WO2017217008A1 - Reverse osmosis membrane separation apparatus - Google Patents

Reverse osmosis membrane separation apparatus Download PDF

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Publication number
WO2017217008A1
WO2017217008A1 PCT/JP2017/005438 JP2017005438W WO2017217008A1 WO 2017217008 A1 WO2017217008 A1 WO 2017217008A1 JP 2017005438 W JP2017005438 W JP 2017005438W WO 2017217008 A1 WO2017217008 A1 WO 2017217008A1
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Prior art keywords
pressure
raw water
water
flow rate
line
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PCT/JP2017/005438
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French (fr)
Japanese (ja)
Inventor
隼人 渡邉
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三浦工業株式会社
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Publication of WO2017217008A1 publication Critical patent/WO2017217008A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/08—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/12—Controlling or regulating
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis

Definitions

  • the present invention relates to a reverse osmosis membrane separation device including a reverse osmosis membrane module.
  • This application claims priority based on Japanese Patent Application No. 2016-117381 for which it applied to Japan on June 13, 2016, and uses the content here.
  • High purity pure water that does not contain impurities is used in semiconductor manufacturing processes, cleaning of electronic parts and medical equipment, and the like.
  • This type of pure water is generally produced by subjecting raw water such as groundwater or tap water to a reverse osmosis membrane separation treatment with a reverse osmosis membrane module (hereinafter also referred to as “RO membrane module”).
  • RO membrane module a reverse osmosis membrane module
  • the water permeability coefficient of a reverse osmosis membrane made of a polymer material varies depending on the temperature. Further, the water permeation coefficient of the reverse osmosis membrane also changes due to pore clogging (hereinafter also referred to as “membrane clogging”) and deterioration due to oxidation of the material (hereinafter also referred to as “membrane degradation”).
  • the concentrated water separated by the RO membrane module is sent out from the concentrated water line connected to the primary outlet port of the RO membrane module. Moreover, the permeated water separated by the RO membrane module is sent out from the permeated water line connected to the secondary side port of the RO membrane module.
  • the concentrated water line is branched into a circulating water line and a concentrated water drainage line.
  • the circulating water line is a line that returns a part of the concentrated water sent from the concentrated water line to the merging portion of the raw water line on the upstream side of the pressurizing pump.
  • the concentrated water drainage line is a line for discharging the remaining portion of the concentrated water sent from the concentrated water line to the outside of the apparatus.
  • the raw water line is a line for supplying raw water to the RO membrane module via a pressure pump.
  • Patent Document 2 a technology for providing a constant flow valve in the concentrated water line is known in order to keep the flow rate of the concentrated water flowing through the concentrated water line constant.
  • Patent Document 2 a portion of the concentrated water that has passed through the constant flow valve flows through the circulating water line and is returned to the confluence portion of the raw water line.
  • the pressure on the secondary side of the constant flow valve is the raw water pressure of the raw water line. Therefore, when the raw water raw water pressure is high, the pressure difference between the primary side and secondary side of the constant flow valve provided in the concentrated water line becomes small, and the differential pressure obtained by subtracting the secondary side pressure from the primary side pressure is reduced. It cannot be ensured, and part of the concentrated water cannot be returned to the confluence of the raw water line via the circulating water line.
  • the reason why the raw water pressure is reduced to a predetermined constant pressure value using the pressure reducing valve is as follows.
  • the discharge pressure (operating pressure of the pressure pump, input pressure to the primary side inlet port of the RO membrane module) is controlled to be low.
  • a pressure reducing valve is used. It was necessary to reduce the raw water pressure upstream of the pressurizing pump to a predetermined constant pressure value.
  • the viscosity of the water is larger and the water permeability coefficient of the RO membrane module is lower than when the raw water temperature is high.
  • Control is performed so that the discharge pressure of the pressure pump (the operating pressure of the pressure pump, the input pressure to the primary inlet port of the RO membrane module) is increased.
  • the raw water pressure reduced by the pressure reducing valve is adjusted to a predetermined constant pressure value. Therefore, when the temperature of the raw water is low, the pressure on the primary side of the constant flow valve is sufficiently higher than the pressure on the secondary side of the constant flow valve as compared with the case where the temperature of the raw water is high.
  • the pressure on the secondary side of the constant flow valve is low because the raw water pressure is reduced.
  • the differential pressure obtained by subtracting the secondary side pressure from the primary side pressure on the primary side and secondary side of the constant flow valve compared to when the raw water temperature is high is: The predetermined differential pressure is greatly exceeded and secured with a margin.
  • the raw water pressure is increased in order to circulate toward the RO membrane module while ensuring the differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve. If it can be used effectively as it is, the power consumption of the pressurizing pump that pumps the raw water pressure to the raw water can be reduced. Therefore, reverse osmosis membrane separation that can effectively utilize the raw water pressure of raw water flowing through the raw water line while ensuring a differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve (constant flow means). An apparatus is desired.
  • the present invention relates to a reverse osmosis membrane module, a raw water line for supplying raw water to the reverse osmosis membrane module, a concentrated water line for discharging concentrated water separated by the reverse osmosis membrane module, and a concentrated water branched from the concentrated water line.
  • a reverse osmosis membrane separation device comprising a circulating water line for returning a part to the reverse osmosis membrane module and a constant flow means provided in the concentrated water line, the secondary pressure is reduced from the primary pressure of the constant flow means. It aims at providing the reverse osmosis membrane separation apparatus which can utilize effectively the raw
  • the present invention includes a reverse osmosis membrane module that separates raw water into permeated water and concentrated water, a raw water line that supplies raw water to the reverse osmosis membrane module, and a permeate that delivers permeated water separated by the reverse osmosis membrane module.
  • a raw water pressure adjusting means for adjusting a pressure of the raw water flowing through the raw water line upstream of the confluence portion, provided in the raw water line, and provided in the concentrated water line
  • Constant flow rate means for maintaining the flow rate of circulating concentrated water at a predetermined constant flow value, and a constant flow rate difference for detecting a differential pressure between a primary pressure and a secondary pressure of the constant flow rate means as a detected differential pressure value
  • a reverse osmosis membrane comprising: a pressure detection unit; and
  • a pressure pump provided in the raw water line downstream of the junction and sucking the raw water and discharging the raw water toward the reverse osmosis membrane module; and detecting a flow rate of the permeated water as a first detected flow rate value. It is preferable to include a first flow rate detection unit and a pressurization pump drive control unit that controls driving of the pressurization pump so that the first detection flow rate value becomes a preset target flow rate value.
  • a drainage flow rate adjusting means provided in the drainage line and capable of adjusting the drainage flow rate of the concentrated water discharged outside the apparatus, and a temperature detection means for detecting the temperature of the raw water, the permeated water or the concentrated water as a detected temperature value
  • a drainage control unit that controls the drainage flow rate adjusting means, and the drainage control unit is based on (i) the silica concentration determined from the silica concentration of raw water obtained in advance and the detected temperature value of the temperature detecting means.
  • Calculating the allowable concentration rate of silica in the concentrated water (ii) calculating the drainage flow rate from the calculated value of the allowable concentration rate and the target flow rate value of the permeate, and (iii) the actual drainage flow rate of the concentrated water is It is preferable to control the drainage flow rate adjusting means so as to obtain a calculated value of the drainage flow rate.
  • the drainage flow rate adjusting means includes a proportional control valve that detects the drainage flow rate of the concentrated water as a second detected flow rate value, and the drainage control unit is configured such that the second detected flow rate value is It is preferable to adjust the valve opening degree of the proportional control valve so that the drainage flow rate is calculated.
  • a reverse osmosis membrane module a reverse osmosis membrane module, a raw water line for supplying raw water to the reverse osmosis membrane module, a concentrated water line for discharging concentrated water separated by the reverse osmosis membrane module, and a branching and concentration from the concentrated water line
  • a reverse osmosis membrane separation device comprising a circulating water line for returning a part of water to the reverse osmosis membrane module, and a constant flow means provided in the concentrated water line
  • the secondary pressure is changed from the primary pressure of the constant flow means to the secondary osmosis membrane separation device. It is possible to provide a reverse osmosis membrane separation device that can effectively use the raw water pressure of raw water flowing through the raw water line while ensuring a reduced differential pressure.
  • 1 is an overall configuration diagram of a reverse osmosis membrane separation device 1 according to an embodiment.
  • 4 is a flowchart showing a processing procedure in the case where a differential pressure obtained by subtracting a secondary pressure from a primary pressure of the constant flow valve 5 is adjusted by controlling the raw water proportional control valve 14 in the control unit 30.
  • FIG. 1 is an overall configuration diagram of a reverse osmosis membrane separation device 1 according to an embodiment.
  • the reverse osmosis membrane separation device 1 according to the present embodiment is applied to, for example, a pure water production system that produces pure water from fresh water.
  • the reverse osmosis membrane separation device 1 includes a raw water pump 12, a raw water side inverter 13, a raw water proportional control valve 14 as a raw water pressure adjusting means, a pressurizing pump 2, Pressurizing side inverter 3, RO membrane module 4 as reverse osmosis membrane module, constant flow valve 5 as constant flow means, check valve 6, and drain proportional control valve 8 (proportional control valve) as drain flow rate adjusting means ), A flow path switching valve 15, and a control unit 30.
  • the reverse osmosis membrane separation device 1 includes a secondary pressure sensor PS2 as a constant flow rate differential pressure detection unit, a primary pressure sensor PS1 as a constant flow rate differential pressure detection unit, a discharge pressure sensor PS3, and a first flow rate.
  • a first flow rate sensor FM1 as detection means and a second flow rate sensor FM2 as second flow rate detection means are provided. Note that illustration of electrical connection lines between the control unit 30 and the controlled device is omitted.
  • the reverse osmosis membrane separation apparatus 1 includes a raw water line L1, a permeate water line L2, a concentrated water line L3, a circulating water line L4, a drainage line L5, and a permeate return line L6.
  • 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 raw water line L1 is a line for supplying the raw water W1 to the RO membrane module 4.
  • the upstream end of the raw water line L1 is connected to a supply source (not shown) of the raw water W1.
  • the downstream end of the raw water line L ⁇ b> 1 is connected to the primary inlet port of the RO membrane module 4.
  • the raw water pump 12, the raw water proportional control valve 14, the secondary pressure sensor PS2, the merging section J2, the pressurizing pump 2, the discharge pressure sensor PS3, and the RO membrane module 4 is provided.
  • the raw water W1 flowing through the raw water line L1 is not limited to the raw water directly supplied from the raw water W1 supply source (not shown), but, for example, the raw water W1 is filtered by a filtration device (iron removal manganese removal device, activated carbon filtration device). Etc.), and raw water pretreated by a pretreatment device such as a water softening device is also included.
  • a filtration device iron removal manganese removal device, activated carbon filtration device.
  • Etc. iron removal manganese removal device, activated carbon filtration device
  • a pretreatment device such as a water softening device
  • the raw water pump 12 is a device that sucks the raw water W1 flowing through the raw water line L1 and pumps (discharges) the raw water W1 toward the pressurizing pump 2.
  • the raw water pump 12 is supplied with driving power whose frequency is converted from the raw water side inverter 13.
  • the raw water pump 12 is driven at a rotational speed corresponding to the frequency (hereinafter also referred to as “drive frequency”) of the supplied drive power (input).
  • the raw water side inverter 13 is an electric circuit (or a device having the circuit) for supplying the raw water pump 12 with driving power whose frequency has been converted.
  • the raw water side inverter 13 is electrically connected to the control unit 30.
  • a command signal is input from the control unit 30 to the raw water side inverter 13.
  • the raw water side inverter 13 outputs driving power having a driving frequency corresponding to the command signal (current value signal or voltage value signal) input by the control unit 30 to the raw water pump 12.
  • the control unit 30 controls the raw water side inverter 13 so that the raw water pump 12 discharges the raw water W1 at a predetermined constant pressure value.
  • the constant pressure value of the raw water W1 applied by the raw water pump 12 is set to a pressure value at which the raw water W1 flowing through the raw water line L1 can be supplied to the pressurizing pump 2.
  • the raw water pressure of the raw water W1 becomes a constant pressure value.
  • the raw water pressure of the raw water W1 is set to a constant pressure value between 0.2 and 0.5 MPa, for example.
  • natural water pump 12 was provided in the raw
  • the raw water proportional control valve 14 is provided in the raw water line L1 upstream from the junction J2.
  • the raw water proportional control valve 14 is a valve that adjusts the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2.
  • the raw water line L1 on the upstream side of the junction J2 is connected to the circulating water line L4 via the junction J2.
  • the circulating water line L4 is connected to the concentrated water line L3 via the connection portion J1.
  • the connection portion J1 and the secondary side of the constant flow valve 5 are connected. That is, it can be considered that the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2 is the same as the pressure on the secondary side of the constant flow valve 5.
  • the raw water proportional control valve 14 adjusts the raw water pressure of the raw water W1 flowing through the raw water line L1 upstream of the junction J2, thereby adjusting the secondary pressure of the constant flow valve 5 (described later) to a predetermined set pressure.
  • the differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5 (hereinafter also referred to as “constant flow valve differential pressure”) is adjusted.
  • the secondary pressure of the constant flow valve 5 is detected as a detected secondary pressure value by a secondary pressure sensor PS2 (described later) disposed between the raw water proportional control valve 14 and the junction J2.
  • the raw water proportional control valve 14 is electrically connected to the control unit 30.
  • the valve opening degree of the raw water proportional control valve 14 is controlled by a drive signal transmitted from the control unit 30.
  • a current value signal for example, 4 to 20 mA
  • the flow resistance that is, pressure loss
  • the raw water proportional control valve 14 adjusts the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2.
  • the raw water W1 flowing upstream of the raw water proportional control valve 14 has a raw water pressure of a predetermined constant pressure value as described above. Therefore, the raw water pressure downstream of the raw water proportional control valve 14 adjusted by the raw water proportional control valve 14 is equal to or lower than a predetermined constant pressure value of the raw water pressure discharged by the raw water pump 12 by the control unit 30 described later. To be controlled.
  • the secondary side pressure sensor PS2 is arranged between the raw water proportional control valve 14 and the junction J2 in the raw water line L1.
  • the secondary side pressure sensor PS2 is a device that detects the secondary side pressure of the constant flow valve 5 as a detected secondary side pressure value.
  • the pressure of the raw water W1 flowing through the raw water line L1 upstream of the junction J2 and downstream of the raw water proportional control valve 14 is the same as the pressure on the secondary side of the constant flow valve 5. . Therefore, the secondary pressure sensor PS2 detects the pressure of the raw water W1 between the raw water proportional control valve 14 and the junction J2, thereby detecting the secondary pressure of the constant flow valve 5 and the secondary pressure value.
  • the secondary pressure sensor PS2 is electrically connected to the control unit 30. The detected secondary pressure value detected by the secondary pressure sensor PS2 is transmitted to the control unit 30 as a detection signal.
  • the detection position of the secondary side pressure of the constant flow valve 5 by the secondary side pressure sensor PS2 is the position between the raw water proportional control valve 14 and the merging portion J2. Not limited to.
  • the secondary pressure sensor PS2 is not limited to this position as long as the secondary pressure of the constant flow valve 5 can be detected.
  • the pressure on the secondary side of the constant flow valve 5 is the pressure of the raw water W1 flowing between the raw water proportional control valve 14 and the pressurizing pump 2 in the raw water line L1, and the connection with the constant flow valve 5 in the concentrated water line L3.
  • the pressure of the concentrated water W3 flowing between J1 and the pressure of a part W31 of the concentrated water W3 flowing through the circulating water line L4, and the connection between the connecting portion J1 and the drainage proportional control valve 8 in the drainage line L5 The pressure of the remaining portion W32 of the concentrated water W3 is the same. Therefore, if the detection position of the secondary side pressure sensor PS2 is a position where the pressure on the secondary side of the constant flow valve 5 can be detected, for example, between the constant flow valve 5 and the connection portion J1 in the concentrated water line L3. A position, the position between the connection part J1 and the junction part J2 in the circulating water line L4, etc. may be sufficient.
  • the pressurizing pump 2 is provided in the raw water line L1 on the downstream side of the junction J2.
  • the pressurizing pump 2 is a device that sucks raw water W1 flowing through the raw water line L1 and feeds (discharges) the raw water W1 to the RO membrane module 4 in the raw water line L1 downstream of the junction J2.
  • the pressurizing pump 2 is supplied with driving power whose frequency is converted from the pressurizing side inverter 3.
  • the pressurizing pump 2 is driven at a rotational speed corresponding to the frequency (hereinafter also referred to as “driving frequency”) of the driving power supplied (input).
  • the pressurizing side inverter 3 is an electric circuit (or a device having the circuit) that supplies the pressurizing pump 2 with driving power whose frequency is converted.
  • the pressurizing side inverter 3 is electrically connected to the control unit 30.
  • a command signal is input from the control unit 30 to the pressure side inverter 3.
  • the pressurizing side inverter 3 outputs driving power having a driving frequency corresponding to the command signal (current value signal or voltage value signal) input by the control unit 30 to the pressurizing pump 2.
  • the discharge pressure sensor PS3 is a device that detects the discharge pressure (operating pressure) of the pressure pump 2 as a detected discharge pressure value.
  • the discharge pressure sensor PS3 is disposed in the vicinity of the discharge side of the pressure pump 2.
  • the pressure of the raw water W ⁇ b> 1 immediately after being discharged from the pressurizing pump 2 is set as the discharge pressure of the pressurizing pump 2.
  • the discharge pressure sensor PS3 is electrically connected to the control unit 30.
  • the detected discharge pressure value of the raw water W1 detected by the discharge pressure sensor PS3 is transmitted to the control unit 30 as a detection signal.
  • the discharge pressure sensor PS3 Pressure feedback water amount control (described later) executed using the detected discharge pressure value can be executed as a backup.
  • the present embodiment includes a discharge pressure sensor PS3 that acquires the discharge pressure value (operating pressure value) of the pressurizing pump 2 for this backup.
  • the RO membrane module 4 is a facility for subjecting the raw water W1 discharged from the pressure pump 2 to membrane separation treatment into permeated water W2 from which dissolved salts have been removed and concentrated water W3 from which dissolved salts have been concentrated.
  • the RO membrane module 4 includes a single or a plurality of RO membrane elements (not shown). The RO membrane module 4 performs membrane separation treatment on the raw water W1 with these RO membrane elements to produce permeated water W2 and concentrated water W3.
  • Permeate water line L2 is a line for sending permeate water W2 separated by RO membrane module 4.
  • the upstream end of the permeate line L2 is connected to the secondary port of the RO membrane module 4.
  • the downstream end of the permeate line L2 is connected to a device or the like at the demand point.
  • the permeate line L2 is provided with a flow path switching valve 15 and a first flow rate sensor FM1.
  • the flow path switching valve 15 branches the permeated water W2 separated by the RO membrane module 4 from the flow path (water sampling flow path) side to send to a device or the like at the demand point or from the permeated water line L2, and returns the permeated water. This is a valve that can be switched to the flow path (circulation flow path) side that circulates toward the raw water line L1 upstream of the RO membrane module 4 via the line L6.
  • the flow path switching valve 15 is configured by, for example, an electric or electromagnetic three-way valve.
  • the flow path switching valve 15 is electrically connected to the control unit 30. Switching of the flow path in the flow path switching valve 15 is controlled by a flow path switching signal transmitted from the control unit 30.
  • the permeated water return line L6 is a line that returns the permeated water W2 sent to the permeated water line L2 to the upstream side of the pressurizing pump 2 in the raw water line L1 during the flushing operation.
  • the upstream end of the permeate return line L6 is connected to the flow path switching valve 15.
  • the downstream end of the permeate return line L6 is connected to the raw water line L1 at the connection J3.
  • the connection portion J3 is disposed between the junction portion J2 and the pressure pump 2.
  • a check valve 7 is provided in the permeate return line L6.
  • the flow path switching valve 15 is switched to the water sampling flow path side in order to send the permeated water W2 separated by the RO membrane module 4 to a device or the like at the demand point. It is controlled by the control unit 30.
  • the flow path switching valve 15 is controlled by the control unit 30 as follows when the reverse osmosis membrane separation device 1 is started or when the flushing operation is executed. At the time of start-up, control is performed so that the flow path switching valve 15 is switched to the circulation flow path side in order to supply stable water to the apparatus or the like at the demand point from the start of the apparatus. Further, flushing is periodically performed to prevent clogging due to adhesion of dirt on the membrane of the RO membrane module 4. At that time, the pressure switching pump 15 is operated for a predetermined time in a state where the flow path switching valve 15 is controlled to be switched to the circulation flow path side and the drainage proportional control valve 8 is controlled to be in the open state. Thereby, the dirt adhering to the membrane of the RO membrane module 4 can be removed.
  • 1st flow sensor FM1 is an apparatus which detects the flow volume of the permeated water W2 which distribute
  • the first flow sensor FM1 is connected to the permeate line L2.
  • the first flow sensor FM1 is electrically connected to the control unit 30.
  • the first detected flow rate value of the permeated water W2 detected by the first flow rate sensor FM1 is transmitted to the control unit 30 as a pulse signal.
  • a pulse transmission type flow rate sensor in which an axial flow impeller or a tangential impeller (not shown) is disposed in the flow path housing can be used.
  • the concentrated water line L3 is a line for sending the concentrated water W3 separated by the RO membrane module 4.
  • the upstream end of the concentrated water line L3 is connected to the primary outlet port of the RO membrane module 4. Further, the downstream side of the concentrated water line L3 branches to the circulating water line L4 and the drainage line L5 at the connection portion J1.
  • the concentrated water line L3 is provided with a primary pressure sensor PS1, a constant flow valve 5, and a connecting portion J1 in order from the upstream side to the downstream side.
  • the primary side pressure sensor PS1 is a device that detects the primary side pressure of the constant flow valve 5 as a detected primary side pressure value.
  • the primary side pressure sensor PS1 is disposed between the RO membrane module 4 and the constant flow valve 5 in the concentrated water line L3.
  • the primary side pressure sensor PS1 is electrically connected to the control unit 30.
  • the detected primary pressure value of the raw water W1 detected by the primary pressure sensor PS1 is transmitted to the control unit 30 as a detection signal.
  • the constant flow valve 5 is a device that adjusts the flow rate of the concentrated water W3 flowing through the concentrated water line L3 so as to maintain a predetermined constant flow rate value.
  • the constant flow value held in the constant flow valve 5 is a concept having a range in the constant flow value, and is not limited to the target flow value in the constant flow valve.
  • the constant flow mechanism includes those having an adjustment error of about ⁇ 10% with respect to the target flow rate value.
  • the constant flow valve 5 holds a constant flow value without requiring auxiliary power or external operation, and includes, for example, what is called by the name of a water governor.
  • the constant flow valve 5 may be operated by auxiliary power or an external operation to hold a constant flow value.
  • the circulating water line L4 is a line branched from the concentrated water line L3, and a part W31 of the concentrated water W3 separated by the RO membrane module 4 is more than the RO membrane module 4 and the pressure pump 2 in the raw water line L1. This line is returned to the upstream junction J2.
  • the upstream end of the circulating water line L4 is connected to the concentrated water line L3 at the connecting portion J1. Further, the downstream end of the circulating water line L4 is connected to the raw water line L1 at the junction J2.
  • a check valve 6 is provided in the circulating water line L4.
  • the drainage line L5 is a line that is branched from the concentrated water line L3 at the connection portion J1 and discharges the remaining portion W32 of the concentrated water W3 separated by the RO membrane module 4 to the outside of the apparatus (outside the system).
  • the drainage line L5 is provided with a second flow rate sensor FM2 and a drainage proportional control valve 8 as drainage flow rate adjusting means.
  • the second flow rate sensor FM2 is a device that detects the drainage flow rate of the remaining portion W32 of the concentrated water W3 flowing through the drainage line L5 as the second detected flow rate value.
  • the second flow sensor FM2 is electrically connected to the control unit 30.
  • the second detected flow rate value of the remaining portion W32 of the concentrated water W3 detected by the second flow rate sensor FM2 is transmitted to the control unit 30 as a pulse signal.
  • a pulse transmission type flow rate sensor in which an axial flow impeller or a tangential impeller (not shown) is disposed in the flow path housing can be used.
  • the drainage proportional control valve 8 is a valve capable of adjusting the drainage flow rate of the remaining portion W32 of the concentrated water W3 discharged from the drainage line L5 to the outside of the apparatus.
  • the drainage proportional control valve 8 is disposed downstream of the second flow rate sensor FM2 in the drainage line L5.
  • the drainage proportional control valve 8 is electrically connected to the control unit 30.
  • the valve opening degree of the drainage proportional control valve 8 is controlled by a drive signal transmitted from the control unit 30. By sending a current value signal (for example, 4 to 20 mA) from the control unit 30 to the drainage proportional control valve 8 and controlling the valve opening, the drainage flow rate of the remaining portion W32 of the concentrated water W3 can be adjusted. Details of the control by the control unit 30 in the drainage proportional control valve 8 will be described later.
  • the control unit 30 is configured by a microprocessor (not shown) including a CPU and a memory. Hereinafter, functions of the control unit 30 will be described.
  • the control unit 30 can execute the water amount control of the permeated water W2.
  • a semipermeable membrane represented by an RO membrane (reverse osmosis membrane) has a water permeability coefficient that varies depending on the temperature of raw water and the state of the membrane (blockage of pores and oxidative deterioration of material). Therefore, in the reverse osmosis membrane separation device 1, the water amount control of the permeate water W2 is performed in order to keep the flow rate of the permeate always constant regardless of the temperature of the raw water and the state of the membrane.
  • the control unit 30 can select and execute, for example, flow rate feedback water amount control, pressure feedback water amount control, or temperature feedforward water amount control as the water amount control of the permeated water W2.
  • the outline of each water quantity control is as follows.
  • the flow rate feedback water amount control control unit 30 controls the drive of the pressure pump 2.
  • the control unit 30 controls the first detected flow rate value (in-system) of the first flow rate sensor FM1 so that the first detected flow rate value of the permeated water W2 detected by the first flow rate sensor FM1 becomes a preset target flow rate value.
  • the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “flow rate feedback water amount control”).
  • a speed type digital PID algorithm can be used for calculation of the drive frequency in the main water amount control.
  • the pressure feedback water amount control control unit 30 detects the detected discharge pressure value (physical amount in the system) of the discharge pressure sensor PS3 so that the flow rate of the permeated water W2 becomes a preset target flow rate value. Is used as a feedback value to calculate the driving frequency of the pressurizing pump 2. Then, the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “pressure feedback water amount control”). For example, a speed type digital PID algorithm can be used for calculation of the drive frequency in the main water amount control.
  • the detected discharge pressure of the discharge pressure sensor PS3 is used instead of the flow rate feedback water amount control executed using the first detected flow value of the first flow sensor FM1.
  • Pressure feedback water volume control performed using the values can be performed as a backup.
  • the present embodiment includes a discharge pressure sensor PS3 that acquires the discharge pressure value (operating pressure value) of the pressurizing pump 2 in preparation for backup.
  • the temperature feedforward water amount control control unit 30 detects a temperature value (not shown) detected by a temperature sensor (not shown) of the raw water W1 so that the flow rate of the permeated water W2 becomes a preset target flow rate value.
  • the driving frequency of the pressurizing pump 2 is calculated using the physical quantity in the system as a feedforward value.
  • the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “temperature feedforward water amount control”).
  • the circulation ratio of the concentrated water W3 is the ratio between the flow rate of the permeated water W2 flowing out from the secondary side port of the RO membrane module 4 and the flow rate of the concentrated water W3 flowing out from the primary side outlet port. (Flow rate of concentrated water W3 / flow rate of permeated water W2).
  • the predetermined value of the circulation ratio is about “5”.
  • the constant flow valve 5 is provided in the concentrated water line L3. Therefore, the circulation ratio of the concentrated water W3 is set to a predetermined value by holding the flow rate of the permeated water W2 constant by any of the above-described water amount control while holding the flow rate of the concentrated water W3 constant by the constant flow valve 5. Will be adjusted to.
  • the recovery rate of the permeated water W2 is a ratio of the flow rate of the permeated water W2 to the flow rate of the raw water W1 supplied to the RO membrane module 4 (flow rate of the permeated water W2 / flow rate of the raw water W1).
  • Permeate W2 recovery rate control adjusts the recovery rate of permeate W2 to maintain the water permeability of the RO membrane module 4 to prevent scale deposition and fouling on the membrane surface. It is control to drive while.
  • the control unit 30 can select and execute, for example, temperature feedforward recovery rate control, water quality feedforward control, or water quality feedback recovery rate control as the recovery rate control of the permeated water W2.
  • the outline of each recovery rate control is as follows.
  • the temperature feedforward recovery rate control control unit 30 allows permissible concentration of silica in the concentrated water W3 based on the silica concentration determined from the silica concentration of the raw water W1 acquired in advance and the detected temperature value of a temperature sensor (not shown). Calculate the magnification. Then, the control unit 30 calculates the drainage flow rate from the calculated value of the allowable concentration magnification and the target flow rate value of the permeated water W2, and the actual drainage flow rate of the concentrated water W3 (the second detected flow rate value of the second flow rate sensor FM2) is obtained.
  • the valve opening degree of the drainage proportional control valve 8 is controlled so as to be a calculated value of the drainage flow rate (target drainage flow rate) (hereinafter also referred to as “temperature feedforward recovery rate control”).
  • the silica membrane scale deposition in the RO membrane module 4 is more reliably performed while maximizing the recovery rate of the permeate W2. Can be suppressed.
  • the water quality feedforward recovery rate control control unit 30 calculates the allowable concentration rate of calcium carbonate in the concentrated water W3 based on the previously obtained solubility of calcium carbonate and the measured hardness value of a hardness sensor (not shown). Then, the control unit 30 calculates the drainage flow rate from the calculated value of the allowable concentration magnification and the target flow rate value of the permeated water W2, and the actual drainage amount of the concentrated water W3 (the second detected flow rate value of the second flow rate sensor FM2) is drained.
  • the valve opening degree of the drainage proportional control valve 8 is controlled so as to be the calculated value of the flow rate (target drainage flow rate) (hereinafter also referred to as “water quality feedforward recovery rate control”).
  • the control unit 30 When the water quality feedforward recovery rate control is executed, the control unit 30 reverses even if the amount of hardness leak from the preceding water softening device is increased if a water softening device (not shown) is disposed in the previous stage. In the osmosis membrane separator 1, precipitation of calcium carbonate scale in the RO membrane module 4 can be more reliably suppressed while maximizing the recovery rate of the permeated water W2.
  • the water quality feedback recovery rate control control unit 30 directly controls the valve opening degree of the drainage proportional control valve 8 so that the measured electrical conductivity value of the permeated water W2 becomes a preset target electrical conductivity (hereinafter, referred to as “the measured electrical conductivity value”). Also called “water quality feedback recovery rate control”). For example, a speed type digital PID algorithm can be used to determine the valve opening in this control. Since the control unit 30 performs water quality feedback recovery rate control, the reverse osmosis membrane separation device 1 can increase the recovery rate of the permeated water W2 to the maximum while satisfying the water quality required for the permeated water W2. it can.
  • ⁇ Drainage flow rate adjustment control using drainage proportional control valve 8> This adjustment control is executed in association with the temperature feedforward recovery rate control or the water quality feedforward recovery rate control in the recovery rate control described above.
  • the control unit 30 drainage control unit
  • the control unit 30 is configured to adjust the drainage flow rate so that the second detected flow rate value of the second flow rate sensor FM2 becomes the calculated value (target drainage flow rate) of the drainage flow rate determined by the recovery rate control described above.
  • the flow rate feedback control of the valve opening degree of the drainage proportional control valve 8 is performed. For example, a speed type digital PID algorithm can be used for the calculation of the valve opening degree in this adjustment control.
  • the water amount control and the recovery rate control of the permeated water W2 are executed in combination.
  • a first control pattern that is executed in combination with “flow rate feedback water amount control” and “temperature feedforward recovery rate control”, or a combination of “pressure feedback water amount control” and “water quality feedforward recovery rate control” The second control pattern to be executed and the third control pattern executed in combination with “temperature feedforward water amount control” and “water quality feedback recovery rate control” are exemplified. In the present invention, combinations other than the first to third control patterns are not excluded.
  • the temperature feedforward recovery rate control is executed in parallel with the flow rate feedback water amount control.
  • the temperature feedforward recovery rate control is executed in parallel with the pressure feedback water amount control.
  • the water quality feedback recovery rate control is executed in parallel with the temperature feedforward water amount control.
  • the raw water pressure of the raw water W1 is reduced to a predetermined constant pressure value by using a pressure reducing valve (not shown) that reduces the raw water pressure of the raw water W1 flowing through the raw water line L1 to a predetermined constant pressure value.
  • a pressure reducing valve (not shown) that reduces the raw water pressure of the raw water W1 flowing through the raw water line L1 to a predetermined constant pressure value.
  • the discharge pressure of the pressurizing pump 2 (the operating pressure of the pressurizing pump 2, the input pressure to the primary side inlet port of the RO membrane module 4) is controlled to be high.
  • the raw water pressure of the raw water reduced by a pressure reducing valve (not shown) is adjusted to a predetermined constant pressure value regardless of the water temperature of the raw water W1.
  • the pressure on the primary side of the constant flow valve 5 is sufficiently higher than the pressure on the secondary side of the constant flow valve 5 compared to the case where the temperature of the raw water W1 is high. Get higher. Further, the pressure on the secondary side of the constant flow valve 5 is low because the raw water pressure is reduced. Thereby, when the temperature of the raw water W1 is low, the constant flow valve differential pressure on the primary side and the secondary side of the constant flow valve 5 is larger than the predetermined differential pressure when compared with the case where the temperature of the raw water W1 is high. It is secured with a margin.
  • the constant flow valve differential pressure can be sufficiently secured, but on the upstream side of the pressurizing pump 2,
  • the raw water pressure of the raw water W1 is reduced by a pressure reducing valve (not shown) to the same predetermined constant pressure value as when the temperature of the raw water W1 is high.
  • the raw water decompressed by the pressure reducing valve (not shown) is pressurized by the pressurizing pump 2.
  • the raw water W1 is low and the raw water pressure of the raw water W1 can be effectively used while being high in order to distribute the raw water W1 toward the RO membrane module 4 while ensuring the constant flow valve differential pressure, the raw water W1.
  • the power consumption of the pressurizing pump 2 that pumps the raw water pressure can be reduced.
  • the control unit 30 calculates (detects) the detected differential pressure value so that the pressure of the raw water W1 increases within a range where the detected differential pressure value is equal to or greater than a predetermined set differential pressure value.
  • control is performed so as to adjust the valve opening degree (flow passage cross-sectional area) of the raw water proportional control valve 14.
  • the detected differential pressure value is a differential pressure between the primary side pressure and the secondary side pressure of the constant flow valve 5 (the constant flow valve differential pressure).
  • the detected differential pressure value is calculated based on the detected secondary pressure value detected by the secondary pressure sensor PS2 and the detected primary pressure value detected by the primary pressure sensor PS1.
  • the control part 30 is the valve opening degree (flow path) of the raw
  • the set differential pressure value is a differential pressure value obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5.
  • a lower limit value at which the concentrated water W3 can flow from the primary side to the secondary side of the constant flow valve 5 is set.
  • the set differential pressure value is set to 0.2 Mpa, for example.
  • a speed type digital PID algorithm can be used for calculation of the valve opening degree in the adjustment control.
  • FIG. 2 is a flowchart showing a processing procedure when adjusting the differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5 by controlling the raw water proportional control valve 14 in the control unit 30. .
  • the process of the flowchart shown in FIG. 2 is repeatedly performed during the operation of the reverse osmosis membrane separation device 1.
  • the raw water pump 12 is controlled to discharge the raw water W1 at a predetermined pressure value (for example, 0.3 MPa).
  • a predetermined pressure value for example, 0.3 MPa.
  • the valve opening degree of the raw water proportional control valve 14 is set to fully open (valve opening degree 100%).
  • the flow passage cross-sectional area of the raw water proportional control valve 14 is smaller than the flow path upstream of the raw water proportional control valve 14.
  • the raw water pressure of the raw water W1 flowing through the raw water line L1 may decrease after passing through the raw water proportional control valve 14. Therefore, the discharge pressure of the raw water pump 12 may be set in anticipation of a decrease in the raw water pressure in the raw water proportional control valve 14.
  • the pressure value of the raw water pressure downstream of the raw water proportional control valve 14 at the time of startup is the valve opening of the raw water proportional control valve 14. The pressure value does not decrease from when fully open.
  • the raw water W1 is circulated toward the pressurizing pump 2 at a pressure value that does not decrease the raw water pressure of the raw water W1 from the case where the opening degree of the raw water proportional control valve 14 is fully open.
  • step S1 the control unit 30 performs flow rate feedback water amount control, pressure feedback water amount control, or temperature feedforward water amount control as described above, for example, as the water amount control of the permeated water W2.
  • step S2 the control unit 30 executes recovery rate control that is executed in parallel with the water amount control of the permeated water W2.
  • the control unit 30 performs temperature feedforward recovery rate control, water quality feedforward control, or water quality feedback recovery rate control as the recovery rate control of the permeated water W2.
  • step S3 the control unit 30 acquires the detected secondary pressure value on the secondary side of the constant flow valve 5 detected by the secondary pressure sensor PS2.
  • step S4 the control unit 30 acquires the detected primary pressure value on the primary side of the constant flow valve 5 detected by the primary pressure sensor PS1.
  • step S5 the control unit 30 calculates (detects) the detected differential pressure value based on the detected secondary pressure value acquired in step S3 and the detected primary pressure value acquired in step S4.
  • the detected differential pressure value is a differential pressure value obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5.
  • step S6 the control unit 30 controls the raw water proportional control so that the pressure of the raw water W1 increases in a range where the detected differential pressure value calculated in step S5 is equal to or higher than a predetermined set differential pressure value (for example, 0.2 MPa). Control is performed so as to adjust the valve opening (flow passage cross-sectional area) of the valve 14. Accordingly, the raw water pressure of the raw water W1 can be increased on the downstream side of the raw water proportional control valve 14 while ensuring the differential pressure between the primary pressure and the secondary pressure of the constant flow valve 5. Therefore, the pressure of the raw water W1 can be used effectively.
  • step S6 the process of this flowchart ends (returns to step S1).
  • the RO membrane module 4 the raw water line L1, the permeate water line L2, the concentrated water line L3, and the concentrated water line L3 are branched and separated by the RO membrane module 4.
  • a part of the concentrated water W3 W31 is returned to the merging portion J2 of the raw water line L1, a circulating water line L4, a drain line L5 branched from the concentrated water line L3, and a raw water line L1 upstream from the merging portion J2.
  • the raw water proportional control valve 14 for adjusting the pressure of the raw water W1 that flows through the water, the constant flow valve 5 that maintains the flow rate of the concentrated water W3 that flows through the concentrated water line L3 at a predetermined constant flow value, and the primary of the constant flow valve 5 Primary side pressure sensor PS1, secondary side pressure sensor PS2, and control unit 30 for detecting the differential pressure between the primary side pressure and the secondary side pressure as the detected differential pressure value, and the detected differential pressure value is greater than or equal to a predetermined set differential pressure Range As the pressure of the raw water is high, and a control unit 30 for controlling the raw water proportional control valve 14, the.
  • the constant flow valve differential pressure can be adjusted so that the concentrated water W 3 flows from the primary side to the secondary side of the constant flow valve 5. .
  • the raw water pressure of the raw water W1 can be effectively used to reduce the load of the pressurizing pump 2 and reduce the discharge pressure of the pressurizing pump 2. Therefore, the power consumption of the pressurizing pump 2 can be reduced.
  • the opening degree of the raw water proportional control valve 14 is increased as the temperature of the raw water W1 decreases, it is not necessary to reduce the raw water pressure of the raw water W1 using a pressure reducing valve or the like.
  • the control unit 30 controls the flow rate of the permeate W2 by flow rate feedback water amount control.
  • the first detected flow rate is obtained by calculating a change from the previous manipulated variable and adding the previous manipulated variable to this to obtain the present manipulated variable. Even when the value is a discrete value, the deviation from the target flow rate value can be eliminated at high speed. Therefore, even when the water permeation coefficient of the RO membrane module 4 changes abruptly due to temperature change, membrane clogging, or the like, the change can be sufficiently followed.
  • the flow rate of the permeate water W2 can be converged to the target flow rate value in a short time, and the permeate water W2 having a stable water amount can be manufactured.
  • the control unit 30 controls the flow rate of the permeated water W2 by pressure feedback water amount control.
  • This pressure feedback water amount control can be executed as a backup of the flow rate feedback water amount control. Therefore, even when a failure occurs in the first flow sensor FM1 (see FIG. 1) during the flow rate feedback water amount control, the permeated water W4 having a stable water amount is manufactured by switching to the pressure feedback water amount control. Can do.
  • the control unit 30 controls the flow rate of the permeated water W2 by temperature feedforward water amount control.
  • This temperature feedforward water amount control can be executed as a backup of the flow rate feedback water amount control in the first embodiment. Therefore, even when a failure occurs in the first flow sensor FM1 (see FIG. 1) during the execution of the flow rate feedback water amount control, the permeated water W2 having a stable water amount is manufactured by switching to the temperature feedforward water amount control. be able to.
  • control unit 30 executes temperature feedforward recovery rate control. For this reason, in the reverse osmosis membrane separation apparatus 1, precipitation of the silica scale in the RO membrane module 4 can be more reliably suppressed while maximizing the recovery rate of the permeated water W2.
  • the control unit 30 executes water quality feedforward recovery rate control. For this reason, for example, even when the amount of hardness leak from the previous water softening device increases, the reverse osmosis membrane separation device 1 maximizes the recovery rate of the permeated water W2, and the calcium carbonate scale in the RO membrane module 4 Can be more reliably suppressed.
  • the control unit 30 executes water quality feedback recovery rate control. For this reason, in the reverse osmosis membrane separation apparatus 1, the recovery rate of the permeated water W2 can be maximized while satisfying the water quality required for the permeated water W2.
  • the present invention is not limited to the above-described embodiments, and can be implemented in various forms.
  • the example in which the drainage flow rate of the concentrated water W3 is adjusted by controlling the valve opening degree of the drainage proportional control valve 8 in each recovery rate control has been described.
  • a configuration in which a plurality of drain valves are provided in parallel, and the drain flow rate of the remaining portion W32 of the concentrated water W3 can be controlled in stages by increasing or decreasing the number of drain valves opened. Good. Thereby, the waste_water

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Abstract

A reverse osmosis membrane separation apparatus provided with: a reverse osmosis membrane module (4); a raw water line (L1); a permeate line (L2); a concentrate line (L3); a circulating water line (L4) for returning a portion (W31) of the concentrate (W3) to a merging part (J2) of the raw water line (L1); a waste water line (L5); a raw water pressure-adjusting means (14) for adjusting the pressure of raw water (W1) upstream of the merging part (J2); a steady flow means (5) for keeping the flow of the concentrate (W3) at a specified constant flow; steady flow differential pressure-detecting means (PS1), (PS2), (30) for detecting the differential pressure between the first-side pressure and the second-side pressure of the constant flow means (5) as a detected differential pressure value; and a raw water pressure controlling unit (30) for controlling the raw water pressure-adjusting means (14) so that the pressure of the raw water increases in a range in which the detected differential pressure value is at least a specified set differential pressure.

Description

逆浸透膜分離装置Reverse osmosis membrane separator
　本発明は、逆浸透膜モジュールを備える逆浸透膜分離装置に関する。本願は、２０１６年６月１３日に日本に出願された特願２０１６－１１７３８１号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a reverse osmosis membrane separation device including a reverse osmosis membrane module. This application claims priority based on Japanese Patent Application No. 2016-117381 for which it applied to Japan on June 13, 2016, and uses the content here.
　半導体の製造工程、電子部品や医療器具の洗浄等においては、不純物を含まない高純度の純水が使用される。この種の純水は、一般に、地下水や水道水等の原水を、逆浸透膜モジュール（以下、「ＲＯ膜モジュール」ともいう）で逆浸透膜分離処理することにより製造される。 High purity pure water that does not contain impurities is used in semiconductor manufacturing processes, cleaning of electronic parts and medical equipment, and the like. This type of pure water is generally produced by subjecting raw water such as groundwater or tap water to a reverse osmosis membrane separation treatment with a reverse osmosis membrane module (hereinafter also referred to as “RO membrane module”).
　高分子材料からなる逆浸透膜の水透過係数は、温度により変化する。また、逆浸透膜の水透過係数は、細孔の閉塞（以下、「膜閉塞」ともいう）や、材質の酸化による劣化（以下、「膜劣化」ともいう）によっても変化する。 The water permeability coefficient of a reverse osmosis membrane made of a polymer material varies depending on the temperature. Further, the water permeation coefficient of the reverse osmosis membrane also changes due to pore clogging (hereinafter also referred to as “membrane clogging”) and deterioration due to oxidation of the material (hereinafter also referred to as “membrane degradation”).
　そこで、原水の温度や逆浸透膜の状態にかかわらず、ＲＯ膜モジュールにおける透過水の流量を一定に保つため、流量フィードバック水量制御を行う水質改質システムが提案されている（例えば、特許文献１参照）。この流量フィードバック水量制御では、ＲＯ膜モジュールで製造される透過水の流量が目標流量値となるように、加圧ポンプの駆動周波数がインバータにより制御される。 Therefore, a water quality reforming system that performs flow rate feedback water volume control in order to keep the flow rate of the permeated water in the RO membrane module constant regardless of the temperature of the raw water and the state of the reverse osmosis membrane has been proposed (for example, Patent Document 1). reference). In this flow rate feedback water amount control, the drive frequency of the pressure pump is controlled by the inverter so that the flow rate of the permeated water produced by the RO membrane module becomes the target flow rate value.
　流量フィードバック水量制御を行うシステムにおいては、水温が高い場合には、水の粘性が小さく、ＲＯ膜モジュールの水透過係数が高くなるため、加圧ポンプの吐出圧力（加圧ポンプの運転圧力、ＲＯ膜モジュールの一次側入口ポートへの入力圧力）が低くなるように制御される。また、水温が低い場合には、水の粘性が大きく、ＲＯ膜モジュールの水透過係数が低くなるため、加圧ポンプの吐出圧力（加圧ポンプの運転圧力、ＲＯ膜モジュールの一次側入口ポートへの入力圧力）が高くなるように制御される。 In a system that performs flow rate feedback water volume control, when the water temperature is high, the viscosity of the water is small and the water permeability coefficient of the RO membrane module is high, so that the discharge pressure of the pressurizing pump (operating pressure of the pressurizing pump, RO The input pressure to the primary inlet port of the membrane module is controlled to be low. Also, when the water temperature is low, the viscosity of the water is large and the water permeability coefficient of the RO membrane module is low, so the discharge pressure of the pressurizing pump (the operating pressure of the pressurizing pump, to the primary side inlet port of the RO membrane module) The input pressure is controlled to be high.
　上記水質改質システムにおいて、ＲＯ膜モジュールで分離された濃縮水は、ＲＯ膜モジュールの一次側出口ポートに接続された濃縮水ラインから送出される。また、ＲＯ膜モジュールで分離された透過水は、ＲＯ膜モジュールの二次側ポートに接続された透過水ラインから送出される。濃縮水ラインは、循環水ラインと濃縮水排水ラインとに分岐している。循環水ラインは、濃縮水ラインから送出された濃縮水の一部を、加圧ポンプの上流側における原水ラインの合流部に返送するラインである。濃縮水排水ラインは、濃縮水ラインから送出された濃縮水の残部を装置外に排出するラインである。原水ラインは、加圧ポンプを介してＲＯ膜モジュールに原水を供給するラインである。 In the water quality reforming system, the concentrated water separated by the RO membrane module is sent out from the concentrated water line connected to the primary outlet port of the RO membrane module. Moreover, the permeated water separated by the RO membrane module is sent out from the permeated water line connected to the secondary side port of the RO membrane module. The concentrated water line is branched into a circulating water line and a concentrated water drainage line. The circulating water line is a line that returns a part of the concentrated water sent from the concentrated water line to the merging portion of the raw water line on the upstream side of the pressurizing pump. The concentrated water drainage line is a line for discharging the remaining portion of the concentrated water sent from the concentrated water line to the outside of the apparatus. The raw water line is a line for supplying raw water to the RO membrane module via a pressure pump.
　ここで、特許文献１に記載の濃縮水が流通する流路構成を有する技術において、濃縮水ラインを流れる濃縮水の流量を一定に保つために、濃縮水ラインに定流量弁を設ける技術が知られている（例えば、特許文献２参照）。特許文献２に記載の技術においては、定流量弁を通過した濃縮水の一部は、循環水ラインを流通して、原水ラインの合流部に返送される。 Here, in the technology having the flow path configuration through which the concentrated water flows as described in Patent Document 1, a technology for providing a constant flow valve in the concentrated water line is known in order to keep the flow rate of the concentrated water flowing through the concentrated water line constant. (For example, refer to Patent Document 2). In the technique described in Patent Document 2, a portion of the concentrated water that has passed through the constant flow valve flows through the circulating water line and is returned to the confluence portion of the raw water line.
　特許文献２に記載の濃縮水ラインに定流量弁が設けられる技術においては、定流量弁の二次側の圧力が原水ラインの原水圧力となっている。そのため、原水の原水圧力が高い場合には、濃縮水ラインに設けられる定流量弁の一次側と二次側との圧力差が小さくなり、一次側圧力から二次側圧力を減じた差圧を確保できずに、濃縮水の一部を、循環水ラインを介して原水ラインの合流部に返送できないことになる。 In the technology in which a constant flow valve is provided in the concentrated water line described in Patent Document 2, the pressure on the secondary side of the constant flow valve is the raw water pressure of the raw water line. Therefore, when the raw water raw water pressure is high, the pressure difference between the primary side and secondary side of the constant flow valve provided in the concentrated water line becomes small, and the differential pressure obtained by subtracting the secondary side pressure from the primary side pressure is reduced. It cannot be ensured, and part of the concentrated water cannot be returned to the confluence of the raw water line via the circulating water line.
　これに対して、原水ラインを流通する原水の原水圧力を所定の一定圧力値に減圧する減圧弁を用いて、原水の原水圧力を所定の一定圧力値まで減圧して、定流量弁の二次側の圧力を下げることで、定流量弁の一次側と二次側とにおいて、一次側圧力から二次側圧力を減じた差圧が所定差圧以上になるように調整する技術がある。 In contrast, using a pressure reducing valve that reduces the raw water pressure flowing through the raw water line to a predetermined constant pressure value, the raw water pressure is reduced to a predetermined constant pressure value, and the secondary flow of the constant flow valve is reduced. There is a technique of adjusting the differential pressure obtained by subtracting the secondary side pressure from the primary side pressure to be equal to or higher than a predetermined differential pressure on the primary side and secondary side of the constant flow valve by lowering the pressure on the side.
　減圧弁を用いて原水の原水圧力を所定の一定圧力値に減圧する理由は、以下の通りである。原水の温度が高い場合には、原水の温度が低い場合と比べて、水の粘性が小さく、ＲＯ膜モジュールの水透過係数が高くなるため、流量フィードバック水量制御を行うシステムにおいては、加圧ポンプの吐出圧力（加圧ポンプの運転圧力、ＲＯ膜モジュールの一次側入口ポートへの入力圧力）が低くなるように制御される。このように、原水の温度が高くなるに従って加圧ポンプの吐出圧力が低下するため、定流量弁の一次側と二次側との差圧を十分に得るためには、減圧弁を用いて、加圧ポンプの上流側の原水圧力を所定の一定圧力値に減圧する必要があった。 The reason why the raw water pressure is reduced to a predetermined constant pressure value using the pressure reducing valve is as follows. When the raw water temperature is high, the viscosity of the water is small and the water permeability coefficient of the RO membrane module is high compared to when the raw water temperature is low. The discharge pressure (operating pressure of the pressure pump, input pressure to the primary side inlet port of the RO membrane module) is controlled to be low. Thus, since the discharge pressure of the pressurizing pump decreases as the temperature of the raw water increases, in order to obtain a sufficient differential pressure between the primary side and the secondary side of the constant flow valve, a pressure reducing valve is used. It was necessary to reduce the raw water pressure upstream of the pressurizing pump to a predetermined constant pressure value.
　また、原水の温度が低い場合には、原水の温度が高い場合と比べて、水の粘性が大きく、ＲＯ膜モジュールの水透過係数が低くなるため、流量フィードバック水量制御を行うシステムにおいては、加圧ポンプの吐出圧力（加圧ポンプの運転圧力、ＲＯ膜モジュールの一次側入口ポートへの入力圧力）が高くなるように制御される。一方、原水の水温によらず、減圧弁により減圧される原水の原水圧力は、所定の一定圧力値に調整されている。そのため、原水の温度が低い場合には、原水の温度が高い場合と比べて、定流量弁の一次側の圧力は、定流量弁の二次側の圧力に対して、十分に高くなる。また、定流量弁の二次側の圧力は、原水圧力が減圧されているため、低くなる。これにより、原水の温度が低い場合には、原水の温度が高い場合と比べて、定流量弁の一次側と二次側とにおいて、一次側圧力から二次側圧力を減じた差圧は、所定差圧を大きく超えて余裕をもって確保されることになる。 In addition, when the raw water temperature is low, the viscosity of the water is larger and the water permeability coefficient of the RO membrane module is lower than when the raw water temperature is high. Control is performed so that the discharge pressure of the pressure pump (the operating pressure of the pressure pump, the input pressure to the primary inlet port of the RO membrane module) is increased. On the other hand, regardless of the raw water temperature, the raw water pressure reduced by the pressure reducing valve is adjusted to a predetermined constant pressure value. Therefore, when the temperature of the raw water is low, the pressure on the primary side of the constant flow valve is sufficiently higher than the pressure on the secondary side of the constant flow valve as compared with the case where the temperature of the raw water is high. Further, the pressure on the secondary side of the constant flow valve is low because the raw water pressure is reduced. As a result, when the raw water temperature is low, the differential pressure obtained by subtracting the secondary side pressure from the primary side pressure on the primary side and secondary side of the constant flow valve compared to when the raw water temperature is high is: The predetermined differential pressure is greatly exceeded and secured with a margin.
特開２００５－２９６９４５号公報JP 2005-296945 A 特開２０１４－２１３２６０号公報JP 2014-213260 A
　特許文献２に記載の濃縮水ラインに定流量弁が設けられる技術においては、原水の温度が低い場合に、定流量弁の一次側圧力から二次側圧力を減じた差圧を十分に確保できるにもかかわらず、加圧ポンプの上流側において、原水の原水圧力を減圧弁により、原水の温度が高い場合と同じ所定の一定圧力値に減圧することになる。一方で、減圧弁の下流側の原水ラインにおいて、減圧弁で減圧された原水を加圧ポンプにより加圧する。このように、原水の温度が低い場合において、減圧弁で一旦減圧された原水の原水圧力を加圧ポンプにおいて昇圧させる必要があった。これにより、加圧ポンプの消費電力が多くなっていた。 In the technology in which the constant flow valve is provided in the concentrated water line described in Patent Document 2, when the temperature of the raw water is low, a sufficient differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve can be secured. Nevertheless, on the upstream side of the pressurizing pump, the raw water pressure is reduced by the pressure reducing valve to the same predetermined constant pressure value as when the temperature of the raw water is high. On the other hand, in the raw water line on the downstream side of the pressure reducing valve, the raw water decompressed by the pressure reducing valve is pressurized by a pressure pump. As described above, when the temperature of the raw water is low, the raw water pressure once reduced by the pressure reducing valve needs to be increased by the pressurizing pump. Thereby, the power consumption of the pressure pump has increased.
　このため、原水の温度が低い場合に、定流量弁の一次側圧力から二次側圧力を減じた差圧を確保しつつ、ＲＯ膜モジュールに向けて流通させるために、原水の原水圧力を高いまま有効に利用できれば、原水に原水圧力を圧送する加圧ポンプの消費電力を低減できる。
　よって、定流量弁（定流量手段）の一次側圧力から二次側圧力を減じた差圧を確保しつつ、原水ラインを流通する原水の原水圧力を有効に利用することができる逆浸透膜分離装置が望まれる。 For this reason, when the temperature of the raw water is low, the raw water pressure is increased in order to circulate toward the RO membrane module while ensuring the differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve. If it can be used effectively as it is, the power consumption of the pressurizing pump that pumps the raw water pressure to the raw water can be reduced.
Therefore, reverse osmosis membrane separation that can effectively utilize the raw water pressure of raw water flowing through the raw water line while ensuring a differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve (constant flow means). An apparatus is desired.
　本発明は、逆浸透膜モジュールと、原水を逆浸透膜モジュールに供給する原水ラインと、逆浸透膜モジュールで分離された濃縮水を排出する濃縮水ラインと、濃縮水ラインから分岐され濃縮水の一部を逆浸透膜モジュールに返送する循環水ラインと、濃縮水ラインに設けられる定流量手段と、を備える逆浸透膜分離装置において、定流量手段の一次側圧力から二次側圧力を減じた差圧を確保しつつ、原水ラインを流通する原水の原水圧力を有効に利用することができる逆浸透膜分離装置を提供することを目的とする。 The present invention relates to a reverse osmosis membrane module, a raw water line for supplying raw water to the reverse osmosis membrane module, a concentrated water line for discharging concentrated water separated by the reverse osmosis membrane module, and a concentrated water branched from the concentrated water line. In a reverse osmosis membrane separation device comprising a circulating water line for returning a part to the reverse osmosis membrane module and a constant flow means provided in the concentrated water line, the secondary pressure is reduced from the primary pressure of the constant flow means. It aims at providing the reverse osmosis membrane separation apparatus which can utilize effectively the raw | natural water pressure of the raw | natural water which distribute | circulates a raw | natural water line, ensuring a differential pressure | voltage.
　本発明は、原水を透過水と濃縮水とに分離する逆浸透膜モジュールと、原水を前記逆浸透膜モジュールに供給する原水ラインと、前記逆浸透膜モジュールで分離された透過水を送出する透過水ラインと、前記逆浸透膜モジュールで分離された濃縮水を送出する濃縮水ラインと、前記濃縮水ラインから分岐され、前記逆浸透膜モジュールで分離された濃縮水の一部を前記原水ラインの合流部に返送する循環水ラインと、前記濃縮水ラインから分岐され、前記逆浸透膜モジュールで分離された濃縮水の残部を装置外へ排出する排水ラインと、前記合流部よりも上流側の前記原水ラインに設けられ、前記合流部よりも上流側の前記原水ラインを流通する原水の圧力を調整する原水圧力調整手段と、前記濃縮水ラインに設けられ、前記濃縮水ラインを流通する濃縮水の流量を所定の一定流量値に保持する定流量手段と、前記定流量手段の一次側の圧力と二次側の圧力との差圧を検出差圧値として検出する定流量差圧検出手段と、前記検出差圧値が所定の設定差圧以上になる範囲で原水の圧力が高くなるように、前記原水圧力調整手段を制御する原水圧力制御部と、を備える、逆浸透膜分離装置に関する。 The present invention includes a reverse osmosis membrane module that separates raw water into permeated water and concentrated water, a raw water line that supplies raw water to the reverse osmosis membrane module, and a permeate that delivers permeated water separated by the reverse osmosis membrane module. A water line, a concentrated water line for sending concentrated water separated by the reverse osmosis membrane module, and a part of the concentrated water branched from the concentrated water line and separated by the reverse osmosis membrane module in the raw water line A circulating water line to be returned to the merging section, a drainage line that is branched from the concentrated water line and separated by the reverse osmosis membrane module, and discharges the remaining concentrated water to the outside of the apparatus, and the upstream side of the merging section A raw water pressure adjusting means for adjusting a pressure of the raw water flowing through the raw water line upstream of the confluence portion, provided in the raw water line, and provided in the concentrated water line; Constant flow rate means for maintaining the flow rate of circulating concentrated water at a predetermined constant flow value, and a constant flow rate difference for detecting a differential pressure between a primary pressure and a secondary pressure of the constant flow rate means as a detected differential pressure value A reverse osmosis membrane, comprising: a pressure detection unit; and a raw water pressure control unit that controls the raw water pressure adjustment unit so that the pressure of the raw water is increased in a range where the detected differential pressure value is equal to or larger than a predetermined set differential pressure. The present invention relates to a separation device.
　また、前記合流部よりも下流側の前記原水ラインに設けられ、原水を吸入して前記逆浸透膜モジュールに向けて吐出する加圧ポンプと、透過水の流量を第１検出流量値として検出する第１流量検出手段と、前記第１検出流量値が予め設定された目標流量値となるように、前記加圧ポンプの駆動を制御する加圧ポンプ駆動制御部と、を備えることが好ましい。 A pressure pump provided in the raw water line downstream of the junction and sucking the raw water and discharging the raw water toward the reverse osmosis membrane module; and detecting a flow rate of the permeated water as a first detected flow rate value. It is preferable to include a first flow rate detection unit and a pressurization pump drive control unit that controls driving of the pressurization pump so that the first detection flow rate value becomes a preset target flow rate value.
　また、前記排水ラインに設けられ、装置外へ排出する濃縮水の排水流量を調整可能な排水流量調整手段と、原水、透過水又は濃縮水の温度を検出温度値として検出する温度検出手段と、前記排水流量調整手段を制御する排水制御部と、を備え、前記排水制御部は、（ｉ）予め取得された原水のシリカ濃度、及び前記温度検出手段の検出温度値から決定したシリカ溶解度に基づいて、濃縮水におけるシリカの許容濃縮倍率を演算し、（ｉｉ）当該許容濃縮倍率の演算値、及び透過水の前記目標流量値から排水流量を演算し、（ｉｉｉ）濃縮水の実際排水流量が当該排水流量の演算値となるように、前記排水流量調整手段を制御することが好ましい。 Also, a drainage flow rate adjusting means provided in the drainage line and capable of adjusting the drainage flow rate of the concentrated water discharged outside the apparatus, and a temperature detection means for detecting the temperature of the raw water, the permeated water or the concentrated water as a detected temperature value, A drainage control unit that controls the drainage flow rate adjusting means, and the drainage control unit is based on (i) the silica concentration determined from the silica concentration of raw water obtained in advance and the detected temperature value of the temperature detecting means. Calculating the allowable concentration rate of silica in the concentrated water, (ii) calculating the drainage flow rate from the calculated value of the allowable concentration rate and the target flow rate value of the permeate, and (iii) the actual drainage flow rate of the concentrated water is It is preferable to control the drainage flow rate adjusting means so as to obtain a calculated value of the drainage flow rate.
　また、濃縮水の排水流量を第２検出流量値として検出する第２流量検出手段を備え、前記排水流量調整手段は比例制御弁からなり、前記排水制御部は、前記第２検出流量値が前記排水流量の演算値となるように、前記比例制御弁の弁開度を調節することが好ましい。 The drainage flow rate adjusting means includes a proportional control valve that detects the drainage flow rate of the concentrated water as a second detected flow rate value, and the drainage control unit is configured such that the second detected flow rate value is It is preferable to adjust the valve opening degree of the proportional control valve so that the drainage flow rate is calculated.
　本発明によれば、逆浸透膜モジュールと、原水を逆浸透膜モジュールに供給する原水ラインと、逆浸透膜モジュールで分離された濃縮水を排出する濃縮水ラインと、濃縮水ラインから分岐され濃縮水の一部を逆浸透膜モジュールに返送する循環水ラインと、濃縮水ラインに設けられる定流量手段と、を備える逆浸透膜分離装置において、定流量手段の一次側圧力から二次側圧力を減じた差圧を確保しつつ、原水ラインを流通する原水の原水圧力を有効に利用することができる逆浸透膜分離装置を提供することができる。 According to the present invention, a reverse osmosis membrane module, a raw water line for supplying raw water to the reverse osmosis membrane module, a concentrated water line for discharging concentrated water separated by the reverse osmosis membrane module, and a branching and concentration from the concentrated water line In a reverse osmosis membrane separation device comprising a circulating water line for returning a part of water to the reverse osmosis membrane module, and a constant flow means provided in the concentrated water line, the secondary pressure is changed from the primary pressure of the constant flow means to the secondary osmosis membrane separation device. It is possible to provide a reverse osmosis membrane separation device that can effectively use the raw water pressure of raw water flowing through the raw water line while ensuring a reduced differential pressure.
一実施形態に係る逆浸透膜分離装置１の全体構成図である。1 is an overall configuration diagram of a reverse osmosis membrane separation device 1 according to an embodiment. 制御部３０において原水比例制御弁１４を制御することで定流量弁５の一次側の圧力から二次側の圧力を減じた差圧を調整する場合の処理手順を示すフローチャートである。4 is a flowchart showing a processing procedure in the case where a differential pressure obtained by subtracting a secondary pressure from a primary pressure of the constant flow valve 5 is adjusted by controlling the raw water proportional control valve 14 in the control unit 30.
　本発明の一実施形態に係る逆浸透膜分離装置１について、図面を参照しながら説明する。図１は、一実施形態に係る逆浸透膜分離装置１の全体構成図である。本実施形態に係る逆浸透膜分離装置１は、例えば、淡水から純水を製造する純水製造システムに適用される。 A reverse osmosis membrane separation device 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a reverse osmosis membrane separation device 1 according to an embodiment. The reverse osmosis membrane separation device 1 according to the present embodiment is applied to, for example, a pure water production system that produces pure water from fresh water.
　図１に示すように、本実施形態に係る逆浸透膜分離装置１は、原水ポンプ１２と、原水側インバータ１３と、原水圧力調整手段としての原水比例制御弁１４と、加圧ポンプ２と、加圧側インバータ３と、逆浸透膜モジュールとしてのＲＯ膜モジュール４と、定流量手段としての定流量弁５と、逆止弁６と、排水流量調整手段としての排水比例制御弁８（比例制御弁）と、流路切換弁１５と、制御部３０と、を備える。また、逆浸透膜分離装置１は、定流量差圧検出手段としての二次側圧力センサＰＳ２と、定流量差圧検出手段としての一次側圧力センサＰＳ１と、吐出圧力センサＰＳ３と、第１流量検出手段としての第１流量センサＦＭ１と、第２流量検出手段としての第２流量センサＦＭ２と、を備える。なお、制御部３０と被制御対象機器との電気的接続線の図示については、省略している。 As shown in FIG. 1, the reverse osmosis membrane separation device 1 according to the present embodiment includes a raw water pump 12, a raw water side inverter 13, a raw water proportional control valve 14 as a raw water pressure adjusting means, a pressurizing pump 2, Pressurizing side inverter 3, RO membrane module 4 as reverse osmosis membrane module, constant flow valve 5 as constant flow means, check valve 6, and drain proportional control valve 8 (proportional control valve) as drain flow rate adjusting means ), A flow path switching valve 15, and a control unit 30. The reverse osmosis membrane separation device 1 includes a secondary pressure sensor PS2 as a constant flow rate differential pressure detection unit, a primary pressure sensor PS1 as a constant flow rate differential pressure detection unit, a discharge pressure sensor PS3, and a first flow rate. A first flow rate sensor FM1 as detection means and a second flow rate sensor FM2 as second flow rate detection means are provided. Note that illustration of electrical connection lines between the control unit 30 and the controlled device is omitted.
　また、逆浸透膜分離装置１は、原水ラインＬ１と、透過水ラインＬ２と、濃縮水ラインＬ３と、循環水ラインＬ４と、排水ラインＬ５と、透過水リターンラインＬ６と、を備える。本明細書における「ライン」とは、流路、経路、管路等の流体の流通が可能なラインの総称である。 Further, the reverse osmosis membrane separation apparatus 1 includes a raw water line L1, a permeate water line L2, a concentrated water line L3, a circulating water line L4, a drainage line L5, and a permeate return line L6. 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.
　原水ラインＬ１は、原水Ｗ１をＲＯ膜モジュール４に供給するラインである。原水ラインＬ１の上流側の端部は、原水Ｗ１の供給源（不図示）に接続されている。原水ラインＬ１の下流側の端部は、ＲＯ膜モジュール４の一次側入口ポートに接続されている。原水ラインＬ１には、上流側から下流側に向けて順に、原水ポンプ１２、原水比例制御弁１４、二次側圧力センサＰＳ２、合流部Ｊ２、加圧ポンプ２、吐出圧力センサＰＳ３、ＲＯ膜モジュール４が設けられている。
　なお、原水ラインＬ１を流通する原水Ｗ１には、原水Ｗ１の供給源（不図示）から直接供給される原水に限らず、例えば、原水Ｗ１を濾過処理装置（除鉄除マンガン装置、活性炭濾過装置など）、硬水軟化装置等の前処理装置により前処理された原水も含まれる。 The raw water line L1 is a line for supplying the raw water W1 to the RO membrane module 4. The upstream end of the raw water line L1 is connected to a supply source (not shown) of the raw water W1. The downstream end of the raw water line L <b> 1 is connected to the primary inlet port of the RO membrane module 4. In the raw water line L1, in order from the upstream side to the downstream side, the raw water pump 12, the raw water proportional control valve 14, the secondary pressure sensor PS2, the merging section J2, the pressurizing pump 2, the discharge pressure sensor PS3, and the RO membrane module 4 is provided.
The raw water W1 flowing through the raw water line L1 is not limited to the raw water directly supplied from the raw water W1 supply source (not shown), but, for example, the raw water W1 is filtered by a filtration device (iron removal manganese removal device, activated carbon filtration device). Etc.), and raw water pretreated by a pretreatment device such as a water softening device is also included.
　原水ポンプ１２は、原水ラインＬ１を流通する原水Ｗ１を吸入し、加圧ポンプ２へ向けて圧送（吐出）する装置である。原水ポンプ１２には、原水側インバータ１３から周波数が変換された駆動電力が供給される。原水ポンプ１２は、供給（入力）された駆動電力の周波数（以下、「駆動周波数」ともいう）に応じた回転速度で駆動される。 The raw water pump 12 is a device that sucks the raw water W1 flowing through the raw water line L1 and pumps (discharges) the raw water W1 toward the pressurizing pump 2. The raw water pump 12 is supplied with driving power whose frequency is converted from the raw water side inverter 13. The raw water pump 12 is driven at a rotational speed corresponding to the frequency (hereinafter also referred to as “drive frequency”) of the supplied drive power (input).
　原水側インバータ１３は、原水ポンプ１２に、周波数が変換された駆動電力を供給する電気回路（又はその回路を持つ装置）である。原水側インバータ１３は、制御部３０と電気的に接続されている。原水側インバータ１３には、制御部３０から指令信号が入力される。原水側インバータ１３は、制御部３０により入力された指令信号（電流値信号又は電圧値信号）に対応する駆動周波数の駆動電力を原水ポンプ１２に出力する。 The raw water side inverter 13 is an electric circuit (or a device having the circuit) for supplying the raw water pump 12 with driving power whose frequency has been converted. The raw water side inverter 13 is electrically connected to the control unit 30. A command signal is input from the control unit 30 to the raw water side inverter 13. The raw water side inverter 13 outputs driving power having a driving frequency corresponding to the command signal (current value signal or voltage value signal) input by the control unit 30 to the raw water pump 12.
　本実施形態においては、制御部３０は、原水ポンプ１２が原水Ｗ１を所定の一定圧力値で吐出するように、原水側インバータ１３を制御する。原水ポンプ１２により付与される原水Ｗ１の前記一定圧力値は、原水ラインＬ１を流通する原水Ｗ１を加圧ポンプ２に供給可能な圧力値に設定される。これにより、原水比例制御弁１４よりも上流側の原水ラインＬ１において、原水Ｗ１の原水圧力は、一定圧力値となる。本実施形態においては、原水Ｗ１の原水圧力を、例えば、０．２～０．５ＭＰａの間の一定圧力値に設定している。 In the present embodiment, the control unit 30 controls the raw water side inverter 13 so that the raw water pump 12 discharges the raw water W1 at a predetermined constant pressure value. The constant pressure value of the raw water W1 applied by the raw water pump 12 is set to a pressure value at which the raw water W1 flowing through the raw water line L1 can be supplied to the pressurizing pump 2. Thereby, in the raw water line L1 upstream from the raw water proportional control valve 14, the raw water pressure of the raw water W1 becomes a constant pressure value. In the present embodiment, the raw water pressure of the raw water W1 is set to a constant pressure value between 0.2 and 0.5 MPa, for example.
　なお、本実施形態においては、原水ラインＬ１に原水ポンプ１２を設けたが、これに制限されない。供給源から供給される原水Ｗ１の原水圧力が十分に確保されていれば、原水ポンプ１２を設けなくてもよい。例えば、原水ラインＬ１の上流側において、水頭圧差を利用することで、原水Ｗ１の原水圧力を確保するように構成してもよい。 In addition, in this embodiment, although the raw | natural water pump 12 was provided in the raw | natural water line L1, it is not restrict | limited to this. If the raw water pressure of the raw water W1 supplied from the supply source is sufficiently secured, the raw water pump 12 may not be provided. For example, you may comprise so that the raw | natural water pressure of the raw | natural water W1 may be ensured by utilizing a water head pressure difference in the upstream of the raw | natural water line L1.
　原水比例制御弁１４は、合流部Ｊ２よりも上流側の原水ラインＬ１に設けられる。原水比例制御弁１４は、合流部Ｊ２よりも上流側の原水ラインＬ１を流通する原水Ｗ１の圧力を調整する弁である。ここで、合流部Ｊ２よりも上流側の原水ラインＬ１は、合流部Ｊ２を介して、循環水ラインＬ４に接続されている。循環水ラインＬ４は、接続部Ｊ１を介して、濃縮水ラインＬ３に接続されている。濃縮水ラインＬ３の定流量弁５よりも下流側の部分において、接続部Ｊ１と定流量弁５の二次側とが接続されている。つまり、合流部Ｊ２よりも上流側の原水ラインＬ１を流通する原水Ｗ１の圧力は、定流量弁５の二次側の圧力と同じであると看做すことができる。 The raw water proportional control valve 14 is provided in the raw water line L1 upstream from the junction J2. The raw water proportional control valve 14 is a valve that adjusts the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2. Here, the raw water line L1 on the upstream side of the junction J2 is connected to the circulating water line L4 via the junction J2. The circulating water line L4 is connected to the concentrated water line L3 via the connection portion J1. In the portion of the concentrated water line L3 on the downstream side of the constant flow valve 5, the connection portion J1 and the secondary side of the constant flow valve 5 are connected. That is, it can be considered that the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2 is the same as the pressure on the secondary side of the constant flow valve 5.
　原水比例制御弁１４は、合流部Ｊ２よりも上流側の原水ラインＬ１を流通する原水Ｗ１の原水圧力を調整することによって、定流量弁５（後述）の二次側の圧力を所定の設定圧力値に調整して、定流量弁５の一次側の圧力から二次側の圧力を減じた差圧（以下「定流量弁差圧」ともいう）を調整する。なお、定流量弁５の二次側の圧力は、原水比例制御弁１４と合流部Ｊ２との間に配置される二次側圧力センサＰＳ２（後述）により、検出二次側圧力値として検出される。検出二次側圧力値に基づいて、後述する制御部３０により、フィードバック制御が行われる。 The raw water proportional control valve 14 adjusts the raw water pressure of the raw water W1 flowing through the raw water line L1 upstream of the junction J2, thereby adjusting the secondary pressure of the constant flow valve 5 (described later) to a predetermined set pressure. The differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5 (hereinafter also referred to as “constant flow valve differential pressure”) is adjusted. Note that the secondary pressure of the constant flow valve 5 is detected as a detected secondary pressure value by a secondary pressure sensor PS2 (described later) disposed between the raw water proportional control valve 14 and the junction J2. The Based on the detected secondary pressure value, feedback control is performed by the control unit 30 described later.
　原水比例制御弁１４は、制御部３０と電気的に接続されている。原水比例制御弁１４の弁開度は、制御部３０から送信される駆動信号により制御される。制御部３０から電流値信号（例えば、４～２０ｍＡ）を原水比例制御弁１４に送信して、流路断面積を調整することにより、流動抵抗（すなわち、圧力損失）を徐々に変化させることができる。この調節により、原水比例制御弁１４は、合流部Ｊ２よりも上流側の原水ラインＬ１を流通する原水Ｗ１の圧力を調整する。 The raw water proportional control valve 14 is electrically connected to the control unit 30. The valve opening degree of the raw water proportional control valve 14 is controlled by a drive signal transmitted from the control unit 30. By transmitting a current value signal (for example, 4 to 20 mA) from the control unit 30 to the raw water proportional control valve 14 and adjusting the flow path cross-sectional area, the flow resistance (that is, pressure loss) can be gradually changed. it can. By this adjustment, the raw water proportional control valve 14 adjusts the pressure of the raw water W1 flowing through the raw water line L1 on the upstream side of the junction J2.
　原水比例制御弁１４の上流側を流通する原水Ｗ１は、前述の通り、所定の一定圧力値の原水圧力が確保されている。そのため、原水比例制御弁１４により調整される原水比例制御弁１４よりも下流側の原水圧力は、後述する制御部３０により、原水ポンプ１２により吐出される原水圧力の所定の一定圧力値以下となるように制御される。 The raw water W1 flowing upstream of the raw water proportional control valve 14 has a raw water pressure of a predetermined constant pressure value as described above. Therefore, the raw water pressure downstream of the raw water proportional control valve 14 adjusted by the raw water proportional control valve 14 is equal to or lower than a predetermined constant pressure value of the raw water pressure discharged by the raw water pump 12 by the control unit 30 described later. To be controlled.
　二次側圧力センサＰＳ２は、原水ラインＬ１における原水比例制御弁１４と合流部Ｊ２との間に配置されている。二次側圧力センサＰＳ２は、定流量弁５の二次側の圧力を検出二次側圧力値として検出する機器である。前述したように、合流部Ｊ２よりも上流側であって原水比例制御弁１４の下流側の原水ラインＬ１を流通する原水Ｗ１の圧力は、定流量弁５の二次側の圧力と同じである。そのため、二次側圧力センサＰＳ２は、原水比例制御弁１４と合流部Ｊ２との間において原水Ｗ１の圧力を検出することで、定流量弁５の二次側の圧力を検出二次側圧力値として検出することができる。二次側圧力センサＰＳ２は、制御部３０と電気的に接続されている。二次側圧力センサＰＳ２で検出された検出二次側圧力値は、制御部３０へ検出信号として送信される。 The secondary side pressure sensor PS2 is arranged between the raw water proportional control valve 14 and the junction J2 in the raw water line L1. The secondary side pressure sensor PS2 is a device that detects the secondary side pressure of the constant flow valve 5 as a detected secondary side pressure value. As described above, the pressure of the raw water W1 flowing through the raw water line L1 upstream of the junction J2 and downstream of the raw water proportional control valve 14 is the same as the pressure on the secondary side of the constant flow valve 5. . Therefore, the secondary pressure sensor PS2 detects the pressure of the raw water W1 between the raw water proportional control valve 14 and the junction J2, thereby detecting the secondary pressure of the constant flow valve 5 and the secondary pressure value. Can be detected as The secondary pressure sensor PS2 is electrically connected to the control unit 30. The detected secondary pressure value detected by the secondary pressure sensor PS2 is transmitted to the control unit 30 as a detection signal.
　なお、本実施形態においては、二次側圧力センサＰＳ２による、定流量弁５の二次側の圧力の検出位置を、原水比例制御弁１４と合流部Ｊ２との間の位置としたが、これに制限されない。二次側圧力センサＰＳ２は、定流量弁５の二次側の圧力が検出できれば、この位置に制限されない。定流量弁５の二次側の圧力は、原水ラインＬ１における原水比例制御弁１４と加圧ポンプ２との間を流通する原水Ｗ１の圧力や、濃縮水ラインＬ３における定流量弁５と接続部Ｊ１との間を流通する濃縮水Ｗ３の圧力や、循環水ラインＬ４を流通する濃縮水Ｗ３の一部Ｗ３１の圧力や、排水ラインＬ５における接続部Ｊ１と排水比例制御弁８との間を流通する濃縮水Ｗ３の残部Ｗ３２の圧力と、同じである。そのため、二次側圧力センサＰＳ２の検出位置は、定流量弁５の二次側の圧力を検出できる位置であれば、例えば、濃縮水ラインＬ３における定流量弁５と接続部Ｊ１との間の位置や、循環水ラインＬ４における接続部Ｊ１と合流部Ｊ２との間の位置などでもよい。 In this embodiment, the detection position of the secondary side pressure of the constant flow valve 5 by the secondary side pressure sensor PS2 is the position between the raw water proportional control valve 14 and the merging portion J2. Not limited to. The secondary pressure sensor PS2 is not limited to this position as long as the secondary pressure of the constant flow valve 5 can be detected. The pressure on the secondary side of the constant flow valve 5 is the pressure of the raw water W1 flowing between the raw water proportional control valve 14 and the pressurizing pump 2 in the raw water line L1, and the connection with the constant flow valve 5 in the concentrated water line L3. The pressure of the concentrated water W3 flowing between J1 and the pressure of a part W31 of the concentrated water W3 flowing through the circulating water line L4, and the connection between the connecting portion J1 and the drainage proportional control valve 8 in the drainage line L5 The pressure of the remaining portion W32 of the concentrated water W3 is the same. Therefore, if the detection position of the secondary side pressure sensor PS2 is a position where the pressure on the secondary side of the constant flow valve 5 can be detected, for example, between the constant flow valve 5 and the connection portion J1 in the concentrated water line L3. A position, the position between the connection part J1 and the junction part J2 in the circulating water line L4, etc. may be sufficient.
　加圧ポンプ２は、合流部Ｊ２よりも下流側の原水ラインＬ１に設けられる。加圧ポンプ２は、合流部Ｊ２よりも下流側の原水ラインＬ１において、原水ラインＬ１を流通する原水Ｗ１を吸入し、ＲＯ膜モジュール４へ向けて圧送（吐出）する装置である。加圧ポンプ２には、加圧側インバータ３から周波数が変換された駆動電力が供給される。加圧ポンプ２は、供給（入力）された駆動電力の周波数（以下、「駆動周波数」ともいう）に応じた回転速度で駆動される。 The pressurizing pump 2 is provided in the raw water line L1 on the downstream side of the junction J2. The pressurizing pump 2 is a device that sucks raw water W1 flowing through the raw water line L1 and feeds (discharges) the raw water W1 to the RO membrane module 4 in the raw water line L1 downstream of the junction J2. The pressurizing pump 2 is supplied with driving power whose frequency is converted from the pressurizing side inverter 3. The pressurizing pump 2 is driven at a rotational speed corresponding to the frequency (hereinafter also referred to as “driving frequency”) of the driving power supplied (input).
　加圧側インバータ３は、加圧ポンプ２に、周波数が変換された駆動電力を供給する電気回路（又はその回路を持つ装置）である。加圧側インバータ３は、制御部３０と電気的に接続されている。加圧側インバータ３には、制御部３０から指令信号が入力される。加圧側インバータ３は、制御部３０により入力された指令信号（電流値信号又は電圧値信号）に対応する駆動周波数の駆動電力を加圧ポンプ２に出力する。 The pressurizing side inverter 3 is an electric circuit (or a device having the circuit) that supplies the pressurizing pump 2 with driving power whose frequency is converted. The pressurizing side inverter 3 is electrically connected to the control unit 30. A command signal is input from the control unit 30 to the pressure side inverter 3. The pressurizing side inverter 3 outputs driving power having a driving frequency corresponding to the command signal (current value signal or voltage value signal) input by the control unit 30 to the pressurizing pump 2.
　吐出圧力センサＰＳ３は、加圧ポンプ２の吐出圧力（運転圧力）を検出吐出圧力値として検出する機器である。吐出圧力センサＰＳ３は、加圧ポンプ２の吐出側近傍に配置されている。本実施形態では、加圧ポンプ２から吐出された直後の原水Ｗ１の圧力を、加圧ポンプ２の吐出圧力とする。吐出圧力センサＰＳ３は、制御部３０と電気的に接続されている。吐出圧力センサＰＳ３で検出された原水Ｗ１の検出吐出圧力値は、制御部３０へ検出信号として送信される。 The discharge pressure sensor PS3 is a device that detects the discharge pressure (operating pressure) of the pressure pump 2 as a detected discharge pressure value. The discharge pressure sensor PS3 is disposed in the vicinity of the discharge side of the pressure pump 2. In the present embodiment, the pressure of the raw water W <b> 1 immediately after being discharged from the pressurizing pump 2 is set as the discharge pressure of the pressurizing pump 2. The discharge pressure sensor PS3 is electrically connected to the control unit 30. The detected discharge pressure value of the raw water W1 detected by the discharge pressure sensor PS3 is transmitted to the control unit 30 as a detection signal.
　本実施形態においては、第１流量センサＦＭ１が故障した場合に、第１流量センサＦＭ１の第１検出流量値を用いて実行される流量フィードバック水量制御（後述）に代えて、吐出圧力センサＰＳ３の検出吐出圧力値を用いて実行される圧力フィードバック水量制御（後述）を、バックアップとして実行することができる。本実施形態は、このバックアップのために、加圧ポンプ２の吐出圧力値（運転圧力値）を取得する吐出圧力センサＰＳ３を備えている。 In the present embodiment, when the first flow rate sensor FM1 fails, instead of the flow rate feedback water amount control (described later) executed using the first detected flow rate value of the first flow rate sensor FM1, the discharge pressure sensor PS3 Pressure feedback water amount control (described later) executed using the detected discharge pressure value can be executed as a backup. The present embodiment includes a discharge pressure sensor PS3 that acquires the discharge pressure value (operating pressure value) of the pressurizing pump 2 for this backup.
　ＲＯ膜モジュール４は、加圧ポンプ２から吐出された原水Ｗ１を、溶存塩類が除去された透過水Ｗ２と、溶存塩類が濃縮された濃縮水Ｗ３とに膜分離処理する設備である。ＲＯ膜モジュール４は、単一又は複数のＲＯ膜エレメント（不図示）を備える。ＲＯ膜モジュール４は、これらＲＯ膜エレメントにより原水Ｗ１を膜分離処理し、透過水Ｗ２及び濃縮水Ｗ３を製造する。 The RO membrane module 4 is a facility for subjecting the raw water W1 discharged from the pressure pump 2 to membrane separation treatment into permeated water W2 from which dissolved salts have been removed and concentrated water W3 from which dissolved salts have been concentrated. The RO membrane module 4 includes a single or a plurality of RO membrane elements (not shown). The RO membrane module 4 performs membrane separation treatment on the raw water W1 with these RO membrane elements to produce permeated water W2 and concentrated water W3.
　透過水ラインＬ２は、ＲＯ膜モジュール４で分離された透過水Ｗ２を送出するラインである。透過水ラインＬ２の上流側の端部は、ＲＯ膜モジュール４の二次側ポートに接続されている。透過水ラインＬ２の下流側の端部は、需要箇所の装置等に接続されている。透過水ラインＬ２には、流路切換弁１５、第１流量センサＦＭ１が設けられている。 Permeate water line L2 is a line for sending permeate water W2 separated by RO membrane module 4. The upstream end of the permeate line L2 is connected to the secondary port of the RO membrane module 4. The downstream end of the permeate line L2 is connected to a device or the like at the demand point. The permeate line L2 is provided with a flow path switching valve 15 and a first flow rate sensor FM1.
　流路切換弁１５は、ＲＯ膜モジュール４で分離された透過水Ｗ２を、需要箇所の装置等に送出する流路（採水流路）側、又は、透過水ラインＬ２から分岐させて透過水リターンラインＬ６を介してＲＯ膜モジュール４の上流側の原水ラインＬ１へ向けて流通させる流路（循環流路）側に切り換え可能な弁である。流路切換弁１５は、例えば、電動式又は電磁式の三方弁により構成される。流路切換弁１５は、制御部３０と電気的に接続されている。流路切換弁１５における流路の切り換えは、制御部３０から送信される流路切換信号により制御される。 The flow path switching valve 15 branches the permeated water W2 separated by the RO membrane module 4 from the flow path (water sampling flow path) side to send to a device or the like at the demand point or from the permeated water line L2, and returns the permeated water. This is a valve that can be switched to the flow path (circulation flow path) side that circulates toward the raw water line L1 upstream of the RO membrane module 4 via the line L6. The flow path switching valve 15 is configured by, for example, an electric or electromagnetic three-way valve. The flow path switching valve 15 is electrically connected to the control unit 30. Switching of the flow path in the flow path switching valve 15 is controlled by a flow path switching signal transmitted from the control unit 30.
　透過水リターンラインＬ６は、フラッシング運転の実行時において、透過水ラインＬ２に送出された透過水Ｗ２を、原水ラインＬ１における加圧ポンプ２よりも上流側に返送させるラインである。透過水リターンラインＬ６の上流側の端部は、流路切換弁１５に接続されている。透過水リターンラインＬ６の下流側の端部は、接続部Ｊ３において原水ラインＬ１に接続されている。接続部Ｊ３は、合流部Ｊ２と加圧ポンプ２との間に配置されている。透過水リターンラインＬ６には、逆止弁７が設けられている。 The permeated water return line L6 is a line that returns the permeated water W2 sent to the permeated water line L2 to the upstream side of the pressurizing pump 2 in the raw water line L1 during the flushing operation. The upstream end of the permeate return line L6 is connected to the flow path switching valve 15. The downstream end of the permeate return line L6 is connected to the raw water line L1 at the connection J3. The connection portion J3 is disposed between the junction portion J2 and the pressure pump 2. A check valve 7 is provided in the permeate return line L6.
　流路切換弁１５は、逆浸透膜分離装置１の通常運転時には、ＲＯ膜モジュール４で分離処理された透過水Ｗ２を需要箇所の装置等に送出するために、採水流路側に切り換えられるように制御部３０により制御される。 In the normal operation of the reverse osmosis membrane separation apparatus 1, the flow path switching valve 15 is switched to the water sampling flow path side in order to send the permeated water W2 separated by the RO membrane module 4 to a device or the like at the demand point. It is controlled by the control unit 30.
　また、流路切換弁１５は、逆浸透膜分離装置１の起動時やフラッシング運転の実行時においては、次のように制御部３０により制御される。起動時には、装置の始動時から安定した水を需要箇所の装置等に供給するため、流路切換弁１５を循環流路側に切り換えるように制御する。
　また、ＲＯ膜モジュール４の膜の汚れの付着による詰まり防止のため、定期的にフラッシングを行う。その際、流路切換弁１５を循環流路側に切り換えるように制御すると共に、排水比例制御弁８を開状態となるように制御した状態で、加圧ポンプ２を一定時間運転する。これにより、ＲＯ膜モジュール４の膜に付着した汚れを落とすことができる。 Further, the flow path switching valve 15 is controlled by the control unit 30 as follows when the reverse osmosis membrane separation device 1 is started or when the flushing operation is executed. At the time of start-up, control is performed so that the flow path switching valve 15 is switched to the circulation flow path side in order to supply stable water to the apparatus or the like at the demand point from the start of the apparatus.
Further, flushing is periodically performed to prevent clogging due to adhesion of dirt on the membrane of the RO membrane module 4. At that time, the pressure switching pump 15 is operated for a predetermined time in a state where the flow path switching valve 15 is controlled to be switched to the circulation flow path side and the drainage proportional control valve 8 is controlled to be in the open state. Thereby, the dirt adhering to the membrane of the RO membrane module 4 can be removed.
　第１流量センサＦＭ１は、透過水ラインＬ２を流通する透過水Ｗ２の流量を第１検出流量値として検出する機器である。第１流量センサＦＭ１は、透過水ラインＬ２に接続されている。第１流量センサＦＭ１は、制御部３０と電気的に接続されている。第１流量センサＦＭ１で検出された透過水Ｗ２の第１検出流量値は、制御部３０へパルス信号として送信される。第１流量センサＦＭ１として、例えば、流路ハウジング内に軸流羽根車又は接線羽根車（不図示）を配置したパルス発信式の流量センサを用いることができる。 1st flow sensor FM1 is an apparatus which detects the flow volume of the permeated water W2 which distribute | circulates the permeated water line L2 as a 1st detected flow value. The first flow sensor FM1 is connected to the permeate line L2. The first flow sensor FM1 is electrically connected to the control unit 30. The first detected flow rate value of the permeated water W2 detected by the first flow rate sensor FM1 is transmitted to the control unit 30 as a pulse signal. As the first flow rate sensor FM1, for example, a pulse transmission type flow rate sensor in which an axial flow impeller or a tangential impeller (not shown) is disposed in the flow path housing can be used.
　濃縮水ラインＬ３は、ＲＯ膜モジュール４で分離された濃縮水Ｗ３を送出するラインである。濃縮水ラインＬ３の上流側の端部は、ＲＯ膜モジュール４の一次側出口ポートに接続されている。また、濃縮水ラインＬ３の下流側は、接続部Ｊ１において、循環水ラインＬ４及び排水ラインＬ５に分岐している。 The concentrated water line L3 is a line for sending the concentrated water W3 separated by the RO membrane module 4. The upstream end of the concentrated water line L3 is connected to the primary outlet port of the RO membrane module 4. Further, the downstream side of the concentrated water line L3 branches to the circulating water line L4 and the drainage line L5 at the connection portion J1.
　濃縮水ラインＬ３には、上流側から下流側に向けて順に、一次側圧力センサＰＳ１、定流量弁５、接続部Ｊ１が設けられている。
　一次側圧力センサＰＳ１は、定流量弁５の一次側の圧力を検出一次側圧力値として検出する機器である。一次側圧力センサＰＳ１は、濃縮水ラインＬ３におけるＲＯ膜モジュール４と定流量弁５との間に配置されている。一次側圧力センサＰＳ１は、制御部３０と電気的に接続されている。一次側圧力センサＰＳ１で検出された原水Ｗ１の検出一次側圧力値は、制御部３０へ検出信号として送信される。 The concentrated water line L3 is provided with a primary pressure sensor PS1, a constant flow valve 5, and a connecting portion J1 in order from the upstream side to the downstream side.
The primary side pressure sensor PS1 is a device that detects the primary side pressure of the constant flow valve 5 as a detected primary side pressure value. The primary side pressure sensor PS1 is disposed between the RO membrane module 4 and the constant flow valve 5 in the concentrated water line L3. The primary side pressure sensor PS1 is electrically connected to the control unit 30. The detected primary pressure value of the raw water W1 detected by the primary pressure sensor PS1 is transmitted to the control unit 30 as a detection signal.
　定流量弁５は、濃縮水ラインＬ３を流通する濃縮水Ｗ３の流量を所定の一定流量値に保持するように調節する機器である。定流量弁５において保持される一定流量値は、一定流量値に幅がある概念であり、定流量弁における目標流量値のみに限られない。例えば、定流量機構の特性（例えば、材質や構造に起因する温度特性等）を考慮して、定流量弁における目標流量値に対して、±１０％程度の調節誤差を有するものを含む。定流量弁５は、補助動力や外部操作を必要とせずに一定流量値を保持するものであり、例えば、水ガバナの名称で呼ばれるものが挙げられる。なお、定流量弁５は、補助動力や外部操作により動作して、一定流量値を保持するものでもよい。 The constant flow valve 5 is a device that adjusts the flow rate of the concentrated water W3 flowing through the concentrated water line L3 so as to maintain a predetermined constant flow rate value. The constant flow value held in the constant flow valve 5 is a concept having a range in the constant flow value, and is not limited to the target flow value in the constant flow valve. For example, in consideration of the characteristics of the constant flow mechanism (for example, temperature characteristics caused by the material and structure), the constant flow mechanism includes those having an adjustment error of about ± 10% with respect to the target flow rate value. The constant flow valve 5 holds a constant flow value without requiring auxiliary power or external operation, and includes, for example, what is called by the name of a water governor. The constant flow valve 5 may be operated by auxiliary power or an external operation to hold a constant flow value.
　循環水ラインＬ４は、濃縮水ラインＬ３から分岐するラインであって、ＲＯ膜モジュール４で分離された濃縮水Ｗ３の一部Ｗ３１を、原水ラインＬ１におけるＲＯ膜モジュール４及び加圧ポンプ２よりも上流側の合流部Ｊ２に返送するラインである。循環水ラインＬ４の上流側の端部は、接続部Ｊ１において、濃縮水ラインＬ３に接続されている。また、循環水ラインＬ４の下流側の端部は、合流部Ｊ２において、原水ラインＬ１に接続されている。循環水ラインＬ４には、逆止弁６が設けられている。 The circulating water line L4 is a line branched from the concentrated water line L3, and a part W31 of the concentrated water W3 separated by the RO membrane module 4 is more than the RO membrane module 4 and the pressure pump 2 in the raw water line L1. This line is returned to the upstream junction J2. The upstream end of the circulating water line L4 is connected to the concentrated water line L3 at the connecting portion J1. Further, the downstream end of the circulating water line L4 is connected to the raw water line L1 at the junction J2. A check valve 6 is provided in the circulating water line L4.
　排水ラインＬ５は、接続部Ｊ１において濃縮水ラインＬ３から分岐され、ＲＯ膜モジュール４で分離された濃縮水Ｗ３の残部Ｗ３２を装置外（系外）に排出するラインである。排水ラインＬ５には、第２流量センサＦＭ２、排水流量調整手段としての排水比例制御弁８が設けられている。 The drainage line L5 is a line that is branched from the concentrated water line L3 at the connection portion J1 and discharges the remaining portion W32 of the concentrated water W3 separated by the RO membrane module 4 to the outside of the apparatus (outside the system). The drainage line L5 is provided with a second flow rate sensor FM2 and a drainage proportional control valve 8 as drainage flow rate adjusting means.
　第２流量センサＦＭ２は、排水ラインＬ５を流通する濃縮水Ｗ３の残部Ｗ３２の排水流量を第２検出流量値として検出する機器である。第２流量センサＦＭ２は、制御部３０と電気的に接続されている。第２流量センサＦＭ２で検出された濃縮水Ｗ３の残部Ｗ３２の第２検出流量値は、制御部３０へパルス信号として送信される。第２流量センサＦＭ２として、例えば、流路ハウジング内に軸流羽根車又は接線羽根車（不図示）を配置したパルス発信式の流量センサを用いることができる。 The second flow rate sensor FM2 is a device that detects the drainage flow rate of the remaining portion W32 of the concentrated water W3 flowing through the drainage line L5 as the second detected flow rate value. The second flow sensor FM2 is electrically connected to the control unit 30. The second detected flow rate value of the remaining portion W32 of the concentrated water W3 detected by the second flow rate sensor FM2 is transmitted to the control unit 30 as a pulse signal. As the second flow rate sensor FM2, for example, a pulse transmission type flow rate sensor in which an axial flow impeller or a tangential impeller (not shown) is disposed in the flow path housing can be used.
　排水比例制御弁８は、排水ラインＬ５から装置外へ排出する濃縮水Ｗ３の残部Ｗ３２の排水流量を調整可能な弁である。排水比例制御弁８は、排水ラインＬ５における第２流量センサＦＭ２よりも下流側に配置されている。排水比例制御弁８は、制御部３０と電気的に接続されている。排水比例制御弁８の弁開度は、制御部３０から送信される駆動信号により制御される。制御部３０から電流値信号（例えば、４～２０ｍＡ）を排水比例制御弁８に送信して、弁開度を制御することにより、濃縮水Ｗ３の残部Ｗ３２の排水流量を調整することができる。
　排水比例制御弁８における制御部３０による制御の詳細は後述する。 The drainage proportional control valve 8 is a valve capable of adjusting the drainage flow rate of the remaining portion W32 of the concentrated water W3 discharged from the drainage line L5 to the outside of the apparatus. The drainage proportional control valve 8 is disposed downstream of the second flow rate sensor FM2 in the drainage line L5. The drainage proportional control valve 8 is electrically connected to the control unit 30. The valve opening degree of the drainage proportional control valve 8 is controlled by a drive signal transmitted from the control unit 30. By sending a current value signal (for example, 4 to 20 mA) from the control unit 30 to the drainage proportional control valve 8 and controlling the valve opening, the drainage flow rate of the remaining portion W32 of the concentrated water W3 can be adjusted.
Details of the control by the control unit 30 in the drainage proportional control valve 8 will be described later.
　制御部３０は、ＣＰＵ及びメモリを含むマイクロプロセッサ（不図示）により構成される。以下、制御部３０の機能について説明する。 The control unit 30 is configured by a microprocessor (not shown) including a CPU and a memory. Hereinafter, functions of the control unit 30 will be described.
＜透過水Ｗ２の水量制御＞
　制御部３０は、透過水Ｗ２の水量制御を実行可能である。ＲＯ膜（逆浸透膜）に代表される半透膜は、原水の温度や膜の状態（細孔の閉塞や材質の酸化劣化）により水透過係数が変化する。そこで、逆浸透膜分離装置１では、原水の温度や膜の状態にかかわらず、透過水の流量を常に一定に保つために、透過水Ｗ２の水量制御が行われる。 <Water volume control of permeated water W2>
The control unit 30 can execute the water amount control of the permeated water W2. A semipermeable membrane represented by an RO membrane (reverse osmosis membrane) has a water permeability coefficient that varies depending on the temperature of raw water and the state of the membrane (blockage of pores and oxidative deterioration of material). Therefore, in the reverse osmosis membrane separation device 1, the water amount control of the permeate water W2 is performed in order to keep the flow rate of the permeate always constant regardless of the temperature of the raw water and the state of the membrane.
　制御部３０は、透過水Ｗ２の水量制御として、例えば、流量フィードバック水量制御、圧力フィードバック水量制御、又は温度フィードフォワード水量制御のいずれかを選択して実行できる。各水量制御の概要は、次の通りである。 The control unit 30 can select and execute, for example, flow rate feedback water amount control, pressure feedback water amount control, or temperature feedforward water amount control as the water amount control of the permeated water W2. The outline of each water quantity control is as follows.
流量フィードバック水量制御
　制御部３０（加圧ポンプ駆動制御部）は、加圧ポンプ２の駆動を制御する。制御部３０は、第１流量センサＦＭ１により検出された透過水Ｗ２の第１検出流量値が予め設定された目標流量値となるように、第１流量センサＦＭ１の第１検出流量値（系内の物理量）をフィードバック値として、加圧ポンプ２を駆動するための駆動周波数を演算する。そして、制御部３０は、駆動周波数の演算値に対応する指令信号（電流値信号又は電圧値信号）を加圧側インバータ３に出力する（以下、「流量フィードバック水量制御」ともいう）。なお、本水量制御における駆動周波数の演算には、例えば、速度形デジタルＰＩＤアルゴリズムを用いることができる。 The flow rate feedback water amount control control unit 30 (pressure pump drive control unit) controls the drive of the pressure pump 2. The control unit 30 controls the first detected flow rate value (in-system) of the first flow rate sensor FM1 so that the first detected flow rate value of the permeated water W2 detected by the first flow rate sensor FM1 becomes a preset target flow rate value. ) Is used as a feedback value to calculate the driving frequency for driving the pressurizing pump 2. Then, the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “flow rate feedback water amount control”). For example, a speed type digital PID algorithm can be used for calculation of the drive frequency in the main water amount control.
圧力フィードバック水量制御
　制御部３０（加圧ポンプ駆動制御部）は、透過水Ｗ２の流量が予め設定された目標流量値となるように、吐出圧力センサＰＳ３の検出吐出圧力値（系内の物理量）をフィードバック値として、加圧ポンプ２の駆動周波数を演算する。そして、制御部３０は、駆動周波数の演算値に対応する指令信号（電流値信号又は電圧値信号）を加圧側インバータ３に出力する（以下、「圧力フィードバック水量制御」ともいう）。なお、本水量制御における駆動周波数の演算には、例えば、速度形デジタルＰＩＤアルゴリズムを用いることができる。本実施形態においては、第１流量センサＦＭ１が故障した場合に、第１流量センサＦＭ１の第１検出流量値を用いて実行される流量フィードバック水量制御に代えて、吐出圧力センサＰＳ３の検出吐出圧力値を用いて実行される圧力フィードバック水量制御を、バックアップとして実行することができる。本実施形態は、バックアップに備えて、加圧ポンプ２の吐出圧力値（運転圧力値）を取得する吐出圧力センサＰＳ３を備えている。 The pressure feedback water amount control control unit 30 (pressure pump drive control unit) detects the detected discharge pressure value (physical amount in the system) of the discharge pressure sensor PS3 so that the flow rate of the permeated water W2 becomes a preset target flow rate value. Is used as a feedback value to calculate the driving frequency of the pressurizing pump 2. Then, the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “pressure feedback water amount control”). For example, a speed type digital PID algorithm can be used for calculation of the drive frequency in the main water amount control. In the present embodiment, when the first flow sensor FM1 fails, the detected discharge pressure of the discharge pressure sensor PS3 is used instead of the flow rate feedback water amount control executed using the first detected flow value of the first flow sensor FM1. Pressure feedback water volume control performed using the values can be performed as a backup. The present embodiment includes a discharge pressure sensor PS3 that acquires the discharge pressure value (operating pressure value) of the pressurizing pump 2 in preparation for backup.
温度フィードフォワード水量制御
　制御部３０（加圧ポンプ駆動制御部）は、透過水Ｗ２の流量が予め設定された目標流量値となるように、原水Ｗ１の温度センサ（不図示）の検出温度値（系内の物理量）をフィードフォワード値として、加圧ポンプ２の駆動周波数を演算する。そして、制御部３０は、駆動周波数の演算値に対応する指令信号（電流値信号又は電圧値信号）を加圧側インバータ３に出力する（以下、「温度フィードフォワード水量制御」ともいう）。 The temperature feedforward water amount control control unit 30 (pressurization pump drive control unit) detects a temperature value (not shown) detected by a temperature sensor (not shown) of the raw water W1 so that the flow rate of the permeated water W2 becomes a preset target flow rate value. The driving frequency of the pressurizing pump 2 is calculated using the physical quantity in the system as a feedforward value. Then, the control unit 30 outputs a command signal (current value signal or voltage value signal) corresponding to the calculated value of the drive frequency to the pressurizing side inverter 3 (hereinafter also referred to as “temperature feedforward water amount control”).
水温と加圧ポンプ２の吐出圧力との関係
　透過水Ｗ２の水量制御を行うシステムにおいては、水温が高い場合には、水の粘性が小さく、ＲＯ膜モジュールの水透過係数が高くなるため、加圧ポンプ２の吐出圧力（加圧ポンプ２の運転圧力、ＲＯ膜モジュール４の一次側入口ポートへの入力圧力）が低くなるように制御される。また、水温が低い場合には、水の粘性が大きく、ＲＯ膜モジュールの水透過係数が低くなるため、加圧ポンプ２の吐出圧力（加圧ポンプ２の運転圧力、ＲＯ膜モジュール４の一次側入口ポートへの入力圧力）が高くなるように制御される。 Relationship between the water temperature and the discharge pressure of the pressurizing pump 2 In the system that controls the amount of the permeated water W2, when the water temperature is high, the viscosity of the water is small and the water permeability coefficient of the RO membrane module is high. The discharge pressure of the pressure pump 2 (the operation pressure of the pressure pump 2 and the input pressure to the primary side inlet port of the RO membrane module 4) is controlled to be low. In addition, when the water temperature is low, the viscosity of water is large and the water permeability coefficient of the RO membrane module is low, so that the discharge pressure of the pressurizing pump 2 (the operating pressure of the pressurizing pump 2, the primary side of the RO membrane module 4) The input pressure to the inlet port is controlled to be high.
濃縮水Ｗ３の循環比の調節
　濃縮水Ｗ３の循環比とは、ＲＯ膜モジュール４の二次側ポートから流出する透過水Ｗ２の流量と一次側出口ポートから流出する濃縮水Ｗ３の流量との比率（濃縮水Ｗ３の流量／透過水Ｗ２の流量）である。循環比の所定値は、“５”程度が目安となる。
　ここで、本実施形態においては、濃縮水ラインＬ３には、定流量弁５が設けられている。そのため、定流量弁５で濃縮水Ｗ３の流量を一定に保持しながら、前述したいずれかの水量制御により透過水Ｗ２の流量を一定に保持することで、濃縮水Ｗ３の循環比は、所定値に調節されることになる。 Adjustment of the circulation ratio of the concentrated water W3 The circulation ratio of the concentrated water W3 is the ratio between the flow rate of the permeated water W2 flowing out from the secondary side port of the RO membrane module 4 and the flow rate of the concentrated water W3 flowing out from the primary side outlet port. (Flow rate of concentrated water W3 / flow rate of permeated water W2). The predetermined value of the circulation ratio is about “5”.
Here, in this embodiment, the constant flow valve 5 is provided in the concentrated water line L3. Therefore, the circulation ratio of the concentrated water W3 is set to a predetermined value by holding the flow rate of the permeated water W2 constant by any of the above-described water amount control while holding the flow rate of the concentrated water W3 constant by the constant flow valve 5. Will be adjusted to.
＜透過水Ｗ２の回収率制御＞
　透過水Ｗ２の回収率とは、ＲＯ膜モジュール４に供給される原水Ｗ１の流量に対する透過水Ｗ２の流量の比率（透過水Ｗ２の流量／原水Ｗ１の流量）である。透過水Ｗ２の回収率制御は、ＲＯ膜モジュール４の透水能力を維持するために、透過水Ｗ２の回収率を調整して、膜面へのスケールの析出やファウリング（膜面汚れ）を防止しながら運転する制御である。 <Recovery rate control of permeate W2>
The recovery rate of the permeated water W2 is a ratio of the flow rate of the permeated water W2 to the flow rate of the raw water W1 supplied to the RO membrane module 4 (flow rate of the permeated water W2 / flow rate of the raw water W1). Permeate W2 recovery rate control adjusts the recovery rate of permeate W2 to maintain the water permeability of the RO membrane module 4 to prevent scale deposition and fouling on the membrane surface. It is control to drive while.
　制御部３０は、透過水Ｗ２の回収率制御として、例えば、温度フィードフォワード回収率制御、水質フィードフォワード、又は水質フィードバック回収率制御のいずれかを選択して実行できる。各回収率制御の概要は、次の通りである。 The control unit 30 can select and execute, for example, temperature feedforward recovery rate control, water quality feedforward control, or water quality feedback recovery rate control as the recovery rate control of the permeated water W2. The outline of each recovery rate control is as follows.
温度フィードフォワード回収率制御
　制御部３０は、予め取得された原水Ｗ１のシリカ濃度、及び温度センサ（図示せず）の検出温度値から決定したシリカ溶解度に基づいて、濃縮水Ｗ３におけるシリカの許容濃縮倍率を演算する。そして、制御部３０は、許容濃縮倍率の演算値、及び透過水Ｗ２の目標流量値から排水流量を演算し、濃縮水Ｗ３の実際排水流量（第２流量センサＦＭ２の第２検出流量値）が排水流量の演算値（目標排水流量）となるように、排水比例制御弁８の弁開度を制御する（以下、「温度フィードフォワード回収率制御」ともいう）。制御部３０は、温度フィードフォワード回収率制御を実行する場合、逆浸透膜分離装置１においては、透過水Ｗ２の回収率を最大としつつ、ＲＯ膜モジュール４におけるシリカ系スケールの析出をより確実に抑制することができる。 The temperature feedforward recovery rate control control unit 30 allows permissible concentration of silica in the concentrated water W3 based on the silica concentration determined from the silica concentration of the raw water W1 acquired in advance and the detected temperature value of a temperature sensor (not shown). Calculate the magnification. Then, the control unit 30 calculates the drainage flow rate from the calculated value of the allowable concentration magnification and the target flow rate value of the permeated water W2, and the actual drainage flow rate of the concentrated water W3 (the second detected flow rate value of the second flow rate sensor FM2) is obtained. The valve opening degree of the drainage proportional control valve 8 is controlled so as to be a calculated value of the drainage flow rate (target drainage flow rate) (hereinafter also referred to as “temperature feedforward recovery rate control”). In the reverse osmosis membrane separation device 1, when the control unit 30 performs the temperature feedforward recovery rate control, the silica membrane scale deposition in the RO membrane module 4 is more reliably performed while maximizing the recovery rate of the permeate W2. Can be suppressed.
水質フィードフォワード回収率制御
　制御部３０は、予め取得された炭酸カルシウムの溶解度、及び硬度センサ（不図示）の測定硬度値に基づいて、濃縮水Ｗ３における炭酸カルシウムの許容濃縮倍率を演算する。そして、制御部３０は、許容濃縮倍率の演算値、及び透過水Ｗ２の目標流量値から排水流量を演算し、濃縮水Ｗ３の実際排水量（第２流量センサＦＭ２の第２検出流量値）が排水流量の演算値（目標排水流量）となるように、排水比例制御弁８の弁開度を制御する（以下、「水質フィードフォワード回収率制御」ともいう）。制御部３０は、水質フィードフォワード回収率制御を実行する場合、仮に前段に硬水軟化装置（不図示）が配置された場合に、前段の硬水軟化装置からの硬度リーク量が増加した場合でも、逆浸透膜分離装置１においては、透過水Ｗ２の回収率を最大としつつ、ＲＯ膜モジュール４における炭酸カルシウム系スケールの析出をより確実に抑制することができる。 The water quality feedforward recovery rate control control unit 30 calculates the allowable concentration rate of calcium carbonate in the concentrated water W3 based on the previously obtained solubility of calcium carbonate and the measured hardness value of a hardness sensor (not shown). Then, the control unit 30 calculates the drainage flow rate from the calculated value of the allowable concentration magnification and the target flow rate value of the permeated water W2, and the actual drainage amount of the concentrated water W3 (the second detected flow rate value of the second flow rate sensor FM2) is drained. The valve opening degree of the drainage proportional control valve 8 is controlled so as to be the calculated value of the flow rate (target drainage flow rate) (hereinafter also referred to as “water quality feedforward recovery rate control”). When the water quality feedforward recovery rate control is executed, the control unit 30 reverses even if the amount of hardness leak from the preceding water softening device is increased if a water softening device (not shown) is disposed in the previous stage. In the osmosis membrane separator 1, precipitation of calcium carbonate scale in the RO membrane module 4 can be more reliably suppressed while maximizing the recovery rate of the permeated water W2.
水質フィードバック回収率制御
　制御部３０は、透過水Ｗ２の測定電気伝導率値が予め設定された目標電気伝導率となるように、排水比例制御弁８の弁開度をダイレクトに制御する（以下、「水質フィードバック回収率制御」ともいう）。なお、本制御における弁開度の決定には、例えば、速度形デジタルＰＩＤアルゴリズムを用いることができる。制御部３０は、水質フィードバック回収率制御を実行するため、逆浸透膜分離装置１においては、透過水Ｗ２に要求される水質を満たしつつ、透過水Ｗ２の回収率を最大限にまで高めることができる。 The water quality feedback recovery rate control control unit 30 directly controls the valve opening degree of the drainage proportional control valve 8 so that the measured electrical conductivity value of the permeated water W2 becomes a preset target electrical conductivity (hereinafter, referred to as “the measured electrical conductivity value”). Also called “water quality feedback recovery rate control”). For example, a speed type digital PID algorithm can be used to determine the valve opening in this control. Since the control unit 30 performs water quality feedback recovery rate control, the reverse osmosis membrane separation device 1 can increase the recovery rate of the permeated water W2 to the maximum while satisfying the water quality required for the permeated water W2. it can.
＜排水比例制御弁８による排水流量の調節制御＞
　本調節制御は、前述した回収率制御のうち、温度フィードフォワード回収率制御又は水質フィードフォワード回収率制御に付随して実行される。
　制御部３０（排水制御部）は、第２流量センサＦＭ２の第２検出流量値が、前述した回収率制御で決定した排水流量の演算値（目標排水流量）となるように、排水流量調整手段としての排水比例制御弁８の弁開度を流量フィードバック制御する。なお、本調節制御における弁開度の演算には、例えば、速度形デジタルＰＩＤアルゴリズムを用いることができる。 <Drainage flow rate adjustment control using drainage proportional control valve 8>
This adjustment control is executed in association with the temperature feedforward recovery rate control or the water quality feedforward recovery rate control in the recovery rate control described above.
The control unit 30 (drainage control unit) is configured to adjust the drainage flow rate so that the second detected flow rate value of the second flow rate sensor FM2 becomes the calculated value (target drainage flow rate) of the drainage flow rate determined by the recovery rate control described above. The flow rate feedback control of the valve opening degree of the drainage proportional control valve 8 is performed. For example, a speed type digital PID algorithm can be used for the calculation of the valve opening degree in this adjustment control.
＜透過水Ｗ２の水量制御及び回収率制御の組み合わせの制御例＞
　透過水Ｗ２の水量制御及び回収率制御は、組み合わされて実行される。
　「流量フィードバック水量制御」と「温度フィードフォワード回収率制御」とが組み合わされて実行される第１制御パターンや、「圧力フィードバック水量制御」と「水質フィードフォワード回収率制御」とが組み合わされて実行される第２制御パターンや、「温度フィードフォワード水量制御」と「水質フィードバック回収率制御」とが組み合わされて実行される第３制御パターンが、例示される。なお、本発明では、第１制御パターン～第３制御パターン以外の組み合わせを排除するものではない。
　第１制御パターンにおいては、温度フィードフォワード回収率制御は、流量フィードバック水量制御と並行して実行される。第２制御パターンにおいては、温度フィードフォワード回収率制御は、圧力フィードバック水量制御と並行して実行される。第３制御パターンにおいては、水質フィードバック回収率制御は、温度フィードフォワード水量制御と並行して実行される。 <Control example of combination of water amount control and recovery rate control of permeate W2>
The water amount control and the recovery rate control of the permeated water W2 are executed in combination.
A first control pattern that is executed in combination with “flow rate feedback water amount control” and “temperature feedforward recovery rate control”, or a combination of “pressure feedback water amount control” and “water quality feedforward recovery rate control” The second control pattern to be executed and the third control pattern executed in combination with “temperature feedforward water amount control” and “water quality feedback recovery rate control” are exemplified. In the present invention, combinations other than the first to third control patterns are not excluded.
In the first control pattern, the temperature feedforward recovery rate control is executed in parallel with the flow rate feedback water amount control. In the second control pattern, the temperature feedforward recovery rate control is executed in parallel with the pressure feedback water amount control. In the third control pattern, the water quality feedback recovery rate control is executed in parallel with the temperature feedforward water amount control.
＜原水比例制御弁１４による原水圧力の調整制御＞
　まず、本発明において、原水比例制御弁１４により原水Ｗ１の原水圧力の調整制御を行う理由について、以下に説明する。
　濃縮水ラインＬ３に定流量弁５が設けられる本実施形態においては、定流量弁５の二次側の圧力が原水ラインＬ１の原水圧力と同じになっている。そのため、原水Ｗ１の原水圧力が高い場合には、濃縮水ラインＬ３に設けられる定流量弁５の一次側と二次側との圧力差が小さくなり、前記定流量弁差圧を確保できずに、濃縮水Ｗ３の一部Ｗ３１を、循環水ラインＬ４を介して原水ラインＬ１の合流部Ｊ２に返送できないことになる。 <Control of raw water pressure by the raw water proportional control valve 14>
First, the reason why adjustment control of the raw water pressure of the raw water W1 is performed by the raw water proportional control valve 14 in the present invention will be described below.
In the present embodiment in which the constant flow valve 5 is provided in the concentrated water line L3, the pressure on the secondary side of the constant flow valve 5 is the same as the raw water pressure in the raw water line L1. Therefore, when the raw water pressure of the raw water W1 is high, the pressure difference between the primary side and the secondary side of the constant flow valve 5 provided in the concentrated water line L3 becomes small, and the constant flow valve differential pressure cannot be secured. The part W31 of the concentrated water W3 cannot be returned to the junction J2 of the raw water line L1 via the circulating water line L4.
　これに対して、原水ラインＬ１を流通する原水Ｗ１の原水圧力を所定の一定圧力値に減圧する減圧弁（不図示）を用いて、原水Ｗ１の原水圧力を所定の一定圧力値まで減圧して、定流量弁５の二次側の圧力を下げることで、定流量弁５の一次側と二次側とにおいて、前記定流量弁差圧が所定差圧以上になるように調整することが考えられる。 On the other hand, the raw water pressure of the raw water W1 is reduced to a predetermined constant pressure value by using a pressure reducing valve (not shown) that reduces the raw water pressure of the raw water W1 flowing through the raw water line L1 to a predetermined constant pressure value. By adjusting the pressure on the secondary side of the constant flow valve 5, it is considered that the constant flow valve differential pressure is adjusted to be equal to or higher than a predetermined differential pressure on the primary side and the secondary side of the constant flow valve 5. It is done.
　ここで、原水Ｗ１の温度が低い場合には、原水Ｗ１の温度が高い場合と比べて、水の粘性が高く、ＲＯ膜モジュール４の水透過係数が低くなるため、透過水Ｗ２の水量制御を行うシステムにおいては、加圧ポンプ２の吐出圧力（加圧ポンプ２の運転圧力、ＲＯ膜モジュール４の一次側入口ポートへの入力圧力）が高くなるように制御される。一方、原水Ｗ１の水温によらず、減圧弁（不図示）により減圧される原水の原水圧力は、所定の一定圧力値に調整されている。そのため、原水Ｗ１の温度が低い場合には、原水Ｗ１の温度が高い場合と比べて、定流量弁５の一次側の圧力は、定流量弁５の二次側の圧力に対して、十分に高くなる。また、定流量弁５の二次側の圧力は、原水圧力が減圧されているため、低くなる。これにより、原水Ｗ１の温度が低い場合には、原水Ｗ１の温度が高い場合と比べて、定流量弁５の一次側と二次側とにおいて、定流量弁差圧は、所定差圧を大きく超えて余裕をもって確保される。 Here, when the temperature of the raw water W1 is low, the water viscosity is higher and the water permeability coefficient of the RO membrane module 4 is lower than when the temperature of the raw water W1 is high. In the system to be performed, the discharge pressure of the pressurizing pump 2 (the operating pressure of the pressurizing pump 2, the input pressure to the primary side inlet port of the RO membrane module 4) is controlled to be high. On the other hand, the raw water pressure of the raw water reduced by a pressure reducing valve (not shown) is adjusted to a predetermined constant pressure value regardless of the water temperature of the raw water W1. Therefore, when the temperature of the raw water W1 is low, the pressure on the primary side of the constant flow valve 5 is sufficiently higher than the pressure on the secondary side of the constant flow valve 5 compared to the case where the temperature of the raw water W1 is high. Get higher. Further, the pressure on the secondary side of the constant flow valve 5 is low because the raw water pressure is reduced. Thereby, when the temperature of the raw water W1 is low, the constant flow valve differential pressure on the primary side and the secondary side of the constant flow valve 5 is larger than the predetermined differential pressure when compared with the case where the temperature of the raw water W1 is high. It is secured with a margin.
　濃縮水ラインＬ３に定流量弁５が設けられる技術においては、原水Ｗ１の温度が低い場合に、前記定流量弁差圧を十分に確保できるにもかかわらず、加圧ポンプ２の上流側において、原水Ｗ１の原水圧力を減圧弁（不図示）により、原水Ｗ１の温度が高い場合と同じ所定の一定圧力値に減圧することになる。一方で、減圧弁（不図示）の下流側の原水ラインＬ１において、減圧弁（不図示）で減圧された原水を加圧ポンプ２により加圧する。原水Ｗ１の温度が低い場合において、前記定流量弁差圧が必要以上に大きくなくても、前記定流量弁差圧を所定差圧以上に確保できれば十分である。 In the technique in which the constant flow valve 5 is provided in the concentrated water line L3, when the temperature of the raw water W1 is low, the constant flow valve differential pressure can be sufficiently secured, but on the upstream side of the pressurizing pump 2, The raw water pressure of the raw water W1 is reduced by a pressure reducing valve (not shown) to the same predetermined constant pressure value as when the temperature of the raw water W1 is high. On the other hand, in the raw water line L1 downstream of the pressure reducing valve (not shown), the raw water decompressed by the pressure reducing valve (not shown) is pressurized by the pressurizing pump 2. When the temperature of the raw water W1 is low, even if the constant flow valve differential pressure is not larger than necessary, it is sufficient if the constant flow valve differential pressure can be secured above a predetermined differential pressure.
　このため、原水Ｗ１の温度が低い場合に、前記定流量弁差圧を確保しつつ、ＲＯ膜モジュール４に向けて流通させるために、原水Ｗ１の原水圧力を高いまま有効に利用できれば、原水Ｗ１に原水圧力を圧送する加圧ポンプ２の消費電力を低減できる。 Therefore, if the raw water W1 is low and the raw water pressure of the raw water W1 can be effectively used while being high in order to distribute the raw water W1 toward the RO membrane module 4 while ensuring the constant flow valve differential pressure, the raw water W1. The power consumption of the pressurizing pump 2 that pumps the raw water pressure can be reduced.
　以上の説明のように、前記定流量弁差圧を確保しつつ、原水Ｗ１の温度が低い場合であっても、原水ラインＬ１を流通する原水Ｗ１の原水圧力を有効に利用するために、本発明においては、制御部３０（原水圧力制御部）は、検出差圧値を演算（検出）し、検出差圧値が所定の設定差圧値以上となる範囲で原水Ｗ１の圧力が高くなるように、原水比例制御弁１４の弁開度（流路断面積）を調整するように制御する。 As described above, in order to effectively use the raw water pressure of the raw water W1 flowing through the raw water line L1, even if the temperature of the raw water W1 is low while ensuring the constant flow valve differential pressure, In the present invention, the control unit 30 (raw water pressure control unit) calculates (detects) the detected differential pressure value so that the pressure of the raw water W1 increases within a range where the detected differential pressure value is equal to or greater than a predetermined set differential pressure value. Next, control is performed so as to adjust the valve opening degree (flow passage cross-sectional area) of the raw water proportional control valve 14.
　検出差圧値は、定流量弁５の一次側の圧力と二次側の圧力との差圧（前記定流量弁差圧）である。検出差圧値は、二次側圧力センサＰＳ２により検出された検出二次側圧力値と、一次側圧力センサＰＳ１により検出された検出一次側圧力値と、に基づいて演算される。 The detected differential pressure value is a differential pressure between the primary side pressure and the secondary side pressure of the constant flow valve 5 (the constant flow valve differential pressure). The detected differential pressure value is calculated based on the detected secondary pressure value detected by the secondary pressure sensor PS2 and the detected primary pressure value detected by the primary pressure sensor PS1.
　そして、制御部３０は、検出差圧値が所定の設定差圧値以上となる範囲で原水Ｗ１の原水圧力が高くなる圧力値となるように、原水比例制御弁１４の弁開度（流路断面積）を調整するように制御する。設定差圧値は、定流量弁５の一次側の圧力から二次側の圧力を減じた差圧値である。設定差圧値は、定流量弁５の一次側から二次側に濃縮水Ｗ３が流れることが可能な下限の値が設定される。本実施形態においては、設定差圧値を、例えば、０．２Ｍｐａに設定する。
　なお、本調整制御における弁開度の演算には、例えば、速度形デジタルＰＩＤアルゴリズムを用いることができる。 And the control part 30 is the valve opening degree (flow path) of the raw | natural water proportional control valve 14 so that it may become a pressure value from which the raw | natural water pressure of the raw | natural water W1 becomes high in the range from which a detected differential pressure value becomes more than predetermined setting differential pressure value. Control to adjust the cross-sectional area. The set differential pressure value is a differential pressure value obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5. As the set differential pressure value, a lower limit value at which the concentrated water W3 can flow from the primary side to the secondary side of the constant flow valve 5 is set. In the present embodiment, the set differential pressure value is set to 0.2 Mpa, for example.
For example, a speed type digital PID algorithm can be used for calculation of the valve opening degree in the adjustment control.
　次に、制御部３０による定流量弁５の一次側と二次側との差圧を調整するために原水比例制御弁１４の弁開度を調節する制御について説明する。図２は、制御部３０において原水比例制御弁１４を制御することで定流量弁５の一次側の圧力から二次側の圧力を減じた差圧を調整する場合の処理手順を示すフローチャートである。図２に示すフローチャートの処理は、逆浸透膜分離装置１の運転中において、繰り返し実行される。 Next, control for adjusting the opening degree of the raw water proportional control valve 14 in order to adjust the differential pressure between the primary side and the secondary side of the constant flow valve 5 by the control unit 30 will be described. FIG. 2 is a flowchart showing a processing procedure when adjusting the differential pressure obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5 by controlling the raw water proportional control valve 14 in the control unit 30. . The process of the flowchart shown in FIG. 2 is repeatedly performed during the operation of the reverse osmosis membrane separation device 1.
　本フローチャートにおける逆浸透膜分離装置１の運転中においては、原水ポンプ１２は、所定の圧力値（例えば、０．３ＭＰａ）で原水Ｗ１を吐出するように制御されている。
　また、本実施形態の逆浸透膜分離装置１の起動時において、原水比例制御弁１４の弁開度を全開（弁開度１００％）に設定している。なお、原水比例制御弁１４の弁開度を全開（弁開度１００％）にしても、原水比例制御弁１４の流路断面積が原水比例制御弁１４の上流側の流路よりも小さい場合には、原水ラインＬ１を流通する原水Ｗ１の原水圧力が原水比例制御弁１４を通過後に低下する場合がある。そのため、原水比例制御弁１４における原水圧力の低下を見込んで、原水ポンプ１２の吐出圧力を設定してもよい。本実施形態においては、原水比例制御弁１４の弁開度を全開としているため、起動時において、原水比例制御弁１４の下流側の原水圧力の圧力値は、原水比例制御弁１４の弁開度が全開の場合から低下させない圧力値となる。これにより、原水ラインＬ１において、原水Ｗ１の原水圧力が原水比例制御弁１４の弁開度が全開の場合から低下させない圧力値で、原水Ｗ１は、加圧ポンプ２に向けて流通される。 During operation of the reverse osmosis membrane separation device 1 in this flowchart, the raw water pump 12 is controlled to discharge the raw water W1 at a predetermined pressure value (for example, 0.3 MPa).
In addition, when the reverse osmosis membrane separation device 1 of the present embodiment is started, the valve opening degree of the raw water proportional control valve 14 is set to fully open (valve opening degree 100%). In addition, even if the valve opening degree of the raw water proportional control valve 14 is fully opened (valve opening degree 100%), the flow passage cross-sectional area of the raw water proportional control valve 14 is smaller than the flow path upstream of the raw water proportional control valve 14. In some cases, the raw water pressure of the raw water W1 flowing through the raw water line L1 may decrease after passing through the raw water proportional control valve 14. Therefore, the discharge pressure of the raw water pump 12 may be set in anticipation of a decrease in the raw water pressure in the raw water proportional control valve 14. In this embodiment, since the valve opening of the raw water proportional control valve 14 is fully open, the pressure value of the raw water pressure downstream of the raw water proportional control valve 14 at the time of startup is the valve opening of the raw water proportional control valve 14. The pressure value does not decrease from when fully open. Thereby, in the raw water line L1, the raw water W1 is circulated toward the pressurizing pump 2 at a pressure value that does not decrease the raw water pressure of the raw water W1 from the case where the opening degree of the raw water proportional control valve 14 is fully open.
　ステップＳ１において、制御部３０は、透過水Ｗ２の水量制御として、例えば、前述したように、流量フィードバック水量制御、圧力フィードバック水量制御、又は温度フィードフォワード水量制御を実行する。 In step S1, the control unit 30 performs flow rate feedback water amount control, pressure feedback water amount control, or temperature feedforward water amount control as described above, for example, as the water amount control of the permeated water W2.
　ステップＳ２において、制御部３０は、透過水Ｗ２の水量制御と並行して実行される回収率制御を実行する。制御部３０は、透過水Ｗ２の回収率制御として、例えば、前述したように、温度フィードフォワード回収率制御、水質フィードフォワード、又は水質フィードバック回収率制御を実行する。 In step S2, the control unit 30 executes recovery rate control that is executed in parallel with the water amount control of the permeated water W2. For example, as described above, the control unit 30 performs temperature feedforward recovery rate control, water quality feedforward control, or water quality feedback recovery rate control as the recovery rate control of the permeated water W2.
　ステップＳ３において、制御部３０は、二次側圧力センサＰＳ２で検出された定流量弁５の二次側の検出二次側圧力値を取得する。 In step S3, the control unit 30 acquires the detected secondary pressure value on the secondary side of the constant flow valve 5 detected by the secondary pressure sensor PS2.
　ステップＳ４において、制御部３０は、一次側圧力センサＰＳ１で検出された定流量弁５の一次側の検出一次側圧力値を取得する。 In step S4, the control unit 30 acquires the detected primary pressure value on the primary side of the constant flow valve 5 detected by the primary pressure sensor PS1.
　ステップＳ５において、制御部３０は、ステップＳ３において取得した検出二次側圧力値と、ステップＳ４において取得した検出一次側圧力値とに基づいて、検出差圧値を演算（検出）する。検出差圧値は、定流量弁５の一次側の圧力から二次側の圧力を減じた差圧の値である。 In step S5, the control unit 30 calculates (detects) the detected differential pressure value based on the detected secondary pressure value acquired in step S3 and the detected primary pressure value acquired in step S4. The detected differential pressure value is a differential pressure value obtained by subtracting the secondary pressure from the primary pressure of the constant flow valve 5.
　ステップＳ６において、制御部３０は、ステップＳ５で演算した検出差圧値が所定の設定差圧値（例えば、０．２ＭＰａ）以上となる範囲で原水Ｗ１の圧力が高くなるように、原水比例制御弁１４の弁開度（流路断面積）を調整するように制御する。これにより、定流量弁５の一次側の圧力と二次側の圧力との差圧を確保した状態で、原水Ｗ１の原水圧力を原水比例制御弁１４の下流側において高くすることができる。そのため、原水Ｗ１の圧力を有効に使用することができる。
　ステップＳ６の後に、本フローチャートの処理は終了する（ステップＳ１へリターンする）。 In step S6, the control unit 30 controls the raw water proportional control so that the pressure of the raw water W1 increases in a range where the detected differential pressure value calculated in step S5 is equal to or higher than a predetermined set differential pressure value (for example, 0.2 MPa). Control is performed so as to adjust the valve opening (flow passage cross-sectional area) of the valve 14. Accordingly, the raw water pressure of the raw water W1 can be increased on the downstream side of the raw water proportional control valve 14 while ensuring the differential pressure between the primary pressure and the secondary pressure of the constant flow valve 5. Therefore, the pressure of the raw water W1 can be used effectively.
After step S6, the process of this flowchart ends (returns to step S1).
　上述した本実施形態に係る逆浸透膜分離装置１によれば、例えば、以下のような効果が得られる。
　本実施形態に係る逆浸透膜分離装置１においては、ＲＯ膜モジュール４と、原水ラインＬ１と、透過水ラインＬ２と、濃縮水ラインＬ３と、濃縮水ラインＬ３から分岐されＲＯ膜モジュール４で分離された濃縮水Ｗ３の一部Ｗ３１を原水ラインＬ１の合流部Ｊ２に返送する循環水ラインＬ４と、濃縮水ラインＬ３から分岐される排水ラインＬ５と、合流部Ｊ２よりも上流側の原水ラインＬ１を流通する原水Ｗ１の圧力を調整する原水比例制御弁１４と、濃縮水ラインＬ３を流通する濃縮水Ｗ３の流量を所定の一定流量値に保持する定流量弁５と、定流量弁５の一次側の圧力と二次側の圧力との差圧を検出差圧値として検出する一次側圧力センサＰＳ１，二次側圧力センサＰＳ２及び制御部３０と、検出差圧値が所定の設定差圧以上になる範囲で原水の圧力が高くなるように、原水比例制御弁１４を制御する制御部３０と、を備える。 According to the reverse osmosis membrane separation device 1 according to this embodiment described above, for example, the following effects can be obtained.
In the reverse osmosis membrane separation apparatus 1 according to the present embodiment, the RO membrane module 4, the raw water line L1, the permeate water line L2, the concentrated water line L3, and the concentrated water line L3 are branched and separated by the RO membrane module 4. A part of the concentrated water W3 W31 is returned to the merging portion J2 of the raw water line L1, a circulating water line L4, a drain line L5 branched from the concentrated water line L3, and a raw water line L1 upstream from the merging portion J2. The raw water proportional control valve 14 for adjusting the pressure of the raw water W1 that flows through the water, the constant flow valve 5 that maintains the flow rate of the concentrated water W3 that flows through the concentrated water line L3 at a predetermined constant flow value, and the primary of the constant flow valve 5 Primary side pressure sensor PS1, secondary side pressure sensor PS2, and control unit 30 for detecting the differential pressure between the primary side pressure and the secondary side pressure as the detected differential pressure value, and the detected differential pressure value is greater than or equal to a predetermined set differential pressure Range As the pressure of the raw water is high, and a control unit 30 for controlling the raw water proportional control valve 14, the.
　そのため、原水比例制御弁１４を制御することで、前記定流量弁差圧を、定流量弁５の一次側から二次側に濃縮水Ｗ３が流れる差圧となるように、調整することができる。また、原水Ｗ１の温度が低い場合において、原水Ｗ１の原水圧力を有効に利用して、加圧ポンプ２の負荷を下げて、加圧ポンプ２の吐出圧力を小さくできる。よって、加圧ポンプ２の消費電力を低減できる。つまり、原水Ｗ１の温度が低くなるに従って原水比例制御弁１４の弁開度を大きくする制御を行うことで、減圧弁などを用いて原水Ｗ１の原水圧力の減圧を行わなくてよいため、加圧ポンプ２の吐出圧力を昇圧することが軽減され、加圧ポンプ２の消費電力の低減が可能となる。
　これにより、定流量弁５の一次側と二次側の差圧を確保しつつ、原水ラインＬ１を流通する原水Ｗ１の原水圧力を有効に利用することができる。 Therefore, by controlling the raw water proportional control valve 14, the constant flow valve differential pressure can be adjusted so that the concentrated water W 3 flows from the primary side to the secondary side of the constant flow valve 5. . Further, when the temperature of the raw water W1 is low, the raw water pressure of the raw water W1 can be effectively used to reduce the load of the pressurizing pump 2 and reduce the discharge pressure of the pressurizing pump 2. Therefore, the power consumption of the pressurizing pump 2 can be reduced. In other words, since the opening degree of the raw water proportional control valve 14 is increased as the temperature of the raw water W1 decreases, it is not necessary to reduce the raw water pressure of the raw water W1 using a pressure reducing valve or the like. Increasing the discharge pressure of the pump 2 is reduced, and the power consumption of the pressurizing pump 2 can be reduced.
Thereby, the raw water pressure of the raw water W1 which distribute | circulates the raw | natural water line L1 can be used effectively, ensuring the differential pressure | voltage of the primary side and secondary side of the constant flow valve 5. FIG.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、流量フィードバック水量制御により透過水Ｗ２の流量を制御する。流量フィードバック水量制御で用いる速度形デジタルＰＩＤアルゴリズムでは、前回の操作量からの変化分を演算し、これに前回の操作量を加算して今回の操作量を求める方式であるため、第１検出流量値が離散値の場合でも、目標流量値との偏差を高速に解消することができる。そのため、温度変化や膜の閉塞等によりＲＯ膜モジュール４の水透過係数が急激に変化した場合でも、その変化に十分に追従することができる。従って、ＲＯ膜モジュール４の水透過係数が急激に変化した場合に、透過水Ｗ２の流量を目標流量値に短時間で収束させ、安定した水量の透過水Ｗ２を製造することができる。 Further, in the reverse osmosis membrane separation device 1 according to the present embodiment, the control unit 30 controls the flow rate of the permeate W2 by flow rate feedback water amount control. In the velocity type digital PID algorithm used in the flow rate feedback water amount control, the first detected flow rate is obtained by calculating a change from the previous manipulated variable and adding the previous manipulated variable to this to obtain the present manipulated variable. Even when the value is a discrete value, the deviation from the target flow rate value can be eliminated at high speed. Therefore, even when the water permeation coefficient of the RO membrane module 4 changes abruptly due to temperature change, membrane clogging, or the like, the change can be sufficiently followed. Therefore, when the water permeability coefficient of the RO membrane module 4 changes abruptly, the flow rate of the permeate water W2 can be converged to the target flow rate value in a short time, and the permeate water W2 having a stable water amount can be manufactured.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、圧力フィードバック水量制御により透過水Ｗ２の流量を制御する。この圧力フィードバック水量制御は、流量フィードバック水量制御のバックアップとして実行することができる。このため、流量フィードバック水量制御の実行中において、第１流量センサＦＭ１（図１参照）に故障が発生した場合でも、圧力フィードバック水量制御に切り換えることにより、安定した水量の透過水Ｗ４を製造することができる。 Further, in the reverse osmosis membrane separation device 1 according to this embodiment, the control unit 30 controls the flow rate of the permeated water W2 by pressure feedback water amount control. This pressure feedback water amount control can be executed as a backup of the flow rate feedback water amount control. Therefore, even when a failure occurs in the first flow sensor FM1 (see FIG. 1) during the flow rate feedback water amount control, the permeated water W4 having a stable water amount is manufactured by switching to the pressure feedback water amount control. Can do.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、温度フィードフォワード水量制御により透過水Ｗ２の流量を制御する。この温度フィードフォワード水量制御は、第１実施形態における流量フィードバック水量制御のバックアップとして実行することができる。このため、流量フィードバック水量制御の実行中において、第１流量センサＦＭ１（図１参照）に故障が発生した場合でも、温度フィードフォワード水量制御に切り換えることにより、安定した水量の透過水Ｗ２を製造することができる。 Further, in the reverse osmosis membrane separation device 1 according to the present embodiment, the control unit 30 controls the flow rate of the permeated water W2 by temperature feedforward water amount control. This temperature feedforward water amount control can be executed as a backup of the flow rate feedback water amount control in the first embodiment. Therefore, even when a failure occurs in the first flow sensor FM1 (see FIG. 1) during the execution of the flow rate feedback water amount control, the permeated water W2 having a stable water amount is manufactured by switching to the temperature feedforward water amount control. be able to.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、温度フィードフォワード回収率制御を実行する。このため、逆浸透膜分離装置１においては、透過水Ｗ２の回収率を最大としつつ、ＲＯ膜モジュール４におけるシリカ系スケールの析出をより確実に抑制することができる。 Further, in the reverse osmosis membrane separation device 1 according to the present embodiment, the control unit 30 executes temperature feedforward recovery rate control. For this reason, in the reverse osmosis membrane separation apparatus 1, precipitation of the silica scale in the RO membrane module 4 can be more reliably suppressed while maximizing the recovery rate of the permeated water W2.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、水質フィードフォワード回収率制御を実行する。このため、例えば、前段の硬水軟化装置からの硬度リーク量が増加した場合でも、逆浸透膜分離装置１においては、透過水Ｗ２の回収率を最大としつつ、ＲＯ膜モジュール４における炭酸カルシウム系スケールの析出をより確実に抑制することができる。 Moreover, in the reverse osmosis membrane separation device 1 according to the present embodiment, the control unit 30 executes water quality feedforward recovery rate control. For this reason, for example, even when the amount of hardness leak from the previous water softening device increases, the reverse osmosis membrane separation device 1 maximizes the recovery rate of the permeated water W2, and the calcium carbonate scale in the RO membrane module 4 Can be more reliably suppressed.
　また、本実施形態に係る逆浸透膜分離装置１においては、制御部３０は、水質フィードバック回収率制御を実行する。このため、逆浸透膜分離装置１においては、透過水Ｗ２に要求される水質を満たしつつ、透過水Ｗ２の回収率を最大限にまで高めることができる。 Further, in the reverse osmosis membrane separation device 1 according to the present embodiment, the control unit 30 executes water quality feedback recovery rate control. For this reason, in the reverse osmosis membrane separation apparatus 1, the recovery rate of the permeated water W2 can be maximized while satisfying the water quality required for the permeated water W2.
　以上、本発明の好ましい実施形態について説明した。しかし、本発明は、上述した実施形態に限定されることなく、種々の形態で実施することができる。
　例えば、前記実施形態では、各回収率制御において、排水比例制御弁８の弁開度を制御することにより、濃縮水Ｗ３の排水流量を調整する例について説明した。これに限らず、複数の排水バルブを並列に設けた構成とし、排水バルブの開弁数を増減することにより、濃縮水Ｗ３の残部Ｗ３２の排水流量を段階的に調整するように制御してもよい。これにより、濃縮水Ｗ３の残部Ｗ３２の排水流量を調整することができる。 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 above-described embodiment, the example in which the drainage flow rate of the concentrated water W3 is adjusted by controlling the valve opening degree of the drainage proportional control valve 8 in each recovery rate control has been described. Not limited to this, a configuration in which a plurality of drain valves are provided in parallel, and the drain flow rate of the remaining portion W32 of the concentrated water W3 can be controlled in stages by increasing or decreasing the number of drain valves opened. Good. Thereby, the waste_water | drain flow volume of the remainder W32 of the concentrated water W3 can be adjusted.
１　逆浸透膜分離装置
２　加圧ポンプ
４　ＲＯ膜モジュール（逆浸透膜モジュール）
５　定流量弁（定流量手段）
８　排水比例制御弁（比例制御弁、排水流量調整手段）
１４　原水比例制御弁（原水圧力調整手段）
３０　制御部（原水圧力制御部、加圧ポンプ駆動制御部、排水制御部、定流量差圧検出手段）
Ｊ２　合流部Ｌ１　原水ライン
Ｌ２　透過水ライン
Ｌ３　濃縮水ライン
Ｌ４　循環水ライン
Ｌ５　排水ライン
ＦＭ１　第１流量センサ（第１流量検出手段）
ＦＭ２　第２流量センサ（第２流量検出手段）
ＰＳ１　一次側圧力センサ（定流量差圧検出手段）
ＰＳ２　二次側圧力センサ（定流量差圧検出手段）
Ｗ１　原水
Ｗ２　透過水
Ｗ３　濃縮水
Ｗ３１　濃縮水の一部
Ｗ３２　濃縮水の残部 1 Reverse Osmosis Membrane Separator 2 Pressure Pump 4 RO Membrane Module (Reverse Osmosis Membrane Module)
5 Constant flow valve (constant flow means)
8 Wastewater proportional control valve (proportional control valve, wastewater flow rate adjusting means)
14 Raw water proportional control valve (Raw water pressure adjusting means)
30 control unit (raw water pressure control unit, pressure pump drive control unit, drainage control unit, constant flow rate differential pressure detection means)
J2 Junction L1 Raw water line L2 Permeated water line L3 Concentrated water line L4 Circulating water line L5 Drainage line FM1 First flow sensor (first flow detection means)
FM2 second flow rate sensor (second flow rate detection means)
PS1 Primary pressure sensor (Constant flow rate differential pressure detection means)
PS2 Secondary pressure sensor (Constant flow rate differential pressure detection means)
W1 Raw water W2 Permeated water W3 Concentrated water W31 Part of concentrated water W32 The remainder of concentrated water

Claims (4)

  1. 　原水を透過水と濃縮水とに分離する逆浸透膜モジュールと、
    　原水を前記逆浸透膜モジュールに供給する原水ラインと、
    　前記逆浸透膜モジュールで分離された透過水を送出する透過水ラインと、
    　前記逆浸透膜モジュールで分離された濃縮水を送出する濃縮水ラインと、
    　前記濃縮水ラインから分岐され、前記逆浸透膜モジュールで分離された濃縮水の一部を前記原水ラインの合流部に返送する循環水ラインと、
    　前記濃縮水ラインから分岐され、前記逆浸透膜モジュールで分離された濃縮水の残部を装置外へ排出する排水ラインと、
    　前記合流部よりも上流側の前記原水ラインに設けられ、前記合流部よりも上流側の前記原水ラインを流通する原水の圧力を調整する原水圧力調整手段と、
    　前記濃縮水ラインに設けられ、前記濃縮水ラインを流通する濃縮水の流量を所定の一定流量値に保持する定流量手段と、
    　前記定流量手段の一次側の圧力と二次側の圧力との差圧を検出差圧値として検出する定流量差圧検出手段と、
    　前記検出差圧値が所定の設定差圧以上になる範囲で原水の圧力が高くなるように、前記原水圧力調整手段を制御する原水圧力制御部と、を備える、逆浸透膜分離装置。     A reverse osmosis membrane module that separates raw water into permeate and concentrated water;
    A raw water line for supplying raw water to the reverse osmosis membrane module;
    A permeate line for delivering permeate separated by the reverse osmosis membrane module;
    A concentrated water line for delivering concentrated water separated by the reverse osmosis membrane module;
    A circulating water line that branches off from the concentrated water line and returns a part of the concentrated water separated by the reverse osmosis membrane module to a confluence portion of the raw water line;
    A drainage line that branches off from the concentrated water line and discharges the remainder of the concentrated water separated by the reverse osmosis membrane module to the outside of the device;
    Raw water pressure adjusting means that is provided in the raw water line upstream of the merging portion and adjusts the pressure of raw water flowing through the raw water line upstream of the merging portion;
    A constant flow rate means provided in the concentrated water line and holding a flow rate of the concentrated water flowing through the concentrated water line at a predetermined constant flow value;
    A constant flow rate differential pressure detecting means for detecting a differential pressure between a primary side pressure and a secondary side pressure as a detected differential pressure value;
    A reverse osmosis membrane separation device comprising: a raw water pressure control unit that controls the raw water pressure adjusting means so that the pressure of the raw water is increased in a range where the detected differential pressure value is equal to or higher than a predetermined set differential pressure.
  2. 　前記合流部よりも下流側の前記原水ラインに設けられ、原水を吸入して前記逆浸透膜モジュールに向けて吐出する加圧ポンプと、
    　透過水の流量を第１検出流量値として検出する第１流量検出手段と、
    　前記第１検出流量値が予め設定された目標流量値となるように、前記加圧ポンプの駆動を制御する加圧ポンプ駆動制御部と、を備える、
    請求項１に記載の逆浸透膜分離装置。     A pressure pump that is provided in the raw water line downstream from the merging portion, sucks raw water, and discharges the raw water toward the reverse osmosis membrane module;
    First flow rate detecting means for detecting the flow rate of the permeated water as a first detected flow rate value;
    A pressurization pump drive control unit that controls driving of the pressurization pump so that the first detection flow rate value becomes a preset target flow rate value,
    The reverse osmosis membrane separation apparatus according to claim 1.
  3. 　前記排水ラインに設けられ、装置外へ排出する濃縮水の排水流量を調整可能な排水流量調整手段と、
    　原水、透過水又は濃縮水の温度を検出温度値として検出する温度検出手段と、
    　前記排水流量調整手段を制御する排水制御部と、を備え、
    　前記排水制御部は、（ｉ）予め取得された原水のシリカ濃度、及び前記温度検出手段の検出温度値から決定したシリカ溶解度に基づいて、濃縮水におけるシリカの許容濃縮倍率を演算し、（ｉｉ）当該許容濃縮倍率の演算値、及び透過水の前記目標流量値から排水流量を演算し、（ｉｉｉ）濃縮水の実際排水流量が当該排水流量の演算値となるように、前記排水流量調整手段を制御する、
    請求項２に記載の逆浸透膜分離装置。     A drainage flow rate adjusting means provided in the drainage line and capable of adjusting the drainage flow rate of the concentrated water discharged outside the device,
    Temperature detecting means for detecting the temperature of raw water, permeated water or concentrated water as a detected temperature value;
    A drainage control unit for controlling the drainage flow rate adjusting means,
    The drainage control unit (i) calculates an allowable concentration ratio of silica in the concentrated water based on the silica concentration determined from the silica concentration of raw water obtained in advance and the detected temperature value of the temperature detecting means, and (ii) ) Calculating the drainage flow rate from the calculated value of the permissible concentration ratio and the target flow rate value of the permeated water, and (iii) adjusting the drainage flow rate so that the actual drainage flow rate of the concentrated water becomes the calculated value of the drainage flow rate. To control the
    The reverse osmosis membrane separation apparatus according to claim 2.
  4. 　濃縮水の排水流量を第２検出流量値として検出する第２流量検出手段を備え、
    　前記排水流量調整手段は比例制御弁からなり、
    　前記排水制御部は、前記第２検出流量値が前記排水流量の演算値となるように、前記比例制御弁の弁開度を調節する、
    請求項３に記載の逆浸透膜分離装置。     A second flow rate detecting means for detecting the drainage flow rate of the concentrated water as a second detected flow rate value;
    The drainage flow rate adjusting means comprises a proportional control valve,
    The drainage control unit adjusts a valve opening of the proportional control valve so that the second detected flow rate value is a calculated value of the drainage flow rate;
    The reverse osmosis membrane separation apparatus according to claim 3.
PCT/JP2017/005438 2016-06-13 2017-02-15 Reverse osmosis membrane separation apparatus WO2017217008A1 (en)

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