JP4854364B2 - Gas hydrate production equipment - Google Patents

Description

  The present invention relates to a gas hydrate production apparatus for producing a gas hydrate by reacting a raw material gas such as natural gas with water.

A gas hydrate is an ice-like solid crystal formed by water molecules and gas molecules, and clathrate hydrates (hydrides) in which gas molecules intervene inside the cage of a three-dimensional structure constructed by water molecules. (Rate) is a general term. Since gas hydrate contains about 165 Nm ^{3 of} natural gas in 1 m ³ of gas hydrate, research and development is actively conducted as a means for transporting and storing natural gas.

  As a device for producing gas hydrate, conventionally, a bubbling method in which a raw material gas is blown into raw water in a generator (see, for example, Patent Document 1), and raw water is sprayed into a generator filled with raw material gas. Spraying system (for example, refer to Patent Document 2), reaction line system (for example, refer to Patent Document 3) using a line mixer and a water tube type reaction conduit.

  However, the bubbling method introduces a generator with a stirrer, an external cooler that removes generated heat (also called reaction heat), and a gas hydrate slurry generated by the generator to remove unreacted water from gravity. Since it is equipped with a gravity dehydrator (also called a gravity dehydration tower) that uses and dehydrates, (1) a stirrer is required, (2) two devices, a generator and an external cooler, are required ( 3) The dehydrator is large due to gravity dehydration, and (4) the dehydrator is difficult to control due to gravity dehydration.

  In addition, as described above, since the spray method sprays water from the nozzle into the generator filled with the raw material gas, (1) the production rate of the gas hydrate is slow, (2) the raw material gas in the generator is Since it was cooled by an external cooler, there were problems such as poor heat transfer.

On the other hand, the pipe system has problems such as (1) a long reaction pipe line and (2) a long pressure line, resulting in a large pressure loss.
JP 2003-80056 A JP 2002-38171 A JP 2002-356665 A

  The present invention does not require a stirrer for the generator and is simple in the apparatus, and moreover, it is easy to control the dehydrator and can make the gas hydrate conversion rate of the product constant. Is to provide.

According to the first aspect of the present invention , a shell and tube type generator is provided on the downstream side of an ejector-type mixer that stirs and mixes a raw material gas and raw material water, and a cone is provided on the downstream side of the shell and tube type generator. In a gas hydrate manufacturing apparatus provided with a dehydrator having a filter-like filter body, a part of the gas hydrate slurry generated by the shell and tube type generator is returned to the shell and tube type generator. Further, an NGH conversion rate meter is provided on the downstream side of the dehydrator, and a flow rate adjusting valve provided in a drain pipe of the dehydrator is controlled by the NGH conversion rate meter .

According to a second aspect of the present invention, the shell-and-tube generator includes end plates before and after the body, the front first end plate includes a plurality of partition walls therein, and the rear second end plate includes A partition having a vertical partition in the center and a partition corresponding to an odd-numbered partition provided on the first end plate is provided on the left side of the vertical partition, and an even number provided on the first end plate on the right side of the vertical partition. provided a partition wall corresponding to stages of the partition wall, and characterized in that a corner portion having a wetted surface of the lordosis song like the junction between the end plate and the partition wall.

The invention according to claim 3, the pre-Symbol ejector-type mixer, thin to constricted body portion, a first collision body provided radially triangular or trapezoidal penetrating portions in a plate-like substrate, a plate-like A second collision body provided with a star-shaped through portion is alternately provided on the substrate.

  As described above, the invention according to claim 1 stirs and mixes the raw material gas and the raw water with the ejector-type mixer, so that a stirrer or a motor for driving the stirrer in the generator becomes unnecessary, and the structure is It becomes simple and the electric power which operates a motor becomes unnecessary.

  In addition, the present invention is provided with a shell and tube type generator on the downstream side of the ejector type mixer, and also provided with a partition wall for U-turning the gas hydrate slurry in the end plates at the front and rear ends of the generator. Compared with the conventional reaction line system consisting of a plurality of bent pipes, the generator is more compact and pressure loss of the generator can be suppressed. Moreover, since this generator is a shell and tube type, it is possible to efficiently remove reaction heat generated during the generation of the gas hydrate, and thus to efficiently generate the gas hydrate.

  Furthermore, the present invention is provided with a dehydrator having a cone-shaped filter body on the downstream side of the generator, and a flow control valve is provided in the drain pipe of the dehydrator, so that the control of the dehydrator becomes easy. It has become possible to control the gas hydrate conversion rate (hereinafter referred to as NHG conversion rate) of the product gas hydrate.

According to the second aspect of the present invention, since the corner portion having the curved wetted surface is provided at the joint portion between the end plate and the partition wall, the flow rate of the gas hydrate slurry in the end plate can be made uniform. It became.

According to a third aspect of the present invention, there is provided a first impingement body in which triangular or trapezoidal through portions are radially provided on a plate-like substrate in a thinly wound barrel portion of the ejector-type mixer; Since the second collision body provided with the star-shaped through-holes on the substrate is alternately provided, the raw water is vigorously stirred by the first and second collision bodies, and the raw material gas is entrained therein to form a group of fine bubbles. The raw water and the raw material gas are mixed. As a result, the contact area between the source gas and the source water is increased, and the source gas is efficiently dissolved in the source water.

As in the first aspect of the invention, when a part of the gas hydrate slurry generated in the generator is returned to the generator and recirculated, the core of the gas hydrate is contained in the gas hydrate slurry. As it exists, the degree of supercooling is unnecessary and the gas hydrate is generated according to the operating temperature. On the other hand, when not circulating, the mixture of water and gas exiting the mixer enters the shell and tube heat exchanger and is cooled, but until the region where the degree of supercooling becomes a certain size (4-8 ° C) Hydrate is not generated. Further, when the degree of supercooling is reached, hydrate is rapidly generated, and the temperature drops to the temperature of steady operation. Thus, when hydrate is generated abruptly, the inside of the pipe may be closed by hydrate. Further, in the supercooling section, the heat transfer heat amount is reduced, so that the apparatus becomes large.

First, the first embodiment will be described, and then the second embodiment will be described.
(1) First Embodiment As shown in FIG. 1, the gas hydrate production apparatus of the present invention comprises an ejector type mixer 1, a shell and tube type gas hydrate generator 2, and a dehydrator 3. has the the mixer 1, the raw material gas supply pipe 4 and the raw material water supply pipe 5 is connected. The mixer 1 and the gas hydrate generator 2 are connected by a pipe 6, and the gas hydrate generator 2 and the dehydrator 3 are connected by a slurry supply pipe 8 having a slurry pump 7. The slurry supply pipe 8 positioned between the slurry pump 7 and the dehydrator 3 is branched from the branch point a, and a part of the slurry is injected into the pipe 6 by the branch pipe 16. Here, the circulating slurry amount may be about 0 to 10%. An NGH conversion meter 10 is provided in the gas hydrate discharge pipe 9 provided at the outlet of the dehydrator 3. A drainage pipe 11 connecting the dehydrator 3 and the raw material water supply pipe 5 is provided with a flow rate adjusting valve 12 and a pump 13, and an unreacted gas recovery pipe 14 connecting the dehydrator 3 and the raw material gas supply pipe 4 is provided. A compressor 15 is provided. Here, the flow rate adjusting valve 12 is controlled by the NGH conversion rate meter 10. As the NGH conversion rate meter, for example, a mixed phase fluid mixing rate measuring device (Japanese Patent Laid-Open No. Sho 62-172253) can be applied.

  As shown in FIG. 2, the ejector-type mixer 1 includes a tube body 21 having a narrowed barrel portion 20, and a nozzle tip 22 positioned upstream of the barrel portion 20 and bent in an L shape. Is formed by a nozzle 23 positioned at the entrance of the body 20. Here, the raw material water supply pipe 5 is connected to the upstream end of the pipe body 21, the pipe 6 is connected to the downstream end of the pipe body 21, and the raw material gas supply pipe 4 is connected to the nozzle 23. It has become.

  By the way, the ejector-type mixer shown in FIG. 2 can be used. However, as shown in FIG. 3, the first collision body 25 and the second collision body 26 are alternately provided on the thinly-rolled barrel portion 20. Mixing of gas and raw water can be further promoted. As shown in FIG. 4A, the first collision body 25 is a circular substrate 27 provided with triangular or trapezoidal through-holes 28 radially. The second collision body 26 is shown in FIG. As shown in b), a star-shaped through portion 30 is provided on a circular substrate 29. At that time, the first collision body 25 and the second collision body 26 are set so that one of them is slightly rotated clockwise or counterclockwise so that the through portions 28 and 30 do not overlap.

  As shown in FIG. 5, the shell-and-tube type gas hydrate generator 2 has a trunk portion 32 containing a large number of pipes 31, and both ends of the pipe 31 are sealed at both ends of the trunk section 32. The tube plates 33 and 33 are penetrated. The trunk portion 32 has partition plates 34 alternately on the ceiling portion and the bottom portion thereof, and the refrigerant liquid flowing in from the refrigerant inflow portion 35 moves while meandering and is discharged from the refrigerant outflow portion 36. .

  As shown in FIG. 5, the gas hydrate generator 2 includes a first end plate 37 at the front end (upstream portion) of the body portion 32, and a second end plate at the rear end portion (downstream portion) of the body portion 32. 38. The first end plate 37 has a workpiece inflow portion 39 at the bottom, and the second end plate 38 has a workpiece outflow portion 40 at the top. As shown in FIG. 6A, the first end plate 37 has a plurality of (for example, five) partition walls 41 provided horizontally therein to form a plurality of (for example, ten) partitions A to J. is doing. In this example, the sections B to C, the sections D to E, the sections F to G, and the sections H to I that are in the left-right relationship are in communication with each other. On the other hand, as shown in FIG. 6B, the second end plate 38 is provided with a vertical partition wall 42 extending from the section A ′ to the section J ′ at the center, and between the sections A ′ and C ′, and the sections D ′, Partition walls 43 are provided between G ′, between sections H ′ and J ′, between sections B ′ and E ′, and between sections F ′ and I ′.

  Here, as shown in FIG. 7, a corner portion 45 having a curved wetting surface 44 is formed at the joint portion between the first end plate 37 and the partition wall 41 and at the joint portion between the second end plate 38 and the partition walls 42 and 43. Established so that no dead water area occurs.

  As shown in FIG. 1, the dehydrator 3 includes a pressure-resistant container 47 in which a cone-shaped (truncated cone-shaped) filter body 48 is provided substantially horizontally, and the filter body 48 is meshed. . The drain pipe 11 is connected to the bottom of the pressure vessel 47, while the unreacted gas recovery pipe 14 is connected to the top of the pressure vessel 47. If desired, a cone-type screw (not shown) may be provided in the filter body 48 to increase the thrust of the gas hydrate slurry. Further, the dehydrator 3 may be one in which the filter body 48 is provided in a vertical shape.

  Next, the operation of the gas hydrate manufacturing apparatus will be described.

  As shown in FIG. 2, the raw material water w cooled to a predetermined temperature (for example, 4 to 8 ° C.) is supplied to the tube body 21 of the mixer 1, and a predetermined pressure (for example, 4 to 5.5 MPa) is applied. When the pressurized source gas g is supplied to the nozzle 23 of the mixer 1, the flow velocity rapidly increases in the narrowed barrel portion 20 of the tube body 21, so that the source gas g becomes fine bubbles and the source water w And mix evenly.

  As shown in FIG. 1, the mixed water w ′ mixed with the raw material gas is supplied through the pipe 6 to the workpiece inflow portion 39 of the shell and tube type gas hydrate generator 2. As shown in FIG. 5, the mixed water w ′ supplied to the workpiece inflow portion 39 of the shell-and-tube type gas hydrate generator 2 is divided into a partition wall 41 in the first end plate 37 and a partition wall in the second end plate 38. A U-turn is made along the lines 42 and 43 and the inside of the body portion 32 is meandered many times. And finally, although discharged | emitted from the to-be-processed outflow part 40, the raw material gas g and the raw material water w react in the meantime, and it becomes the gas hydrate slurry s.

  Here, the flow of the mixed water w ′ in the first end plate 37 and the second end plate 38 will be described. In the first end plate 37, as shown in FIG. E, the section F flows to the section G, the section H to the section I, and in the second end plate 38, as shown in FIG. 6B, the section A ′ to the section B ′, the section C ′ to the section D ′, and the section E It flows from 'to section F', from section G 'to section H', and from section I 'to section J'.

  The gas hydrate slurry s (NGH conversion rate: 20 to 30%) generated by the gas hydrate generator 2 is supplied to the dehydrator 3 by a slurry pump 7 as shown in FIG. The gas hydrate slurry s supplied to the dehydrator 3 is pressure-dehydrated by the thrust of the slurry pump 7 because the filter body 48 is formed in a cone shape, and has a NGH conversion rate of about 40 to 60%. Hydrate n. Unreacted water w ″ dehydrated by the dehydrator 2 is returned to the raw water supply pipe 5 by the pump 13. At this time, the flow rate adjusting valve 12 is set by the NGH conversion rate meter 10 provided in the gas hydrate discharge pipe 9. By adjusting, the NGH conversion rate can be controlled.On the other hand, the unreacted gas g ″ accumulated in the dehydrator 3 is returned to the source gas supply pipe 4 through the unreacted gas recovery pipe 14.

It is a schematic block diagram of the gas hydrate manufacturing apparatus which concerns on this invention. It is sectional drawing of a mixer. It is sectional drawing of a mixer. (A) The front view of a 1st collision body, (b) The front view of a 2nd collision body. It is a side view including the partial cross section of a generator. (A) XX sectional drawing of FIG. 5, (b) YY sectional drawing of FIG. It is sectional drawing of an end plate.

Explanation of symbols

g Raw gas s Gas hydrate slurry w Raw water 1 Ejector type mixer 2 Shell and tube type generator 3 Dehydrator 11 Drain pipe 12 Flow rate adjusting valve 37, 38 End plate 41, 42, 43 Partition 48 Filter

Claims (3)

A dehydrator having a shell-and-tube generator provided downstream of an ejector-type mixer for stirring and mixing the raw material gas and raw water, and having a cone-shaped filter body downstream of the shell-and-tube generator. In the gas hydrate manufacturing apparatus provided, a part of the gas hydrate slurry generated by the shell and tube type generator is returned to the shell and tube type generator and recirculated, and the dehydrator An apparatus for producing gas hydrate , comprising an NGH conversion rate meter downstream of the first flow rate control device, and a flow rate adjusting valve provided in a drain pipe of the dehydrator is controlled by the NGH conversion rate meter . The shell-and-tube generator includes end plates before and after the body, the front first end plate includes a plurality of partition walls therein, and the rear second end plate includes a partition wall perpendicular to the center thereof. A partition corresponding to an odd-numbered partition provided on the first end plate is provided on the left side of the vertical partition, and a partition corresponding to an even-numbered partition provided on the first end plate is provided on the right side of the vertical partition. The gas hydrate manufacturing apparatus according to claim 1 , wherein a corner portion having a curved wetting surface is provided at a joint portion between the end plate and the partition wall . The ejector-type mixer includes a first colliding body in which triangular or trapezoidal through portions are radially provided in a plate-like substrate in a thinly wound barrel, and a star-like through portion in a plate-like substrate. the provision provided with a second impactor alternately gas hydrate production apparatus according to claim 1, wherein.

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