JP4285600B2 - Gas hydrate production equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas hydrate production apparatus for producing gas hydrate from hydrate-forming substances such as natural gas, methane gas, and carbon dioxide gas.
[0002]
[Prior art]
In recent years, as a clean energy source and various material raw materials, a gas mainly composed of methane such as natural gas has attracted attention, and research for making natural gas or the like a gas hydrate has been conducted for transportation or storage. .
[0003]
This gas hydrate is also called a hydrate clathrate compound or a gas clathrate compound, and is a combination of a gas such as a lower hydrocarbon and a liquid (hydrate) such as water, which is formed by water molecules. It has a crystal structure in which the molecules of the gas falls one at a time into the basket, for example, in the methane hydrate, which is said to be occluded methane 164m ³ in methane hydrate of 1 m ³ under atmospheric pressure.
[0004]
Thus, since methane hydrate has a high gas storage property, it attracts attention as a new means for transporting and storing natural gas in place of liquefied natural gas (hereinafter referred to as LNG). The density of methane gas in methane hydrate is about 1 / 3.5 that of LNG, but it is not necessary to cool down to the liquefaction temperature of minus 162 ° C or less as in LNG, so energy efficiency is greatly improved. It is said that it will be done.
[0005]
By the way, aside from methane hydrate that exists in nature, when manufacturing methane hydrate artificially, in a pressure vessel holding the temperature at 1 to 10 ° C. and the pressure at 3.0 to 10.0 MPa. By supplying water and methane gas, which is a hydrate-forming substance, and reacting them, powdered snow-like or shaved ice-like methane hydrate is generated.
[0006]
As a method for producing a gas hydrate by causing a gas hydrate-forming substance such as LNG, methane gas, carbon dioxide gas and the like to contact and react with each other, a bubble stirring tank method and a spray method are conventionally known. .
[0007]
In this bubble agitation tank method, as shown in FIG. 8, water W is supplied into the agitation tank 1 of the high-pressure vessel in which the agitation blade 2 and the sparger 3 are arranged, and the water in the agitation tank 1 (water or antifreeze) Gas W, which is a hydrate-forming substance, is supplied as bubbles from the sparger 3 while stirring W with the stirring blade 2, and gas hydrate is generated by the contact reaction between the water W and the gas G.
[0008]
At this time, a large amount of heat of reaction (for example, 100 kcal per kg of hydrate) is generated. Therefore, a part of the water W is circulated from the lower part of the stirring tank 1 to the cooler 5 by the pump 4 and the cooling of the cooler 5 is adjusted to control the inside of the stirring tank 1 to have a predetermined temperature and pressure. ing.
[0009]
In the spray method, as shown in FIG. 9, a gas G, which is a hydrate forming substance cooled to a predetermined temperature by a cooler 7, is supplied from a nozzle 9 into a tank 6 of a high-pressure vessel. Water W is sprayed, and this gas G and water W are brought into contact reaction to generate gas hydrate.
[0010]
At this time, in order to absorb a large amount of reaction heat generated, a part of the gas G in the tank 6 is sucked by the blower 8 and circulated through the cooler 7 to be cooled, and the circulation amount of the gas G is adjusted. Thus, the inside of the tank 6 is controlled to have a predetermined temperature and pressure.
[0011]
[Problems to be solved by the invention]
However, in these conventional gas hydrate production methods, the reaction from the mixing of water and a gas that is a hydrate-forming substance to the production of gas hydrate is performed in a stirring tank or in a tank. It takes a lot of time to produce the water, and there is a problem in that it takes time to separate the water because of the large amount of water in the produced gas hydrate slurry.
[0012]
Furthermore, there is also a problem that the heat removal equipment becomes large in order to remove a large amount of reaction heat generated by the reaction between water and gas. In particular, the spray method requires a high-pressure gas circulation facility, a gas cooler, and the like in order to cool the gas, not the liquid, and the manufacturing apparatus is large and expensive.
[0013]
For example, in the bubble agitation tank method, 4 to 5 agitation tanks with a diameter of 6 mφ and a height of about 7 m are required in the case of equipment with 1 million t / year of methane. It becomes large.
[0014]
The present invention has been made in order to solve the above-described problems, and its object is to achieve a high gas hydrate production rate and a high efficiency and a low efficiency that can extremely reduce the moisture in the gas hydrate slurry. The object is to provide an apparatus for producing gas hydrate at low cost.
[0015]
[Means for Solving the Problems]
And the gas hydrate manufacturing apparatus of this invention for achieving said objective is comprised as follows.
[0016]
A gas hydrate comprising a tubular reactor comprising a long cylindrical body, a liquid supply means for supplying a liquid to the tubular reactor, and a gas hydrate forming substance supply means for supplying a gas hydrate forming substance to the tubular reactor In manufacturing equipment,
A plurality of tubular reactor units comprising a tube through which the mixture of the liquid and the gas hydrate forming substance passes and a jacket through which the cooling medium passes are arranged in series and / or in parallel. Connected to form the tubular reactor,
The reaction occurs while flowing the raw material supplied from the inlet of the tubular reactor inside said tubular reactor, wherein the discharged product from the outlet of the tubular reactor, and the tubular is separated from the product of unreacted starting material It is characterized by recycling to the inlet or intermediate part of the reactor .
[0017]
This tubular reactor is a reactor with a long cylindrical body, and a reaction occurs while the raw material supplied from one inlet of the long cylindrical body flows from one to the other inside the long cylindrical body. This refers to a reactor in which an object is discharged from the other outlet of the long cylindrical body. It also includes separating the unreacted raw material from the product and recycling it separately to the inlet portion or the intermediate portion.
[0018]
According to the gas hydrate production apparatus having this configuration, the liquid and the gas hydrate forming substance are mixed and supplied to one end of the tubular reactor in a state having a predetermined temperature and a predetermined pressure, and this mixed fluid is passed through the tubular reactor. The reaction heat is removed by the cooling medium or the like supplied to the jacket in the flow process, and the gas hydrate reaction proceeds.
[0019]
The tubular reactor can increase the efficiency of heat removal and piston flow, so the gas hydrate can be generated faster and the equipment is smaller than the bubble agitation tank and spray tank. it can.
[0020]
The generated gas hydrate is discharged from the tubular reactor as a gas hydrate slurry. By adjusting the mixing ratio, pressure and temperature of the liquid and the gas hydrate forming substance, the generated gas hydrate slurry The liquid content therein can be greatly reduced, and separation of the liquid and gas hydrate can be facilitated.
[0021]
And the connection of this tubular reactor unit is not limited to a serial connection, but in addition to a serial connection, a parallel connection, or a parallel connection and a serial connection can be combined. By forming multiple tubular reactor units connected in series, a relatively short tubular reactor unit is manufactured at the factory even when the manufacturing equipment becomes large, and this tubular reactor unit is connected in series on site. By doing so, it can be easily manufactured.
[0023]
Further, a portion of the tubular reactor, by providing a transfer means to feed transfer the generated gas hydrate slurry, more efficiently, can promote the reaction of the gas hydrate of.
[0024]
Alternatively, at least one of stirring means for stirring the generated gas hydrate slurry and transfer means for transferring the generated gas hydrate slurry is placed between the jacketed tubular reactor units constituting the tubular reactor. By providing, stirring and mixing corresponding to the change in physical properties due to the reaction step between water and gas becomes possible, so that the production of gas hydrate can be further promoted and the reaction of gas hydrate conversion can be promoted more efficiently.
[0025]
Further, in at least one of the tubular reactor units, at least a stirring means for stirring the produced gas hydrate slurry or a transfer means for transferring the produced gas hydrate slurry in the tube of the tubular reactor unit. By providing one, stirring and mixing corresponding to the change in physical properties due to the reaction process of water and gas becomes possible, so the generation of gas hydrate can be further promoted, and the reaction of gas hydrate conversion can be promoted more efficiently. it can.
[0026]
These stirring means and transfer means are preferably provided on the outlet side of the tubular reactor where the gas hydrate component in the gas hydrate slurry increases and the fluidity decreases. According to the gas hydrate manufacturing apparatus having such a configuration, the gas hydrate slurry generated in the tubular reactor and having relatively little moisture can be easily extracted from the tubular reactor.
[0027]
And, by providing a separator of specific gravity difference separation system that introduces the gas hydrate slurry produced by the tubular reactor and separates and discharges the gas hydrate on the outlet side of the tubular reactor, the gas from which moisture has been separated Hydrate can be obtained.
[0029]
In addition, by providing a static mixer for mixing the liquid and the gas hydrate forming substance on the inlet side of the tubular reactor, the liquid and the gas hydrate forming substance are previously mixed and supplied into the tubular reactor. Therefore, the generation of gas hydrate can be further accelerated.
[0032]
Furthermore, the internal pressure of the tubular reactor is controlled by providing a pressure maintaining device using a constant pressure gas in a pipe communicating with the tubular reactor. Moreover, you may provide the pressure maintenance apparatus by gas, ie, a bus gas hydrate formation substance, in a screw conveyor.
[0033]
The hydrate-forming substance in the present invention may be any substance that forms hydrates under predetermined pressure and temperature conditions. For example, methane gas, a mixed gas containing methane as a main component, and containing ethane, propane, butane, etc. Substances that are gaseous at normal temperature and normal pressure, such as natural gas, carbon dioxide, and chlorofluorocarbon, and substances that are liquid at normal temperature and normal pressure, such as tetrahydrofuran, furan, cyclopentanol, cyclopentanone, and ethylene oxide Including. Moreover, it can also be used as a hydrate-forming substance in a state in which liquefied gas or chlorofluorocarbon is in a liquid state.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a gas hydrate manufacturing apparatus according to the present invention will be described with reference to the drawings. In the following description, an apparatus suitable for the case where a gas such as methane gas is used as a raw material is shown, but it can also be applied to a case where a liquid is used as a raw material by making necessary modifications.
[0035]
As shown in FIG. 1, this gas hydrate production apparatus 1 includes a tubular reactor 11, a water supply means (liquid supply means) 14, a gas supply means (gas hydrate forming substance supply means) 15, a static mixer (mixing means). 16, the separator 17, and the screw conveyor 18 are comprised.
[0036]
The tubular reactor 11 is for generating a gas hydrate H from a mixed gas (gas hydrate forming substance) G and water (liquid) W, and is formed of a long cylindrical body. Although this tubular reactor 11 can be formed integrally, in consideration of manufacturing, etc., it is formed by a plurality (four in FIG. 1) of tubular reactor units 11u connected in series, and each tubular reactor unit 11u is The jacket 13 through which the cooling medium flows is disposed and formed on the outer periphery of the tube 12 through which the mixture of water W and gas G flows.
[0037]
In addition, regarding the connection of the tubular reactor 11, in addition to the serial connection shown in FIG. 1 and the like, there are cases where it is configured by a parallel connection or a combination of a parallel connection and a serial connection. The connection will be described as an example.
[0038]
The water supply means 14 is for supplying water W to the tubular reactor 11, is formed by a pump or the like, and is connected to the static mixer 16 by a water supply pipe 21. The gas supply means 15 is for supplying the gas G to the tubular reactor 11, is formed by a compressor or the like, and is connected to the water supply pipe 21 by a gas supply pipe 22.
[0039]
In order to control the internal pressure of the tubular reactor 11, a constant pressure gas pressure maintaining device (not shown) such as nitrogen gas is connected to a pipe (for example, the water supply pipe 21 or the gas supply pipe 22) communicating with the tubular reactor 11. You may provide, or you may provide the pressure maintenance apparatus (not shown) by the gas G in the screw conveyor 18. FIG.
[0040]
The static mixer 16 is for mixing the gas G and the water W, and is connected to the inlet side of the tubular reactor 11 by the mixture transfer pipe 23. The outlet side of the tubular reactor 11 is connected to a separator 17 by a slurry transfer pipe 24. This separator 17 separates the gas hydrate H generated in the tubular reactor 11 and sends it to the screw conveyor 18. The outlet side of the separator 17 is connected to the screw conveyor 18. The screw conveyor 18 is for transferring the gas hydrate H to a storage tank (not shown) or the like.
[0041]
In the gas hydrate production apparatus 1 having this configuration, the supplied water W and gas G are cooled to a predetermined temperature, for example, 1 to 10 ° C., by a cooling device (not shown), and then, a predetermined pressure, for example, 3 MPa to At 10 MPa (30 atm to 100 atm), the water W is supplied by the water supply means 14 via the water supply pipe 21, and the gas G is supplied by the gas supply means 15 to the water supply pipe 21 via the gas supply pipe 22. And enters the tubular reactor 11.
[0042]
Since the water W and the gas G are preferably mixed uniformly, a static mixer (or sparger) 16 is provided on the inlet side of the tubular reactor 11 as shown in FIG. The static mixer 16 includes a large number of nozzles 16a having fine nozzles, and the water G and the gas G are mixed into the water W by making the gas G into fine bubbles from the nozzle 16a. The nozzle 16a is formed by providing micropores in the pipe, arranging a large number of dispersion nozzles, or arranging a porous body having micropores or a porous body such as sintered metal at the gas outlet. can do.
[0043]
The mixture M of water W and gas G reacts while passing through the tube 12 of each tubular reactor unit 11u, and its composition changes to become gas hydrate H, and a gas hydrate slurry S with less moisture is generated. The
[0044]
A large amount of reaction heat generated in the process of generating the gas hydrate slurry S is removed by a refrigerant medium (brine) C such as an EG aqueous solution flowing in the jacket 13 outside the tube 12, and the temperature and flow rate of the cooling medium C are reduced. By adjusting and controlling the temperature and pressure in the tube 12 of each tubular reactor unit 11u, a predetermined temperature (for example, about 1 ° C. to 10 ° C.) and a predetermined pressure (for example, 3.0 MPa to 10.0 MPa) It is controlled to become.
[0045]
Therefore, the temperature of the cooling medium C may vary depending on the location of each tubular reactor unit 11u. For example, the temperature of the cooling medium C supplied to the outlet side is lower than the temperature of the cooling medium C supplied to the inlet side.
[0046]
The generated gas hydrate slurry S passes through the tube 12 and is introduced into the separator 17 via the slurry transfer pipe 24. The gas hydrate H is separated from the water W and the gas G by the separator 17 and is transferred and stored in a storage tank or the like (not shown) by the screw conveyor 18.
[0047]
Separation of the water W and the gas hydrate H in the separator 17 is performed by specific gravity difference separation using a point where the specific gravity of the gas hydrate H is smaller than the specific gravity of the water W.
[0048]
Next, the gas hydrate manufacturing apparatus 1A of the second embodiment shown in FIG. 3 will be described.
[0049]
In this gas hydrate manufacturing apparatus 1A, a drain pipe 25 that circulates water W separated by the separator 17 to the water supply means 14 and a gas vent that circulates the gas G remaining on the upper portion of the separator 17 to the gas supply means 15. A tube 26 is provided. Except for this configuration, the apparatus is the same as the gas hydrate production apparatus 1 of the first embodiment.
[0050]
With the configuration of the second embodiment, the cooled water W and gas G that have been cooled can be reused as the raw material for the gas hydrate H, so that the thermal efficiency and the raw material basic unit are improved.
[0051]
Next, the tubular reactor 11 will be described in more detail.
[0052]
The tubular reactor 11 may be integrally formed. However, when the gas hydrate manufacturing apparatus is implemented as an actual apparatus, the tubular reactor has a tube inner diameter of about 2 cmφ to 60 cmφ and a length of several hundred meters. In such a configuration, such a tubular reactor is manufactured and transported in a factory and is installed on the site, and transportation and installation work becomes difficult. In addition, the size of the tubular reactor unit can be changed in the middle. For example, the tubular reactor unit is thickened in a place where the reaction is slow.
[0053]
Therefore, as shown in FIGS. 1 and 3, a plurality of short tubular reactor units 11u, in which the tubular reactors 11 are connected in series, are constructed at the factory and serially installed at the installation site ( By connecting them in parallel or in a combination of parallel and series, manufacturing, transportation and installation work is facilitated.
[0054]
However, the shape, arrangement, and number of the tubular reactor units 11u in the tubular reactor unit 11u are not limited to those illustrated in FIGS. 1 and 3, and the number can be changed as necessary.
[0055]
FIG. 4 is a diagram showing a configuration of a tubular reactor 11A in which the tubular reactor units 11u are arranged horizontally. In the tubular reactor 11A, a plurality of tubular reactor units 11u are arranged in a substantially horizontal direction, and are connected in series (or in parallel). Or a combination of parallel and series).
[0056]
In the tubular reactor unit 11u on the inlet side of the tubular reactor 11A, since the amount of gas hydrate H produced is small, the tubular reactor unit 11u is rich in fluidity and easy to transfer. However, in the tubular reactor unit 11u on the outlet side, the gas hydrate H Since the amount of rate H generated is increased, the fluidity of the generated gas hydrate slurry S is deteriorated, and the transfer becomes difficult. Therefore, a screw (or a stirring blade with a transfer blade) 31 serving as a transfer means is provided in the tube 12. It is preferable that the screw 31 is used for transfer. More preferably, the whole or a part of the screw 31 is provided with a stirring blade or the like so as to function as a stirring means and to exert a mixing effect.
[0057]
At the same time, it is configured to be extracted by a screw conveyor 18 which is a gas hydrate extractor on the downstream side.
[0058]
FIG. 5 is a perspective view showing the configuration of a square-shaped tubular reactor 11B. In this tubular reactor 11B, a plurality of tubular reactor units 11u are arranged in a substantially horizontal square, and are connected in series (or in parallel, or Constructed in a spiral connection (in parallel and in series).
[0059]
4, a screw 31 is provided in the tube 12 of the tubular reactor unit 11u on the outlet side of the tubular reactor 11B, and the gas hydrate slurry S generated by the screw 31 is transferred while stirring. Configure. At the same time, the gas hydrate slurry S is extracted by the screw conveyor 18 on the downstream side.
[0060]
FIG. 6 is a perspective view showing the configuration of a spiral tubular reactor 11C. In this tubular reactor 11C, a plurality of bent tubular reactor units 11u are arranged in a spiral shape (spiral shape) around a vertical axis. Configured.
[0061]
4 and 5, the tubular reactor unit 11u on the outlet side is formed in a straight line, and a screw 31 is provided in the tube 12, and the screw 31 is transported while being agitated. It is configured to be extracted with.
[0062]
As shown in FIGS. 4 to 6, the tubular reactors 11 </ b> A and 11 </ b> B are used when the water W and the gas G are not particularly required to be separated from the generated gas hydrate slurry S or when they are separated in a later step. , 11C may be provided on the outlet side, and the separator 17 may be omitted.
[0063]
Instead of providing the screw 31 inside the tube 12 of the tubular reactor unit 11u, as shown in FIG. 7, a screw-type stirrer / transfer device 32 is provided between the tubular reactor units 11u to provide the gas hydrate slurry S. You may comprise so that it may transfer.
[0064]
【The invention's effect】
As is apparent from the above description, the gas hydrate production apparatus according to the present invention can provide the following effects.
[0065]
In the process of passing through the tubular reactor (piston flow type), a gas hydrate is generated by reacting a mixed fluid obtained by mixing a hydrate-forming substance and water, so that the gas hydrate generation rate can be increased.
[0066]
In addition, by adjusting and controlling the amount of water to be supplied and the amount of hydrate forming substance, the amount of water in the gas hydrate slurry extracted from the tubular reactor can be adjusted, and this adjustment greatly reduces the amount of water in the gas hydrate slurry. In addition, gas hydrate and water can be easily separated.
[0067]
Furthermore, the reaction heat generated in the tubular reactor can be easily removed by the cooling medium supplied to the jacket on the outer periphery of the tube, so that the heat transfer efficiency is improved, thereby reducing the size of the heat removal equipment and the construction cost. Reduction can be achieved.
[0068]
In addition, when a separator with dehydration is used, or when the amount of supplied water is less than the same amount of gas, the dehydrated gas hydrate can be transferred to the next step by a screw conveyor.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first embodiment of a gas hydrate production apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing a configuration of a static mixer or a sparger.
FIG. 3 is a diagram showing a configuration of a second embodiment of a gas hydrate production apparatus according to the present invention.
FIG. 4 is a diagram showing another configuration of the tubular reactor.
FIG. 5 is a diagram showing another configuration of the tubular reactor.
FIG. 6 is a diagram showing another configuration of the tubular reactor.
FIG. 7 is a diagram showing another configuration of the reactor.
FIG. 8 is a diagram showing a configuration of a gas hydrate production apparatus using a conventional bubble agitation method.
FIG. 9 is a diagram showing a configuration of a gas hydrate manufacturing apparatus using a spray method according to the prior art.
[Explanation of symbols]
1,1A Gas hydrate production apparatus 11, 11A, 11B, 11C, 11D Tubular reactor 11u Tubular reactor unit 12 Tube 13 Jacket 14 Water supply means (liquid supply means)
15 Gas supply means (gas hydrate forming substance supply means)
16 Static mixer (mixing means)
17 Separator 18 Screw conveyor 31 Stirring blade with screw or transfer blade (stirring means, transfer means)
32 Stirring blade with screw or transfer blade (stirring means, transfer means)

Claims (7)

A gas hydrate comprising a tubular reactor comprising a long cylindrical body, a liquid supply means for supplying a liquid to the tubular reactor, and a gas hydrate forming substance supply means for supplying a gas hydrate forming substance to the tubular reactor In manufacturing equipment,
A plurality of tubular reactor units comprising a tube through which the mixture of the liquid and the gas hydrate forming substance passes and a jacket through which the cooling medium passes are arranged in series and / or in parallel. Connected to form the tubular reactor,
The reaction occurs while flowing the raw material supplied from the inlet of the tubular reactor inside said tubular reactor, wherein the discharged product from the outlet of the tubular reactor, and the tubular is separated from the product of unreacted starting material A gas hydrate production apparatus for recycling to an inlet or an intermediate part of a reactor. 2. The gas hydrate manufacturing apparatus according to claim 1, wherein a transfer means for transferring the generated gas hydrate slur is provided in a part of the tubular reactor . At least one of stirring means for stirring the produced gas hydrate slurry or transfer means for transferring the produced gas hydrate slurry is provided between the jacketed tubular reactor units constituting the tubular reactor. The gas hydrate manufacturing apparatus according to claim 1, wherein In at least one of the tubular reactor units, at least one of stirring means for stirring the generated gas hydrate slurry or transfer means for transferring the generated gas hydrate slurry is provided in the tube of the tubular reactor unit. by providing gas hydrate production apparatus according to claim 1, wherein. The separator of specific gravity difference system for separating and discharging the gas hydrate by introducing the gas hydrate slurry generated by the tubular reactor is disposed on the outlet side of the tubular reactor . Gas hydrate production equipment. The gas hydrate production apparatus according to claim 1 , wherein a static mixer for mixing the liquid and the gas hydrate forming substance is provided on an inlet side of the tubular reactor . Claim 1, wherein the tubular reactor in either providing a pressure maintenance device according constant pressure gas pipe communicating, or providing a pressure maintenance device with a gas hydrate-forming material in the screw conveyor, 2, 3, 5 or 6, wherein Gas hydrate production equipment.

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