JP4620508B2 - Gravity dehydration type dehydrator - Google Patents

Description

  The present invention relates to a gravity dehydration type dehydrator, more specifically, a gas hydrate produced by reacting a gas and water is introduced into a dehydration tower together with unreacted water, and the dehydration tower is moved upward from below. And a gravity dehydration-type dehydration apparatus that causes unreacted water to flow out of the tower from the filtration section provided on the side wall surface of the dehydration tower.

  As a method of storing and transporting natural gas mainly composed of hydrocarbons such as methane, a method of storing and transporting LNG by cooling natural gas to a liquefaction temperature to form LNG (liquefied natural gas) is common. is there.

  However, in order to liquefy methane, which is the main component of LNG, an extremely low temperature of −162 ° C. is necessary. In order to store and transport these strict conditions, dedicated storage facilities and LNG ships are required. Necessary.

  The manufacture and maintenance of such devices are very expensive, and low cost storage and transport methods have been investigated as an alternative to the above methods.

  As a result of such research, a method for storing and transporting this gas hydrate was discovered, which produced a solid-state hydrate (hereinafter referred to as gas hydrate) by reacting natural gas with water. ing.

  In this method, not only the ultra-low temperature condition as in the case of handling LNG is required, but also the handling is relatively easy because the gas hydrate is solid.

  Gas hydrate is a kind of clathrate compound (clathrate compound), and each component of natural gas is formed in a three-dimensional cage clathrate formed by multiple water molecules. Molecules, that is, methane, ethane, propane, etc. enter and form an inclusion crystal structure. For example, under a condition where hydrates of methane can exist stably, that is, at −30 ° C. and at atmospheric pressure, the volume is about 1/170 compared to the case of gas.

  Thus, the gas hydrate can be produced under temperature and pressure conditions that are relatively easily obtained, and can be stably stored.

In order to industrialize the production of this gas hydrate and produce it in large quantities, a method for producing gas hydrate by blowing natural gas into water (a bubbling method) (see, for example, Patent Document 1), or in the gas phase There is a method for producing gas hydrate by spraying water (spray method) (for example, see Patent Document 2).
JP 2003-80056 A JP 2003-105362 A

  However, in any case, since the gas hydrate immediately after production is in a slurry state containing unreacted water, if it is stored and transported as it is or after being frozen and stored in ice, There is a problem that extra costs are required.

  In order to avoid such a problem, the slurry gas hydrate is dehydrated to increase the concentration of the gas hydrate. As in the invention of Patent Document 2, a screw press type dehydrator is used. When using and dehydrating forcibly, it is inevitable that solid particles of gas hydrate are mixed in the filtrate after dehydration. For this reason, there exists a problem that the recovery rate of gas hydrate falls.

  Therefore, the present inventors have considered a gravity dehydration type dehydrator using gravity as shown in FIG. The gas hydrate manufacturing apparatus including this dehydrating apparatus has the following structure.

  That is, the water w and the natural gas g that is the raw material gas are supplied to the first generator 1 to generate a gas hydrate (not shown) that is a hydrate of the natural gas g and the water w. At that time, the inside of the first generator 1 is stirred by the stirrer 2 so as to be a low-concentration slurry s.

  At that time, the heat transfer tube 3 is provided in the first generator 1, or a cooling jacket (not shown) is provided outside the first generator 1 to cool the inside of the first generator 1.

  The low concentration gas hydrate slurry s produced in the first generator 1 is supplied to the bottom of the cylindrical dehydration tower 5 by the slurry supply pump 4. The dehydration tower 5 is provided with a liquid removal filter 7 made of a metal mesh or a porous sintered plate on the side wall surface. A drainage jacket 8 is provided outside the filter body 7.

  Water (unreacted water) w flowing out from the filter body 7 to the outside of the dehydration tower 5 is returned to the first generator 1 by the circulating water pump 9, while being cooled to a predetermined temperature by the circulating water cooler 10. The The unreacted gas g flowing into the drainage jacket 8 is returned to the first generator 1 by the circulating gas blower 11.

  The gas hydrate a dehydrated by the dehydration tower 5 and having a reduced water content is supplied to a second generator (not shown) by a conveying device 12 such as a screw feeder provided at the upper end of the dehydration tower 5, Dehydration is performed using a sum reaction. As the production of gas hydrate proceeds, the first generator 1 is replenished with water w by the pump 13 and replenished with natural gas g by the raw material gas compressor 14.

  By the way, when this gas hydrate production apparatus is enlarged and mass production of gas hydrate is attempted, the conventional cylindrical dehydration tower 5 has a large diameter and height. When the height of the dehydration tower 5 increases, the pump head of the slurry supply pump 4 becomes higher, and there is a problem that the power consumption increases.

On the other hand, regarding the diameter D of the dehydration tower 5, for example, assuming a 2.4 T / D plant, the cross-sectional area A of the dehydration tower 5 is about 116.11 (m ² ), and the diameter D of the dehydration tower 5 is The size is about 12 (m).

  As described above, when the diameter D of the dehydration tower 5 increases, the thickness of the deposition layer of the gas hydrate a deposited on the inner surface of the filter body 7 provided in the dehydration tower 5 becomes very thick. There is a problem that the water of part C is difficult to drain (see FIG. 5).

  The present invention has been made to solve such problems, and the object of the present invention is to maintain the level of throughput of the dehydration tower while maintaining the level of throughput of the conventional dehydration tower. The purpose is to reduce the construction cost and running cost by suppressing the height of the tube.

  In order to achieve this object, the present invention is configured as follows.

The gravity dehydration type dehydrator according to claim 1 supplies a slurry-like gas hydrate formed by the reaction of gas and water to a dehydration tower and raises it from below to above. In a gravity dehydration type dehydration apparatus for allowing reaction water to flow out from a filter body provided on a side wall surface of a dehydration tower, the dehydration tower has a double cylindrical structure comprising two cylinders of an inner cylinder and an outer cylinder And a slurry supply pipe for supplying gas hydrate slurry between the inner cylinder and the outer cylinder at the lower part of the dehydration tower, and dehydration on both side walls of the inner cylinder and the outer cylinder, respectively. The filter body is provided, and unreacted water is allowed to flow out of the tower through two filter bodies, a filter body provided in the inner cylinder and a filter body provided in the outer cylinder.

Gravity dewatering type dewatering apparatus according to claim 2, a slurry gas hydrate gas and water were Deki reacted, raised upwardly from the lower side is supplied to the dehydration column, while the increase in the dehydration device gravity dewatering type to flow out the tower from the filter body provided with a water unreacted side wall surface of the dehydration column, the pressure vessel, a double tube having a filter body for each dewatering both the inside and the outside wall provided dehydration tower in the form structures, further provided with a gas hydrate-on portion of the tubular to dehydration Tatsuchu central in the cavity, the breakdown voltage and the gas hydrate loading portion wherein the during the dehydration tower and the dehydration tower A waste tank is provided between the containers, and a scraper is provided above the dehydration tower to scrape off the gas hydrate at the upper end opening of the dehydration tower into the gas hydrate input section, and the gas hydrate pulverizer in the gas hydrate input section And providing Serial only set the gas hydrate discharging unit below the gas hydrate loading portion, in a further, the slurry supply tube provided in the lower portion of the dehydration column, and, which is characterized in that a drain pipe to the drain tank It is.

Gravity dewatering type dewatering apparatus according to claim 3 is characterized in providing said gas hydrate grinding device and the scraper on a common rotary shaft.

Dehydrating apparatus gravity dewatering formula according to claim 4, as the gas hydrate discharging unit, it is characterized in applying a screw feeder.

As described above, the invention according to claim 1 introduces the gas hydrate produced by reacting gas and water into the dehydration tower together with unreacted water, and from above to below the dehydration tower. Gravity dehydration type dehydration device that raises the unreacted water to the outside of the tower from the filtration section provided on the side wall surface of the dehydration tower during the ascent, wherein the dehydration tower comprises an inner cylinder and an outer cylinder. A double-tubular dehydration tower comprising two cylinders, and a filter for dehydration provided on both side walls of the inner cylinder and the outer cylinder, respectively, and unreacted water provided in the inner cylinder. The cross-sectional area A of the dehydrating tower of the present invention is the same as the cross-sectional area A of the conventional cylindrical dehydrating tower. also, the present invention, the distance W between the inner and outer cylinder of the dewatering tower is (D ₀ -D ₁₎ / 2, and the inside and outside both the dehydration column as compared with the conventional Distance W between is significantly reduced (see Fig. 2.).

For example, when a 2.4 T / D plant is assumed and the outer cylinder diameter D ₀ is assumed to be 14.04 (m), the inner cylinder diameter D ₁ becomes 7.02 (m), and the dehydration tower The distance W (= (D ₀ −D ₁ ) / 2) between the inner and outer cylinders is about 3.5 (m).

  Therefore, while the diameter D of the conventional cylindrical dehydration tower is about 12 (m), the double cylindrical structure dehydration tower of the present invention has a gap W between the inner cylinder and the outer cylinder. Since it was about 3.5 (m), the dehydration tower having the double cylindrical structure of the present invention can be dehydrated more smoothly than the conventional cylindrical dehydration tower.

  As a result, it is possible to reduce the construction cost, running cost, etc., while suppressing the height of the column of the dehydration tower while maintaining the processing amount of the dehydration tower at the level of the conventional dewatering tower. It became.

  The invention according to claim 2 introduces gas hydrate produced by reacting gas and water into a dehydration tower together with unreacted water, and raises the dehydration tower upward from below. A gravitational dehydration type dehydration device for allowing unreacted water to flow out from a filtration unit provided on the side wall surface of the dehydration tower during the ascending operation, wherein the dehydration filter is provided in the pressure vessel and on both inner and outer wall surfaces. A dehydrating tower having a double cylindrical structure is provided, and a cylindrical gas hydrate charging section is provided in the central cavity of the dehydrating tower, and the gas hydrate charging section and the pressure vessel are disposed between A drainage tank is formed, and further, a pulverizing device for gas hydrate pulverization is provided in the gas hydrate input part, and a gas hydrate discharge device is provided below the gas hydrate input part, above the dehydration tower. A scraper is rotatably provided, and Since a slurry supply pipe is provided below the water tower and a drain pipe is provided in the drain tank, in addition to the effects already described, a scraper above the dehydration tower and a gas hydrate discharge device below the gas hydrate input section Can be used to smoothly feed the dehydrated gas hydrate.

  In the invention according to claim 3, since the pulverizing apparatus and the scraper are attached to a common rotating shaft, the number of parts can be reduced.

  In the invention according to claim 4, since a screw feeder is applied as the gas hydrate discharge device, the dehydrated gas hydrate can be smoothly transferred.

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

  FIG. 1 is a cross-sectional view of a gravity dehydration type dehydrator according to the present invention. 2 is a cross-sectional view taken along line XX of FIG. 1, and FIG. 3 is a cross-sectional view taken along line YY of FIG.

In FIG. 1, reference numeral 20 denotes a gravity dehydration type dehydrator, which includes a dehydration tower 22 in a pressure vessel (also referred to as a pressure shell) 21. As shown in FIG. 2, the dehydrating tower 22 has a double cylindrical structure formed by an inner cylinder 23 having a diameter D ₁ and an outer cylinder 24 having a larger diameter D ₀ .

  The upper end of the inner cylinder 23 is slightly lower than the upper end of the outer cylinder 24, and the upper end opening 25 of the dewatering tower 22 has an inverted truncated cone shape.

  Further, as shown in FIG. 1, the dehydration tower 22 is provided with filter bodies 26a and 26b for dehydration at a predetermined height. That is, the inner cylinder 23 is provided with an annular liquid removal filter body 26a formed of a wire mesh, a porous sintered plate, or the like at a predetermined height. Further, the outer cylinder 24 is provided with a liquid removal filter body 26b formed by the same method as that of the filter body 26a at the same height as the filter body 26a.

  The dehydration tower 22 is provided with a cylindrical gas hydrate charging part 28 in a central cavity 27, and a drain tank 29 is formed between the gas hydrate charging part 28 and the pressure vessel 21. The drainage tank 29 has an annular bottom plate 30. In addition, the gap between the outer cylinder 24 of the dehydration tower and the pressure vessel 21 is closed by an annular shielding plate 31.

  Further, the dehydration tower 22 is provided with a pulverizing device 32 for gas hydrate pulverization in a gas hydrate charging section 28. The crusher 32 is formed by a plurality of flat blades 34 provided radially at the lower end of a vertical rotating shaft 33 that penetrates the upper portion of the pressure vessel 21 (see FIG. 2).

  The crusher 32 is not limited to a flat blade, and may be a rod, for example. In short, any material that can finely pulverize the mass of the gas hydrate may be used. The rotating shaft 33 is rotated by a motor 35.

  A gas hydrate discharge device 36 is provided below the cylindrical gas hydrate input portion 28. The gas hydrate discharge device 36 is formed by providing a plurality of (for example, two) screw feeders 37 in parallel. In addition, as long as it can discharge | emit smoothly the gas hydrate after dehydration, things other than a screw feeder may be used.

  A scraper 38 is provided above the dehydration tower 22. The scraper 38 is formed by providing three spatulas or blades 39 radially on the rotating shaft 33 (see FIG. 2). However, as long as the dehydrated gas hydrate can be scraped off from the dehydration tower 22, it may be other than a spatula or a blade.

  Further, a slurry supply pipe 40 is provided at the lower part of the dehydration tower 22 in the tangential direction of the dehydration tower 22, and the gas hydrate slurry s supplied from the slurry supply pipe 40 to the lower part of the dehydration tower 22 passes through the dehydration tower 22. It is designed to turn.

  Further, a drain pipe 41 is provided in the drain tank 29, and dehydrated unreacted water (also referred to as brine) w is returned to a generator (not shown). Further, the pressure vessel 21 is provided with a pipe 42 to return the unreacted natural gas g in the pressure vessel 21 to a first regenerator (not shown).

Here, assuming that the diameter of the outer cylinder 24 is D ₀ , the diameter of the inner cylinder 23 is D ₁ , and the cross-sectional area of the dehydrating tower 22 is A, the diameter D ₁ of the inner cylinder 23 is as follows.

That is,
_{D 1 = 2√ ((D 0} /2) 2 - (A / π))

Therefore, for example, assuming a 2.4 T / D plant, the diameter D ₀ of the outer cylinder 24 is 14.04 (m), and the cross-sectional area A of the dehydration tower 22 is the cross-sectional area of a conventional cylindrical dehydration tower. As in the case of 116.11 (m ² ), the diameter D ₁ of the inner cylinder 23 is 7.02 (m), and the interval W between the inner and outer cylinders of the dehydration tower 22 (= (D ₀ −D ₁ ) / 2) is about 3.5 (m).

  Next, the operation of this dehydrator will be described.

As shown in FIG. 1, when supplying the gas hydrate slurry s from the slurry supply pipe 40 to the dehydration column 22 of a double cylindrical structure, this gas hydrate slurry s, as shown in FIG. 3, the dehydration tower 22 As it turns, the space between the inner cylinder 23 and the outer cylinder 24 rises from below to above.

  And when it reaches the position of the annular filter body 26a provided in the inner cylinder 23 of the dehydration tower 22 and the annular filter body 26b provided in the outer cylinder 24, the unreacted contained in the gas hydrate slurry s. The water w passes through the filter bodies 26a and 26b and is discharged out of the tower.

  That is, the unreacted water w discharged from the filter body 26 a attached to the inner cylinder 23 flows down to the drainage tank 29 along the wall surface of the inner cylinder 23, and the unreacted water w discharged from the filter body 26 b attached to the outer cylinder 24. The reaction water w flows down to the drainage tank 29 along the wall surface of the outer cylinder 24.

  The gas hydrate a dehydrated while passing through the filter bodies 26a and 26b of the dehydrating tower 22 and having a water content of about 40 to 50% is sequentially pushed upward. Then, when reaching the upper opening 25 of the dehydration tower 22, the scraper 38 scrapes off into the cylindrical gas hydrate charging section 28 provided at the center of the dehydration tower 22.

  The mass of the gas hydrate a scraped into the gas hydrate input unit 28 is finely pulverized by a pulverizer 32 provided in the gas hydrate input unit 28 and falls to the lower part of the gas hydrate input unit 28.

  The gas hydrate a dropped to the lower portion of the gas hydrate charging unit 28 is transported to the next process, for example, the second generator by the biaxial screw feeder 37.

  On the other hand, the unreacted water w flowing down to the drainage tank 29 is returned to the first generator (not shown) via the drainage pipe 41. Further, the natural gas g in the upper space of the pressure vessel 21 is returned to the first generator via the pipe 42.

1 is a cross-sectional view of a gravity dehydration type dehydrator according to the present invention. 2 is a cross-sectional view taken along line XX of FIG. 3 is a cross-sectional view taken along line YY of FIG. It is a block diagram of the conventional gas hydrate production | generation apparatus. It is principal part expansion explanatory drawing of a dehydration tower.

Explanation of symbols

a gas hydrate g gas w water 5 dehydration tower 7 filtration part 22 dehydration tower of double cylinder structure 23 inner cylinder 24 outer cylinder 26a, 26b filter for dehydration

Claims (4)

A slurry gas hydrate formed by the reaction of gas and water is supplied to the dehydration tower and raised upward from below, and during this rise, unreacted water is provided on the side wall of the dehydration tower. In the gravity dehydration type dewatering apparatus that flows out from the body to the outside of the tower, the dewatering tower has a double cylindrical structure composed of two cylinders of an inner cylinder and an outer cylinder , A slurry supply pipe for supplying gas hydrate slurry is provided between the cylinder and the outer cylinder , and filter bodies for dehydration are provided on both side wall surfaces of the inner cylinder and the outer cylinder, respectively, and unreacted water is supplied. A gravity dehydration-type dehydrating apparatus, characterized in that the dehydrating apparatus is made to flow out of a tower through two filter bodies, a filter body provided in an inner cylinder and a filter body provided in an outer cylinder. A slurry gas hydrate gas and water were Deki reacted, raised upwardly from the lower side is supplied to the dehydration column, provided with a water unreacted during the rise to the side wall surface of the dehydration tower In the gravity dehydration type dewatering device that flows out of the tower from the filter body ,
The pressure vessel, the dehydration column of the double cylindrical structure in which filtration bodies for each dewatering both the inside and the outside wall surface is provided, further, the gas hydrate loading portion of the tubular disposed in dehydration Tatsuchu central in the cavity A drainage tank is provided between the gas hydrate input part and the dehydration tower and between the dehydration tower and the pressure vessel, and the gas hydrate at the upper end opening of the dehydration tower is disposed above the dehydration tower. the scraper to scrape off the closing portion provided, the the gas hydrate turned portion provided with a gas hydrate crusher, the only set the gas hydrate discharging unit below the gas hydrate loading portion, further, the said dehydration tower A gravity dehydration type dewatering apparatus, wherein a slurry supply pipe is provided at a lower portion , and a drain pipe is provided in the drainage tank. The gravity dehydration type dehydrator according to claim 2, wherein the gas hydrate crusher and the scraper are provided on a common rotating shaft.   The gravity dehydration type dehydrating apparatus according to claim 2, wherein a screw feeder is applied as the gas hydrate discharging apparatus.

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