JP5771762B1 - Sampling method of submerged self-injecting methane gas - Google Patents

Abstract

An object of the present invention is to provide a water bottom self-injecting methane gas collection method capable of collecting gas from a bottom methane plume at low cost. A cylindrical container having an inverted cup shape with a lower end opened and a closed upper end is used, and a collection container having a gas collection cavity as the inside of the trunk is used. A propulsion device for moving in the water, and connecting the tip of the collection gas outlet pipe to this collection vessel and connecting the tip, and adjusting the buoyancy of the collection vessel with the buoyancy adjustment device, The methane gas is operated and submerged in a position covering the methane gas outlet at the bottom of the water, and the methane gas ejected into the collection vessel is led out to the ship through the pipe for collecting the collected gas. [Selection] Figure 2

Description

  The present invention relates to a method for collecting water bottom self-injecting methane gas that collects methane gas that is self-injecting from the bottom of the water.

In recent years, methane hydrate (
Development of methane gas extraction technology from Methane hydrate ).

  Methane hydrate freezes with water when methane gas confined in water molecules meets conditions at various depths in the surface of the seabed and in the ground, and it exists as ice blocks. Methane gas can be separated and extracted from the ice block by breaking the conditions, that is, the temperature and pressure conditions for maintaining stabilization.

  However, mining methane gas that destabilizes methane hydrates that are 1000 m to 300 m deep and destabilize methane hydrate that exists at a depth of 1000 m in the ground surface or in the ground is an alternative to other fossil fuels. To achieve this, the mining cost is too high and it is difficult to realize.

  On the other hand, it is known that in the methane hydrate reserve, methane gas erupts from the surface of the bottom of the water, and ascending columns of methane gas bubbles (methane plume) reaching a height of several hundred meters are generated.

  This methane plume is known to erupt from the top of a special topography of the seafloor surface, that is, a so-called outer ring-shaped ridge around a circular depression with a diameter of several hundreds of meters.

  The methane plume self-injecting from the bottom of the water gradually melts into the water while rising in the water, and the bubbles disappear before reaching the water surface.

  There has been developed a method for collecting self-injecting methane gas from the bottom of the methane plume that is collected near the bottom of the water, led to a ship on the surface of water through a pipe, and injected into a gas tank (for example, Patent Document 1). In this technology, a rigid pipe is suspended from a work boat on the surface of the water while being connected in sequence, and an umbrella-shaped trap is fixed to the tip of the pipe, and this is positioned on the methane gas jet outlet. This technology captures the rising methane gas, guides it through a pipe onto a work boat, and pressurizes it into a predetermined pressurized tank.

JP 2014-201875 A

  In the conventional gas collection technology from the methane plume described above, it is necessary to hang a rigid steel pipe from the work boat on the surface of the water to the location where the methane gas is ejected from the bottom of the water. Since it is at a depth of 1000 m or more, it is difficult to carry out the work for bringing the collector to a predetermined position.

  In recent years, there are technologies to stop a ship at a certain position on the bottom of the water, drill thousands of meters on the seabed of thousands of meters, and unmanned submersibles to work on the bottom of thousands of meters. However, these are a collection of extremely high-precision and high-performance technologies, and the cost of using them is enormous. When used for gas extraction from the methane plume, the collected methane gas is more than the existing fossil fuel. There is a problem that it becomes expensive and unprofitable.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a method for collecting water bottom self-injecting methane gas capable of collecting gas from a water bottom methane plume at low cost.

The feature of the invention described in claim 1 for solving the above-described conventional problem is that methane gas is self-injected through an inverted cup-shaped collection container in which a collection gas extraction pipe is communicated and the lower side is opened. In the method of collecting water bottom self-injected methane gas, which is installed in an arrangement covering the bottom methane gas outlet, and the methane gas ejected into the collection container is led out to the ship through the collection gas derivation pipe, the collection container is cylindrical. The barrel has an inverted cup shape with the lower end opened and the upper end closed, and the barrel has a gas collection cavity, and the collection container has an internal air volume. A buoyancy adjustment device having a buoyancy adjustment cavity that adjusts buoyancy by changing, and a propulsion device that moves the collection container in water are provided in an arrangement fixed to the collection container , For extracting the collected gas A flexible material is used as the pipe, and the tip of the pipe for extracting the collection gas is connected to the upper part of the gas collection space in the inner cylinder to be connected to the collection container. While adjusting the buoyancy by pouring and draining into the buoyancy adjustment cavity, the propulsion device is operated to sink to a position covering the methane gas self-injection location on the bottom of the water, and the self- injected methane gas is taken into the gas collection space and collected The purpose is to lead out to the ship through the gas outlet pipe.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the collection container has a double cylindrical body portion including a steel outer cylinder and an inner cylinder. The inside of the cylinder is used as the gas collection space, and the space between the outer cylinder and the inner cylinder is used as a buoyancy adjustment cavity that constitutes the buoyancy adjustment device, and the collection container is poured and drained into the cavity. The purpose is to adjust the buoyancy.

  According to a third aspect of the present invention, in addition to the structure of the first or second aspect, the gas whose lower side is released into the collection container by closing the upper end of the trunk of the collection container with a ceiling plate. A collection space is formed, the ceiling plate is formed in an inverted funnel shape, and a collected gas outlet pipe is communicated with the upper end portion thereof.

  According to a fourth aspect of the present invention, in addition to the configuration according to any one of the first to third aspects, the propulsion device includes a horizontal movement screw having a rotation axis oriented in a horizontal direction, and a rotation axis moved up and down. And having a vertically moving screw directed in the direction.

  According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, the propulsion device includes a vertical rudder that regulates a horizontal movement direction and a horizontal rudder that regulates a vertical movement direction. The purpose is to control the direction of movement during settling.

According to the present invention, as described in claim 1, an inverted cup-shaped collection container, which is connected to a collection gas outlet pipe and is opened on the lower side, is installed in a layout that covers a bottom methane gas outlet from which methane gas is self-injecting. In the method of collecting water bottom self-injecting methane gas, the methane gas ejected into the collection vessel is led out to the ship through the collection gas derivation pipe, and the collection vessel has a cylindrical trunk, An inverted cup shape with the lower end opened and the upper end closed is formed, the inside of the barrel portion is used as a gas collection cavity, and the buoyancy is adjusted by changing the internal air volume in the collection container. A buoyancy adjustment device having a buoyancy adjustment cavity and a propulsion device for moving the collection container in water are provided in a fixed arrangement with respect to the collection container, and the collection gas outlet pipe is flexible. Use materials with The tip of the collection gas outlet pipe communicates with the upper part of the gas collection space in the inner cylinder and is connected to the collection container, and the collection container is buoyant by pouring and draining into the buoyancy adjustment cavity. The propulsion device is operated while being adjusted to sink to a position covering the methane gas self-injection site on the bottom of the water, and the self- injected methane gas is taken into the gas collection space and led out to the ship through the collection gas extraction pipe. Because of this, the collection vessel is settled while moving vertically and horizontally by its own propulsion device separately from the support vessel, so that the collector is fixed under the conventional steel pipe and lowered to a predetermined position. In comparison, even in locations where there is a tidal current, it is possible to sink only the collection container at a predetermined position without requiring sophisticated ship maneuvering techniques.

  Moreover, since the collection container to be used only needs to cover the spout where the methane bloom at the bottom of the water is generated, the size can be set to an appropriate size convenient for the setting operation, and the steel inverted cup is used. The cost of equipment can be reduced, and a wide range of gas outlets can be easily handled by increasing the number of collection containers used. Cost disadvantages compared to fuel mining are eliminated.

  According to a second aspect of the present invention, the collection container has a double cylindrical body made of a steel outer cylinder and an inner cylinder, and the inside of the inner cylinder serves as the gas collection space. The space between the outer cylinder and the inner cylinder is a buoyancy adjustment cavity that constitutes the buoyancy adjustment device, and the buoyancy of the collection container is adjusted by pouring and draining into the cavity. The conventional steel shell caisson technology can be used, and there is no technical difficulty in manufacturing the collection container, and a collection container with a highly reliable buoyancy adjustment function can be easily produced.

  According to the present invention, the upper end of the body portion of the collection container is closed by a ceiling plate to form the gas collection space whose lower side is opened in the collection container, and the ceiling plate is turned upside down. By forming the funnel shape and connecting the collection gas outlet pipe to the upper end of the funnel, the gas rising in the collection container can be efficiently led out.

  The present invention uses the propulsion device according to claim 4 having a horizontal movement screw with the rotation axis oriented in the horizontal direction and a vertical movement screw with the rotation axis oriented in the vertical direction. The horizontal movement can be performed independently, the settling speed can be increased, hovering is facilitated, and the set-up work at a predetermined position can be efficiently performed.

  According to a fifth aspect of the present invention, the propulsion device includes a vertical rudder that regulates the horizontal movement direction and a horizontal rudder that regulates the vertical movement direction, and controls the movement direction when the collection container is settling. Therefore, movement in water can be easily and accurately performed.

It is the side view which shows the outline of collection container installation in the method of this invention, and shows the state in the middle of collection container installation. It is a side view which shows the state after collection container setting same as the above. It is a longitudinal cross-sectional view which shows an example of a collection container same as the above. It is the same top view. The other example of the propulsion apparatus used for the method of this invention is shown, (a) (b) is the partial front view of the state which changed the angle of the screw shaft.

  Embodiments of the present invention will be described with reference to the drawings of the embodiments.

  As shown in FIG. 1, the method for collecting submarine self-injected methane gas according to the present invention uses a sonar or a submarine submersible craft to explore the methane plume a ejected on the seabed, and provides an outlet b suitable for gas collection. Select and place a sound wave transmitter (ultrasonic sonar) near it.

  In addition, the methane plume a becomes a bubble in the vicinity of the spout b on the bottom of the water and rises in a columnar shape. As the gas rises, the gas is absorbed by the water and the bubble becomes small, and reaches about 300 m from the bottom. Everything dissolves in the water and the bubbles disappear. Therefore, it is most efficient to collect methane gas from the methane plume at the bottom of the water from which the gas is jetted before the gas dissolves in the water.

  In this method, a steel collection container A having an inverted cup shape with a diameter of about 10 m to several tens of m and a height of the same size as the diameter is used. For example, they are manufactured in a land caisson production yard equipped with ships, caisson manufacturing docks, and launching equipment, and are towed on the sea using their buoyancy. Depending on the size of the collection container A, it may be mounted on a work boat and moved, suspended on the water surface in the vicinity of the settling area, and floated.

  This collection container A is controlled from above the support ship B and is laid down so as to cover the upper periphery of the jet outlet b of the desired methane plume a. It should be noted that the post-sinking posture may be any posture that allows the jetted gas to be collected in the collection container A, and even if there is unevenness or inclination on the bottom surface of the water, it will be installed with an inclination along this. That's fine.

  The collection of the collection container A is performed with the target being a sound wave from a sound wave transmitting device that is installed in advance as a set position. Sedimentation is performed by a buoyancy adjusting function provided in the collection container A itself and horizontal and vertical propulsion devices. At the time of settling, the tip of the collecting gas outlet pipe C for sending the collected gas to the water is fixed in a state where it is connected to the upper end of the internal space of the collecting container A, and the settling support pipe C for sinking is supported. While being drawn out from the top of the ship B, by the function of the collection container A itself, the ship B is horizontally moved to a predetermined position while being submerged.

  After settling, the gas spouted in the collection vessel A is led out to the settling support vessel B through the collection gas derivation pipe C and stored in a predetermined pressure vessel in a pressurized state. Whenever a predetermined amount is reached, it is transferred to a gas carrier and transferred to a land storage.

  Next, the specific example of the collection container A which collects the methane plume a is demonstrated.

  This collection container A has a cylindrical hollow body 2 and is formed in an inverted cup shape whose lower end is opened and whose upper end is closed by a ceiling plate 3. The trunk | drum 2 is carrying out the taper cylinder shape whose diameter of a lower end side is wider than an upper end side.

  The size of the body part 2 depends on the size of the methane plume ejected from the bottom of the water, but considering the economics of manufacturing and substituting work, the diameter is several tens of meters, and the height is about the same as the diameter. Is preferred.

  The body 2 has a double wall structure composed of a steel plate outer cylinder 2a and an inner cylinder 2b, and a predetermined interval is maintained by interposing a spacer between the cylinders 2a and 2b. A buoyancy adjusting cavity 4 is formed between the double walls, and the buoyancy is adjusted by adjusting the volume of the internal cavity. The double wall structure also serves to reinforce water pressure.

  A plurality of buoyancy adjustment cavities 4 are provided in the upper half of the body 2 in the week direction, and the buoyancy of each of the buoyancy adjustment cavities 4, 4... Is adjusted individually. Thus, the posture of the entire collection container A is controlled.

  Water injection into the buoyancy adjusting cavity 4 reduces buoyancy by injecting and exhausting water by opening the bottom water injection valve 20 and opening the upper exhaust valve 21. Further, the buoyancy is increased by closing the exhaust valve 21, opening the bottom pouring / draining valve 20, injecting air from the air cylinder 22 filled with high-pressure air, and discharging water for the injected air volume.

  At the upper end of the body portion 2, a lattice-like top end reinforcement structure 6 made of a steel-made girder is integrated so as to close the inside of the top end, and a ceiling plate 3 is fixed to the lower side thereof, and the ceiling plate 3 closes the upper end of the body 2 in an airtight manner. The inner cylinder 2 b whose upper end is closed by the ceiling plate 3 is a gas collection cavity 8.

  As shown in FIG. 3, the ceiling plate 3 is formed in an inverted funnel shape having a raised central portion, and an exhaust port 7 is formed in the central portion, and a collected gas outlet pipe C is connected to the exhaust port 7. ing.

  The collected gas lead-out pipe C is embedded with a desired cable (umbilical cable, not shown) such as a power cord and a control cord. A signal for supplying and controlling these can be sent from the settling support vessel B. In addition, you may make it perform control of said various transmission equipment by a radio | wireless apparatus.

  The collection container A is equipped with a propulsion device for settling and horizontal movement. As this propulsion device, a pair of horizontal movement screws 11 and 11 and vertical movement screws 12 and 12 are used, and each is driven by an electric motor (not shown).

  The horizontal movement screws 11, 11 are attached to symmetrical positions on the outer peripheral surface of the body portion 2 with the rotation axis directed in the horizontal direction, and have a rudder 13 at the rear thereof. The propulsion direction can be adjusted by converting the rudder angle into a necessary direction by a driver such as a pulse motor.

  Further, the rotational speed and forward / reverse rotation of the horizontal movement screws 11 and 11 can be controlled, and the direction of the entire collection container A can be changed by changing the rotation direction.

  The vertical movement screws 12 and 12 are located on the outer periphery of the trunk portion 2 and are located at positions shifted by 90 degrees in the trunk week direction with respect to the above-described horizontal movement screws 11 and 11, with the rotation axis directed in the vertical direction. It has a structure projecting outside the portion 2 and is driven by an electric motor. The vertical movement screws 12 and 12 can control the rotation speed and the forward / reverse rotation, and can adjust the sedimentation speed and the rising speed.

  A plurality of cameras with lights 14 are installed on the outer periphery of the lower portion of the trunk portion 2 and the bottom of the water can be monitored on the ship through these cameras.

  In this example, the power source of the equipment installed in the collection container A is supplied from the ship through the power cord along the collection gas outlet pipe C. However, a lithium battery is used as the power source. Each device may be operated by wireless control.

  The sedimentation operation of the collection container A is carried out by adjusting the buoyancy of the buoyancy adjustment cavity 4 to float on the water surface, and feeding the collection gas derivation pipe C from the settling support vessel B while in the buoyancy adjustment cavity 4. Settling by pouring water to reduce buoyancy.

  The position of the collection container A during the subsidence is confirmed by data from a depth gauge (not shown) attached to the collection container A and the sonar provided in the settling support ship B. Settling while controlling so as not to slip off. In addition, sedimentation is performed by adjusting buoyancy, and the sedimentation speed is controlled by the vertically moving screw 12. Further, the settling speed at the time of bottoming is reduced or hovered immediately before the bottoming, and the horizontal position is finely adjusted by the horizontal moving screw 11.

  These position adjustment operations are performed by operating various devices provided in the collection container A while visually checking the data from the underwater camera on the settling support ship B to set the data at a predetermined position.

  Although not shown in the figure, an unmanned submersible is used to support the sinking, and image information such as the sinking state and the state of the bottom of the water is sent to the sinking support ship B, and the work proceeds while visually observing this. May be.

  Furthermore, the movement to the final settling position is such that the gas enters the collection container A by lowering the collection container A near the bottom of the horizontal surface off the methane plume a, and the collected gas is discharged. It is preferable to prevent it from rising up to the ship through the pipe C and to move the collection container A horizontally on the methane plume a near the bottom of the water.

  By moving onto the methane plume a, the gas enters the collection container A, and the gas accumulates in the upper end of the collection container A. The upper end of the gas lead-out pipe C is opened, the water in the collected gas lead-out pipe C pushed up by the gas is discharged, and the gas discharged after the water discharge ends is stored in the storage tank on the settling support ship B To house.

In the above-described apparatus, two types of screws having horizontal and vertical thrusts are used as the propulsion device for controlling the settling position of the collection container A. In addition, as shown in FIG. Two propulsion devices that can be rotated 360 degrees about the axis 16 of the rotation axis about the horizontal axis 17 are installed at symmetrical positions of the collection container A, whereby the settling direction of the collection container A is set. You may make it control.

A Collection vessel B Sedimentation support ship C Pipe for extracting collected gas a Methane plume b Outlet 2 Body 2a Outer cylinder 2b Inner cylinder 3 Ceiling plate 4 Buoyancy adjustment cavity 6 Top end reinforcement structure 7 Exhaust outlet 8 Gas trap Cavity 11 Horizontally moving screw 12 Vertically moving screw 13 Rudder 14 Lighted camera 15 Screw 16 Axle 17 Horizontal shaft 20 Drain valve 21 Exhaust valve 22 Air cylinder

Claims (5)

The methane gas spouted into the collection container is installed in an upside-down cup-shaped collection container that is connected to the collection gas outlet pipe and is open on the lower side to cover the methane gas spout at the bottom of the methane gas. In the method of collecting the bottom self-injecting methane gas that is led out to the ship through the collected gas lead-out pipe,
The collection container has a cylindrical body part, the body part has an inverted cup shape in which the lower end is opened and the upper end is closed, and the inside of the body part is used as a gas collection cavity part,
In addition, the collection container includes a buoyancy adjustment device having a buoyancy adjustment cavity that adjusts buoyancy by changing an internal air volume, and a propulsion device that moves the collection container in water. , In preparation for an arrangement fixed to the collection container ,
A flexible material is used as the collection gas extraction pipe, and the tip of the collection gas extraction pipe is connected to the upper part of the gas collection space in the inner cylinder and connected to the collection container. And
While adjusting the buoyancy by pouring / draining the buoyancy adjustment cavity into the buoyancy adjustment cavity, the propulsion device is operated to sink the methane gas self-injection location on the bottom of the water, and the self- injected methane gas is submerged in the gas collection space. A method for collecting submerged self-injected methane gas, characterized in that it is introduced into a ship through a pipe for extracting and collecting collected gas. The collection container has a double cylindrical body made of a steel outer cylinder and an inner cylinder, and the inside of the inner cylinder serves as the gas collection space,
The space between the outer cylinder and the inner cylinder is a buoyancy adjustment cavity that constitutes the buoyancy adjustment device, and the buoyancy of the collection container is adjusted by pouring and draining into the cavity. How to collect self-injecting methane gas from the bottom.   By closing the upper end of the body portion of the collection container with a ceiling plate, the gas collection space opened on the lower side is formed in the collection vessel, the ceiling plate is formed in an inverted funnel shape, and the upper end portion thereof 3. The method for collecting submerged self-injected methane gas according to claim 1 or 2, wherein a pipe for extracting collected gas is communicated with the bottom gas.   The submarine self-injecting methane gas according to any one of claims 1 to 3, wherein the propulsion device includes a horizontal movement screw having a rotation axis oriented in a horizontal direction and a vertical movement screw having a rotation axis oriented in a vertical direction. Collection method. The bottom propellant methane gas according to claim 4, wherein the propulsion device includes a vertical rudder that regulates a horizontal movement direction and a horizontal rudder that regulates a vertical movement direction, and controls a movement direction when the collection container is settling. Collection method.

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