JP2001288125A - Apparatus for dehydrating gas hydrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas hydrate dehydration apparatus in which efficient continuous dehydration of the slurry-like gas hydrate is performed and the dehydrated product is took out. SOLUTION: A conveyer used for dehydration process 36 comprising a belt 35 wound and moved on a roller 34 is disposed. A plurality of dehydration mechanisms 37 for the slurry-like methane hydrate MH carried on the conveyer 36 are disposed at a specified distance in the transfer direction. Each dehydration mechanism 37 comprises a pair of dehydration drums 41 disposed on both front and back surfaces of the belt 35. The dehydration drums 41 and the belt 35 are made of stainless steel plates with mesh. The slurry-like methane hydrate MH is fed between the dehydration drums 41 nipped and the surface of the methane hydrate MH is pressed on the drums 41. Water contained in the slurry- like methane hydrate MH is thereby squeezed out from the surfaces of the dehydration drums 41 directly or through the belt 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas hydrate dehydrator for dehydrating adhering water contained in a slurry gas hydrate produced.

[0002]

2. Description of the Related Art At present, as a method of storing and transporting natural gas mainly composed of hydrocarbons such as methane, natural gas is collected from a gas field, cooled to a liquefaction temperature, and liquefied natural gas (LNG). It is a common practice to store and transport in a state where it is kept. However, for example, in the case of methane, which is a main component of liquefied natural gas, liquefaction requires cryogenic conditions such as -162 ° C. In order to store and transport while maintaining such conditions, a dedicated storage device is required. And dedicated transportation means such as an LNG ship. Since the production, maintenance and management of such devices and the like require extremely high costs, low-cost storage and transportation methods that are alternatives to the above methods have been intensively studied. As a result of these studies, a method has been discovered in which natural gas is hydrated to produce a gas hydrate in the solid state (hereinafter referred to as "gas hydrate") and stored and transported in the solid state. Particularly promising. This method does not require cryogenic conditions as in the case of handling LNG, and is relatively easy to handle because it is solid. For this reason, an existing refrigeration system or a slightly improved version of an existing container ship can be used as a storage device or a transportation means, and therefore, it is expected that the cost can be significantly reduced.

[0003] The gas hydrate is a kind of clathrate compound (clathrate compound). As shown in FIG. 6, a three-dimensional cage-type clathrate formed by a plurality of water molecules (H ₂ O) is used. A crystal structure in which molecules constituting each component of natural gas, that is, methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), etc. are contained in a lattice (clathrate) and are included. It is what makes. The intermolecular distance between the natural gas constituent molecules included in the clathrate is shorter than the intermolecular distance in the gas cylinder when natural gas is charged at a high pressure. This means that natural gas can produce tightly packed solids, for example, under conditions where methane hydrate can be stably present, ie at -30 ° C. and atmospheric pressure (1 kg / cm ² ), The volume can be reduced to about 1/190 compared to the state. As described above, gas hydrate can be obtained at a relatively easy temperature and temperature.
It can be manufactured under pressure conditions and can be stably stored.

In this method, natural gas after being received from a gas field is subjected to an acid gas removal step in which an acid gas such as carbon dioxide (CO ₂ ) or hydrogen sulfide (H ₂ S) is removed. It is stored in the gas storage part once under high pressure. This natural gas is then hydrated in a hydrate generation step to become gas hydrate. This gas hydrate is a slurry in which water is mixed, and in the subsequent dehydration step, mixed unreacted water is removed, and further adjusted to a predetermined temperature and pressure through a cooling step and a decompression step. In a state, it is sealed in a container such as a container and stored in a storage device. This gas hydrate may be stored directly in a cooled storage device. At the time of transportation, the above-mentioned container is loaded on a transportation means such as a container ship, or the formed and cooled gas hydrate is loaded on a refrigerated ship as it is to be transported to the destination. After landing at the destination, the gas hydrate is returned to a natural gas state through a hydrate decomposition step and sent to each supply point. Alternatively, they may be decomposed on a refrigerated ship to return to the state of natural gas and sent to each supply point.

[0005]

By the way, in the above-mentioned gas hydrate, it is necessary to satisfactorily remove the water adhering to the slurry-like gas hydrate in order to increase the transport efficiency. The dehydration of the adhering water attached to the hydrate has to be performed not only without decomposing the gas hydrate, but also has been desired to efficiently remove a large amount of the adhering water of the gas hydrate for dehydration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to a gas hydrate capable of efficiently dewatering a slurry gas hydrate supplied from a gas hydrate production reactor. The purpose is to provide a dehydrator.

[0007]

In order to achieve the above object, a gas hydrate dehydrator according to claim 1 is a gas hydrate for dehydrating a slurry gas hydrate supplied from a gas hydrate production reactor. A dewatering device, comprising a transfer means for transferring the slurry gas hydrate, and a dehydration means provided in the middle of the transfer of the slurry gas hydrate by the transfer means, wherein the dehydration means has water permeability. And having a cylindrical dehydrating drum that takes out water adhering to the slurry gas hydrate from the peripheral surface by being pressed against the slurry gas hydrate transferred by the transfer means while rolling. I have.

[0008] As described above, the slurry gas hydrate transferred by the transfer means is brought into pressure contact with the dewatering drum having water permeability while rolling, so that the slurry gas hydrate can be very easily removed from the peripheral surface of the dewatering drum. The gas hydrate can be dehydrated by removing the water adhering to the rate. In other words, it is possible to easily and efficiently remove the attached water from a large amount of slurry gas hydrate containing the attached water to perform dehydration, and at the time of dehydration, the gas hydrate is pressurized, so that the hydrate does not decompose. In addition, the effect that the attached water is hydrated is also exerted.

A gas hydrate dehydrator according to a second aspect is characterized in that, in the gas hydrate dehydrator according to the first aspect, the dehydration drum is subjected to mesh processing to impart water permeability. .

[0010] As described above, the slurry gas hydrate transferred by the transfer means is brought into pressure contact with the dewatering drum, which has been subjected to mesh processing on the peripheral surface and is provided with water permeability, while being rolled, thereby making it extremely easy. Further, the water adhering to the slurry-like gas hydrate is taken out from the mesh on the peripheral surface of the dehydration drum, and the gas hydrate can be dehydrated.

According to a third aspect of the present invention, there is provided the gas hydrate dehydrator according to the first or second aspect, wherein the dehydrating means is arranged along a direction in which the transfer means transfers the slurry gas hydrate. It is characterized in that a plurality are provided.

In other words, since a plurality of dehydrating means are provided along the direction in which the slurry gas hydrate is transported by the transporting means, the dehydrating drums of these dehydrating means provide
The dewatering process can be continuously performed from the transferred slurry gas hydrate, and the dewatering can be performed easily and very efficiently by removing the adhered water from a large amount of the slurry gas hydrate containing the adhered water.

According to a fourth aspect of the present invention, there is provided the gas hydrate dehydrator according to the third aspect, wherein the dehydrating means is arranged so that the dehydrating means moves rearward in a direction in which the slurry gas hydrate is transported by the transporting means. It is characterized in that the pressing force to the gas hydrate is increased in order.

That is, in the plurality of dehydrating means arranged along the transfer direction, the pressing force of the dehydration drum against the gas hydrate is gradually increased toward the rear in the transfer direction, so that the dehydration on the upstream side is performed. The attached water can be more reliably taken out from the slurry gas hydrate dehydrated by the means and dewatered, and the dehydration can be performed at a high dehydration rate.

According to a fifth aspect of the present invention, there is provided the gas hydrate dehydrator according to any one of the first to fourth aspects, wherein the dehydrating means includes a pair of the hydrates which are urged in an approaching direction. It is characterized by having a dehydrating drum and holding the slurry-like gas hydrate between these dewatering drums to take out water adhering to the slurry-like gas hydrate from the peripheral surface of each dehydrating drum.

That is, the transferred slurry gas hydrate is fed between a pair of dehydration drums, so that the gas hydrate is sandwiched between the pair of dehydration drums, and water adhering to the gas hydrate is discharged from each of the dehydration drums. It can be taken out and the dewatering efficiency can be further increased.

According to a sixth aspect of the present invention, in the gas hydrate dehydration apparatus according to the fifth aspect, the transfer means moves the dewatering belt having water permeability by using a roller, so that the dehydration belt is provided on the dehydration belt. A dewatering conveyor for transferring the slurry gas hydrate, the dewatering drums are provided on the front and back of the dewatering belt for transferring the slurry gas hydrate, and the dewatering drum holds the slurry gas hydrate together with the dewatering belt. It is characterized by.

As described above, since the transfer means is constituted by the dewatering conveyor for transferring the slurry gas hydrate by the dewatering belt having water permeability, the slurry is transferred during the transfer of the slurry gas hydrate by the dewatering belt. Water attached to the gas hydrate can be taken out of the dewatering belt, and the dewatering efficiency can be further improved.

A gas hydrate dehydrator according to a seventh aspect is characterized in that, in the gas hydrate dehydrator according to the sixth aspect, the dewatering belt is provided with water permeability by performing mesh processing. .

That is, since the transfer means is constituted by a dewatering conveyor for transferring the slurry-like gas hydrate by a dewatering belt which has been subjected to mesh processing and is provided with water permeability, the slurry-like gas hydrate is conveyed by the dewatering belt. During the transfer, the water adhering to the slurry gas hydrate can be taken out from the mesh of the dewatering belt, and the dewatering efficiency can be further improved.

The gas hydrate dehydrator according to claim 8 is the gas hydrate dehydrator according to claim 6 or 7, wherein the gas hydrate dehydrator is provided on the delivery side of the slurry gas hydrate to be transferred to the dehydration conveyor. A scraper for scraping gas hydrate adhering to the belt is provided along the surface.

As described above, the dehydrated gas hydrate adhering to the dehydration belt of the dehydration conveyor can be scraped by the scraper provided on the delivery side of the dehydration conveyor, and can be sent to the next step.

According to a ninth aspect of the present invention, in the gas hydrate dehydration apparatus according to any one of the first to eighth aspects, the gas hydrate dehydration apparatus adheres to the dehydration drum when the slurry hydrate is pressed against the gas hydrate slurry. A scraper for scraping the gas hydrate is provided along the peripheral surface.

That is, the gas hydrate adhering to the peripheral surface of the dewatering drum can be reliably scraped by the scraper provided along the peripheral surface of the dewatering drum and returned to the transfer means.

[0025]

Next, embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, an apparatus and a method for consistently producing methane hydrate using a gas hydrate forming substance as methane gas which is a main component of natural gas will be described. But not limited thereto, ethane, propane, butane, krypton, xenon, carbon dioxide and the like. As shown in FIGS. 6 (a) and 6 (b), the methane hydrate MH is provided in a basket in which water molecules W are arranged in a three-dimensional form (for example, dodecahedral or tetrahedral). Is a kind of clathrate compound (clathrate) containing, for example, produced based on the following reaction formula. Further, when the methane hydrate MH is decomposed, about 0.9 volume of methane hydrate and about 170 methane gas in a standard state are obtained. _{CH 4 + 5.75H 2 O → CH} 4 · 5.75H 2 O + Mizuwanetsu

FIG. 3 is a block diagram showing an embodiment of a gas hydrate producing apparatus in which the gas hydrate dehydrating apparatus of the present invention is incorporated. In FIG. 3, reference numeral 1 in FIG.
Is a closed gas hydrate generation reactor, in which a cooling coil 2 is inserted as a cooling means (temperature control means) in the gas hydrate generation reactor 1 of the pressure vessel. Thereby, the below-mentioned aqueous phase L in the gas hydrate generation reactor 1 can be cooled and maintained at, for example, about 1 ° C. within the gas hydrate generation temperature range (eg, 1 to 5 ° C.). Methane hydrate MH
When methane hydrate is generated, methane hydrate MH is not generated unless it is in a low-temperature and high-pressure state. Cooling is preferred. In the illustrated example, the cooling coil 2 is used as the cooling means, but is not limited to this. For example, the gas hydrate production reactor 1 may be surrounded by a cooling jacket, and the cooling jacket may be supplied with brine from a brine tank and circulated, or a radiator may be inserted into the gas hydrate production reactor 1, or These may be used in combination.

Reference numeral 3 denotes a water storage tank. When water is introduced from the water storage tank 3 into the gas hydrate generation reactor 1 through the pipe 4, the water storage tank 3 enters the gas hydrate generation reaction vessel 1. An aqueous phase L (liquid phase) can be formed. The pipe 4 is provided with a water supply pump 5 and a valve 6, and is controlled so that the liquid level S of the aqueous phase L is maintained at a constant level. In addition, the water storage tank 3, the pipe 4, and the water supply pump 5
The water supply means WS is constituted by the above.

On the lower side wall of the gas hydrate production reactor 1, a methane inlet 1a is provided. The methane inlet 1a has a gas storage unit 7 as a methane supply source.
And a methane gas (gas hydrate forming substance) is supplied through a pipe 8. The pipe 8 is provided with a normal valve 9 and a flow control valve 10. The degree of opening of the flow control valve 10 is controlled by a pressure gauge 11 that detects the pressure of a gas phase G (methane gas) described later in the gas hydrate generation reactor 1. Thereby, methane is replenished in the gas hydrate generation reaction vessel 1, and the pressure of the gas phase G is constantly increased to the gas hydrate generation pressure (4 in this example).
0 atm). A methane supply means (gas hydrate forming substance supply means) GS is constituted by the gas storage unit 7 and the pipe 8, and the pressure control means PC in the production reactor is controlled by the pressure gauge 11 and the flow rate control valve 10.
Is configured.

The methane (natural gas containing methane as a main component) supplied to the gas storage unit 7 is collected from a gas field 12 and then subjected to an acidic gas removing step 13 to remove acidic gases such as carbon dioxide and hydrogen sulfide. Is done. Thereafter, the temperature is reduced to a low temperature / high pressure via a compressor or the like, and sent to the gas storage unit 7 to be temporarily stored.

At the bottom of the gas hydrate production reactor 1, there is provided a water outlet 1b for extracting unreacted water, and the unreacted water extracted from the water outlet 1b is supercooled. Then, it is configured to be supplied again into the gas hydrate production reactor 1. More specifically, the water outlet 1b and the spray nozzle 14 provided at the top of the gas hydrate generation reactor 1 are connected by a pipe 15, and the pipe 15 has a valve 16, a water circulation pump 17, a heat exchanger, and the like. (Cooler) 18 and valve 19
Are sequentially arranged. The water extracted by the water circulation pump 17 is supercooled by the heat exchanger 18,
The gas is supplied from the spray nozzle 14 into the gas phase G (methane atmosphere) in the gas hydrate production reactor 1 in the form of a spray (see reference symbol SP).

Here, the supercooling means, as shown in FIG.
At least the temperature is lower than an arbitrary point D on the methane hydrate production equilibrium line C (in the direction of arrow X) or the pressure is higher (in the direction of arrow Y). In addition, the area above the generation equilibrium line C (the area shaded for convenience)
Is a hydrate generation region (under hydrate generation conditions). For reference, ethane, propane and butane formation equilibrium lines are also shown. As the heat exchanger (cooler) 18,
For example, a multi-tube heat exchanger having excellent heat conduction efficiency, a coil heat exchanger having a simple structure, and a plate heat exchanger having excellent heat conduction efficiency and easy maintenance can be used. In addition, the water circulation pump 17, the pipe 15, the heat exchanger 18,
Thus, a water subcooling circulation unit CW is configured.

Here, the spray nozzle 14 is shown in FIG.
As shown in (a), a gas hydrate generation reactor 1
Water particles SP having an outer diameter of several tens of μm on average (in principle, the smaller the particle diameter, the better) from the nozzle hole 14 a of the spray nozzle 14 toward the gas phase G. Gushing. As described above, the surface area per unit volume of water, that is, the contact area with the gas phase G is extremely increased by spraying water into the gas phase G in a spray form to form a large amount of water particles SP. Can be. As described above, when the unreacted water extracted from the bottom of the gas hydrate generation reactor 1 is sprayed in the gas hydrate generation reactor 1 by the spray nozzle 14,
It is important to prevent clogging of the spray nozzle 14 by foreign matter. Therefore, a filter 16a for collecting foreign matter such as gas hydrate is provided in the pipe 15,
It is preferable to reliably remove foreign matter from the extracted unreacted water. The spray means of FIG. 4B will be described later.

A liquid layer outlet 1c is provided near the liquid surface S of the aqueous phase L in the gas hydrate production reactor 1.
The liquid layer outlet 1c is connected to a gas hydrate dehydrator 30 described later by a pipe 20. The pipe 20 is provided with a valve 21, an extraction pump 22, and the like as necessary. With such a configuration, the relatively low-density methane hydrate layer MH floating on the liquid surface S is sucked by the extraction pump 22 from the liquid layer extraction port 1c, and
The methane hydrate and water are turned into a slurry, and are transferred to the subsequent process through the pipe 20. That is, the slurry-like methane hydrate (slurry gas hydrate) generated by the gas hydrate generation reactor can be easily supplied to the gas hydrate dehydrator 30 in the subsequent step by flowing the same together with excess water. It is.

Next, the configuration of the gas hydrate dehydrator 30 according to the present invention will be described in detail with reference to FIG. This gas hydrate dehydrator (hereinafter, dehydrator) 30
Is a device for dehydrating and extracting the slurry-like methane hydrate MH supplied from the gas hydrate production reactor 1 described above. The removal device main body 31 of the dehydration device 30 is a pressure vessel, and the inside is filled with gas.
In addition, the temperature and pressure are maintained so that the methane hydrate MH does not decompose. A supply port 32 is provided at an upper portion of the take-out apparatus main body 31, and methane hydrate MH in a slurry state is fed from a pipe 20 connected to the supply port 32 and supplied to a dehydration belt 35 described later. It is supposed to be. A continuous dehydrator 33 is provided in the take-out device main body 31 as a continuous dehydrating means.

The continuous dehydrator 33 includes a pair of rollers 34
A dewatering conveyor (transfer means) 36 around which an endless dewatering belt 35 is wound, and a belt portion of the dewatering conveyor 36 above the dewatering belt 35 are disposed at intervals along the longitudinal direction. Multiple dehydration mechanisms (dehydration means) 3
7, and the dehydration conveyor 36 transports the methane hydrate MH sent onto the dehydration belt 35 to the next step by rotating the roller 34 in the direction of the arrow in the figure. ing. As shown in FIG. 2, the dewatering mechanism 37 includes cylindrical dewatering drums 41 disposed on the front and back of the dewatering belt 35 and urged by a predetermined pressure in directions approaching each other. 41, the methane hydrate MH sent onto the dewatering belt 35
Are sent in with the movement of the dewatering belt 35.

The dewatering belt 3 constituting the dewatering conveyor 36
The dehydrating drum 41 constituting the dehydrating mechanism 5 and the dehydrating mechanism 37 are each made of stainless steel plate and provided with water permeability by mesh processing, and have a large number of holes of several μm. When the slurry-like methane hydrate MH on the dewatering belt 35 is fed between the dewatering drums 41 of the dewatering mechanism 37, the methane hydrate MH is compressed by the dewatering drum 41. That is, the dehydrating drum 4
1 is pressed against the slurry-like methane hydrate MH while rolling, and the water adhering to the methane hydrate MH flows from the peripheral surface of the upper dehydrating drum 41 to the inside thereof, and from the peripheral surface of the lower dehydrating drum 41. It is designed to be taken out via a dewatering belt 35. In addition, the dehydration mechanism 37 gradually moves toward the feed side of the methane hydrate MH,
The compressive force between the dewatering drums 41 is increased, whereby the pressing force of each dewatering drum 41 against the slurry-like methane hydrate MH is increased in the order toward the feed side.

The attached water taken out by the dewatering mechanism 37 is stored in the storage 31a below the take-out device main body 31 from the inside of the dewatering drum 41, and then sent out to a pipe 49 connected to the storage 31a. , This piping 4
9 by opening the drain valve 49a provided in
The gas is returned to the storage tank 3 through the pipe 49 and is reused in the gas hydrate generation reactor 1. The dehydrating mechanism 37 includes an upper dehydrating drum 41.
A scraper 42 is provided along the peripheral surface of the methane hydrate MH attached to the peripheral surface during the compression dehydration of the methane hydrate MH, and the methane hydrate MH is scraped off.
It is to be returned to the top.

Further, a scraper 43 is provided along the surface of the dewatering belt 35 on the downstream side that is the delivery side of the dehydrated methane hydrate MH, and the scraper 43 is provided with the dehydrated methane hydrate MH. Is scraped off from the dewatering belt 35 and transferred to the next step. Then, the methane hydrate MH dehydrated by the continuous dehydrator 33 is sent out to the next step, where it is cooled and cooled.
The pressure is reduced, and then molded into a predetermined shape and transported.

Next, the operation of the above-described gas hydrate manufacturing apparatus, that is, the manufacturing method will be described. The air in the gas hydrate generation reactor 1 is replaced with methane gas in advance, and then the water phase is introduced into the gas hydrate generation reactor 1 from the water storage tank 3 so that the liquid surface S is higher than the liquid layer outlet 1c. L is introduced. This aqueous phase L may contain a stabilizer if necessary. Next, the water phase L in the gas hydrate production reactor 1 is cooled to a predetermined temperature of, for example, about 1 ° C. by the cooling coil 2, and thereafter, the temperature is controlled so as to maintain this temperature.

When the temperature of the aqueous phase L is stabilized at a predetermined temperature, methane in the gas storage unit 7 is continuously introduced as bubbles K from the methane inlet 1a. As a result, at least part of methane is absorbed into the aqueous phase L from the gas-liquid interface of the bubbles K, and reacts with water to be converted into methane hydrate (hydration reaction).
The methane hydrate MH generated by the reaction floats in the aqueous phase L because the density is smaller than the density of water, and the liquid surface S
Form a layer on top. This methane hydrate layer MH
The liquid is extracted from the liquid layer extraction outlet 1 c by the extraction pump 22 and sent out to the gas hydrate dehydrator 30 through the pipe 20. At this time, the methane hydrate is recovered together with the water, so that it is in a slurry state. As the methane hydrate layer MH is extracted from the liquid layer extraction outlet 1c, the liquid level S of the aqueous phase L is lowered, so that new water is discharged from the water storage tank 3 so that the level of the liquid level S is kept constant. The water is supplied into the gas hydrate production reactor 1 via the water supply pump 5.

When methane hydrate MH is generated in the gas hydrate generation reactor 1, gas methane becomes solid methane hydrate MH, and the internal pressure decreases. On the other hand, in order to generate methane hydrate at high speed, the conditions in the gas hydrate generation reactor 1 must be set to a lower temperature and higher pressure. Therefore, in order to eliminate the pressure drop of the hydrate production vessel 1 due to the production of methane hydrate, the pressure in the gas hydrate production reactor 1 is continuously detected by the pressure gauge 11 and the flow rate is determined based on the pressure. The opening of the control valve 10 is continuously controlled. Thereby, the required amount of the raw material methane is replenished into the gas hydrate generation reactor 1, and the inside of the gas hydrate generation reactor 1 is maintained at a constant high pressure state, thereby achieving high-speed generation.

On the other hand, unreacted methane gas not absorbed in the aqueous phase L is released from the liquid surface S and accumulates as a gas phase G in the gas hydrate production reactor 1. Unreacted water is extracted from the bottom of the gas hydrate production reactor 1, supercooled by a heat exchanger 18, and then sprayed in the gas hydrate production reactor 1 by a spray nozzle 14. Thus, the gas hydrate generation reactor 1
A large amount of supercooled water particles SP is released into the methane gas filled therein, which greatly increases the contact area per unit volume of the water particles SP with methane and immediately causes a hydration reaction. Generated to speed. The generated hydrate falls to the liquid surface S and is collected in the same manner as described above. When methane hydrate MH is generated in the gas hydrate generation reactor 1, a large heat of hydration is generated. On the other hand, in order to generate methane hydrate MH at high speed, the conditions in the hydrate generation vessel 1 must be set to a lower temperature and higher pressure state. Therefore, discharging the supercooled water particles SP into the gas hydrate generation reactor 1 also effectively removes the heat of hydration.

When the gas hydrate production reactor 1 is large, the water at the bottom thereof may be in a supercooled state. Therefore, this water is taken out directly, that is, without cooling. It may be sprayed on the upper part of the gas hydrate production reactor 1 as it is.

In the above-described embodiment, the bubble K of methane rises in the aqueous phase L, so that the bubble interface can be always in contact with new water molecules without being covered with a high-viscosity reaction product. Is promoted. By continuing this operation in a stable state, high-concentration methane hydrate can be efficiently and continuously supplied to the dehydration cooling device 30.

If the particle diameter of the water particles SP ejected from the spray nozzle 14 is large, methane hydrate generated on the surface of the water particles impedes the supply of methane, so that the whole water particles SP may become methane hydrate. Can not.
Therefore, by spraying a gas together with water from the spray nozzle 14 to reduce the average particle diameter of the water particles SP to about 10 μm, it is possible to reduce the adhesion of methane hydrate as described above. Examples of the gas include an inert gas that does not react with water or a hydrate-forming substance. The number of spray nozzles 14 is not limited to one, but may be plural. Further, the average particle size of the water particles is 1
FIG. 5B shows another method for reducing the size to about 0 μm.
As shown in the figure, an ultrasonic vibration plate 90 is provided in the upper part of the gas hydrate generation reactor 1, and supercooled water is supplied from the pipe 15 on the ultrasonic vibration plate 90 to form a water film 91,
The water particles SP may be released from the water film 91 by ultrasonic vibration. In this case, the particle diameter of the water particles SP becomes more uniform, and no adverse effect is caused by the ejection of the gas.

In general, the reaction between methane and water proceeds at a pressure of 40 atm or more, for example, when the reaction temperature is 1 ° C. Therefore, the gas hydrate production reactor 1 requires a high-pressure vessel with a pressure resistance of at least 40 atm. When it is desired to carry out the reaction at a higher temperature and lower pressure, it is preferable to add a stabilizer to the aqueous phase L. Examples of stabilizers that can shift the hydration reaction of methane to higher temperature and lower pressure include aliphatic amines such as isobutylamine and isopropylamine; alicyclic ethers such as 1,3-dioxolan, tetrahydrofuran and furan. And cyclobutanone,
Alicyclic ketones such as cyclopentanone; aliphatic ketones such as acetone; Since all of these stabilizers have a hydrocarbon group and a polar group in the molecule, each polar group attracts a water molecule and the hydrocarbon group attracts a methane molecule, thereby reducing the intermolecular distance. It is thought to promote the hydration reaction. For example, by adding aliphatic amines, 10 ° C., 20 kg / cm ² G
At 10 ° C. and 10 kg / cm ² G or less depending on the addition of tetrahydrofuran. These stabilizers are used in an amount of 0.1 to 1000 g of pure water.
It is preferable to add within the range of 10 mol.

The reaction temperature depends on the above-mentioned relation of the production equilibrium.
It is better to be as low as possible. For example, it is preferable to control the aqueous phase temperature in the gas hydrate production reactor 1 to be in the range of 1 to 5 ° C. As a result, the solubility of methane in water can be increased, and the production equilibrium pressure can be reduced. The reaction between water and methane is an exothermic reaction, and when the reaction starts in the gas hydrate production reactor 1, the temperature inside the system rises due to the heat of hydration.
It is preferable to perform temperature control so that the system temperature is always maintained within a predetermined range.

The slurry-like methane hydrate MH thus efficiently produced is sent from the pipe 20 into the take-out device main body 31 of the dehydration device 30, and is supplied to the dehydration conveyor of the continuous dehydrator 33, which is a continuous dehydration means. It is supplied onto a 36 dewatering belt 35. Thereafter, the slurry-like methane hydrate MH is transported in the feeding direction by the dewatering belt 35 of the dewatering conveyor 36, whereby a plurality of dewatering mechanisms provided at intervals along the longitudinal direction of the dewatering conveyor 36 are provided. It is passed between 37 dewatering drums 41.

Thus, the slurry-like methane hydrate MH is compressed by the dewatering drum 41,
When the peripheral surface of the dewatering drum 41 is pressed directly or via the dewatering belt 35, the contained adhering water is removed from the peripheral surface of the dewatering drum 41 on the upper surface side to the dewatering belt 35 on the lower surface side. Is taken out from the peripheral surface of the lower dewatering drum 41 into each dewatering drum 41, stored in the storage part 31a below the unloading device main body 31, and then returned to the storage tank 3 through the pipe 49. Then, it is sent to the gas hydrate production reactor 1. Here, in each dehydrating mechanism 37, since the compressive force of the dehydrating drum 41 is sequentially increased in the methane hydrate MH feeding direction, the methane hydrate MH from which the adhering water has been removed by the upstream dehydrating mechanism 37 is removed. Thus, the adhering water in the methane hydrate MH is taken out by a compression force higher than the compression force by the dewatering drum 41 of the upstream side dewatering mechanism 37.

That is, the adhering water can be more efficiently extracted from the methane hydrate MH from which the adhering water has been extracted by the dehydrating mechanism 37 on the upstream side. The methane hydrate MH dehydrated stepwise by each dehydration mechanism 37 of the continuous dehydrator 33 is supplied to the dehydration conveyor 36.
Is scraped off by a scraper 43 provided on the sending side of the sheet, sent out to the next step, cooled and decompressed in the next step, molded into a predetermined shape, and transported.

As described above, according to the gas hydrate dehydrator 30 incorporated in the gas hydrate producing apparatus, the slurry methane hydrate MH transported by the dehydration conveyor 36 as the transport means is added to the peripheral surface. Dewatering drum 41 that has been subjected to mesh processing to impart water permeability
Is pressed while being rolled, water attached to the slurry-like methane hydrate MH can be very easily taken out from the peripheral surface of the dewatering drum 41 to dewater the methane hydrate MH. In other words, it is possible to easily and efficiently remove the attached water from a large amount of slurry-like methane hydrate MH containing the attached water to perform dehydration,
In addition, since methane hydrate MH is pressurized during dehydration, not only the hydrate is not decomposed, but also the effect that attached water is hydrated.

Also, slurry methane hydrate MH
Dehydration mechanism 37, which is a plurality of dehydration means along the transfer direction of
Is provided, the dehydration drum 41 of the dehydration mechanism 37 can continuously perform dehydration processing from the transferred slurry methane hydrate MH, and a large amount of slurry methane hydrate containing attached water. It is possible to easily and extremely efficiently remove the adhered water from the MH and perform dehydration. Moreover, in the plurality of dehydrating mechanisms 37 arranged along the transfer direction, the pressing force of the dehydration drum 41 against the methane hydrate MH is increased in order toward the delivery side, which is the rear side in the transfer direction. In addition, the attached water can be more reliably taken out and dehydrated from the slurry-like methane hydrate MH dehydrated by the upstream dehydration mechanism 37, and the dehydration can be performed at a high dehydration rate.

Further, the slurry methane hydrate MH to be transferred is sent between the pair of dewatering drums 41 so that the methane hydrate MH is sandwiched by the pair of dewatering drums 41 and the respective dewatering drums 41
From which water adhering to methane hydrate MH can be easily taken out. Further, since the transfer means is constituted by the dewatering conveyor 36 for transferring the slurry-like methane hydrate MH by the dewatering belt 35 subjected to mesh processing and imparted with water permeability, the slurry-like methane hydrate by the dewatering belt 35 is provided. During the transfer of the rate MH, the water adhering to the slurry-like methane hydrate MH can be taken out from the mesh of the dewatering belt 35, and the dewatering efficiency can be further improved.

Further, the methane hydrate MH after dehydration adhering to the dehydration belt 35 of the dehydration conveyor 36 can be scraped by the scraper 43 provided on the delivery side of the dehydration conveyor 36, and can be sent to the next step. The methane hydrate MH adhering to the peripheral surface of the dewatering drum 41 can be reliably scraped off by the scraper 42 provided along the peripheral surface of the dewatering drum 41, and can be reliably returned to the dewatering belt 35. In the above-described example, the dewatering drum 41 and the dewatering belt 35 are provided with water permeability by performing mesh processing on a plate made of a stainless steel plate. It goes without saying that any other device can be applied as long as it has the following.

[0055]

As described above, according to the gas hydrate dehydrator of the present invention, the following effects can be obtained. According to the gas hydrate dewatering device of the first aspect, the dewatering drum having water permeability is pressed against the slurry-like gas hydrate transferred by the transfer means while rolling, so that the dehydration drum can be extremely easily formed. Water attached to the slurry-like gas hydrate is taken out from the peripheral surface, and the gas hydrate can be dehydrated. In other words, it is possible to easily and efficiently remove the attached water from a large amount of slurry gas hydrate containing the attached water to perform dehydration, and at the time of dehydration, the gas hydrate is pressurized, so that the hydrate does not decompose. In addition, the effect that the attached water is hydrated is also exerted.

According to the gas hydrate dehydrating apparatus of the second aspect, the slurry gas hydrate transported by the transport means is rolled on the dehydration drum whose peripheral surface is subjected to mesh processing to impart water permeability. By performing the pressure contact while the pressure is maintained, it is possible to very easily take out the water adhering to the slurry-like gas hydrate from the mesh on the peripheral surface of the dehydration drum and perform the dehydration of the gas hydrate.

According to the gas hydrate dehydrating apparatus of the third aspect, since a plurality of dehydrating means are provided along the direction in which the slurry-like gas hydrate is transported by the transporting means, the dehydrating drums of these dehydrating means provide: The dewatering process can be continuously performed from the transferred slurry gas hydrate, and the dewatering can be performed easily and very efficiently by removing the adhered water from a large amount of the slurry gas hydrate containing the adhered water.

According to the gas hydrate dehydrating apparatus of the fourth aspect, in the plurality of dehydrating means arranged along the transfer direction, the pressing force of the dehydration drum against the gas hydrate is directed rearward in the transfer direction. Therefore, the adhered water can be more reliably taken out from the slurry gas hydrate dehydrated by the dehydrating means on the upstream side and dehydrated, and can be dehydrated at a high dehydration rate.

According to the gas hydrate dehydrator of the fifth aspect, the gas hydrate to be transported is fed between the pair of dehydration drums by causing the slurry-like gas hydrate to be transferred to be sandwiched between the pair of dehydration drums. The water adhering to the gas hydrate can be taken out from each dehydration drum, and the dehydration efficiency can be further improved.

According to the gas hydrate dewatering device of the sixth aspect, the transfer means is constituted by the dewatering conveyor for transferring the slurry-like gas hydrate by the dewatering belt having water permeability. During the transfer of the gas hydrate, the water adhering to the slurry gas hydrate can be taken out of the dewatering belt, and the dewatering efficiency can be further improved.

[0061] According to the gas hydrate dewatering device of the seventh aspect, the transfer means is constituted by a dewatering conveyer for transferring the slurry gas hydrate by a dewatering belt provided with water permeability by mesh processing. Since the slurry gas hydrate is transferred by the dewatering belt, the water adhering to the slurry gas hydrate can be taken out from the mesh of the dewatering belt, and the dewatering efficiency can be further improved.

According to the gas hydrate dehydrating apparatus of the eighth aspect, the dehydrated gas hydrate adhering to the dehydrating belt of the dehydrating conveyor is scraped off by the scraper provided on the delivery side of the dehydrating conveyor, and the process proceeds to the next step. Can be sent out.

According to the gas hydrate dehydrating apparatus of the ninth aspect, the gas hydrate adhering to the peripheral surface of the dehydrating drum is surely scraped and transferred by the scraper provided along the peripheral surface of the dehydrating drum. Can be returned to the means.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a gas hydrate dehydration apparatus according to the present invention.

FIG. 2 is a perspective view for explaining a dehydrating mechanism constituting a gas hydrate dehydrating apparatus according to the present invention.

FIG. 3 is a diagram showing a configuration example of a gas hydrate production apparatus incorporating the gas hydrate dehydration apparatus of FIG. 1;

4 (a) is an enlarged view of the spray means shown in FIG. 3, and FIG. 4 (b) is a view showing another embodiment of the spray means.

FIG. 5 is a hydrate generation equilibrium diagram.

FIG. 6 is a diagram showing a molecular structure of a hydrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas hydrate formation reaction device 30 Gas hydrate dehydration device 34 Roller 35 Dehydration belt 36 Dehydration conveyor (transfer means) 37 Dehydration mechanism (dehydration means) 41 Dehydration drum 42, 43 Scraper MH Methane hydrate (gas hydrate)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C10L 3/00 C10L 3 / 00Z (72) Inventor Masaharu Watanabe 2-1-1, Aramachi-Niihama, Arai-machi, Takasago City, Hyogo Prefecture. No. Within Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Yuichi Kondo 1-1-1, Wadazakicho, Hyogo-ku, Kobe, Hyogo Prefecture Inside Kobe Shipyard, Mitsubishi Heavy Industries, Ltd. (72) Inventor, Naoyoshi Fujita 1-1-1 Wadazakicho Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Takahiro Kimura 1-1-1, Wadasakicho, Hyogo-ku, Kobe-shi, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Hitoshi Endo 1-1-1 Wadazakicho, Hyogo-ku, Hyogo-ku, Hyogo Prefecture Inside Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Yoshihiro Kita Hyogo Prefecture 2-1-1 Shinhama, Arai-machi, Takasago-shi Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory F-term (reference) 4H006 AA04 AC90 AC93 AD33 BD60 BD81 BD82

Claims (9)

[Claims] 1. A gas hydrate dehydrator for dehydrating a slurry gas hydrate supplied from a gas hydrate generation reactor, comprising: a transfer means for transferring the slurry gas hydrate; and a slurry by the transfer means. A dehydrating unit provided in the middle of the transfer of the gas hydrate, the dehydrating unit having water permeability, and being pressed against the slurry gas hydrate transferred by the transferring unit while rolling. A gas hydrate dehydration apparatus comprising a cylindrical dehydration drum for removing water adhering to a slurry gas hydrate from a peripheral surface of the gas hydrate. 2. The dewatering drum is subjected to mesh processing to impart water permeability.
The gas hydrate dehydration apparatus according to the above. 3. The gas hydrate dehydrating apparatus according to claim 1, wherein a plurality of said dehydrating means are provided along a direction in which the slurry gas hydrate is transported by said transport means. . 4. The dehydrating means according to claim 3, wherein the pressing force on the gas hydrate is increased in the rearward direction of the transfer of the slurry gas hydrate by the transferring means. Gas hydrate dehydration equipment. 5. The dewatering means has a pair of dewatering drums urged in a direction to approach each other, and sandwiches a slurry gas hydrate by these dewatering drums, thereby removing the peripheral surface of each dewatering drum. The gas hydrate dehydration apparatus according to any one of claims 1 to 4, wherein water attached to the slurry gas hydrate is taken out. 6. The transfer means comprises a dewatering conveyor for transferring a slurry gas hydrate on the belt by moving a dewatering belt having water permeability by a roller, wherein the transfer means transfers the slurry gas hydrate. The gas hydrate dehydration apparatus according to claim 5, wherein the dehydration drums are provided on the front and back of the dehydration belt, and the slurry-like gas hydrate is sandwiched between the dehydration drum and the dehydration belt. 7. The gas hydrate dehydrator according to claim 6, wherein the dewatering belt is given water permeability by performing mesh processing. 8. The dewatering conveyor is provided with a scraper along a surface of the dewatering belt on a delivery side of a slurry-like gas hydrate to be transferred, for scraping off gas hydrate adhering to the dewatering belt. The gas hydrate dehydrator according to claim 6 or 7. 9. The scraper according to claim 1, wherein the dewatering drum is provided with a scraper along a peripheral surface for scraping off gas hydrate adhering to the slurry gas hydrate when pressed against the gas hydrate. A gas hydrate dehydration apparatus according to any one of the preceding claims.