JP2010227810A - Depressurization apparatus for gas hydrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus depressurizing gas hydrates under high pressure to a low pressure, e.g. the atmospheric pressure. <P>SOLUTION: A charging inlet 3a for gas hydrates communicating with a high-pressure atmosphere P1 is formed at a position in the upper wall 3f of a cylindrical body 3, with the position equidistance-shifted from the center of the cylindrical body 3, and a discharging outlet 3b communicating with a low-pressure atmosphere P2 is formed at a position different from that of the charging inlet 3a in the lower wall 3g through the equal-distance shifting. In the cylindrical body 3, a rotary body 2 consisting of two or more gas hydrate receiving chambers 2a arranged concentrically according to the shifts of the charging inlet 3a and the discharging outlet 3b is pivoted. The rotary body 2 is driven by a driving source M arranged externally. The cylindrical body 3 has a sealed liquid supply tube 8 supplying a sealed liquid r into the receiving chambers 2a before gas hydrates are received into the receiving chambers 2a and a depressurization tube 9 making the inside of the receiving chambers 2a communicating with the low pressure atmosphere P2 after gas hydrates h are received into the receiving chambers 2a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus for depressurizing a gas hydrate under high pressure to a low pressure such as atmospheric pressure.

  Gas hydrates that are attracting attention as clean energy include, for example, hydration of raw material gas (methane gas, propane gas, or a mixed gas thereof) and raw water under conditions of 5 to 5.5 MPa and 2 to 4 ° C. Produced by reaction. Moreover, since the produced | generated gas hydrate is in the form of a slurry, it is dehydrated and molded, and formed into a shape such as a pellet to be commercialized.

  By the way, the gas hydrate exhibits the effect called a self-preserving effect when it is minus 20 ° C. under atmospheric pressure, and has a characteristic that it can be stored for a long period of time. When it is stored and transported under a high pressure of 0.5 MPa), it takes a cost to maintain the high pressure state.

  Therefore, a method for depressurizing the generated gas hydrate from a high pressure such as a generation pressure to a low pressure such as atmospheric pressure has been proposed. As an example, a depressurization apparatus that accommodates gas hydrate in a rotating body and depressurizes from a high-pressure atmosphere to a low-pressure atmosphere has been proposed (see, for example, Patent Document 1).

JP 2007-268406 A

  The depressurization device described in Patent Document 1 includes an accommodating process in which a gas hydrate under a high-pressure atmosphere is introduced into a receiving chamber of a rotating body, a depressurizing process for depressurizing the pressure in the receiving chamber to a low-pressure atmosphere, and a receiving chamber. A series of steps consisting of a discharge step of discharging the gas hydrate under a low pressure atmosphere and a pressure increase step of pressurizing the internal pressure of the receiving chamber to a high pressure atmosphere are repeated by rotating the rotating body 360 degrees, so that the batch type Therefore, the gas hydrate is depressurized and is not suitable for mass processing. In addition, in order to perform a large amount of processing, it is necessary to increase the size of the rotating body or to process in a plurality of series, and it is necessary to increase the size of the apparatus and the complexity of the system.

  An object of the present invention is to provide an apparatus capable of depressurizing gas hydrate continuously and in large quantities from a high pressure side to a low pressure side in view of the above-described problems of the prior art.

In order to achieve the above object, the gas hydrate depressurization apparatus according to the present invention is configured as follows.
(1) A gas hydrate inlet 3a that is displaced from the center of the cylindrical body 3 by an equal distance from the center of the cylindrical body 3 and communicates with the high-pressure atmosphere P1 is formed on the upper wall 3f of the cylindrical body 3, and the cylindrical body is formed on the lower wall 3g. 3 is provided with a discharge port 3b for the gas hydrate h which is deviated by an equal distance from the center of the tube 3 and communicated with the low-pressure atmosphere P2 at a position different from the input port 3a, and a plurality of gas hydrates are provided in the cylindrical body 3. The receiving chamber 2a is pivotally supported by a rotating body 2 arranged concentrically in accordance with the displacement of the inlet 3a and outlet 3b, and the rotating body 2 is provided outside the cylindrical main body 3. The cylindrical main body 3 is configured to be driven by a drive source M, and the cylindrical body 3 supplies a sealing liquid r for supplying a sealing liquid r into the receiving chamber 2a before the gas hydrate is received in the receiving chamber 2a. Pipe 8 is connected to the receiving chamber 2a. After hydrate h is accepted, it is characterized in that is provided with a de-pressure pipe 9 which communicates with its receiving chamber 2a and the low pressure atmosphere P2, respectively. (2) The rotating body 2 is characterized in that at least four receiving chambers 2a are arranged on a concentric circle at equal intervals.

Further, the gas hydrate depressurization method according to the present invention is configured as follows in order to achieve the above object.
(3) A depressurization method of depressurizing and transferring the gas hydrate h in the high pressure atmosphere P1 to the low pressure atmosphere P2.
A sealing liquid filling step B1 for supplying the sealing liquid r to the gas hydrate receiving chamber 2, and a gas hydrate supplying step for introducing the gas hydrate h into the receiving chamber 2a filled with the sealing liquid r in the sealing liquid filling step B1. B2, a depressurization step B3 in which the receiving chamber 2a into which the gas hydrate h is introduced in the supply step B2 and the low pressure atmosphere P2 are communicated and depressurized, and the depressurization step B3 is substantially equal to the low pressure atmosphere P2. And a discharge step of discharging the gas hydrate h and the sealing liquid r from the receiving chamber 2a which has become a pressure.
(4) The pressure of the high-pressure atmosphere P1 is 5.0 to 5.5 MPa, and the pressure of the low-pressure atmosphere P2 is 0.1 to 0.4 MPa.
(5) The sealing liquid r is a liquefied gas, liquid propane, hexane, kerosene, or silicon oil that is the same as the raw material gas constituting the gas hydrate h.
(6) The gas hydrate h is a compression-molded molded body, the molded body is spherical or cylindrical, and the size of the molded body is 20 to 100 mm.

  Since the gas hydrate depressurization apparatus of the present invention can simultaneously accept the gas hydrate from the high pressure side and discharge the gas hydrate to the low pressure side, the processing speed is higher than the conventional batch processing type. Will improve.

It is a schematic block diagram of the gas hydrate depressurization apparatus which concerns on this invention. It is a figure which shows the other embodiment of the gas hydrate depressurization apparatus which concerns on this invention. It is a figure which shows the operation | movement of an acceptance chamber, and a pressure change in the gas hydrate depressurization apparatus which concerns on this invention. It is a schematic diagram which shows operation | movement of the rotary body in the gas hydrate depressurization apparatus which concerns on this invention. It is a schematic block diagram of the conventional gas hydrate depressurization apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

For example, as shown in FIG. 1, the depressurization apparatus 1 for a gas hydrate h according to the present invention has a high-pressure atmosphere P1 (for example, 5.0 to 5.5 MPa, which is a generation pressure of gas hydrate), and a temperature of 2. At ˜4 ° C., a hopper 12 is provided in which a molded body h (gas hydrate pellet h) compression-molded into a spherical shape or a cylindrical shape by a compression molding machine (pelletizer) 23 is temporarily stored. The hopper 12 is connected to an inlet 3 a provided in the upper wall 3 f of the cylindrical main body (casing) 3 of the depressurizing device 1, and the gas hydrate pellet h in the hopper 12 is pivoted into the cylindrical main body 3. It is put into the receiving chamber 2a of the supported rotating body 2. The rotating body 2 is formed with a gear 2 d that is driven by a gear 4 a provided in an electric motor M provided outside the cylindrical body 3 around the rotating body 2. And the gas hydrate pellet h is discharged | emitted from the discharge port 3b provided in the lower wall 3g of the cylindrical main body 3. FIG.

  Further, as shown in FIG. 4, the depressurization apparatus 1 supplies the sealing liquid r to the receiving chamber 2a to increase the internal pressure of the receiving chamber 2a to a high pressure P1 (for example, 5.0 to 5.5 MPa). Pressurization step B1, filling step B2 in which the gas hydrate pellet h is charged into the receiving chamber 2a, a depressurizing step B3 in which the inside of the receiving chamber 2a and the low-pressure atmosphere P2 are connected and depressurized, and the depressurized receiving The discharge process B4 for discharging the gas hydrate from the chamber 2a is performed at the same time in each receiving chamber 2a.

  The sealing liquid r is stored in a predetermined amount in the storage tank 21 and exhibits a self-preserving effect when the gas hydrate h becomes the low pressure atmosphere P2, and at a temperature at which the sealing liquid r does not boil in the low pressure atmosphere P2. It is cooled by a refrigerator. In the present embodiment, liquefied propane gas (boiling point is minus 42.1 ° C. at atmospheric pressure) is used as the sealing liquid r, and it is cooled to about minus 50 ° C. In addition to liquefied propane gas, liquid propane, hexane, kerosene, or silicon oil cooled so that the gas hydrate h exhibits a self-preserving effect can be used. These are also preferable as a sealing liquid for the gas hydrate h, like the liquefied propane gas, because of the performance as a cooling medium and the ease of handling.

  The pressure change in the receiving chamber 2a will be described as follows in the order of the pressure increasing process B1, the filling process B2, the depressurizing process B3, and the discharging process B4.

  As shown by reference symbol (a) in FIGS. 4 and 3, the boosting step B1 is performed as shown by reference symbol (b) in the storage chamber 2a in which the gas hydrate h and the sealing liquid r are discharged and the pressure is low pressure atmosphere P2. The sealing liquid r is supplied to the pressure of the high pressure atmosphere P1. Further, the gas hydrate h is cooled to about minus 50 ° C. by the sealing liquid r.

  Next, in the filling step B2, as shown by symbol C in FIGS. 4 and 3, the gas hydrate h inlet 3a communicates with the receiving chamber 2a, and the gas hydrate h in the hopper 12 is supplied to the supply pipe. 5 to the receiving chamber 2a. Since the specific gravity of the gas hydrate h is larger than that of the liquefied propane gas as the sealing liquid r, the gas hydrate h settles in the sealing liquid r and fills the receiving chamber 2a.

  Next, in the depressurization step B3, as shown by reference numeral D in FIGS. 4 and 3, the inside of the receiving chamber 2a filled with the gas hydrate h and the low-pressure atmosphere (in this embodiment, the solid-liquid separator 15). The pressure P1 in the receiving chamber 2a is released by the decompression pipe 9 communicating with the pressure P2, and becomes the pressure P2 of the low pressure atmosphere. When the pressure is released, the gas g (product gas, etc.) adhering to the gas hydrate h is released.

  Then, in the discharge step B4, as shown by the symbol E in FIGS. 4 and 3, the gas hydrate h and the sealing liquid r are removed from the depressurized receiving chamber 2a through the discharge pipe 6 through the solid-liquid separator 15. Drain into. The discharged gas hydrate h and the sealing liquid r are separated by solid-liquid separation means 15a such as punching metal, and the sealing liquid r is returned from the liquid reservoir 15b to the storage tank 21 via the drain 27 and reused. The gas hydrate h is transferred from the outlet 15c to the storage dunk 18 and the like via the pipe 26.

  Such a series of steps B1 to B4 is repeated, and the process of depressurizing the gas hydrate h at the pressure P1 of the high-pressure atmosphere to the pressure P2 of the low-pressure atmosphere is continuously performed.

According to the present invention, the pressurization step, the filling step, the depressurization step, and the discharge step can proceed simultaneously, so that the processing speed is improved as compared with the conventional batch processing type depressurization apparatus.

  As shown in FIG. 2, in order to efficiently fill the gas hydrate pellets h into the supply chamber 2a, the cylinder device 41 forcibly pushes the gas hydrate pellets h with the pushing mechanism 41a. You can also. Moreover, in the said embodiment, although the rotary body 2 was illustrated in the shape of a cylinder for convenience of explanation, it may be a spherical shape. Moreover, you may drive the rotary body 2 directly with drive devices, such as an electric motor.

1 Depressurizing device 2 Rotating body 2a Receiving chamber (through hole)
3 casing 3a inlet 3b outlet 3f upper wall 3g lower wall 4a gear 5 supply pipe 6 discharge pipe 8 sealing liquid supply pipe 9 decompression pipe h hydrate (pellet)
B1 Pressure raising process B2 Filling process B3 Depressurization process B4 Discharge process r Sealing liquid g Gas P1 High pressure P2 Low pressure

Claims (6)

To the upper wall of the cylindrical main body, a gas hydrate inlet that is displaced equidistantly from the center of the cylindrical main body and communicated with the high-pressure atmosphere is deviated equidistantly from the center of the cylindrical main body to the lower wall, In addition, a gas hydrate discharge port communicating with the low-pressure atmosphere is provided at a position different from the input port,
A rotating body in which a plurality of gas hydrate receiving chambers are concentrically arranged in accordance with the displacement of the input port and the discharge port is pivotally supported in the cylindrical main body, and the rotating body has the cylindrical shape. It is configured to be driven by a drive source provided outside the main body,
The cylindrical main body has a sealing liquid supply pipe for supplying a sealing liquid into the receiving chamber before the gas hydrate is received in the receiving chamber, and a receiving chamber after the gas hydrate is received in the receiving chamber. A dehydrating device for gas hydrate, characterized in that a depressurizing pipe is provided for communicating between the gas and the low pressure atmosphere.   2. The gas hydrate depressurization apparatus according to claim 1, wherein at least four receiving chambers of the rotating body are arranged on a concentric circle at equal intervals. A depressurization method of depressurizing and transferring a gas hydrate in a high pressure atmosphere to a low pressure atmosphere,
A sealing liquid filling process for supplying a sealing liquid to the gas hydrate receiving chamber, a gas hydrate supplying process for supplying gas hydrate to the receiving chamber filled with the sealing liquid in the sealing liquid filling process, and a gas in this supplying process A depressurization step of depressurizing the receiving chamber into which the hydrate is introduced and the low-pressure atmosphere, and a gas hydrate and a sealing liquid from the receiving chamber that has become substantially equal in pressure to the low-pressure atmosphere by the depressurization step. A method for depressurizing a gas hydrate comprising a discharging step of discharging.   4. The method for depressurizing a gas hydrate according to claim 3, wherein the pressure of the high pressure atmosphere is 5.0 to 5.5 MPa, and the pressure of the low pressure atmosphere is 0.1 to 0.4 MPa.   4. The gas hydrate depressurization according to claim 3, wherein the sealing liquid is one of a liquefied gas, liquid propane, hexane, kerosene, and silicon oil, which is the same as the raw material gas constituting the gas hydrate. Method.   The gas hydrate according to claim 3, wherein the gas hydrate is a compression-molded molded body, the molded body is spherical or cylindrical, and the size of the molded body is 20 mm to 100 mm. Rate depressurization method.

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