JP5853621B2 - Water treatment system - Google Patents

Description

  The present invention relates to a water treatment system for producing pure water by purifying (desalting) permeated water produced by a membrane separation device using an electric ion exchange device.

  In semiconductor manufacturing processes, electronic component cleaning, medical instrument cleaning, and the like, high-purity pure water that does not contain impurities is used. In the case of producing this kind of pure water, in general, supply water such as ground water or tap water is subjected to membrane separation treatment in a membrane separation apparatus using a reverse osmosis membrane (hereinafter also referred to as “RO membrane module”). To produce permeated water from which most of the dissolved salts have been removed. Then, the purity is further increased by purifying the permeated water with an electric ion exchange device (electrodeionization device; hereinafter also referred to as “EDI device”).

  The EDI apparatus includes a desalination chamber and a concentration chamber partitioned by a cation exchange membrane and an anion exchange membrane. The desalting chamber is filled with an ion exchanger (resin or fiber). When permeated water is supplied to the desalting chamber and the concentrating chamber, residual salts (ions) contained in the permeated water are captured by the ion exchanger in the desalting chamber, and the permeated water becomes purified treated water (desalted water). . Further, residual salts captured by the ion exchanger in the desalting chamber move to the concentrating chamber by electric energy. And it is discharged | emitted as concentrated water from a concentration chamber. Thus, in the EDI apparatus, the ions trapped by the ion exchanger move to the concentration chamber, so that the regeneration state can always be maintained.

  However, the permeated water supplied to the EDI apparatus includes polyvalent ions having high selectivity with respect to the ion exchanger, and weak electrolytes (hereinafter referred to as “ions”) such as silica and carbonic acid which are difficult to elute electrically. ) Is included. These ions gradually accumulate in the ion exchanger. When ions accumulated in the ion exchanger are eluted into the treated water, the quality of the treated water is deteriorated. Therefore, in the EDI apparatus, the refining process is stopped every several months, and a regeneration operation for electrically eluting ions accumulated in the ion exchanger is performed (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 11-57420 JP 2010-99594 A

  In the conventional water treatment system, the purification process of the permeated water is temporarily interrupted during the regeneration operation of the EDI apparatus. During this time, pure water cannot be supplied to the demand point, so that the operating efficiency and productivity of the demand point are lowered. For this reason, the water treatment system which can supply a pure water to a demand location continuously and stably was desired.

  Accordingly, an object of the present invention is to provide a water treatment system that can supply pure water continuously and stably to a demand point even during regeneration operation of an electric ion exchange device with a simple system configuration. To do.

The present invention relates to a membrane separation device that performs membrane separation treatment of feed water into permeated water and concentrated water, an electric ion exchange device that desalinates permeated water to produce first treated water, and permeated water or first water. A mixed bed type ion exchange device for producing a second treated water by desalting the treated water, a silica concentration detecting means for detecting the silica concentration of the permeated water produced by the membrane separator , i) a first flow path for distributing the first treated water produced by the electric ion exchange device to the mixed-bed ion exchange device, and (ii) the electric ion. A flow path portion that can be switched to the second flow path to be circulated to the mixed bed ion exchange apparatus without being circulated to the exchange apparatus; and during the normal operation of the electric ion exchange apparatus, the flow path section is the first flow path. Switch to one channel and regenerate the electric ion exchanger Among comprises a control unit for switching the channel section into the second flow path, wherein, during normal operation of the electric ion exchange apparatus, detecting the silica concentration of the silica concentration detecting means in advance If it is more than the set reference | standard silica density | concentration, it is related with the water treatment system which switches the said flow-path part to a said 2nd flow path .

The present invention also provides a membrane separation device that performs membrane separation treatment of feed water into permeated water and concentrated water, an electric ion exchange device that produces desalted salt from the permeated water, and permeated water. Mixed bed type ion exchange apparatus for producing second treated water by desalting, silica concentration detecting means for detecting the silica concentration of the permeated water produced by the membrane separator , and (i) the permeated water, A third flow path for distribution to the electric ion exchange apparatus without distribution to the mixed bed type ion exchange apparatus; and (ii) distribution to the mixed bed type ion exchange apparatus without distribution to the electric ion exchange apparatus. A flow channel portion that can be switched to the fourth flow channel, and during the normal operation of the electric ion exchange device, the flow channel portion is switched to the third flow channel and during the regeneration operation of the electric ion exchange device. , and a control unit for switching the channel section into the fourth channel If the detected silica concentration of the silica concentration detecting means is equal to or higher than a preset reference silica concentration during normal operation of the electric ion exchange device, the control unit moves the flow channel portion into the fourth flow channel. The present invention relates to a water treatment system to be switched .

  A flow rate detecting means for detecting a flow rate of the permeated water produced by the membrane separation device and outputting a detected flow rate value corresponding to the flow rate; a supply water line for supplying supply water to the membrane separation device; and an input A pressure pump that is driven at a rotational speed according to the driving frequency and pumps the feed water flowing through the feed water line toward the membrane separation device, and a drive frequency corresponding to the input current value signal. An inverter that outputs to the pressurizing pump, and the control unit is configured so that the detected flow rate value output from the flow rate detecting means is a preset target flow rate value at least during normal operation of the electric ion exchange device. The driving frequency of the pressurizing pump is calculated by the speed type digital PID algorithm so that the current value signal corresponding to the calculated value of the driving frequency is output to the inverter. Door is preferable.

  A drain valve capable of adjusting a discharge flow rate of the concentrated water discharged from the membrane separation device, and the control unit is configured such that the drain flow rate of the concentrated water flows during the regeneration operation of the electric ion exchange device. It is preferable to control the drain valve so as to be larger than the discharge flow rate set during normal operation of the ion exchange apparatus.

  The control unit includes a storage tank that stores the first treated water and / or the second treated water, and a water level detection unit that detects a water level of the storage tank, and the control unit has a detection water level detected in advance by the water level detection unit. If it is equal to or higher than the set reference storage water level, the target flow rate value of the permeate during the regeneration operation of the electric ion exchange device is lower than the target flow rate value of the permeate during the normal operation of the electric ion exchange device. It is preferable to set.

  ADVANTAGE OF THE INVENTION According to this invention, the water treatment system which can supply a pure water to a demand location continuously and stably also in the regeneration operation of an electric ion exchange apparatus with a simple system configuration can be provided.

1 is an overall configuration diagram of a water treatment system 1 according to a first embodiment. (A) is explanatory drawing which shows the 1st flow path of the water treatment system 1. FIG. (B) is explanatory drawing which shows the 1st flow path and the 2nd flow path of the water treatment system 1. FIG. 4 is a flowchart showing a processing procedure when a flow path unit is switched in the control unit 10. 5 is a flowchart showing a processing procedure when a RO membrane module recovery rate is set in the control unit 10; It is a flowchart which shows the process sequence in the case of performing flow volume feedback water volume control in the control part 10. FIG. 5 is a flowchart showing a processing procedure when the RO membrane module recovery rate control is executed in the control unit 10. It is a whole block diagram of the water treatment system 1A which concerns on 2nd Embodiment. It is a flowchart which shows the process sequence in the case of setting the target flow rate value and collection | recovery rate of the permeated water W2 in the control part 10. FIG. It is a whole block diagram of the water treatment system 1B which concerns on 3rd Embodiment. (A) is explanatory drawing which shows the 1st flow path of the water treatment system 1B. (B) is explanatory drawing which shows the 2nd flow path of the water treatment system 1B.

(First embodiment)
A water treatment system 1 according to a first embodiment of the present invention will be described with reference to the drawings. The water treatment system 1 according to the first embodiment is applied to, for example, a pure water production system that produces pure water from fresh water.

  FIG. 1 is an overall configuration diagram of a water treatment system 1 according to the first embodiment. 2A and 2B are explanatory views showing the first flow path and the second flow path of the water treatment system 1. FIG. 3 is a flowchart showing a processing procedure when the flow path unit is switched in the control unit 10. FIG. 4 is a flowchart showing a processing procedure when the RO membrane module recovery rate is set in the control unit 10. FIG. 5 is a flowchart showing a processing procedure when the control unit 10 executes flow rate feedback water volume control. FIG. 6 is a flowchart showing a processing procedure when the recovery rate control of the RO membrane module is executed in the control unit 10.

  As shown in FIG. 1, the water treatment system 1 according to the first embodiment includes a pressurizing pump 2, an inverter 3, an RO membrane module 4 as a membrane separation device, and an EDI device (electric ion exchange device) 5. And a cartridge polisher device (hereinafter also referred to as “CP device”) 6 as a mixed bed type ion exchange device. Further, the water treatment system 1 includes a flow rate sensor 7 as a flow rate detection unit, a silica concentration sensor 8 as a silica concentration detection unit, a carbonic acid concentration sensor 9 as a carbonic acid concentration detection unit, a control unit 10, and a first waste water. A valve 11, a second drain valve 12, a third drain valve 13, a first switching valve 14, and a second switching valve 15 are provided.

  Further, the water treatment system 1 includes a first water line L1, a second water line L2, a third water line L3, a fourth water line L4, and a fifth water line as supply water lines. L5, a first concentrated water line L6, a second concentrated water line L7, and a drain line for the first concentrated water W3 (first drain line L11, second drain line L12 and third drain line L13). .

  The first switching valve 14, the second switching valve 15, and the second water flow line L <b> 2 to the fifth water flow line L <b> 5 described above constitute a flow path portion in the present embodiment (hereinafter collectively referred to as “flow”). Also referred to as "road.") The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a path, and a pipeline.

  The first water flow line L <b> 1 is a line that supplies the supply water W <b> 1 to the RO membrane module 4. The upstream end of the first water flow line L1 is connected to a supply source (not shown) of the supply water W1. The downstream end of the first water passage line L <b> 1 is connected to the primary inlet port of the RO membrane module 4.

  The pressurizing pump 2 is a device that sucks in the supply water W1 flowing through the first water passage line L1 and discharges it toward the RO membrane module 4. The pressurizing pump 2 is provided on the upstream side of the RO membrane module 4 in the first water passage line L1. The pressurizing pump 2 is electrically connected to an inverter 3 (described later). The driving power whose frequency is converted is supplied from the inverter 3 to the pressurizing pump 2. The pressurizing pump 2 is driven at a rotational speed corresponding to the frequency of the supplied driving power (hereinafter also referred to as “driving frequency”).

  The inverter 3 is an electric circuit that supplies driving power whose frequency is converted to the pressurizing pump 2. The inverter 3 is electrically connected to the control unit 10. The inverter 3 receives a current value signal from the control unit 10. The inverter 3 outputs driving power having a driving frequency corresponding to the input current value signal to the pressurizing pump 2.

  The RO membrane module 4 is a facility for subjecting the supply water W1 sent from the pressurization pump 2 to membrane separation treatment into permeated water W2 from which dissolved salts have been removed and first concentrated water W3 from which dissolved salts have been concentrated. . The RO membrane module 4 includes a single or a plurality of reverse osmosis membrane elements (not shown). The RO membrane module 4 performs membrane separation treatment of the supply water W1 with these reverse osmosis membrane elements to produce permeated water W2 and first concentrated water W3.

  Further, an upstream end of the first concentrated water line L6 is connected to the primary outlet port of the RO membrane module 4. The first concentrated water line L6 is a line for sending the first concentrated water W3 out of the RO membrane module 4. The downstream side of the first concentrated water line L6 branches to the first drainage line L11, the second drainage line L12, and the third drainage line L13 at the branch portions J7 and J8.

  A first drain valve 11 is provided in the first drain line L11. A second drain valve 12 is provided in the second drain line L12. A third drain valve 13 is provided in the third drain line L13.

  The first drain valve 11 to the third drain valve 13 are valves that adjust the drainage flow rate of the first concentrated water W3 sent from the first concentrated water line L6. The first drain valve 11 can open and close the first drain line L11. The second drain valve 12 can open and close the second drain line L12. The third drain valve 13 can open and close the third drain line L13.

  Each of the first drain valve 11 to the third drain valve 13 includes a constant flow valve mechanism (not shown). The constant flow valve mechanisms are set to different flow values in the first drain valve 11 to the third drain valve 13. For example, the drainage flow rate of the first drain valve 11 is set so that the recovery rate of the RO membrane module 4 is 80% in the open state. The drainage flow rate of the second drain valve 12 is set so that the recovery rate of the RO membrane module 4 is 75% in the open state. The drainage flow rate of the third drain valve 13 is set so that the recovery rate of the RO membrane module 4 is 70% in the open state.

The recovery rate and the ratio of the flow rate _{Q 2} of the permeate water W2 to the flow rate to _{Q 1} supply water W1 is supplied to the RO membrane module 4 _{(i.e., Q 2 / Q 1 × 100} ) refers to. Therefore, when the recovery rate is lowered during the regeneration operation of the EDI device 5 than during the normal operation, the drainage flow rate of the first concentrated water W3 discharged from the RO membrane module 4 is larger than the discharge flow rate during the normal operation. Become.

  The drainage flow rate of the first concentrated water W3 discharged from the first concentrated water line L6 can be adjusted in stages by selectively opening and closing the first drainage valve 11 to the third drainage valve 13. For example, only the second drain valve 12 is opened, and the first drain valve 11 and the third drain valve 13 are closed. In this case, the recovery rate of the RO membrane module 4 can be 75%. Further, the first drain valve 11 and the second drain valve 12 are opened, and only the third drain valve 13 is closed. In this case, the recovery rate of the RO membrane module 4 can be set to 70%. Therefore, in the present embodiment, the drainage flow rate of the first concentrated water W3 is such that the recovery rate of the RO membrane module 4 is 50% to 80% by selectively opening and closing the first drainage valve 11 to the third drainage valve 13. Can be adjusted in steps of every 5%.

  In the present embodiment, the recovery rate of the RO membrane module 4 is set to 80% during normal operation and 60% during regeneration operation. That is, the control unit 10 sets the recovery rate to 80% during normal operation of the EDI apparatus 5 and sets the actual drainage flow rate of the first concentrated water W3 discharged from the RO membrane module 4 in advance. The opening and closing of the first drain valve 11 to the third drain valve 13 are controlled so that the drain flow rate is the same as the drain flow rate.

  In addition, during the regeneration operation of the EDI device 5, the control unit 10 sets the recovery rate lower than that during the normal operation to 60%, and the actual drainage flow rate of the first concentrated water W3 discharged from the RO membrane module 4 Is controlled to open and close the first drain valve 11 to the third drain valve 13 so that the drain flow rate is higher than a preset target drain flow rate.

  The recovery rate of the RO membrane module 4 may be set to a recovery rate during normal operation and a recovery rate during regeneration operation lower than that. As described above, in the configuration of the present embodiment, the drainage flow rate of the first concentrated water W3 can be adjusted stepwise. For this reason, the recovery rate during normal operation and the recovery rate during regeneration operation can be appropriately selected between 50% and 80%.

  The first drain valve 11 to the third drain valve 13 are each electrically connected to the control unit 10. The opening and closing of the valve body in the first drain valve 11 to the third drain valve 13 is controlled by a drive signal from the control unit 10.

  The second water passage line L <b> 2 is a line that supplies the permeated water W <b> 2 manufactured by the RO membrane module 4 to the EDI device 5. The upstream end of the second water passage line L <b> 2 is connected to the secondary port of the RO membrane module 4. Further, the downstream end of the second water flow line L2 is connected to a primary port (an inlet side of a desalination chamber 5a and a concentration chamber 5b described later) of the EDI device 5.

  The EDI apparatus 5 is an apparatus for producing a first treated water W4 as pure water by subjecting the permeated water W2 produced by the RO membrane module 4 to desalination. The EDI apparatus 5 includes a plurality of desalting chambers and a plurality of concentrating chambers partitioned by a cation exchange membrane and an anion exchange membrane (in FIG. 1, the diagram is simplified and shown as a desalting chamber 5 a and a concentrating chamber 5 b. ). The permeated water W2 flowing through the second water passage line L2 is branched at the branch portion J5 and supplied to the desalting chamber 5a and the concentration chamber 5b, respectively. Residual salts contained in the permeated water W2 are captured by an ion exchanger (not shown) filled in the desalting chamber 5a and become first treated water (desalted water) W4. Further, residual salts captured by the ion exchanger in the desalting chamber 5a move to the concentrating chamber 5b by electric energy. And the water containing residual salts is discharged | emitted as the 2nd concentrated water W5 through the 2nd concentrated water line L7 from the concentration chamber 5b.

  During normal operation, the EDI apparatus 5 desalinates the permeated water W2 produced by the RO membrane module 4 to produce first treated water W4 as pure water. During the normal operation of the EDI apparatus 5, the flow path portion is switched to the first flow path (described later). In the first flow path, the permeated water W2 produced by the RO membrane module 4 flows to the EDI device 5 via the second water passage line L2, and the first treated water W4 produced by the EDI device 5 is the third. It distribute | circulates to CP apparatus 6 through the water flow line L3.

  On the other hand, during the regeneration operation, the EDI device 5 performs a process of electrically eluting ions accumulated in the ion exchanger by increasing the applied voltage as compared with the normal operation. During the regeneration operation of the EDI device 5, the desalination treatment of the permeated water W <b> 2 is not performed in the EDI device 5. For this reason, during the regeneration operation of the EDI apparatus 5, the flow path portion is switched to the second flow path (described later). In the second flow path, the permeated water W2 produced by the RO membrane module 4 flows to the CP device 6 (described later) without flowing to the EDI device 5. That is, during the regeneration operation of the EDI device 5, desalting is performed by the CP device 6 instead of the EDI device 5.

  The 3rd water flow line L3 is a line which distribute | circulates the 1st treated water W4 manufactured with the EDI apparatus 5 to CP apparatus 6. FIG. The upstream end of the third water flow line L3 is connected to the secondary port of the EDI device 5 (the outlet side of the desalination chamber 5a). Further, the downstream end portion of the third water flow line L <b> 3 is connected to the primary side port of the CP device 6.

  The 1st switching valve 14 is provided in the 3rd water flow line L3. The first switching valve 14 can open and close a line on the upstream side (EDI device 5 side) of the connection portion J6 in the third water flow line L3. The first switching valve 14 supplies the first treated water W4 manufactured by the EDI device 5 to the first flow path for circulating the first treated water W4 to the CP device 6 or the permeated water W2 manufactured by the RO membrane module 4 This is one of the valves that can be switched to the second flow path that circulates to the CP device 6 via the line L5. The first switching valve 14 is configured by, for example, an electric or electromagnetic two-way valve. The first switching valve 14 is electrically connected to the control unit 10. The opening / closing of the valve in the first switching valve 14 is controlled by a valve opening / closing signal transmitted from the control unit 10.

  The fifth water passage line L5 is configured to pass the permeated water W2 flowing through the second water passage line L2 to the third water passage line L3 when the flow passage portion is switched to the second flow passage (described later) by the control unit 10. 2 is a bypass line that joins downstream of the first switching valve 14. The upstream end of the fifth water line L5 is connected to the second water line L2 at the connection J4. The connection part J4 is disposed between the connection part J3 and the branch part J5. Further, the downstream end of the fifth water passage line L5 is connected to the third water passage line L3 at the connection portion J6. The connection part J6 is arrange | positioned between the 1st switching valve 14 and CP apparatus 6 (after-mentioned).

  The 2nd switching valve 15 is provided in the 5th water flow line L5. The 2nd switching valve 15 can open and close the 5th water flow line L5. The second switching valve 15 distributes the permeated water W2 manufactured by the RO membrane module 4 to the EDI device 5 or the first flow path for distributing the permeated water W2 manufactured by the RO membrane module 4 to the EDI device 5. This is one of the valves that can be switched to the second flow path that circulates to the CP device 6 without making it. The second switching valve 15 is configured by, for example, an electric or electromagnetic two-way valve. The second switching valve 15 is electrically connected to the control unit 10. The opening and closing of the second switching valve 15 is controlled by a valve opening / closing signal transmitted from the control unit 10.

  The CP device 6 is a device that desalinates the first treated water W4 produced by the EDI device or the permeated water W2 produced by the RO membrane module 4 to produce the second treated water W6. During the normal operation of the EDI device 5, the CP device 6 further desalinates the first treated water W4 produced by the EDI device 5 to produce the second treated water W6. Further, during the regeneration operation of the EDI device 5, the permeated water W2 produced by the RO membrane module 4 is desalted to produce the second treated water W6.

  The CP device 6 is a mixed bed type ion exchange device including a non-regenerative type cartridge tower filled with a cation resin and an anion resin. The CP device 6 is connected to the downstream side of the EDI device 5 through the fourth water passage line L4. A fourth water passage line L <b> 4 is connected to the secondary side port of the CP device 6. The 4th water flow line L4 is a line which sends out the 2nd treated water W6 manufactured with CP device 6 to a demand point on the downstream side. In the CP apparatus 6, when the ion removal capacity of the cartridge tower is saturated, the cartridge tower is replaced with a cartridge tower filled with regenerated cationic resin and anion resin.

  The flow rate sensor 7 is a device that detects the flow rate of the permeated water W2 flowing through the second water passage line L2. The flow sensor 7 is connected to the second water flow line L2 at the connection portion J1. The connection portion J1 is disposed between the RO membrane module 4 and the connection portion J2. The flow sensor 7 is electrically connected to the control unit 10. The flow rate per unit time of the permeated water W2 detected by the flow rate sensor 7 (hereinafter also referred to as “detected flow rate value”) is transmitted to the control unit 10 as a detection signal.

  The silica concentration sensor 8 is a device that detects the silica concentration of the permeated water W2 flowing through the second water passage line L2. Silica is a kind of weak electrolyte that can be contained in the permeated water W2. The silica concentration sensor 8 is connected to the second water passage line L2 at the connection portion J2. The connection part J2 is arrange | positioned between the connection part J1 and the connection part J3. The silica concentration sensor 8 is electrically connected to the control unit 10. The silica concentration of the permeated water W2 detected by the silica concentration sensor 8 (hereinafter also referred to as “detected silica concentration value”) is transmitted to the control unit 10 as a detection signal.

  The carbonic acid concentration sensor 9 is a device that detects the carbonic acid concentration (dissolved carbonic acid concentration) of the permeated water W2 flowing through the second water passage line L2. Carbonic acid is a kind of weak electrolyte that can be contained in the permeated water W2. The carbonic acid concentration sensor 9 is connected to the second water passage line L2 at the connection portion J3. The connection part J3 is arrange | positioned between the connection part J2 and the connection part J4. The carbonic acid concentration sensor 9 is electrically connected to the control unit 10. The carbonate concentration of the permeated water W2 detected by the carbonate concentration sensor 9 (hereinafter also referred to as “detected carbonate concentration value”) is transmitted to the control unit 10 as a detection signal.

  The control unit 10 is configured by a microprocessor (not shown) including a CPU and a memory. The microprocessor incorporates an integrated timer unit (hereinafter also referred to as “ITU”) that manages time measurement and the like.

  As the flow rate feedback water amount control, the control unit 10 controls the pressurizing pump 2 by the speed type digital PID algorithm using the physical quantity in the system so that the detected flow rate value of the flow rate sensor 7 becomes a preset target flow rate. A drive frequency for driving is calculated, and a current value signal corresponding to the calculated value of the drive frequency is output to the inverter 3. The flow rate feedback water amount control will be described later.

  When the time measured by the ITU reaches a preset regeneration standby period (for example, two months) during normal operation of the EDI device 5, the control unit 10 uses the flow path to regenerate the EDI device 5. The part is switched from the first flow path to the second flow path. In this case, the control unit 10 notifies the system administrator of a message or the like indicating that the EDI device 5 is to be regenerated through a user interface (not shown). In addition, when the regeneration operation of the EDI device 5 is completed, the control unit 10 switches the flow channel unit from the second flow channel to the first flow channel in order to normally operate the EDI device 5.

  The first channel is a channel when the EDI device 5 is normally operated. When the control unit 10 switches the flow channel unit to the first flow channel, the permeated water W2 produced by the RO membrane module 4 flows to the desalination chamber 5a of the EDI device 5 via the second water flow line L2. The second flow path is a flow path when the EDI device 5 is regenerated. When the control unit 10 switches the flow channel unit to the second flow channel, the permeated water W2 produced by the RO membrane module 4 passes through the fifth water flow line L5 without flowing through the desalination chamber 5a of the EDI device 5. To the CP device 6. The first channel and the second channel will be described in detail later.

In addition, the control unit 10 detects the flow rate when the detected silica concentration value of the silica concentration sensor 8 is equal to or higher than a preset reference silica concentration value (for example, 0.5 mgSiO ₂ / L) during normal operation of the EDI apparatus 5. The path portion is switched from the first flow path to the second flow path. As described above, even when the time measured by the ITU has not reached the preset regeneration standby period, the control unit 10 sets the flow path unit as long as the detected silica concentration value of the permeated water W2 is equal to or higher than the reference silica concentration value. Switch from the first channel to the second channel.

Further, the control unit 10 is configured such that, during normal operation of the EDI apparatus 5, if the detected carbonic acid concentration value of the carbonic acid concentration sensor 9 is equal to or higher than a preset reference carbonic acid concentration value (for example, 1 mg CO ₂ / L), Is switched from the first flow path to the second flow path. Thus, even when the time measured by the ITU has not reached the preset regeneration standby period, the control unit 10 sets the flow path unit as long as the detected carbonate concentration value of the permeated water W2 is equal to or greater than the reference carbonate concentration value. Switch from the first channel to the second channel.

Further, the control unit 10 sets the drainage flow rate of the first concentrated water W3 during the normal operation of the EDI device 5 during the regeneration operation of the EDI device 5 as the drainage flow rate control of the first concentrated water W3 in the RO membrane module 4. The recovery rate of the RO membrane module 4 is set so as to be larger than the discharged flow rate, and the first drain valve 11 to the third drain valve 13 are controlled. Based on the set target flow rate value Q _p ′ and the recovery rate R (described later), the control unit 10 calculates the drainage flow rate Q _c of the first concentrated water W3 by the following equation (1).
_{Q c = Q p '/ R} -Q p' (1)
The recovery rate control of the RO membrane module 4 will be described later.

  Next, the first flow path and the second flow path in the water treatment system 1 will be described with reference to FIG. In FIG. 2, the RO membrane module 4, the EDI device 5, the CP device 6, the first water passage line L1 to the fifth water passage line L5, the second concentrated water line L7, the first switching valve 14, and the second switching valve. 15, only the connection parts J4 and J6 are shown. Moreover, in FIG. 2, the line through which the supply water W1 etc. distribute | circulate is shown as a continuous line, and the line which does not distribute | circulate is shown with a broken line. Moreover, in the 1st switching valve 14 and the 2nd switching valve 15, a valve opening is shown in white and a valve closing is shown in black.

  FIG. 2A is an explanatory diagram showing a first flow path of the water treatment system 1. The first channel is a channel when the EDI device 5 is normally operated. When the EDI device 5 is normally operated, the control unit 10 (not shown) opens the first switching valve 14 and closes the second switching valve 15 as shown in FIG. Thereby, the permeated water W2 manufactured by the RO membrane module 4 flows to the EDI device 5 through the second water passage line L2. And the 1st treated water W4 manufactured with the EDI apparatus 5 distribute | circulates to the CP apparatus 6 via the 3rd water flow line L3. Furthermore, the 2nd treated water W6 manufactured with CP apparatus 6 is sent to a demand point via the 4th water flow line L4.

  FIG. 2B is an explanatory diagram showing a second flow path of the water treatment system 1. The second channel is a channel when the EDI device 5 is regenerated. When the regenerating operation of the EDI device 5 is performed, the control unit 10 (not shown) closes the first switching valve 14 and opens the second switching valve 15 as shown in FIG. Thereby, the permeated water W2 manufactured by the RO membrane module 4 flows from the second water passage line L2 to the fifth water passage line L5 at the connection portion J4. The permeated water W2 that has circulated through the fifth water passage line L5 joins the third water passage line L3 at the connection portion J6. Thus, in the second flow path, the permeated water W2 produced by the RO membrane module 4 does not flow to the EDI device 5 (demineralization chamber 5a), but passes through the fifth water flow line L5 and the CP device 6. Circulate to And the 2nd treated water W6 manufactured with CP device 6 is sent to a demand point via the 4th water flow line L4.

  In the water treatment system 1 according to the present embodiment, the channel portion is switched to the first channel during the normal operation of the EDI device 5. In the first flow path, the permeated water W <b> 2 manufactured by the RO membrane module 4 flows to the EDI device 5. Thereby, the permeated water W2 is desalted by the EDI device 5 to produce the first treated water W4. The first treated water W4 is further desalted in the CP device 6 to produce the second treated water W6.

  On the other hand, during the regeneration operation of the EDI apparatus 5, the flow path portion is switched to the second flow path. In the second flow path, the permeated water W2 produced by the RO membrane module 4 flows to the CP device 6 without flowing to the EDI device 5 (desalting chamber 5a). Thereby, the permeated water W2 is desalted by the CP device 6 to produce the second treated water W6. Thus, in the water treatment system 1 according to the present embodiment, the desalination treatment is performed by the CP device 6 even during the regeneration operation of the EDI device 5. Therefore, according to the water treatment system 1 according to the present embodiment, pure water (second treated water W6) can be continuously supplied to the demand point even during the regeneration operation of the EDI device 5.

  Next, the operation in the case of switching the flow path section in the control section 10 will be described with reference to the flowchart shown in FIG. Note that the processing of the flowchart shown in FIG. 3 is repeatedly executed during operation of the water treatment system 1.

In step ST101 shown in FIG. 3, the control unit 10 determines whether the time count _{t 1} by ITU has reached the reproduction waiting period Delta] t _1. In this step ST 101, the control unit 10, time count _{t 1} according to the ITU if it is determined to have reached the playback standby period Δt ₁ (YES), the process proceeds to step ST 102. Further, in step ST 101, the control unit 10, time count _{t 1} by ITU is when it is determined does not reach the reproduction waiting period Delta] t ₁ and (NO), the process proceeds to step ST 106.

In step ST102 (step ST101: YES determination), the control unit 10 controls the first switching valve 14 and the second switching valve 15 so as to switch the flow channel unit to the second flow channel (see FIG. 2B). . When the time t ₁ measured by the ITU reaches the regeneration standby period Δt ₁ , the control unit 10 switches the flow channel unit to the second flow channel and supplies the permeated water W 2 to perform the regeneration operation of the EDI device 5. Distribute to the CP device 6. If the flow path has already been switched to the second flow path, the process proceeds to step ST104 without switching the flow path.

  In step ST103, the control unit 10 executes the regeneration operation of the EDI device 5. In the regeneration operation of the present embodiment, the flow of the permeate W2 to the desalting chamber 5a is stopped and a part of the permeate W2 is allowed to flow to the concentration chamber 5b. Then, by energizing with an applied voltage higher than that during normal operation, ions accumulated in the ion exchanger are electrically eluted and discharged out of the system from the concentration chamber 5b side. When the regeneration operation of the EDI device 5 ends, the process proceeds to step ST104.

  In step ST104, the control part 10 controls the 1st switching valve 14 and the 2nd switching valve 15 so that a flow path part may be switched to a 1st flow path (refer FIG. 2 (A)). When the regeneration operation of the EDI device 5 is completed, the control unit 10 switches the flow channel unit to the first flow channel in order to perform the normal operation of the EDI device 5.

In step ST105, the control unit 10 starts a time count _{t 1} by ITU. Thereby, the process of this flowchart is complete | finished (it returns to step ST101).

On the other hand, the step ST 106: In (step ST 101 NO judgment), the control unit 10 acquires a detection silica concentration value _{S d} permeate W2 detected by silica concentration sensor 8.

In step ST 107, the control unit 10 determines whether or not the detected silica density value S _d is the reference silica concentration value S _s or more set in advance. In step ST107, when the control unit 10 determines that the detected silica concentration value S _d ≧ reference silica concentration value S _s (YES), the process proceeds to step ST108. In step ST105, when the control unit 10 determines that the detected silica concentration value S _d <the reference silica concentration value S _s (NO), the process proceeds to step ST109.

In step ST108 (step ST107: YES determination), the control unit 10 controls the first switching valve 14 and the second switching valve 15 so as to switch the flow channel unit to the second flow channel (see FIG. 2B). . When the detected silica concentration value S _d of the permeated water W2 is equal to or higher than the reference silica concentration value S _s , the control unit 10 suppresses the accumulation of silica in the ion exchanger of the EDI device 5, The part is switched to the second flow path, and the permeated water W <b> 2 is circulated to the CP device 6.

Further, step ST 109: In (step ST 107 NO judgment), the control unit 10 acquires the detection carbonate concentration value _{C d} detected by the carbon dioxide concentration sensor 9.

In step ST110, the control unit 10 determines whether or not the detected carbon dioxide concentration value C _d is a preset reference carbon concentration values C _s or more. In step ST110, when the control unit 10 determines that the detected carbonic acid concentration value C _d ≧ reference carbonic acid concentration value C _s (YES), the process proceeds to step ST108. Thus, when the detection carbonate concentration value C _d is equal to or larger than the reference carbon concentration value C _s is also to prevent the carbon dioxide accumulates in the ion exchanger of EDI device 5, the flow path portion to the second passage The permeated water W2 is circulated to the CP device 6 by switching.

In step ST110, when the control unit 10 determines that the detected carbonic acid concentration value C _d <the reference carbonic acid concentration value C _s (NO), the processing of this flowchart ends (returns to step ST101). .

  Next, the operation when the recovery rate of the RO membrane module 4 is set in the control unit 10 will be described with reference to the flowchart shown in FIG. Note that the process of the flowchart shown in FIG. 4 is repeatedly executed during operation of the water treatment system 1.

  In step ST201 shown in FIG. 4, the control unit 10 determines whether or not the water treatment system 1 is in normal operation. In step ST201, when the control unit 10 determines that the normal operation is being performed (YES), the process proceeds to step ST202. In Step ST201, when the control unit 10 determines that the normal operation is not performed (NO), that is, the regeneration operation is performed, the process proceeds to Step ST203.

  In step ST202 (step ST201: YES determination), the control unit 10 sets the recovery rate of the RO membrane module 4 to 80%. Thereby, the process of this flowchart is complete | finished (it returns to step ST201). As described above, the control unit 10 sets the recovery rate of the RO membrane module 4 to the normal recovery rate (80%) during normal operation.

  On the other hand, in step ST203 (step ST201: NO determination), the control unit 10 sets the recovery rate of the RO membrane module 4 to 60%. Thereby, the process of this flowchart is complete | finished (it returns to step ST201).

  Thus, the control unit 10 sets the recovery rate of the RO membrane module 4 to a recovery rate (60%) lower than usual when the regeneration operation is being performed. Thereby, during the regeneration operation, the amount of the first concentrated water W3 discharged from the RO membrane module 4 becomes larger than the discharge flow rate set during the normal operation. During the regeneration operation, by reducing the recovery rate of the RO membrane module 4, the amount of ions such as silica and carbonic acid leaking into the permeate W2 can be reduced, and the purity of the permeate W2 can be increased. Thereby, highly purified pure water can be manufactured, suppressing the fall of the removal capability of CP apparatus 6. FIG.

  Next, the operation when the flow rate feedback water amount control is executed in the control unit 10 will be described with reference to FIG. The process of the flowchart shown in FIG. 5 is repeatedly executed during operation of the water treatment system 1.

In step ST301 shown in FIG. 5, the control unit 10 acquires a target flow rate value Q _p ′ of the permeated water W2. The target flow rate value Q _p ′ is, for example, a set value that is input to the memory of the control unit 10 by a system administrator via a user interface (not shown).

In the flow rate feedback water amount control of the second embodiment (described later), the target flow rate value Q _p ′ acquired by the control unit 10A is set in step ST502, step ST506 or step ST508 of the flowchart shown in FIG. 8 (described later). The target flow rate is

In step ST 302, the control unit 10 determines whether the time count _{t 2} by ITU has reached the control cycle Δt ₂ (100ms). In this step ST 302, the control unit 10, when the time measurement by the ITU is determined to have reached the Delta] t ₂ (YES), the process proceeds to step ST 303. Further, in step ST 302, the control unit 10, when the time measurement by the ITU is determined not to reach the Delta] t ₂ (NO), the process returns to the step ST 302.

Step ST 303: In (step ST 302 YES judgment), the control unit 10 acquires the detected flow rate value _{Q p} of the permeate W2 detected by the flow sensor 7 as a feedback value.

In step ST 304, the control unit 10, the detected flow value obtained in step ST 303 (feedback value) _{Q p} and, as difference between the target flow rate value _{Q p} 'obtained in step ST301 becomes zero, velocity type digital PID The operation amount _Un is calculated by an algorithm. In the speed type digital PID algorithm, a change amount ΔU _n of the operation amount is calculated every control cycle Δt ₂ (100 ms), and this is added to the operation amount U _n−1 at the time of the previous control cycle to thereby calculate the current operation amount. to determine the U _n.

An arithmetic expression used for the velocity type digital PID algorithm is expressed by the following expressions (2a) and (2b).
_{ΔU n = K p {(e} n -e n-1) + (Δt 2 / T i) × e n + (T d / Δt 2) × (e n -2e n-1 + e n-2)} ( 2a)
U _n = U _n-1 + ΔU _n (2b)

In Expression (2a) and Expression (2b), Δt ₂ : Control period, U _n : Current operation amount, U _n-1 : Operation amount at the previous control period, ΔU _n : Operation amount from the previous time to this time Change, e _n : magnitude of current deviation, e _n-1 : magnitude of deviation at the previous control cycle, e _n-2 : magnitude of deviation at the previous control cycle, K _p : proportional gain , T _i : integration time, T _d : differentiation time. The size e _n of the current deviation is obtained by the following formula (3).
e _n = Q _p ′ −Q _p (3)

In step ST305, the control unit 10 uses the current operation amount U _n and the maximum drive frequency F ′ (set value of 50 Hz or 60 Hz) of the pressurizing pump 2 to pressurize according to the following equation (4). The drive frequency F [Hz] of the pump 2 is calculated.
F = U _n / 2 × F ′ (4)

In step ST306, the control unit 10 converts the calculated value of the drive frequency F into a corresponding current value signal (4 to 20 mA). The output value I [mA] of the current value signal is calculated by, for example, the following equation (5). When the drive frequency F is zero, I = 4 mA, and when the drive frequency F is the maximum drive frequency F ′, I = 20 mA.
I = F / F ′ × 16 + 4 (5)

  In step ST307, control unit 10 outputs the converted current value signal to inverter 3. Thereby, the process of this flowchart is complete | finished (it returns to step ST101).

  In step ST307, when the control unit 10 outputs a current value signal to the inverter 3, the inverter 3 supplies the driving power converted to the frequency specified by the input current value signal to the pressurizing pump 2. As a result, the pressurizing pump 2 is driven at a rotational speed corresponding to the driving frequency input from the inverter 3. The flow rate feedback water amount control described above may be executed at least during normal operation of the EDI device 5.

  Next, the operation in the case where the control unit 10 performs the recovery rate control of the RO membrane module 4 will be described with reference to the flowchart shown in FIG. The process of the flowchart shown in FIG. 6 is repeatedly executed during operation of the water treatment system 1.

In step ST401 shown in FIG. 6, the control unit 10 obtains a target flow rate value Q _p ′ of the permeated water W2. This target flow rate value Q _p ′ is the same as the set value acquired in step ST301 of the flowchart shown in FIG.

In the flow rate feedback water amount control of the second embodiment (described later), the target flow rate value Q _p ′ acquired by the control unit 10A is the target flow rate set in step ST502, step ST506 or step ST508 of the flowchart shown in FIG. Value.

  In step ST402, the control unit 10 acquires the recovery rate R of the RO membrane module 4. This recovery rate R is the recovery rate set in step ST202 or step ST203 of the flowchart shown in FIG.

  In the recovery rate control of the second embodiment (described later), the recovery rate R acquired by the control unit 10A is the recovery rate set in step ST503 or step ST507 of the flowchart shown in FIG. 8 (described later).

In step ST 403, the control unit 10 based on the recoveries R obtained in the target flow rate value _{Q p} 'and Step ST402 acquired in step ST 401, the waste water flow rate _{Q c} of the first concentrated water W3, the above Expression (1 ).

In step ST 404, the control unit 10, actual wastewater flow rate _{Q d} of the first concentrated water W3 controls the first drain valve 11 to the third drain valve 13 so that the waste water flow rate _{Q c} calculated in step ST 403. Thereby, the process of this flowchart is complete | finished (it returns to step ST401).

  According to the water treatment system 1 which concerns on 1st Embodiment mentioned above, the following effects are acquired, for example.

  In the water treatment system 1 according to the first embodiment, the control unit 10 switches the flow channel unit to the first flow channel during the normal operation of the EDI device 5, and the second flow channel unit during the regeneration operation of the EDI device 5. Switch to the flow path.

  According to this, during the normal operation of the EDI device 5, the first treated water W4 as pure water is produced by the EDI device 5. Further, during the regeneration operation of the EDI device 5, the second treated water W6 as pure water is produced by the CP device 6. Therefore, even during the regeneration operation of the EDI device 5, the purified water can be continuously produced without interrupting the purification process of the permeated water W2. Therefore, according to the water treatment system 1 according to the first embodiment, pure water can be continuously and stably supplied to the demand point even during the regeneration operation of the EDI device 5 with a simple system configuration.

  Further, when the EDI apparatus 5 is in a normal operation and the detected silica concentration value of the silica concentration sensor 8 is equal to or higher than a preset reference silica concentration value, the control unit 10 sets the flow channel portion to the first flow channel. Is switched to the second flow path, and the second treated water W6 as pure water is produced by the CP device 6. In this way, the control unit 10 switches the flow channel unit to the second flow channel when silica leaks into the permeated water W2 and the water quality deteriorates even during normal operation (waiting for regeneration operation). Then, the permeated water W2 is circulated to the CP device 6. Therefore, it is possible to suppress the accumulation of silica, which is a weak electrolyte, in the ion exchanger of the EDI apparatus 5 due to the permeated water W2 in which the silica leaks and the water quality deteriorates.

  Further, the control unit 10 sets the flow path unit to the first flow path when the detected carbonic acid concentration value of the carbonic acid concentration sensor 9 becomes equal to or higher than a preset reference carbonic acid concentration value during normal operation of the EDI device 5. To the second flow path. In this way, the control unit 10 switches the flow path unit to the second flow path when carbon dioxide leaks into the permeated water W2 and the water quality deteriorates even during normal operation (waiting for regeneration operation). Then, the permeated water W2 is circulated to the CP device 6. Therefore, it is possible to suppress the accumulation of carbon dioxide, which is a weak electrolyte, in the ion exchanger of the EDI device 5 due to the permeated water W2 whose water quality has deteriorated due to leakage of carbon dioxide.

  In addition, the control unit 10 performs flow rate feedback water amount control during operation of the EDI device 5 (during normal operation and regeneration operation). For this reason, the permeated water W2 having a stable flow rate can be produced during the operation of the EDI device 5. In addition, as will be described later, even when the recovery rate of the RO membrane module 4 is lowered during the regeneration operation of the EDI device 5, the permeated water W2 having the same flow rate as that during the normal operation can be produced.

  Further, during the regeneration operation of the EDI device 5, the control unit 10 lowers the recovery rate of the RO membrane module 4 than during the normal operation, and the actual drainage flow rate of the first concentrated water W3 is during the normal operation of the EDI device 5. The first drain valve 11 to the third drain valve 13 are controlled so as to be larger than the target discharge flow rate set to.

  In this way, during the regeneration operation of the EDI apparatus 5, by reducing the recovery rate of the RO membrane module 4 and increasing the actual drainage flow rate of the first concentrated water W3, silica, carbon dioxide, etc. leaking into the permeated water W2 The amount of ions can be reduced and the purity of the permeated water W2 can be increased. Thereby, highly purified pure water can be manufactured, suppressing the fall of the removal capability of CP apparatus 6. FIG.

  In the water treatment system 1 according to the first embodiment, the EDI device 5 and the CP device 6 are connected in series during normal operation. For this reason, during normal operation, the first treated water W4 produced by the EDI device 5 is further desalted in the subsequent CP device 6 and becomes pure water with high purity in which leakage of ions is suppressed. Therefore, according to the configuration of the first embodiment, pure water with higher purity can be produced.

  In the configuration of the first embodiment, the desalination process is performed by the CP device 6 not only during the regeneration operation of the EDI device 5 but also during the normal operation. Therefore, there is a concern that the removal capability of the CP device 6 is lowered. However, the first treated water W4 supplied to the CP device 6 is pure water having a high purity that has been desalted in the EDI device 5. For this reason, the decrease in the removal capability of the CP device 6 is negligible in practical use.

(Second Embodiment)
Next, a water treatment system 1A according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is an overall configuration diagram of a water treatment system 1A according to the second embodiment. In the second embodiment, differences from the first embodiment will be mainly described. Therefore, the same reference numerals are given to the same (or equivalent) configurations as in the first embodiment, and the description thereof is omitted as appropriate. The description of the first embodiment is used for configurations and the like not described in the second embodiment.

  As shown in FIG. 7, the water treatment system 1A according to the second embodiment includes a pressurizing pump 2, an inverter 3, an RO membrane module 4, an EDI device 5, a CP device 6, and water supply as a storage tank. A tank 16. The water treatment system 1A includes a flow rate sensor 7, a silica concentration sensor 8, a carbonic acid concentration sensor 9, a water level sensor 17 as a water level detection means, a control unit 10A, and first to third drain valves. 13, a first switching valve 14, and a second switching valve 15.

  The water treatment system 1A includes a first water line L1 to a fifth water line L5, a first concentrated water line L6, a second concentrated water line L7, a water supply line L8, and first drainage lines L11 to L11. A third drain line L13.

  As shown in FIG. 7, the water treatment system 1 </ b> A according to the second embodiment includes a water supply tank 16 on the downstream side of the CP device 6 in the configuration of the water treatment system 1 according to the first embodiment. Other basic system configurations are the same as those in the first embodiment (see FIG. 1).

  The water supply tank 16 is a tank that stores the second treated water W6 produced by the CP device 6 as pure water W7. The downstream end of the fourth water passage line L4 is connected to the water supply tank 16. The second treated water W6 produced by the CP device 6 is sent to the water supply tank 16 through the fourth water passage line L4. Moreover, the water supply tank 16 is connected to the demand location via the water supply line L8. The pure water W7 stored in the water supply tank 16 is sent to the demand point via the water supply line L8.

  In addition, it is preferable to take measures such as shielding the water tank 16 with nitrogen gas so that carbon dioxide gas does not dissolve in the stored pure water W7.

  The water level sensor 17 is a device that detects the water level of the pure water W7 (second treated water W6) stored in the water supply tank 16. The water level sensor 17 is connected to the water supply tank 16 via a detection line (reference number omitted). The water level sensor 17 is electrically connected to the control unit 10A. The water level of the water supply tank 16 detected by the water level sensor 17 (hereinafter also referred to as “detected water level value”) is transmitted as a detection signal to the control unit 10A.

  The control unit 10A is configured by a microprocessor (not shown) including a CPU and a memory. When the detected water level value W of the water level sensor 17 is equal to or higher than a preset reference storage water level value H in the flow rate feedback water amount control, the control unit 10A sets the target flow rate value of the permeated water W2 during the regeneration operation of the EDI device 5. The EDI device 5 is set lower than the target flow rate value of the permeated water W2 during normal operation.

  Further, the control unit 10A sets the recovery rate of the RO membrane module 4 to the normal recovery rate (80%) during the normal operation of the EDI device 5. Further, the control unit 10A sets the recovery rate of the RO membrane module 4 to a lower recovery rate (60%) than usual during the regeneration operation. The recovery rate control of the RO membrane module 4 by the control unit 10A is the same as in the first embodiment (see FIG. 4).

  Since other functions of the control unit 10A are the same as those of the control unit 10 of the first embodiment, description thereof is omitted. For example, when the detected silica concentration value becomes equal to or higher than the reference silica concentration value during normal operation of the EDI apparatus 5, and when the detected carbon dioxide concentration value becomes equal to or higher than the reference carbonic acid concentration value, the control unit 10A Similar to the control unit 10 of the first embodiment, the flow path unit is switched from the first flow path to the second flow path.

  Next, the operation when the target flow rate value and the recovery rate are set in the control unit 10A will be described with reference to FIG. FIG. 8 is a flowchart showing a processing procedure when the control unit 10 sets the target flow rate value and the recovery rate of the permeated water W2. Note that the processing of the flowchart shown in FIG. 8 is repeatedly executed during operation of the water treatment system 1.

  In step ST501 shown in FIG. 8, the control unit 10A determines whether or not the water treatment system 1 is in normal operation. In step ST501, when the control unit 10A determines that the normal operation is being performed (YES), the process proceeds to step ST502. In Step ST501, when the control unit 10A determines that the normal operation is not being performed (NO), that is, the regeneration operation is being performed, the process proceeds to Step ST504.

  In step ST502 (step ST501: YES determination), the control unit 10A sets the flow rate of the permeated water W2 manufactured by the RO membrane module 4 to the first target flow rate value during normal operation.

  In Step ST503, the control unit 10A sets the recovery rate of the RO membrane module 4 to 80% during normal operation. Thereby, the process of this flowchart is complete | finished (it returns to step ST501). Thus, 10 A of control parts will set the target flow rate value and collection | recovery rate of the permeated water W2 to the value at the time of normal operation if it is during normal operation.

  On the other hand, in step ST504 (step ST501: NO determination), the control unit 10A acquires the detected water level value W of the water level sensor 17.

  In step ST505, the control unit 10A determines whether or not the detected water level value W is greater than or equal to a preset reference stored water level value H. In step ST505, when the control unit 10A determines that the detected water level value W ≧ the reference stored water level value H (YES), the process proceeds to step ST506. In Step ST505, when the control unit 10A determines that the detected water level value W <the reference stored water level value H (NO), the process proceeds to Step ST508.

  In step ST506 (step ST505: YES determination), the control unit 10A sets the flow rate of the permeated water W2 manufactured by the RO membrane module 4 to the second target flow rate value during the regeneration operation. The second target flow value is a flow value lower than the first target flow value during normal operation, and is selected from a range of 25 to 75% of the first target flow value, for example.

  In Step ST507, the control unit 10A sets the recovery rate of the RO membrane module 4 to 60%, which is lower than that during normal operation. Thereby, the process of this flowchart is complete | finished (it returns to step ST501). As described above, during the regeneration operation, when the water storage amount of the water supply tank 16 is sufficient (the reference storage water level value H or more), the removal capability of the CP device 6 is reduced by lowering the target flow rate value than in the normal operation. Can be suppressed.

  On the other hand, in step ST508 (step ST505: NO determination), the control unit 10A sets the flow rate of the permeated water W2 manufactured by the RO membrane module 4 to the first target flow rate value during normal operation. Thus, even during the regeneration operation, when the amount of water stored in the water supply tank 16 is small (less than the reference stored water level value H), the target flow rate value during normal operation is set. Thereby, supply of the pure water W7 to a demand location can be maintained as much as possible. After control part 10A performs processing of Step ST508, processing shifts to Step ST507.

  In the second embodiment, the switching of the flow path unit, the flow rate feedback water amount control, and the recovery rate control by the control unit 10A are the same as those in the first embodiment (see FIGS. 3, 5, and 6), so the description will be given. Omitted.

  According to 1 A of water treatment systems which concern on 2nd Embodiment mentioned above, the effect similar to 1st Embodiment is acquired. In particular, in the water treatment system 1A according to the second embodiment, for example, the following specific effects can be obtained.

  In the water treatment system 1A according to the second embodiment, the control unit 10A switches the flow channel unit to the first flow channel during the normal operation of the EDI device 5, and the second flow channel unit during the regeneration operation of the EDI device 5. Switch to the flow path.

  According to this, during the normal operation of the EDI device 5, the first treated water W4 as pure water is produced by the EDI device 5. Further, during the regeneration operation of the EDI device 5, the second treated water W6 as pure water is produced by the CP device 6. Therefore, even during the regeneration operation of the EDI device 5, pure water can be continuously produced without interrupting the desalting treatment of the permeated water W2. Therefore, according to the water treatment system 1A according to the second embodiment, pure water can be continuously and stably supplied to the demand point even during the regeneration operation of the EDI device 5.

  The water treatment system 1 </ b> A includes a water supply tank 16 on the downstream side of the CP device 6. For this reason, even if fluctuation | variation arises in the water quantity of the permeated water W2 manufactured with the RO membrane module 4, the pure water W7 of the stable flow volume can be supplied to a demand location within the range of the amount of stored water.

  In addition, when the detected water level value W of the water supply tank 16 is equal to or higher than the reference stored water level value H during the regeneration operation of the EDI device 5, the control unit 10 </ b> A lowers the target flow rate value compared to the normal operation to reduce the flow rate feedback water amount. Take control. As described above, when the amount of water stored in the water supply tank 16 is sufficient (reference storage water level value H or more), the target flow rate value is lowered compared to that during normal operation, thereby suppressing the reduction in the removal capability of the CP device 6. be able to.

(Third embodiment)
Next, a water treatment system 1B according to a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 9 is an overall configuration diagram of a water treatment system 1B according to the third embodiment. FIGS. 10A and 10B are explanatory views showing the first flow path and the second flow path of the water treatment system 1B. In the third embodiment, differences from the first embodiment will be mainly described. Therefore, the same reference numerals are given to the same (or equivalent) configurations as in the first embodiment, and the description thereof is omitted as appropriate. The description of the first embodiment is used for configurations that are not described in the third embodiment.

  As shown in FIG. 9, the water treatment system 1 </ b> B according to the third embodiment includes a pressurizing pump 2, an inverter 3, an RO membrane module 4, an EDI device 5, and a CP device 6. The water treatment system 1A includes a flow sensor 7, a silica concentration sensor 8, a carbonic acid concentration sensor 9, a control unit 10B, a first drain valve 11 to a third drain valve 13, and a third switching valve 18. And a fourth switching valve 19.

  Further, the water treatment system 1B includes a first water passage line L1 to a third water passage line L3, a first concentrated water line L6, a second concentrated water line L7, a sixth water passage line L9, and a first drainage. A line L11 to a third drain line L13.

  The 3rd switching valve 18, the 4th switching valve 19, the 2nd water flow line L2, the 3rd water flow line L3, and the 6th water flow line L9 mentioned above comprise the flow-path part in this embodiment.

  As shown in FIG. 9, the water treatment system 1B according to the third embodiment includes a sixth water passage line L9. The sixth water flow line L9 causes the EDI device 5 to flow through the permeated water W2 flowing through the second water flow line L2 when the flow path unit is switched to the fourth flow path (described later) by the control unit 10B. The bypass line is circulated to the CP device 6. The 2nd treated water W6 manufactured with CP device 6 joins the 3rd water line L3 via the 6th water line L9.

  The upstream end of the sixth water line L9 is connected to the second water line L2 at the connection portion J9. The third switching valve 18 is provided between the connection portion J9 and the CP device 6. Further, the downstream end of the sixth water passage line L9 is connected to the third water passage line L3 via the fourth switching valve 19. The 4th switching valve 19 is provided in the downstream of the EDI apparatus 5 in the 3rd water flow line L3.

  The third switching valve 18 is a flow path for allowing the permeated water W2 produced by the RO membrane module 4 to flow to the EDI device 5 via the second water passage line L2, or the permeated water W2 produced by the RO membrane module 4. Is a valve that can be switched to a flow path that circulates to the CP device 6 via the sixth water flow line L9. The third switching valve 18 is configured by, for example, an electric or electromagnetic two-way valve. The third switching valve 18 is electrically connected to the control unit 10B. The opening / closing of the valve in the third switching valve 18 is controlled by a valve opening / closing signal from the control unit 10B.

  The fourth switching valve 19 is a flow path for sending the first treated water W4 produced by the EDI device 5 to the demand point via the third water flow line L3, or the second treated water produced by the CP device 6. It is a valve which can be switched to the flow path which sends W6 to a demand location via the 3rd water flow line L3. The fourth switching valve 19 is constituted by, for example, an electric or electromagnetic three-way valve. The fourth switching valve 19 is electrically connected to the control unit 10B. The opening and closing of the valve in the fourth switching valve 19 is controlled by a valve opening / closing signal from the control unit 10B.

  During the normal operation of the EDI apparatus 5, the flow path portion is switched to a third flow path (described later). In the third flow path, the permeated water W2 produced by the RO membrane module 4 flows to the EDI device 5 via the second water passage line L2.

  On the other hand, during the regeneration operation of the EDI device 5, the flow path portion is switched to the fourth flow path (described later). In the second flow path, the permeated water W2 produced by the RO membrane module 4 does not flow to the EDI device 5 but flows to the CP device 6. That is, during the regeneration operation of the EDI device 5, desalting is performed by the CP device 6 instead of the EDI device 5.

  Next, the third flow path and the fourth flow path in the water treatment system 1B will be described with reference to FIG. In FIG. 10, RO membrane module 4, EDI device 5, CP device 6, first water flow line L1 to third water flow line L3, sixth water flow line L9, second concentrated water line L7, and third switching. Only the valve 18 and the fourth switching valve 19 are shown. Moreover, in FIG. 10, the line through which the supply water W1 etc. distribute | circulate is shown as a continuous line, and the line which does not distribute | circulate is shown with a broken line. Moreover, in the 3rd switching valve 18, a valve opening is shown in white and a valve closing is shown in black. Furthermore, as for the fourth switching valve 19, the opened portion is shown in white, and the closed portion is shown in black.

  FIG. 10A is an explanatory diagram showing a third flow path of the water treatment system 1B. The third flow path is a flow path when the EDI device 5 is normally operated. The control unit 10B (not shown) controls the third switching valve 18 and the fourth switching valve 19 as follows during normal operation of the EDI device 5.

  The control unit 10B closes the third switching valve 18 and opens the two ports connected to the third water passage line L3 and the ports connected to the sixth water passage line L9 in the fourth switching valve 19. Close. Thereby, the permeated water W2 manufactured by the RO membrane module 4 flows to the EDI device 5 through the second water flow line L2 without flowing through the sixth water flow line L9. And the 1st treated water W4 manufactured with the EDI apparatus 5 is sent to a demand location via the 3rd water flow line L3.

  As described above, when the flow path portion is switched to the third flow path, the permeated water W2 produced by the RO membrane module 4 flows to the EDI device 5 via the second water flow line L2, and the EDI In the apparatus 5, the 1st treated water W4 is manufactured. And the 1st treated water W4 manufactured with the EDI apparatus 5 is sent to a downstream demand location via the 3rd water flow line L3.

  FIG. 10B is an explanatory diagram showing a fourth flow path of the water treatment system 1B. The fourth flow path is a flow path when the EDI device 5 is regenerated. The control unit 10B (not shown) controls the third switching valve 18 and the fourth switching valve 19 as follows during the regeneration operation of the EDI device 5.

  The control unit 10B opens the third switching valve 18, and at the fourth switching valve 19, connects to the port connected to the downstream side (demand point side) of the third water flow line L3 and the sixth water flow line L9. And the port connected to the upstream side (the EDI device 5 side) of the third water flow line L3 is closed. Thereby, the permeated water W2 manufactured by the RO membrane module 4 flows from the second water passage line L2 through the third switching valve 18 to the sixth water passage line L9. And the 2nd treated water W6 manufactured with CP device 6 distribute | circulates to the 3rd water flow line L3 through the 4th switching valve 19 from the 6th water flow line L9. Then, the 2nd treated water W6 is sent to a demand point via the 3rd water flow line L3.

  As described above, when the flow path portion is switched to the fourth flow path, the permeated water W2 manufactured by the RO membrane module 4 passes through the third switching valve 18 from the second water flow line L2 and passes through the sixth flow path. It distribute | circulates to the water line L9, and the 2nd treated water W6 is manufactured in CP apparatus 6. FIG. And the 2nd treated water W6 manufactured with CP device 6 distribute | circulates to the 3rd water flow line L3 through the 4th switching valve 19 from the 6th water flow line L9, and is further sent to the downstream demand point. .

  In the third embodiment, the switching of the flow path part, the setting of the recovery rate, the flow rate feedback water amount control and the recovery rate control by the control unit 10B are the same as in the first embodiment (see FIGS. 3 to 6). Description is omitted.

  According to the water treatment system 1B according to the third embodiment described above, the same effect as in the first embodiment can be obtained. In particular, in the water treatment system 1B according to the third embodiment, for example, the following specific effects can be obtained.

  In the water treatment system 1B according to the third embodiment, the control unit 10B switches the flow channel unit to the third flow channel during the normal operation of the EDI device 5, and switches the flow channel unit to the third flow channel during the regeneration operation of the EDI device 5. Switch to 4 channels.

  According to this, during the normal operation of the EDI device 5, the first treated water W4 as pure water is produced by the EDI device 5. Further, during the regeneration operation of the EDI device 5, the second treated water W6 as pure water is produced by the CP device 6. Therefore, even during the regeneration operation of the EDI device 5, pure water can be continuously produced without interrupting the desalting treatment of the permeated water W2. Therefore, according to the water treatment system 1B according to the third embodiment, pure water can be continuously and stably supplied to the demand point even during the regeneration operation of the EDI device 5 with a simple system configuration.

  Further, in the water treatment system 1B according to the third embodiment, the CP device 6 is connected in parallel to the EDI device 5. For this reason, during normal operation, the permeated water W2 produced by the RO membrane module 4 is desalted by the EDI device 5, and the CP device 6 is not used. For this reason, the fall of the removal capability of CP apparatus 6 during normal operation can be suppressed to the minimum.

  In addition, in 3rd Embodiment, it is good also as a structure which further provided the water supply tank 16 (refer FIG. 7) in the downstream of the 3rd water flow line L3. Also in 3rd Embodiment, the effect similar to 2nd Embodiment can be acquired by providing the water supply tank 16. FIG.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be implemented in various forms.

  For example, in the first and second embodiments, an example in which a two-way valve (first switching valve 14 and second switching valve 15) is used as a configuration for switching between the first flow path and the second flow path will be described. did. Not limited to this, it is also possible to use an electric or electromagnetic three-way valve (third switching valve 18 and fourth switching valve 19) as shown in the third embodiment. In this case, a three-way valve is provided at each of the connection portions J4 and J6 shown in FIG.

  Moreover, in 3rd Embodiment, the example using a three-way valve (the 3rd switching valve 18 and the 4th switching valve 19) was demonstrated as a structure for switching a 3rd flow path and a 4th flow path. Not limited to this, it is also possible to use electric or electromagnetic two-way valves (first switching valve 14 and second switching valve 15) as shown in the first and second embodiments.

  In this case, in the position of the 3rd switching valve 18 shown in FIG. 9, the 2nd water flow line L2 and the upstream edge part of the 6th water flow line L9 are connected. In addition, at the position of the fourth switching valve 19, the third water passage line L3 and the downstream end of the sixth water passage line L9 are connected. And a two-way valve is provided in the vicinity of the upstream end of the sixth water flow line L9 and in the vicinity of the downstream end thereof.

  Moreover, in 1st Embodiment-3rd Embodiment, a part of 1st concentrated water W3 which distribute | circulates the 1st concentrated water line L6 is recirculated to the 1st water flow line L1 upstream from the pressurization pump 2. It is good also as a structure which provided the concentrated water reflux line. By providing the concentrated water reflux line, the flow velocity on the membrane surface can be increased, so that the occurrence of fouling in the RO membrane module 4 can be suppressed.

  1st Embodiment-3rd Embodiment demonstrated the example which discharges | emits all the 2nd concentrated water W5 discharged | emitted from the concentration chamber 5b of the EDI apparatus 5. In FIG. However, the second concentrated water W5 has a higher purity than the supply water W1. Therefore, it is good also as a structure which provided the concentrated water return line which returns a part or all of 2nd concentrated water W5 to the upstream rather than the RO membrane module 4 in the 1st water flow line L1. By providing the concentrated water return line, the water production cost can be reduced.

  Moreover, 1st Embodiment-3rd Embodiment demonstrates the example which adjusts the waste_water | drain flow volume of the 1st concentrated water W3 in steps by selectively opening and closing the 1st drain valve 11-the 3rd drain valve 13. FIG. did. However, the configuration is not limited to this, and the drainage line may be one without branching, and a proportional control valve may be provided on this line. In that case, the control unit 10 (10A, 10B) sends a current value signal (for example, 4 to 20 mA) to each RO membrane module 4 to the proportional control valve, thereby controlling the valve opening degree. The drainage flow rate of the 1 concentrated water W3 can be adjusted.

  Moreover, in the structure provided with the proportional control valve, it is good also as a structure which provided the flow sensor in the drainage line of each RO membrane module 4. FIG. The flow rate value detected by the flow rate sensor is input to the control unit 10 (10A, 10B) as a feedback value. Thereby, the actual waste_water | drain flow volume of the 1st concentrated water W3 can be controlled more correctly.

  Moreover, 1st Embodiment-3rd Embodiment demonstrated the example which performs flow volume feedback water volume control. However, when the amount of pure water W7 used is small or when it is not necessary to maintain the flow rate of the permeated water W2 at the target flow rate value, the flow rate feedback water amount control need not always be executed. Similarly, in the first to third embodiments, the example of executing the recovery rate control has been described. However, when the quality of the supply water W1 is high or when the amount of pure water W7 used is small, the recovery rate control need not always be executed.

In the first to third embodiments, the example in which the flow path portion is switched to the second flow path or the fourth flow path mainly during the regeneration operation of the EDI device 5 has been described. However, the flow path portion may be switched to the second flow path or the fourth flow path during chemical cleaning or replacement of the EDI device 5.
Moreover, it is good also as a structure which replaces with the EDI apparatus 5 and has arrange | positioned the regenerative type mixed bed type ion exchange apparatus.

1, 1A, 1B Water treatment system 2 Pressure pump 3 Inverter 4 RO membrane module (membrane separation device)
5 EDI equipment (electric ion exchange equipment)
6 CP equipment (mixed-bed ion exchange equipment)
7 Flow rate sensor (flow rate detection means)
8 Silica concentration sensor (silica concentration detection means)
9 Carbonic acid concentration sensor (carbonic acid concentration detection means)
10, 10A, 10B Control unit 11 First drain valve (drain valve)
12 Second drain valve (drain valve)
13 Third drain valve (drain valve)
14 1st switching valve 15 2nd switching valve 16 Water supply tank (storage tank)
17 Water level sensor (water level detection means)
18 3rd switching valve 19 4th switching valve L1 1st water flow line (supply water line)
L2 2nd water line L3 3rd water line L4 4th water line L5 5th water line L6 1st concentrated water line L7 2nd concentrated water line L8 Feed water line L9 6th water line W1 Supply water W2 Permeation Water W3 First concentrated water W4 First treated water W5 Second concentrated water W6 Second treated water W7 Pure water

Claims (5)

A membrane separation device for membrane-separating feed water into permeate and concentrated water;
An electrical ion exchange device for producing a first treated water by desalting the permeated water;
A mixed bed ion exchange apparatus for producing second treated water by desalting the permeated water or the first treated water;
Silica concentration detecting means for detecting the silica concentration of the permeated water produced by the membrane separator;
(I) a first flow path for flowing the permeated water to the electric ion exchange device and for flowing the first treated water produced by the electric ion exchange device to the mixed bed ion exchange device; ) A flow path portion that can be switched to the second flow path to be circulated to the mixed bed ion exchange apparatus without being circulated to the electric ion exchange apparatus;
Control that switches the flow path portion to the first flow path during normal operation of the electrical ion exchange device, and switches the flow path portion to the second flow path during regeneration operation of the electrical ion exchange device. comprises a part, the,
When the detected silica concentration of the silica concentration detecting means is equal to or higher than a preset reference silica concentration during normal operation of the electric ion exchange device, the control unit causes the flow path portion to be the second flow path. Switch,
Water treatment system. A membrane separation device for membrane-separating feed water into permeate and concentrated water;
An electrical ion exchange device for producing a first treated water by desalting the permeated water;
A mixed bed type ion exchange device for producing a second treated water by desalting the permeated water;
Silica concentration detecting means for detecting the silica concentration of the permeated water produced by the membrane separator;
Permeated water (i) a third flow path that circulates to the electric ion exchanger without being circulated to the mixed bed ion exchanger, and (ii) the circulatory water that is not circulated to the electric ion exchanger. A flow path portion that can be switched to a fourth flow path to be circulated to the mixed bed ion exchange device;
Control that switches the flow path portion to the third flow path during normal operation of the electrical ion exchange device, and switches the flow path portion to the fourth flow path during regeneration operation of the electrical ion exchange device. comprises a part, the,
If the detected silica concentration of the silica concentration detecting means is equal to or higher than a preset reference silica concentration during normal operation of the electric ion exchange device, the control unit moves the flow channel portion into the fourth flow channel. Switch,
Water treatment system. A flow rate detecting means for detecting a flow rate of the permeated water produced by the membrane separation device and outputting a detected flow rate value corresponding to the flow rate;
A feed water line for feeding feed water to the membrane separation device;
A pressurizing pump that is driven at a rotational speed corresponding to the input driving frequency and pumps the feed water flowing through the feed water line toward the membrane separation device;
An inverter that outputs a driving frequency corresponding to the input current value signal to the pressurizing pump;
The control unit uses the velocity type digital PID algorithm so that the detected flow rate value output from the flow rate detection means becomes a preset target flow rate value at least during normal operation of the electric ion exchange device. Calculate the driving frequency of the pressure pump, and output a current value signal corresponding to the calculated value of the driving frequency to the inverter.
The water treatment system according to claim 1 or 2 . A drainage valve capable of adjusting the discharge flow rate of the concentrated water discharged from the membrane separation device,
The control unit controls the drain valve so that a drainage flow rate of the concentrated water is larger than a discharge flow rate set during a normal operation of the electrical ion exchange device during the regeneration operation of the electrical ion exchange device. Control,
The water treatment system according to any one of claims 1 to 3 . A storage tank for storing the first treated water and / or the second treated water;
Water level detection means for detecting the water level of the storage tank,
If the detected water level of the water level detection means is equal to or higher than a preset reference stored water level, the control unit sets a target flow rate value of permeated water during the regeneration operation of the electric ion exchange device to the electric ion exchange device. Set lower than the target flow rate of permeate during normal operation of
The water treatment system according to claim 3 or 4 .

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