JP4105671B2 - Natural gas pellet transport ship - Google Patents

Description

  The present invention relates to a natural gas pellet transport ship that transports natural gas by hydrating (pelletizing) the ship.

Conventionally, natural gas transportation by a ship liquefies natural gas at a loading site, loads the liquefied natural gas on a ship and transports it, and unloads the liquefied natural gas from the ship at a landing site.
FIG. 11 is a diagram for explaining a conventional method of transporting natural gas by a ship. FIG. 11 (1) shows the state at the loading site, FIG. 11 (2) shows the way of transportation, and FIG. 11 (3) shows the unloading. Each state on the ground is shown.
As shown in FIG. 11 (1), in the loading place 101, gaseous natural gas sent from the natural gas mining place is liquefied and accumulated in the storage tank 102.

As described in the prior art section of Table 1, the conditions for the generation and storage of liquefaction at this time are as follows: natural gas is in liquid phase, temperature is minus 162 [° C.] or less, and pressure is about 0.025. [MPa] Hereinafter, the means for maintaining the liquefied natural gas is cooling.
When the liquefied natural gas in the storage tank 102 is transported to the consumption place, it is performed as follows.

  First, a liquefied natural gas (LNG) ship 103 is berthed at the loading place 101, and the storage tank 102 and the cargo tank 104 of the LNG ship 103 are connected by a liquid line 105 and a gas line 106. The LNG pump 107 loaded liquefied natural gas into the cargo tank 104 of the LNG ship 103, and the decomposed natural gas was returned to the storage tank 102 of the loading area 101 by the compressor 108 of the gas line 106 (see FIG. 11 (1)). ). The load conditions are listed in the prior art load column in Table 1.

Next, the LNG ship 103 moves from the loading place 101 to the unloading place 111 (see FIG. 11 (2)). This transportation condition is described in the prior art transportation column of Table 1.
Next, the LNG ship 103 is berthed at the landing place 111, the cargo tank 104 of the LNG ship 103 and the storage tank 112 of the landing place 111 are connected by the liquid line 113 and the gas line 114, and the ship side LNG pump 115 of the liquid line 113 is connected. Thus, the liquefied natural gas was unloaded into the storage tank 112 of the landing site 111, and the natural gas decomposed from the storage tank 112 of the loading site 111 to the cargo tank 104 of the LNG ship 103 was returned by the compressor 116 of the gas line 114 (see FIG. 11 (3)). The unloading conditions are listed in the prior art unloading column in Table 1.

According to the above-described conventional natural gas transportation method using a ship, since the cargo is loaded or sailed in the state of liquefied natural gas, the liquefied natural gas may boil off depending on the relationship between pressure and temperature. In particular, when liquefied natural gas is loaded from the storage tank 102 to the LNG ship 103 at the loading place, the boil-off is not a little, and the boil-off is also performed during the loading voyage, and a predetermined amount of liquefied natural gas is used for the ballast voyage. Therefore, there is a disadvantage that a large amount of liquefied natural gas is lost and transport efficiency is deteriorated. Furthermore, it is necessary to consider the refrigeration equipment for making the temperature extremely low and the material for that purpose, and as a result, there is a drawback of increasing the equipment cost.
This invention is made | formed in view of the point mentioned above, and aims at providing the natural gas transport ship which improved transport efficiency.

In order to achieve the above object, a natural gas pellet transport ship according to the first aspect of the present invention is a natural gas pellet transport ship that pelletizes and transports natural gas on the ship, and has a strength equal to or higher than a predetermined pressure. A heat-resistant cargo tank having a refrigerant pipe, a natural gas receiving apparatus that receives natural gas, pelletizes the natural gas on a ship, and puts it into the heat-resistant cargo tank, and a refrigerant pipe of the heat-resistant cargo tank The refrigerant is fed into the heat-resistant cargo cage to cool at a predetermined temperature, and when unloading at the unloading site, hot gas is supplied to the refrigerant pipe to heat the inside of the heat-resistant cargo cage to form the pellets. A heat source device for decomposing natural gas, and a cargo handling means for sending the decomposed natural gas to an unloading site facility.
Moreover, natural gas pellet transport ship according to the claims 2, a ship for loading transport a slurry natural gas hydrate, a slurry natural gas hydrate in cooling and insulation state at a temperature 1 to 8 [° C.] and cargo艙which is insulation to maintain a load means for loading a slurry natural gas hydrate in the cargo艙in cargo area, the cargo slurry natural gas hydrate transport period embarked on艙the cargo艙A cargo handling means comprising a liquid pump that cools and keeps the temperature at a predetermined temperature and unloads the slurry-like natural gas at the landing site is provided.
Further, the invention according to the claims 3, in natural gas pellet transport ship according to claim 1, wherein the receiving natural gas is characterized slurry der Rukoto.

  According to the present invention, in addition to being able to be transported efficiently, since the pelletized natural gas hydrate has a self-preserving effect, it has a relatively low storage pressure as compared with liquefied gas, and therefore it is easy to handle. Specifically, there is an effect that the amount of boil-off during transportation or the like is small and safety is increased. In addition, the decomposition (gasification) of the pelletized natural gas hydrate requires heat input and a certain amount of time, so even if equipment damage occurs during the connection work of the transportation line, a sudden gas blowout occurs. It does n’t happen and it ’s also very safe. Even if the decomposed gas is ignited, the surface of the hydrate is deprived of heat by the heat of decomposition at the time of decomposition, so the progress of the decomposition is suppressed, so that the combustion of the hydrate itself takes place slowly and explodes. There is no fear of this, and there is an effect that it is possible to carry out extremely safe transportation. Therefore, the transportation efficiency is improved and the cargo basket can be manufactured relatively easily.

In addition to efficient transportation, if the temperature control is supercooled, the pelletized natural gas hydrate has a self-preserving effect, so the amount of boil-off can be reduced, transportation efficiency is improved, and Although there is a predetermined pressure, it can be transported at a relatively high temperature compared to conventional liquefied transport, and the liquid pump can be used for loading or unloading, so that the loading efficiency and the unloading efficiency are increased.
In addition to efficient transportation, less boil-off is required, transportation efficiency is improved, transportation is possible at a relatively low pressure during transportation, and loading with a liquid pump is possible during loading. .

Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings.
(First embodiment)
1 to 7 are views for explaining a first embodiment of the present invention. FIG. 1 is a diagram for explaining the entire first transportation system including the natural gas transportation method by a ship of the present invention.

In FIG. 1, a first transport system 1a includes a natural gas mining means 3 installed in a loading area 2 and a gas tank 4a which is a storage facility, a natural gas transport ship 6 provided with a natural gas pellet manufacturing apparatus 5, It comprises a gas storage tank 8 a installed at the unloading site 7, a liquid line 9 a at the loading site 2, and a gas line 10 a at the unloading site 7.
A natural gas transport ship used in such a transport system will be described with reference to FIGS.

  FIG. 2 is a view showing a natural gas transport ship used for natural gas transport by the ship according to the first embodiment of the present invention, and FIG. 2 (1) is a side sectional view showing the natural gas transport ship, FIG. 2 (2) is a system diagram showing a heat source device for cooling and heating a plurality of cargo traps of a natural gas transport ship. FIG. 3 is a plan view showing a natural gas transport ship used for natural gas transport by the ship according to the first embodiment of the present invention. FIG. 4 is a transverse sectional view showing the natural gas transport ship according to the first embodiment.

2 (1) and 3 to 5, the natural gas transport ship 6 is a ship capable of pelletizing and transporting natural gas, and includes the following components.
That is, as shown in FIGS. 2 (1), 3, and 4, the natural gas transport ship 6 has a cargo trap 11 a, 11 a,... The natural gas pellet manufacturing apparatus 5 that receives natural gas, pelletizes it on the ship, and puts it into the cargo container 11a, and cools the cargo containers 11a, 11a,... When unloading, a heat source device 12 capable of decomposing the natural gas pelletized by heating, and a cargo handling means 13 provided in the ship are provided.

  That is, the natural gas transport ship 6 shown in FIGS. 3 to 5 has a hull structure having a double bottom 65, a double hull 66 and a central longitudinal bulkhead 67, and an independent tank-type cargo ship with a heat insulating material 68. 11a is divided into starboard and portsides. The cargo tanks 11a, 11a,... Of these independent tanks are regularly arranged on both sides, and each cargo tank 11a, 11a,. It has strength, and heat insulation is applied to the outer peripheries of the cargo troughs 11a, 11a,. .. Are divided into starboard and portsides, so that the heat exchange of the refrigerant pipes 20 effective for quick heat exchange with the cargo in each of the cargo baskets 11a, 11a,. It is possible to increase the area, and to suppress the rise in the center of gravity due to the influence of the free surface when separated water (water) is present in the cargo trough 11a, so that the stability can be maintained. Further, these cargo troughs 11a, 11a,... Are supported by a double bottom 65, a double hull 66, and a central longitudinal bulkhead 67 via a heat shield supporting joist 69, and each cargo trough 11a, 11a is supported. ,... Have a predetermined curvature and avoid stress concentration due to cooling. In addition, each cargo cage 11a, 11a,... Is provided with a pressure / temperature / liquid level gauge 40 and a safety valve 41, and detects the environment inside each cargo cage 11a, 11a,. It is configured to be controllable to a predetermined value.

2 (2), the heat source device 12 includes a compressor 15 used for freezing and heating, an oil separator 16, a condenser 17, a liquid receiver 18, an expansion valve 19, The refrigerant pipe 20 is provided with a pipe that connects them, and a valve that determines a pipe path or closes the pipe.
The discharge side of the compressor 15 communicates with the oil separator 16 through a pipe 22 provided with a valve 21. The outlet of the oil separator 16 is branched into a valve 23 and a valve 25 through a pipe 24, and can further communicate with the condenser 17 through the valve 25. The outlet of the condenser 17 can communicate with the liquid receiver 18 by a pipe 27 having a valve 26. The outlet of the liquid receiver 18 is connected to a pipe 29 provided with a valve 28.

One end of the refrigerant pipe 20 is connected to the pipe 29 via an electromagnetic valve 30 and an expansion valve 19. One end of the refrigerant pipe 20 is connected to a pipe 33 via an electromagnetic valve 31. The pipe 33 is connected to a pipe 39 provided with a valve 35 via a valve 34.
The other end of the refrigerant pipe 20 is connected to the pipe 24 via an electromagnetic valve 36. One end of the pipe 39 communicates with the suction port of the compressor 15.
As shown in FIGS. 2 (2), 3 and 4, the refrigerant pipe 20 is arranged to cool the cargo ledges 11a, 11a,..., And the inner wall of the cargo ledge 11a as shown in FIG. It is covered with. As shown in FIG. 4, a refrigerant pipe protector 38 is provided inside the cargo tub 11 a of the refrigerant pipe 20 and further inside the refrigerant pipe 20.

Further, as shown in FIG. 3, the cargo traps 11 a, 11 a,... Of the natural gas transport ship 6 are provided with pressure / temperature / liquid level gauges 40, 40,. ,... And thermal barrier hatches 42, 42,.
As shown in FIG. 2 (1), the natural gas transport ship 6 is provided with an engine room 43, a refrigeration machine room 44, a pump room 47, and the like.

FIG. 5 is a system diagram showing the cargo handling means provided in the natural gas transport ship used in the natural gas transport method by the ship according to the first embodiment of the present invention.
As shown in FIG. 5, the cargo handling means 13 provided in the natural gas transport ship 6 includes a gas conduit system 45 that guides natural gas, and a drain pipe system 46 that guides water separated from the slurry-like natural gas. Consists of.

Here, in the gas conduit system 45, a pipe 49 provided with a valve 48 communicates with the cargo container 11 a, and this pipe 49 communicates with the common pipe 50. The pipes 49, 49,... Are provided so as to correspond to the cargo troughs 11a, 11a,. In addition, a connection pipe 51 is connected to the common pipe 50, and a valve 52 is provided at the end of the connection pipe 51.
Further, the drain pipe system 46 includes liquid pumps 55, 55, valves 56, 56 provided on the suction side of the liquid pumps 55, 55, and pipes 57, 57,... Communicating with the cargo troughs 11a, 11a,. , Valves 58, 58,... Provided on the pipes 57, 57,... And valves 59, 59 provided on the cargo cage 11a side of the pipes 58, respectively.

FIG. 6 is a diagram for explaining the principle of the natural gas pellet manufacturing apparatus used in the natural gas transport ship used in the first embodiment of the present invention.
In FIG. 6, the natural gas pellet manufacturing apparatus 5 includes a production vessel 60, a stirrer 61, a water supply / drainage device 62, a transfer pump 63, and a dehydration device 64, and is configured as follows.
Natural gas is supplied to the production container 60. Further, water is supplied to the production container 60 from a water supply / drainage device 62. Inside the production vessel 60, stirring is performed by a stirrer 61. The lower part of the generation container 60 is communicated with the suction part of the transfer pump 63. The discharge part of the transfer pump 63 is communicated with the dehydrator 64. The dehydrator 64 is communicated with the water supply / drainage device 62.

  First, water is introduced into the production container 60 from the water supply / drainage device 62, pressurized natural gas is supplied to the production container 60, set to a predetermined temperature and pressure, and stirred with a stirrer 61 as necessary, and hydrate (slurry) Natural gas). At this time, the slurry hydrate produced in the mixed state of water and hydrate is transferred to the dehydrator 64 by the transfer pump 63. In the dehydrator 64, water is dehydrated from the slurry hydrate and formed into pellets, and the separated water is sent to the water supply / drainage device 62, and is returned again to the production container 60 by the water supply / drainage device 62.

Here, “hydrate” means that natural gas is solidified with water, and water molecules are formed by hydrogen bonding in the same tetrahedral arrangement as ice (under low temperature and high pressure). An inclusion compound in which gas molecules are incorporated in a cage structure. The “slurry” is a suspension of liquid and solid particles, which is in a state where fluidity of 10 to 20000 [centipoise] is obtained by mixing hydrate and liquid. “Pellets” are, for example, cubes or spheres in order to increase the density of the slurry, which is mainly hydrated by removing water, and further compress it to increase the density and load easily. It is the one molded into the same.
A natural gas transportation method by a ship in such a transportation system will be described with reference to FIG. 7 based on FIGS.

FIG. 7 is a process diagram showing a natural gas transportation method by a ship according to the first embodiment of the present invention. FIG. 7 (1) shows a loading process, FIG. 7 (2) shows a transportation process, and FIG. 3) explains the unloading process.
In FIG. 7, the natural gas transportation method by a ship according to the first embodiment of the present invention is a method of transporting by natural gas transport ship (ship) in which natural gas is pelletized. According to the conditions shown in 1, the natural gas pelletized by the following steps is transported.

  Next, in the first step, the gas tank 4a which is a storage facility for the loading site 2 and the natural gas pellet manufacturing apparatus 5 provided on the natural gas transport ship 6 are communicated with each other at the loading site 2 through the gas line 9a. As a result, the natural gas is received by the natural gas pellet manufacturing apparatus 5 on the natural gas transport ship 6, and the natural gas pellet manufacturing apparatus 5 converts the natural gas into pellets, and the pelletized natural gas is transported by natural gas. The cargo is loaded on the cargo trough 11a previously cooled to minus 15 [° C.] of the ship 6 (see FIG. 7 (1)). The conditions at this time are as shown in the section of generation in the column of Example 1 in Table 2. The state of natural gas is pellets, the temperature is minus 15 [° C.] or less, and the pressure is 0. The manufacturing means is a cooling and stirring type, a spray type or a bubbling type.

  Next, in the natural gas transport ship 6, when the pelletized natural gas is filled in the cargo tank 11a, the thermal hatch 42 of the cargo tank 11a is closed, the natural gas pellet manufacturing apparatus 5 is removed from the thermal hatch 42, and the next The natural gas pellet manufacturing apparatus 5 is moved to the position of the cargo basket 11a, the natural gas pellet manufacturing apparatus 5 is connected to the thermal barrier hatch 42, the thermal barrier hatch 42 is opened, and the pellets are loaded on the cargo rack 11a again. This is repeated, and when all cargo traps 11a, 11a,... Are filled with natural gas pellets, preparation for transportation is completed.

  Next, in the second step, the pellets loaded on the cargo troughs 11a, 11a,... Are transported while being cooled at a predetermined temperature under a predetermined pressure (see FIG. 7 (2)). The conditions at the time of transportation are as described in the transportation section of Example 1 column of Table 2, the state of natural gas is pellets, and the temperature in the cargo trough 11a is minus 15 [° C] or less, The pressure in the cargo container 11a is kept at 0.025 [MPa] or less, and the cargo container 11a is cooled and kept warm.

  As shown in FIG. 7 and subsequent figures, the third process starts when the natural gas transport ship 6 arrives at the landing 7 and comes in contact with the berth. In the third step, first, the gas conduit system 45 of the cargo handling means 13 of the natural gas transport ship 6 is connected to the gas line 10a of the unloading place 7 to connect the cargo ridge 11a of the natural gas transport ship 6 with the unloading place 7. The storage tank 8a, the valves 25 and 37 and the solenoid valve 30 of the heat source device 12 are closed, and the valves 23 and 34 and the solenoid valves 31 and 36 are opened to enable supply of hot gas to the refrigerant pipe 20. Then, the compressor 15 is operated, hot gas is supplied to the refrigerant pipe 20 and heated, the pelletized natural gas is decomposed and loaded into the storage tank 8.

As described in the section of unloading in the column of Example 1 in Table 2, the conditions for this unloading are such that the state of the natural gas is gaseous, the temperature of the cargo trap 11a is kept at room temperature, and the gasification and The means for carrying is to heat and pump.
The natural gas stored in the storage tank 8a is in a gaseous state, the storage temperature is room temperature, and the storage means is a pressure tank as shown in the storage section of the column of Example 1 in Table 2. is there.

Since the first embodiment is operated as described above, it can be efficiently transported, and if the temperature control is supercooled, the hydrate has a self-preserving effect, so the boil-off amount is small. , Transportation efficiency is improved.
Further, in the first embodiment, a relatively low temperature is required, but since the pressure can be kept low, the freight rod 11a can be manufactured relatively easily.

(Second Embodiment)
FIG. 8 is a diagram for explaining the entire second transportation system including the natural gas transportation method by the ship of the present invention.
In FIG. 8, the second transport system 1b includes a natural gas mining means 3 installed in the loading area 2, a facility 4b for generating and storing slurry, and a natural gas transport ship 6 capable of transporting slurry-like natural gas. The slurry storage tank 8b installed at the unloading site 7, the liquid line 9b at the loading site 2, and the cargo handling means 10b at the unloading site 7.

Further, in the second embodiment, the natural gas transport ship 6 is different from the first embodiment only in that the natural gas transport ship 6 is provided with a cargo trough 11b capable of storing slurry-like natural gas. This is the same as in the first embodiment.
A natural gas transportation method by a ship using such a second transportation system will be described with reference to FIG.

FIG. 9 is a process diagram showing a natural gas transportation method by a ship according to the second embodiment of the present invention. FIG. 9 (1) shows a loading process, FIG. 9 (2) shows a transportation process, and FIG. 3) explains the unloading process.
The natural gas transport method by ship according to the second embodiment of the present invention is a method of transporting natural gas in a slurry (Slurry) form and transporting by ship. According to the conditions shown in Example 2 of Table 3, The natural gas in the form of a slurry is transported by the above process.

  First, the conditions of generation, storage, and loading at the loading site 2 will be described. As shown in Example 2 in Table 3, the state of natural gas is in a slurry state, and its temperature is, for example, 1 to 8 [° C.]. For example, the pressure is 0.3 [MPa] or less, and the loading means uses a liquid pump.

  In the loading area 2, natural gas in a slurry state is stored in the facility 4b. In the first step, the facility 4b and the cargo trap 11b of the natural gas transport ship 6 communicate with each other using the liquid line 9b and the gas conduit system 45 of the cargo handling means 13, and are connected to the liquid pump 70 of the liquid line 9b. Are loaded into the cargo baskets 11b, 11b,... (See FIG. 9 (1)). The conditions at this time are as shown in the column of Example 2 in Table 1 for production, storage, and cargo. The state of natural gas is slurry, the temperature is maintained at, for example, 1 to 8 [° C.], and the pressure Also, for example, it is kept at 0.3 [MPa] or less. The loading means is a liquid pump 70.

In the natural gas transport ship 6, when the slurry-like natural gas is filled in the cargo container 11b, the cargo container 11b is supplied to the other cargo container 11b, and when all the cargo containers 11b are filled, the next process is started.
In the next second step, the slurry-like natural gas loaded in the cargo troughs 11b, 11b,... Is transported while being cooled at a predetermined temperature under a predetermined pressure (see FIG. 9 (2)). The conditions at the time of transportation are as described in the transportation section in the column of Example 2 of Table 3, the state of the natural gas is in a slurry state, and the temperature in the cargo trough 11b is, for example, 1 to 8 [° C.]. And the pressure in the cargo trough 11b is maintained at, for example, 0.3 [MPa] or less. Each cargo trough 11b is cooled and kept warm.

  As shown in FIGS. 5 and 8, the third process is started when the natural gas transport ship 6 arrives at the landing site 7 and comes in contact with the berth. In the third step, first, the drainage pipe system 46 and the gas line 45 of the cargo handling means 10 b communicate with the cargo tank 11 b of the natural gas transport ship 6 and the storage tank 8 b of the unloading site 7, and are unloaded by the pump 55. As for the conditions for this unloading, as described in the unloading section in the column of Example 2 in Table 3, the state of the natural gas is in a slurry state, and the temperature of the cargo trough 11b is maintained at, for example, 1 to 8 [° C.]. At the same time, the pressure of the cargo trough 11b is maintained at, for example, 0.3 [MPa] or less. Moreover, as a means to convey, it is the transfer by the liquid pump 55.

Since the second embodiment is operated as described above, it can be efficiently transported, and if the temperature control is supercooled, the hydrate has a self-preserving effect, so the boil-off amount is small. , Transportation efficiency is improved.
Further, in the second embodiment, although it is at a predetermined pressure, it can be transported at a relatively high temperature, and a liquid pump can be used for loading or unloading. Therefore, loading efficiency and unloading efficiency are improved. Get higher.

(Third embodiment)
FIG. 10 is a diagram showing a third transportation system according to the third embodiment of the present invention. In FIG. 10, the third transportation system 1 c is configured such that the loading system 2 according to the second embodiment (the natural gas mining means 3 of the loading site 2, the facility 4 b for slurry generation and storage, and The liquid line 9b) is adopted, the natural gas pellets are produced in the natural gas transport ship 6 and then transported, and the unloading place 7 uses the unloading method (the storage tank 8a and gas of the unloading place 7) in the first embodiment. Line 10a) is employed.

In short, the third transport system 1c uses the natural gas mining means 3, the slurry generation and storage facility 4b and the liquid line 9b on the loading site 2 side, and the gas line 10a and the storage tank 8a on the loading site 7 side. use. A feature of the third embodiment is that a pellet is produced in the cargo tank 11a of the natural gas transport ship 6.
First, the conditions for generation, storage, and loading at the loading site 2 will be described. As shown in Example 3 of Table 1, the state of natural gas is in a slurry state, and its temperature is, for example, 1 to 8 [° C.]. For example, the pressure is 0.3 [MPa] or less, and the loading means uses a liquid pump.

In the loading area 2, natural gas in a slurry state is stored in the facility 4b. In the first step, the facility 4b and the cargo trap 11a of the natural gas transport ship 6 are connected using the liquid line 9b and the gas conduit system 45 of the cargo handling means 13, and are connected to the liquid pump 70 of the liquid line 9b. Are loaded into the cargo baskets 11a, 11a, ... (see Fig. 9 (1)).
The conditions at this time are as shown in the section of Example 3 in Table 4 for the production, storage, and loading items. The state of natural gas is slurry, the temperature is maintained at, for example, 1 to 8 [° C.], and the pressure Also, for example, it is kept at 0.3 [MPa] or less.
In the natural gas transport ship 6, when the slurry-like natural gas is filled in the cargo container 11a, the cargo container 11a is supplied to the other cargo container 11a, and when all the cargo containers 11a are filled, the next process is started.

  Next, in the first half of the second step, only water is drained from the slurry-like natural gas in the cargo tank 11a by the liquid pump 55, and the inside of the cargo tank 11a is cooled by the refrigerant pipe 20 of the heat source device 12. To do. Here, as shown in the drainage section in the column of Example 3 in Table 4, the drainage conditions are such that the natural gas is in a slurry state, and the temperature is, for example, 1 to 8 [° C], for example, 0.3 [MPa. The liquid pump 55 drains the water decomposed by heat input from the slurry state.

  Moreover, as described in the pellet section in the column of Example 3 in Table 4, the conditions after the pellets are natural gas is pellets, and the inside of the cargo trough 11a is, for example, minus 15 [° C.]. The cargo cage 11a is kept at 0.025 [MPa] or less, and the cargo cage 11a is cooled and kept warm. By maintaining such conditions, pellets are generated in the cargo container 11a in the first half of the second step.

Then, in the second half of the second step, the pelletized natural gas is transported from the loading site 2 to the unloading site 7 by the natural gas transport ship 6 (see FIG. 7 (2)).
As described in the column of Example 1 in Table 2 and the transportation section of Example 3 in Table 4, the condition at the time of transportation is that the state of natural gas is pellets, and the temperature in the cargo tub 11a is, for example, Below minus 15 [° C.], the pressure in the cargo cage 11a is maintained at, for example, 0.025 [MPa] or less, and the cargo cage 11a is cooled and kept warm.

  The third process starts when the natural gas transport ship 6 arrives at the landing 7 and comes in contact with the dock. In the third step, first, the gas conduit system 45 of the cargo handling means 13 of the natural gas transport ship 6 is connected to the gas line 10a of the unloading place 7 to connect the cargo ridge 11a of the natural gas transport ship 6 with the unloading place 7. , The valves 25 and 37 and the electromagnetic valve 30 of the heat source device 12 are closed, and the valves 23 and 34 and the electromagnetic valves 31 and 36 are opened to enable supply of hot gas to the refrigerant pipe 20. Then, the compressor 15 is operated, hot gas is supplied to the refrigerant pipe 20 and heated, the pelletized natural gas is decomposed and loaded into the storage tank 8a.

  As described in the section of unloading in the column of Example 1 in Table 1, the conditions for this unloading are such that the state of natural gas is gaseous, the temperature of the cargo tub 11a is kept at room temperature, and gasification and The means for carrying is heating and pressure feeding (see FIG. 7 (3)). The conditions for unloading are as described in the column of unloading in Example 1 in Table 2 and Example 3 in Table 4.

Since the third embodiment is operated as described above, it can be efficiently transported, and if the temperature control is supercooled, it has a hydrate self-preserving effect, so the boil-off amount is small. , Transportation efficiency is improved.
In the form of the third embodiment, it can be transported at a relatively low pressure during transportation, and can be loaded with a liquid pump at the time of loading and can be efficiently loaded.

  The present invention is used when natural gas is made into pellets and efficiently transported by ship.

It is a figure for demonstrating the whole 1st transport system including the natural gas transport method by the ship of this invention. It is a figure which shows the natural gas transport ship used for the natural gas transport method by the ship which concerns on the 1st Embodiment of this invention, FIG.2 (1) is a sectional side view which shows a natural gas transport ship, FIG. 2) is a system diagram showing a heat source device for cooling and heating a plurality of cargo traps of a natural gas transport ship. It is a top view which shows the natural gas transport ship used for the natural gas transport method by the ship which concerns on the 1st Embodiment of this invention. It is a transverse section showing the natural gas transport ship concerning a 1st embodiment of the present invention. It is a systematic diagram which shows the cargo handling means provided in the natural gas transport ship used for the natural gas transport method by the ship which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the principle of the natural gas pellet manufacturing apparatus used with the natural gas transport ship used for the 1st Embodiment of this invention. It is process drawing which shows the natural gas transport method by the ship which concerns on the 1st Embodiment of this invention, FIG. (1) is a loading process, FIG. (2) is a transport process, FIG. (3) is an unloading process. , Respectively. It is a figure for demonstrating the whole 2nd transport system containing the natural gas transport method by the ship of this invention. It is process drawing which shows the natural gas transportation method by the ship which concerns on the 2nd Embodiment of this invention, FIG. (1) is a loading process, FIG. (2) is a transportation process, FIG. (3) is an unloading process. , Respectively. It is a figure which shows the 3rd transport system which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the natural gas transportation method by the conventional ship, a figure (1) is a state in a loading place, a figure (2) is in the middle of transportation, a figure (3) is a state in an unloading place, Each is shown.

Explanation of symbols

1a ... 1st transportation system,
1b ... second transport system,
1c ... third transport system,
2 ... loading area,
3 ... Natural gas mining means,
4a: Gas tank as storage facility,
4b ... (slurry production and storage) facilities,
5 ... Natural gas pellet manufacturing equipment,
6 ... Natural gas transport ship,
7: Unloading place,
8a, 8b ... storage tanks,
9a, 9b ... liquid lines (loading side),
10a, 10b ... gas lines (on the landing side),
11a, 11b ... Cargo trap,
12 ... Heat source device,
13 ... Handling means,
15 ... Compressor,
16 ... oil separator,
17 ... condenser,
18 ... liquid receiver,
19 ... expansion valve,
20 ... refrigerant pipe,
21 ... Valve,
22 ... Piping,
23 ... Valve,
24 ... Piping,
25 ... Valve,
26 ... Valve,
27 ... Piping,
28 ... Valve,
29 ... Piping,
30 ... Solenoid valve,
31 ... Solenoid valve,
33 ... Piping,
34 ... Valve
35 ... Valve,
36 ... Solenoid valve,
38 ... Refrigerant tube protector,
39 ... piping,
40: Pressure, temperature, level gauge,
41 ... safety valve,
42 ... thermal barrier hatch,
43 ... Engine room
44 ... Refrigeration machine room,
45 ... gas conduit system,
46 ... drainage pipe system,
47: Pump room,
48 ... Valve,
49 ... Piping,
50 ... Common piping,
51 ... Connection piping,
52 ... Valve,
55 ... Liquid pump,
56 ... Valve,
57 ... Piping,
58 ... Valve,
59 ... Valve,
60 ... generating container,
61 ... Agitator,
62 ... water supply / drainage device,
63 ... transfer pump,
64 ... dehydration device,
65 ... double bottom,
66 ... double hull,
67 ... central longitudinal partition wall,
68 ... heat insulating material,
69... Joist for supporting heat insulating material,
70 ... Liquid pump,
101 ... loading area,
102 ... Storage tank,
103 ... LNG ship,
104 ... cargo tank,
105 ... Liquid line,
106 ... gas line,
107 ... LNG pump,
108 ... Compressor,
111 ... unloading ground,
112... Storage tank,
113 ... Liquid line,
114 ... gas line,
115 ... ship side LNG pump,
116... Compressor

Claims (3)

A natural gas pellet transport ship for pelletizing and transporting natural gas,
A heat-resistant cargo cage having a strength equal to or higher than a predetermined pressure and provided with a refrigerant pipe;
A natural gas pellet manufacturing apparatus for receiving natural gas, pelletizing the natural gas on a ship, and feeding the pellet into the heat-resistant cargo tank;
The refrigerant is sent to the refrigerant pipe of the heat-resistant cargo tub to cool the heat-resistant cargo ridge at a predetermined temperature, and when unloading at the landing site, hot gas is supplied to the refrigerant pipe to evacuate the inside of the heat-resistant cargo tub. A heat source device for heating and decomposing the pelletized natural gas;
A natural gas pellet transport ship comprising cargo handling means for sending the decomposed natural gas to the unloading site facility. A ship that loads and transports slurry-like natural gas hydrate ,
A heat- insulated cargo cage that maintains the slurry-like natural gas hydrate at a temperature of 1 to 8 [° C.] in a cooled and heat-retaining state ;
Loading means for loading the slurry-like natural gas hydrate into the cargo shed at the loading place;
During the transportation period of the slurry-like natural gas hydrate loaded in the cargo tank, the cargo tank is cooled and kept at a predetermined temperature, and
A natural gas pellet transport ship comprising a cargo handling means provided with a liquid pump for unloading slurry-like natural gas at an unloading site. Natural gas, natural gas pellet transport ship according to claim 1, wherein the slurry der Rukoto receiving said.

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