JP6253546B2 - Reverse osmosis membrane module and reverse osmosis membrane storage method - Google Patents

Description

  The present invention relates to a reverse osmosis membrane storage method and a reverse osmosis membrane module capable of realizing the storage method.

  A reverse osmosis membrane is used for desalinating seawater and producing pure water. The reverse osmosis membrane is used in a state of being housed in a module through which liquid is passed. In order to prevent deterioration in the performance of the reverse osmosis membrane, the reverse osmosis membrane may be stored in a wet state when not in use. However, in a wet state, there is a risk that bacteria will propagate on the surface of the reverse osmosis membrane or in the module, and the performance of the reverse osmosis membrane may be reduced.

  Patent Documents 1 and 2 disclose storing the separation membrane in a preservation solution in order to prevent a decrease in the performance of the separation membrane such as a reverse osmosis membrane. Examples of the preservation solution include a solution containing a component (drug) such as formaldehyde, sodium hypochlorite, sodium bisulfite, benzoic acid, benzoate, or hydrogen peroxide.

  Patent Document 3 discloses that the semipermeable membrane is treated with a polyhydric alcohol and then dried at a temperature of 5 ° C to 70 ° C in order to prevent a decrease in the performance of the semipermeable membrane. The dried semipermeable membrane is stored in a dry state for a long time.

JP 2000-157850 A JP 2007-63222 A JP 58-156307 A

  When the reverse osmosis membrane is stored in a preservation solution, the active ingredient of the drug in the preservation solution is deactivated over time. When the drug is deactivated, bacteria may propagate on the surface of the reverse osmosis membrane or in the module, thereby reducing the performance of the reverse osmosis membrane.

  When the reverse osmosis membrane is stored in a dry state, the reverse osmosis membrane may become wet depending on the surrounding environment even when not in use. For example, a dry reverse osmosis membrane is stored in a container, but when air flows into the container from the outside, the reverse osmosis membrane becomes wet due to moisture in the air. If the reverse osmosis membrane is dried again after becoming wet once, the performance of the reverse osmosis membrane may be reduced. In addition, when the reverse osmosis membrane is in a wet state, there is a possibility that bacteria may propagate on the surface of the reverse osmosis membrane or in the module.

  Therefore, it is desired to provide an improved reverse osmosis membrane storage method and a reverse osmosis membrane module capable of realizing the storage method.

The reverse osmosis membrane module in one embodiment is a cylindrical vessel that is configured to be hermetically sealed and has a space that accommodates the reverse osmosis membrane. The liquid flows in when the liquid is processed, and the liquid that has passed through the reverse osmosis membrane flows A vessel in which no liquid is introduced when not in use, a pressure reducing means for maintaining the gauge pressure in the sealed vessel in a range of −5 kPa to −30 kPa, and a pressure detector for detecting the pressure in the sealed vessel , Have

In one embodiment, the separation membrane storage method is a cylindrical vessel having a space for accommodating a reverse osmosis membrane, in which liquid flows in during liquid processing, liquid that permeates through the reverse osmosis membrane flows out, and when not in use. a step of housing the reverse osmosis membrane in a vessel where the liquid is not introduced, the steps of sealing the space containing the reverse osmosis membrane, maintaining a gauge pressure of a hermetically sealed vessel in the range of -5kPa~-30kPa Detecting the pressure in the sealed vessel .
In the present specification, “reverse osmosis membrane” should be understood in a broad sense, and includes a so-called “nanofiltration membrane”.

  According to the present invention, it is possible to detect whether or not gas has flowed into the container containing the reverse osmosis membrane from the outside by reducing the pressure in the container and detecting the pressure in the container.

It is a schematic diagram which shows schematic structure of the reverse osmosis membrane module which concerns on 1st Embodiment. It is a flowchart of the storage method of the reverse osmosis membrane which concerns on one Embodiment. It is a schematic diagram which shows schematic structure of the reverse osmosis membrane module which concerns on 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of the reverse osmosis membrane module according to the first embodiment. The reverse osmosis membrane module 10 includes a container 20 having a space 21 for accommodating the reverse osmosis membrane 12. In FIG. 1, the container 20 is illustrated in a transparent manner so that the internal configuration of the container 20 can be understood.

  The container 20 may be comprised from the cylindrical vessel. The container 20 may have an inflow pipe 22, a first outflow pipe 24, and a second outflow pipe 26. The reverse osmosis membrane 12 may be wound around the outer peripheral surface of the liquid collection pipe 28. An opening is formed in the portion of the liquid collection pipe 28 where the reverse osmosis membrane 12 is wound. The liquid that has passed through the reverse osmosis membrane 12 flows into the liquid collection pipe 28 through this opening. In this embodiment, the reverse osmosis membrane module includes three reverse osmosis membranes 12. The liquid collection pipe 28 around which the reverse osmosis membrane 12 is wound communicates with the liquid collection pipe 28 around which the reverse osmosis membrane 12 is wound via a connector 29. Furthermore, the most downstream liquid collection pipe 28 (the rightmost liquid collection pipe in FIG. 1) communicates with the first outflow pipe 24.

  The inflow pipe 22 allows liquid (raw water) to flow into the container 20. The liquid that has passed through the reverse osmosis membrane 12 in the container 20 flows into the liquid collection tube 28. The liquid that has flowed into the liquid collection pipe 28 flows out of the container 20 through the first outflow pipe 24. The liquid that does not flow into the liquid collection pipe 28 flows out of the container 20 through the second outflow pipe 26.

  In the reverse osmosis membrane module 10 shown in FIG. 1, the container 20 contains three reverse osmosis membranes 12. The liquid collection pipe 28 extends long in one direction, and each reverse osmosis membrane 12 is wound around each liquid collection pipe 28. Not only this example but the container 20 should just be comprised so that at least one reverse osmosis membrane 12 can be accommodated. In addition, it is preferable that the reverse osmosis membrane 12 accommodated in the container 20 is a thing of the state by which the drying process was carried out.

  Valves 32, 34, and 36 are provided on the inflow pipe 22, the first outflow pipe 24, and the second outflow pipe 26, respectively. By closing all the valves 32, 34, and 36, the space 21 in the container 20 is maintained in a sealed state.

  The reverse osmosis membrane module 10 includes a decompression unit 40 that reduces the atmospheric pressure in the container 20 containing the reverse osmosis membrane, and a pressure detector 50 that detects the pressure (atmospheric pressure) in the container 20. The decompression means 40 may have any configuration as long as the inside of the container 20 can be decompressed. As an example, as shown in FIG. 1, the decompression means 40 includes a gas suction means 42 that sucks the gas in the container 20, and a gas check valve 44 that prevents a backflow of gas from the gas suction means 42 to the container 20. , May be included. An example of the gas suction means 42 is an air suction pump. The inside of the container 20 can be decompressed by sucking the gas in the container 20 with all the valves 32, 34, and 36 closed.

  In the example shown in FIG. 1, the decompression means 40 is connected to the second outflow pipe 26 between the container 20 and the valve 36. Instead of this, the decompression means 40 may be connected to the inflow pipe 22 or the first outflow pipe 24. The decompression means 40 may be provided at an arbitrary position as long as the inside of the container 20 can be decompressed.

  The pressure detector 50 may be provided at an arbitrary position as long as the pressure in the container 20 can be detected. It is preferable that the pressure detector 50 detects the pressure in the container 20 constantly or at predetermined time intervals at least when the reverse osmosis membrane module is not used. Here, when the reverse osmosis membrane module 10 is not used, no liquid is introduced into the container 20, and the valves 32, 34, and 36 are closed.

  The reverse osmosis membrane module 10 preferably has a notification device 52 that notifies the abnormality of the pressure value in the container 20. The alarm 52 may include a buzzer that emits sound, a lamp that emits light, or both. In addition, the alarm device 52 may include a wireless device that emits radio waves of an abnormal signal in order to notify the monitoring center at a position away from the reverse osmosis membrane module 10 of the abnormality.

  During use of the reverse osmosis membrane module 10, that is, during water treatment, the valves 32, 34, and 36 are opened. The raw water is introduced into the container 20 through the inflow pipe 22. A part of the liquid introduced into the container 20 passes through the reverse osmosis membrane 12 and flows into the liquid collection tube 28. The liquid that has flowed into the liquid collection pipe 28 is discharged to the outside through the first outflow pipe 24. The other part (concentrated water or turbid waste water) of the liquid flowing into the container 20 is discharged outside through the second outlet pipe 26 without flowing into the liquid collection pipe 28.

  Next, an example of a reverse osmosis membrane storage method will be described with reference to FIG. First, the reverse osmosis membrane 12 is accommodated in the container 20 of the reverse osmosis membrane module 10, and the space 21 in which the reverse osmosis membrane 12 is accommodated is sealed (step S1). The reverse osmosis membrane 12 accommodated in the container 20 is preferably a dried membrane. Moreover, the film | membrane processed with the polyhydric alcohol before the drying process may be sufficient as needed. Examples of commercially available reverse osmosis membranes that have been previously dried include GE Corporation: HWSRO8040RE, or Unjin Chemical Corporation RE8040-SHN. When the reverse osmosis membrane 12 is accommodated in the container 20, all the valves 32, 34, and 36 of the reverse osmosis membrane module 10 are kept closed.

  Next, the inside of the container 20 is depressurized while the space 21 containing the reverse osmosis membrane 12 is sealed (step S2). The decompression in the container 20 can be performed by the decompression means 40. During storage of the reverse osmosis membrane 12, the gauge pressure in the container 20 is preferably in the range of −30 kPa to −5 kPa. From the viewpoint of the pressure resistance of the reverse osmosis membrane 12, the lower limit of the gauge pressure in the container 20 is preferably −30 kPa. Further, from the viewpoint of maintaining the dry state of the reverse osmosis membrane 12, the gauge pressure in the container 20 is preferably set to -5 kPa or less.

  Next, the pressure (atmospheric pressure) in the container 20 is detected (step S3). It is preferable to detect the pressure in the container 20 constantly or at predetermined time intervals. The pressure in the container 20 can be detected by the pressure detector 50. Furthermore, this storage method may include a step of notifying when the gauge pressure in the container 20 is out of a predetermined range, here, out of the range of −30 kPa to −5 kPa.

  An increase in the atmospheric pressure in the decompressed container 20 means an inflow of air into the container 20 from the outside. When air flows into the container 20, the reverse osmosis membrane 12 becomes wet due to moisture in the air. In the method described above, the inflow of air from the outside into the container 20 can be detected by reducing the pressure inside the container 20 and detecting the pressure in the container 20.

  When the pressure in the container 20 is set to atmospheric pressure, the pressure in the container 20 remains maintained at atmospheric pressure even if gas flows into the container from the outside. Therefore, when the pressure in the container 20 is atmospheric pressure, it cannot be determined whether the container 20 is reliably sealed. Therefore, it is preferable to make the inside of the container 20 into a reduced pressure state. Further, the upper limit value of the gauge pressure in the container 20 is preferably −5 kPa so that the pressure detector 50 can reliably detect whether or not the reduced pressure in the container 20 is maintained.

  Further, by notifying when the gauge pressure in the container 20 is outside the predetermined range, the user or the monitoring staff is informed that the space 21 for storing the reverse osmosis membrane 12 is in an inappropriate state. Can do. Thus, before the reverse osmosis membrane 12 becomes wetter than moisture in the air, the user or the monitor can take some measures.

  It is preferable that this reverse osmosis membrane storage method is executed from the time of manufacturing the reverse osmosis membrane to before the first use of the reverse osmosis membrane. Moreover, this reverse osmosis membrane storage method can be implemented using the reverse osmosis membrane module 10 described above. In this case, there is an advantage that the reverse osmosis membrane 12 can be stored for a long time in a dry state with the unused reverse osmosis membrane 12 placed in the container 20 of the reverse osmosis membrane module.

  In some cases, when the gauge pressure in the container 20 falls outside a predetermined range, the decompression means 40 may be automatically controlled so that the gauge pressure in the container 20 falls within the predetermined range. Such automatic control can be realized by feeding back the detection signal of the pressure detector 50 to the control means for controlling the decompression means 40.

  In the present embodiment, the method for storing the reverse osmosis membrane 12 using the reverse osmosis membrane module 10 has been described. However, the reverse osmosis membrane storage method of the present invention is not limited to the container 20 of the reverse osmosis membrane module 10 and can be carried out using any container that can seal the internal space.

  Next, the reverse osmosis membrane module according to the second embodiment will be described with reference to FIG. The reverse osmosis membrane module 60 according to the second embodiment includes a plurality of containers 20 having a space 21 in which the reverse osmosis membrane 12 is accommodated. In FIG. 3, the container 20 is illustrated in a perspective manner so that the internal configuration of the container 20 can be understood. The configuration of each container 20 is the same as the configuration of the container of the reverse osmosis membrane module according to the first embodiment.

  The inflow pipe 22 into which the liquid flows into the container 20 has branch paths 22a to 22d, and communicates with each container 20 via the branch paths 22a to 22d. The first outflow pipe 24 has branch paths 24a to 24d. The branch paths 24 a to 24 d of the first outflow pipe 24 are each in communication with a liquid collection pipe 28 around which the downstream reverse osmosis membrane 12 in each container 20 is wound. The second outflow pipe 26 has branch paths 26a to 26d. The branch paths 26 a to 26 d of the second outflow pipe 26 are connected to the respective containers 20. Thus, each container 20 of the reverse osmosis membrane module 60 is connected in parallel.

  The reverse osmosis membrane module 60 may have a common decompression means 40, a common pressure detector 50, and a common alarm 52 for the plurality of containers 20. In the state where all the valves 32, 34, and 36 are closed, the spaces in the respective containers 20 are connected. Therefore, the space in each container 20 can be decompressed by the common decompression means 40. Similarly, the pressure in each container 20 can be detected by the common pressure detector 50.

  The reverse osmosis membrane module 60 according to the second embodiment has an advantage that it is not necessary to provide the decompression means 40, the pressure detector 50, and the alarm 52 for each container 20 that accommodates the reverse osmosis membrane 12.

Example 1
A flat membrane sample was prepared by cutting a commercially available reverse osmosis membrane (manufactured by GE: HWSRO8040RE) into a size of 5 cm × 5 cm after being treated with polyhydric alcohol and dried. This sample was accommodated in a stainless steel sealed container. The gauge pressure in the sealed container was maintained at −15 kPa using an air suction pump.

  First, this sealed container was left in a space at a temperature of 40 ° C. and a humidity of 80% for 1 hour. Thereafter, the temperature in the space in which the sealed container was installed was set to 5 ° C. and left in that state for 1 hour. After that, again, the space in which the sealed container was installed was left for 1 hour with the temperature set at 40 ° C. Such a cycle was repeated 300 times.

  Then, the sample was taken out from the sealed container, and the moisture content of the reverse osmosis membrane was measured using a moisture content measuring device (manufactured by A & D: Moisture Analyzer). Here, when the weight of the sample is “W0” and the weight of the sample after drying in the moisture content measuring device is “W”, the moisture content is defined by “(W0−W) / W0 × 100%”. The

(Example 2)
Using the same sample as in Example 1, the same experiment as in Example 1 was performed. However, in Example 2, the gauge pressure in the sealed container was maintained at -5 kPa. The other experimental conditions are the same as in Example 1.

(Comparative Example 1)
Using the same sample as in Example 1, the same experiment as in Example 1 was performed. However, in Comparative Example 1, the gauge pressure in the sealed container was maintained at -1 kPa. The other experimental conditions are the same as in Example 1.

(Comparative Example 2)
Using the same sample as in Example 1, the same experiment as in Example 1 was performed. However, in Comparative Example 2, the stainless steel container is not sealed and is in an open state. Therefore, in Comparative Example 2, the gauge pressure in the container is 0 KPa. The other experimental conditions are the same as in Example 1.

  Table 1 below shows the moisture content of the reverse osmosis membrane in a new state, the moisture content of the reverse osmosis membrane according to the example after the test, and the moisture content of the reverse osmosis membrane according to the comparative example after the test. Is shown. Table 1 also shows the gauge pressure values in the containers in the comparative examples and the examples.

  The reverse osmosis membranes according to Comparative Examples 1 and 2 were wetter than the new reverse osmosis membranes. On the other hand, the reverse osmosis membranes according to Examples 1 and 2 maintained a dry state as much as a new reverse osmosis membrane. Therefore, from the viewpoint of maintaining the dry state of the reverse osmosis membrane, the gauge pressure in the container is preferably set to −5 kPa or less. Thereby, the storage method of the reverse osmosis membrane of this invention can store a reverse osmosis membrane in a dry state over a long period of time.

  The preferred embodiments and examples of the present invention have been presented and described in detail above, but the present invention is not limited to the above-described embodiments and examples, and various changes and modifications can be made without departing from the gist. Please understand that this is possible.

10, 60 Reverse Osmosis Membrane Module 12 Reverse Osmosis Membrane 20 Container 21 Space 22 Inflow Pipe 24 First Outflow Pipe 26 Second Outflow Pipe 28 Liquid Collection Pipe 32 Valve 34 Valve 36 Valve 40 Depressurization Means 50 Pressure Detector 52 Alarm

Claims (7)

A cylindrical vessel that is configured to be hermetically sealed and has a space for accommodating a reverse osmosis membrane. The liquid flows in when processing the liquid, the liquid that permeates the reverse osmosis membrane flows out, and the liquid flows when not in use. Vessel not introduced ,
Pressure reducing means for maintaining the gauge pressure in the sealed vessel in a range of -5 kPa to -30 kPa,
A reverse osmosis membrane module, comprising: a pressure detector for detecting a pressure in the sealed vessel . The reverse osmosis membrane module according to claim 1, further comprising a notification device that notifies when the gauge pressure in the vessel is out of a range of −5 kPa to −30 kPa. The decompression means comprises a gas suction means for sucking the gas in the vessel, including a gas check valve to prevent backflow of gas into the vessel from the gas suction means, according to claim 1 or 2 Reverse osmosis membrane module. A reverse osmosis membrane housed in the vessel ;
An inlet tube for flowing liquid into the vessel,
A collecting tube into which the liquid that has passed through the reverse osmosis membrane flows,
A first outflow pipe communicating with the liquid collection pipe and allowing the liquid flowing into the liquid collection pipe to flow out of the vessel;
Having a second outlet pipe for discharging the liquid that is flowing into the liquid collection tube from the vessel, the reverse osmosis membrane module according to any one of claims 1 to 3. In a cylindrical vessel having a space for accommodating a reverse osmosis membrane, the liquid flows in when processing the liquid, the liquid that permeates the reverse osmosis membrane flows out, and the liquid is not introduced when not in use . housing the dried treated reverse osmosis membrane, comprising the steps of sealing between pre Kisora,
Containing the reverse osmosis membrane and maintaining the gauge pressure in the sealed vessel in a range of −5 kPa to −30 kPa;
Detecting the pressure in the sealed vessel , and storing the reverse osmosis membrane. The storage method of a reverse osmosis membrane according to claim 5, further comprising a step of notifying when the gauge pressure in the vessel is out of the range of -5 kPa to -30 kPa. The method for storing a reverse osmosis membrane according to claim 5 or 6, wherein the pressure in the vessel is detected at all times or at a predetermined time interval at least when the reverse osmosis membrane is not used.

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