Method and system for detecting electrochemical cell damage using inert gas injection and dynamic differential pressure analysis

Abstract

A damage detection method for an electrolytic cell includes dividing cells of the electrolytic cell into a class having a damaged membrane, performing a first test to confirm whether the class includes at least one cell, the at least one first test based on injecting an inert gas at an anode and a cathode of each cell, when a result of the first test confirms that the class includes the at least one battery, replacing the battery and performing a second test to assess whether there is at least one further damaged battery; when the result of the second test indicates that there is at least one further damaged battery, stopping the electrolytic cell and repeating the following steps: performing the first test, replacing the battery and performing the second test, repeating, and when the result of the second test indicates that there is no further damaged battery, replacing the battery with the battery, and performing the second test. And starting the electrolytic bath.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Patent Application No. 63 / 431,857, filed on December 12, 2022, the entire content of which is incorporated herein by reference. Technical field

[0003] The present disclosure generally relates to industrial electrolytic cells, and more particularly to identifying damaged electrolytic cell membranes prior to initiating a full operating cycle. Background art

[0004] An electrochemical cell (also referred to herein as a "cell") is a device that performs a chemical decomposition reaction by applying an electric current. Such a device is used to decompose salts (NaCl) into caustic soda (NaOH) and chlorine gas (Cl2). It is also used to decompose potassium chloride into potassium hydroxide and chlorine gas. Similar processes such as water electrolysis for hydrogen production are also carried out using electrochemical cells.

[0005] In an industrial environment, multiple cells are connected in series or parallel for reaction. Such a combination is called an electrolytic cell. Most industrial electrochemical cells consist of two electrodes (anode and cathode) and a membrane. In some cases, the membrane can also be referred to as a diaphragm, cell separator, cell membrane, exchange membrane, or ion exchange membrane. When cations are exchanged through the membrane, the membrane can be called a cation exchange membrane. Oxidation occurs at the anode and reduction occurs at the cathode. In modern electrochemical cells, membranes such as ion exchange membranes are used to allow only desired ions to migrate from one side of the reaction (anode) to the other side (cathode). The efficiency and safety of industrial electrochemical cells mainly relate to the safety and efficiency of their components. More specifically, it relates to the safety and efficiency of the cation exchange membrane. Although the cation exchange membrane has efficient and environmentally friendly characteristics, it is very sensitive to contaminants at the inlet exceeding the allowable concentration and mechanical defects during installation or operation. The cation exchange separation efficiency is severely affected by small holes or cracks (also known as pinholes or pores). Some reasons for the appearance of pinholes in the cell membrane include: voids, bubbles, and membrane detachment caused by mechanical stress during maintenance and by contaminated electrolyte mainly during shutdown and startup operating modes. For example, the appearance of pinholes in the membrane affects the efficiency of the cell and the service life of the cell in different ways, depending on the size and location of the pinholes (e.g., in the part of the cell with liquid or in the other part of the cell with only gas). Pinholes may reduce the membrane separation ability, thus preventing the hydroxyl ions from migrating back to the anolyte chamber. Usually, the pinhole effect cannot be detected during normal operation, unless during the chlor-alkali electrolysis process, the anode coating corrodes due to the erosion of caustic soda. However, the pinhole effect is obvious during startup or shutdown because they affect the cell voltage. The decrease in the separation efficiency of the ion exchange membrane may cause the mixing of gases such as H2 and Cl2 or H2 and O2, which may trigger an explosion or result in the leakage of electrolyte that is fatal to humans and harmful to the environment.

[0006] It is well known to detect membrane damage by analyzing the current-voltage curves during the startup and after the shutdown of the electrolytic cell. However, once the membrane is damaged, there is a risk of gas mixing when gas production starts and it may lead to an explosion. There is currently no method to ensure that an explosive mixture of gases from the anode side and the cathode side will not form when the electrolytic cell is powered on. The well-known membrane leak test can only be carried out when the electrolytic cell is emptied or the electrolyte circulation stops.

[0007] Therefore, there is a need to improve the method to detect membrane damage before the electrolytic cell is powered on, that is, before the gases that may form an explosive mixture are produced. Summary of the Invention

[0008] According to a broad aspect, a method for detecting damage to an electrolytic cell having a plurality of electrolytic cells is provided. The method includes: during a shutdown of the electrolytic cell, obtaining one or more first voltage measurements for each of the plurality of cells; based on the one or more first voltage measurements, performing a first classification of the plurality of cells to classify the plurality of cells into a first class of cells having a damaged membrane and a second class of cells without the damaged membrane; performing one or more first tests in the electrolytic cell to confirm whether the first class of cells includes at least one cell, at least one of the one or more first tests being based on injecting an inert gas into an anode and a cathode of each of the plurality of cells; determining that the results of the one or more first tests confirm that the first class of cells includes at least one cell, replacing the at least one cell, and performing a second test in the electrolytic cell to evaluate whether there is at least one additional cell having the damaged membrane in the electrolytic cell; determining that the results of the second test indicate that there is at least one additional cell having the damaged membrane in the electrolytic cell, stopping the electrolytic cell, and repeating the following steps: performing the one or more first tests, replacing at least one cell having the damaged membrane, and performing the second test; and determining that the results of the second test indicate that there are no longer any cells having the damaged membrane in the electrolytic cell, and starting the electrolytic cell.

[0009] In at least one embodiment according to any previous / other embodiment described herein, the method further includes performing the second test when determining that the results of the one or more first tests fail to confirm that the first class of cells includes at least one cell having a damaged membrane.

[0010] In at least one embodiment according to any previous / other embodiment described herein, performing the first classification of the plurality of cells includes determining a cell current efficiency of the electrolytic cell during the shutdown of the electrolytic cell, the cell current efficiency being a function of the time required for the voltage level of each cell of the electrolytic cell to reach a predetermined occurrence point in a voltage curve after a polarization current is triggered in the electrolytic cell.

[0011] In at least one embodiment according to any previous / other embodiment described herein, determining the cell current efficiency includes using a formula having the following form:

[0012] , where is the cell current efficiency of each cell of the electrolytic cell, is the time required for the voltage level of each cell to switch from chlorine electrolysis to water electrolysis, and is a parameterized non - linear function.

[0013] In at least one embodiment of any previous / other embodiment described herein, the method further includes, after performing the first classification on the plurality of cells, triggering an alarm indicating the detection of the first type of cells having the damaged membrane.

[0014] In at least one embodiment of any previous / other embodiment described herein, the method further includes initiating maintenance of the electrolytic cell after performing the first classification on the plurality of cells.

[0015] In at least one embodiment of any previous / other embodiment described herein, the method further includes, after starting the electrolytic cell: during the start-up of the electrolytic cell, obtaining one or more second voltage measurements of each cell of the plurality of cells of the electrolytic cell; based on the one or more second voltage measurements, performing a second classification on the plurality of cells to classify the plurality of cells into a first type of cells having a damaged membrane and a second type of cells not having the damaged membrane; evaluating whether the first type of cells includes at least one cell; determining that the first type of cells includes the at least one cell, stopping the electrolytic cell, and repeating the following steps: replacing the at least one cell and performing a second test of evaluating whether there is at least one additional cell having the damaged membrane in the electrolytic cell; and determining that the first type of cells does not include the at least one cell and continuing the normal operation of the electrolytic cell.

[0016] In at least one embodiment of any previous / other embodiment described herein, performing the second classification on the plurality of cells includes determining the cell current efficiency of the electrolytic cell during the start-up of the electrolytic cell, the cell current efficiency being determined based on a look-up table associating the current efficiency range of each cell of the electrolytic cell with the time required to generate chlorine after triggering a polarization current in each cell in the electrolytic cell.

[0017] In at least one embodiment of any previous / other embodiment described herein, each cell of the electrolytic cell includes at least a cathode, an anode, and a membrane between the cathode and the anode, and performing the second test includes injecting a first inert gas into the cathode of each cell of the electrolytic cell, injecting a second inert gas into the anode of each cell of the electrolytic cell, and comparing the rate of change of the concentration of the inert gas mixture at the anode electrolyte outlet of the electrolytic cell with a concentration change rate threshold, and for a given cell of the electrolytic cell, a rate of change of the concentration of the inert gas mixture greater than the concentration change rate threshold indicates that the membrane of the given cell is damaged, and determining the position of the given cell based on the time required for the rate of change of the concentration of the inert gas mixture to exceed the concentration change rate threshold.

[0018] In at least one embodiment according to any previous / other embodiment described herein, the plurality of cells of the electrolytic cell is one of a plurality of chlor-alkali electrolytic cells and a plurality of non-alkaline water electrolytic cells.

[0019] According to another broad aspect, there is provided a combined device comprising: a plurality of electrolytic cells forming one or more electrolytic cells; and a damage detection system comprising at least one computing device operably connected to the one or more electrolytic cells, the at least one computing device comprising at least one processing unit and a non-transitory computer-readable medium having program instructions stored thereon that are executable by the at least one processing unit for, during a downtime of the electrolytic cell, obtaining one or more first voltage measurements of each of the plurality of cells; based on the one or more first voltage measurements, performing a first classification of the plurality of cells to classify the plurality of cells into a first class of cells having a damaged membrane and a second class of cells not having the damaged membrane; performing one or more first tests in the electrolytic cell to confirm whether the first class of cells includes at least one cell, at least one of the one or more first tests being based on injecting an inert gas into an anode and a cathode of each of the plurality of cells of the electrolytic cell; determining that the result of the one or more first tests confirms that the first class of cells includes at least one cell, replacing the at least one cell, and performing a second test in the electrolytic cell to evaluate whether there is at least one additional cell having the damaged membrane in the electrolytic cell; determining that the result of the second test indicates that there is at least one additional cell having the damaged membrane in the electrolytic cell, stopping the electrolytic cell, and repeating the following steps: performing the one or more first tests, replacing at least one cell having the damaged membrane, and performing the second test; and determining that the result of the second test indicates that there are no longer any cells having the damaged membrane in the electrolytic cell, and starting the electrolytic cell.

[0020] In at least one embodiment according to any previous / other embodiment described herein, the one or more first voltage measurements are obtained from at least one data acquisition and transmission (DAT) module communicatively connected to the plurality of cells, the at least one DAT module being configured to measure the voltages of the plurality of cells.

[0021] In at least one embodiment according to any previous / other embodiment described herein, the instructions can be further executed by the at least one processing unit for performing the second test when it is determined that the result of the one or more first tests does not confirm that the first class of cells includes at least one cell having a damaged membrane.

[0022] In at least one embodiment according to any previous / other embodiment described herein, the instructions are executable by the at least one processing unit for performing the first classification on the plurality of cells, including using a cell classification and damage detection module communicatively coupled to the at least one DAT module to determine the cell current efficiency of the electrolytic cell during the electrolytic cell shutdown, the cell current efficiency being a function of the time required for the voltage level of each cell of the electrolytic cell to reach a predetermined occurrence point in a voltage curve after a polarization current is triggered in the electrolytic cell.

[0023] In at least one embodiment according to any previous / other embodiment described herein, the instructions are executable by the at least one processing unit for determining the cell current efficiency using a formula having the following form:

[0024] , where, is the cell current efficiency of each cell of the electrolytic cell, is the time required for the voltage level of each cell to switch from chlorine electrolysis to water electrolysis, and is a parameterized non - linear function.

[0025] In at least one embodiment according to any previous / other embodiment described herein, the instructions are further executable by the at least one processing unit for, after performing the first classification on the plurality of cells, triggering an alarm indicating the detection of the first type of cells having the damaged membrane and / or initiating maintenance of the electrolytic cell.

[0026] In at least one embodiment according to any previous / other embodiment described herein, the instructions are further executable by the at least one processing unit for, after starting the electrolytic cell: during the start - up of the electrolytic cell, acquiring one or more second voltage measurements of each cell of the plurality of cells of the electrolytic cell; based on the one or more second voltage measurements, performing a second classification on the plurality of cells to classify the plurality of cells into a first type of cells having a damaged membrane and a second type of cells not having the damaged membrane; evaluating whether the first type of cells includes at least one cell; determining that the first type of cells includes the at least one cell, stopping the electrolytic cell, and repeating the following steps: replacing the at least one cell and performing the second test of evaluating whether there is at least one additional cell having the damaged membrane in the electrolytic cell; and determining that the first type of cells does not include the at least one cell and continuing the normal operation of the electrolytic cell.

[0027] In at least one implementation of any prior / other implementation described herein, the instructions can be further executed by the at least one processing unit for performing the second classification on the plurality of cells, including determining a cell current efficiency of the electrolyzer during start-up of the electrolyzer, the cell current efficiency being determined based on a look-up table that correlates a current efficiency range of each cell of the electrolyzer with a time required for each cell to generate chlorine gas after triggering a polarization current in the electrolyzer.

[0028] In at least one implementation of any prior / other implementation described herein, each cell of the electrolyzer includes at least a cathode, an anode, and a membrane between the cathode and the anode, and the instructions can be executed by the at least one processing unit for performing the second test, including injecting a first inert gas into the cathode of each cell of the electrolyzer using an inert gas leak test system connected to the plurality of cells, injecting a second inert gas into the anode of each cell of the electrolyzer, and comparing a rate of change of the concentration of an inert gas mixture at an anode electrolyte outlet of the electrolyzer with a concentration change rate threshold, and for a given cell of the electrolyzer, a rate of change of the concentration of the inert gas mixture greater than the concentration change rate threshold indicates that the membrane of the given cell has been damaged, and determining a position of the given cell based on a time required for the rate of change of the concentration of the inert gas mixture to exceed the concentration change rate threshold.

[0029] In at least one implementation of any prior / other implementation described herein, the plurality of cells is one of a plurality of chlor-alkali electrolysis cells and a plurality of non-alkaline water electrolysis cells.

[0030] Features of the systems, devices, and methods described herein can be used in various combinations according to the implementations described herein. Description of the Drawings

[0031] Figure 1A and Figure 1B is a flow chart of a method for detecting a damaged membrane in an electrochemical cell using inert gas injection;

[0032] Figure 2A is a schematic diagram of a system for performing an inert gas leak test; and

[0033] Figure 2B is from Figure 2A starting with injecting helium gas into a cathode electrolyte outlet header, Figure 2A a graph of the change in helium gas concentration over time at an anode electrolyte outlet header of

[0034] Figure 3 is a schematic diagram of an electrolytic cell voltage measurement and classification system;

[0035] Figure 4 is a method for implementing Figure 1A and Figure 1B and / or a block diagram of an example computing system of a system for Figure 3 ;

[0036] Figure 5A , Figure 5B , Figure 5C and Figure 5D are graphs of cell voltage and current during electrolyzer startup and shutdown.

[0037] Note that in the drawings, like features are identified by like reference numerals. DETAILED DESCRIPTION

[0038] Four methods are generally used to detect damaged membranes to avoid H2 / Cl2 - or H2 / O2 - explosions or electrolytic cell leaks. As used herein, the term "damaged" (or "damage") when used in reference to a membrane of an electrochemical cell, such as a cation exchange membrane, refers to a membrane having a severe defect or malfunction. As used herein, a damaged membrane can be defined as a membrane containing pinholes that reduce the membrane's separation ability. Due to the backmigration of hydroxyl ions to the cell anolyte chamber, product loss occurs. In addition, hydrogen gas can enter the anode chamber and form an explosive mixture with chlorine gas.

[0039] In the first method, a pressure differential is applied across the membrane using nitrogen gas (N2). All valves are closed. A rapid drop in the pressure differential indicates membrane damage. However, this test does not determine which membrane in all the operating cells needs to be replaced and this method is also difficult to automate. This test also interrupts and delays the normal startup procedure. All operations such as the flow or heating of the electrolyte should be stopped. Since the electrolyzer is not empty, only large - area membrane damage at the top of the membrane can be detected. During operation, the liquid level on the cathode side of the electrolyzer drops by more than 10%. Therefore, holes that are not detected by this test may pose a safety hazard during operation.

[0040] In the second method, nitrogen gas (N2) is applied to the cathode electrolyte side of an empty electrolyzer. All valves are closed. If a rapid drop in the pressure differential indicates membrane damage, gas exchange between the anode - side cells is prohibited by flooding the inlet or outlet headers, while a device is connected separately at other cell connections to measure the flow rate or pressure of the leaked gas, etc. Since the automation cost of all relevant manual valves is high, this test is performed manually. In addition, this method delays the startup time by several hours and the corresponding production loss is significant. In particular, if multiple membranes have small non - critical damages, the initial analysis of the pressure - differential drop of the entire electrolyzer often results in false - positive detections.

[0041] In the third method, the electrolyzer is started with a large nitrogen feed to dilute the hydrogen produced so that it does not exceed the explosion limit when mixed with the gas from the anode. At the anode electrolyte outlet header, the hydrogen concentration is analyzed. This test is usually carried out automatically. However, this test cannot determine which cells have damaged membranes and need to be replaced. The remaining risk of explosion depends on the response time of the analyzer. Since the electrolyzer is not empty, only large-area membrane damage at the top of the membrane can be detected. During operation, the liquid level on the cathode side in the electrolyzer drops by more than 10% between low-load and high-load operation. Therefore, holes not detected by this test may become a safety hazard during operation.

[0042] In the fourth method, compared with cells without damaged membranes, after shutdown, the voltage of cells with damaged membranes drops faster, and during startup, the voltage of cells with damaged membranes rises later. This method is highly sensitive and can accurately classify the performance of each membrane, so as to take appropriate countermeasures. This test can be easily automated. However, this requires stopping or starting the electrolyzer and cannot completely avoid the risk of starting an electrolyzer with a damaged membrane after shutdown. Only by applying sufficient nitrogen to dilute the hydrogen can the startup of a damaged membrane be safe. The safe flow rate of nitrogen cannot be predicted because it depends on the number of damaged membranes and the severity of each membrane damage.

[0043] Chlor-alkali plants can combine different methods according to the assumed risk of damaged membranes. For example, if there is no abnormal pressure or pressure difference when the electrolyzer is shut down and the fourth method above does not give an alarm during shutdown, the electrolyzer can be started using only the fourth method. On the other hand, if the shutdown control of the electrolyzer is not ideal (e.g., due to insufficient pressure control, etc.), the first method above can be adopted, and if the first method fails, the second method can be adopted; otherwise, the fourth method is used to start the electrolyzer.

[0044] Described herein are methods and systems for detecting defects (i.e., damage) in ion exchange membranes operating in industrial-scale electrolyzers such as chlor-alkali electrolyzers. It should be understood that the methods and systems described herein can also be used to detect damage in battery diaphragms. The proposed method is based on inert leak gas analysis, preferably helium (He). In one embodiment, the method can be used during the start-up, filling, or preparation for the heating operation mode of the electrolyzer. Helium can be supplied to the cathode side via a nitrogen purge line and analyzed at the anolyte outlet header of the electrolyzer. If the helium concentration is higher than a given (predetermined) concentration threshold, the systems and methods described herein will automatically prevent the start-up of the electrolyzer. In this way, it is possible to ensure an accurate determination of the maximum expected peak concentration of hydrogen in the anode header of the electrolyzer at start-up. Monitoring the leakage rate of the He / N2 mixture from the cathode to the anode side during the filling of the electrolyzer can also predict the expected peak concentration during the period from start-up to full-load operation.

[0045] In one embodiment, the proposed method can prevent the operation of an industrial electrolyzer with a defective membrane before gas production begins. This is in contrast to existing leak test methods that can only be performed when the electrolyzer is emptied or the electrolyte circulation is stopped.

[0046] Figure 1A and Figure 1B FIG. shows a method 100 for detecting a damaged membrane in an operating electrolyzer according to one embodiment. In step 102, during a load reduction (i.e., during electrolyzer shutdown), voltage measurements (referred to herein as "first voltage measurements") of each operating cell of the electrolyzer are obtained in real time or pseudo-real time. Voltage measurements can be obtained using one or more data acquisition devices such as one or more data acquisition and transmission (DAT) modules 301, which will be further described below with reference to Figure 3 Therein. The data acquisition device can also sense the main electrolyzer current and obtain process measurements such as, but not limited to, the electrolyzer brine inlet pH value and the electrolyzer feed brine flow rate [m 3 / h]. In step 104, the data obtained in step 102 is analyzed to classify and detect operating cells with damaged membranes. In step 104, a first classification of dividing a plurality of cells into a first class of cells with damaged membranes and a second class of cells without damaged membranes is performed based on one or more first voltage measurements. Step 104 can be performed using a computer device such as a cell classification and damage detection module 303, which will be further described below with reference to Figure 3 Therein. Further below will also be referred to Figure 5A and Figure 5BFurther described, in one embodiment, the step 104 of classifying and detecting a damaged membrane (during the electrolyzer shutdown operation mode) can be based on an approximation of the individual cell current efficiency of the electrolyzer using the duration required to reach a minimum voltage threshold.

[0047] In step 106, an indication of the presence of a damaged membrane can be output. For example, if a damaged membrane is detected in step 104, an alarm indicating the detection of a damaged membrane may be triggered. Maintenance of the electrolyzer can be initiated in step 108. Step 108 may involve any appropriate actions performed to initiate maintenance, including but not limited to inventory consultation, operator shift scheduling, and equipment preparation or calibration, etc.

[0048] In step 110, one or more first tests (referred to herein as confirmation tests) are performed in the electrolyzer to verify the result of step 104. Although step 110 is shown as being performed after steps 106 and 108, it should be understood that in some embodiments, step 110 can be performed immediately after step 104. According to one embodiment, a helium leak test is performed in step 110 to confirm the presence of a damaged membrane determined in step 104. In one embodiment, at least one first (or confirmation) test is based on injecting an inert gas into the anode and cathode of each cell of the electrolyzer. In other alternative embodiments, the above-described second and / or third detection methods can be performed as confirmation tests in step 110. Once the confirmation test is completed, an evaluation is made in step 110 to determine whether the confirmation test confirms the presence of a damaged membrane. If at least one test performed in step 110 confirms the presence of at least one damaged membrane, the next step 112 can be to replace the damaged membrane. Step 112 may include performing disassembly / assembly activities to replace at least one damaged membrane.

[0049] In step 114, a second test (referred to herein as an inert gas (such as helium) leak test) is performed in the electrolyzer to detect whether there are any damaged membranes. In some embodiments, step 114 can be performed after the replacement activities of step 112. These replacement activities may cause membrane damage, for example, due to mechanical tension, torsion, etc. In other embodiments, step 114 can be performed after it is determined in step 110 that the confirmation test fails to confirm the presence of a damaged membrane and no replacement activities are performed in step 112, to confirm the result of the confirmation test performed in step 110. In some embodiments, the confirmation test in step 110 may fail to confirm the presence of a damaged membrane due to a false negative, for example, due to improper handling or incorrect operation of the electrolyzer or its components. In such a case, it may be necessary to perform an inert gas test in step 114 as a redundant step.

[0050] Subsequent evaluation is then performed in step 116 to re-evaluate whether one or more damaged membranes are detected after step 114 (i.e., based on the results of the inert gas test). If at least one damaged membrane is confirmed in step 116, the operation of the electrolytic cell is stopped in step 118 and steps 110 to 116 may then be repeated until no more damaged membranes are detected. In some embodiments, step 118 may include stopping the operation of the electrolytic cell by interrupting the electrolytic cell startup sequence or blocking the electrolytic cell startup instruction, such as the electrolytic cell startup of step 120. Otherwise, if no damaged membranes are detected in step 116, the next step 120 is to start the electrolytic cell, such as by turning on the electrolytic cell power supply.

[0051] In step 122, during a load increase (i.e., during the main current rectifier ramp-up that occurs during electrolytic cell startup), voltage measurements (referred to herein as "second voltage measurements") are acquired in real time or pseudo-real time at each operating cell of the electrolytic cell. The voltage measurements can be acquired using one or more of the data acquisition devices described above with reference to step 102 (e.g., the DAT module 301). In step 124, the data acquired in step 122 (i.e., the voltage measurements) is analyzed to classify and detect operating cells with damaged membranes. Specifically, in step 124, a second classification is performed based on one or more second voltage measurements acquired in step 122 to divide the plurality of cells into a first class of cells with damaged membranes and a second class of cells without damaged membranes. Further details will be described below with reference to Figure 5C and Figure 5D In one embodiment, the step 124 of classifying and detecting damaged membranes (during the electrolytic cell startup operating mode) is based on an approximation of the individual cell current efficiency of the electrolytic cell using a theoretical look-up table in which each current efficiency range is associated with the time at which each cell begins to produce chlorine based on the feed current. Step 124 can be performed using any suitable computing device, such as the cell classification and damage detection module 303 described above with reference to step 104.

[0052] Then, method 100 can evaluate in step 126 whether a damaged membrane is detected. If this is the case and one or more damaged membranes are detected in step 126, an alarm is triggered similar to step 106 above. Then the electrolytic cell is stopped in step 128 and steps 112 to 126 are repeated until no more damaged membranes are detected. When it is determined in step 126 that no damaged membranes are detected, the next step 130 proceeds with normal electrolytic cell operation.

[0053] Now referring to Figure 2A , a helium leak test for performing, such as Figure 1AAn embodiment of system 200 of step 110 and / or step 114). As described above, system 200 can be used to perform a helium leak test to confirm the presence of a damaged membrane in a chlor-alkali electrolytic cell, such as chlor-alkali electrolytic cell 201. One or more components of system 200 can be controlled (e.g., using any suitable computing device, not shown) to perform the helium leak test. For example, injection of an inert gas into cell 201 can be controlled by a computing device (e.g., a computer-implemented controller).

[0054] In the illustrated embodiment, cell 201 includes a catholyte chamber 202, an anolyte chamber 204, and a membrane 206 separating catholyte chamber 202 from anolyte chamber 204. Cell 201 can be provided with a catholyte inlet 208 and an anolyte inlet 210 for injecting an inert gas into catholyte chamber 202 and anolyte chamber 204, respectively. The inert gas can be injected when cell 201 is emptied of all electrolytes, such as during operating modes including but not limited to electrolytic cell startup, filling, or heating. Catholyte inlet 208 can be disposed at a first location in catholyte chamber 202, and anolyte inlet 210 can be disposed at a second location different from the first location in anolyte chamber 204.

[0055] Cell 201 can further be provided with a catholyte outlet header 212 and an anolyte outlet header 214 for injecting an inert gas into catholyte chamber 202 and anolyte chamber 204, respectively, and / or for analyzing the concentration of the inert gas therein. Catholyte outlet header 212 can be disposed at a third location in catholyte chamber 202 different from the first and second locations, while anolyte outlet header 214 can be disposed at a fourth location in anolyte chamber 204 different from the first, second, and third locations. In other words, the inert gas can be injected into the respective chambers 202 and 204 either via inlets 208 and 210 or, in some cases, via outlet headers 212 and 214. In particular, in one embodiment, when there is no liquid in the electrolytic cell, the inert gas can be injected into cell 201 via inlets 208 and 210; when there is liquid in the electrolytic cell, the inert gas can be injected into cell 201 via outlet headers 212 and 214.

[0056] A test module 216 can be provided for analyzing the concentration of the inert gas mixture in the cell 201. The test module 216 can be communicatively connected to any part of the cell 210 via a communication link 218, such as to the anolyte outlet header 214. For example, the test module 216 can include means for analyzing the concentration of the inert gas mixture. The test module 216 can be provided with at least one sensor (not shown) for measuring the concentration of the inert gas. In some embodiments, the communication link 218 can include at least one communication cable, such as at least one coaxial cable, twisted pair cable, or fiber optic cable, etc. The test module 216 can include any suitable computing device and / or be controlled via any suitable computing device.

[0057] In Figure 2A In one embodiment shown, the catholyte inlet 208 can be used to inject a first inert gas 2201 into the catholyte chamber 202, while the anolyte inlet 210 can be used to inject a second inert gas 2202 different from the first inert gas 2201 into the anolyte chamber 204. In one embodiment, the second gas 2202 can be injected simultaneously with the first gas 2201. In one embodiment, the first gas 2201 is helium and the second gas 2202 is nitrogen. The nitrogen 2202 stream will mix and disperse the leaking helium 222, causing it to pass through the membrane 206 to the anolyte outlet header 214, where the concentration of the helium / nitrogen mixture is analyzed by the test module 216. According to one embodiment, if the helium concentration is higher than a predetermined or pre-determined limit, also referred to herein as the "concentration threshold" (e.g., 0.01% v / v), then it is evaluated that the membrane 206 has been damaged and should be replaced. In an alternative embodiment for testing a non-chlor-alkali electrolysis cell, different preset limits for the helium concentration can be used. In some embodiments, if the system 200 is used to test a non-chlor-alkali electrolysis cell, including but not limited to a hydrochloric acid electrolysis cell, a non-alkaline water electrolysis cell, or a fuel cell, other inert gases, such as CO2, can be injected. Thus, although the cell 201 is referred to herein as a chlor-alkali electrolysis cell, it should be understood that non-chlor-alkali electrolysis cells are equally applicable.

[0058] According to another embodiment, when there is electrolyte (not shown) in the cathode electrolyte chamber 202 and the anode electrolyte chamber 204 of the battery 201 (i.e., the battery 201 is at least partially filled with electrolyte), the battery 201 can be divided into an electrolyte-filled portion 224 and an empty portion 226 (i.e., the portion of the battery 201 without any electrolyte). Due to the presence of electrolyte in the electrolytic cell, helium 228 can be injected into the empty portion 226 of the cathode electrolyte chamber 202 via the cathode electrolyte outlet header 212 instead of via the cathode electrolyte inlet 208, and nitrogen 230 can be injected into the empty portion 226 of the anode electrolyte chamber 204 via the anode electrolyte outlet header 214 instead of via the anode electrolyte inlet 210 to mix and disperse the helium leaking through the battery membrane 206. Therefore, when the concentration of the inert gas in the gas mixture at the anode electrolyte outlet header 214 is higher than a predetermined limit value, membrane damage in the empty portion 226 of the battery 201 can be detected (e.g., using the test module 216).

[0059] When the anode electrolyte chamber 204 and the cathode electrolyte chamber 202 of the battery 201 are filled, the location of membrane damage can be determined by continuously monitoring the helium concentration at the anode electrolyte outlet header 214. When the current of the battery increases and the foam zone at the top of the battery also increases, the way in which the hydrogen concentration in the chlorine gas during operation will increase as the liquid level in the battery decreases can also be calculated.

[0060] According to a preferred embodiment, the inert gas test is carried out in a combined device of multiple electrolytic cells, where the flow rate of the first inert gas 2201 is lower than the flow rate of the second inert gas 2202. The time required for the concentration change rate of the inert gas mixture to exceed a predetermined limit value (i.e., the concentration change rate threshold) determines which electrolytic component in the combined device is severely damaged.

[0061] Figure 2B Figure 240 showing the change of the helium concentration at the anode electrolyte outlet header 214 over time starting from the injection of helium 228 at the cathode electrolyte outlet header 212 provided at the cathode electrolyte chamber 202 is shown. As can be seen from Figure 240, there may be multiple step changes (such as 242 and 244) in the increase of the helium concentration. In one embodiment, the test module 216 can be configured to trigger an alarm indicating a detected damaged membrane if a step change greater than 0.01% v / v is detected. If no step change is detected (i.e., the helium concentration increases continuously), the test module 216 determines that there is no severely damaged membrane in the electrolytic cell. In the example shown in Figure 240, when step changes 242 and 244 both higher than the limit value of 0.01% v / v are detected, an alarm is triggered. Then the location of the damaged battery can be determined based on the time required for the concentration change rate of the inert gas mixture to reach a predetermined limit value (e.g., using the test module 216). Continuing to refer to Figure 2BIn the example shown, the faster the time for the inert gas mixture to reach the step change 242, the closer the damaged component is to the test module 216. The longer the time for the mixture to reach the step change 244, the farther the damaged component is from the test module 216. Other embodiments are also applicable.

[0062] Now referring to Figure 3 , an embodiment of the electrolytic cell voltage measurement and classification system 300 will be described. The system 300 can be used to perform steps 102, 104, 122, and 124 of the method 100 described above with reference to Figure 1A and Figure 1B . The system 300 includes a DAT module 301 for measuring the differential cell voltage of the electrolytic cell 304. The DAT module 301 is configured to measure the cathode-to-cathode or anode-to-anode differential cell voltage in the electrolytic cell 304 with a given accuracy (e.g., + / - 1 millivolt or any other suitable accuracy level). In one embodiment, the electrolytic cell 304 can include an industrial chlor-alkali electrolytic cell having a plurality of cells (not shown). In one embodiment, the cells can be arranged in series configuration, parallel configuration, or a combination thereof. In some embodiments, the electrolytic cell 304 includes up to 160 cells. Other embodiments are also applicable. The protected metal wire 305 can be used to connect the input terminal of each DAT module 301 to the cathode or anode terminal of adjacent cells in the electrolytic cell 304. In some embodiments, each DAT module 301 can measure up to 32 voltage inputs associated with a given cell of the electrolytic cell 304. The DAT module 301 can respectively include a plurality of components, such as an analog-to-digital converter, a digital filter, a memory buffer, and / or a microcontroller to perform data acquisition and transmission routines, etc.

[0063] The data measured by the DAT module 301 can be transmitted to the data processing and communication module 302 using the transmission link 306, and this module obtains the voltage measurements collected by the DAT module 301 according to Figure 1A and Figure 1B steps 102 and 122. For illustration, Figure 3The transmission link 306 therein is shown as a wired connection between the DAT module 301 and the data processing and communication module 302. However, it should be understood that the communication between the DAT module 301 and the data processing and communication module 302 can be achieved through wired, wireless, or a combination of wired and wireless networks. In one embodiment, the wireless network may include a personal area network (PAN), a local area network (LAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a wide area network (WAN), or a combination thereof. The transmission link 306 may include any number of network devices communicating with the DAT module 301 and the data processing and communication module 302 at any location along the network, such as routers, modems, gateways, bridges, hubs, switches, and / or repeaters, etc. In some embodiments, the transmission link 306 can be implemented using wireless broadcast, where at least one transmitter, such as at least one DAT module 301, can send data to at least one receiver (such as the data processing and communication module 302) via at least one antenna provided with at least one transmitter and / or at least one receiver. In other embodiments, the transmission link 306 may include at least one communication cable, such as a coaxial cable, a twisted pair cable, or an optical fiber cable, etc.

[0064] The data processing and communication module 302 can process the data received from the DAT module 301 and transmit the data to the battery sorting and damage detection module 303. In some embodiments, the data processing and communication module 302 may be communicatively connected to the circuit breaker relay 308, such as the circuit breaker relay 308 of an electrolysis plant where the electrolytic cell 304 is operating. The data processing and communication module 302 can execute and send an emergency stop signal 307 to the circuit breaker relay 308. The circuit breaker relay 308 may be communicatively connected to a plant monitoring and data acquisition (SCADA) system (not shown). When activated, the circuit breaker relay 308 can be used to initiate the shutdown of the electrolytic cell 304. In some embodiments, the battery sorting and damage detection module 303 may be located away from the electrolytic cell 304, the DAT module 301, the data processing and communication module 302, and / or the circuit breaker relay 308. In some embodiments, the battery sorting and damage detection module 303 may include a cloud server. Additionally, it should be understood that although shown as separate components in the figure, the data processing and communication module 302 and the battery sorting and damage detection module 303 can be combined or integrated into one component.

[0065] The data processing and communication module 302 can receive, for example, the transformer rectifier shunt current measurement values from the DAT module 301 using a 4 - 20 mA converter terminal (not shown) provided on the data processing and communication module 302. The data processing and communication module 302 can broadcast a data stream of voltage and current sampled at a given rate (e.g., one point per second) to the battery classification and damage detection module 303. In some embodiments, the battery classification and damage detection module 303 can receive electrolysis process measurement data including, but not limited to, electrolyte outlet temperature, caustic soda outlet concentration, and inlet and / or outlet pH values, from a third - party module 310 (such as a computer server) (sometimes referred to as a distributed control system or DCS). According to one embodiment, the battery classification and damage detection module 303 can be configured to classify electrolytic cells and detect damaged membranes from voltage measurements (and optionally, data received from the third - party module 310), as Figure 1A and Figure 1B shown in steps 104 and 124 of

[0066] Referring Figure 4 , a schematic diagram of an example computing device 400 is shown. The computing device 400 can be used to implement the method 100 described above with reference to Figure 1A and Figure 1B and / or one or more elements of the system 300 described above with reference to Figure 3 , including some or all of the data processing and communication module 302 and / or some or all of the battery classification and damage detection module 303. As shown, the computing device 400 includes at least one processor 402, a memory 404 storing instructions 406, and at least one input / output (I / O) interface (shown as “input” and “output” in the figure). For simplicity, only one computing device 400 is shown in the figure, but the system can include more computing devices 400 that can be operated by a user to access remote network resources and exchange data. The computing devices 400 can be of the same or different types. The elements of the computing device 400 can be connected in various ways including direct connection, indirect connection via a network, distributed over a wide geographical area and connected via a network (which can be referred to as “cloud computing”).

[0067] For example, each processor 402 can be any type of general - purpose microprocessor or microcontroller, digital signal processing (DSP) processor, integrated circuit, field - programmable gate array (FPGA), reconfigurable processor, programmable read - only memory (PROM), or any combination thereof.

[0068] For example, the memory 404 may include a suitable combination of any type of computer memory, such as random access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferroelectric RAM (FRAM), etc., located either internally or externally.

[0069] The I / O interface enables the computing device 400 to interconnect with one or more input devices such as a keyboard, mouse, camera, touch screen, and microphone or one or more output devices such as a display screen and speakers.

[0070] In some embodiments, the computing device 400 includes one or more network interfaces to enable the computing device 400 to communicate with other components, thereby exchanging data with other components, accessing and connecting to network resources, providing services for applications, and performing other computing applications by connecting to a network (or networks) capable of transmitting data, including the Internet, Ethernet, plain old telephone service (POTS) lines, public switched telephone network (PSTN), integrated services digital network (ISDN), digital subscriber line (DSL), coaxial cable, fiber optic, satellite, mobile, wireless (e.g., Wi-Fi, WiMAX), SS7 signaling network, fixed line, local area network, wide area network, and other networks, as well as any combination of these networks.

[0071] Now referring to Figure 5A 、 Figure 5B 、 Figure 5C and Figure 5D , the cell voltage and current curves of an electrolytic cell according to one embodiment are described. The cell voltage and current curves during electrolytic cell shutdown when the membrane fails are shown ( Figure 5A and Figure 5B ), and the cell voltage and current curves during electrolytic cell startup when the membrane fails are shown ( Figure 5C and 5D ).

[0072] From Figure 5A and Figure 5B , it can be seen that when the rectified current 502 of the electrolytic cell drops from the normal operating load ( Figure 5A labeled I in 正常) ) to zero (0) kiloamperes, the electrolytic cell shuts down. Compared with an undamaged membrane where the voltage (as shown by curves 504', 504'') may remain at a level greater than the water electrolysis threshold during polarization (after the main current rectifier is cut off), the voltage of a chlor-alkali electrolytic cell with a damaged membrane may drop rapidly (as shown in Figure 5Bas shown by curve 504 in). According to one embodiment, during the electrolyzer shutdown operation mode (as described above), the systems and methods described herein (e.g., Figure 1A in step 104), the monitored cells are divided into cells with damaged membranes and cells without damaged membranes. According to one embodiment of chlor-alkali electrolysis, the classification of the severity of membrane failure is based on the automatic calculation of the current efficiency of each membrane during shutdown. The formula for performing this calculation has the following form:

[0073] (1)

[0074] where:

[0075] The membrane current efficiency of each cell that makes up the electrolyzer;

[0076] The time 506 required for the cell voltage to switch from chlor-alkali electrolysis to water electrolysis ( Figure 5B of), e.g., at 1.9 volts;

[0077] A parametric non-linear function defined using numerical simulation or laboratory data before deployment at the production site, according to the design or technology of the electrolyzer.

[0078] According to one embodiment, by using formula (1) to calculate the current efficiency of each cell of the electrolyzer during shutdown, the membrane status classification can be automatically performed in step 104 of method 100 as described above with reference to Figure 1A and Figure 1B .

[0079] Figure 5C and Figure 5D show the single cell voltage and current curves during membrane failure during electrolyzer startup. As Figure 5C shown, when the electrolyzer is energized with a rectifier current load (as Figure 5C shown by curve 508 in), it enters the electrolyzer startup operation mode, at which time the current increases from zero kiloamperes to the normal operating range. Compared with non-faulty cell membranes where the voltage (as Figure 5D shown by curve 510' in) may reach the equilibrium level faster, the single voltage of a chlor-alkali electrolysis cell with a damaged membrane (as Figure 5D shown by curve 510 in) takes a longer time 512 to reach the voltage equilibrium level of chlor-alkali electrolysis ( Figure 5D labeled V in 平衡) (e.g., 2.2 volts). According to one embodiment of the chlor-alkali electrolysis, the automatic classification of the severity of membrane failure (e.g., performed in step 124) can be based on the automatic approximation of the current efficiency of each membrane during startup. In one embodiment, the individual cell current efficiency of each membrane can be determined through a theoretical look-up table in which, for each current efficiency range, a corresponding time is provided, i.e., the time when each cell starts to produce chlorine gas according to the feed current. The table is established based on the theoretical approximation of the chlorine gas produced over time during the startup of the electrolyzer according to the cell design and technology. In Figure 1B step 122, the current efficiency of each cell is determined using the time correspondence between energizing the electrolyzer with rectified current and reaching the chlorine electrolysis equilibrium voltage level (e.g., 2.2 volts). Cells with a current efficiency below a predetermined threshold can be evaluated as operating with a damaged membrane.

[0080] Various aspects of the methods and systems described herein can be used alone, in combination, or in various arrangements not specifically disclosed in the above embodiments, and thus their application is not limited to the component details and arrangements shown in the above description or the drawings. For example, certain aspects in one embodiment can be combined with certain aspects described in other embodiments in any way. Although specific embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications can be made without departing from the broader aspects of the invention. The scope of the appended claims should not be limited to the embodiments in the examples, but should be given the broadest reasonable interpretation consistent with the entire description.

Claims

1. A method for detecting damage to an electrolytic cell having a plurality of electrolytic cells, the method comprising: During a shutdown of the electrolytic cell, obtaining one or more first voltage measurements for each of the plurality of cells; Based on the one or more first voltage measurements, performing a first classification of the plurality of cells to classify the plurality of cells into a first type of cell having a damaged membrane and a second type of cell without the damaged membrane; Performing one or more first tests in the electrolytic cell to confirm whether the first type of cell includes at least one cell, at least one of the one or more first tests being based on injecting an inert gas into an anode and a cathode of each of the plurality of cells in the electrolytic cell; Determining that the results of the one or more first tests confirm that the first type of cell includes at least one cell, replacing the at least one cell, and performing a second test in the electrolytic cell to evaluate whether there is at least one additional cell having the damaged membrane in the electrolytic cell; Determining that the results of the second test indicate that there is at least one additional cell having the damaged membrane in the electrolytic cell, stopping the electrolytic cell, and repeating the following steps: performing the one or more first tests, replacing at least one cell having the damaged membrane, and performing the second test; And Determining that the results of the second test indicate that there are no longer any cells having the damaged membrane in the electrolytic cell, and starting the electrolytic cell.

2. The method according to claim 1, further comprising performing the second test when determining that the results of the one or more first tests fail to confirm that the first type of cell includes at least one cell having a damaged membrane.

3. The method according to claim 1 or claim 2, wherein performing the first classification of the plurality of cells includes determining a cell current efficiency of the electrolytic cell during the shutdown of the electrolytic cell, the cell current efficiency being a function of the time required for the voltage level of each cell of the electrolytic cell to reach a predetermined occurrence point in a voltage curve after a polarization current is triggered in the electrolytic cell.

4. The method according to claim 3, wherein determining the cell current efficiency includes using a formula having the following form: , wherein, is the cell current efficiency of each cell of the electrolyzer, is the time required for the voltage level of each cell to switch from chlorine electrolysis to water electrolysis, and is a parameterized non-linear function.

5. The method according to any one of claims 1 to 4, further comprising, after performing the first classification of the plurality of cells, triggering an alarm indicating that a first type of cell having the damaged membrane has been detected.

6. The method according to any one of claims 1 to 5, further comprising starting maintenance of the electrolytic cell after performing the first classification of the plurality of cells.

7. The method according to any one of claims 1 to 6, further comprising, after starting the electrolytic cell: During a startup of the electrolytic cell, obtaining one or more second voltage measurements for each of the plurality of cells in the electrolytic cell; Based on the one or more second voltage measurements, performing a second classification of the plurality of cells to classify the plurality of cells into a first type of cell having a damaged membrane and a second type of cell without the damaged membrane; Evaluate whether the first type of battery includes at least one battery; Determine that the first type of battery includes the at least one battery, stop the electrolytic cell, and repeat the following steps: replace the at least one battery and perform a second test of evaluating whether there is at least one additional battery with the damaged membrane in the electrolytic cell; and Determine that the first type of battery does not include the at least one battery, and continue the normal operation of the electrolytic cell.

8. The method according to claim 7, wherein performing the second classification on the plurality of batteries includes determining a cell current efficiency of the electrolytic cell during startup of the electrolytic cell, the cell current efficiency being determined based on a look-up table associating a current efficiency range of each cell of the electrolytic cell with a time required to generate chlorine gas after each cell triggers a polarization current in the electrolytic cell.

9. The method according to any one of claims 1 to 8, wherein each cell of the electrolytic cell comprises at least a cathode, an anode, and a membrane between the cathode and the anode, and performing the second test comprises injecting a first inert gas into the cathode of each cell of the electrolytic cell, injecting a second inert gas into the anode of each cell of the electrolytic cell, and comparing a rate of change in the concentration of an inert gas mixture at the anolyte outlet of the electrolytic cell with a threshold rate of change in concentration, and further wherein, For a given cell of the electrolytic cell, a rate of change of the concentration of the inert gas mixture greater than the concentration change rate threshold indicates that the membrane of the given cell is damaged, and further wherein the position of the given cell is determined based on a time required for the rate of change of the concentration of the inert gas mixture to exceed the concentration change rate threshold.

10. The method according to any one of claims 1 to 9, wherein the plurality of cells of the electrolytic cell is one of a plurality of chlor-alkali electrolytic cells and a plurality of non-alkaline water electrolytic cells.

11. A combined device, comprising: A plurality of electrolytic cells forming one or more electrolytic cells; And A damage detection system, which includes at least one computing device operably connected to the one or more electrolytic cells, the at least one computing device including at least one processing unit and a non-transitory computer-readable medium, and program instructions executed by the at least one processing unit are stored on the non-transitory computer-readable medium for During the shutdown of the electrolytic cell, obtaining one or more first voltage measurements of each cell in the plurality of cells; Based on the one or more first voltage measurements, performing a first classification on the plurality of cells to classify the plurality of cells into a first type of battery with a damaged membrane and a second type of battery without the damaged membrane; Performing one or more first tests in the electrolytic cell to confirm whether the first type of battery includes at least one battery, at least one of the one or more first tests being based on injecting an inert gas into an anode and a cathode of each cell in the plurality of cells of the electrolytic cell; Determine that the result of the one or more first tests confirms that the first type of battery includes at least one battery, replace the at least one battery, and perform a second test in the electrolytic cell to evaluate whether there is at least one additional battery with the damaged membrane in the electrolytic cell; Determine that the result of the second test indicates that there is at least one additional battery with the damaged membrane in the electrolytic cell, stop the electrolytic cell, and repeat the following steps: perform the one or more first tests, replace at least one battery with the damaged membrane, and perform the second test; And Determine that the result of the second test indicates that there are no more cells with the damaged membrane in the electrolytic cell, and start the electrolytic cell.

12. The combined device according to claim 11, wherein the one or more first voltage measurements are obtained from at least one data acquisition and transmission (DAT) module communicatively connected to the plurality of cells, the at least one DAT module being configured to measure the voltages of the plurality of cells.

13. The combined device according to claim 11 or 12, wherein the instructions can be further executed by the at least one processing unit for performing the second test when it is determined that the result of the one or more first tests fails to confirm that the first type of cells includes at least one cell with a damaged membrane.

14. The combined device according to claim 12 or 13, wherein the instructions can be executed by the at least one processing unit for performing the first classification of the plurality of cells, including using a cell classification and damage detection module communicatively connected to the at least one DAT module to determine the cell current efficiency of the electrolytic cell during the electrolytic cell shutdown, the cell current efficiency being a function of the time required for the voltage level of each cell of the electrolytic cell to reach a predetermined occurrence point in the voltage curve after a polarization current is triggered in the electrolytic cell.

15. The combined device according to claim 14, wherein the instructions can be executed by the at least one processing unit for determining the cell current efficiency using a formula having the following form: , wherein, is the cell current efficiency of each cell of the electrolyzer, is the time required for the voltage level of each cell to switch from chlorine electrolysis to water electrolysis, and is a parameterized non-linear function.

16. The combined device according to any one of claims 11 to 15, wherein the instructions can be further executed by the at least one processing unit for, after performing the first classification of the plurality of cells, triggering an alarm indicating that the first type of cells with the damaged membrane has been detected and / or initiating maintenance of the electrolytic cell.

17. The combined device according to any one of claims 11 to 16, wherein the instructions can be further executed by the at least one processing unit for, after starting the electrolytic cell: During the start-up of the electrolytic cell, obtain one or more second voltage measurements of each cell of the plurality of cells of the electrolytic cell; Based on the one or more second voltage measurements, perform a second classification of the plurality of cells to classify the plurality of cells into a first type of cells with a damaged membrane and a second type of cells without the damaged membrane; Evaluate whether the first type of cells includes at least one cell; Determine that the first type of cells includes the at least one cell, stop the electrolytic cell, and repeat the following steps: replace the at least one cell and perform the second test for evaluating whether there is at least one additional cell with the damaged membrane in the electrolytic cell; and Determine that the first type of cells does not include the at least one cell, and continue the normal operation of the electrolytic cell.

18. The combined device according to claim 17, wherein the instructions can be further executed by the at least one processing unit for performing the second classification on the plurality of cells, including determining a cell current efficiency of the electrolytic cell during start-up of the electrolytic cell, the cell current efficiency being determined based on a look-up table associating a current efficiency range of each cell of the electrolytic cell with a time required for each cell to generate chlorine gas after triggering a polarization current in the electrolytic cell.

19. The combined device according to any one of claims 11 to 18, wherein each cell of the electrolytic cell comprises at least a cathode, an anode, and a membrane between the cathode and the anode, and wherein the instructions are executable by the at least one processing unit to perform the second test, comprising injecting a first inert gas into the cathode of each cell of the electrolytic cell using an inert gas leak test system connected to the plurality of cells, injecting a second inert gas into the anode of each cell of the electrolytic cell, and comparing a rate of change of the concentration of an inert gas mixture at an anolyte outlet of the electrolytic cell with a concentration change rate threshold, and further wherein, For a given cell of the electrolytic cell, a rate of change of the concentration of the inert gas mixture greater than the rate of change of concentration threshold indicates that a membrane of the given cell has been damaged, and further wherein a position of the given cell is determined based on a time required for the rate of change of the concentration of the inert gas mixture to exceed the rate of change of concentration threshold.

20. The combined device according to any one of claims 11 to 19, wherein the plurality of cells is one of a plurality of chlor-alkali electrolysis cells and a plurality of non-alkaline water electrolysis cells.

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