JP2020200763A - Separation and recovery device and gas hydrate recovery system - Google Patents

Abstract

To provide a separation and recovery device and a gas hydrate recovery system allowing for further improvement of efficiency.SOLUTION: A separation and recovery device comprises: a separation pipe into which sediment including gas hydrate and fluid including seawater are introduced; an inducer which is arranged in the separation pipe and rotates around the axis of the separation pipe to cause separation in the flow of the fluid and separate the gas from the gas hydrate; a drive unit which rotates at least the inducer; a discharge pipe which is connected to the separation pipe on the radial outside of the inducer and which discharges the fluid to the outside by centrifugation generated by the inducer; a pressure-feeding unit which is provided on the downstream side of the inducer in the separation pipe and rotates around the axis of the separation pipe to thereby feed the gas, under pressure; and a recovery pipe which is connected to the separation pipe on the downstream side of the pressure-feeding unit and recovers the gas.SELECTED DRAWING: Figure 9

Description

The present invention relates to a separation and recovery device and a gas hydrate recovery system.

In a recovery system for recovering gas hydrate such as methane hydrate, gas hydrate mined at the bottom of the sea or the like is generally pumped onto the water through a riser pipe or the like.
Methane hydrate is an icy solid in which methane molecules are surrounded by water molecules under low temperature and high pressure conditions. Since most of the weight of methane hydrate is water as described above, it is desired to separate methane from methane hydrate on the seabed and recover it as methane gas to improve the collection efficiency.
Gas separation from gas hydrate requires heating or depressurization. However, on the deep sea floor, the atmospheric pressure is very high, and there are many technical problems in reducing the gas hydrate. Therefore, it is considered realistic to use a method using an inhibitor that changes the heating or chemical stable state.

Patent Document 1 discloses a system for supplying a laser beam from the sea to the seabed as heat energy for heating methane hydrate. In Patent Document 1, methane hydrate is irradiated with a laser beam and heated on the seabed to separate methane gas from methane hydrate, and floating methane gas is collected.
Patent Document 2 describes a facility for separating methane gas from methane hydrate on water instead of on the seabed. In the equipment of Patent Document 2, methane hydrate is heated by utilizing the exhaust heat of the prime mover in order to eliminate the energy supply from the outside.

Japanese Patent No. 3506696 Japanese Patent No. 4968998

The system described in Patent Document 1 described above uses a laser beam to heat the gas hydrate, but there is a problem that the driving energy of the laser light source becomes large and it is difficult to improve the efficiency.
On the other hand, the system described in Patent Document 2 uses waste heat to improve efficiency, but it is not possible to obtain sufficient heat energy for gas separation only by using waste heat, and it is necessary to inject other heat energy. There is.
Further, the exhaust heat used in Patent Document 2 is cooled on the way to the bottom of the water such as the deep sea bottom. Therefore, it is difficult to apply the system described in Patent Document 2 to gas separation performed on the seabed.

The present invention has been made in view of the above circumstances, and provides a separation / recovery device and a gas hydrate recovery system capable of further improving efficiency.

The following configuration is adopted to solve the above problems.
According to the first aspect of the present invention, the separation / recovery device is arranged in the separation pipe into which a sediment containing gas hydrate and a fluid containing seawater are introduced, and rotates around the axis of the separation pipe. By doing so, the inducer that causes separation in the flow of the fluid to separate the gas from the gas hydrate, at least the drive unit that rotates the inducer, and the separation pipe on the radial outer side of the inducer. A discharge pipe that is connected and discharges the fluid to the outside by centrifugation by an inducer, and a pressure feed that is provided on the downstream side of the inducer in the separation pipe and rotates about an axis to pump the gas. A unit and a recovery pipe connected to the separation pipe on the downstream side of the pumping unit to recover the gas.
As described above, the gas hydrate is depressurized by rotating the inducer at high speed in the fluid to cause peeling. Therefore, the gas can be separated from the gas hydrate. Furthermore, due to centrifugation by the inducer, deposits with a relatively large specific gravity move outward in the radial direction of the inducer, while gas having a relatively low specific gravity moves inward in the radial direction of the inducer. Then, the centrifuged sediment is discharged to the outside from the discharge pipe on the radial outer side of the inducer. Further, the gas separated from the gas hydrate is sent to the pumping unit. Then, it is compressed by the pumping unit and sent to, for example, on the water via a recovery pipe.
Therefore, as compared with the case where the gas is separated from the gas hydrate mainly by heating, the gas can be separated efficiently by depressurizing. Further, since the gas hydrate is depressurized by utilizing the separation of the fluid due to the rotation of the inducer, the gas hydrate can be depressurized easily and surely even on the deep sea bottom.

According to the second aspect of the present invention, the separation / recovery device according to the first aspect may include a heating unit capable of heating the fluid introduced into the separation tube.
With this configuration, both decompression and heating of gas hydrate can be performed. As a result, the gas can be efficiently separated from the gas hydrate.

According to the third aspect of the present invention, the heating unit according to the second aspect may heat the inducer by the exhaust heat of the driving unit.
With this configuration, the exhaust heat of the drive unit can be effectively utilized to heat the gas hydrate with the inducer.

According to the fourth aspect of the present invention, the gas hydrate recovery system includes a separation recovery device according to any one of the first to third aspects, a mining device for mining the gas hydrate, and the mining device. It is provided with a transfer pipe for transferring the gas hydrate mined by the above to the separation / recovery device, and a collection / collection pipe for collecting the gas recovered by the separation / recovery device.
With this configuration, the gas can be separated from the mined gas hydrate, and the separated gas can be moved to the water or the like via a lift pipe and recovered.
Therefore, it is not necessary to raise the sediment to the surface of the water, so that the efficiency of gas recovery can be improved.

According to the separation recovery device and the gas hydrate recovery system, further efficiency improvement is possible.

It is a block diagram which shows the schematic structure of the gas hydrate recovery system in the reference example of this invention. It is a schematic block diagram of the separation recovery apparatus in the reference example of this invention. It is a figure which shows the introduction process of the separation recovery apparatus in the reference example of this invention. It is a figure which shows the decompression process of the separation recovery apparatus in the reference example of this invention. It is a figure which shows the recovery process of the separation recovery apparatus in the reference example of this invention. It is a figure which shows the discharge process of the separation recovery apparatus in the reference example of this invention. It is a schematic block diagram corresponding to FIG. 2 in the modification of the reference example of this invention. It is a block diagram which shows the schematic structure of the gas hydrate recovery system in embodiment of this invention. It is a schematic block diagram of the separation recovery apparatus in embodiment of this invention. It is a developed view which saw the blade of the inducer in embodiment of this invention from the outside in the radial direction. It is a schematic block diagram of the separation recovery apparatus in the modification of embodiment of this invention. It is a schematic block diagram of the separation recovery apparatus in another aspect of embodiment of this invention.

Next, the separation recovery device and the gas hydrate recovery system in the reference example of the present invention will be described with reference to the drawings.
(Reference example)
FIG. 1 is a configuration diagram showing a schematic configuration of a gas hydrate recovery system in a reference example of the present invention.
In this reference example, a gas hydrate recovery system that recovers gas from methane hydrate as a gas hydrate will be described as an example. Further, in this reference example, a case where methane hydrate existing on the deep sea bottom (for example, a water depth of about 1000 m) is excavated and collected together with earth and sand will be described. The methane hydrate to be collected may be either a sand layer type or a surface layer type.

As shown in FIG. 1, the gas hydrate recovery system 1 of this reference example includes a mining machine (mining device) 2, a transfer pipe 3, a separation and recovery device 4, a riser pipe (lifting pipe) 5, and lifting. Mainly equipped with a mother ship 6.
The mining machine 2 crushes and inhales the sediment containing methane hydrate deposited on the seabed. Further, the mining machine 2 crushes the sucked sediment and supplies the crushed sediment to the separation / recovery device 4 via the transfer pipe 3.

The transfer pipe 3 is a pipe for transferring the deposit containing the gas hydrate mined and crushed by the mining machine 2 to the separation and recovery device 4. The transfer pipe 3 has an inner diameter that allows smooth transfer of crushed sediment, and has sufficient pressure resistance for use on the seabed. Here, a pump or the like for pumping the sediment may be provided at the inlet of the transfer pipe 3, but the pump of the transfer pipe 3 can be omitted if the self-sufficiency action of the separation / recovery device 4 can be sufficiently obtained. ..

The separation / recovery device 4 separates methane gas from methane hydrate contained in the sediment transferred through the transfer pipe 3. Further, the separation / recovery device 4 discharges the deposit T2 from which the methane gas has been separated to the outside. Further, the separation / recovery device 4 sends the separated methane gas to the riser pipe 5.

FIG. 2 is a schematic configuration diagram of a separation / recovery device in a reference example of the present invention.
As shown in FIG. 2, the separation / recovery device 4 in this reference example includes a separation device main body 7, a drive unit 8, and a heating unit 9. In FIG. 2, for convenience of illustration, the separation device main body 7 is shown upside down.
The separation / recovery device 4 in this reference example includes a plurality of separation device main bodies 7, and more specifically, three separation device main bodies 7.
The separating device main body 7 mainly includes an accommodating portion 10 and a reciprocating moving portion 11.
The accommodating portion 10 forms a separation space B inside the accommodating portion 10. Here, the separation space B means a space for separating methane gas from methane hydrate.
More specifically, the accommodating portion 10 is formed, for example, in a bottomed cylindrical shape, and a separation space B is formed by the inner peripheral surface 10a thereof and the end surface 11a of the reciprocating moving portion 11.

The accommodating unit 10 has an introduction port P1, a collection port P2, and a discharge port P3.
The introduction port P1 is a port in which the valve (described later) is opened when the reciprocating moving portion 11 is in the first position (described later). A transfer pipe 3 is communicated with the introduction port P1, and when the valve of the introduction port P1 is opened, deposits containing methane hydrate can be introduced into the separation space B. Here, this sediment also contains seawater.

The recovery port P2 is a port for discharging the methane gas separated from the methane hydrate to the outside of the accommodating portion 10. The recovery port P2 is opened when the reciprocating moving portion 11 is in the second position where the volume of the separation space B is larger than that in the first position and the pressure is reduced. A riser pipe 5 is connected to the recovery port P2, and when the recovery port P2 is opened, the methane gas M in the separation space B flows into the riser pipe 5.

The discharge port P3 is a port for discharging the deposit T2 (including seawater) after the methane gas M is separated in the accommodating portion 10 to the outside. The discharge port P3 communicates with the discharge pipe 12, and when the reciprocating moving portion 11 moves from the second position to the first position, the valve (described later) is opened and the deposit T2 is discharged to the outside. To do. The discharge pipe 12 discharges the sediment T2 onto the seabed away from the mining machine 2, for example.

The reciprocating moving portion 11 is housed in the accommodating portion 10. The reciprocating moving portion 11 can reciprocate inside the accommodating portion 10. The reciprocating moving portion 11 in this reference example is a so-called piston, and is driven via the piston rod 11b. By reciprocating the reciprocating moving portion 11, the volume of the separation space B can be reciprocally changed.

The drive unit 8 reciprocates the reciprocating moving unit 11 described above. More specifically, the drive unit 8 generates rotational energy for rotating the crankshaft 13 to which the piston rod 11b is linked. The drive unit 8 in this reference example is an underwater electric motor. The drive unit 8 is not limited to the electric motor, and an internal combustion engine may be used. Further, in FIG. 2, for convenience of illustration, the drive unit 8 is directly connected to the crankshaft 13, but the rotational energy of the drive unit 8 is usually transmitted to the crankshaft 13 via a speed reducer or the like.

The heating unit 9 heats the deposit introduced into the separation space B. The heating unit 9 includes a combustion gas supply unit 14 and an ignition unit 15.
The combustion gas supply unit 14 supplies a combustible gas containing a part of the methane gas M separated from the methane hydrate to the separation space B. The combustion gas supply unit 14 in this reference example includes a combustion gas supply pipe 16 and a methane gas branch pipe 17.

The combustion gas supply pipe 16 supplies, for example, a flammable carrier gas to the separation space B. The combustion gas supply pipe 16 in this reference example supplies oxygen to the separation space B as a flammable carrier gas. Further, the combustion gas supply pipe 16 in this reference example illustrates the case where the carrier gas is supplied from the collection mother ship 6.

The methane gas branch pipe 17 joins a part of the methane gas before being picked up by the riser pipe 5 with the carrier gas flowing through the combustion gas supply pipe 16. That is, the combustion gas in this reference example is a gas in which oxygen, which is a carrier gas, and methane gas M are mixed.

The ignition unit 15 ignites the combustion gas supplied to the separation space B by the combustion gas supply unit 14. As the ignition unit 15, for example, a spark plug can be used. The ignition of the combustion gas by the ignition unit 15 is not limited to the ignition in the separation space B. For example, a flame generated in a space different from the separation space B is introduced into the separation space B to ignite the combustion gas. You may let it.

The riser pipe 5 is a pipe that connects the above-mentioned separation device main body 7 and the collection mother ship 6. The riser pipe 5 in this reference example collects the methane gas separated by the plurality of separation device main bodies 7 and then pumps it by the compressor 18.

The collection mother ship 6 includes a tank T for temporarily storing the methane gas collected by the riser pipe 5. Further, the collection mother ship 6 also has equipment (not shown) for generating carrier gas to be supplied to the combustion gas supply pipe 16 described above. Further, the collection mother ship 6 may be provided with a liquefaction facility for liquefying the recovered methane gas. The methane gas stored in the collection mother ship 6 is transferred to, for example, a transport ship (not shown) and transported to a facility on land or the like.

The gas hydrate recovery system 1 of this reference example has the above-described configuration. Next, the operation of the separation / recovery device 4 described above will be described with reference to the drawings.
FIG. 3 is a diagram showing an introduction step of the separation / recovery device in the reference example of the present invention. FIG. 4 is a diagram showing a decompression step of the separation / recovery device in the reference example of the present invention. FIG. 5 is a diagram showing a recovery process of the separation / recovery device in the reference example of the present invention. FIG. 6 is a diagram showing a discharge process of the separation / recovery device in the reference example of the present invention. In addition, in FIGS. 3 to 6, the above-mentioned ignition unit 15 is omitted for convenience of illustration.

First, the drive unit 8 starts the reciprocating movement of the reciprocating moving unit 11. Then, the introduction process is performed. That is, in the separation / recovery device 4, the valve V1 of the introduction port P1 is opened when the reciprocating moving portion 11 is arranged at the first position shown in FIG. As a result, the deposit T1 containing methane hydrate is introduced into the separation space B in the accommodating portion 10. Here, the first position of the reciprocating moving portion 11 described above may be the top dead center of the reciprocating moving portion 11, but any position near the stroke end of the reciprocating moving portion 11 on the side where the volume of the separation space B becomes smaller. It may be a position. The valve V3 of the discharge port P3 may be slightly opened in order to smoothly introduce the deposit T1 into the separation space B.

Next, in the separation / recovery device 4, when the reciprocating moving unit 11 passes the top dead center and starts moving toward the bottom dead center, in other words, the reciprocating moving unit 11 moves from the first position to the second position. Once started, perform the separation process. That is, as shown in FIG. 4, the valves V1 and V3 are closed. As a result, the volume of the closed separation space B increases, and the separation space B is depressurized. Then, due to this decompression, the pressure of methane hydrate deviates from the stable region, and the methane gas M and water are separated from the methane hydrate. Here, in the separation step, the reciprocating moving unit 11 is slowly moved over time so that the pressure of the methane hydrate is maintained for a predetermined time in a state where the pressure of the methane hydrate is out of the stable region.

At this time, in this reference example, the methane hydrate is heated by the heating unit 9. That is, the combustion gas is supplied from the introduction port P1 together with the deposit T1 to the separation space B, and the combustion gas is ignited to heat the methane hydrate. This heating makes it easier for the temperature of the methane hydrate to deviate from the stable region, and makes it easier for the methane gas M and water to separate from the methane hydrate.

After that, in the separation / recovery device 4, the recovery step shown in FIG. 5 is performed. That is, when the reciprocating moving unit 11 reaches the second position, the collection port P2 is opened. The methane gas M separated inside the separation space B has a smaller specific gravity than the sediment T2 containing earth and sand and seawater and the separated water, and the volume is increased by the separation. Therefore, it is natural from this open recovery port P2. Is discharged to and supplied to the riser tube 5.

Then, when the recovery step is completed, the reciprocating moving unit 11 starts moving toward the top dead center (or the first position) again, and the recovery port P2 is closed first. After that, the discharge process is performed. That is, as shown in FIG. 6, the valve V3 of the discharge port P3 is opened, the deposit T2 is compressed by the reciprocating moving portion 11, and the deposit T2 is pushed out from the discharge port P3 to the discharge pipe 12. The deposit T2 extruded into the discharge pipe 12 gradually moves toward the end opening of the discharge pipe 12 by repeating each of the above steps, and is discharged from this end opening to the seabed or the like. ..

Therefore, according to the above-mentioned reference example, the deposit T1 containing methane hydrate can be introduced into the separation space B via the introduction port P1. Then, by moving the reciprocating moving portion 11 from the first position to the second position in this state, the separation space B can be depressurized. Further, this depressurization can separate the methane gas M from the methane hydrate.

Further, the reciprocating moving unit 11 moves to the second position, the recovery port P2 is opened, and the methane gas M separated from the methane hydrate can be recovered via the recovery port P2. Further, after the gas is recovered from the recovery port P2, the reciprocating moving portion 11 is moved from the second position to the first position, so that the deposit T2 remaining in the separation space B can be discharged from the discharge port P3.

As a result, the methane gas M can be separated efficiently by decompression as compared with the case where the methane gas M is separated from the methane hydrate mainly by heating. Further, since the pressure is reduced by the reciprocating movement of the reciprocating moving unit 11, the separation space B can be easily and surely reduced even on the deep sea bottom.

Further, by providing the heating unit 9, both decompression and heating of methane hydrate can be performed. As a result, methane gas M can be efficiently separated from methane hydrate.

Further, the combustion gas supplied to the separation space B can be ignited to efficiently heat the methane hydrate. Further, a part of the methane gas M separated from the methane hydrate can be heated as a fuel. Therefore, as compared with the case where the fuel for heating is supplied from the outside of the collection mother ship 6 or the like, the fuel supply from the outside can be suppressed, so that energy saving can be achieved.

Further, the methane gas M can be separated from the mined methane hydrate, and the separated methane gas M can be moved to the unloading mother ship 6 at sea via the riser pipe 5 and recovered. As a result, it is not necessary to raise the deposit T1 onto the collection mother ship 6, and the efficiency of gas recovery can be improved.

(Modified example of reference example)
Next, a modification of the reference example of the present invention will be described with reference to the drawings. Note that the modified example of this reference example differs from the above-mentioned reference example only in that the drive unit 8 is an internal combustion engine and that it is provided with a heat exchanger for preheating. Therefore, the same parts as those of the above-mentioned reference example will be described with the same reference numerals, and duplicate description will be omitted.

FIG. 7 is a schematic configuration diagram corresponding to FIG. 2 in a modified example of the reference example of the present invention. As shown in FIG. 7, the separation and recovery device 4B of the gas hydrate recovery system 1B in the modified example of the reference example of the present invention includes the separation device main body 7, the drive unit 8B, the heating unit 9, and the preheating unit (heat). Exchange unit) 20 and.

The drive unit 8B generates rotational energy for driving the reciprocating moving unit 11, similarly to the drive unit 8 of the reference example described above. The drive unit 8B in this modification is an internal combustion engine, and is capable of transmitting rotational energy to the crankshaft 13 described above via a transmission mechanism D such as a clutch or a speed reducer. As the internal combustion engine, for example, a reciprocating engine can be used. Further, the drive unit 8B is a gas engine that can be driven by using methane gas as fuel.

In the drive unit 8B, a part of the methane gas separated by the separation device main body 7 is supplied as fuel through the branch pipe 19. An exhaust pipe 21 for supplying exhaust gas to the preheating unit 20 is connected to an exhaust port (not shown) of the drive unit 8B.

The preheating section 20 preheats the deposit containing methane hydrate transferred by the transfer pipe 3. More specifically, the temperature of the methane hydrate contained in the sediment is heated so as not to deviate from the stable region. In other words, this heating does not separate methane gas from methane hydrate. The preheating unit 20 in this reference example uses the exhaust gas of the driving unit 8B as a heat source. The preheating unit 20 exchanges heat between the deposit containing methane hydrate and the exhaust gas.

Therefore, according to the modification of the reference example described above, the exhaust heat of the drive unit 8B can be recovered to heat the methane hydrate. Therefore, when the methane gas M is separated from the methane hydrate in the separation device main body 7, it can be separated more efficiently than the above-mentioned reference example.

Further, since the drive unit 8B can be driven by using the methane gas M separated by the separation device main body 7 as fuel, the fuel and electric power can be transmitted as compared with the case where the fuel and electric power are supplied from the sea lift mother ship 6 and the like. It is possible to reduce the equipment and energy required for salary.

In the modified example of the reference example, the case where the preheating unit 20 utilizes the exhaust heat of the driving unit 8B has been described as an example, but the heat medium may be supplied from another heat source. For example, the cooling water of the electric motor may be supplied to the preheating unit 20. Further, the fuel of the drive unit 8B is not limited to the methane gas M separated by the separation device main body 7. Further, the drive unit 8B is not limited to the gas engine.

(Embodiment)
Next, the separation recovery device and the gas hydrate recovery system according to the embodiment of the present invention will be described with reference to the drawings.
FIG. 8 is a configuration diagram showing a schematic configuration of a gas hydrate recovery system according to an embodiment of the present invention.
In this embodiment, a gas hydrate recovery system that recovers gas from methane hydrate as a gas hydrate will be described as an example. Further, in this embodiment, a case where methane hydrate existing on the deep sea bottom (for example, a water depth of about 1000 m) is excavated and collected together with earth and sand will be described. The methane hydrate to be collected may be either a sand layer type or a surface layer type.

As shown in FIG. 8, the gas hydrate recovery system 100 of this embodiment includes a mining machine 102, a transfer pipe 103, a separation recovery device 104, a riser pipe (lifting pipe) 105, and a collecting mother ship 106. , Is mainly provided.
The mining machine 102 crushes and inhales the sediment containing methane hydrate deposited on the seabed. Further, the mining machine 102 crushes the sucked sediment and supplies the crushed sediment to the separation / recovery device 104 via the transfer pipe 3.

The transfer pipe 103 is a pipe for transferring the fluid F1 containing the sediment containing the gas hydrate mined and crushed by the mining machine 102 and the seawater to the separation / recovery device 104. The transfer pipe 103 has an inner diameter capable of smoothly transferring the fluid F1 containing sediments, and has a pressure resistance performance sufficient for use on the seabed. Here, a pump or the like for pumping the sediment may be provided at the inlet of the transfer pipe 103, but the pump of the transfer pipe 3 can be omitted if the self-sufficiency action of the separation / recovery device 104 can be sufficiently obtained. ..

The separation / recovery device 104 separates methane gas from methane hydrate contained in the sediment transferred through the transfer pipe 103. Further, the separation / recovery device 104 discharges the sediment T2 containing the sediment and the seawater, which are the deposits from which the methane gas is separated, to the outside, respectively. Further, the separation / recovery device 104 pumps the separated methane gas through the riser pipe 105.

FIG. 9 is a schematic configuration diagram of a separation / recovery device according to an embodiment of the present invention.
As shown in FIG. 9, the separation / recovery device 104 in this embodiment includes a separation device main body 107 and a drive 108.
The separation device main body 107 includes a separation pipe 109, an inducer 110, a discharge pipe 111, a pumping unit 112, and a recovery pipe 113.

In the separation pipe 109, a deposit containing methane hydrate and a fluid F1 containing seawater are introduced via the transfer pipe 103 described above. The separation tube 109 accommodates the inducer 110 and the pumping section 112. The inducer 110 and the pumping unit 112 are arranged side by side in the order of the axis O direction of the separation pipe 109 and from the side closer to the transfer pipe 103. As a result, the fluid F1 introduced into the separation pipe 109 is first sucked into the inducer 110. Further, the separation pipe 109 has a slit portion S between the inducer 110 and the pumping portion 112. The slit portion S is provided with a plurality of narrow slits, and while allowing the methane gas M to pass through the pumping portion 112, it prevents earth and sand from flowing into the pumping portion 112. Although the slit portion S has been described as an example, a structure other than the slit portion S, such as a net-like member, may be adopted as long as it has a structure for preventing the inflow of earth and sand.

The inducer 110 rotates around the axis O of the separation pipe 109 to cause separation in the flow of the fluid F1 to separate the methane gas M from the methane hydrate. The inducer 110 is rotated at high speed by the drive unit 108. The inducer 110 includes wings 114 that project radially outward from the outer peripheral surface of the boss 121.

FIG. 10 is a developed view of the blades of the inducer according to the embodiment of the present invention as viewed from the outside in the radial direction. In FIG. 10, for convenience of explanation, the blade shape is shown in a simplified manner.
As shown in FIG. 10, a plurality of blades 114 are provided and are arranged at intervals in the axial direction O direction of the inducer 110, and are arranged equidistantly from each other in the circumferential direction of the inducer 110. When the inducer 110 is rotated in the circumferential direction A, the fluid F1 flowing from the upstream side in the axis O direction enters toward the blade 114.

A large angle of attack θ is set on the wings 114 of the inducer 110. Therefore, in the blade 114, the front edge separation of the fluid F1 is induced, and the fluid F1 in the vicinity of the front edge 114a of the blade 114 is separated. In other words, the blade 114 is formed at an angle that causes the fluid F1 to separate near its front edge and is sufficiently depressurized to separate the methane gas M. The angle of attack θ at which a sufficient decompression is obtained to separate the methane gas M can be obtained by simulation or the like based on various parameters such as the rotation speed of the inducer 110 and the shape of the blade set in advance. it can.

As shown in FIG. 9, the discharge pipe 111 is connected to the separation pipe 109 on the radial outer side of the inducer 110. The discharge pipe 111 discharges the fluid F1 that has moved outward in the radial direction due to centrifugation by the rotation of the inducer 110 to the outside such as the seabed. Here, the centrifugation by the inducer 110 moves the earth and sand and seawater contained in the fluid F1 radially outward near the inner wall of the separation pipe 109. On the other hand, since earth and sand and seawater move to the radial outside near the inner wall of the separation pipe 109, the methane gas M separated from the methane hydrate by the above-mentioned peeling moves to the radial inside of the separation pipe 109. , Is introduced into the pumping unit 112.

The pumping section 112 is provided on the downstream side of the inducer 110 in the separation tube 109. The pumping unit 112 in this embodiment shares a rotating shaft 122 with the inducer 110, and is rotationally driven by the driving unit 108. The pumping unit 112 illustrated in this embodiment is a compressor provided with a plurality of stages of impellers I1 to I3, and rotates around the axis O to compress the methane gas M separated from the methane hydrate. It is assumed that the methane gas M contains a small amount of seawater, and a wet gas compressor or a multiphase flow pump can be used as the pumping unit 112.

The recovery pipe 113 is connected to the separation pipe 109 on the downstream side of the pumping unit 112 to recover the compressed methane gas M. In other words, the recovery pipe 113 sends the compressed methane gas M toward the riser pipe 105. The compressed methane gas M is sent to the unloading mother ship 106 via the riser pipe 105.

The drive unit 108 rotates the inducer 110 and the pumping unit 112 around the axis O via the rotation shaft 122, respectively. In this embodiment, the case where an underwater electric motor is used as the drive unit 108 is illustrated, but an internal combustion engine or the like may be used.

Therefore, according to the separation recovery device and the gas hydrate recovery system of the above-described embodiment, the methane hydrate contained in the fluid F1 is depressurized by causing the flow of the fluid F1 to be separated by the inducer 110. Therefore, the methane gas M can be separated from the methane hydrate.

Further, by centrifugation by the inducer 110, sediments and seawater having a relatively large specific gravity move outward in the radial direction of the inducer 110, while methane gas M having a relatively small specific gravity moves to the outside of the inducer 110 in diameter. Move inward in the direction. Then, the centrifugally separated sediment T2, such as earth and sand and seawater, is discharged to the outside from the discharge pipe 111 on the outer side in the radial direction of the inducer 110.
Further, the methane gas M separated from the methane hydrate is sent to the pumping unit 112. Then, it is pumped by the pumping unit 112 and sent to, for example, a unloading mother ship 106 at sea via the recovery pipe 113.

As a result, the methane gas M can be separated efficiently by decompression as compared with the case where the methane gas M is separated from the methane hydrate mainly by heating. Further, since the methane hydrate is depressurized by utilizing the separation of the fluid F1 due to the rotation of the inducer 110, the methane hydrate can be depressurized easily and surely even on the deep sea bottom.

Further, unlike the embodiment, it is not necessary to supply oxygen and only electric power is required, so that the configuration can be suppressed from becoming complicated.

(Modified example of embodiment)
Next, a modification of the embodiment of the present invention will be described with reference to the drawings. It should be noted that the modified example of this embodiment is different from the above-described embodiment only in that it includes a heating unit. Therefore, FIG. 8 will be incorporated, and the same parts as those in the above-described embodiment will be described with the same reference numerals. Further, the duplicate description of the same part as that of the embodiment will be omitted.

FIG. 11 is a schematic configuration diagram of a separation / recovery device according to a modified example of the embodiment of the present invention.
As shown in FIG. 8, the separation / recovery device 104B of the gas hydrate recovery system 100B in the modified example of this embodiment separates the methane gas M from the methane hydrate contained in the sediment transferred via the transfer pipe 103. Let me. Further, the separation / recovery device 104B discharges the sediment and seawater from which the methane gas M has been separated to the outside, respectively. Further, the separation / recovery device 104B pumps the separated methane gas M through the riser pipe 105.
Then, as shown in FIG. 11, the separation / recovery device 104B includes a separation device main body portion 107B, a drive unit 108B, and a heating unit 120.

The separation device main body 107B includes a separation pipe 109, an inducer 110B, a discharge pipe 111, a pumping unit 112, and a recovery pipe 113. In FIG. 11, for convenience of illustration, the pumping section 112 and the recovery pipe 113 are omitted.

The inducer 110B rotates around the axis O to cause separation in the flow of the fluid F1 to separate the methane gas M from the methane hydrate. The inducer 110B is rotated at high speed by the drive unit 108B. The inducer 110B includes a wing 114 that protrudes radially outward from the outer peripheral surface of the boss 121. A plurality of wings 114 are provided and are arranged at intervals in the axis O direction of the inducer 110B, and are arranged equidistantly from each other in the circumferential direction of the inducer 110B.

The boss 121 is connected to the drive unit 108B via the rotation shaft 122.
The rotation shaft 122 rotates around the axis O to transmit the rotational energy output from the drive unit 108B to the boss 121.

The drive unit 108B rotates the inducer 110B and the pumping unit 112 (not shown) about the axis O, respectively. In the modified example of this embodiment, an underwater electric motor is used as the drive unit 108B.

The heating unit 120 can heat the fluid F1 introduced into the separation pipe 109. The heating unit 120 in this embodiment includes a first heating circuit 123, a second heating circuit 124, and a heat insulating material D1, respectively. The heating unit 120 may include only one of the first heating circuit 123 and the second heating circuit 124.

The first heating circuit 123 transfers the heat of the rotor 108Ba of the drive unit 108B to the boss 121 via the rotating shaft 122. The transferred heat raises the temperature of the boss 121, and the temperature rise of the boss 121 heats the fluid F1 in contact with the inducer 110B. In this embodiment, the first heating circuit 123 circulates the heat medium between the drive unit 108B and the boss 121. Specifically, the first heating circuit 123 includes a plurality of first flow paths 125 passing through a side close to the outer peripheral surface of the rotating shaft 122, and a second flow path 126 passing through a side close to the radial center of the rotating shaft 122. The heat medium is circulated by.

The second flow path 126 is connected to the plurality of first flow paths 125 so as to branch inside the rotor 108Ba of the drive unit 108B.
A plurality of first flow paths 125 are connected to the second flow path 126 so as to join inside the boss 121 of the inducer 110B.

According to the first heating circuit 123, first, the heat medium of the second flow path 126 heated by the heat generated by the rotor 108Ba expands in the rotor 108Ba and flows into the first flow path 125, respectively. After that, the heat medium reaches the inside of the boss 121 via the first flow path 125. Then, heat is exchanged between the heat medium and the fluid F1 to cool the heat medium. As a result, the heat medium is thermally contracted and flows from the first flow path 125 into the second flow path 126. Then, the heat medium reaches the inside of the rotor 108Ba through the second flow path 126, and the heating and cooling of the heat medium described above are repeated.

The second heating circuit 124 transfers the heat of the stator 108Bb of the drive unit 108B to the fluid F1. The second heating circuit 124 includes a circulation pipe 127, a first heat exchanger 128, a second heat exchanger 129, and a pump 130.
The circulation pipe 127 forms a flow path through which the heat medium flows. Further, the circulation pipe 127 forms a circulation flow path for circulating the heat medium between the drive unit 108B and the separation pipe 109 in the vicinity of the inducer 110B. A pump 130 is provided in the middle of the separation pipe 109, and a case where a heat medium is circulated by the output of the pump 130 is illustrated.

The first heat exchanger 128 exchanges heat between the stator 108Bb and the heat medium. That is, the heat medium is heated by the stator 108Bb. This heated heat medium is sent to the second heat exchanger 129 via the circulation pipe 127.

The second heat exchanger 129 exchanges heat between the outer wall of the separation pipe 109 at the position where the inducer 110B is arranged in the axis O direction and the heat medium. That is, the heat of the heat medium is transferred to the separation tube 109 by the second heat exchanger 129. This heat is transferred to the fluid F1 via the separation pipe 109, and the fluid F1 in the vicinity of the inducer 110B is heated.
Here, the heat medium used in the first heating circuit 123 and the second heating circuit 124 described above can also be referred to as a cooling liquid that cools the rotor 108Ba and the stator 108Bb of the drive unit 108B, respectively. The heat medium is not limited to a liquid, but may be a gas.

The heat insulating material D1 is heat-insulated so that heat energy does not escape from the second heating circuit 124 to the outside. The heat insulating material D1 mainly covers the drive unit 108B, the second heating circuit 124, and the separation tube 109.

Therefore, according to the modified example of the embodiment, the methane hydrate can be heated by the inducer 110B by effectively utilizing the exhaust heat of the drive unit 108B. As a result, in addition to the depressurization of the fluid F1 by the inducer 110B, the heating of the fluid F1 can be performed in parallel, so that the methane gas can be separated from the methane hydrate even more efficiently.

The present invention is not limited to the configuration of the above-described embodiment, and the design can be changed without departing from the gist thereof.
For example, in the reference example, a case where methane hydrate is heated using methane gas M separated from methane hydrate as fuel has been described. However, fuel for heating methane hydrate may be separately supplied from the outside such as the collection mother ship 106.

Further, in the reference example, the case where the methane hydrate is heated by the heating unit 9 has been described, but the heating of the methane hydrate by the heating unit 9 may be performed as appropriate and may be omitted.

Further, in the reference example, a case where a so-called piston type separation device main body 7 for reciprocating the reciprocating moving portion 11 in the accommodating portion 10 is used has been described. However, the separation device main body 7 is not limited to the piston type. It suffices if the internal volume can be easily increased. For example, a diaphragm type separator main body 7 using a diaphragm may be used.

Further, in the reference example, the case where the compressor 18 is provided in the riser pipe 5 has been described, but the configuration is not limited to the configuration in which the separated methane gas M is collected by using the compressor 18. For example, it may be collected without using the compressor 18.
Further, the number of installations of the separation device main body 7 is not limited to the three described in the reference example. Only one separating device main body 7 may be provided, or four or more may be provided.

Further, in the embodiment, the case where the pumping unit 112 is provided with three centrifugal stages by an impeller is illustrated, but the number of centrifugal stages is not limited to three. For example, it may have one stage or four or more stages.

Further, as in another aspect of the embodiment shown in FIG. 12, the speed increaser 131 may be provided in the middle of the rotating shaft 122 between the inducer 110 and the pumping unit 112. With this speed increaser 131, the rotation speed of the inducer 110 can be made higher than the rotation speed of the pumping unit 112. As the speed increaser 131, for example, a planetary gear-shaped in-line type can be used.

Further, in the modified example of the embodiment, the case where the first heating circuit 123 circulates the heat medium without using any power has been described. However, the first heating circuit 123 may be provided with a power source such as an actuator that circulates the heat medium. Further, in the modified example of the embodiment, the case where the second heating circuit 124 circulates the heat medium by using the pump 130 has been described. However, the present invention is not limited to this configuration, and the heat medium of the second heating circuit 124 may be circulated by a method other than using the pump 130, for example.

Further, in the modified example of the embodiment, the case where the fluid F1 is heated by the exhaust heat of the drive unit 108B has been described. However, the heat source for heating the fluid F1 is not limited to the drive unit 108B.

Further, in the modified example of the above-described embodiment, the case where the inducer 110B, the pumping unit 112, and the driving unit 108B are arranged side by side in the axis O direction has been described. However, the arrangement of the inducer 110B, the pumping unit 112, and the driving unit 108B is not limited to this arrangement. For example, the inducer 110B, the drive unit 108B, and the pumping unit 112 may be arranged in this order. By arranging in this way, the distance between the inducer 110B and the drive unit 108B can be shortened. As a result, the temperature drop of the heat medium can be suppressed, and the exhaust heat of the drive unit 108B can be efficiently transferred to the fluid F1.
Further, when the inducer 110B, the driving unit 108B, and the pumping unit 112 are arranged in this order, a speed reducer may be provided between the driving unit 108B and the pumping unit 112. By doing so, the rotation speed of the pumping unit 112 can be made lower than the rotation speed of the drive unit 108B. As a result, the speed of the drive unit 108B can be increased, so that the drive unit 108B can be miniaturized by using, for example, a high-speed motor. As the speed reducer, for example, a planetary gear-shaped in-line type can be used.

1 Gas hydrate recovery system 2 Mining machine 3 Transfer pipe 4 Separation recovery device 5 Riser pipe 6 Lifting mother ship 7 Separation device main body 8 Drive unit 9 Heating unit 10 Storage unit 10a Inner peripheral surface 11 Reciprocating movement unit 11a End surface 11b Piston rod 12 Discharge pipe 13 Crank shaft 14 Combustion gas supply part 15 Ignition part 16 Combustion gas supply pipe 17 Methane gas branch pipe 18 Compressor 19 Branch pipe 20 Preheating part 21 Exhaust pipe 100, 100B Gas hydrate recovery system 102 Mining machine 103 Transfer pipe 104 Separation Recovery device 105 Riser tube 106 Lifting mother ship 107 Separator body 108, 108B Drive section 108Ba Rotor 108Bb Stator 109 Separation tube 110, 110B Inducer 111 Discharge tube 112 Pumping section 113 Recovery tube 114 Wing 120 Heating section 121 Boss 122 Rotating shaft 123 1st heating circuit 124 2nd heating circuit 125 1st flow path 126 2nd flow path 127 Circulation pipe 128 1st heat exchanger 129 2nd heat exchanger 130 Pump 131 Accelerator D Transmission mechanism D1, D2 Insulation material M methane gas P1 Introductory port P2 Recovery port P3 Discharge port T1, T2 Sediment

Claims (4)

Separation pipes into which sediments containing gas hydrate and fluids containing seawater are introduced,
An inducer, which is arranged in the separation pipe and rotates around the axis of the separation pipe to cause separation in the flow of the fluid and separate the gas from the gas hydrate.
At least the drive unit that rotates the inducer,
A discharge pipe connected to the separation pipe on the radial outer side of the inducer and discharging the fluid to the outside by centrifugation by the inducer.
A pumping unit provided on the downstream side of the inducer in the separation pipe and pumping the gas by rotating around an axis.
A recovery pipe connected to the separation pipe on the downstream side of the pumping unit to recover the gas,
Separation and recovery device. The separation / recovery device according to claim 1, further comprising a heating unit capable of heating the fluid introduced into the separation tube. The heating part
The separation / recovery device according to claim 2, wherein the inducer is heated by the exhaust heat of the drive unit. The separation / recovery device according to any one of claims 1 to 3.
A mining device for mining the gas hydrate and
A transfer pipe that transfers the gas hydrate mined by the mining device to the separation and recovery device, and
A collection pipe that collects the gas recovered by the separation and recovery device, and
Gas hydrate recovery system equipped with.

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