JP2813912B2 - Water-containing cold storage material and its cold storage method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water-containing cold storage material for storing cold heat and a method for storing the same, and particularly to a water-containing cold storage material for storing cold as a solid-liquid dispersion in a cold storage state It relates to a cold storage method.

[Conventional technology]

Conventionally, as a regenerator material, a latent heat regenerator material using ice or a solidified organic compound, and a sensible heat regenerator material using a metal or an inorganic substance are well known. However, these conventional cold storage materials
The sensible heat type has a low regenerative storage capacity, while the latent heat type has a temperature of about 0 ° C., such as water-ice, which makes it difficult to apply it to a wide range of cold storage.

Further, most of the conventional cold storage materials have a non-flowable cold storage state, but a cool storage material in the form of slurry has also been proposed.

In this case, by accumulating with a water-ice slurry, even if a freezing point depressing substance is added, it is only possible to use the cold storage heat at around 0 ° C., and it is difficult to apply to lower temperatures. Some have been made.

For example, Japanese Patent Application Laid-Open No. 63-202687 proposes a cold storage agent for storing cold in a solid-liquid dispersion state comprising an oil continuous phase, a dispersed phase accompanied by solid-liquid change in the oil, and an emulsifier and / or an emulsion stabilizer. I have. However, in this case, the use of an emulsifier and an emulsion stabilizer increases the cost, and it is necessary to control the concentration and the like in order to secure the stability of the liquid-liquid dispersion as a cold storage material, and handling is not easy.

Further, the present invention proposes a mixture of a lower hydrocarbon having 3 to 12 carbon atoms having a melting point of −50 ° C. or less and an oxygen-containing organic compound having 1 to 6 carbon atoms, which is proposed in Japanese Patent Application No. 1-106844, The cold storage material, one of which is solid particles at low temperature, is 0 ° C or less,
It can be used at lower temperatures, but it is difficult to increase the amount of cold storage heat because the amount of latent heat of fusion used is small.

Further, Japanese Patent Application Laid-Open No. 62-62192 proposes a cold storage method using lower alcohols, acetone, or the like.
In the cold storage state, a relatively large ice block floats in the liquid, so that the transfer operation is difficult.

[Problems to be solved by the invention]

In view of the above-mentioned prior art, the present invention is a cold storage material that can be used even at a low temperature of 0 ° C. or less, particularly −15 ° C. or less, and even −40 ° C. or less, and has a sufficiently large cold storage capacity, and is safe and easy to handle. The purpose of the present invention is to provide a cold storage material.

[Means for solving the problem]

According to the present invention, 60 to 5% by weight of water and methanol or a carbonyl group having 1 to 5 carbon atoms having a melting point of -15
A water-containing cold storage material comprising a mixture of one or two or more organic compounds having a temperature of not more than 0 ° C., wherein solid particles having an average particle size of not more than 3.0 mm are dispersed in a solid-liquid state in a cold storage state.

Further, there is provided a water-containing cold storage material, wherein the cold storage material further contains a water-soluble organic compound or inorganic compound.

Further, a water-containing cold storage material comprising a mixture of 60 to 5% by weight of water and one or two or more of methanol or an organic compound having 1 to 5 carbon atoms and having a carbonyl group and having a melting point of -15 ° C or lower is stirred. The present invention provides a regenerative method characterized by cooling to -15 ° C or lower under cooling or flowing to produce and disperse solid particles having an average particle size of 3.0 mm or less, and to store the solid particles in a solid-liquid dispersion state.

 The present invention will be described in detail below.

The water-containing cold storage material of the present invention is a mixture of water and one or more of the following organic compounds, and has a water content of 60 to 5% by weight, preferably 50 to 10% by weight. 60% by weight water content
If the temperature exceeds the limit, the viscosity of the solid-liquid dispersion becomes high in the cold storage state, which makes it difficult to handle as a fluid, which is not preferable. On the other hand, if it is less than 5% by weight, the amount of cold storage heat is undesirably small.

The organic compound used as a mixture with water constituting the water-containing storage material of the present invention is methanol or an organic compound having a carbonyl group having 1 to 5 carbon atoms and having a melting point of -15 ° C or lower. Examples of the organic compound having a carbonyl group having 1 to 5 carbon atoms include ketones such as acetone, methyl ethyl ketone, and isopropyl methyl ketone. Further, other than methanol, alcohols such as isopropanol and t-butanol may be used.

Each of these organic compounds has a certain solubility and good compatibility with water, and is stably maintained as a liquid-liquid dispersion mixture at an arbitrary composition ratio within the range of the water content of the water-containing cold storage material of the present invention. Can be. Furthermore, it has the effect of lowering the freezing point of water when mixed with water, and those having high solubility greatly lower the freezing point of water. Therefore, cold heat can be stored at a temperature lower than 0 ° C.

Further, depending on the type of the organic compound, it is possible to form a eutectic with water to solidify and form solid particles in a cold storage state. In this case, the cold storage solid-liquid dispersion can be further stabilized.

In addition, the organic compound can control the surface energy of solid particles in the cold storage state by surface tension and electric action, suppress particle aggregation, and reduce solid particles having a small particle size and a relatively small particle size distribution. It stably generates and stabilizes the dispersion of solid particles in a cold storage state, and has an excellent effect in handling such as transfer. Furthermore, at the time of cold storage,
This has the effect of significantly reducing solid adhesion to the cooling surface, improving cooling efficiency, and stably generating solid particles.

The organic compound in the present invention may be appropriately selected from the above organic compounds in accordance with the intended cold storage conditions and the like.

In the hydrated cold storage material of the present invention, solid particles having an average particle diameter of 3.0 mm or less are kept in a solid-liquid dispersion state in the cold storage state. The smaller the average particle size of the solid particles, the more preferable the regenerative material for dispersing and maintaining the particles, in general, as it tends to fluidize.
The average particle size of the solid particles that are dispersed and maintained varies greatly depending on the composition of the cold storage material and the cold storage conditions, particularly the cold storage device.
If the average particle diameter of the solid particles exceeds 3.0 mm, it becomes difficult to handle the solid particles, which is not preferable. As described above, the solid particles usually contain water and, depending on conditions, the above-mentioned organic compound, depending on the cold storage temperature and the organic compound used, and the solid-liquid dispersion is stably maintained.

Further, since the average particle diameter of the solid particles in the cold storage state is 3.0 mm or less, the slurry can be easily handled as a slurry, and can be easily transported using an ordinary slurry transfer device.

In the cold storage material of the present invention, solid particles generated during cold storage have sedimentation properties due to a difference in specific gravity.For example, solid particles in a generated and dispersed state are separated and concentrated by a normal solid-liquid separation device such as a cyclone or a thickener. In addition, it is possible to easily obtain one with an increased amount of cold storage heat. Therefore, in the present invention, a large amount of cold heat with a small capacity can be handled at the time of cold heat utilization or cold storage.

In the cold storage method of the present invention, in order to store cold heat using the above-mentioned water-containing cold storage material, the cold storage material is introduced into a cooling tank provided with a stirrer, and the cold storage material is rotated and stirred at a normal rotation speed of 10 to 1500 rpm. By cooling to −15 ° C. or less, solid particles containing water having an average particle size of 3.0 mm or less are generated, and the regenerator material can be converted to a regenerative state as a solid-liquid dispersion. In this case, if the rotation speed is less than 10 rpm, the solid particle diameter becomes large, and it is difficult to handle as a fluid. If the rotation speed exceeds 1500 rpm, the gas is entrained and the cooling efficiency decreases, which is not preferable.

In addition, as a method of cooling the regenerator material under flow, for example, using a pump, the regenerator material is introduced in a tangential direction into a cooling tank having a structure such as a tank or a cyclone at a flow rate of about 5 cm / sec or more of the regenerator material. There is a method of cooling from the outer surface. In this case, when the introduction speed of the regenerator material is lower than 5 cm / sec, the solid particle diameter may increase, making it difficult to handle as a fluid. Driving may be hindered. As another method of cooling the regenerator material using a pump while flowing, there is also a method of externally cooling the regenerator material while passing the regenerator material in a turbulent state in the pipe by the discharge pressure of the pump.

In the cold storage method of the present invention, the cooling is performed, for example, by arranging a cooling pipe through which the cooling medium flows in the cooling tank, or by forming the outer surface of the cooling tank as a double ring, allowing the cooling medium to flow through the outer ring, Cooling heat exchange can be performed. The cooling medium may be a known cooling medium, and may be in any state of gas, liquid, or a mixture of gas and liquid. For example, LNG
LNG can be used to store cold energy of LNG.

In the cold storage of the present invention, since a mixture of the above organic compound and water is used as a cold storage material, glass, stainless steel, aluminum, even if a normal device material such as iron is used as a material of a cooling device such as a cooling layer, Adhesion of generated solid particles to a cooling surface or the like can be suppressed.

The water-containing cold storage material of the present invention can further contain a water-soluble organic compound and / or an inorganic compound as the third component.

Examples of the water-soluble organic compound include water-soluble oxygen-containing organic compounds such as ethylene glycol, triethylene glycol, polyethylene glycol, ethanol, ethanol, acetone, and ethanolamine. In this case, as the water-soluble organic compound of the third component, a compound different from the above-mentioned methanol or an organic compound having a carbonyl group having 1 to 5 carbon atoms used in a mixture with water is used.

Examples of the water-soluble inorganic compound include sulfates such as Na ₂ SO ₄ , chlorides such as KCl and NaCl, nitrates such as NaNO ₃ , and (NH ₄ ) ₂ C
Carbonates such as O ₃ and K ₂ CO ₃ ; and phosphates such as K ₃ PO ₃ .

One or more of these third components of the water-soluble organic compound and / or inorganic compound can be used,
In the cold storage material of the present invention, the content thereof is 0.
It is preferable to add 005 or more. The above ratio is
No effect is observed below 0.005.

The moisture content of the water-containing cold storage material containing the third component is also set to 60 to 5% by weight, similarly to the above-mentioned two-component water-containing cold storage material.

The water-containing cold storage material of the present invention comprising water, methanol or an organic compound having a carbonyl group having 1 to 5 carbon atoms and having a melting point of -15 ° C or lower and the third component has various degrees of freezing point depression of water. Depending on the cold temperature range used for cold storage, it is possible to freely select a wide range of hydrated cold storage materials by appropriately selecting a combination of the three components.

The present invention is configured as described above, has a high cold storage capacity by using water having a large latent heat of fusion, and uses methanol or an organic compound having a carbonyl group having 1 to 5 carbon atoms, a water-soluble organic compound or / and an inorganic compound. By selecting, it is possible to widely store and use cold energy at a low temperature of 0 ° C or less, store cold energy of LNG and LPG that had been left unconventional, and have low risk of ignition and low stability. A high cold storage material can be obtained. Further, in the cold storage state, the solid-liquid dispersion is a solid-liquid dispersion in which small solid particles are stably dispersed without agglomeration of solid particles, and can be transferred and easily handled. Furthermore, it does not adhere to the cooling surface during cold storage,
Further, a solid-liquid dispersion can be obtained without aggregation.

The cold storage material of the present invention can be used as a cold heat source as it is in a cold storage state, or as a cold storage medium by enclosing the cold storage material in a container or passing through a cooling heat transfer tube or the like. In addition, since it can store cold in the low-temperature range of -15 ° C or less, it can be used as a back-up for low-temperature warehouses such as fish and shellfish and refrigerators, and as a cooling source for cooling systems. It can be used for preservation of related cells, etc., and its use is not limited.

〔Example〕

Example 1 150 g of a cold storage material obtained by mixing 40% by weight of water and 60% by weight of acetone was provided with a cooling heat transfer tube in a cooling tank with an inner diameter of 40 mmφ equipped with a stirrer, and further cooled the outer surface. At the same time, put it in a cooling tank that can heat the heater, and use liquid nitrogen and a heater.
It was cooled and stored at 90 ° C. The stirring operation at this time is a rotation speed of 500r
pm.

During this cold storage operation, solid particles were generated at around −30 ° C., and finally a cold storage state of the solid-liquid dispersion cooled at −90 ° C. was obtained. No solid particles adhered to the cooling heat transfer tube surface.

The obtained cold storage material is a solid-liquid dispersion in which solid particles having an average particle diameter of 0.3 mm are dispersed, and the shear rate is measured by a rotational viscometer.
The viscosity measured at 60 to 150 sec ^-1 was as low as 20 centipoise or less, and at higher shear rates the viscosity was further reduced and could be pumped. The solid particles exhibited slow sedimentation.

Example 2 150 g of a cold storage material obtained by mixing 50% by weight of water and 50% by weight of acetone can be subjected to a cold storage operation at -80 ° C in the same manner as in Example 1 to be stored as a solid-liquid dispersion. Was. Also,
No solid particles adhered to the cooling heat transfer tube surface.

Example 3 A cold storage operation was performed at −40 ° C. in the same manner as in Example 1 using a cold storage material having the same composition as in Example 2. There was no solid attached to the heat transfer surface, and cold storage was possible as a solid-liquid dispersion.

The viscosity was slightly lower than that obtained in Example 2.

Example 4 150 g of a cold storage material obtained by mixing 30% by weight of water and 70% by weight of methyl ethyl ketone were treated at -80 ° C in the same manner as in Example 1.
The cold storage operation was performed.

As a result, solid particles were generated at around −30 ° C., and finally, a cold storage state of the solid-liquid dispersion cooled at −80 ° C. was obtained.
The obtained cold storage material was a solid-liquid dispersion in which solid particles having an average particle diameter of 0.8 mm were dispersed, and had a viscosity of 70 centipoise or less and a higher viscosity than that of the cold storage material obtained in Example 1. Could be transferred.

Example 5 A cold storage material obtained by mixing 40% by weight of water and 60% by weight of methanol was subjected to a cold storage operation at -90 ° C in the same manner as in Example 1 to obtain a solid-liquid dispersion at -90 ° C. A cool storage condition was obtained.

Example 6 Water 30% by weight, ethylene glycol 15% by weight, acetone
Example 1 was obtained by mixing 150 g of the cold storage material obtained by mixing with 55% by weight.
The cold storage operation was performed at -90 ° C in the same manner as described above.

As a result, after solid particles were generated at around -70 ° C, a cold storage material in a cold storage state of a solid-liquid dispersion at -90 ° C was finally obtained. Same as wood.

Example 7 150 g of a cold storage material obtained by mixing 55% by weight of water, 15% by weight of acetone and 35% by weight of methanol were subjected to a cold storage operation at -90 ° C in the same manner as in Example 1.

As a result, after solid particles were generated at around −40 ° C., cooling was further continued to obtain a regenerator material stored at −90 ° C. No solid adhesion was observed on the surface of the cooling heat transfer tube during cold storage. The average particle size of the individual particles of the obtained regenerator material is about 0.
It was 1 mm or less and the sedimentation was very low. Also,
It had a viscosity that could be transferred by a pump.

Example 8 150 g of a cold storage material obtained by mixing 55% by weight of water, 35% by weight of acetone and 15% by weight of ethanol were subjected to a cold storage operation at -70 ° C in the same manner as in Example 1.

As a result, after solid particles were generated at around −30 ° C., cooling was continued to obtain a regenerator material stored at −70 ° C. The obtained regenerator material had a considerably low sedimentation property as in Example 7, and had a viscosity that could be transferred by a pump.

Example 9 150 g of a cold storage material obtained by mixing 55% by weight of water, 30% by weight of acetone and 30% by weight of ethanol were subjected to a cold storage operation at -90 ° C in the same manner as in Example 1.

As a result, after solid particles were generated at around −50 ° C., cooling was further continued to obtain a regenerator material stored at −90 ° C. No solid adhered to the cooling heat transfer tube surface during cold storage. The obtained regenerator material had a viscosity that allowed it to be transferred by a pump, as in Examples 7 and 8.

〔The invention's effect〕

The regenerator material and the regenerator method of the present invention can select the regenerative temperature in a wide low temperature range of 0 ° C. or less, have a high regenerative capacity, and have a regenerative state of a solid-liquid dispersion, which can be transferred as a slurry and handled. It is simple.

The cold storage material of the present invention is a mixture with water, which has a low degree of danger and is safe.In addition, cold storage is easy and economical, and cold energy of LNG and LPG can also be stored, which is extremely useful in industry. It is.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayoshi Hiramatsu 1 at 20 Kitakanyama, Odaka-cho, Midori-ku, Nagoya-shi, Aichi Prefecture Electric Power Technology Research Laboratory, Chubu Electric Power Co., Inc. (72) Inventor Hirotoshi Yamada Aichi 20 in Kita-Sekiyama, Odaka-cho, Midori-ku, Nagoya-city, Chubu Electric Power Co., Inc. Inside the Power Technology Research Laboratory (72) Inventor Masayoshi Ioka 142-2-2 Hakusan-cho, Midori-ku, Yokohama-shi, Kanagawa (72) Invention Person Kazushige Kawamura 2-89-646 Asahi-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Eiji Awai 6-20-510, Shinshironakamachi, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture 510 (56) References JP-A-3-174485 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C09K 5/00 WPI / L (QUESTEL)

Claims (4)

(57) [Claims] 1. A cold storage state comprising a mixture of 60 to 5% by weight of water and one or two or more of methanol or an organic compound having 1 to 5 carbon atoms and having a carbonyl group and having a melting point of -15 ° C. or lower. Wherein the solid particles having an average particle diameter of 3.0 mm or less are dispersed in a solid-liquid state. 2. The water-containing cold storage material according to claim 1, wherein said cold storage material further contains a water-soluble organic compound or inorganic compound. 3. A water-containing cold storage material comprising a mixture of 60 to 5% by weight of water and one or more of methanol or an organic compound having 1 to 5 carbon atoms and having a carbonyl group and having a melting point of -15 ° C. or lower. Is cooled to −15 ° C. or less under stirring or flowing to produce and disperse solid particles having an average particle size of 3.0 mm or less, and to cool the solid in a solid-liquid dispersion state. 4. The method according to claim 3, wherein said cold storage material further contains a water-soluble organic compound or inorganic compound.