Method and system for analyzing excess alkali amount of saline water

Abstract

The invention relates to the technical field of chemical engineering, and discloses a salt water excess alkali amount analysis method and analysis system.The analysis method comprises the steps that salt water is titrated through a standard acid titration unit, and the excess alkali amount in the salt water is obtained according to the standard acid volume consumed when the salt water is titrated to a target titration point; wherein the target dropping points at least comprise a first dropping point with the pH value of 7.6-8.5, a second dropping point with the pH value of 3.9-4.5 and a third dropping point between the first dropping point and the second dropping point; the titration speed U3 of titration to the third titration point is controlled to be greater than the titration speed of titration to the first titration point and / or the second titration point. According to the invention, a plurality of titration points are arranged, the titration speed is controlled in a segmented manner, the speed is reduced in a key end point region to improve the judgment precision, the speed is improved in a non-key region to shorten the detection time, the detection period is effectively compressed while excessive titration is avoided, and both the detection precision and the detection efficiency are realized.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method and system for analyzing the excess alkalinity of brine. Background Technology

[0002] In chlor-alkali production, the sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) content in brine is a crucial indicator of its alkalinity. Stable control of excess alkali significantly impacts electrolysis efficiency, ion-exchange membrane lifespan, and product quality. Currently, industry monitoring of NaOH and Na2CO3 content relies primarily on manual analysis, which is time-consuming, labor-intensive, and lacks real-time accuracy, making it difficult to promptly reflect production status and guide process adjustments.

[0003] Although some factories have equipped themselves with online analyzers to replace manual testing, problems such as long testing times and insufficient accuracy still exist in actual operation. Especially under complex operating conditions such as high salt, high impurity, and strong corrosion, the adaptability and long-term stability of the equipment are difficult to guarantee. These factors restrict the chlor-alkali industry from achieving efficient automation and lean production in the brine refining process. Therefore, there is an urgent need for an automated testing solution that can operate stably under complex conditions and provide high-precision, low-cost, real-time monitoring of NaOH and Na2CO3 content. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, such as long detection cycle and high labor intensity of manual detection of excess alkali, and long detection time, low accuracy, poor adaptability and insufficient long-term stability of existing online analyzers, so as to provide a method and system for analyzing excess alkali in brine.

[0005] According to an embodiment of the present invention, in a first aspect, a method for analyzing the excess alkalinity of brine is provided, comprising: titrating brine using a standard acid titration unit, and obtaining the excess alkalinity in the brine based on the volume of standard acid consumed in titration to a target titration point; The target titration point includes at least a first titration point with a pH of 7.6 to 8.5, a second titration point with a pH of 3.9 to 4.5, and a third titration point between the first and second titration points; The titration rate U3 is controlled to be greater than the titration rate to the first and / or second titration points.

[0006] This invention, by setting multiple titration points during the titration process and employing differentiated titration rates at different titration stages, can reduce the titration rate near the first and second titration points to ensure the accuracy of endpoint determination, while increasing the titration rate during titration towards the third titration point, thereby shortening the analysis time in non-critical stages. This technical solution avoids overshoot errors caused by excessively high titration rates in the critical endpoint region, while also reducing the overall detection cycle, achieving a balance between detection accuracy and efficiency. It is suitable for automated analysis and real-time monitoring of excess alkalinity in brine under complex conditions such as high salinity and high impurities.

[0007] In some optional embodiments, the target titration point further includes an initial titration point with a pH of 9.8–10.5, and the titration rate U is controlled to titrate to the initial titration point. 初 A titration rate greater than the titration rate to the first titration point and / or the second titration point; Preferably, the titration rate U is controlled. 初 It is greater than the titration rate U3.

[0008] An initial titration point with a pH of 9.8–10.5 is introduced during the titration process, and a higher titration rate is used at this stage than at other stages. This allows the sample to rapidly approach the critical reaction range from its initial state, significantly shortening the preparation time and improving overall analytical efficiency. Simultaneously, by controlling U… 初 Titration speeds greater than U3, and U3 greater than the first and second titration points, can maintain a lower speed in the critical endpoint range to improve the accuracy of endpoint determination, while using a higher speed in the non-critical range to accelerate the titration process. This allows for further compression of the detection cycle without reducing measurement accuracy, thus achieving an optimized balance between analytical efficiency and detection accuracy.

[0009] In some optional implementations, a set time interval t is set between titrations to each target titration point. 间隔 Then, perform the next titration. Preferably, the interval is set to a time t. 间隔 It is 0.32 to 2 times the titration time corresponding to titration to a target titration point.

[0010] Preferably, the interval setting time t is 30 seconds.

[0011] During titration, setting an interval after each target titration point before proceeding to the next stage of titration ensures that the solution system is fully mixed and reaches a stable state before entering the next titration step, thereby reducing the risk of misjudging the endpoint due to uneven reaction of the solution or pH fluctuations.

[0012] Furthermore, setting the interval time to 0.32 to 2 times the titration time of the corresponding stage can avoid the extension of the detection cycle caused by excessive waiting while ensuring reaction equilibrium, thus achieving a balance between detection stability and detection efficiency.

[0013] In some alternative implementations, if air bubbles are present in the reservoir of the standard acid titration unit before titration begins, the standard acid titration unit is controlled to purge the air bubbles before titration.

[0014] This invention avoids empty strokes and instantaneous pulse flow caused by air bubbles in the storage pipeline of the standard acid titration unit by prioritizing the removal of air bubbles before titration, ensuring that the theoretical addition amount is consistent with the actual addition volume, thereby improving the volume addition accuracy and making the titration endpoint identification clearer and more stable.

[0015] In some optional embodiments, the titration includes: injecting saline solution into the reaction vessel, and then controlling a standard acid titration unit to inject standard acid into the reaction vessel for titration; The air venting process includes: before injecting brine into the reaction vessel, controlling the standard acid titration unit to inject standard acid into the reaction vessel, and then venting it out of the reaction vessel.

[0016] In some alternative embodiments, the reaction vessel used for titration is connected to a water washing unit. If the brine contains insoluble impurities, the water washing unit is controlled to introduce water into the reaction vessel to wash the reaction vessel before titration begins.

[0017] For saline samples containing insoluble impurities, this invention first washes the reaction vessel with water via a water washing unit before formal titration. This removes solid particles and residues adhering to and deposited on the inner surface of the reaction vessel, resulting in more uniform mixing, a smoother titration curve, and clearer endpoint determination during the titration process. Furthermore, it reduces the risk of cross-contamination and clogging between different batches of samples, thereby improving the accuracy of the measurement results.

[0018] In some alternative implementations, before titration begins, the reaction vessel is first rinsed with brine by introducing brine into it.

[0019] According to an embodiment of the present invention, in a second aspect, a brine excess alkalinity analysis system is provided, which is controlled using the analysis method of the present invention. The analysis system includes: A reaction vessel, a standard acid titration unit connected to the reaction vessel, and a brine input unit; The controller is electrically or communicatively connected to the standard acid titration unit and the saline input unit. The controller controls the brine input unit to input the brine to be tested into the reaction vessel, and controls the standard acid titration unit to inject standard acid into the reaction vessel to titrate the brine to be tested. The volume of standard acid consumed in the titration to the target titration point is used to obtain the amount of excess alkali in the brine.

[0020] In some alternative embodiments, the reaction vessel is connected to a water washing unit, which is connected to the controller; The controller controls the water washing unit to introduce water into the reaction vessel to wash the reaction vessel.

[0021] In some optional embodiments, the reaction vessel is connected to a drainage unit, and the controller is connected to the drainage unit to control the drainage unit to drain the liquid from the reaction vessel; Preferably, the reaction vessel is equipped with a stirring device.

[0022] The technical solution of this invention has the following advantages: This invention, by setting multiple titration points during the titration process and employing differentiated titration rates at different titration stages, can reduce the titration rate near the first and second titration points to ensure the accuracy of endpoint determination, while increasing the titration rate during titration towards the third titration point, thereby shortening the analysis time in non-critical stages. This technical solution avoids overshoot errors caused by excessively high titration rates in the critical endpoint region, while also reducing the overall detection cycle, achieving a balance between detection accuracy and efficiency. It is suitable for automated analysis and real-time monitoring of excess alkalinity in brine under complex conditions such as high salinity and high impurities.

[0023] Additional aspects and advantages of the embodiments of the present invention will be described and shown in part in the following description, or illustrated by practice of the embodiments of the present invention. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the assembly structure of the brine superalkali analysis system of the present invention; Figure 2 This is a flowchart of a method for analyzing the excess alkalinity of brine according to the present invention.

[0026] Figure label: 1. Brine inlet pipe; 11. First transfer pump; 2. Reaction vessel; 3. Storage pipe; 31. Second transfer pump; 4. Water inlet pipe; 41. Third transfer pump; 5. Drain pipe; 51. Fourth transfer pump. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This embodiment provides a brine excess alkalinity analysis system and a brine excess alkalinity analysis method.

[0029] like Figure 1 As shown, the brine excess alkali analysis system includes a reaction vessel, a standard acid titration unit, a brine input unit, a water washing unit, a drainage unit, a pH detection device, and a controller. The controller is electrically or communicatively connected to the standard acid titration unit, the brine input unit, the water washing unit, the drainage unit, and the pH detection device.

[0030] The brine input unit includes a brine input pipe 1 and a first delivery pump 11 installed on the brine input pipe 1. The inlet of the brine input pipe is connected to the main brine pipe, and the outlet of the brine input pipe is connected to the reaction vessel 2. The controller is connected to the first delivery pump 11, and the controller controls the first delivery pump 11 to turn on, inputting the brine to be tested into the reaction vessel.

[0031] The standard acid titration unit includes a standard acid storage tank and a storage pipeline 3. The inlet of the storage pipeline 3 is connected to the standard acid storage tank, and the outlet is connected to the reaction vessel. A second delivery pump 31 is installed on the storage pipeline. A controller is connected to the second delivery pump 31, and the controller controls the second delivery pump 31 to turn on, inputting standard acid into the reaction vessel 2.

[0032] The pH detection device is installed inside the reaction vessel. The pH detection device is a pH electrode. During the titration process, the pH electrode collects potential data at a frequency of seconds and converts the collected signal into a pH value through the signal processing module of the controller, so as to realize rapid and accurate monitoring of acid-base changes in the reaction system.

[0033] The water washing unit includes a water inlet pipe 4, with the inlet connected to a water source and the outlet connected to the reaction vessel 2. A third delivery pump 41 is installed on the water inlet pipe 4. A controller is connected to the third delivery pump 41, and the controller controls the third delivery pump 41 to turn on and inject water into the reaction vessel 2.

[0034] The reaction vessel 2 is equipped with a stirring device. A controller is connected to the power system of the stirring device to control its stirring and maintain the homogeneity of the reaction system. The drainage unit includes a drainage pipe 5. The inlet of the drainage pipe 5 is connected to the reaction vessel, and the outlet is used to drain the liquid from the reaction vessel. A fourth delivery pump 51 is installed on the drainage pipe 5. The controller is connected to the fourth delivery pump 51 and controls the fourth delivery pump 51 to open, thereby draining the liquid from the reaction vessel.

[0035] The brine superalkalinity analysis system provided by this invention also includes a touch control unit, which provides an editable human-machine interface, allowing users to set parameters and configure functions according to their needs. The system adopts modular program control, supporting independent start and stop of each functional module, thereby achieving more flexible operation and higher system scalability.

[0036] This invention uses a precision metering peristaltic pump as the delivery pump to add reagents such as hydrochloric acid, standard acid, and pure water in a stepwise, quantitative, and precise manner, thereby ensuring the accuracy and controllability of the reagent addition process.

[0037] The brine excess alkalinity analysis system provided by this invention combines a reaction vessel, a standard acid titration unit, a brine input unit, a water washing unit, a drainage unit, a pH detection device, and a controller to achieve fully automated operation of the entire process of brine sample collection, automatic titration, real-time monitoring, cleaning, and drainage.

[0038] The brine superalkalinity analysis system provided by this invention uses a precision metering pump to quantitatively deliver reagents such as brine, standard acid, and pure water, ensuring the accuracy and controllability of the liquid addition process. A stirring device is installed inside the reaction vessel to maintain the homogeneity of the reaction system. A pH electrode collects potential data at a frequency of seconds and outputs the pH value after signal processing, enabling rapid and accurate monitoring of acid-base changes in the reaction system.

[0039] This invention uses a controller to centrally control each unit, reducing manual intervention and avoiding the problems of long detection cycles, reliance on experience for endpoint determination, and large human errors in traditional operations. It also enables automatic washing and drainage, ensuring continuous system operation and long-term stability. The system maintains high efficiency, stability, and accuracy even under complex operating conditions, making it suitable for real-time, high-precision, and low-cost online monitoring of excess alkalinity in brine within the chlor-alkali industry. This significantly improves the automation level and lean management capabilities of the production process.

[0040] The method for analyzing the excess alkalinity of brine in this invention includes the following steps: S1, Begin; S2. Control the brine input unit to input the brine to be tested into the reaction vessel; Specifically, the controller controls the first delivery pump to turn on, inputting the brine to be tested into the reaction vessel; S3. Control the standard acid titration unit to input hydrochloric acid into the reaction vessel for titration; Specifically, the controller activates the second delivery pump to introduce standard acid into the reaction vessel; during the titration process, the controller controls the pH detection device to detect the pH value inside the reaction vessel. In this invention, the second delivery pump is first controlled to operate at a titration rate U. 初 Hydrochloric acid is introduced into the reaction vessel until titration reaches the initial titration point with a pH of 9.8 to 10.5. The initial titration point can be set individually, for example, the pH of the initial titration point can be set to 9.8, 10, or 10.5. After reaching the initial titration point, control the second delivery pump to pause for a set time t. 间隔01 ; Subsequently, the second delivery pump is turned on, and titration is performed at the first titration rate U1 to the first titration point with a pH value of 7.6 to 8.5; the first titration point can be set individually, for example, the pH value of the first titration point can be set to 7.6, 8, or 8.5; After reaching the first titration point, control the second delivery pump to pause for a set time t. 间隔02 ; Subsequently, the second delivery pump is turned on, and titration is performed at the third titration rate U3 to the third titration point with a pH value of 6 to 7; the third titration point can be set individually, for example, the pH value of the third titration point can be set to 6, 6.5, or 7; After reaching the third titration point, control the second delivery pump to pause for a set time t. 间隔03 ; Subsequently, the second delivery pump is turned on, and titration is performed at the second titration rate U2 to a second titration point with a pH value of 3.9 to 4.5; the second titration point can be set independently, for example, the pH value of the second titration point can be set to 3.9, 4.0, or 4.5; Once the second titration point is reached, the second delivery pump is shut down.

[0041] In this invention, the titration rate U 初 The third titration speed U3 is greater than the first titration speed U1 and the second titration speed U2. For example: titration speed U 初 The titration rate is 8 ml / min, the third titration rate U3 is 5 ml / min, and the first titration rate U1 and the second titration rate U2 are 3 ml / min.

[0042] In this invention, the pause time t is set. 间隔01 Pause setting time t 间隔02 Pause setting time t 间隔03It is 0.32 to 2 times the titration time corresponding to titration to a target titration point.

[0043] In this invention, hydrochloric acid is used as the standard acid to titrate and detect NaOH and Na2CO3 in saline solution. The first titration point, for example, pH=8.3, is the first stoichiometric point, which is equivalent to all NaOH and half of Na2CO3 being neutralized. The volume V1 of hydrochloric acid consumed from the initial titration point to the first titration point is recorded. Continue titrating to the second titration point, for example, pH=3.9 is the second stoichiometric point, which is equivalent to the other half of Na2CO3 being neutralized. Record the volume of hydrochloric acid V2 consumed from the first titration point to the second titration point. The chemical reaction occurring at the first titration point is as follows: NaOH + HCl = H₂O + NaCl; Na₂CO₃ + HCl = NaHCO₃ + NaCl; The chemical reaction that occurs from the first titration point to the second titration point is as follows: NaHCO3 + HCl = CO2 + H2O + NaCl; The formulas for calculating the concentrations of NaOH and Na2CO3 in the saline solution to be tested are as follows: NaOH = ((V1- V2) ×c× 40) / V + b1; Na2CO3= (2× V2× c× 52.99) / V + b2; Where c is the concentration of hydrochloric acid, V is the volume of the saline solution to be tested, and b1 and b2 are calibration intercepts, which are the differences between the laboratory chemical titration test results and the instrument test results.

[0044] In this invention, if air bubbles are detected in the storage pipeline of the standard acid titration unit before titration begins, the controller will control the standard acid titration unit to perform the air bubble removal operation first before proceeding to the titration step.

[0045] The method for removing air bubbles is as follows: before injecting the saline solution to be tested into the reaction vessel, the second delivery pump is turned on to inject standard acid into the reaction vessel to drive out air bubbles in the pipeline; then, the fourth delivery pump of the drainage unit is turned on to drain the standard acid injected into the reaction vessel. Through the above operations, the liquid path can be kept unobstructed and the liquid volume can be accurately measured during the titration process, avoiding volume measurement errors caused by air bubble interference, and improving the accuracy and stability of the titration results.

[0046] Furthermore, in this invention, if insoluble impurities are present in the brine, the reaction vessel is pre-washed by the water washing unit controlled by the controller before titration begins. Specifically, water is injected into the reaction vessel by activating the third delivery pump to rinse and remove any adhering impurities, ensuring the cleanliness of the interior of the reaction vessel. This water washing step prevents insoluble impurities from interfering with pH detection and volume determination during titration, thereby improving the accuracy and repeatability of the detection results.

[0047] Before titration begins, this invention prioritizes the injection of saline solution into the reaction vessel to pre-wash it, ensuring that the internal environment matches the actual testing conditions. Specifically, when the saline inlet pipe is long, air or impurities are more likely to remain inside. Pre-washing with saline effectively flushes the pipe and eliminates interference, ensuring that the saline sample entering the reaction vessel subsequently has higher representativeness and accuracy, thereby improving the reliability of the titration results.

[0048] For any experimental steps or conditions not specified in the following examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0049] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0050] Example 1 Combination Figure 1 and Figure 2 As shown, this embodiment provides a method for analyzing the excess alkalinity of brine, specifically including the following steps: S101, Water washing; The third delivery pump 41 of the control water washing unit is turned on to wash the reaction vessel 2 with water, and the fourth delivery pump 51 of the control draining unit is turned on to drain the washing liquid away. S102, Expel air bubbles; The second delivery pump 31 is turned on to inject standard acid into the reaction vessel 2 to drive out air bubbles in the pipeline; then the fourth delivery pump 51 of the drainage unit is turned on to discharge the standard acid injected into the reaction vessel 2. S103, washed with salt water; The controller controls the first delivery pump 11 to turn on, inputting the brine to be tested into the reaction vessel 2 to wash the reaction vessel 2 with brine. After washing with brine, the controller controls the fourth delivery pump 51 of the drainage unit to turn on to discharge the brine injected into the reaction vessel and then turns off the drainage unit. S2, Inject the saline solution to be tested; The controller controls the first delivery pump 11 to turn on, and inputs the saline solution to be tested into the reaction vessel 2, with an injection volume of V; S3, titration; Turn on the stirring device to start stirring at a speed of 800 rpm; The controller controls the second delivery pump 31 at a titration rate U. 初 Titrate to a pH of 10.5, U 初 The titration rate is 8 ml / min. After titration is complete, the second delivery pump is turned off for 30 seconds. Then, control the second delivery pump 31 to titrate at the first titration rate U1 to pH 8.5, where U1 is 3 ml / min. After titration is completed, control the second delivery pump to turn off for 30 seconds. Record the volume V1 of hydrochloric acid consumed in titrating from pH 10.5 to pH 8.5. Then control the second delivery pump 31 to titrate at the third titration rate U3 until the pH value is 6.5, U3 is 5ml / min. After the titration is completed, control the second delivery pump to turn off for 30 seconds. Control the second delivery pump 31 to titrate to pH 4.5 at the second titration rate U2, where U2 is 3 ml / min. After titration is complete, control the second delivery pump 31 to turn off. Record the volume V2 of hydrochloric acid consumed in titrating from pH 8.5 to pH 4.5. The formulas for calculating the concentrations of NaOH and Na2CO3 in the saline solution to be tested are as follows: NaOH = ((V1- V2) ×c× 40) / V + b1; Na2CO3= (2× V2× c× 52.99) / V + b2; Where c is the hydrochloric acid concentration, V is the volume of the saline solution to be tested, and b1 and b2 are the calibration intercepts.

[0051] Comparative Example 1 This comparative example uses existing testing instruments for detection; after quality control analysts take samples, the content of sodium hydroxide and sodium carbonate in the saline solution is determined in the laboratory using acid-base titration. The specific steps are as follows: Accurately transfer 50.00 mL of the salt solution to be tested into a 250 mL Erlenmeyer flask, add 25 mL of pure water to dilute, and shake well; First endpoint determination, phenolphthalein indicator method: Add 2-3 drops of phenolphthalein indicator to the solution. The solution turns pink. Titrate with standard hydrochloric acid solution until the pink color just disappears. Record the volume of hydrochloric acid consumed, V1. Second endpoint determination, methyl orange indicator method: Add 1-2 drops of methyl orange indicator to the above solution. The solution will turn yellow. Continue titrating with standard hydrochloric acid solution until the solution changes from yellow to orange. Record the volume of hydrochloric acid consumed, V2. To verify the accuracy and reliability of the brine excess analysis method provided by this invention in detecting the sodium carbonate and sodium hydroxide content in brine under actual production conditions, ceramic membrane brine samples from different production lines were selected and tested using the artificial acid-base titration analysis method described in Comparative Example 1 and the automatic titration analysis method described in Example 1, respectively. The test results were then compared and analyzed.

[0052] Comparative Example 1 uses conventional laboratory manual acid-base titration, with phenolphthalein and methyl orange indicators as endpoint determination criteria; Example 1 uses the automatic titration analysis method with multiple titration points and segmented variable speed control proposed in this invention, which determines the titration endpoint through online pH monitoring and calculates the content of sodium carbonate and sodium hydroxide in the brine based on the volume of standard acid consumed at each stage.

[0053] By testing the same saline sample using both methods described above, the consistency and accuracy of the analytical method of this invention in determining the content of sodium carbonate and sodium hydroxide can be verified, thereby evaluating the feasibility and engineering applicability of the method of this invention as a substitute for manual analysis. The test results for each sample are shown in Table 1 below.

[0054] Table 1: Comparison of detection results of sodium carbonate and sodium hydroxide content in saline solution using different analytical methods

[0055] As shown in Table 1, for ceramic membrane brine samples from different production lines, the results obtained by using the manual titration analysis method described in Comparative Example 1 and the analytical method of the present invention described in Example 1 to determine the sodium carbonate and sodium hydroxide content in the brine are basically consistent. Specifically, for the sodium carbonate content, the results obtained by the two analytical methods are at the same level for both line A and line B brine samples, with little difference; for the sodium hydroxide content, the detection results of the analytical method of the present invention are also in good consistency with the results of manual analysis, and no obvious deviation was observed.

[0056] The automated titration analysis method with multiple titration points and segmented variable speed control proposed in this invention achieves a detection level comparable to traditional manual titration analysis methods in terms of accuracy in determining the content of sodium carbonate and sodium hydroxide, accurately reflecting the actual changes in the content of superalkaline components in brine. While ensuring the reliability of the detection results, the analytical method of this invention reduces the influence of manual sampling and manual endpoint determination on the detection results, effectively reducing the uncertainty caused by human operation, and providing a stable and reliable data foundation for online, continuous, and automated monitoring of superalkalinity in brine.

[0057] The brine alkalinity analysis method and system provided by this invention enable periodic real-time monitoring of sodium carbonate and sodium hydroxide content in brine, and timely adjustment of the amount of relevant alkaline substances added based on the detection results. Compared with traditional manual detection methods, this invention can significantly shorten the detection cycle, increase the monitoring frequency, and make the control process of alkaline components in brine more precise and stable.

[0058] In actual production operations, sodium carbonate, as an important auxiliary material, typically needs to be controlled within a reasonable range in excess levels in brine. This invention, through continuous and accurate monitoring of the sodium carbonate and sodium hydroxide content, helps avoid excessive addition of auxiliary materials, reducing auxiliary material consumption while ensuring stable production process operation. For large-scale continuous production scenarios, the auxiliary material saving effect brought about by this invention has significant cumulative advantages, generating good economic benefits in long-term operation.

[0059] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for analyzing the alkalinity of brine, characterized in that: include: The brine was titrated using a standard acid titration unit. The amount of excess alkali in the brine was obtained based on the volume of standard acid consumed in titration to the target titration point. The target titration point includes at least a first titration point with a pH of 7.6 to 8.5, a second titration point with a pH of 3.9 to 4.5, and a third titration point between the first and second titration points; The titration rate U3 is controlled to be greater than the titration rate to the first and / or second titration points.

2. The method for analyzing the alkalinity of brine according to claim 1, characterized in that: The target titration point also includes an initial titration point with a pH value of 9.8–10.5, and the titration rate U is controlled to titrate to the initial titration point. 初 A titration rate greater than the titration rate to the first titration point and / or the second titration point; Preferably, the titration rate U is controlled. 初 It is greater than the titration rate U3.

3. A method for analyzing the alkalinity of brine according to claim 1 or 2, characterized in that: Each titration to a target titration point is completed at intervals of a set time t. 间隔 Then, perform the next titration. Preferably, the interval is set to a time t. 间隔 It is 0.32 to 2 times the titration time corresponding to titration to a target titration point.

4. A method for analyzing the alkalinity of brine according to any one of claims 1-3, characterized in that: If air bubbles are present in the storage pipeline of the standard acid titration unit before titration begins, the standard acid titration unit should be controlled to purge the air bubbles before titration.

5. The method for analyzing the alkalinity of brine according to claim 4, characterized in that: The titration includes: injecting saline solution into the reaction vessel, and then controlling the standard acid titration unit to inject standard acid into the reaction vessel for titration; The air venting process includes: before injecting brine into the reaction vessel, controlling the standard acid titration unit to inject standard acid into the reaction vessel, and then venting it out of the reaction vessel.

6. A method for analyzing the alkalinity of brine according to any one of claims 1-5, characterized in that: The reaction vessel used for titration is connected to a water washing unit. If the brine contains insoluble impurities, the water washing unit is controlled to introduce water into the reaction vessel to wash the reaction vessel before starting the titration.

7. A method for analyzing the alkalinity of brine according to any one of claims 1-6, characterized in that: Before starting the titration, the reaction vessel is first rinsed with brine by adding brine to the reaction vessel.

8. A brine superalkalinity analysis system controlled by the analytical method described in any one of claims 1-7, characterized in that: include: A reaction vessel, a standard acid titration unit connected to the reaction vessel, and a brine input unit; The controller is electrically or communicatively connected to the standard acid titration unit and the saline input unit. The controller controls the brine input unit to input the brine to be tested into the reaction vessel, and controls the standard acid titration unit to inject standard acid into the reaction vessel to titrate the brine to be tested. The excess alkali in the brine is obtained based on the volume of standard acid consumed in titration to the target titration point.

9. The brine superalkalinity analysis system according to claim 8, characterized in that: The reaction vessel is connected to a water washing unit, and the water washing unit is connected to the controller; The controller controls the water washing unit to introduce water into the reaction vessel to wash the reaction vessel.

10. The brine superalkalinity analysis system according to claim 8 or 9, characterized in that: The reaction vessel is connected to a draining unit, and the controller is connected to the draining unit to control the draining unit to drain the liquid in the reaction vessel. Preferably, the reaction vessel is equipped with a stirring device.

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