Method for calculating working current of continuous electric desalting membrane block transformation test

Abstract

The application provides a continuous electric desalination membrane block transformation test working current calculation method. Through the introduction of the number of fresh water chambers and the polarization current density as core parameters and the adoption of a double formula comparison value strategy, the application realizes scientific setting and dynamic optimization of the working current in the EDI membrane block transformation test stage, effectively balances the ion exchange resin activation efficiency and the equipment corrosion protection demand, and significantly improves the production efficiency and product qualification rate of the transformation test.

Description

Technical Field

[0001] This invention relates to the field of current control for transition testing of continuous electrostatic desalination membrane blocks, and more particularly to a method for calculating the working current for transition testing of continuous electrostatic desalination membrane blocks. Background Technology

[0002] Continuous electrostatic precipitator (EDI) membrane modules, as core equipment in industrial pure water treatment, are widely used in industries such as power, electronics, pharmaceuticals, and chemicals. Their performance directly affects the stability of the produced water quality and the system's operating efficiency. In related technologies, a desalination system for EDI membrane modules is constructed through the synergistic operation of a DC electric field, ion exchange resin adsorption, and water dissociation. Specifically, this system covers the entire process from ion migration and resin regeneration to water quality control, including key structures such as desalination chambers, concentrate chambers, and electrode chambers. The filling and transformation testing of the ion exchange resin are crucial factors determining the membrane module's performance. With the development of water treatment technology, EDI membrane modules are gradually evolving towards higher efficiency and lower energy consumption. Current control during the transformation testing phase has become a significant factor affecting production efficiency and equipment lifespan.

[0003] However, existing methods for setting the conversion test current for EDI membrane modules typically rely on empirical or fixed-value control, lacking a scientific calculation model based on electrochemical principles and equipment protection requirements. This can lead to either insufficient current, resulting in prolonged testing time and increased water consumption, or excessive current, causing excessive formation of corrosive substances on the anode, accelerating the corrosion of precious metal coatings and ion exchange membranes, and reducing equipment lifespan. Furthermore, abnormal pH in the concentrate chamber and elevated temperature in the anode chamber can disrupt ion migration balance, affecting conversion efficiency. Therefore, ensuring sufficient activation of the ion exchange resin while preventing equipment corrosion and improving testing efficiency has become a key technical challenge restricting the industrial production of EDI membrane modules. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, the first objective of this invention is to provide a method for calculating the operating current of a continuous electro-desalination membrane block transition test.

[0006] The second objective of this invention is to provide a calculation device for the working current of a continuous electro-desalination membrane block transition test.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for calculating the operating current of a continuous electro-desalination membrane block transition test, comprising:

[0008] S1, obtain the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and calculate the first working current I1 based on the number of freshwater chambers and the electrodialysis potential difference;

[0009] S2, obtain the ion exchange resin ratio K1 in the concentrate chamber and the ion exchange resin ratio K2 in the desalination chamber, and calculate the polarization current I2 based on K1 and K2;

[0010] S3. Compare the first operating current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test operating current; otherwise, I1 is used as the actual transition test operating current.

[0011] S4. Adjust the power supply output current according to the actual transition test working current, and monitor the pH value at the concentrate chamber outlet and the temperature at the anode chamber outlet in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

[0012] In one embodiment of the present invention, the first operating current is calculated. :

[0013]

[0014] in, The operating current for the transition test of the continuous electrostatic desalination membrane module; For safety reasons, for The ratio of anion and cation exchange resins in the concentrate chamber of the membrane module. for The ratio of anion and cation exchange resins in the desalination chamber of the membrane module. For the potential difference required for membrane electrodialysis, a value of 100-120 is used for a 5-ton capacity membrane module, and 60-80 is used for a 3-ton capacity membrane module. for The number of freshwater chambers in the membrane module. It is Faraday's constant. To produce water for the freshwater chamber value, Water dissociation coefficient , For safety reasons, .

[0015] In one embodiment of the present invention, the polarization current I2 is calculated:

[0016]

[0017] in, The polarization current for the transition test of the continuous electro-deionization membrane block is A, where A is the membrane area of ​​a single chamber of the continuous electro-deionization membrane block. Polarization current density of continuous electro-desalination membrane block Generally take , The effective current coefficient for the transition test of continuous electro-desalination membrane blocks is generally [value missing]. .

[0018] In one embodiment of the present invention, the step of comparing the first operating current I1 with the polarization current I2, and if I1 is greater than I2, then using I2 as the actual transition test operating current; otherwise, using I1 as the actual transition test operating current, further includes:

[0019] S31, when I1>I2, I2 is taken as the actual working current, and this current value is recorded as the upper limit of the current for the membrane module transformation test;

[0020] S32, when I1≤I2, I1 is taken as the actual working current, and the current value is recorded as the current reference for the membrane module transformation test.

[0021] In one embodiment of the present invention, it further includes:

[0022] S5, monitor the resistivity of the freshwater outlet in the freshwater chamber. When the resistivity is greater than or equal to 16... At that time, the produced water is deemed qualified, and the EDI membrane module is judged to have passed the conversion test in combination with whether the test voltage is less than or equal to 150V.

[0023] To achieve the above objectives, a second aspect of the present invention provides a calculation device for the operating current of a continuous electro-desalination membrane block transition test, comprising:

[0024] The current parameter acquisition module is used to acquire the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and to calculate the first working current I1 based on the number of freshwater chambers and the electrodialysis potential difference.

[0025] The polarization current calculation module is used to obtain the ratio of ion exchange resin in the concentrate chamber K1 and the ratio of ion exchange resin in the desalination chamber K2, and to calculate the polarization current I2 based on K1 and K2.

[0026] The current selection and judgment module is used to compare the first operating current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test operating current; otherwise, I1 is used as the actual transition test operating current.

[0027] The current control and monitoring module is used to adjust the power supply output current according to the actual transition test working current, and to monitor the pH value at the concentrate chamber outlet and the anode chamber outlet temperature in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

[0028] The method and apparatus of this invention, by introducing a dual-parameter calculation model of the number of freshwater chambers and polarization current density, and by adopting the principle of taking the smaller value to determine the optimal operating current, effectively solves the problems of low production efficiency and equipment corrosion caused by unreasonable current control during the EDI membrane block transition test, and improves the efficiency of transition test and product qualification rate.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0031] Figure 1 A flowchart illustrating a method for calculating the working current of a continuous electro-desalination membrane block transition test, provided in an embodiment of this application;

[0032] Figure 2 A schematic diagram illustrating a method for calculating the working current of a continuous electro-desalination membrane block transition test, provided in an embodiment of this application.

[0033] Figure 3 This is a structural diagram of a device for calculating the working current of a continuous electro-desalination membrane block transition test, provided in an embodiment of this application.

[0034] The labels are as follows: 1-EDI membrane block test power supply, 2-EDI membrane block to be tested, 3-EDI membrane block electrode water chamber, 4-EDI membrane block concentrate chamber, 5-EDI membrane block desalination chamber, 6-EDI membrane block permeate resistivity meter, 7-EDI membrane block concentrate pH meter. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] The following describes, with reference to the accompanying drawings, a method and apparatus for calculating the working current of a continuous electro-desalination membrane block transition test according to an embodiment of the present invention.

[0038] Figure 1 This is a flowchart illustrating a method for calculating the operating current during the transition test of a continuous electro-desalination membrane block according to an embodiment of the present invention. Figure 1 As shown, it includes:

[0039] S1, obtain the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and calculate the first working current I1 based on the number of freshwater chambers and the electrodialysis potential difference;

[0040] S2, obtain the ion exchange resin ratio K1 in the concentrate chamber and the ion exchange resin ratio K2 in the desalination chamber, and calculate the polarization current I2 based on K1 and K2;

[0041] S3. Compare the first operating current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test operating current; otherwise, I1 is used as the actual transition test operating current.

[0042] S4. Adjust the power supply output current according to the actual transition test working current, and monitor the pH value at the concentrate chamber outlet and the temperature at the anode chamber outlet in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

[0043] Also includes:

[0044] S5, monitor the resistivity of the freshwater outlet in the freshwater chamber. When the resistivity is greater than or equal to 16... At that time, the produced water is deemed qualified, and the EDI membrane module is judged to have passed the conversion test in combination with whether the test voltage is less than or equal to 150V.

[0045] Specifically, this invention uses a preset calculation formula (1) and formula (2) to compare the calculation results of the two formulas. When the calculation result of formula (1) is greater than that of formula (2), the calculation result of formula (2) is adopted. This is because in the transformation test project, in order to promote water dissociation, the polarization current is the current to meet the water dissociation. Excessive water dissociation not only wastes power, but also causes the generation of corrosive substances after electrolysis, causing irreversible damage to the EDI membrane.

[0046] Furthermore, the number of freshwater chambers introduced into the continuous electro-deionization membrane module is used as a basic parameter for calculating the working current of the transition test. Different numbers of freshwater chambers correspond to different outputs of the EDI membrane module.

[0047] Furthermore, the maximum polarization current density is introduced as a verification parameter for the transition test operating current of the continuous electro-desalination membrane block, and the calculation of the transition test operating current is compared and verified.

[0048] Further, compare the calculated current of the transformation test working current. When formula (1) is not greater than formula (2), use the calculated current of formula (1); if it is greater, use the calculated current of formula (2).

[0049] Further, a pH meter is set at the outlet of the concentrated water chamber to detect the change in the pH of the concentrated water.

[0050] Further, a thermometer is designed at the outlet of the anode chamber to monitor the temperature change of the anode chamber. When the temperature exceeds 35°C, an alarm is given and the current is automatically cut off.

[0051] Further, a resistivity meter is set at the water production outlet of the fresh water chamber. When the resistivity of the produced water during the transformation test is greater than 16 , it is regarded that the produced water is qualified, and then, according to parameters such as the transformation voltage, comprehensively judge whether the EDI module becomes a qualified product. Generally speaking, the voltage after the transformation test is about 60 - 120V, and the maximum does not exceed 150V.

[0052] As Figure 2 shown, for a method for controlling the test current of a continuous electrodialysis module according to an embodiment of the present invention, first determine the equipment body parameters of the EDI module 2 to be tested, the number C value of the fresh water chambers, the output of the EDI module (such as 5-ton / 3-ton / 6-ton modules), and select the corresponding electrodialysis potential difference, the proportion K1 of the ion exchange resin in the concentrated water chamber, the proportion K2 of the ion exchange resin in the fresh water chamber, and the pH control value of the produced water in the fresh water chamber.

[0053] First, calculate the transformation test working current according to formula (1).

[0054] (1) Calculate according to the number of fresh water chambers of the continuous electrodialysis module:

[0055] (1)

[0056] Wherein, is the transformation test working current of the continuous electrodialysis module; is the safety factor, is ]>[[]]END]]the proportion of cation and anion exchange resins in the concentrated water chamber of the module, is the proportion of cation and anion exchange resins in the fresh water chamber of the module, is the potential difference required for electrodialysis of the module. For a 5-ton output module, take 100 - 120, and for a 3-ton output module, take 60 - 80, is the number of fresh water chambers of the module, is the Faraday constant, is the produced water in the fresh water chamber value, is the hydrolysis dissociation coefficient , For safety reasons, .

[0057] (2) The polarization current is calculated based on the polarization current density of the continuous electro-desalination membrane block:

[0058] (2)

[0059] in, The polarization current for the transition test of the continuous electro-deionization membrane module is given by A, where A is the area of ​​a single-chamber membrane in the continuous electro-deionization membrane module. ; Polarization current density of continuous electro-desalination membrane block Generally take , The effective current coefficient for the transition test of continuous electro-desalination membrane blocks is generally [value missing]. .

[0060] The final step in the production of continuous electrostatic desalination (ESP) membrane modules is the conversion test. This involves converting the internally packed salt-type ion exchange resins, transforming the sodium-type cation exchange resin into a hydrogen-type cation exchange resin and the chloride-type anion exchange resin into a hydroxide-type anion exchange resin. This ensures the quality of the effluent from the ESP membrane module. One testing standard is the product water resistivity, which is generally required to be no less than 16 ppm. Additionally, the voltage after the transition test should not exceed 150V.

[0061] Based on the calculation results, If a comparison is made, Less than Then For the actual transformation test operating current, if Smaller than The actual transformation test current is .

[0062] Preferably, the EDI membrane block with a test output of 5 tons has 45 freshwater chambers, and the corresponding electrodialysis potential difference is 120. (Full load operation), with the ion exchange resin ratio in the concentrate chamber being 1:1, then select... If the ratio of ion exchange resin in the freshwater chamber is 1:1, then select... According to formula (1), the current I is calculated as 1.56 + 1.4 = 2.96 A. According to formula (2), the calculated value is 3.13 A. After comparison, 2.96 A is selected as the test current value for the EDI membrane module transformation. Power supply 1 is adjusted, water is introduced, the power supply is turned on, and the output current of power supply 1 is adjusted to 2.96 A. The value of the resistivity meter of the produced water reaches 16. This indicates that the EDI membrane module has passed the transformation and the transformation test is complete.

[0063] This invention provides a formula for calculating the transition test current of continuous electro-desalination membrane blocks, effectively resolving the specific value of the transition test current. It offers a theoretical calculation formula for the transition test current in the production of continuous electro-desalination membrane blocks, which can be used as a reference in the production process. This eliminates the need for current control during the final stage of membrane block production—the transition test. This invention improves the calculation method for the transition test current of continuous electro-desalination membrane blocks and protects the transition test process (by designing other parameters), thereby increasing the production efficiency of the transition test stage in continuous electro-desalination and yielding significant economic benefits.

[0064] In summary, this invention uses the number of freshwater chambers and the water dissociation coefficient of the EDI membrane module as the basic parameters for calculating the transition test current. The transition test operating current is calculated, and then the polarization current is calculated using the polarization current density. The two are compared; if the former's calculated current is greater than the latter's, the latter transition test current is selected; if the former's calculated current is less than the latter's, the former transition test current is selected. Simultaneously, the pH of the concentrate chamber is monitored in real time during the transition test to prevent excessive transition test current. Under the transition test current operating condition, the permeate resistivity of the EDI membrane module is greater than 16. If the above conditions are met and the test voltage is not greater than 150V, it indicates that the EDI membrane block has passed the conversion test and the EDI membrane block product can be shipped.

[0065] To achieve the above embodiments, such as Figure 3 As shown, this embodiment also provides a calculation device 10 for the working current of the continuous electro-desalination membrane block transition test, including:

[0066] The current parameter acquisition module 100 is used to acquire the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and to calculate the first working current I1 based on the number of freshwater chambers and the electrodialysis potential difference.

[0067] The polarization current calculation module 200 is used to obtain the ratio of ion exchange resin in the concentrate chamber K1 and the ratio of ion exchange resin in the desalination chamber K2, and calculate the polarization current I2 based on K1 and K2.

[0068] The current selection and judgment module 300 is used to compare the first working current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test working current; otherwise, I1 is used as the actual transition test working current.

[0069] The current control and monitoring module 400 is used to adjust the power supply output current according to the actual transition test working current, and to monitor the pH value at the concentrate chamber outlet and the anode chamber outlet temperature in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

[0070] Further, calculate the first operating current. :

[0071]

[0072] in, The operating current for the transition test of the continuous electrostatic desalination membrane module; For safety reasons, for The ratio of anion and cation exchange resins in the concentrate chamber of the membrane module. for The ratio of anion and cation exchange resins in the desalination chamber of the membrane module. For the potential difference required for membrane electrodialysis, a value of 100-120 is used for a 5-ton capacity membrane module, and 60-80 is used for a 3-ton capacity membrane module. for The number of freshwater chambers in the membrane module. It is Faraday's constant. To produce water for the freshwater chamber value, Water dissociation coefficient , For safety reasons, .

[0073] Further, the polarization current I2 is calculated:

[0074]

[0075] in, The polarization current for the transition test of the continuous electro-deionization membrane block is A, where A is the membrane area of ​​a single chamber of the continuous electro-deionization membrane block. Polarization current density of continuous electro-desalination membrane block Generally take , The effective current coefficient for the transition test of continuous electro-desalination membrane blocks is generally [value missing]. .

[0076] Furthermore, the current selection and judgment module is also used for:

[0077] When I1>I2, I2 is taken as the actual operating current, and this current value is recorded as the upper limit of the current for the membrane module transition test.

[0078] When I1≤I2, I1 is taken as the actual operating current, and this current value is recorded as the current reference for the membrane module transformation test.

[0079] Furthermore, it also includes:

[0080] The product water monitoring module is used to monitor the resistivity of the freshwater outlet in the freshwater chamber. When the resistivity is greater than or equal to 16... At that time, the produced water is deemed qualified, and the EDI membrane module is judged to have passed the conversion test in combination with whether the test voltage is less than or equal to 150V.

[0081] The calculation device for the working current of the continuous electro-deionization membrane block transition test in this embodiment of the invention effectively solves the problems of low production efficiency, equipment corrosion and substandard water quality caused by unreasonable current control during the transition test stage, improves the accuracy and production efficiency of the transition test, and ensures the performance and service life of the EDI membrane block.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for calculating the operating current of a continuous electro-deionization membrane block during transition testing, characterized in that, include: S1, obtain the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and calculate the first operating current I1 based on the number of freshwater chambers and the electrodialysis potential difference, using the following formula: in, The operating current for the transition test of the continuous electrostatic desalination membrane block; With a safety factor of 1, for The ratio of anion and cation exchange resins in the concentrate chamber of the membrane module. for The ratio of anion and cation exchange resins in the desalination chamber of the membrane module. For the potential difference required for membrane electrodialysis, a value of 100-120 is used for a 5-ton capacity membrane module, and 60-80 is used for a 3-ton capacity membrane module. for The number of freshwater chambers in the membrane module. It is Faraday's constant. To produce water for the freshwater chamber value, Water dissociation coefficient , With a safety factor of 2, The range of values ​​is ; S2, obtain the ion exchange resin ratio K1 in the concentrate chamber and K2 in the desalination chamber, and calculate the polarization current I2 based on K1 and K2, using the following formula: in, The polarization current for the transition test of the continuous electro-deionization membrane block is A, where A is the membrane area of ​​a single chamber of the continuous electro-deionization membrane block. Polarization current density of continuous electro-desalination membrane block , The effective current coefficient for the transition test of continuous electrostatic desalination membrane blocks; S3. Compare the first operating current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test operating current; otherwise, I1 is used as the actual transition test operating current. S4. Adjust the power supply output current according to the actual transition test working current, and monitor the pH value at the concentrate chamber outlet and the temperature at the anode chamber outlet in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

2. The method as described in claim 1, characterized in that, The step of comparing the first operating current I1 with the polarization current I2, and if I1 is greater than I2, then I2 is used as the actual transition test operating current; otherwise, I1 is used as the actual transition test operating current, further includes: S31, when I1>I2, I2 is taken as the actual working current, and this current value is recorded as the upper limit of the current for the membrane module transformation test; S32, when I1≤I2, I1 is taken as the actual working current, and the current value is recorded as the current reference for the membrane module transformation test.

3. The method as described in claim 1, characterized in that, Also includes: S5, monitor the resistivity of the freshwater outlet in the freshwater chamber. When the resistivity is greater than or equal to 16... At that time, the produced water is deemed qualified, and the EDI membrane module is judged to have passed the conversion test in combination with whether the test voltage is less than or equal to 150V.

4. A calculation device for the working current of a continuous electro-deionization membrane block transition test, characterized in that, include: The current parameter acquisition module is used to obtain the number of freshwater chambers C and the electrodialysis potential difference of the EDI membrane block, and to calculate the first operating current I1 based on the number of freshwater chambers and the electrodialysis potential difference, using the following formula: in, The operating current for the transition test of the continuous electrostatic desalination membrane module; With a safety factor of 1, for The ratio of anion and cation exchange resins in the concentrate chamber of the membrane module. for The ratio of anion and cation exchange resins in the desalination chamber of the membrane module. For the potential difference required for membrane electrodialysis, a value of 100-120 is used for a 5-ton capacity membrane module, and 60-80 is used for a 3-ton capacity membrane module. for The number of freshwater chambers in the membrane module. It is Faraday's constant. To produce water for the freshwater chamber value, Water dissociation coefficient , With a safety factor of 2, The range of values ​​is ; The polarization current calculation module is used to obtain the ion exchange resin ratio K1 in the concentrate chamber and K2 in the desalination chamber, and to calculate the polarization current I2 based on K1 and K2, using the following formula: in, The polarization current for the transition test of the continuous electro-deionization membrane block is A, where A is the membrane area of ​​a single chamber of the continuous electro-deionization membrane block. Polarization current density of continuous electro-desalination membrane block , The effective current coefficient for the transition test of continuous electrostatic desalination membrane blocks; The current selection and judgment module is used to compare the first working current I1 with the polarization current I2. If I1 is greater than I2, then I2 is used as the actual transition test working current; otherwise, I1 is used as the actual transition test working current. The current control and monitoring module is used to adjust the power supply output current according to the actual transition test working current, and to monitor the pH value at the concentrate chamber outlet and the anode chamber outlet temperature in real time during the transition test. When the pH value is lower than the set threshold or the temperature exceeds 35°C, the current is automatically cut off.

5. The apparatus as described in claim 4, characterized in that, The current selection and judgment module is also used for: When I1>I2, I2 is taken as the actual operating current, and this current value is recorded as the upper limit of the current for the membrane module transition test. When I1≤I2, I1 is taken as the actual operating current, and this current value is recorded as the current reference for the membrane module transformation test.

6. The apparatus as claimed in claim 4, characterized in that, Also includes: The product water monitoring module is used to monitor the resistivity of the freshwater outlet in the freshwater chamber. When the resistivity is greater than or equal to 16... At that time, the produced water is deemed qualified, and the EDI membrane module is judged to have passed the conversion test in combination with whether the test voltage is less than or equal to 150V.

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