JP7351644B2 - Membrane separation device performance diagnosis method and membrane separation device - Google Patents

Description

The present invention relates to a method for diagnosing the performance of a membrane separation device and a membrane separation device.

As a performance diagnosis method for separation membranes such as reverse osmosis membranes and ultrafiltration membranes in operation, the operating status data (flow rate of permeated water and concentrated water, There is a known method for determining whether or not a membrane module in a membrane module unit is blocked based on pressure loss, etc. (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 7-144120

When a specific membrane module in a membrane module unit becomes clogged, it is preferable to clean or replace only that membrane module from the viewpoint of cost. However, with the above-described method, it is not possible to specify which membrane module is blocked, and therefore the entire unit including membrane modules that are not blocked may have to be cleaned or replaced. In order to individually determine the presence or absence of blockage, it is conceivable to install a flow meter or pressure gauge for each membrane module, but in actual equipment, there is currently no space for such installation. Furthermore, if a flow meter or a pressure gauge is installed in each membrane module, significant improvements to the equipment will be required, which will incur a great deal of cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a performance diagnosis method for a membrane separation device and a membrane separation device that can individually determine whether or not a separation membrane is clogged without separately installing a flow meter or a pressure gauge. .

In order to achieve the above object, a method for diagnosing the performance of a membrane separation device according to one aspect of the present invention includes determining which separation membrane is blocked among a plurality of separation membranes, each of which separates raw water into permeated water and concentrated water. A method for diagnosing the performance of a membrane separation device to identify the A process of distributing permeated water through a permeated water line, a process of obtaining time changes in the surface temperature of piping that constitutes the permeated water line while hot water is flowing through the permeated water line, and a process of obtaining the obtained time changes . a step of determining the presence or absence of occlusion of a predetermined separation membrane based on the above, and the step of determining the presence or absence of occlusion is based on the step of determining the presence or absence of occlusion of a predetermined separation membrane based on the obtained time change. Determining whether or not a given separation membrane is occluded based on the time change or whether the time change is slower than the time change obtained for another separation membrane that is not occluded. There is.

In addition, a method for diagnosing the performance of a membrane separation device according to another aspect of the present invention includes a method for diagnosing the performance of a membrane separation device , each of which uses a membrane for identifying which separation membrane is clogged among a plurality of separation membranes that separate raw water into permeated water and concentrated water. A method for diagnosing the performance of a separation device , which includes the steps of externally heating piping constituting a permeate line through which permeated water from a predetermined separation membrane among a plurality of separation membranes flows ; and after heating the piping, a predetermined The process of supplying raw water to a predetermined separation membrane through the raw water line that supplies raw water to the separation membrane and distributing it to the permeate line, and while the raw water is flowing through the permeate line, the piping that makes up the permeate line. The process includes a step of acquiring a temporal change in surface temperature , and a step of determining whether or not a predetermined separation membrane is clogged based on the acquired temporal change . is more gradual than the time change obtained when a given separation membrane is not occluded or the time change obtained for another separation membrane that is not occluded. including determining whether the membrane is occluded .

Further, the membrane separation device according to one aspect of the present invention includes a plurality of separation membranes each of which separates raw water into permeated water and concentrated water, a plurality of raw water lines that supply raw water to the plurality of separation membranes, and a plurality of separation membranes. A plurality of permeated water lines that circulate permeated water from The acquisition method includes an acquisition means for acquiring temperature information of piping, and a determination means for identifying which separation membrane among the plurality of separation membranes is blocked based on the temperature information acquired by the acquisition means. The means includes, while the hot water supplied to a predetermined separation membrane among the plurality of separation membranes is flowing through a permeate line through which permeated water from the predetermined separation membrane flows, the piping constituting the permeated water line. The determination means obtains a time change in surface temperature, and determines whether the time change obtained by the obtaining means is a time change obtained when a predetermined separation membrane is not clogged, or a time change obtained when a predetermined separation membrane is not clogged. It is determined whether a predetermined separation membrane is clogged or not based on whether the change over time is slower than the time change obtained for .

Further, a membrane separation device according to another aspect of the present invention includes a plurality of separation membranes, each of which separates raw water into permeated water and concentrated water, a plurality of raw water lines that supply raw water to the plurality of separation membranes, and a plurality of separation membranes. A plurality of permeated water lines through which permeated water flows through the membrane, a heating means for externally heating a plurality of piping constituting the plurality of permeated water lines, an acquisition means for acquiring temperature information of the plurality of piping , and an acquisition means. determination means for identifying which separation membrane among the plurality of separation membranes is blocked based on the temperature information acquired by the means; After the raw water is supplied to a predetermined separation membrane among the plurality of separation membranes, while the raw water is flowing through the permeate line that distributes the permeate water from the predetermined separation membrane, the piping that makes up the permeate line The determining means determines whether the time change obtained by the obtaining means is a time change obtained when the predetermined separation membrane is not clogged, or a time change obtained when the predetermined separation membrane is not clogged. It is determined whether a predetermined separation membrane is clogged based on whether the change over time is slower than that obtained for the membrane.

According to such a performance diagnosis method and membrane separation device , the presence or absence of blockage of the separation membrane is determined based on the temperature information of the piping, so even if there are multiple separation membranes, the flow meter and pressure There is no need to install a meter. Furthermore, means for acquiring temperature information on piping (thermography, thermocouples, etc.) can be easily added to existing equipment, and there is no need to significantly improve the equipment.

As described above, according to the present invention, it is possible to individually determine whether or not a separation membrane is clogged without separately installing a flow meter or a pressure gauge.

1 is a schematic diagram showing the configuration of a membrane separation device according to a first embodiment of the present invention. 1 is a schematic diagram showing an example of the configuration of a membrane module unit to which the present invention can be applied. FIG. 2 is a schematic diagram showing the configuration of a membrane separation device according to a second embodiment of the present invention.

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

(First embodiment)
FIG. 1(a) is a schematic diagram showing the configuration of a membrane separation device according to a first embodiment of the present invention, and FIG. 1(b) is a membrane module constituting the membrane separation device of FIG. 1(a). FIG. 2 is a schematic diagram showing the configuration of a unit.

The membrane separation device 1 has a raw water tank 2 and a membrane module unit 3, and the raw water supplied from the raw water tank 2 (well water, river water, lake water, tap water, ground water, or obtained by primary treatment of these) The membrane module unit 3 removes impurities in the primary pure water (primary pure water, etc.) to generate permeated water (treated water). The membrane module unit 3 is composed of a plurality of membrane modules 31 and 32 connected in parallel. Each membrane module 31, 32 includes a cross-flow type separation membrane 31a, 32a that separates raw water supplied parallel to the membrane surface into concentrated water containing impurities and permeated water from which impurities have been removed. The separation membranes 31a and 32a include reverse osmosis membranes (RO membranes), nanofiltration membranes (NF membranes), ultrafiltration membranes (UF membranes), microfiltration membranes (MF membranes), and ion exchange for electrodesalination/concentration. membranes, or degassing membranes are used.

The membrane module unit 3 includes a raw water line L1 that supplies raw water to the membrane module unit 3, a permeated water line L2 that circulates permeated water from the membrane module unit 3 and supplies it to a treated water tank or a use point, and a membrane module. A concentrated water line L3 through which concentrated water from the unit 3 flows and is discharged to the outside is connected. The raw water line L1 branches into two raw water branch lines L11 and L12, which are connected to the primary sides of the separation membranes 31a and 32a, respectively, on the upstream side in the water flow direction in the cross-flow system. Two permeated water branch lines L21 and L22 are connected to the secondary sides of the separation membranes 31a and 32a, respectively, and these are merged into one permeated water line L2. Two concentrated water branch lines L31 and L32 are respectively connected to the downstream side of the primary side of the separation membranes 31a and 32a in the water flow direction in the cross-flow method, and these are merged into one concentrated water line L3. becomes.

The raw water line L1 is provided with a pressure pump 4 for supplying the raw water stored in the raw water tank 2 to the membrane module unit 3, and on the downstream side thereof, the pump 4 adjusts the flow rate of raw water supplied to the membrane module 3. Therefore, a flow rate adjustment valve (not shown) whose opening degree can be adjusted is provided. The raw water line L1 is provided with a valve V1 used in a performance diagnosis process described later. Note that a raw water supply line (not shown) is connected to the raw water tank 2, and raw water is supplied as needed. Further, the permeated water line L2 and the concentrated water line L3 are respectively provided with flow meters 5 and 6 that detect the flow rates of the permeated water and concentrated water.

Furthermore, the membrane separation apparatus 1 is provided with a plurality of pressure sensors (not shown) for detecting the operating state of the membrane module unit 3 (pressure loss of permeated water, concentrated water, etc.). As a result, not only the operating state data of the membrane module unit 3 can be obtained, but also it is possible to determine whether or not the membrane modules 31 and 32 in the membrane module unit 3 are blocked based on the operating state data. become. However, it is not possible to specify which membrane module 31 or 32 is blocked using only the operating status data of the membrane module unit 3, and therefore it is difficult to clean or replace only the blocked membrane module. It is. On the other hand, if the operating status of each membrane module 31, 32 (for example, the flow rate of permeated water and concentrated water) can be detected (measured), the presence or absence of blockage can be determined individually, but the installation space for the flowmeter is In addition to this problem, major improvements to the equipment are also required.

Therefore, in this embodiment, when it is found that the membrane modules 31 and 32 are blocked based on the above-mentioned operating state data, a performance diagnosis step is performed to identify which membrane module 31 or 32 is blocked. will be held. Specifically, a performance diagnosis step is performed in which hot water is passed through the membrane modules 31 and 32 (separation membranes 31a and 32a) to determine the presence or absence of blockage. As a configuration for this purpose, the membrane separation apparatus 1 of this embodiment includes a heat exchanger 7, a thermograph 8, and a control section 10.

The heat exchanger 7 is provided in the bypass line L4 connected to the raw water line L1, and heats the raw water supplied to the membrane module unit 3 through the raw water line L1 to produce hot water (for example, water at about 40 to 50°C). It functions as a heating means to generate. Bypass line L4 is connected to raw water line L1 via valves V2 and V3 so as to bypass valve V1 of raw water line L1. The thermograph 8 has a function of acquiring temperature information of the membrane modules 31 and 32, specifically, temperature information of each piping that constitutes the permeated water branch lines L21 and L22 of each membrane module 31 and 32. In addition to the function of controlling the operation of the membrane separation device 1, the control unit 10 also has the function of controlling the operation of the membrane separation device 1, and also has the function of controlling the operation of the membrane separation device 1. It also has a function as a determining means for individually determining whether or not the membrane modules 31 and 32 (separation membranes 31a and 32a) are clogged based on the temperature information.

The performance diagnosis process in the membrane separation device 1 of this embodiment is performed in parallel with the normal operation (water sampling operation) of the membrane separation device 1. When the performance diagnosis process is started, valves V2 and V3 of the bypass line L4 are opened, and at the same time as the heat exchanger 7 is activated, the valve V1 of the raw water line L1 is closed. Thereby, hot water is supplied from the bypass line L4 to the membrane modules 31 and 32 through the raw water branch lines L11 and L12. Then, a part of it passes through the separation membranes 31a and 32a and flows into permeate branch lines L21 and L22, and is supplied from the permeate line L2 to the treated water tank or use point, and the rest is concentrated water branch line L31, It flows through L32 and is discharged to the outside through the concentrated water line L3. In addition, when hot water is supplied to a use point as permeated water, the temperature of the hot water is set according to the maximum temperature allowed there.

At this time, in the permeated water branch lines L21 and L22, the temperature of the piping constituting each line increases due to the hot water flowing inside, and heat is radiated from the surface thereof. This radiant heat is photographed as a thermal image by a thermography 8, and temperature information of each pipe, specifically, information regarding temporal changes in surface temperature, is obtained from the photographed thermal image.

It is thought that the surface temperature of the pipe changes depending on the flow rate of hot water flowing through the pipe, and the flow rate changes depending on the degree of occlusion of the membrane module. That is, in a membrane module with a greater degree of blockage, the flow rate flowing through the connected piping becomes smaller, and the surface temperature of the piping rises more slowly accordingly. Therefore, if one of the membrane modules 31, 32 is blocked, a difference will occur in the flow rate of hot water flowing through the permeate branch lines L21, L22, and as a result, the permeate branch lines L21, L22 will Differences also occur in the changes in surface temperature of the constituent piping over time. Therefore, by checking such a difference based on the information acquired by the thermography 8, it is possible to specify which of the membrane modules 31 and 32 is blocked. In other words, which of the membrane modules 31 and 32 is blocked can be specified depending on which of the pipes forming the permeated water branch lines L21 and L22 has a more gradual rise in surface temperature.

On the other hand, when both membrane modules 31 and 32 are blocked, there is almost no difference in the surface temperature changes over time of the pipes forming the permeated water branch lines L21 and L22. Therefore, it is not possible to clearly determine whether or not the membrane modules 31 and 32 are clogged by simply comparing the time changes in the surface temperatures of the two pipes that make up the permeated water branch lines L21 and L22 or the concentrated water branch lines L31 and L32. It is difficult. In such a case, it is necessary to individually determine whether or not the membrane modules 31 and 32 are clogged based on comparison with initial temperature information obtained when the membrane modules 31 and 32 are not clogged. I can do it. In other words, if the surface temperature of the pipe rises more slowly than when it is not clogged, or if the surface temperature of the pipe changes over time, it is possible to calculate the flow rate of hot water flowing through the pipe. If the flow rate calculated in this way is smaller than the initial flow rate when the pipe is not clogged, it can be determined that the membrane module connected to the pipe is clogged.

In addition to the piping that constitutes the permeated water branch lines L21 and L22, the piping that constitutes the concentrated water branch lines L31 and L32 was also photographed using the thermography 8, and the primary side of the membrane modules 31 and 32 (raw water and concentrated water It may also be possible to check the blockage state on the distribution side). Thereby, it is possible to estimate the raw water inflow rate, recovery rate, concentration level, etc. of each membrane module 31, 32.

When the clogged membrane module is identified, the supply of hot water to the membrane module unit 3 is stopped, and the performance diagnosis process is completed. Specifically, the heat exchanger 7 is stopped, the valves V2 and V3 of the bypass line L4 are closed, and the performance diagnosis process is completed. When the performance diagnosis step is completed, the blocked membrane module is cleaned or replaced as necessary. In that case, the operation of the membrane separator 1 is stopped, but as will be described later, if there is no need to clean or replace the membrane module, the valve V1 of the raw water line L1 is opened when the performance diagnosis step is completed. , water sampling operation will continue.

As described above, according to the performance diagnosis process of the present embodiment, it is possible to determine whether or not the membrane modules 31 and 32 (separation membranes 31a and 32a) are clogged based on the temperature information of the pipes connected to the membrane modules 31 and 32. be done. Therefore, it is not necessary to provide detection means such as a flow meter or a pressure gauge for detecting the operating state of each membrane module 31, 32. In addition, thermography 8 is used as an acquisition means for acquiring temperature information of piping, but thermography 8 can be easily added to existing equipment, and its installation requires major improvements to the equipment. There is no need to do anything, and there are no extra costs.

In this embodiment, hot water is used to diagnose the performance of the membrane modules 31 and 32 (separation membranes 31a and 32a). ) can be said to have a certain level of dissolving power. Therefore, the hot water supplied to the primary side of the membrane modules 31 and 32 and flowing parallel to the membrane surfaces of the separation membranes 31a and 32a is discharged to the outside through the concentrated water line L3 while dissolving and taking in the dirt attached thereto. That will happen. Therefore, the performance diagnosis step of this embodiment using hot water is also advantageous in that a cleaning effect on the separation membranes 31a and 32a can be obtained as a secondary effect. From this point of view, even after a blocked membrane module is identified in the performance diagnosis process, hot water is continuously supplied to the membrane module unit 3 in order to clean the blocked membrane module. Good too. However, if the degree of blockage is large, normal operation of the membrane separator 1 may be stopped, and the blocked membrane module may be cleaned with a chemical solution or replaced if necessary.

The performance diagnosis step of this embodiment is carried out when it is found that the membrane modules 31 and 32 are blocked based on the operating state data of the membrane module unit 3, but the timing of the execution is limited to this. It's not a thing. For example, during a test run after installation of the membrane separation device 1, it may be carried out to determine whether the membrane modules 31, 32 are functioning normally, or to predict whether the membrane modules 31, 32 are clogged. Alternatively, it may be carried out periodically during normal operation. Further, after a clogged membrane module has been identified and the membrane module has been cleaned, it may be carried out in order to confirm the effect. In this way, even if the performance diagnosis step is completed, if there is no need to clean or replace the membrane module, the water sampling operation continues without stopping the operation of the membrane separator 1.

In addition, in the performance diagnosis process of this embodiment, as mentioned above, in addition to the pipes that make up the permeated water branch lines L21 and L22, temperature information of the pipes that make up the concentrated water branch lines L31 and L32 is also obtained. It is also possible to calculate the recovery rate (ratio of the flow rate of permeated water to the sum of the flow rate of permeated water and the flow rate of concentrated water) of each membrane module 31, 32. Therefore, the performance diagnosis process of this embodiment is performed periodically during the normal operation of the membrane separation apparatus 1 in order to determine whether the actual recovery rate of each membrane module 31, 32 deviates from the set value. It may also be carried out. In addition, when carrying out the performance diagnosis step of this embodiment for such a purpose, as shown in the figure, flow control valves V21, V22, V22, It is preferable that V31 and V32 are provided. As a result, even if the actual recovery rate deviates from the set value, the recovery rate of each membrane module 31, 32 can be adjusted to the optimal value by adjusting the flow rate adjustment valves V21, V22, V31, and V32. I can do it. For example, when the actual recovery rate of the membrane module 31 exceeds the set value, the flow rate of the permeated water flowing through the permeated water branch line L21 is reduced by throttling the flow rate control valve V21, thereby lowering the recovery rate. Can be done. Furthermore, when the actual recovery rate of the membrane module 31 is lower than the set value, the flow rate of concentrated water flowing through the concentrated water branch line L31 is reduced by throttling the flow rate control valve V31, thereby increasing the recovery rate. Can be done. Note that the opening degrees of the flow rate regulating valves V21, V22, V31, and V32 are normally performed manually, but may be performed automatically by the control unit 10 or another control device (not shown). In this case, the control unit 10 or other control device calculates the recovery rate from the temperature information of each pipe acquired by the thermography 8, and controls the flow rate adjustment valves V21, V22, and the like so that the calculated recovery rate becomes the set value. Adjust the opening of V31 and V32.

In the present embodiment, the thermography 8 is used to detect changes over time in the surface temperature of each piping that constitutes the permeated water branch lines L21, L22 and the concentrated water branch lines L31, L32. A thermocouple may be installed on the surface of each pipe. In addition, in order to generate hot water to be supplied to the membrane module unit 3, instead of heating the raw water flowing through the bypass line L4 with the heat exchanger 7, the raw water in the raw water tank 2 is directly heated. The raw water in 2 may be replaced with warm water.

In this embodiment, the performance diagnosis process of the present invention is applied to two membrane modules (separation membranes), but it can be applied not only to three or more membrane modules but also to a single membrane module. It goes without saying that there is. Furthermore, the performance diagnosis process of the present invention can also be applied to a membrane module unit 3 in which a plurality of membrane modules connected in parallel are installed in multiple stages. FIG. 2 is a schematic diagram showing an example of the configuration of such a membrane module unit. In the membrane module unit 3 shown in FIG. 2, the membrane modules 31 and 32 at each stage have the same configuration, and the concentrated water from the first stage membrane modules 31 and 32 is transferred to the second stage membrane modules 31 and 32. The concentrated water from the membrane modules 31 and 32 of the second-stage membrane modules 31 and 32 is discharged to the outside through the concentrated water line L3. Further, both the permeated water from the first-stage and second-stage membrane modules 31 and 32 are supplied to the treated water tank or use point through the permeated water line L2. In such a membrane module unit 3, the temperature information of the piping in the first-stage and second-stage membrane modules 31 and 32 may be acquired together or separately. Although not shown, even in such a membrane module unit 3, the permeated water branch lines L21, L22 and concentrated water branch lines L31, L32 at each stage may be provided with the above-mentioned flow rate regulating valves. good. Further, there is no particular restriction on the number of membrane module stages or the number of membrane modules in each stage. For example, the number of membrane module stages may be three or more, and the number of membrane modules in each stage may be one or three or more. It may be.

(Second embodiment)
FIG. 3(a) is a schematic diagram showing the configuration of a membrane separation device according to a second embodiment of the present invention, and FIG. 3(b) is a membrane module constituting the membrane separation device of FIG. 3(a). FIG. 2 is a schematic diagram showing the configuration of a unit. Hereinafter, configurations similar to those in the first embodiment will be denoted by the same reference numerals in the drawings, explanations thereof will be omitted, and only configurations different from the first embodiment will be described.

This embodiment is a modification of the first embodiment, and the temperature information of each pipe constituting the overwater branch lines L21 and L22 is not based on the time change when the surface temperature of the pipe increases, but when the surface temperature of the pipe decreases. This embodiment differs from the first embodiment in that information regarding temporal changes in is acquired. To this end, in this embodiment, instead of the heat exchanger 7 (and bypass line L4) of the first embodiment, a pipe heating device 9a, which externally heats each pipe constituting the permeated water branch lines L21 and L22, 9b is provided. Examples of the pipe heating devices 9a and 9b include infrared heaters and band heaters.

The performance diagnosis process of this embodiment is started when the normal operation (water sampling operation) of the membrane separator 1 is stopped. That is, when the pressurizing pump 4 is stopped and the valve V1 of the raw water line L1 and the valve (not shown) of the permeated water line L2 are closed, the performance diagnosis process is started. When the performance diagnosis process is started, the pipe heating devices 9a and 9b are activated to heat each pipe constituting the permeated water branch lines L21 and L22. When the surface temperature of each pipe reaches a predetermined temperature (for example, 50°C), the pipe heating devices 9a and 9b are stopped, and the valve V1 of the raw water line L1 and the valve (not shown) of the permeated water line L2 are closed. When the pressure pump 4 is opened and the pressure pump 4 is activated, the water sampling operation is restarted. At this time, as the raw water at room temperature flows through the permeated water branch lines L21 and L22, the pipes forming each line L21 and L22 are cooled, and their surface temperature gradually decreases. The image is taken as a thermal image. After that, the method of acquiring temperature information of each piping from the photographed thermal image and determining whether or not the membrane modules 31 and 32 (separation membranes 31a and 32a) are clogged based on the acquired temperature information of the piping is as follows. This is similar to the first embodiment. Although not shown, in this embodiment as well, the permeated water branch lines L21 and L22 and the concentrated water branch lines L31 and L32 may be provided with the above-mentioned flow rate control valves.

1 Membrane separation device 2 Raw water tank 3 Membrane module unit 31, 32 Membrane module 31a, 32a Separation membrane 4 Pressure pump 7 Heat exchanger 8 Thermography 9a, 9b Piping heating device 10 Control section L1 Raw water line L11, L12 Raw water branch line L2 Permeated water line L21, L22 Permeated water branch line L3 Concentrated water line L31, L32 Concentrated water branch line L4 Bypass flow line V1 to V3 Valve

Claims (6)

A method for diagnosing the performance of a membrane separation device for identifying which separation membrane is blocked among a plurality of separation membranes each of which separates raw water into permeated water and concentrated water, the method comprising:
A step of supplying warm water to the predetermined separation membrane through a raw water line that supplies raw water to a predetermined separation membrane among the plurality of separation membranes , and causing the permeated water from the predetermined separation membrane to flow through a permeated water line. and,
While the hot water is flowing through the permeated water line, acquiring a temporal change in the surface temperature of piping constituting the permeated water line;
a step of determining whether or not the predetermined separation membrane is clogged based on the acquired time change ;
In the step of determining the presence or absence of occlusion, the obtained time change is the time change obtained when the predetermined separation membrane is not occluded, or the time change obtained when the predetermined separation membrane is not occluded. A method for diagnosing the performance of a membrane separation apparatus , the method comprising determining whether or not the predetermined separation membrane is clogged based on whether or not the change is slower than the time change. A method for diagnosing the performance of a membrane separation device for identifying which separation membrane is blocked among a plurality of separation membranes each of which separates raw water into permeated water and concentrated water, the method comprising:
a step of externally heating piping constituting a permeated water line through which permeated water from a predetermined separation membrane among the plurality of separation membranes flows ;
After heating the piping, supplying raw water to the predetermined separation membrane through a raw water line that supplies raw water to the predetermined separation membrane, and causing it to flow through the permeated water line;
While the raw water is flowing through the permeated water line, acquiring a temporal change in the surface temperature of the piping;
a step of determining whether or not the predetermined separation membrane is clogged based on the acquired time change ;
In the step of determining the presence or absence of occlusion, the obtained time change is the time change obtained when the predetermined separation membrane is not occluded, or the time change obtained when the predetermined separation membrane is not occluded. A method for diagnosing the performance of a membrane separation apparatus , the method comprising determining whether or not the predetermined separation membrane is clogged based on whether or not the change is slower than the time change. 2. The method according to claim 1, wherein the step of acquiring the temporal change in the surface temperature includes photographing the radiant heat from the piping as a thermal image using thermography, and acquiring the temporal change in the surface temperature from the photographed thermal image. 2. The method for diagnosing the performance of a membrane separation device according to 2. The method for diagnosing the performance of a membrane separation device according to claim 1 or 2, wherein the step of acquiring the temporal change in the surface temperature includes acquiring the temporal change in the surface temperature from a thermocouple installed on the surface of the piping. . multiple separation membranes, each of which separates raw water into permeate water and concentrated water;
a plurality of raw water lines that supply raw water to the plurality of separation membranes;
a plurality of permeate lines through which permeate water from the plurality of separation membranes flows;
heating means for heating raw water supplied to the plurality of separation membranes through the plurality of raw water lines to generate hot water;
Acquisition means for acquiring temperature information of a plurality of pipes forming the plurality of permeated water lines ;
determination means for identifying which separation membrane among the plurality of separation membranes is blocked based on the temperature information acquired by the acquisition means ;
The acquisition means is configured to operate the permeate line while the hot water supplied to a predetermined separation membrane among the plurality of separation membranes is flowing through the permeate line through which the permeate water from the predetermined separation membrane flows. Obtain the temporal change in surface temperature of the constituent piping,
The determination means determines whether the time change acquired by the acquisition means is the time change acquired when the predetermined separation membrane is not clogged, or the time change acquired with respect to another separation membrane that is not clogged. A membrane separation device that determines whether or not the predetermined separation membrane is clogged based on whether or not the change over time is slower than the change over time. multiple separation membranes, each of which separates raw water into permeate water and concentrated water;
a plurality of raw water lines that supply raw water to the plurality of separation membranes;
a plurality of permeate lines through which permeate water from the plurality of separation membranes flows;
heating means for externally heating a plurality of piping constituting the plurality of permeated water lines;
Acquisition means for acquiring temperature information of the plurality of pipes ;
determination means for identifying which separation membrane among the plurality of separation membranes is blocked based on the temperature information acquired by the acquisition means ;
The acquisition means allows raw water supplied to a predetermined separation membrane among the plurality of separation membranes to flow through the permeation water from the predetermined separation membrane after the plurality of permeate lines are heated by the heating means. While flowing through the permeated water line, obtain temporal changes in the surface temperature of the piping that constitutes the permeated water line,
The determination means determines whether the time change acquired by the acquisition means is the time change acquired when the predetermined separation membrane is not clogged, or the time change acquired with respect to another separation membrane that is not clogged. A membrane separation device that determines whether or not the predetermined separation membrane is clogged based on whether or not the change over time is slower than the change over time.

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