JP2004237281A - Membrane separation apparatus, and state detecction method for the apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drastically improve the detection precision and reliability of a membrane separation apparatus by efficiently detecting whether a membrane module is damaged or not by a simple system in a short time. <P>SOLUTION: This membrane separation apparatus for obtaining a permeated liquid or a concentrated liquid by using the membrane module divided into an original liquid chamber and a permeated liquid chamber by a separation membrane is provided with a means for discharging the liquid in the first chamber being any of the original liquid chamber and the permeated liquid chamber, a means for reducing the pressure of the second chamber being the other of the original liquid chamber and the permeated liquid chamber by suction and a means for measuring the pressure-reduced state of the second chamber. And the method for detecting the state in the apparatus is provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a membrane separation apparatus for obtaining a permeated liquid permeated through a separation membrane or a concentrated liquid blocked by the separation membrane using a separation membrane such as a microfiltration membrane, an ultrafiltration membrane, or a reverse osmosis membrane, and a state in the apparatus. It relates to the detection method.

  Membrane separation devices using membrane modules such as microfiltration membranes and ultrafiltration membranes are widely used in various industries such as water treatment fields such as desalination of seawater, pure water production and wastewater treatment, and food fields such as wine and fruit juice concentration. Has been adopted. In such a membrane separation device, there is a possibility that troubles such as leakage of the stock solution to the permeate side may occur due to damage to the separation membrane or insufficient sealing of the membrane module. Therefore, in order to prevent the occurrence of these inconveniences, a number of membrane separation devices provided with means for detecting breakage of a separation membrane or a membrane module have been proposed.

For example, in Patent Literature 1 and Patent Literature 2, a membrane separation device provided with a means for detecting a failure of a membrane module by filling a stock solution chamber of a membrane module with a pressurized gas and measuring a change in gas pressure or flow rate. Has been proposed. Patent Document 3 proposes a method in which pressurized air is filled in a stock solution chamber of a membrane module, and bubbles that appear when air leaks into the permeate chamber are detected by an optical sensor.
JP-A-60-94105 JP-A-8-10590 JP 2000-342937 A

  The devices disclosed in Patent Document 1, Patent Document 2, and Patent Document 3 determine communication from a stock solution chamber to a permeate chamber due to a failure of a membrane module with respect to the tightness of the stock solution chamber. In this method, a pressurized gas is charged into a stock solution chamber, and a fluctuation or leakage of the charged gas is detected.

However, these devices have the following practical problems.
First, in the method of detecting the pressure fluctuation of the pressurized gas filled in the undiluted solution chamber, if the gas leakage from the undiluted solution chamber of the membrane module to the permeate chamber is minute, the volume of the pressurized gas must be reduced. In addition, the pressure drop in the stock solution chamber cannot be detected in a short time. In other words, when the membrane separation device is a large-scale device, the number of membrane modules used in the device also increases, so the total volume of the stock solution chamber filled with the pressure gas also increases, and the pressure fluctuation of the pressure gas is detected. In many cases, it is practically impossible to detect the film breakage by performing the operation. In addition, it is possible to divide the membrane module used in a large-scale membrane separation apparatus into a small number of membrane modules and carry out the above-described membrane breakage detection method. It takes a long time to check for damage and many additional facilities are required, which is not practical.

  Second, in the method of detecting the filling flow rate of the pressurized gas filling the undiluted liquid chamber and the leaking gas flow rate to the permeated liquid chamber, gas leakage from the undiluted liquid chamber to the permeated liquid chamber of the membrane module is very small, and When the volume of the gas is large, it is necessary to supply a pressurized gas instantaneously at a high pressure in order to detect the minute flow rate of the gas, and further, it is necessary to provide a flow rate measuring means capable of accurately measuring the minute flow rate of the gas. Become. In addition, in this method, the air supply pressure is applied to the bubble point of the separation membrane used (air pressure is applied from one side of the separation membrane wetted by a liquid such as water, and bubbles are observed on the opposite side of the membrane. Considering that the pressure must be equal to or less than the minimum pressure) and that the difference between the supply flow rate of the gas and the flow rate of the leaked gas becomes extremely large, it is determined that it cannot be realized in an actual apparatus.

  Therefore, an object of the present invention is to enable a simple system to efficiently detect the state of a membrane module, particularly whether or not the membrane module is damaged, in a short time even in a large-scale membrane separation apparatus, thereby greatly increasing the accuracy and reliability of the detection. It is an object of the present invention to provide a membrane separation device which can be improved and a method for detecting a state of the device.

  In order to solve the above-mentioned problems, a membrane separation device according to the present invention provides a membrane separation device that obtains a permeate or a concentrate using a membrane module partitioned into a stock solution chamber and a permeate chamber by a separation membrane. Means for discharging the liquid in the first liquid chamber of one of the liquid chamber and the permeated liquid chamber, means for reducing the pressure in the second liquid chamber by suction, and means for measuring the reduced pressure state of the second liquid chamber Are provided.

  In this membrane separation device, it is also possible to adopt a structure in which means for pressurizing the first liquid chamber from which the liquid is discharged with gas is provided.

  Further, in the above-mentioned membrane separation apparatus, a plurality of membrane modules may be provided, and the pressure reduction state measuring means of the second liquid chamber may be provided for each of the membrane modules.

  In addition, a plurality of membrane modules are provided, and the second liquid chamber of each membrane module is communicated with the second merging pipe, and the second merging pipe is connected to the decompression inside the second merging pipe. The means for measuring the state may be provided as a common measuring means for measuring the reduced pressure state of the second liquid chamber of each membrane module.

  Further, a plurality of membrane modules are provided, a first liquid chamber of each membrane module is connected to a first merging pipe, and a first liquid chamber of each membrane module is connected via the first merging pipe. The liquid in the liquid chamber may be discharged.

  The state detection method in the membrane separation device according to the present invention is a state detection method in a membrane separation device that obtains a permeate or a concentrate using a membrane module partitioned into a stock solution chamber and a permeate chamber by a separation membrane. After discharging the liquid in the first liquid chamber of one of the undiluted liquid chamber and the permeated liquid chamber, the pressure in the other second liquid chamber is reduced by suction, and the reduced pressure state of the second liquid chamber is measured. .

  In this state detection method, after the liquid in the first liquid chamber is discharged, the first liquid chamber may be pressurized with gas and the second liquid chamber may be depressurized by suction.

  Further, in the above-described state detection method, when a plurality of membrane modules are provided in the membrane separation device, it is possible to measure the reduced pressure state of the second liquid chamber for each membrane module.

  Further, when a plurality of membrane modules are provided in the membrane separation device, and the second liquid chambers of the respective membrane modules are communicated with the second merging pipes, the pressure in the second merging pipes is reduced. Is measured, the decompressed state of the second liquid chamber of each membrane module can be measured as their overall state.

  Further, when a plurality of membrane modules are provided in the membrane separation device, and the first liquid chamber of each membrane module is communicated with a first merge pipe, the first liquid chamber is connected via the first merge pipe. Alternatively, the liquid in the first liquid chamber of each membrane module may be discharged.

  In such an apparatus and method, when the undiluted solution is water, after the undiluted solution or the permeated liquid in the undiluted liquid chamber or the permeated liquid chamber is discharged, that is, after the liquid in the first liquid chamber is discharged, the permeation pressure is reduced by suction. It is preferable that the pressure of the liquid chamber or the undiluted liquid chamber, that is, the reduced pressure of the second liquid chamber is in a range of −20 kPa to −90 kPa with respect to a reference pressure (for example, atmospheric pressure) when suction is not performed. If the pressure is reduced to a pressure lower than −90 kPa, water vapor may be generated, and when the water vapor is generated, the liquid cannot be substantially sucked. If the degree of pressure reduction is smaller than -20 kPa, the difference from the reference pressure is too small, so that it may be difficult to measure the reduced pressure state or its change.

  The present inventors are most concerned when the membrane module and other peripheral parts in the membrane separation device are damaged, that the stock solution side and the permeate solution side are not separated, that is, the stock solution chamber and the permeate solution chamber are connected. Therefore, various investigations were attempted with a focus on the fact that the soundness of the membrane separation device can be determined by checking the presence or absence of the communication.

  As a result, the undiluted liquid in the undiluted liquid chamber or the permeated liquid in the permeated liquid chamber is discharged from the membrane module (the liquid in the first liquid chamber of the membrane module is discharged), and the permeated liquid chamber or the undiluted liquid chamber (second liquid chamber) is discharged. The present invention has been completed by finding that it is possible to easily and accurately detect breakage of the membrane module and defective sealing by confirming the degree of pressure reduction or the change in the degree of pressure reduction by suction.

  That is, in the present invention, the liquid in the first liquid chamber is discharged to be empty, and the second liquid chamber is reduced in pressure by suction in a state where the liquid is substantially full. If the first liquid chamber and the second liquid chamber are more or less in communication with each other due to breakage of the membrane or insufficient sealing of the membrane module, the pressure in the second liquid chamber cannot be reduced to a predetermined pressure by suction or even if the pressure can be reduced. Even if it does, the reduced pressure cannot be maintained. Since the pressure in the second liquid chamber is reduced by suction in a state where the liquid is substantially filled in the second liquid chamber, the result of whether or not the pressure in the second liquid chamber can be reduced to a predetermined pressure is determined. Alternatively, the result of whether the reduced pressure can be maintained even if the reduced pressure can be measured very quickly and with high sensitivity. As a result, even in a large-scale membrane separation apparatus, the state of the membrane module, particularly the presence or absence of breakage thereof, can be efficiently detected in a short time, and the accuracy and reliability of the detection are greatly improved.

The present invention has the following advantages.
First, when depressurizing the stock solution chamber or the permeate chamber of the membrane module by suction, the pressure that can be suctioned is at most about -100 kPa, so the pressure difference applied to the separation membrane depends on the precision that is generally used in water treatment. It is unlikely that the pressure exceeds the bubble point of the filtration membrane or the ultrafiltration membrane, and there is no fear of applying unnecessary high pressure to the membrane module.

  Second, in the case of ordinary water treatment, the concentrated liquid or the permeated liquid chamber of the membrane module is full of concentrated water or permeated water, and the water is an incompressible fluid. Even if the volume of the liquid chamber to be suctioned and decompressed becomes large, a large-scale decompression device and ancillary equipment are not required. For the same reason, the pressure can be reduced irrespective of the volume of the liquid chamber to be suction-depressurized. Therefore, regardless of the size of the membrane separation device, the predetermined detection can be performed with high sensitivity and high accuracy.

  Third, if the membrane module is damaged, the stock solution chamber and the permeate chamber communicate with each other, and pressure reduction to a predetermined pressure can hardly be achieved. The difference from the case where there is no breakage can be clearly and easily determined.

  Fourth, since the sensitivity for determining the presence / absence of membrane breakage is high, even in the case of a membrane separation device using a plurality of membrane modules, for example, a decompression state measuring means (for example, a vacuum pressure gauge) is provided for each membrane module. ), It is possible to easily identify a damaged membrane module by performing a single decompression operation.

  ADVANTAGE OF THE INVENTION According to the membrane separation apparatus and the state detection method in the apparatus according to the present invention, it is possible to detect breakage of a membrane module and insufficient sealing with high sensitivity and accuracy in a short time with a simple operation, and a plurality of membrane modules can be detected. Even in a large-scale membrane filtration device that uses, it is possible to detect breakage of the membrane module without increasing the number of additional facilities, and to provide a highly reliable membrane separation device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a membrane separation device according to a first embodiment of the present invention. This membrane separation device includes a raw water tank 2 into which raw water 1 is introduced, a raw water supply pump 3, a membrane module 5, a permeated water tank 10, a water trap 15, and a vacuum pump 16 as a means for reducing the pressure by suction. Have. The inside of the membrane module 5 is partitioned into a raw water chamber 7 and a permeated water chamber 8 by, for example, a hollow fiber or tubular separation membrane 6.

  During normal operation of the membrane separation device, the raw water 1 is introduced into the raw water tank 2 and supplied to the membrane module 5 using the raw water pump 3. The permeated water that has passed through the separation membrane 6 passes through the permeated water chamber 8 and is stored in the permeated water tank 10. The raw water 1 that has not passed through the separation membrane 6 is returned to the raw water supply pump 3 through the raw water chamber 7. During normal operation, the valves 4, 9 and 11 are open, and the valves 12, 13 and 14 are closed. When the raw water 1 that has not passed through the separation membrane 6 is obtained as concentrated water, it can be sent to a concentrated water tank (not shown) without returning it to the raw water supply pump 3.

  When detecting breakage of the membrane module 5 (or insufficient sealing of the membrane module 5), the raw water supply pump 3 is stopped, and the valves 4, 9 and 11 are closed. Next, the valve 12 and the valve 13 are opened, and first, the raw water in the raw water chamber 7 as the first liquid chamber is discharged. Next, the valve 12 is closed and the valve 14 is opened to start the vacuum pump 16, and the pressure from the permeated water chamber 8 to the water trap 15 is reduced by suction. At this time, if there is no communication between the raw water chamber 7 and the permeated water chamber 8 (that is, if there is no communication due to the breakage of the separation membrane 6), the pressure from the permeated water chamber 8 to the water trap 15 is reduced in vacuum, The reduced pressure state can be confirmed by the vacuum pressure gauge 17 as a measuring means. If there is a defect such as breakage of the separation membrane 6 in the membrane module 5 and the raw water chamber 7 and the permeated water chamber 8 communicate with each other, the pressure from the permeated water chamber 8 to the water trap 15 is not reduced, or even temporarily. Even if the pressure is reduced, the degree of pressure reduction sharply decreases, and the vacuum pressure gauge 17 detects an incomplete state of pressure reduction.

  FIG. 2 shows a membrane separation device according to a second embodiment of the present invention. In the present embodiment, a total of eight membrane modules 5 are provided, and two membrane modules 5 are provided as one unit. Although the first unit 27 and the second unit 28 can simultaneously pass water, valves 4, 29, 11, 12 and valves 22, 23, 24, 25 are provided so that they can be independent for each unit. Only the number of membrane modules and the number of valves are different from those of the apparatus shown in FIG. However, a vacuum pressure gauge is installed on the permeated water pipe of each of the membrane modules, and vacuum pressure gauges 18, 19, 20, and 21 for the first unit 27 are illustrated as representatives. With these vacuum pressure gauges 18, 19, 20, and 21, the reduced pressure state of the permeated water chamber 8 can be measured for each membrane module. Further, the permeated water pipe from the permeated water chamber 8 of each membrane module 5 is communicated with the second merging pipe 31, and as in the configuration shown in FIG. A vacuum pressure gauge 17 is provided between the second merging pipe portion, in this embodiment, the water trap 15 and the vacuum pump 16. Further, when the liquid is discharged from the raw water chamber 7 of each membrane module 5 via the valve 12 or 25, the liquid can be discharged through the first junction pipe 32 connected to each raw water chamber 7.

  During normal operation of this membrane separation device, raw water 1 is introduced into raw water tank 2 and supplied to each membrane module 5 of membrane units 27 and 28 using raw water pump 3. The permeated water that has passed through the separation membrane 6 passes through the permeated water chamber 8, merges in each membrane unit, and is stored in the permeated water tank 10. The raw water that has not passed through the separation membrane merges in each membrane unit via the raw water chamber 7 and is returned to the front of the raw water pump. During normal operation, the valves 4, 29, 11, 22, 23, and 24 and the valve 9 are open, and the valves 12, 13, 14, 25, and 26 are closed.

  The operation of detecting breakage of the membrane module and the like is performed in each of the membrane units 27 and 28. To describe the case of detecting breakage of the membrane module of the first membrane unit 27, first, the raw water supply pump 3 is stopped, and the valves 4, 29, and 11 are closed. Next, the valves 12 and 13 are opened to discharge the raw water in the raw water chamber 7. Next, the valves 9, 12, and 23 are closed, the valves 14 and 29 are opened, the vacuum pump 16 is started, and the pressure from the permeated water chamber 8 to the water trap 15 is reduced. At this time, if there is no communication between the raw water chamber 7 and the permeated water chamber 8 in each module in the unit, the pressure from the permeated water chamber 8 to the water trap 15 is reduced in pressure, and the reduced pressure state is confirmed by the vacuum manometer 17. it can. If there is a defect such as breakage of the separation membrane in the membrane module and the raw water chamber 7 and the permeated water chamber 8 communicate with each other, the pressure from the permeated water chamber 8 to the water trap 15 is not reduced by vacuum. An incomplete state of decompression is confirmed. The soundness of the entire membrane unit, including the malfunction of the membrane module, can be confirmed by the above operations.

  Further, by checking the individual vacuum pressure gauges 18, 19, 20, and 21 installed in each membrane module, it is possible to detect which membrane module has communication between the raw water chamber 7 and the permeated water chamber 8.

  In the case of performing the film damage detection operation of the second film unit 28, the above operation may be performed on the second film unit 28. Further, in the apparatus of the above embodiment, when performing the membrane breakage detection operation, the raw water supply pump is stopped to stop the operation of both units. However, the raw water supply pump is not stopped, and the first membrane unit 27 is not stopped. It is also possible to adopt a configuration in which the second membrane unit 28 can be operated even when is performing a damage detection operation.

  The membrane separation apparatus shown in FIGS. 1 and 2 is an example of the embodiment of the present invention, and the present invention is not limited to the illustrated one as long as it does not exceed the gist.

  Although not shown in the above embodiment, the present invention is also applicable to a device in which a backwash pump is provided in the membrane separation device so that the backwash of the membrane module can be performed.

  In the apparatus of the above embodiment, an example in which the raw water in the raw water chamber 7 is discharged and the pressure in the permeated water chamber 8 is reduced has been described. In the present invention, the permeated water in the permeated water chamber is discharged, and the raw water chamber side is discharged. The pressure may be reduced and the reduced pressure state of the raw water chamber may be measured.

  In the apparatus of the above embodiment, a vacuum pump is shown as a depressurizing means for the permeated water chamber. However, the depressurizing means is not limited to a vacuum pump, such as a water pump or an aspirator. Means are applicable.

  Further, in the above-described embodiment, an apparatus having one membrane module and an apparatus having eight membrane modules and two units have been exemplified. However, the present invention can be applied to an apparatus using a plurality of units and a plurality of units other than the examples.

  The shape of the membrane module includes a hollow fiber membrane, a tubular membrane, a flat membrane, a spiral membrane, and the like, and the present invention is applicable to any shape. The present invention is preferably applied to a module of a type.

  In the present invention, as a material of the separation membrane, polyacrylonitrile, polysulfone, sulfonated polysulfone, polyether sulfone, polyvinylidene fluoride, polypropylene, polyethylene, polyamide, polyvinyl alcohol, cellulose acetate, ceramics, various metals such as separation membrane Any material used can be applied to the membrane module.

  In addition, the present invention can be applied to various types of membranes, such as microfiltration membranes, ultrafiltration membranes, and reverse osmosis membranes. It is preferably applied to a separation membrane having a separation hole diameter of several μm.

  In the present invention, the state detection in the membrane separation device is performed by measuring the depressurized state of the second liquid chamber. However, the total pressure difference (the pressure of the first liquid chamber minus the pressure of the first liquid chamber that can maintain the depressurized state in a normal state). 2) is determined by the confidentiality of the apparatus, the material of the separation membrane, the pore diameter, and the like. The present invention is characterized in that soundness is determined by setting the second liquid chamber to a reduced pressure state. However, as described above, the degree of reduced pressure of the second liquid chamber is limited. Therefore, for example, when the pore diameter of the separation membrane is small and the degree of membrane breakage is extremely small (for example, when a pinhole is formed in the membrane, and the pinhole is extremely small [of course, larger than the pore diameter of the separation membrane]). In the case where it is difficult to determine the soundness unless the total pressure difference is large, as in the case of), the first liquid chamber from which the liquid has been discharged is pressurized with gas (for example, air), and simultaneously with the pressurization, Alternatively, it is also possible to reduce the pressure in the second liquid chamber after the pressurization and measure the reduced pressure state. In this case, a part of the total pressure difference required for the soundness determination is compensated for by the decompression of the second liquid chamber, which is a feature of the present invention. The degree of pressurization is small. Further, if the operation of discharging the liquid in the first liquid chamber and the operation of supplying the pressurized gas are performed at least partially by overlapping, the supply of the pressurized gas is performed when the liquid in the first liquid chamber is discharged. Then, the liquid can be pushed out from the first liquid chamber, and advantages such as shortening of the liquid discharging time can be expected.

  As a device configuration, for example, as shown in FIG. 3 showing a membrane separation device according to a third embodiment of the present invention, compared with the device according to the first embodiment shown in FIG. As means for pressurizing the room with gas, for example, a compressor 33, an air storage layer 34, and a valve 35 for filling the raw water chamber 7 of the membrane module 5 with pressurized air may be added. Other configurations can be substantially the same as the first embodiment shown in FIG. With the membrane separation device having such a configuration, as described above, an appropriate total pressure difference can be easily ensured even when the total pressure difference is small and it is difficult to determine the soundness only by depressurizing the second liquid chamber. , And the soundness can be easily determined.

  The liquid to be treated (stock solution) in the present invention is not particularly limited, and the present invention provides various types of water treatment such as river water, lake water, groundwater, industrial water, and tap water, various wastewater treatments, and recovery of valuable resources. It can be applied to pure water and pyrogen-free water production.

  The operation of the membrane separation device includes a constant flow filtration and a constant pressure filtration, and the present invention can be applied to any operation. However, a constant flow filtration operation is generally performed.

  In addition, as the number of operations of the separation membrane damage detection increases, the safety and reliability of the device increase, but the frequency is preferably about once a day to once a month, and is preferably. It is performed once a day to once a week.

  In the membrane separation apparatus of the present invention, it is also possible to perform membrane separation after adding a coagulant to the water to be treated, and the coagulation chemicals include inorganic materials such as polyaluminum chloride, sulfate sulfate, iron chloride, and iron sulfate. In addition to the coagulant, an organic polymer coagulant such as acrylamide can be used, and various coagulants and pH adjusting chemicals such as acids and alkalis can also be used as additive chemicals.

Hereinafter, the present invention will be described more specifically based on examples.
Examples 1 and 2
The operation was carried out for the purpose of confirming the sensitivity at the time of breakage of the membrane module using an apparatus equivalent to the apparatus of FIG. 1 described in the embodiment of the present invention. An FE-10UF module (manufactured by Daisen Membrane Systems) was used as the membrane module. A vacuum pump was used as a pressure reducing means for the permeated water chamber.

  As Example 1, a module for intentionally cutting one hollow fiber of the FE-10 module was used, and as Example 2, a new module of FE-10 was used to perform a test for detecting a film breakage.

Comparative Examples 1 and 2
Further, as a comparative example, a conventional method of pressurizing the undiluted solution side of the membrane module 5 using the apparatus shown in FIG. 4 and detecting a broken state of the membrane module in a state where the pressure was maintained was subjected to a comparative test following the example. As Comparative Example 1, a module in which one hollow fiber of the FE-10 module was intentionally cut was tested, and as Comparative Example 2, a new FE-10 module was tested.

  In the apparatus of FIG. 4, the device configuration and the detection method used for detecting the damage of the membrane module 5 are different from the method shown in FIG. 1 and are as follows. A compressor 41, an air reservoir 42, and a valve 43 are provided for the purpose of filling the raw water chamber 7 of the membrane module 5 with pressurized air, and a pressure gauge 44 is provided for checking the pressure holding state of the raw water chamber 7. .

  Also in the apparatus of FIG. 4, at the time of a normal membrane filtration operation, the same operation as in the apparatus of FIG. 1 is performed. The following steps are performed when film damage is detected. First, the raw water supply pump 3 is stopped. Next, the valves 12, 13 are opened and the valves 4, 9, 11, 14, 43 are closed, and the raw water in the raw water chamber 7 is discharged. Next, the valve 43 is opened, and the valves 4, 9, 11, 12, 13, and 14 are closed, and pressurized air is sent into the raw water chamber 7 to an arbitrary set pressure. Thereafter, the valve 43 is closed and the valve 14 is opened to maintain the pressure for an arbitrary set time. At this time, if the membrane module 5 is not damaged, there is almost no change in the value of the pressure gauge 44. If there is any abnormality in the membrane module 5, pressurized air passes through the separation membrane 6 and passes through the permeated water chamber. 8. Leakage to the valve 14 side, and a decrease in the value of the pressure gauge 44 is observed.

  In Comparative Examples 1 and 2, the pressurized air pressure was 100 kPa, and the pressure holding time was 10 minutes. FIG. 5 shows the state of maintaining the vacuum pressure and the state of maintaining the pressure in the permeated water chamber in Examples 1 and 2 and Comparative Examples 1 and 2.

  When there is no abnormality in the membrane module, the reduced pressure state hardly changes in 10 minutes, and when one hollow fiber in the membrane module is cut, the reduced pressure state is broken in about 1 minute. This was confirmed from Examples 1 and 2. Therefore, it was confirmed that by applying the membrane separation device of the present invention and the state detection method in the device, it is possible to efficiently detect the abnormality of the membrane module in a short time, and with high sensitivity and accuracy.

  In Comparative Examples 1 and 2, even after 10 minutes of pressurization holding time, the difference in pressure change between the case where the membrane module had an abnormality and the case where there was no abnormality was small, and the apparatus and method of the present invention were compared with the conventional method. It was confirmed to be extremely excellent in detecting an abnormality of the membrane module and high in reliability.

  INDUSTRIAL APPLICABILITY The membrane separation device and the state detection method in the device according to the present invention can be applied to any application that requires obtaining a permeate that has passed through a separation membrane or a concentrated solution that has been blocked by the separation membrane.

FIG. 2 is an equipment system diagram of the membrane separation device according to the first embodiment of the present invention. It is a system diagram of a membrane separation device concerning a 2nd embodiment of the present invention. It is a system diagram of a membrane separation device concerning a 3rd embodiment of the present invention. FIG. 4 is an equipment system diagram of a membrane separation device used in a comparative example. FIG. 9 is a graph showing the relationship between the liquid chamber pressure and the pressure holding time, showing the results of the examples and comparative examples.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Raw water 2 Raw water tank 3 Raw water supply pump 4, 9, 11, 12, 13, 14, 22, 23, 24, 25, 26, 29, 35, 43 Valve 5 Membrane module 6 Separation membrane 7 Raw water chamber 8 Permeated water chamber DESCRIPTION OF SYMBOLS 10 Permeated water tank 15 Water trap 16 Vacuum pump 17, 18, 19, 20, 21 Vacuum pressure gauge 31 Second merging pipe 32 First merging pipe 33, 41 Compressor 34, 42 Air reservoir 44 Pressure gauge

Claims (10)

  In a membrane separation device for obtaining a permeate or a concentrate using a membrane module partitioned into a stock solution chamber and a permeate solution chamber by a separation membrane, the liquid in one of the first solution chamber of the stock solution chamber and the permeate solution chamber is used. And a means for reducing the pressure in the second liquid chamber by suction, and a means for measuring the reduced pressure state of the second liquid chamber.   The membrane separation device according to claim 1, further comprising a unit configured to pressurize the first liquid chamber from which the liquid has been discharged with a gas.   3. The membrane separation device according to claim 1, wherein a plurality of the membrane modules are provided, and a reduced pressure state measuring unit for the second liquid chamber is provided for each of the membrane modules. 4.   A plurality of the membrane modules are provided, and the second liquid chambers of each of the membrane modules are connected to a second merging pipe, and the second merging pipe is connected to a decompressed gas in the second merging pipe. The membrane separation device according to any one of claims 1 to 3, wherein the means for measuring a state is provided as a common measurement means for measuring a reduced pressure state of the second liquid chamber of each membrane module.   A plurality of the membrane modules are provided, and the first liquid chamber of each of the membrane modules is connected to a first merging pipe, and the first liquid chamber of each membrane module is connected to the first merging pipe via the first merging pipe. The membrane separation device according to claim 1, wherein the liquid in the liquid chamber is discharged.   A method for detecting a state in a membrane separation apparatus for obtaining a permeate or a concentrate using a membrane module partitioned into a stock solution chamber and a permeate solution chamber by a separation membrane, wherein a method for detecting a permeate solution or a permeate solution chamber is provided. A method for detecting a state in a membrane separation device, comprising: discharging a liquid in a first liquid chamber, reducing the pressure in a second liquid chamber by suction, and measuring a reduced pressure state of the second liquid chamber.   7. The state in the membrane separation apparatus according to claim 6, wherein after discharging the liquid in the first liquid chamber, the first liquid chamber is pressurized with gas and the pressure in the second liquid chamber is reduced by suction. Detection method.   8. The method according to claim 6, wherein a plurality of membrane modules are provided in the membrane separation device, and a reduced pressure state of the second liquid chamber is measured for each of the membrane modules. 9.   The membrane separation device is provided with a plurality of membrane modules, and the second liquid chamber of each membrane module is connected to a second merging pipe, and the pressure in the second merging pipe is reduced. The method for detecting a state in a membrane separation device according to any one of claims 6 to 8, wherein by measuring, the reduced pressure state of the second liquid chamber of each membrane module is measured as an overall state thereof.   The membrane separation device is provided with a plurality of membrane modules, and the first liquid chamber of each membrane module is connected to a first merging pipe, and each of the first liquid chambers is connected via the first merging pipe. The state detecting method in the membrane separation device according to claim 6, wherein the liquid in the first liquid chamber of the membrane module is discharged.

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