JP2008055336A - Operation method of permeation flux in membrane filtration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a judgment level of a permeation flux relating to an operation method of the permeation flux in a membrane filtration device. <P>SOLUTION: The operation method of the permeation flux in the membrane filtration device 8 is used for operating the permeation flux in a filtration processing part 12 by a membrane provided in a watering line 3 to equipment to be used, and performs sampling of data for operating the permeation flux at a timing stabilizing a filtration performance of the filtration processing part 12. Moreover, the filtration processing part 12 is constituted to perform flushing of the membrane at intervals, and the sampling of the data is performed after the lapse of a set time from the finishing of the flushing. Furthermore, data of water quality of treated water or waste water filtrated by the filtration processing part 12 measures, and the sampling of the data is performed at the timing stabilizing the measurement result. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for calculating a permeation flux in a membrane filtration device such as a water quality reforming system for reforming the quality of feed water supplied to a thermal apparatus such as a boiler.

  Researchers of the company of the applicant of the present application can improve the water quality by using a filtration member (liquid separation membrane (NF membrane)) that captures the corrosion promoting component in the feed water and leaves the corrosion inhibiting component in the feed water. A quality system (membrane filtration device) is proposed.

  In this water quality reforming system, there is a problem of clogging / deterioration of the filtration member (liquid separation membrane (NF membrane)). A water quality reforming system that contributes to corrosion prevention and accurate clogging / degradation determination has been proposed (see Patent Document 1).

JP 2005-288218 A

  In this patent document 1, it is stated that the permeation flux needs to be calculated in order to determine clogging / deterioration of the membrane. As a result of subsequent research and development, the inventors of this application have found that it is very important to improve the permeation flux determination level in order to put this seed membrane filtration device into practical use.

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to improve the determination level of a permeation | transmission flux.

  This invention was made in order to solve the said subject, The invention of Claim 1 is in the membrane filtration apparatus which calculates the permeation | transmission flux in the filtration process part by the membrane provided in the water supply line to a use apparatus. A permeation flux calculation method is characterized in that sampling of data for calculating a permeation flux is performed at a timing when the filtration performance of the filtration processing unit is stabilized.

  According to the first aspect of the present invention, since the sampling of the data is performed at a timing when the filtration performance is stable, the calculated permeation flux can be made highly reliable.

  According to a second aspect of the present invention, in the first aspect, the filtration processing unit is configured to perform flushing of the membrane at an interval, and the sampling of the data is performed after a set time has elapsed from the end of flushing. It is characterized by.

  According to the second aspect of the present invention, since sampling of data is performed in a state where the influence of flushing is small, the calculated permeation flux can be made highly reliable.

  The invention according to claim 3 is characterized in that, in claim 1, water quality data of the treated water or waste water filtered by the filtration processing unit is measured, and sampling of the data is performed at a timing when the measurement result is stabilized. It is a feature.

  According to the third aspect of the present invention, since the data is reliably detected and sampling is performed, the calculated permeation flux can be made highly reliable.

  According to a fourth aspect of the present invention, in the first to third aspects, the data is sampled a plurality of times, and the permeation flux is calculated by averaging the data of the plurality of times.

  According to the fourth aspect of the invention, since the data sampled a plurality of times are averaged, the influence of various disturbances can be reduced, so that the calculated permeation flux can be made more reliable.

  According to the present invention, the calculated permeation flux can be made highly reliable, and the permeation flux judgment level for judging clogging / deterioration of the membrane can be improved.

  An embodiment of the present invention will be described. The embodiment of the present invention can be suitably implemented in a membrane filtration apparatus using a filtration processing unit using a nanofiltration membrane (NF membrane, NF: Nanofiltration).

  An embodiment of the present invention is a method for calculating a permeation flux in a membrane filtration device that calculates a permeation flux in a filtration processing unit using a membrane provided in a water supply line to a device to be used. The sampling of the data is performed at a timing when the filtration performance of the filtration processing unit is stabilized.

  According to the embodiment of the present invention, sampling of data for calculating the permeation flux is performed at a timing when the filtration performance of the filtration processing unit is stabilized. As a result, the calculated permeation flux becomes highly reliable, and the determination level of clogging / deterioration of the film is improved.

  The used device is a device in which the treated water treated by the filtration processing unit is used, and is a boiler or the like.

  The membrane is preferably a nanofiltration membrane, but is not limited thereto, and can be, for example, an RO membrane. The membrane filtration device may be a filtration device having the filtration processing unit, and is not limited to a specific filtration device.

  The permeation flux is an index indicating the water permeation performance of the membrane, that is, the clogged state of the membrane, and the amount of water permeating the unit membrane area per unit time is converted to standard temperature conditions as per unit membrane differential pressure. Is. If this is expressed by an equation, it can be expressed by the following equation 1.

Permeation flux (L / m ² · h · MPa) = instantaneous flow rate of treated water / [{inlet operating pressure-(device differential pressure ÷ 2)-outlet back pressure-osmotic pressure} x temperature correction coefficient x membrane area] …… ............ Formula 1

Here, treated water instantaneous flow rate: detected value with treated water flow meter (unit: L / h), inlet operating pressure: detected value with inlet operating pressure sensor (unit: MPa), device differential pressure: set value (unit) : MPa), outlet back pressure: set value (unit: MPa), osmotic pressure: set value (unit: MPa), temperature correction coefficient: A (function of feed water temperature detected by feed water temperature sensor), membrane area: set Value (unit: m ² ).

Data for calculating the permeation flux (the instantaneous flow rate of treated water, the inlet operating pressure and the feed water temperature) is detected by each data measurement (detection) means, and the sampling of the data is performed by a control means such as a microcomputer. It is performed at a timing when the filtration performance of the filtration processing unit is stabilized. The device differential pressure, osmotic pressure, and outlet back pressure are not necessarily set values, and may be obtained by detecting in real time with a sensor.

  The timing at which the filtration performance of the filtration processing unit is stabilized means that the concentration inside the filtration processing unit has almost reached equilibrium. Specifically, the quality of the treated water, the quality of the drained water, the water temperature, the amount of drained water It means that the combination of any one or more is stable.

  Furthermore, in a membrane filtration apparatus configured to perform flushing of the membrane at an interval (first set time) as a specific aspect of a method for setting the timing at which the filtration performance of the filtration processing unit is stabilized, The sampling of the data is performed after a second set time has elapsed since the end of flushing.

  The flushing of the membrane is a method of causing pollutants to flow out by flowing a large amount of water (for example, raw water) along the membrane surface at a clean low pressure on the primary side of the membrane in order to eliminate or improve the clogging of the membrane. And can be carried out by a known method. This flushing is preferably configured to perform the next flushing every time the operation time of the membrane filtration device (filtration processing unit) reaches a first set time t1 (for example, 1 hour) after the previous flushing. The Thus, flushing is performed periodically.

  Immediately after the flushing, the permeability is good due to the influence of the osmotic pressure, and the permeability of the membrane is stabilized after the second set time t2. Accordingly, the data sampling is performed when the second set time t2 has elapsed after the flushing. By comprising in this way, the calculation of a permeation | transmission flux can be performed on the same conditions (conditions which the membrane performance was stabilized) as much as possible. Furthermore, since the internal concentration decreases due to the permeation phenomenon in accordance with the length of the time (from the time when the water flow is stopped to the time when the filtration processing unit is stopped (standby) until it is restarted), the second set time t2 Is preferably set according to the length of the processing stop time (when the stop time becomes longer, the second set time becomes longer).

  Further, as another specific aspect of the timing setting method in which the filtration performance of the filtration processing unit is stabilized, water quality data (for example, electrical conductivity) of treated water filtered by the filtration processing unit or drainage from the filtration processing unit Thus, the data can be sampled at a timing when the measurement result becomes stable. Here, the fact that the water quality is stable means that the water quality value is set in advance, and the data can be sampled when this water quality value is set.

  In this embodiment, the data sampling is preferably performed a plurality of times. By adopting such a configuration, since the permeation flux is calculated by averaging a plurality of data, the calculated permeation flux can be made more reliable.

  In an embodiment configured to perform flushing of the filtration processing unit at intervals, the number of times of sampling of the data is preferably an operation time per day of the filtration processing unit and an interval of the flushing. Set by. By adopting such a configuration, it is possible to appropriately and increase the number of samplings per day.

The present invention is not limited to the above-described embodiment. For example, an expression that expresses the permeation flux (L / m ² · h · MPa) is not limited to the expression 1, but the following expression 2 Can also be expressed.
Treated water instantaneous flow rate / [{(Inlet pressure−Outlet pressure) ÷ 2-Outlet back pressure−Osmotic pressure} × Temperature correction coefficient × Membrane area] …… Equation 2
Moreover, in the said Formula 1 or the said Formula 2, when the influence of an outlet back pressure or an osmotic pressure can be disregarded (constant), these can be deleted.

  Hereinafter, a first embodiment of a water quality reforming system using a membrane filtration apparatus in which the permeation flux calculation method of the present invention is implemented will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the first embodiment. FIG. 2 is a schematic configuration diagram of the membrane filtration device of the first embodiment. FIG. 3 is a main part control circuit diagram of the first embodiment. FIG. 4 is a flowchart for explaining the permeation flux calculation method of the first embodiment. FIG. 5 is a flowchart for explaining the alarm operation of the first embodiment.

  In FIG. 1, the water quality reforming system of the first embodiment indicated by reference numeral 1 is a system for reforming the quality of water supplied to the thermal equipment 2, and supplies water to the thermal equipment 2. It comprises a line 3, various devices 4 connected to the water supply line 3, and a water supply tank 5 that is connected to the water supply line 3 and stores water supplied to the thermal equipment 2. Although the various devices 4 are not particularly limited, the various devices 4 include an activated carbon filtering device 6, a soft water device 7, and a membrane filtering device (water quality reforming device) 8. A prefilter 10 is provided on the upstream side of the membrane filtration device 8.

  A treated water tank (not shown) stores treated water supplied from a water source such as tap water, industrial water, and groundwater. The water to be treated has its water quality modified by the water quality reforming system 1 of the present invention, and is supplied to the thermal equipment 2.

  The thermal equipment 2 is a steam boiler, a hot water boiler, a cooling tower, a water heater, or the like, and here, a multi-tube type once-through boiler called a water tube boiler will be described as an example. Although not specifically illustrated here, the boiler as an example of the thermal equipment 2 includes an annular lower header and an annular upper header that are arranged vertically at a predetermined interval, and a plurality of heat transfer tubes that are arranged between them. A combustion chamber defined by a plurality of heat transfer tubes, and a heating device such as a burner that is disposed above the combustion chambers and generates steam by heating the feed water in each heat transfer tube.

  A water supply line 3 from the water supply tank 5 is connected to the lower header. The lower header is provided with a discharge pipe for discharging (blowing) the concentrated water of the can water. The upper header is provided with a steam supply path for supplying the generated steam to a load device (not shown). The plurality of heat transfer tubes and the like are formed using a non-passivated metal.

  The activated carbon filtration device 6 is configured as a device for adsorbing and removing an oxidizing agent such as sodium hypochlorite dissolved in the water supply. The oxidant, that is, residual chlorine, may oxidize an ion exchange resin (not shown) of the soft water device 7 disposed on the downstream side of the activated carbon filtration device 6 to deteriorate the ion exchange capability at an early stage. Further, there is a possibility that the nanofiltration membrane (not shown), which will be described later, of the membrane filtration device 8 arranged further downstream is oxidized to deteriorate the filtration capability at an early stage. Therefore, in order to prevent such early deterioration of capacity due to oxidation, the residual chlorine is adsorbed and removed by activated carbon, thereby preventing the early deterioration of the ion exchange capacity and the early deterioration of the filtration capacity. In addition, the water treatment efficiency is improved and stabilized.

  The soft water device 7 is configured as a device that removes hardness components such as calcium and magnesium contained in the water supply from which the residual chlorine has been removed with an ion exchange resin (not shown). That is, the soft water device 7 is configured as a device for replacing various hardness components contained in the water supply with sodium ions to convert the water into soft water. The pre-filter 10 is for removing dust and the like from the water supply.

2 and 3, the membrane filtration device 8 is connected to a filtration processing unit 12, a pump 13 connected to the upstream side of the filtration processing unit 12, and an upstream side and a downstream side of the filtration processing unit 12. Various measuring instruments 14a to 14e, an inverter 15 connected to the pump 13, control of the pump 13, determination of clogging / deterioration of the filtration member of the filtration processing unit 12, and control of the entire apparatus, And a control unit 16 that controls the reporting means 18 that displays a clogging / deterioration alarm by display. Hereafter, each said structure is demonstrated.

  The filtration processing unit 12 includes a filtering member, and specifically includes a nanofiltration membrane (NF membrane, NF: Nanofiltration) described in Patent Document 1.

  The water supply sent out from the pump 13 flows into one end of the filtration unit 12. In the inflowing water supply, the corrosion promoting component is captured and the corrosion inhibiting component is permeated by the nanofiltration membrane inside the filtration unit 12. From the other end of the filtration unit 12, permeated water and concentrated water flow out. The permeated water flows through the water supply line 3 and is stored in the water supply tank 5. On the other hand, a part of the concentrated water flows toward the drainage line 11 and the rest flows through the circulating water line 17 and is supplied to the upstream side of the pump 13.

Here, the said corrosion acceleration | stimulation component and the said corrosion suppression component are demonstrated. First, the corrosion promoting component is a portion where corrosion of each of the heat transfer tubes (not shown) of the boiler as an example of the thermal device 2 is likely to occur, in particular, moisture (canned water here) adheres to the inside, and This refers to the one that acts on the inner surface of each heat transfer tube (not shown) heated from the outside and promotes its corrosion. Usually, sulfate ions (SO ₄ ²⁻ ), chloride ions (Cl ⁻ ), and other components Is included. Incidentally, both sulfate ions and chloride ions are important as corrosion promoting components. Next, the corrosion inhibiting component, which is a component that inhibits corrosion, acts on a portion where the corrosion of each of the heat transfer tubes (not shown) of the boiler easily occurs, in particular, on the inner surface of each heat transfer tube (not shown), It means what can suppress the corrosion that occurs there, and usually contains silica (ie, silicon dioxide (SiO ₂ )).

  Returning to the description of the configuration of the membrane filtration device 8. The pump 13 is for supplying the filtration processing unit 12 with water from which dust or the like flowing through the water supply line 3 on the downstream side of the prefill 10 is removed. It is configured to vary according to the output frequency output from the connected inverter 14 (constant flow control is performed).

  The various measuring devices 14 include a flow sensor 14a, a temperature sensor 14b, an inlet pressure sensor 14c, an outlet pressure sensor 14d, and an electric conductivity meter 14e. The flow rate sensor 14 a detects the amount of permeated water that has passed through the filtration processing unit 12 and outputs a flow rate detection signal to the control unit 16, and the water supply line 3 on the downstream side of the filtration processing unit 12. It is connected to the.

  The temperature sensor 14b is connected to one of the water supply line 3 on the upstream side of the filtration processing unit 12, the water supply line 3 on the downstream side of the filtration processing unit 12, and the drainage line 11. In Example 1, It is connected to the water supply line 3 upstream of the filtration unit 12 and upstream of the pump 13. The temperature sensor 14 b is configured to detect the temperature of the water supply and output a temperature detection signal to the control unit 16.

  The inlet operation pressure sensor 14c and the outlet back pressure sensor 14d are connected to the water supply line 3 upstream and downstream of the filtration processing unit 12, respectively, and detect the pressure of the water supply and send a pressure detection signal to the control unit 16. It is configured to output to.

The electrical conductivity meter 14e is connected to the water supply line 3 on the downstream side of the filtration processing unit 12 and detects the electrical conductivity of the permeated water that has passed through the filtration processing unit 12, and sends the detection signal to the control unit 1
6 is configured to output to 6.

  The control procedure of the control unit 16 includes a first control procedure shown in FIG. 4 for inputting signals from the various measuring devices 14 and calculating a permeation flux that is a characteristic part of the present invention, and a calculated permeation flow. It includes the second control procedure shown in FIG. 5 that warns of clogging / degradation of the film based on the bundle.

The permeation flux (L / m ² · h · MPa) is calculated by the following equation 1.
Treated water instantaneous flow rate / [{inlet operating pressure− (device differential pressure ÷ 2) −outlet back pressure−osmotic pressure} × temperature correction coefficient × membrane area] ………… Equation 1

Here, “the instantaneous treated water flow rate” is a detected value (unit: L / h) at the flow rate sensor 14a, and “inlet operating pressure” is a detected value (unit: MPa) at the inlet operating force sensor 14c. “Device differential pressure” is a set value (unit: MPa), “Outlet back pressure” is a set value (unit: MPa), and “Osmotic pressure” is a set value (unit: MPa). Temperature correction coefficient: A (function of feed water temperature detected by the temperature sensor 14b), membrane area: set value (unit: m ² ), and the “osmotic pressure” is applied to the drain line 11 It can also obtain | require indirectly from the detected value of the provided electrical conductivity meter (illustration omitted). The “apparatus differential pressure” can be obtained from the difference between the detected value of the inlet pressure sensor 14 c and the detected value of a pressure sensor (not shown) provided in the drainage line 11.

  In the first embodiment, the filtration processing unit 12 performs membrane flushing. The flushing is configured to perform the next flushing every time the operation time of the membrane filtration device (filtration processing unit) reaches a first set time t1 (for example, 1 hour) after the previous flushing. Yes.

  And it is comprised so that the sampling of the data required for the calculation of permeation flux may be performed after the second set time t2 (for example, about 10 minutes) has elapsed since the end of flushing. Further, if the permeation flux measured per flushing (every hour of operation time) is counted 10 times, the average value is held as the average permeation flux. Therefore, if the user operates the membrane filtration device 8 for about 10 hours per day, the permeation flux can be obtained once a day. The data sampling and the permeation flux calculation of the first embodiment are performed based on the control procedure of FIG.

Next, the operation of the first embodiment will be described below.
(Overall operation)
When the thermal device 2 is operated, water is generated by reforming the quality of water to be treated (water before quality reforming) supplied from a water tank to be treated (not shown), and the water is supplied to the water tank. 5 need to be stored. The process up to this point will be described. The feed water flowing through the feed water line 3 flows out from the treated water tank (not shown) at a predetermined pressure by a feed water pump (not shown) having a predetermined discharge pressure. The pressure of the flowing water supply is set in consideration of pressure loss and the like in the various devices 4 arranged on the downstream side. And the feed water which flowed out from the to-be-processed water tank which is not illustrated first passes the said activated carbon filtration apparatus 6, and turns into a feed water of the state from which the residual chlorine was removed. Next, the water supply passes through the water softening device 7 and becomes soft water.

Subsequently, the water supply, which is soft water, is subjected to a filtration process in the membrane filtration device 8 and becomes water supply that can be supplied to the thermal equipment 2. Specifically, when water supply which is soft water passes through the nanofiltration membrane in the filtration unit 12 of the membrane filtration device 8, corrosion promoting components such as sulfate ions and chloride ions are captured by the nanofiltration membrane. . That is, the corrosion promoting component is removed from the soft water. On the other hand, the silica contained in the soft water, that is, the corrosion-inhibiting component, passes through the nanofiltration membrane together with the soft water. The feed water that becomes soft water containing the corrosion inhibiting component after the filtration treatment is stored in the feed water tank 5 as feed water that can be supplied to the thermal equipment 2.

  The water supply stored in the water supply tank 5 is supplied to the heat equipment 2 via a water supply pump (not shown) disposed between the water supply tank 5 and the heat equipment 2, and is supplied as can water in the lower header. Stored. The stored can water rises in each heat transfer tube while being heated by the heating device, and gradually becomes steam. And the steam produced | generated in each heat exchanger tube is collected in an upper header, and is supplied to a load apparatus from a steam supply path.

  By the way, during the operation of the thermal device 2, each heat transfer tube has its lower end portion, that is, the connection portion with the lower header, continuously in contact with the can water. Therefore, each heat transfer tube is likely to be corroded under the influence of can water at the lower end portion. In particular, each heat transfer tube is liable to cause local corrosion in addition to thinning corrosion on the inner peripheral surface at the lower end portion, and may cause breakage due to minute holes.

  The local corrosion is a hole-like corrosion from the contact surface side of each heat transfer tube with the can water toward the opposite side of the thickness direction, that is, a hole shape generated in the thickness (thickness) direction of each heat transfer tube. Say no corrosion. Hereinafter, such a local corrosion occurrence phenomenon is referred to as “pitting corrosion”, and pitting corrosion caused by this pitting corrosion is referred to as “corrosion”. Incidentally, it is understood that pitting corrosion usually occurs due to the influence of dissolved oxygen in the can water.

  However, according to the first embodiment, during the operation of the thermal equipment 2, since the soft water containing the corrosion inhibiting component is supplied as can water to each heat transfer tube, the corrosion inhibition contained in the can water is suppressed. The component acts on the lower end portion of each heat transfer tube to suppress corrosion of the portion. More specifically, the corrosion-inhibiting component suppresses thinning corrosion at the contact portion of each heat transfer tube with the can water, and also suppresses the generation and growth of pits. Suppresses damage to heat tubes. At this time, since the corrosion promoting component is removed from the can water by the membrane filtration device 8, the corrosion inhibiting action as described above by the corrosion inhibiting component is hardly inhibited by the corrosion promoting component and seems to be effectively exhibited. become.

  Now, corrosion of each heat transfer tube is suppressed by the corrosion-inhibiting component contained in the can water, and it is eluted from each heat transfer tube due to the influence of dissolved oxygen, etc. (corrosion promoting component of each heat transfer tube) contained in the can water. This is probably because a corrosion-inhibiting component (particularly silica) acts on the component to form a corrosion-resistant film (corrosion-resistant film) on the inner surface of each heat transfer tube. In particular, dissolved oxygen may cause a local anode to appear in each heat transfer tube, thereby causing pitting corrosion, but the corrosion inhibiting component (silica) contained in the can water is an anion or a negatively charged micelle. Since it exists, it is easy to adsorb | suck to the above anodes, and it is easy to selectively form an anticorrosion film in the said part. Therefore, it is considered that the corrosion inhibiting component (silica) contained in the can water can effectively suppress the progress of pitting corrosion in each heat transfer tube.

(Calculation of permeation flux)
Next, the calculation method of the permeation flux according to the first embodiment will be described with reference to FIG. In processing step S1 (hereinafter, processing step SN is simply referred to as SN), it is determined whether or not the number of samplings since the end of the previous calculation of permeation flux is the set number (10 times). This determination is made by comparing the count value (initial setting zero) of the sampling number counter (not shown) with the set number of times.

If the determination in S1 is NO, it is determined in S2 whether or not the first set time t1 has elapsed since the previous flushing. If NO at S2, the process stops at S2, and if YES is determined, the process proceeds to S3 to determine whether or not the second set time t2 has elapsed since the end of flushing. If NO in S3, the process stops in S3. If YES is determined, the process proceeds to S4, where data sampling is performed, and the sampling value is stored in a memory (not shown) for each sampling. The sampled data is data necessary for the calculation of Equation 1. Next, in S5, the value of the sampling number counter is incremented by 1, and the process returns to S1.

  The above-described processes of S1 to S5 are repeated, and if YES is determined in S1, the process proceeds to S6, the sampling number counter is reset in S6, and each data sampled in S4 is sampled a set number of times in S7. And the average permeation flux is calculated based on Equation (1). Then, the value is displayed on the notification means 18 for notification.

(Clogging / deterioration warning of membrane)
Next, the operation of the alarm for clogging / deterioration of the membrane using the calculated permeation flux will be described. Referring to FIG. 5, in S11, it is determined whether or not the calculated permeation flux is equal to or less than a set value. The set value may be a ratio to the initial permeation flux. The set value can be different between clogging and degradation. For example, clogging is average permeation flux / initial permeation flux = 80%, and degradation is average permeation flux / initial permeation flux. = 120%.

  If the determination in S11 is NO, the process returns to S11, and if the determination is YES, the clogging / degradation of the film is displayed on the notification means 18 and an alarm is given. This alarm can be performed using sounds other than the display. By the notification by the notification means 18, the system administrator can perform maintenance and inspection of the membrane filtration processing unit 12.

  According to the first embodiment, since the calculation of the permeation flux is performed at a timing when the membrane performance after flushing is stabilized, the reliability of the permeation flux can be improved. Further, since the permeation flux is configured to average a large number of data, the permeation flux reliability can be further improved.

  It goes without saying that the present invention can be variously modified without departing from the spirit of the present invention. For example, in the first embodiment, only the sampling and storage of data is performed at S4, and the permeation flux is calculated at S7. It is possible to store the values and calculate the average permeation flux by averaging the permeation fluxes stored in S7.

It is a schematic block diagram of Example 1 of the water quality modification system which implemented this invention. It is a schematic block diagram of the membrane filtration apparatus of FIG. It is explanatory drawing of the control circuit of the Example 1. FIG. It is a flowchart explaining the calculation method of the permeation | transmission flux of the Example 1. FIG. It is a flowchart explaining the alarm operation | movement of the Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water quality reforming system 2 Thermal equipment 3 Water supply line 4 Various apparatuses 5 Water supply tank 6 Activated carbon filtration apparatus 7 Soft water apparatus 8 Membrane filtration apparatus 10 Prefilter 11 Drainage line 12 Filtration processing part 13 Pump 14 Various measuring instruments 14a Flow rate sensor 14b Temperature sensor 14c Inlet pressure sensor 14d Outlet back pressure sensor 14e Electrical conductivity meter 15 Inverter 16 Control unit 17 Circulating water line 18 Notification means

Claims (4)

A method for calculating a permeation flux in a membrane filtration device for calculating a permeation flux in a filtration processing section by a membrane provided in a water supply line to a device used,
A method for calculating a permeation flux in a membrane filtration device, wherein sampling of data for calculating a permeation flux is performed at a timing when the filtration performance of the filtration processing unit is stabilized.   The membrane filtration device according to claim 1, wherein the filtration processing unit is configured to perform flushing of the membrane at an interval, and the sampling of the data is performed after a set time has elapsed from the end of flushing. Calculation method of permeation flux in   The permeation in the membrane filtration device according to claim 1, wherein water quality data of treated water or waste water filtered by the filtration processing unit is measured, and sampling of the data is performed at a timing when the measurement result is stabilized. Flux calculation method.   4. The membrane filtration device according to claim 1, wherein the sampling of the data is performed a plurality of times, and the permeation flux is calculated by averaging the plurality of times of data. Calculation method of permeation flux.

Images