JP4463233B2 - Gravity dehydration apparatus, gravity dehydration method, and gas hydrate manufacturing apparatus - Google Patents

Description

  The present invention feeds a slurry such as a gas hydrate slurry from the lower part to a vertically long dehydration tower, discharges water in the slurry from a drain outlet provided in the middle of the dehydration tower, and removes the solid content in the slurry. Gravity dewatering device configured to move and separate water by gravity from the bed moved above the drainage port by moving the bed formed at a predetermined height above the drainage port. The invention relates to a gravity dehydration method and a gas hydrate manufacturing apparatus.

  In gas hydrate, gas molecules such as hydrocarbons such as methane, ethane, propane, and butane, which are natural gas components, and carbon dioxide are taken into the interior of the three-dimensional structure formed by combining water molecules. It is a general term for clathrate hydrates (hydrates) formed in this way. In other words, gas hydrate is an ice-like solid substance composed of source gas molecules and water molecules, and is a kind of stable inclusion compound in which source gas molecules are included inside a three-dimensional cage structure formed by water molecules. It is. This gas hydrate has a relatively large gas storage capacity, and has characteristic properties such as large generation / decomposition energy and selectivity of hydrated gas. For example, transportation and storage of natural gas, etc. Various applications such as means, heat storage systems, actuators, and separation and recovery of specific component gases are possible, and research is actively conducted.

  Gas hydrate is usually generated under high pressure and low temperature conditions. The following methods are well known as generation methods. By spraying cooled water from the top of the reaction vessel filled with raw material gas at high pressure, so-called "water spray method", in which gas hydrate is generated on the surface of the water droplet when the water droplet falls in the raw material gas, reaction A so-called “bubbling method” or the like is performed such that gas hydrate is generated on the surface of the bubbles when the bubbles of the source gas rise in the water by introducing the source gas into the water in the container as bubbles.

  In the bubbling method, the gas hydrate generated in the water in the reaction vessel floats in the water because the specific gravity is smaller than that of water. Then, the amount of gas hydrate increases with the progress of the production reaction and is slurried by stirring. Usually, when the gas hydrate content in the slurry reaches about 20 wt%, the generated gas hydrate is extracted out of the reaction vessel in a slurry state.

  The extracted gas hydrate in the slurry state is passed through a dehydrator to be dehydrated, and the gas hydrate content is increased to about 50 wt%. In this state, it is sent to the next generation step for further increasing the gas hydrate content to about 90 wt%.

  One of the dehydrating apparatuses is a gravity dehydrating apparatus (for example, Patent Document 1), which is effective for dehydrating gas hydrate and is being improved. A conventional gravity dehydrator is provided with a slurry introduction part at the bottom, a drain outlet for discharging the water in the slurry to the outside at the center, and taking out dehydrated gas hydrate that has been dehydrated and raised at the top. And a bed moving means for moving a bed formed of gas hydrate, which is a solid content in the slurry, upward in the dehydration tower.

  The bed moving means uses a slurry pump to feed the slurry into the dehydration tower from the slurry introduction part at the lower part of the dehydration tower at a constant feed rate, and raises the slurry. To form a continuous flow that flows out of the drain. Then, the bed is moved upward in the dehydration tower by the rising pressure generated by the continuous flow of the slurry inflow and drainage, and is moved to the dehydration gas hydrate take-out section located at the upper part of the dehydration tower. The water is gravity dehydrated by the difference in height between the drainage port and the drainage port so that it can reach the takeout portion as a dehydrated gas hydrate.

  If the concentration of the slurry fed into the dehydration tower is always constant, the amount of water in the slurry is always constant. Therefore, if a slurry with a constant concentration is sent into the dehydration tower using a slurry pump with a constant pressure, the flow rate of water that rises in the dehydration tower and is dehydrated and flows out from the drain outlet becomes constant per unit time, resulting in an increase caused by this. The pressure also becomes constant, and the rising speed of the bed moving upward in the dehydration tower becomes constant by this rising pressure, and the flow rate of the bed reaching the take-out portion above the dehydration tower is also constant per unit time. Then, a certain amount is taken out from the bet pushed up to the take-out portion and sent to the next process. Thereby, a dehydrated gas hydrate having a substantially constant concentration is always sent to the next process.

  The principle of gravity dehydration is that water is dropped and separated from the bed using gravity and capillary phenomenon due to the height difference between the take-out part at the upper part of the dehydration tower and the drain outlet at the middle part of the dehydration tower. If the height difference is increased more than necessary, the entire dehydrating apparatus becomes unnecessarily large, so that the size is set to a minimum size in view of safety within a range in which gravity dehydration can be reliably performed. Specifically, since the rising pressure and the rising speed of the bed are determined in accordance with the concentration of the slurry fed into the dehydrating tower, gravity dehydration is firmly performed according to the rising speed and there is no waste. Set to size.

JP 2005-263675 A

  However, it is not practically easy to always make the concentration of the slurry fed into the dehydration tower constant. Therefore, the slurry concentration may fluctuate, which causes the following problems. For example, when the slurry concentration is changed to a thin state, the proportion of water in the slurry increases by that amount, and as a result, the flow rate of water flowing out from the drain port increases. Thereby, the said raising pressure becomes large and the raising speed of a bet becomes high. As a result, there arises a problem that the bed reaches the take-out portion at the upper part of the dewatering tower in a state where the water content is high without being sufficiently dewatered by gravity.

  Further, when the slurry concentration is changed to a high state, the rising pressure is reduced, and the rising speed of the bet is lowered, thereby causing a problem that the throughput is lowered or the bet cannot be raised.

  An object of the present invention is to provide a gravity dehydration apparatus that can raise a bed at a constant speed without being affected even if the concentration of slurry fed into the dehydration tower fluctuates, thereby reliably performing gravity dehydration. An object of the present invention is to provide a gravity dehydration method and a gas hydrate production apparatus.

  In order to achieve the above object, according to a first aspect of the present invention, a slurry introduction part is provided in the lower part, a drain outlet for discharging water in the slurry to the outside is provided in the middle part, and a dehydrated product is taken out in the upper part. A gravity dehydration apparatus comprising: a vertically long dehydration tower provided with a section; and a bed moving means for moving a bed formed of solid content in the slurry upward in the dehydration tower, wherein the bed moving means Is provided in the dewatering tower, and includes a piston capable of moving from a lower part to an upper part in the dewatering tower and transmitting water, and a drive mechanism for moving the piston at a set speed. After the position of the drain outlet is exceeded, the bed is moved upward at the set speed by the piston.

  According to the gravity dehydration apparatus according to the first aspect of the present invention, after the bed exceeds the position of the drain outlet of the dewatering tower, the bed is set at a constant speed set by the piston provided in the dewatering tower. Since it is configured to move upward, even if the slurry concentration fed into the dewatering tower fluctuates, the bed can be raised at a constant speed without being affected by this, and gravity dewatering is reliably performed. be able to.

Further, according to a second aspect of the present invention, in the gravity dewatering device according to the first aspect, the drive mechanism constituting the bet moving means includes a rack and pinion structure and a power source. It is a feature.
According to the gravity dehydrating apparatus according to the second aspect of the present invention, the rack and pinion structure is used, so that the structure can be simplified and the ascending speed of the piston can be made constant.

  In the third aspect of the present invention, the slurry is fed into the vertically long dehydration tower from the lower part thereof, and the water in the slurry is discharged out of the tower from a drain outlet provided in the middle of the dehydration tower. A gravity dehydration method in which water is dropped and separated by gravity from the bed moved above the drain port by moving the bed formed in minutes above a predetermined height above the position of the drain port, After the bed has exceeded the position of the drain in the dewatering tower, the piston is moved at a set speed from the bottom upward in the dewatering tower, and the water is permeated by the movement of the piston. Is moved upward.

  According to the gravity dehydration method according to the third aspect of the present invention, as in the first aspect, even if the slurry concentration fed into the dehydration tower fluctuates, the bed is not affected by the fluctuation at a constant speed. Thus, gravity dehydration can be reliably performed.

  Moreover, the 4th aspect of this invention dehydrates the slurry of the produced | generated primary gas hydrate, the 1st production | generation part which produces | generates primary gas hydrate by making raw material gas and water react under low temperature and high pressure. A gas hydrate production apparatus comprising: a dehydrator; and a second generation unit that reacts the dehydrated primary gas hydrate with a raw material gas again to generate a high concentration secondary gas hydrate, The dehydrating apparatus is characterized by comprising the gravity dehydrating apparatus described in the first aspect or the second aspect.

  According to the gas hydrate manufacturing apparatus according to the present invention, even if the slurry concentration of the primary gas hydrate generated in the first generation unit varies, the subsequent dehydrator is not affected by the concentration variation. Through the reliable execution of gravity dehydration, it can be further sent to the second generation unit, so that a high concentration secondary gas hydrate can be stably generated.

  According to the present invention, after the bed exceeds the position of the drain outlet of the dewatering tower, the bed is moved upward at a set constant speed by a piston provided in the dewatering tower. Therefore, even if the concentration of the slurry fed into the dehydration tower fluctuates, the bed can be raised at a constant speed without being affected by this, and gravity dehydration can be reliably performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a gas hydrate manufacturing apparatus according to an embodiment of the present invention provided with a gravity dehydration apparatus according to an embodiment of the present invention. The gas hydrate manufacturing apparatus according to the present embodiment includes a first generator 1 that is a first generation unit that generates a primary gas hydrate 6 by reacting a raw material gas and water under low temperature and high pressure, The gravity dehydration device 2 for dehydrating the generated primary gas hydrate 6, the pulverizer 3 for pulverizing the dehydrated primary gas hydrate 7 to a uniform size, the pulverized primary gas hydrate 8 and the raw material gas react again. And a second generator 4 that is a second generation unit that generates a high-concentration secondary gas hydrate 9. The crusher 3 is provided in a cylindrical connecting pipe 5 in the present embodiment, which is a connecting portion between the gravity dehydrator 2 and the second generator 4.

  First, the first generator 1 and the first generation process will be described. The inside of the first generator 1 is adjusted to a predetermined temperature and pressure by a known method, and raw material gas and raw water are supplied to the first generator 1, where the production reaction of the primary gas hydrate 6 proceeds. In this embodiment, the temperature is 1 ° C. to 5 ° C., the pressure is 4 MPa to 8 MPa, preferably the temperature is 2 ° C. to 4 ° C., and the pressure is 5 MPa to 6 MPa.

  Since the specific gravity of the primary gas hydrate 6 is smaller than that of water, the primary gas hydrate 6 floats in water and is slurried. The generated primary gas hydrate 6 is extracted out of the first generator 1 in the slurry state and is subjected to a subsequent dehydration step by the gravity dehydrator 20. The slurry-like primary gas hydrate 6 contains a large amount of moisture, and the gas hydrate content is about 20 wt%.

Next, the gravity dehydrator 20 and the dehydration process will be described.
The primary gas hydrate 6 in the slurry state extracted from the first generator 1 is introduced into the dehydration tower 2 of the gravity dehydrator 20. This dehydration tower 2 is provided with a slurry introduction part 21 at the lower part, a drain port 22 for discharging water in the slurry to the outside is provided at the middle part, and a dehydration take-out part 23 is provided at the upper part. It has a vertically long shape. Slurry of the primary gas hydrate 6 is fed from the first generator 1 through the line 25 to the slurry introduction unit 21 using a slurry pump 24 at a constant feed rate. The water flowing out from the drain port 22 is returned to the first generator 1 through the line 26.

  In the present invention, a bed moving means 31 for moving the bed 30 formed by the gas hydrate which is solid content in the slurry in the dehydration tower 2 is provided. In the present embodiment, the bed moving means 31 is provided in the dehydration tower 2, and can move from the lower part to the upper part in the dehydration tower 2 and can pass water, and the piston 32. And a drive mechanism 33 that moves the bet 30 at a set speed, and after the bet 30 exceeds the position of the drain port 22, the piston 32 moves the bet 30 upward at a set constant speed. Has been. Here, the drive mechanism 33 includes a rack and pinion structure 34 and a power source (not shown).

The bed 30 of the primary gas hydrate 7 (hereinafter referred to as dehydrated primary gas hydrate) dehydrated by raising the dehydration tower 2 is pushed up to the take-out portion 23 at the top of the dehydration tower 2. The gas hydrate content of the dehydrated primary gas hydrate 7 is about 50 wt%.
The dehydrated primary gas hydrate 7 is further brought into contact with the gas in the second generator 4 at the subsequent stage to react with the gas, thereby increasing the gas hydrate content and increasing the gas storage amount and the high concentration secondary gas hydrate. 9 can be obtained.

  Next, the crusher and the crushing process will be described. The crusher 3 used in the crushing step is provided in the connecting pipe 5 between the dehydration tower 2 and the second generator 4, and is provided in the vicinity of the inlet 11 to the second generator 4. And a scraping portion 15 having a scraping action plate 14 at the tip of the shaft 13. The mesh portion 12 is provided immediately before the introduction port 11 to the second generator 4. The mesh of the mesh portion 12 is preferably 2 to 5 mm.

  The scraping action plate 14 passes through the take-out portion 23 of the dehydration tower 2 and is configured to be capable of reciprocating in the axial direction between the mesh portion 12. The shaft 13 has a structure that can be operated from the outside of the connecting pipe 5 manually or by a known power unit (not shown).

The crushing process will be described.
First, the dehydrated primary gas hydrate 7 pushed up to the take-out part 23 of the dehydration tower 2 is collected by sliding the collecting action plate 14 of the collecting part 15 along the bottom of the connecting pipe 5, Push to the mesh part 12 side. The dehydrated primary gas hydrate 7 is crushed to a uniform particle size by passing through the mesh portion 12. By repeating this crushing operation, the pulverized primary gas hydrate 8 having a uniform particle size is supplied to the second generator 4.

Next, the second generator 4 and the second generation process will be described.
The pulverized primary gas hydrate 8 crushed by the pulverization step is supplied to the second generator 4 from the inlet 11 on the downstream side of the mesh portion 12. In the second generator 4, the raw gas is blown and fluidized into the pulverized primary gas hydrate 8 having a gas hydrate content of about 50 wt%, and the residual water and raw material of the pulverized primary gas hydrate 8 are supplied. A second generation step is performed in which the gas is re-reacted to generate a high concentration secondary gas hydrate 9.
By the second generation step, a high concentration secondary gas hydrate 9 having a gas hydrate content of about 90 wt% can be obtained. The generated secondary gas hydrate 9 is sent to the next process by the screw conveyor 17.

Next, the operation of the gravity dehydration apparatus according to this embodiment will be described.
Slurry of the primary gas hydrate 6 is fed into the dehydration tower 2 from the slurry introduction part 21 below the slurry pump 24, and the bed 30 is formed while rising in the dehydration tower 2. When the water level of the slurry rises to the height of the drain port 22, the water flows out of the dehydration tower 2 from the drain port 22. On the other hand, the bed 30 does not flow out of the drain port 22 but remains in the dehydration tower 2. After that, the slurry is continuously fed by the slurry pump 24 for a short time, and the bed 30 is grown at the lower end by the rising pressure generated by the continuous flow of the slurry inflow and drainage. Make it start.

The slurry pump 24 is configured to stop at that timing. As a result, the rise of the bed 30 is stopped, and the bed 30 is not affected by fluctuations in the slurry concentration. Then, the drive mechanism 33 is turned on and the bed 30 is moved upward at a set constant speed by the piston 32 provided in the dewatering tower 2. This constant speed is set to a speed value at which gravity dehydration is reliably performed. Therefore, even if the slurry concentration fed into the dehydration tower 2 fluctuates, the bed 30 can be pushed up to the take-out portion 23 at the upper part of the dehydration tower 2 without being affected by this, and gravity dehydration is ensured. Can be done.
The

  Further, according to the gas hydrate manufacturing apparatus according to the present embodiment, even if the slurry concentration of the primary gas hydrate 6 generated in the first generator 1 fluctuates, Since it is not affected by the concentration fluctuation, it can be sent to the second generator 4 through the reliable execution of gravity dehydration, and the secondary gas hydrate 9 having a high concentration can be stably generated.

  The present invention feeds a slurry such as a gas hydrate slurry from the lower part to a vertically long dehydration tower, discharges water in the slurry from a drain outlet provided in the middle of the dehydration tower, and removes the solid content in the slurry. Gravity dewatering device configured to move and separate water by gravity from the bed moved above the drainage port by moving the bed formed at a predetermined height above the drainage port. It can be used for a gravity dehydration method and a gas hydrate production apparatus.

It is a schematic block diagram which shows the manufacturing apparatus of the gas hydrate which concerns on one embodiment of this invention provided with the gravity dehydration apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st generator, 2 Dehydration tower, 3 Crusher, 4 Second generator, 5 Connection pipe, 6 Primary gas hydrate, 7 Dehydrated primary gas hydrate, 8 Crush primary gas hydrate, 9 Secondary gas hydrate Rate, 11 inlet, 12 mesh part, 13 shaft part, 14 scraping action plate, 15 scraping part, 18 screw conveyor, 20 gravity dehydrator, 21 slurry introducing part, 22 drainage port, 23 takeout part, 24 slurry pump 25, 26 lines, 30 beds, 31 bed moving means, 32 pistons, 33 drive mechanism, 34 rack and pinion structure

Claims (4)

A slurry introduction part is provided in the lower part, a drainage port for discharging water in the slurry to the outside is provided in the middle part, and a vertically long dehydration tower provided with a dehydration takeout part in the upper part,
A bed moving means for moving the bed formed of the solid content in the slurry upward in the dewatering tower, and a gravity dewatering device comprising:
The bed moving means is provided in the dewatering tower, and includes a piston that can move from a lower part to an upper part in the dewatering tower and that can pass water, and a drive mechanism that moves the piston at a set speed. The gravity dewatering apparatus is configured to move the bet upward at the set speed by the piston after the bed exceeds the position of the drainage port.   2. The gravity dewatering apparatus according to claim 1, wherein the drive mechanism that constitutes the bed moving means includes a rack and pinion structure and a power source. The slurry is fed into the vertically long dewatering tower from the lower part, the water in the slurry is discharged out of the tower through a drain outlet provided in the middle of the dewatering tower, and the bed formed by the solid content in the slurry is A gravity dehydration method in which water is dropped and separated by gravity from the bed moved above the drainage port by moving it above a predetermined height above the position;
After the bed has exceeded the position of the drain in the dewatering tower, the piston is moved at a set speed from the bottom upward in the dewatering tower, and the water is permeated by the movement of the piston. Gravity dehydration method characterized by moving the water upward. A first generation unit that generates a primary gas hydrate by reacting a raw material gas and water under a low temperature and a high pressure, a dehydrator that dehydrates a slurry of the generated primary gas hydrate, and a dehydrated primary gas hydrate A gas hydrate manufacturing apparatus comprising: a second generation unit that reacts the raw material gas again with a source gas to generate a high concentration secondary gas hydrate,
The dehydrating apparatus comprises the gravity dehydrating apparatus according to claim 1 or 2, and a gas hydrate manufacturing apparatus.

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