JPH11197459A - Membrane filter apparatus - Google Patents
Membrane filter apparatusInfo
- Publication number
- JPH11197459A JPH11197459A JP853998A JP853998A JPH11197459A JP H11197459 A JPH11197459 A JP H11197459A JP 853998 A JP853998 A JP 853998A JP 853998 A JP853998 A JP 853998A JP H11197459 A JPH11197459 A JP H11197459A
- Authority
- JP
- Japan
- Prior art keywords
- water
- membrane
- backwashing
- backwash
- membrane module
- 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.)
- Granted
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- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は膜濾過装置に係り、
特に、原水の通水を継続しながら、透過水側から逆洗水
を圧入して逆洗を行う膜濾過装置において、膜の損傷の
原因となる逆洗時の原水の脈動流の発生を防止して長期
連続運転を可能とした膜濾過装置に関する。TECHNICAL FIELD The present invention relates to a membrane filtration device,
In particular, in a membrane filtration device that performs backwashing by injecting backwashing water from the permeated water side while continuing the flow of raw water, it prevents the generation of pulsating flow of raw water during backwashing that causes damage to the membrane. The present invention relates to a membrane filtration device capable of long-term continuous operation.
【0002】[0002]
【従来の技術】原水の濁質除去を目的とする限外濾過
(UF)又は精密濾過(MF)等の膜濾過装置では、膜
モジュールに供給された原水中の固形分は膜によって分
離され、膜を透過した透過水と固形分濃度が高くなった
濃縮水とに分けられる。この濃縮水は排出されるか、循
環槽に返送され再度膜モジュールに供給される。このよ
うな膜濾過を継続すると、膜の目詰りによりフラックス
(透過水量)が低下してくるため、定期的(間欠的)
に、例えば数分〜数百分の原水の通水に対して数秒〜数
分の頻度で、原水の通水を継続したまま、膜の透過水側
から逆洗水を逆流させて膜面に付着した濁質ケーキを剥
離、除去する逆洗を行って、フラックスを回復させるこ
とがある。通常、この逆洗水としては、透過水の一部を
逆洗タンクに貯留しておいたものが用いられるが、別の
洗浄用水を用いる場合もある。2. Description of the Related Art In a membrane filtration device such as ultrafiltration (UF) or microfiltration (MF) for removing turbidity of raw water, solids in raw water supplied to a membrane module are separated by a membrane. It is divided into permeated water that has passed through the membrane and concentrated water having a high solid content concentration. This concentrated water is discharged or returned to the circulation tank and supplied to the membrane module again. If such membrane filtration is continued, the flux (permeated water amount) decreases due to clogging of the membrane.
Then, for example, at a frequency of several seconds to several minutes with respect to the flow of the raw water for several minutes to several hundred minutes, the backwash water is caused to flow backward from the permeated water side of the membrane while the flow of the raw water is continued, and the flow is returned to the membrane surface. The flux may be recovered by performing backwashing to remove and remove the adhered turbid cake. Usually, a part of the permeated water stored in the backwash tank is used as the backwash water, but another wash water may be used.
【0003】このように、原水の通水を継続しながら逆
洗水を供給する逆洗方法では、通常、逆洗の間、透過水
の採水は行わず、膜モジュールに流入した原水は濃縮水
取出管から系外へ排出されるか、原水側へ返送される。[0003] As described above, in the backwashing method in which backwash water is supplied while continuing the flow of raw water, normally, permeate water is not collected during backwash, and the raw water flowing into the membrane module is concentrated. It is discharged out of the system from the water discharge pipe or returned to the raw water side.
【0004】ところで、クロスフロー濾過方式でしかも
上記の如く定期的に逆洗を行う従来の膜濾過装置では、
多くの場合、複数の膜モジュールを直列に接続すること
なく、すべて並列に接続した装置構成とされていたが、
この場合、原水流量と透過水流量との比は一般に1:
0.06〜0.15程度で採水効率が小さいという欠点
があった。[0004] By the way, in a conventional membrane filtration apparatus which performs a cross-wash filtration method and also performs a regular backwash as described above,
In many cases, instead of connecting a plurality of membrane modules in series, it was configured as an apparatus in which all were connected in parallel.
In this case, the ratio between the raw water flow rate and the permeate flow rate is generally 1:
There was a disadvantage that the water sampling efficiency was low at about 0.06 to 0.15.
【0005】これに対して、複数の膜モジュールを直列
に接続したもの、例えば、2本の膜モジュールを直列に
接続したものでは、原水流量と透過水流量の比は1:
0.15〜0.30或いはそれ以上となり、採水効率が
高いことから、近年、直列型の膜濾過装置の開発が進め
られている。On the other hand, in the case where a plurality of membrane modules are connected in series, for example, in the case where two membrane modules are connected in series, the ratio of the raw water flow rate to the permeate flow rate is 1:
Since the water sampling efficiency is 0.15 to 0.30 or more and the water sampling efficiency is high, development of a series type membrane filtration device has recently been advanced.
【0006】[0006]
【発明が解決しようとする課題】前述の如く、原水の通
水を継続しながら、逆洗水を逆流させる逆洗を行った場
合、逆洗時に膜モジュールに流入する原水圧力が通水濾
過時(逆洗を行っていない透過水採水時)に比べて高く
なり、また、膜モジュールへの原水流入量は通水濾過時
に比べて減少する。As described above, when backwashing is performed in which backwash water flows backward while continuing the flow of raw water, the pressure of the raw water flowing into the membrane module at the time of backwashing is increased when the water is filtered. (At the time of permeated water sampling without backwashing), and the amount of raw water flowing into the membrane module is smaller than at the time of passing water filtration.
【0007】この現象は、逆洗時に逆洗水が膜を透過し
て濃縮水側に移行してくるため、この濃縮水側への移行
水が、原水が通過する濃縮水側流路を一部遮断すること
によるものと考えられる。[0007] This phenomenon occurs because the backwash water permeates the membrane during the backwash and moves to the concentrated water side, and the water transferred to the concentrated water side passes through the concentrated water side passage through which the raw water passes. This is probably due to the interruption of the part.
【0008】そして、このような原水の圧力と流入量が
変動するところから、逆洗の都度、膜モジュールへの流
入原水に脈動流が発生するようになる。そして、このよ
うな脈動が繰り返し膜に負荷されることにより膜が損傷
し易いものとなる。[0008] When the pressure and inflow amount of the raw water fluctuate, a pulsating flow is generated in the raw water flowing into the membrane module every time the backwashing is performed. When such pulsation is repeatedly applied to the membrane, the membrane is easily damaged.
【0009】この脈動流は、複数の膜モジュールを並列
に接続した膜濾過装置でも生じるが、特に、複数の膜モ
ジュールを直列に接続した膜濾過装置において、直列に
接続した膜モジュール数が多い程大きく、とりわけ、こ
のような直列型の膜濾過装置で各膜モジュールを同時逆
洗した場合には、著しく大きな脈動流が発生することか
ら、膜は早期に損傷するようになる。This pulsating flow also occurs in a membrane filtration device in which a plurality of membrane modules are connected in parallel. In particular, in a membrane filtration device in which a plurality of membrane modules are connected in series, the larger the number of membrane modules connected in series, the greater the number of membrane modules connected in series. If the membrane modules are large and, in particular, simultaneously backwash each membrane module in such a series membrane filtration device, the membrane will be damaged prematurely due to the generation of a significantly large pulsating flow.
【0010】上記逆洗時の脈動流による影響はまた、例
えば、石膏粒子を含有する石炭焚きの火力発電所の排煙
脱硫排水の中和・凝集処理水を膜濾過する場合や、原水
に50μm以上の粒径の粉末活性炭を添加した後膜濾過
する場合のように、高硬度ないし大粒径の粒子を含む原
水が流入する場合に大きく、膜は早期に損傷するように
なる。[0010] The influence of the pulsating flow at the time of the backwashing may also be caused, for example, by membrane filtration of flue gas desulfurization wastewater from coal-fired thermal power plants containing gypsum particles, or by 50 μm in raw water. When raw water containing particles having a high hardness or a large particle size flows in, for example, when membrane filtration is performed after adding powdered activated carbon having the above particle size, the membrane is damaged at an early stage.
【0011】本発明は上記従来の問題点を解決し、膜の
損傷の原因となる逆洗時の原水の脈動流を低減し、長期
連続運転が可能な膜濾過装置を提供することを目的とす
る。SUMMARY OF THE INVENTION It is an object of the present invention to provide a membrane filtration apparatus which solves the above-mentioned conventional problems, reduces the pulsating flow of raw water at the time of backwashing which causes damage to the membrane, and enables long-term continuous operation. I do.
【0012】[0012]
【課題を解決するための手段】本発明の膜濾過装置は、
内部を濃縮水側と透過水側とに区画する濾過膜を具備す
る膜モジュールと、該膜モジュールの濃縮水側に原水を
供給する原水供給管と、該濾過膜を透過した透過水を該
膜モジュールから取り出す透過水取出管と、濃縮水を該
膜モジュールから取り出す濃縮水取出管と、逆洗水を膜
モジュールの透過水側に圧入する逆洗水供給手段とを有
し、原水を供給しつつ間欠的に逆洗水を膜モジュールに
圧入して該濾過膜を逆洗するようにした膜濾過装置にお
いて、濃縮水の一部を排出する排出管が、前記濃縮水取
出管から分岐して、或いは、濃縮水取出管とは別に膜モ
ジュールの濃縮水側に接続して設けられ、逆洗水が膜モ
ジュールに圧入されている間、開状態に制御される弁が
該排出管に設けられていることを特徴とする。The membrane filtration device of the present invention comprises:
A membrane module having a filtration membrane that partitions the interior into a concentrated water side and a permeated water side; a raw water supply pipe for supplying raw water to the concentrated water side of the membrane module; A permeate discharge pipe for removing raw water from a module, a concentrated water discharge pipe for extracting concentrated water from the membrane module, and a backwash water supply means for injecting backwash water into the permeate side of the membrane module; In a membrane filtration device in which backwash water is intermittently pressed into a membrane module to backwash the filtration membrane, a discharge pipe for discharging a part of the concentrated water branches off from the concentrated water discharge pipe. Alternatively, a valve is connected to the concentrated water side of the membrane module separately from the concentrated water discharge pipe, and a valve that is controlled to be open while the backwash water is being pressed into the membrane module is provided in the discharge pipe. It is characterized by having.
【0013】かかる本発明の膜濾過装置では、逆洗時に
排出管の弁を開として濃縮水の一部を排出することによ
り、逆洗時の原水の圧力増加及び流入量減少の程度を低
減することができる。このように逆洗時の原水圧力及び
流入量の変動を小さくすることにより、脈動流の発生を
防止し、脈動流による膜の損傷を防止することができ
る。In the membrane filtration apparatus of the present invention, the degree of the increase in the pressure of the raw water and the decrease in the amount of inflow during the backwash are reduced by opening the valve of the discharge pipe and discharging a part of the concentrated water during the backwash. be able to. By reducing the fluctuations of the raw water pressure and the inflow amount at the time of backwashing, generation of a pulsating flow can be prevented, and damage to the membrane due to the pulsating flow can be prevented.
【0014】[0014]
【発明の実施の形態】以下、図面を参照して本発明の実
施の形態を説明する。Embodiments of the present invention will be described below with reference to the drawings.
【0015】図1は本発明の膜濾過装置の実施の形態を
示す系統図である。図中、M11,M12,M13,M21,M
22,M23,M31,M32,M33は膜モジュール、H1 ,H
2 ,H3 ,H4 はマニホルド、V10,V20,V30は逆洗
弁(自動弁)、V11,V21,V31は透過水出口弁(自動
弁)、V12,V22,V32は濃縮水排出弁(自動弁)、V
13,V23,V33は定流量弁、V14,V24,V34は流量調
節弁、Wは逆洗タンク、Lは水位計、V40はエア抜き
弁、V41は水位計Lに連動する逆洗水水張り弁、VA1,
VA2,VA3は遮断弁、VB1,VB2,VB3は調圧弁(圧力
調整弁)である。M1 ,M2 ,M3 は3本の膜モジュー
ルが並列された膜モジュール群を示す。FIG. 1 is a system diagram showing an embodiment of a membrane filtration device according to the present invention. In the figure, M 11, M 12, M 13, M 21, M
22 , M 23 , M 31 , M 32 , M 33 are membrane modules, H 1 , H
2, H 3, H 4 manifolds, V 10, V 20, V 30 is the backwash valve (automatic valve), V 11, V 21, V 31 is the permeate outlet valve (automatic valve), V 12, V 22 , V 32 are concentrated water discharge valve (automatic valve), V
13, V 23, V 33 is constant flow valve, V 14, V 24, V 34 are flow control valve, W is backwash tank, L is water gauges, V 40 is an air vent valve, V 41 the level gauge L Interlocking backwash water filling valve, V A1 ,
VA2 and VA3 are shut-off valves, and VB1 , VB2 and VB3 are pressure regulating valves (pressure regulating valves). M 1 , M 2 , and M 3 indicate a membrane module group in which three membrane modules are arranged in parallel.
【0016】この膜濾過装置は、3本の膜モジュールが
並列に配置された膜モジュール群M1 ,M2 ,M3 が、
3段に直列に配置されたものであり、上流側の膜モジュ
ール群の濃縮水が順次下流側の膜モジュール群に流入
し、透過水は各段毎に集水され、各々透過水出口弁
V11,V21,V31及び定流量弁V13,V23,V33を経て
抜き出され、更に集水されて系外へ排出される。なお、
この透過水の一部は必要に応じて逆洗水水張り弁V41よ
り逆洗タンクWに流入する。この逆洗タンクWには水位
計Lが設けられており、設定した水位まで透過水が流入
すると水張り弁V41を閉として透過水の導入を停止す
る。In this membrane filtration device, a membrane module group M 1 , M 2 , M 3 in which three membrane modules are arranged in parallel,
The concentrated water of the upstream membrane module group sequentially flows into the downstream membrane module group, and the permeated water is collected at each stage, and each of the permeated water outlet valves V 11, through the V 21, V 31 and constant flow valve V 13, V 23, V 33 is withdrawn, and is discharged further water collecting in the outside of the system. In addition,
Some of the permeate flows from the backwash water the water filling valve V 41 to backwash tank W as needed. This is the backwash tank W is water gauge L are provided, permeate up to the water level set to stop the introduction of the permeated water to the water filling valve V 41 when entering as closed.
【0017】各膜モジュール群M1 ,M2 ,M3 には各
々の膜モジュールの透過水側に逆洗タンクWの逆洗水を
圧入する逆洗弁V10,V20,V30が設けられており、逆
洗時には、逆洗タンクWの空気貯め部に連結したコンプ
レッサ(図示せず)により、調圧弁VB1,VB2,VB3及
び遮断弁VA1,VA2,VA3を介して加圧空気が供給さ
れ、この加圧力で逆洗水が各膜モジュールに供給され
る。Each membrane module group M 1 , M 2 , M 3 is provided with a backwash valve V 10 , V 20 , V 30 for pressurizing backwash water in the backwash tank W on the permeate side of each membrane module. At the time of backwashing, a compressor (not shown) connected to the air reservoir of the backwashing tank W allows the air to flow through the pressure regulating valves VB1 , VB2 , VB3 and the shutoff valves VA1 , VA2 , VA3 . And pressurized air is supplied to the membrane module.
【0018】また、各膜モジュール群M1 ,M2 ,M3
の出口側のマニホルドH2 ,H3 ,H4 には、各々濃縮
水排出弁V12,V22,V32及び流量調節弁V14,V24,
V34を有する濃縮水排出ラインが設けられている。Further, each of the membrane module groups M 1 , M 2 , M 3
The outlets of the manifolds H 2 , H 3 , H 4 are respectively provided with concentrated water discharge valves V 12 , V 22 , V 32 and flow control valves V 14 , V 24 ,
Concentrated water discharge line is provided with a V 34.
【0019】各膜モジュール群M1 ,M2 ,M3 の透過
水出口弁V11,V21,V31とこの濃縮水排出弁V12,V
22,V32は、各々、逆洗弁V10,V20,V30の開閉に対
応して次のように開閉する。The permeated water outlet valves V 11 , V 21 , V 31 of each of the membrane module groups M 1 , M 2 , M 3 and the concentrated water discharge valves V 12 , V 3
22, V 32 are each, in response to opening and closing of the backwash valve V 10, V 20, V 30 to open and close as follows.
【0020】[0020]
【表1】 [Table 1]
【0021】このように逆洗時に弁の開閉を制御するこ
とにより、膜モジュールの透過水側から濃縮水側へ逆洗
水が圧入される際の脈動流の発生を大幅に低減すること
ができる。即ち、従来においては、原水の通水を継続し
ながら逆洗を行う場合、逆洗時に透過水側から濃縮水側
へ逆流することによって増加した水が、原水(濃縮水)
側の圧力を高め、また、原水流入量を低減させ、これが
脈動流の原因となっていたが、図示の如く、濃縮水排出
弁V12,V22,V32を設け、逆洗時に、この濃縮水排出
弁V12,V22,V32を開として、逆洗水の流入で濃縮水
側で増加した水量に見合う量の水を排出することによ
り、上記圧力増加、流入量低減を防止し、逆洗時の圧力
及び流入量を通水濾過時と同等に平準化させることがで
きる。そして、これにより脈動流の発生を防止すること
ができる。By controlling the opening and closing of the valve at the time of backwashing as described above, the generation of pulsating flow when backwashing water is injected into the concentrated water side from the permeated water side of the membrane module can be greatly reduced. . That is, conventionally, when backwashing is performed while continuing the flow of raw water, the water increased by backflow from the permeated water side to the concentrated water side at the time of backwashing is reduced to the raw water (concentrated water).
Increasing the pressure side, also reduces the raw water inflow, but this has been a cause of pulsatile flow, as shown, provided the concentrated water discharge valve V 12, V 22, V 32 , during backwashing, the By opening the concentrated water discharge valves V 12 , V 22 , and V 32 and discharging the amount of water corresponding to the amount of water increased on the concentrated water side by the inflow of the backwash water, the above-described increase in pressure and reduction in the amount of inflow can be prevented. In addition, the pressure and the amount of inflow at the time of back washing can be equalized as at the time of water filtration. Thus, the generation of the pulsating flow can be prevented.
【0022】なお、濃縮水排出弁V12,V22,V32から
の濃縮水排出量は、その開閉の度合や口径等によって左
右され、一方で、圧力及び流入量の平準化作用で、脈動
流の発生を安定かつ確実に防止するためには、濃縮水の
排出量を適正量とする必要があることから、各濃縮水排
出弁V12,V22,V32の設置ラインには図示の如く、各
々流量調整弁V14,V24,V34を設け、その開度調整で
濃縮水の排出量を制御するのが好ましい。The amount of concentrated water discharged from the concentrated water discharge valves V 12 , V 22 , and V 32 depends on the degree of opening and closing, the diameter, and the like. On the other hand, the level of pressure and the amount of inflow cause pulsation. In order to stably and surely prevent the generation of flow, it is necessary to discharge the concentrated water at an appropriate amount. Therefore, the installation lines of the concentrated water discharge valves V 12 , V 22 , and V 32 are not shown in the drawing. as each flow regulating valve V 14, V 24, V 34 provided, it is preferable to control the emissions of concentrated water in its opening adjustment.
【0023】ところで、脈動流の防止の点からは、逆洗
時の有効逆洗圧(逆洗時の透過水(逆洗水)側圧力と原
水(濃縮水)側圧力との差)を0.02〜0.15MP
aの適正範囲に抑えることに加えて、複数の膜モジュー
ルを直列に接続した膜濾過装置においては、1基の逆洗
タンクによる逆洗では各段の膜モジュールの有効逆洗圧
を均等にすることが望ましいが、このように逆洗圧を各
段において均等にするにはそのための特別な付帯設備が
必要であった。From the viewpoint of preventing pulsating flow, the effective backwash pressure during backwashing (the difference between the pressure of the permeated water (backwash water) and the pressure of the raw water (concentrated water) during backwash) is set to 0. .02-0.15MP
In addition to keeping the a within the appropriate range, in a membrane filtration device in which a plurality of membrane modules are connected in series, the backwashing with one backwash tank equalizes the effective backwash pressure of the membrane modules in each stage. However, in order to equalize the backwash pressure in each stage, a special auxiliary equipment is required.
【0024】例えば、図示の如く、3段に直列に膜モジ
ュール群M1 〜M3 を接続したものにおいて、1基の逆
洗タンクで逆洗を行うと、最上段の膜モジュール群M1
の有効逆洗圧は0.02MPa、中段の膜モジュール群
M2 の有効逆洗圧は0.06MPa、最下段の膜モジュ
ール群M3 の有効逆洗圧は0.1MPaというように適
正範囲内に抑えられるものの、その値には大きな差が生
じる。このため、従来においては、各段の有効逆洗圧を
個別に制御しうるようにするために各段毎に逆洗タンク
を設けているが、このようにすることによりタンク数や
設置スペースが増え、運転管理の面でも作業数が多いと
いう欠点があった。For example, as shown in the figure, in the case where the membrane module groups M 1 to M 3 are connected in series in three stages, when backwashing is performed in one backwash tank, the uppermost membrane module group M 1
The effective Gyakuarai圧0.02 MPa, the effective Gyakuarai圧the middle membrane modules M 2 is 0.06 MPa, the effective Gyakuarai圧of the lowermost membrane modules M 3 are in the proper range so as 0.1MPa However, there is a large difference in the values. For this reason, in the related art, a backwash tank is provided for each stage so that the effective backwash pressure of each stage can be individually controlled, but by doing so, the number of tanks and installation space are reduced. There was a disadvantage that the number of operations was large in terms of operation management.
【0025】これに対し、本実施の形態では、3段の膜
モジュール群M1 ,M2 ,M3 に対して1基の逆洗タン
クWを設け、この逆洗タンクWに各々の膜モジュール群
M1,M2 ,M3 に対応する圧力調節手段を設けて各膜
モジュール群M1 ,M2 ,M3 の有効逆洗圧を制御でき
るように構成している。On the other hand, in this embodiment, one backwash tank W is provided for the three-stage membrane module groups M 1 , M 2 , and M 3 , and each backwash tank W is provided in the backwash tank W. Pressure adjusting means corresponding to the groups M 1 , M 2 and M 3 are provided so that the effective backwash pressure of each of the membrane module groups M 1 , M 2 and M 3 can be controlled.
【0026】即ち、図1において、遮断弁VA1と調圧弁
VB1は膜モジュール群M1 の有効逆洗圧の設定のための
ものであり、遮断弁VA2と調圧弁VB2は膜モジュール群
M2の有効逆洗圧の設定のためのものであり、遮断弁V
A3と調圧弁VB3は膜モジュール群M3 の有効逆洗圧の設
定のためのものであり、各調圧弁VB1,VB2,VB3はコ
ンプレッサからの加圧空気を各々の膜モジュール群
M1 ,M2 ,M3 の逆洗に好適な所定圧力で逆洗タンク
Wに送給するように設定され、遮断弁VA1,VA2,VA3
は各々逆洗弁V10,V20,V30に同期して開閉制御され
る。[0026] That is, in FIG. 1, the shutoff valve V A1 Doo regulating valve V B1 is for setting the effective backwashing pressure of membrane modules M 1, the membrane module shut-off valve V A2 Doo regulating valve V B2 It is for setting the effective backwashing pressure of the group M 2, shut-off valves V
A3 DOO regulating valve V B3 is for setting the effective backwashing pressure of membrane modules M 3, the pressurized air each membrane module group from the pressure regulating valve V B1, V B2, V B3 is compressor It is set so as to feed the backwash tank W at a predetermined pressure suitable for backwashing of M 1 , M 2 , M 3 , and the shutoff valves V A1 , V A2 , V A3
Controlled to open and close in synchronization with each backwash valves V 10, V 20, V 30 it is.
【0027】このように、直列に接続した膜モジュール
又は膜モジュール群毎に有効逆洗圧調節手段を設けるこ
とにより、1基の逆洗タンク及び共通の逆洗水供給配管
等により各段の有効逆洗圧を均等にして各膜モジュール
を逆洗することができる。As described above, by providing the effective backwash pressure adjusting means for each membrane module or group of membrane modules connected in series, the effective backwash pressure of each stage can be increased by one backwash tank and a common backwash water supply pipe. Each membrane module can be backwashed with equal backwash pressure.
【0028】なお、逆洗時にはエア抜き弁V40は閉とさ
れる。逆洗終了後に該エア抜き弁V40を開として、水位
計Lに連動する逆洗水水張り弁V41より透過水を所定水
位まで逆洗タンクW内に貯める。[0028] In addition, the air vent valve V 40 at the time of backwash is closed. The air vent valve V 40 after completion of backwashing is opened, store permeate from the backwash water the water filling valve V 41 interlocked with the water gauge L backwash tank W up to a predetermined water level.
【0029】図示の膜濾過装置は、3本の膜モジュール
を並列配置した膜モジュール群を3段に直列に接続した
ものであるが、本発明において、膜モジュールの接続数
や接続形態に特に制限はなく、1本の膜モジュールのみ
を設置した膜濾過装置であっても良い。In the illustrated membrane filtration apparatus, a membrane module group in which three membrane modules are arranged in parallel is connected in series in three stages. In the present invention, the number of connected membrane modules and the form of connection are particularly limited. Instead, a membrane filtration device provided with only one membrane module may be used.
【0030】ただし、前述の如く、脈動流及びそれによ
る膜の損傷は膜モジュールの直列に接続する数が多いほ
ど起こり易いことから、本発明は、特に、膜モジュール
を直列に多段に接続した膜濾過装置に適用することによ
り、顕著な効果を得ることができる。However, as described above, the pulsating flow and the damage to the membrane due to the pulsating flow are more likely to occur as the number of membrane modules connected in series increases. Therefore, the present invention is particularly applicable to a membrane in which membrane modules are connected in multiple stages in series. A remarkable effect can be obtained by applying to a filtration device.
【0031】このように膜モジュールが直列に多段に接
続されている膜濾過装置において、各段の膜モジュール
の逆洗は同時に行っても、順次行っても良い。In such a membrane filtration device in which the membrane modules are connected in multiple stages in series, backwashing of the membrane modules in each stage may be performed simultaneously or sequentially.
【0032】なお、各段の膜モジュールの逆洗を順次行
うようにした場合であれば、一つの段の膜モジュールが
逆洗されているときでも他の段の膜モジュールでは透過
水採水運転が行われるので、常時透過水を得ることがで
きるという利点がある。また、図示の如く、各段の膜モ
ジュール毎に有効逆洗圧調節のための調圧弁及び遮断弁
を設け、各段の膜モジュール毎に有効逆洗圧の調節を行
う点からも、順次逆洗を行うようにするのが好ましい。
この場合、逆洗の周期が重なるようであれば、どの段の
膜モジュールの逆洗を優先させるかを予め設定してお
き、タイマーにより、各段の膜モジュールの逆洗操作を
順次実行させるのが好ましい。In the case where the backwashing of the membrane modules of each stage is performed sequentially, even if the backwashing of the membrane module of one stage is performed, the permeated water sampling operation is performed in the other stage of the membrane module. Therefore, there is an advantage that permeated water can be always obtained. Further, as shown in the drawing, a pressure regulating valve and a shutoff valve for adjusting the effective backwash pressure are provided for each membrane module in each stage, and the reverse backwash pressure is adjusted for each membrane module in each stage. Preferably, washing is performed.
In this case, if the backwashing cycles overlap, which stage of the membrane module should be prioritized for backwashing is set in advance, and the timer is used to sequentially execute the backwashing operation of each stage of the membrane module. Is preferred.
【0033】なお、逆洗時間は、任意に設定できるが、
通常、数秒〜数十秒程度であり、また、逆洗頻度は数分
〜数時間毎である。The backwashing time can be set arbitrarily.
Usually, it is about several seconds to several tens of seconds, and the frequency of backwashing is every few minutes to several hours.
【0034】[0034]
【実施例】以下に実験例、実施例及び比較例を挙げて本
発明をより具体的に説明する。The present invention will be described below more specifically with reference to experimental examples, examples and comparative examples.
【0035】実験例1 膜面積0.036m2 のMF膜モジュールを2本用い、
脈動流による膜の損傷状況を確認する実験を行った。Experimental Example 1 Two MF membrane modules having a membrane area of 0.036 m 2 were used.
An experiment was conducted to confirm the state of membrane damage caused by pulsating flow.
【0036】一方の膜モジュールには2m/sの連続通
水(脈動流なし)で、また、他方の膜モジュールには、
人工的に脈動流を起こすべく、2m/sの通水1〜15
分毎に、流量を半減して1m/sとする通水を5秒間行
う周期的な通水を行い、それぞれ表2に示す試験水を表
2に示す時間通水した。One of the membrane modules has a continuous flow of 2 m / s (no pulsating flow), and the other has a
In order to artificially generate a pulsating flow, water flow of 2 m / s 1 to 15
Every minute, the water flow was halved, the water flow was reduced to 1 m / s, and the periodic water flow was performed for 5 seconds, and the test water shown in Table 2 was passed for the time shown in Table 2.
【0037】通水後、膜面を観察すると共に撮影した写
真から、膜全体の面積に対する孔の見える部分の面積の
割合を開孔率として求め、結果を表2に示した。なお、
通水試験前の新膜の開孔率は33%であった。After the passage of water, the membrane surface was observed and photographed, and the ratio of the area of the visible hole to the area of the entire membrane was determined as the aperture ratio, and the results are shown in Table 2. In addition,
The porosity of the new membrane before the water flow test was 33%.
【0038】[0038]
【表2】 [Table 2]
【0039】表2より、特に、粉末活性炭や石膏粒子と
いった粒子を含む原水、とりわけ、硬度の高い石膏粒子
を含む原水を通水すると脈動流により膜が著しく損傷
し、膜の濾過面に形成されている網目構造の孔がつぶれ
てしまうことがわかる。As can be seen from Table 2, when the raw water containing particles such as powdered activated carbon and gypsum particles, particularly the raw water containing gypsum particles having high hardness, is passed through, the membrane is significantly damaged by the pulsating flow and formed on the filtration surface of the membrane. It can be seen that the holes of the network structure collapsed.
【0040】実施例1,比較例1 図2に示す如く、2本のMF膜モジュール(有効膜面積
2m2 ,チューブ膜を41本装着,長さ3m)を直列に
接続した膜濾過装置を用いて排煙脱硫排水をポリ塩化ア
ルミニウムで凝集処理した水の通水実験を行った。Example 1 and Comparative Example 1 As shown in FIG. 2, a membrane filtration device was used in which two MF membrane modules (effective membrane area 2 m 2 , 41 tube membranes were mounted, and length 3 m) were connected in series. A flue gas desulfurization effluent was subjected to a water flow experiment in which water was subjected to coagulation treatment with polyaluminum chloride.
【0041】図2において、図1に示す部材と同一機能
を奏する部材には同一符号を付してある。なお、逆洗タ
ンクWのエア抜き弁や水位計は図示を省略してある。P
1 ,P2 ,P3 ,P4 ,P5 は圧力計、F1 ,F2 ,F
3 は流量計である。In FIG. 2, members having the same functions as those shown in FIG. 1 are denoted by the same reference numerals. The air vent valve and water level gauge of the backwash tank W are not shown. P
1 , P 2 , P 3 , P 4 , P 5 are pressure gauges, F 1 , F 2 , F
3 is a flow meter.
【0042】各自動弁の開閉を表3に示す通りとしたと
きの各部の圧力及び流量を表4に示した。Table 4 shows the pressure and flow rate of each part when the automatic valves were opened and closed as shown in Table 3.
【0043】なお、逆洗は、同時逆洗の場合、15分毎
に10秒間、順次逆洗の場合、M11では15分毎に10
秒間、M21では17分毎に10秒間行った。Incidentally, backwash, the case of simultaneous backwashing, 10 seconds every 15 minutes, in the case of sequentially backwashing, every 15 minutes in M 11 10
Seconds, was performed for 10 seconds every 17 minutes in M 21.
【0044】[0044]
【表3】 [Table 3]
【0045】[0045]
【表4】 [Table 4]
【0046】表3,4より次のことがわかる。即ち、逆
洗時に濃縮水の一部を排出しない比較例1では、給水流
量F1 が採水時7.15m3 /hから逆洗時4.2〜
4.5m3 /hに減少し、給水入口側圧力P1 が、採水
時0.2MPa程度から逆洗時0.24〜0.31MP
aに急増した。これに対して、逆洗時に濃縮水の一部を
排出する実施例1では給水流量F1 が採水時7.0m3
/hから逆洗時6.7〜6.95m3 /hとわずかに減
少し、給水入口側圧力P1 は採水時0.196MPaか
ら逆洗時0.184〜0.195MPaとわずかに変動
したのみであった。The following can be seen from Tables 3 and 4. That is, in Comparative Example 1 does not discharge a part of the concentrated water during backwashing, during backwash feed water flow F 1 from water sampling at 7.15m 3 / h 4.2~
Decreased to 4.5 m 3 / h, the feed water inlet pressure P 1 is, 0.24~0.31MP during backwashing from about water sampling at 0.2MPa
a. In contrast, Example 1 in the feed water flow rate F 1 is water sampling at 7.0 m 3 for discharging a part of the concentrated water during backwashing
/ Decreased slightly with backwash time 6.7~6.95m 3 / h from h, the feed water inlet pressure P 1 is slightly varies the backwashing time 0.184~0.195MPa from water sampling at 0.196MPa I just did.
【0047】実施例2,比較例2 膜モジュールを1本のみ用いて、実施例1及び比較例1
とそれぞれ同様に通水試験を行ったところ、採水時及び
逆洗時の給水流量及び給水圧力はそれぞれ表5に示す通
りとなり、膜モジュールが1本の場合でも、濃縮水排出
用の自動弁の開閉を行わない比較例2では1年以上の運
転で膜の損傷が認められたが、濃縮水排出用の自動弁を
設け、逆洗時に濃縮水を排出する本発明によれば、給水
流量、給水圧力の変動幅を小さくして、膜の損傷を防止
することができた。Example 2 and Comparative Example 2 Example 1 and Comparative Example 1 were performed using only one membrane module.
When the water flow test was performed in the same manner as above, the water supply flow rate and water supply pressure at the time of water sampling and backwashing were as shown in Table 5, respectively. Even when one membrane module was used, the automatic valve for discharging concentrated water was used. In Comparative Example 2 in which the opening / closing operation was not performed, the membrane was damaged after one year or more of operation. However, according to the present invention, an automatic valve for discharging concentrated water was provided, and concentrated water was discharged during backwashing. In addition, it was possible to prevent the membrane from being damaged by reducing the fluctuation width of the water supply pressure.
【0048】[0048]
【表5】 [Table 5]
【0049】[0049]
【発明の効果】以上詳述した通り、本発明の膜濾過装置
では、原水の通水を継続しながら間欠的に逆洗を行う場
合において、膜の損傷の原因となる原水の脈動流が防止
され、長期に亘り安定な連続運転を行うことができる。As described above in detail, the membrane filtration device of the present invention prevents the pulsating flow of raw water that causes damage to the membrane when intermittent backwashing is performed while continuing the flow of raw water. Thus, stable continuous operation can be performed over a long period of time.
【図1】本発明の膜濾過装置の実施の形態を示す系統図
である。FIG. 1 is a system diagram showing an embodiment of a membrane filtration device of the present invention.
【図2】実施例で用いた膜濾過装置を示す系統図であ
る。FIG. 2 is a system diagram showing a membrane filtration device used in Examples.
M1 ,M2 ,M3 膜モジュール群 M11,M12,M13,M21,M22,M23,M31,M32,M
33 膜モジュール H1 ,H2 ,H3 ,H4 マニホルド V10,V20,V30 逆洗弁 V11,V21,V31 透過水出口弁 V12,V22,V32 濃縮水排出弁 V13,V23,V33 定流量弁 V14,V24,V34 流量調節弁 W 逆洗タンク L 水位計 V40 エア抜き弁 V41 逆洗水水張り弁 VA1,VA2,VA3 遮断弁 VB1,VB2,VB3 調圧弁M 1 , M 2 , M 3 membrane module groups M 11 , M 12 , M 13 , M 21 , M 22 , M 23 , M 31 , M 32 , M
33 membrane module H 1, H 2, H 3 , H 4 manifold V 10, V 20, V 30 backwash valve V 11, V 21, V 31 permeate outlet valve V 12, V 22, V 32 concentrated water discharge valve V 13, V 23, V 33 constant flow valve V 14, V 24, V 34 flow rate control valve W backwash tank L water gauge V 40 air vent valve V 41 backwash water the water filling valve V A1, V A2, V A3 blocking Valve VB1 , VB2 , VB3 pressure regulating valve
───────────────────────────────────────────────────── フロントページの続き (72)発明者 藤田 裕之 宮城県仙台市青葉区一番町三丁目7番1号 東北電力株式会社火力部内 (72)発明者 佐藤 武 東京都新宿区西新宿3丁目4番7号 栗田 工業株式会社内 (72)発明者 近沢 清仁 東京都新宿区西新宿3丁目4番7号 栗田 工業株式会社内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroyuki Fujita 3-1, 1-1 Ichibancho, Aoba-ku, Sendai, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Inventor Takeshi Sato 3-chome Nishishinjuku, Shinjuku-ku, Tokyo 4-7 KURITA INDUSTRY CO., LTD. (72) Inventor Kiyohito Chikazawa 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo KURITA INDUSTRY CO., LTD.
Claims (1)
濾過膜を具備する膜モジュールと、 該膜モジュールの濃縮水側に原水を供給する原水供給管
と、 該濾過膜を透過した透過水を該膜モジュールから取り出
す透過水取出管と、 濃縮水を該膜モジュールから取り出す濃縮水取出管と、 逆洗水を膜モジュールの透過水側に圧入する逆洗水供給
手段とを有し、 原水を供給しつつ間欠的に逆洗水を膜モジュールに圧入
して該濾過膜を逆洗するようにした膜濾過装置におい
て、 濃縮水の一部を排出する排出管が、前記濃縮水取出管か
ら分岐して、或いは、濃縮水取出管とは別に膜モジュー
ルの濃縮水側に接続して設けられ、 逆洗水が膜モジュールに圧入されている間、開状態に制
御される弁が該排出管に設けられていることを特徴とす
る膜濾過装置。1. A membrane module having a filtration membrane that partitions the interior into a concentrated water side and a permeated water side; a raw water supply pipe for supplying raw water to the concentrated water side of the membrane module; It has a permeate extraction pipe for extracting permeated water from the membrane module, a concentrated water extraction pipe for extracting concentrated water from the membrane module, and a backwash water supply means for forcing backwash water into the permeate side of the membrane module. In a membrane filtration device in which backwash water is intermittently pressed into a membrane module while supplying raw water to backwash the filtration membrane, a discharge pipe for discharging a part of the concentrated water is provided with the concentrated water withdrawal. A valve is provided that is branched from the pipe or connected to the concentrated water side of the membrane module separately from the concentrated water discharge pipe, and is controlled to be open while the backwash water is being pressed into the membrane module. Membrane filtration device provided on the discharge pipe .
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JP00853998A JP3997583B2 (en) | 1998-01-20 | 1998-01-20 | Membrane filtration device and membrane filtration method |
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ID=11695969
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005095812A (en) * | 2003-09-26 | 2005-04-14 | Daicen Membrane Systems Ltd | Water purifying device and water purifying method |
JP2006289366A (en) * | 2001-01-31 | 2006-10-26 | Toshiba Corp | Filtering apparatus and power plant |
JP2007229708A (en) * | 2006-02-06 | 2007-09-13 | Univ Nagoya | Filter |
JP2008229577A (en) * | 2007-03-23 | 2008-10-02 | Metawater Co Ltd | Backwash method of membrane separation unit |
JP2009240917A (en) * | 2008-03-31 | 2009-10-22 | Kurita Water Ind Ltd | Method for improving blocking rate of permeable membrane and permeable membrane device |
JP2011194273A (en) * | 2010-03-17 | 2011-10-06 | Miura Co Ltd | Filtration system |
-
1998
- 1998-01-20 JP JP00853998A patent/JP3997583B2/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006289366A (en) * | 2001-01-31 | 2006-10-26 | Toshiba Corp | Filtering apparatus and power plant |
JP4599326B2 (en) * | 2001-01-31 | 2010-12-15 | 株式会社東芝 | Filtration equipment and power plant |
JP2005095812A (en) * | 2003-09-26 | 2005-04-14 | Daicen Membrane Systems Ltd | Water purifying device and water purifying method |
JP2007229708A (en) * | 2006-02-06 | 2007-09-13 | Univ Nagoya | Filter |
JP2008229577A (en) * | 2007-03-23 | 2008-10-02 | Metawater Co Ltd | Backwash method of membrane separation unit |
JP2009240917A (en) * | 2008-03-31 | 2009-10-22 | Kurita Water Ind Ltd | Method for improving blocking rate of permeable membrane and permeable membrane device |
JP2011194273A (en) * | 2010-03-17 | 2011-10-06 | Miura Co Ltd | Filtration system |
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