CN113499690A - High-pressure membrane filtration system and recovery rate control and protection method - Google Patents

High-pressure membrane filtration system and recovery rate control and protection method Download PDF

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Publication number
CN113499690A
CN113499690A CN202110855522.XA CN202110855522A CN113499690A CN 113499690 A CN113499690 A CN 113499690A CN 202110855522 A CN202110855522 A CN 202110855522A CN 113499690 A CN113499690 A CN 113499690A
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pressure
value
regulating valve
recovery rate
opening
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陈明
谭金宝
王群保
武克亮
关晓琳
王怀林
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Jiangsu Kaimi Membrane Technology Co ltd
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Jiangsu Kaimi Membrane Technology Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/027—Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/08—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/10—Accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/12—Controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/147—Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/18—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/20—Accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/22—Controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/14—Pressure control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/16—Flow or flux control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/25—Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed

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  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nanotechnology (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention discloses a high-pressure membrane filtration system and a recovery rate control and protection method, wherein the membrane filtration system comprises at least one membrane component, a high-pressure pump, a circulating pump, a raw water pipeline, a concentrated water pipeline, a high-pressure regulating valve and a PLC (programmable logic controller), the high-pressure pump is arranged on the raw water pipeline, a water inlet flow meter is arranged on the raw water pipeline, a pressure transmitter S1 is arranged at the inlet end of the membrane component, a pressure transmitter S2 is arranged at the outlet end of the membrane component, the circulating pump is arranged on the concentrated water pipeline, the high-pressure regulating valve and the concentrated water flow meter are arranged on the concentrated water pipeline, the high-pressure pump, the water inlet flow meter, the concentrated water flow meter, the pressure transmitter and the high-pressure regulating valve are all connected with the PLC, and the PLC performs recovery rate control and linkage protection on the system according to the recovery rate H and the transmembrane pressure difference K. The invention utilizes the fuzzy control method to control the recovery rate of the system, can eliminate the frequent switching phenomenon of the high-pressure regulating valve, ensures the stable operation of the membrane filtration system, and improves the recovery rate and the filtration quality of the system.

Description

High-pressure membrane filtration system and recovery rate control and protection method
Technical Field
The invention relates to the technical field of membrane filtration, in particular to a high-pressure membrane filtration system and a recovery rate control and protection method.
Background
Membrane filtration is a membrane separation technique using pressure as a driving force, also called membrane filtration technique, which is an advanced means for water treatment, and can be classified into Reverse Osmosis (RO), Nanofiltration (NF), Ultrafiltration (UF), Microfiltration (MF), and the like, depending on the membrane selectivity.
The system recovery rate is an important index for evaluating the working efficiency of a membrane filtration system, the control of the system recovery rate is closely related to the system pressure, and the existing high-pressure membrane filtration system generally adjusts the system pressure by adjusting the opening of a high-pressure adjusting valve, so that the system recovery rate is controlled, the opening of the high-pressure adjusting valve is increased, the flow of concentrated water is increased, the system pressure is reduced, and the system recovery rate is reduced; the opening degree of the high-pressure regulating valve is reduced, the flow of concentrated water is reduced, the pressure of the system is increased, and the recovery rate of the system is increased.
The existing high-pressure regulating valves all adopt needle valves, and due to the small valve caliber and short stroke, the valve is switched on or switched off or regulated at an excessively high speed, so that the system pressure rises excessively fast or descends at an excessively high speed in the valve regulating process. The opening degree of the existing high-pressure regulating valve is generally regulated by adopting a PID regulating mode, and in the actual operation process, because the pressure of a high-pressure system rises or falls slowly, the instrument reaction is slow, the system pressure cannot be fed back in real time, and frequent switching of the high-pressure regulating valve often occurs, so that the pressure and the recovery rate of a membrane filtration system fluctuate frequently, even the system pressure exceeds a safety value due to the fact that the high-pressure regulating valve is closed too fast, and safety risk exists; frequent fluctuation of the pressure and the recovery rate of the membrane filtration system not only affects the filtration performance and the service life of the membrane, but also reduces the filtration quality of the membrane and the recovery rate of the system. Therefore, the design of a safe, practical and stably-operating high-pressure membrane filtration system and a recovery rate control and protection method has important significance.
Disclosure of Invention
In order to achieve the purpose, the invention provides a high-pressure membrane filtration system and a recovery rate control and protection method.
The technical scheme adopted by the invention is as follows:
a high-pressure membrane filtration system comprises at least one membrane component, a high-pressure pump, a circulating pump, a raw water pipeline, a concentrated water pipeline and a PLC (programmable logic controller), wherein the high-pressure pump is arranged on the raw water pipeline and used for inputting filtered raw water to the membrane filtration system, a water inlet flow meter used for detecting water inlet flow is arranged at the inlet end of the high-pressure pump, a pressure transmitter S1 used for detecting the water inlet pressure of the membrane component is arranged at the inlet end of the membrane component, a pressure transmitter S2 used for detecting the concentrated water outlet pressure of the membrane component is arranged at the outlet end of the membrane component, the circulating pump is arranged on the concentrated water pipeline at the outlet of the membrane component and used for inputting concentrated water generated by the membrane component to a next membrane component or a next process, a high-pressure regulating valve is arranged at the concentrated water outlet end of the membrane filtration system, a concentrated water flow meter used for detecting the water outlet flow of the concentrated water is arranged at the outlet end of the high-pressure regulating valve, the high-pressure pump, the water inlet flow meter, the concentrated water flow meter and the high-pressure meter, The concentrated water flowmeter, the pressure transmitter and the high-pressure regulating valve are all connected with a PLC (programmable logic controller), and the PLC controls the recovery rate of the system according to the recovery rate H of the system; performing chain protection on the system according to the transmembrane pressure difference K;
the transmembrane pressure difference K is max (P)2-P1) The system recovery rate H ═ F1-F2)/F1X is 100%; wherein the content of the first and second substances,
P1the water inlet pressure value of the membrane component detected by the pressure transmitter S1;
P2the membrane module effluent pressure value detected by the pressure transmitter S2;
F1the water inlet flow value of the high-pressure membrane filtration system is detected by a water inlet flowmeter;
F2the value of the concentrated water outlet flow of the high-pressure membrane filtration system is detected by the concentrated water flowmeter.
When the system recovery rate has negative deviation and the negative deviation of the recovery rate exceeds the allowable deviation range, closing the valve according to the step of closing the regulating valve; when the system recovery rate has positive deviation and the positive deviation of the recovery rate exceeds the allowable deviation range, the valve is opened according to the opening step of the regulating valve until the system recovery rate is within the allowable deviation range, and the regulation is stopped.
Further, the regulating valve closing step includes:
firstly, rapidly closing an adjusting valve to an initial opening degree;
secondly, after the regulating valve is quickly closed to the initial opening, closing actions are alternately executed according to the gain value and the pulse time, namely, after the opening of the regulating valve reaches one gain value, the pulse time is executed once, and after the pulse time is finished, the closing actions are continuously executed according to a second gain value;
thirdly, repeating the second step until the recovery rate of the system is within the allowable deviation range, and stopping closing action;
the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to a reduced value of the valve opening; the pulse time refers to the stop time between the two closing actions of the high-pressure regulating valve which is executed in a segmented mode in the closing process.
Further, the gain value is a percentage value of the reduction of the valve opening.
Further, the regulating valve opening step includes:
the method comprises the following steps that firstly, opening actions are alternately executed according to gain values and pulse time, namely, after the opening degree of an adjusting valve reaches one gain value, the pulse time is executed once, and after the pulse time is finished once, the opening actions are continuously executed according to a second gain value;
step two, repeating the step one until the regulating valve is opened to the initial opening degree;
thirdly, after the regulating valve is opened to the initial opening degree, the regulating valve is quickly opened until the regulating valve is fully opened;
the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to an increase value of the valve opening; the pulse time refers to the stop time between the two opening actions of the high-pressure regulating valve which is opened in a segmented manner.
Further, the gain value is a percentage value of the increase of the valve opening.
A method for protecting the high-pressure membrane filtration system comprises the following steps: the method comprises the following steps: when any one of a high-pressure protection value, a flow protection value, a membrane flux protection value or a transmembrane pressure difference protection value of the system reaches a set value, opening a valve according to a starting step of a regulating valve, and reducing the operating pressure of the system in time;
the set value of the high-voltage protection value is as follows: p2Greater than or equal to the design pressure multiplied by 120 percent;
the set value of the flow protection value is as follows: f2Less than or equal to the design concentrated water flow value multiplied by 50 percent;
the set values of the membrane flux protection values are: f1-F2) More than or equal to (design inflow flow value-design concentrated water flow value) multiplied by 120 percent;
the set value of the transmembrane pressure difference protection value is as follows: k is larger than or equal to the maximum transmembrane pressure difference value which can be borne by a membrane module designed by the system.
Further, the regulating valve opening step includes:
the first step is as follows: the second step is executed after the instrument signal continuously exceeds the set response time;
step two, alternately executing opening action according to the gain value and the pulse time, namely executing the pulse time once after the opening degree of the regulating valve reaches one gain value, and continuing executing the opening action according to the second gain value after the pulse time is finished;
thirdly, repeating the first step until the regulating valve is opened to the initial opening degree;
fourthly, after the regulating valve is opened to the initial opening degree, the regulating valve is quickly opened until the regulating valve is fully opened;
the response time refers to the time that the system instrument signal is stable continuously at a value; the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to an increase value of the valve opening; the pulse time refers to the stop time between the two opening actions of the high-pressure regulating valve which is opened in a segmented manner.
Further, the step of immediately stopping the high pressure pump is performed in parallel.
The invention has the beneficial effects that:
1. by setting parameters such as 'deviation of recovery rate', 'gain value', 'response time', 'initial opening' and the like, the system is subjected to recovery rate control by using a fuzzy control method, the phenomenon that the high-pressure regulating valve is frequently opened and closed can be eliminated, the stable operation of the membrane filtration system is ensured, the recovery rate and the filtration quality of the system are improved, and the service lives of the membrane and the high-pressure regulating valve are prolonged.
2. The high-pressure regulating valve and the high-pressure pump are controlled in an interlocking manner by setting parameters such as a high-pressure protection value, a flow protection value and a transmembrane pressure difference protection value, so that the safety and stability of the operation of the high-pressure membrane system are ensured.
Drawings
Fig. 1 is a schematic configuration diagram of a high pressure membrane filtration system according to a first embodiment of the present invention.
Detailed Description
In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.
In the following examples:
water inlet pressure value P of membrane module1: and (4) detecting the water inlet pressure value of the membrane assembly by the pressure transmitter S1.
Membrane module water outlet pressure value P2: membrane module effluent pressure detected by pressure transmitter S2And (4) force value.
Transmembrane pressure difference K ═ max (P)2-P1)。
Opening degree D of the valve: refers to the degree of valve opening, typically expressed as a percentage, with 0 indicating full closure.
Initial opening D0: the valve opening degree of the high-pressure regulating valve is defined when the system pressure is less than 4 bar.
Gain value DZ: refers to an increase or decrease in the valve opening D.
Flow rate of inflow F1: and the water inlet flow meter F1 detects the water inlet flow of the high-pressure membrane filtration system.
Flow value F of concentrated water2: and the concentrated water flow meter F2 detects the outlet flow of the concentrated water of the high-pressure membrane filtration system.
Actual recovery rate HS：＝(F1-F2)/F1×100％。
Target recovery rate HM: refers to the design recovery rate of the system, and the value can be adjusted according to the actual requirement.
Deviation of recovery HP ═ actual recovery HSTarget recovery HM。
Time of pulse SM: the high-pressure regulating valve performs closing or opening actions in a segmented mode in the closing or opening process, and the stop time between the two closing or opening actions is the pulse time.
Response time: which refers to the time that the system meter signal is stable at a value.
Setting value of high voltage protection value: p2Greater than or equal to the design pressure x 120% and this value can be modified as required to prevent the risk of membrane system overpressurization.
Set value of flow protection value: f2Less than or equal to the designed concentrated water flow value multiplied by 50 percent, is used for preventing the risk brought by the overpressure operation of the membrane system and the safe redundant protection of the membrane system.
Set value of membrane flux protection value: (F)1-F2) Is greater than or equal to (designed inflow water flow value-designed concentrated water flow value) x 120 percent and is used for preventing membrane flux from being too large to cause membrane component damageThe risk of (c).
Set value of transmembrane pressure difference protection value: k is larger than or equal to the maximum transmembrane pressure difference value which can be borne by a membrane module designed by the system.
Embodiment mode 1
Referring to fig. 1, the present embodiment provides a high pressure membrane filtration system, including at least one membrane module M1, a high pressure pump P1, a circulation pump P2, a raw water pipeline, a concentrated water pipeline and a PLC controller, where the high pressure pump P1 is disposed on the raw water pipeline for inputting high pressure filtered raw water to the membrane filtration system, an inlet end of the high pressure pump P1 is provided with a water inlet flow meter F1 for detecting a water inlet flow rate, an inlet end of the membrane module M1 is provided with a pressure transmitter S1 for detecting a water inlet pressure of the membrane module M1, an outlet end of the membrane module M1 is provided with a pressure transmitter S2 for detecting a concentrated water outlet pressure of the membrane module M1, the circulation pump P2 is disposed on a concentrated water pipeline at an outlet of the membrane module M1 for inputting concentrated water generated by the membrane module M1 to a next membrane module M1 or a next process, a concentrated water outlet end of the membrane filtration system is provided with a high pressure regulating valve VS1, an outlet end of the high pressure regulating valve VS1 is provided with a water flow meter F2 for detecting a concentrated water outlet flow rate, the high-pressure pump P1, the water inlet flowmeter F1, the concentrated water flowmeter F2, the pressure transmitter S1, the pressure transmitter S2 and the high-pressure regulating valve VS1 are all connected with a PLC controller, and the PLC controls the recovery rate of the system according to the recovery rate H of the system; and performing chain protection on the system according to the transmembrane pressure difference K.
Preferably, the inflow meter F1 and the concentrate flow meter F2 are electromagnetic flow meters or rotary wheel flow meters; pressure transmitter S1 and pressure transmitter S2 are static pressure transmitters.
In this embodiment, two membrane modules M1 are provided, the concentrated water of the first membrane module M1 is pumped into the second membrane module M1 by the first high-pressure pump P1, and the concentrated water of the second membrane module M1 is pumped into the next process by the second high-pressure pump P1.
The design parameters and process operating parameters of the high-pressure membrane filtration system described in example 1 were:
target recovery rate HM70% allowable negative deviation HP of recovery-At-5%, the permissible positive deviation HP of the recovery+Is + 5%;
the valve opening D is fully opened when being 90 percent, and the initial opening D of the valve060% gain value DZIs 1%;
the pulse time is 1 second, and the response time is 5 seconds;
the working pressure is 80bar, and the set value of the high-pressure protection value is as follows: p296bar or more;
the set values for transmembrane pressure difference protection were set as: k is more than or equal to 10 bar;
design inlet flow value FJIs 10m3H, designing the flow value F of concentrated waternIs 3m3H, set value of flow protection value: f2Less than or equal to 1.5m3H, set value of membrane flux protection value: (F)1-F2) Greater than or equal to 8.4m3/h。
Embodiment mode 2
When the PIC detects the negative deviation HP of the system recovery rate-When the signal duration response time is more than-5% for 5s, the PIC control regulating valve is closed according to the following steps:
firstly, rapidly closing an adjusting valve to 60% of an initial opening degree;
secondly, after the regulating valve is quickly closed to 60% of opening degree, the PIC controls the regulating valve to be slowly closed to 59% of opening degree according to a first gain value of minus 1%, then the closing action is stopped for 1 second, the closing action of the next gain value of minus 1% is executed, and therefore the closing action is alternately executed according to the gain value of minus 1% and the pulse time of 1 second;
the PIC monitors the system recovery in real time during the closing of the regulating valve until a negative deviation HP of the system recovery is detected-When the temperature is within the allowable range, the closing operation is stopped.
When positive recovery bias HP is detected by PIC+When the response time is more than 5% and the signal lasts for 5s, the PIC controls the regulating valve to be opened according to the following steps:
step one, alternately executing opening action according to a gain value of + 1% and a pulse time of 1 second, namely stopping the opening action for 1 second after the opening degree of the regulating valve reaches a gain value of + 1%, and then executing the opening action according to a second gain value of + 1% until the regulating valve is opened to an initial opening degree of 60%;
thirdly, after the regulating valve is opened to 60 percent of opening degree, the regulating valve is quickly opened to 90 percent of full degree;
the PIC monitors the system recovery in real time during the opening of the regulating valve until a positive deviation HP of the system recovery is detected+When the opening is within the allowable range, the opening operation is stopped.
Embodiment 3
A method of protecting a high pressure membrane filtration system as described in example 1 when P is detected by the PIC2Not less than 96bar or (F)1-F2)≥8.4m3H or F2≤1.5m3When the pressure/h or the pressure K is more than or equal to 10bar, opening a valve according to the following steps and stopping the system;
the first step is as follows: after the high-pressure regulating valve receives a signal of continuously responding to the opening for 5 seconds, executing a second step;
secondly, alternately executing opening action according to the gain value + 1% and the pulse time of 1 second, namely stopping the opening action for 1 second after the opening degree of the regulating valve reaches a gain value + 1%, and then executing the opening action according to a second gain value + 1% until the regulating valve is opened to the initial opening degree of 60%;
and thirdly, after the regulating valve is opened to 60 percent of opening degree, the regulating valve is quickly opened to 90 percent of full degree.
Embodiment 4
Embodiment 4 when the system is present, the PIC detects P2And when the pressure is more than or equal to 96bar, opening the valve according to the opening step of the regulating valve, and locking the high-pressure pump P1 to stop immediately to reduce the system operating pressure in time.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (9)

1. A high-pressure membrane filtration system comprises at least one membrane component, a high-pressure pump, a circulating pump, a raw water pipeline, a concentrated water pipeline and a PLC (programmable logic controller), and is characterized in that the high-pressure pump is arranged on the raw water pipeline and used for inputting filtered raw water to the membrane filtration system, a water inlet flow meter used for detecting water inlet flow is arranged at the inlet end of the high-pressure pump, a pressure transmitter S1 used for detecting the water inlet pressure of the membrane component is arranged at the inlet end of the membrane component, a pressure transmitter S2 used for detecting the concentrated water outlet pressure of the membrane component is arranged at the outlet end of the membrane component, the circulating pump is arranged on the concentrated water pipeline at the outlet of the membrane component and used for inputting the concentrated water generated by the membrane component to a next membrane component or a next procedure, a high-pressure regulating valve is arranged at the concentrated water outlet end of the membrane filtration system, a concentrated water flow meter used for detecting the water outlet flow of the concentrated water is arranged at the outlet end of the high-pressure regulating valve, and the high-pressure pump, The water inlet flow meter, the concentrated water flow meter, the pressure transmitter and the high-pressure regulating valve are all connected with the PLC, and the PLC controls the recovery rate of the system according to the recovery rate H of the system; performing chain protection on the system according to the transmembrane pressure difference K;
the transmembrane pressure difference K is max (P)2-P1) The system recovery rate H ═ F1-F2)/F1X is 100%; wherein the content of the first and second substances,
P1the water inlet pressure value of the membrane component detected by the pressure transmitter S1;
P2the membrane module effluent pressure value detected by the pressure transmitter S2;
F1the water inlet flow value of the high-pressure membrane filtration system is detected by a water inlet flowmeter;
F2the value of the concentrated water outlet flow of the high-pressure membrane filtration system is detected by the concentrated water flowmeter.
2. The method for controlling the recovery rate of a high-pressure membrane filtration system according to claim 1, wherein the valve is closed in the step of adjusting the valve to close when a negative deviation occurs in the recovery rate of the system and the negative deviation exceeds an allowable deviation range; when the system recovery rate has positive deviation and the positive deviation of the recovery rate exceeds the allowable deviation range, the valve is opened according to the opening step of the regulating valve until the system recovery rate is within the allowable deviation range, and the regulation is stopped.
3. The recovery rate control method of a high pressure membrane filtration system as claimed in claim 2, wherein the regulating valve closing step comprises:
firstly, rapidly closing an adjusting valve to an initial opening degree;
secondly, after the regulating valve is quickly closed to the initial opening, closing actions are alternately executed according to the gain value and the pulse time, namely, after the opening of the regulating valve reaches one gain value, the pulse time is executed once, and after the pulse time is finished, the closing actions are continuously executed according to a second gain value;
thirdly, repeating the second step until the recovery rate of the system is within the allowable deviation range, and stopping closing action;
the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to a reduced value of the valve opening; the pulse time refers to the stop time between the two closing actions of the high-pressure regulating valve which is executed in a segmented mode in the closing process.
4. The recovery rate control method of a high pressure membrane filtration system as recited in claim 3, wherein said gain value is a percentage value of valve opening reduction.
5. The recovery rate control method of a high pressure membrane filtration system according to claim 2, wherein the regulator valve opening step includes:
the method comprises the following steps that firstly, opening actions are alternately executed according to gain values and pulse time, namely, after the opening degree of an adjusting valve reaches one gain value, the pulse time is executed once, and after the pulse time is finished once, the opening actions are continuously executed according to a second gain value;
step two, repeating the step one until the regulating valve is opened to the initial opening degree;
thirdly, after the regulating valve is opened to the initial opening degree, the regulating valve is quickly opened until the regulating valve is fully opened;
the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to an increase value of the valve opening; the pulse time refers to the stop time between the two opening actions of the high-pressure regulating valve which is opened in a segmented manner.
6. The recovery rate control method of a high pressure membrane filtration system as recited in claim 5, wherein said gain value is a percentage value of an increase in valve opening.
7. A method of protecting a high pressure membrane filtration system according to claim 1, comprising: when any one of a high-pressure protection value, a flow protection value, a membrane flux protection value or a transmembrane pressure difference protection value of the system reaches a set value, opening a valve according to a starting step of a regulating valve, and reducing the operating pressure of the system in time;
the set value of the high-voltage protection value is as follows: p2Greater than or equal to the design pressure multiplied by 120 percent;
the set value of the flow protection value is as follows: f2Less than or equal to the design concentrated water flow value multiplied by 50 percent;
the set values of the membrane flux protection values are: (F)1-F2) More than or equal to (design inflow flow value-design concentrated water flow value) multiplied by 120 percent;
the set value of the transmembrane pressure difference protection value is as follows: k is larger than or equal to the maximum transmembrane pressure difference value which can be borne by a membrane module designed by the system.
8. The recovery rate control method of a high pressure membrane filtration system according to claim 7, wherein the regulator valve opening step comprises:
the first step is as follows: the second step is executed after the instrument signal continuously exceeds the set response time;
step two, alternately executing opening action according to the gain value and the pulse time, namely executing the pulse time once after the opening degree of the regulating valve reaches one gain value, and continuing executing the opening action according to the second gain value after the pulse time is finished;
thirdly, repeating the first step until the regulating valve is opened to the initial opening degree;
fourthly, after the regulating valve is opened to the initial opening degree, the regulating valve is quickly opened until the regulating valve is fully opened;
the response time refers to the time that the system instrument signal is stable continuously at a value; the initial opening refers to the valve opening of the high-pressure regulating valve when the system pressure is less than 4 bar; the gain value refers to an increase value of the valve opening; the pulse time refers to the stop time between the two opening actions of the high-pressure regulating valve which is opened in a segmented manner.
9. The recovery rate control method of a high pressure membrane filtration system as recited in claim 7, wherein the step of immediately stopping the high pressure pump is performed in parallel.
CN202110855522.XA 2021-07-28 2021-07-28 High-pressure membrane filtration system and recovery rate control and protection method Pending CN113499690A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114906902A (en) * 2022-05-17 2022-08-16 中联环股份有限公司 Distributed CMF membrane system process

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114906902A (en) * 2022-05-17 2022-08-16 中联环股份有限公司 Distributed CMF membrane system process

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