JP2002540223A - Hydrate generation, processing, transport and storage - Google Patents

Abstract

  (57) [Summary] The present invention relates to an economically advantageous method for producing, processing, transporting and storing fluids, especially natural gas, in the form of solid crystalline gas hydrates. It has been found that such fluids can be removed from a mixture of a hydrate, a liquid and optionally a gas using a two-stage fluid separation method, which is generally efficient but generally efficient. An expensive fluid removal efficiency separation scheme is used in the second stage. A number of separation devices are also disclosed. A method for economically storing and transporting hydrates is disclosed, as well as an apparatus for effectively and economically cooling substantially dry hydrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an economically advantageous method for producing, processing, transporting and storing fluids, in particular natural gas, in the form of solid crystalline gas hydrates.

[0002] Applications include the transport of gas from gas fields without existing local markets or without basic gas transport facilities and the export of associated gas from offshore oil fields without existing export or disposal means. The use of such a technique eliminates the need for environmentally undesirable methods of burning associated gases and gases released during well testing operations.

[0003] A gas hydrate is an ice-like crystal structure that is primarily composed of water molecules during the production of any gas molecules that fall into a molecular scale cavity within the crystal structure. A unit volume of the hydrate can contain more than 150 volume parts of the gas when the gas is at 20 ° C. at atmospheric pressure.

[0004] Hydrates can be formed with only a limited range of compounds including methane, ethane, propane, butane, isobutane, carbon dioxide, hydrogen sulfide, tetrahydrofuran and chlorofluorocarbons. The first six compounds mentioned above make up the majority of most natural gas fields.

[0005] The formation of hydrates is greatly affected by temperature and pressure. In the case of natural hydrocarbon gas, hydrates are typically 0 ° C. only at pressures above about 15 bar as shown in FIG.
(Ice formation temperature) or more. Hydrate formation in pipelines and equipment is thus awkward in offshore oil and gas fields, and expensive measures are being used to prevent it. The thermodynamics and properties for basic hydrate formation are well understood and described in the literature, for example, Sl
See oan ED, "Clathrate Hydrates of Natural Gases," Marcel Dekker, New York, 1990.

[0006] The ability to convert a gas into the form of a solid hydrate is a potential for several purposes, including storage or long-distance transport due to the large amount of gas the hydrate can contain in a unit volume. Is useful. Over the years, ie, at least dating to 1942, several methods for achieving these objectives have been proposed and patented. See, for example, U.S. Patent No. 5,536,893.

The detailed mechanism of hydrate formation is based on whether the hydrate forming substance is a gas, a liquid immiscible with water, or a miscible liquid under contact conditions. Is determined by
Most of the prior patents are directed to the production of hydrates from gas, where the production of hydrates occurs at the gas-water interface, and the proposed production reactor is: A contact device that provides a large interface area to facilitate rapid production. The engineering principles of some suitable contactor types are well known, and most prior patents disclose single-stage sprays (see U.S. Pat. Nos. 2,399,723 and 568,2).
No. 90) or foaming pool ("bubble tower", "gas injection tower")
It relates to the use of a reactor (see, for example, U.S. Pat. Nos. 3,975,167 and 3,514,274). The latter type is
Technical improvements are often made through the use of mechanical stirrers.

[0008] Recent prior art documents (eg, WO 97/26494) have focused on the optimal arrangement of processing plants for the production of gas hydrates.

Under the process conditions proposed by most prior art, the effluent from the reaction vessel consists of a mixture of the resulting hydrate with a significant amount of unreacted water in the form of a mixed slurry. . This is a convenient form for continuously removing the hydrate product from the production reactor. However, mixed slurries containing significant amounts of unreacted water,
It is bulky and agglomerated, so the processing, transport and storage equipment must be correspondingly large to contain the slurry. All of the prior art, despite fifty years of research and development, have not developed an economically advantageous system for any of the intended applications. To the inventor's knowledge, none has achieved commercial use.

[0010] Applicants have implemented an experimental program to study the production of a range of gas hydrates and their treatment, and then investigated the storage properties of those hydrates. This work has led to the development of a new combination of technologies that together constitute an economical means for the production, processing, transport and storage of gas hydrates described in many of the above mentioned technical literatures.

According to a first aspect of the invention, there is provided an apparatus for removing a fluid from a two-phase mixture of a hydrate and a liquid at a high pressure or from a three-phase mixture of a hydrate, a liquid and a gas at a high pressure, A first separation device having a first fluid removal efficiency for receiving an input mixture of hydrate and liquid or hydrate and liquid and gas and producing an intermediate mixture having a higher concentration of hydrate than the input mixture; A second separation device having a second fluid removal efficiency higher than the fluid removal efficiency of the first separation device, wherein the second separation device is provided in a closed pressure vessel, and the intermediate mixture is subjected to high-pressure separation. A centrifuge for receiving from the first separation device at, and producing an essentially solid hydrate or concentrated hydrate slurry output.

[0012] Higher fluid removal efficiency is related to the ability of the device to produce a higher concentration of solids for the same input mixture. Adopt high pressure higher than atmospheric pressure. Hydrate production plants, such as those disclosed in WO 97/26494, generally operate at elevated pressure, and the hydrate slurry obtained from the plant will be at elevated pressure. By providing a centrifuge with high fluid removal efficiency in a closed pressure vessel, the centrifuge can operate at high pressure. By maintaining high pressure in the first and second separators, the hydrate is maintained at stable conditions without the need for excessive cooling schemes, which can be very expensive.

The Applicant has determined that a proportion of the liquid and, if applicable, the gas may be divided between the hydrate and the liquid.
By essentially removing the phase mixture or hydrate, liquid and gaseous three-phase mixture, and then feeding it to a second, generally expensive, but highly liquid-efficient separator (including a centrifuge), It has been found that the number and volume of high efficiency separators required are significantly reduced while increasing the quality of the same quality output of solid hydrate or concentrated slurry. This significantly reduces costs and increases the level of production that makes the use of hydrates more commercially attractive.

Providing a device with two separation devices with different liquid removal efficiencies allows the production of essentially liquid-free hydrates at a reasonable cost. Even with the use of one or more separation devices with low liquid removal efficiency, the final product will still contain excess liquid. With a series of separation devices with high liquid removal efficiency, such devices would be prohibitively expensive.

The Applicant requires that the final production form of an essentially solid or concentrated slurry require handling of hydrate products that are stable at substantially lower pressures than those required for hydrate production. It has been found to be particularly useful for applications.

The apparatus according to the second aspect of the present invention can be used as at least a part of the first separation apparatus according to the first aspect of the present invention for separating a gas from a three-phase mixture of a hydrate, a liquid and a gas. ,
A container having an inlet for receiving a three-phase mixture of hydrate, liquid, and gas, the container having an inner surface, wherein the mixture is applied to the inner surface and gas impacts the mixture from the mixture on the inner surface; The container has a chamber for collecting the remaining mixture after the mixture has been applied to the inner surface, the chamber comprising an outlet and a hydrate floating above the liquid in the chamber during use. To the outlet.

The means for directing solids floating on the liquid in the chamber to the outlet is an upper boundary of the chamber, wherein at least a part of the upper boundary is, during use, such that the outlet has an inclined portion of the upper boundary. It is preferably inclined at an upper part of a chamber formed below the horizontal line.

The gas, liquid, and solid hydrate separation device according to the third aspect of the present invention can be used as the first separation device according to the first aspect of the present invention. A container for receiving the input mixture of solid hydrates, filtration means provided within the container, and means for directing the input mixture of gas, liquid and hydrate to the filtration means, thus producing a gas. The liquid is collected or removed from the upper portion of the container, the liquid is collected or removed from the lower portion of the container through the filtering means, and the hydrate is collected by the filtering means. The filtering means may be, for example, a perforated screen or a non-woven mesh.

The final production form of the essentially solid or concentrated slurry that can be produced in accordance with the first aspect of the invention is preferably stored or transported so that it can remain stable for an extended period of time. Is cooled.

Cooling solid or concentrated slurries is difficult and expensive because of the poor heat transfer properties of such systems and the need to avoid freezing of solids in front of the cooling device.

The present inventor has solved this problem with a substantially dry hydrate cooling device as another feature of the present invention, wherein such a hydrate cooling device is essentially solid or concentrated. A vessel for receiving the slurry hydrate and a gas distributor configured to supply a fluidizing gas during use, the gas distributor essentially drying the fluidizing gas within the vessel during use. The hydrate or the concentrated slurry hydrate is positioned in the vessel to fluidize the hydrate through the hydrate; It further has means for passing through the object.

[0022] The means for passing the cooling medium through the fluidized hydrate in the vessel is preferably a gas distribution device configured to supply a cooled fluidized gas. Alternatively or additionally, the means for exerting a cooling effect on the hydrate may be a means for providing a flow of cooling fluid into the fluidized hydrate to exert a cooling effect. The flow of this cooling fluid is 1
Alternatively, the fluidized hydrate may be passed through two or more conduits.

According to yet another aspect of the present invention, a gas in the form of a stable hydrate, preferably used for a hydrate prepared using one or more of the above features of the present invention. A method is provided for performing storage and / or transportation.

Next, the present invention will be described by way of example with reference to the accompanying drawings.

FIG. 2 schematically illustrates a system according to the first aspect of the invention for the two-stage removal of fluid from a hydrate-liquid two-phase mixture or a hydrate-liquid-gas three-phase mixture. Is shown in The mixture is supplied to a first stage (stage) 3 of the fluid removal system 2.
The first stage 3 mechanically removes hydrates floating on the liquid, which is a liquid separated from a hydrocyclone or a slurry described below, such as any suitable separation device known in the art. It should be a device. The output 4 from the first stage 3 is sent to a second stage 5, which is a more efficient separation device than the first stage, in this case provided in a pressure vessel. A centrifuge that produces a substantially dry hydrate product 6.

FIG. 3 is a schematic diagram of a hydrate production method tested using pilot plant and laboratory experiments, which utilizes the fluid removal system shown in FIG. For example, a process reactor 10 as shown in Applicant's earlier International Application Publication No. WO 97/26494 produces a hydrate / gas / liquid mixture 11. The mixture 11 is sent to an apparatus 12 described below configured to separate a majority of the gas phase from the mixture 11. The separated, substantially liquid and solids-free gas stream 13 can be used, for example, to return to the process reactor 10 to produce further hydrates, or to be sent to a power generation device, or to burn it. Is also good.
The substantially gas-free liquid and solids slurry stream 14 is provided to the first water removal system 2.
The first separation device 15 which forms a stage 3 of which the hydrate concentration is higher than that of the liquid stream 16 and the input stream 14 containing a constant level of solids, as described below. Is configured to produce a high slurry flow 17. The liquid stream 16 is returned to the process reactor 10 for use in producing further hydrates. As a modification, the gas separator 12 and the first separator 15 may be combined to form a single device 30 described below.

The slurry stream 17 is sent via an optional cooling device 18 to a second stage of the water removal device 2, which is more efficient than the first stage 3 separation device. And a separation device 5 having a high density. The second stage separator is a centrifuge that is provided in the pressure vessel and allows the fluid to be separated at high pressure and remain stable without the need to cool the hydrate excessively. The inventor has determined that the continuous sorting centrifuge 5 comprises a 95% to 99.5% liquid-free stream 19 in the form of a granular free flowing solid and a process reactor 1.
It has been discovered that it produces a liquid stream 20 containing very low levels of solids that can be returned to zero. Centrifuges have been found by the present inventors to be particularly suitable for large-scale applications.

The stream 19 is optionally fed into a device 21, where it is cooled by direct contact with a gas stream 22 supplied at high pressure and low temperature, or through the body and walls of the device. It may be indirectly cooled by passing a flow of additional cooling medium 23 through the extending conduit, but this is optional. This latter option adds to the complexity of the process, but requires a small amount of high pressure gas stream 22 to facilitate the movement of solids and improve heat transfer to the solids, referred to as "fluidization." It just does. The gas stream 22 may be either a hydrate-forming gas or a non-hydrate-forming gas, but in the former case the water entering the device 21 in the stream 19 may be converted to additional hydrates. The advantage that it can be obtained is obtained.

The fluidizing / cooling gas 22 and the cooling medium 23 are separately (streams 24, 25)
Get out of one. The dried room temperature solids stream exits apparatus 21 and is preferably decompressed to atmospheric conditions by apparatus 26 and loaded into transport or storage apparatus 27.

The gas separation device 12 may be of the type shown in FIG. The input stream 11 is adapted to enter a pressure vessel 40 capable of withstanding the high pressures that the input stream 11 reaches from the hydrate manufacturing plant. The input stream 11 enters the pressure vessel 40 via the inlet 41, in this case a suitably shaped section 42 of the inlet
Is directed downwards by Gases present in the input mixture 11 are released from the mixture by impinging the mixture on a suitable surface 43, in this case a part of the insert 44. The resulting gas leaves the vessel via outlet 45 as gas stream 13. Surface 43 pumps the remaining liquid and solids from the mixture into downcomer 46, which is dimensioned such that hydrate particles are entrained in the downward flow (known). Method). The insert 44 has an upper boundary 48
Are shaped to create a space or chamber 47 at the bottom of the container 40 with the upper boundary 48 which is inclined or inclined with respect to the horizontal in use. A withdrawal 49 of the substantially gas-free liquid and solids slurry stream 14 is located at the top of this chamber 47 and has a sloped or sloping upper boundary 48.
Is arranged to direct the hydrate floating on the liquid in the chamber 47 to the extracting section 49. This design avoids hydrate build-up in the device and consequent clogging.

In operation, the level of liquid collected in or above the downcomer is maintained so that hydrates can be entrained in the downward flow into chamber 47. It has been found that the flow of liquid into the downcomer 46 generally produces a vortex entrained with hydrate in the downward flow. Maintaining the level of the liquid in or above the downcomer during use, prevents separated gas from flowing into chamber 47 or out of outlet 49 to provide substantially gas-free liquids and solids. Creates a seal that results in a slurry flow 14 per minute. Maintaining the liquid / hydrate slurry surface level in or above the downcomer includes a first level sensor 401 positioned at the lowest liquid level in downcomer 46, a maximum in or above downcomer 46. This can be achieved by using a second level sensor 402 positioned at the liquid level, a valve 403 connected to the outlet 49 and control means 404 connecting these together via a control line 405. When the liquid level in the downcomer falls to the lowest level, the first level sensor 401 is activated and the control means 404 causes the valve 40
3 is closed, the liquid level in the downcomer 46 rises due to the continuous addition of flow from the input 11 and hydrates are trapped in the downward flow of liquid in the downcomer 46. So that Conversely, when the maximum liquid level sensor 402 is activated, the control means 404 opens the valve 403 to allow water and hydrate to flow out of the outlet 49 to lower the liquid level.

The chamber 47 may be provided with a water outlet 404 provided at the bottom thereof for drawing water out of the chamber 47 and thus increasing the concentration of hydrate from the outlet 49. By positioning the water outlet 404 at the lower part of the chamber 47,
Hydrates floating above the water in the room are less likely to be drawn through the water outlet 404, especially when using the liquid control system described in the preceding paragraph. However,
Filter 405 may be provided at the outlet to prevent hydrate from flowing into water outlet 404.

Either of the two preferred devices can serve the function of the separation device 15. 1
One is a hydrocyclone, a device that is well known to those skilled in the art of solid-liquid separation, but is typically used to separate solids from liquids of lower density than in the present invention. .

According to the results of studies carried out by the applicant, an alternative device 15 suitable for the invention requires the separation of solids from dense liquids. This device is shown in FIG. Stream 14 enters vessel 50 of apparatus 15 via inlet 51 and is directed upward by a suitable portion 52 of the inlet.

Liquid stream 16 is withdrawn from the bottom of the container through outlet 53. The diameter of the container 50 is such that the hydrate particles are not drawn down by the flow of liquid in stream 16, instead the hydrate forms a floating mass 54 in the upper portion of the container 50. Get together to do it. The mass of hydrate 54 floats on the liquid in the container. The portion of the mass consisting of the hydrate 54 floating on the surface of the liquid is drained by gravity. A scraping device 55 provided at the top of the container 50 scrapes the hydrate at the top of the floating mass 54 toward the outlet 56 to form a stream 17.

An apparatus 30 that can be used as an alternative to the combination of the apparatuses 12 and 15 is shown in FIG. This device 30 is provided with an input stream 1 from a hydrate production plant.
It has a filtering means, in this case a perforated screen 60, provided in a pressure vessel 61 which withstands a pressure of 1. Stream 11 enters the vessel through inlet 62 and is directed downward by a suitable dispensing device 63, which may be a suitably directed portion of inlet 62. Inlet stream 11 is applied to surface 60 with sufficient force to generate gas.

The gas stream 13 is generated by applying an input hydrate / liquid / gas mixture to a screen 60, and the resulting gas stream 13 exits the top of the vessel 61 through a gas outlet 64. Liquids and hydrates that hit the screen 60 travel under the screen under the influence of gravity in the direction shown. During this passage, the liquid passes through holes in the screen 60. Operation of the device 30 at high pressure, as generally required to maintain the hydrate in a stable state, increases the amount of liquid passing through the holes in the screen 60, thus providing good separation. Will be The concentrated slurry (stream 17) is withdrawn from the vessel through outlet 65. Liquid 66 passing through screen 60 accumulates at the bottom of container 61 and is withdrawn from the container as stream 16 through outlet 67. Laboratory testing at process conditions has shown that such a device is 5% by volume.
That is, a stream containing less than 30% hydrate can be concentrated to a stream containing 30% or more hydrate.

The second more efficient stage 5 of the two-stage water removal device is, in this embodiment, a pressure vessel 32
A centrifuge 71 provided in the inside. The centrifuge 71 has a wire mesh or mesh ring 73 serving as a sorting surface. The centrifuge is mounted on an axis 74 supported by the pressure vessel 32 in a rotatable configuration about the axis on the appropriate side. If desired, plate and blade (not shown) structures may be provided inside the centrifuge to aid in separation. First stage 3 of two-stage water removal system 2
Is sent to the centrifuge 73 via the inlet 75. Due to the rotation of the centrifuge, water is forced through the sorting surface and collected at the bottom of the pressure vessel 72, while hydrates accumulate inside the sorting surface. A duct 76 is provided below the centrifuge 71 to receive the hydrate adhering and accumulating inside the centrifuge 71 and to allow the hydrate to flow out of the pressure vessel 72 through the hydrate outlet 77. Water collected at the bottom of pressure vessel 72 is collected via liquid outlet 78. Thus, the centrifuge 73 produces a continuous hydrate stream. Laboratory tests using small pressure centrifuges show that full-size (full-size) centrifuges can produce hydrate products containing less than 2% by volume of water. it can.

The device 21 is a fluidized bed (bed) in this embodiment. According to the applicant's knowledge,
Fluidization of hydrates and ice particles can be performed at low temperatures and high pressures. In laboratory tests, fluidized beds of hydrates and ice particles were able to fluidize smoothly at temperatures below -10 ° C when high pressure was maintained. The experiments were carried out at a temperature between -10 <0> C and -70 <0> C and a pressure between 3.5 and 28 bar. By comparing the heat transfer coefficient obtained in apparatus 21 with the heat transfer rate found in conventional refrigeration equipment for a substantially solids stream, the inventor concludes that this is a temperature suitable for transporting the hydrate product to transport. Moderate cooling has been found to be the most economical way.
FIG. 8 shows the structure of such a layer. Layer 80 is housed in a pressure vessel 81 suitable for the pressure and temperature required to perform the process. The pressure vessel 81 is a container 81
Is formed with a layer 80 configured to be provided in a lower portion 82 of the base. The upper portion 83 of the container 81 is configured to send fluidized particles from the lower portion 82 back to the lower portion. In the embodiment shown in FIG. 8, this is achieved by providing a beveled lip 84 around the upper periphery of the lower portion 82 to allow particles exiting the layer 80 to fall into the container 81.
This is achieved by sending back to the lower part of This structure houses the layer 80,
Prevent small solid particles from being carried away from the top of layer 80 (alternatively shaped internal components may be used to construct the desired geometric layer in a more conventional shaped pressure vessel). The solids from the separator 5 are added to the bed 80 via the inlet 85 so that these solids fall into the bed. Fluidizing gas 22 is introduced through inlet 86 and then through distribution system 87 to a majority of the bottom of the bed. The fluidizing gas 22 is preferably a hydrate forming gas, so that the moisture entering the fluidized bed from stream 19 is converted to a hydrate, which keeps the hydrate virtually dry. The fluidizing gas 22 can also have a cooling effect on the hydrate in the bed 80. If desired, cooling medium 23 from one or more external sources, such as evaporative refrigerant, may be passed from distribution system 87 to bed 80 with the fluidizing gas. Fluidizing gas 22 exits bed 80 and optionally exits vessel 81 via outlet 88 after passage through a conventional cyclone device 89 to remove ice and small entrained particles of hydrate. As shown in FIG. 8, the cooling medium may be passed through the fluidized bed with a conduit 90 made of a material with good thermal conductivity, preferably a metal, for example steel. It is preferable to use a liquid coolant capable of absorbing a much larger amount of heat than a gas coolant and exerting a good cooling effect by passing a cooling medium through a fluidized bed through a conduit. As more solids are added to fluidized bed 90, the level of the fluidized bed rises and solids overflow from fluidized bed 90 via chute 91 and outlet 92, thereby substantially maintaining the level of fluidized bed 90. To maintain. In some environments, such as large facilities, the layers may be subdivided by a series of substantially vertically oriented baffles 93, only one of which is shown in FIG. By adding such a baffle, the gas flows from the first temperature inlet area 93a to the lower temperature outlet area 93b.

The pressure reducing device 26 shown schematically in FIG. 3 may be any of a variety of known techniques for reducing the pressure of a solids stream. Applicants have noted that a batch of solids is introduced into a pressurized vessel, then the vessel is isolated by a valve, and then optionally the re-compression cost is initially directed to the exhaust gas to a previously depressurized vessel. Uses a savings lock hopper system.

Any means of transferring or storing the cooled bulk solid mass of hydrate may be used as appropriate. Such examples may be containers, holds, or rail vehicles. The transport or storage means is preferably insulated.

Economic studies have shown that the gas content of the hydrate used for transport or storage is preferably between 150 and 200 volume units of gas per hydrate volume (at atmospheric pressure and temperature conditions). Gas). If the gas content of such hydrates is not achieved, it will be necessary to use a large number of such large or small vessels or containers, thereby reducing the need for other known alternatives for gas storage or transportation. The use of hydrates would be uneconomical.

The Applicant surprisingly, according to yet another feature of the present invention, stores or transports hydrates in which at least a majority of the hydrates remain stable for at least 24 hours. It has been found that this can be achieved by keeping the stable hydrate in a lump without the need for external cooling.

FIG. 9 shows the temperature curve of such a hydrate mass in a hold with an internal storage temperature of −50 ° C. after 5 days. Ambient temperature at the top of the hold is 20
° C and the ambient temperature at the bottom of the hold is 15 ° C. As you can see,
Only the edges of the original hydrate mass are below the stable temperature of about -37 ° C at ambient pressure and are converted to water (ice) and natural gas. Most of the hydrates, in this case 95%
However, it remains as a stable hydrate, with only 5% being converted to natural gas and water in the form of ice.

Although insulation of the hydrate mass is not required, its use is preferred in certain circumstances. This is because it increases the length of time that the hydrate remains stable. Whatever transport or storage device is used, for example in holds, containers or rail vehicles, it may be desirable to provide thermal insulation.

As the size of the hydrate mass increases, the edges of the hydrate mass only break down to ice and gas within the normal transport or storage period of several days, and thus become stable over the same period of time. The proportion of hydrates that remain remains increases. Preferred agglomerates of hydrate for use in the present invention have a minimum dimension of 2 m in any direction, with a more preferred dimension being at least 10 m in any direction. However, this is, of course,
Determined by the expected duration of transport or storage.

The hydrates used in the storage and transport methods described above are preferably substantially pure to produce commercially useful volumes of gas in suitably small amounts of hydrates.

The hydrate used in the storage and transport methods described above is preferably a substantially dry or concentrated slurry to reduce the proportion of non-gas-containing materials to be stored or transported, This makes the storage or transportation method of the present invention more economically attractive.

Many design modifications of the embodiments described above are possible without departing from the scope of the invention as set forth in the claims. For example, any suitable first separation device may be used in a two-stage device for removing fluids from hydrates, liquids and optionally gas mixtures.

[Brief description of the drawings]

FIG. 1 shows a typical natural gas hydrate equilibrium curve showing the pressure and temperature conditions required for the production of a stable hydrate, with the stable hydrate positioned above this curve. I have.

FIG. 2 schematically shows an apparatus according to a first aspect of the invention for the production of an essentially rectangular or concentrated slurry of hydrates.

FIG. 3 schematically shows a series of steps in a method for producing a hydrate using the method according to the first aspect of the present invention.

4 shows a preferred apparatus for performing the various steps of the method shown in FIG.

5 shows a preferred apparatus for performing the various steps of the method shown in FIG.

6 shows a preferred apparatus for performing the various steps of the method shown in FIG.

7 shows a preferred apparatus for performing the various steps of the method shown in FIG.

FIG. 8 shows a preferred apparatus for performing the various steps of the method shown in FIG.

FIG. 9 is a schematic diagram showing the temperature of various regions of a hydrate mass stored in a hold for 5 days at ambient temperature and pressure.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 9/02 C07C 9/04 9/04 9/06 9/06 9/08 9/08 C10L 3/00 A (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AU, CA, CN, ID, IN, JP, LK, MX, NZ, PL, TR , TT, US, VN, ZA (72) Inventor Williams Richard Richard Leicestershire EL10 2Dee Hinckley Barbage Church Street G 121 (72) Inventor Haines David Alan United Kingdom Loughborough LEE 12 8P J Barrow upon So Beaumont Road 98 (72) Inventor Taylor Mark Raymond United Kingdom Raystar EL2 5E Sue Rosemed Drive 8 F Term (Reference) 4H006 AA02 AC90 AD30 AD33 BE60

Claims (42)

[Claims] A device for removing a fluid from a two-phase mixture of hydrate and liquid at high pressure or from a three-phase mixture of hydrate, liquid and gas at high pressure, comprising a hydrate and a liquid or hydrate A first fluid removal efficiency first separation device that receives an input mixture of liquid and gas and produces an intermediate mixture having a higher hydrate concentration than the input mixture;
A second separation device having a second fluid removal efficiency higher than the fluid removal efficiency of the first separation device, wherein the second separation device is provided in a closed pressure vessel to remove the intermediate mixture. An apparatus comprising a centrifuge that is received at high pressure from a first separator and produces an essentially solid hydrate or concentrated hydrate slurry output. 2. A first separating device comprising: a container for receiving an input mixture of hydrate and liquid; means for removing hydrate floating on the top of the mixture; and removing liquid from a lower portion of the container. 2. The apparatus of claim 1, further comprising: 3. The apparatus according to claim 2, wherein the means for removing hydrate floating on the top of the liquid is a scraper configured to direct the removed hydrate to an outlet. . 4. The apparatus according to claim 1, wherein the first separation device is a hydrocyclone. 5. A first separation device comprising a container having an inlet for receiving a three-phase mixture of hydrate, liquid and gas, said container having an inner surface, said mixture being applied to said inner surface. The container is configured to cause gas to escape from the mixture upon impact of the mixture on the inner surface, the vessel having a chamber for collecting the remaining mixture after applying the mixture to the inner surface, the chamber comprising an outlet and a use outlet. 2. The device of claim 1, further comprising means for directing the hydrate floating on the liquid in the interior chamber to the outlet. 6. The means for directing solids floating on the liquid in the chamber to the outlet is an upper boundary of the chamber, at least a part of which, when in use, has an outlet in the upper boundary. 6. The device according to claim 5, wherein the device is inclined with respect to a horizontal line at a position above the chamber formed below the inclined portion. 7. The interior surface of the container to which the mixture has been applied is a surface which, in use, is located above the chamber and which lowers the mixture remaining after applying the mixture to the surface to the chamber. 7. A tube according to claim 5, wherein a tube is provided.
The described device. 8. The apparatus of claim 7, wherein the inner surface of the container is shaped to direct the remaining mixture after application of the mixture to the inner surface to the downcomer under the action of gravity during use. 9. A first separating device comprising: a container for receiving an input mixture of gas, liquid and solid hydrate; a filtering means provided in the container; and a filter for filtering the input mixture of gas, liquid and hydrate. Means for directing it against the means, thus producing gas to collect or remove from the upper part of the vessel, wherein the liquid is collected or removed from the lower part of the vessel through filtration means, and the hydrate is collected. The apparatus of claim 1, wherein the apparatus is adapted to be collected by a filtering means. 10. The filtration means is a perforated screen, wherein the perforated screen is configured such that hydrates collected by the screen move down the screen and are collected or removed from a container. The device according to claim 9, characterized in that: 11. The screen is curved, and the means for directing the mixture against the screen comprises: directing the mixture downward and onto the screen, wherein the hydrate collected by the screen has its kinetic component in an arc. 12. The device of claim 11, wherein the device is configured to slide off the screen. 12. A hydrate cooling device for cooling the essentially dry hydrate or concentrated slurry output obtained by the second separation device, wherein the hydrate cooling device comprises A container for receiving a solid or concentrated slurry hydrate;
A gas distributor configured to supply a fluidized gas during use, the gas distributor comprising an essentially dry hydrate or a concentrated slurry hydrate in the vessel during use. Wherein the hydrate cooling device includes, during use, means for passing a cooling medium through the fluidized hydrate in the container. The device according to any one of claims 1 to 11, further comprising: 13. The apparatus according to claim 12, wherein the means for passing the cooling medium through the fluidized hydrate in the vessel is a gas distributor configured to supply a cooled fluidized gas. . 14. The method of claim 12, wherein the means for passing the cooling medium through the fluidized hydrate is a means for sending a flow of the cooling gas into the fluidized hydrate separately from the fluidized gas. 13. The apparatus according to claim 13. 15. Apparatus according to any one of claims 12 to 14, wherein the gas distribution device is configured to be supplied with a hydrate forming fluidizing gas. 16. An apparatus for braking an essentially solid hydrate or concentrated hydrate slurry substantially as described with reference to the accompanying drawings. 17. The method according to claim 1, further comprising the step of producing the hydrate in a stable form.
A method for storing or transporting hydrates produced by the apparatus according to any one of the preceding claims. 18. The method of claim 17, wherein the hydrate is an essentially dry hydrate or a concentrated slurry hydrate. 19. The method according to claim 17, wherein the hydrate is provided in an insulated container. 20. The method according to claim 17, wherein the hydrate is obtained as a large mass having a minimum dimension of 2 m in any direction. 21. A method of storing or transporting a hydrate substantially as described with reference to the accompanying drawings. 22. An apparatus for separating gas from a three-phase mixture of hydrate, liquid and gas, comprising a container having an inlet for receiving a three-phase mixture of hydrate, liquid and gas, wherein the container Has an inner surface, the mixture is applied to the inner surface, and gas is released from the mixture by impact of the mixture on the inner surface, and the container is configured to:
Having a chamber for collecting the remaining mixture after applying the mixture to the inner surface, the chamber having an outlet and a means for directing hydrates floating on the liquid in the chamber during use to the outlet. Characteristic device. 23. The means for directing solids floating on the liquid in the chamber to the outlet is an upper boundary of the chamber, at least a portion of which is configured such that, in use, the outlet has an upper boundary with the upper boundary. 24. The apparatus according to claim 23, wherein the apparatus is inclined with respect to a horizontal line at a position located at an upper part of a chamber formed below the inclined part. 24. The interior surface of the container to which the mixture has been applied, during use,
24. Apparatus according to claim 22 or 23, characterized in that there is a downcomer for a surface located above the chamber and for directing the mixture remaining after the mixture has been applied to the surface to the chamber. 25. The apparatus of claim 24, wherein the level of the mixture remaining after applying the mixture to the surface is maintained in or above a downcomer. 26. The container according to claim 24, wherein the inner surface of the container is shaped so that the mixture remaining after the mixture has been applied to the inner surface is directed to the downcomer by the effect of gravity during use. apparatus. 27. The interior surface of the container comprises a substantially conical or frusto-conical surface, the conical or frusto-conical axis being disposed substantially vertically during use, the cone or frustoconical 27. The device of claim 26, wherein the narrower portion of the cone is located below the wider portion. 28. Apparatus according to claim 22, wherein the container has an outlet for allowing gas released from the mixture to leave the container. 29. An apparatus for separating gas from a hydrate and a three-phase mixture of liquid and gas substantially as described with reference to FIG. 4 of the accompanying drawings. 30. An apparatus for separating gas, liquid and hydrate, comprising a container for receiving an input mixture of gas, liquid and hydrate, filtering means provided in the container, gas, liquid and water. Means for directing the input mixture of the hydrate to the filtering means, thus producing gas for collection or removal from the upper part of the vessel, and liquid being collected or removed from the lower part of the vessel through the filtration means. An apparatus wherein the hydrate is removed and the hydrate is collected by filtration means. 31. The filtering means is a perforated screen, wherein the perforated screen is configured such that hydrates collected by the screen move down the screen and are collected or removed from a container. The device according to claim 30, characterized in that: 32. The screen is curved and the means for directing the mixture against the screen comprises: directing the mixture downward and onto the screen, wherein the hydrate collected by the screen has its kinetic component in an arc. 32. The apparatus according to claim 31, wherein the apparatus is configured to slide off the screen at. 33. The apparatus according to claim 30, wherein the interior of the container is maintained at a high pressure. 34. A gas substantially as described with reference to FIG. 6 in the accompanying drawings,
Equipment for separating liquid and solid hydrates. 35. A hydrate cooling device comprising: a container for receiving an essentially solid or concentrated slurry hydrate; and a gas distribution device configured to supply a fluidizing gas during use. Having a gas distribution device positioned in the vessel to fluidize the hydrate by passing the fluidizing gas through an essentially dry hydrate or concentrated slurry hydrate in the vessel during use. Wherein the hydrate cooling device further comprises means for passing a cooling medium through the fluidized hydrate in the container during use. 36. The apparatus of claim 35, wherein the means for passing the cooling medium through the fluidized hydrate in the vessel is a gas distribution device configured to supply a cooled fluidized gas. . 37. The method of claim 35, wherein the means for passing the cooling medium through the fluidized hydrate is a means for directing a flow of the cooling gas into the fluidized hydrate separately from the fluidized gas. 36. The apparatus according to claim 36. 38. The means for providing a flow of a cooling fluid separated from a fluidizing gas comprises one or more conduits arranged to pass through the fluidized bed through the cooling fluid during use. Item 38. The apparatus according to Item 37. 39. The apparatus of claim 38, wherein the one or more conduits are configured to carry a flow of a cooling fluid substantially consisting of a liquid. 40. The fluidized bed comprises one or more baffles arranged substantially vertically in use to divide the fluidized bed into a number of regions, wherein the hydrate comprises a first hydrate. 40. Apparatus according to any one of claims 35 to 39, wherein the hydrate is received in a region and overflows into the next region when further added. 41. Apparatus according to any one of claims 35 to 40, wherein the gas distribution device is configured to supply a hydrate forming gas. 42. A hydrate cooling device substantially as described with reference to FIG. 8 of the accompanying drawings.