A membrane online chemical cleaning real-time monitoring system and method

Abstract

The invention discloses a membrane online chemical cleaning real-time monitoring system, the system comprises: a sampling module connected to the water outlet end of a measured membrane system, the sampling module comprising a sample container, the sample container being used to hold samples; a chemical cleaning module connected to the water inlet end of the measured membrane system, the chemical cleaning module being used to inject chemical cleaning agents into the measured membrane system; a monitoring module being used to monitor effective chlorine information or ORP information or pH information or TDS information of the sample; an analysis module connected to the monitoring module, the analysis module being used to calculate an actual membrane flux recovery rate of the measured membrane system according to the effective chlorine information or ORP information or pH information or TDS information, and compare the actual membrane flux recovery rate with the set membrane flux recovery rate; the system can monitor the cleaning effect of the membrane online chemical cleaning in real time and accurately.

Description

Technical Field

[0001] The present invention belongs to the technical field of membrane online chemical cleaning, and more specifically, relates to a membrane online chemical cleaning real-time monitoring system and method. Background Art

[0002] Ultrafiltration membrane technology has been widely used in sewage and recycled water treatment processes. However, during the operation of ultrafiltration membranes, membrane fouling has always been the biggest challenge faced by operators and researchers. During the operation of the membrane, a layer of sediment, namely the "mud cake" layer, will be produced on the surface of the membrane, which increases the resistance of the water production channel and causes a decrease in the water production flow rate. In addition, these sediments will aggravate the concentration polarization phenomenon. Under the action of the concentration gradient, the solute will diffuse from the membrane surface to the bulk solution, forming a boundary layer, which increases the fluid resistance and local osmotic pressure, thereby causing the water flux to further decrease.

[0003] Membrane cleaning is an important means to restore membrane performance. Cleaning methods include physical cleaning, chemical cleaning and a combination of the two. Physical cleaning usually involves air / water backwashing at regular intervals. When the membrane is severely contaminated, it is difficult to fully restore membrane performance by physical cleaning alone. Chemical cleaning must be used at this time. Chemical cleaning removes pollutants from the membrane surface by chemical reactions between chemical cleaning agents and pollutants. Studies have shown that alkaline cleaning is more effective in alleviating pollution caused by organic matter and microorganisms, while acid cleaning is more effective in alleviating pollution caused by inorganic metal elements (such as Al, Ca and Mg, etc.), which can dissolve metal ions on the membrane surface and adsorbed in the membrane pores.

[0004] At present, in the actual operation of membrane chemical cleaning, the chemical cleaning strategy is mainly carried out according to the manufacturer's instruction manual, and the evaluation of the cleaning effect is based on the flow change after the water production is restored. It is impossible to evaluate the chemical cleaning effect online in real time. If the cleaning is not sufficient, it is easy to cause the transmembrane pressure difference of the ultrafiltration membrane to rise rapidly in a short period of time, and the treated water volume to drop rapidly. It must be cleaned again because the residue on the surface of the membrane will cause crystallization and microbial reproduction. In addition, the higher the frequency of chemical cleaning, the greater the damage to the membrane elements, which will seriously affect the service life of the membrane system. At the same time, frequent chemical cleaning increases the use of chemical agents and increases the operating cost of the ultrafiltration membrane system. Summary of the invention

[0005] The purpose of the present invention is to provide a membrane online chemical cleaning real-time monitoring system and method in view of the deficiencies in the prior art. The monitoring module of the system can monitor the effective chlorine information or ORP information or pH information or TDS information of the sample, and the analysis module calculates the actual membrane flux recovery rate of the measured membrane system according to the effective chlorine information or ORP information or pH information or TDS information, and compares the actual membrane flux recovery rate with the set membrane flux recovery rate, so as to monitor the cleaning effect of the membrane online chemical cleaning in real time and accurately.

[0006] In order to achieve the above object, the present invention provides a membrane online chemical cleaning real-time monitoring system, the system comprising:

[0007] A sampling module is connected to the water outlet of the membrane system to be tested, and the sampling module includes a sample container, and the sample container is used to hold the sample;

[0008] A chemical cleaning module connected to the water inlet of the measured membrane system, and used for injecting a chemical cleaning agent into the measured membrane system;

[0009] A monitoring module, used for monitoring the effective chlorine information, ORP information, pH information or TDS information of the sample;

[0010] An analysis module is connected to the monitoring module, and is used to calculate the actual membrane flux recovery rate of the measured membrane system according to the effective chlorine information or the ORP information or the pH information or the TDS information, and compare the actual membrane flux recovery rate with the set membrane flux recovery rate.

[0011] Optionally, the sample holding container is connected to a sample injection pipeline, and a sample injection electric valve, a pressure reducing valve and a pressure gauge are sequentially arranged on the sample injection pipeline along the sample injection direction, a liquid level gauge is arranged in the sample holding container, the sample holding container is connected to a loop pipeline, and a pressure pump, a loop electric valve and a check valve are sequentially arranged on the loop pipeline along the sample reflux direction, the pressure pump is arranged in the sample holding container, and a drain valve is arranged at the bottom of the sample holding container.

[0012] Optionally, the chemical cleaning module includes an alkaline cleaning unit and an acid cleaning unit.

[0013] Optionally, the alkali washing unit comprises:

[0014] An alkali washing tank, wherein the alkali washing tank is connected to the water inlet end of the measured membrane system through a first pipeline, an alkali washing circulation pump and an alkali washing electric valve are arranged on the first pipeline, and an alkali washing drain valve is arranged at the bottom of the alkali washing tank;

[0015] The alkali washing solution storage tank is connected to the alkali washing solution tank through a second pipeline, and the second pipeline is provided with an alkali washing metering pump and an alkali-resistant electric valve.

[0016] Optionally, the pickling unit comprises:

[0017] A pickling solution tank, wherein the pickling solution tank is connected to the water inlet end of the measured membrane system through a third pipeline, a pickling circulation pump and a pickling electric valve are arranged on the third pipeline, and a pickling drain valve is arranged at the bottom of the pickling solution tank;

[0018] The pickling solution storage tank is connected to the pickling solution tank through a fourth pipeline, and the fourth pipeline is provided with a pickling metering pump and an acid-resistant electric valve.

[0019] Optionally, it also includes a fifth pipeline, one end of which is connected to the water outlet of the membrane system to be tested, and the other end of the fifth pipeline is connected to the water inlet of the membrane system to be tested after passing through the chemical cleaning module, and the injection pipeline and the loop pipeline are connected to the fifth pipeline at the upstream position of the chemical cleaning module.

[0020] Optionally, the monitoring module includes:

[0021] A monitoring probe, which is disposed in the sample container and is used to monitor the sample;

[0022] A display unit connected to the monitoring probe;

[0023] a cleaning liquid container, wherein the cleaning liquid can be contained in the cleaning liquid container;

[0024] A cleaning pump is arranged in the cleaning liquid container. The output end of the cleaning pump is connected to a cleaning nozzle through a cleaning pipe. The cleaning nozzle is arranged on one side of the monitoring probe.

[0025] Optionally, a control unit is further included, and the control unit is connected to the sampling module, the chemical cleaning module, the monitoring module and the analysis module.

[0026] The present invention also provides a membrane online chemical cleaning real-time monitoring method, using the membrane online chemical cleaning real-time monitoring system according to the above method, the method comprises:

[0027] Obtain samples from the outlet of the membrane system under test;

[0028] Detect the effective chlorine information, ORP information, pH information or TDS information of the sample;

[0029] Set the set membrane flux recovery rate of the measured membrane system;

[0030] The actual membrane flux recovery rate of the measured membrane system is calculated according to the effective chlorine information or the ORP information or the pH information or the TDS information, and the actual membrane flux recovery rate is compared with the set membrane flux recovery rate.

[0031] Optionally, it also includes:

[0032] When the actual membrane flux recovery rate is less than the set membrane flux recovery rate, increasing the injection amount of the chemical cleaning agent and / or increasing the chemical cleaning time;

[0033] When the actual membrane flux recovery rate is not less than the set membrane flux recovery rate, chemical cleaning is stopped and the chemical cleaning agent is discharged.

[0034] The present invention provides a membrane online chemical cleaning real-time monitoring system and method, which has the following beneficial effects:

[0035] 1. The monitoring module of the system can monitor the effective chlorine information, ORP information, pH information or TDS information of the sample. The analysis module calculates the actual membrane flux recovery rate of the measured membrane system according to the effective chlorine information, ORP information, pH information or TDS information, and compares the actual membrane flux recovery rate with the set membrane flux recovery rate, so as to monitor the cleaning effect of the membrane online chemical cleaning in real time and accurately;

[0036] 2. The method can also monitor the cleaning effect of online chemical cleaning of the membrane in real time and accurately. When the actual membrane flux recovery rate is less than the set membrane flux recovery rate, the injection amount of the chemical cleaning agent is increased and / or the chemical cleaning time is increased. When the actual membrane flux recovery rate is not less than the set membrane flux recovery rate, the chemical cleaning is stopped and the chemical cleaning agent is discharged. The online chemical cleaning of the membrane is controlled in real time to ensure the cleaning effect while saving cleaning costs.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0039] Figure 1 A schematic structural diagram of a membrane online chemical cleaning real-time monitoring system according to an embodiment of the present invention is shown.

[0040] Figure 2 A schematic structural diagram of a monitoring module of a membrane online chemical cleaning real-time monitoring system according to an embodiment of the present invention is shown.

[0041] Figure 3 A model diagram of actual membrane flux recovery rate and set membrane flux recovery rate during chemical cleaning according to an embodiment of the present invention is shown.

[0042] Figure 4 A graph showing the variation of transmembrane pressure difference over operating time of an ultrafiltration membrane system of a reclaimed water plant according to an embodiment of the present invention with and without the use of the present invention is shown.

[0043] Description of reference numerals:

[0044] 1. Sampling module; 2. Measured membrane system; 3. Sample container; 4. Chemical cleaning module; 5. Monitoring module; 6. Analysis module; 7. Sample injection pipeline; 8. Sample injection electric valve; 9. Pressure reducing valve; 10. Pressure gauge; 11. Liquid level gauge; 12. Loop pipeline; 13. Pressure pump; 14. Loop electric valve; 15. Check valve; 16. Drain valve; 17. Alkali washing solution tank; 18. First pipeline; 19. Alkali washing circulation pump; 20. Alkali washing electric valve; 21. Alkali washing drain valve; 22. Alkali washing solution storage tank; 2 3. Second pipeline; 24. Alkali washing metering pump; 25. Alkali-resistant electric valve; 26. Pickling solution tank; 27. Third pipeline; 28. Pickling circulation pump; 29. ​​Pickling electric valve; 30. Pickling drain valve; 31. Pickling solution storage tank; 32. Fourth pipeline; 33. Pickling metering pump; 34. Acid-resistant electric valve; 35. Fifth pipeline; 36. Branch pipeline; 37. Monitoring probe; 38. Display unit; 39. Cleaning liquid container; 40. Cleaning pump; 41. Cleaning nozzle; 42. Cleaning brush; 43. Control unit. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0046] like Figures 1 to 4 As shown, the present invention provides a membrane online chemical cleaning real-time monitoring system, the system comprising:

[0047] The sampling module 1 is connected to the water outlet of the membrane system 2 to be tested. The sampling module 1 includes a sample container 3, which is used to hold the sample;

[0048] A chemical cleaning module 4 is connected to the water inlet of the membrane system 2 to be tested, and the chemical cleaning module 4 is used to inject a chemical cleaning agent into the membrane system 2 to be tested;

[0049] Monitoring module 5, used for monitoring the available chlorine information, ORP information, pH information or TDS information of the sample;

[0050] The analysis module 6 is connected to the monitoring module 5, and is used to calculate the actual membrane flux recovery rate of the measured membrane system 2 according to the effective chlorine information or the ORP information or the pH information or the TDS information, and compare the actual membrane flux recovery rate with the set membrane flux recovery rate.

[0051] Specifically, during the chemical cleaning process, the chemical cleaning module 4 injects a chemical cleaning agent into the membrane system 2 to be tested, the sampling module 1 takes a water sample from the outlet of the membrane system 2 to be tested as a sample, and places the sample in a sample container 3, the monitoring module 5 performs real-time monitoring of the effective chlorine information or ORP (oxidation-reduction potential) information or pH (acidity) information or TDS (total dissolved solids) information on the sample in the sample container 3, and the analysis module 6 calculates the actual membrane flux recovery rate of the membrane system 2 to be tested based on the effective chlorine information or ORP information or pH information or TDS information, and compares the actual membrane flux recovery rate with the set membrane flux recovery rate, so as to achieve real-time and accurate monitoring of the chemical cleaning effect; the set membrane flux recovery rate can be set by a technician in this field according to the membrane water production flow prediction model of the membrane system 2 to be tested. For different chemical cleaning requirements of the membrane system 2 to be tested, the set membrane flux recovery rate set for different membrane systems 2 to be tested is different.

[0052] Optionally, the sample container 3 is connected to a sample injection pipeline 7, on which a sample injection electric valve 8, a pressure reducing valve 9 and a pressure gauge 10 are sequentially arranged along the sample injection direction; a liquid level gauge 11 is arranged in the sample container 3; the sample container 3 is connected to a loop pipeline 12, on which a pressure pump 13, a loop electric valve 14 and a check valve 15 are sequentially arranged along the sample reflux direction; the pressure pump 13 is arranged in the sample container 3, and a drain valve 16 is arranged at the bottom of the sample container 3.

[0053] Specifically, one end of the sampling pipeline 7 is connected to the water outlet end of the membrane system 2 to be tested, and the other end of the sampling pipeline 7 is connected to the sample container 3. One end of the loop pipeline 12 is connected to the pressure pump 13 in the sample container 3, and the other end of the loop pipeline 12 is connected to the chemical cleaning module 4 for the reflux of the sample with the cleaning liquid; the liquid level meter 11 is used to monitor the liquid level of the sample in the sample container 3, so as to realize the automatic control of the start and stop of sampling and sampling.

[0054] Optionally, the chemical cleaning module 4 includes an alkaline cleaning unit and an acid cleaning unit.

[0055] Specifically, according to different components to be cleaned, an alkali cleaning unit and an acid cleaning unit may be selected to provide chemical cleaning agents for chemical cleaning.

[0056] Optionally, the alkali washing unit comprises:

[0057] Alkali washing dissolving tank 17, the alkaline washing dissolving tank 17 is connected to the water inlet end of the measured membrane system 2 through a first pipeline 18, an alkaline washing circulation pump 19 and an alkaline washing electric valve 20 are arranged on the first pipeline 18, and an alkaline washing emptying valve 21 is arranged at the bottom of the alkaline washing dissolving tank 17;

[0058] The alkali washing solution storage tank 22 is connected to the alkali washing solution tank 17 through a second pipeline 23 , and an alkali washing metering pump 24 and an alkali-resistant electric valve 25 are provided on the second pipeline 23 .

[0059] Specifically, the alkaline washing solution storage tank 22 is used to store the alkaline washing solution, which can be injected into the alkaline washing solvent tank 17 through the second pipeline 23 and the alkaline washing metering pump 24, and diluted and mixed with tap water or membrane produced water in the alkaline washing solvent tank 17. The mixed alkaline washing solution is injected into the water inlet end of the membrane system 2 to be tested through the first pipeline 18 and the alkaline washing circulation pump 19 to perform alkaline chemical cleaning on the membrane system 2 to be tested.

[0060] Optionally, the alkaline cleaning solution may use sodium hypochlorite and / or sodium hydroxide.

[0061] Optionally, the pickling unit comprises:

[0062] A pickling solution tank 26, the pickling solution tank 26 is connected to the water inlet end of the measured membrane system 2 through a third pipeline 27, a pickling circulation pump 28 and a pickling electric valve 29 are arranged on the third pipeline 27, and a pickling drain valve 30 is arranged at the bottom of the pickling solution tank 26;

[0063] The pickling solution storage tank 31 is connected to the pickling solution tank 26 via a fourth pipeline 32 , and a pickling metering pump 33 and an acid-resistant electric valve 34 are provided on the fourth pipeline 32 .

[0064] Specifically, the pickling solution storage tank 31 is used to store the pickling solution, and the pickling solution can be injected into the pickling solvent tank 26 through the fourth pipeline 32 and the pickling metering pump 33, and diluted and mixed with tap water or membrane produced water in the pickling solvent tank 26. The mixed pickling solution is injected into the water inlet end of the membrane system 2 to be tested through the third pipeline 27 and the pickling circulation pump 28, and the membrane system 2 to be tested is subjected to acidic chemical cleaning.

[0065] Optionally, the pickling solution may use citric acid, oxalic acid or hydrochloric acid.

[0066] Optionally, it also includes a fifth pipeline 35, one end of the fifth pipeline 35 is connected to the water outlet end of the membrane system 2 to be tested, and the other end of the fifth pipeline 35 is connected to the water inlet end of the membrane system 2 to be tested after passing through the chemical cleaning module 4, and the sampling pipeline 7 and the loop pipeline 12 are connected to the upstream position of the chemical cleaning module 4 on the fifth pipeline 35.

[0067] Specifically, the fifth pipeline 35 serves as the main pipeline of the chemical cleaning solution, one end of the fifth pipeline 35 is connected to the water outlet end of the membrane system 2 to be tested, one end of the sampling pipeline 7 is connected to the fifth pipeline 35, the other end of the loop pipeline 12 is also connected to the fifth pipeline 35, and the middle part of the fifth pipeline 35 is respectively connected to the alkaline washing solvent tank 17 and the acid washing solvent tank 26 through a branch pipeline 36, providing liquid to the alkaline washing solvent tank 17 and the acid washing solvent tank 26 so as to mix with the alkaline washing solution and the acid washing solution.

[0068] Optionally, the monitoring module 5 includes:

[0069] A monitoring probe 37, which is disposed in the sample container 3 and is used to monitor various parameter information of the sample;

[0070] A display unit 38 connected to the monitoring probe 37;

[0071] a cleaning liquid container 39, wherein the cleaning liquid container 39 can contain cleaning liquid;

[0072] The cleaning pump 40 is disposed in the cleaning liquid container 39 . The output end of the cleaning pump 40 is connected to a cleaning nozzle 41 through a cleaning pipe. The cleaning nozzle 41 is disposed on one side of the monitoring probe 37 .

[0073] Specifically, the monitoring probe 37 adopts a detachable structure, which can monitor the effective chlorine information, ORP information, pH information or TDS information of the sample; the display unit 38 is used to display the monitoring results of the monitoring probe 37, and the cleaning pump 40 can extract the cleaning liquid in the cleaning liquid container 39, and flush the monitoring probe 37 through the cleaning nozzle 41 to ensure the cleanliness of the monitoring probe 37 to improve the monitoring accuracy.

[0074] In one example, a plurality of monitoring probes 37 are provided, each monitoring probe 37 respectively monitors the effective chlorine information, ORP information, PH information, and TDS information of the sample. The plurality of monitoring probes 37 are arranged circumferentially, and a cleaning brush 42 is rotatably provided at the center of the plurality of monitoring probes 37. When the cleaning nozzle 41 sprays liquid to clean the monitoring probe 37, the liquid impacts one side of the cleaning brush 42, so that the cleaning brush 42 rotates, and the bristles of the cleaning brush 42 are used to clean the monitoring probe 37.

[0075] Optionally, a control unit 43 is further included, and the control unit 43 is connected to the sampling module 1 , the chemical cleaning module 4 , the monitoring module 5 and the analysis module 6 .

[0076] Specifically, the control unit 43 may be a PLC, and the control unit 43 can realize automatic control of various electronic control components in the sampling module 1 , the chemical cleaning module 4 , and the monitoring module 5 .

[0077] The present invention also provides a membrane online chemical cleaning real-time monitoring method, using the membrane online chemical cleaning real-time monitoring system according to the above method, the method comprises:

[0078] Obtaining a sample from the water outlet of the membrane system 2 under test;

[0079] Detect the effective chlorine information, ORP information, pH information or TDS information of the sample;

[0080] Setting a set membrane flux recovery rate of the measured membrane system 2;

[0081] The actual membrane flux recovery rate of the measured membrane system 2 is calculated according to the effective chlorine information or the ORP information or the pH information or the TDS information, and the actual membrane flux recovery rate is compared with the set membrane flux recovery rate.

[0082] Specifically, when alkaline chemical cleaning is performed on the membrane system 2 to be tested, the monitoring module 5 monitors the effective chlorine information, ORP information or pH information of the sample through the monitoring probe 37 .

[0083] Optionally, the “effective chlorine decay rate-actual membrane flux recovery rate” model is: f 1 =a 1 ·Δ Cl +b 1 ;

[0084] Among them, f 1 is the membrane flux change rate; Δ Cl is the effective chlorine attenuation rate of the cleaning solution during the alkaline cleaning process; a 1 、b 1 is the fitting parameter.

[0085] Optionally, the “ORP change rate-actual membrane flux recovery rate” model is: f 2 =a 2 ·Δ ORP +b 2 ;

[0086] Among them, f 2 is the membrane flux recovery rate; Δ ORP is the ORP change rate of the cleaning solution during the alkaline cleaning process; a 2 、b 2 is the fitting parameter.

[0087] Optionally, the “alkaline washing pH change rate-actual membrane flux recovery rate” model is: f 3 =a 3 ·Δ pH1 +b 3 ;

[0088] Among them, f 3 is the membrane flux recovery rate; Δ pH1is the pH change rate of the cleaning solution during alkaline cleaning; a 3 、b 3 is the fitting parameter.

[0089] When the membrane system 2 to be tested is subjected to acid chemical cleaning, the monitoring module 5 monitors the TDS information or pH information of the sample through the monitoring probe 37 .

[0090] Optionally, the “TDS change rate-actual membrane flux recovery rate” model is: f 4 =a 4 Δ TDS +b 4 ;

[0091] Among them, f 4 is the membrane flux recovery rate; Δ TDS is the TDS change rate of the cleaning liquid during the pickling process; a 4 、b 4 is the fitting parameter.

[0092] Optionally, the “acid wash pH change rate-actual membrane flux recovery rate” model is: f 5 =a 5 Δ pH2 +b 5 ;

[0093] Among them, f 5 is the membrane flux recovery rate; Δ pH2 is the pH change rate of the cleaning solution during the pickling process; a 5 、b 5 is the fitting parameter.

[0094] Optionally, it also includes:

[0095] When the actual membrane flux recovery rate is less than the set membrane flux recovery rate, increase the injection amount of the chemical cleaning agent and / or increase the chemical cleaning time;

[0096] When the actual membrane flux recovery rate is not less than the set membrane flux recovery rate, the chemical cleaning is stopped and the chemical cleaning agent is discharged.

[0097] Specifically, it also includes automatic control of chemical cleaning according to the above-mentioned comparison results, and automatically adjusts the chemical cleaning liquid concentration and chemical cleaning time according to the comparison results; if the calculated actual membrane flux recovery rate is less than the set membrane flux recovery rate, the control unit 43 automatically adjusts the chemical cleaning operation strategy, starts the alkali washing metering pump 24 / acid washing metering pump 33 to replenish the alkali washing agent / acid washing agent, and / or extends the working time of the alkali washing circulation pump 19 / acid washing circulation pump 28; if the calculated actual membrane flux recovery rate is not less than the set membrane flux recovery rate, the chemical cleaning is stopped and the cleaning liquid is discharged to save cleaning costs.

[0098] In summary, when the membrane online chemical cleaning real-time monitoring method provided by the present invention is implemented, the membrane online chemical cleaning real-time monitoring system is used, taking the application in the ultrafiltration membrane system of a reclaimed water plant as an example: Figure 4 As shown, the transmembrane pressure difference increased significantly at 0h and 60h without using the present invention for chemical cleaning, and the transmembrane pressure difference increased to 44.0kPa and 43.6kPa respectively at 60h and 130h; after running for 130h, the present invention was used for chemical cleaning, and the trend of the subsequent increase in the transmembrane pressure difference slowed down significantly. At 200h and 278h, the transmembrane pressure difference was 37.7kPa and 35.6kPa respectively. The results show that after using the present invention, the transmembrane pressure difference can be reduced by 18% within the same operating time after chemical cleaning. Combined with the above analysis, the membrane online chemical cleaning real-time monitoring system and method provided by the present invention can effectively improve the membrane chemical cleaning effect, alleviate membrane fouling, reduce the frequency of chemical cleaning, extend the membrane life and reduce the operating cost.

[0099] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A membrane online chemical cleaning real-time monitoring system, characterized in that: The system includes: A sampling module is connected to the water outlet of the membrane system to be tested, and the sampling module includes a sample container, and the sample container is used to hold the sample; A chemical cleaning module connected to the water inlet of the measured membrane system, and used for injecting a chemical cleaning agent into the measured membrane system; A monitoring module, used for monitoring the effective chlorine information, ORP information, pH information or TDS information of the sample; An analysis module connected to the monitoring module, the analysis module is used to calculate the actual membrane flux recovery rate of the measured membrane system according to the effective chlorine information or the ORP information or the pH information or the TDS information, and compare the actual membrane flux recovery rate with the set membrane flux recovery rate; When alkaline chemical cleaning is performed on the membrane system under test, the monitoring module monitors the effective chlorine information, ORP information or pH information of the sample through the monitoring probe; Among them, the "effective chlorine decay rate-actual membrane flux recovery rate" model is: f1=a1·Δ Cl +b1; Where f1 is the membrane flux change rate; Δ Cl is the effective chlorine decay rate of the cleaning solution during alkaline washing; a1 and b1 are fitting parameters; Among them, the "ORP change rate-actual membrane flux recovery rate" model is: f2=a2·Δ ORP +b2; Where, f2 is the membrane flux recovery rate; Δ ORP is the ORP change rate of the cleaning solution during alkaline cleaning; a2 and b2 are fitting parameters; Among them, the "alkaline washing pH change rate-actual membrane flux recovery rate" model is: f3=a3·Δ pH1 +b3; Where, f3 is the membrane flux recovery rate; Δ pH1 is the pH change rate of the cleaning solution during alkaline cleaning; a3 and b3 are fitting parameters; When the membrane system under test is subjected to acid chemical cleaning, the monitoring module monitors the TDS information or pH information of the sample through the monitoring probe; Among them, the "TDS change rate-actual membrane flux recovery rate" model is: f4=a4·ΔTDS+b4; Among them, f4 is the membrane flux recovery rate; ΔTDS is the TDS change rate of the cleaning solution during the pickling process; a4 and b4 are fitting parameters; Among them, the "acid washing pH change rate-actual membrane flux recovery rate" model is: f5=a5·Δ pH2 +b5; Where, f5 is the membrane flux recovery rate; Δ pH2 is the pH change rate of the cleaning solution during the pickling process; a5 and b5 are fitting parameters.

2. The membrane online chemical cleaning real-time monitoring system according to claim 1 is characterized in that: The sample holding container is connected to a sample injection pipeline, and a sample injection electric valve, a pressure reducing valve and a pressure gauge are sequentially arranged on the sample injection pipeline along the sample injection direction; a liquid level gauge is arranged in the sample holding container; the sample holding container is connected to a loop pipeline, and a pressure pump, a loop electric valve and a check valve are sequentially arranged on the loop pipeline along the sample reflux direction; the pressure pump is arranged in the sample holding container, and a drain valve is arranged at the bottom of the sample holding container.

3. The membrane online chemical cleaning real-time monitoring system according to claim 1 is characterized in that: The chemical cleaning module includes an alkaline cleaning unit and an acid cleaning unit.

4. The membrane online chemical cleaning real-time monitoring system according to claim 3 is characterized in that: The alkali washing unit comprises: An alkali washing tank, wherein the alkali washing tank is connected to the water inlet end of the measured membrane system through a first pipeline, an alkali washing circulation pump and an alkali washing electric valve are arranged on the first pipeline, and an alkali washing drain valve is arranged at the bottom of the alkali washing tank; The alkali washing solution storage tank is connected to the alkali washing solution tank through a second pipeline, and the second pipeline is provided with an alkali washing metering pump and an alkali-resistant electric valve.

5. The membrane online chemical cleaning real-time monitoring system according to claim 4 is characterized in that: The pickling unit comprises: A pickling solution tank, wherein the pickling solution tank is connected to the water inlet end of the measured membrane system through a third pipeline, a pickling circulation pump and a pickling electric valve are arranged on the third pipeline, and a pickling drain valve is arranged at the bottom of the pickling solution tank; The pickling solution storage tank is connected to the pickling solution tank through a fourth pipeline, and the fourth pipeline is provided with a pickling metering pump and an acid-resistant electric valve.

6. The membrane online chemical cleaning real-time monitoring system according to claim 2 is characterized in that: It also includes a fifth pipeline, one end of which is connected to the water outlet of the membrane system to be tested, and the other end of the fifth pipeline is connected to the water inlet of the membrane system to be tested after passing through the chemical cleaning module, and the sampling pipeline and the loop pipeline are connected to the upstream position of the chemical cleaning module on the fifth pipeline.

7. The membrane online chemical cleaning real-time monitoring system according to claim 1 is characterized in that: The monitoring module comprises: A monitoring probe, which is disposed in the sample container and is used to monitor the sample; A display unit connected to the monitoring probe; a cleaning liquid container, wherein the cleaning liquid container can contain cleaning liquid; A cleaning pump is arranged in the cleaning liquid container. The output end of the cleaning pump is connected to a cleaning nozzle through a cleaning pipe. The cleaning nozzle is arranged on one side of the monitoring probe.

8. The membrane online chemical cleaning real-time monitoring system according to claim 1 is characterized in that: It also includes a control unit, which is connected to the sampling module, the chemical cleaning module, the monitoring module and the analysis module.

9. A membrane online chemical cleaning real-time monitoring method, using the membrane online chemical cleaning real-time monitoring system according to claims 1-8, characterized in that: The method includes: Obtain samples from the outlet of the membrane system under test; Detect the effective chlorine information, ORP information, pH information or TDS information of the sample; Set the set membrane flux recovery rate of the measured membrane system; The actual membrane flux recovery rate of the measured membrane system is calculated according to the effective chlorine information or the ORP information or the pH information or the TDS information, and the actual membrane flux recovery rate is compared with the set membrane flux recovery rate.

10. The membrane online chemical cleaning real-time monitoring method according to claim 9, characterized in that: Also includes: When the actual membrane flux recovery rate is less than the set membrane flux recovery rate, increasing the injection amount of the chemical cleaning agent and / or increasing the chemical cleaning time; When the actual membrane flux recovery rate is not less than the set membrane flux recovery rate, chemical cleaning is stopped and the chemical cleaning agent is discharged.

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