JPH08126882A - Device for controlling operation of water generating plant - Google Patents

Abstract

PURPOSE: To clean a membrane at an opportune time and to conduct automatic operation with the appropriate number of modules by diagnosing the contamination of the membrane based on the feed water pressure, osmotic pressure on the feed water side of a reverse-osmosis membrane module and flow rate of the permeated water. CONSTITUTION: The water permeability coefficient of the reverseosmosis process is obtained based on a means 27 for informing plant abnormality, the feed water pressure measured by the means 7 to 9 for measuring the state value of the plant, the osmotic pressure on the feed water side of a reverse-osmosis membrane module 2 and the flow rate of permeated water. When the membrane state value, i.e., the coefficient minus the initial value, is below a first reference value, the membrane is diagnosed as contaminated, and a cleaner 3 is operated. When the state value is above a second reference value, the membrane is diagnosed as deteriorated by a membrane state diagnosing means 23, and the abnormality informing means 27 is actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a desalination plant using a reverse osmosis membrane module.

[0002]

2. Description of the Related Art Conventionally, a desalination plant using a reverse osmosis membrane module is known. In controlling the operation of this desalination plant, it is desired to perform an appropriate operation according to the conditions of the raw water and the state of the membrane, and to perform an efficient operation such as extending the life of the membrane.

However, conventionally, since the membrane is regularly cleaned without monitoring the contamination of the membrane, it cannot be cleaned more than necessary to prevent the membrane from being soiled, or when the cleaning is required, the cleaning cannot be performed. There was an occasion.

For example, if the cleaning cycle comes before the membrane is not contaminated, chemicals are unnecessarily used, an operator is required to perform unnecessary work, and sudden pressure changes during cleaning adversely affect the membrane. give.

On the other hand, when the membrane is soiled before the cleaning cycle, it becomes clogged due to the soiling, which requires more pressure than necessary, or even when the soiling progresses and the cleaning cycle comes, the soiling becomes dirty. The membrane cannot be dropped and cannot be used, or pressure is applied to another membrane module, which causes deterioration of the membrane.

Further, since the fouling of the membrane is not uniform throughout the plant and differs depending on each series or membrane module, the proper cleaning time is different, and if the cleaning is carried out in the same cleaning cycle, the above problems occur. . Furthermore, since the conditions of raw water differ depending on the season and the conditions of the surrounding sea area, the time when the membrane is likely to be fouled and the time when fouling is likely to progress are different, so even in the same membrane module, the appropriate cleaning cycle is different each time, and the same as above. Problem occurs.

In the conventional constant cycle cleaning, these problems occur, so that it is not possible to prolong the life of an expensive membrane and perform efficient operation.

[0008]

By the way, in a desalination apparatus having a reverse osmosis membrane module, the amount of permeated salt increases as the water temperature rises, and the amount of permeated salt increases even if the membrane deteriorates. Conventionally, it has been attempted to monitor the amount of permeated salt to diagnose membrane fouling, but it is not possible to detect early whether the increase in the amount of permeated salt is due to an increase in water temperature or deterioration of the membrane. , The exchange of the membrane may be delayed, or conversely, the usable membrane may be exchanged. Further, it is considered that the membrane should be replaced regularly because of fear of an accident due to deterioration of the membrane, but a usable membrane may be replaced.
As described above, it is not possible to make the most effective use of an expensive membrane by monitoring the amount of permeated salt and regularly changing the membrane.

Further, in a fresh water generator having a reverse permeable membrane module, the amount of permeated water has a property of increasing as the water temperature rises, and is also proportional to the supply water pressure. Conventionally, in order to obtain a certain amount of water from a fresh water generator, the supply water pressure is reduced when the water temperature rises, or the number of operating membrane modules is changed about once a year. Since the capacity of the fresh water generator increases remarkably as the water temperature rises, if this is used to change the number of membrane modules to be operated, the operating cost can be reduced. Further, when changing the number of membrane modules to be operated, it is more efficient to selectively suspend the membranes that are contaminated or deteriorated for cleaning. However, in the conventional operation, the number of membrane modules was not changed significantly, so that efficient operation could not be performed.

The present invention has been made in consideration of the above points, and it is possible to reduce the contamination of the membrane, deterioration of the membrane, and conditions of raw water.
It is an object of the present invention to provide an operation control device for a desalination plant using a reverse osmosis membrane module, which is capable of cleaning the membrane at an appropriate time and enabling automatic operation with an appropriate number of membrane modules.

[0011]

According to the first aspect of the present invention,
A reverse osmosis membrane module for desalting through supply water to make permeate and at the same time impervious water as concentrated water, a cleaning device for regularly cleaning the reverse osmosis membrane module, and a measuring means for measuring the state value of the plant In an operation control device of a fresh water plant having, an abnormality notifying means for notifying a plant abnormality, a supply water pressure measured by the measuring means, a supply water side membrane surface osmotic pressure of a reverse osmosis membrane module, and a permeated water flow rate. Based on, the water permeability coefficient of the reverse osmosis process is calculated from the following formula,

[0012]

[Equation 4] The membrane state value obtained by subtracting the initial value from this water permeability coefficient is
When the film thickness is below the first reference value, it is diagnosed that the film is dirty and the cleaning device is operated, and when it is above the second reference value, the film deterioration is diagnosed and the abnormality notifying unit is operated. And a means for controlling the operation of the desalination plant.

According to a second aspect of the present invention, the membrane condition diagnosing means diagnoses the membrane fouling if the value obtained by subtracting the initial value from the water permeation coefficient is less than or equal to the first reference value and if it is restored within a predetermined time. The operation control device of the desalination plant according to claim 1, further comprising fuzzy inference means that does not diagnose the deterioration of the membrane if the film is recovered within a predetermined time even if it is not less than the second reference value.

According to a third aspect of the invention, the fuzzy inference means further diagnoses the membrane flow based on the feed water pressure and the permeate concentration, and when the number of modules of the reverse osmosis membrane module input changes. The operation control device for a desalination plant according to claim 2, wherein the diagnosis of the membrane is not performed. In the invention according to claim 4, the permeated water concentration, the supplied water concentration and the supplied water flow rate measured by the measurement means are further input to the membrane state diagnosis means, and the permeated water concentration, the supplied water concentration, the permeated water flow rate and the supply water are supplied. It is possible to determine the intermembrane concentration based on the water flow rate, determine the permeated salt content from the permeated water concentration and the feed water concentration, and correct the membrane state value by the salt permeation coefficient obtained from the intermembrane concentration and permeated salt content. It is an operation control device of a desalination plant according to claim 1.

According to a fifth aspect of the present invention, the membrane condition diagnosing means corrects the water permeation coefficient and the salt permeation coefficient on the basis of the number of operating modules of the reverse osmosis membrane module input. It is an operation control device of a desalination plant.

According to the sixth aspect of the present invention, the membrane state diagnosis means can learn the causal relationship for obtaining the membrane state value from the plant state value by using the plant state value as an input signal and the membrane state value as a teacher signal. The operation control device for a fresh water plant according to any one of claims 1 to 5, further comprising a membrane state learning unit having a built-in neural network.

According to a seventh aspect of the present invention, a plurality of reverse osmosis membrane module devices are provided, and the reverse osmosis membrane modules that have been diagnosed by the membrane state diagnosing means as having dirt on the membrane are to be cleaned in order. When a plurality of membrane modules are concentrated at the same time, a membrane cleaning planning means is further provided to disperse the cleaning time so that other membrane modules are cleaned earlier by a predetermined time based on the membrane module having the latest cleaning sequence among them. The operation control device of the desalination plant according to claim 1.

According to an eighth aspect of the present invention, a plurality of reverse osmosis membrane module devices are provided, the module number determining means for determining an appropriate number of operating modules from the supply water pressure and the supply water temperature, and the module number determining means. The operation of the desalination plant according to claim 1, further comprising module operation planning means for determining which membrane module is to be operated based on a signal from the module and a past operation history of each module. It is a control device.

According to a ninth aspect of the present invention, there is provided a reverse osmosis membrane module for desalting and supplying permeated water through feed water, and a non-permeated water as concentrated water, and a cleaning device for periodically cleaning the reverse osmosis membrane module. In the operation control device of the fresh water plant having a measuring unit for measuring the state value of the plant, an abnormality notifying unit for notifying an abnormality of the plant, the supply water pressure measured by the measuring unit, the supply water temperature, the supply Based on the water concentration, permeate flow rate, concentrated water pressure, and the membrane area input from the outside, the water permeation coefficient of the reverse osmosis process is calculated from the following formula,

[0020]

(Equation 5) A value obtained by dividing the water permeation coefficient by the initial value is taken as a membrane state value, and when the membrane state value is equal to or less than the first reference value, it is determined that the membrane is dirty and the cleaning device is operated to Membrane condition diagnosing means for deciding that the membrane is deteriorated when it is equal to or more than 2 reference values and activating the abnormality notifying means, and stopping operation of the plant when it is equal to or more than the third reference value. It is an operation control device for a fresh water plant.

According to a tenth aspect of the present invention, a plurality of reverse osmosis membrane modules are provided, and the number of modules in a short-term storage state and the long-term state are determined based on the water temperature measured by the measuring means, the target treatment flow rate and the operation policy input from the outside. The number of modules in a long-term storage state that can be stored physically, the number of operating modules, and the operating module number determining means, the operating module number from the operating module number determining means, the short-term storage module number and the long-term storage module number, A cleaning order determination unit that determines the order of low-pressure cleaning and chemical cleaning based on the film condition value output from the film condition diagnosis unit, and a history of past film cleaning when a plurality of film modules to be cleaned are concentrated at the same time. Therefore, the cleaning time is dispersed so that other membrane modules are cleaned earlier by a predetermined time, based on the membrane module with the slowest cleaning sequence among them. And Kiyoshi planning means an operation control device for a desalination plant according to claim 9, characterized in that it further comprises a.

According to the eleventh aspect of the present invention, the membrane condition diagnosing means is such that when the permeated water conductivity measured by the measuring means and its rate of change are below the respective lower limit reference values determined by the function of the water temperature, the membrane is fouled. If the permeate conductivity and its change rate are above the respective upper limit reference values determined by the function of the water temperature, it is judged that the membrane is deteriorated. The operation control device for a desalination plant according to claim 9, further comprising a conductivity diagnostic means for prompting stop and replacement of the membrane.

According to a twelfth aspect of the present invention, the membrane state diagnosing means is configured such that the supply water pressure measured by the measuring means and its rate of change,
When the concentrated water pressure and the rate of change thereof are equal to or higher than the respective reference values determined by the function of the water temperature, it is judged that the membrane is dirty, and the pressure diagnosing means prompting the membrane to be washed, the supply water pressure and the concentration. When the differential pressure of the water pressure is equal to or higher than a reference value determined by a function of the permeated water flow rate, it is determined that the membrane is dirty, and a differential pressure diagnosing means for prompting cleaning of the membrane is provided. It is an operation control device of the desalination plant according to claim 9.

According to the thirteenth aspect of the present invention, the membrane condition diagnosing means is abnormal because the membrane deterioration may occur when the ORP and ORP integrated values of the feed water measured by the measuring means are equal to or greater than the respective reference values. The operation control device for a desalination plant according to claim 9, further comprising an ORP diagnosis means for activating the notification means.

According to a fourteenth aspect of the present invention, in the membrane state diagnosing means, when the feed water pH and the pH integrated value measured by the measuring means are equal to or more than the respective reference values, hydroxide is deposited and the membrane is clogged. PH that activates the abnormality notification means
The operation control device of a desalination plant according to claim 9, further comprising a diagnostic means.

According to a fifteenth aspect of the present invention, the membrane state diagnosing means is configured so that the feed water concentration, the feed water flow rate, the feed water temperature, the permeate flow rate, the permeate concentration measured by the measuring means, and the membrane area input from the outside. Based on, the salt permeation coefficient of the reverse osmosis process is calculated from the following equation,

[0027]

(Equation 6) If the salt permeation coefficient is less than or equal to the first reference value, it is determined that the membrane is dirty and the cleaning device is activated. If it is greater than or equal to the second reference value, it is determined that the membrane is deteriorated. 10. The operation control device for a desalination plant according to claim 9, further comprising a salt permeation coefficient diagnosing means for activating the abnormality notifying means and stopping the operation when the value is not less than the third reference value.

According to a sixteenth aspect of the present invention, the membrane state diagnosing means is based on the feed water pH, the feed water SDI, the feed water ORP, the water permeation coefficient, the salt permeation coefficient, the permeate concentration and the feed water concentration measured by the measuring means. Each item indicating the state of the membrane consisting of the calculated desalination rate, the differential pressure between the supply water pressure and the concentrated water pressure, and the difference between the target value of the supply water pressure and the process value is displayed with the vertex of the polygon as the axis. The operation control device for a desalination plant according to claim 9, further comprising polygonal diagnosis means for observing a state of the membrane by observing a polygonal shape that changes due to contamination or deterioration of the membrane. .

[0029]

According to the first aspect of the present invention, in the membrane condition diagnosing means, the water permeation coefficient of the reverse osmosis process is determined based on the feed water pressure, the feed water side osmotic pressure of the reverse osmosis membrane module, and the permeate flow rate. When the value obtained by subtracting the initial value from the water permeation coefficient is less than or equal to the first reference value, the membrane is diagnosed as contaminated, and when the value is greater than or equal to the second reference value, membrane deterioration is diagnosed. When the membrane condition diagnostic means diagnoses the membrane fouling, when the reverse osmosis membrane module is washed by the washing device and the membrane deterioration is diagnosed,
The abnormality notification means notifies the plant abnormality.

According to the second aspect of the present invention, by providing the fuzzy inference means, even if the water permeability coefficient fluctuates depending on the condition of the plant, if it returns within a predetermined short time, the cleaning device or the abnormality notifying means. Does not operate unnecessarily.

According to the third aspect of the present invention, the fuzzy inference means further diagnoses the membrane fouling based on the feed water pressure and the permeated water concentration, and when the number of modules fluctuates which disturbs the membrane fouling diagnosis, the membrane fluctuates. Do not diagnose dirt on the.

According to the fourth aspect of the invention, the intermembrane concentration and the permeated salt content are obtained by the membrane state diagnostic means, and the membrane state value is corrected according to the actual conditions of the plant by the intermembrane concentration and permeated salt content. can do.

According to the invention of claim 5, the water permeation coefficient is further corrected in accordance with the actual situation by correcting the water permeation coefficient and the salt permeation coefficient based on the number of operating modules in the membrane state diagnosis means. be able to.

According to the sixth aspect of the invention, the membrane state learning means of the membrane state diagnosing means uses the plant state value as an input signal and the membrane state value as a teacher signal by a neural network to use the plant state value and the membrane state. By learning the causal relationship with the value, the film state value can be accurately obtained.

According to the seventh aspect of the present invention, when the reverse osmosis membrane modules, which are diagnosed by the membrane state diagnosing means as being contaminated with the membrane, are concentrated at the same time, the membrane cleaning planning means
It is possible to disperse the concentration of the cleaning time by advancing the cleaning time of other membrane modules based on the membrane module having the latest cleaning order.

According to the invention described in claim 8, the number of operating modules is determined from the supply water pressure and the water temperature of the supply water by the module number determining means, and the module operation planning means is determined by the operation module number thus determined. Determines which membrane module to operate.

According to the ninth aspect of the invention, in the membrane state diagnosing means, the supply water pressure, the supply water temperature, the supply water concentration,
Based on the permeate flow rate, the concentrated water pressure, and the membrane area entered by the operator, the water permeation coefficient of the reverse osmosis process is obtained, and the value obtained by dividing this water permeation coefficient by its initial value is taken as the membrane state value. If the state value is less than or equal to the first reference value,
It is judged that the membrane is dirty, the membrane cleaning device is activated, and the second
When it is above the reference value, it is judged that the film is deteriorated and the abnormality notifying means is activated, and when it is above the third reference value, the operation is stopped.

According to the tenth aspect of the present invention, the operating module number determining means determines the number of modules in the short-term storage state, the number of modules in the long-term storage state, and the number of operating modules. Further, the cleaning order determining means determines the order of low-pressure cleaning and chemical cleaning from the number of operating modules, the number of short-term storage modules, the number of long-term storage modules, and the membrane state value. Further, in the cleaning planning means, when a plurality of membrane modules to be cleaned are concentrated at the same time, other membrane modules are specified from the past membrane cleaning history based on the membrane module having the slowest cleaning sequence among them. Disperse the cleaning time, such as cleaning earlier in time.

According to the eleventh aspect of the invention, in the conductivity diagnosing means, when the permeated water conductivity and the rate of change thereof are below the respective lower limit reference values determined by the function of the water temperature,
It is judged that the membrane is dirty, and the membrane is urged to be cleaned. Furthermore, when the permeated water conductivity and its change rate are higher than the respective upper limit reference values determined by the function of the water temperature, the membrane is deteriorated. Judge that the membrane should be stopped and exchanged.

According to the twelfth aspect of the present invention, in the pressure diagnosing means, when the supply water pressure and its rate of change, and the concentrated water pressure and its rate of change are each reference values determined by a function of the water temperature or more. Judges that the membrane is dirty, and prompts the membrane to be washed.

Further, in the differential pressure diagnosis means, when the differential pressure between the supply water pressure and the concentrated water pressure is equal to or higher than the reference value determined by the function of the permeated water flow rate, it is judged that the membrane is dirty, and the membrane Prompt for cleaning.

According to the thirteenth aspect of the invention, in the ORP diagnosing means, when the supply water ORP and the integrated ORP value are equal to or more than the respective reference values, there is a risk of deterioration of the membrane.
The abnormality notification means is activated.

According to the fourteenth aspect of the present invention, in the pH diagnosis means, when the pH of the supplied water and the pH integrated value thereof are equal to or more than the respective reference values, there is a risk that hydroxide will precipitate and the film will be clogged. Therefore, the abnormality notifying means is activated.

According to the fifteenth aspect of the invention, in the salt permeation coefficient diagnosing means, based on the feed water concentration, the feed water flow rate, the feed water temperature, the permeate flow rate, the permeate concentration, and the membrane area,
The salt permeation coefficient of the reverse osmosis process is determined, and if the salt permeation coefficient is less than or equal to the first reference value, it is determined that the membrane is dirty and the cleaning device is operated. Further, when it is equal to or more than the second reference value, it is determined that the film is deteriorated and the abnormality notifying means is activated, and when it is equal to or more than the third reference value, the operation is stopped.

According to the sixteenth aspect of the present invention, in the polygon diagnosis means, the feed water pH, the feed water SDI, and the feed water O.
RP, water permeation coefficient, salt permeation coefficient, desalination rate, differential pressure between feed water pressure and concentrated water pressure, and each item indicating the state of the membrane consisting of feed water pressure are displayed with the vertex of the polygon as the axis. Then, the state of the film is grasped by observing the polygonal shape that changes due to the dirt and deterioration of the film.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are diagrams showing a first embodiment of an operation control device for a water desalination plant using a reverse osmosis membrane module according to the present invention.

In FIG. 1, the desalination process is constructed by connecting a high-pressure pump 1 and a plurality of reverse osmosis membrane modules 2 having a membrane 2a, and a cleaning device 3 is connected to the reverse osmosis membrane module 2. There is. Further, among these, a plurality of reverse osmosis membrane modules 2 are connected in parallel.

A sampling pump 5 is installed in the feed water inflow path 4 from the high-pressure pump 1 to the reverse osmosis membrane module 2, and the raw water passes through the sampling pipe 6 to measure the state value of the plant, for example, SDI total 7, OR
It is sent to a P meter (oxidation / reduction potentiometer) 8 and a pH meter 9. Further, in the supply water inflow path 4, a water temperature gauge 10 and a supply water pressure gauge 1
1, a supply water concentration meter 12, and a supply water flow meter 13 are installed.

The reverse osmosis membrane module 2 is connected to a permeated water outflow passage 14 for permeated water that permeates the membrane 2a and a concentrated water outflow passage 15 for concentrated water that does not permeate the membrane 2a and is concentrated in salt. .

A sampling pump 16 is installed in the permeated water outflow passage 14, and the permeated water is collected in the sampling pipe 1.
It is sent to the permeated water concentration meter 18 through 7. Further, a permeate flow meter 19 is installed in the permeate outflow passage 14,
On the other hand, a concentrated water pressure gauge 20 is installed in the concentrated water outlet 15.

The operation control device 21 of the reverse osmosis membrane desalination plant according to the present invention comprises a high pressure pump 1 and a reverse osmosis membrane module 2.
To send the instructions to achieve the desired operation,
As shown in FIG. 1 described in detail below, the operation control device 21 of the reverse osmosis membrane desalination plant uses the fuzzy inference means 22 to diagnose the dirt and deterioration of the reverse osmosis membrane 2
3 and the film state display means 24 for displaying the dirt and deterioration of the film.
And the cleaning confirmation means 25 for confirming to the operator that the automatic cleaning of the film is started based on the diagnosis result, and the cleaning device 3 for automatically cleaning the film.
And a membrane cleaning means 26 for operating the.

The diagnosis result from the film state diagnosis means 23 is notified to the operator by the abnormality notification means 27. Further, the relationship between the input process value and the result of diagnosis of the dirt or deterioration of the film is learned by the film state learning means 28 using the neural network, and the accuracy of the film state diagnosis is improved.

Further, the order of cleaning each membrane module by the membrane cleaning planning means 29 is based on the dirt and deterioration of the diagnosed membrane output from the membrane state diagnosing means 23, the past history of membrane cleaning, and the cleaning capacity of the cleaning apparatus. An appropriate number of operating membrane modules is determined by the module number determination means 30 from the water temperature of the supplied water and the target permeated water amount input by the operator.

The determined module number is displayed by the appropriate module number display means 31, and the module number change confirmation means 32 confirms to the operator whether the module number is automatically changed. After confirming the number of modules, the number of modules is automatically changed by the number-of-modules changing unit 33, and the number of modules output from the number-of-modules determining unit 30, the past operation history of each module, and the operation policy input by the operator An appropriate operation module is selected in the operation planning means 34.

Further, based on the results output from the membrane cleaning planning means 29 and the module operation planning means 34, and the operation policy input by the operator, the comprehensive planning means 35 makes a comprehensive judgment to clean / operate the membrane. Take a break. Signals are exchanged with the operator via the man-machine interface means 36.

On the other hand, SDI meter 7, ORP meter 8, pH meter 9, water temperature meter 10, feed water pressure gauge 11, feed water concentration meter 12,
Supply water flow rate 13, permeate concentration meter 18, permeate flow meter 1
9 and signals from the concentrated water pressure gauge 20 are input to the operation control device 21, and at the same time, weather information is input to the operation control device 21 through the man-machine interface means 36.

Further, from the operation control device 21 of the reverse osmosis membrane desalination plant, the state information of the dirt and deterioration of the membrane, the abnormality information of the device, the appropriate number of modules are output through the man-machine interface means 36, and the cleaning device 3 Also, a cleaning start command and an operation start / stop command are output to the reverse osmosis membrane module 2, respectively.

Next, the operation of this embodiment having such a configuration will be described.

First, the feed water pressure gauge 1 installed in the plant
1, the feed water pressure Pf, the feed water temperature Temp, and the permeate flow rate Qp, which are respectively measured by the permeated water flow meter 19 and the water temperature meter 10, are input to the membrane state diagnostic means 23, and the membrane state diagnostic means 23 produces them. The water permeation coefficient A under the use condition indicating the water capacity is obtained by using the equation (1) which is a transport equation of the reverse osmosis process.

The reverse osmotic pressure difference ΔP between the membranes and the osmotic pressure difference Δπ between the membranes of the equation (1) are expressed by the following equations (2) and (3), respectively.
And it is calculated using the equation (4). In the formula (4), the supply water side film surface concentration Cm is the supply water concentration Cf and the recovery rate RR.
Although it is a value that changes due to the change of, the permeated water amount is constant when the operation is performed, and therefore is assumed to be constant here in the calculation. The recovery rate means the ratio of the amount of permeated water to the amount of supplied water.

[0061]

(Equation 7) A: Water permeation coefficient under use conditions Qp: Permeate flow rate ΔP: Reverse osmotic pressure difference between membranes Δπ: Osmotic pressure difference between membranes F: Unit membrane area ΔP = Pf-Pp (2) Pf: Supply water pressure Pp : Permeate pressure (approximately 0) Δπ = πm−πp (3) πm: Supply water side membrane surface osmotic pressure πp: Permeate osmotic pressure (approximately 0) πm = Kπ × Temp × Cm (4) Kπ : Parameter Temp: Water temperature Cm: Membrane surface concentration on the feed water side The water permeability coefficient A under the operating conditions is the feed water pressure Pf and the water temperature Te.
Since it changes with mp, the water permeability coefficient Astd under standard conditions
(5) is converted to. The number of temperature correction functions (6) and the pressure correction function (7) are obtained by conducting an experiment for each installation location of the reverse osmosis membrane module.

[0062]

(Equation 8) Astd: Water permeation coefficient under standard conditions Kat: A value temperature correction coefficient Kap: A value pressure correction coefficient Kat = f (Temp) ...... (6) Kap = f (Temp) ...... (7) Present under standard conditions The water permeability coefficient Astd of No. 2 and the initial water permeability coefficient A0 before the membrane operation are compared based on the formula (8),
From the formula (8), the film state value S is the film fouling reference value (first reference value)
If it is lower than α, it can be judged that the film is dirty. Further, the value from the formula (8) is the film deterioration reference value (second reference value).
If it increases above β, it is diagnosed that there is a risk of deterioration (that is, damage).

S = Astd-A0 (t / t0) ^-m (8) S: Membrane state value A0: Initial water permeability coefficient (standard condition) m: Parameter t: Current time t0: Membrane use start time Next Then, the permeated concentrated pressure difference ΔPm, which is the difference between the permeated water pressure and the concentrated water pressure, is calculated using the equation (9). The permeation concentration pressure difference ΔPm obtained by the equation (9) is compared with the reference value by the equation (10) which is a reference equation, and if it increases, it is determined that the membrane is dirty. The parameter of the reference equation (10) of the permeation concentration difference ΔPm is obtained by conducting an experiment for each installation location of the reverse osmosis membrane module.

[0064] ΔPm = Pf-Pb ...... (9 ) Pb: concentrated water pressure ΔPm = Kpm0 + Kpm1 Qf + Kpm2 Qf 2 ...... (10) where Kpm0: Parameters KPM1: Parameter Kpm2: a parameter.

Further, in the membrane state display means 24, the membrane state value S which is the result of the membrane state diagnosis means 23, the water permeation coefficient Astd in the standard state, the permeated water flow rate Qp, the feed water pressure f, the water temperature Temp and other process values. Is also displayed to notify the operator of the state of dirt and deterioration of the film and the progress thereof.

Further, the cleaning confirmation means 25 notifies the operator that it is judged that the film should be cleaned based on the diagnosis result of the film state diagnosis means 23. When the operator determines that it is appropriate to start the automatic cleaning of the membrane, he / she inputs the fact to the operation control device 21 through the man-machine interface means 36, and thus the operator confirms the start of cleaning.

Next, the membrane cleaning means 26 outputs a cleaning command to the cleaning device 3 for the membrane module 2 for which a cleaning request has been made, after confirmation by the operator via the cleaning planning means 29 and the comprehensive planning means 35 described later. At the same time, the abnormality notifying means 27
Then, based on the result of the film state diagnosis means 23, the operator is notified of the deterioration of the film and urged to check and replace it.

Next, the function of the film state diagnosis means 23 will be described in detail below.

The membrane state diagnosing means 23 does not obtain the membrane state value S merely by comparing the water permeation coefficient Astd converted to the standard condition with the initial value as described above, but uses the fuzzy inference means 22 to It is possible to diagnose the contamination and deterioration of the film in consideration of non-linear factors such as film properties, site properties and operator's intuition. In this case, the fuzzy inference means 22 makes a diagnosis according to the following rules, for example.
Rules can be added.

S ← fuzzy inference rule: 1) When the current water permeability coefficient Astd is smaller than the water permeability coefficient A0 in the initial state, the membrane is dirty.

2) The membrane is fouled when the supply water pressure Qf increases significantly in a short period of time during a constant permeate flow rate operation.

3) In a state where the permeate flow rate is constant and the membrane is not contaminated, if the water temperature Temp rises, the unit membrane area F and the permeate flow rate Qp per pressure increase, so that the supply water pressure Pf. Decreases.

Therefore, if the supply water pressure Qf increases when the water temperature Temp rises, the membrane is dirty.

4) Present water permeability coefficient Ast under standard conditions
d and the initial water permeation coefficient A0 before the membrane operation are compared based on the equation (8), and even if the value is reduced to the membrane fouling reference value α or less from the equation (8), if it is a short period, The membrane is not considered dirty. Further, according to the equation (8), even if the value increases to the film deterioration reference value β or more, there is no fear of deterioration for a short time.

5) When the permeated water flow rate Qp is greatly reduced in a short period of time during a constant operation of the permeated water flow rate, or the permeated water concentration Cp
If the value rises sharply, the membrane may be ruptured.

Further, in the membrane state diagnosing means 23, the membrane state value S is not obtained only by comparing the water permeation coefficient Astd converted into the standard condition with the initial value, but the permeate concentration Cp, the feed water concentration Cf, and the feed water concentration Cf are calculated. The membrane state value S may be corrected based on the water flow rate Qf so that the membrane state can be expressed more accurately. First, the salt permeation coefficient B is obtained by the equation (11) which is an equation of the reverse osmosis process.

Since the salt permeation coefficient B under the use condition changes depending on the supply water pressure Pf and the water temperature Temp, the salt permeation coefficient Bstd under the standard condition is converted by the equation (12). In this case, the temperature correction function (13) formula and the pressure correction function (14) formula are obtained by conducting an experiment for each installation location.

The concentration difference ΔC between the films in the equation (11) is
It is calculated using equations (15) and (16).

[0079]

[Equation 9] Cf: Supply water concentration RR: Recovery rate Sp: Salt permeability RR = Qp / Qf (16) Next, the initial salt permeability coefficient B0 before membrane operation is compared with the salt permeability coefficient Bstd converted to the standard state, The membrane state value S is corrected based on the degree of increase in salt permeability, and the diagnostic accuracy of membrane fouling and deterioration is improved. The comparative expression (17) is obtained by an experiment for each setting location.

S ′ = S × f (Bstd, B0) (17) B0: initial salt permeation coefficient before membrane operation Next, the corrected membrane state value S ′ obtained by the equation (17) is used. Based on this, membrane fouling and deterioration is diagnosed.

In a fresh water plant in which a plurality of reverse osmosis membrane modules 2 are arranged in parallel, the number of operating reverse osmosis membrane modules (the number of operating modules) is proportional to the fresh water producing capacity. Therefore, in the membrane state diagnosing means 23, the number of operating modules moj may be input and the membrane fouling or deterioration may be diagnosed in consideration of the change in the water production capacity. In this case, equation (1)
The expressions (1) 'and (11)' are used instead of the expression (11) to improve the accuracy of diagnosis of dirt and deterioration.

[0082]

[Equation 10] Furthermore, in the membrane state diagnosing means 23, feed water SDI showing the concentration of suspended matter in the feed water, feed water ORP showing the oxidizing ability to accelerate deterioration, and precipitation of suspended substances or dissolved salts in the feed water on the membrane. The pH of the membrane corrected by Eq. (17) is adjusted by further inputting the pH of the supply water that affects the water quality and the weather information that has a large effect on the water quality of the raw water, and taking into consideration the promotion of membrane fouling and deterioration due to the conditions of these raw water. The state value S'may be further corrected by the equation (18) to improve the accuracy of the film stain and deterioration diagnosis.

S ″ = S ′ × f (SDI, ORP, pH, weather information) (18) Further, in the membrane state diagnosis means 23, conditions of raw water (number of operating modules moj, supply water pressure Pf, water temperature Temp, Permeate flow rate Qp, permeate concentration Cp, feed water concentration Cf, feed water flow rate Qf, feed water SDI, feed water ORP, feed water p
Not only H, weather information), but fuzzy reasoning means 22 may be used to diagnose the film fouling or deterioration in consideration of non-linear factors such as film characteristics, site characteristics, and operator's intuition. The example of the rule in this case is shown below. The aforementioned rules 1) to 5) are also used here. Rules can be added.

S ← Fuzzy reasoning rule: 6) When the permeate flow rate is constant and the membrane is not contaminated, the feed water pressure Pf and the permeate concentration Cp are
It is in inverse proportion.

Therefore, when the permeated water concentration Cp also increases when the supply water pressure Pf increases, the membrane is dirty. On the contrary, if the permeated water concentration Cp also decreases when the supply water pressure Pf decreases, the membrane is dirty.

7) When the module number moj is changed,
Since the supply water pressure Pf and the permeated water concentration Cp change accordingly, the membrane fouling is not diagnosed.

Further, in the membrane condition diagnosing means 23, the causal relation between the condition of the raw water and the membrane condition value is determined by the membrane condition learning means 28.
You may learn by. In this case, the membrane state diagnosis means 2
Raw water condition (input module number mo
j, supply water pressure Pf, water temperature Temp, permeate flow rate Qp,
Permeate concentration Cp, feed water concentration Cf, feed water flow rate Qf, feed water SDI, feed water ORP, feed water pH, weather information) are input to the neural network of the membrane state learning means 28 for a certain period of time. Input is repeated at regular intervals. Membrane condition diagnostic means 23 when input is accumulated
Using the state value S of the membrane, which is the output of the above, as a teacher signal, the neural network of the membrane state learning means 28 learns the causal relationship between the condition of the raw water and the state of the membrane by the back propagation method. By repeating this learning, it becomes possible to grasp the contamination of the film and the deterioration factor item. The learning result in the film state learning means 28 is notified to the operator and also reflected in the film state diagnosis means 23 to improve the accuracy of the film state diagnosis.

As described above, after the membrane state diagnosing means 23 diagnoses the contamination and deterioration of the membrane state, the diagnosis result is input to the membrane cleaning planning means 29. Membrane cleaning planning means 29
Then, from the film state value S indicating the degree of fouling of each film input from the film state diagnosing means 23, the past cleaning history of the film, and the cleaning ability of the cleaning device 3, the range of the film contamination to be cleaned is determined. The reverse osmosis membrane modules should be cleaned in order from the earliest reverse osmosis membrane module, and if the degree of fouling is the same, the cleaning time for each reverse osmosis membrane module should be changed according to the capacity of the cleaning device and the progress of fouling of the membrane. To plan. Further, when the cleaning of each reverse osmosis membrane module is concentrated, the cleaning time is determined so that the preceding cleaning is performed with respect to the set value of the membrane state with reference to the permeated water concentration Cp and the membrane cleaning range.

In this case, from the permeated water concentration Cp, the number of operating membrane modules moj and the permeated water flow rate Qp, the following (19)
The membrane cleaning range ΔS is determined as shown in equation (20).

If C1 ≦ Cp → ΔS = Sh if C1> Cp → ΔS = Si (19) C1: Membrane cleaning range switching concentration set value Cp: Permeate concentration Sh: Membrane cleaning range S1: Membrane cleaning range d2 = Qp / moj if C2 ≦ d2 → ΔS = Sh if C2> d2 → ΔS = S1 (20) d2: Permeation flow rate per module C2: Membrane cleaning range switching concentration set value Next, the membrane thus determined Based on the cleaning range ΔS, the cleaning time of the membrane module is determined as follows.

As shown in FIG. 2, the membrane state value S is divided for each membrane cleaning range ΔS (ΔS> 0) from the reverse osmosis membrane module (i-1), which has the lowest actual membrane state value S, and the membrane state value S is divided. The cleaning order is k, (k-1), and (k-
2) No., 1st (k: number of operating membrane modules) and the cleaning order are determined.

At this time, as shown in FIG. 2, there may be a case where the m state of the film state is concentrated in a certain film cleaning range (No. 1 pond,
No. 2 pond, No. 3 pond: m = 3), but in this order, the cleaning order 1 of each osmosis membrane module is in the order of longest operation duration (in the case of FIG. 2, the operation duration is 2nd pond> (No. 1 pond> No. 3 pond) and the membrane module with the slowest cleaning sequence (3
As shown in FIG. 3, the membrane state value of each membrane module is corrected by the membrane cleaning range ΔS as shown in FIG.

Si ′ = Si + (m−1) · ΔS (21) Si ′: Corrected virtual membrane state value of pond i Si: Actual membrane state value of pond i i m: Number of concentrated membrane modules 1: Cleaning sequence within the membrane cleaning range If there is no membrane module whose actual membrane state value has reached the membrane state set value, if the calculated virtual membrane state has reached the membrane state set value, the membrane Outputs a cleaning request to the module. However, at this time, the lower limit value SL of the film state at the start of cleaning is set for the film state value at the start of cleaning, and if the actual film state value is equal to or higher than this SL, the cleaning request is output.

When there is a membrane module in which the actual membrane state or the actual operation duration has reached the membrane state setting value and the operation duration setting value, the cleaning request is output to the membrane module with the highest priority. However, when there are a plurality of arrived membrane modules, the cleaning request is output in order from the membrane module having the largest actual membrane state value.

As described above, according to the equations (1) and (6), it has been shown that the water production capacity changes with the changes in the supply water pressure Pf and the supply water temperature Temp. , An appropriate number of operating membrane modules is determined according to changes in the supply water pressure Pf and the water temperature Temp.

Next, in the appropriate module number display means 31,
The appropriate number of modules calculated by the module number determination means 30 is displayed on the man-machine interface means 36 to notify the operator. Next, module number change confirmation means 32
Then, the operator confirms the automatic change in the number of modules in the cleaning confirmation means 25 in the same manner. At the same time, the module number changing means 33 outputs an operation / stop command for the reverse osmosis membrane module 2 after the operator confirmation by the module number change checking means 32, and automatically changes the module number.

The signal from the module number determining means 30 is also input to the module operation planning means 34, and the module operation planning means 34 receives the number of modules input from the module number determining means 30 and the past operation history of each module. , Which reverse osmosis membrane module is to be operated or stopped according to the operation policy input by the operator. If the operation policy from the operator is "use intensively the same reverse osmosis membrane module and replace it from the one with deteriorated membrane", select the membrane module that is used frequently and operate it. The membrane module, which is not used frequently, is stopped. If the policy is to "use the membranes on average", the membrane module that has been inactive for the longest time in the past should be used first, and the membrane module that has been operating the longest should be stopped first. .

The principle of the operation sequence determination method is the same as that used in the membrane cleaning planning means 29.

Next, the comprehensive planning means 35 operates which reverse osmosis membrane module according to the operation policy from the results output from the membrane cleaning planning means 29 and the module operation planning means 34 and the operation policy input by the operator. , Plan to pause. If it is a higher priority operation policy to properly clean the reverse osmosis membrane module, the module operation plan should be adjusted according to the membrane cleaning. Conversely,
If it is a higher priority operation policy to make the number of operating modules appropriate, the reverse osmosis membrane module cleaning plan is re-established so that the reverse osmosis membrane module to be stopped is cleaned.
However, when there are more membrane modules to be cleaned than the number of membrane modules to be stopped, the timing of changing the number of membrane modules is postponed.

The principle of the cleaning and operation sequence determination method is the same as that of the film cleaning planning means 29.

Next, a signal from the comprehensive planning means 35 is input to the module number changing means 33 and the membrane cleaning means 26,
Reverse osmosis membrane module 2 by module number changing means 33
The number of operating modules is adjusted, and the signal from the membrane cleaning means 26 activates the cleaning device 3 to clean the reverse osmosis membrane module 2. Second Embodiment Next, a second embodiment of the operation control device for a fresh water plant according to the present invention will be described.

FIG. 4 to FIG. 11 are views showing a second embodiment of the operation control device for a fresh water plant using the reverse osmosis membrane module according to the present invention.

In FIG. 4, the desalination process is constituted by connecting a high-pressure pump and a plurality of reverse osmosis membrane modules having a reverse osmosis membrane 2a, and the reverse osmosis membrane module 2 is connected with a cleaning device 3. There is.

A sampling pump 5 is installed in the feed water inflow path 4 from the high pressure pump 1 to the reverse osmosis membrane module 2, and raw water is passed through the sampling pipe 6 to measure the state value of the plant, for example, SDI total 7, OR
It is sent to the P meter 8 and the pH meter 9. Further, in the supply water inflow path 4, a water temperature gauge 10, a supply water pressure gauge 11, a supply water conductivity meter 1
2. A supply water flow meter 13 is installed.

The reverse osmosis membrane module 2 includes a reverse osmosis membrane 2a.
A permeated water outflow passage 14 for permeated water and a concentrated water outflow passage 15 for concentrated water which does not permeate the membrane 2a and in which salt is concentrated are connected.

A sampling pump 16 is installed in the permeated water outflow passage 14, and the permeated water is collected from the sampling pipe 1.
It is sent to the permeated water conductivity meter 18 through 7. Further, a permeated water flow meter 19 is installed in the permeated water outflow passage 14, and a concentrated water pressure gauge 20 is installed in the concentrated water outflow passage 15.

The operation control device 121 of the reverse osmosis membrane desalination plant according to the present invention has the man-machine interface means 122 for exchanging signals with the operator and sends instructions to the high pressure pump 1 and the reverse osmosis membrane module 2. It realizes the operation as intended.

As shown in FIG. 1, the operation control device 121 of the reverse osmosis membrane desalination plant has the supply water pressure Pf measured by the supply water pressure gauge 11 and the supply water temperature Te measured by the water temperature gauge 10.
mp, feed water concentration Cf measured with a feed water conductivity meter 12,
Based on the permeated water flow rate Qp measured by the permeated water flow meter, the concentrated water pressure Pb measured by the concentrated water pressure gauge 20, and the membrane area F input by the operator through the man-machine interface means 122, the water in the standard state Transmission coefficient As
The reverse osmosis membrane cleaning is provided with a membrane state diagnosing means 124 for calculating td, dividing it by an initial value to obtain a membrane state value S, and judging based on the value, and an abnormality notifying means 123 for notifying an operator of abnormality. The device 3 is operated and the operation of the high-pressure pump 1 and the reverse osmosis membrane module 2 is stopped.

Further, the operation control device 121 determines the number of modules Ns in the short-term storage state from the supplied water temperature Temp measured by the water temperature gauge 10, the target processing flow rate Qsv input by the operator through the my machine interface means 122, and the operation policy. And a number Nl of modules in a long-term storage state and a number Nr of operating modules, an operating module number determination means 125, a determined number Nr of operating modules, a number Ns of short-term storage modules, and a number Nl of long-term storage modules. When the cleaning order determining means 126 for determining the order of low-pressure cleaning and chemical cleaning based on the film status value S output from the first membrane status diagnosing means and a plurality of membrane modules to be cleaned are concentrated at the same time, The cleaning plan means 127 is provided to disperse the cleaning time from the cleaning history of the film.

As shown in FIG. 2, the membrane condition diagnostic means 124.
Is determined by the permeated water concentration Cp measured by the permeated water conductivity meter 18 and the reference value whose change rate ΔCp is determined by the function of the water temperature in order to further improve the accuracy of the diagnosis, and the abnormality notification means 123 A conductivity diagnostic means 128 for notifying the operator, cleaning the membrane, stopping and replacing the membrane;
The supply water pressure Pf measured by the supply water pressure gauge 11 and its change rate ΔPf, and the concentrated water pressure Pb measured by the concentrated water pressure gauge 20 and its change rate ΔPb are determined by a reference value determined by a function of the water temperature. Then, the abnormality notifying means 123 notifies the operator, and the pressure diagnosing means 129 for cleaning the membrane is further provided. Further, the abnormality notifying means 123 notifies the operator of the difference by the differential pressure Pd between the supply water pressure and the concentrated water pressure. It has a differential pressure diagnostic means 30 for notifying and cleaning the membrane.

Further, the membrane state diagnosis means 124 is the ORP meter 8
The supply water ORP and the integrated value ORPinf measured in
ORP diagnosing means 3 which is judged by the reference value and notifies the operator by the abnormality notifying means 123 to stop the operation of the membrane.
1, the pH of the supply water measured by the pH meter 9 and its integrated value pH
inf is determined by the reference value and the abnormality notifying means 123
The operator is notified of the pH by diagnosing the pH to stop the operation of the membrane, and 32, and the feed water concentration Cf measured by the feed water conductivity meter 12 and the feed water flow rate measured by the feed water flow meter 13. Qf, permeate flow rate Qp measured by permeate flow meter 19, permeate concentration C measured by permeate conductivity meter 18
Based on p and the membrane area F input by the operator through the man-machine interface means 122, the salt permeation coefficient Bstd of the reverse osmosis process in the standard state is obtained, judged by the reference value, and the abnormality notification means 123 notifies the operator. Then
It has a salt permeation coefficient diagnosis 33 for activating or stopping the reverse osmosis membrane cleaning device 3.

Further, the membrane state diagnosing means 124 uses the feed water concentration Cf measured by the feed water conductivity meter 12, the feed water flow rate Qf measured by the feed water flow meter 13, and the feed water measured by the water temperature meter 10. Water temperature Tepm, permeated water flow rate Qp measured by permeated water flow meter 19, permeated water concentration Cp measured by permeated water conductivity meter 18, concentrated water pressure Pb measured by concentrated water pressure gauge 20, and my machine interface Membrane area F, number of modules N entered by operator via means 22
Based on r and the alarm generated in the system, fuzzy reasoning is used to correct the membrane state value using fuzzy reasoning, and fuzzy diagnostic means 34 for notifying the calculation is impossible, and eight items indicating the membrane state are octagonal. Of the polygonal diagnostic means 35 for recognizing the state of the film by observing the octagonal shape that changes due to the dirt and deterioration of the film, the input process value, and the film state value. Membrane state learning means 36 for learning the causal relationship using a neural network to improve the diagnostic accuracy of membrane fouling and deterioration, and the feed water pressure P measured by the feed water pressure gauge 11.
f, the optimum number of modules Nsv is obtained from the supplied water temperature Temp measured by the water temperature gauge 10, the permeated water flow rate target value Qsv input by the operator via the man-machine interface means 22 and the supply water pressure controllable range, and the operator is asked. Module number notification means 37 for notifying the optimum number of modules
And have.

Next, the operation of the embodiment having such a configuration will be described.

First, in the membrane state diagnosing means 124, the feed water pressure Pf measured by the feed water pressure gauge 11, the feed water flow rate Qf measured by the feed water flow meter 13, the feed water temperature Tepm measured by the water thermometer 10, and the feed water. Supply water concentration Cf measured by the conductivity meter 12, permeated water flow rate Qp measured by the permeated water flow meter,
The concentrated water pressure Pb measured by the concentrated water pressure gauge 20 and the membrane area F input by the operator via the man-machine interface means 122 are input. Next, in the water permeability coefficient diagnosing means 124a of the membrane state diagnosing means 124,
As shown in the diagnostic flow of FIG. 6, clogging and deterioration due to dirt on the membrane are diagnosed by the water permeability coefficient.

First, the water permeation coefficient Astd in the standard state showing the water production capacity is calculated using the equation (22) which is the transport equation of the reverse osmosis process. The membrane surface osmotic pressure πm of the equation (22) is obtained by using the equations (23), (24), and (25). The temperature correction coefficient At is expressed by the function (26) of the water temperature, but it is considered that the characteristics differ from site to site, and thus it is obtained by conducting an experiment for each site. Next, the calculated water permeation coefficient Astd is divided by the water permeation coefficient initial value A ₀ as shown in equation (27) to obtain the membrane state value S. If the film state value S is lower than the film fouling reference value (first reference value) α, it can be determined that the film is fouled. Further, S is a film deterioration reference value (second reference value)
If there is an increase above β, it is diagnosed that there is a risk of deterioration.
Further, if S is increased to the third reference value γ or more, it is determined that the operation is stopped and the plant is stopped.

After that, when the film state value is expressed by the equation (28) and the exponential function of FIG. 7, the parameter m that minimizes the error is obtained. If the obtained m falls below the reference value α ', it can be judged that the progress of the film fouling is fast. Also m
If is greater than the reference value β ′, it is diagnosed that the progress of deterioration is fast, and the time to reach the contamination limit is estimated. After making the above-mentioned diagnosis in the water permeability coefficient diagnosing means 124a,
The abnormality notifying means 123 notifies the operator of the abnormality, activates the reverse osmosis membrane cleaning apparatus 3, and stops the operation of the high-pressure pump 1 and the reverse osmosis membrane module 2.

At the initial stage of operation, the characteristics are grasped and the parameters are determined. In this case, check whether the conversion coefficient is a proper value.

[0118]

[Equation 11] Astd: Water permeation coefficient under standard conditions Qp: Permeate flow rate Pf: Supply water pressure Pb: Concentrated water pressure πm: Membrane surface osmotic pressure F: Unit membrane area At: A value temperature correction coefficient πm = kπ × Temp × Cm ... (23) Kπ: parameter Temp: water temperature Cm: film surface concentration

[0119]

(Equation 12) Sp: Salt exclusion rate RR: Recovery rate

[0120]

(Equation 13) Qf: Supply water flow rate At = f (Temp) (26)

[0121]

[Equation 14]

[0122]

(Equation 15) S: Membrane state value A ₀ : Initial water permeation coefficient (standard condition) m: Parameter t: Current time t ₀ : Membrane use start time Note that in FIG. 7, each point is obtained by the equation (27) and the curve Is calculated by equation (28).

Next, the operating module number determining means 125 detects the emergency stop command module and subtracts the emergency stop module number from the existing modules to determine the current operable module number according to the flow of FIG. Next, based on the supplied water temperature Temp measured by the water thermometer 10, the target treatment flow rate Qsv input by the operator through the man-machine interface means 122, and the operation policy, fresh water can be filled in the module and started up within 30 minutes. The number of modules Ns in a short-term storage state, and the number of modules Nl in a long-term storage state in which a chemical is filled in the module and it takes a long time to start up,
Determine the number of operating modules Nr.

In this case, target flow rate ≦ number of currently operable modules × module production capacity,

[0125]

[Equation 16] Number of short-term storage modules ≤ number of currently operable modules-number of operating modules, number of long-term storage modules = number of currently operable modules-number of operating modules-number of short-term storage modules.

As an operation policy, one module is always reserved and a short-term storage state is set.

Short-term storage is within 3 days, long-term storage is within 6 months, membrane replacement cycle is 3 years, and high-pressure pump inspection frequency is June (module stopped for 2 days).

Next, it is classified into a case where a long-term stop module and a short-term stop module can be secured (case 1), a case where only a short-term periodic module can be secured (case 2), and a case where there is no stop module (case 3).

Next, in the cleaning order determination means 26, the number of operating modules Nr, the number of short-term storage modules Ns, and the number of long-term storage modules Nl determined according to the flow of FIG. The order of low pressure cleaning and chemical cleaning is determined from the film state value S.

In FIG. 9, Case 1: When both long-term storage and short-term storage modules are available: -Module in which the progress of deterioration of the membrane is faster than the threshold-Module in which the degree of deterioration of the membrane exceeds the threshold-Comparison with elapsed time after low pressure cleaning A module whose membrane deterioration progresses rapidly, ・ A module whose membrane fouling progresses faster than the elapsed time after low-pressure cleaning, if there is a module that meets the above conditions, then perform chemical cleaning / long-term storage / inspection Keep it.

Also, a module that has passed the short-term storage period (3 days), a module in which the progress of deterioration of the membrane is faster than a threshold value, a module in which the degree of deterioration of the membrane exceeds the threshold value, and a progress rate of fouling of the membrane in a threshold value. Faster module ・ Membrane fouling exceeds the threshold value ・ Low pressure cleaning / short-term storage if there is a module satisfying the above conditions, otherwise maintain the current status.

Case 2: When there is no long-term storage module but only short-term storage module, -a module that has passed the short-term storage period (3 days),-a module in which the progress of deterioration of the membrane is faster than a threshold value, -the degree of deterioration of the membrane. Is above the threshold, ・ Module where the progress of membrane fouling is faster than the threshold, ・ Module where the degree of fouling of the membrane exceeds the threshold, if there is a module that meets the above conditions, low pressure cleaning / short-term storage, otherwise Keep it.

When a plurality of membrane modules to be cleaned are concentrated at the same time, the cleaning plan means 127 disperses the cleaning time from the past history of cleaning the film.

When a plurality of membrane modules to be cleaned are concentrated at the same time, the method of distributing the cleaning time by the cleaning planning means 127 is the same as the method of distributing the cleaning time shown in FIGS. 2 and 3.

That is, when the cleaning of each membrane module is concentrated based on the permeated water concentration Cp and the membrane cleaning range, the cleaning time is determined so that the preceding cleaning is performed with respect to the membrane state value set value. In this case, first, the membrane cleaning range ΔS is determined from the permeated water concentration Cp, the number of operating membrane modules Nr, and the permeated water flow rate Qp as follows.

If C ₁ ≦ Cp → ΔS = Sh if C ₁ > Cp → ΔS = Sl (29) C ₁ : Membrane cleaning range switching concentration set value Cp: Permeate concentration Sh: Membrane cleaning range Sl: Membrane cleaning Range d ₂ = Qp / Nr if C ₂ ≦ d ₂ → ΔS = Sh if C ₂ > d ₂ → ΔS = Sl (30) d ₂ : permeation flow rate per module C ₂ : membrane cleaning range switching concentration setting Values Based on the membrane cleaning range ΔS determined above, the cleaning time of the membrane module is determined as follows.

As shown in FIG. 2, the membrane cleaning range ΔS from the membrane module (i-1) pond having the lowest actual membrane state value.
The film state value S is divided for each (ΔS> 0), and the cleaning order is k, (k-1), (k-2), in ascending order of the film state value.
... The 1st (k: number of operating membrane modules) and the cleaning order are determined.

At this time, as shown in FIG. 2, there may be a case where the film state values of m pond are concentrated in a certain membrane cleaning range (No. 1 pond, 2
No. 3 and No. 3 ponds: m = 3), but in this order, the cleaning order 1 for each membrane module is the order with the longest operation duration (in the case of Fig. 2, the operation duration is 2nd pond> 1st pond). > The cleaning order is determined to be No. 3 pond), and the membrane module with the slowest cleaning order (3
As shown in FIG. 3, the membrane state value of each membrane module is corrected by ΔS as shown in FIG.

Si ′ = Si + (m−1) · ΔS (31) Si ′: Corrected virtual film state value of pond i Si: Actual film state value of pond i i m: Number of concentrated membrane modules l: order of cleaning within the membrane cleaning range If there is no membrane module whose actual membrane state value has reached the membrane state set value, if the calculated virtual membrane state has reached the membrane state set value, the membrane Outputs a cleaning request to the module. However, at this time, the lower limit value S _{L of the} film state at the start of cleaning is set for the film state value at the start of cleaning, and if the actual film state value is equal to or higher than this S _L , the cleaning request is output.

When there is a membrane module whose actual membrane state or actual operation duration has reached the membrane state setting value and the operation duration setting value, the cleaning request is output to the membrane module with the highest priority. However, when there are a plurality of reached membrane modules, the cleaning requests are output in order from the membrane module having the largest actual membrane state value.

Next, in the conductivity diagnostic means 128, the permeated water conductivity Cp measured by the permeated water conductivity meter 18 and the change rate ΔCp thereof are determined by the function of the water temperature and the reference value of the change rate. 10, the abnormality notification means 123 notifies the operator of the determination result shown in FIG. 10, and the membrane is cleaned, or the membrane is stopped or replaced.

In FIG. 10, the reference value of the conductivity determined by the function of the water temperature is

[0143]

[Equation 17]

[0144]

(Equation 18) Here, TDSp: permeated water conductivity Ktds: concentration / conductivity conversion coefficient Qs: permeated salt content Bstd: salt permeation coefficient.

Next, in the pressure diagnostic means 129, the supply water pressure Pf measured by the supply water pressure gauge 11 and its rate of change ΔP.
f, and the concentrated water pressure Pb measured by the concentrated water pressure gauge 20
When the change rate ΔPb is equal to or higher than the concentrated water pressure determined by the function of the water temperature and the reference value of the change rate, the abnormality notifying means 123 notifies the operator to wash the membrane.

In the differential pressure diagnostic means 130, the permeated concentrated pressure difference Pd, which is the difference between the permeated water pressure and the concentrated water pressure, is obtained by using the equation (34), and is the reference equation (35) for the permeated concentrated pressure difference Pd. If it is larger than the reference magnification, it is determined that the film is dirty, and the abnormality notification unit 123 notifies the operator to wash the film.

The reference formula (35) for the permeation concentration difference Pd is
We conduct experiments for each site and ask for it.

Pd = Pf−Pb (34) Pb: Concentrated water pressure Pd = f (Qp) (35) Next, in the ORP diagnostic means 131, the supply water ORP measured by the ORP meter 8 and its integration are calculated. If the value ORPinf is greater than or equal to each reference value, it is determined that there is a risk that the film will be oxidized and deteriorated, and the abnormality notifying means 123 notifies the operator to stop the operation of the film.

In the Ph diagnostic means 132, if the supply water pH measured by the pH meter 9 and its integrated value pHinf are above the respective reference values, there is a risk that hydroxide will precipitate and the membrane will be clogged. Then, the abnormality notification means 123 notifies the operator to stop the operation of the membrane.

Further, in the salt permeation coefficient diagnosis 133, the feed water concentration Cf measured by the feed water conductivity meter 12, the feed water flow rate Qf measured by the feed water flow meter 13, and the permeate flow meter 19 are measured. Permeate flow rate Qp and permeate conductivity meter 1
Based on the permeated water concentration Cp measured in 8 and the membrane area F input by the operator via the man-machine interface means 122, the salt permeation coefficient Bstd of the standard state reverse osmosis process is obtained. Next, the salt permeation coefficient Bstd is judged based on the reference value. If the salt permeation coefficient Bstd is equal to or less than the first reference value, the reverse osmosis membrane cleaning device 3 is activated, and if it is equal to or greater than the second reference value, the abnormality notifying means 123 is activated. , When the third reference value or more,
Stop driving.

The salt permeation coefficient Bstd in the standard state is calculated from the permeate concentration Cp, the feed water concentration Cf, and the feed water flow rate Qf using the equation (36) which is the transport equation of the reverse osmosis process. The temperature correction coefficient is obtained by the function (37) of the temperature characteristic. Since this temperature characteristic function is considered to be different for each site, it is obtained by conducting an experiment for each site.

The initial salt permeation coefficient B ₀ before the operation of the membrane and the salt permeation coefficient Bstd in the standard state are compared, and the membrane state value S is corrected based on the degree of increase in salt permeability, and the diagnostic accuracy of the membrane fouling and deterioration is improved. Improve. The comparative expression (38) is obtained by an experiment for each site.

[0153]

[Formula 19] Bstd: salt transmission coefficient in standard conditions Bt: B value temperature correction factor Bt = f (Temp) ...... ( 37) S '= S × f (Bstd, B 0) ...... (38) B 0: film pre-operation The initial salt permeability coefficient of the feed water conductivity meter 12
In the feed water concentration Cf, the feed water flow rate Qf measured by the feed water flow meter 13, the feed water temperature Temp measured by the water thermometer 10, and the permeate flow rate measured by the permeate flow meter 19. Qp, the permeated water concentration Cp measured by the permeated water conductivity meter 18, the concentrated water pressure Pb measured by the concentrated water pressure gauge 20, the module number Nr, and the man-machine interface means 22 are input by the operator. Based on the determined film area F and the alarm generated in the system, the following rule is used to correct the film state value by using fuzzy reasoning or notify the calculation failure.

Rule Example When a mechanical abnormality is detected by the process value sudden change check and the membrane condition diagnosis, the "condition of film contamination" and "deterioration of film" are not diagnosed by the film condition diagnosis.

When the abnormality of the instrument is detected and predicted by the membrane condition diagnosis, the "condition of the film fouling" and the "condition of the film deterioration" are not diagnosed.

When the number of modules is changed, the supply water pressure and the permeated water concentration are changed accordingly, so that the "membrane fouling condition" and "membrane deterioration condition" are not diagnosed.

When the membrane is not contaminated while the permeated water flow rate is constant, the feed water pressure and the permeated water concentration are in inverse proportion to each other.

Therefore, when the permeated water concentration is increased when the supply water pressure is increased, the membrane is dirty. On the contrary, if the permeate concentration also decreases when the feed water pressure decreases, the membrane is fouled.

If the water permeation coefficient converted to the current standard state is smaller than the water permeation coefficient in the initial state after water temperature conversion, the membrane is dirty.

When the B value is rising, the O ring is leaking when the A value and the supply water pressure are within a certain range. In addition, there is a risk of deterioration of the high-pressure pump and defective starting method of the high-pressure pump.

Further, in the polygon diagnosing means 35, as shown in FIG. 11, the man-machine interface means 122 is used to display the eight items indicating the state of the film so that the vertices of the octagon are axes, and the operator can Changes due to dirt and deterioration of membrane 8
Observe the prismatic shape so that the state of the membrane can be understood. The polygon diagnosing means 135 has only a display function and does not particularly output to another.

For example, when the octagonal shape changes in the direction of the dotted line, it can be determined that the film is clogged.

Further, when the octagonal shape is changed in the direction of the dotted line, if the peak of pH is extended, it can be determined that the pH has risen and hydroxide is precipitated and clogging. Further, if the peak of SDI is extended, it can be determined that SS in the supply water has risen and is clogged.

On the other hand, if the shape of the octagon changes in the direction opposite to the direction of the dotted line and if the apex of the ORP extends, it can be determined that the film has deteriorated due to oxidation.

Further, in the membrane state learning means 136, the raw water condition and the operating condition of the supplied water SDI and the supplied water ORP.
, Supply water pH, supply water pressure Pf, supply water flow rate Qf
, Supply water concentration Cf, water temperature Temp, and permeate flow rate Q
p, permeated water concentration Cp, concentrated water pressure Pb, differential pressure Pd between supply water pressure Pf and concentrated water pressure Pb, weather information, and time series data of the membrane area F for a certain period are input to the neural network. . Input is repeated at regular intervals.

When the input is accumulated, the causal relation between the condition of the raw water and the state of the membrane is learned by the back propagation method using the membrane state value S as a teacher signal. By repeating this learning, it becomes possible to grasp the contamination of the film and the deterioration factor item. The learning result is notified to the operator, and the newly found relationship is added as a rule to the fuzzy diagnostic means 134 and reflected in the membrane condition diagnostic means 124 to improve the accuracy of the membrane condition diagnosis.

In the module number notifying means 37, the supply water pressure Pf, the supply water temperature Temp, and the supply water flow rate Q.
f, the permeated water flow rate Qp, the concentrated water pressure Pb, the permeated water flow rate target value Qsv input by the operator through the man-machine interface means 22, and the supply water pressure upper limit value Pfmax.
Based on and, the minimum number of modules Nrmin is calculated by the equations (39) and (40).

Further, the difference between the current operating cost and the operating cost with the minimum number of modules is obtained from the equation (41), and the operator is notified via the man-machine interface means 122. Cost per module Since the cost function per module operation differs from site to site, the function is calculated for each site. Module number notification means 37
Does not output to any other.

[0169]

(Equation 20) Apv: Water permeation coefficient under use conditions Pfmax: Upper limit of supply water pressure Funit: Membrane area per module

[0170]

[Equation 21] ΔCost = f (Nr) −f (Nrmin) (41) In a desalination apparatus having a reverse osmosis membrane module, the amount of permeated salt increases as the water temperature rises. Even if the membrane deteriorates, the amount of permeated salt increases. Will increase. Conventionally, it has been attempted to monitor the amount of permeated salt to diagnose membrane fouling, but it is not possible to detect early whether the increase in the amount of permeated salt is due to an increase in water temperature or deterioration of the membrane. However, there were cases where the replacement of the membrane was delayed or, conversely, the usable membrane was replaced. Also,
It has been considered to replace the membrane regularly because of fear of an accident due to deterioration of the membrane, but sometimes the usable membrane was replaced. As described above, it has been impossible to make the most effective use of the expensive membrane by monitoring the amount of permeated salt in the related art or periodically exchanging the membrane.

However, according to the present embodiment, the state of the membrane can be expressed by the state value S by the membrane state diagnosing means 124, it can be judged that the membrane is clogged when S is decreased and the membrane is deteriorated when S is increased. Therefore, the operation according to the state of the film can be performed. In addition, the operating module number determining means 125, the cleaning order determining means 126, and the cleaning planning means 127 determine an appropriate order,
Low-pressure cleaning / short-term stopping of membranes, chemical cleaning / long-term stopping,
Exchanges can be made.

Although the life of the membrane is prolonged by an appropriate operation, the reverse osmosis membrane is expensive, so the life of the membrane can reduce the operating cost. Further, by performing an appropriate operation by the operation control device 121, it is possible to reduce the burden on the operator.

Further, the water producing apparatus having the reverse osmosis membrane module has a property that the amount of permeated water increases with an increase in the water temperature, and is also proportional to the supply water pressure. Conventionally, in order to obtain a certain amount of water from a fresh water generator, the supply water pressure is reduced when the water temperature rises, or the number of operating membrane modules is changed about once a year. The increase in the capacity of the fresh water generator with a rise in the water temperature is remarkable, and in this embodiment, by utilizing this property, the operating cost can be reduced by changing the number of operating modules. Further, when changing the number of membrane modules to be operated, it is possible to perform a more efficient operation by selectively suspending and cleaning the membrane that is contaminated or deteriorated. Efficient operation was difficult because the number of membrane modules was not changed significantly. However, according to the present embodiment, the module number notifying means 137 can notify the operator of the economical number of membrane modules, so that the number of operating modules can be changed according to the stop time.

[0174]

As described above, according to the first aspect of the present invention, the membrane condition diagnosing means diagnoses dirt and deterioration of the reverse osmosis membrane module, and the reverse osmosis membrane module can be washed and inspected at an appropriate time. Therefore, it is possible to prolong the life of the membrane and continuously produce a target amount of high-quality permeate. Further, since it becomes possible to detect abnormalities in the reverse osmosis membrane module at an early stage, fatal membrane fouling and damage can be prevented, and the life of the membrane can be extended. Further, since an abnormality of the reverse osmosis membrane module can be notified to the operator, it contributes to the operator's understanding of the process state and enables efficient and safe operation.

According to the second aspect of the present invention, even if the water permeation coefficient fluctuates, the cleaning device or the abnormality notifying means is not unnecessarily operated if the water permeation coefficient returns within a predetermined short time. Therefore, unnecessary false alarm or malfunction can be prevented.

According to the third aspect of the present invention, since the membrane fouling is not diagnosed when the module fluctuates to disturb the membrane fouling diagnosis, it is possible to prevent unnecessary false alarm or malfunction.

According to the fourth aspect of the present invention, the membrane state value can be corrected according to the actual situation by the intermembrane concentration and the amount of permeated salt. Therefore, highly accurate operation control can be performed.

According to the fifth aspect of the present invention, since the water permeation coefficient and the salt permeation coefficient are corrected based on the number of operating modules, it is possible to further perform operational control in accordance with the actual situation.

According to the invention described in claim 6, the state value of the plant is used as an input signal according to the learning state of the membrane state, the state value of the plant is used as a teacher signal by the neural network, and the causal relation between the state value of the plant and the membrane state value is determined. By learning, the membrane state value can be obtained with high accuracy in accordance with the actual situation of the plant, and thus accurate operation control can be performed.

According to the invention described in claim 7, the reverse osmosis membrane module to be cleaned can be prevented from concentrating at the same time by the membrane cleaning planning means. Therefore, it is possible to disperse the amount of washing water used by the washing device and perform an appropriate washing action.

According to the eighth aspect of the invention, the number of operating modules is determined from the supply water pressure and the supply water temperature by the module number determining means, and the membrane module to be operated is determined by the module operation planning means. Thereby, a plurality of membrane modules can be used in good balance.

According to the invention described in claim 9, deterioration of the membrane and clogging can be detected by the diagnosis of the reverse osmosis membrane based on the water permeation coefficient, and cleaning and inspection can be performed at an appropriate time.
It is possible to continuously produce a target amount of high quality permeate. Furthermore, since it becomes possible to detect abnormalities at an early stage, it contributes to prolonging the life of the membrane in the sense that fatal membrane fouling can be prevented. Since the information on the film state can be notified to the operator, it contributes to the operator's grasp of the process state and enables efficient and safe operation. It also promotes work efficiency. Since reverse osmosis membranes are expensive, prolonging the life of the membranes reduces operating costs.

According to the tenth aspect of the present invention, when cleaning each membrane module, the cleaning interval of the membrane module is appropriate according to the operation policy input by the operator, the permeated water concentration, the permeated water flow rate, and the number of operating modules. Therefore, when the cleaning of each membrane module is concentrated, the cleaning is dispersed so as to perform the preceding cleaning with respect to the set membrane state value, so that the cleaning can be performed before the set membrane state is exceeded. Efficient operation is possible without burdening the vehicle.
Furthermore, the membrane module that can be selectively operated can be prepared according to the policy input by the operator, so that the membrane can be exchanged systematically. The cost can be reduced because the expensive membrane can be replaced systematically.

According to the eleventh aspect of the invention, the deterioration of the film can be detected earlier by incorporating the conductivity information into the condition diagnosis of the film. In addition, the accuracy of the stain diagnosis can be improved.

According to the twelfth aspect of the present invention, the clogging of the film can be detected earlier by incorporating the pressure information into the condition diagnosis of the film. In addition, the accuracy of machine diagnosis can be improved.

According to the thirteenth aspect of the invention, the deterioration of the film can be detected earlier by incorporating the ORP information in the film state diagnosis.

According to the fourteenth aspect of the present invention, the clogging of the membrane can be detected earlier by incorporating the pH information into the state diagnosis of the membrane.

According to the fifteenth aspect of the present invention, by diagnosing the state of the membrane by the salt permeation coefficient, it becomes possible to detect the clogging state of the membrane earlier and finely.

According to the sixteenth aspect of the invention, since the state of the film is visually displayed, the state of the film can be grasped intuitively and easily. Not only can the shape of the displayed graphic be used to determine whether the film is clogged or deteriorated, but also the factors can be estimated.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an operation control device for a fresh water plant according to the present invention.

FIG. 2 is a diagram for explaining the operation of the cleaning planning means of the membrane module.

FIG. 3 is a diagram for explaining the operation of the cleaning planning means of the membrane module.

FIG. 4 is a configuration diagram showing a second embodiment of an operation control device for a fresh water plant according to the present invention.

FIG. 5 is a block diagram showing details of a membrane state diagnosis means.

FIG. 6 is a flow chart of a membrane state diagnosis means.

FIG. 7 is a simulated graph showing a time series change of the film state value S.

FIG. 8 is a flow chart for determining the number of modules.

FIG. 9 is a flow diagram for determining a wash / stop module.

FIG. 10 is a diagram showing a matrix of conductivity diagnosis.

FIG. 11 is a view showing a polygon displayed by a polygon state diagnosis means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-pressure pump 2 Reverse osmosis membrane module 3 Cleaning device 21 Operation control device 22 Fuzzy inference means 23 Membrane condition diagnosis means 24 Membrane condition display means 25 Cleaning confirmation means 26 Membrane cleaning means 27 Abnormality notification means 28 Membrane condition learning means 29 Membrane cleaning plan Means 30 Module number determination means 31 Appropriate module number display means 32 Module number change confirmation means 33 Module number change means 34 Module operation planning means 35 Overall planning means 36 Man-machine interface means 121 Operation control device 122 Man-machine interface means 123 Abnormality notification means 124 Membrane State Control Means 124a Water Permeability Coefficient Diagnostic Means 125 Operating Module Number Determining Means 126 Cleaning Order Determining Means 127 Cleaning Planning Means 128 Conductivity Diagnostic Means 129 Pressure Diagnostic Means 130 Differential Pressure Diagnostic Means 131 OR P diagnostic means 132 pH diagnostic means 133 Salt permeation coefficient diagnostic means 134 Fuzzy diagnostic means 135 Polygonal diagnostic means

Claims (16)

[Claims] 1. A reverse osmosis membrane module for desalting through supply water to obtain permeated water and for converting impervious water into concentrated water, and a cleaning device for regularly cleaning the reverse osmosis membrane module.
In the operation control device of the fresh water plant having a measuring unit for measuring the state value of the plant, an abnormality notifying unit for notifying the plant abnormality, the supply water pressure measured by the measuring unit, the supply water side of the reverse osmosis membrane module The water permeation coefficient of the reverse osmosis process was calculated from the following formula based on the membrane surface osmotic pressure and the permeated water flow rate. The membrane state value obtained by subtracting the initial value from this water permeability coefficient is
When the film thickness is below the first reference value, it is diagnosed that the film is dirty and the cleaning device is operated, and when it is above the second reference value, the film deterioration is diagnosed and the abnormality notifying unit is operated. An operation control device for a desalination plant, comprising: 2. The membrane condition diagnosing means does not diagnose membrane fouling if the value obtained by subtracting the initial value from the water permeation coefficient is less than or equal to the first reference value, but recovers within a predetermined time, and The operation control device for a desalination plant according to claim 1, further comprising fuzzy inference means that does not diagnose deterioration of the membrane if the film is recovered within a predetermined time even if it is equal to or more than the second reference value. 3. The fuzzy inference means further diagnoses the membrane flow based on the feed water pressure and the permeate concentration, and
The membrane diagnosis is not performed when the number of input reverse osmosis membrane modules varies.
The operation control device of the desalination plant described. 4. The membrane condition diagnosing means further receives the permeated water concentration, the supplied water concentration and the supplied water flow rate measured by the measuring means, and outputs the permeated water concentration, the supplied water concentration, the permeated water flow rate and the supplied water flow rate. It is characterized in that the inter-membrane concentration is obtained based on it, the permeated salt content is obtained from the permeated water concentration and the feed water concentration, and the membrane state value is corrected by the salt permeation coefficient obtained from this inter-membrane concentration and permeated salt content. The operation control device of the desalination plant according to claim 1. 5. The operation control of a desalination plant according to claim 4, wherein the membrane condition diagnosing means corrects the water permeation coefficient and the salt permeation coefficient based on the input operation module number of the reverse osmosis membrane module. apparatus. 6. A membrane state diagnosing means has a built-in neural network capable of learning a causal relationship for obtaining a membrane state value from a plant state value, using the plant state value as an input signal and the membrane state value as a teacher signal. The operation control device for a fresh water plant according to any one of claims 1 to 5, further comprising a state learning unit. 7. A plurality of reverse osmosis membrane module devices are provided, wherein the order of washing is determined in the order of the reverse osmosis membrane modules which are diagnosed by the membrane state diagnosing means as having a soiled membrane, and the plurality of membrane modules to be washed are the same. When the concentration is concentrated in a certain period, it further comprises a membrane cleaning planning means for dispersing the cleaning time so that other membrane modules are cleaned earlier by a predetermined time based on the membrane module having the latest cleaning sequence among them. The operation control device of the desalination plant according to claim 1. 8. A plurality of reverse osmosis membrane module devices are provided, and a module number determining means for determining an appropriate number of operating modules from the supply water pressure and the water temperature of the supply water, and a signal from this module number determining means and a past signal. The operation control device of the desalination plant according to claim 1, further comprising a module operation planning unit that determines which membrane module is operated based on an operation history of each module. 9. A reverse osmosis membrane module for desalting through supply water to obtain permeated water and for converting impervious water into concentrated water, and a cleaning device for regularly cleaning the reverse osmosis membrane module.
In the operation control device of the desalination plant having a measuring unit for measuring the state value of the plant, an abnormality notifying unit for notifying an abnormality of the plant, and the supply water pressure, the supply water temperature, and the supply water concentration measured by the measuring unit. , The permeated water flow rate, the concentrated water pressure, and the membrane area input from the outside, the water permeation coefficient of the reverse osmosis process was calculated from the following equation: A value obtained by dividing the water permeation coefficient by the initial value is taken as a membrane state value, and when the membrane state value is equal to or less than the first reference value, it is determined that the membrane is dirty and the cleaning device is operated to A membrane condition diagnosing means for deciding that the membrane is deteriorated when it is equal to or more than 2 reference values and activating the abnormality notifying means, and stopping the operation of the plant when it is equal to or more than the third reference value. An operation control device for a desalination plant, which is characterized in that 10. A plurality of reverse osmosis membrane modules are provided, and the number of modules in a short-term storage state and long-term storage are possible based on the water temperature measured by the measuring means, the target treatment flow rate input from the outside, and the operation policy. Output from the module for determining the number of operating modules that determines the number of modules in the long-term storage state and the number of operating modules, the number of operating modules from the number of operating module determination, the number of short-term storage modules and the long-term storage module, and the membrane state diagnostic means When the cleaning order determining means that determines the order of low pressure cleaning and chemical cleaning based on the measured membrane state value and a plurality of membrane modules to be cleaned are concentrated at the same time,
Based on the history of cleaning membranes in the past, the membrane module with the slowest cleaning sequence among these is used as a reference, and a cleaning planning means for dispersing the cleaning time so that other membrane modules are cleaned earlier by a predetermined time. The operation control device for a desalination plant according to claim 9. 11. The membrane condition diagnosing means judges that the membrane is dirty when the permeated water conductivity and its rate of change measured by the measuring means are below respective lower limit reference values determined by a function of water temperature. In addition to prompting the membrane to be washed, if the permeated water conductivity and its change rate are above the respective upper limit reference values determined by the water temperature function, it is judged that the membrane has deteriorated and the membrane should be stopped and replaced. The operation control device for a desalination plant according to claim 9, further comprising a stimulating conductivity diagnostic means. 12. The membrane condition diagnosing means is a membrane when the supply water pressure and its rate of change measured by the measuring means, and the concentrated water pressure and its rate of change are each reference values determined by a function of water temperature or more. It is judged that the membrane is dirty and the pressure diagnostic means that prompts the membrane to be washed, and when the pressure difference between the supply water pressure and the concentrated water pressure is more than the reference value determined by the function of the permeate flow rate, the membrane is dirty. 10. The operation control device for a desalination plant according to claim 9, further comprising: a differential pressure diagnostic means for accelerating the cleaning of the membrane. 13. The membrane state diagnosing means activates the abnormality notifying means by activating the abnormality notifying means when the ORP and ORP integrated values of the supply water measured by the measuring means are equal to or larger than the respective reference values. The operation control device for a desalination plant according to claim 9, further comprising a diagnostic means. 14. The membrane condition diagnosing means, if the feed water pH and the pH integrated value measured by the measuring means are equal to or higher than the respective reference values, there is a risk that hydroxide may precipitate and the membrane may be clogged.
The operation control device for a desalination plant according to claim 9, further comprising pH diagnosing means for activating the abnormality notifying means. 15. The membrane condition diagnosing means reverse osmosis based on the feed water concentration, the feed water flow rate, the feed water temperature, the permeate flow rate, the permeate concentration measured by the measuring means, and the membrane area input from the outside. The salt permeation coefficient of the process was calculated from the following formula, and If the salt permeation coefficient is less than or equal to the first reference value, it is determined that the membrane is dirty and the cleaning device is activated. If it is greater than or equal to the second reference value, it is determined that the membrane is deteriorated. The operation control device for a desalination plant according to claim 9, further comprising salt permeation coefficient diagnosis means for activating the abnormality notifying means and stopping the operation when the value is equal to or more than the third reference value. 16. The membrane state diagnosing means comprises a feed water pH, a feed water SDI, a feed water ORP, a water permeation coefficient, a salt permeation coefficient, a desalination rate calculated from the permeate concentration and the feed water concentration, which are measured by the measuring means. Each item indicating the state of the membrane consisting of the difference between the supply water pressure and the concentrated water pressure and the difference between the supply water pressure target value and the process value is displayed with the vertex of the polygon as the axis, and The operation control device for a water desalination plant according to claim 9, further comprising polygonal diagnosis means for observing a state of the membrane by observing a polygonal shape that changes due to deterioration.