JPH04317729A - Composite filtration membrane - Google Patents
Composite filtration membraneInfo
- Publication number
- JPH04317729A JPH04317729A JP8693591A JP8693591A JPH04317729A JP H04317729 A JPH04317729 A JP H04317729A JP 8693591 A JP8693591 A JP 8693591A JP 8693591 A JP8693591 A JP 8693591A JP H04317729 A JPH04317729 A JP H04317729A
- Authority
- JP
- Japan
- Prior art keywords
- membrane
- filtration
- filtration membrane
- nonwoven fabric
- composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 187
- 238000001914 filtration Methods 0.000 title claims abstract description 180
- 239000002131 composite material Substances 0.000 title claims abstract description 38
- 239000004745 nonwoven fabric Substances 0.000 claims abstract description 55
- 238000011001 backwashing Methods 0.000 claims abstract description 38
- 239000000126 substance Substances 0.000 claims abstract description 16
- 239000003365 glass fiber Substances 0.000 claims abstract description 13
- 239000002759 woven fabric Substances 0.000 claims abstract description 13
- 239000007787 solid Substances 0.000 claims description 48
- 239000012530 fluid Substances 0.000 claims description 41
- 239000011148 porous material Substances 0.000 claims description 34
- 239000007788 liquid Substances 0.000 claims description 23
- 239000000835 fiber Substances 0.000 claims description 18
- 238000001471 micro-filtration Methods 0.000 claims description 16
- 239000011550 stock solution Substances 0.000 claims description 15
- 239000012466 permeate Substances 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 13
- 238000000926 separation method Methods 0.000 abstract description 11
- 238000011084 recovery Methods 0.000 abstract description 10
- 239000010419 fine particle Substances 0.000 abstract description 9
- 240000004808 Saccharomyces cerevisiae Species 0.000 abstract description 4
- 244000005700 microbiome Species 0.000 abstract description 4
- 238000000746 purification Methods 0.000 abstract description 4
- 239000008223 sterile water Substances 0.000 abstract description 4
- 230000001954 sterilising effect Effects 0.000 abstract description 2
- 238000004659 sterilization and disinfection Methods 0.000 abstract description 2
- 238000011110 re-filtration Methods 0.000 abstract 1
- 230000004907 flux Effects 0.000 description 29
- 238000000034 method Methods 0.000 description 14
- 238000009295 crossflow filtration Methods 0.000 description 12
- 230000000694 effects Effects 0.000 description 10
- 230000001580 bacterial effect Effects 0.000 description 9
- 230000007423 decrease Effects 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 6
- 239000000725 suspension Substances 0.000 description 6
- 238000000108 ultra-filtration Methods 0.000 description 6
- 102000004190 Enzymes Human genes 0.000 description 5
- 108090000790 Enzymes Proteins 0.000 description 5
- 238000000855 fermentation Methods 0.000 description 5
- 230000004151 fermentation Effects 0.000 description 5
- 241000894006 Bacteria Species 0.000 description 4
- 239000004743 Polypropylene Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- -1 polypropylene Polymers 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 238000013459 approach Methods 0.000 description 3
- 235000013405 beer Nutrition 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000010008 shearing Methods 0.000 description 3
- 239000013076 target substance Substances 0.000 description 3
- 239000005909 Kieselgur Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 229920002492 poly(sulfone) Polymers 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 239000011942 biocatalyst Substances 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 239000012531 culture fluid Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000000909 electrodialysis Methods 0.000 description 1
- 238000006911 enzymatic reaction Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000001963 growth medium Substances 0.000 description 1
- 230000003834 intracellular effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920005597 polymer membrane Polymers 0.000 description 1
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002683 reaction inhibitor Substances 0.000 description 1
- 239000004627 regenerated cellulose Substances 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、精密濾過膜に関するも
のであり、特に大きい膜透過流束を維持するために懸濁
物質の捕捉性が高く逆洗洗浄性のよい複合膜に関するも
のである。本発明の複合濾過膜は、種々の高分子、微生
物、酵母、微粒子を含有あるいは懸濁する流体の分離、
精製、回収、濃縮などに適用され、特に濾過を必要とす
る微細な微粒子を含有する流体からその微粒子を分離す
る必要のあるあらゆる場合に適用することができ、例え
ば微粒子を含有する各種の懸濁液、発酵液あるいは培養
液などの他、顔料の懸濁液などから微粒子を分離する、
原子力発電の復水からクラッドを分離除去する場合にも
適用される。ところで近年バイオテクノロジーの急速な
発展にともない、培養、発酵、酵素反応等による生化学
物質の生産は、医薬品・食品・化学製品など多くの分野
で盛んに行われるようになってきた。これらの生産物質
は精製することによって付加価値が高まるが、この精製
操作に多くのコストがかけられるのが現状である。本発
明のデッドエンド型濾過方法はこれらの分野で特に有効
であり、例えば培養液中から反応阻害物質を連続的に除
去することにより高密度培養を行う、菌体外酵素生産菌
を用いた時に酵素を連続回収する、菌体内酵素生産菌を
破砕した溶液から酵素を回収する、バッチ式で得られた
培養液から生体触媒を除去する、など多岐にわたって適
用される。[Industrial Application Field] The present invention relates to a precision filtration membrane, and particularly to a composite membrane that has a high ability to trap suspended solids and has good backwashing ability in order to maintain a large membrane permeation flux. . The composite filtration membrane of the present invention can be used to separate fluids containing or suspending various polymers, microorganisms, yeast, and fine particles.
It can be applied in purification, recovery, concentration, etc., and in particular in any case where it is necessary to separate fine particles from a fluid containing fine particles that requires filtration, such as in various suspensions containing fine particles. Separating fine particles from liquids, fermentation liquids, culture liquids, pigment suspensions, etc.
It is also applied when separating and removing crud from condensate in nuclear power generation. However, with the rapid development of biotechnology in recent years, the production of biochemical substances through cultivation, fermentation, enzymatic reactions, etc. has become popular in many fields such as pharmaceuticals, foods, and chemical products. Although the added value of these produced substances increases by refining them, the current situation is that a lot of cost is incurred in this refining operation. The dead-end filtration method of the present invention is particularly effective in these fields, for example, when using exoenzyme-producing bacteria that perform high-density culture by continuously removing reaction inhibitors from the culture solution. It has a wide variety of applications, including continuous recovery of enzymes, recovery of enzymes from a solution obtained by crushing intracellular enzyme-producing bacteria, and removal of biocatalysts from culture solutions obtained in a batch process.
【０００２】0002
【従来の技術】従来、膜を用いて懸濁物質を含有する原
液から懸濁物質を分離する技術としては、例えば圧力を
駆動力とする逆浸透法、限外濾過法、精密濾過法、電位
差を駆動力とする電気透析法、濃度差を駆動力とする拡
散透析法等がある。これらの方法は、連続操作が可能で
あり、分離操作中に温度やｐＨの条件を大きく変化させ
ることなく分離、精製あるいは濃縮ができ、粒子、分子
、イオン等の広範囲にわたって分離が可能であり、小型
プラント処理能力を大きく保つことができるので経済的
であり、分離操作に要するエネルギーが小さく、かつ他
の分離方法では難しい低濃度原流体の処理が可能である
などの理由により広範囲に実施されている。そしてこれ
らの分離技術に用いられる膜としては、酢酸セルロース
、硝酸セルロース、再生セルロース、ポリスルホン、ポ
リアクリロニトリル、ポリアミド、ポリイミド等の有機
高分子等を主体とした高分子膜や耐熱性、耐薬品性など
の耐久性に優れている多孔質セラミック膜などがあり、
主としてコロイドの濾過を対象とする場合は限外濾過膜
が使用され、微細な粒子の濾過を対象とする精密濾過で
はそれに適した微孔を有する精密濾過膜が使用されてい
る。前述したようにバイオテクノロジーの進歩に伴い、
高純度化、高性能化、高精密化が要求されるようになり
、従来から行われている遠心分離やけい藻土濾過に代わ
って連続操作が可能で大量処理できる、濾過助剤や凝集
剤の添加が必要ない、分離の効率は菌体と懸濁液の比重
差に無関係であり培養液の物性や菌体の種類に関係なく
清澄な濾液が得られる、高濃度培養ができ生産効率が向
上する、完全密閉系が可能で菌の漏れがない、濃縮後菌
体の洗浄が可能である、スケールアップが容易で経済性
が高い等の理由で、精密濾過あるいは限外濾過技術の応
用分野が拡大しつつある。しかしながら、濾過膜の利点
が多いにもかかわらず精密濾過あるいは限外濾過膜を用
いて微粒子を分離する場合に、濃度分極の影響によりケ
ーク層が生じて透過流体の流れに抵抗が生じ、また濾過
膜の目詰まりによる抵抗が大きくなって膜透過流束が急
激にかつ著しく低下してしまうという問題があり、これ
が精密濾過あるいは限外濾過の実用化を妨げる最大の原
因であった。またそれに用いられる膜は汚染されやすく
、その防止対策が必要である。[Prior Art] Conventionally, techniques for separating suspended solids from a stock solution containing suspended solids using a membrane include, for example, reverse osmosis using pressure as a driving force, ultrafiltration, microfiltration, and potential difference There are electrodialysis methods that use the driving force as the driving force, and diffusion dialysis methods that use the concentration difference as the driving force. These methods can be operated continuously, can separate, purify, or concentrate without significantly changing temperature or pH conditions during the separation operation, and can separate a wide range of particles, molecules, ions, etc. It is economical because it can maintain a large processing capacity in a small plant, requires little energy for separation operations, and can process low-concentration raw fluids that are difficult to use with other separation methods, so it has been widely implemented. There is. The membranes used in these separation techniques include polymer membranes mainly made of organic polymers such as cellulose acetate, cellulose nitrate, regenerated cellulose, polysulfone, polyacrylonitrile, polyamide, and polyimide, as well as those with heat resistance, chemical resistance, etc. There are porous ceramic membranes with excellent durability.
Ultrafiltration membranes are used when the purpose is mainly to filter colloids, and precision filtration membranes with suitable micropores are used for precision filtration to filter fine particles. As mentioned above, with the progress of biotechnology,
As higher purity, higher performance, and higher precision are required, filter aids and flocculants that can be operated continuously and can be processed in large quantities replace conventional centrifugation and diatomaceous earth filtration. The separation efficiency is unrelated to the difference in specific gravity between the bacterial cells and the suspension, and a clear filtrate can be obtained regardless of the physical properties of the culture medium or the type of bacterial cells.High concentration cultivation is possible and production efficiency is high. The field of application of precision filtration or ultrafiltration technology is increasing due to the following reasons: it is possible to create a completely sealed system and there is no leakage of bacteria, it is possible to wash the bacteria after concentration, it is easy to scale up and it is highly economical, etc. is expanding. However, despite the many advantages of filtration membranes, when microparticles are separated using microfiltration or ultrafiltration membranes, a cake layer is generated due to the influence of concentration polarization, which creates resistance to the flow of the permeate fluid. There is a problem in that the resistance due to membrane clogging increases and the membrane permeation flux rapidly and significantly decreases, and this has been the biggest cause of hindering the practical application of precision filtration or ultrafiltration. Furthermore, the membrane used therein is easily contaminated, and measures to prevent this are required.
【０００３】濾過方法としては、濾過されるべき全ての
流体が濾材（濾布や膜など）とケーク層を通過して流体
中に含まれている微粒子を分離するいわゆるデッドエン
ド型濾過方式がある。この従来のデッドエンド型濾過方
式では流体が通過して懸濁物質が濾過膜の内部に捕捉さ
れて分離される段階では高い透過流束が得られるが、濾
過膜の表面で捕捉される段階になるとケーク層が形成さ
れ、大量の原流体を処理する場合や形成されるケーク層
の比抵抗が極端に高い場合は大きな濾過抵抗となり、こ
のようなデッドエンド濾過を行うと膜透過流束が小さく
なる。このため、クロスフロー型濾過方式が考えられた
。このクロスフロー型濾過方式は、濾過膜の膜表面に平
行に濾過すべき原流体を流し、流体は濾過膜を通って反
対側へ透過し、この原流体と透過流体の流れが直交して
いるためにこのように称されている。このクロスフロー
型濾過方法は、濾過膜に平行な原流体の流れによって膜
面上に形成されたケーク層がはぎ取られるので従来のデ
ッドエンド型濾過方式に比べて膜透過流束が大きく、大
量の原流体を直接連続的に分離、精製、濃縮が可能であ
る。しかし懸濁物質の濾過比抵抗が極端に高い、すなわ
ち培養液、発酵液から菌体や高分子生成物を除くために
純水透過流束の大きいすなわち分画分子量の大きい限外
濾過膜や精密濾過膜を用いた場合は急激に膜透過流束が
低下して濾過開始初期の高い膜透過流束を保つことは困
難であり、結果としてデッドエンド型濾過方式と総透過
液量を比較すると効果は小さく経済的な透過流束を得る
には不十分であった。[0003] As a filtration method, there is a so-called dead-end filtration method in which all the fluid to be filtered passes through a filter medium (filter cloth, membrane, etc.) and a cake layer to separate fine particles contained in the fluid. . In this conventional dead-end filtration system, a high permeation flux is obtained when the fluid passes through and the suspended solids are trapped inside the filtration membrane and separated, but when the suspended solids are trapped on the surface of the filtration membrane, When a large amount of raw fluid is processed or when the specific resistance of the formed cake layer is extremely high, the filtration resistance becomes large, and when such dead-end filtration is performed, the membrane permeation flux is small. Become. For this reason, a cross-flow type filtration system was considered. In this cross-flow filtration system, the raw fluid to be filtered is passed parallel to the membrane surface of the filtration membrane, the fluid passes through the filtration membrane to the opposite side, and the flow of the raw fluid and the permeated fluid are perpendicular to each other. This is why it is called this way. In this cross-flow filtration method, the cake layer formed on the membrane surface is stripped off by the flow of the raw fluid parallel to the filtration membrane, so the membrane permeation flux is larger than in the conventional dead-end filtration method, and a large amount of It is possible to directly and continuously separate, purify, and concentrate raw fluids. However, in order to remove microbial cells and polymer products from culture fluids and fermentation fluids, which have extremely high filtration specific resistance for suspended solids, ultrafiltration membranes with high pure water permeation flux, or high molecular weight cutoff, and precision filters are used. When using a filtration membrane, the membrane permeation flux decreases rapidly and it is difficult to maintain a high membrane permeation flux at the beginning of filtration.As a result, when comparing the dead-end filtration method and the total permeate volume, was small and insufficient to obtain an economical permeation flux.
【０００４】0004
【発明が解決しようとする課題】上述のように、クロス
フロー型濾過方式は原理的には高度な分離技術であるが
、最大の問題である膜透過流束は、従来のデッドエンド
型濾過方式に僅かに大きい程度で、精密濾過方法として
このクロスフロー方式を採用しても十分高い膜透過流束
が得られないという問題があった。また従来から行われ
ている懸濁物質と流体との分離の具体的な例を見ても、
例えば発酵液から菌体を分離する場合には、従来から行
われている遠心分離法、珪藻土濾過法などに代わってク
ロスフロー濾過方式を用いても膜面上に形成されたケー
ク層や目詰まりによって濾過時間の経過と共に膜透過流
束が低下するばかりでなく、原流体を循環する際の剪断
力によって菌体の活性が失われるという問題があった。[Problems to be Solved by the Invention] As mentioned above, the cross-flow filtration system is an advanced separation technology in principle, but the biggest problem, the membrane permeation flux, is lower than that of the conventional dead-end filtration system. However, even if this cross-flow method is adopted as a precision filtration method, a sufficiently high membrane permeation flux cannot be obtained. Also, looking at specific examples of conventional separation of suspended solids and fluids,
For example, when separating bacterial cells from a fermentation liquid, even if a cross-flow filtration method is used instead of the conventional centrifugation method or diatomaceous earth filtration method, a cake layer or clogging may occur on the membrane surface. Therefore, there is a problem that not only the membrane permeation flux decreases as the filtration time passes, but also the activity of the bacterial cells is lost due to the shear force when circulating the raw fluid.
【０００５】透過流束を高める方法としては従来より濾
過膜への原流体の流入を断続的に停止したり、濾過膜の
透過流体側の弁を閉止することにより、濾過膜の膜面に
垂直にかかる圧力を断続的になくすあるいは減少させた
り、また濾過膜の透過液側から圧力を加え透過液側から
原流体側へ流体を流すことによって、濾過膜の原流体側
の膜面上に堆積しているケーク層や付着層を断続的に取
り除く「逆洗」と称する試みがなされているが、懸濁物
質の濾過比抵抗が小さい場合は逆洗により濾過膜に堆積
した懸濁物質は容易に脱着できるが、懸濁物質の濾過比
抵抗が高く濾過膜との付着力の強い高分子成分や菌体の
場合は、逆洗を行っても濾過膜から十分取り除くことが
できず膜透過流速が十分回復しないなどの問題点があっ
た。またこれら逆洗を行った際に濾過膜から脱着した懸
濁物質を濾過系内に残しておくと原流体中の懸濁物の濃
度が徐々に増加し、場合によっては原流体の粘度も上昇
するため膜透過流束は徐々に低下して逆洗を行っても透
過流束が十分回復しない等の問題があった。一方菌体の
活性を低下させない方法として、クロスフロー濾過の場
合は循環流速を低下させ剪断力を小さくすることが行わ
れているが、剪断力を小さくするとクロスフロー濾過方
式の効果が小さくなるため、実際に菌体活性を低下させ
ない方策をとると膜透過流束が低下する問題があった。
またポンプでの菌体の破砕を少なくするためダイヤフラ
ムポンプなどの剪断力の小さいポンプを用いるとポンプ
の脈動が大きくクロスフロー濾過方式の効果が小さくな
る等の問題もあった。Conventional methods for increasing permeation flux include intermittently stopping the flow of raw fluid into the filtration membrane, or closing the valve on the permeate side of the filtration membrane. By intermittently eliminating or reducing the pressure applied to the filtration membrane, or by applying pressure from the permeate side of the filtration membrane and flowing fluid from the permeate side to the raw fluid side, deposits can be removed on the membrane surface on the raw fluid side of the filtration membrane. Attempts have been made to intermittently remove the cake layer and adhering layer, but if the filtration specific resistance of suspended solids is small, backwashing can easily remove suspended solids that have accumulated on the filtration membrane. However, in the case of polymeric components and bacterial cells that have a high filtration specific resistance of suspended solids and strong adhesion to the filtration membrane, they cannot be sufficiently removed from the filtration membrane even if backwashing is performed, and the membrane permeation flow rate decreases. There were problems such as insufficient recovery. In addition, if the suspended solids desorbed from the filtration membrane during backwashing are left in the filtration system, the concentration of suspended solids in the raw fluid will gradually increase, and in some cases, the viscosity of the raw fluid will also increase. Therefore, there was a problem that the membrane permeation flux gradually decreased and the permeation flux did not recover sufficiently even if backwashing was performed. On the other hand, in the case of cross-flow filtration, the method of not reducing the activity of bacterial cells is to reduce the circulation flow rate and reduce the shearing force, but since reducing the shearing force reduces the effectiveness of the cross-flow filtration method. However, if measures were taken that did not actually reduce bacterial cell activity, there was a problem that the membrane permeation flux would decrease. Furthermore, when a pump with a small shearing force such as a diaphragm pump is used to reduce the crushing of bacterial cells by the pump, there is a problem that the pump pulsates so much that the effect of the cross-flow filtration system is reduced.
【０００６】[0006]
【課題を解決するための手段】本発明は、上述した従来
技術にあった問題点を解決するために為されたものであ
って、実用性のある高い膜透過流束を持ち菌体などの活
性低下を減少させる新規な濾過膜を提供することを目的
とするものである。 すなわち本発明は、精密濾過膜
を用いて、懸濁物質を含む流体からなる原液を供給し濾
過することにより流体と懸濁物質とを分離する濾過方式
において、濾過膜が精密濾過膜と不織布、織布またはガ
ラス繊維との積層複合膜であり、不織布、織布またはガ
ラス繊維が厚さ方向に多層構造をもつことにより達成さ
れる。 以下、本発明を詳細に説明する。本発明のデ
ッドエンド型濾過方法に用いる複合濾過膜は、種々の高
分子、微生物、酵母、微粒子を含有あるいは懸濁する流
体の分離、精製、回収、濃縮など、濾過を必要とする微
細な微粒子を含有する流体からその微粒子を分離する必
要のあるあらゆる場合に適用することができるが、特に
発酵液、培養液からの酵素、微生物、細胞の分離、濃縮
、回収など懸濁物質の濾過比抵抗が極端に大きい場合に
効果がある。[Means for Solving the Problems] The present invention has been made to solve the problems of the prior art described above, and has a practical high membrane permeation flux, and is capable of transporting bacterial cells, etc. The object of the present invention is to provide a novel filtration membrane that reduces the decrease in activity. That is, the present invention provides a filtration method that uses a precision filtration membrane to separate a fluid and suspended matter by supplying and filtering a stock solution consisting of a fluid containing suspended matter, in which the filtration membrane is a precision filtration membrane, a nonwoven fabric, It is a laminated composite membrane with woven fabric or glass fiber, and is achieved by having a multilayer structure in the thickness direction of the nonwoven fabric, woven fabric, or glass fiber. The present invention will be explained in detail below. The composite filtration membrane used in the dead-end filtration method of the present invention is used to remove fine particles that require filtration, such as separation, purification, recovery, and concentration of fluids containing or suspending various polymers, microorganisms, yeast, and particles. It can be applied in any case where it is necessary to separate its particulates from fluids containing them, but especially in the separation, concentration, recovery of enzymes, microorganisms, cells from fermentation liquids, culture liquids, etc. Specific resistance filtration of suspended solids This is effective when is extremely large.
【０００７】本発明の濾過方式で使用される濾過膜は懸
濁物質が阻止できる孔径を持つものが必要であり、精密
濾過膜では通常０．０５〜１０μｍの孔径を有するもの
が使用される。これら精密濾過膜を０．５分から３分の
短い時間で濾過した場合の総濾過量は、濾過膜の構造に
著しく影響を受ける。濾過膜の種類として、その内部に
存在する微孔の孔径が実質的に変化せず、膜の両表面の
孔径が実質的に変わらない所謂等方性膜と、膜厚方向に
孔径が連続的または不連続的に変化し、膜の一方の表面
の孔径と他方の表面の孔径とが異なっている所謂異方性
膜と呼ばれる構造を有するものとに分類される。これら
のうち等方性膜は、特開昭５８−９８０１５号に記載さ
れているが、濾過にあたって膜全体が流体の流れに対し
て大きな抵抗を示し、小さな流速しか得られない（即ち
、単位面積当り、単位時間当り、単位差圧当り小さな流
量しか得られない）上、目詰まりがしやすく濾過寿命が
短い、耐ブロッキング性がない等の欠点があった。一方
異方性膜は特公昭５５−６４０６、特開昭５６−１５４
０５１号、特開昭６３−１３９９３０に記載されている
如く緻密層と呼ばれている孔径の小さな層を膜の片方の
表面、または膜の内部に持ち、比較的大きな孔をあるい
は極端に大きなボイドを膜の内部からもう一方の表面に
かけて持ったものである。懸濁物質は等方性膜を用いる
かまたは異方性膜の孔径の小さい側に原流体を供給する
場合は濾過膜表面で捕捉され、一方異方性膜の孔径の大
きい側に原流体を供給する場合は懸濁物質は濾過膜の内
部で捕捉される。すなわち懸濁物質を濾過膜の表面で阻
止する場合は阻止された懸濁物質が非常に大きな濾過抵
抗となって透過流束が急激に低下し結果として総濾過量
は低くなるが、濾過膜が膜厚方向に孔径が連続的または
不連続的に変化し濾過膜の一方の表面の孔径と他方の表
面の孔径とが異なる構造を有するいわゆる異方性膜を表
面孔径の大きい側を原流体側に向けて使用することによ
り、濾過膜内部で懸濁物質が阻止できるため大きな総濾
過量を得ることが可能となる。The filtration membrane used in the filtration method of the present invention must have a pore size that can block suspended solids, and precision filtration membranes usually have a pore size of 0.05 to 10 μm. The total filtration amount when these microfiltration membranes are used for filtration in a short time of 0.5 to 3 minutes is significantly influenced by the structure of the filtration membrane. There are two types of filtration membranes: so-called isotropic membranes, in which the pore diameters of the micropores existing inside the membrane do not substantially change, and pore diameters on both surfaces of the membrane do not substantially change, and pore diameters that are continuous in the membrane thickness direction. Alternatively, it is classified as having a structure called an anisotropic membrane, in which the pore size on one surface of the membrane is different from the pore size on the other surface. Among these, isotropic membranes are described in JP-A No. 58-98015, but during filtration, the entire membrane exhibits a large resistance to the flow of fluid, and only a small flow rate can be obtained (i.e., (only a small flow rate can be obtained per unit time, per unit time, and per unit pressure difference), and it also has drawbacks such as easy clogging, short filtration life, and lack of blocking resistance. On the other hand, the anisotropic film is
As described in No. 051, JP-A No. 63-139930, the membrane has a layer with a small pore size called a dense layer on one surface of the membrane or inside the membrane, and has relatively large pores or extremely large voids. from the inside of the membrane to the other surface. Suspended solids are trapped on the filtration membrane surface when an isotropic membrane is used or when the raw fluid is supplied to the smaller pore side of the anisotropic membrane, whereas when the raw fluid is supplied to the larger pore side of the anisotropic membrane. When fed, suspended solids are trapped inside the filter membrane. In other words, when suspended solids are blocked on the surface of a filtration membrane, the blocked suspended solids create a very large filtration resistance and the permeation flux decreases rapidly, resulting in a lower total filtration rate. A so-called anisotropic membrane has a structure in which the pore diameter changes continuously or discontinuously in the membrane thickness direction, and the pore diameter on one surface of the filtration membrane is different from the pore diameter on the other surface.The side with the larger surface pore diameter is the raw fluid side. By using it for this purpose, suspended solids can be blocked inside the filtration membrane, making it possible to obtain a large total filtration amount.
【０００８】本発明の複合濾過膜は、精密濾過膜と不織
布、織布またはガラス繊維を一体化した複合構造であり
、不織布等側を原液側にすることによりさらに懸濁物質
の捕捉性および逆洗による洗浄性が高まる。特に、懸濁
物質の粒径分布が広い場合は大きい懸濁物質は不織布内
部に、小さい懸濁物質は多孔質濾過膜内部に捕捉される
ため効果は大きい。これら不織布、織布またはガラス繊
維はそれらを形成する繊維の太さ、空隙率、厚みによっ
て懸濁物質の阻止性能が異なる。すなわち繊維の太さが
細く、空隙率が低くなるほど細かい懸濁物質を阻止し、
また厚みが厚くなるほど多量の懸濁物質を阻止できる。
ここで示す膜表面および膜内部の平均孔径は電子顕微鏡
で得られた写真から算出した。精密濾過膜と不織布、織
布、ガラス繊維を一体化した複合濾過膜はそれ自身で充
分高い懸濁物質捕捉性能と逆洗洗浄性を示すが、不織布
等を多層構造とすることによりさらに効果は高まる。す
なわち懸濁物質の濃度が非常に高く、粒径分布が広い場
合は不織布等が異方性構造を持つことにより不織布等の
内部で懸濁物質が分散して捕捉されるため総濾過量は増
大し、また逆洗等を行なったときの洗浄効果も高まる。
不織布等の構造については特に繊維の太さが懸濁物質の
阻止性能と密接な相関があり、原液側から繊維太さを連
続的または段階的に細くすることによって不織布等の異
方性構造が得られる。本発明では複合濾過膜の不織布等
の側を原液側にして用いるため、原液側の不織布等の繊
維太さが最も太く精密濾過膜に近づくにつれて繊維の太
さは細くすることが好ましい。精密濾過膜と接する側の
不織布等の繊維太さは精密濾過膜の表面孔径と相関があ
る。すなわち不織布等の実質的な孔径が不織布等が接す
る精密濾過膜の表面孔径とほぼ同じか若干大きいことが
好ましい。精密濾過膜と不織布の界面で孔径がほぼ連続
的となるための不織布等の繊維の太さは濾過膜表面孔径
の０．５倍以上５倍以下である。すなわち濾過膜表面の
平均孔径が２μｍの場合、不織布等の繊維太さは１μｍ
以上５μｍ以下であることが好ましい。一方、原液側の
不織布等の繊維太さは、濾過膜に接する不織布等の繊維
太さの１倍以上１０倍以下、好ましくは２倍以上５倍以
下であることが好ましい。不織布等の空隙率は極端に低
くすると濾過抵抗が大きくなり、逆に高すぎると懸濁物
質を阻止しなくなるため、通常は５０％以上９０％以下
が好ましく、さらに６０％以上７５％以下が好ましい。
また不織布等の厚みが薄いと懸濁物質の捕捉効果は得ら
れず、精密濾過膜の厚みの１／２以上であることが好ま
しい。不織布等の材質は特に限定されるものではないが
、一般的にポリエステル、ポリプロピレン、ポリアミド
、ステンレスなどが用いられる。また、周期的に逆洗を
行う場合は、逆洗時に濾過膜に対して大きな負荷がかか
り濾過膜強度が弱いときは濾過膜に亀裂が生じるなどの
問題がおこったが、濾過膜を不織布等と一体化すること
により濾過膜強度を極端に上昇させることが可能となる
。濾過膜と不織布等とを一体化する方法は、点状または
線状に接着剤で行うかヒートシールで溶融接着を行って
もよいが、特公昭４５−１３９３１のごとく濾過膜を製
膜する際に製膜原液を直接不織布等にキャスティングし
て濾過膜が不織布等に一部侵入した状態で多孔質構造を
形成してもよい。The composite filtration membrane of the present invention has a composite structure in which a precision filtration membrane and a nonwoven fabric, a woven fabric, or a glass fiber are integrated. Improves cleaning performance by washing. In particular, when the particle size distribution of the suspended solids is wide, the effect is great because large suspended solids are trapped inside the nonwoven fabric and small suspended solids are trapped inside the porous filtration membrane. These nonwoven fabrics, woven fabrics, or glass fibers have different suspended solid blocking performance depending on the thickness, porosity, and thickness of the fibers forming them. In other words, the thinner the fiber thickness and the lower the porosity, the more fine suspended solids are blocked.
Also, the thicker the layer, the more suspended solids can be blocked. The average pore diameters on the membrane surface and inside the membrane shown here were calculated from photographs taken with an electron microscope. Composite filtration membranes that integrate precision filtration membranes with nonwoven fabrics, woven fabrics, and glass fibers exhibit sufficiently high suspended solids capture performance and backwashing properties on their own, but they can be even more effective by using a multilayer structure of nonwoven fabrics, etc. It increases. In other words, when the concentration of suspended solids is very high and the particle size distribution is wide, the nonwoven fabric has an anisotropic structure, so the suspended solids are dispersed and captured inside the nonwoven fabric, so the total filtration rate increases. Furthermore, the cleaning effect when performing backwashing etc. is also enhanced. Regarding the structure of non-woven fabrics, etc., the thickness of the fibers is particularly closely correlated with the ability to block suspended solids, and by thinning the fiber thickness continuously or stepwise from the raw solution side, anisotropic structures such as non-woven fabrics can be created. can get. In the present invention, since the nonwoven fabric side of the composite filtration membrane is used as the stock solution side, it is preferable that the fiber thickness of the nonwoven fabric etc. on the stock solution side is the thickest and becomes thinner as it approaches the precision filtration membrane. The thickness of the fibers of the nonwoven fabric or the like on the side in contact with the microfiltration membrane has a correlation with the surface pore size of the microfiltration membrane. That is, it is preferable that the substantial pore diameter of the nonwoven fabric or the like is approximately the same as or slightly larger than the surface pore diameter of the microfiltration membrane with which the nonwoven fabric or the like is in contact. The thickness of the fibers such as the nonwoven fabric is 0.5 times or more and 5 times or less the pore size on the surface of the filtration membrane so that the pore size becomes almost continuous at the interface between the precision filtration membrane and the nonwoven fabric. In other words, if the average pore diameter on the surface of the filtration membrane is 2 μm, the fiber thickness of nonwoven fabric etc. is 1 μm.
It is preferable that the thickness is 5 μm or less. On the other hand, it is preferable that the thickness of the fibers of the nonwoven fabric, etc. on the side of the undiluted solution is 1 to 10 times, preferably 2 to 5 times, the thickness of the fibers of the nonwoven fabric, etc. in contact with the filtration membrane. If the porosity of the nonwoven fabric is extremely low, the filtration resistance will increase, and if it is too high, it will not block suspended solids, so it is usually preferably 50% or more and 90% or less, and more preferably 60% or more and 75% or less. . Further, if the thickness of the nonwoven fabric is too small, the effect of trapping suspended substances cannot be obtained, so it is preferable that the thickness is 1/2 or more of the thickness of the microfiltration membrane. Although the material of the nonwoven fabric is not particularly limited, polyester, polypropylene, polyamide, stainless steel, etc. are generally used. In addition, when backwashing is performed periodically, there are problems such as a large load on the filtration membrane during backwashing and cracks in the filtration membrane when the strength of the filtration membrane is weak. By integrating with the filtration membrane, it becomes possible to dramatically increase the strength of the filtration membrane. The method of integrating the filtration membrane and the nonwoven fabric, etc. may be done by adhesive in dots or lines, or by melt bonding by heat sealing. Alternatively, a porous structure may be formed by directly casting the membrane-forming stock solution onto a nonwoven fabric or the like, with the filtration membrane partially penetrating the nonwoven fabric or the like.
【０００９】本発明のデッドエンド濾過で行う逆洗はガ
スよりも液体で行う方が効果が大きく、系外からの異物
混入を避ける場合は逆洗液として透過液を用いることが
できる。また透過液を逆流させた分だけ透過量が減少す
ることを避ける場合は、濾過系外より洗浄液を供給して
必要に応じた逆洗液量で逆洗を行うことが好ましい。濾
過系外より供給する洗浄液は濾過膜の特性を低下させた
り原流体の特性を変化させなければ基本的には何でも良
いが、原流体が水溶液である場合には一般的には滅菌水
を用いることが好ましい。また、逆洗終了後逆洗液を濾
過系内に残したくない場合はガスによる脱水を行うこと
が好ましい。 逆洗は膜透過流束が極端に低くなって
から行うと逆洗後の膜透過流束の回復性は悪くなる。こ
れは懸濁物質が濾過膜の内部に深く侵入したり堆積した
懸濁物質が圧密化したり、また長時間濾過を行うと懸濁
物質が濾過膜に強く結合するため、逆洗時に堆積した懸
濁物質を完全に取り除くことができなくなるためである
。
このため定圧濾過を行う場合は濾過初期の透過流速の１
／１００に達する前に逆洗を行うことが好ましく、さら
に高い透過流速を得るためには１／１０に達する前に逆
洗を行うことが好ましい。また、定速濾過を行う場合は
濾過膜間差圧が極端委高くなってから逆洗を行うと逆洗
後の濾過膜間差圧の回復性すなわち濾過膜の洗浄性が悪
くなるため、濾過初期の濾過膜間差圧の１００倍に達す
る前に逆洗を行うことが好ましく、さらに好ましくは１
０倍に達する前に逆洗を行う。従って濾過開始から逆洗
に至るまでの時間は短く、懸濁物質の比抵抗が大きい場
合は濾過を０．５分以上３分以内行った後に逆洗を行う
ことが好ましい。また、逆洗液は高い透過流速で多量に
濾過膜内を通過させる方が洗浄性は高くなるが、逆洗液
の透過流束を高めて長時間逆洗を行うことは逆洗液量が
膨大となるばかりでなく、濾過時間に対する逆洗時間の
比率が高まり事実上平均透過流束は低くなるため、十分
透過流束が回復できる範囲で透過流速は１×１０−４ｍ
３／ｍ２／ｓｅｃ以上であり、時間は１秒以上３０秒以
内であることが好ましい。Backwashing performed in the dead-end filtration of the present invention is more effective when carried out with a liquid than with a gas, and a permeated liquid can be used as the backwashing liquid if foreign matter contamination from outside the system is to be avoided. In addition, in order to avoid a decrease in the permeation amount by the amount of backflow of the permeate, it is preferable to supply a cleaning liquid from outside the filtration system and perform backwashing with an amount of backwash liquid as required. Basically, any cleaning liquid supplied from outside the filtration system may be used as long as it does not degrade the properties of the filtration membrane or change the properties of the raw fluid, but if the raw fluid is an aqueous solution, sterile water is generally used. It is preferable. Further, if it is desired not to leave the backwash liquid in the filtration system after the backwash is completed, it is preferable to perform dehydration using gas. If backwashing is performed after the membrane permeation flux becomes extremely low, the recovery of the membrane permeation flux after backwashing will deteriorate. This is due to suspended solids penetrating deeply into the filtration membrane, the accumulated suspended solids becoming compacted, or the suspended solids strongly bonding to the filtration membrane when filtration is performed for a long time. This is because the turbid substances cannot be completely removed. Therefore, when performing constant pressure filtration, 1 of the permeation flow rate at the initial stage of filtration
It is preferable to perform backwashing before reaching 1/100, and in order to obtain an even higher permeation flow rate, it is preferable to perform backwashing before reaching 1/10. In addition, when performing constant-speed filtration, if backwashing is performed after the pressure difference between the filtration membranes becomes extremely high, the recovery of the pressure difference between the filtration membranes after backwashing, that is, the cleaning performance of the filtration membranes, will deteriorate. It is preferable to carry out backwashing before the pressure difference between the filtration membranes reaches 100 times the initial pressure difference between the membranes, more preferably 1
Perform backwashing before reaching 0 times. Therefore, the time from the start of filtration to backwashing is short, and if the specific resistance of the suspended solids is large, it is preferable to perform backwashing after filtration is performed for 0.5 minutes or more and up to 3 minutes. In addition, cleaning performance will be higher if a large amount of backwash liquid is passed through the filtration membrane at a high permeation flow rate, but if the permeation flux of backwash liquid is increased and backwash is performed for a long time, Not only will the amount be enormous, but the ratio of backwashing time to filtration time will increase, effectively lowering the average permeation flux, so the permeation flow rate should be 1 x 10-4 m as long as the permeation flux can be recovered sufficiently.
3/m2/sec or more, and the time is preferably 1 second or more and 30 seconds or less.
【００１０】次に本発明の複合濾過膜を用いたデッドエ
ンド型濾過方式を図面に基づいて説明する。図１は従来
のデッドエンド型濾過を行った際に濾過膜に堆積する懸
濁物の様子を示しており、経時とともに堆積する懸濁物
質量は増加し、最終的には透過流束はゼロに近づく。
図２はクロスフロー濾過を行った際に濾過膜に堆積す
る懸濁物質の様子を示しており、濾過開始初期において
は懸濁物質が徐々に増加するが原流体の剪断力によって
堆積する懸濁物質量は一定値をとり透過流束も最終的に
は一定値に近づく。 図３は本発明のデッドエンド型
濾過方式のフローを示している。濾過を一定時間行った
後透過流体側から原流体側に滅菌水を流して濾過膜から
脱着した懸濁物質と共に排出する。その後ガスにより濾
過系内に残留している滅菌水を排出し、再び濾過を行う
。このサイクルを繰り返すことによって原流体の懸濁物
質濃度も上昇せずに高い透過流束を維持することが可能
となる。図４は均一な構造を持つ不織布と精密濾過膜と
の複合濾過膜の断面を示している。 図５は繊維太さ
の違う２種類の不織布を精密濾過膜に重ねた本発明の複
合濾過膜の断面構造を示している。本発明の複合膜構造
では不織布等の内部と濾過膜内部で懸濁物質が分散した
状態で阻止されるため、著しく大きな濾過抵抗とはなら
ず結果として高い濾過量が得られる。Next, a dead-end filtration system using the composite filtration membrane of the present invention will be explained based on the drawings. Figure 1 shows the state of suspended matter that accumulates on the filtration membrane when performing conventional dead-end filtration.The amount of suspended matter that accumulates increases over time, and the permeation flux eventually reaches zero. approach.
Figure 2 shows the state of suspended solids deposited on the filtration membrane when cross-flow filtration is performed.At the beginning of filtration, the suspended solids gradually increase, but the suspended solids accumulate due to the shear force of the raw fluid. The amount of substance takes a constant value, and the permeation flux eventually approaches a constant value. FIG. 3 shows the flow of the dead-end filtration method of the present invention. After filtration is performed for a certain period of time, sterilized water is passed from the permeate side to the raw fluid side and discharged together with the suspended solids desorbed from the filtration membrane. Thereafter, the sterilized water remaining in the filtration system is discharged using gas, and filtration is performed again. By repeating this cycle, it becomes possible to maintain a high permeation flux without increasing the concentration of suspended solids in the raw fluid. FIG. 4 shows a cross section of a composite filtration membrane of a nonwoven fabric with a uniform structure and a microfiltration membrane. FIG. 5 shows the cross-sectional structure of a composite filtration membrane of the present invention in which two types of nonwoven fabrics with different fiber thicknesses are stacked on a precision filtration membrane. In the composite membrane structure of the present invention, suspended substances are blocked in a dispersed state inside the nonwoven fabric and the inside of the filtration membrane, so that a significantly high filtration resistance is not caused, resulting in a high filtration rate.
【００１１】[0011]
【実施例】以下に具体例をあげて本発明をさらに詳しく
説明するが、発明の主旨を越えない限り本発明は実施例
に限定されるものではない。
実施例１
市販のバイスビール（乾燥濃度約０．３ｍｇ／ｍｌの酵
母、オリを含有する）を懸濁液として用いて、本発明の
逆洗を周期的に行うデッドエンド型濾過を行った。異方
性膜はポリスルホン（アモコ社製 Ｐ３５００）１５
部、ポリビニルピロリドン１５部、水３部を、Ｎ−メチ
ルピロリドン７０部に溶解した製膜原液を、繊維太さ約
４μｍ、空隙率７０％、厚み１００μｍのポリプロピレ
ン製の不織布に液膜厚さ１８０μｍでキャスティングコ
ーターを通して流延し、その液膜表面に２５℃相対湿度
４５％に調節した空気を２ｍ／ｓｅｃで５秒間当て、そ
の後直ちに水を満たした凝固液槽へ浸漬して作成した。
得られた濾過膜は平均孔径１．５μｍの内部緻密層を持
つ異方性の精密濾過膜であり、不織布と接する側の平均
孔径が５μｍとなった。得られた複合濾過膜の不織布側
にさらに繊維太さ４μｍ、空隙率７０％、厚み１００μ
ｍのポリプロピレン製の不織布を重ねた場合と繊維太さ
１０μｍ、空隙率７０％、厚み１００μｍのポリプロピ
レン製の不織布を重ねた場合の２つの複合膜について不
織布側を原液側として周期的逆洗を行う濾過を行った。
使用した濾過器は有効膜面積１００ｃｍ２ で、実験条
件は圧力差０．５×１０５ Ｐａ、液温度２℃であり、
濾過時間６０秒、逆洗流束５×１０−３ｍ３ ／ｍ２
／ｓｅｃ、逆洗時間４秒で行い逆洗液には滅菌水を用い
た。図６に本発明の複合膜を用いた場合と不織布を使用
せずに上記方法で作成した異方性膜を孔径の大きい方を
原液側にした場合と孔径の小さい側を原液側にした場合
の、総濾過量の経時変化を示した。 本発明の複合膜
を用いた逆洗を周期的に行うデッドエンド型濾過では高
い濾過量を示した。[Examples] The present invention will be explained in more detail with reference to specific examples below, but the present invention is not limited to the examples unless it goes beyond the gist of the invention. Example 1 Dead-end filtration in which backwashing of the present invention is performed periodically was carried out using commercially available Vice beer (containing yeast and sludge with a dry concentration of about 0.3 mg/ml) as a suspension. The anisotropic membrane is polysulfone (P3500 manufactured by Amoco)15
A membrane-forming stock solution prepared by dissolving 15 parts of polyvinylpyrrolidone, 3 parts of water in 70 parts of N-methylpyrrolidone was applied to a polypropylene nonwoven fabric with a fiber thickness of approximately 4 μm, a porosity of 70%, and a thickness of 100 μm, to a liquid film thickness of 180 μm. The film was cast through a casting coater, air adjusted to 25° C. and 45% relative humidity was applied to the surface of the liquid film at 2 m/sec for 5 seconds, and then immediately immersed in a coagulation bath filled with water. The obtained filtration membrane was an anisotropic precision filtration membrane having an internal dense layer with an average pore diameter of 1.5 μm, and the average pore diameter on the side in contact with the nonwoven fabric was 5 μm. Further, on the nonwoven fabric side of the obtained composite filtration membrane, fibers with a thickness of 4 μm, a porosity of 70%, and a thickness of 100 μm were added.
Periodic backwashing is performed on two composite membranes: one layered with polypropylene nonwoven fabrics of 100 μm in fiber thickness, 70% porosity, and 100 μm thick, with the nonwoven fabric side as the undiluted solution side. Filtered. The filter used had an effective membrane area of 100 cm2, and the experimental conditions were a pressure difference of 0.5 x 105 Pa and a liquid temperature of 2°C.
Filtration time 60 seconds, backwash flux 5 x 10-3 m3/m2
/sec, backwashing time was 4 seconds, and sterilized water was used as the backwashing liquid. Figure 6 shows a case where the composite membrane of the present invention is used, a case where the anisotropic membrane prepared by the above method without using a nonwoven fabric is made with the larger pore size on the undiluted solution side, and a case where the smaller pore size side is used as the undiluted solution side. The graph shows the change in total filtration amount over time. Dead-end filtration using the composite membrane of the present invention with periodic backwashing showed a high filtration rate.
【００１２】実施例２
実施例１の懸濁液を濾過原液として用い、実施例１の方
法で不織布に緻密層平均孔径１．５μｍの異方性の精密
濾過膜を形成させた複合濾過膜に表１で示す構成で不織
布を積層し、不織布側を原液側にして逆洗を周期的に行
うデッドエンド型濾過を行った。用いた不織布はいづれ
も空隙率約７０％、厚み５０μｍのポリプロピレン製で
ある。使用した濾過器は有効膜面積１００ｃｍ２ で、
実験条件は圧力差０．５×１０５ Ｐａ、液温度２℃で
あり、濾過時間６０秒、逆洗流束５×１０−３ｍ３ ／
ｍ２ ／ｓｅｃ、逆洗時間４秒で行い逆洗液には滅菌水
を用いた。図７に各複合濾過膜を不織布側を原液側とし
て用いた場合の総濾過量の経時変化を示した。この結果
、不織布繊維の太さが原液側に向かって段階的に太くな
る多層構造の不織布を用いる方が高い濾過量が得られた
。Example 2 Using the suspension of Example 1 as a filtration stock solution, an anisotropic microfiltration membrane with a dense layer average pore diameter of 1.5 μm was formed on a nonwoven fabric using the method of Example 1. Nonwoven fabrics were laminated in the configuration shown in Table 1, and dead-end filtration was performed in which backwashing was performed periodically with the nonwoven fabric side facing the stock solution side. The nonwoven fabrics used were all made of polypropylene with a porosity of about 70% and a thickness of 50 μm. The filter used had an effective membrane area of 100 cm2.
The experimental conditions were a pressure difference of 0.5 x 105 Pa, a liquid temperature of 2°C, a filtration time of 60 seconds, and a backwash flux of 5 x 10-3 m3/
m2/sec, backwashing time was 4 seconds, and sterilized water was used as the backwashing liquid. FIG. 7 shows the change over time in the total filtration amount when each composite filtration membrane was used with the nonwoven fabric side serving as the stock solution side. As a result, a higher filtration rate was obtained by using a nonwoven fabric with a multilayer structure in which the thickness of the nonwoven fabric fibers gradually became thicker toward the stock solution side.
【００１３】[0013]
【表１】[Table 1]
【００１４】[0014]
【発明の効果】本発明によれば、複合膜を用いた逆洗を
周期的に行うデッドエンド型濾過方式において高い膜透
過流束が得られ、それによって種々の懸濁物質を含有す
る液体から各懸濁成分の分離、回収、精製、濃縮などが
きわめて効率的しかも経済的に行われる。そしてさらに
プロセスの連続化及び装置の小型化が可能であり、膜の
選択性を利用して目的物のみを連続的に選択的に分離す
ることができ、酵母や菌体などのバイオリアクターへの
応用ができ、従来技術に比べて運転管理が容易であるな
ど諸々の効果が奏せられる。Effects of the Invention According to the present invention, a high membrane permeation flux can be obtained in a dead-end filtration system in which backwashing is performed periodically using a composite membrane. Separation, recovery, purification, concentration, etc. of each suspended component are performed extremely efficiently and economically. Furthermore, it is possible to make the process continuous and downsize the equipment, and by utilizing the selectivity of the membrane, it is possible to continuously and selectively separate only the target substance, and it is possible to separate only the target substance continuously and selectively, and it is possible to use the membrane to selectively separate only the target substance. It can be applied and has various effects such as easier operation management than conventional technology.
【図１】従来のデッドエンド型濾過における懸濁物質の
堆積状態を示している。FIG. 1 shows the state of accumulation of suspended solids in conventional dead-end filtration.
【図２】従来のクロスフロー濾過における懸濁物質の堆
積状態を示している。FIG. 2 shows the state of accumulation of suspended solids in conventional cross-flow filtration.
【図３】本発明の逆洗を周期的に行うデッドエンド型濾
過方式のフローを示している。FIG. 3 shows a flowchart of a dead-end filtration system in which backwashing is performed periodically according to the present invention.
【図４】均一な構造を持つ不織布と精密濾過膜との複合
膜の断面を示している。FIG. 4 shows a cross section of a composite membrane of a nonwoven fabric and a microfiltration membrane with a uniform structure.
【図５】本発明の複合濾過膜の断面を示している。FIG. 5 shows a cross section of a composite filtration membrane of the present invention.
【図６】バイスビールを用いて本発明の複合膜および従
来の精密濾過膜で逆洗を周期的に行うデッドエンド型濾
過を行った際の総濾過量を示している。FIG. 6 shows the total filtration amount when dead-end filtration with periodic backwashing is performed using the composite membrane of the present invention and a conventional microfiltration membrane using Vice beer.
【図７】バイスビールを用いて本発明の不織布繊維を多
層構造にした複合膜を用いて逆洗を周期的に行うデッド
エンド型濾過を行った際の総濾過量を示している。FIG. 7 shows the total filtration amount when dead-end filtration in which backwashing is performed periodically using a composite membrane of the present invention having a multilayer structure of nonwoven fibers is performed using Vice beer.
１ デッドエンド濾過の原流体の流れ２ デッドエ
ンド濾過の透過液の流れ３ デッドエンド濾過の懸濁
物質の移動方向４ 濾過膜上に堆積している懸濁物質
５ 濾過膜
６ クロスフロー濾過の原流体の流れ７ クロスフ
ロー濾過の透過液の流れ８ クロスフロー濾過の懸濁
物質の移動方向９ 濾過膜上に堆積している懸濁物質
１０ 濾過膜
１１ 原流体入口
１２ 透過液出口
１３ 逆洗液入口
１４ 排液出口
１５ 濾過器
１６ 濾過膜
１７ ガス入口
１８ 圧力計
１９ ポンプ
２０ 滅菌フィルター
２１ 電磁弁
２２ 濾過膜断面
２３ 懸濁物質
２４ 濾過膜断面
２５ 懸濁物質
２６ 濾過膜断面
２７ 不織布断面
２８ 懸濁物質
２９ 本発明の複合濾過膜（１０μｍ 繊維不織布を
重ねた場合）
３０ 本発明の複合濾過膜（４μｍ 繊維不織布を重
ねた場合）
３１ 孔径の大きい方を原液側とした異方性膜３２
孔径の小さい方を原液側とした異方性膜３３ 複合
膜１
３４ 複合膜２
３５ 複合膜３1 Flow of raw fluid in dead-end filtration 2 Flow of permeate in dead-end filtration 3 Movement direction of suspended solids in dead-end filtration 4 Suspended solids deposited on the filtration membrane 5 Filter membrane 6 Raw material in cross-flow filtration Fluid flow 7 Flow of permeate in cross-flow filtration 8 Movement direction of suspended solids in cross-flow filtration 9 Suspended solids deposited on the filtration membrane 10 Filtration membrane 11 Raw fluid inlet 12 Permeate outlet 13 Backwash liquid Inlet 14 Drainage outlet 15 Filter 16 Filtration membrane 17 Gas inlet 18 Pressure gauge 19 Pump 20 Sterilization filter 21 Solenoid valve 22 Filtration membrane cross section 23 Suspended solids 24 Filtration membrane cross section 25 Suspended solids 26 Filtration membrane cross section 27 Nonwoven fabric cross section 28 Suspension Turbid substance 29 Composite filtration membrane of the present invention (when 10 μm fibrous nonwoven fabrics are stacked) 30 Composite filtration membrane of the present invention (when 4 μm fibrous nonwoven fabrics are stacked) 31 Anisotropic membrane 32 with the larger pore size on the stock solution side
Anisotropic membrane 33 with the smaller pore size facing the stock solution side Composite membrane 1 34 Composite membrane 2 35 Composite membrane 3
Claims (5)
流体からなる原液を供給し濾過することにより流体と懸
濁物質とを分離する濾過方式において、濾過膜が精密濾
過膜と不織布、織布またはガラス繊維との積層複合膜で
あり、不織布、織布またはガラス繊維が厚さ方向に多層
構造をもつことを特徴とする複合濾過膜。Claim 1. A filtration method that uses a microfiltration membrane to separate a fluid and suspended substances by supplying and filtering a stock solution consisting of a fluid containing suspended substances, the filtration membrane comprising a microfiltration membrane, a nonwoven fabric, A composite filtration membrane that is a laminated composite membrane with woven fabric or glass fiber, and characterized in that the nonwoven fabric, woven fabric, or glass fiber has a multilayer structure in the thickness direction.
ラス繊維の側を原液側に向けて用い、不織布、織布、ガ
ラス繊維の濾過膜側の繊維太さが、接する面の濾過膜表
面孔径の０．５倍以上５倍以下の太さであり、原液側に
向かって繊維太さが太くなる多層構造を有することを特
徴とする請求項１項に記載の複合濾過膜。2. The composite filtration membrane is used with the nonwoven fabric, woven fabric, or glass fiber side facing the stock solution side, and the fiber thickness of the nonwoven fabric, woven fabric, or glass fiber on the filtration membrane side is the same as the filtration membrane surface of the contacting surface. The composite filtration membrane according to claim 1, characterized in that it has a multilayer structure with a thickness of 0.5 times or more and 5 times or less of the pore diameter, and the fiber thickness becomes thicker toward the undiluted solution side.
力を原液側の圧力より大きくして周期的に逆洗を行い、
逆洗液と共に濾過膜から脱着した懸濁物質を濾過系外へ
排出するデッドエンド型濾過方式に使用することを特徴
とする請求項１項記載の複合濾過膜。3. Periodically backwashing the composite filtration membrane by making the pressure on the permeate side of the filtration membrane higher than the pressure on the stock solution side,
2. The composite filtration membrane according to claim 1, wherein the composite filtration membrane is used in a dead-end filtration system in which suspended solids desorbed from the filtration membrane are discharged from the filtration system together with the backwash liquid.
たはガラス繊維に含浸していることを特徴とする請求項
１項記載の複合濾過膜。4. The composite filtration membrane according to claim 1, wherein a part of the microfiltration membrane is impregnated with nonwoven fabric, woven fabric, or glass fiber.
的または不連続的に変化し、精密濾過膜の一方の表面孔
径と他方の表面孔径とが異なる異方性構造を有し、表面
孔径の大きい側に不織布、織布またはガラス繊維が存在
することを特徴とする請求項１項記載の複合濾過膜。5. The microfiltration membrane has an anisotropic structure in which the pore diameter changes continuously or discontinuously in the membrane thickness direction, and the pore diameter on one surface of the microfiltration membrane is different from the pore diameter on the other surface, 2. The composite filtration membrane according to claim 1, wherein a nonwoven fabric, woven fabric, or glass fiber is present on the side with larger surface pores.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8693591A JPH04317729A (en) | 1991-04-18 | 1991-04-18 | Composite filtration membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8693591A JPH04317729A (en) | 1991-04-18 | 1991-04-18 | Composite filtration membrane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04317729A true JPH04317729A (en) | 1992-11-09 |
Family
ID=13900727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8693591A Pending JPH04317729A (en) | 1991-04-18 | 1991-04-18 | Composite filtration membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04317729A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006150323A (en) * | 2004-11-01 | 2006-06-15 | Japan Gore Tex Inc | Diaphragm and production method of the same and heat exchanger equipped with the same |
| KR101294827B1 (en) * | 2011-11-14 | 2013-08-09 | 엘지전자 주식회사 | Automatically Filter-Washable Water Purifier |
| WO2022181195A1 (en) * | 2021-02-24 | 2022-09-01 | 国立研究開発法人物質・材料研究機構 | Separation-membrane nonwoven fabric and manufacturing method therefor |
-
1991
- 1991-04-18 JP JP8693591A patent/JPH04317729A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006150323A (en) * | 2004-11-01 | 2006-06-15 | Japan Gore Tex Inc | Diaphragm and production method of the same and heat exchanger equipped with the same |
| KR101294827B1 (en) * | 2011-11-14 | 2013-08-09 | 엘지전자 주식회사 | Automatically Filter-Washable Water Purifier |
| WO2022181195A1 (en) * | 2021-02-24 | 2022-09-01 | 国立研究開発法人物質・材料研究機構 | Separation-membrane nonwoven fabric and manufacturing method therefor |
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