JP2006096867A - Hydrate-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a circulating water line from being clogged by hydrate. <P>SOLUTION: In a hydrate-forming apparatus 100, the density of the water which is circulated through a circulating water line 26 is detected by a micromotion flowmeter 29, and when the density of water which is circulated through the circulating water line 26 comes to a predetermined value or lower, the feed amount of water into a tank 6 of a water feed line 18 is increased. By doing so, the content of a hydrate in the tank 6 is decreased and, consequently, the amount of the hydrate flowing into the circulating water line 26 is inhibited to decrease the slurry concentration in the circulation water line 26. Accordingly, clogging of the circulating water line 26 by the hydrate can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrate generating apparatus that supplies hydrate forming gas and water into a tank and generates hydrate under a predetermined temperature and a predetermined pressure.

  Conventionally, a technology has been developed in which natural gas and water are introduced into a tank and stirred at a predetermined temperature and a predetermined pressure to generate a natural gas hydrate (hereinafter referred to as NGH) (for example, NGH) (for example, Patent Documents 1 to 4). In Patent Documents 1 to 4, in order to cool the inside of the tank to a predetermined temperature, the water in the tank is circulated through a circulating water line including a cooling device.

Here, not only water but also natural gas flows into the circulating water line. For this reason, if the temperature and pressure in the circulating water line exceed the NGH generation boundary, NGH will be generated in the circulating water line. In addition, hydrate generated in the tank also flows into the circulating water line. Along with this, when the NGH content rate (slurry concentration) of the water circulating in the circulating water line rises to a predetermined value or more, the fluidity of the water in the circulating water line deteriorates and the circulating water line is blocked with NGH. End up. When this happens, the NGH production line must be stopped once and the NGH must be removed from the circulating water line, resulting in a decrease in NGH productivity.
JP 2004-10686 A JP 2000-264852 A JP 2000-302701 A JP 2000-309785 A

  The present invention has been made in consideration of the above facts, and an object thereof is to prevent the circulating water line from being blocked by hydrate.

  The hydrate generating apparatus according to claim 1, wherein water and hydrate forming gas are introduced into the tank, and the hydrate generating apparatus generates hydrate under a predetermined temperature and a predetermined pressure. A circulating water line that cools and circulates and cools the water in the tank to a predetermined temperature, a concentration detector that is provided in the circulating water line and detects a slurry concentration of the circulating water, and is detected by the concentration detector And a control means for increasing the water supply amount of the water supply means for supplying water into the tank when the slurry concentration is increased to a predetermined value.

  In the hydrate generating apparatus according to the first aspect, a hydrate forming gas such as natural gas and water are introduced into the tank, and hydrate is generated at a predetermined temperature and a predetermined pressure. Here, the water in the tank is cooled to a predetermined temperature by being cooled and circulated in the circulating water line, but not only water but also hydrate forming gas flows into the circulating water line. For this reason, when the temperature and pressure of the circulating water line exceed the hydrate generation boundary, hydrate is generated in the circulating water line, and the slurry concentration of the circulating water increases. In addition, the hydrate generated in the tank also flows into the circulating water line, so that the concentration of the circulating water slurry increases. This slurry concentration is detected by the concentration detection means, and when it rises to a predetermined value, the control means increases the water supply amount of the water supply means for supplying water into the tank from the set amount. Thereby, the production rate of hydrate in the tank is suppressed, the content rate of hydrate in the tank is reduced, and thus the amount of hydrate flowing into the circulating water line is suppressed. Therefore, the slurry concentration of the water circulating through the circulating water line is indirectly lowered, and the circulating water line is prevented from being blocked by hydrate.

  The hydrate generation device according to claim 2 is the hydrate generation device according to claim 1, wherein the control means increases the amount of water supplied into the tank of the water supply means, Water is supplied from the water supply means to the circulating water line.

  In the hydrate generator according to claim 2, when the slurry concentration of the water circulating in the circulating water line detected by the concentration detecting means rises to a predetermined value, the control means feeds water from the water supplying means to the circulating water line. Increase the flow rate of water circulating through the circulating water line. As a result, the slurry concentration of the water circulating directly through the circulating water line is reduced, and blockage of the circulating water line due to hydrate is prevented.

  The hydrate generating device according to claim 3 is the hydrate generating device according to claim 1, wherein the control means increases the amount of water supplied into the tank of the water supplying means at a predetermined rate. The water supply means supplies water to the circulating water line at a predetermined rate.

  In the hydrate generating apparatus according to claim 3, when the slurry concentration of the circulating water in the circulating water line detected by the concentration detecting means rises to a predetermined value, the control means reduces the amount of water supplied into the tank of the water supplying means. While increasing at a predetermined rate, water is supplied from the water supply means to the circulating water line at a predetermined rate. As a result, the water level in the tank and the slurry concentration of water circulating in the circulating water line can be maintained in a well-balanced manner.

  The hydrate generating device according to claim 4 is the hydrate generating device according to any one of claims 1 to 3, wherein the concentration detecting means detects the density of the circulating water and thereby slurry. It is characterized by calculating the density.

  The density of water circulating in the circulating water line is measured by, for example, a micro motion flow meter. When the circulating water passes through the curved pipe, this flow meter measures the resistance value that the curved pipe receives from the circulating water and converts it to the density of the circulating water. The density and the slurry concentration have a negative correlation, and when the density of circulating water decreases, the concentration increases, and when the density increases, the concentration decreases.

  This is because hydrate has a lower specific gravity than water, and therefore the density of circulating water decreases as the hydrate content increases, and the density of circulating water increases as the hydrate content decreases. It is.

  Therefore, in the hydrate generator according to claim 4, the density of the water circulating in the circulating water line is detected to calculate the slurry concentration of the circulating water line, and based on the calculated slurry concentration. Any one control of thru | or 3 is performed.

  Since the present invention is configured as described above, it is possible to prevent the circulating water line from being blocked by hydrate.

1. Embodiment 1
Hereinafter, an example of the hydrate generator of the present invention will be described.

1-1 Configuration As illustrated in FIG. 1, a hydrate generation device 100 according to Embodiment 1 includes a first generation device 2 that generates water by bringing water and natural gas into contact with each other, and a first generation device 2. A second generation device 4 that is positioned below and further contacts natural gas with the hydrate generated by the first generation device 2 is provided.

  The first generator 2 has an open top surface, a tank 6 in which water and natural gas are brought into contact with each other at a predetermined temperature and a predetermined pressure, and the tank 6 is housed inside and externally connected to the second generator 4 A tank 8, a stirrer 10 that stirs water and natural gas in the tank 6, and a hydrate discharge scraper 12 that is provided coaxially with the stirrer 10 and leads the hydrate generated in the tank 6 to the external tank 8. .

  The external tank 8 has an upper surface that is open and includes a main body 8B that accommodates the tank 6 and a lid portion 8A that covers the upper surface opening of the main body 8B.

  The stirrer 10 includes a rotating shaft 10C that vertically penetrates the lid 8A, a stirring blade 10A provided at the lower end of the stirring blade 10C, and a motor 10B that rotates the rotating shaft 10C. On the other hand, the hydrate discharge scraper 12 is rotated independently of the stirrer 10 by the motor 12B via the rotational force transmission device 12A provided coaxially with the rotating shaft 10C of the stirrer 10.

  The lid 8A of the external tank 8 is further provided with a gas supply line 14 for supplying natural gas to the tank 6 and a pressure release line 16 for releasing the pressure when the inside of the external tank 8 exceeds a predetermined pressure.

  The main body 8A and the tank 6 of the external tank 8 are provided with a jacket 8C and a jacket 6A, respectively, and the inside of the external tank 8 and the tank 6 has a predetermined temperature by circulating a refrigerant of a predetermined temperature through the jacket 8C and the jacket 6A. Is held in.

  The tank 6 is provided with a water supply line 18 for supplying water from the outside, a circulating water line 20 for cooling and circulating the water in the tank 6, and a circulating gas line 22 for circulating the gas in the tank 6. .

  Further, in the vicinity of the bottom of the tank 6, a gas blowing pipe 24 having gas blowing holes formed at predetermined intervals is provided horizontally.

  One end of the circulating water line 20 is connected to a circulating water extraction line 26 provided at the bottom of the tank 6, and the other end is connected to a circulating water return line 28 that returns the circulating water to the inside of the tank. The outlet of the circulating water return line 28 opens in the tank 6 below the water level.

  The circulating water line 20 includes a pump P that circulates the circulating water extracted from the circulating water extraction line 26 in the direction of arrow a, and a micro motion flow meter that is located downstream of the pump P with respect to the circulating direction a of the circulating water. 29, a heat exchanger 30 positioned downstream of the micro motion flow meter 29, and a temperature sensor 32 positioned downstream of the heat exchanger 30, that is, in the vicinity of the circulating water return line 28 are interposed. The heat exchanger 30 is controlled by the CPU 34. Moreover, when the circulating water passes through the curved pipe, the micro motion flow meter 29 measures the resistance value that the curved pipe receives from the circulating water, and converts it into the density of the circulating water.

  Here, not only water but also hydrate generated in the tank 6 flows into the circulating water line 26. When the gas in the tank 6 flows into the circulating water line 26 and the temperature and pressure in the circulating water line 26 exceed the hydrate generation boundary, hydrate is generated in the circulating water line 26. When the hydrate content (slurry concentration) of the circulating water in the circulating water line 26 increases, the fluidity of the water in the circulating water line 26 deteriorates, and when the slurry concentration exceeds a predetermined value, the circulating water line 26 Occluded by hydrate.

  By the way, the specific gravity of hydrate is smaller than that of water, and when the hydrate content in the circulating water increases, the density of the circulating water decreases. When the hydrate content in the circulating water decreases, the density of the circulating water increases. . Therefore, as shown in FIG. 3, the density and the slurry concentration have a negative correlation. When the circulating water density decreases, the slurry concentration increases, and when the circulating water density increases, the slurry concentration decreases.

  As described above, the circulating water line 26 is closed when the slurry concentration exceeds a predetermined value. In other words, the circulating water line 26 is closed when the concentration of the circulating water falls below a predetermined value.

  Therefore, in the hydrate generator 100, when the concentration of the circulating water detected by the micro motion flow meter 29 decreases to a predetermined value or less, the CPU 34 increases the amount of water supplied to the tank 6 by the water supply line 18 from the set amount. The density of water in the tank 6 is increased, and the content of hydrate and hydrate-forming gas in the tank 6 is decreased. As a result, the amount of hydrate and hydrate forming gas flowing into the circulating water line 26 can be suppressed, and the slurry concentration of the circulating water in the circulating water line 26 can be lowered indirectly. Therefore, blockage of the circulating water line 26 due to hydrate can be prevented.

  On the other hand, one end of the circulating gas line 22 is connected to a circulating gas extraction line 38 provided in the lid portion 8 </ b> A of the external tank 8, and the other end is connected to the gas blowing pipe 24.

  The circulating gas line 22 includes a compressor 40 that compresses the circulating gas extracted from the circulating gas extraction line 38 and pumps it in the direction of the arrow b, and heats or cools the circulating gas compressed by the compressor 40 to a predetermined temperature. A heat exchanger 42 is interposed.

1-2 Actions and Effects In the first generator 2, a coolant having a temperature is circulated through the jacket 6 </ b> A and the jacket 8 </ b> C to keep the inside of the tank 6 and the external tank 8 at a predetermined temperature, and the water supply line 18 to the tank 6. A predetermined amount of water is supplied to the circulating water line 20, and the circulating water return temperature T ₁ is maintained at a predetermined temperature by the heat exchanger 30 while circulating the water in the circulating water line 20.

  When natural gas is supplied to the external tank 8 through the gas supply line 14 while rotating the stirrer 10, the supplied natural gas is transported with water in the tank 6 to generate hydrate. The generated hydrate is discharged into the external tank 8 by the hydrate discharge scraper 12 and led out to the second generator 4 from the external tank 8. The hydrate led out from the external tank 8 to the second generator 4 has a conversion of about 40% and contains about 60% by weight of water.

  In the second generator 4, the hydrate introduced from the first generator 2 is agitated by the rotating paddle 44 and further brought into contact with natural gas, whereby the hydrate conversion rate is reduced to about 90%. Increase.

  Further, the concentration of water circulating in the circulating water line 26 is detected by the micro motion flow meter 29, the slurry concentration in the circulating water line 26 is calculated from the detected water concentration, and the calculated slurry concentration is a predetermined value. By controlling the amount of water supplied to the tank 6 so as not to become higher, the circulating water line 26 can be prevented from being blocked by hydrate.

2. Embodiment 2
Hereinafter, an example of the hydrate generator of the present invention will be described.

  As shown in FIG. 3, in the hydrate generator 110 according to the second embodiment, one end of a tributary (hereinafter referred to as a water supply line tributary) 18 </ b> A of the water supply line 18 is connected to the water supply line 18 via a three-way valve 19. Yes. The other end of this water supply line branch 18 </ b> A is connected to the circulating water line 20 via an on-off valve 21.

  When the concentration of circulating water in the circulating water line 26 detected by the micro motion flow meter 29 falls below a predetermined value, the CPU 35 switches the three-way valve 19 to flow water from the water supply line 18 to the water supply line branch 18A, and opens and closes it. The valve 21 is opened and water is supplied directly to the circulating water line 26.

  As a result, the slurry concentration of the water directly circulating in the circulating water line 26 is reduced, and blockage of the circulating water line 26 due to hydrate is prevented.

3. Embodiment 3
Hereinafter, an example of the hydrate generator of the present invention will be described.

  As shown in FIG. 3, in the hydrate generator 110 according to the third embodiment, the three-way valve 19 not only switches the water flow to the water supply line 18 and the water supply line branch 18 </ b> A on and off, but continuously at an arbitrary rate. Can be sorted. When the concentration of the circulating water in the circulating water line 26 detected by the micro motion flow meter 29 decreases to a predetermined value or less, the CPU 37 adjusts the three-way valve 19 to supply the water flowing through the water supply line 18 and the water supply line branch 18A in three directions. The valve 19 is branched at a predetermined rate, and the on-off valve 21 is opened to supply water to both the tank 6 and the circulating water line 26.

  At this time, the CPU 37 controls the opening degree of the three-way valve 19 to increase the amount of water supplied from the water supply line 18 into the tank 6 at a predetermined rate, and at a predetermined rate from the water supply line branch 18A to the circulating water line 26. To supply water. Thereby, the water level in the tank 6 and the slurry concentration of the water circulating in the circulating water line 26 can be maintained in a well-balanced manner.

  In the first to third embodiments, the present invention has been described by taking as an example a configuration in which the hydrate is discharged from the tank 6 at the same time as the hydrate is generated. However, the present invention is not limited to this, and even a so-called batch-type hydrate generating device that continues to generate hydrate until a predetermined amount of hydrate has accumulated in the tank without discharging the hydrate from the tank 6 can be stored in the tank. When water is circulated in the circulating water line, the problem of clogging due to hydrate can occur as well. Therefore, the present invention can also be applied to a batch type hydrate generating apparatus.

1 is a schematic diagram illustrating a configuration of a hydrate generation device according to Embodiment 1. FIG. It is a graph which shows the correlation with the density of circulating water, and a slurry density | concentration. It is the schematic which shows the structure of the hydrate production | generation apparatus which concerns on Embodiment 2, 3. FIG.

Explanation of symbols

6 Tank 18 Water supply line (Water supply means)
20 Circulating water line 29 Micro motion flow meter (concentration detection means)
34 CPU (control means, concentration detection means)
35 CPU (control means, concentration detection means)
37 CPU (control means, concentration detection means)
100 Hydrate Generator 110 Hydrate Generator

Claims (4)

In a hydrate generating device for introducing water and hydrate forming gas into a tank and generating hydrate under a predetermined temperature and a predetermined pressure,
A circulating water line for cooling and circulating the water in the tank, and cooling the water in the tank to a predetermined temperature;
A concentration detecting means provided in the circulating water line for detecting the concentration of the circulating water slurry;
Control means for increasing the water supply amount of the water supply means for supplying water into the tank from a set amount when the slurry concentration detected by the concentration detection means rises to a predetermined value;
A hydrate generation apparatus comprising:   2. The hydrate according to claim 1, wherein the control means feeds water from the water supply means to the circulating water line instead of increasing the amount of water supplied into the tank of the water supply means. Generator.   The control means increases the amount of water supplied into the tank of the water supply means at a predetermined rate and supplies water from the water supply means to the circulating water line at a predetermined rate. The hydrate generation device described in 1.   The hydrate generating apparatus according to any one of claims 1 to 3, wherein the concentration detecting means calculates a slurry concentration by detecting a density of circulating water.

Images