JP2008006393A - Decarbonation device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decarbonation device and method which enable the excellent production of pure water by causing no mixture of gas, such as air, into permeated through a decarbonation membrane. <P>SOLUTION: The decarbonation device B which is connected between a reverse osmosis membrane device A and an ion exchange resin cylinder C, and removes carbon dioxide gas 4a in the permeate 4 passing through the reverse osmosis membrane device A to send the permeate 4 to the ion exchange resin cylinder C comprises the decarbonation membrane B3, a check valve V1 installed upstream of the decarbonation membrane B3 to prevent the backflow of the permeate 4, and a relief valve V2 installed downstream of the check valve V1 to keep degassed water 5 at a positive pressure state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decarboxylation device and a decarboxylation method, and in particular, in a pure water production process using a reverse osmosis membrane device or an ion exchange device, decarboxylation for degassing carbon dioxide gas in permeated water after permeation of the reverse osmosis membrane device. The present invention relates to an apparatus and a decarboxylation method.

  An ion exchange apparatus is used for a pure water production apparatus that produces pure water from raw water such as industrial water. The ion exchange apparatus has an ion exchange resin. By passing raw water through the ion exchange resin, impurity ions in the raw water are removed, and purified water (pure water) having high purity is obtained.

  However, if raw water is passed directly through the ion exchange device, the load on the ion exchange resin becomes excessive, and regeneration and exchange of the ion exchange resin must be performed frequently. Therefore, in a pure water production apparatus, a reverse osmosis membrane device is disposed upstream of an ion exchange device.

  The reverse osmosis membrane apparatus has a reverse osmosis membrane, and salts, fine particles, organic compounds, etc. in raw water can be removed by this reverse osmosis membrane. Therefore, the load of the ion exchange resin can be reduced, and the frequency of regeneration and replacement of the ion exchange resin can be reduced. In this way, pure water with high purity can be obtained by disposing the reverse osmosis membrane device in the former stage and the ion exchange device in the latter stage to purify the raw water.

  In this application, the treated water before flowing into the pure water production apparatus (before permeation of the reverse osmosis membrane) is the raw water, the treated water after permeation of the reverse osmosis membrane device is the permeated water, and the treated water after passing through the ion exchange device. Is called pure water.

  However, when carbon dioxide is contained in the raw water, this reverse osmosis membrane device cannot degas the carbon dioxide. When the permeated water containing carbon dioxide gas reaches the ion exchange device, the load on the ion exchange resin increases. Therefore, in general, a decarboxylation device is connected between the reverse osmosis membrane device and the ion exchange device to degas the carbon dioxide in the permeated water.

  The decarboxylation device has a decarbonation membrane through which gas can pass. For example, permeate passes through one membrane surface of the decarboxylation membrane and counterflows gas such as air along the other membrane surface. The carbon dioxide gas in the permeated water is released into the gas through the decarbonation film. As a result, the carbon dioxide in the permeated water is degassed, the load on the ion exchange resin is reduced, and pure water with higher purity can be obtained. In the present application, the permeated water that has passed through decarboxylation and degassed is referred to as degassed water.

  FIG. 9 shows an example of a conventional pure water production apparatus 100 configured to include a reverse osmosis membrane apparatus 101, a decarboxylation apparatus 102, and an ion exchange apparatus 103. The raw water pressurized and sent by the RO pump 104 passes through the reverse osmosis membrane 105 of the reverse osmosis membrane device 101 and is sent to the subsequent decarboxylation device 102. Carbon dioxide gas in the permeated water sent to the decarboxylation device 102 is degassed through the decarbonation film 106, and the degassed water is further sent to the ion exchange device 103 at the subsequent stage. The deaerated water passes through an ion exchange resin (not shown) in the ion exchange device 103 to become pure water, and is used for various purposes.

The raw water concentrated in the reverse osmosis membrane device 101 is drained through a drain pipe 107. Further, a gas such as air is supplied to the decarboxylation device 102 by a gas supply device 108, and the gas and the permeated water are in contact with the front and back of the decarbonation film 106. As an example of such a pure water production apparatus using a decarboxylation apparatus, there are those disclosed in Patent Documents 1 and 2, for example.
JP 2001-121151 A JP 2003-80036 A

  However, since the decarbonation film 106 allows gas to pass therethrough, if the permeated water in contact with the decarbonation film 106 has a negative pressure, the gas is mixed into the permeated water.

  For example, when the raw water pressurized water supply RO pump 104 is stopped and the pure water production process is terminated, the permeated water after permeation of the reverse osmosis membrane 105 flows back upstream through the reverse osmosis membrane 105 due to the action of osmotic pressure. This causes a so-called suck back phenomenon. Then, the permeated water near the decarbonation film 106 becomes a negative pressure, and gas is mixed into the permeated water through the decarbonation film 106.

  In addition, for example, when the ion exchange device 103 connected downstream of the decarboxylation device 102 is installed at a lower position and there is a difference in head height between the two, the decarboxylation device 102 and the ion are also used after the pure water production process is completed. A so-called siphon phenomenon occurs in which degassed water in the pipe connected to the exchange device 103 flows out to the ion exchange device 103 side. Then, the permeated water near the decarbonation film 106 becomes a negative pressure, and gas is mixed into the permeated water through the decarbonation film 106.

  As described above, if a gas is mixed in the permeated water, when the pure water production process is restarted, the gas is sent to the ion exchange device 103 connected to the downstream side of the decarboxylation device 102, and inside it, It accumulates. If it does so, there existed a problem that the load to ion exchange resin became large and ion exchange efficiency fell, and that pure water production efficiency fell by extension. In particular, when the ion exchange apparatus 103 is an ion exchange resin cylinder in which the ion exchange resin is hermetically sealed, the ion exchange apparatus 103 is installed on the upper lid portion of the ion exchange resin cylinder in order to evacuate the gas accumulated inside. It was necessary to periodically perform the work of loosening the gas vent screw and venting the gas from the cylinder.

  The present invention has been made in view of the above circumstances, and a decarboxylation apparatus capable of producing pure water satisfactorily without mixing a gas such as air into the permeated water through the decarbonation membrane. It is an exemplary problem to provide a decarboxylation method.

  In order to solve the above-described problems, a decarboxylation device as an exemplary aspect of the present invention is connected between a reverse osmosis membrane device and an ion exchange device, and carbon dioxide gas in permeated water that has permeated the reverse osmosis membrane device. A decarboxylation device for degassing and feeding degassed water toward the ion exchange device, a decarbonation membrane, and a backflow prevention means provided on the upstream side of the decarboxylation membrane to prevent a reverse flow of permeate, And a positive pressure holding means that is provided downstream of the backflow prevention means and holds the deaerated water in a positive pressure state.

  Since the backflow prevention means provided on the upstream side of the decarbonation membrane prevents the backflow of permeate, the permeate on the downstream side of the backflow prevention means does not backflow even if a suck back phenomenon occurs in the reverse osmosis membrane device. Therefore, the permeated water in the vicinity of the decarbonation film does not become negative pressure, and gas does not enter the permeated water through the decarbonation film.

  In addition, since the positive pressure holding means is provided on the downstream side of the backflow prevention means, the deaerated water in the connection pipe between the decarboxylation device and the ion exchange device flows out to the ion exchange device side due to siphon phenomenon, for example. However, the permeated water near the decarbonation membrane does not become negative pressure. Therefore, no gas is mixed into the permeated water through the decarbonation membrane.

  The check valve may be a check valve. For example, by using a check valve (model: CKF3R) manufactured by T-L Buoy Co., Ltd. as a backflow prevention valve, the backflow of permeate can be prevented easily and inexpensively. Further, the positive pressure holding means may be a relief valve provided on the downstream side of the accumulator or the decarbonation film.

  For example, by providing a bladder type accumulator (model: AL) manufactured by NOK Corporation on the upstream side or the downstream side in the vicinity of the decarboxylation device, the permeated water in the vicinity of the decarbonation membrane can be maintained in a positive pressure state easily and inexpensively. Therefore, even if the siphon phenomenon occurs, no gas is mixed into the permeated water through the decarbonation film. Further, for example, by providing a relief valve (model: Type 715) manufactured by Sekisui Chemical Co., Ltd. on the downstream side of the decarbonation film, adverse effects due to the siphon phenomenon can be eliminated.

  The backflow prevention means is a first on-off valve that can be controlled to open and close, the positive pressure holding means is a second on-off valve that is provided on the downstream side of the decarbonation film and can be controlled to open and close, and a reverse osmosis membrane When stopping the supply of raw water to the apparatus, before closing the second on-off valve before closing the first on-off valve, and before the pressure of the raw water in the reverse osmosis membrane apparatus becomes 0.02 MPa or less A valve opening / closing control device for closing the first opening / closing valve may be further included.

  By controlling the first and second on-off valves provided respectively upstream and downstream of the decarbonation membrane by the valve on / off control device, it is possible to prevent gas from entering the permeated water through the decarbonation membrane. . For example, the pressure of the permeate near the decarbonation membrane decreases with the stop of the supply of raw water to the reverse osmosis membrane device (end of the pure water production process), but first before the first on-off valve is closed. By closing the second on-off valve, it is possible to ensure a positive pressure state of the permeated water in the vicinity of the decarboxylation film while eliminating an adverse effect due to the siphon phenomenon. Then, by closing the first on-off valve before the raw water is finally released to atmospheric pressure, the positive pressure state of the permeated water in the vicinity of the decarbonation film is secured while eliminating the adverse effects due to the suck back phenomenon. can do.

  When the pressure of the raw water is 0.006 MPa or less, in many cases, gas is mixed into the permeated water through the decarbonation film 106. Therefore, more specifically, it is desirable to close the first on-off valve before the pressure of raw water becomes 0.006 MPa or less. In the present application, “pressure” of raw water means “differential pressure from atmospheric pressure”.

  A decarboxylation method according to another exemplary aspect of the present invention includes a decarboxylation device connected between a reverse osmosis membrane device and an ion exchange device and having a decarbonation membrane. A decarbonation method for degassing carbon dioxide gas, the step of preventing backflow of permeate by a backflow prevention means provided upstream of the decarbonation membrane when stopping the supply of raw water to the reverse osmosis membrane device; And maintaining the deaerated water in a positive pressure state by a positive pressure holding means provided on the downstream side of the backflow prevention means.

  Since the backflow prevention means provided on the upstream side of the decarbonation membrane prevents the backflow of permeate, the permeate on the downstream side of the backflow prevention means does not backflow even if a suck back phenomenon occurs in the reverse osmosis membrane device. Therefore, the permeated water in the vicinity of the decarbonation film does not become negative pressure, and gas does not enter the permeated water through the decarbonation film.

  In addition, since the positive pressure holding means is provided on the downstream side of the backflow prevention means, the deaerated water in the connection pipe between the decarboxylation device and the ion exchange device flows out to the ion exchange device side due to siphon phenomenon, for example. However, the permeated water near the decarbonation membrane does not become negative pressure. Therefore, no gas is mixed into the permeated water through the decarbonation membrane.

  According to still another exemplary aspect of the present invention, there is provided a decarboxylation method in which permeated water permeated through a reverse osmosis membrane device by a decarboxylation device connected between the reverse osmosis membrane device and an ion exchange device and having the decarbonation membrane. In which the carbon dioxide gas is degassed, and when the supply of raw water to the reverse osmosis membrane device is stopped, the first on-off valve provided upstream of the decarbonation membrane is closed before closing. A step of closing the second on-off valve provided on the downstream side of the decarbonation film, and a step of closing the first on-off valve before the permeated water pressure becomes 0.006 MPa or less.

  For example, the pressure of the permeate near the decarbonation membrane decreases with the stop of the supply of raw water to the reverse osmosis membrane device (end of the pure water production process), but first before the first on-off valve is closed. By closing the second on-off valve provided on the downstream side of the decarbonation film, the positive pressure state of the permeated water in the vicinity of the decarbonation film can be ensured while eliminating the adverse effects due to the siphon phenomenon. Then, by closing the first on-off valve provided on the upstream side of the decarbonation membrane before the permeated water pressure finally drops to atmospheric pressure, decarboxylation while eliminating the adverse effects due to the suck back phenomenon. A positive pressure state of permeated water in the vicinity of the membrane can be ensured.

  When the pressure of the permeated water is 0.006 MPa or less, gas is mixed into the permeated water through the decarbonation film. Therefore, more specifically, it is desirable to close the first on-off valve before the pressure of raw water becomes 0.006 MPa or less.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, the vicinity of the decarbonized film can be maintained in a positive pressure state without being adversely affected by the suck back phenomenon or siphon phenomenon. Therefore, pure water can be produced satisfactorily without mixing a gas such as air into the permeated water through the decarbonation film.

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1]
Hereinafter, the pure water manufacturing apparatus S using the decarboxylation apparatus B which concerns on Embodiment 1 of this invention using drawings is demonstrated. FIG. 1 is a schematic block diagram showing the overall configuration of the pure water production apparatus S. The pure water production apparatus S is generally configured by connecting a reverse osmosis membrane apparatus A, a decarbonation apparatus B, and an ion exchange resin cylinder (ion exchange apparatus) C in order from the upstream side.

  The reverse osmosis membrane device A has a reverse osmosis membrane A1 inside, and is for removing salts, fine particles, organic compounds and the like from the raw water 2 fed from the RO pump E for pressurizing the raw water. The permeated water 4 that has permeated the reverse osmosis membrane A1 is sent to the decarboxylation device B through the connection pipe P1.

  A drain pipe A2 is provided on the upstream side of the reverse osmosis membrane device A1 so that it cannot pass through the reverse osmosis membrane A1 and can drain part of the concentrated raw water 2. Further, the RO pump E can be controlled by an inverter circuit E1, and may be capable of preventing sudden pressure changes at the start and stop of water supply.

  The decarbonation apparatus B has a decarbonation vessel B1, a check valve V1 as a backflow prevention means, and a relief valve V2 as a positive pressure holding means, and is connected to the subsequent stage of the reverse osmosis membrane apparatus A. The check valve V1 is provided on the upstream side of the decarboxylation vessel B1, the relief valve V2 is provided on the downstream side of the decarboxylation vessel B1, and the permeated water 4 sent from the connection pipe P1 is added to the check valve V1, The decarbonation vessel B1 and the relief valve V2 are sent to the ion exchange resin cylinder C in the subsequent stage through the connection pipe P4.

  FIG. 2 is a schematic configuration diagram showing an internal configuration of the decarboxylation vessel B1. The decarbonation vessel B1 is generally configured by providing a hollow fiber membrane-like decarbonation membrane B3 inside a generally cylindrical vessel body B2, and the air supplied from the gas supply device D inside the hollow fiber, etc. The gas 6 is aerated in the counterflow direction with the permeated water 4 (that is, from the upper side to the lower side in FIG. 1 from the connection pipe P6 to the connection pipe P7). On the other hand, the permeated water 4 is sent from the connecting pipe P2 to the connecting pipe P3 with the outside of the hollow fiber facing from the bottom to the top in FIG. 1, so that the permeated water 4 and the gas 6 are in contact with the front and back of the decarbonation membrane B3. (Hereinafter, the inside of the hollow fiber through which the gas 6 passes is defined as the inside of the decarbonation membrane B3, and the outside of the hollow fiber through which the permeated water 4 passes is defined as the outside of the decarbonation membrane B3). In this way, the permeated water 4 and the gas 6 are brought into contact with the front and back of the decarbonation film B3, and the carbon dioxide gas 4a in the permeated water 4 is efficiently flown into the gas 6 by causing them to flow countercurrently to each other. It can be degassed.

  The check valve V1 is for preventing the permeated water 4 in the connection pipe P2 from flowing back into the connection pipe P1. Thereby, even if a suck back phenomenon occurs in the reverse osmosis membrane device A, the influence can be blocked so as not to be transmitted to the decarboxylation device B.

  The relief valve V2 is for maintaining the vicinity of the decarbonation film B3, that is, the inside of the decarbonation vessel B1, the inside of the connection pipe P2, and the inside of the connection pipe P3 in a positive pressure state. The relief valve V2 is a valve that opens to the downstream side when the pressure in the pipe line on the upstream side becomes equal to or higher than a certain pressure. In other words, if the pressure in the upstream pipe line does not exceed a certain pressure, it does not open to the downstream side. Therefore, the upstream side (that is, the inside of the connecting pipe P3, the inside of the decarboxylation vessel B1, the inside of the connecting pipe P2) is utilized. ) Can be realized at a certain pressure or higher. Therefore, for example, even if the deaerated water 5 in the downstream connection pipe P4 flows out to the ion exchange resin cylinder C side due to a siphon phenomenon caused by a head difference between the decarbonator B and the ion exchange resin cylinder C. Thus, the upstream side of the relief valve V2 does not become negative pressure.

  An outline of the internal configuration of the ion exchange resin cylinder C is shown in FIG. The ion exchange resin cylinder C is generally configured by filling the cylinder body C1 with the ion exchange resin C2, and is connected to the subsequent stage of the decarbonation apparatus B. The deaerated water 5 that has flowed in from the connection pipe P4 passes through the ion exchange resin C2, and then is taken out as pure water 8 from the intake pipe C3 and is sent to the outside from the connection pipe P5.

  Next, the pure water manufacturing process by this pure water manufacturing apparatus S is demonstrated using the flowchart shown in FIG.

  First, operation of the RO pump E is started, and water supply of the raw water 2 is started (S.1). At the same time, the gas 6 is supplied from the gas supply device D toward the inside of the decarboxylation film B3 (S.2).

  The raw water 2 permeates the reverse osmosis membrane A1 of the reverse osmosis membrane device A to remove salts and the like, and is sent to the decarboxylation device B through the check valve V1 (S.3). The raw water 2 concentrated by the reverse osmosis membrane A1 is drained from the drain pipe A2 (S.4).

  The permeated water 4 sent to the decarboxylation device B flows outside the decarboxylation film B3. Accordingly, the carbon dioxide gas 4a in the permeated water 4 is degassed to the gas 6 side through the decarbonation film B3 (S.5).

  The degassed water 5 from which the carbon dioxide gas has been degassed is sent to the ion exchange resin cylinder C through the relief valve V2 (S.6). By the relief valve V2, the permeated water 4 in the connection pipe P2 and the decarbonator B and the deaerated water 5 in the connection pipe P3 are always in a positive pressure state of a certain pressure or higher even during the production of pure water (S .7). The deaerated water 5 sent to the ion exchange resin cylinder C passes through the ion exchange resin C2 inside the cylinder and becomes pure water 8 and is sent from the connection pipe P5 to the outside (S.8).

  The above process is continued and pure water production is performed. When pure water production is terminated (S.9), the RO pump E is stopped (S.10). Here, when the RO pump E is inverter-controlled by the inverter circuit E1, a rapid pressure drop is prevented, and the pressure of the raw water 2 is gradually reduced.

  Then, when the RO pump E is substantially stopped and the pressure of the raw water 2 on the upstream side of the reverse osmosis membrane A1 drops to substantially atmospheric pressure, the permeate 4 on the downstream side passes through the reverse osmosis membrane A1 due to the action of the osmotic pressure. It tries to flow backward to the upstream side (S.11). However, the check valve V1 provided between the reverse osmosis membrane device A and the decarboxylation device B prevents the reverse flow of the permeate 4 downstream from the check valve V1 upstream from the check valve V1. Therefore (S.12), the permeated water 4 does not flow backward in the vicinity of the decarbonation film B3. Therefore, the permeated water 4 in the vicinity of the decarbonized film B3 does not become negative pressure, and the gas 6 does not enter the permeated water 4 through the decarbonized film B3.

  On the other hand, when the ion exchange resin cylinder C is installed at a position lower than the decarbonator B and there is a difference in the head height between the two, the deaerated water 5 in the connection pipe P4 is caused by the siphon phenomenon even after the RO pump E is stopped. Tries to flow out to the ion exchange resin cylinder C side (S.13). However, the relief valve V2 provided between the decarboxylation device B and the ion exchange resin cylinder C keeps the upstream side of the relief valve V2 in a positive pressure state (S.14). Therefore, the deaerated water 5 in the connection pipe P3 and the permeated water 4 in the vicinity of the decarbonized film B3 do not become negative pressure, and the gas 6 does not enter the permeated water 4 through the decarbonized film B3.

  In the above description, the check valve V1 is used between the decarboxylation device B and the reverse osmosis membrane device A (that is, upstream of the decarboxylation device B), but a relief valve is also used here instead of the check valve. Of course, the backflow prevention function of the relief valve may be used.

[Embodiment 2]
FIG. 5 is a schematic block diagram showing the overall configuration of a pure water production apparatus T using the decarboxylation apparatus F according to Embodiment 2 of the present invention. The pure water production apparatus T is generally configured by connecting a reverse osmosis membrane apparatus A, a decarbonation apparatus F, and an ion exchange resin cylinder C in order from the upstream side, and further includes a control device (valve opening / closing control device) G. is doing. Note that the same reference numerals in the second embodiment denote the same parts as those in the first embodiment, and a description thereof will be omitted.

  The decarboxylation device F includes a decarbonation vessel B1, an on-off valve VC1 (first on-off valve) as a backflow prevention means, and an on-off valve VC2 (second on-off valve) as a positive pressure holding means, and a reverse osmosis membrane. It is connected between the apparatus A and the ion exchange resin cylinder C. The on-off valve VC1 is provided on the upstream side of the decarbonation vessel B1, and the on-off valve VC2 is provided on the downstream side of the decarbonation vessel B1.

  The control device G is for performing on / off control of the on-off valve VC1 and on-off valve VC2, and is connected to both the on-off valves VC1 and VC2. The control device G may be, for example, a computer or a controller capable of storing an operation program such as a sequencer. A pressure sensor 10 for detecting the pressure of the permeated water 4 is provided between the on-off valve VC1 and the decarboxylation vessel B1, and the sensor output is input to the control device G.

  Of the pure water production process by the pure water production apparatus T, the process of stopping the RO pump E and finishing the purification will be described with reference to the flowchart shown in FIG.

  During the production of pure water, the RO pump E operates and both the on-off valves VC1 and VC2 are opened, and the raw water 2, the permeated water 4 and the degassed water 5 are the reverse osmosis membrane device A, decarbonation device F, ion exchange. The pure water 8 passes through the resin cylinder C and is sent to the outside (S.21). At the end of pure water production (S.22), the RO pump E is first gradually stopped (S.23). When the RO pump E can be controlled by the inverter circuit E1, the positive pressure holding control in the vicinity of the decarbonation film B3 can be easily performed. At that time, the pressure state of the permeate 4 is constantly monitored by the pressure sensor 10 and input to the control device G.

  When the pressure of the permeated water 4 becomes the first predetermined pressure (S.24), the control device G first closes the on-off valve VC2 (S.25). When the pressure of the permeated water 4 is lower than the first predetermined pressure and becomes the second predetermined pressure that is positive (S.26), the control device G closes the on-off valve VC1 (S.26). .27).

  Since the on-off valve VC2 is closed before the on-off valve VC1 when the pressure of the permeated water 4 reaches the first predetermined pressure, the permeated water 4 in the vicinity of the deaerated water 5 and the decarbonized film B3 in the connection pipe P3. Is not affected by, for example, siphoning or the like subsequent to the on-off valve VC2. Therefore, the deaerated water 5 in the connection pipe P3 and the permeated water 4 in the vicinity of the decarbonized film B3 do not become negative pressure, and the gas 6 does not enter the permeated water 4 through the decarbonized film B3.

  Further, since the on-off valve VC1 is closed when the pressure of the permeated water 4 reaches the second predetermined pressure, the permeated water 4 in the vicinity of the decarbonation film B3 flows backward, for example, due to osmotic pressure from the on-off valve VC1. Not affected by etc. Therefore, the permeated water 4 in the vicinity of the decarbonized film B3 does not become negative pressure, and the gas 6 does not enter the permeated water 4 through the decarbonized film B3.

  The second predetermined pressure is preferably greater than 0.02 MPa. This is because if the pressure is 0.02 MPa or less, gas may be mixed into the permeated water 4 through the decarbonation film B3.

  When controlling the time (delay time) from the closing of the second on-off valve VC2 to the closing of the first on-off valve VC1, when the piping length between the RO pump E and the decarbonation film B3 is long It is preferable to set the delay time long in consideration of the influence of inertial resistance. On the other hand, when the ion exchange resin cylinder C in the subsequent stage of the decarbonation film B3 is at a low position and strongly causes the siphon phenomenon, it is preferable to set the delay time short.

  Further, depending on the performance inherent to the pump, it is preferable to set a long delay time when the RO pump E requires a few seconds from the stop signal transmission to the impeller stop, such as a pump with an inverter control function. Although it depends on installation conditions, 1 to 3 seconds are preferable.

[Embodiment 3]
FIG. 7 is a schematic block diagram showing an overall configuration of a pure water production apparatus U using a decarboxylation apparatus H according to Embodiment 3 of the present invention. This pure water production device U is generally configured by connecting a reverse osmosis membrane device A, a decarbonation device H, and an ion exchange resin cylinder C in order from the upstream side, and further has a control device (valve opening / closing control device) G. is doing. Note that the same reference numerals in the third embodiment denote the same parts as in the first and second embodiments, and a description thereof will be omitted.

  The decarboxylation apparatus H includes a decarbonation vessel B1, a check valve V1 as a backflow prevention means, an accumulator 12 as a positive pressure holding means, and an on-off valve VC2, and includes a reverse osmosis membrane apparatus A and an ion exchange resin cylinder C. Connected between. The check valve V1 is provided on the upstream side of the decarboxylation vessel B1, and the on-off valve VC2 is provided on the downstream side of the decarboxylation vessel B1. An accumulator 12 is provided between the check valve V1 and the decarbonation vessel B1.

  The control device G is for performing on / off control of the on-off valve VC2, and is connected to the on-off valve VC2. A pressure sensor 10 for detecting the pressure of the permeated water 4 is provided between the check valve V1 and the decarboxylation vessel B1, and the sensor output is input to the control device G.

  As shown in FIG. 8A, the accumulator 12 has a body 12b having a bladder 12b made of an elastic resin such as nitrile rubber, and is connected to the connection pipe P2. . A gas for accumulating pressure is sealed inside the bladder 12b, and a space 12c defined by the outside of the bladder 12b and the inside of the main body case 12a is communicated with the inside of the connection pipe P2, and the permeated water 4 is filled in the space 12c. ing.

  This accumulator 12 is shown in FIG. 8 (b) when the pressure of the permeated water 4 is compressed and the bladder 12b is compressed as shown in FIG. 8 (a). As described above, the bladder 12b is expanded to have a function of reducing the pressure change of the permeate 4. The accumulator 12 is generally used for the purpose of reducing the pulsation of the liquid flowing down in the pipe. In the third embodiment, the accumulator 12 is used for the purpose of maintaining the positive pressure of the permeate 4 near the decarbonation film B3. . In the third embodiment, the accumulator 12 is provided between the check valve V1 and the decarboxylation vessel B1, but may be provided between the decarboxylation vessel B1 and the on-off valve VC2.

  In the pure water production apparatus U, the process of stopping the RO pump E and terminating the production of pure water is the same as the process (S.21) to the process (S.24) in the second embodiment. That is, the RO pump E is in operation during the production of pure water and the on-off valve VC2 is open (S.21), but the RO pump E is gradually stopped at the end of the pure water production process (S.22). When the pressure of the permeated water 4 becomes the first predetermined pressure (set pressure of the accumulator 12) (S.23), the control device G closes the on-off valve VC2 (S.24).

  Since the on-off valve VC2 is closed when the pressure of the permeated water 4 reaches the first predetermined pressure, the deaerated water 5 in the connection pipe P3 and the permeated water 4 in the vicinity of the decarbonized film B3 are downstream of the on-off valve VC2. The part is not affected by, for example, siphon phenomenon. Further, since the check valve V1 is provided on the upstream side of the decarboxylation device H, the permeated water 4 in the vicinity of the decarboxylation film B3 is not affected by, for example, a suck-back phenomenon or the like in a portion preceding the check valve V1. . Furthermore, since the accumulator 12 is provided between the check valve V1 and the decarboxylation vessel B1, the permeated water 4 in the vicinity of the decarboxylation membrane B3 can be always kept in a positive pressure state even after the RO pump E is stopped. . Therefore, the deaerated water 5 in the connection pipe P3 and the permeated water 4 in the vicinity of the decarbonized film B3 do not become negative pressure, and the gas 6 does not enter the permeated water 4 through the decarbonized film B3.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these, A various deformation | transformation and change are possible within the range of the summary.

[Example 1]
Using the pure water production apparatus S described in the first embodiment, an experiment was conducted as to whether or not the gas 6 is mixed in the permeated water 4 through the decarbonation film 106 by changing the set pressure of the relief valve V2 in various ways. It was. In the experiment, after the pure water production process was performed for a predetermined time at a flow rate of 1 m ³ / h of the raw water 2, the RO pump E was stopped and left for a certain period of time, and the amount of gas contained in the ion exchange resin cylinder C was changed to the site of the cylinder main body C1. This was done by visual confirmation from a glass. A flow meter (not shown) was installed between the reverse osmosis membrane device A and the check valve V1. Table 1 shows the equipment and instruments used in the experiment.

The experimental results are shown in Table 2. When the set pressure of the relief valve V2 was 0.02 MPa, mixing of the gas 6 into the permeated water 4 was not observed when the flow rate of the raw water 2 was 1 to 10 m ³ / h. The positive pressure holding force of the relief valve V2 was measured with a pressure gauge (DU3 / 8 × φ75 × 0.6 MPa: manufactured by Toyo Keiki Co., Ltd.).

It is a schematic block diagram which shows the whole structure of the pure water manufacturing apparatus using the decarboxylation apparatus which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the internal structure of the decarboxylation vessel used for the decarboxylation apparatus shown in FIG. It is a schematic block diagram which shows the internal structure of the ion exchange resin cylinder shown in FIG. It is a flowchart explaining the pure water manufacturing process by the pure water manufacturing apparatus shown in FIG. It is a schematic block diagram which shows the whole structure of the pure water manufacturing apparatus using the decarboxylation apparatus which concerns on Embodiment 2 of this invention. It is a flowchart explaining the process which stops a RO pump and complete | finishes a pure water manufacturing process among the pure water manufacturing processes by the pure water manufacturing apparatus shown in FIG. It is a schematic block diagram which shows the whole structure of the pure water manufacturing apparatus using the decarboxylation apparatus which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the internal structure of the accumulator shown in FIG. It is a schematic block diagram which shows the whole structure of the pure water manufacturing apparatus using the conventional decarboxylation apparatus.

Explanation of symbols

2: Raw water 4: Permeated water 4a: Carbon dioxide gas 5: Deaerated water 6: Gas 8: Pure water 10: Pressure sensor 12: Accumulator 12a: Main body case 12b: Bladder 12c: Space 100: Pure water production apparatus 101: Reverse osmosis Membrane device 102: Decarbonation device 103: Ion exchange device 104: RO pump 105: Reverse osmosis membrane 106: Decarbonation membrane 107: Drain pipe 108: Gas supply device S, T, U: Pure water production device A: Reverse osmosis membrane Device A1: Reverse osmosis membrane A2: Drainage pipes B, F, H: Decarbonation device B1: Decarbonation vessel B2: Vessel body B3: Decarbonation membrane C: Ion exchange resin cylinder (ion exchange device)
C1: cylinder main body C2: ion exchange resin C3: intake pipe D: gas supply device E: RO pump E1: inverter circuit G: control device (valve opening / closing control device)
P1 to P7: Connection piping V1: Check valve (backflow prevention means)
V2: Relief valve (positive pressure holding means)
VC1: first on-off valve (backflow prevention means)
VC2: second on-off valve (positive pressure holding means)

Claims (6)

A decarboxylation device connected between a reverse osmosis membrane device and an ion exchange device, for degassing the carbon dioxide gas in the permeated water that has passed through the reverse osmosis membrane device and feeding degassed water toward the ion exchange device. There,
A decarbonation membrane,
A backflow prevention means provided on the upstream side of the decarboxylation film, for preventing backflow of the permeate;
And a positive pressure holding means that is provided downstream of the backflow prevention means and holds the degassed water in a positive pressure state.   The decarboxylation apparatus according to claim 1, wherein the backflow prevention means is a check valve, and the positive pressure holding means is an accumulator.   The decarboxylation apparatus according to claim 1, wherein the backflow prevention means is a check valve, and the positive pressure holding means is a relief valve provided on the downstream side of the decarbonation film. The backflow prevention means is a first on-off valve capable of opening / closing control, and the positive pressure holding means is a second on-off valve provided on the downstream side of the decarbonation film and capable of opening / closing control, and
When stopping the feed of raw water, the first on-off valve is closed before the first on-off valve is closed, and the first permeated water pressure becomes 0.02 MPa or less before the first on-off valve is closed. The decarboxylation device according to claim 1, further comprising a valve opening / closing control device for closing the opening / closing valve. A decarbonation method for degassing carbon dioxide gas in permeated water that has permeated through the reverse osmosis membrane device by a decarboxylation device connected between a reverse osmosis membrane device and an ion exchange device and having a decarbonation membrane,
A step of preventing reverse flow of the permeated water by a reverse flow preventing means provided upstream of the decarbonation membrane when stopping the supply of raw water to the reverse osmosis membrane device;
And a step of holding the degassed water in a positive pressure state by a positive pressure holding means provided on the downstream side of the backflow preventing means. A decarbonation method for degassing carbon dioxide gas in permeated water that has permeated through the reverse osmosis membrane device by a decarboxylation device connected between a reverse osmosis membrane device and an ion exchange device and having a decarbonation membrane,
When stopping the supply of raw water to the reverse osmosis membrane device, the first on-off valve provided on the upstream side of the decarbonation membrane is closed before the first on-off valve provided on the downstream side of the decarbonation membrane. Closing the two on-off valves;
And a step of closing the first on-off valve before the pressure of the permeated water becomes 0.02 MPa or less.

Images