JP2011212545A - Gas/liquid separation membrane for coolant, gas/liquid separation module for coolant and gas/liquid separation method for coolant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas/liquid separation membrane for coolants capable of separating a coolant in a gas/liquid coexisting state into a gas and a liquid, at high efficiency.SOLUTION: The gas/liquid separation membrane for coolants includes fine pores. The pitch of the fine pores is 30-1,000 nm; the diameters of the fine pores are 10-300 nm; the thickness of the gas/liquid separation membrane is 30-1,000 nm; and the standard deviation in the distribution of diameters of the fine pores is equal to or smaller than 30% of the average.

Description

  The present invention relates to a gas-liquid separation membrane for refrigerant used for separating gas and liquid from a gas-liquid coexisting refrigerant.

  Conventionally, various methods have been used to separate a gas and a liquid from a medium (for example, a refrigerant) in a gas-liquid coexistence state (collectively referred to as “gas-liquid mixing” or “gas-liquid two-phase” state). Proposed.

  For example, the refrigerant used in the refrigeration apparatus exists in a state in which liquid, gas, and gas-liquid coexist. The gas-liquid separator for separating liquid and gas from the coexisting state of gas and liquid is a tank that collects liquid by gravity or a liquid phase that adheres to the outer wall by centrifugal force of swirling flow and collects liquid by gravity. A liquid separator or the like is used (see Patent Document 1).

  Since the gas-liquid separator having such a structure basically has a structure in which a liquid phase having a higher density than the gas phase is separated by a volume force such as gravity and centrifugal force, these gas-liquid separators are It is necessary to devise such as matching the installation direction and the gravity direction so that the body force is dominant, or generating a flow with acceleration such as a swirling flow or a bending flow. For this reason, in addition to a small degree of freedom in the installation position and orientation of the gas-liquid separator, these apparatuses are increased in size to use the tank and the swirl flow generator.

  However, even when such a large apparatus is used, a spray flow in which liquid mist is mixed in the gas phase is generated, and a sufficient gas-liquid separation effect may not be obtained.

  In order to solve this problem, it has been proposed to use a gas permeable filter to separate a gaseous refrigerant (also referred to as “gas refrigerant”) from a gas-liquid coexisting refrigerant in a gas-liquid separator. (See Patent Document 2).

  However, when using a conventional filter, the fine filter has a large gas-phase passage resistance (pressure loss), so the processing efficiency is poor, and the coarse filter has a sufficient gas-liquid separation effect. It was not obtained.

JP 2001-235245 A JP 2009-133666 A

  As described above, efficient gas-liquid separation is difficult with the conventional gas-liquid separator for refrigerant. An object of the present invention is to provide a high-performance gas-liquid separation membrane for refrigerant capable of separating a gas-liquid coexisting refrigerant into gas and liquid with high efficiency.

  As a result of intensive studies to solve the above problems, the present inventor is able to efficiently separate a refrigerant in a gas-liquid coexistence state into a gas and a liquid by the refrigerant-liquid separation membrane for a pore having a very narrow pore size distribution. As a result, the present invention has been completed.

  That is, the present invention provides the following gas-liquid separation membrane for refrigerant and its manufacturing method, gas-liquid separation membrane laminate for refrigerant and its manufacturing method, gas-liquid separation membrane module for refrigerant, and gas-liquid separation method of gas-liquid mixed refrigerant It is about.

  [1] A gas-liquid separation membrane for refrigerant having pores, the pore pitch of the pores being 30 to 1000 nm, the pore diameter of the pores being 10 to 300 nm, A gas-liquid separation membrane for refrigerants having a thickness of 30 to 1000 nm and a standard deviation in the pore size distribution of the pores of 30% or less of the average value.

[2] The above-mentioned [1], including the step of transferring the unevenness of the first mold having the recesses made of pores to the second template, and the step of transferring the unevenness of the second template to the film made of the polymer ] The manufacturing method of the gas-liquid separation membrane for refrigerant | coolants described in the above.

  [3] The manufacturing method according to the above [2], wherein the first mold having the concave portion formed of the pores is produced by anodizing an aluminum plate.

[4] A step of transferring the unevenness of the third mold having the protrusions made of protrusions to the first mold,
The refrigerant gas-liquid separation according to the above [1], including a step of transferring the irregularities of the first template to a second template, and a step of transferring the irregularities of the second template to a film made of a polymer. A method for producing a membrane.

  [5] The manufacturing method according to [4], wherein the third mold having the protrusions including the protrusions is produced by developing the photoresist layer stacked on the substrate by interference exposure.

  [6] A gas-liquid separation membrane laminate for cold multiplication, which is formed by laminating the gas-liquid separation membrane for refrigerant according to [1] above and a porous film substrate.

[7] The step of laminating the gas contact film for refrigerant and the porous film substrate according to [1] above, and melting the gas contact film for refrigerant and / or the porous film substrate by heating The manufacturing method of the gas contact film laminated body for refrigerant | coolants including the process of fuse | melting both.

  [8] A container whose internal space is separated into a first space and a second space by the refrigerant gas-liquid separation membrane according to [1] or the refrigerant gas-liquid separation membrane laminate according to [6]. And a gas-liquid separation membrane module for refrigerant having a gas-liquid two-phase flow liquid inlet and a liquid-phase outlet from the external space in the first space and a gas-phase outlet to the external space in the second space .

  [9] A refrigerant in a gas-liquid coexistence state is introduced from the gas-liquid two-phase flow liquid inlet of the gas-liquid separation membrane module for refrigerant according to [8], and a liquid-phase refrigerant is taken out from the liquid phase outlet; A gas-liquid separation method for a refrigerant, comprising a step of separating a gas-liquid coexisting refrigerant into a liquid phase and a gas phase by taking out the gas-phase refrigerant from the gas-phase outlet.

  The gas-liquid separation membrane for refrigerant of the present invention has a small pore size distribution and can gas-liquid-separate a gas-liquid coexisting refrigerant into gas and liquid with higher efficiency.

It is a cross-sectional schematic diagram which shows the one aspect | mode of the gas-liquid separation membrane for refrigerant | coolants of this invention. It is process drawing which produces the casting_mold | template which consists of anodized porous alumina which has the recessed part which consists of pores. It is process drawing which transfers the unevenness | corrugation of the 3rd casting_mold | template which has the convex part which consists of protrusions to a 1st casting_mold | template. It is process drawing which shows an example which produces the gas-liquid separation membrane for refrigeration cycles from the 1st casting_mold | template which has the recessed part which consists of pores. 3 is a schematic cross-sectional view showing a module used in Examples 1 and 2. FIG. It is a cross-sectional schematic diagram which shows the module used in Comparative Examples 1 and 2. It is an external view of the gas-liquid separation membrane module for refrigerant | coolants of this invention. It is a schematic block diagram of the refrigerating cycle to which the gas-liquid separation membrane module for refrigerant | coolants of this invention is applied. It is a schematic block diagram of the gas-liquid separation performance evaluation system used by the Example and the comparative example.

Hereinafter, the present invention will be described in detail.
The gas-liquid separation membrane for refrigerant of the present invention has pores, the pore pitch of the pores is 30 to 1000 nm, the pore diameter of the pores is 10 to 300 nm, and the thickness of the gas-liquid separation membrane And a standard deviation in the pore size distribution of the pores is 30% or less of the average value. In addition, the pore in this invention means the hole which has a fine dimension about 10-300 nm in diameter.

  The gas-liquid separation membrane for refrigerant according to the present invention has high efficiency by disposing a gas-liquid coexisting refrigerant on one side, allowing gas-liquid separation through the pores of the membrane, and taking out only the gas-like refrigerant from the other side. The refrigerant in the coexisting state of gas and liquid can be separated into gas and liquid.

  First, it will be described how a filter-like membrane having fine vent holes functions as a gas-liquid separation membrane. Generally, a liquid has a surface tension, and a capillary force is generated along with this. Capillary force works stronger as the hole or tube becomes narrower, and also works in the air vent, so that the passage of liquid in the air vent is blocked. On the other hand, although the flow of gas is inhibited in inverse proportion to the cross-sectional area of the vent hole, the gas is allowed to pass therethrough, and the flow is not blocked like a liquid. As a result, a filter-like membrane having fine vent holes functions as a gas-liquid separation membrane.

  The capillary force is determined by the contact angle of the liquid in the vicinity of the vent hole and the hole diameter of the vent hole. When the pore size distribution is large, the force that opposes the pressure when separating the gas and liquid theoretically depends on the largest pore size. Further, since the air holes in many conventional gas-liquid separation membranes are connected to each other, these air holes induce the passage of liquid.

  Such a gas-liquid separation membrane is also required to have a function of allowing gas to pass through quickly. The size of the ventilation hole and the gas passage resistance are generally expressed by the Hagenpo Azuille equation. If the pore size distribution occurs in the direction in which the pore size of the air holes (pores) decreases, the gas passage efficiency decreases. That is, a gas-liquid separation membrane using capillary force has higher performance and reliability as the pore diameter is uniform.

  In the case of the gas-liquid separation membrane for refrigerant of the present invention, the standard deviation in the pore size distribution of the pores is 30% or less of the average value, preferably 20% or less, more preferably 10% or less. .

  In addition, since the surface of the gas-liquid separation membrane for refrigerant of the present invention has extremely high smoothness, local retention of the fluid in contact is reduced, and movement of bubbles on the refrigerant side in the coexisting state of gas-liquid is promoted, so that gas can pass efficiently. Can be done.

  Another aspect of the present invention is a gas / liquid separation membrane laminate for cold multiplication formed by laminating the gas-liquid separation membrane for refrigerant and a porous film substrate. Therefore, when the refrigerant gas-liquid separation membrane of the present invention is used as a refrigerant gas-liquid separation membrane laminate in which a smooth porous film base material is laminated, a gas-liquid coexisting refrigerant is allowed to flow to the gas-liquid separation membrane side. It is preferable because the gas-liquid separation efficiency is increased.

Hereinafter, preferred embodiments of a gas-liquid separation membrane for refrigerant of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing one embodiment of a thin film used in the gas-liquid separation membrane for refrigerant of the present invention. The pores of the gas-liquid separation membrane for refrigerant according to this aspect have a tapered shape in which the pore diameter increases from the front surface to the back surface of the thin film. When the refrigerant gas-liquid separation membrane of the present invention is produced by the production method described later, the refrigerant gas-liquid separation membrane is separated from the mold if the pore diameter is uniform from the front surface to the back surface of the refrigerant gas-liquid separation membrane. In the step of molding, the taper shape of this aspect is more preferable because the thin film cannot be smoothly peeled off and defects may occur.

Next, the manufacturing method of the thin film used for the gas-liquid separation membrane for refrigerant | coolants of this invention is demonstrated.
The first manufacturing method includes a step of transferring the unevenness of the first mold having a recess made of pores to a second template, and a step of transferring the unevenness of the second template to a film made of a polymer. It is a manufacturing method of the gas-liquid separation membrane for refrigerant | coolants. Here, the first mold can be preferably produced by, for example, anodizing an aluminum plate.

  The second manufacturing method includes a step of transferring the unevenness of the third mold having a protrusion made of a protrusion to the first mold, a step of transferring the unevenness of the first mold to the second template, and the second 2 is a manufacturing method of a gas-liquid separation membrane for refrigerant, which includes a step of transferring irregularities of the mold 2 to a membrane made of a polymer. Here, the third mold can be suitably produced, for example, by developing the photoresist layer laminated on the substrate by interference exposure.

  In the above two types of manufacturing methods, the first mold is a mold having a concave portion formed of pores as in the refrigerant gas-liquid separation membrane of the present invention. Further, the second mold and the third mold are molds having protrusions made of protrusions contrary to the gas-liquid separation membrane for refrigerant of the present invention, and the first mold has a positive and negative relationship. is there.

The first manufacturing method will be described in more detail.
FIG. 2 shows a method for producing a first mold (anodized porous alumina) having a recess made of pores. The anodized porous alumina 3 is formed on the surface of the aluminum substrate 2 by anodization. The pores 4 of the anodized porous alumina 3 have a cylindrical shape having a substantially constant diameter except for the bottom. If this is used as a mold as it is, the thin film cannot be smoothly peeled off from the mold, which may cause defects.

  On the other hand, a method of manufacturing a stamper for producing an antireflection film made of anodized porous alumina having a hole having a desired tapered shape by combining anodization and pore enlargement processing by etching is known (special feature). No. 2005-156695).

  Briefly describing the above method, after anodizing the aluminum substrate 2 for a predetermined time to form pores of a desired depth, the pore diameter is expanded by immersing in an appropriate acid solution. Do. Thereafter, anodization is performed again to form pores having a smaller pore diameter than in the first stage. By repeating this operation, anodized porous alumina having tapered pores can be obtained. By increasing the number of repeated steps, smoother tapered pores can be obtained. By adjusting the anodizing time and the pore diameter expansion processing time, it is possible to form pores having various tapered shapes, and by using this method for the production of a gas-liquid separation membrane for refrigerant, the pitch, It is considered that the optimum structural design of the gas-liquid separation membrane for refrigerant can be made according to the depth of the liquid.

  In addition, an anode having a high hole arrangement regularity is obtained by using anodized porous alumina prepared by anodizing at a constant voltage for a long time, once removing the oxide film, and again anodizing under the same conditions. It becomes possible to use oxidized porous alumina as a mold.

  As the anodized porous alumina to be used, for example, anodized porous alumina prepared using oxalic acid as an electrolytic solution at a conversion voltage of 30 V to 60 V can be used. Alternatively, anodized porous alumina produced using sulfuric acid as the electrolytic solution and at a conversion voltage of 25V to 30V can be used. By using such anodized porous alumina, it is possible to obtain a template having a dent array with higher regularity.

  Furthermore, in the preparation of anodized porous alumina, a fine depression can be formed on the aluminum surface prior to anodization, and this can be used as a pore generation point during anodization. A depression array having an arbitrary arrangement can be used as a template. It becomes possible to do.

  The second template can be obtained by filling the pores of the first template produced by the above method with a substance such as metal, metal oxide, or polymer, and then removing the first template.

Metals, metal oxides, but are not particularly limited, is generally Ni, Ta, SiO _2, carbon, organic SOG or the like is used. Among these examples, Ni is preferable because it is easily electroformed.

  In addition, the polymer filled in the first mold is not limited as long as it has processability, but a typical example is a fluororesin (polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkoxy). Ethylene trifluoride copolymer, tetrafluoroethylene-6-fluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, poly-trifluoroethylene chloride, polyvinylidene fluoride, polyvinyl fluoride, Teflon (registered trademark) ) AF (registered trademark: manufactured by DuPont), Hyflon AD (registered trademark: manufactured by Solvay Solexis), Cytop (registered trademark: manufactured by Asahi Glass)), acrylic resin, polycarbonate, polystyrene, polysulfone, polyethersulfone, polyvinyl alcohol , Ethylene / vinyl alcohol copolymer, cellulose Can polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyester, nylon, polyimide, polyamide, polyphenylene sulfide, polyarylate, and be given their copolymers. Further, after the polymer monomer is filled in the first mold, it may be polymerized by light such as UV and / or heat. Among these examples, the fluororesin is preferable because it is excellent in releasability from the first mold.

  Furthermore, a gas-liquid separation membrane for refrigerant can be obtained by filling the second template with a polymer and then releasing the polymer membrane from the second template.

The method for transferring the polymer to the second template is not particularly limited, and methods such as optical imprinting, thermal imprinting, room temperature imprinting, and nanocasting imprinting can be used.
The polymer is not particularly limited as long as it does not cause a problem due to adhesion or fusion with the material of the second mold when the second mold is filled. Ethylene, tetrafluoroethylene-perfluoroalkoxy trifluoride ethylene copolymer, tetrafluoroethylene-6 fluoropropylene copolymer, Teflon (registered trademark) AF, Hyflon AD (registered trademark), Cytop (registered trademark) ), Etc., polystyrene, polysulfone, polyethersulfone, polyethylene, polypropylene, polyphenylene sulfide, polyarylate, and copolymers thereof are preferred because of their high durability. Further, after the polymer monomer is filled in the second mold, it may be polymerized by light such as UV and / or heat. Among these examples, a fluororesin is more preferable because it is excellent in releasability from the second mold.

  When the volume of the polymer used for the transfer was larger than the volume of the concave / convex gap formed by the protrusions of the second mold, the pores on one side of the gas-liquid separation membrane for refrigerant were blocked with an extra remaining film Since it is in a state, it is necessary to remove the residual film by etching before or after releasing to form a through-opening thin film. Examples of the etching method include high vacuum dry etching using plasma, atmospheric pressure dry etching, wet etching using a solvent, and the like. Among these, atmospheric pressure dry etching is preferable because of low cost and high etching accuracy.

FIG. 4 shows an example of a process for producing a refrigerant gas-liquid separation membrane by the above steps.
A surface conductive layer made of Ni-P, Au, Cr or the like is formed on the surface of the first mold made of anodized porous alumina 3 by electroless plating or sputtering, and then the second mold is made by electrolytic plating of Ni or the like. Form. The second template is obtained by peeling the second template from the first template or selectively dissolving and removing the first template. Next, the second template is filled with a polymer, for example, a solution in which polysulfone is dissolved in a solvent, and the solvent is dried to obtain a thin film made of the polymer. After the polymer film filled in excess of this thin film is removed by plasma etching, it is peeled off from the second mold to obtain a gas-liquid separation film for refrigerant. By laminating the gas-liquid separation membrane for refrigerant and the porous film substrate, the gas-liquid separation membrane laminate for refrigerant of the present invention can be obtained.

Next, the second manufacturing method will be described in more detail.
FIG. 3 shows a method for producing a first mold having a concave portion made of a pore from a third mold having a convex portion made of a protrusion.

  The third mold can be suitably produced by an interference exposure method. First, a positive photoresist is applied on a smooth substrate 7 (for example, a polished glass master). A positive photoresist is a resist well known in the technical field of semiconductor device manufacturing, and is a composition containing a resin having a phenolic hydroxyl group and a photoacid generator. This composition has low solubility in an alkaline developer before light irradiation, but acid is generated by light irradiation and the solubility in an alkaline developer is increased. Patterning can be performed by utilizing the difference in solubility between the light irradiated portion and the light non-irradiated portion with respect to the developer. Hereinafter, the light non-irradiated part is also referred to as a cured part, and the light irradiated part is also referred to as an uncured part.

  Next, exposure is performed by an interference exposure method using laser light (hereinafter also referred to as “laser interference exposure method”) to obtain a hardened portion formed of fine tapered protrusions and a remaining uncured portion. After the exposure, development is performed to remove the uncured portion, thereby obtaining a third mold 9 having a convex portion 8 made of a protrusion.

  The convex portion 8 formed in the photoresist has a so-called tapered shape in which the top portion 8a of the convex portion is thinned and the bottom portion 8b is thickened by a laser interference exposure method. This phenomenon is such that the laser beam power intensity is strong on the photoresist surface and becomes weaker as it travels through the photoresist. As a result, the exposure amount increases on the photoresist surface and the top 8a is eroded, resulting in the depth of the photoresist. It is thought that this is because the exposure amount becomes smaller as the process proceeds in the vertical direction, the erosion in the depth direction becomes weaker, and the bottom surface portion 8b expands. Therefore, the taper angle can be adjusted according to the photosensitivity (γ value) of the photoresist.

  The laser interference exposure method is an exposure method using interference fringes formed by irradiating laser light of a specific wavelength from two directions of an angle θ ′, and is used by changing the angle θ ′. It is possible to obtain an uneven grating structure having various pitches within a range limited by the laser wavelength. For example, an uneven pattern composed of the above-mentioned tapered protrusions can be formed by overlapping and exposing three sets of the interference fringes whose directions are shifted by 120 degrees.

  Lasers that can be used for interference exposure are limited to TEM00 mode lasers. Examples of the ultraviolet laser capable of laser oscillation in the TEM00 mode include an argon laser (wavelengths 364 nm, 351 nm, and 333 nm), and a fourth harmonic wave (wavelength 266 nm) of a YAG laser.

  The taper angle can also be changed by etching the formed pattern. That is, in high vacuum plasma etching, the taper angle can be changed by controlling the anisotropy of etching.

  In general, the longer the mean free path of the incident reactive ions is made lower and the gas is vertically incident, the anisotropy increases. However, in this case, since the etching is uniformly performed in the vertical direction, the taper is tapered. The change in angle is small. On the other hand, by setting the pressure higher, the incidence of reactive ions in the lateral direction increases and etching is also performed in the lateral direction, thereby changing the taper angle.

  As shown in FIG. 3B, the surface casting layer is formed on the third mold produced by the above method, and then Ni electroforming is performed to form the first mold. When the third mold is removed, the first mold 10 having the transferred irregularities is obtained by reversing the irregularities (FIG. 3C).

  Using the first template produced by the above method, the hole is filled with a substance such as metal, metal oxide, or polymer, and then the first template is removed to obtain a second template. Can do.

  The second mold produced by the second production method is continuously filled with a polymer and released from the second mold in the same manner as the second mold produced by the first production method. In particular, it is possible to obtain a gas-liquid separation membrane for refrigerant that has a tapered shape in which the pore diameter changes and has a very small pore diameter distribution.

  According to the above manufacturing method, the pore pitch is 30 to 1000 nm, the pore diameter is 10 to 300 nm, the pore depth is 30 nm to 1000 nm, and the pore diameter distribution of the pore diameter is extremely narrow. A gas-liquid separation membrane for refrigerant can be obtained. The very small pore size distribution means that the standard deviation in the pore size distribution is not more than 30% of the average value, preferably not more than 20%, more preferably not more than 10%. Say.

  Further, the porosity of the refrigerant gas-liquid separation membrane of the present invention is not particularly limited, but is usually 25% or more and 95% or less, preferably 40% or more, more preferably 50% or more, and particularly preferably 60% or more. It is. If it is 25% or more, it is excellent in water permeability, and if it is 95% or less, sufficient strength used as a gas-liquid separation membrane for refrigerant can be secured.

  The refrigerant gas-liquid separation membrane obtained by the above production method can be used as it is, but it can be used as a refrigerant gas-liquid separation membrane laminate by laminating with a porous film substrate in order to increase mechanical strength. preferable. Examples of the porous film substrate include a microporous membrane, a nonwoven fabric, a phase separation membrane, and a stretched aperture membrane.

  The material of the porous film substrate is not particularly limited, but typical examples include polytetrafluoroethylene, tetrafluoroethylene-tetrafluoroalkoxy-trifluoroethylene copolymer, tetrafluoroethylene-6 fluoropolymer. Fluoropolymers such as propylene copolymer, Teflon (registered trademark) AF, Hyflon AD (registered trademark), Cytop (registered trademark), polystyrene, polysulfone, polyethersulfone, polyethylene, polypropylene, polyphenylene sulfide, polyarylate, and Those copolymers are preferred because of their high durability.

  The pore diameter of the porous film substrate is preferably larger than the pore diameter of the gas-liquid separation membrane for refrigerant, and more preferably in the range of 1 to 100 μm. In addition, the thickness of the porous film substrate is preferably 10 to 1000 μm in view of the balance between strength and porosity. The lamination of the gas-liquid separation membrane for refrigerant to the porous film substrate is generally performed by superimposing the gas-liquid separation membrane for refrigerant on the porous film substrate while peeling it from the mold. Etching may make it difficult to release the gas-liquid separation membrane for refrigerant from the mold. In this case, it is necessary to etch the remaining film after lamination. However, in the case of superposition by simple transfer, the remaining film is on the porous film substrate side, so that there is a problem that etching cannot be performed in a subsequent process. In order to prevent such a problem, it is necessary to transfer the substrate once to another substrate, turn it over, and then superimpose it on the porous film substrate. Since this another base material needs to re-attach the thin film peeled off from the metal mold to the porous film base material, it is preferably weakly adhesive.

  The gas-liquid separation membrane for refrigerant and the porous film can be used simply by being overlapped, but may be heat-sealed and / or bonded with an adhesive. In the case of heat fusion, the gas-liquid separation membrane for refrigerant and / or the porous film substrate is melted by heating to fuse them together. At this time, when the melting temperature of the material constituting the porous film substrate is lower than the melting temperature of the material constituting the refrigerant gas-liquid separation membrane, the pore shape of the refrigerant gas-liquid separation membrane is reduced during heat fusion. This is more preferable because the influence of is less. Examples of the heating method in the case of heat fusion include methods such as applying a heating plate, applying hot air, and irradiating infrared rays and / or high frequencies.

  Another aspect of the present invention is the following gas-liquid separation membrane module for refrigerant, including the gas-liquid separation membrane for refrigerant and / or the gas-liquid separation membrane laminate for refrigerant. The gas-liquid separation membrane module for refrigerant of the present invention can be used to separate a gas-liquid two-phase flow, which is a gas-liquid coexisting refrigerant, into a gas refrigerant and a liquid refrigerant.

  The refrigerant gas-liquid separation membrane module of the present invention comprises a container whose internal space is separated into a first space and a second space by the refrigerant gas-liquid separation membrane or refrigerant gas-liquid separation membrane laminate of the present invention. The first space has a gas-liquid two-phase flow liquid inlet and a liquid phase outlet from the external space, and the second space has a gas phase outlet to the external space. It is also preferable to provide a cock or a valve for adjusting the flow rate or pressure at the gas-liquid two-phase flow liquid inlet, liquid phase outlet and / or gas phase outlet of the gas-liquid separation membrane module for refrigerant.

  The material of the container of the gas-liquid separation membrane module for refrigerant is, for example, a metal such as stainless steel, a fluorine-based resin (polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkoxy-trifluoroethylene copolymer, tetrafluoroethylene- Hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polytrifluoroethylene chloride, polyvinylidene fluoride, polyvinyl fluoride, Teflon (registered trademark) AF, Hyflon AD (registered trademark), Cytop ( Registered trademark)), acrylic resin, polycarbonate, polystyrene, polysulfone, polyethersulfone, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, cellulose, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyester, nylon, polyimide, poly De, polyphenylene sulfide, polyarylate, and can be exemplified organic substances typified by copolymers thereof.

  For example, in one mode in which the cross-sectional schematic diagram is shown in FIG. 5, the internal space of the refrigerant gas-liquid separation membrane module is divided into two by the refrigerant gas-liquid separation membrane laminate 11, and the gas-liquid is separated into the first space. A two-phase flow liquid inlet 13 and a liquid phase outlet 14 are provided, and a gas phase outlet 12 is provided in the second space. In FIG. 5, the gas-liquid separation membrane laminate for refrigerant is illustrated as a simple shape. However, in order to increase the gas-liquid separation area, a known structure such as a spiral type or a pleat type is used in such a module. May be.

  In the gas-liquid separation method of the gas-liquid mixed refrigerant of the present invention, the refrigerant in the gas-liquid coexistence state is introduced from the gas-liquid two-phase flow liquid inlet of the gas-liquid separation membrane module of the present invention under pressure, and the gas-liquid refrigerant The refrigerant is separated into gas and liquid through the pores of the separation membrane, the liquid phase of the refrigerant is taken out from the liquid phase outlet, and the gas phase of the refrigerant is taken out from the gas phase outlet.

  Examples of the refrigerant that can be suitably used include ammonia, carbon dioxide gas, isobutane, chlorofluorocarbon refrigerant (for example, R12 (dichlorofluoromethane) or R22 (chlorodifluoromethane)), and hydrofluorocarbon refrigerant (for example, R407C or R410A). It is done.

The refrigerant gas-liquid separation membrane module of the present invention is not limited, but may be applied to a refrigeration cycle as shown in FIG.
In FIG. 8, the refrigeration cycle 20 includes a compressor 21 that compresses the refrigerant, a condenser 22 that cools the refrigerant compressed by the compressor 21 and liquefies the refrigerant, and a decompression unit that decompresses the refrigerant liquefied by the condenser 22. An expansion valve 23, a refrigerant gas-liquid separation membrane module 24 that separates the refrigerant decompressed by the expansion valve 23 into a liquid phase and a gas phase, and a refrigerant gas-liquid separation membrane module 24. A storage tank 25 for storing the refrigerant (liquid phase), and an evaporator 26 for vaporizing the refrigerant (liquid phase).

  The outlet of the compressor 21 and the inlet of the condenser 22 are the first connection pipe 27, and the outlet of the condenser 22 and the inlet of the expansion valve 23 are the second connection pipe 28, and the outlet of the expansion valve 23 and the gas-liquid separation membrane module 24 are connected. A refrigerant introduction pipe 29 is provided between the gas-liquid separation membrane module 24 and the storage tank 25, and a refrigerant extraction pipe 30 is provided between the storage tank 25 and the inlet of the evaporator 26. The outlet side of the liquid separation membrane module 24 and the evaporator 26 is connected by a bypass pipe 32, and the outlet of the evaporator 26 and the inlet of the compressor 21 are connected by a third connection pipe 33.

  The gas-phase refrigerant exiting from the gas-liquid separation membrane module for refrigerant 24 is guided to the bypass pipe 32, bypasses the evaporator 26, and returns to the compressor 21.

  The liquid-phase refrigerant accumulated in the storage tank 25 is sent to the evaporator 26 through the refrigerant outlet pipe 31. Therefore, if the separation in the refrigerant gas-liquid separation membrane module 24 is complete, the vapor phase refrigerant is not supplied to the evaporator 26.

  If the liquid-phase refrigerant contained in the gas-liquid coexisting refrigerant bypasses the evaporator and enters the compressor in the form of mist or liquid droplets, the problem arises that the latent heat of the refrigerant is not effectively used for refrigeration. However, if the gas-liquid separation membrane module for refrigerant of the present invention is used, the gas-phase refrigerant can be efficiently and reliably separated from the gas-liquid coexisting refrigerant, and the latent heat of the refrigerant can be effectively used without waste.

  Next, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.

[Observation of mold and film structure]
Observation with a scanning electron microscope: A sample cut to an arbitrary size from the produced mold and the gas-liquid separation membrane for refrigerant is fixed to a sample stage with a conductive double-sided tape, and platinum is sputtered to a thickness of about 3 nm to make a microscope. A sample was used. Using a high-resolution scanning electron microscope apparatus (S-3000N, manufactured by Hitachi, Ltd.), the surface and cross section of the sample were observed at an acceleration voltage of 1.0 kV and a predetermined magnification. The average value was obtained by measuring 50 locations of the diameter of the convex portion of the mold, the thickness of the mold and membrane, the pore diameter, and the pore pitch.
Observation with an atomic force microscope: A gas-liquid separation membrane sample for a refrigerant cut out to an arbitrary size from the prepared sample was fixed to a sample table with a double-sided tape to obtain an observation sample. Using an atomic force microscope (NanoScope III manufactured by Digital Instruments), the surface shape of the film was observed at a predetermined magnification using a NCHV probe manufactured by Veeco.

[Thickness]
Porous film substrate: Measured using a film thickness meter (Digital Indicator IDF-130, manufactured by Mitutoyo). Measurements were made at 10 different points to obtain an average value.
Gas-liquid separation membrane for refrigerant: The film thickness was measured by cross-sectional observation of the gas-liquid separation membrane for refrigerant using a scanning electron microscope.

[Porosity]
By observing the membrane with a scanning electron microscope, the volume of the pores in the measurement range of the gas-liquid separation membrane for refrigerant was measured, and the porosity was calculated by the following equation (1). Here, the volume of the hole was calculated on the assumption that the diameter of the upper surface is A, the diameter of the bottom surface is B, and the height is a truncated cone shape equal to the thickness of the film.
Porosity (%) = (pore volume in measurement range) / volume of membrane in measurement range × 100 (1)

<Example 1>
Anodization was performed for 50 seconds on an aluminum plate having a purity of 99.99% at a formation voltage of 60 V using 0.3 M oxalic acid as the electrolyte. Thereafter, the film was immersed in 2% by weight phosphoric acid at 30 ° C. for 10 minutes to carry out pore size expansion treatment. This operation was repeated 5 times, and the first mold made of anodized porous alumina having tapered pores having a pore pitch of 300 nm, a pore diameter of 0.2 μm, and a pore depth of 0.3 μm, 200 mm in length and width. Got.

  Next, the first mold was electroformed. First, surface electrode treatment was performed by nickel sputtering, and nickel electroplating was performed thereon. A second mold made of nickel was obtained by peeling the metal plating from the mold.

  The obtained second mold was thoroughly washed in distilled water. A pre-prepared polysulfone (manufactured by Teijin Amoco, UDEL-P3500) in an N-methylpyrrolidone solution of 2 wt% was spin-coated on this second mold, dried at 80 ° C., and a thickness of 0.02 on the second mold. A 4 μm refrigerant gas-liquid separation membrane precursor was formed. The residual film on the surface of the gas-liquid separation membrane precursor for refrigerant was removed by plasma etching to a thickness of about 0.15 μm.

  Using a polypropylene non-woven fabric (Syntex (registered trademark) MB MO18YY manufactured by Mitsui Chemicals, Inc.) of 200 mm in length and width as the porous film substrate, the thin film on the second mold and 160 ° C. (The heat distortion temperature of polysulfone is about 175 ° C. (The melting point of polypropylene is about 160 ° C.), and the thin film is peeled off from the second mold and laminated with the porous film substrate at the same time, and the gas-liquid separation for the refrigerant made of polysulfone is formed on the polypropylene nonwoven fabric. A gas-liquid separation membrane laminate for a refrigerant in which membranes were laminated was obtained. The thickness of this laminated body was 157 μm.

  When this gas-liquid separation membrane for refrigerant was analyzed with an electron microscope and an atomic force microscope, the porosity was 40%, the pore diameter was 50, and the minimum value was 0.18 μm, the maximum value was 0.23 μm, and the average value was 0.00. The standard deviation was 21 μm and 0.02. The average film thickness was 0.25 μm.

Next, a flat membrane of the gas-liquid separation membrane laminate for refrigerant was cut into 5 cm × 20 cm to produce a flat membrane module as shown in FIG. 5 and used for a gas-liquid separation test. The effective membrane area was 76 cm ² .

  In FIG. 5, the gas-liquid two-phase fluid is introduced from the gas-liquid two-phase fluid inlet 13. The gas-liquid two-phase fluid is separated into a gas phase and a liquid phase by the gas-liquid separation membrane laminate 11, the gas phase passes through the gas-liquid separation membrane laminate 11 and exits from the gas phase outlet 12, and the liquid phase is the liquid phase It is discharged from the outlet 14.

  Using R407C (manufactured by Daikin Industries, Ltd.) as a refrigerant, a gas-liquid two-phase flow gas-liquid separation test was performed using a gas-liquid separation performance evaluation system as shown in FIG. This gas-liquid separation performance evaluation system includes a gas-liquid two-phase flow generation unit including a refrigerant storage tank 34, a liquid feed pump 35, and an expansion valve 23, a gas-liquid separation module 24, a liquid-phase storage tank 36, and a first safety valve 37. And a gas phase storage tank 38, a second safety valve 39, and a gas phase flow meter 40.

  In FIG. 9, the temperature of the entire evaluation system is adjusted to 38 ° C., R407C is supplied from the refrigerant storage tank 34 by applying pressure by the liquid supply pump 35, and the pressure is reduced to 1.56 MPa by the expansion valve 23. The phase flow was guided to the gas-liquid separation module 24. The liquid phase separated by the gas-liquid separation module 24 was led to the liquid phase storage tank 36, and the gas phase was led to the gas phase storage tank 38. The gas phase flow rate (throughput (l / min)) introduced to the gas phase storage tank 38 was measured, and the mixed state of mist and liquid droplets was examined visually. The results are shown in Table 1.

<Example 2>
A positive photoresist was applied at a thickness of 300 nm on a smooth and polished glass plate of 200 mm in both length and width to obtain a substrate with a photoresist. The light emitted from the TEM00 mode argon laser (wavelength 364 nm) is divided into two by a mirror, irradiated from two directions at an angle of 45 degrees to form an interference fringe, and the formed interference fringe is 120 degrees. The photoresist was exposed by irradiating the substrate with the photoresist from three directions at intervals. After the exposure, development was performed to remove the uncured portion, thereby obtaining a third mold.

  The projections of the third mold had a pitch of 260 nm, the diameter of the convex portion was 250 nm at the bottom, 120 nm at the top, and the height was 300 nm.

  Next, this third mold was electroformed. First, surface electrode treatment was performed by nickel sputtering. Then, electroplating of nickel was performed, and the metal plating was peeled off from the third mold, whereby the transferred first mold was obtained by inverting the uneven structure of the third mold.

  Next, as a treatment for peeling off the second electroforming, the surface of the first mold was oxidized to form a metal oxide film. Then, nickel plating was applied to the surface of the first mold as electroforming. The metal mold was peeled from the first mold to obtain a second mold. Since the second mold is produced using the first mold as a master, it can be replenished even if it is broken.

  2 wt% of a pre-prepared polysulfone (manufactured by Teijin Amoco, UDEL-P3500) with 2 wt% N-methylpyrrolidone solution is spin-coated on this second mold, dried at 80 ° C., and 0.4 μm thick gas-liquid for refrigerant A separation membrane precursor was obtained on a second template.

  Next, the fix film HG-1 (manufactured by Fuji Copian Co., Ltd.) cut out to 200 mm in both length and width was laminated and peeled to release the gas-liquid separation membrane precursor for refrigerant from the mold.

  Polypropylene nonwoven fabric (Syntex (registered trademark) MB MO18YY manufactured by Mitsui Chemicals, Inc.) as a porous film substrate was cut into 200 mm both vertically and horizontally and overlapped with the refrigerant gas-liquid separation membrane precursor released from the mold. After heating at 160 ° C. to heat-fuse the gas-liquid separation membrane precursor for refrigerant and the porous film substrate, the fix film HG-1 was peeled off. The residual film on the surface of the refrigerant gas-liquid separation membrane precursor was removed by plasma etching to a thickness of about 0.15 μm to obtain a gas-liquid separation membrane laminate for refrigerant. The thickness of this laminated body was 158 μm.

  The gas-liquid separation membrane for refrigerant was analyzed with an electron microscope and an atomic force microscope. As a result, the porosity was 48%, and the pore diameter was measured to be 50. The minimum value was 0.17 μm, the maximum value was 0.24 μm, and the average value was 0.8. The standard deviation was 22 μm and the standard deviation was 0.02. The average film thickness was 0.26 μm.

Next, the flat membrane of the gas-liquid separation membrane laminate for refrigerant was cut into 5 cm × 20 cm, and a flat membrane module as shown in FIG. 5 was produced. The effective membrane area was 76 cm ² . This flat membrane module was subjected to a gas-liquid separation test in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
100 parts by weight of polytetrafluoroethylene particles and 22 parts by weight of petroleum naphtha are mixed and extruded by an extruder equipped with a T-die to form a flat film. After heating and drying, the flat film is uniaxially stretched to 120% at 250 ° C. Produced. This flat film was baked at 360 ° C. for 15 minutes. When the obtained flat film was analyzed with an electron microscope and an atomic force microscope, the porosity was 40%, and the pore diameter was measured to be 50. The minimum value was 0.02 μm, the maximum value was 0.24 μm, the average value was 0.14 μm, The standard deviation was 0.09. The average film thickness was 90 μm.

Next, this flat membrane was cut out to 5 cm × 20 cm, a flat membrane module as shown in FIG. 6 was produced, and a gas-liquid separation test was performed. The effective membrane area was 76 cm ² .

  In FIG. 6, the gas-liquid two-phase fluid is introduced from the gas-liquid two-phase fluid inlet 17. The gas-liquid two-phase fluid is separated into a gas phase and a liquid phase by the flat film 15, the gas phase passes through the flat film 15, exits from the gas phase outlet 16, and the liquid phase is discharged from the liquid phase outlet 18. This flat membrane module was subjected to a gas-liquid separation test in the same manner as in Example 1. The results are shown in Table 1.

<Comparative example 2>
A mesh filter (NY50-HD, manufactured by SEFAR, 269 mesh, opening 50 μm, thickness 102 μm) was cut into 5 cm × 20 cm, and a flat membrane module as shown in FIG. 6 was produced. The effective membrane area was 76 cm ² . This flat membrane module was subjected to a gas-liquid separation test in the same manner as in Example 1. The results are shown in Table 1.

  As is clear from Table 1, the efficiency of the gas-liquid separation treatment was low in a membrane having a large pore size distribution and a small average pore size. In addition, a coarse mesh filter has a large throughput, but gas-liquid separation is insufficient, and mist and droplets cannot be separated. In contrast, the gas-liquid separation membrane for refrigerant of the present application was capable of gas-liquid separation treatment with high efficiency.

  The gas-liquid separation membrane for refrigerant of the present invention can be suitably used in the field of gas-liquid separation treatment of a refrigeration cycle.

DESCRIPTION OF SYMBOLS 1 2nd casting_mold | template by a 1st manufacturing method 2 Aluminum 3 Anodized porous alumina 4 Pore 5 Separation membrane 6 Porous film base material 7 Substrate 8 Convex part which consists of a taper-shaped protrusion 8a Top part of convex part 8b Convex part Bottom part 9 Third mold 10 by the second manufacturing method 10 First mold 11 by the second manufacturing method 11 Gas-liquid separation membrane laminate for refrigerant of the module used in Examples 1 and 2 12 In Examples 1 and 2 Gas phase outlet of the module used 13 Gas-liquid two-phase flow inlet of the module used in Examples 1 and 2 14 Liquid phase outlet of the module used in Examples 1 and 2 15 of the module used in Comparative Examples 1 and 2 Flat membrane and mesh filter 16 Gas phase outlet of module used in Comparative Examples 1 and 2 17 Gas-liquid two-phase flow inlet of module used in Comparative Examples 1 and 2 18 Comparative Example 1 Liquid phase outlet of module used in 2 and 19 Gas-liquid separation membrane module for refrigerant 20 Refrigeration cycle 21 Compressor 22 Capacitor 23 Expansion valve 24 Gas-liquid separation membrane module for refrigerant 25 Storage tank 26 Evaporator 27 First connection pipe 28 Second connection Pipe 29 Refrigerant introduction pipe 30 Refrigerant outlet pipe 31 Refrigerant outlet pipe 32 Bypass pipe 33 Third connection pipe 34 Refrigerant storage tank 35 Liquid feed pump 36 Liquid phase storage tank 37 First safety valve 38 Gas phase storage tank 39 Second Safety valve 40 Gas phase flow meter

Claims (9)

  A gas-liquid separation membrane for refrigerant having pores, wherein the pore pitch is 30 to 1000 nm, the pore diameter is 10 to 300 nm, and the thickness of the gas-liquid separation membrane is A refrigerant gas-liquid separation membrane having a standard deviation in the pore size distribution of 30 to 1000 nm and 30% or less of the average value. 2. The method according to claim 1, comprising the steps of: transferring the irregularities of the first mold having recesses made of pores to a second mold; and transferring the irregularities of the second template to a film made of a polymer. A method for producing a gas-liquid separation membrane for refrigerant.   The manufacturing method of Claim 2 with which the 1st casting_mold | template which has the recessed part which consists of the said pore is produced by anodizing an aluminum plate. A step of transferring the irregularities of the third mold having projections made of protrusions to the first mold;
2. The gas-liquid separation membrane for refrigerant according to claim 1, comprising a step of transferring the irregularities of the first template to a second template, and a step of transferring the irregularities of the second template to a membrane made of a polymer. Manufacturing method.   5. The manufacturing method according to claim 4, wherein the third mold having the convex portion formed of the protrusion is produced by developing the photoresist layer laminated on the substrate by interference exposure.   A gas-liquid separation membrane laminate for cold multiplication, wherein the gas-liquid separation membrane for refrigerant according to claim 1 and a porous film substrate are laminated. The step of laminating the gas contact film for refrigerant according to claim 1 and the porous film substrate, and melting the gas contact film for refrigerant and / or the porous film substrate by heating to fuse them together The manufacturing method of the gas contact film | membrane laminated body for refrigerant | coolants including the process to make.   An internal space is composed of a container that is separated into a first space and a second space by the gas-liquid separation membrane for refrigerant according to claim 1 or the gas-liquid separation membrane laminate for refrigerant according to claim 6. A gas-liquid separation membrane module for refrigerant having a gas-liquid two-phase flow liquid inlet and a liquid-phase outlet from the external space in the space and a gas-phase outlet to the external space in the second space.   A refrigerant in a gas-liquid coexistence state is introduced from the gas-liquid two-phase flow liquid inlet of the gas-liquid separation membrane module for refrigerant according to claim 8, a liquid-phase refrigerant is taken out from the liquid phase outlet, and the gas phase outlet A gas-liquid separation method for a refrigerant, comprising a step of separating a gas-liquid coexisting refrigerant into a liquid phase and a gas phase by taking out the gas-phase refrigerant from the liquid phase.

Images