply facility to be supplied to the unit tank. The cooling / heating medium is supplied to another unit tank through the communication hole.
[0011]
According to such a configuration, first, a predetermined unit tank is cooled to a predetermined temperature, for example, about −25 ° C., by the cooling / heating medium supplied from the cooling / heating medium supply equipment, and then the unit tank is cooled. The on-off valve provided on the partition wall between the tank and the adjacent unit tank is opened to supply the cooling / heating medium to the adjacent unit tank. Hereinafter, this operation is sequentially repeated, and the unit tanks are sequentially cooled to a predetermined temperature. As a result, when the predetermined unit tank is cooled to the predetermined temperature, the NGH can be loaded into the predetermined unit tank, so that the efficiency of the NGH loading operation can be improved.
[0012]
(3) In the gas hydrate storage tank of the present invention, a cold / hot medium supply pipe having one end connected to a cold / hot medium supply facility is extended so as to be located in each unit tank, and A hot medium supply pipe is opened in each unit tank, and a discharge port having an on-off valve is provided, and further, the on-off valve is controlled by a control signal of a control device so that the cooling / heating medium is supplied to a predetermined unit tank. It is characterized by supplying.
[0013]
According to such a configuration, of the plurality of unit tanks constituting the storage tank body, the selected unit tank is cooled as the first unit tank, and the NGH is carried into the selected arbitrary unit tank. Therefore, the workability of the NGH loading operation can be further improved.
[0014]
(4) Further, the gas hydrate storage tank of the present invention is characterized in that a heat insulating material is arranged on each partition.
[0015]
According to the gas hydrate storage tank configured as described above, since each unit tank constituting the storage tank is protected from heat by the heat insulating material, it is possible to reduce the cooling time when loading the NGH into the predetermined unit tank. In addition to the above, when the NGH in a predetermined unit tank is carried out, cooling of the unit tank becomes unnecessary. As a result, the cooling efficiency can be improved.
[0016]
(5) In the gas hydrate storage tank of the present invention, a pressure sensor is provided in each unit tank and a cracked gas discharge port is provided, and the open / close valve of the cracked gas discharge port is controlled based on a pressure signal from the pressure sensor. It is characterized by doing.
[0017]
According to the gas hydrate storage tank configured as described above, since the pressure in each unit tank is detected by the pressure sensor, the inside of each unit tank becomes higher than a predetermined pressure due to generation of decomposition gas or supply of a heating medium. When this happens, it can be discharged from the decomposition gas discharge port to maintain the inside of each unit tank at a predetermined pressure. Therefore, the storage tank can have a light structure, and as a result, the tank body can be constructed at low cost.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a gas hydrate storage tank according to the present invention, and FIG. 2 is a view taken along the line AA ′ of FIG.
[0019]
As shown in FIG. 1, the tank main body 1 of the gas hydrate storage tank 100 includes an inner wall 2, a heat insulating material 3 covering the inner wall 2, and an outer wall 4 surrounding the heat insulating material 3. A plurality of partition walls 5a, 5b, 5c ~ are arranged at predetermined intervals inside the inside, and a plurality of unit tanks (unit tanks) 6a, 6b, 6c, 6d ~ are formed. The upper portions of the unit tanks 6a, 6b, 6c, 6d are supported by columns 30. The support 30 is connected to the inner wall 2 and the partition 5 by a fastener 31 such as a tie rod.
[0020]
The bottom surface 7 constituting a part (bottom) of the unit tanks 6a, 6b, 6c, 6d is formed in a funnel shape having an inclination angle equal to or larger than the repose angle of NGH. Further, discharge ports 9a, 9b, 9c, 9d and the like having on-off valves (not shown) are provided at the lowermost portion of the bottom surface 7. The inclination angle of the funnel-shaped bottom surface 7 is appropriately set according to the state of the NGH so that the stored NGH is automatically discharged from the discharge ports 9a, 9b, 9c, 9d when the on-off valve is opened. . That is, the NGH may be stored in the form of sherbet, powder, granules, pellets, or slurry using antifreeze, and these NGHs have different angles of repose.
[0021]
The partition walls 5a, 5b, 5c ~ have communication holes 10a, 10b, 10c ~ having on-off valves 11a, 11b, 11c ~ on the upper part thereof, and the unit tank is opened by opening the on-off valves 11a, 11b, 11c ~. 6a, 6b, 6c, 6d and so on communicate with each other. Then, for example, cold air or hot air A is supplied to the most upstream unit tank 6a from a cold / hot medium supply facility 12 such as an air conditioner.
[0022]
In the figure, 14a, 14b, 14c, 14d~ the unit tank 6a, 6b, 6c, a temperature sensor is disposed within 6D～, the temperature signal _{V 1, V 2, V 3} , V 4 ~ control is introduced to the apparatus 15, the control signals _{V 11, V 12, V 13} from the controller 15, on-off valve 11a, 11b, 11c~ is adapted to be controlled respectively by ~. Further, the unit tanks 6a, 6b, 6c, 6d to are provided with a pressure adjusting discharge valve (not shown) at the upper part thereof.
[0023]
In the figure, reference numeral 16 denotes an NGH supply pipe which can carry the NGH 18 into predetermined unit tanks 6a, 6b, 6c, 6d ~ by opening and closing the on-off valves 17a, 17b, 17c, 17d ~. Reference numeral 19 denotes an unloading device disposed below the unit tanks 6a, 6b, 6c, 6d. Depending on the state of NGH, for example, a belt conveyor, a screw conveyor, a slurry tube, or the like is used. The unloading device 19 is covered with the heat insulating material 3 as necessary.
[0024]
Next, a case where NGH is carried into a gas hydrate storage tank and stored will be described.
[0025]
As shown in FIG. 3, first, the cooling / heating medium supply facility 12 is started, and for example, the cold air A at −25 ° C. to −10 ° C. is supplied into the unit tank 6a at the uppermost stream. At this time, the on-off valve (not shown) of the discharge port 9a and the on-off valve 11a of the partition 5a are closed. In this case, the pressure in the unit tank 6a increases, but the pressure can be prevented by the operation of the discharge valve (not shown).
[0026]
When the inside of the unit tank 6a reaches a predetermined temperature (for example, minus 20 ° C.), the on-off valve 17a of the NGH supply pipe 16 is opened, and the NGH 18 is loaded into the unit tank 6a, and at the same time, the on-off valve 11b of the partition 5b is opened. When the unit tank 6b is opened, the cool air A is introduced into the unit tank 6b to cool the unit tank 6b to a predetermined temperature.
[0027]
When a predetermined amount of the NGH 18 is carried into the unit tank 6a, the on / off valve 17a is closed and the on / off valve 17b is opened to carry the NGH 18 into the unit tank 6b.
[0028]
Hereinafter, the NGH 18 is sequentially carried into the unit tanks 6c and 6d to be stored in a similar manner. In this case, the control of the on-off valves 17a, 17b, 17c and 17d is performed by a control signal from the control device 15.
[0029]
As described above, in the loading and storage of the NGH, the loading operation can be started by cooling only the uppermost unit tank 6a to a predetermined temperature without cooling the entire tank body 1, so that the speed of the loading operation can be improved. Work efficiency can be improved.
[0030]
The NGH 18 stored in the unit tank bodies 6a, 6b, 6c, 6d is stored while being cooled to a constant temperature for a predetermined period. The cooling temperature (cooling temperature) is preferably from -25C to -10C. That is, it is known that natural gas hydrate (NGH) containing methane as a main component is usually stable at normal pressure by setting the temperature to -25 ° C to -10 ° C.
[0031]
Therefore, by cooling to the above-mentioned temperature and storing, the inside of each unit tank main body 6a, 6b, 6c, 6d ~ can be made normal pressure. This means that the unit tank bodies 6a, 6b, 6c, 6d and so on, in other words, the tank body 1 does not need to be a pressure-resistant shell, and the structure can be made light. As a result, the tank body 1 can be manufactured at low cost. Of course, when the temperature in each of the unit tanks 6a, 6b, 6c, 6d is out of the predetermined range during the storage process, the temperature is detected by the temperature sensors 14a, 14b, 14c, 14d, and the temperature is reduced. The heating medium supply equipment 12 is controlled.
[0032]
Next, a case in which the NGH 18 stored in the unit tanks 6a, 6b, 6c, 6d is carried out will be described.
[0033]
When the NGH 18 in the unit tank 6a is carried out, as shown in FIG. 4, when the on-off valve (not shown) of the discharge port 9a is opened, the NGH 18 in the unit tank 6a is discharged from the discharge port 9a by its own weight through the discharge device 19. It is dropped and discharged. At this time, by supplying the cool air A into the unit tank 6a by the heat medium supply equipment 12, it is possible to prevent the internal pressure from lowering and maintain the cooling temperature.
[0034]
The unloading of the NGH 18 can be arbitrarily performed from any of the unit tanks 6a, 6b, 6c, 6d. In that case, the open / close valves 11a, 11b, 11c- may be appropriately operated to supply the cool air A to the selected unit tanks 6a, 6b, 6c, 6d-.
[0035]
FIG. 5 is a cross-sectional view of the second embodiment of the gas hydrate storage tank, and the same parts as those of the first embodiment described above are denoted by the same reference numerals and detailed description thereof will be omitted.
[0036]
In this embodiment, a cooling / heating medium supply pipe 20 connected to a cooling / heating medium supply facility 12 is provided at a lower portion of the tank body 1. The cooling / heating medium supply pipe 20 is provided with discharge ports 22a, 22b, 22c, 22d- having on-off valves 21a, 21b, 21c, 21d- for each of the unit tanks 6a, 6b, 6c, 6d-. ing.
[0037]
On the other hand, an NGH supply pipe 23 is provided above the unit tanks 6a, 6b, 6c, 6d,. The NGH supply pipe 23 is also provided with supply ports 25a, 25b, 25c, 25d, which have on-off valves 24a, 24b, 24c, 24d, for each of the unit tanks 6a, 6b, 6c, 6d. Here, 26a, 26b, 26c ~ are fans provided in the communication holes 10a, 10b, 10c ~.
[0038]
In the case of this example, one or more of the selected unit tanks 6a, 6b, 6c, 6d- can be simultaneously cooled by opening any of the on-off valves 21a, 21b, 21c, 21d-. . Then, by opening the on-off valves 24a, 24b, 24c, 24d ~ of the corresponding unit tanks 6a, 6b, 6c, 6d ~, the NGH 18 is carried in and stored in the cooled unit tanks 6a, 6b, 6c, 6d ~. can do. Further, the ventilation between the unit tanks 6a, 6b, 6c, 6d- can be performed quickly by operating the fans 26a, 26b, 26c- as required.
[0039]
By the way, when decomposed gas is generated, a pressure sensor (not shown) is installed for each of the unit tanks 6a, 6b, 6c, 6d, and based on signals from the respective pressure sensors, the unit tanks 6a, 6b , 6c, 6d to operate the open / close valves (not shown) to release the decomposition gas from the unit tanks 6a, 6b, 6c, 6d to the outside of the unit tanks. Of course, the decomposed gas may be guided to an NGH manufacturing device (not shown) if necessary and stored again as NGH 18.
[0040]
In the above-described embodiment, the case where the unit tanks 6a, 6b, 6c, and 6d are arranged in the horizontal direction has been described, but the unit tanks 6 may be joined in the vertical and horizontal directions, for example, as shown in FIG. . 6a, 6b, 6c- and 60a, 60b, 60c- indicate unit tanks. This arrangement is particularly suitable when the tank body 1 is large.
[0041]
In addition, by providing a heat insulating material to the partition walls 5a, 5b, 5c and so on, for example, when discharging the NGH 18 from a specific unit tank, only the unit tank storing the NGH 18 may be cooled to a predetermined temperature. The required energy can be reduced.
[0042]
When the NGH is decomposed, the cooling / heating medium supply equipment 12 is switched to use hot air. Then, NGH is decomposed in the storage tank 100 to take out natural gas. Also, when performing maintenance and inspection of the storage tank 100, hot air is required to remove the remaining NGH.
[0043]
【The invention's effect】
As described above, the present invention configures a plurality of unit tanks by arranging a plurality of partition walls at predetermined intervals in a tank body covered with a heat insulating material, and the bottom surface of each unit tank is funnel-shaped. In addition, a discharge port connected to the discharge device is provided at the lower part, furthermore, a temperature sensor is disposed in each unit tank, and a carry-in port for a cooling / heating medium and a gas hydrate is provided, and a temperature signal of the temperature sensor is transmitted to the control device. Since the supply amount of the cooling / heating medium is controlled by introduction, it is possible to easily maintain a predetermined temperature in each unit tank, to improve workability when carrying in NGH, and to achieve stable operation for a long time. NGH storage becomes possible.
[0044]
Further, since the temperature in each unit tank is controlled, NGH can be stored at normal pressure. As a result, the storage tank main body can be made lighter in structure, and the storage tank main body can be constructed inexpensively, thereby providing a great effect.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a gas hydrate storage tank according to the present invention.
FIG. 2 is a sectional view taken along line AA ′ of FIG.
FIG. 3 is an explanatory view of carrying in a gas hydrate.
FIG. 4 is an explanatory diagram of gas hydrate discharge.
FIG. 5 is a schematic sectional view showing another example of the gas hydrate storage tank according to the present invention.
FIG. 6 is a perspective view showing still another example of the gas hydrate storage tank according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tank main body 2 Inner wall 3 Insulation material 4 Outer walls 5a, 5b, 5c Partition walls 6a, 6b, 6c, 6d Unit tank 7 Bottom surface 9a, 9b, 9c, 9d Outlets 10a, 10b, 10c Communication holes 11a, 11b, 11c, 17a , 17b, 17c, 17d, 21a, 21b, 21c, 21d On-off valve 12 Heat medium supply equipment 14a, 14b, 14c, 14d Temperature sensor 15 Control device 16 NGH supply pipe 18 NGH
19 Discharge device 20 Heat medium supply pipes 22a, 22b, 22c, 22d Release port 23 Supply pipe 30 Prop 31 Fastening material

Claims (5)

A plurality of partition walls are arranged at predetermined intervals in a tank body covered with a heat insulating material to form a plurality of unit tanks, and the bottom surface of each unit tank is funnel-shaped and connected to a discharge device below the unit tank. A discharge port is provided, and further, a temperature sensor is disposed in each unit tank, and a carry-in port for a cold / hot medium and a gas hydrate is provided. A gas hydrate storage tank characterized by controlling a supply amount. A communication hole having an open / close valve is provided in each partition, and a predetermined unit tank is connected to a cooling / heating medium supply facility, and the cooling / heating medium supplied to the unit tank is supplied to another unit tank via the communication hole. The gas hydrate storage tank according to claim 1, wherein the gas hydrate is supplied to the storage tank. A cold / hot medium supply pipe, one end of which is connected to the cold / hot medium supply equipment, is extended so as to be located in each unit tank, and the cold / hot medium supply pipe is opened in each unit tank, and 2. A gas hydrate storage tank according to claim 1, further comprising a discharge port having an on-off valve, and further comprising controlling the on-off valve by a control signal of a control device to supply the heat medium to a predetermined unit tank. . 3. The gas hydrate storage tank according to claim 1, wherein a heat insulating material is disposed on each partition. 2. The gas hydrate storage according to claim 1, wherein a pressure sensor is provided in each unit tank and a cracked gas discharge port is provided, and an open / close valve of the cracked gas discharge port is controlled based on a pressure signal of the pressure sensor. tank.

Images