JPH07185210A - Filtration device - Google Patents

Abstract

PURPOSE:To provide a filtration device having the filtration performance and deaeration performance (particularly for gas of desirable kind) which can keep the stabilized performance for a long time. CONSTITUTION:A filtrate line 6 for discharging filtrate is connected with either one of a first film module 1 or a second film module 2 connected together almost in series by second and third flow path changeover means 8 and 9, while a deaeration line 7 for supplying inactive gas other than the gas to be deaerated is connected with the other of the two film modules to condense raw liquid and remove dissolved gas, and the raw liquid flowing direction to the first and second film modules 1 and 2 are changed over by a first flow path changeover means 5. The connection of the first and second film modules 1 and 2 with the filtrate line 6 and the deaeration line 7 is changed over by the second and third flow path changeover means 8 and 9 to reverse the liquid flowing direction of raw liquid in respective film modules and also to remove impurities adhering to the surfaces of separation films and the like by the deaeration of inactive gas and recover the flowing and separation performances of raw water to the film surfaces.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to liquid beverages, pharmaceuticals,
Liquid products such as cosmetics that require filtration and deoxygenation to remove impurities, concentrate solutes and maintain quality,
The present invention relates to improvement of a filtration device for producing water such as industrial water used for cleaning electronic parts and mechanical parts, chemical production, etc., which requires removal of impurities and deoxidation treatment, and in particular, improvement of backwashing function of the filtration device. It is a thing.

[0002]

2. Description of the Related Art For liquid products such as liquid drinks, pharmaceuticals, cosmetics, etc., where it is necessary to remove impurities and concentrate solutes in the manufacturing process, and for manufacturing electronic parts, precision machine parts, chemicals, etc. When highly pure water such as used industrial water is required, in recent years, it is carried out by a filtration device using various separation membranes such as a microfiltration membrane, an ultrafiltration membrane and a reverse osmosis membrane.

For example, in the case of filtration using a microfiltration membrane (MF membrane), solid particles in a solution of suspended substances, bacteria, etc. can be separated, and sterile filtration of wine, beer, sake, etc.,
It is used for the concentration or clarification of fruit juices, the production of sterile water for medical and pharmaceutical purposes, and the separation of blood plasma. Ultrafiltration membrane (UF membrane) filtration can separate large molecules dissolved in solutions of proteins, enzymes, emulsions, bacteria, viruses, etc., and removes enzymes such as wine, beer and sake. It is used for concentration or clarification of fruit juices, aseptic (virus) water production for medical and pharmaceutical applications, blood filtration, emulsion separation of paints, and paint recovery in the paint industry. By filtration with a reverse osmosis membrane (RO membrane), separation of solvent and solute can be performed almost completely, desalination of seawater, production of ultrapure water for electronic parts (especially semiconductor devices), paper and pulp industry It is used for wastewater treatment, municipal sewage treatment, and production of pure water for diluting dialysate.

Further, when it is necessary to prevent the deterioration of the components in the product or the water which has been filtered or concentrated by the filtration device using the separation membrane as described above, or the water is the work. When it is necessary to prevent problems such as oxidation of the above substances, dissolved gas (in particular, dissolved oxygen which is the main cause of oxidation) may be removed from these liquids. For removing such dissolved gas, vacuum deaeration method, aeration method (gas replacement method), heating deaeration method, chemical deaeration method, etc. are applied. Membrane-type vacuum deaeration method, which is one type, and membrane-type deaeration apparatus, which is a type of aeration method, is frequently used.

The above-mentioned membrane-type vacuum degassing apparatus has
Using a gas permeable membrane that allows only gas to pass through without passing liquid,
Dissolved gas in the liquid to be treated is deposited on the permeate side under reduced pressure through this membrane, and the degassing apparatus by the above-mentioned membrane gas replacement method uses the same gas permeable membrane and through this membrane. The target dissolved gas is removed by blowing a gas other than the gas to be removed into the liquid to be processed and bringing it into direct contact with the liquid to be processed to lower the partial pressure of the gas to be removed in the liquid.

[0006]

As described above, conventionally, when performing filtration or concentration treatment and degassing (mainly deoxygenation), two separate devices, a filtering device and a degassing device, are required. And each installation space was required.

Further, the separation membrane and the gas permeable membrane used in the above-mentioned membrane type filtration device and degassing device are generally formed into a tubular shape, a hollow fiber shape, a pleated shape, or a spiral shape (glue shape). The module is constructed by increasing the effective contact area of the liquid to be treated per volume during filtration or degassing and storing it in a predetermined container in this state. Then, as its usage mode, a so-called cross-flow method in which the liquid to be treated is circulated in parallel to the film surface is adopted, thereby suppressing clogging of the film surface, and maintaining stable film performance, and The film life is being extended. However, even in the above-mentioned filtering device and deaerating device, after a long period of use, clogging still occurs,
It causes deterioration of filtration performance. In particular, in the case of a module using a hollow fiber-shaped or spiral-shaped separation membrane or gas permeable membrane (hereinafter collectively referred to as a membrane), dust is clogged in the inflow gap of the water to be treated at the fixed end of the membrane, and the membrane surface In addition to hindering the flow of the water to be treated, impurities such as Fe, Mn, and Si adhere to the surface of the film, and hinder the filtration performance and gas permeation performance.

In this case, conventionally, the performance of the module has been recovered by reversing the water-passing method in the module or by circulating a chemical in the module to recover the performance, but a satisfactory performance recovery has not been obtained. Is the current situation.
In addition, such cleaning usually needs to be performed after the operation of the apparatus is stopped, which may cause a decrease in operating rate. Further, as described above, when performing filtration or concentration treatment and degassing (mainly deoxygenation), two independent devices, a filtering device and a degassing device, are required, and the membrane in each device has a characteristic. Due to the need to use different ones, there is still no backwashable device that has both functions.

Therefore, an object of the present invention is to provide a filtering device which has both a filtering function and a degassing function (especially for a desired type of gas) and can maintain stable performance for a long period of time.

[0010]

The present invention has been made in view of the above-mentioned problems, and achieves filtration operation and degassing operation with substantially the same type of membrane module by combining the membrane filtration method and the gas replacement method. In addition, the improvement of the backwash function in such an apparatus is achieved by the following configuration.

Specifically, the first and the first housings each containing a separation membrane
A first flow path switching means for connecting the stock solution sides of the second membrane modules in series and switching the stock solution flow direction to these membrane modules is provided, and the stock solution flow direction front side by the switching operation of the first flow path switching means. The second flow path switching means for connecting the permeate side of the membrane module and the filtrate line for discharging the filtrate filtered by the separation membrane are provided, and the raw liquid flow direction downstream stage by the switching operation of the first flow path switching means. The third channel switching means for connecting the permeate side of the membrane module on the side and the aeration line for supplying an inert gas other than the gas to be degassed are further provided, and the first channel switching is further provided. The second flow path switching means is provided for connecting the permeate side of the membrane module, which is the latter side in the stock solution flow direction by the switching operation of the means, and the filtrate line for discharging the filtrate filtered by the separation membrane, and the second flow path switching means is provided. A third flow path switching means is provided for connecting the permeate side of the membrane module, which is on the upstream side in the undiluted solution flow direction by the switching operation of the flow path switching means, and the aeration line for supplying the inert gas other than the gas to be degassed. In addition, the first and second membrane modules containing separation membranes are connected in series between the stock solution line and the processing solution line, and the stock solution flows to these membrane modules. A first flow path switching means for switching the direction is provided, and the permeate side of the membrane module that is on the upstream side in the stock solution flow direction and the stock solution side of the membrane module that is on the downstream side in the stock solution flow direction by the switching operation of the first flow path switching means. A second flow path switching means for connecting the gas flow path and the permeate side of the membrane module which is on the rear side in the raw material flow direction by the switching operation of the first flow path switching means and an inert gas other than the degassing target gas are supplied. Exposure A filtration device which is characterized in that a third flow path switching means for connecting the line.

[0012]

According to the present invention, the first and second membrane modules (1) (2) connected in series are switched by the switching operation of the second flow path switching means (8) and the third flow path switching means (9). ), The filtrate line (6) for discharging the filtrate is selectively connected to one of the membrane modules, and the aeration line (7) for supplying an inert gas other than the gas to be degassed to the other membrane module. Is selectively connected to concentrate the stock solution and remove the dissolved gas in the stock solution. Alternatively, the filtrate line (6) from the membrane module on the upstream side of the stock solution flow direction is changed by the switching operation of the second flow channel switching means (8) and the third flow channel switching means (9). The aeration line (7) that supplies an inert gas other than the gas to be degassed is selectively connected to the membrane module on the downstream side to filter and concentrate the stock solution and to dissolve the dissolved gas in the stock solution. Remove. The first and second membrane modules are operated by operating the first flow path switching means (5).
(1) The first and second membrane modules (1) and (2) are switched by switching the flow direction of the stock solution to the (2) and operating the second flow path switching means (8) and the third flow path switching means (9). By switching the connection status of the filtration line (6) and the aeration line (7), the flow direction of the stock solution in each membrane module (1) (2) is reversed and the fixed end of the separation membrane is clogged with dust, etc. In addition to removing the impurities, impurities and the like adsorbed and attached to the membrane surface of the separation membrane are removed by aeration of an inert gas, and the flow of raw water to the membrane surface and the separation performance are restored.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment showing the basic structure of a filtering device according to the present invention will be described below with reference to FIGS. In the illustrated embodiment, the first and second serially connected
The second membrane module (1) and (2) are provided. The upstream membrane module concentrates the undiluted solution by filtration, and the downstream membrane module concentrates the concentrated undiluted solution in the upstream membrane module by the gas replacement method ( Aeration method) is a form of degassing.

Each of the above-mentioned membrane modules (1) and (2) has a hollow fiber-shaped, spiral-shaped (glue-shaped), and pleated separation membrane inside, and a liquid that has passed through the separation liquid and the undiluted liquid side through which the undiluted liquid flows. It is divided into the permeate side through which the (filtrate) flows. The membrane modules (1) and (2) are connected in series by connecting one ends on the side of the undiluted solution with a connection line (11), and in this state, a supply line for the liquid to be treated (hereinafter referred to as undiluted solution line). ) (3) and the degassing treatment liquid supply line (hereinafter referred to as the treatment liquid line) (4).

Further, the membrane module (1) (2) is provided between each of the other end portions of the membrane modules (1) (2) on the side of the undiluted solution and the undiluted solution line (3) and the treatment solution line (4). The first flow path switching means (5) for switching the flow direction of the stock solution with respect to (4) is interposed. In the present embodiment, the first flow path switching means (5) uses two three-way switching valves (5a) (5b) so that the membrane modules (1) and (2) in series and the stock solution line (3) ) And the processing liquid line (4). In FIG. 1, the first membrane module (1) is placed in the
The state where the membrane module (2) is set to the rear stage side is shown. In FIG. 2 on one side, the second membrane module (2) is set to the front stage side and the first membrane module (1) is set to the rear stage side. Is shown. The first flow path switching means (5) described above is not only a three-way switching valve in this embodiment but also a known four-way switching valve such as an embodiment (second embodiment) shown in FIGS. It is possible to use various types of flow path switching means.

On the permeation side of each of the above membrane modules (1) and (2),
A filtrate derivation line using a separation membrane (hereinafter referred to as a filtrate line) (6) and an inert gas supply line for aeration (hereinafter referred to as an aeration line) (7) are connected to each other, and the filtrate is By the second flow path switching means (8) and the third flow path switching means (9) interposed between the line (6) and the aeration line (7), respectively, The connection state between the filtrate line (6) and the aeration line (7) is switched. That is, as shown in FIG. 1, when the first membrane module (1) is on the front side and the second membrane module (2) is on the rear side, the filtrate line (6) is only on the permeate side of the first membrane module (1). Communication, aeration line (7) is the second membrane module
If the second membrane module (2) is on the front side and the first membrane module (1) is on the rear side as shown in FIG. 2, then the filtrate line (6 ) Is the second
Only communicate with the permeate side of the membrane module (2), aeration line
(7) is switched so as to communicate only with the permeate side of the first membrane module (1).

Incidentally, the inert gas supplied through the aeration line (7) does not change the components in the liquid to be treated (stock solution) in which the gas (gas) to be removed is dissolved. One or more kinds of gases (inert gas) are selected and used as gas for aeration. here,
The above-mentioned inert gas is a gas with a low reactivity, that is, an inert gas in a broad sense, and includes nitrogen, carbon dioxide (carbon dioxide gas) and the like in addition to a rare gas. Further, in obtaining the aeration gas, when the selected inert gas is one type, it is used as it is, and when a plurality of types are used, they are mixed at an appropriate composition ratio. Generally, nitrogen gas and carbon dioxide gas are often used in terms of price and the like. In the illustrated embodiment, the stock solution line (3) is connected to a solution sending pump (10) for sending the stock solution (solution to be treated) under pressure toward the membrane module.

The operation of the filtration device having the above construction will be described below. First, the first, second and third flow path switching means
(5) (8) (9) are switched so that the first membrane module (1) is connected to the front side and the second membrane module (2) is connected to the rear side as shown in FIG. (6) to the permeate side of the first membrane module (1) on the upstream side, and the aeration line (7) to the second side.
Connected to the permeate side of the membrane module (2).

In this state, by means of the liquid delivery pump (10),
When the liquid to be treated (stock solution) is pressure-supplied from the stock solution line (3) to the stock solution side of the first membrane module (1) on the upstream side, this stock solution is fed to the stock solution side of the separation membrane of the first membrane module (1). Separation membrane A part of the solvent in the stock solution, fine particles and solutes exceeding the separation performance of the membrane, flow along the membrane surface, and move to the permeation side through this separation membrane. Then, a part of the solvent, the above-mentioned fine particles and the solute move to the permeate side as the filtrate, and the stock solution which is substantially in a concentrated state is fed from the connection line (11) to the second membrane module (2) on the rear side. The filtrate flowing into the stock solution and separated from the stock solution is discharged to the outside of the system through the filtrate line (6).

After that, the concentrated stock solution that has flowed into the stock solution side of the second membrane module (2) on the subsequent stage is the second membrane module.
The stock solution side of the separation membrane of (2) flows along this separation membrane surface. At this time, since the inert gas for aeration is supplied to the permeate side of the second membrane module (2), the separation membrane is sandwiched between
The partial pressure ratio of gas is different between the raw solution side and the permeate side. Therefore, each gas moves through the separation membrane between the permeate side and the stock solution side so that the partial pressure ratios of the gas are equal on the stock solution side and the permeate side. That is, gases other than the inert gas dissolved in the stock solution move to the permeate side, and the inert gas on the permeate side moves to the stock solution side. Therefore, dissolved oxygen in the stock solution will be removed. At this time, by supplying only the inert gas to the permeate side and keeping the partial pressure of the gas other than the inert gas such as oxygen as zero as possible, the dissolved gas gas other than the inert gas on the raw liquid side is It can be removed until it becomes substantially zero. still,
The pressure on the permeate side of the inert gas at this time is set to be higher than the stock solution pressure on the stock solution side, and such a pressure setting prevents the filtrate from flowing out to the permeate side in the membrane module for aeration on the latter stage side. It can be prevented.

As described above, the concentrated undiluted solution which has been deoxidized by aeration after filtration is sent as a processing solution to a predetermined demand point through the processing solution line (4).

When such a filtration device is continuously used for a long period of time, as described above, the inflow gap of the raw water at the fixed end of the separation membrane in the membrane module is clogged with fine particles such as dust and a part of the solute. In addition to blocking the flow of raw water to the membrane surface,
Fine particles and solutes exceeding the separation performance adhere to the surface of the separation membrane, which impedes the separation performance. In addition, the clogging of the raw water inflow gap at the fixed end of the separation membrane is remarkable at the upstream fixed end of the upstream side membrane module, and hardly at the upstream fixed end of the downstream side membrane module.

Therefore, the first, second and third flow path switching means
(5) (8) (9) are switched so that the first membrane module (1) is connected to the rear side and the second membrane module (2) is connected to the front side as shown in FIG. (6) to the permeate side of the second membrane module (2) on the upstream side, and the aeration line (7) to the first side.
Connected to the permeate side of the membrane module (1). still,
The filtering procedure in this state is the same as that described above, and will be omitted.

In the connection state shown in FIG. 2, the flow direction of the stock solution on the side of the stock solution in each membrane module (1) (2), and the filtrate or the filtrate in the separation membrane in each membrane module (1) (2). The flow direction of the inert gas is opposite to the state shown in FIG.
Therefore, the dust and the like clogging the fixed end of the separation membrane can be removed by circulating the raw water in the opposite direction, and the circulation of the raw water to the membrane surface can be restored. Also, in FIG. 1, the first membrane module connected to the filtrate line (6)
In the state shown in Fig. 2, (1) is connected to the aeration line (7). Therefore, during filtration, the fine particles and solutes attached to or adsorbed on the membrane surface of the separation membrane and exceeding the separation performance are removed by the inert gas flowing from the permeate side toward the stock solution side during the aeration shown in FIG. Due to the pressure, these impurities can also be removed from the separation membrane,
Separation performance is restored.

The above switching timing of the distribution direction is judged by the reduction of the treatment capacity such as the filtration degree of the filtration device and the raw water treatment amount, and the time of switching is determined after the treatment capacity is extremely lowered.
If the flow direction is switched while the processing capacity is slightly lower than the initial value, stable performance can be maintained for a long period of time.

3 and 4 show a second embodiment according to the present invention, which is a more concrete embodiment. still,
In FIGS. 3 and 4, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In addition, the operation in the second embodiment is also the same as in the first embodiment.
Since it is substantially the same as the embodiment described above, redundant description will be omitted and only different points will be described.

In the second embodiment, the first and second
The membrane modules (1) and (2) are arranged substantially parallel to each other to simplify each pipe. That is, the inlet of the raw solution on the side of the raw solution of each membrane module (1) (2), and the outlet of the processing solution on the side of the raw solution are close to each other, and the permeate side of each membrane module (1) (2). Since the connection ports of are also close to each other, the length of each pipe can be shortened. In addition, the first flow path switching means (5) for switching the liquid circulation direction of the stock solution to each of the membrane modules (1) and (2) is performed by one four-way switching valve (5c), whereby the stock solution line (3) and The piping of the processing liquid line (4) is simplified. Further, by arranging each of the membrane modules (1) and (2) so that the flow directions of the stock solutions are both vertical,
It is said that the inert gas supplied to the rear side membrane module enters the raw solution side of the front side membrane module through the connection line (11) and adheres to the raw solution side surface of the separation membrane as bubbles to inhibit the filtration action. Problems can be avoided.

In the second embodiment, the stock solution line is used.
(3) A pre-filter (20) is connected inside to capture dust in advance and prevent it from clogging the inflow gap on the fixed end side of the separation membrane of the membrane modules (1) and (2). In addition, the filter (21) is also connected to the treatment liquid line (4) to capture impurities, dust and the like flowing out from the membrane module after switching the flow paths as described above.

In the first and second embodiments described above, the stock solution is concentrated by filtration in the upstream membrane module, and the concentrated stock solution in the upstream membrane module is replaced by the gas replacement method in the downstream membrane module ( In the present invention, the filtrate filtered by the upstream membrane module is degassed by the gas replacement method (aeration method) in the downstream membrane module. It is also applicable to the case. An application example in this case is shown in FIGS. 5 and 6 as a third embodiment, and will be described below with reference to the drawings. In the following description, in FIGS. 5 and 6, the same components as those in FIGS. 1 and 2 and FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. Further, the operation of the third embodiment is also substantially the same as that of the first embodiment, and therefore the duplicated description will be omitted and only different points will be described.

In the third embodiment, the first and second membrane modules (1) and (2) containing the separation membrane are connected in series between the stock solution line (3) and the treatment solution line (4). And a first flow path switching means (5) for switching the flow direction of the undiluted solution to these membrane modules (1) and (2). And the first and second
The first and second filtrate lines (6a) and (6b) are connected to the permeation sides of the membrane modules (1) and (2), respectively, and the other ends of the first and second filtrate lines (6a) and (6b) are connected. Second and first membrane modules (2) (1) respectively
It is connected to the stock solution side of. This first and second filtrate line
(6a) and (6b) can be selectively opened and closed by the second flow path switching means (8). That is, when the first membrane module (1) is on the upstream side in the stock solution flow direction by the operation of the first flow path switching means (5), the first filtrate line (6a) is opened and the second filtrate line (6a).
When b) is closed and the second membrane module (2) is on the upstream side in the stock solution flow direction, the first filtrate line (6a) is closed and the second filtrate line (6b) is opened.

Further, in the third embodiment, a concentrated liquid line (13) for discharging the concentrated undiluted liquid is provided, and the concentrated liquid line (13) and the undiluted liquid side downstream in the membrane module on the upstream side in the undiluted liquid flow direction. A fourth flow path switching means (14) for selectively connecting the ends is provided. This concentrate line (13) is the fourth
The flow path switching means (14) establishes a connection state with the permeate side of the membrane module that is on the downstream side in the stock solution flow direction, but the fourth flow path switching means (14) is the second flow path switching means (8). Is included as a four-way switching valve (9a), and the second flow path switching means (8) is constituted by the illustrated three-way switching valve (8a) and four-way switching valve (9a). To do. Such flow path switching means may include various known flow path switching means as described above.

In the third embodiment, the filtrate filtrated in the membrane module on the upstream side in the stock solution flow direction is filtered by the first filtrate line (6a) or the second filtrate line (6b) to the undiluted solution of the downstream membrane module. To the permeate side of the membrane module on the latter stage side to introduce an inert gas from the aeration line (7) to remove a predetermined dissolved gas, and to filter it from the treatment liquid line (4). After that, a degassed treatment liquid is obtained. At this time, the concentrated stock solution discharged from the membrane module on the upstream side through the concentrate line (13) may be discharged out of the system, but in order to improve the recovery rate of the filtrate from the stock solution, the stock solution line ( It is preferable to recirculate to the upstream side of the first flow path switching means (5) in 3). That is, in the separation membrane as described above, the filtration (permeation) rate is not so fast, and in order to improve the recovery rate of the filtrate from the stock solution or the concentration rate of the stock solution, the stock solution concentrated by filtration is used as the stock solution line (3 In (), it is returned to the upstream side of the first flow path switching means (5) and reused.
This point is the same in the first and second embodiments.
Further, also in the third embodiment, the first flow path control means
The function and effect when the liquid flow direction of the stock solution is changed by (5) are the same as those in each of the above-described embodiments, and therefore the description thereof will be omitted.

In each of the above-mentioned embodiments, filtration is performed on the upstream side and degassing is performed on the downstream side by the gas replacement method. However, the present invention is not limited to such degassing method, A method may be adopted in which degassing is performed on the side by a gas replacement method and filtration is performed on the downstream side. In the above-mentioned embodiments, the change of such a form is the first flow path switching means.
Switching between (5) and the other sets of flow path switching means (8) (9) (14) can be easily achieved by performing the procedure in the reverse order of the above description.

Further, in each of the above embodiments, when supplying a predetermined inert gas to the membrane module from the aeration line (7), it is performed prior to the supply of the stock solution from the stock solution line (3) to the membrane module. By filling the permeate side and the stock solution side with this inert gas, the degassing performance at the initial stage of the degassing process, that is, the so-called rising characteristic can be improved. At this time, excess inert gas is discharged from the processing liquid line (4).

Specific application fields of the filtration device shown in the above embodiments are as follows. That is, liquid products such as liquid beverages, pharmaceuticals, cosmetics, etc. as described above, which require removal of impurities and concentration of solutes in the manufacturing process, and which are suitable for deoxygenation treatment for maintaining quality. And its production line, high-purity industrial water used for manufacturing electronic parts, precision machine parts, chemicals, etc., to prevent oxidation and corrosion of workpieces, and to prevent oxidation and deterioration of components to improve quality. For example, a water supply line for which deoxidation treatment is suitable for maintaining

Further, in the filtration device according to the present invention, since the gas replacement (aeration) with the inert gas is performed in the membrane module on the front stage side or the rear stage side, the treatment liquid becomes saturated due to the dissolution of the inert gas, Redissolution of oxygen can be effectively prevented.

In the above description, the filtering device is a filtering device for removing dissolved oxygen in the stock solution (or the filtrate). However, the filtering device according to the present invention is not a gas to be removed from the stock solution. The inert gas is replaced with the dissolved gas to remove the dissolved gas to be removed, and the gas to be removed is not limited to oxygen.

Further, in the above embodiments, one membrane module is provided for each of the front and rear stages. However, in the present invention, the number of membrane modules in each stage is plural. May be.

[0042]

The present invention has the above-mentioned structure.
It is possible to easily switch the flow direction of the undiluted solution with respect to the first and second membrane modules, so that not only the fixed end surface of the separation membrane of the membrane module but also the surface of the separation membrane itself can be removed.
It is possible to prevent an increase in pressure loss, a decrease in filtration performance, and a decrease in deaeration performance due to aeration. Furthermore, by periodically switching the flow direction of the stock solution with respect to the first and second membrane modules, it is possible to prevent the above-mentioned troubles due to clogging and adhesion of dirt on the separation membrane of the membrane module. Load on the membrane module can be averaged,
The durability of the entire system can be improved, and stable long-term continuous operation becomes possible.

Further, the filtration device according to the present invention has both a filtration function and a degassing function (especially for a desired type of gas) in one unit, and can maintain stable performance for a long period of time, so that the installation space is small. It is also easy to maintain. Further, since the filtration device according to the present invention performs gas replacement (aeration) with an inert gas in the membrane module on the front stage side or the rear stage side, the treatment liquid is saturated due to the dissolution of the inert gas, Redissolution of the gas of interest can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment according to the present invention.

FIG. 2 is a schematic configuration diagram showing a state in which the flow direction of the stock solution is switched in the first embodiment shown in FIG.

FIG. 3 is a schematic configuration diagram showing a second embodiment according to the present invention.

FIG. 4 is a schematic configuration diagram showing a state in which the flow direction of the stock solution has been switched in the second embodiment shown in FIG.

FIG. 5 is a schematic configuration diagram showing a third embodiment according to the present invention.

6 is a schematic configuration diagram showing a state in which the flow direction of the stock solution has been switched in the third embodiment shown in FIG.

[Explanation of symbols]

 (1) First membrane module (2) Second membrane module (3) Raw liquid line (4) Treatment liquid line (5) First flow path switching means (6) Filtrate line (7) Aeration line (8) Second flow Path switching means (9) Third flow path switching means

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C02F 1/20 A

Claims (3)

[Claims] 1. The first and second membrane modules (1) and (2) containing a separation membrane are connected in series to each other in the undiluted solution side, and the undiluted solution flow direction to these membrane modules (1) and (2) A first flow path switching means (5) for switching between the first side flow path switching means (5) and the permeate side of the membrane module which is the upstream side of the stock solution flow direction by the switching operation of the first flow path switching means (5) and the filtrate filtered by the separation membrane A second flow path switching means (8) is provided to connect with the filtrate line (6) to be drawn out, and the permeation of the membrane module on the downstream side in the stock solution flow direction by the switching operation of the first flow path switching means (5). Side and aeration line (7) that supplies inert gas other than the gas to be degassed
A filtering device comprising a third flow path switching means (9) for connecting with. 2. The undiluted solution side of the first and second membrane modules (1) and (2) containing the separation membranes are connected in series, and the undiluted solution flow direction to these membrane modules (1) and (2). A first flow path switching means (5) for switching between the first side flow path switching means (5) and the permeate side of the membrane module which is the latter side of the raw liquid flow direction by the switching operation of the first flow path switching means (5) and the filtrate filtered by the separation membrane A second flow path switching means (8) for connecting with the filtrate line (6) to be drawn out is provided, and the permeation of the membrane module on the upstream side in the raw liquid flow direction by the switching operation of the first flow path switching means (5). Side and aeration line (7) that supplies inert gas other than the gas to be degassed
A filtering device comprising a third flow path switching means (9) for connecting with. 3. The first and second membrane modules (1) and (2) containing a separation membrane are connected in series between a stock solution line (3) and a treatment solution line (4), The first flow path switching means (5) for switching the flow direction of the undiluted solution to the membrane modules (1) and (2) is provided,
A second connection connecting the filtrate line (6) of the membrane module, which is on the upstream side in the stock solution flow direction by the switching operation of the first flow path switching means (5), and the raw solution side of the membrane module, which is on the downstream side in the stock solution flow direction. The flow path switching means (8) is provided and the first
A third connecting the permeate side of the membrane module, which is the latter side in the stock solution flow direction by the switching operation of the flow path switching means (5), and the aeration line (7) for supplying an inert gas other than the gas to be degassed.
A filtering device comprising a flow path switching means (9).