JP5839601B2 - Hollow fiber membrane module, and filtration method and ultrapure water production system using the same - Google Patents

Description

  The present invention relates to a filtration module for performing turbidity and sterilization on relatively clear raw water or ultrapure water such as river water and groundwater, and a filtration method and ultrapure water production system using the same. . The present invention particularly relates to a hollow fiber membrane module suitable as a security filter in an ultrapure water production line and a filtration method using the same.

  In lines that produce ultrapure water used in the manufacture of electronic and electrical parts such as semiconductors and display elements, supply ultrapure water produced using microfiltration membranes, ion exchange resins, and reverse osmosis filtration membranes to use points Immediately before the filtration, it is filtered using a microfiltration membrane or an ultrafiltration membrane. This microfiltration membrane or ultrafiltration membrane functions as a security filter. As the membrane module for this application, an external pressure both-end water collecting membrane module that supplies raw water to the outside of the hollow fiber membrane and collects filtrate from both ends is mainly used (see Non-Patent Document 1). reference).

  As the usage form of the module, as shown in FIG. 6, raw water is introduced from the nozzle 52b on one end side of the hollow fiber module 50, and the nozzle on the other end side of the hollow fiber module 50 is along the outer surface of the hollow fiber membrane. Concentrated water is allowed to flow out from the pipe L7 while being circulated through the pipe 52a, and the filtration device 200 is configured to take out filtered water permeated through the hollow fiber membrane and permeated into the hollow fiber membrane from the pipe connection caps 56a and 56b, respectively. The pipe L6a connected to the cap 56a is connected to the pipe L6b connected to the cap 6b. The filtered water taken out from the cap 56a passes through the pipe L6a and the filtered water taken out from the cap 56b The pipes flow through the pipes L6b, join at the connected points, and are supplied to the use point.

  When collecting filtered water with the above-mentioned both-end water collecting type module, the flow path of the supply water in the module is narrow, so between the supply side (the nozzle 52b side) and the concentration side (the nozzle 52a side). The pressure difference is large. Therefore, the amount of permeated water on the supply side (cap 56b side) is larger than the amount of permeated water on the concentration side (cap 56a side). For this reason, there was a problem that viable bacteria easily propagated in the flow path on the concentration side with a small amount of permeated water. Also, in sterilization cleaning to disinfect pipes and modules, there are problems such as prolonged sterilization operation in the flow path on the side where the flow rate is low, and it takes a long time to start up after sterilization operation. There was a problem.

  As a method for solving such a problem, a method has been proposed in which flow rate control means is provided in the filtrate water pipe (L6b) on one end side so that the amount of permeated water on the supply side and the concentration side is substantially the same (Patent Literature). 1).

Japanese Patent Laid-Open No. 06-319959

Ito, Ogawa, “Membrane separation technology in ultrapure water production process”, Clean Technology, Nippon Kogyo Publishing, October 1998, Vol. 8, No. 10, p. 22-25

  However, when flow control means such as an orifice or a valve is provided in the above method, it is necessary to measure the flow rate in advance and adjust the throttle degree when installing the module, which requires complicated operations. It was.

  On the other hand, in recent years, the amount of ultrapure water to be used increases with the expansion of the production scale, and the ultrapure water production facilities tend to increase in size, and there is a strong demand for making the production facilities compact. Under such circumstances, a module having a high filtration capacity, that is, a module having a high filtration flow rate per module and a high filtration flow rate per unit volume is demanded.

  Therefore, the present invention provides a hollow fiber membrane module in which the flow rates flowing through the two filtrate flow paths can be made substantially equal without providing any special flow rate control means, and a filtration method and ultrapure water production system using the same. The primary purpose is to provide it. Furthermore, the present invention provides a hollow fiber membrane module that can stably obtain filtered water of good water quality for a long period of time while the scale of the apparatus is compact, and a filtration method and ultrapure water production system using the same. The second purpose is to do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor is extremely useful for solving the above problems by performing internal pressure filtration using a hollow fiber membrane module having a specific structure. The present invention has been found and the present invention has been made.

The present invention provides a yarn bundle composed of a plurality of hollow fiber membranes, a cylindrical case containing a yarn bundle and having a plurality of nozzles on the side surface, and hollow fiber membranes at both ends of the yarn bundle in the cylindrical case. comprising a pair of fixing portions sealing the gap between the outer surface and between the inner surface of the outer surface and the cylindrical case, a flow path cross-sectional area of the nozzle to the hollow fiber membrane outside of the flow path cross-sectional area S ₁ in the cylindrical case the ratio of _{S 2 (S 2 / S 1} ) provides a hollow fiber membrane module is 0.15 to 0.60.

According to the hollow fiber membrane module of the present invention, using a tubular case having a nozzle at each end, the ratio of flow path cross-sectional area S ₂ of the nozzle to the hollow fiber membrane outside of the flow path cross-sectional area S ₁ in the case (S ₂ / S ₁ ) is set to 0.15 or more and 0.60 or less so that the flow rate of filtrate water flowing out from the nozzles at both ends can be made substantially equal without using a flow rate adjusting means such as a valve or an orifice. In addition, it is possible to sufficiently suppress the growth of microorganisms in the hollow fiber membrane module and in the filtrate water pipe, and to exhibit a high filtration capacity.

  In the present invention, it is preferable that the cross-sectional areas of the plurality of nozzles are substantially the same. Thereby, it becomes easy to make the flow rate of the filtered water flowing out from each nozzle substantially equal.

  In the present invention, a plurality of small bundles formed by bundling a plurality of hollow fiber membranes in a bundle are filled in a cylindrical case in parallel, and at least at the interface position of the fixed part, compared with other parts And it is preferable to have a part with a low packing density of a hollow fiber membrane. It is particularly preferable that the low packing density portion is provided continuously from the fixing portion at one end to the fixing portion at the other end. By providing a portion having a low filling density of the hollow fiber membrane in the cylindrical case, the resistance of water flowing in the cylindrical case can be reduced. That is, even if the cross-sectional area of the channel outside the hollow fiber membrane is the same, the hollow fiber membrane is divided into small bundles and the hollow fiber membranes in each small bundle, compared to the case where all the hollow fiber membranes are combined into one bundle. In the case where the packing density is relatively high and the flow path is secured between the small bundles, the resistance (total resistance) of the water flowing in the cylindrical case can be reduced. This provides the advantage that less supply pressure is required to obtain the same filtered water flow rate.

  The hollow fiber membrane module of the present invention further includes a pair of rectifying cylinders whose one ends are sealed by a fixing portion and extend so as to surround both ends of the yarn bundle, and the pair of rectifying cylinders are isolated from the fixing portion. It is preferable that each position has an opening through which water inside the flow straightening tube can flow to the nozzle. Thereby, since the shear force which a hollow fiber membrane receives from a water flow in the vicinity of a fixed part can fully be reduced, damage to the hollow fiber membrane by a water flow can fully be suppressed. Furthermore, at least one of the pair of flow straightening tubes is provided with a plurality of through holes penetrating from the inside to the outside at a position isolated from the fixed portion, thereby reducing the flow rate from the flow straightening tube to the outside at the opening end of the flow straightening tube. It is possible to effectively prevent damage to the hollow fiber membrane due to rubbing between the open end of the flow straightening cylinder and the hollow fiber membrane. This makes it possible to continuously produce excellent quality filtered water over a long period of time.

  When the entire region where the through hole exists is divided into a first region nearer to the fixed portion and a second region farther from the fixed portion, the rectifying cylinder penetrates into the second region. It is preferable that the aperture ratio due to the holes is higher than the aperture ratio due to the through holes in the first region. That is, it is preferable that the amount of water flowing out from the inside of the flow straightening cylinder is small on the side close to the fixed part and relatively large on the side far from the fixed part. As a result, the force received by the hollow fiber membrane by the water flow in the vicinity of the fixed portion can be reduced, and the force received by the hollow fiber membrane by the water flow at the opening end of the rectifying cylinder can be effectively reduced.

The hollow fiber membrane module of the present invention preferably has a module water permeability performance of 1000 to 3000 m ³ /hr/0.1 MPa / m ³ at 25 ° C. based on the filtration part volume. In this case, a stable filtered water quality can be maintained for a long time with a large amount of filtered water. In addition, the hollow fiber membrane module of the present invention preferably has a water permeability per module at 25 ° C. of 20 to 40 m ³ /hr/0.1 MPa. In this case, since the hollow fiber membrane module can be held by one person and the handling property is remarkably improved, the hollow fiber membrane module can be attached to a filtration device having a narrow mounting pitch. Therefore, if both the water permeation performance and the water permeation amount are satisfied, the filtration device can be made more compact.

Furthermore, the present invention provides a filtration method using the hollow fiber membrane module. That is, the filtration method according to the present invention includes a yarn bundle composed of a large number of hollow fiber membranes, a cylindrical case containing the yarn bundle and having a plurality of nozzles on the side surfaces, and both ends of the yarn bundle in the cylindrical case. A pair of fixing portions sealing the outer surfaces of the hollow fiber membranes and the gap between the outer surface and the inner surface of the cylindrical case, and the flow path cross-sectional area S ₁ outside the hollow fiber membrane in the cylindrical case When filtration is performed using a hollow fiber membrane module in which the ratio (S ₂ / S ₁ ) of the channel cross-sectional area S ₂ of the nozzle is 0.15 or more and 0.60 or less, the water to be treated is removed from the hollow fiber membrane module. The filtered water that is supplied from one end to the hollow portion of the hollow fiber membrane and flows out to the outside of the hollow fiber membrane is collected from the nozzles at both ends of the cylindrical case through the pipes connected to the nozzles.

  According to the filtration method of the present invention, by performing internal pressure filtration using the hollow fiber membrane module, it is possible to collect almost the same amount of filtered water from the nozzles at both ends, so microorganisms in the module and in the filtered water piping Can be sufficiently suppressed.

  In the filtration method of the present invention, it is preferable to collect the filtered water that has flowed out of the nozzles at both ends at a position nearer to the nozzle farther than the nozzle closer to the one end. Moreover, it is preferable that the flow path cross-sectional areas of the nozzles at both ends are substantially the same. Moreover, it is preferable that piping has an internal diameter 0.80-1.20 times with respect to the internal diameter of the connected nozzle. Further, in the filtration method of the present invention, the yarn bundle is a plurality of small bundles formed by bundling a plurality of hollow fiber membranes in a cylindrical case in parallel, at least at the interface position of the fixed part, It is preferable to have a portion where the packing density of the hollow fiber membrane is lower than other portions.

  In the filtration method of the present invention, one end of the module is sealed by a fixing part, and further includes a pair of rectifying cylinders extending so as to surround both ends of the yarn bundle, and the pair of rectifying cylinders are isolated from the fixing part. It is preferable that each position has an opening through which water inside the flow straightening tube can flow to the nozzle. Thereby, even if it operates by a high filtrate flow rate, since the damage of the hollow fiber membrane by a water flow can fully be reduced, the excellent quality water filtrate can be stably manufactured over a long period of time with a compact apparatus. In the filtration method of the present invention, it is preferable that at least one of the pair of rectifying cylinders has a plurality of through holes penetrating from the outer surface to the inner surface of the rectifying cylinder at positions separated from the fixed portion. . Further, in the filtration method of the present invention, the rectifying cylinder bisects the entire region where the through hole exists into a first region closer to the fixed portion and a second region farther from the fixed portion. In this case, it is preferable that the aperture ratio due to the through hole in the second region is higher than the aperture ratio due to the through hole in the first region. When the hollow fiber membrane module used in the filtration method of the present invention has these configurations, the above effects of the present invention are further exhibited.

Further, in the filtration method of the present invention, the module water permeability performance based on the filtration part volume at 25 ° C. is preferably 1000 to 3000 m ³ /hr/0.1 MPa / m ³ , and the water permeability per module at 25 ° C. Is preferably 20 to 40 m ³ /hr/0.1 MPa.

  Moreover, this invention provides the ultrapure water manufacturing system using the said hollow fiber membrane module. That is, in an ultrapure water production system including at least an ultraviolet irradiation means, an ion exchange treatment means, and an ultrafiltration membrane treatment means, an ultrapure water production system in which the ultrafiltration membrane treatment means is the hollow fiber membrane module. provide. As a result, the entire system becomes more compact than before, and the advantage of a smaller installation area can be obtained.

  According to the present invention, there is provided a hollow fiber membrane module in which the flow rate of filtered water flowing out from the nozzles at both ends can be made substantially equal without using a flow rate adjusting means such as a valve or an orifice. Moreover, according to the filtration method and the ultrapure water production system using such a hollow fiber membrane module, it is possible to stably produce a filtered water having an excellent water quality with a high filtrate water flow rate while being compact. .

It is sectional drawing which shows typically one Embodiment of the hollow fiber membrane module which concerns on this invention. It is II-II sectional drawing of the hollow fiber membrane module shown in FIG. (A) It is the III-III sectional view taken on the line of the rectification | straightening cylinder shown in FIG. (B) It is sectional drawing which shows typically other embodiment of a rectification | straightening cylinder. (C) It is sectional drawing which shows typically other embodiment of a rectification | straightening cylinder. It is the schematic which shows an example of a structure of the filtration apparatus provided with the hollow fiber membrane module which concerns on this invention. It is a fragmentary sectional view showing typically one embodiment of the hollow fiber membrane module concerning the present invention. It is the schematic which shows an example of a structure of the filtration apparatus provided with the conventional hollow fiber membrane module. It is sectional drawing which shows typically one Embodiment of the conventional hollow fiber membrane module. It is the VIII-VIII sectional view taken on the line of the hollow fiber membrane module shown in FIG. It is the IX-IX sectional view taken on the line of the protection cylinder shown in FIG.

<Hollow fiber membrane module>
An embodiment of a hollow fiber membrane module according to the present invention will be described with reference to FIGS. A hollow fiber membrane module 10 according to this embodiment includes a yarn bundle 1 made up of a number of hollow fiber membranes 1a, a cylindrical case 2 that accommodates the yarn bundle 1, and a casting provided at both ends of the yarn bundle 1. A pair of fixing portions 3a and 3b made of an agent and a pair of rectifying cylinders 4 and 5 disposed so as to surround both ends of the yarn bundle 1 are provided. The module 10 is configured so that pipe connection caps 6a and 6b can be attached to both ends of the cylindrical case 2 by nuts 7a and 7b, respectively. By tightening the nuts 7a and 7b, the portions are sealed by the O-rings 8a and 8b arranged in the grooves of the caps 6a and 6b.

  The yarn bundle 1 is formed by a large number of hollow fiber membranes 1a. A number of hollow fiber membranes 1a can be bundled together to form a yarn bundle. However, as shown in FIG. 2, the yarn bundle 1 is preferably divided into a plurality of small bundles 1b. In particular, it is more preferable that a small bundle 1b composed of a large number of hollow fiber membranes 1a is wrapped with a net 1c. Thus, by providing the module 10 with a portion that is not filled with the hollow fiber membrane (portion with a low membrane filling density), the resistance of the water flowing outside the hollow fiber membrane 1a is reduced, and as a result, higher module water permeability. Performance can be realized. In addition, as long as it can cover the surface of the small bundle 1b and consists of a raw material which has water permeability, you may use a nonwoven fabric etc. instead of a net | network as what wraps a small bundle.

  The type of the hollow fiber membrane 1a can be appropriately selected according to the use of the module 10. Specific examples of the hollow fiber membrane 1a include an ultrafiltration membrane and a microfiltration membrane. For example, if the module 10 is used for a final filter for ultrapure water, the hollow fiber membrane 1a is preferably an ultrafiltration membrane having an average pore diameter of 0.05 μm or less (more preferably 0.02 μm or less). The material of the hollow fiber membrane 1a may be appropriately selected depending on the application, and can be selected from, for example, polyethylene, polypropylene, polysulfone, polyethersulfone, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, and polyacrylonitrile.

The hollow fiber membrane 1a has an inner area-converted short thread water permeability (25 ° C.) of 2000 L / m ² /hr/0.1 MPa (hereinafter, the unit of short thread water permeability is referred to as “LMH”) or more. Is preferably 4000 LMH or more. The inner diameter of the hollow fiber membrane 1a is preferably 0.7 to 1.0 mm, particularly preferably 0.70 mm to 0.85 mm. As will be described later, the module 10 of the present embodiment can sufficiently suppress the influence due to vibration during water flow, and therefore, by using the hollow fiber membrane having the short thread water permeability and the inner diameter, it is about twice as much as the conventional one. Module water permeability can be realized.

  The cylindrical case 2 is made of a cylindrical member having openings at both ends, and has nozzles 2a and 2b provided in the vicinity of the interfaces Fa and Fb of the fixing portions 3a and 3b. The interface of the fixed part here means a surface on one side of the fixed part where the base end of the rectifying tube is embedded. The material of the cylindrical case 2 can be appropriately selected from metals and plastics according to the application. From the viewpoint of ease of processing and weight reduction, the cylindrical case 2 is preferably made of plastics. Specific examples of plastics include polyethylene, polypropylene, polysulfone, polyethersulfone, polyvinylidene fluoride, ABS resin, and A vinyl chloride resin etc. are mentioned. Note that the number of nozzles provided in the vicinity of the interfaces Fa and Fb is not necessarily one, and a plurality of nozzles can also be provided in the part.

  A plurality of nozzles provided on the side surface of the cylindrical case 2 are provided in the vicinity of the interface between the fixing portions 3a and 3b, except for the case where one nozzle is provided only in the vicinity of the interfaces Fa and Fb between the fixing portions 3a and 3b as described above. May be. Further, one each may be provided in the vicinity of the interface between the fixing portions 3 a and 3 b and may be additionally provided in the central portion of the cylindrical case 2. It is preferable to provide one each only near the interface between the fixing portions 3a and 3b. Usually, the purpose of collecting filtered water can be achieved by providing one each in the vicinity of the interface of the fixed part. In this case, the number of members can be reduced, and at the same time, the member can be easily molded.

  The cylindrical case 2 has an outer diameter of 140 to 200 mm, a length of preferably 700 to 1400 mm, an outer diameter of 160 to 180 mm, and a length of 800 to 1100 mm. It is particularly preferred. When the cylindrical case 2 having a size in this range is used, a high module water permeability and the highest module water permeability can be realized. In addition to this, since it is possible to have the module 10 by one person with this size, there is an advantage that handling property is remarkably good. The “outer diameter” of the cylindrical case 2 herein means the outer diameter of the cylinder in the filtration region at the center of the module. The “length” of the cylindrical case 2 means the distance between both end faces of the hollow fiber membrane 1a.

この条件を満たすように流路断面積Ｓ_１を設定することにより、この部分を水が流通する際の圧損を小さくでき、高いモジュール透水量を実現できる。なお、ここでいう「モジュール透水量」とは、膜間差圧０．１ＭＰａを印加したときの２５℃における１時間当たりのろ過量（ｍ^３／ｈｒ／０．１ＭＰａ＠２５℃）をいう。また、「モジュール透水性能」とは、上記モジュール透水量をモジュールの見かけ容積、或いはろ過部容積で除した値（（ｍ^３／ｈｒ／０．１ＭＰａ）／ｍ^３＠２５℃）をいう。前者を「見かけ容積基準のモジュール透水性能」と記し、後者を「ろ過部容積基準のモジュール透水性能」と記す。ここで「見かけ容積」とは、筒状ケース２の外径から計算される断面積に配管接続キャップ６ａと６ｂの端面間の距離を乗じた値であり、「ろ過部容積」とは、筒状ケース２の内径から計算される断面積に膜有効長（固定部の界面ＦａとＦｂの距離）を乗じた値である。なお、流路断面積Ｓ_１は、下記式（２）によって算出される値である。

式中、Ｄ_１は筒状ケースの中央部における内径（ｍ）を示し、ｄ_Ｏは中空糸膜の外径（ｍ）を示し、Ｎは糸束を成す中空糸膜の本数を示す。Assuming that the cross-sectional area outside the hollow fiber membrane in the central part (filtering part) of the cylindrical case 2 is S ₁ (m ² ) and the maximum filtration flow rate of the hollow fiber membrane module is Q (m ³ / s), passage sectional area S ₁ preferably satisfies the condition represented by the following inequality (1).

By setting the flow path cross-sectional area S ₁ so as to satisfy this condition, this part can be reduced pressure loss when water flows, can achieve high module water permeability. The “module water permeability” here refers to the filtration rate per hour (m ³ /hr/0.1 MPa @ 25 ° C.) at 25 ° C. when a transmembrane pressure difference of 0.1 MPa is applied. The “module water permeability” refers to a value ((m ³ /hr/0.1 MPa) / m ³ @ 25 ° C.) obtained by dividing the module water permeability by the apparent volume of the module or the volume of the filtration part. The former is referred to as “apparent volume-based module water permeability” and the latter is referred to as “filter part volume-based module water permeability”. Here, the “apparent volume” is a value obtained by multiplying the cross-sectional area calculated from the outer diameter of the cylindrical case 2 by the distance between the end faces of the pipe connection caps 6a and 6b. This is a value obtained by multiplying the cross-sectional area calculated from the inner diameter of the case 2 by the effective membrane length (distance between the interface Fa and Fb of the fixed portion). Incidentally, the flow path cross-sectional area S ₁ is the value calculated by the following equation (2).

In the formula, D ₁ represents the inner diameter (m) at the center of the cylindrical case, d _O represents the outer diameter (m) of the hollow fiber membrane, and N represents the number of hollow fiber membranes forming the yarn bundle.

Nozzles 2a, 2b are, when the flow path cross-sectional area and _S ^{2 (m} 2), the ratio between the flow path cross-sectional area ^{_{S 1 (m 2) (S}} 2 / S 1) is 0.15 or more It must be 0.60 or less. In this range, the flow rate of filtered water flowing out from the nozzles at both ends can be made substantially equal without using a flow rate adjusting means such as a valve or an orifice, and a high filtration capacity can be shown. This value is preferably 0.20 or more and 0.50 or less, and more preferably 0.25 or more and 0.45 or less. If it is less than 0.15, the tendency of the balance of the amount of filtered water flowing out from each nozzle will become stronger, or the pressure loss will increase and the module water permeability will tend to be lowered. Moreover, when it exceeds 0.60, the tendency for the balance of the filtrate amount which flows out out of each nozzle to collapse will become strong. By the 0.60, relative to the flow resistance R _L during pipe connected to the nozzle portion and which, since the flow resistance R _M in the cylindrical case in the hollow fiber membrane outer is relatively small, cylindrical The position of the watershed where the filtered water in the center of the case flows to the nozzle 2a side or the nozzle 2b side is mainly governed by the flow resistance _RL in the nozzle part and the pipe connected to it, as a result. It is considered that the flow rate from each nozzle becomes equal. In contrast, when it exceeds 0.60, the influence of the flow resistance R _M in the hollow fiber membrane within the outer tubular case can not be ignored, the supply side by impact of pressure on the supply side of the water to be treated is high It is thought that a large amount of filtered water flows out from a nozzle close to.

When using the hollow fiber membrane module of the present embodiment, a standard piping material normally defined by JIS or the like is connected. Therefore, it is preferable that the nozzle of the present embodiment has a flow path having a shape corresponding to the inner diameter of the pipe. That is, it is preferable that the flow path of the nozzle is circular and has substantially the same inner diameter as the pipe to be connected. As a result, an advantage that the connection between the nozzle and the pipe is facilitated and an advantage that a stay portion is generated in the connection portion and the proliferation of microorganisms can be prevented can be obtained. The ratio of the inner diameter _{D L} of the pipe and the internal diameter _{D M} of the nozzle _(D M / _{D L)} is, it preferably 0.80 to 1.20, 0.90 to 1.15 Particularly preferred. Moreover, it is preferable that the flow-path cross-sectional area of nozzle 2a, 2b is mutually substantially the same from a viewpoint which makes the flow volume of the filtrate water which flows out out from each nozzle substantially the same.

  The fixing portions 3 a and 3 b are made of a casting agent that seals the outer surfaces of the hollow fiber membrane 1 a and the gap between the outer surface and the inner surface of the cylindrical case 2 at both ends of the yarn bundle 1 in the cylindrical case 2. Is. A thermosetting resin such as an epoxy resin or a urethane resin is suitable as the casting agent that forms the fixing portions 3a and 3b. By fixing and sealing both ends of the yarn bundle 1 with the fixing portions 3a and 3b, the hollow portions of the hollow fiber membrane 1a are opened at both end surfaces of the yarn bundle 1. The fixing portions 3a and 3b also serve to seal the openings of the base end portions 4a and 5a of the rectifying cylinders 4 and 5.

  The rectifying cylinders 4 and 5 extend from the positions of the interfaces Fa and Fb of the fixing portions 3a and 3b toward the center of the module 10, respectively, and surround the yarn bundle 1 near the fixing portions 3a and 3b. Yes. The material of the rectifying cylinders 4 and 5 may be appropriately selected according to the application, and examples thereof include polyethylene, polypropylene, polysulfone, polyethersulfone, polyvinylidene fluoride, ABS resin, and vinyl chloride resin.

  As described above, in the pair of rectifying cylinders 4 and 5, the openings of the base end portions 4a and 5a are sealed by the fixing portions 3a and 3b, respectively. That is, the base end part 4a of the rectifying cylinder 4 is embedded in the fixed part 3a, and the base end part 5a of the rectifying cylinder 5 is embedded in the fixed part 3b. The arrangement method of the rectifying cylinders 4 and 5 is generally a method in which the base end portions 4a and 5a are embedded and fixed in the fixing portions 3a and 3b, respectively. However, the module 10 is manufactured through a process in which the rectifying cylinders 4 and 5 are fixed in advance to the cylindrical case 2 and then the base ends 4a and 5a of the rectifying cylinders 4 and 5 are embedded in the fixing parts 3a and 3b. Also good.

  The rectifying cylinders 4 and 5 are opened without sealing the openings of the end portions 4b and 5b. These openings are located at positions separated from the interfaces Fa and Fb of the fixing portions 3a and 3b, respectively, and play a role of circulating water inside the rectifying cylinders 4 and 5 to the nozzles 2a and 2b. That is, the water in the rectifying cylinder 4 flows out from the opening of the tip 4b into the space between the yarn bundle 1 and the cylindrical case 2 and passes through the gap between the inner surface of the cylindrical case 2 and the outer surface of the rectifying cylinder 4. It is discharged from the nozzle 2a. Similarly, the water in the rectifying cylinder 5 flows out from the opening of the tip 5 b into the space between the yarn bundle 1 and the cylindrical case 2, and the gap between the inner surface of the cylindrical case 2 and the outer surface of the rectifying cylinder 5. Through the nozzle 2b.

  The openings of the tip portions 4b and 5b of the rectifying cylinders 4 and 5 are preferably at least 30 mm away from the interfaces Fa and Fb of the fixed portion, respectively, and more preferably 40 mm or more. That is, it is preferable to install the rectifying cylinders 4 and 5 so as to protrude from the respective interfaces Fa and Fb of the fixing portions 3a and 3b with the above length. Furthermore, it is preferable that the opening of the tip portions 4b and 5b is located closer to the center of the module than the opening of the nozzle. By surrounding the both ends of the yarn bundle 1 with the rectifying tubes 4 and 5 having such a length, the hollow fiber membrane 1a can be effectively prevented from being damaged in the vicinity of the interfaces Fa and Fb. This is because the flow of water in the direction crossing the hollow fiber membrane 1a occurs at a position away from the interfaces Fa and Fb of the fixing portions 3a and 3b, so that the shearing force applied to the hollow fiber membrane 1a is extremely near the interfaces Fa and Fb. This is thought to be due to mitigation.

  Moreover, it is preferable that at least one of the rectifying cylinders 4 and 5 has a plurality of through holes 4c penetrating from the inner surface to the outer surface. The through hole 4c functions as an opening through which the water inside the rectifying cylinders 4 and 5 flows to the nozzles 2a and 2b. A water flow is generated across the hollow fiber membrane bundle at the tip portions 4b and 5b of the rectifying cylinders 4 and 5, but when operating with a large amount of filtered water, the hollow fiber membrane tends to be pressed against the tip portion and damaged by the water flow. Comes out. And in a severe case, a hollow fiber membrane may be damaged and the quality of filtered water may be reduced. On the other hand, by providing the plurality of through holes 4c, the amount of water flowing out from the opening at the tip can be reduced, and damage to the hollow fiber membrane due to the water flow can be effectively prevented.

  The through holes are preferably at least 30 mm apart from the interfaces Fa and Fb of the fixing part, and more preferably 40 mm or more. Thereby, damage to the hollow fiber membrane 1a in the vicinity of the interfaces Fa and Fb can be effectively prevented. This is because the flow of water in the direction crossing the hollow fiber membrane 1a occurs at a position away from the interfaces Fa and Fb of the fixing portions 3a and 3b, so that the shearing force applied to the hollow fiber membrane 1a is extremely near the interfaces Fa and Fb. This is thought to be due to mitigation.

  In the module 10 according to the present embodiment, since the yarn bundle 1 is formed by the four small bundles 1b, a region where the hollow fiber membrane 1a is not filled is formed in the module 10 as described above. That is, as shown in FIG. 2, the hollow fiber membrane 1a is not filled in the concave portion 1e on the outermost surface of the yarn bundle 1 formed by the central portion 1d of the yarn bundle 1 and the two adjacent small bundles 1b. Since the unfilled portions (for example, 1d and 1e) function as a flow path for the filtrate water that has flowed out of the small bundle, the pressure loss can be reduced, and as a result, the effect of improving the module performance can be realized.

  The shape of the through hole 4c may be any shape such as a circle, an ellipse, a polygon, or a star, but may be a circle as shown in FIGS. 3 (a) and 3 (b) or as shown in (c). A rectangular slit mold is suitable for molding. Moreover, as a dimension of the through-hole 4c, it is preferable that the maximum dimension of a hollow fiber membrane longitudinal direction is the range of 1-10 mm, and it is especially preferable that it is the range of 2-8 mm. By doing so, it is possible to prevent the hollow fiber membrane from being pulled into the through hole 4c and being damaged. In addition, when the dimension of a through-hole is changing between the inner surface and outer surface of a rectification | straightening cylinder, it is preferable that the value of an inner surface side is said range.

式中、Ｄ_３は整流筒の先端部における内径（ｍ）を示し、ｄ_Ｏは中空糸膜の外径（ｍ）を示し、Ｎは糸束を成す中空糸膜の本数を示す。Sum (hereinafter, referred to as the total opening area S ₃₎ of the opening area of each through hole 4c is flow-guide cylinder of the tip 4b, 0.4 times or more relative to the flow path cross-sectional area S ₄ in the rectifier tube at 5b It is preferably 1.0 times or less. More preferably, it is 0.5 times or more and 0.8 times or less. Incidentally, the flow path cross-sectional area S ₄ is a value calculated by the following equation (3).

In the formula, D ₃ represents the inner diameter (m) at the tip of the rectifying cylinder, d _O represents the outer diameter (m) of the hollow fiber membrane, and N represents the number of hollow fiber membranes forming the yarn bundle.

  When the entire region where the through-hole 4c is present is divided into two equal parts, the first flow region closer to the fixing portions 3a and 3b and the second region farther from the fixing portions 3a and 3b. The aperture ratio due to the through hole 4c in the second region is preferably higher than the aperture ratio due to the through hole 4c in the first region. That is, it is preferable that the amount of water flowing out from the inside of the flow straightening cylinder is small on the side close to the fixed part and relatively large on the side far from the fixed part. As a result, the force received by the hollow fiber membrane by the water flow in the vicinity of the fixed portion can be reduced, and the force received by the hollow fiber membrane by the water flow at the opening end of the rectifying cylinder can be effectively reduced.

  As for the arrangement of the through holes 4c, specifically, as shown in FIG. 3 (a), a group of through holes arranged so as to surround the periphery of the cylinder are arranged at equal intervals in the length direction of the hollow fiber membrane (same as above). (See the double-headed arrow in the figure) and the diameter of the through-hole group in the position near the fixing portions 3a, 3b of the through-hole group is relatively small, and the through-hole group in the position far from the fixing portion There is a mode in which the opening diameter is relatively large. Further, as shown in FIG. 3 (b), the shape of each through hole is made the same, and the pitch of the through hole group in the length direction of the hollow fiber membrane is gradually increased from a position close to the fixing portions 3a and 3b to a position far from the fixed portion 3a, 3b. It is good also as an aspect which makes small (refer the double arrow in the figure). Moreover, as shown in FIG.3 (c), when providing a slit type | mold through-hole, the aspect which enlarges gradually the opening dimension of the hollow fiber membrane length direction of a slit from the position close | similar to the fixing | fixed part 3a, 3b. It is good.

  In the above embodiment, the case where the openings of the tip portions 4b and 5b of the rectifying cylinders 4 and 5 function as openings for circulating the water inside the rectifying cylinders 4 and 5 to the nozzles 2a and 2b is exemplified. Is not limited to this. For example, as shown in FIG. 5, a mode in which an opening is provided on the side surface of the rectifying cylinder without providing a gap between the outer diameter of the tip portion 14 b of the rectifying cylinder and the inner diameter of the cylindrical case 2 can be employed. In this aspect, it is preferable that the inner diameter of the tip end portion 14b of the rectifying cylinder and the inner diameter of the cylindrical case 2 are made substantially equal. By doing in this way, it can prevent that a hollow fiber membrane contacts and damages the internal-surface corner | angular part of this front-end | tip part.

  In the hollow fiber membrane module 20 shown in FIG. 5 described above, the rectifying cylinder 14 is formed of a cylindrical member whose diameter increases from the base end portion 14a toward the tip end portion 14b, and the tip end portion 14b is joined to the inner surface of the cylindrical case 2. ing. A through hole 14c is formed in the side surface of the flow straightening tube, and water in the flow straightening tube flows out from the through hole 14c to the outside of the flow straightening tube, and passes through a gap between the outer surface of the flow straightening tube and the inner surface of the cylindrical case 2. The nozzle can flow out. From the viewpoint of effectively suppressing damage to the hollow fiber membrane 1a due to water flow, the position of the through hole 4c is preferably at least 30 mm away from the interface Fa of the fixing portion, and more preferably 50 mm or more away. The shape and dimensions of the through hole are as described above. In FIG. 5, the illustration of the yarn bundle 1 and the like is omitted.

  The nozzle and the pair of rectifying cylinders may have the same shape and dimensions on one end side and the other end side, or may have different shapes and dimensions. It is preferable to design the shape and dimensions so that the flow resistance when water flows from the inside of the flow straightening cylinder to the nozzle is substantially the same. When these are made into the same shape and dimension, since it has the advantage which can make flow resistance substantially the same and can reduce the member kind at the time of producing a case, it is more preferable.

By the above-described configuration, it is possible to modules water permeability of the filtration unit volume basis to obtain a hollow fiber membrane module is 1000~3000m ³ /hr/0.1MPa)/m ³ @ 25 ℃. When used for the production of ultrapure water, the module water permeability performance based on the filtration section volume is preferably 1100 to 2300 m ³ /hr/0.1 MPa) / m ³ @ 25 ° C., preferably 1200 to 2000 m ³ / hr. /0.1 MPa) / m ³ @ 25 ° C. is particularly preferable. The hollow fiber membrane module in this range can maintain a stable filtered water quality for a long period of time with a large amount of filtered water. Moreover, it is preferable that the module water permeability performance of the filtration part volume reference | standard is in the said range, and the water permeability per module is 20-40 m < ³ > /h/0.1MPa@25 degreeC. A hollow fiber membrane module in this range can be held by one person and has excellent handling properties, and can be attached to a filtration device having a narrow mounting pitch. Therefore, coupled with the large amount of filtered water per module, the filtering device can be made more compact.

  As shown in FIGS. 7 to 9, a protection cylinder 40 having a large number of holes 40 a is known as a means for protecting the end of the yarn bundle 1. The protective cylinder 40 is intended to restrain the outer periphery of the yarn bundle 1, thereby preventing excessive vibration of the hollow fiber membrane 1a and suppressing breakage of the hollow fiber membrane 1a. However, when filtration is performed over a long period of time using a hollow fiber membrane module equipped with the protective cylinder 40, the hollow fiber membrane 1a continuously receives a unidirectional force from the water flow, thereby creeping the hollow fiber membrane 1a. Destruction is considered to occur. That is, it is difficult to prevent creep-like breakage by a method of simply restraining the outer periphery of the yarn bundle 1, and it is considered that damage due to water flow cannot be sufficiently reduced.

<Filtration method>
A method for filtering the water to be treated (raw water) using the hollow fiber membrane module 10 will be described with reference to FIG. The filtration apparatus 100 shown in FIG. 4 is for performing the internal pressure type filtration which supplies to-be-processed water to the hollow part of the hollow fiber membrane 1a, and filters outside. The filtration device 100 includes a module 10, a pipe L <b> 1 that supplies water to be treated to the module 10, pipes (filtrated water discharge pipes) L <b> 2 and L <b> 3 that discharge filtered water and concentrated water from the module 10, and midway between these pipes It consists of a pressure gauge (Pi, Pf, Po) and valves (V1 to V3) arranged.

  First, the module 10 is arranged vertically. The treated water supply pipe L1 is connected to the pipe connection cap 6b, and the pipe L3 for discharging concentrated water is connected to the pipe connection cap 6a. Further, the filtrate discharge pipes L2a and L2b are connected to the upper nozzle 2a and the lower nozzle 2b of the cylindrical case 2, respectively. If the module is arranged vertically, the air in the module can be easily replaced with water without generating an air reservoir when water to be treated is introduced and the module is filled with water.

  The treated water is supplied to the hollow portion of the hollow fiber membrane 1a by introducing the treated water into the module 10 through the treated water supply pipe L1. The filtered water flowing out from the outer surface side of the hollow fiber membrane 1a is collected from both the upper nozzle 2a and the lower nozzle 2b. By performing such internal pressure filtration with the module 10, it is possible to stably obtain filtered water with good water quality for a long period of time without causing damage to the hollow fiber membrane 1a.

  It is preferable to perform the filtration operation while allowing about 2 to 5% of the supplied water amount to flow out as concentrated water from the hollow portion of the upper hollow fiber membrane 1a. In this way, fine particles or the like excluded by the hollow fiber membrane 1a are discharged out of the module 10, so that the membrane surface is less likely to be clogged, and a stable amount of filtered water can be obtained over a longer period of time.

  As shown in FIG. 4, the filtrate discharge pipe L2b connected to the lower nozzle 2b rises with an elbow and merges with the other filtrate discharge pipe L2a. The upper and lower filtered water discharge pipes L2a and L2b are merged near the nozzle located farther than the nozzle located near the side where the treated water is supplied, and led to the side opposite to the side where the treated water is supplied. It is preferable to do. As a result, the flow resistance in the filtered water module 10 and the flow resistance in the filtrate discharge pipe L2 are balanced, and as a result, the amount of filtrate from the upper nozzle and the amount of filtrate from the lower nozzle are almost the same. Become. Thereby, the growth of microorganisms in the module and in the filtrate pipe can be sufficiently suppressed. In addition, there is no need to provide a flow rate adjusting valve in the filtrate discharge pipe L2 in order to balance the amount of filtrate flowing out from the nozzles 2a, 2b, and there is an advantage that the number of valves can be reduced as a result.

  The filtrate discharge pipes L2a and L2b preferably have an inner diameter that is 0.80 to 1.20 times the inner diameter of the connected nozzle. Within this range, the pressure loss at the connecting portion can be reduced to a negligible level, and problems due to the occurrence of water retention (problems of prolonged sterilization operation and long time for startup after sterilization operation) Problem) does not occur.

  In addition, although the example of the apparatus which attached one hollow fiber membrane module in FIG. 4 was shown, in an actual ultrapure water manufacturing apparatus, several hollow fiber membrane modules are attached and filtered water from each module is attached. It is customary to collect the filtered water from each module in a lump by connecting the pipe to a collecting pipe having a large inner diameter. In this case, as shown in FIG. 4, the filtrate drain pipes L2a and L2b from the upper and lower nozzles of each module may be connected, and the connection pipe may be connected to the above-mentioned collective pipe. The filtered water discharge pipes L2a and L2b can be individually connected to the collecting pipe.

<Ultrapure water production system>
The hollow fiber membrane module can be applied to an ultrapure water production system. In general, when producing ultrapure water, primary pure water production equipment combining raw water with coagulating sedimentation equipment, sand filtration equipment, activated carbon filtration equipment, reverse osmosis membrane filtration equipment, ion exchange resin tower, degassing tower, ultraviolet irradiation equipment, etc. In this way, pure water is obtained. The pure water is further processed by an ultrapure water production apparatus including an ultraviolet irradiation device, an ion exchange resin tower, and an ultrafiltration membrane device to obtain ultrapure water. The ultrapure water production apparatus may further include a reverse osmosis membrane filtration apparatus.

  In the production of ultrapure water, after obtaining pure water with the primary pure water production apparatus, at least ultraviolet irradiation means such as the ultraviolet irradiation apparatus, ion exchange treatment means such as an ion exchange resin tower, and an ultra membrane filtration apparatus. It is preferable to use the hollow fiber membrane module of the present embodiment as the ultrafiltration water filtration means in the ultrapure water production system including the ultrafiltration membrane filtration means. As a result, the entire system becomes more compact than before, and the advantage of a smaller installation area can be obtained. In particular, it is preferable that after the treatment by the ultraviolet irradiation means and the ion exchange treatment means, the treatment is finally carried out by the ultra membrane filtration treatment means immediately before the use point (use location). By doing so, even if the deterioration material of the ion exchange resin used in the ion exchange treatment means is mixed, it can be removed by the ultrafiltration process at the later stage, and the ultrapure water with good water quality can be stably used at the point of use. Can be supplied.

  In the production of ultrapure water, it is preferable to perform the filtration operation in a range where the transmembrane pressure difference (see the column of “Measurement of module water permeability” described later) is 0.5 to 3.0 MPa. 0.7 to 2.0 MPa is more preferable, and 0.9 to 1.5 MPa is particularly preferable. If it is this range, the filtration water of favorable water quality can be stably obtained over a long period of time with a large amount of filtrate water.

In the following examples and reference examples, a polysulfone ultrafiltration membrane was used as the hollow fiber membrane. The characteristics are shown below.
Inner diameter / outer diameter: 0.75 mm / 1.35 mm,
Internal surface area converted short thread water permeability: 4500 LMH (measured value at membrane effective length of 5 cm),
Tensile strength: 5.0 MPa,
Tensile elongation at break: 120%.

  The water permeability of the hollow fiber membrane is 25 ° C. ultrafiltration filtered water (water filtered through an ultrafiltration membrane with a molecular weight cut off of 4000) permeated from the inner surface to the outer surface of a 50 mm long hollow fiber membrane. The amount of water (LMH). In calculating the water permeability, the effective membrane area was converted on the inner surface. The breaking strength and breaking elongation of the hollow fiber membrane were measured using an autograph AGS-5D manufactured by Shimadzu Corporation at a sample length of 30 mm and a pulling speed of 50 mm / min. The breaking strength (MPa) is a value calculated by dividing the breaking load per hollow fiber membrane by the cross-sectional area of the membrane before pulling. The elongation at break (%) is the ratio of the length stretched to break to the original length.

[Example 1]
<Production of hollow fiber membrane module>
As the cylindrical case, a transparent polysulfone having the same configuration as the cylindrical case 2 shown in FIG. 1 was used. The dimensions of this cylindrical case are as follows.
Cylindrical inner diameter / outer diameter in the filtration region: 154 mm / 170 mm,
Inner diameter / outer diameter of cylindrical part in nozzle part: 162 mm / 183 mm,
Nozzle inner diameter: 58 mm,
Length of cylindrical case / distance between nozzle centers: 1050 mm / 872 mm.

Two cylinders made of transparent polysulfone (sizes are as follows) used as a rectifying cylinder were prepared.
Inner diameter / outer diameter of the base end: 142 mm / 147 mm,
Inner diameter / outer diameter of the tip: 142 mm / 146 mm,
Length: 135mm,
Four rectifications were provided on the side surface of the rectifying cylinder, and these ridges were joined to the inner surface of the cylindrical case to fix the rectifying cylinder to both ends of the cylindrical case in advance.

  Four small bundles formed by wrapping 1750 hollow fiber membranes with a polyethylene net were prepared. The hollow part was closed to a position of about 2 mm from both ends of the hollow fiber membrane. Thereafter, four small bundles were inserted into a rectifying cylinder provided in a cylindrical case, and a thermosetting epoxy resin was injected from both ends by centrifugal casting to solidify it. A hollow fiber membrane module was produced by heating to 50 ° C. and curing, cutting both ends of the hollow fiber membrane, and opening the hollow portion of the hollow fiber membrane.

This hollow fiber membrane module had a length between cut end faces (distance between both end faces of the hollow fiber membrane) of 1045 mm and an effective membrane length of 930 mm. A pipe connection cap made of polysulfone was joined to both end faces of the hollow fiber membrane module via O-rings. The distance between the end faces of both pipe connection caps was 1180 mm. Then, the value of the flow path cross-sectional area S ₂ of S ₁ and the nozzle cross-sectional area hollow fiber membrane outer channel in the cylindrical case portion of the hollow fiber membrane module, respectively ^{8.6 × 10 -3 m 2, 2} . 6 × 10 ⁻³ m ² and S ₂ / S ₁ was 0.31. The module weighed 34 kg when the internal water was completely dripped, and could be carried alone.

<Water flow test>
Using the hollow fiber membrane module, an apparatus having the same configuration as the internal pressure filtration apparatus shown in FIG. 4 was constructed. A rotor type flow meter was provided on the downstream side of the valve V3 of the pipe L3 for discharging the concentrated water and on the downstream side of the valve V2 of the filtered water discharge pipe L2. In addition, an ultrasonic flow meter is provided at a position before the filtrate discharge pipe L2b joins the upper pipe L2a so that the flow rate of water discharged from the lower nozzle 3b through the pipe L2b can be measured. The inner diameters of the pipes L2a and L2b are 51 mm.

In the module, pure water at 25 ° C is filtered and the flow rate of filtered water is adjusted to 10 m ³ / hr, and the amount of concentrated water is adjusted to 0.3 m ³ / hr to adjust the opening of the valves V1 and V3 to start water flow. The air was replaced with water. In addition, the valve V2 was fully opened at the time of water flow.

(Measurement of module water permeability)
Then, the filtered water flow rate while fixing the concentrated water to 0.3 m ³ / hr went raised stepwise passing water from ^12m 3 / hr up to ^36m 3 / hr. The indicated values of the pressure gauges Pi, Po, and Pf at each stage were read to determine the transmembrane pressure difference. The transmembrane pressure difference ΔP (MPa) is calculated by the following equation (4), where Pi is the pressure of the water to be treated, Po is the pressure of the concentrated water, Pf is the pressure of the filtered water, and H is the height correction value. Value. The height correction value H (MPa) is a value calculated by the following formula (5) when the height from the floor surface at each measurement position of Pi, Po, Pf is Hi, Ho, Hf [m]. is there.

A graph of each filtrate water amount and the transmembrane pressure difference was drawn, and the filtrate water flow rate when the transmembrane pressure difference was 0.1 MPa was determined to be 28 m ³ /hr/0.1 MPa @ 25 ° C. This value is the module water permeability. From this value and the module dimensions (outer diameter 170 mm, distance between pipe connection caps 1180 mm), the apparent volume-based module water permeability was calculated as 1050 m ³ /hr/0.1 MPa / m ³ @ 25 ° C. This value is about 1.8 times that of the module described in Non-Patent Document 1. The module permeation performance based on the filtration section volume calculated from the module water permeability, the cylindrical case inner diameter (154 mm), and the membrane effective length (930 mm) is 1620 m ³ /hr/0.1 MPa / m ³ @ 25 ° C. is there. In addition, when the flow rate from the lower nozzle was measured while passing through each filtered water flow rate, the flow rate from the lower nozzle showed almost 1/2 of the filtered water flow rate, and almost the same amount from the upper and lower nozzles. It was confirmed that the filtered water was flowing out. The results are shown in Table 1. Incidentally, the value obtained by subtracting the flow rate Q _b of the lower nozzle from the filtered water flow rate Q and the flow rate Q _a of the upper nozzle, the ratio Q _a of the flow rate Q _b of the lower nozzle and the flow rate Q _a of the upper nozzle / describing the value of _{Q b.}

[Examples 2 to 5, Comparative Example 1]
A hollow fiber membrane module according to Examples 2 to 5 and Comparative Example 1 was produced in the same manner as Example 1 except that a cylindrical case having a different nozzle inner diameter was used. The nozzle position was set so that the apparent volume and the filtration part volume of these hollow fiber membrane modules were the same as in Example 1. And the filtration apparatus was comprised like Example 1 except having changed the internal diameter of piping L2a and L2b, and it tested and evaluated similarly to Example 1. FIG. The results are shown in Table 1. In Examples 2 to 5, it was confirmed that almost the same amount of filtered water had flowed out from the upper and lower nozzles, indicating a large module water permeability. On the other hand, in Comparative Example 1, the filtration resistance was large and the module water permeability performance was lowered. Moreover, since the transmembrane pressure difference exceeded 0.3 MPa, water could not be passed at a filtrate water flow rate of 36 m ³ / h.

[Example 6]
A hollow fiber membrane module according to Example 6 was produced in the same manner as in Example 1 except that the hollow fiber membrane bundle was not divided into four bundles but made into one bundle. That is, one bundle formed by wrapping 7000 hollow fiber membranes with a polyethylene net was prepared to produce a hollow fiber membrane module. In addition, the apparent volume and filtration part volume of this hollow fiber membrane module are the same as Example 1. Next, a filtration apparatus was constructed in the same manner as in Example 1, and tests and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1. In Example 6, it was confirmed that almost the same amount of filtered water had flowed out from the upper and lower nozzles, indicating a large module water permeability.

[Comparative Example 2]
A hollow fiber membrane module according to Comparative Example 2 in the same manner as in Example 1 except that four small bundles formed by wrapping 1550 hollow fiber membranes with a polyethylene net and using a cylindrical case with a nozzle diameter of 42 mm Was made. The nozzle position was set so that the apparent volume and the filtration part volume of this hollow fiber membrane module were the same as in Example 1. Subsequently, except that the filtrate discharge pipe was changed to a pipe having an inner diameter of 42 mm, a filtration apparatus was configured in the same manner as in Example 1, and tests and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1. In this comparative example 2, the balance of the flow rate of filtrate from the upper and lower nozzles was greatly lost, and a large amount of filtrate flowed out from the upper nozzle.

[Comparative Example 3]
A hollow fiber membrane module according to Comparative Example 3 was produced in the same manner as in Example 1 except that 7700 hollow fiber membrane bundles were used as one bundle and a cylindrical case having a nozzle diameter of 77 mm was used. That is, a hollow fiber membrane module was prepared by preparing one bundle formed by wrapping 7700 hollow fiber membranes with a polyethylene net. The channel cross-sectional area ratio S ₂ / S _{1 of the} module was 0.61. The nozzle position was set so that the apparent volume and the filtration part volume of this hollow fiber membrane module were the same as in Example 1. Next, a filtration apparatus was constructed in the same manner as in Example 1, and tests and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1. In Comparative Example 3, the balance of the filtrate water flow rate from the upper and lower nozzles was greatly lost, and a large amount of filtrate water flowed out from the lower nozzle.

[Example 7]
A hollow fiber membrane module according to Example 7 was produced in the same manner as in Example 1 except that a rectifying cylinder (see FIG. 3A) in which the following through hole was formed on the side surface of the rectifying cylinder was used. .
The flow straightening cylinder used in this example has the following shape.
Inner diameter / outer diameter of the base end: 142 mm / 147 mm,
Inner diameter / outer diameter of the tip: 142 mm / 146 mm,
Length: 135mm,
Through hole:
First line: diameter 4 mm, hole center position 53.5 mm from the base end, 18 at 15 degree intervals Second line: diameter 4 mm, hole center position 63.0 mm from the base end, 17 at 15 degree intervals Third line: diameter 5 mm, hole center position 72.5 mm from the base end, 18 at 15 degree intervals Fourth line: diameter 5 mm, hole center position 82.0 mm from the base end, 14 at 15 degree intervals 5th line: diameter 6 mm, hole center position 91.5 mm from the base end, 18 at 15 degree intervals 6th line: diameter 6 mm, hole center position 101.0 mm from the base end, 17 at 15 degree intervals Line 7: Diameter 7 mm, hole center position 110.5 mm from the base end, 24 at 15 degree intervals Line 8: Diameter 7 mm, hole center position 120.0 mm from the base end, 24 at 15 degree intervals From the first line to the eighth line, the through holes are arranged in a staggered manner.
In the first to sixth lines, no holes are provided in the range of 45 ° to the left and right with respect to the central axis of the rectifying cylinder, and through holes are provided in the range of 45 ° to the left and right with respect to the central axis of the nozzle The rectifying cylinder was placed in the cylindrical case so that it did not exist. In the fourth row, the number of projections for fixing to the cylindrical case and the position of the holes overlaps at three locations, so the number of 14 rows is 14.

The total opening area of the through holes is 226, 214, 353, 275, 509, 481, 924 from the side closest to the base end of the flow straightening tube (first row) to the far side (eighth row). 924 mm ² . The through hole is larger on the side farthest than the side closest to the base end.

In addition, the hollow fiber membrane module of the present example has a flow path cross-sectional area ratio S ₂ / S ₁ of 0.31, and the weight is 34 kg in a state where the internal water has dripped completely, and it can be carried alone. It was.

(Measurement of module water permeability)
A filtration device was configured using the hollow fiber membrane module of this example, and the module water permeability was measured in the same manner as in Example 1. The hollow fiber membrane module of this example had a module water permeability of 29 m ³ /hr/0.1 MPa @ 25 ° C. From this value and the module size, apparent volume reference of the module water permeability 1090m ^{3 /hr/0.1MPa/m 3} @ 25 ℃, module water permeability of the filtration unit volume basis is 1690m ³ /hr/0.1MPa/m ³ Calculated as @ 25 ° C. Also in the present embodiment, the ratio Q _a / Q _b between the flow rate Q _a from the upper nozzle and the flow rate Q _b from the lower nozzle is approximately 1.0 in the same manner as in the first embodiment. Almost the same amount of filtered water was flowing out from the nozzle.

(Leak test)
Subsequently, water flow was performed for 3 months under the conditions of a concentrated water amount of 0.3 m ³ / hr and a filtrate water flow rate of 36 m ³ / hr. The module was removed from the device every month and a leak test was performed as follows to check for the presence of leaks. That is, after removing the pipe connection caps at both ends, the module was immersed in a water tank to fill the interior with pure water. Next, the nozzle on one side was sealed with a stopper, and an air pipe was connected to the other nozzle. Air pressure was gradually applied to 0.2 MPa, and both ends of the module were observed to confirm whether or not air bubbles continued to emerge from the hollow portion. The hollow fiber membrane module of this example had no leakage even after 3 months.

[Example 8]
A cylindrical member whose diameter increases downward instead of a cylinder having a constant diameter, except that a rectifying cylinder (see FIG. 5) in which the following through hole is formed on the side surface is used. In the same manner as in Example 1, a hollow fiber membrane module according to Example 8 was produced. The flow straightening cylinder used in this example has the following shape.
Inner diameter / outer diameter of the base end: 142 mm / 147 mm,
Inner diameter / outer diameter of tip portion: 154 mm / 158 mm,
Length: 85mm,
Through hole:
First line: width 50 mm, height 4 mm, center position is 55 mm from the base end, 5 pieces,
Second line: width 50 mm, height 6 mm, center position is 65 mm from the base end, and width 25 mm, height 6 mm, center position is 65 mm from the base end, 2 pieces,
Third line: width 50 mm, height 8 mm, the center position is 77 mm from the base end, and five through-holes are arranged in a staggered manner from the first line to the eighth line.
In the first to third lines, do not provide holes in the range of 45 ° to the left and right with respect to the central axis of the rectifying cylinder, and have through holes in the range of 45 ° to the left and right with respect to the central axis of the nozzle. The rectifying cylinder was placed in the cylindrical case so that it did not exist.

The total opening area of the through holes is 1000, 1500, and 2000 mm ² from the side closest to the base end of the flow straightening tube (first row) to the far side (third row), respectively. The through hole is larger on the side farthest than the side closest to the base end.

In addition, the hollow fiber membrane module of the present example has a flow path cross-sectional area ratio S ₂ / S ₁ of 0.31, and the weight is 34 kg in a state where the internal water has dripped completely, and it can be carried alone. It was.

(Measurement of module water permeability)
A filtration device was configured using the hollow fiber membrane module of this example, and the module water permeability was measured in the same manner as in Example 1.

The hollow fiber membrane module of this example had a module water permeability of 28 m ³ /hr/0.1 MPa @ 25 ° C. From this value and the module size, apparent volume reference of the module water permeability 1050m ^{3 /hr/0.1MPa/m 3} @ 25 ℃, module water permeability of the filtration unit volume basis is 1620m ³ /hr/0.1MPa/m ³ Calculated as @ 25 ° C. Also in this example, the value of Q _a / Q _b was approximately 1.0 as in Example 1, and almost the same amount of filtered water was flowing out from the upper and lower nozzles.

(Leak test)
Further, water was continuously passed for 3 months in the same manner as in Example 7 and a leak test was performed. As a result, there was no leak even after 3 months.

[Example 9]
In the same manner as in Example 1, two hollow fiber membrane modules according to Example 9 were produced. Using this hollow fiber membrane module, a leak test was conducted in the same manner as in Example 7 except that the filtrate flow rate was changed.

When the produced single module was used to pass water at a filtrate flow rate of 36 m ³ / h, three hollow fiber membranes leaked after one month. Further, when water was passed at a filtrate flow rate of 24 m ³ / h using the other one, there was no leakage even after 3 months.

When the leaked hollow fiber membrane module was disassembled and observed, the hollow fiber membrane on the outermost periphery of the membrane bundle was broken at the site where it contacted the tip of the rectifying cylinder. In addition, the other hollow fiber membranes on the outermost periphery were slightly damaged and not broken. Furthermore, when the hollow fiber membrane module subjected to the water flow test at 24 m ³ / h was disassembled and observed after the water flow test, the hollow fiber membrane was not damaged as observed in the leaked module.

[Reference Example 1]
A hollow fiber membrane module according to Reference Example 1 was produced in the same manner as Example 1. Using this hollow fiber membrane module, an apparatus having the same configuration as the external pressure filtration apparatus shown in FIG. 6 was constructed. A rotor type flow meter was provided on the downstream side of the valve V7 of the pipe L7 for discharging the concentrated water and on the downstream side of the valve V6 of the filtered water discharge pipe L6. In addition, an ultrasonic flow meter was provided at a position before the filtered water discharge pipe L6b joined to the upper pipe L6a so that the flow rate of water discharged from the lower side through the pipe L6b could be measured. The inner diameters of the pipes L6a and L6b are 51 mm.

Water flow is started by adjusting the opening of the valves V5 and V7 so that the flow rate of pure water at 25 ° C is 10 m ³ / hr and the amount of concentrated water is 0.3 m ³ / hr in the hollow fiber membrane module. The inside of the module was replaced with pure water. Subsequently, water was continuously passed for 3 months under the conditions of a filtrate water flow rate of 24 m ³ / hr and a concentrated water amount of 0.3 m ³ / hr. In addition, the valve V6 was fully opened at the time of water flow. The module was removed from the device every month, and a leak test was performed in the same manner as in Example 7. When there was no leak until 2 months later, 3 hollow fiber membranes leaked after 3 months. It was. In the case of the above-mentioned internal pressure type filtration, vibration of the hollow fiber membrane was not observed even when water was passed at a filtrate water flow rate of 36 m ³ / h. Vibrating vigorously was observed.

  When the hollow fiber membrane module was disassembled and the leak position was observed, the hollow fiber membrane in the outermost peripheral portion of the yarn bundle was broken near the lower fixed portion interface.

  The results of Examples 7 to 9 and Reference Example 1 are shown in Table 2.

  According to the hollow fiber membrane module of the present invention and the filtration method using the same, the flow rate of filtrate water flowing out from the nozzles at both ends can be made substantially equal without using a flow rate adjusting means such as a valve or an orifice, It is possible to sufficiently suppress the growth of microorganisms in the module and in the filtered water piping, and to stably obtain a large amount of water with good water quality. Since the hollow fiber membrane module of this invention can be made into a compact size, it is particularly suitable as a security filter for use in ultrapure water production facilities. The hollow fiber membrane module is also suitable as a pyrogen removal filter for use in water for injection production facilities.

  DESCRIPTION OF SYMBOLS 1 ... Yarn bundle, 1a ... Hollow fiber membrane, 1b ... Small bundle, 2 ... Cylindrical case, 2a, 2b ... Nozzle, 3a, 3b ... Fixed part, 4, 5 ... Rectification cylinder, 4a, 5a ... Base of rectification cylinder End part, 4b, 5b ... The tip part of a rectification cylinder, 4c ... Through-hole, 10, 20 ... Hollow fiber membrane module, 14 ... The rectification cylinder, 14a ... The base end part of a rectification cylinder, 14b ... The tip part of a rectification cylinder, 14c ... through hole, 100, 200 ... filtering device, Fa, Fb ... interface of the fixed part.

Claims (16)

A yarn bundle composed of a number of hollow fiber membranes;
A cylindrical case containing the yarn bundle and having a plurality of nozzles on the side surface;
At both ends of the yarn bundle in the cylindrical case, a pair of fixing portions sealing the outer surfaces of the hollow fiber membranes and the gap between the outer surface and the inner surface of the cylindrical case,
A hollow fiber membrane module Ru provided with,
A flow path sectional area ratio _{S 2} of the nozzle with respect to the hollow fiber membrane outside of the flow path cross-sectional area _{S 1} in the tubular inner case _(S 2 / _{S 1)} is state, and are 0.15 to 0.60,
The module further includes a pair of flow straightening tubes whose one ends are sealed by the fixing portion and extend so as to surround both end portions of the yarn bundle,
The pair of rectifying cylinders each have an opening through which the water inside the rectifying cylinder can circulate to the nozzle at a position isolated from the fixing portion.
At least one of the pair of rectifying cylinders has a plurality of through holes penetrating from the outer surface to the inner surface of the rectifying cylinder at a position spaced from the fixed portion, respectively.
The rectifying cylinder divides the entire region where the through hole is present into two equal parts, a first region closer to the fixing portion and a second region farther from the fixing portion. The hollow fiber membrane module whose aperture ratio by the said through hole in 2 area | region is higher than the aperture ratio by the said through hole in said 1st area | region .   The hollow fiber membrane module according to claim 1, wherein the cross-sectional areas of the plurality of nozzles are substantially the same.   The yarn bundle is formed by bundling a plurality of small bundles formed by bundling a plurality of hollow fiber membranes in the cylindrical case in parallel, and at least at the interface position of the fixed portion compared with other portions. The hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane module has a portion with a low packing density. The hollow fiber membrane module according to any one of claims 1 to 3 , wherein a module water permeability performance based on a filtration part volume at 25 ° C is 1000 to 3000 m ³ /hr/0.1 MPa / m ³ . The hollow fiber membrane module of Claim 4 whose water permeation amount per module in 25 degreeC is 20-40 m < ³ > /hr/0.1MPa. A yarn bundle composed of a number of hollow fiber membranes;
A cylindrical case containing the yarn bundle and having a plurality of nozzles on the side surface;
At both ends of the yarn bundle in the cylindrical case, a pair of fixing portions sealing the outer surfaces of the hollow fiber membranes and the gap between the outer surface and the inner surface of the cylindrical case,
With
A hollow fiber in which a ratio (S ₂ / S ₁ ) of a flow path cross-sectional area S ₂ of the nozzle to a flow cross-sectional area S ₁ outside the hollow fiber membrane in the cylindrical case is 0.15 or more and 0.60 or less. When performing filtration using a membrane module,
Supplying water to be treated from one end of the hollow fiber membrane module to the hollow portion of the hollow fiber membrane,
A filtration method in which filtered water that has flowed out of the hollow fiber membrane flows out from the nozzles at both ends of the cylindrical case through a pipe connected to the nozzle and is collected. The filtration method according to claim 6 , wherein the filtered water discharged from the nozzles at both ends is collected by being collected at a position nearer to a nozzle farther than a nozzle closer to the one end. The filtration method according to claim 6 or 7 , wherein flow path cross-sectional areas of the nozzles at both ends are substantially the same. The filtration method according to any one of claims 6 to 8 , wherein the pipe has an inner diameter 0.80 to 1.20 times larger than an inner diameter of the nozzle. The yarn bundle is formed by bundling a plurality of small bundles formed by bundling a plurality of hollow fiber membranes in the cylindrical case in parallel, and at least at the interface position of the fixed portion compared with other portions. the packing density of the hollow fiber membrane Te has a low portion, the method of filtration according to any one of claims 6-9. The module further includes a pair of flow tube extending so as to surround each of the both end portions of the front Symbol fiber bundle is sealed by one end the fixing unit,
The filtration method according to any one of claims 6 to 10 , wherein the pair of rectifying cylinders each have an opening through which water inside the rectifying cylinder can flow to the nozzle at a position isolated from the fixing portion. The filtration method according to claim 11 , wherein at least one of the pair of rectifying cylinders has a plurality of through holes penetrating from an outer surface to an inner surface of the rectifying cylinder at a position separated from the fixed portion. The rectifying cylinder divides the entire region where the through hole is present into two equal parts, a first region closer to the fixing portion and a second region farther from the fixing portion. The filtration method according to claim 12 , wherein an aperture ratio due to the through hole in the region of 2 is higher than an aperture ratio due to the through hole in the first region. The filtration method according to any one of claims 6 to 13 , wherein a module water permeability performance based on a filtration part volume at 25 ° C is 1000 to 3000 m ³ /hr/0.1 MPa / m ³ . The filtration method according to claim 14 , wherein the water permeability per module at 25 ° C. is 20 to 40 m ³ /hr/0.1 MPa. In an ultrapure water production system including at least ultraviolet irradiation means, ion exchange treatment means, and ultramembrane filtration treatment means,
The ultrapure water production system, wherein the ultramembrane filtration means is the hollow fiber membrane module according to any one of claims 1 to 5 .

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