JP3759976B2 - Removal method of dissolved organic halons in water - Google Patents

Description

表１に示す様に、実施例１のモジュールは比較例１のものと比較して、クロロホルムを効率的に除去できた。また、換気量を、水処理量の１０倍〜２００倍とした場合に特に優れた結果が得られた。
【００４１】
【発明の効果】
以上説明した様に、本発明の水中溶存有機ハロン除去用中空糸膜モジュールは、中空糸膜がクロスワインディングされているので、中空糸膜長が長くてもたるまない。したがって、モジュール作製時の糸のたるみ等による糸切れや糸のからみ等が発生せず、欠陥が生じ難いモジュールである。また、中空糸外表面を流れる流体のチャネリングも生じ難く、有機ハロンの除去性能も高く、更にはモジュール内の中空糸膜は安定しているので、運搬時や使用時等に糸の擦れが少なく問題が生じ難い。しかも、本発明の中空糸膜モジュールは、紡糸や紡績等で一般的に用いられるワインダーを利用することによって簡易に製造できる。
【００４２】
また、本発明の水中溶存有機ハロン除去方法は、本発明の中空糸膜モジュールを用いるので簡易かつ良好に有機ハロンを除去でき、また同時に換気量を特定範囲にすることによって、効率的に実施でき、装置の小型化も達成できる。
【図面の簡単な説明】
【図１】本発明の水中溶存有機ハロン除去中空糸膜モジュールの一態様を示す模式図である。
【図２】図１のモジュールに用いた中空糸膜巻体の模式的部分断面図である。
【図３】複合中空糸膜の模式図である。
【符号の説明】
１ 容器
２ 外気を吸い込む吸気口
３ 中空糸膜
４ 中空糸膜巻体
５ ポッティング剤
６ 多孔状中空芯部材
７ 水溶液の導入口
８ 水溶液の導出口
９ 脱有機ハロンガスおよび水蒸気口
１０、１１ キャップ
３０ 多層複合中空糸膜
３１ 均質膜
３２ 多孔質膜[0001]
[Industrial application fields]
The present invention relates to how you remove the organic Halon dissolved in the water using a hollow fiber membrane module.
[0002]
[Prior art]
Most of the modules using conventional hollow fiber membranes are obtained by aligning hollow fibers in a straight line and supporting and fixing both ends with a potting agent. Further, a method for producing a module by processing a hollow fiber membrane into a sheet-like material such as suede knitting and laminating or winding it is disclosed in JP-A-58-155862, JP-A-61-18143, JP-A-63. -236502, JP-A-2-102660, JP-A 61-125183, JP-A 62-57965, and the like.
[0003]
As a conventional method for removing dissolved gas, a method for reducing the pressure of a container containing a solution and a method and an apparatus for removing dissolved gas by chemical treatment are known. However, such an apparatus has problems that it is difficult to completely remove dissolved gas and that the removal time is long. From this point, recently, a dissolved gas removing device using a hydrophobic porous membrane has been proposed (Japanese Patent Laid-Open No. 62-42707). Also known is a method for removing dissolved gas using a composite hollow fiber membrane having a three-layer structure in which a homogeneous layer is sandwiched between porous layers from both sides (Japanese Utility Model Laid-Open No. 3-7908, Japanese Patent Laid-Open No. 3-169303). Issue gazette).
[0004]
[Problems to be solved by the invention]
In the conventional hollow fiber membrane module, since the hollow fiber membranes arranged in the container are linearly arranged and only the both ends of the hollow fiber membranes are fixed with a potting agent, the length of the hollow fiber membranes becomes long. It is easy to sag, which makes it difficult to manufacture and also tends to cause defects in the hollow fiber membrane. As a conventional technique for preventing sagging, there is, for example, a method in which a converging plate is arranged in a container and a hollow fiber membrane is fixed to some extent through holes formed in the converging plate. However, such a module is difficult to manufacture, and further, a fundamental problem such as a defect caused by rubbing between the focusing plate and the hollow fiber membrane is not a fundamental solution. As another conventional technique, there is a method of producing a module by converging a hollow fiber membrane with a pipe having an opening on a side surface. However, it is difficult to insert the hollow fiber membrane into the pipe without damaging the hollow fiber membrane, and not only the filling rate is lowered, but also channeling is generated in the fluid flowing on the outer surface of the hollow fiber membrane.
[0005]
Further, in the conventional hollow fiber membrane module in which the hollow fiber membranes are linearly arranged and filled in the container, the hollow fiber membranes are in linear contact with each other, so there is a problem that the contact portion is large and the membrane surface cannot be used effectively. . In order to improve the membrane surface utilization rate, the filling rate of the hollow fiber membranes may be reduced to reduce the contact portion between the hollow fiber membranes, but in this case, the container becomes large. On the other hand, as a conventional technique, there is also a hollow fiber membrane module that uses a sheet-like material such as a knitted fabric of a hollow fiber membrane, and that uses a membrane surface effectively by forming a fixed space between the hollow fiber membranes with warp yarns that are knitting yarn is there. However, it is difficult to produce a sheet-like material without damaging the hollow fiber with a loom or warp, and since the warp yarn is arranged between the hollow fiber membranes, the spacing between the hollow fiber membranes is widened and the filling rate is reduced. End up.
[0006]
Further, in a conventional hollow fiber membrane module using a hollow fiber membrane processed into a sheet shape, the hollow fiber membrane is made into a sheet-like product by processing such as cutting or knitting, and is wound or laminated. Therefore, the manufacturing process is complicated and work efficiency is not good.
[0007]
In order to remove water-dissolved organic halons using the hollow fiber membrane module, the organic halon gas partial pressure on the gas side of the hollow fiber membrane must be equal to or lower than the organic halon gas partial pressure in water. As a method for this purpose, there are a decompression method in which the pressure is reduced using a vacuum pump, and a ventilation method in which a gas not containing an organic halon gas such as an inert gas is sucked or supplied. However, in the depressurization method, a substance having a strong interaction with water such as organic halon cannot be effectively removed at a depressurization degree equal to or higher than the saturated water vapor pressure. Also, in the ventilation method, if the ventilation volume is low, sufficient removal of dissolved organic halons in water will not be exhibited, and if ventilation means such as an intake (or air supply) pump with a ventilation capacity more than necessary is used, the removal efficiency will increase. This is wasteful and further increases the size of the apparatus.
[0008]
An object of the present invention, does not occur slack long hollow fiber membrane length, membrane surface utilization of the hollow fiber membrane is high, and then dissolved in water by means of Soraitomaku module within that can be easily manufactured It is to provide a method for removing organic halons .
[0009]
Another object of the present invention is to provide an efficient and simple method for removing dissolved organic halons in water.
[0011]
[Means for Solving the Problems]
The method for removing dissolved organic halons in water according to the present invention comprises a hollow fiber wound body obtained by cross-winding a hollow fiber membrane on a porous hollow core member, a space communicating with the hollow portion of the hollow fiber membrane, and the hollow fiber membrane And a space communicating with the hollow portion of the hollow fiber membrane using a hollow fiber membrane module in which the hollow fiber membrane is isolated from the outer surface of the porous hollow core member and a space communicating with the hollow portion of the porous hollow core member. The other space at a flow rate of 50 to 200 times the amount of treated water introduced into one of the outer surface of the hollow fiber membrane and the space communicating with the hollow portion of the porous hollow core member It is characterized by ventilating the gas.
[0012]
The hollow fiber membrane module of the present invention has a hollow fiber membrane wound body obtained by cross-winding one or a plurality of hollow fiber membranes on a porous hollow core member. Here, the cross-winding means that the hollow fiber membranes are laminated in layers, and each layer is regularly laminated so that the axial direction of the adjacent layer and the hollow fiber membrane intersect.
[0013]
Cross-winding hollow fiber membranes do not sag at the time of module production, etc., compared to conventional linearly arranged hollow fiber membranes. Does not occur. In addition, since the hollow fiber membranes are uniformly arranged as compared with the linear arrangement type hollow fiber membranes obtained by the conventional wiping method, channeling of the fluid flowing on the outer surface of the hollow fibers hardly occurs. Furthermore, since the hollow fiber membrane is arranged in a spiral shape, the yarn length can be further increased and the removal performance can be improved. Furthermore, since the hollow fiber membrane is in a state of being regularly entangled in a spiral shape, the hollow fiber membrane in the module is stable, there is little thread rubbing during transportation or use, and thread breakage or the like occurs. Difficult to cause leak problems.
[0014]
In order to cross-wind the hollow fiber membrane, a winder generally used in spinning or spinning may be used. In winding, the tension and the winding speed may be appropriately set so that the hollow fiber membrane is not crushed. This hollow fiber membrane wound body can be manufactured by simply winding the hollow fiber membrane around a porous hollow core member with a winder, and can be stored in a container as it is and processed as a module. That is, the hollow fiber module of the present invention can be easily and efficiently manufactured as compared with a conventional module manufacturing method that requires processing such as picking or stacking.
[0015]
As the hollow fiber membrane in the present invention, a hydrophobic porous membrane having a pore diameter of 0.05 μm or less can be used. However, when used for a long time, water vapor leaks, and as a result, water may leak from the porous membrane. There is sex.
[0016]
Therefore, as the hollow fiber membrane in the present invention, it is desirable to use a composite hollow fiber membrane having a three-layer membrane structure in which the homogeneous layer 31 is sandwiched between the porous layers 32 from both sides as illustrated in FIG. The film thickness of the homogeneous layer 31 is usually 8 μm or less, and the porous layer 32 also has a reinforcing function.
[0017]
The multilayer composite hollow fiber membrane 30 preferably has a water vapor transmission rate of 3 × 10 ⁻³ (cm ³ (STP) / cm ² · sec · cmHg) or more, and the chloroform transmission rate is 1 × 10 ⁻³ (cm ³ (STP) / cm ² · sec · cmHg) or more. If the water vapor transmission rate is too low or the chloroform transmission rate is too low, the rate at which organic halons dissolved in water pass through the composite hollow fiber membrane is too slow, and organic substances tend not to be efficiently removed.
[0018]
Examples of the material for forming the porous layer 32 include polyolefins such as polyethylene, polypropylene, poly-3-methylbutene-1, and poly-4-methylpentene-1; fluorine-based polymers such as vinylidene fluoride and polytetrafluoroethylene; polysulfone; Various polymers such as polyetheretherketone; polyetherketone can be used. Polyolefin, which is a crystalline polymer, is preferred in that it can be easily porous.
[0019]
Examples of the material used for the homogeneous layer 31 include segmented polyurethane; silicon-based polymer; polyolefin such as low-density polyethylene and poly-4-methylpentene-1; polyacrylamide and the like. High polymer is preferred.
[0020]
Such a multilayer composite hollow fiber membrane 30 is obtained by, for example, a method described in Japanese Patent Publication No. 3-44811 or the like, that is, a polymer and a porous layer 32 that form a homogeneous layer 31 using a multi-cylindrical spinning nozzle. The polymer to be formed can be alternately arranged and melt-spun, and then stretched under the condition that only the porous layer 32 is made porous without making the homogeneous layer 31 porous. Such a multilayer composite hollow fiber membrane can effectively remove organic substances dissolved in water, especially volatile organic substances having a high gas phase concentration in gas / liquid equilibrium. Among volatile organic substances, particularly highly polar organic halons are particularly useful in the present invention because they have high affinity with the polymer material usually used in the homogeneous layer 31 and can be efficiently removed.
[0021]
Further, the hollow fiber membrane module of the present invention is preferably one of a space communicating with the hollow portion of the hollow fiber membrane and a space communicating with the outer surface of the hollow fiber membrane and the hollow portion of the porous hollow core member. One of the spaces has an inlet for introducing water and an outlet for discharging water, and an exhaust port and an inlet for ventilating gas in the other space.
[0022]
The method for removing dissolved organic halons in water of the present invention uses the hollow fiber membrane module of the present invention described above, the space communicating with the hollow part of the hollow fiber membrane, the outer surface of the hollow fiber membrane, and the porous hollow core. The gas in the other space is ventilated at a flow rate 50 to 200 times the amount of treated water introduced into any one of the spaces communicating with the hollow portion of the member. According to the method of the present invention, since the hollow fiber membrane module of the present invention is used, organic halons can be removed easily and satisfactorily. An intake pump or a blower having an exhaust capability that exhibits the removal performance can be selected, and thereby a small device can be designed without waste.
[0023]
When the ventilation rate is 5 times or less of the water treatment amount, the organic halon gas and water vapor that permeate the hollow fiber membrane are not exhausted sufficiently and the organic halon gas remains in the vicinity of the gas phase side. A difference in organic halon gas partial pressure from the gas phase does not occur, and sufficient organic halon removing performance cannot be exhibited. Insufficient water vapor exhaust accumulates in the gas phase as condensed water, reducing the effective membrane area, adversely affecting removal performance, and at the same time, causing dangerous bacteria to grow in the condensed water and scatter in the exhaust gas There is sex. On the other hand, when ventilating at 200 times or more of the amount of water to be treated, there is a need to use a considerably large air supply (exhaust) device, which causes problems such as an increase in size and noise of the device, and more than necessary. If the ventilation is performed for a long time, dust floating in the air adheres to the surface of the hollow fiber membrane and causes a reduction in the effective membrane area.
[0024]
Examples of ventilation means for ventilating at a flow rate 50 to 200 times the amount of water treated include a blower or an intake blower. Moreover, you may use the vacuum pump with a small and strong suction power. The types of vacuum pumps include an oil rotary type, a water ring type, a diaphragm type, etc. Among them, a small diaphragm type vacuum pump that is easy to handle and small is preferable.
[0025]
Hereinafter, the hollow fiber membrane module of the present invention will be described in more detail with reference to FIGS. 1 and 2. FIG. 1 is a schematic view showing an embodiment of the hollow fiber membrane module for removing dissolved organic halons in water of the present invention. FIG. 2 is a schematic partial cross-sectional view of the hollow fiber membrane wound body used in the module of FIG.
[0026]
In the hollow fiber membrane module shown in FIG. 1, a hollow fiber membrane wound body 4 is vertically arranged inside the container 1, and both ends thereof are supported and fixed by a potting agent 5. As shown in FIG. 2, the hollow fiber membrane wound body 4 is formed by cross-winding one or a plurality of hollow fiber membranes 3 on a porous hollow core member 6. The porous hollow core member 6 is provided with a large number of holes on the side surface of a pipe-shaped hollow member, for example, and allows fluid to pass therethrough.
[0027]
An inlet 7 is provided at the upper part of the module, and an outlet 8 is provided at the lower part. The introduction port 7 is an opening for introducing water containing dissolved organic halons (water before treatment) into the module. The outlet 8 is an opening through which water (water after treatment) after removing dissolved organic halons is led out of the module. In the following description, water before and after the above treatment is generically referred to as an aqueous solution.
[0028]
A plurality of air inlets 2 are provided on the peripheral wall of the container 1. The intake port 2 is an opening for sucking outside air into the module. In the upper part of the module, the porous hollow core member 6 is connected to a deorganized halon gas and water vapor port 9 that penetrates a cap 10 having an upper potting agent 5 and an introduction port 7. In the lower part of the module, the porous hollow core member 6 is provided with a cap 11 having an upper potting agent 5 and an outlet port 8.
[0029]
In the module of FIG. 1, the spaces communicating with the hollow portions of the multiple hollow fiber membranes 3, 3,... 3 are the introduction port 7, spaces A and B, the hollow portion in the hollow fiber membrane 3, the space C, It is a space that communicates in the order of the outlet 8, and an aqueous solution to be treated flows into this space. On the other hand, the space communicating with the outer surface of the multiple hollow fiber membranes 3, 3,... 3 and the hollow portion of the porous hollow core member 6 includes the air inlet 2, the outside of the hollow fiber membrane wound body 4, and the empty yarn. The outer surface of the membrane 3, the hole of the porous hollow core member 6, the hollow portion of the porous hollow core member 6, the deorganized halon gas, and the water vapor port 9 communicate with each other in this order. The two spaces are completely isolated at portions other than the hollow fiber membrane as a boundary membrane, and it is organic halon gas and water vapor that pass through the hollow fiber membrane that can move through both spaces.
[0030]
That is, the aqueous solution is introduced from the introduction port 7 and introduced from the introduction port 7 into the spaces A and B (A and B are spaces communicating with each other) constituted by the end face of the potting agent 5 and the cap 10, and the hollow fiber membrane. The organic halon dissolved in water passes through the hollow portion in 3 and moves to the space outside the hollow fiber membrane when passing through the hollow portion. Then, the aqueous solution from which the organic halon has been removed reaches the space C composed of the potting agent 5 and the cap 11 and is led out from the outlet 8.
[0031]
At the same time, the space outside the hollow fiber membrane 3 is ventilated in order to make the organic halon gas partial pressure outside the hollow fiber membrane 3 lower than the organic halon gas partial pressure in water. In this ventilation, outside air is sucked from the air inlet 2, and the outer surface of the hollow fiber membrane 3, the hole of the porous hollow core member 6, the hollow portion of the porous hollow core member 6, and the removal from the outside of the hollow fiber membrane wound body 4. The organic halon gas and the water vapor port 9 are vented and exhausted in this order. When the outside air passes through the outer surface of the hollow fiber membrane 3, the organic halon removed from the water moves together with the water vapor, and the outside air containing the organic halon and the water vapor is exhausted from the de-organic halo gas and the water vapor port 9. The
[0032]
In the module of FIG. 1, the intake port 4 (or the deorganic organic gas and water vapor port 9) for sucking outside air is used as the aqueous solution introduction port (or aqueous solution outlet), and the aqueous solution inlet 7 (or aqueous solution outlet 8). ) Can be used as an intake port (or a deorganic organic gas and water vapor port) for sucking outside air.
[0033]
【Example】
Hereinafter, the present invention will be described in more detail based on examples.
[0034]
<Production Example 1 of Hollow Fiber Membrane>
High-density polyethylene (trade name Hizex2200j, manufactured by Mitsui Petrochemical Co., Ltd.) is supplied to the intermediate layer as a polymer material to be supplied to the inner and outer layers of the nozzle for manufacturing hollow fiber membranes having three outlets arranged concentrically. Segmented polyurethane (manufactured by Thermedics Ink., Trade name Tecoflex EG80A) was used as a polymer material to be spun at a discharge temperature of 165 ° C. and a winding speed of 180 m / min. The obtained hollow fiber undrawn yarn was annealed at 100 ° C. for 1 hour. Next, the annealed yarn was stretched 80% at room temperature, and subsequently heat-stretched in a heating furnace heated to 105 ° C. until the thermal stretch ratio became 130%, to obtain a composite hollow fiber membrane.
[0035]
The obtained composite hollow fiber membrane has a three-layer structure as shown in FIG. 3 and has an inner diameter of 200 μm. From the innermost layer, a porous layer 32 having a thickness of 25 μm, a homogeneous layer 31 having a thickness of 1 μm, and a thickness of 30 μm, respectively. The porous layer 32 was arranged concentrically. When the surface of the porous layer 32 was observed with a scanning electron microscope, it was confirmed that slit-shaped holes having a width of 0.06 to 0.09 μm and a length of 0.1 to 0.5 μm were formed. . The composite hollow fiber membrane has a water vapor transmission rate of 8 × 10 ⁻³ (cm ³ (STP) / cm ² · sec · cmHg), and a chloroform transmission rate of 2 × 10 ⁻³ (cm ³ (STP) / cm ² · sec · cmHg).
[0036]
<Example 1>
Using the composite hollow fiber membrane obtained in Production Example 1, the hollow fiber membrane module shown in FIG. 1 was produced.
[0037]
The water treatment amount was 1.0 liter / minute or 2.0 liter / minute, the ventilation amount was changed to 1 to 400 times the water treatment amount, and an aqueous solution containing 50 ppb chloroform as water-dissolved organic halon was treated. The module membrane area was 3 m ² . The concentration of chloroform contained in the aqueous solution after treatment was measured, and the removal rate of chloroform was calculated according to the following formula.
[0038]
Chloroform removal rate (%) = {1- (Ci-Co) / Ci} × 100
Ci: Chloroform concentration contained in the aqueous solution entering the module Co: Chloroform concentration contained in the aqueous solution exiting from the module The evaluation results are shown in Table 1 below.
[0039]
<Comparative Example 1>
A module similar to that of Example 1 was produced except that the composite hollow fiber membrane obtained in Production Example 1 was not wound around the porous hollow core member 6 and was linearly arranged in the vertical direction around the core member 6. Using this module, the removal rate of chloroform was calculated in the same manner as in Example 1. The results are shown in Table 1 below.
[0040]
[Table 1]
Table 1

As shown in Table 1, the module of Example 1 was able to remove chloroform more efficiently than that of Comparative Example 1. In addition, particularly excellent results were obtained when the ventilation amount was 10 to 200 times the water treatment amount.
[0041]
【The invention's effect】
As described above, in the hollow fiber membrane module for removing dissolved organic halons in water of the present invention, since the hollow fiber membrane is cross-winded, the hollow fiber membrane length is long. Therefore, the module does not easily cause defects due to no thread breakage or thread entanglement due to slack of the thread during module manufacture. In addition, channeling of the fluid flowing on the outer surface of the hollow fiber is unlikely to occur, the organic halon removal performance is high, and the hollow fiber membrane in the module is stable, so there is little thread rubbing during transportation or use. Problems are unlikely to occur. And the hollow fiber membrane module of this invention can be easily manufactured by utilizing the winder generally used by spinning, spinning, etc.
[0042]
In addition, the method for removing dissolved organic halons in water of the present invention can be easily and satisfactorily removed organic halons using the hollow fiber membrane module of the present invention, and at the same time can be efficiently carried out by setting the ventilation rate to a specific range. Also, downsizing of the device can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing one embodiment of a hollow fiber membrane module for removing dissolved organic halons in water of the present invention.
FIG. 2 is a schematic partial cross-sectional view of a hollow fiber membrane wound body used in the module of FIG.
FIG. 3 is a schematic view of a composite hollow fiber membrane.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Container 2 Air intake port 3 which sucks in external air Hollow fiber membrane 4 Hollow fiber membrane wound body 5 Potting agent 6 Porous hollow core member 7 Aqueous solution introduction port 8 Aqueous solution discharge port 9 Deorganic organic halon gas and water vapor ports 10 and 11 Cap 30 Multi-layer Composite hollow fiber membrane 31 Homogeneous membrane 32 Porous membrane

Claims (2)

A hollow fiber wound body obtained by cross-winding a hollow fiber membrane on a porous hollow core member, a space communicating with a hollow portion of the hollow fiber membrane, an outer surface of the hollow fiber membrane, and the porous hollow core member Using a hollow fiber membrane module in which a space communicating with a hollow portion is isolated using the hollow fiber membrane as a boundary membrane, a space communicating with a hollow portion of the hollow fiber membrane, an outer surface of the hollow fiber membrane, and the porous shape Underwater characterized in that the gas in the other space is ventilated at a flow rate 50 to 200 times the amount of treated water introduced into any one of the spaces communicating with the hollow portion of the hollow core member. Dissolved organic halon removal method. The hollow fiber membrane is a composite hollow fiber membrane having a three-layer membrane structure in which a homogeneous layer is sandwiched between porous layers from both sides, and a water vapor transmission rate of a material constituting the homogeneous layer is 3 × 10 ⁻³ (cm ^3). (STP) / cm and a ² · sec · cmHg) or more, chloroform permeation rate ^{1 × 10 -3 (cm 3 (} STP) / cm 2 · sec · cmHg) or the water dissolved organic halon according to claim 1, wherein Removal method.

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