JP5353198B2 - Hydrate production method and apparatus using heat storage tank - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a hydrate generation method and apparatus using a heat storage tank that generates clathrate hydrate with a liquid guest substance and water as a host substance in the heat storage tank.

  Methane hydrate is known as a general hydrate, but the guest substance is methane gas, which may be used for methane storage. However, it can be used for storage of methane. As a medium, the pressure and temperature conditions for producing the hydrate do not match the heat storage application.

  As an example of using a slurry-like hydrate instead of cold water or ice as a cold storage material, in Patent Documents 1 and 2, an aqueous solution of tetra n-butylammonium salt (TBAB) is used, and this is cooled to 5 It has been proposed that a regenerator material is obtained by converting a liquid to a slurry hydrate at -8 ° C.

  However, TBAB is a white crystalline powder that is soluble in water, and is used as a TBAB aqueous solution having a concentration of 20% or more. However, as a hydrate, there is a problem that heat of decomposition is small.

  The present inventor uses a cyclic hydrocarbon as a guest material, and produces a hydrate with the guest material and water, more specifically, a liquid guest material composed of cyclopentane and water as a host material. A method of directly cooling the interface of the solution to form a hydrate (Japanese Patent Application No. 2007-129563), and emulsifying a liquid guest substance composed of cyclopentane and water with a surfactant to form a dispersion, which is cooled Thus, a method for producing a hydrate (Japanese Patent Application No. 2007-129553) was proposed.

  The hydrate is cooled by contacting water as a host and a liquid as a guest material, and the guest is encapsulated in an inclusion lattice constituted by water molecules to crystallize to form a hydrate. However, by appropriately selecting the hydrocarbon liquid of the guest material, a wide range of generation temperatures can be obtained from 0 ° C or higher to minus several tens of ° C. After decomposition, both the host and guest are liquid. There is no pressure loss, and it is possible to make it possible to provide a heat storage and cold heat source suitable for the purpose of use.

Japanese Patent Laid-Open No. 2004-3718 JP 2005-291516 A

  In general, hydrates have supercooling properties, and hydrates do not form unless supercooling is released or contacted with seed crystals in the same manner as water.

  When cyclopentane is used as a guest substance, as shown in FIG. 5, the supercooling of water is canceled to generate ice, and hydrates grow using this as seed crystals, or as shown in FIG. Hydrate grows by adding seed crystals of hydrate.

  However, in order to cancel the supercooling of water, a low temperature of about −6 ° C. is necessary, and the power of the cooling heat source that makes a temperature much lower than the temperature necessary for hydrate formation is wasted. Further, when seed crystals are added, it becomes virtually impossible when there are an infinite number of containers filled with the heat storage material in the heat storage tank, such as capsules.

  Therefore, the object of the present invention is to solve the above-mentioned problems and to adjust the main cold source temperature or to physically convert the seed crystal when producing a hydrate with a liquid guest substance and water as a host substance. It is an object to provide a hydrate generation method and apparatus using a heat storage tank that can stably generate hydrates with low power without being charged into the tank.

In order to achieve the above-mentioned object, the invention of claim 1 contains a liquid guest substance and water as a host substance in a heat accumulator, accommodates the heat accumulator in a heat accumulator, and supplies a refrigerant to the heat accumulator. When the refrigerant is filled and cooled by the main cooler to produce clathrate hydrate with the guest substance and water in the heat storage body, the heat storage body is placed between the upper header pipe and the lower header pipe. The superheater is provided in the upper header pipe of the heat storage body, and the heat storage body is about −2 ° C. with respect to the temperature of clathrate hydrate formation with the refrigerant. Supercooling to a low temperature, and in the supercooling section, the liquid guest substance and water are supercooled to a temperature lower than the temperature of the refrigerant to form a clathrate hydrate species, based on the species, Propagating hydrate formation from the upper header tube to the lower header tube to produce clathrate hydrate A hydrate formation method using the thermal storage tank to symptoms.

  The invention of claim 2 is a method for producing a hydrate using a heat storage tank according to claim 1, wherein a surfactant is mixed into a liquid guest substance and water to form a dispersion, and the dispersion is accommodated in the heat storage body. is there.

Invention of Claim 3 is the hydrate production | generation method using the thermal storage tank of Claim 1 or 2 which was made to circulate the guest substance and water in the upper header pipe | tube of the said thermal storage body to the said supercooling part. .

  Invention of Claim 4 is a hydrate production | generation method using the thermal storage tank in any one of Claims 1-3 in which a supercooling part consists of a cooling coil or a thermoelectric element with which a refrigerant | coolant flows.

According to the fifth aspect of the present invention, a liquid guest substance and water as a host substance are accommodated in a heat accumulator, the heat accumulator is accommodated in a heat accumulator, the refrigerant is filled in the heat accumulator, and the refrigerant is mainly used. In a hydrate generating apparatus using a heat storage tank that cools with a cooler and generates a clathrate hydrate with a guest substance and water in the heat storage body, the heat storage body is placed between the upper header pipe and the lower header pipe. It is composed of a multi-tube collecting pipe connected with a heat transfer pipe, and the refrigerant is supercooled in the heat storage tank at a temperature lower by about −2 ° C. than the generation temperature of the clathrate hydrate by the refrigerant. A main refrigerating machine, and a supercooling section that forms a seed of clathrate hydrate by supercooling to a temperature lower than the temperature of the refrigerant in an upper header pipe of the heat storage body It is a hydrate production | generation apparatus using a tank .

Hydration invention of claim 6, in which the upper header pipe, a guest material and the liquid water of the upper header pipe, with a heat storage tank according to claim 5, wherein connecting a circulation line for circulating the supercooling part It is a product generation device.

The invention according to claim 7 is the hydrate generating device using the heat storage tank according to claim 5 or 6 , wherein the supercooling section is formed of a cooling coil or a thermoelectric element through which a refrigerant flows.

  According to the present invention, the liquid guest material and the host material water are accommodated in the heat storage body, and the clathrate hydrate is obtained by supercooling the liquid guest material and water in the supercooling section provided in the heat storage body. By forming the seeds, the clathrate hydrate can be produced at a static type and near the clathrate hydrate production temperature.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows a hydrate generator using the heat storage tank of the present invention.

  In FIG. 1, a heat storage tank 10 in which a liquid guest substance and water as a host substance are accommodated is provided in a heat storage tank 10.

  The heat storage tank 10 is filled with a refrigerant 12 for cooling the heat storage body 11 or recovering cold heat, and the refrigerant 12 is cooled by the main refrigerator 13. In addition, although not shown, the cold energy recovered from the heat storage body 11 into the refrigerant 12 is supplied to the cold energy utilization system via a heat transfer coil installed in the tank or a heat exchanger installed outside the tank. Yes.

  The heat accumulator 11 is constituted by a multi-tube collecting pipe in which a heat transfer pipe 17 is connected between an upper header pipe 15 and a lower header pipe 16 as shown in the figure.

  FIG. 2 is a perspective view of the heat storage body 11 composed of a multi-tube collecting tube, and a plurality of upper and lower header tubes 15 and 16 are provided in accordance with the size of the heat storage tank 10 and a heat transfer tube 17 is connected. Furthermore, the headers 15 and 16 are connected by a connecting pipe 19 to constitute a heat storage body 11 composed of a multi-tube collecting pipe.

  In the heat storage body 11, for example, a supercooling section 18 is provided in the upper header pipe 15 of the multi-tube collecting pipe, and the supercooling section 18 is controlled by the sub refrigerator 20.

  The supercooling section 18 includes a cooling coil 18a through which a refrigerant flows as shown in FIG. 4A and a thermoelectric element 18b such as a Peltier element as shown in FIG. 4B. When the thermoelectric element 18b is used, the sub refrigerator 20 is not necessary and is connected to a power source instead.

  The supercooling unit 18 cools the liquid guest material and the water, which is the host material, to a temperature at which clathrate hydrate is reliably generated.

Examples of guest substances used in the present invention include cyclic hydrocarbons such as cyclopentane and linear hydrocarbons such as pentane. In the case of cyclopentane (C ₅ H ₁₀ ), a hydrate is produced at a production temperature of about 7 ° C. under atmospheric pressure, but in order to actually produce a hydrate, −2 ° C. with respect to the production temperature. Hydrate is produced | generated by cooling above.

  The composition ratio of the guest substance and water is determined by the hydrate structure. In the case of cyclopentane, cyclopentane: water has a molar ratio of 1:17 (volume ratio of 1: 3.3, weight ratio). 1: 4.4) is a complete clathrate hydrate formation ratio, so if the ratio of cyclopentane is less than this, there is no extra guest substance when clathrate hydrate formation is completed. If the amount is too small, the clathrate hydrate content is small and the performance of the heat storage density deteriorates. Therefore, the composition range is from 1:17 to about 3-fold dilution thereof.

  Further, about 5 wt% of a surfactant may be mixed in the guest substance and water, and this may be stirred to obtain a dispersion.

  Next, the hydrate production | generation method using this collecting pipe type thermal storage tank is demonstrated.

  When the clathrate hydrate of the liquid guest material in the heat storage body 11 and the water as the host material is generated, the refrigerant 12 in the heat storage tank 10 is introduced into the main refrigerator 13 and cooled, Is circulated in the heat storage tank 10.

  As a result, the liquid guest material and water as the host material in the heat storage body 11 are cooled to a temperature slightly lower than the clathrate hydrate formation temperature, and are brought into a supercooled state.

  After cooling the liquid guest material and the water that is the host material in the heat storage body 11 to this supercooled state, the supercooling unit 18 further cools the liquid guest material and the water that is the host material, A clathrate hydrate seed is formed around the cooling section 18. By forming the seed in this manner, the liquid guest substance and water cooled to the supercooled state can be hydrated as a whole by propagation of hydrate formation based on the seed. .

  As described above, when a clathrate hydrate is produced using cyclopentane as a guest substance, the production temperature of the hydrate is about 7 ° C., and the heat storage body 11 is slightly lower than 7 ° C. 5 In this state of cooling to ˜3 ° C., cyclopentane and water are kept in a supercooled liquid state with respect to the production temperature (about 7 ° C.).

  In this state, the sub refrigerator 20 is turned on, and the supercooling unit 18 cools the surrounding supercooled liquid to near −6 ° C., so that the supercooled water becomes ice, and this ice is used as a seed. A seed of clathrate hydrate is formed, and hydrate formation is propagated based on the seed, and clathrate hydrate is generated between the liquid guest material in the heat storage body 11 and water as the host material. .

  Due to the generation of the clathrate hydrate, the supercooling is released and the clathrate hydrate is raised to the production temperature, so the sub refrigerator 20 is turned off, and then the clathrate hydrate is generated in the main refrigerator 13. Can continue. The sub refrigerator 20 may be turned on before the completion of the operation of supercooling all substances in the heat storage body 11 to the clathrate hydrate generation temperature.

  As described above, in the production of clathrate hydrate using a liquid as a guest material, the present invention accommodates the liquid guest material and water as a host material in the heat storage body 11 in the heat storage tank 10, It is possible to produce a clathrate hydrate in a static type by simply cooling the refrigerant 12.

  In addition, after the clathrate hydrate is generated, the refrigerant 12 in the heat storage tank 10 may be used after being transferred to the cold heat utilization system, or the clathrate hydrate in the heat storage body 11 is directly utilized. You may make it transfer to.

  FIG. 3 shows another embodiment of the present invention.

  In this embodiment, the circulation line 22 and the circulation pump 23 are connected to the upper header pipe 15 of the multi-pipe collecting pipe constituting the heat storage body 11 provided with the supercooling section 18, and the inside of the upper header pipe 15 is connected. A liquid guest substance and water are repeatedly circulated in the supercooling section 18 so that the clathrate hydrate can be efficiently generated.

  Further, as indicated by the two-dot chain line, the upper header pipe 15 and the lower header pipe 16 are connected by a circulation line 24 so that a clathrate hydrate can be generated by circulating a liquid guest substance and water throughout. Is.

  In this embodiment, even if the liquid guest substance and water are not dispersed with the surfactant, the liquid guest substance and water are circulated even when they are separated into two layers, thereby enabling the packaging. It is possible to efficiently produce the wet hydrate.

It is a figure which shows one embodiment of this invention. It is a perspective view of the thermal storage body which consists of a multitubular collecting pipe in FIG. It is a figure which shows other embodiment of this invention. It is a figure which shows the detail of a supercooling part in this invention. It is a figure which shows the temperature change of a refrigerant | coolant and a thermal storage material when water is cancelled | released and ice produces | generates and this becomes seed | species and clathrate hydrate production | generation progresses. It is a figure which shows the temperature change of a refrigerant | coolant and heat storage material at the time of clathrate hydrate production | generation progressing by adding a hydrate to a heat storage material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thermal storage tank 11 Thermal storage body 12 Refrigerant 13 Main refrigerator 18 Supercooling part

Claims (7)

The liquid guest material and the host material water are accommodated in the heat accumulator , the heat accumulator is accommodated in the heat accumulator, the refrigerant is filled in the heat accumulator and the refrigerant is cooled by the main cooler, When generating clathrate hydrate with the guest substance and water in the heat storage body, the heat storage body is composed of a multi-tube collecting pipe in which a heat transfer pipe is connected between the upper header pipe and the lower header pipe, and the heat storage body An upper cooling pipe is provided with a supercooling section, and the heat storage body is supercooled to a temperature lower by about −2 ° C. than the production temperature of clathrate hydrate with the refrigerant. The guest material and water are supercooled to a temperature lower than the temperature of the refrigerant to form a clathrate hydrate seed, and the hydrate formation is propagated from the upper header pipe to the lower header pipe based on the seed. A clathrate hydrate is produced to produce a hydrate using a heat storage tank.   A method for producing a hydrate using a heat storage tank according to claim 1, wherein a surfactant is mixed into a liquid guest substance and water to form a dispersion, and the dispersion is accommodated in a heat storage body. The hydrate production | generation method using the thermal storage tank of Claim 1 or 2 which was made to circulate the guest substance and water in the upper header pipe | tube of the said thermal storage body to the said supercooling part.   The method for producing a hydrate using a heat storage tank according to any one of claims 1 to 3, wherein the supercooling section comprises a cooling coil or a thermoelectric element through which a refrigerant flows. The liquid guest material and the host material water are accommodated in the heat accumulator, the heat accumulator is accommodated in the heat accumulator, the refrigerant is filled in the heat accumulator and the refrigerant is cooled by the main cooler, In a hydrate generating device using a heat storage tank that generates clathrate hydrate with a guest substance and water in a heat storage body, the heat storage body is a multi-tube in which a heat transfer tube is connected between an upper header tube and a lower header tube A main refrigerator that supercools the heat storage body at a temperature lower by about −2 ° C. than the production temperature of the clathrate hydrate is provided in the heat storage tank. Hydrate using a heat storage tank, characterized in that a supercooling section is provided in the upper header tube of the heat storage body to form a clathrate hydrate seed by supercooling to a temperature lower than the temperature of the refrigerant. Generator. The hydrate production | generation apparatus using the thermal storage tank of Claim 5 which connected the circulation line which circulates the guest substance and water of the liquid in the upper header pipe | tube to the said supercooling part to the said upper header pipe | tube . The hydrate production | generation apparatus using the thermal storage tank of Claim 5 or 6 which a supercooling part consists of a cooling coil or a thermoelectric element with which a refrigerant | coolant flows.

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