JP4620440B2 - Gas hydrate generating apparatus and generating method - Google Patents

Description

  The present invention comprises a raw material gas supply means for supplying a raw material gas to the upper space portion in the reaction vessel, and a spray-type water supply means for supplying water by spraying the upper space portion in the reaction vessel. The present invention relates to a gas hydrate generating apparatus and a generating method for generating a gas hydrate by bringing the raw material gas into contact with the sprayed water under the temperature and pressure conditions.

  In gas hydrate, gas molecules such as hydrocarbons such as methane, ethane, propane, and butane, which are natural gas components, and carbon dioxide are taken into the interior of the three-dimensional structure formed by combining water molecules. It is a general term for clathrate hydrates (hydrates) formed in this way. In other words, gas hydrate is an ice-like solid substance composed of source gas molecules and water molecules, and is a kind of stable inclusion compound in which source gas molecules are included inside a three-dimensional cage structure formed by water molecules. It is. This gas hydrate has a relatively large gas storage capacity, and has characteristic properties such as large generation / decomposition energy and selectivity of hydrated gas. For example, transportation and storage of natural gas, etc. Various applications such as means, heat storage systems, actuators, and separation and recovery of specific component gases are possible, and research is actively conducted.

  Gas hydrate is usually generated under high pressure and low temperature conditions. The following methods are well known as generation methods. By spraying water cooled from the top of the reaction vessel filled with the raw material gas at a high pressure, when the water drops fall in the raw material gas, gas hydrate is generated on the surface of the water droplets. A so-called “bubbling method” or the like in which gas hydrate is generated on the bubble surface when the gas bubbles of the source gas rise in the water by introducing (bubbling) the gas as bubbles in the water.

  As an example of the prior art of an apparatus for generating this gas hydrate, there is an apparatus described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-327980). Since the gas hydrate produced by contacting the raw material gas and water in the reaction vessel has a specific gravity smaller than that of water, it floats on the water surface in the reaction vessel to form a gas hydrate layer. By continuing the contact reaction, the gas hydrate gradually accumulates on the water surface. This gas hydrate tends to grow and become a lump by gradually accumulating on the water surface. When the gas hydrate is agglomerated, the fluidity of the gas hydrate is reduced, and it becomes difficult to flow out from the outlet and to flow out of the reaction tube and out of the reaction vessel.

Therefore, a scraping blade is provided on the water surface portion in the reaction vessel, and the scraping blade is rotated to agitate the gas hydrate floating on the water surface to keep the fluidity, while scraping to the center side of the reaction vessel. The gas hydrate slurry is caused to flow in through the take-out pipe through the take-out port arranged at the center of the reaction vessel, and then taken out to the outside.
Here, the scraping blade is disposed such that the base end is located on the water surface and the lower end is immersed below the water surface. That is, the scraping blade rotates in direct contact with the gas hydrate floating on the water surface, and scrapes the gas hydrate toward the center of the reaction vessel.

JP 2003-327980 A

  Since the conventional gas hydrate generator has a structure in which the scraping blade rotates in direct contact with the gas hydrate floating on the water surface, the gas hydrate adheres and accumulates on the surface of the scraping blade, There was a problem that smooth squeezing could not be performed, the induction discharge of the gas hydrate slurry to the take-out pipe became unstable, and finally it was difficult to take out the gas hydrate slurry out of the reaction vessel.

  The objective of this invention is providing the production | generation apparatus of the gas hydrate which can stabilize taking-out of the gas hydrate slurry out of the reaction vessel with time.

  In order to achieve the above object, the first aspect of the present invention includes a reaction vessel, a raw material gas supply means for supplying a raw material gas to the upper space in the reaction vessel, and the upper space in the reaction vessel. A gas hydrate generation device that includes a spray-type water supply means that sprays and supplies water, and generates gas hydrate by bringing the raw material gas into contact with the sprayed water under predetermined temperature and pressure conditions. A gas hydrate which is located below the water surface in the reaction vessel, generates a swirling flow in the water in the reaction vessel by the rotation of the rotating blade, and floats on the water surface by the centrifugal force of the swirling flow The gas hydrate slurry collected by the swirling flow from the swirling flow generating means that collects the swirling flow at the central portion of the swirling flow, and the extraction port disposed near the water surface and near the central portion of the reaction vessel. Inflow Characterized in that it comprises a means extracting withdrawing slurry from the reaction vessel, the.

According to the present invention, the swirling flow generating means whose entire rotating blade is located below the water surface in the reaction vessel generates a swirling flow in the water in the reaction vessel by the rotation of the rotating blade, and the centrifugal force of the swirling flow generates The gas hydrate floating on the water surface is collected at the center of the swirling flow, and flows into the extraction port of the extraction means to be extracted out of the reaction vessel. Therefore, since the rotor blade is not in contact with the gas hydrate, there is no problem of gas hydrate adhesion to the blade surface as in the prior art, and a swirl flow can be stably generated over time.
Thereby, the extraction of the gas hydrate out of the reaction vessel can be stably continued. Furthermore, since the gas hydrate having a specific gravity smaller than that of water is collected in the center by the action of the centrifugal force of the swirling flow, the concentration of the gas hydrate slurry can be easily concentrated.

  Further, a second aspect of the present invention is the first aspect, wherein the swirl flow generating means includes two or more rotor blades arranged at equal intervals in the circumferential direction near the inner wall of the reaction vessel, A rotary blade is fixed to the lower end, and includes a support rod that extends vertically from below the water surface to the water surface, and a connecting portion that connects each support rod to the rotation shaft on the water surface.

  According to the present invention, in addition to the effect based on the first aspect, the support rod for fixing the rotor blade to the lower end locally agitates the peripheral portion of the gas hydrate layer on the water surface. Therefore, an effect of assisting the collecting action of the gas hydrate to the center by the centrifugal force of the swirling flow is obtained.

  According to a third aspect of the present invention, in the first aspect, the extraction unit includes an extraction pipe extending vertically downward from the extraction port, and the swirl flow generation unit includes the rotary blade The extraction tube is configured to rotate about the rotation center.

  According to the present invention, the extraction means includes an extraction pipe extending vertically downward from the extraction port, and the swirl flow generation means is configured such that the rotary blade rotates about the extraction pipe as a rotation center. Has been. Therefore, in addition to the effect based on the first aspect, there is no object that disturbs the swirling flow between the rotor blade and the water surface, so that the stability of the swirling flow is increased and the uniformity of the centrifugal force based on the swirling flow is increased. And the concentration of the gas hydrate slurry can be concentrated with high accuracy.

Further, the fourth aspect of the present invention is that a source gas is supplied to the upper space part in the reaction vessel, water is sprayed and supplied to the upper space part in the reaction vessel, and a predetermined temperature and pressure condition is satisfied. A gas hydrate generating method for generating gas hydrate by bringing the raw material gas and the sprayed water into contact with each other, wherein the water in the reaction vessel is converted by rotation of a rotary blade located below the water surface in the reaction vessel. The gas hydrate that generates a swirling flow and floats on the water surface is collected in the central portion by the centrifugal force of the swirling flow, and from the outlet located near the water surface and near the central portion of the reaction vessel, The gas hydrate slurry collected by the swirling flow is extracted from the reaction vessel.
According to the present invention, the same effect as that of the first aspect can be obtained.

  According to the present invention, since the rotor blade is not in contact with the gas hydrate, there is no problem of gas hydrate adhesion to the blade surface as in the prior art, and a swirling flow can be stably generated over time. . Therefore, the extraction of the gas hydrate out of the reaction vessel can be stably continued. Furthermore, since the gas hydrate having a specific gravity smaller than that of water is collected in the center by the action of the centrifugal force of the swirling flow, the concentration of the gas hydrate slurry can be easily concentrated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Example 1]
FIG. 1 is a schematic configuration diagram showing an embodiment of a natural gas hydrate generating apparatus according to the present invention. A gas nozzle 7 constituting a raw material gas supply means for supplying a raw material gas 5 made of natural gas to the upper space 3 in the reaction vessel 1 is provided at the upper part of the reaction vessel 1. The gas nozzle 7 communicates with a gas supply source (not shown) and injects the raw material gas 5 into the reaction vessel 1 with a controlled injection amount. In addition, a spray nozzle 11 that constitutes a spray-type water supply unit that sprays water 9 onto the upper space 3 in the reaction container 1 is provided at another part of the upper part of the reaction container 1.

  The inside of the reaction vessel 1 is adjusted to a predetermined temperature and pressure by a known method. In this embodiment, the temperature is 3 ° C. and the pressure is 5 MPa. Under this temperature and pressure, the raw material gas 5 and the sprayed water 9 come into contact with each other to generate a gas hydrate 13. Since the amount of gas hydrate produced is as small as about 1 to 5% by weight with respect to the amount of raw material water used for the reaction, the raw material gas 5 and water 9 are circulated and fed into the reaction vessel 1. The generated gas hydrate is accumulated on the water surface to increase its amount and concentrate. In general, the concentration of the gas hydrate slurry is concentrated to 10 to 30% by weight, preferably about 20% by weight in consideration of the ease of subsequent extraction from the reaction vessel 1 and the ability of the further concentration apparatus. I am doing so.

In the apparatus of FIG. 1, a circulating supply structure of water 9 is shown. That is, a takeout port 15 for water 90 as a liquid is provided near the bottom of the vessel below the water surface of the reaction vessel 1, and the takeout port 15 and the spray nozzle 11 are connected via a circulation line 17. The circulation line 17 is provided with a circulation pump 19 and a heat exchanger 21. The circulation pump 19 sends water 90 as a liquid from the take-out port 15 toward the spray nozzle 11 and generates a spray force of the spray nozzle 11. The heat exchanger 21 serves to lower the water temperature to the temperature condition of water as a raw material for generating gas hydrate (3 ° C. in the present embodiment).
The gas hydrate is generated by a hydration reaction by contact between water and the raw material gas, and at this time, heat of generation is generated. In order to remove this generated heat (98 kcal / kg in the case of methane), a known cooling device 23 is provided.

  A swirling flow generating device 25 is provided for generating a swirling flow in the water 90 as the liquid in the reaction vessel 1. The swirl flow generator 25 is located entirely under the water surface in the reaction vessel 1 in the rotor blades 27, 27,... A swirling flow is generated, and the gas hydrate 13 floating on the water surface by the centrifugal force of the swirling flow is collected in the central portion 29 of the swirling flow.

  In this embodiment, four rotary blades 27, 27,..., Which are close to the inner wall 31 of the reaction vessel 1 and arranged at equal intervals in the circumferential direction, and the rotary blades 27, 27,. Four support rods 33, 33,... Vertically extending from below to the water surface, and four connecting portions 37, 37 that connect each support rod 33, 33,. The swirl flow generating device 25 is configured. In FIG. 1, the code | symbol 39 shows the drive device which rotates the rotating shaft 35. In FIG.

  Here, the specific settings such as the shape and size of the rotor blades 27, 27,... And the rotational speed of the rotor blades 27, 27,... Are relative and are not determined uniformly. In short, the gas hydrate 13 floating on the water surface is set so that it can be collected in the central portion 29 of the swirling flow by utilizing the difference in specific gravity with water by the centrifugal force of the swirling flow to be generated. Ideally, it is desirable to have a swirl flow in which there is almost no undulation on the water surface, there is almost no turbulent flow below the water surface, and a uniform concave surface having a V-shaped side view with the most concave central portion of the water surface is formed. However, the role of the swirling flow can be fulfilled substantially without doing so.

  Furthermore, an extraction device 40 for extracting the slurry of the gas hydrate 13 collected as described above to the outside of the reaction vessel 1 is provided. In this embodiment, the extraction device 40 has an extraction port 41 located near the water surface and near the center of the reaction vessel 1, and an extraction pipe 43 extending vertically downward from the extraction port 41, An extraction pump 45 provided in the extraction pipe 43 is provided. The slurry of the gas hydrate 13 flows into the extraction pipe 41 and is extracted to the outside of the reaction vessel 1 through the extraction pipe 43.

Next, the operation of the first embodiment will be described.
In this embodiment, the rotating blades 27, 27,... Of the swirling flow generator 25 located entirely below the water surface in the reaction vessel 1 are turned into the water 90 in the reaction vessel 1 by the rotation of the rotating blades 27, 27,. A swirling flow is generated, and the gas hydrate 13 floating on the water surface is collected at the center of the swirling flow by the centrifugal force of the swirling flow, and flows into the extraction port 41 of the extraction device 40 to be extracted out of the reaction vessel 1. It is configured. Therefore, since the rotor blades 27, 27,... Are not in contact with the gas hydrate 13, there is no problem of gas hydrate adhesion to the blade surface as in the prior art, and a swirling flow is stably generated over time. be able to.
Thereby, the extraction of the gas hydrate 13 out of the reaction vessel 1 ”can be stably continued. Furthermore, since the gas hydrate 13 having a specific gravity smaller than that of water is collected in the central portion by the action of the centrifugal force of the swirling flow, the concentration of the gas hydrate slurry can be easily concentrated.

  Further, the support rods 33, 33,... That fix the rotary blades 27, 27,... At the lower end locally agitate the periphery of the gas hydrate 13 layer on the water surface. The action of collecting the gas hydrate 13 at the center by the centrifugal force of the swirling flow is assisted.

[Example 2]
FIG. 2 is a schematic diagram showing another embodiment of the natural gas hydrate generating apparatus according to the present invention. In this embodiment, the swirling flow generating device 25 is disposed at the center of the bottom of the reaction vessel 1, and includes a rotary blade 28 as a main component, a rotary shaft 36 of the rotary blade 28, and the rotary shaft 36. And a driving device 38 that rotates. Further, the extraction device 40 is arranged so that the extraction pipe 44 is bent in an L shape and penetrates the side surface of the reaction vessel 1 by arranging the swirling flow generating device 25 at the center of the bottom of the reaction vessel 1. It is arranged. The spray nozzle 11 is provided in the upper center portion of the reaction vessel 1. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the same portions, and the description thereof is omitted.

  According to the second embodiment, since the extraction pipe 44 bent in an L shape exists between the rotary blade 28 and the water surface, the swirling flow is easily disturbed by that amount, but at a practically effective level, The gas hydrate 13 can be collected at the center by the action of the centrifugal force of the swirling flow, and the concentration of the gas hydrate slurry can be concentrated.

[Example 3]
FIG. 3 is a schematic configuration diagram showing still another embodiment of the natural gas hydrate generator according to the present invention. In the present embodiment, the swirling flow generating device 25 is configured such that the rotary blade 26 rotates around the extraction pipe 43 extending vertically downward from the extraction port 41. The shaft portion 42 of the rotary blade 26 is formed so as to be able to rotate through the bottom of the reaction vessel 1, and rotates using a motor 46 provided outside the reaction vessel 1 as a driving force source. A known technique is applied to the liquid seal in the through portion. The rotary blade 26 is not limited to the illustrated example, and may be driven by a pressure-resistant underwater motor (not shown) provided in the reaction vessel. Since other configurations are the same as those of the first embodiment shown in FIG. 1 or the second embodiment shown in FIG. 2, the same portions are denoted by the same reference numerals, and the description thereof is omitted.

  According to the third embodiment, the extraction device 40 includes an extraction pipe 43 that extends vertically downward from the extraction port 41, and the swirling flow generator 25 has a rotating blade 26 that rotates about the extraction pipe 43 as a rotation center. Is configured to do. That is, since there is nothing that disturbs the swirling flow between the rotor blades 26 and the water surface, the stability of the swirling flow is increased compared to the first and second embodiments, and the uniformity of the centrifugal force based on the swirling flow is increased. This further increases the concentration of the gas hydrate slurry with high accuracy.

  The present invention comprises a raw material gas supply means for supplying a raw material gas to the upper space portion in the reaction vessel, and a spray-type water supply means for supplying water by spraying the upper space portion in the reaction vessel. It can be used for a gas hydrate generating device and a generating method for generating gas hydrate by bringing the raw material gas into contact with the sprayed water under the temperature and pressure conditions.

It is a schematic block diagram which shows one Example of the natural gas hydrate production | generation apparatus which concerns on this invention. It is a schematic block diagram which shows the other Example of the natural gas hydrate production | generation apparatus which concerns on this invention. It is a schematic block diagram which shows the further another Example of the natural gas hydrate production | generation apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container 3 Upper space part 5 Raw material gas 9 Sprayed water 13 Gas hydrate 21 Heat exchanger 25 Swirling flow generators 26-28 Rotary blade 27 Rotary blade 29 Center part of rotational flow 33 Support rod 40 Extraction device 41 Extraction port 42 Shaft part 43 Extraction pipe 46 Motor 90 Water as liquid

Claims (4)

A reaction vessel, source gas supply means for supplying a source gas to the upper space in the reaction vessel, and spray water supply means for supplying water by spraying the upper space in the reaction vessel. A gas hydrate generating device for generating gas hydrate by bringing the raw material gas into contact with the sprayed water under a predetermined temperature and pressure condition,
The entire rotor blade is located below the water surface in the reaction vessel, and the rotating blade generates a swirling flow in the water in the reaction vessel, and the swirling force causes the gas hydrate floating on the water surface to swirl. A swirl flow generating means for collecting at the center of the flow;
An extraction means for extracting the slurry out of the reaction vessel by flowing the slurry of the gas hydrate collected by the swirling flow from an extraction port disposed near the water surface and near the center of the reaction vessel; equipped with a,
The swirling flow generating means includes two or more rotor blades arranged at equal intervals in the circumferential direction near the inner wall of the reaction vessel, and each rotor blade is fixed to the lower end, and vertically extends from below the water surface to the water surface. A gas hydrate generating apparatus comprising: an extended support bar; and a connecting part that connects each support bar to a rotating shaft on the water surface . A reaction vessel, source gas supply means for supplying a source gas to the upper space in the reaction vessel, and spray water supply means for supplying water by spraying the upper space in the reaction vessel. A gas hydrate generating device for generating gas hydrate by bringing the raw material gas into contact with the sprayed water under a predetermined temperature and pressure condition,
The entire rotor blade is located below the water surface in the reaction vessel, and the rotating blade generates a swirling flow in the water in the reaction vessel, and the swirling force causes the gas hydrate floating on the water surface to swirl. A swirl flow generating means for collecting at the center of the flow;
An extraction means for extracting the slurry from the reaction vessel by flowing the slurry of the gas hydrate collected by the swirling flow from an extraction port disposed near the water surface and near the center of the reaction vessel; equipped with a,
The swirl flow generating means is configured such that the rotary shaft of the rotary blade can rotate through the center of the bottom of the reaction vessel, and the entire rotary shaft is located below the water surface.
The extraction means includes an extraction tube that extends from the extraction port and is disposed so as to pass through the side surface of the reaction vessel through between the rotary blade and the water surface. Gas hydrate generator. A raw material gas is supplied to the upper space part in the reaction vessel, and water is sprayed and supplied to the upper space part in the reaction vessel. Under the predetermined temperature and pressure conditions, the raw material gas and the sprayed water are supplied. A gas hydrate production method for producing gas hydrate by contacting
A swirling flow is generated in the water in the reaction vessel by the rotation of two or more rotor blades located under the water surface in the reaction vessel and near the inner wall of the reaction vessel and arranged at equal intervals in the circumferential direction. The gas hydrate layer floating on the water surface is formed by a centrifugal force of the swirl flow and a support rod that fixes each rotor blade to the lower end and extends vertically from below the water surface to the water surface. The gas hydrate slurry collected by the swirling flow is collected out of the reaction vessel from an extraction port arranged near the water surface and near the central portion of the reaction vessel. A method for producing a gas hydrate comprising extracting. A raw material gas is supplied to the upper space part in the reaction vessel, and water is sprayed and supplied to the upper space part in the reaction vessel. Under the predetermined temperature and pressure conditions, the raw material gas and the sprayed water are supplied. A gas hydrate production method for producing gas hydrate by contacting
By rotation of a rotary blade located below the water surface in the reaction vessel , which is supported by a rotating shaft configured to be rotatable through the center of the bottom of the reaction vessel and to be entirely located below the water surface. A swirling flow is generated in the water in the reaction vessel, and the gas hydrate floating on the water surface is collected in the central portion by the centrifugal force of the swirling flow, and is disposed near the water surface and near the central portion of the reaction vessel. The gas hydrate slurry collected by the swirling flow is caused to flow from the outlet, and extends from the outlet and passes between the rotor blade and the water surface and penetrates the side surface of the reaction vessel. A gas hydrate production method characterized in that the gas hydrate is drawn out of the reaction vessel by means of an extraction pipe arranged to do so .

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