JP2017213556A - Water purification system for oil-mixed water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for producing purified water in which an oil component is inexpensively and efficiently separated and removed from oil-mixed water in which the oil component is mixed to obtain filtrate, then, the oil component and salt which are dissolved in the obtained filtrate can be removed with high precision, preferably, the removed oil component can be recovered and reused, and dissolved matters are removed.SOLUTION: A water purification device includes: a filtration part for filtering liquid to be treated by an oil-water separation filter having at least nonwoven fabric having 25.4 mN/cm or less of wet tension; and a distillation part for distilling filtrate obtained by the filtration part.SELECTED DRAWING: None

Description

  The present invention relates to an oil-mixed water purification system.

In the drilling of oil, coal, gas, etc., accompanying water, which is a mixture of an aqueous salt solution and oil, is produced along with the main product.
In conventional oil fields and gas fields, the oil and gas field ages as the mining progresses, and therefore, the following mining mode is generally employed with the aging.
First, at the beginning of mining, only oil or gas is self-injected due to underground pressure. Next, along with the aging of the oil and gas field, the groundwater and the like will be produced along with the oil and gas. When the oil and gas cannot be self-injected due to aging, water or seawater is injected into the oil and gas field to increase the underground pressure and eject the oil and gas. In this final stage, accompanying water is produced more than when the oil and gas field is aged.
In recent shale oil and gas fields, when producing oil and gas, flacking water for hydraulic destruction of the ground is injected. Therefore, at the time of production of oil gas, this injected water is produced at the same time as accompanying water.

Since these accompanying waters contain a large amount of oil, salt, etc., during the production of oil gas, when these accompanying waters are reused or discarded, for example, they can be efficiently and accurately converted into water and oil phases. There is a need to separate and remove salt from the aqueous phase.
The accompanying water is first divided into an oil phase and an aqueous phase by gravity separation. The oil phase is recovered and incorporated into the refining process. However, since the aqueous phase further contains a small amount of oil along with a substantial amount of salt, further purification is required for reuse or disposal. In particular, in the case of offshore oil field platforms and drilling vessels, strict environmental standards are imposed when the unnecessary water phase is dumped in the sea. In addition, when purified water is used as drinking water or domestic water, an extremely high level of purification is required.

  In order to purify the aqueous phase after gravity separation, firstly, an oil separation step of removing oil contained in the aqueous phase, and further removing dissolved substances (for example, inorganic salts) from the aqueous phase from which the oil has been removed. A two-stage method comprising a lysate separation step is employed.

In the oil separation step, a method of capturing oil with a polymer flocculant is employed, and usually further purification using a coalescer is used. The oil captured by the polymer flocculant is discarded together with the polymer flocculant. According to this method, the recovered oil cannot be used, the polymer flocculant cost and the disposal cost are generated, and the degree of purification is insufficient and the purified water contains a significant amount of oil. There is a problem.
In the lysate separation step, a method such as a reverse osmosis membrane method is employed. These methods are extremely effective methods for removing salts dissolved in water.
However, in the reverse osmosis membrane method, when the salt concentration of the water to be treated becomes high, the mechanical pressure required for the purification treatment increases and purification becomes difficult. When the purified water is obtained from the water to be treated, the untreated water is concentrated as the purification proceeds, so that the recovery rate of purified water by the reverse osmosis membrane method is limited.

In order to increase the recovery rate of purified water, a distillation method having a high concentration limit, a membrane distillation method, etc. are more effective in the lysate separation step. In these methods, the treatment speed in the lysate separation step is not easily affected by the salt concentration.
On the other hand, in the distillation method or the membrane distillation method, if water containing oil is supplied as water to be treated, problems may occur. Particularly in the membrane distillation method, when water containing oil is supplied, the oil adheres to the hydrophobic porous membrane used in the membrane distillation method, causing water to leak to the purified water side through the pores. Become. There may be a problem that the durability of the membrane is impaired or the purification performance is impaired.
In order not to cause the above problem, it is effective to remove the oil mixed in a small amount in the water after the oil separation step and to use it in the dissolved matter separation step.

Therefore, usually, a pretreatment for removing the residual oil is performed after the oil-water separation and before the dissolved matter separation. This pretreatment is often performed in the following multi-stage for the purpose of avoiding clogging of the filter.
The treated water after oil-water separation is first treated with a coalescer or the like to remove most of the residual oil, and then preferably hollow fiber MF (microfilter) and preferably hollow fiber UF (ultra filter). Processing that is used in this order is performed.

If such a multi-stage pretreatment can be performed in one stage, it is very useful in terms of process and cost. Moreover, it is difficult to recover and reuse the oil removed by these treatments.
Thus, there is a demand for means that can remove the residual oil from the aqueous phase after gravity separation of the accompanying water at low cost and efficiently, and hopefully recover and reuse the removed oil. In particular, since the available energy resources are limited on the marine platform and the ship, it is preferable not to use energy other than natural power for operation, or at least to save labor as much as possible.

  If there is a water purification method that combines the oil-water separation method and the dissolved matter separation method as described above, it will be possible to collect valuable materials, produce fresh water, and reduce the volume of waste water from oil-mixed water such as associated water at once. Therefore, it is extremely useful.

JP 2014-184398 A JP 2013-185127 A International Publication No. 2016/006670 JP 2014-128764 A

  The present invention has been made in consideration of the above circumstances. Accordingly, an object of the present invention is to obtain a filtrate by separating and removing the oil from the oil mixed water mixed with the oil at low cost and efficiently, and also to obtain the oil and salt dissolved in the obtained filtrate with high accuracy. It is an object of the present invention to provide a means for producing purified water which can be removed, preferably the removed oil can be recovered and reused, and the dissolved matter is removed.

The present inventors diligently studied to solve the above problems. As a result, the inventors have found that the above-described object can be achieved by the technology summarized below.
The present invention is as follows.

(1) At least
A filtration unit for filtering the liquid to be treated with an oil-water separation filter having a nonwoven fabric with a wetting tension of 25.4 mN / cm or less;
A distillation section for distilling the filtrate obtained in the filtration section;
The water purifier characterized by having.
(2) The water purifier according to (1), wherein the nonwoven fabric is a nonwoven fabric subjected to a hydrophilic treatment.

(3) The hydrophilic treatment
Sulfonation treatment and one or more treatments selected from the group consisting of grafting treatment with one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, polymethylpyrrolidinone, polyalkylene glycol, and polyether The water purifier according to (2).
(4) The water purifier according to any one of (1) to (3), wherein a hexadecane contact angle after water impregnation of the nonwoven fabric is 5 ° or more.

(5) Of the nonwoven fabric,
The basis weight is 1 to 500 g / m ² .
The fiber thickness is 0.1-50 μm,
The pore size is 0.1-120 μm and the thickness is 0.1-5 μm,
The water purifier according to any one of (1) to (4).
(6) The filtration unit is
The liquid to be treated and the filtrate are adjacent via the oil / water separation filter,
The water purifier according to any one of (1) to (5), having a function of filtering the liquid to be treated while maintaining the liquid surface of the liquid to be treated higher than the liquid level of the filtrate.

(7) The water purifier according to any one of (1) to (6), wherein the distillation unit is a membrane distillation system.
(8) The membrane distillation system is
A filtrate evaporating part in which the liquid phase part 1 where the filtrate is present and the gas phase part 1 are adjacent to each other via a hydrophobic porous membrane;
A liquid phase part 2 through which cooling water flows, a gas phase part 2 adjacent to each other via a cooling body, and a gas phase part 3 connecting the gas phase part 1 and the gas phase part 2 are connected.
A membrane distillation system comprising:
The water purifier according to (7), wherein the gas phase parts 1 to 3 have a pressure equal to or higher than 1 kPa and a saturated vapor pressure of water at a filtrate temperature.
(9) The water purifier according to (8), wherein the gas phase part 1 and the hydrophobic porous membrane are immersed in the liquid phase part 1.

(10) The water purifier according to (8) or (9), wherein a shortest distance between the hydrophobic porous membrane and the cooling body is 10 mm or more.
(11) The water purifier according to any one of (8) to (10), wherein the filtrate temperature is 50 ° C or higher.

(12) The hydrophobic porous membrane contains at least one resin selected from the group consisting of polysulfone, polyethersulfone, polyethylene, polypropylene, polyvinylidene fluoride, and polytetrafluoroethylene, (8) to (11) ) The water purifier according to any one of the above.
(13) The water purifier according to any one of (8) to (12), wherein the hydrophobic porous membrane is a hollow fiber membrane.

(14) The hydrophobic porous membrane has a surface porosity of 20% or more on the membrane surface in contact with the filtrate, and an air permeability coefficient of 7.0 × 10 ⁻⁷ m ³ / m ² · sec · The water purifier according to any one of (8) to (13), which is Pa or higher.
(15) The water purifier according to any one of (8) to (14), wherein the hydrophobic porous membrane has an average pore diameter of 0.15 μm or more and a porosity of 60% or more.

According to the present invention, oil and salt can be efficiently and efficiently removed from oil-mixed water containing oil and salt. According to a preferred aspect of the present invention, a means for recovering and reusing the removed oil, and producing purified water from which the oil has been removed, preferably over a long period of time, is provided.
According to the present invention, the operational life of the membrane distillation system can be extended compared to the case where the oil-mixed water is directly purified by the membrane distillation system.

It is a schematic diagram which shows the system of a membrane distillation method. 1A shows the DCMD method, FIG. 1B shows the AGMD method, FIG. 1C shows the VMD method, and FIG. 1D shows the SGMD method. It is a mimetic diagram for explaining one form of a membrane distillation system in the present invention. It is a schematic diagram for demonstrating another form of the membrane distillation system in this invention. It is a schematic diagram for demonstrating another one form of the membrane distillation system in this invention. It is a schematic diagram for demonstrating another one form of the membrane distillation system in this invention. It is a schematic diagram for demonstrating another one form of the membrane distillation system in this invention. It is a schematic sectional drawing for demonstrating the one aspect | mode of the filtration part in this invention. It is a graph which shows the time-dependent change of the electrical conductivity of purified water at the time of performing membrane distillation in Example 1 and Comparative Example 1.

  Hereinafter, a mode for carrying out the present invention (hereinafter also referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

  The water purification system of this embodiment has at least a filtration unit that filters the liquid to be treated with an oil-water separation filter and a distillation unit that distills the filtrate obtained by the filtration unit. In addition to these, for example, a solid phase separation means for separating sand, rocks, etc .; a magnetic means for separating magnetic substances;

<< Processed liquid >>
The liquid to be treated applied to the system of the present embodiment is oil mixed water containing oil. In order to maximize the effects of the present invention, an oil / water mixture containing an oil and a salt is desirable. Specific examples of the oil-mixed water include industrial wastewater containing oil, accompanying water discharged during production of oil and natural gas, and the like.
The concept of oil in this specification is represented by, for example, shale oil, oil sand, synthetic oil, derived synthetic oil, coal liquefaction, etc., in addition to conventional oil such as oil extracted from conventional oil fields. Unconventional oil is also included. The concept of natural gas in this specification includes, for example, shale gas, coal bed methane (also known as coal seam gas), tight sand gas, methane hydride, in addition to conventional gas such as gas obtained from conventional gas fields. Non-conventional gases represented by rates and the like are also included.

The content of oil in the liquid to be treated applied to the system of the present embodiment may exceed the saturation dissolution amount, and may have a high concentration enough to separate into two layers of oil and water by standing. The salt concentration in the liquid to be treated may be not more than a saturated dissolution amount and may be completely dissolved, or may be in a state where a part of the salt is precipitated exceeding the saturation dissolution amount.
Thus, the system of the present embodiment has an advantage that it can be suitably applied to purification of oil-mixed water containing at least one of oil and salt in an extremely high concentration.

<< Filtering section >>
The filtration part in the water purifier of this embodiment has a function which filters a to-be-processed liquid with an oil-water separation filter.

<Oil-water separation filter>
The oil / water separation filter is made of a nonwoven fabric having a wetting tension of 25.4 mN / m or less. The nonwoven fabric preferably has a hexadecane contact angle of 5 ° or more after being impregnated with water.

Examples of the material for the nonwoven fabric include aramid, cellulose, glass, nylon, vinylon, polyester, polyolefin, rayon, polyamide, polyalkylene terephthalate, polyalkylene naphthalate, and the like. Among these, a nonwoven fabric made of a material selected from polyamide, polyester, and polyolefin is preferable from the viewpoint that the degree of hydrophilicity (and oil repellency) can be arbitrarily controlled by the hydrophilic treatment preferably performed in the present embodiment. More preferably, the nonwoven fabric is made of one or more materials selected from the group consisting of nylon, polyethylene terephthalate, polyethylene, polypropylene, and EVA (ethylene / vinyl acetate copolymer). Particularly preferred materials are nylon, polypropylene or polyethylene terephthalate.
The non-woven fabric is preferably a hydrophilized non-woven fabric. The hydrophilic nonwoven fabric can be produced by hydrophilizing the substrate (A).

[Substrate (A)]
The decorative fabric used as the substrate (A) is preferably a decorative fabric made of nylon 6, nylon 66, PET, or PBT from the viewpoint of easy hydrophilization treatment and the hydrophilicity of the substrate itself.
The nonwoven fabric used as the substrate (A) preferably has a dense average pore diameter and low flow resistance. For this reason, the nonwoven fabric preferably has a small average pore diameter while having a high porosity.

If the porosity of the substrate (A) is less than 50%, the flow resistance becomes large, the film tends to be clogged, and the life is shortened. On the other hand, if the porosity is greater than 90%, there are problems in terms of strength and shape retention, and the variation in average pore diameter increases, which is not preferable. A particularly preferred range of the porosity of the substrate (A) is 60 to 85%. A preferable average pore diameter of the substrate (A) is 50 μm or less.
Preferably, an undecorated cloth having an average fiber diameter of 0.1 to 10 μm, a basis weight of 10 to 500 g / m ² , and a porosity of 60 to 90% is used, and the thickness, air permeability, and the like are appropriately adjusted to A substrate (A) having an average pore diameter and flow resistance can be obtained. Examples of the method for densifying (decreasing) the average pore diameter of the nonwoven fabric include, for example, “increasing the basis weight”, “decreasing the void”, or “decreasing the diameter of the configured fiber”, or these The method etc. which combine two or more of them are mentioned.

  The manufacturing method of a nonwoven fabric is not specifically limited. However, using short fibers having a fiber diameter of 10 μm or less, for example, after forming into a web by a papermaking method, an air raid method, a card method, etc., water entanglement by a columnar flow method (spun lace method), entanglement by a hot gas, heat and A nonwoven fabric can be manufactured by the roll press-bonding method etc. by a pressure. The short fibers having a fiber diameter of 10 μm or less can be produced by, for example, melt-blowing, spunbond splitting, electrospinning, force spinning, or the like, or commercially available products.

The nonwoven fabric used as the substrate (A) is preferably produced by a melt blow method. Nonwoven fabric produced by the melt blow method is, for example:
(1) The fiber diameter is thin,
(2) The maximum average pore size between fibers is small,
(3) There is little variation in the average pore diameter of the nonwoven fabric,
(4) The fiber surface area is large,
(5) It has advantages such as softness and softness (drapability), and can be suitably used as the substrate (A). The decorative cloth can exhibit stable filtration performance due to the characteristics (1) to (3) described above, and can provide a large processing area by specifying (4).

  In the melt-blowing method, the molten resin discharged from the nozzle is refined by being pulled by spinning gas or gravity, and the yarn group accumulated on the collector net is roll-bonded by a suction fan provided in the collector. A nonwoven fabric can be formed.

  The substrate (A) may be composed of a single layer nonwoven fabric or a multilayer nonwoven fabric. When the substrate (A) is composed of a multilayer nonwoven fabric, the substrate (A) is composed of a reinforcing layer for exerting the strength of the substrate (A) and a separation layer for exhibiting a high water permeability, and each layer shares functions. May be. The reinforcing layer can be, for example, a layer made of a resin having a low basis weight and high strength. The thickness of the separation layer is preferably 0.1 to 5 mm. By using a nonwoven fabric having a thickness of 0.1 mm or more as the separation layer, efficient oil-water separation is ensured. On the other hand, by setting the thickness of the separation layer to 5 mm or less, the amount of water per unit time can be increased, and the process time for oil-water separation is shortened. The thickness of the nonwoven fabric which comprises a separated layer becomes like this. Preferably it is 0.2-3 mm, More preferably, it is 0.5-2 mm. A case where two or more non-woven fabrics thinner than the above range are used as the separating layer to have a thickness within the above range is also included in the preferred embodiment of the present invention.

The basis weight of the nonwoven fabric used as the substrate (A) is preferably ¹ to 500 g / m ² . The “weight per unit area” in the present specification refers to the mass per unit area of the nonwoven fabric. When the basis weight is within the above range, both the oil / water separation efficiency and the water permeation amount are increased, which is preferable. Basis weight, more preferably from 10 to 250 g / ^{m 2,} further preferably 50 to 150 g / ^{m 2.} In the case where two or more nonwoven fabrics are used in an overlapping manner, this basis weight means the total weight of each layer.

  The nonwoven fabric used as the substrate (A) preferably has a fiber thickness of 0.1 to 10 μm. When the thickness of the fibers constituting the nonwoven fabric is 0.1 μm or more, it is possible to ensure that the fiber surface of the nonwoven fabric preferably subjected to hydrophilic treatment has a significantly high area in contact with the supplied oil-mixed water. it can. On the other hand, by setting the fiber thickness of the nonwoven fabric to 10 μm or less, a desired water permeability can be obtained even if the average pore diameter is reduced. Therefore, by using a non-woven fabric made of fibers having a thickness in the above range as the substrate (A) in the oil / water separation filter, a suitable oil / water separation ability can be exhibited. The fiber thickness of the nonwoven fabric is more preferably 0.1 to 7 μm, and further preferably 0.2 to 5 μm.

  The nonwoven fabric used as the substrate (A) preferably has an average pore size of 0.1 to 20 μm. When the average pore diameter in the nonwoven fabric is 0.1 μm or more, a substantial water permeability can be ensured. On the other hand, by using a non-woven fabric having an average pore diameter of 20 μm or less as the substrate (A), the performance that does not allow oil in the form of an emulsion to pass through is reliably imparted. The average pore diameter of the nonwoven fabric is more preferably 0.2 to 17 μm, and further preferably 0.2 to 15 μm.

For the reasons described above, as the substrate (A),
The basis weight is 1 to 500 g / m ² .
It is extremely preferable to use a nonwoven fabric having a fiber thickness of 0.1 to 10 μm and an average pore diameter of 0.1 to 20 μm.

[Hydrophilic treatment]
In a preferred aspect of the present embodiment, the substrate (A) as described above can be used as an oil-water separation filter by hydrophilizing it. By subjecting the substrate (A) to a hydrophilic treatment, appropriate hydrophilicity and oil repellency can be imparted to the nonwoven fabric of the material.
That is, when oil-mixed water is supplied onto a nonwoven fabric that has been hydrophilized, the water can permeate and pass through the nonwoven fabric, but the oil is preferably retained as oil droplets on the nonwoven fabric. The With such a mechanism, efficient oil-water separation can be performed.

  As the hydrophilic treatment method in the present embodiment, both chemical treatment and physical treatment can be performed.

Examples of chemical treatment include sulfonation treatment, grafting treatment, and coating treatment; examples of physical treatment include surface roughening treatment, plasma treatment, corona treatment, ultraviolet treatment, flame treatment, and the like. , Can be mentioned respectively. Of these, chemical treatment is preferred because the degree of hydrophilization can be easily controlled within a desired range.
The chemical hydrophilization treatment of the substrate (A) can be performed by a known method. For example, the sulfonation treatment can be performed by a method of immersing the substrate (A) in sulfuric acid or an aqueous solution thereof. The grafting treatment is performed on the main chain of the polymer constituting the nonwoven fabric of the substrate (A), for example, one selected from the group consisting of acrylic acid, methacrylic acid, polymethylpyrrolidinone, polyalkylene glycol, and polyether. This can be carried out by graft polymerization of the above monomers (or macromonomers). In this graft polymerization, for example, the substrate (A) is immersed in a grafting solution containing a desired monomer or monomer mixture and a suitable polymerization initiator, and if necessary, heated, irradiated (for example, ultraviolet rays) , Microwave, electron beam, etc.). From the viewpoint of environmental problems, the coating is preferably performed by a method of applying a non-fluorinated hydrophilic composition on the substrate (A) from the viewpoint that functions can be easily provided.

[Non-fluorine-based hydrophilic composition]
Hereinafter, a method for applying a non-fluorinated hydrophilic composition will be described as a preferred hydrophilic treatment method in the present embodiment.
The non-fluorinated hydrophilic composition in the present embodiment is
A non-fluorinated hydrophilic material (B);
A hydrolyzable silicon compound (C);
A dispersion medium;
It is preferable from the viewpoint of durability of the obtained oil / water separation filter. Preferably, it further contains a metal oxide (D). (D) The metal oxide of a component is the concept containing a silicon oxide.

(Non-fluorinated hydrophilic material (B))
The non-fluorinated hydrophilic material (B) in the present embodiment is preferably particles made of a non-fluorinated polymer.
The particularly preferred non-fluorinated hydrophilic material (B) in the present embodiment contains a hydrolyzable silicon compound or a hydrolysis condensate thereof (b1 component) and a polymer containing a hydrophilic functional group (b2 component). . At least a part of the b1 component may be present in a form incorporated as a copolymerization component in the b2 component. Such a material can be obtained by synthesizing the b2 component in the presence of the b1 component.

b1 Component: Hydrolyzable Silicon Compound As the b1 component in the present embodiment, a hydrolyzable silicon compound (h1) represented by the following formula (i) and a hydrolyzable silicon compound represented by the following formula (ii) ( h2), one or more selected from the group consisting of hydrolyzable silicon compounds (h3) represented by the following formula (iii) and other hydrolyzable silicon compounds (h4), and hydrolyzed condensates thereof Can be selected.

R ¹ _n SiX _4-n (i)
In the formula (i), R ¹ represents any one selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, and an aryl group, provided that the alkyl group, alkenyl group, alkynyl group, And the aryl group may each have a halogen group, a hydroxy group, a mercapto group, an amino group, a (meth) acryloyl group, or an epoxy group;
X represents a hydrolyzable group; and n is an integer of 0-3.
X ₃ Si—R ² _n —SiX ₃ (ii)
In formula (ii), X represents a hydrolyzable group;
R ² represents an alkylene group having 1 to 6 carbon atoms or a phenylene group; and n is 0 or 1.
R ³ — (O—Si (OR ³ ) ₂ ) _n —OR ³ (iii)
In the formula (iii), R ³ represents an alkyl group having 1 to 6 carbon atoms; and n is an integer of 2 to 8.

  The hydrolyzable group in the formulas (i) and (ii) is not particularly limited as long as it is a group that generates a hydroxyl group by hydrolysis. For example, a halogen atom, an alkoxy group, an acyloxy group, an amino group, a phenoxy group, An oxime group etc. are mentioned.

  Examples of the hydrolyzable silicon compound (h1) include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, tetra (n-butoxy) silane, and tetra (i-butoxy). ) Silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, Propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyl Ethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxy Silane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3- Methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trif Oloacetoxy) silane, triacetoxysilane, tris (trichloroacetoxy) silane, tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, tetrachlorosilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, Tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorosilane, tetrakis (methylethylketoxime) silane, tris (methylethylketoxime) silane, methyltris (methylethylketoxime) silane, phenyltris (methylethylketoxime) silane Bis (methylethylketoxime) silane, methylbis (methylethylketoxime) silane, bis (dimethylamino) C) Dimethylsilane, bis (diethylamino) dimethylsilane, bis (dimethylamino) methylsilane, bis (diethylamino) methylsilane, and the like.

  Examples of the hydrolyzable silicon compound (h2) include bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, bis (triphenoxysilyl) methane, bis (trimethoxysilyl) ethane, and bis (triethoxysilyl). ) Ethane, bis (triphenoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis (triethoxysilyl) propane, 1,3-bis (triphenoxysilyl) propane, 1,4 -Bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene and the like.

  Examples of the hydrolyzable silicon compound (h3) include tetramethoxysilane partially hydrolyzed condensate (for example, trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd., trade name “MSI 51” manufactured by Colcoat Co., Ltd.) "MS51" and "MS56" manufactured by Kagaku Co., Ltd., partially hydrolyzed condensates of tetraethoxysilane (trade names "Silicate 35" and "Silicate 45" manufactured by Tama Chemical Industry Co., Ltd.) ESI40 "," ESI48 "), co-hydrolyzed condensate of tetramethoxysilane and tetraethoxysilane (trade name" FR-3 "manufactured by Tama Chemical Industry Co., Ltd., trade name" EMSi48 "manufactured by Colcoat) Is mentioned.

  Examples of the hydrolyzable silicon compound (h4) include hexamethyldisilazane and hexamethylcyclotrisilazane.

  As for said hydrolysable silicon compound, only 1 type may be used independently and 2 or more types may be used together. These hydrolyzable silicon compounds are preferably taken into the non-fluorinated hydrophilic material (B) in a hydrolyzed and condensed state.

b2 component: polymer containing hydrophilic functional group The b2 component in the present embodiment is preferably a polymer or copolymer of a vinyl monomer.
This b2 component is an emulsion particle containing no fluorine atom, obtained by polymerizing a vinyl monomer component having an unsaturated bond with a radical, cation, or anion active species. The emulsion particles are composed of a polymer containing at least a hydrophilic functional group. Examples thereof include acrylic emulsion particles, styrene emulsion particles, acrylic styrene emulsion particles, acrylic silicon emulsion particles, silicon emulsion particles, and urethane resin emulsion particles.
By synthesizing this b2 component in the presence of the b1 component, the non-fluorinated hydrophilic material (B) in the present embodiment can be obtained.

As a vinyl monomer component for synthesizing the b2 component, for example,
Vinyl monomers having a hydroxyl group,
A vinyl monomer having a carboxyl group,
Vinyl monomers having amino groups,
Vinyl monomers having an ether group,
Vinyl monomers having an amide group,
Vinyl monomers having an epoxy group,
Examples thereof include a vinyl monomer having a sulfonic acid group and a vinyl monomer having none of the above functional groups. By using the b2 component synthesized from such a monomer, the hydrophilicity of the obtained non-fluorinated hydrophilic material (B) can be further increased.

Examples of the vinyl monomer having a hydroxyl group include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate;
Hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether;
Hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether;
Monoesters of polyoxyalkylene glycols obtained from various polyether polyols typified by polyethylene glycol and various unsaturated carboxylic acids typified by (meth) acrylic acid;
Adducts of various hydroxyl group-containing monomers described above with various lactones represented by ε-caprolactone;
Adducts of various epoxy group-containing unsaturated monomers represented by glycidyl (meth) acrylate and various acids represented by acetic acid;
Adducts of various unsaturated carboxylic acids typified by (meth) acrylic acid and various monoepoxy compounds other than epoxides of α-olefins typified by “Cardura E” (trade name, manufactured by Shell, The Netherlands) ;
Etc.

Examples of the vinyl monomer having a carboxyl group include unsaturated carboxylic acids such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid, and fumaric acid;
Of unsaturated dicarboxylic acids and saturated monohydric alcohols such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, mono-n-butyl fumarate Monoester (half ester);
Monovinyl esters of saturated dicarboxylic acids such as monovinyl adipate and monovinyl succinate;
Addition reaction product of various saturated polycarboxylic acid anhydrides such as succinic anhydride, glutaric anhydride, phthalic anhydride, trimellitic anhydride and the above-mentioned various hydroxyl group-containing vinyl monomers;
Monomers obtained by addition reaction of the above-mentioned various carboxyl group-containing monomers and lactones;
Etc.

Examples of the vinyl monomer having an amino group include 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-di-n-propylaminoethyl (meth) acrylate, and 3-dimethylamino. Tertiary amino group-containing (meth) acrylic acid esters such as propyl (meth) acrylate, 4-dimethylaminobutyl (meth) acrylate, N- [2- (meth) acryloyloxy] ethylmorpholine;
Tertiary amino group-containing aromatic vinyl monomers such as vinylpyridine, N-vinylcarbazole, N-vinylquinoline;
N- (2-dimethylamino) ethyl (meth) acrylamide, N- (2-diethylamino) ethyl (meth) acrylamide, N- (2-di-n-propylamino) ethyl (meth) acrylamide, N- (3- Tertiary amino group-containing (meth) acrylamides such as dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide, N- [2- (meth) acrylamide] ethylmorpholine;
N- (2-dimethylamino) ethylcrotonic acid amide, N- (2-diethylamino) ethylcrotonic acid amide, N- (2-di-n-propylamino) ethylcrotonic acid amide, N- (3-dimethylamino) Tertiary amino group-containing crotonic acid amides such as propylcrotonic acid amide and N- (4-dimethylamino) butylcrotonic acid amide;
Tertiary amino group-containing vinyl ethers such as 2-dimethylaminoethyl vinyl ether, 2-diethylaminoethyl vinyl ether, 3-dimethylaminopropyl vinyl ether, 4-dimethylaminobutyl vinyl ether;
Etc.

Examples of the vinyl monomer having an ether group include polyether chains such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene higher fatty acid ester, polyoxyethylene-polyoxypropylene block copolymer, and the like. Vinyl ether, allyl ether, or (meth) acrylic acid vinyl monomer having
Etc. A commercially available product may be used as the vinyl monomer having an ether group. Commercially available vinyl monomers having an ether group include, for example, Bremer PE-90, PE-200, PE-350, PME-100, PME-200, PME-400, AE-350 (above, Nippon Oil & Fats Co., Ltd.) Manufactured, trade name), MA-30, MA-50, MA-100, MA-150, RA-1120, RA-2614, RMA-564, RMA-568, RMA-1114, MPG130-MA (above, Japanese emulsifier) Company name, product name).
Here, the number of oxyethylene units in the polyoxyethylene chain is preferably 2 to 30. If this number is less than 2, the resulting oil / water separation filter tends to have insufficient flexibility, and if it exceeds 30, the oil / water separation filter becomes excessively soft and tends to have poor blocking resistance.

  As a vinyl monomer which has an amide group, N-alkyl or N-alkylene substituted (meth) acrylamide etc. are mentioned, for example. Specifically, for example, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N-ethylmethacrylamide N-methyl-N-ethylacrylamide, N-methyl-N-ethylmethacrylamide, N-isopropylacrylamide, Nn-propylacrylamide, N-isopropylmethacrylamide, Nn-propylmethacrylamide, N-methyl- Nn-propylacrylamide, N-methyl-N-isopropylacrylamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylhexahydride Azepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, N-vinylacetamide, diacetone acrylamide, Examples include diacetone methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide.

  As a vinyl monomer which has an epoxy group, a glycidyl group containing vinyl monomer etc. are mentioned, for example. Specific examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate, allyl glycidyl ether, allyl dimethyl glycidyl ether, and the like.

  Examples of the vinyl monomer having a sulfonic acid group include vinyl sulfonic acid.

Examples of vinyl monomers that do not have any of the above functional groups include alkyl methacrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate;
Conjugated dienes such as butadiene and isoprene;
Vinyl aromatic compounds such as styrene, α-methylstyrene, vinyl naphthalene;
Etc.

The recommended range of the copolymerization ratio of each vinyl monomer in the b2 component is as follows when the total amount of the b2 component is 100% by mass.
Vinyl monomer having a hydroxyl group: preferably 0.01 mass% to 50 mass%, more preferably 0.1 mass% to 20 mass%
Vinyl monomer having a carboxyl group: preferably 0.01% by mass to 20% by mass, more preferably 0.1% by mass to 5% by mass
Vinyl monomer having an amino group: preferably 0.01% to 50% by weight, more preferably 0.1% to 20% by weight
Vinyl monomer having an ether group: preferably 20% by mass to 70% by mass, more preferably 40% by mass to 60% by mass
Vinyl monomer having an amide group: preferably 30% by mass to 80% by mass, more preferably 45% by mass to 65% by mass
Vinyl monomer having an epoxy group: preferably 0.01% by mass to 50% by mass, more preferably 0.05% by mass to 20% by mass
Vinyl monomer having a sulfonic acid group: preferably 0.01% by mass to 20% by mass, more preferably 0.1% by mass to 5% by mass
Vinyl monomer having none of the above functional groups: preferably 20% by mass to 70% by mass, more preferably 40% by mass to 60% by mass

The preferred non-fluorinated hydrophilic material (B) in the present embodiment can be obtained by polymerizing or copolymerizing the vinyl monomer in the presence of the b1 component. In this case, the use ratio of the b1 component is preferably 10 to 100 parts by mass, and preferably 30 to 80 parts by mass with respect to 100 parts by mass in total of the vinyl monomers used for the synthesis of the b2 component. More preferably, it is more preferable to set it as 50 mass parts-60 mass parts.
The polymerization or copolymerization of the vinyl monomer can be performed by a known method using a radical, a cation, or an anion as an active species.

As the non-fluorine-based hydrophilic material (B) in the non-fluorine-based hydrophilic composition in the present embodiment, in addition to the polymer or copolymer obtained as described above, for example,
Superflex 126, 130, 150, 170, 210, 300, 420, 460, 470, 740, 800, 860, etc. manufactured by Daiichi Kogyo Seiyaku as anionic polyurethane particles; and NeoRez R-9660, R manufactured by DMS -972, R-9637, R-9679, R-989, R-2150, R-966, R-967, R-9603, R-940, R-9403 and the like;
Non-ionic polyurethane particles manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Superflex 500M, E2000, E4800, etc .;
Superflex 620, 650 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. may be used as the cationic polyurethane particles.

The non-fluorinated hydrophilic material (B) contained in the non-fluorinated hydrophilic composition in the present embodiment is preferably in the form of particles, and the number average particle diameter of the particles in an aqueous dispersion state is 10 nm to 800 nm. It is preferable. The number average particle diameter is more preferably 10 nm to 100 nm from the viewpoint of improving the durability of the oil / water separation filter in the present embodiment.
(B) The number average particle diameter of a component can be measured by the method as described in the below-mentioned Example.

(Hydrolyzable silicon compound (C))
As the hydrolyzable silicon compound (C) contained in the non-fluorinated hydrophilic composition in the present embodiment, the same as the b1 component contained in the non-fluorinated hydrophilic material (B) can be used,
Product names “KBE-402”, “KBM-803”, “KBM-802”, “KBE-403”, “KBM-303”, “KBM-1403”, “KBM-9659”, manufactured by Shin-Etsu Chemical Co., Ltd. Various silane coupling agents such as “KBM-585”, “KBM-846”, and “KBM-9007” may be used.

The hydrolyzable silicon compound (C) may be partly or wholly contained in the non-fluorine-based hydrophilic composition in the present embodiment in a state where it is hydrolyzed and condensed.
When the hydrolyzable silicon compound (C) is contained in the non-fluorinated hydrophilic composition as a hydrolysis condensate, the weight average molecular weight in terms of polystyrene is preferably 5,000 to 85,000, more preferably It is 8,000-80,000, More preferably, it is 10,000-50,000. When this weight average molecular weight is less than 5,000, the hydrophilicity of the oil / water separation filter may be inferior, and when it exceeds 85,000, the coating film on the oil / water separation filter becomes brittle and may be easily peeled off.
The said weight molecular weight can be measured on condition of the following using the GPC apparatus "HLC-8220GPC" by a Tosoh company, for example.
Column: TSKgel superAWM-H
Eluent: DMF (LiBr 5 mmol / L)
Sample volume 50 μl (1 mg / ml)
Detector: RI
Calibration curve: Created using standard polystyrene samples

(Metal oxide particles (D))
The non-fluorine-based hydrophilic composition in the present embodiment may contain metal oxide particles (D) together with the components (B) and (C), and preferably contains this. The metal oxide in this specification is a concept including silicon oxide.
The number average particle diameter of the component (D) is preferably 1 nm to 400 nm, more preferably 1 nm to 100 nm, still more preferably 3 nm to 80 nm, and particularly preferably 5 nm to 50 nm. This particle diameter means the number average particle diameter of the particles contained in the non-fluorinated hydrophilic composition, and is a measured value for the obtained composition. The particles may be a mixture of primary particles and secondary particles or only one of primary particles and secondary particles, and any of these may be used. (D) By making the number average particle diameter of a component into the said range, it can contribute to coexistence of hydrophilic property and oil repellency of this embodiment.
The number average particle diameter (hereinafter sometimes simply referred to as “particle diameter”) can be measured with a transmission microscope. Taking a transmission micrograph by adjusting so that 100 to 200 particles appear, and measuring the major axis and minor axis of about 10 to 20 particles randomly selected from the particles in the obtained image, The average value of all of them ((total of major axis + total of minor axis) / (number of measured particles × 2)) is adopted as the number average particle size.

(D) The metal oxide which comprises a component is not specifically limited, A well-known thing can be used. However, from the viewpoint of further increasing the interaction with the component (B) described above, for example, silicon dioxide, aluminum oxide, antimony oxide, titanium oxide, indium oxide, tin oxide, zirconium oxide, lead oxide, iron oxide, calcium silicate One or more selected from the group consisting of magnesium oxide, niobium oxide, and cerium oxide are preferred. Among these, from the viewpoint that there are many surface hydroxyl groups and the strength of the resulting oil / water separation filter can be improved, silicon dioxide (silica), aluminum oxide (alumina), zirconium oxide, antimony oxide, and composite oxides thereof. One or more selected from the group consisting of
The metal oxide particles (D) may be used alone or in combination of two or more.

The component (D) is preferably used for the preparation of a non-fluorine-based hydrophilic composition in the form of a powder, dispersion, sol or the like.
The “dispersion liquid” and “sol” as used herein are preferably 0.01 to 80% by mass in a dispersion medium in which the component (D) is composed of water or a mixed solvent of water and a hydrophilic organic solvent. More preferably, it means a state of being dispersed as at least one of primary particles and secondary particles at a concentration of 0.1 to 50% by mass.

As acidic colloidal silica using water as a dispersion medium, commercially available products such as Snowtex (trademark) -O, Snowtex-OS, Snowtex-OL, Lightstar (trademark) manufactured by Nissan Chemical Industries, Ltd .; Asahi Examples include Adelite (trademark) AT-20Q manufactured by Denka Kogyo Co., Ltd .; Clebosol (trademark) 20H12, Clevosol 30CAL25 manufactured by Clariant Japan, and the like.
Examples of basic colloidal silica using water as a dispersion medium include silica stabilized by addition of alkali metal ions, ammonium ions, or amines. Examples of the commercially available products include Snowtex-20, Snowtex-30, Snowtex-C, Snowtex-C30, Snowtex-CM40, Snowtex-N, Snowtex-N30, Snow, manufactured by Nissan Chemical Industries, Ltd. Tex-K, Snowtex-XL, Snowtex-YL, Snowtex-ZL, Snowtex PS-M, Snowtex PS-L; Adelite AT-20, Adelite AT-30, Adelite AT- from Asahi Denka Kogyo Co., Ltd. 20N, Adelite AT-30N, Adelite AT-20A, Adelite AT-30A, Adelite AT-40, Adelite AT-50; Crevozole 30R9, Crevozol 30R50, Clevozol 50R50 manufactured by Lariant Japan, Ludox (trademark) H manufactured by DuPont -40, Ludox HS-30, Ludox LS, include Ludox SM-30 and the like.

As colloidal silica using a hydrophilic organic solvent as a dispersion medium, commercially available products such as MA-ST-M (methanol dispersion type having a number average particle size of 20 nm to 25 nm), IPA-ST (several) are available. Isopropyl alcohol dispersion type having an average particle diameter of 10 nm to 15 nm), EG-ST (ethylene glycol dispersion type having a number average particle diameter of 10 nm to 15 nm), EG-ST-ZL (ethylene glycol dispersion type having a number average particle diameter of 70 nm to 100 nm) And NPC-ST (ethylene glycol monopropyl ether dispersion type having a number average particle diameter of 10 nm to 15 nm).
The various colloidal silicas described above may be used alone or in combination of two or more.

(Use ratio of each component in non-fluorinated hydrophilic composition)
The use ratio of the component (D) described above is preferably 50/100 to 10 from the viewpoint of hydrophilicity and strength as the mass ratio ((D) / (B)) of the component (D) to the component (B). 1,000 / 100, more preferably 110/100 to 1,000 / 100, and still more preferably 150/100 to 300/100. By setting the use ratio of the component (D) within the above range, the hydrophilicity, oil repellency, and strength of the obtained oil / water separation filter can be further improved.
The use ratio of the component (D) is preferably 10/100 to 10,000 / 100, more preferably as the mass ratio of the component (D) to the component (C) ((D) / (C)). Is 50/100 to 1,000 / 100, more preferably 80/100 to 250/100. By making the use ratio of component (D) to component (C) within this range, the hydrophilicity and oil repellency of the obtained oil / water separation filter will be strengthened, and hydrophilicity and oil repellency can be maintained even in flowing water, and erosion resistance Can be improved.
The solid content concentration of the non-fluorinated hydrophilic composition is preferably adjusted to 10% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 70% by mass or less.

[Manufacture of oil-water separation filter]
The oil / water separation filter in the present embodiment can be produced by applying a non-fluorinated hydrophilic composition to the substrate (A) described above, and then preferably aging.
As a coating method, an appropriate method such as a dip coating method (dipping method), a spray coating method, or a gravure coating method may be employed. Among these, a dip coating method or a spray coating method capable of allowing the composition to penetrate into the interior of the decorative fabric constituting the substrate (A) is preferable.
The curing temperature is preferably 20 ° C. to 200 ° C., more preferably 40 ° C. to 150 ° C., and still more preferably 50 to 90 ° C. When the curing temperature exceeds 200 ° C., the base (A) may be deteriorated, resulting in a large energy loss in the production process. When the curing temperature is less than 20 ° C., the productivity of the oil / water separation filter is inferior, and the resulting filter may vary in the performance such as durability.
The curing time is preferably 1 minute to 60 minutes, more preferably 5 minutes to 30 minutes.
Basis weight of the composition (coating amount) is, as the mass after curing per unit area of the substrate ^(A), is preferably in the be ^{~ 0.1g / m 2 ~20g / m} 2, more preferably 0.25g / M ^{2 to} 10 g / m ² .

[Characteristics of oil / water separation filter]
The oil-water separation filter in the filtration part in this embodiment is composed of the above-described nonwoven fabric (preferably a nonwoven fabric subjected to hydrophilic treatment).
The wetting tension of the oil / water separation filter is 25.4 mN / m or less. This wetting tension is an index indicating the hydrophilicity of the oil / water separation filter, and the lower this value, the higher the hydrophilicity. The wetting tension of 25.4 mN / m or less in the oil / water separation filter means that the oil / water separation filter has extremely high hydrophilicity. Thus, the oil / water separation filter can exhibit a sufficiently large water permeability suitable for practical use.

  The wetting tension of the oil / water separation filter can be examined using a wet tension test mixture. Each wetting tension test mixture has a specific wetting tension value. If a specific mixture can be uniformly applied onto the test piece, the test piece has the value specified in the mixture. It can be seen that it has the following wetting tension: Therefore, the oil / water separation filter according to the present invention can uniformly apply the wet tension test mixed liquid whose wet tension value is specified as 25.4 mN / m. For example, “Wet tension test mixed solution No. 25.4” manufactured by Wako Pure Chemical Industries, Ltd. may be used as a liquid mixture for wetting tension test for examining whether or not the wet tension is 25.4 mN / m or less. Etc.

The oil-water separation filter preferably has a hexadecane contact angle of 5 ° or more after sufficiently impregnating it with water. The greater the hexadecane contact angle value, the higher the oil repellency. By using an oil / water separation filter having a hexadecane contact angle of 5 ° or more, oil can be trapped with high efficiency from the oil / water mixture supplied onto the oil / water separation filter. Can be recovered and reused. The hexadecane contact angle after sufficiently impregnating the oil-water separation filter with water is more preferably 10 ° or more, and further preferably 15 ° or more.
The hexadecane contact angle after sufficient water impregnation can be measured using a contact angle meter. For example, a drop of hexadecane (1.0 μL) is placed on the surface of an oil-water separation filter sufficiently impregnated with water and allowed to stand at 25 ° C. for 10 seconds. Can be measured.

  As will be described later, it is preferable that the oil / water separation filter of the present embodiment operates in a state where at least a part thereof is submerged in the liquid to be treated. Therefore, it is preferable that the filter can be submerged stably in the operating state. In this respect, the specific gravity of the oil / water separation filter is preferably more than 1. Therefore, the nonwoven fabric constituting the oil / water separation filter is preferably made of polyester, glass, or polyamide. When the nonwoven fabric is composed of these resins, it is preferable in that it can be fused by heat or can be easily formed into a bag shape using a heating device such as a normal seal bar.

<Configuration of filtration unit>
The filtration part of the water purifier in this embodiment has a function of filtering the liquid to be treated by the oil / water separation filter as described above to give filtered water.
As long as the above function can be expressed, the structure and configuration of the filtration part are not particularly limited.
For example, a suitable housing having at least one opening serving as a liquid inlet and at least one opening serving as a filtrate outlet, and having a structure in which fluid flows in from the inlet and is discharged from the outlet The oil / water separation filter may be disposed inside. Here, the to-be-processed liquid which flowed in from the said inlet_port | entrance is discharged | emitted from the said outlet as the filtrate which passed the said oil-water separation filter. It is preferable from a viewpoint of the efficiency of oil-water separation that the filtration part in this embodiment does not have the path | route which can distribute | circulate fluid other than the surface of an oil-water separation filter.

Each of the liquid inlet and the filtrate outlet may be only one or may be composed of a plurality. For example, a case where one or a plurality of holes are formed in a plane, a case where a mesh-like housing is used, and the like are also included in the scope of the present embodiment.
As the shape of the filter housing, for example, a cylindrical shape, a polyhedron shape, a disk shape, a spherical shape, an elliptical shape, a tube shape, a spiral shape, and the like can be adopted without limitation as long as the fluid can circulate therethrough. it can.
The shape of the oil / water separation filter can be, for example, a flat membrane type, a bag type, a pleat type, a hollow tube, etc., and a cartridge type in which a plurality of these oil / water separation filters are packaged. It doesn't matter. A mode in which a plurality of these oil-water separation filters are arranged in multiple stages can also be preferably employed. In this case, the liquid to be treated that flows from the inlet is discharged from the outlet as a filtrate that has passed through a plurality of oil-water separation filters. An oil / water separation filter cartridge in which one or more of these are packaged can also be preferably used.
When the filtration part in this embodiment comprises a some oil-water separation filter, each filter may be the same kind and the kind of each filter may differ.

More specifically, for example, the following shapes can be exemplified as the filtration unit in the present embodiment:
A system in which a flat membrane-like oil-water separation filter is arranged in the vicinity of the axial center of a cylindrical housing that is open at both ends, perpendicular to the axial direction of the cylinder;
A system in which a pleated oil-water separation filter is arranged in the vicinity of the axial center of a cylindrical housing that is open at both ends, perpendicular to the axial direction of the cylinder;
A system in which one or a plurality of holes are provided in a cylindrical body portion that is open at one end and closed at the other end, and a bag-like oil-water separation filter is disposed so as to cover the inner surface of the cylinder;
When installing an oil / water separation filter fixed in a flat surface by a ring-shaped holder inside the pipe;
Etc., and combinations thereof.

As an oil-water separation system, for example, any filtration system such as natural filtration (gravity filtration), pressure filtration, reduced pressure filtration, centrifugal filtration, or the like can be employed.
However, if importance is placed on the efficiency of oil / water separation, it is preferable to perform separation by the form of natural filtration. Particularly preferably, the filtration part is
The liquid to be treated and the filtrate are adjacent via the oil / water separation filter,
This is a case where the liquid level of the liquid to be processed is maintained higher than the liquid level of the filtrate, and the liquid to be processed is filtered. In this case, at least a part of the oil / water separation filter is submerged in the liquid, and the difference in gravity caused by the difference in level between the liquid level of the water to be treated and the liquid level of the filtrate is driven through the oil / water separation filter. As a force, oil and water are separated by natural filtration.
In order to maintain the liquid level of the liquid to be treated higher than the liquid level of the filtrate, for example, a method of adjusting the introduction water pressure or the amount of the water to be treated or both of them while monitoring the height of both water surfaces A method of adjusting the volume of the treatment liquid reservoir, a method of controlling the amount of moving water by providing a valve at the treatment liquid inlet or the filtrate outlet or both of them can be used.

The filtration part in the water purification system of this embodiment not only separates the liquid phase and solid phase in the water to be treated, but also separates incompatible substances in the liquid phase.
In the treatment of accompanying water or the like, the oil phase in the liquid phase is separated from water by gravity separation, and the solid phase is separated by filtration. However, in the prior art, there are few methods that can separate the aqueous phase, the oil phase, and the solid phase all at once with one apparatus. Forcibly separating the water to be treated using a filter in the prior art, the solid phase that has taken in the oil phase adheres to the surface of the filter, resulting in clogging of the filter and a significant decrease in water permeability. Is known. In particular, when the particle size of the solid phase is small, clogging is enormous and the frequency of filter replacement increases, or the separation itself by filtration is abandoned.

However, in the present embodiment, an oil / water separation filter having high hydrophilicity is used, and at least a part of the filter is submerged. As a result, the oil phase and the solid phase float in the liquid to be treated in the vicinity of the filter. Therefore, these oil phase and solid phase do not adhere to the filter surface, and only the aqueous phase can be preferentially filtered.
In particular, the method of the present embodiment is effective for the purification of water to be treated containing an aqueous phase composed of at least two or more incompatible substances, an oil phase, and a solid phase having a specific gravity of 5 g / cm ³ or less. It is. It is preferable that the density of each substance in the water to be treated is in the order of oil phase <water phase <solid phase. From the viewpoint of enabling operation in a state where at least a part of the oil / water separation filter is stably submerged, the density of each substance in the oil / water separation filter and the water to be treated is: oil phase <water phase <oil / water separation filter <solid phase. More preferably. More preferably, it is as follows.
Specific gravity of oil phase: 1 g / cm ³ or less Specific gravity of water phase: 1 g / cm ^{3 to} 1.25 g / cm ³
Specific gravity of oil / water separation filter: 1 g / cm ^{3 to} 2 g / cm ³
Specific gravity of solid phase: 1 g / cm ^{3 to} 6 g / cm ³

  In order to operate stably in a state where at least a part of the oil / water separation filter is submerged, the difference in gravity caused by the introduced water pressure or the amount of water to be treated or both of them may be used, or suitable for the oil / water separation filter. It may be used with a weight attached.

In the water purifier of this embodiment, the supply amount of water to be treated to the filtration unit is preferably 10 to 10,000 L / (m ² · min) per unit time per unit area of the oil / water separation filter, More preferably, it is 50 to 5,000 L / (m ² · min). By setting the supply amount within this range, both high separation efficiency and high water permeability can be achieved.

The filtration part in the water purification apparatus of this embodiment selectively permeate | transmits only the water phase of the to-be-processed water supplied, and outputs the filtrate from which the oil component and the solid phase were removed. At this time, the oil-water separation filter has high hydrophilicity, and at least part of the filter is submerged, so that the oil phase and fine solid phase do not accumulate on the filter surface, and the output of filtrate is stable. Can be done.
The oil phase in the liquid to be treated is trapped by the oil / water separation filter and does not pass through the filter. The oil phase trapped on the filter does not adhere to the filter due to the oil repellency of the oil / water separation filter, and is captured as oil droplets on the surface to be treated. Since these oil droplets gather to form an oil layer as the amount of water to be treated increases, it can be recovered and reused. This is one of the advantageous features of the present invention.

In FIG. 4, an example of the structure of the filtration part in the water purifier of this embodiment was shown (cross-sectional view).
The filtration part of FIG. 4 is provided with the to-be-processed liquid inlet and the filtrate outlet, and the structure which installed the oil-separation filter bag-formed in the bag shape which has an opening part in the tank which consists of a housing which has a rectangular cross-sectional shape. Have The inside of the tank is divided into two parts, the inside of the bag and the outside of the bag, by an installed bag-like oil / water separation filter.
A liquid to be treated such as accompanying water is supplied to the opening of the bag-like oil / water separation filter through the inlet of the liquid to be treated, thereby forming a liquid reservoir to be treated inside the filter bag. The aqueous phase of the liquid to be treated in the liquid reservoir to be treated becomes the filtrate that has passed through the oil / water separation filter, and forms a filtrate reservoir in the tank outside the filter bag. The filtrate reaching the height of the filtrate outlet is output from the outlet.
At this time, by controlling the liquid level of the liquid reservoir to be processed to be higher than the height of the filtrate reservoir, it is possible to perform natural filtration due to a difference in gravity.
It is also a preferable aspect of the present embodiment that before the operation is started, the supply of the liquid to be processed is started after water is added to both the liquid reservoir and the filtrate reservoir to a desired liquid height. .

The water purification apparatus of the present embodiment can be suitably applied to the purification of associated water calculated in, for example, drilling of oil, coal, gas, and the like, and more preferably, the oil content contained in the accompanying water is recovered and recycled. It is also suitably applied to use.
Here, the accompanying water supplied as the water to be treated is, for example, pretreated using a known oil separation device such as a gravity separation type or a coalescer type, and then supplied to the filtration unit in the present embodiment. It is preferable from the viewpoint of efficient oil-water separation. According to this preferred embodiment, for example, even in the case of accompanying water containing about 40% by mass of oil, the amount of oil can be reduced to about 100 ppm.

<< Distillation part >>
As described above, the filtrate output from the filtration unit in the present embodiment has an oil content reduced as much as possible. However, when the to-be-processed liquid supplied contains a water-soluble salt, the said filtration part does not have the capability to remove this salt effectively. The accompanying water usually contains a water-soluble salt.
Therefore, it is preferable that the filtrate from which the oil has been removed by the filtration section (preferably after pretreatment by a known oil separator) is further purified.
Accordingly, the present invention provides a water purifier comprising the above-described filtration unit and distillation unit connected to each other. This distillation part has a function for distilling the filtrate produced | generated by the filtration part, and removing a solute from this filtrate.
It is preferable that the distillation part in the water purifier of this embodiment consists of a distillation system or a membrane distillation system. As the distillation system and the membrane distillation system, known modes can be employed, respectively.
Among these, it is particularly preferable to employ a membrane distillation system because of the simplicity of the apparatus and the purity of purified water.

<Membrane distillation system>
The membrane distillation system as a distillation unit in this embodiment includes at least a filtrate evaporation unit and a recovery unit. The filtrate evaporating unit has a function of evaporating the filtrate heated to a high temperature and generating water vapor separated from the oil contained in the filtrate; the recovery unit is generated in the filtrate evaporating unit It has a function to collect the steam. And between the said filtrate evaporation part and a collection | recovery part is isolated by the at least 1 film | membrane, and avoids the recontact of the collect | recovered purified water and the filtrate containing an oil component.
An example of the configuration of the membrane distillation system in the present embodiment will be described below with reference to the drawings as necessary.
The schematic diagram for demonstrating the system of the membrane distillation system applicable to this embodiment was shown to Fig.1 (a)-(d).

The membrane distillation system of FIG. 1 (a) is a DCMD method (Direct Contact Membrane Distribution). In the DCMD method,
In the evaporation section on the left side of the figure, water vapor generated by heating the treatment liquid (in this embodiment, the filtrate, the same applies hereinafter in the description of the membrane distillation system) to a high temperature,
Move to the collection part on the right side of the figure through the hydrophobic porous membrane 1,
In this collection part, it contacts with low temperature water (cooling water), liquefies, and takes in and collects in this low temperature water.

The membrane distillation system in FIG. 1 (b) is an AGMD method (Air Gap Membrane Distillation). The AGMD method has a structure in which a cooling body 2 is provided in addition to the hydrophobic porous membrane 1, and a gas phase portion (gas phase portion 3) is provided therebetween. In this type of membrane distillation system,
In the evaporation part on the left side of the figure, water vapor generated by heating the treatment liquid to a high temperature,
Moved through the hydrophobic porous membrane 1 to the gas phase 3 at the center of the figure,
In the recovery part on the right side of the figure, the purified water liquefied by condensing the water vapor on the surface of the cooling body 2 cooled by the low temperature water is recovered. Here, the cooling body 2 is preferably made of a material having a high thermal conductivity and impervious to water vapor. As the cooling body 2, for example, a metallic cooling plate can be exemplified, and preferably an aluminum plate or a stainless steel plate.

The membrane distillation system of FIG. 1C is a VMD method (Vacuum Membrane Distillation). In the VMD method,
In the evaporation section on the right side of the figure, water vapor generated by heating the treatment liquid to a high temperature,
Move to the collection part on the right side of the figure through the hydrophobic porous membrane 1,
By applying a vacuum or reduced pressure to the recovery unit, the moved water vapor is taken out of the system without being liquefied and recovered as purified water.

  The membrane distillation system in FIG. 1 (d) is an SGMD method (Sweeping Gas Membrane Distillation). The SGMD method is the same as the VMD method shown in FIG. 1 (c), except that the sweeping gas is flowed instead of applying a vacuum or reduced pressure to the recovery unit, so that the water vapor that has moved to the recovery unit is taken out of the system without being liquefied. In addition, it is a method of collecting as purified water. As the sweeping gas, a gas inert to water and having a boiling point lower than that of water is preferable. Specifically, for example, dry air, nitrogen, or the like is preferably used.

As the distillation recovery means in the membrane distillation system, it is desirable to use any one of the DCMD method, the AGMD method, the VMD method, and the SGMD method according to the required water quality of the purified water and the required amount of water production.
The specific specification of the distillation part preferably employed in the water purifier of this embodiment will be described below by taking as an example the case of using the VMD method as the distillation recovery means.

The distillation unit in the water purifier of this embodiment is at least:
A liquid phase part 1 where the filtrate exists, and a filtrate evaporation part consisting of a hydrophobic porous membrane in contact with the liquid phase part 1;
A liquid phase part 2 through which cooling water flows, and a recovery part comprising a cooling body adjacent to the liquid phase part 2;
A gas phase unit 3 connecting the filtrate evaporation unit and the recovery unit;
Is preferably a membrane distillation system.
More preferably,
The filtrate evaporating part further has a gas phase part 1 on the side opposite to the liquid phase part 1 of the hydrophobic porous membrane,
In the recovery unit, when the gas phase unit 2 is further provided on the side opposite to the liquid phase unit 2 of the cooling body, and the gas phase unit 1 and the gas phase unit 2 are connected by the gas phase unit 3 It is. This latter aspect, in other words,
A filtrate evaporating part in which the liquid phase part 1 where the filtrate is present and the gas phase part 1 are adjacent to each other via a hydrophobic porous membrane;
A liquid phase part 2 through which cooling water flows, a gas phase part 2 adjacent to each other via a cooling body, and a gas phase part 3 connecting the gas phase part 1 and the gas phase part 2
It can be expressed as a membrane distillation system comprising:

[Hydrophobic porous membrane]
The hydrophobic porous membrane used in the distillation section of the present embodiment is not particularly limited as long as it is a porous membrane produced by a conventionally known method and comprising a hydrophobic polymer as a main constituent component. The phrase “hydrophobic polymer as a main constituent” means that 90% by mass or more of the hydrophobic polymer is contained with respect to the total mass of the material constituting the hydrophobic porous membrane. From the viewpoint of increasing the strength of the membrane, the content ratio of the hydrophobic polymer to the total mass of the material constituting the hydrophobic porous membrane is preferably 95% by mass or more, and preferably 99% by mass or more. More preferred.
Examples of the hydrophobic polymer include polysulfone, polyethersulfone, polyethylene, polypropylene, polyvinylidene fluoride, and polytetrafluoroethylene.

Examples of the shape of the hydrophobic porous membrane include a flat membrane type, a tubular type, a hollow fiber type, and a spiral type. From the viewpoint of making the membrane module compact, a hollow fiber membrane that can take a large membrane area per unit volume is preferable.
The hydrophobic porous membrane of this embodiment preferably has a surface porosity of 20% or more on the membrane surface in contact with the filtrate. The membrane preferably has an air permeability coefficient of 7.0 × 10 ⁻⁷ m ³ / m ² · sec · Pa or more on the membrane surface in contact with the water to be treated.
By using a membrane having a surface porosity and an air permeation coefficient on the membrane surface in contact with the filtrate in the above ranges, both the evaporation efficiency and the water vapor transmission rate can be increased, and the flux can be remarkably increased. Evaporation efficiency is considered to increase due to the high surface porosity of the membrane surface in contact with the filtrate. It is considered that the water vapor transmission rate is increased by using a membrane having a high air permeability coefficient.
In the present embodiment, the surface porosity of the surface of the hydrophobic porous membrane in contact with the filtrate can be measured by analyzing an electron microscope image with image analysis processing software. Specifically, it can be performed by the method described in the examples described later.

In order to increase the water vapor transmission rate of the membrane, it is considered that the membrane structure is generally sparse and homogeneous. If the surface porosity of the membrane surface (opposite surface) opposite to the membrane surface in contact with the filtrate approximates the surface porosity of the membrane surface in contact with the filtrate, the membrane structure as a whole is homogeneous. It is believed that there is. Therefore, it is preferable that the surface porosity of the membrane surface in contact with the filtrate is in the above range and that the surface porosity of the opposite surface is high from the viewpoint of increasing the water vapor transmission rate.
Specifically, the hydrophobic porous membrane in the present embodiment has a surface porosity of 20% or more on the opposite surface in addition to the surface porosity of the membrane surface in contact with the filtrate being 20% or more. Preferably there is. From the viewpoint of increasing the mechanical strength of the membrane and from the viewpoint of preventing water leakage during use under reduced pressure, the surface open area ratio on the opposite surface is preferably 70% or less, and more preferably 35% or less. . It is preferable that the surface opening ratio of the opposite surface is 20% or more and 70% or less. The surface area ratio of the opposite surface can be measured in the same manner as the surface area ratio of the surface in contact with the filtrate.

From the viewpoint of improving the water permeability in membrane distillation in the present embodiment, the air permeability coefficient of the hydrophobic porous membrane is 7.0 × 10 ⁻⁷ m ³ / m ² · sec · Pa or more. preferable. From the viewpoint of increasing the mechanical strength of the membrane and preventing water leakage during use under reduced pressure, the air permeability coefficient of the hydrophobic porous membrane is 1.0 × 10 ⁻⁵ m ³ / m ² · sec · It is preferably Pa or less, and more preferably 3.2 × 10 ⁻⁶ m ³ / m ² · sec · Pa or less.

  In the present embodiment, the air permeation coefficient of the hydrophobic porous membrane is defined as the amount of air permeated from the surface of the membrane in contact with the filtrate by pressurizing air at a constant pressure on the opposite surface of the hydrophobic porous membrane. It can be known by measuring using a meter. Specifically, it can be performed with reference to the methods described in the examples described later.

The hydrophobic porous membrane in the present embodiment preferably has an average pore size of 0.15 μm or more from the viewpoint of improving the water permeability during membrane distillation. In the present embodiment, the average pore diameter of the hydrophobic porous membrane is preferably 10 μm or less from the viewpoint of suppressing the “wetting phenomenon” in which water penetrates into the membrane due to a decrease in water repellency on the membrane surface. . The average pore size of the hydrophobic porous membrane can be measured by the average pore size measurement method described in ASTM F316-86 with reference to the method described in Examples.
In the present embodiment, the porosity of the hydrophobic porous membrane is preferably 60% or more, and more preferably 70% or more, from the viewpoint of improving the water permeability in the membrane distillation. From the viewpoint of maintaining the mechanical strength of the membrane and preventing water leakage when used under reduced pressure, the porosity of the hydrophobic porous membrane is preferably 90% or less. The porosity of the hydrophobic porous membrane can be measured with reference to the methods described in the examples.

In the present embodiment, the film thickness of the hydrophobic porous membrane is preferably 10 μm to 500 μm, preferably 15 μm to 300 μm, from the viewpoint of improving the water permeability in the membrane distillation and increasing the mechanical strength of the membrane. More preferably. When the film thickness is 500 μm or less, it is possible to suppress a decrease in water permeation performance with continued use. When the film thickness is 10 μm or more, deformation of the film and blockage of the flow path can be prevented during use under reduced pressure.
The thickness of the hydrophobic porous membrane can be measured by a micrograph of a cross section with reference to the method described in Examples.

  The hydrophobic porous membrane provided in the evaporation section may be, for example, a flat membrane shape or a hollow fiber shape.

The hollow fiber-like hydrophobic porous membrane has, for example, an outer diameter of 300 μm to 5,000 μm, preferably 350 μm to 4,000 μm, and an inner diameter of 200 μm to 4,000 μm, preferably 250 μm to 3 The size can be less than 1,000 μm. A plurality of hydrophobic porous hollow fiber membranes are bundled and stored in a cylindrical container, and at the end of the hollow fiber, the gap between the hollow fibers and the gap between the hollow fiber and the container are filled with a fixing resin (potting resin). It may be used as a hollow fiber package. As the material of the container, for example, resin, metal or the like can be used.
In the above package, the end of the hollow fiber membrane is open, and head portions having water passages may be attached to the upper and lower ends of the container. You may equip the side surface of a container with the connection port for connecting with a collection | recovery part. The number of connection ports is not particularly limited, and may be single or plural.

[Specific Embodiment of Membrane Distillation System]
The filtrate evaporating unit in the water purifier of the present embodiment includes at least a liquid phase part 1 through which the filtrate is passed, and a filtrate evaporating part composed of a hydrophobic porous membrane in contact with the liquid phase part 1;
A liquid phase part 2 through which cooling water flows, and a recovery part comprising a cooling body adjacent to the liquid phase part 2;
A gas phase unit 3 connecting the filtrate evaporation unit and the recovery unit;
Is preferably a membrane distillation system.
Hereinafter, as a preferable aspect of the present embodiment, a case where a flat membrane is used as the hydrophobic porous membrane and a case where a hollow fiber membrane is used are more specifically embedded.

FIG. 2A is a conceptual diagram illustrating the case of an integrated membrane distillation system using a flat membrane-like hydrophobic porous membrane.
The membrane distillation system of FIG. 2A includes a liquid phase part 1 through which a filtrate flows, and a filtrate evaporation part composed of a hydrophobic porous membrane in contact with the liquid phase part 1;
A liquid phase part 2 through which cooling water flows, and a recovery part comprising a cooling body adjacent to the liquid phase part 2;
A gas phase part 3 (air gap) connecting the filtrate evaporation part and the recovery part;
A water sampling container connected to a decompression device via a pressure regulator;
Is provided. The water sampling container is connected to the gas phase unit 3.
In the membrane distillation system of FIG. 2A, preferably, when the filtrate heated to a high temperature passes through the liquid phase part 1, a part thereof becomes water vapor and passes through the hydrophobic porous membrane to enter the gas phase part 3. Moving. At this time, the non-volatile solute (such as salt) cannot be passed through the membrane wall of the hollow fiber membrane, and is thus separated.
The pressure in the gas phase part 3 is adjusted to a range of preferably 1 kPa or more and the saturated vapor pressure of water or less at the filtrate temperature by a decompression device. A more preferable pressure of the gas phase part 3 will be described later. Accordingly, the water vapor that has moved to the gas phase unit 3 is condensed on the cooling body in the recovery unit to become liquid purified water, and is recovered in the water sampling container.

FIG. 2B is a conceptual diagram illustrating the case of an integral membrane distillation system using a hydrophobic porous membrane hollow fiber.
The membrane distillation system of FIG.
A filtrate evaporating part in which the liquid phase part 1 where the filtrate is present and the gas phase part 1 are adjacent to each other via a hydrophobic porous membrane;
A recovery unit in which a liquid phase part 2 through which cooling water flows and a gas phase part 2 are adjacent to each other via a cooling body;
A gas phase part 3 connecting the gas phase part 1 and the gas phase part 2, and a water sampling container connected to a pressure reducing device via a pressure regulator,
Is provided. The water sampling container is connected to the gas phase unit 2. The cooling body in this system is a cooling pipe.

In the membrane distillation system of FIG. 2B, since the filtrate flows through the internal space of the hydrophobic porous membrane hollow fiber, the hollow inner hole of the hollow fiber becomes the liquid phase part 1 in this system;
The outside of the hollow fiber is the gas phase portion 1.
Since the cooling water flows through the cooling pipe, the inside of the cooling pipe becomes the liquid phase part 2 in this system;
The outside of the cooling pipe is the gas phase part 2. The cooling pipe is preferably made of a material that does not allow the cooling water to leak to the outside of the pipe. For example, the cooling pipe can be made of non-porous metal, resin, or the like.
And the gas phase part 3 is arrange | positioned between the said gas phase part 1 and the said gas phase part 2, and has connected between both.

A part of the filtrate that has passed through the hollow lumen of the hydrophobic porous hollow fiber membrane becomes water vapor, passes through the membrane wall of the hollow fiber membrane, and moves to the gas phase portion 1. At this time, the non-volatile solute (such as salt) cannot be passed through the membrane wall of the hollow fiber membrane, and is thus separated.
The water vapor that has moved to the gas phase part 1 moves to the gas phase part 2 via the gas phase part 3.
And since the pressure of the gas phase parts 1 to 3 in the system of FIG. 2B is adjusted to a range of preferably 1 kPa or more and the saturated vapor pressure of water at the filtrate temperature by the decompression device, The moved water vapor condenses on the cooling body in the recovery unit to become liquid purified water, and is recovered in the water sampling container. (A more preferable pressure of the gas phase parts 1 to 3 will be described later.)

The recovery unit in the membrane distillation system of the present embodiment is, for example, for storing a plurality of cooling pipes in a cylindrical container, and fixing the gap between the cooling pipes and the gap between the cooling pipe and the container at the end of the cooling pipe. A cooling tube package formed by filling with resin (potting resin) and fixing the cooling tube to a container is used. As the material of the container, for example, resin, metal or the like can be used.
The end of the cooling pipe is open, and head portions having water passages may be attached to the upper and lower ends of the container. You may equip the side surface of a container with the connection port for connecting with an evaporation part. The number of connection ports is not particularly limited, and may be single or plural.
In the system of FIG. 2B, a hollow cooling pipe is used as a cooling body. However, instead of this cooling pipe, a cooling body on a flat plate may be used.

  The gas phase part 3 is a gas phase part having a function of connecting the gas phase part 1 and the gas phase part 2. The volume of the gas phase part 3 is preferably large from the viewpoint of water vapor transmission. The number of the gas phase parts 3 is not particularly limited, and may be single or plural. The shape may be cylindrical or polygonal. The member of the casing that defines the gas phase portion 3 is not particularly limited, and for example, resin, metal, or the like can be used. However, a highly heat-insulating material may be used so that water vapor does not condense in the gas phase portion 3, and this may be heat-insulated as necessary.

The gas phase part 3 is preferably provided so that the shortest distance between the hydrophobic porous membrane in the evaporation part and the cooling body in the recovery part is 10 mm or more. Here, the shortest distance between the hydrophobic porous membrane and the cooling body means the shortest linear distance between the closest portions of the hydrophobic porous membrane and the cooling body.
In the present embodiment, by setting the pressure in the gas phase part within a predetermined range, the restriction on the arrangement distance between the evaporation part and the recovery part in the membrane distillation system is relaxed, and the size of the gas phase part 3 is set as described above. It has become possible to reduce the size. By relaxing this distance, the degree of freedom in designing a membrane distillation module using a hydrophobic porous membrane is increased, and it becomes possible to save space and make the water purification system compact.
By setting the shortest distance to 10 mm or more, the evaporating part and the collecting part can be easily designed. This shortest distance may be 30 mm or more.
In the present embodiment, by setting the shortest distance to 10 mm or more, preferably 3 m or less, the degree of freedom in designing the evaporation unit and the recovery unit is increased, and at the same time, the above-described public range of the gas phase units 1 to 3 is controlled. By performing membrane distillation, a high-flux membrane distillation system is used in spite of its compactness without the need for high vacuum or sweep gas.

3A to 3C are examples of another embodiment using a hydrophobic porous membrane hollow fiber. In these systems, a hydrophobic porous hollow fiber membrane package similar to the system of FIG. 2B is used. However, since the filtrate is present outside the hydrophobic porous membrane hollow fiber, the outside of the hollow fiber becomes the liquid phase part 1 in this system;
The hollow inner hole of the hollow fiber becomes the gas phase portion 1.

  In the system of FIG. 3A, the entire hydrophobic porous hollow fiber membrane package is immersed in the filtrate (liquid phase part 1) in the filtrate tank, and these constitute the filtrate evaporation part. . The collection unit is substantially the same as the system shown in FIG. 2B, and the cooling pipe package is arranged vertically. And the gas phase part 1 of the said filtrate evaporation part and the gas phase part 2 of the said collection | recovery part are connected by the gas phase part 3 formed in piping. Two pipes constituting the gas phase part 3 extend from both ends of the hollow fiber membrane package, and both of them are the gas phase part 3 in the present system.

In this case, preferably, a part of the filtrate heated to a high temperature becomes water vapor, passes through the membrane wall of the hollow fiber membrane, and enters the gas phase portion 1 formed in the inner hole of the hollow fiber membrane. Moving. At this time, the non-volatile solute (such as salt) cannot be passed through the membrane wall of the hollow fiber membrane, and is thus separated.
The water vapor that has moved to the gas phase portion 1 moves to the gas phase portion 2 through the gas phase portion 3 in the pipe.
And since the pressure of the gas phase parts 1 to 3 in the system of FIG. 3A is adjusted to a range of preferably 1 kPa or more and the saturated vapor pressure of water at the filtrate temperature by the decompression device, The moved water vapor condenses on the cooling body in the recovery unit to become liquid purified water, and is recovered in the water sampling container. (A more preferable pressure of the gas phase parts 1 to 3 will be described later.)

Here, the filtrate tank means a place where the filtrate is present, and may be, for example, a water tank such as a pit or a part of the flow path of the filtrate.
When the filtrate tank is a water storage tank, the filtrate obtained in the filtration unit may be stored in the water storage tank, so that the installation space for the water purifier can be made compact. Furthermore, if the water level of the water storage tank is controlled to be constant, membrane distillation treatment can be performed under constant conditions, so that stable water purification efficiency can be obtained.
On the other hand, when the filtrate tank is a part of the filtrate flow path, it is easy to keep the membrane flow condition constant, but a large amount of filtrate is required.
In view of the above, the filtrate tank is preferably a water tank type and equipped with a control device that keeps the water level constant.

  The liquid phase part 1 may or may not be stirred. In order to prevent a decrease in the filtrate temperature due to the heat of vaporization when the filtrate becomes steam, and a decrease in the distillation rate due to this, it is preferable to stir the liquid phase part 1. As the stirring method, existing stirring methods such as propeller type stirring and circulation type stirring can be used.

  The membrane distillation system of FIG. 3B is an aspect in which the cooling pipe package as the collection unit is horizontally arranged in the system of FIG. 3A. The other aspects are substantially the same as in FIG. 3A.

  The membrane distillation system of FIG. 3C is a mode in which only one pipe constituting the gas phase portion 3 extends from one end of the hollow fiber membrane package in the system of FIG. 3A. The other aspects are substantially the same as in FIG. 3A.

In any of the above systems, the filtrate may be supplied to the liquid phase unit 1 after being heated by a heat source such as a heat exchanger or a heater and stored in a filtrate tank as a high-temperature filtrate. It is more preferable to control the temperature of the filtrate by utilizing solar heat or exhaust heat from an industrial process or the like because the thermal energy cost required for heating can be eliminated or reduced.
The temperature of the filtrate supplied to the liquid phase part 1 is preferably 50 ° C. or higher, and more preferably 80 ° C. or higher, from the viewpoint of water permeability.

In the present embodiment, the cooling water is not particularly limited as long as it is a liquid that can flow through the liquid phase portion 2 and cool the water vapor. For example, tap water, industrial water, river water, well water, lake water, sea water, industrial wastewater (waste water from food factories, chemical factories, electronics industry factories, pharmaceutical factories, cleaning factories, etc.), oil or natural gas production The accompanying water discharged at times is mentioned.
In the present embodiment, the filtrate itself may be used as cooling water.
The cooling water preferably has a water temperature of 30 ° C. or less from the viewpoint of recovery efficiency.
The water temperature of the cooling water may be controlled by utilizing a heat source such as a heat exchanger or a heater.

  The pressure of the gas phase part 3 in the system of FIG. 2A and the gas phase parts 1 to 3 in the system of FIGS. 2B and 3A to C is between 1 kPa and the saturated vapor pressure of water at the filtrate temperature as described above. It is preferable to be controlled. That the pressure of the gas phase parts 1 to 3 is equal to or lower than the saturated vapor pressure of water at the treated water temperature, the water temperature of the filtrate supplied to the liquid phase part 1 It means to control the pressure below the saturated vapor pressure (theoretical value).

  By suppressing the pressure of the gas phase part 3 in the system of FIG. 2A and the gas phase parts 1 to 3 in the systems of FIGS. 2B and 3A to 1C to 1 kPa or more, excessive energy consumption required for decompression of the decompression device is suppressed. Can do. By setting this pressure below the saturated vapor pressure of water at the filtrate temperature, high water permeability can be realized. From the viewpoint of energy consumption, the pressure is preferably 1 kPa or more, and more preferably 10 kPa or more. From the viewpoint of water permeability, the pressure is preferably not more than the saturated vapor pressure of water at the filtrate temperature, more preferably not more than 5 kPa lower than the saturated vapor pressure of water at the filtrate temperature, and the filtrate temperature. More preferably, the pressure is 10 kPa or lower than the saturated vapor pressure of water.

For adjusting the pressure of the gas phase part 3 in the system of FIG. 2A and the gas phase parts 1 to 3 in the systems of FIGS. 2B and 3A to C to the above pressure range,
Examples of the decompression device include a diaphragm vacuum pump, a dry pump, an oil rotary vacuum pump, an ejector, and an aspirator;
Examples of the pressure control method include a method using a vacuum regulator, a method using a leak valve, a method using an electronic vacuum controller and an electromagnetic valve, and the like.
The pressure is preferably adjusted while being monitored by a pressure gauge. The pressure may be monitored as the total pressure of the gas phase sections 1 to 3, the water sampling container, the pressure regulator, and the piping connecting them.

  The purified water further purified by the membrane distillation system in the water purification apparatus of the present embodiment has an extremely reduced water-soluble salt concentration. Therefore, a very substantial water purification system can be obtained by using the filtration unit and the membrane distillation system in combination.

  EXAMPLES Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described. However, the present invention is not limited to the following examples and the like.

<Example 1>
1. Synthesis of non-fluorinated hydrophilic material After charging 1,600 g of ion-exchanged water and 4 g of dodecylbenzenesulfonic acid into a reactor having a reflux condenser, a dropping tank, a thermometer, and a stirring device, the mixture was heated to 80 ° C. with stirring. Warm up.
A liquid mixture consisting of 185 g of dimethyldimethoxysilane and 117 g of phenyltrimethoxysilane was added dropwise over 2 hours while maintaining the temperature in the reaction vessel at 80 ° C., and the temperature was maintained at 80 ° C. for 1 hour. Stir.
Next, 150 g of butyl acrylate, 30 g of tetraethoxysilane, 145 g of phenyltrimethoxysilane, and 1.3 g of 3-methacryloxypropyltrimethoxysilane, 165 g of diethylacrylamide, 3 g of acrylic acid, and reactive emulsifier (product) The name “Adekaria soap SR-1025”, manufactured by Asahi Denka Co., Ltd., solid content 25% by weight aqueous solution) 13 g, ammonium persulfate 2% by weight aqueous solution 40 g, and a mixture of 1,900 g of ion-exchanged water in a reaction vessel. Were simultaneously added dropwise over 2 hours while maintaining the temperature of 80 ° C. Subsequently, stirring was performed for 4 hours while maintaining the temperature in the reaction vessel at 80 ° C.
Then, it cooled to room temperature and obtained the water dispersion containing 14 mass% of polymer emulsion particles (B-1) with a number average particle diameter of 131 nm by filtering with a 400 mesh metal-mesh.

2. Preparation of coating composition An aqueous dispersion containing (B-1) synthesized in step 1 and an aqueous dispersion colloidal silica having an average particle size of 5 nm as a metal oxide (D) (trade name “Snowtex OXS”, manufactured by Nissan Chemical Industries, Ltd., solid 10 mass%) and 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403) as a hydrolyzable silicon compound (C), and mixed with 20 mass% ethanol water. By adding and adjusting solid content concentration to 6 mass%, the coating composition was obtained.
The composition ratio of the coating composition was (D) / (B) / (C) = 100/100/10 as a mass ratio in terms of solid content. The hydrolyzable silicon compound (C) was contained in this coating composition as a hydrolysis condensate having a weight average molecular weight of 39,500. As the mass of the component (C), the composition ratio was calculated using a SiO ₂ converted value.

3. Production of oil-water separation filter (hydrophilic treatment and bag making)
N3007 manufactured by Asahi Kasei Fibers Co., Ltd. (nylon, basis weight 30 g / m ² , thickness 0.1 mm, fiber diameter 0.7 μm, average pore diameter 6 μm) as a nonwoven fabric substrate is immersed in the coating solution prepared above for 5 seconds at room temperature. And then dried at 80 ° C. for 15 minutes to obtain a hydrophilic nonwoven fabric. The coating amount after drying was 1 g / m ² .
The hydrophilized nonwoven fabric produced above was folded in half, and the sides and bottom were sealed by heat sealing to form a bag of 50 cm × 50 cm, which was used as an oil-water separation filter.
The non-woven fabric substrate used was made of nylon and could be made easily by heat sealing.

4). Measurement (1) Average Fiber Diameter The average fiber diameter of the oil / water separation filter was measured using a scanning electron microscope (SEM) manufactured by JEOL Ltd., model “JSM-6510”.
3. above. The hydrophilized nonwoven fabric obtained in (1) was cut into 10 cm × 10 cm, platinum was deposited, and this was used as an SEM observation sample.
SEM observation was performed under the conditions of an acceleration voltage of 15 kV and a working distance of 21 mm, and 100 or more fibers were randomly photographed. The fiber diameters of all the photographed fibers were measured, and the average fiber diameter was determined. At this time, when a plurality of fibers were fused in the yarn length direction, they were omitted from the measurement.

(2) Average pore size The average pore size of the oil / water separation filter was measured by Porous Materials, Inc. It was measured using a porous material automatic fine average pore size distribution measuring system (model “Automated Perm Porometer”).
3. above. The hydrophilized nonwoven fabric obtained in (1) was cut into a diameter of 25 mm with a punching blade, immersed in a GALWICK reagent at room temperature for 30 minutes, and then deaerated for 1 hour to prepare a measurement sample.
The measurement sample was set in the apparatus, and air pressure was applied. Then, the air pressure when the GALWICK reagent was pushed out by overcoming the liquid surface tension in the capillary was measured, the pore diameter was determined from the Washburn equation, and this value was taken as the average pore diameter.

(3) Wetting tension measurement (JIS K6768)
This test was conducted at a constant temperature of 23 ° C. environmental temperature.
3. above. The hydrophilized non-woven fabric obtained in the above (not made in a bag) is left flat on a laboratory desk, and a wet tension test mixed solution (Wako Pure Chemical Industries, Ltd., No. 25.4) is added. After dropping several drops, immediately using a cotton swab, the dropping solution was spread over the entire surface of the nonwoven fabric to form a coating film. Two seconds later, the central part of the coating film was visually observed.
As a result, the coating film was not torn and kept in its original state, so it was confirmed that the wetting tension of the hydrophilic nonwoven fabric was 25.4 mN / m or less.

5. Separation performance test Using the apparatus shown in FIG. A separation performance test of the oil-water separation filter (made in a bag. Area 0.5 m ² ) obtained in 1 was performed.
The portion of the “filtrate reservoir” in the tank was filled with tap water, a bag-formed oil / water separation filter was set, and the bag inside the oil / water separation filter was also filled with tap water. And as a processing liquid, the liquid mixture which consists of 10 mass% hexadecane 10 mass%, 85 mass% of salt solution, and 5 mass% of sand was introduce | transduced at the temperature of 25 degreeC, and the introduction speed of 5 L / min.
The specific gravity of the oil / water separation filter in this example was 1.13, and it could exist stably in the aqueous phase. The water surface of the liquid reservoir to be treated introduced from the upper surface of the bag made oil-water separation filter bag can be maintained higher than the water surface in the filtrate reservoir, thereby stably separating the treatment liquid continuously. I was able to. The height difference between the liquid height of the liquid reservoir to be treated and the liquid height of the filtrate reservoir was maintained in the range of 0.5 cm to 3 cm during operation.
The liquid to be treated contained an amount of oil such that the hexadecane layer was visible on the liquid surface. However, no hexadecane phase was observed in the filtrate phase that passed through the oil / water separation filter. An oil phase of hexadecane was formed on the liquid surface of the oil / water separation filter bag, and this could be recovered with a dropper. Sand accumulation was observed at the bottom of the oil-water separation filter bag.

6). Oilfield-associated water / oil separation Using the apparatus shown in FIG. The oil-water separation performance of the oil field-associated water was examined using the oil-water separation filter (made in bag, area 0.01 m ² ) obtained in 1.
The portion of “filtrate reservoir” in the tank and the inside of the bag of the oil / water separation filter were filled with a total of 50 mL of distilled water. Then, oil field-associated water (oil mixed water containing about 1.5 g / L of organic carbon and about 20 g / L of salt) was introduced as a liquid to be treated at a temperature of 25 ° C. and an introduction rate of 500 mL / min.
Also in this test, 5. In the same manner as above, oil and water could be separated stably, and 6 L of filtrate was obtained in 12 minutes. The height difference between the liquid height of the liquid reservoir to be treated and the liquid height of the filtrate reservoir was maintained in the range of 0.5 cm to 3 cm during operation.
The conductivity of the obtained filtrate was measured using an electric conductivity meter (manufactured by Horiba, Ltd., conductivity measuring instrument desktop type, model “DS-52”), and was 27.3 mS / cm.

7). Membrane distillation of filtrate (1) Measurement of various physical properties of hydrophobic porous hollow fiber membrane Hereinafter, methods for measuring various physical properties of the hydrophobic porous hollow fiber membrane used in this example will be described. By referring to each measurement method, various physical properties of an arbitrary hydrophobic porous membrane can be measured.

(Outer diameter and inner diameter, and film thickness)
The outer diameter and inner diameter of the hydrophobic porous hollow fiber membrane were measured by microscopic observation using a sample obtained by thinly cutting the hollow fiber membrane with a razor in a direction perpendicular to the longitudinal direction. The film thickness was determined as the difference between the outer diameter and the inner diameter.
(Porosity)
A sample obtained by cutting a hydrophobic porous hollow fiber membrane into a predetermined length (40 cm in this example) with a razor was used, and the mass of the sample was measured using an electronic balance. Using the values obtained here, the porosity was calculated by the following formula.

(Average pore diameter)
The average pore diameter of the hydrophobic porous hollow fiber membrane was measured according to the average pore diameter measurement method (also known as half-dry method) described in ASTM F316-86.
The measurement was performed by using a sample obtained by cutting a hydrophobic porous hollow fiber membrane to a length of about 10 cm, using ethanol as a liquid under standard measurement conditions of 25 ° C. and a pressure increase rate of 0.01 atm / second.
The average pore diameter is the following formula:
Average pore diameter [μm] = 2,860 × (surface tension of liquid used [dyne / cm]) / (half dry air pressure [Pa])
Surface tension of liquid used (ethanol) (25 ° C.) = 21.97 dyne / cm
Determined by

(Surface opening ratio)
The surface aperture ratio of the hydrophobic porous hollow fiber membrane was determined from each electron micrograph of the inner surface and outer surface of the membrane.
The inner surface and the outer surface of the hollow fiber membrane to be measured were each 5,000 magnifications at an acceleration voltage of 1.0 kV and secondary electron detection conditions using a scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.). Taken at ~ 50,000 times. Then, the surface porosity of the inner surface and outer surface of the hollow fiber membrane was determined by processing the obtained microscopic image with image analysis processing software “ImageJ” (free software). Holes on the measurement range boundary are not excluded from the calculation.
The surface aperture ratio is the following formula:
Surface aperture ratio [%] = 100 × (total sum of pore areas on inner and outer surfaces) / (total sum of area of measurement range)
I got it from the load.

を用いて空気透過係数を求めた。 (Air permeability coefficient)
The air permeability coefficient of the hydrophobic porous hollow fiber membrane was determined by the following method.
One hydrophobic porous hollow fiber membrane is fixed to a resin container, a predetermined pressure (0.03 MPa in this embodiment) is applied to the outside of the hollow fiber by air, and the volume of air permeated inside the hollow fiber is 90 mL. After measuring the time required to become a soap film flow meter and calculating the air permeation amount per second, the following formula:

Was used to determine the air permeability coefficient.

The hydrophobic porous hollow fiber membrane used in this example is made of polyethylene. According to the above measurement method, the outer diameter is 1.25 mm, the inner diameter is 0.68 mm, the film thickness is 285 μm, the porosity is 81%, and the average pore diameter is 0.19 μm. The inner surface opening ratio was 21%, the outer surface opening ratio was 21%, and the air permeability coefficient was 7.1 × 10 ⁻⁷ m ³ / (m ² · sec · Pa).

(2) Implementation of membrane distillation Evaporation module (evaporation part) containing 33 hydrophobic porous hollow fiber membranes in a polysulfone case with an inner diameter of 20 mm, and 20 stainless steel tubes with an inner diameter of 1 mm and an outer diameter of 2 mm as an evaporation part The collection module (collection unit) housed in a case of the same type as used in Fig. 2 was connected as shown in Fig. 2B. At this time, the shortest distance between the outer surface of the hydrophobic porous hollow fiber membrane in the evaporation portion and the outer surface of the stainless steel tube in the recovery portion was set to 30 mm.
The outlet of the recovery unit was connected to a water sampling container by piping, and the gas phase part of the water sampling container was connected to a decompression device via a pressure regulator to adjust the pressure in the system.
5. The temperature adjusted to 65 ° C. in the hollow lumen of the hydrophobic porous hollow fiber membrane in the evaporation section. The oil field-associated water filtrate obtained in 1 was circulated at a flow rate of 600 mL / min. Cooling water at 30 ° C. was circulated at a flow rate of 1,000 mL / min in the lumen of the stainless steel tube of the recovery unit. And the pressure in a module system was adjusted to 10 kPa, and membrane distillation was performed.

(3) Measurement (conductivity of purified water)
The conductivity of purified water obtained by membrane distillation was measured using a conductivity measuring instrument desktop type, model “DS-52” manufactured by Horiba, Ltd.
(Leakage)
When the conductivity exceeded 3% (0.81 mS / cm) of the oil field-associated water filtrate, it was regarded as leakage, and the time from the start of membrane distillation to the leakage was regarded as the leakage time.
(Water production)
The amount of membrane distilled water collected in the water sampling container was measured with an electronic balance, and the amount of water collected from the start of membrane distillation to the leakage was regarded as the amount of water produced.

(4) Results FIG. 5 shows the change over time in the conductivity of purified water in this example.
The conductivity of purified water during 44 hours after the start of the membrane distillation changed in the range of about 0.14 to 0.40 mS / cm. After 44 hours, the conductivity increased to 1.12 mS / cm, and leakage was confirmed. The leakage time was 44 hours, and the amount of water produced was 4.5 kg.

(Comparative Example 1)
In Example 1 above, membrane distillation was performed in the same manner as in Example 1 except that a filter composed of a stainless mesh having a mesh number of 150 was used instead of the oil-water separation filter. FIG. 5 shows the change over time in the conductivity of the purified water obtained.
The conductivity of purified water during the 16 hours after the start of membrane distillation changed in the range of approximately 0.08 to 0.15 mS / cm. After 16 hours, the conductivity increased to 2.41 mS / cm, and liquid leakage was confirmed. The leakage time was 16 hours, and the amount of water produced was 1.5 kg.

(Reference Example 1)
Membrane distillation having the structure shown in FIG. 2B was performed in the same manner as in Example 1 except that an evaporation module in which 66 hydrophobic porous hollow fiber membranes same as those in Example 1 were housed in a polysulfone case having an inner diameter of 20 mm was used. Using an apparatus, membrane distillation of simulated coal bed methane wastewater having the composition shown in Table 1 was performed.
After starting the membrane distillation, the conductivity of the purified water during 170 hours changed in the range of about 0.8 to 2.0 μS / cm. No liquid leakage was confirmed, and the amount of water produced for 170 hours was 37.0 kg.

  This system can be used, for example, for wastewater treatment in offshore oil and gas fields; treatment of associated water produced with the aging of conventional oil and gas fields; non-conventional oil (eg, shale oil, oil sands, etc.) In addition, it can be suitably used for applications such as securing process water and associated water treatment during mining of unconventional gas (eg, shale gas, coal bed methane, etc.); treatment of factory wastewater; oil purification, etc. .

1 Hydrophobic porous membrane 2 Cooling body

Claims (15)

at least,
A filtration unit for filtering the liquid to be treated with an oil-water separation filter having a nonwoven fabric with a wetting tension of 25.4 mN / cm or less;
A distillation section for distilling the filtrate obtained in the filtration section;
The water purifier characterized by having.   The water purifier according to claim 1, wherein the nonwoven fabric is a nonwoven fabric subjected to a hydrophilic treatment. The hydrophilization treatment,
Sulfonation treatment and one or more treatments selected from the group consisting of grafting treatment with one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, polymethylpyrrolidinone, polyalkylene glycol, and polyether The water purifier according to claim 2, wherein   The water purifier as described in any one of Claims 1-3 whose hexadecane contact angle after water impregnating the said nonwoven fabric is 5 degrees or more. Of the nonwoven fabric,
The basis weight is 1 to 500 g / m ² .
The fiber thickness is 0.1-50 μm,
The pore size is 0.1-120 μm and the thickness is 0.1-5 μm,
The water purifier as described in any one of Claims 1-4. The filtration unit is
The liquid to be treated and the filtrate are adjacent via the oil / water separation filter,
The water purifier as described in any one of Claims 1-5 which has a function which filters the to-be-processed liquid, maintaining the liquid level of the to-be-processed liquid higher than the liquid level of the said filtrate.   The water purifier according to any one of claims 1 to 6, wherein the distillation unit is a membrane distillation system. The membrane distillation system comprises:
A filtrate evaporating part in which the liquid phase part 1 where the filtrate is present and the gas phase part 1 are adjacent to each other via a hydrophobic porous membrane;
A liquid phase part 2 through which cooling water flows, a gas phase part 2 adjacent to each other via a cooling body, and a gas phase part 3 connecting the gas phase part 1 and the gas phase part 2 are connected.
With
The water purifier according to claim 7, wherein the gas phase parts 1 to 3 have a pressure equal to or higher than 1 kPa and equal to or lower than a saturated vapor pressure of water at a filtrate temperature.   The water purifier according to claim 8, wherein the gas phase part 1 and the hydrophobic porous membrane are immersed in the liquid phase part 1.   The water purifier according to claim 8 or 9, wherein a shortest distance between the hydrophobic porous membrane and the cooling body is 10 mm or more.   The water purifier as described in any one of Claims 8-10 whose said filtrate temperature is 50 degreeC or more.   The hydrophobic hydrophobic membrane includes at least one resin selected from the group consisting of polysulfone, polyethersulfone, polyethylene, polypropylene, polyvinylidene fluoride, and polytetrafluoroethylene. The water purifier according to item.   The water purifier according to any one of claims 8 to 12, wherein the hydrophobic porous membrane is a hollow fiber membrane. The hydrophobic porous membrane has a surface porosity of the membrane surface in contact with the filtrate of 20% or more and an air permeability coefficient of 7.0 × 10 ⁻⁷ m ³ / m ² · sec · Pa or more. The water purifier as described in any one of Claims 8-13 which exists.   The water purification apparatus according to any one of claims 8 to 14, wherein the hydrophobic porous membrane has an average pore diameter of 0.15 µm or more and a porosity of 60% or more.

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