JP2725311B2 - Hollow fiber membrane type gas-liquid contactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention brings a liquid and a gas into contact with each other through a membrane, and dissolves the gas into the liquid or releases the gas contained in the liquid, or dissolves and releases these gases. And a gas-liquid contact device for the purpose of simultaneously performing the above steps.

The present invention is, for example, the supply of oxygen in the cultivation of microorganisms such as yeast and aerobic bacteria in the pharmaceutical and food industries, the supply of oxygen in the treatment of wastewater by aerobic bacteria, the air oxidation in the chemical industry, the pharmaceutical industry, Ozone oxidation, fish farming, oxygen supply in transporting fish, oxygen supply to culture medium in hydroponics, for facial beauty,
Production of high oxygen water for health drinks, also於Ru SOx as applications to remove, for example, in the waste gas purification by dissolving one or more components in the gas to liquid, NOx, removal of such H ₂ S, from the fermentation methane CO ₂ removal, also was deoxygenated of feed to the degassing applications as for example boiler feed water, reverse osmosis membranes of the liquid, deoxygenation of semiconductor cleaning ultrapure water, the rust of piping and cooling device intended , water and sea water deoxygenation, decarbonation, CO ₂ removal from microbial broth, removal of the organic solvent in the wastewater, also a於Ru O ₂ supplied as applications performing dissolution and release at the same time, for example, microorganisms of the gaseous CO It can be used in industrial fields such as ₂ removal.

[Prior art] Conventional silicon rubber tubes (Japanese Patent Publication No. 58-20261), polypropylene porous hollow fibers (Japanese Patent Application Laid-Open No. 55-1816), polytetrafluoride Ethylene (PTFE) porous tube, polysulfone porous hollow fiber (H.YASUDA, etc .; Journal of Applied Polymer Sc
inece, 16 , 595-601 (1972)) and the like. However, silicone rubber tubes have a low gas permeation rate,
Since it is difficult to produce a thin hollow fiber, the apparatus has a drawback that the apparatus is bulky, the pressure resistance is small (especially when the outside of the hollow fiber is pressurized), and the increase in the permeation speed due to pressurization cannot be measured. Although porous membranes are superior to silicon rubber tubes in gas permeation rate, they tend to generate bubbles and are also limited in pressurization. Blockage, drastically decreasing gas permeation rate,
For the same reason, it has a disadvantage that it cannot be used for a system containing a surfactant or an organic solvent system.

On the other hand, in terms of the structure of the gas-liquid contacting device, the so-called internal perfusion type, in which a liquid flows inside the hollow fiber, is the mainstream from the viewpoint of ease of manufacturing the device. However, in the case of the internal perfusion type, the liquid-side membrane resistance increases, and even if a substance having a high gas permeation rate is used for the membrane, the gas exchange rate of the apparatus remains at a low level, and the required membrane area increases, and the apparatus becomes large. It had to be expensive. The pressure loss on the liquid side also increases,
This has led to an increase in the size of the pump and an increase in operating power costs.

In addition, the external perfusion type is expected to reduce the pressure loss, increase the gas exchange rate due to the effect of stirring the liquid, and reduce the required membrane area. Since the liquid drifts due to unevenness and the like, and the substantial contact area between the liquid and the film is reduced, the required film area is also increased.

Further, in applications for removing gas from a fluid, for example, in a hollow fiber membrane type gas-liquid contacting device used for deoxidation of water, a type in which a fluid from which gas is to be removed flows to the outside of the hollow fiber (gas removal is required) In the case of an external perfusion type when the fluid is a liquid, it is difficult to remove the residual gas amount to a certain level or less, and a type in which the amount of gas remaining outside the hollow fiber is not practically used.

[Problems to be Solved by the Invention] The present inventors have solved the above-mentioned drawbacks, and have a compact and widely applicable device, particularly a membrane type which exhibits high performance even in removing gas from a fluid. In order to realize the gas-liquid contact device, the present inventors have made intensive studies on both the structure of the diaphragm and the structure of the gas-liquid contact device, and have reached the present invention.

[Means for Solving the Problems] That is, the gist of the present invention is to provide a gas-liquid contacting device for bringing a liquid and a gas into contact with each other via a gas exchange membrane and moving or mutually exchanging the gas through the membrane. If the membrane is poly-
An apparent oxygen permeability coefficient P ′ at 25 ° C. made of a material having (4-methylpentene-1) as a substantially main component.
(O ₂ ) is 4 × 10 ⁻⁹ [cm ³ (STP) / cm ² , sec, cmHg] or more, and the separation coefficient α (O ₂ /
N ₂ ) is a hollow fiber membrane of 1.1 or more, wherein the hollow fiber is incorporated in a case in a state of a superposed body or a bundle of sheet-like materials organized by hollow fibers or other yarns. And a hollow fiber membrane type gas-liquid contact device.

The hollow fiber membrane type gas-liquid contact device of the present invention is used for degassing from a liquid, which is an external perfusion type in which liquid flows in contact with the outside of the hollow fiber membrane and gas is permeated to the inside of the hollow fiber membrane. In addition, there is an internal perfusion type in which a gas mixture flows in contact with the outside of the hollow fiber membrane, and a specific type of gas is separated and transferred to a liquid flowing inside the hollow fiber membrane. Is also obtained by braiding hollow fibers arranged in parallel with other yarns which are substantially perpendicular to the hollow fibers in a cord shape.

The present invention firstly relates to a gas exchange membrane as to its main parts.

Gas exchange membranes used in this type of apparatus can be classified according to their cross-sectional structure, when the pores communicate with the front and back of the membrane (communication pore membrane) and when the pores do not communicate (non-communication pore membrane). Are roughly divided into Conventionally used polypropylene and PTFE
Are porous membranes. Non-communicating pore membranes can be classified into membranes that have no pores (homogeneous membranes, silicone rubber tubes belong to them) and membranes that have pores but do not communicate on the front and back (asymmetric membranes) . And
The asymmetric membrane includes a heterogeneous membrane in which a porous portion and a non-porous portion are made of the same material, and a composite membrane in which both portions are made of different materials.

In order to withstand long-term use and to be able to be used stably even in a liquid containing a surfactant or the like, the non-communication pore membrane meets the purpose. However, the gas is permeated by the dissolution-diffusion mechanism in the non-communication pore membrane, so that the permeation speed is usually inferior to that of the porous membrane. That is, it is generally known that the rate of dissolution of gas into water through a membrane is as follows.
Porous membrane> composite membrane> non-porous homogeneous membrane.

Although the hollow fiber membrane used in the present invention contains fine voids (voids) inside the membrane wall, pores are substantially formed on at least one surface of the membrane, that is, one or both of the outer surface and the inner surface of the hollow fiber. It has a so-called heterogeneous film structure that is not open. With this structure, a decrease in permeation performance due to intrusion of the liquid into the pores is prevented.

Conventionally, such a heterogeneous membrane or a composite membrane is inferior to a porous membrane having a communication hole in terms of a gas permeation rate in a gas-liquid system, that is, a gas dissolution rate in a liquid or a gas release rate from a liquid. .
However, the present inventors have found that when the membrane is a membrane composed of poly (4-methylpentene-1) having characteristic gas permeation characteristics, the gas-liquid gas exchange rate is specifically increased. Was. In the case of a non-communicating pore membrane, gas permeates through a polymer compound by dissolution and diffusion, and thus the non-communicating pore membrane has a higher permeation rate than a communicating pore membrane in which gas moves and permeates by volume flow. Is surprising. It is also noteworthy that the membrane used in the present invention exhibits a higher permeation rate in a gas-liquid system than a so-called composite membrane in which a non-porous layer is formed on a polypropylene or other porous membrane.

The structure of the film, that is, the existence of voids inside the film wall and the opening state of pores on the film surface can be observed to some extent by a scanning electron microscope (SEM). It is not appropriate to use SEM observation to specify the structure and performance of the film because of its small size. The amount of voids inside the membrane wall and the extent of the presence of pores (pinholes) communicating between the front and back of the membrane can be clearly determined by measuring the apparent gas permeation coefficient and separation coefficient of oxygen and nitrogen. That is, when there are voids or pores inside the membrane, the substantial thickness through which the gas permeates by dissolution and diffusion decreases, and the apparent oxygen permeability coefficient P ′ (O ₂ ) calculated by the following equation becomes , Material oxygen permeability coefficient P
(O ₂ ) (= 1.6 × 10 ^-9 [cm ³ (STP) cm / cm ² · sec · cmH
g]). Here, the apparent transmission coefficient is a transmission coefficient calculated using the apparent film thickness including a void as the film thickness. The measurement is performed according to ASTM D1434. The apparent film thickness can be measured by observing the cross section of the hollow fiber with an optical microscope.

Where V: volume of permeated gas [cm ³ (STP)] l: apparent film thickness [cm] A: film area [cm ² ] t: time required for permeation [sec] Δp: pressure difference between front and back of membrane [CmHg] The film that can be used in the present invention has P '(O ₂ ) of 4 × 10
^-9 [the unit is the same as described above] or more, and more preferably 1 × 10 ^-8 or more. Membrane with P '(O ₂ ) less than 4 × 10 ^{-9 has a} lower gas exchange rate and the equipment is less bulky.

The presence or absence and the amount of pores (pinholes) communicating with the front and back of the membrane can be determined by measuring the oxygen / nitrogen separation coefficient α (O ₂ / N ₂ ). here When there is no communication hole, α (O ₂ / N ₂ ) varies depending on the processing conditions but ranges from 3.6 to 5.0. On the other hand, when gas permeates the membrane through the communication hole, for example, Nakagawa: high-pressure gas, α (O) as described in 18 (9), 471 (1981)
₂ / N ₂ ) is 1 or less. Therefore, when both mechanisms coexist, α (O ₂ / N ₂ ) has an intermediate value, but the speed of transmission through the communication hole is 10 ³ times lower than the speed of transmission by the dissolution / diffusion mechanism.
~ 10 ⁴ times faster, so even with the presence of a few communicating holes, α (O ₂ /
N ₂ ) drops sharply. The film that can be used in the present invention has α (O ₂ / N ₂ ) of 1.1 or more. It is preferable that α (O ₂ / N ₂ ) be high when one (or more) gas is particularly selectively dissolved from the mixed gas.

The average thickness of the entire non-porous layer through which the gas permeates by the dissolution / diffusion mechanism can be calculated from the measured value of the gas permeation rate. In other words, the permeating gas is calculated by using the equation (parallel structure) solved assuming that the permeating gas is the sum of the portion permeating through the barrier layer in the membrane by the dissolution / diffusion flow and the portion permeating through the communication hole connecting the front and back of the membrane by the Knudsen flow. , Oxygen transmission rate and nitrogen transmission rate. The calculation formula is described, for example, in JP-A-59-196706.

The present inventors have found that, even with a membrane having the same apparent oxygen permeability coefficient P '(O ₂ ), the smaller the thickness L of the non-porous layer, the higher the gas exchange capacity in a gas-liquid system. Although the details of the reason are unclear, the contribution of the communicating hole transmitting portion is smaller than that of the non-porous layer transmitting portion when transferring gas from liquid to gas or from gas to liquid. There will be. The thickness of the non-porous layer of the hollow fiber membrane that can be used in the present invention is 10 μm or less, preferably 2 μm or less, and more preferably 0.7 μm or less. However, due to manufacturing technology,
It is extremely difficult to reduce the thickness of the non-porous layer to 0.01 μm or less.

The hollow fiber used in the present invention preferably has an inner diameter of 70 to 500 μm. If it is 70 μm or less, the pressure loss of the gas or liquid flowing inside the hollow fiber is large, and the power cost increases. 500μ
Above m, it is difficult to produce a membrane having a large apparent transmission coefficient, and the membrane surface area per unit volume is small, so that there is no advantage in terms of downsizing of the unit.
The inner diameter can be selected according to the size and purpose of the device.

The film thickness is preferably 30 to 90% in terms of hollow ratio.
here When the hollow ratio is 30% or less, the surface area is smaller than the inner diameter, and the efficiency is poor. At 90% or more, the film thickness is smaller than the diameter, the mechanical strength is reduced, the probability of occurrence of breakage is increased, and the breakdown voltage is reduced.

One feature of the hollow fiber membrane used in the present invention is that it is composed of poly (4-methylpentene-1). Reason why this membrane shows a specific high gas permeation rate in a gas-liquid system compared to a polypropylene porous membrane, a PTFE porous membrane, and a so-called composite membrane in which a non-porous layer is formed on these porous membranes Although it is unknown, it is attributable to basic properties of the material, such as a large gas permeability coefficient (P (O ₂ ) = 1.6 × 10 ^-9 , the unit is mentioned above) and a small surface energy (about 24 dyne / cm). Will do. Accordingly, the material of the hollow fiber used in the present invention may be essentially composed of poly (4-methylpentene-1), and may contain other substances within a range that does not significantly affect the physical properties of the membrane. it can. That is, a composition containing 70% by volume or more of poly (4-methylpentene-1) can be used in the present invention, and an appropriate amount of additives such as an antioxidant, a fungicide, and a biofouling inhibitor are mixed. May be. 4-
A copolymer consisting of methylpentene-1 at least 70 mol% and another monomer can also be used as a material. Further, those obtained by applying treatments such as denaturing the film surface (for example, JP-A-62-119206) can also be used in the present invention.

The membrane that can be used in the present invention is described in, for example, JP-A-59-19.
6706, JP-A-59-229320, JP-A-61-101206, JP-A-61-61206
It can be manufactured by the manufacturing method disclosed in -101227. As another method, for example, poly (4-methylpentene-1) is formed on a porous poly (4-methylpentene-1) membrane.
A method of forming a heterogeneous membrane structure by the method of 1) for producing a composite membrane coated with a non-porous layer (for example, JP-A-62-45318)
And other film forming methods can be adopted.

The invention also relates to the structure of the gas-liquid contact device. An outline of a typical structure of a known hollow fiber type gas-liquid contact device is shown in a vertical partial sectional view of FIG.

The hollow fiber membrane (2) is inserted into the case (1) in the form of a fiber bundle, and is sealed with resin at the resin sealing portions (3) at both ends. The part is open at both ends. When a liquid flows into the hollow portion of the hollow fiber membrane, the liquid enters through the inlet (4), flows through the hollow portion of the hollow fiber membrane, and then exits the module through the outlet (5).
The gas is guided to the module through the inlet (6), flows outside the hollow fiber, and then out of the module through the outlet (7).
On the other hand, when the liquid flows into the outer space of the hollow fiber membrane, the inlet (6)
More liquid is introduced and discharged from the discharge port (7). The gas is introduced from the inlet (4), passes through the hollow portion of the hollow fiber membrane, and is discharged from the outlet (5).

When a specific type of gas is removed from a certain fluid by using a hollow fiber membrane type gas-liquid contact device (a typical example is deoxidation of water. Only the method of flowing a fluid from which gas is to be removed, that is, water, into the inside of the hollow fiber (internal perfusion) has been put into practical use (for example, Japanese Patent Application Laid-Open No. 60-255120). Although the reasons may be various, for example, in the hollow fiber membrane type gas-liquid contacting device having the above-described typical structure, when water flows outside the hollow fiber (external perfusion), uneven filling of the hollow fiber bundle and hollow space occur. Water channeling (drift) resulting from the twisting of the hollow fiber caused by the hydrophobicity of the yarn occurs, which short-circuits the raw water inlet and the degassed water outlet, and the dissolved oxygen concentration in the water has a certain value (for example, 0.5 ppm) or less. That is, no matter how long the flow rate of water is reduced and the contact time between water and the membrane is increased, highly deoxygenated water cannot be obtained. This is fatal in a gas-liquid contact device for the purpose of degassing, and therefore, despite the increased pressure drop and low gas exchange efficiency per membrane area, there is no short circuit in the internal perfusion type. It seems that only water degassing equipment has been put into practical use. An example of the case where the fluid from which gas is to be removed is a gas is removal of NOx from air and waste gas. In this example, NOx contained in air is removed by absorption into water or alkali through a diaphragm gas-liquid contact device. In this case as well, the NOx residual concentration in the exhaust gas is reduced to a certain value or less (for example, 0.6 ppm or less). Needs to be of a type in which waste gas flows inside the hollow fiber for the same reason as deoxidation of water.

In the present invention, the hollow fiber is incorporated into the case in the form of a superimposed or convergent sheet-like material (hereinafter, referred to as a hollow fiber sheet) formed by hollow fibers or other yarns. The hollow fiber membrane used in the present invention is capable of preventing the uneven flow of the fluid flowing outside the yarn and the short circuit between the flow paths and having a structure in which the fluid from which the gas to be removed flows in contact with the outside of the hollow fiber has a very low residual gas concentration. Can be sufficiently exhibited without impairing the structure of the gas-liquid contact device.

The shape of the hollow fiber sheet is such that the hollow fibers are
Fabrics and hollow fibers crossed at an angle of ゜ are wefts and ordinary yarns are woven or woven as warps, which can be used in the present invention. Hollow fiber gap blinds applications, can be arbitrarily set according to the use conditions, ¹ / _50-10 times of the hollow fiber outer diameter is preferably ¹ / _5-2 times more preferred. In order to increase the efficiency of filling the membrane per unit volume and to increase the throughput per membrane area by reducing the membrane resistance outside the hollow fiber, it is preferable to reduce the interval. However, when the gap is reduced, the effect of the unevenness of the hollow fiber spacing becomes large, and the efficiency is rather reduced.Therefore, depending on the degree of the unevenness of the hollow fiber spacing, it is efficient to set the gap to 0.1 mm or more. is there. When the fluid flowing outside the hollow fiber is water, the gap between the hollow fibers is most preferably 0.1 to 0.3 mm.

On the other hand, when it is desired to increase the flow rate of the fluid flowing outside the hollow fiber, when reducing the pressure loss, and when the fluid disperses a solid or gel, it is preferable to make the fluid relatively wide. If the gap is made as large as 10 times or more the outer diameter of the hollow fiber, the filling efficiency of the device decreases, and the membrane area per device volume decreases. As the shape of filling the hollow fiber sheet into the case of the gas-liquid contacting device, the shape of the gas-liquid contact that is adopted, such as the shape of a sheet wound spirally, the shape of a rod or a perforated pipe wound and filled, the shape of folded and filled, etc. Any shape can be adopted according to the type. The type of gas-liquid contact can be arbitrarily selected depending on the intended use, such as parallel flow, counter flow, cross flow, etc., but the effect of the hollow fiber of the present invention is exhibited and the hollow fiber is formed into a sheet. In order to sufficiently increase the flow rate, a cross flow type in which a fluid flows in a direction of flowing through the hollow fiber sheet surface is most preferable. As an embodiment of such a structure, as shown in the example, a hollow box-shaped case is formed by stacking and arranging hollow fiber sheets in a square box-shaped case, or a hollow fiber sheet is spirally wound around a perforated pipe, and a fluid is provided. Can be illustrated from the center toward the outer periphery or from the outer periphery toward the center.

[Effects of the Invention] The present invention eliminates the disadvantages of the gas exchange device of the porous membrane type by using the characteristic hollow fiber, that is, the limitation on the use time, the type of liquid, and the limitation on the use conditions. In addition, while maintaining the advantages of a non-porous membrane type gas exchange device made of silicon rubber or a composite membrane, by solving the disadvantages of gas permeation speed and pressure resistance, it is possible to make the device compact as well as a wide range of objects. It has the advantage that it can be used for In particular, the present invention has a far superior oxygen permeation rate to a liquid and a deoxygenation rate from a liquid as compared to a conventionally known non-porous membrane as well as a conventional porous membrane. That is surprising.

The present invention also dramatically improves gas-liquid gas exchange efficiency by incorporating the hollow fiber into a sheet shape and incorporating it into the gas-liquid contact device. This has a higher improvement effect than conventionally known homogeneous films, heterogeneous films and composite films. The reason is that the membrane of the present invention has a high gas exchange rate of the hollow fiber membrane itself in the gas-liquid system, so if the liquid side membrane resistance is reduced by improving the device structure, the original performance of the membrane is exhibited. It is presumed that it is because.

This feature is particularly exerted when applied to an application for removing gas from a certain fluid irrespective of gas or liquid, and when a fluid from which gas is to be removed flows in contact with the outside of the hollow fiber. Similarly, when the present invention is applied to an application in which a gas is supplied to a certain liquid up to near saturation regardless of the gas or the liquid, and the fluid to be supplied with the gas flows in contact with the outside of the hollow fiber, the present invention is particularly applicable. The features of the invention are exhibited. That is, in such a case, if the method of incorporating the hollow fiber into a sheet shape is not adopted, for example, in the deoxidation of water, the raw water having the dissolved oxygen amount is used.
^It is difficult to make it less than _1/20, and it is also difficult to increase the amount of dissolved oxygen to more than 95% of saturation, for example, in supplying oxygen to water. On the other hand, if the hollow fiber of the present invention is incorporated into a device in the form of a sheet and the structure such as the flow path length is optimized according to the application and use conditions, it is more compact than using a conventionally known membrane. It can be a high-performance device.

The effect of the device structure of the present invention is remarkable when the gas-liquid-gas exchange is performed to a limit as close as possible (to a point near the equilibrium point) as in the above-described examples of degassing and air supply. Also in the exchange device, it is recognized that the efficiency is improved by eliminating the drift and increasing the effective membrane area.

[Examples] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 Melt index (ASTM D1238, 260 ° C, 5 kg) 26
The poly (4-methylpentene-1) was melt-spun using a 6 mm-diameter annular nozzle at a spinning temperature of 290 ° C., a take-up speed of 120 m / min, and a draft 200, with an outer diameter of 350 μm and an inner diameter of 280 μm.
Was obtained. At this time, the temperature within the range of 5 to 35 cm below the nozzle is
After cooling at 18 ° C. with a cross wind at a wind speed of 1.0 m / sec and passing through a spinning cylinder having a length of 4 m, winding was performed at a position 5.5 m below the nozzle. The obtained hollow fiber is continuously oriented and stretched by using a roller system at a temperature of 35 ° C. and a draw ratio (DR) of 1.1.
The mixture was introduced into a hot air circulating thermostat at ℃ and kept for 5 seconds to perform heat treatment. The heat-treated yarn is further continuously rolled with a roller system at 35 ° C, cold drawing of DR1.2, 150 ° C, hot drawing of DR1.4 and 2
By performing heat fixing at 00 ° C. and DR 0.9, a hollow fiber membrane having an outer diameter of 250 μm, an inner diameter of 200 μm, and an apparent film thickness of 25 μm was obtained. This hollow fiber membrane was white, and it was possible to estimate the occurrence of voids. However, according to SEM (scanning electron microscope) observation, pores with SEM resolving power (about 50 mm) or more were observed on both the inner and outer surfaces of the hollow fiber. Was not done. The gas permeation characteristics measured by ASTM D1434 (pressure method) are as follows: P '(O ₂ ) = 7.5 × 10 ⁻⁸ (unit is as described above; the same applies hereinafter), P ′ (N ₂ ) 2.4 × 10 ⁻⁸ , α (O ₂ / N ₂ ) =
3.1 and the non-porous layer thickness calculated from this is 0.59
μm (see JP-A-59-196706).

This hollow fiber membrane (2) was used as a weft, and a 30-denier 12-filament polyester yarn was used as a warp (10) to form a hollow fiber sheet having a weft density of 25 / cm and a warp density of 1 / cm by entanglement. . This hollow fiber sheet was spirally wound as shown in FIG. 2, inserted into a case instead of the bundle of hollow fibers shown in FIG. 1, and sealed with polyurethane to produce a gas-liquid contact device. At this time, the inner diameter of the case is 35m
m, the number of enclosed hollow fibers is 3,000, the effective length of the hollow fibers excluding the sealing part is 20 cm, and the effective membrane area based on the outer surface of the hollow fibers is
0.473 cm ² .

Tap water having a temperature of 25 ° C. and a dissolved oxygen content of 7.8 ppm was placed in contact with the outside of the hollow fiber from the inlet (6) of the gas-liquid contact device.
When the inlet (4) and the outlet (5) were evacuated to 7 torr by a dry vacuum pump, the amount of dissolved oxygen in the water flowing out from the outlet (7) was determined by a polarographic method. Type oxygen analyzer (DOL manufactured by Electrochemical Instruments Co., Ltd.)
-10) was 0.5 ppm.

Comparative Example 1 A gas-liquid contact device made in exactly the same manner as in Example 1 except that a bundle of hollow fibers was inserted instead of a hollow fiber sheet, and When the same measurement was performed, the dissolved oxygen content of the effluent was 2.2 ppm.
Met. Therefore, the water flow rate was reduced to 0.1 / min and the gas-liquid contact time was increased ten times, but the dissolved oxygen concentration was reduced to only 1.2 ppm.

Comparative Example 2 The same measurement as in Comparative Example 1 was performed using the same gas-liquid contact device as in Comparative Example 1, except that water was flowed inside the hollow fiber and the pressure was reduced outside. The dissolved oxygen concentration of the effluent was 0.7 ppm when the flow rate was 1 / min, and 0.2 ppm when the flow rate was 0.1 / min.

Example 2 Poly-4-methylpentene-1 having a melt index of 26 (according to ASTM D1238) was spun at a spinning temperature of 290 ° C. and a take-up speed of 300 m / using a 6 mm diameter annular hollow fiber nozzle.
Minutes, melt spinning with draft 270, outer diameter 343μm, film thickness 34μ
m hollow fibers were obtained. At this time, a range of 3 to 35 cm below the nozzle opening was cooled by a wind having a temperature of 25 ° C. and a wind speed of 1.5 m / sec. The obtained hollow fiber was continuously subjected to amorphous drawing using a roller system at a temperature of 35 ° C. and a draw ratio (DR) of 1.05.
The hot air treatment is performed by introducing into a hot air circulating type thermostatic bath at 5 seconds and staying for 5 seconds.
Heat stretching at 50 ° C. and DR 1.4 and heat setting at 200 ° C. and DR 0.9 were performed to obtain a hollow fiber membrane having an outer diameter of 255 μm and a film thickness of 25 μm. Observation of the inner diameter surface of this film with a SEM at a magnification of 12.000 revealed that the outer surface was smooth and almost no pores were observed, and a number of fine pores of about 0.1 μm were observed on the inner surface.

0.5 g of this hollow fiber membrane is cut into a length of about 10 mm, packed in a pycnometer, evacuated to 1 × 10 ^-2 torr or less with a vacuum pump, filled with mercury, weighed, and weighed by pycnometry. The porosity was 23%. When this hollow fiber was sealed in a glass tube and the gas permeation rate was measured at 25 ° C. in accordance with the ASTM D1434 pressure method, P ′ (O ₂ ) = 1.6 × 10
^-7 (unit is as above; the same ^applies hereinafter), P '(N ₂ ) = 6.4 × 1
0 ^-8 , α (O ₂ / N ₂ ) = 2.5, calculated non-porous layer thickness is
It was 0.31 μm (see JP-A-59-196706).

This hollow fiber is used as the weft, the polyester yarn of 30 denier 12 filaments is used as the warp, and the warp knitting method has a weft density of 28.
A cord / hollow fiber and a sheet having a density of 1.5 yarns / cm and a warp density of 1.5 yarns / cm were formed. The hollow fiber sheet is spirally wound around a perforated pipe having a large number of holes and having an outer diameter of 20 mm, loaded into a case together with the perforated pipe, and sealed to form a gas-liquid contact device having the structure shown in FIG. Was made.

The effective length of the hollow fiber membrane incorporated in this gas-liquid contactor is
30 cm, sheet lamination thickness _^(1/2 of the outer diameter minus the inner diameter of the spiral sheet) is 4 cm, effective membrane area was 12.4 m ^2.

25 ° C. tap water with a dissolved oxygen concentration of 7.9 ppm flows at a flow rate of 17 / min from the inlet (6) of the gas-liquid contact device to the outside of the hollow fiber, while the inlet (4) communicating with the inside of the hollow fiber. And the outlet (5) was evacuated to 10 torr with a vacuum pump. When the dissolved oxygen concentration of the water flowing out from the outlet (7) is measured
0.3 ppm.

Example 3 The same hollow fiber membrane as used in Example 2 was used as a weft,
Using 30 denier 12 filament polyester yarn as warp, warp density of 20 / cm, warp density of 2 /
cm-shaped hollow fiber sheet was manufactured. This hollow fiber sheet was folded as shown in FIG. 4 to have a lamination density of 30 sheets / cm and a width of 1
A stack of hollow fiber sheets having a thickness of 0 cm and a thickness of 6 cm was formed. Thickness of this superimposed body with many holes of 3 mm diameter at 8 mm intervals
It was sandwiched between two 3.5 mm polypropylene porous plates and housed in a rectangular tubular housing. The two ends of the hollow fiber are liquid-tightly bonded to the housing with polyurethane resin partition walls, and the gap formed between both end surfaces of the superposed body and the side surface of the housing is filled with an adhesive to provide a gas-liquid contact device shown in FIG. Was made. The effective length of the hollow fiber of this gas-liquid contact device is 30 cm,
The effective membrane area was 8.5 cm ² . Dissolved oxygen concentration of 7.8p from the inlet (6) of this gas-liquid contacting device
pm, water at a temperature of 25 ° C. was flowed at a flow rate of 10 / min, and the inside of the hollow fiber was evacuated to 10 torr with a vacuum pump from the inlet (4) and the outlet (5). Was 0.1 ppm or less.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal front view showing a typical example of a conventionally known hollow fiber membrane type gas-liquid contact device, FIG. 2 is a perspective view of a hollow fiber bundle in which a hollow fiber sheet is spirally wound, and FIG. The figure is a longitudinal sectional view of the hollow fiber membrane type gas-liquid contact device shown in Example 2,
FIG. 4 is a conceptual perspective view in the case where a hollow fiber sheet is folded to form a superposed body, and FIG. 5 is a partially cutaway perspective view of the apparatus of the present invention shown in the third embodiment. The reference numerals in the figure are as follows. 1 ... case, 2 ... hollow fiber membrane, 3 ... resin sealing part,
4, 6 ... Inlet ... 5, 7 ... Outlet, 8 ... Cap, 9 ... Perforated pipe, 9 '... Perforated plate, 10 ... Warp.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-45318 (JP, A) JP-A-61-101227 (JP, A) JP-A-59-229320 (JP, A) JP-A-59-229320 19506 (JP, A) JP-A-55-1816 (JP, A)

Claims (4)

(57) [Claims] 1. A gas-liquid contacting device for bringing a liquid and a gas into contact with each other via a gas exchange membrane and moving or exchanging the gas through the membrane, wherein the gas exchange membrane comprises poly- (4-methylpentene-1). Consisting essentially of a material having
The apparent oxygen permeability coefficient P '(O ₂ ) at 25 ° C. is 4 × 10
^-9 [cm ³ (STP) / cm ² , sec, cmHg] or more, and a separation coefficient α (O ₂ / N ₂ ) of oxygen and nitrogen at 25 ° C. of 1.1 or more is a hollow fiber membrane. A hollow fiber membrane-type gas-liquid contact device, wherein a yarn is incorporated in a case in a state of a superimposed body or a bundle of sheet-like materials organized by hollow fibers or other yarns. 2. The hollow fiber membrane type according to claim 1, which is used for degassing from a liquid, of an external perfusion type in which a liquid flows in contact with the outside of the hollow fiber membrane and gas is permeated inside the hollow fiber membrane. Gas-liquid contact device. 3. The hollow perfusion type according to claim 1, wherein a gas mixture flows in contact with the outside of the hollow fiber membrane, and a specific kind of gas is separated and transferred to a liquid flowing inside the hollow fiber membrane. Thread film type gas-liquid contact device. 4. The hollow fiber sheet-like material according to claim 1, 2 or 3, wherein the hollow fibers arranged in parallel are braided with other yarns which are substantially perpendicular thereto. Hollow fiber membrane gas-liquid contact device.