Ion exchange membrane-based ph regulation system and method

Abstract

The application belongs to the technical field of chemical industry and environmental protection, and discloses a pH regulation system and method based on ion exchange membrane. The system comprises a data acquisition module, a calculation analysis module and an analysis adjustment module. The method comprises the following steps: S1, data acquisition, collecting the pH value of the receiving liquid; S2, calculation analysis, calculating the ion flux at the data acquisition time of S1; S3, analysis adjustment, comprehensively analyzing the pH value collected in S1 and the ion flux calculated in S2 to obtain an adjustment strategy, and adding the liquid medicine according to the adjustment strategy to realize the pH regulation. The regulation system and method provided by the application can more accurately and timely regulate the pH value of the receiving liquid in the application process of the ion exchange membrane.

Description

Technical Field

[0001] This invention belongs to the field of chemical environmental protection, specifically relating to a pH control system and method based on ion exchange membranes. Background Technology

[0002] Ion exchange membranes have selective permeability to ions in solutions. In the chemical and environmental protection fields, ion exchange membranes are commonly used for solution purification and concentration, such as for wastewater treatment.

[0003] In the application of ion exchange membranes, there is a scenario where one side of the ion exchange membrane is the feed solution and the other side is the receiving solution, which is either an acid or an alkali solution. The target ions in the feed solution pass through the ion exchange membrane into the receiving solution and react with H+ ions in the receiving solution. + or OH - The reaction proceeds to achieve the directional migration of target ions and thus purify the original solution. In this scenario, the pH value of the receiving solution is crucial, as it affects both the ability to receive target ions and the driving force for these ions to pass through the ion exchange membrane (the driving force is positively correlated with the concentration ratio of the two ions exchanged through the ion exchange membrane; in this case, one ion is the target ion, and the other is the H+ ions in the receiving solution). + or OH - Another type of ion, whose concentration is closely related to pH value.

[0004] For example, in an ammonia nitrogen wastewater treatment system using a cation exchange membrane, the raw solution is the ammonia nitrogen wastewater to be treated, and the receiving solution is a NaOH solution. + Driven by this, the NH4 in the original solution + It enters the receiving solution through the cation exchange membrane and reacts with OH-. - The reaction proceeds in a 1:1 ratio, ultimately forming NH3 and Na. + Migrate towards the original solution. The pH of the receiving solution here is similar to that of Na+. + Concentration and OH - Concentration is directly related; when the pH value is low, i.e., OH- - If the concentration is low, the receiving liquid will react with NH4. + The ability to accept ions decreases, and at the same time, Na + Concentration and NH4 + The concentration ratio decreases, NH4 + A decrease in the driving force for migration will directly affect the efficiency and effectiveness of wastewater treatment.

[0005] In the above situation, as the reaction proceeds, H + or OH -The concentration is gradually reduced, and in order to ensure the treatment efficiency and effect, the reagent solution (acid solution or alkali solution) is supplemented to the receiving liquid in the process, so as to maintain the pH value in the ideal range as much as possible.

[0006] In the prior art, the reagent solution is supplemented by manually sampling and detecting the pH value of the receiving liquid, and then the measured value is used for estimation and supplement. This method has the problems of long time interval between measurement and supplement, and the supplement is not timely. In addition, the estimation error is large. According to the actual verification, the value after supplement is difficult to reach the ideal range, and the efficiency and effect of solution treatment are not ideal. SUMMARY

[0007] The present application aims to provide a pH regulation system and method based on ion exchange membrane, so that the pH value of the receiving liquid can be more accurately and timely regulated in the application process of the ion exchange membrane in the background art.

[0008] To achieve the above-mentioned purpose, the present application provides the following basic scheme, a pH regulation method based on ion exchange membrane, comprising the following steps,

[0009] S1, data acquisition, acquiring the pH value of the receiving liquid;

[0010] S2, calculation and analysis, calculating the ion flux at the time of S1 data acquisition;

[0011] S3, analysis and adjustment, comprehensively analyzing the pH value collected in S1 and the ion flux calculated in S2 to obtain an adjustment strategy, and supplementing the reagent solution according to the adjustment strategy to realize the regulation of the pH value.

[0012] The principle and beneficial effects of the technical solution are as follows:

[0013] The prior art is that the system is manually collected to measure the pH value of the receiving liquid, and then the reagent solution is estimated and supplemented to make up for the consumption of H + or OH - . However, when the pH value is measured again after supplementing, it is found that the pH value of the receiving liquid is usually far from the ideal range, and the regulation accuracy can only reach 70%, so that the reagent solution is repeatedly estimated and supplemented. This way of supplementing the reagent solution depends on experience and luck, is not accurate and timely, and is very cumbersome because of repeated sampling, estimation and supplement.

[0014] During the research, the inventor also considered that if the reagent solution is accurately supplemented, the ideal concentration value C 理想 of the receiving liquid is calculated according to the ideal pH value, and then the concentration C1 of the reagent solution is supplemented according to the concentration C0 of the receiving liquid before supplementing and the volume V0, and the equation C0V0+C1V 补 =C 理想 (V0+V 补) to calculate the volume V of the liquid medicine to be added 补 , so as to achieve accurate addition. However, this is only an ideal state. In actual operation, the volumes of the original liquid and the receiving liquid are very large, the tank volume for containing the two solutions is also very large, and the volume of the liquid medicine to be added is relatively very small. After the liquid medicine is added, the change in the volume of the receiving liquid cannot be identified by the existing measuring instrument, i.e. V0+V 补 ≈V0. A small measurement error of V0may cause a large fluctuation of V 补 . Therefore, in actual production, it is almost impossible to accurately calculate V 补 by measuring V0. The fluctuation may be even larger than the estimation.

[0015] The inventor also thought of lengthening the interval time for addition, so that the difference between C0and C 理想 is large, the volume V 补 of the liquid medicine to be added is large, the difference between V0and V 补 is small, and the fluctuation of V 补 caused by the measurement error of V0is reduced, so that V 补 can be more accurately calculated. However, after the interval time is lengthened, the inventor found that the mass transfer efficiency of the ion exchange membrane in the later stage is already very low, which seriously affects the processing efficiency of the system, and thus the end is defeated by the means. The inventor analyzed and speculated that the reason is that the receiving liquid is not supplemented in time, the concentration of the receiving liquid is reduced, the concentration difference on both sides of the ion exchange membrane is reduced, the driving force is reduced, and the mass transfer efficiency is affected. Therefore, this method is also not feasible.

[0016] Later, the inventor thought of the following during the research process. The receiving liquid needs to be supplemented with the liquid medicine because the liquid medicine in the original liquid enters the receiving liquid and consumes H + or OH - in the receiving liquid. If the ion amount passing through the ion exchange membrane, i.e. ion flux x membrane area x time (the ion flux is the ion amount passing through a unit membrane area per unit time), is known, can we calculate the consumed H + or OH - amount from the reaction equation, and thus obtain the amount of the liquid medicine to be added? Therefore, the inventor operated according to this using the ion flux, but the result was not ideal. Through the research and exploration of the inventor, it was found that, first, the ion flux is constantly changing, and we can only measure and calculate the ion flux at a certain moment, but the liquid medicine is added at an interval time. It is not accurate to calculate the ion amount passing through in a reaction interval time using the ion flux at a certain moment. Second, in the operation process of the ion exchange membrane, H + or OH -Besides the ion reaction consumption from the original solution, reverse migration will also occur, which will also cause the decrease of H + or OH - in the receiving solution, which conflicts with the common understanding that ion exchange membranes only allow specific ions to pass through. Therefore, it is not feasible to regulate the pH of the receiving solution by ion flux alone.

[0017] Subsequently, the inventors conducted further in-depth exploration and analysis, and finally obtained the present scheme, that is, by comprehensively analyzing the measured pH value of the receiving solution and the ion flux at the measured pH value, a regulation strategy is obtained, and then the liquor is supplemented according to the regulation strategy after comprehensive analysis, so as to realize the regulation of pH. After the inventors supplemented the liquor in this way, the pH of the receiving solution was measured again, and the pH value was almost within the ideal range.

[0018] Further, in S3, the pH value and ion flux of the receiving solution are comprehensively analyzed according to a preset standard, and the preset standard is the relationship among the pH value pH 测 , the standard upper limit value pH 上限 or the standard lower limit value pH 下限 of the pH of the receiving solution, and the pH calculation value pH 算 of the ideal driving force of the receiving solution, to obtain different regulation strategies based on ion flux.

[0019] Beneficial effects: The inventors analyzed the experimental results and found that for the receiving solution, if the pH exceeds a certain upper limit or lower limit, the operation of the entire system will be greatly affected, and the mass transfer efficiency will be significantly reduced. Here, if the receiving solution is an acid solution, the standard upper limit value of pH is pH 上限 ; if the receiving solution is an alkali solution, the standard lower limit value of pH is pH 下限 . The driving force of the receiving solution is positively correlated with the concentration ratio of the two ions exchanged through the ion exchange membrane, so the pH value of the receiving solution should be what, that is, pH 算 , according to the calculation of the ideal driving force. By comprehensively analyzing the relationship among the three, a precise regulation strategy based on ion flux can be obtained.

[0020] Further, in S1, the ion concentration of the original solution to be exchanged through the ion exchange membrane is also collected, and in S2, the pH calculation value pH 算 under the ideal driving force of the receiving solution is also calculated according to the ion concentration.

[0021] Beneficial effects: The driving force of the receiving solution is positively correlated with the concentration ratio of the two ions exchanged through the ion exchange membrane, the ion concentration of the original solution to be exchanged through the ion exchange membrane is determined, and the ideal driving force is determined, so the concentration of the receiving solution under the driving force can be calculated, and then the pH 算 can be calculated.

[0022] Further, the ion exchange membrane is a cation exchange membrane, the stock solution on one side of the cation exchange membrane is ammonia-nitrogen wastewater containing NH4 + , the receiving solution on the other side is NaOH solution, and the ion flux is NH4 + flux.

[0023] Beneficial effects: the scheme limits the above-mentioned scheme to a specific application scenario.

[0024] Further, the preset standard is,

[0025] when pH 下限 <pH 算 <pH 测 , V 补 =V 设 ;

[0026] when pH 下限 <pH 测 <pH 算 , V 补 =V 设 ×1.2;

[0027] when pH 测 <pH 下限 <pH 算 , V 补 =V 设 ×2;

[0028] when pH 算 <pH 下限 <pH 测 , V 补 =V 设 ;

[0029] when pH 算 <pH 测 <pH 下限 , V 补 =V 设 ×1.2;

[0030] when pH 测 <pH 算 <pH 下限 , V 补 =V 设 ×1.5;

[0031] wherein V 补 is the amount of the added liquor, and V 设 is the theoretical amount of the liquor calculated according to NH4 + flux.

[0032] Beneficial effect: the scheme shows the specific content of the preset standard in the above specific application scene. Under this preset standard, the effect of liquid supplement is ideal, and after supplement, the pH of the received liquid is measured, and the pH value is almost in the ideal range.

[0033] Further, NH4 + The calculation method of flux is NH4 + Flux = -1.03lnt + 5.7124, wherein t is the running time of the system, the unit of t is h, NH4 + The unit of flux is mg / m 2 .h.

[0034] Beneficial effect: according to the experimental analysis of the inventor, NH4 + Flux is calculated according to the method of the scheme, and the adjustment strategy obtained by combining the preset standard in the foregoing scheme is ideal. Wherein t is the duration from the start of the system operation and the start of the ion exchange membrane operation.

[0035] Further, the ideal driving force is ρ = c (Na + ) / c (NH4 + ), 1 ≤ ρ ≤ 4, wherein c (Na + ) is the Na + concentration in the received liquid, and c (NH4 + ) is the NH4 + concentration in the original liquid.

[0036] Beneficial effect: according to the research of the inventor, when 1 ≤ ρ ≤ 4, the mass transfer efficiency is high.

[0037] Further, the interval time of S1 data acquisition is 0.5-1h.

[0038] Beneficial effect: the interval time here refers to how long to measure data and perform control once. If the interval time is too long, the overall processing efficiency will be affected, if the interval time is too short, the amount of liquid supplement is very small, and the effect of supplement is not obvious, which increases the cost of manpower, equipment operation and the like caused by supplement.

[0039] Further, pH 下限 = 9.25.

[0040] Beneficial effect: controlling the pH 下限 to this value can ensure that the received liquid has good receiving capacity.

[0041] To achieve the above object, the present application provides another basic scheme as follows, a pH control system based on ion exchange membrane, executing any of the foregoing pH control methods, comprising,

[0042] A data acquisition module is configured to perform S1 and acquire parameters of each link in a running process in real time.

[0043] A calculation analysis module is configured to perform S2 and calculate an ion flux through the ion exchange membrane or a pH calculation value pH 算 of the receiving liquid under an ideal driving force in real time.

[0044] An analysis adjustment module is configured to perform S3, comprehensively analyze the pH value of the receiving liquid and the ion flux, obtain an adjustment strategy, and automatically add a reagent according to the adjustment strategy, so as to realize intelligent regulation and control of the pH.

[0045] Beneficial effects: Based on accurate regulation and control of the pH, the scheme can realize intelligent regulation and control, and the regulation and control is more accurate and timely through the system. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 FIG. 1 is a block schematic diagram of a pH regulation system based on an ion exchange membrane in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The present application will be further described in detail through specific embodiments.

[0048] The present embodiment provides a pH regulation method based on an ion exchange membrane, which comprises the following steps:

[0049] S1, data acquisition, acquiring a pH value of a receiving liquid and an ion concentration value of a raw liquid to be passed through the ion exchange membrane;

[0050] S2, calculation analysis, calculating an ion flux at a data acquisition time of S1, and calculating a pH calculation value pH 算 of the receiving liquid under an ideal driving force according to the ion concentration value acquired in S1.

[0051] S3, analysis adjustment, comprehensively analyzing the pH value acquired in S1 and the ion flux calculated in S2 according to a preset standard, obtaining an adjustment strategy, and adding a reagent according to the adjustment strategy, so as to realize regulation and control of the pH, wherein the preset standard is a relationship among the pH value pH 测 acquired in S1, a standard upper limit value pH 上限 or a standard lower limit value pH 下限 of the pH of the receiving liquid, and the pH calculation value pH 算 of the ideal driving force of the receiving liquid, so as to obtain different adjustment strategies based on the ion flux. If the receiving liquid is an acid liquid, the standard upper limit value pH 上限 of the pH is obtained; if the receiving liquid is an alkali liquid, the standard lower limit value pH 下限 of the pH is obtained.

[0052] The ion exchange membrane described herein can be a cation exchange membrane or an anion exchange membrane. If it is a cation exchange membrane, the ions in the raw solution to be passed through the cation exchange membrane are cations, the ion flux is also the flux of cations, and the receiving solution is an alkali solution; if it is an anion exchange membrane, the ions in the raw solution to be passed through the anion exchange membrane are anions, the ion flux is also the flux of anions, and the receiving solution is an acid solution.

[0053] The ion exchange membrane in this embodiment is a cation exchange membrane, specifically a TWDD-60-100B, purchased from Shandong Tianwei Membrane Technology Co., Ltd. The raw solution on one side of the cation exchange membrane is ammonia-nitrogen wastewater containing NH4 + , the concentration of NH4 + is 50 mg / L, the receiving solution on the other side is a NaOH solution with a concentration of 0.0056 mol / L, the ion flux is the flux of NH4 + , and the specific scenario is to enrich NH4 + in ammonia-nitrogen wastewater by passing through the cation exchange membrane, thereby achieving wastewater treatment. The principle is that under the driving of Na + , NH4 + in the raw solution passes through the cation exchange membrane into the receiving solution and reacts with OH - in a 1:1 ratio, finally forming NH3, and at the same time, Na + migrates to the raw solution.

[0054] In this process, the pH value of the receiving solution is positively correlated with the concentration of the NaOH solution, and the concentration of the NaOH solution directly affects the receiving capacity for NH4 + and the driving force for the migration of NH4 + . If the pH value is too small, i.e. the concentration of the NaOH solution is too low, the driving force for the migration of NH4 + is small, the overall treatment efficiency is low, and the ability of the NaOH solution to receive NH4 + and react to form NH3 is also low; if the pH value is too large, i.e. the concentration of the NaOH solution is too high, it will cause greater damage to the cation exchange membrane. Therefore, the pH value of the receiving solution needs to be stably controlled within a desired range, which neither causes great damage to the cation exchange membrane nor loses good receiving capacity for NH4 + , and also retains a good driving force for the migration of NH4 + . Through the research and analysis of the inventor, this desired range is 11.5-12.5.

[0055] To achieve stable control within the above-mentioned desired range, on the basis of the above-mentioned pH control method, the following settings are made.

[0056] The preset standard is set as:

[0057] When pH 下限 < pH 算 < pH 测 , V 补 = V 设 ;

[0058] When pH 下限 < pH 测 < pH 算 , V 补 = V 设 x 1.2;

[0059] When pH 测 < pH 下限 < pH 算 , V 补 = V 设 x 2;

[0060] When pH 算 < pH 下限 < pH 测 , V 补 = V 设 ;

[0061] When pH 算 < pH 测 < pH 下限 , V 补 = V 设 x 1.2;

[0062] When pH 测 < pH 算 < pH 下限 , V 补 = V 设 x 1.5.

[0063] Wherein, V 补 is the amount of the liquid to be added, the value of which is the adjustment strategy we want to get finally; V 设 is the theoretical amount of the liquid to be added according to NH4 + flux.

[0064] According to the research of the inventor, in this case, pH 下限 is set to 9.25, which can ensure that the receiving liquid has good receiving capacity and good driving force.

[0065] The calculation method of NH4 + flux is NH4 + flux = -1.03lnt + 5.7124, t is the running time of the system, the unit of t is h, and the unit of NH4 + flux is mg / m 2 .h. The NH4+ Flux, V 设 The calculation method is: n 设 (NaOH)=n 设 (OH - )=n 设 (NH4 + )= NH4 + Flux × Membrane Area × Dosing Interval Time / 0.018 mol, V 设 = n (NaOH) / C1. Here, n 设 (NaOH), n 设 (OH - ), and n 设 (NH4 + ) respectively refer to the amount of substance of NaOH, OH - , and NH4 + , and the unit is mol; C1 is the concentration of the concentrated alkali solution, i.e. the concentration of the NaOH solution to be added, and the unit is mol / L, and V 设 the unit is L.

[0066] Ideal driving force ρ = c (Na + ) / c (NH4 + ), wherein c (Na + ) is the Na + concentration in the receiving liquid, and c (NH4 + ) is the NH4 + concentration in the original liquid. According to experiments, the inventors determined that when 1 ≤ ρ ≤ 4, the mass transfer efficiency is relatively high, and especially when ρ is set to 2, the overall effect is relatively good, which can ensure the mass transfer efficiency and will not cause excessively high alkali concentration, thereby causing waste of alkali. When ρ is determined, during S1 data collection, the concentration c (NH4 + ) of NH4 + is collected, and c (Na + ) = c (NH4 + ) × ρ, c1 (OH - ) = c1 (NaOH) = c1 (Na + ) = c (Na + ) / 0.023 are calculated, and thus according to pH = -lg c (H + ), c (H + ) × c (OH - ) = Kw, it is obtained that pH 算 = -lg 【0.023Kw / c (Na + 】. c (H + ), c (OH - ), c (Na + ), c (NH4 +mg / L, c1(OH - ), c1(NaOH), c1(Na + ) are all in mol / L.

[0067] In this embodiment, the interval time of S1 data collection is set to 0.75h, which means collecting the pH value of the receiving liquid pH 测 and the concentration of NH4 + in the raw liquid c(NH4 + ) every 0.75h, and then adding the chemical liquid, i.e. the concentrated NaOH solution, to regulate the pH value of the receiving liquid, which has a good effect and can keep the pH value of the receiving liquid in an ideal range.

[0068] To more intelligently implement the above method, the embodiment also provides a pH regulation system based on ion exchange membrane, as shown in FIG. 3, which includes a data collection module 1, a calculation analysis module 2 and an analysis adjustment module 3. Figure 1

[0069] The data collection module 1 is used to execute S1 and collect the parameters in each link of the system operation in real time. The first input unit and the first collection unit are arranged in the module. The first input unit is used to input command information, such as the type of collected parameters and the interval time of collected parameters. In the implementation process of the embodiment, the collected parameters include the pH value of the receiving liquid, i.e. the NaOH solution, and the concentration of NH4 + in the raw liquid, i.e. the ammonia-nitrogen-containing wastewater. The interval time of collected parameters is 0.75h, i.e. collecting data every 0.75h. The first collection unit is used for the execution of data collection, including a concentration detector and a pH detector. In the embodiment, the Hash Amtax NA8000 water quality detector is used to collect the concentration of NH4 + in the raw liquid, i.e. the ammonia-nitrogen-containing wastewater, and the Hash GLIpH / ORP analyzer is used to collect the pH value of the receiving liquid, i.e. the NaOH solution.

[0070] The calculation analysis module 2 is used to execute S2 and calculate the ion flux through the ion exchange membrane or the pH calculation value pH 算 under the ideal driving force of the receiving liquid in real time. The module is built-in with the algorithm described above, including the algorithm of ion flux, the algorithm of calculating the theoretical addition amount V 设 of the chemical liquid through the ion flux, and the pH calculation value pH 算 ​, the data acquisition module 1 will be called. The calculation analysis module 2 is also provided with a second input unit and a time recording unit. The second input unit is used to input command information, such as receiving liquid ideal driving force p. In the implementation process of the embodiment, p is set to 2, and of course the value of p can be modified through the second input unit. The time recording unit is used to record the running time t of the system, and the time t will be called when calculating the ion flux. In addition, when the calculation analysis module 2 runs the algorithm of the theoretical liquid supplement amount V 设 of the drug, the interval time of the data acquisition module 1, that is, the drug adding interval time in the algorithm, will also be called. It is worth noting that the supplement of the liquid will be carried out once for each data acquisition, so the interval time of the data acquisition is consistent with the interval time of the drug adding.

[0071] The analysis and adjustment module 3 is used to execute S3, and the pH value and ion flux of the receiving liquid are comprehensively analyzed to obtain the adjustment strategy, and the liquid is automatically supplemented according to the adjustment strategy to realize the intelligent control of the pH. The above-mentioned preset standard is built in the module, and the pH value and ion flux of the receiving liquid are comprehensively analyzed according to the preset standard. The module also includes a third input unit and a liquid supplement unit. The third input unit is used to input command information, such as pH 下限 , and pH 下限 can be modified through the third input unit. The liquid supplement unit is used to execute the liquid supplement, including the Agilent APG 603 pump. It is worth noting that when the module runs, the data of the data acquisition module 1 and the calculation analysis module 2 will be called for comprehensive analysis according to the preset standard.

[0072] In order to verify and monitor the pH value of the receiving liquid after drug replenishment, this embodiment of the pH control system based on ion exchange membrane also includes a verification module 4, which is used to collect and verify the pH value of the receiving liquid after drug replenishment. The verification module 4 includes a fourth input unit and a second acquisition unit. The fourth input unit is used to verify the input of command information. In this embodiment, the interval between the verification data acquisition and the parameter acquisition in the data acquisition module 1 needs to be input. For example, if the interval between the parameter acquisition in the data acquisition module 1 is 1 hour, and the interval between the verification data acquisition and the parameter acquisition in the data acquisition module 1 is 0.1 hours, then starting from the start of system operation, the time points for parameter acquisition in the data acquisition module 1 are 1 hour, 2 hours, 3 hours, 4 hours, 5 hours... and the time points for verification data acquisition in the verification module 4 are 1.1 hours, 2.1 hours, 3.1 hours, 4.1 hours, 5.1 hours... In this embodiment, the interval between the verification data acquisition and the parameter acquisition in the data acquisition module 1 is 30 seconds. This interval can be modified through the fourth input unit. It is worth noting that both the container holding the original solution and the receiving solution are equipped with stirrers to continuously stir the solution. The second acquisition unit is used to verify the execution of data acquisition. Specifically, it is a pH meter that acquires the pH value of the receiving liquid. In this embodiment, a Hach GLI pH / ORP analyzer is used. It can be shared with the Hach GLI pH / ORP analyzer in data acquisition module 1, or it can be set up separately. In this embodiment, it is shared with the Hach GLI pH / ORP analyzer in data acquisition module 1.

[0073] To facilitate monitoring of the control effect, the fourth input unit is also used to input the ideal range of pH value of the receiving liquid. After the second acquisition unit collects and verifies the data, it compares and analyzes it with the ideal range. If the data is not within the ideal range, it is marked so that the operators can easily view it.

[0074] The control scheme in this embodiment achieves an accuracy rate of over 95%. The accuracy rate is calculated as: (Number of times the pH of the receiving solution is within the ideal range after control) / (Total number of control cycles). Whether the pH of the receiving solution is within the ideal range after control is determined by verification data collected by verification module 4. Alternatively, manual verification data can be collected after control. Furthermore, approximately 30 seconds after the drug is added, the NH4+ in the original solution is collected. + Concentration and Na in the receiving liquid + The driving force is calculated based on the concentration, and it meets the requirements in more than 99.9% of cases, that is, it is greater than or equal to the set ideal driving force. In this embodiment, it is 2. In particular, the driving force also meets the requirements for the part where the pH value of the receiving liquid fails to reach the ideal range after adjustment.

[0075] For those skilled in the art, without departing from the technical scheme concept of the present application, several modifications and improvements can be made, which should be considered as the protection scope of the present application, and these will not affect the effect and practicality of the patent implementation.

Claims

1. A method for pH control based on ion exchange membranes, characterized in that: Comprising the following steps, S1, data acquisition, collecting the pH value of the receiving liquid; S2, calculation and analysis, calculating the ion flux at the time of S1 data acquisition; S3, analysis and adjustment, comprehensively analyzing the pH value collected in S1 and the ion flux calculated in S2 to obtain an adjustment strategy, and adding the liquid medicine according to the adjustment strategy to realize the pH control; In step S3, the pH value and ion flux of the receiving liquid are comprehensively analyzed according to a preset standard. The preset standard is based on the pH value collected in step S1. 测 The upper limit of the standard pH value of the receiving solution 上限 Or the lower limit of the standard pH 下限 Calculated pH value of the ideal driving force of the receiving liquid 算 The relationship between the three factors leads to different regulation strategies based on ion flux. In S1, the ion concentration of the solution to be passed through the ion exchange membrane is also collected, and in S2, the pH value pH 算 calculated under the ideal driving force of the receiving solution is also calculated according to the ion concentration. The ion exchange membrane is a cation exchange membrane, the stock solution on one side of the cation exchange membrane is ammonia-nitrogen wastewater containing NH4 + , the receiving solution on the other side is NaOH solution, and the ion flux is NH4 + flux. The preset standard is, When pH 下限 < pH 算 < pH 测 V 补 = V 设 ; When pH 下限 < pH 测 < pH 算 V 补 = V 设 x 1.2; When pH 测 When pH 下限 When pH 算 V 补 = V 设 × 2; When pH 算 < pH 下限 < pH 测 V 补 = V 设 ; When pH 算 < pH 测 < pH 下限 V 补 = V 设 x 1.2; When pH 测 < pH 算 < pH 下限 V 补 = V 设 x 1.5; where V 补 is the amount of make-up liquor, V 设 is the theoretical make-up amount of liquor calculated from NH4 + flux; NH4 + The flux is calculated as follows: NH4 + Flux = -1.03ln t + 5.7124, where t is the time of system operation, t is in h, NH4 + The unit of flux is mg / m 2 .h, V 设 The calculation method is as follows: n 设 (NaOH) = n 设 (OH - ) = n 设 (NH4 + ) = NH4 + Flux x Membrane Area x Dosing Interval Time / 0.018, V 设 = n (NaOH) / Cl; The ideal driving force p = c(Na + ) / c(NH4 + ), 1≤p≤4, wherein c(Na + ) is the Na + concentration in the receiving liquid, c(NH4 + ) is the NH4 + concentration in the original liquid, the unit is mg / L, and pH 算 = -lg[0.023Kw / c(Na + )].

2. The ion-exchange membrane-based pH regulation method according to claim 1, characterized by: The interval time of S1 data acquisition is 0.5-1h.

3. The ion-exchange membrane-based pH modulation method according to claim 2, characterized by: pH 下限 = 9.

25.

4. A pH regulating system based on ion exchange membranes, characterized by: The method of any one of claims 1-3, comprising, A data acquisition module for executing S1 to collect the parameters of each link in the running process in real time; a calculation analysis module for performing S2, calculating the ion flux through the ion exchange membrane and the pH calculated value pH under the ideal driving force of the receiving liquid in real time 算 ; An analysis and adjustment module for executing S3 to comprehensively analyze the pH value and ion flux of the receiving liquid, obtain an adjustment strategy, and automatically add the liquid medicine according to the adjustment strategy to realize the intelligent pH control.

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