JP2006194549A - Cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce energy consumption of a cooling system using clathrate as a refrigerant. <P>SOLUTION: In the cooling system 10, hydrate H is produced in a hydrate producing reactor 11 and transferred to a hydrate decomposition system 15 through a hydrate line 31. Environment is cooled by decomposition heat when decomposing the hydrate H into a liquid component L and a gas component G in the hydrate decomposition system 15. The hydrate line 31 is provided with a turbine 14. The turbine 14 is rotated by pressure energy of the hydrate transferred through the hydrate line 31, and a power conversion mechanism 18 converts rotational force of the turbine 14 into power of a pump 16 for boosting the liquid component L. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling system in which a clathrate generated by a clathrate generator is decomposed by a clathrate decomposer and the surroundings are cooled by absorbing heat.

  Conventionally, between a clathrate generator that generates a clathrate such as a hydrate and a clathrate decomposer that decomposes the clathrate generated by the clathrate generator into a gas component and a liquid component, A cooling system that circulates gas components and liquid components and cools the surroundings by an endothermic action when the clathrate is decomposed has been devised (see, for example, Patent Documents 1 and 2).

  In Patent Documents 1 and 2, a gas component and a liquid component decomposed by a clathrate decomposition apparatus are separated into gas and liquid, and the liquid component is pressurized by a pump when transferred to a clathrate generation apparatus by a liquid transfer line. Is compressed by a compressor when it is transferred to the clathrate generator in the gas transfer line. That is, instead of passing the entire amount of clathrate as a refrigerant through the compressor, the gas component and liquid component of the clathrate are separated and only the gas component passes through the compressor, thereby reducing the required power of the compressor. ing.

However, since the power of the pump that boosts the liquid component is required although it is much smaller than the compressor, the energy consumption of the entire system can not be reduced by the amount of reduction in the required power of the compressor, Further reduction is desired.
Japanese Patent Application No. 2002-40964 Japanese Patent Laid-Open No. 5-180522

  The present invention has been made in consideration of the above facts, and an object thereof is to reduce energy consumed in a cooling system that uses a clathrate as a refrigerant.

  The cooling system according to claim 1, wherein a clathrate generation device that supplies a clathrate generation liquid component and a clathrate generation gas component to generate a clathrate, and a class generated by the clathrate generation device A clathrate decomposition apparatus that decomposes the rate into a liquid component and a gas component and absorbs heat; a clathrate line that transfers the clathrate from the clathrate generation apparatus to the clathrate decomposition apparatus; and the clathrate from the clathrate decomposition apparatus A liquid line for transferring a liquid component to the generation device, a gas line for transferring a gas component from the clathrate decomposition device to the clathrate generation device, and a pump provided in the liquid line for boosting the liquid component to be transferred And a compressor provided in the gas line for compressing a gas component to be transferred. A system, comprising: a turbine that is provided in the clathrate line and that rotates using a transferred clathrate as a power source; and power conversion means that converts the rotational force of the turbine into power of the pump. And

  In the cooling system according to the first aspect, the clathrate generation liquid component and the clathrate generation gas component are supplied to the clathrate generation device to generate the clathrate. The clathrate generated by the clathrate generator is transferred from the clathrate generator to the clathrate decomposer via the clathrate line, and decomposed into a liquid component and a gas component by the clathrate decomposer. At this time, the cooling effect is exhibited by absorbing heat from the surroundings.

  Then, the liquid component is transferred from the clathrate decomposer to the clathrate generator through the liquid line, and the pressure is increased by the pump during that time. Further, the gas component is transferred from the clathrate decomposition apparatus to the clathrate generation apparatus by the gas line, and is compressed by the compressor during that time. As a result, the liquid component and the gas component supplied to the clathrate generating device become high pressure, and the clathrate is generated.

  Here, a turbine is provided in the clathrate line, and the turbine is rotated by the clathrate transferred in the clathrate line. And the rotational force of a turbine is converted into the motive power of a pump by a power conversion means. That is, the pressure energy of the transferred clathrate is recovered, and the recovered energy is used as driving energy for the pump. Thereby, the energy consumption of the whole system can be reduced.

  The cooling system according to claim 2 is the cooling system according to claim 1, further comprising an additive line that mixes the additive separated from the clathrate by the clathrate generator into the liquid line. Features.

  The cooling system according to claim 2, wherein the additive is added to the liquid line by the additive line, separated from the clathrate by the clathrate generator, and added to the liquid line by the additive line. The agent is circulated. As a result, the generation pressure of the clathrate can be lowered, so that the required power of the compressor and the pump can be lowered. Therefore, the energy consumption of the entire system can be reduced.

  The cooling system according to claim 3 is the cooling system according to claim 2, wherein the liquid component is water, the gas component is methane, the additive is tetrahydrofuran, and the water transferred in the liquid line. The concentration of the tetrahydrofuran contained is 10% by volume or more.

  In the cooling system according to the third aspect, the pressurized water and the compressed methane are supplied to the clathrate generator to generate a clathrate, and the clathrate is decomposed into water and methane by the clathrate decomposer.

  Here, tetrahydrofuran is added as an additive to the liquid line by the additive line, and the concentration of tetrahydrofuran contained in the liquid transferred through the liquid line is 10% by volume or more. That is, when the flow rate of water to be transferred is 90, the flow rate of mixed tetrahydrofuran is 10 or more.

  The cooling system according to claim 4 is the cooling system according to any one of claims 1 to 3, wherein a clathrate transported in the clathrate line with a liquid component transported in the liquid line is provided. It has a cooling device for cooling.

  In the cooling system according to the fourth aspect, the cooling device cools the clathrate transferred in the clathrate line by the liquid component transferred in the liquid line. As a result, the temperature of the clathrate transferred to the clathrate generator is further lowered, so that the amount of heat absorbed when the clathrate is decomposed into a liquid component and a gas component is increased, and the cooling effect is improved.

  The cooling system according to claim 5 is the cooling system according to any one of claims 1 to 4, wherein the clathrate is a hydrate, and the clathrate generator is a hydrate generator. The clathrate decomposing apparatus is a hydrate decomposing apparatus.

  In the cooling system according to the fifth aspect, the hydrate is generated by the hydrate generator, decomposed into the gas component and the liquid component by the hydrate decomposer, and absorbs heat. As a result, a cooling effect is exhibited.

  Since the present invention is configured as described above, it is possible to reduce the energy consumed by the cooling system that uses the clathrate as a refrigerant.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, in the refrigeration system 10, a gas hydrate H (gas sachet), which is a kind of clathrate, is composed of a gas component G of a lower hydrocarbon such as methane and a liquid component L such as water (or oil) as a refrigerant. Contact compound).

  As the gas component G forming the gas hydrate H, for example, a single component of lower hydrocarbons such as methane, ethane, propane, butane or a mixed gas of these plural components can be used. In the embodiment, methane is used. Further, as the liquid component L, water, oil or the like can be used, but water is used in the present embodiment.

  Furthermore, additive A can also be used to adjust the production and decomposition conditions of gas hydrate H in the refrigeration system 10. The additive A added to the liquid component L of the gas hydrate H includes so-called hydration inclusion promoter, hydrate stabilizer, and hydrate decomposer. Use accelerated hydration inclusion promoter. By using this hydration inclusion promoter, the pressure during hydrate formation can be reduced and the temperature can be increased.

  As this hydration inclusion promoter A, for example, tetrahydrofuran, 1,3-dioxolane, furan, cyclobutanone, cyclopentanone, special salts, lecithin, PVA, PVCCap, acetone, methanol, sodium chloride, glycol, etc. should be used. In this embodiment, tetrahydrofuran is used.

  The refrigeration system 10 includes a hydrate generation reactor 11, a cooler (cooler) 12, a cold heat recovery device 13, a turbine 14, a hydrate decomposition system (chiller) 15, a pump 16, a compressor (compressor) 17, and power conversion. Means 18 are provided.

  In the refrigeration system 10, devices are connected by a hydrate line 31, a gas line 32, a liquid line 33, a cooling line 34, and an additive line 35.

  The hydrate line 31 sequentially connects the hydrate generation reactor 11, the cold heat recovery device 13, the turbine 14, and the hydrate decomposition system 15, and the gas line 32 includes the hydrate decomposition system 15, the compressor 17, and the hydrate generation reactor 11. Are connected sequentially.

  The liquid line 33 sequentially connects the hydrate decomposition system 15, the pump 16, the cold heat recovery device 13, and the hydrate generation reactor 11, and the cooling line 34 includes the hydrate generation reactor 11, the pump 36, the cooler 12, and the hydrate. The production reactor 11 is sequentially connected.

  Further, the additive line 35 sequentially connects the hydrate production reactor 11, the additive receiving container 22, and the liquid line 33.

  In this refrigeration system 10, the slurry-like gas hydrate H produced in the hydrate production reactor 11 is pressurized and sent from the pump 16 to the hydrate production reactor 11 by the cold heat recovery device 13 through the hydrate line 31. After being cooled by the liquid component L, the gas enters the turbine 14 and is depressurized. The hydrate decomposition system 15 downstream thereof absorbs heat from the surroundings and decomposes it into a gas component G and a liquid component L.

  The hydrate decomposition system 15 includes a hydrate decomposition reactor 15a, a liquid / gas separator 15b, and a liquid receiver 15c, and utilizes the large decomposition heat of the gas hydrate H when the gas hydrate H is decomposed. The surroundings can be efficiently cooled. Since the gas hydrate H is cooled by the cold heat recovery device 13 and the temperature of the gas hydrate H is further lowered, the amount of heat absorbed when the gas hydrate H is decomposed is increased, and the cooling effect is improved.

  An example of calculation of the decomposition heat of the gas hydrate H is as follows. In the case of a methane gas hydrate having a weight ratio of methane: water of 1: 6.75, MW (molecular weight) = 125, and the heat of molar decomposition is 12.95 kcal / In mol, the heat of decomposition per kg of hydrate is 103.6 kcal / kg.

  The hydrate decomposition reactor 15a, the liquid / gas separator 15b, and the liquid receiver 15c may be integrated, or when the amount of heat absorption is large, the heat absorber may be provided in the external circulation line of the integrated body. However, it is also possible to form each container separated as described above.

  The liquid component L and the gas component G decomposed in the hydrate decomposition reactor 15a are separated by the liquid / gas separator 15b, and the liquid component L accumulated in the liquid receiver 15c is separated by the pump 16 through the liquid line 33. The gas hydrate H that has been pressurized and cooled by the cold heat recovery device 13 is cooled before being sent to the hydrate production reactor 11. The separated gas component G is pressurized and compressed by the compressor 17 through the gas line 32 and sent to the hydrate generation reactor 11.

  In the hydrate generation reactor 11, the liquid mixture or liquid component Lh containing the solid is maintained at a high pressure, and the external cooling medium and heat formed by seawater, cooling water, low-temperature water, brine, and the like in the cooler 12. The heat of the gas hydrate H side is dissipated to the external cooling medium, cooled, and returned to the hydrate generation reactor 11 to cool the gas hydrate H.

  Further, the additive A that promotes the generation of the gas hydrate H, which is separated when the gas hydrate H is generated in the hydrate generation reactor 11, is supplied to the upstream side of the pump 16 through the additive line 35, and the liquid component Mix to L.

  Note that the flow rate of tetrahydrofuran as the additive A supplied to the liquid line 33 by the additive line 35 is set to 10% or more with respect to the total flow rate of the liquid transferred by the liquid line 33, and the liquid line 33 transfers the liquid. The concentration of tetrahydrofuran in the liquid is 10% by volume or more.

  This is because, as shown in the graph of FIG. 2, when the concentration of tetrahydrofuran is 10% by volume or more, the effect of lowering the generation pressure of methane gas hydrate is recognized.

  The gas component G is taken into the liquid component L and the gas hydrate H is generated in the high pressure and low temperature state by the cooling of the cooler 12 and the pressure increase of the pump 16 and the compressor 17.

  By repeating this refrigeration cycle, the hydrate decomposition system 15 exhibits a refrigeration function.

  And in this hydrate production | generation reactor 11, when the pressure is high, the pressure resistance of the container becomes a problem, and when the pressure is low, the gas hydrate H is not produced, and when the temperature is high, the gas hydrate H is decomposed, When the temperature is 0 ° C. or lower, the liquid component L freezes and the generation efficiency of the gas hydrate H is lowered. Therefore, it is important to maintain an appropriate pressure and temperature.

  Therefore, the circulation rate of the gas hydrate H, liquid component L, and gas component G, and the heat exchange amount of the hydrate decomposition system 15, the cold heat recovery device 13, and the cooler 12 are controlled by a sensor and a pressure control device (not shown). Adjust and control the pressure and temperature in each device.

  Here, in this embodiment, tetrahydrofuran as the additive A is mixed in the water as the liquid component L at the above-described concentration, and the generation pressure of the methane gas hydrate is reduced as much as possible. The pressure of the component G can be greatly reduced. For this reason, the pressure | voltage resistance problem of the container of the hydrate production | generation reactor 11 is eliminated. Further, since the power of the pump 16 and the compressor 17 can be greatly reduced, energy consumption can be reduced.

  As a result, the pressure and temperature of the hydrate generation reactor 11 are set to 5.0 MPa, 25 ° C., the pressure and temperature of the hydrate decomposition system 15 are set to 0.69 MPa, and the temperature is 10 ° C., and the hydrate decomposition system 15 is cooled. However, it is possible to obtain a brine temperature of 15 ° C. supplied to the outside.

  By the way, the slurry-like hydrate H transferred by the hydrate line 31 rotates the turbine 14 with pressure energy. The rotating shaft of the turbine 14 and the rotating shaft of the drive source of the pump 16 are connected by a power conversion mechanism 18, and the rotational force of the turbine 14 is converted into the power of the pump 16. That is, the pressure energy of the transferred hydrate H is recovered, and the recovered energy is used as driving energy for the pump 16.

  Here, as shown in the table of FIG. 3, the energy consumed by the compressor 17 and the pump 16 to obtain the refrigerating capacity of 660000 kcal / Hr (220 USRT) 147 kw ((compressor: 102 kw) + (pump: 45 kw)), but in the refrigeration system 10 of this embodiment in which power is recovered by the turbine 14, 118 kw ((compressor: 102 kw) + (pump) : 45 kW)-(turbine: 29 kW)). That is, by recovering power by the turbine 14, the energy consumption of the entire refrigeration system 10 can be reduced by about 20%.

  In the present embodiment, the cooling system of the present invention has been described by taking the refrigeration system 10 as an example. However, it is not essential to freeze the object to be cooled, and the present invention can be applied even when the object is simply cooled. It is.

  In this embodiment, gas hydrate is used as the refrigerant. However, the present invention is not limited to this, and other clathrates can be used as the refrigerant.

  Further, in the present embodiment, the power conversion means of the present invention has been described taking the rotary power conversion mechanism 18 as an example, but as shown in FIG. 4, a reciprocating power conversion mechanism 50 is also applied to the present invention. Is possible.

It is a figure which shows schematic structure of the cooling system of this embodiment. It is a graph which shows the production | generation equilibrium data of methane gas hydrate. It is a table | surface which shows the comparison with the energy consumption of the cooling system of this embodiment, and the cooling system of a prior art. It is a figure which shows schematic structure of the modification of the cooling system of this invention.

Explanation of symbols

10 Cooling system 11 Hydrate generation reactor (clathrate generation device)
13 Cold energy recovery device (cooling device)
14 Turbine 15 Hydrate decomposition system (clathrate decomposition device)
16 Pump 17 Compressor 18 Power conversion mechanism (power conversion means)
31 Hydrate line 32 Gas line 33 Liquid line 35 Additive line H Hydrate (clathrate)
G Gas component L Liquid component A Additive

Claims (5)

A clathrate generation device that is supplied with a liquid component for clathrate generation and a gas component for clathrate generation to generate a clathrate;
A clathrate decomposition apparatus that decomposes the clathrate generated by the clathrate generation apparatus into a liquid component and a gas component and absorbs heat;
A clathrate line for transferring a clathrate from the clathrate generator to the clathrate decomposer;
A liquid line for transferring a liquid component from the clathrate decomposer to the clathrate generator;
A gas line for transferring a gas component from the clathrate decomposition apparatus to the clathrate generation apparatus;
A pump provided in the liquid line for boosting the liquid component to be transferred;
A compressor that is provided in the gas line and compresses a gas component to be transferred;
A cooling system comprising:
A turbine that is provided in the clathrate line and that rotates using the transferred clathrate as a power source;
Power conversion means for converting the rotational force of the turbine into the power of the pump;
A cooling system comprising:   The cooling system according to claim 1, further comprising an additive line for mixing the additive separated from the clathrate in the clathrate generator into the liquid line.   3. The liquid component is water, the gas component is methane, the additive is tetrahydrofuran, and the concentration of tetrahydrofuran contained in water transferred through the liquid line is 10% by volume or more. The cooling system described.   The cooling system according to any one of claims 1 to 3, further comprising a cooling device that cools the clathrate transferred in the clathrate line with a liquid component transferred in the liquid line.   5. The method according to claim 1, wherein the clathrate is a hydrate, the clathrate generator is a hydrate generator, and the clathrate decomposer is a hydrate decomposer. The cooling system described.

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