In-situ diagnosis method for electrolytic cell

Abstract

The application discloses an electrolytic tank in-situ diagnosis method, comprising the following steps: obtaining the real-time concentration of hydrogen in oxygen, comparing the real-time concentration with the set concentration of hydrogen in oxygen, determining normal if the real-time concentration is consistent with the set concentration of hydrogen in oxygen, and determining abnormal if the real-time concentration is inconsistent with the set concentration of hydrogen in oxygen; after the abnormality occurs, determining whether the running condition deviates, and when the running condition deviates, adjusting based on the sensing parameters to restore the running condition to normal; if there is no running condition deviation, diagnosing the electrolytic tank; wherein the real-time concentration of hydrogen in oxygen and the sensing parameters are detected and obtained by a sensing system. The sensing system is used for multi-point and multi-parameter detection, which simplifies the overall structure and reduces the cost of the instrument. In addition, the sensing system provided by the application transmits signals through optical fibers, is not easy to be affected by external interference to cause distortion or data loss, and improves the safety of the system in remote mountainous areas, islands and other unattended hydrogen production scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolytic hydrogen production, and in particular to an electrolytic cell in-situ diagnosis method. BACKGROUND

[0002] In the process of electrolytic hydrogen production, multiple physical parameters need to be monitored, such as temperature, pressure, flow, liquid level, and gas concentration. In addition to material and processing costs, instruments and meters also account for a large proportion in the entire hydrogen production system. At the same time, the anti-interference ability and the fast and reliable signal transmission ability of the instruments and meters are also the guarantee for the safe operation of the hydrogen production system.

[0003] The current solution is to use multiple independent sensors to detect temperature, pressure and other physical quantities, and then integrate various data and transmit them to the control software. The hardware cost and installation and debugging cost of the instrument are high. In the application scenarios such as offshore wind power hydrogen production, electromagnetic interference, poor signal, and unattended operation, traditional electronic instruments and meters are easily disturbed, leading to sensor failure. The method of relying on network signal transmission cannot feedback fault signals in time, which brings safety hazards. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an electrolytic cell in-situ diagnosis method to solve the technical problems of complex structure, high cost, and easy to be disturbed in the prior art.

[0005] To achieve at least one of the above purposes, the present application provides the following technical solutions:

[0006] In a first aspect, the embodiments of the present application provide a sensing system suitable for a hybrid hydrogen production system, comprising:

[0007] a light source for emitting light;

[0008] a demodulator for receiving light and demodulating the received light;

[0009] a conductive optical fiber connected with the light source and conducting the light emitted by the light source; wherein,

[0010] The conductive optical fiber comprises a conductive section and a detection section, and the detection section has a plurality of detection sections respectively arranged at a plurality of different detection points in the hydrogen production system.

[0011] The conductive section also has a plurality of conductive sections connected between the plurality of detection sections, so that the conductive optical fiber forms an optical channel.

[0012] The detection section is provided with a detection grating, and the light conducted along the conductive optical fiber is partially reflected by the detection grating and partially penetrates the detection grating.

[0013] The demodulator is also connected with the conducting optical fiber, receives and demodulates the light reflected by the detection grating;

[0014] The detection grating is deformed under the action of temperature and / or pressure, and changes the characteristics of the reflected light.

[0015] In some embodiments, a triggering component is further included, which is arranged corresponding to the detection grating;

[0016] The triggering component is configured to convert a change in a parameter other than temperature and / or pressure into a change in temperature and / or pressure in response to the change in the parameter other than temperature and / or pressure, and to apply the temperature and / or pressure to the corresponding detection grating.

[0017] In some embodiments, a reference grating is further arranged on the detection segment, which has the same structure as the detection grating;

[0018] The reference grating is separated from the triggering component.

[0019] In some embodiments, the triggering component is a reactant wrapped around the detection segment and corresponding to the detection grating;

[0020] The reactant reacts with a specific type of substance to be detected, and in response to different concentrations of the substance to be detected, generates different degrees of temperature change and / or shape change;

[0021] The reactant acts on the corresponding detection grating to deform the detection grating.

[0022] In some embodiments, one side of the triggering component is connected with an environment to be detected, and the other side abuts the detection segment at a position corresponding to the detection grating;

[0023] The triggering component is displaced relative to the detection segment under the driving action of the pressure of the environment to be detected, and applies a load to the detection segment.

[0024] In some embodiments, a protective shell is further included, which wraps the outside of the detection segment.

[0025] In some embodiments, a protective sleeve is further included, which is located in the protective shell and connected with the protective shell;

[0026] The detection segment is arranged in the protective sleeve.

[0027] In a second aspect, the embodiments of the present application further provide an in-situ diagnosis method of an electrolytic cell, including the following steps:

[0028] acquiring a real-time concentration of hydrogen in oxygen, comparing the real-time concentration with a set concentration of hydrogen in oxygen, and determining that the concentration is normal if the real-time concentration is consistent with the set concentration, or determining that the concentration is abnormal if the real-time concentration is inconsistent with the set concentration;

[0029] after the abnormality occurs, determining whether an operating condition deviates, and adjusting based on a sensing parameter to restore the operating condition to normal if the operating condition deviates;

[0030] if the operating condition does not deviate, diagnosing the electrolytic cell;

[0031] The real-time concentration of hydrogen in oxygen and the sensing parameter are detected by the sensing system according to any one of the preceding embodiments.

[0032] In some embodiments, the diagnosing of the electrolytic cell includes:

[0033] acquiring a current density i, a partial pressure P of hydrogen gas on the cathode side, and a flux N of permeated hydrogen gas;

[0034] a diffusion permeation coefficient D of the diaphragm and a mass transfer coefficient K of the catalytic layer satisfy the following relationship:

[0035] ;

[0036] ;

[0037] According to the values of i, P, and N detected, fitting values of D and K are acquired;

[0038] The fitting values of D and K acquired are compared with corresponding standard values to determine whether the corresponding diaphragm and catalytic layer have defects;

[0039] wherein S is the solubility of hydrogen gas in water, C is the saturation concentration of hydrogen gas, δ is the thickness of the diaphragm, and F is the Faraday constant.

[0040] In some embodiments, the comparison of the fitting values of D and K acquired with corresponding standard values to determine whether the corresponding diaphragm and catalytic layer have defects includes:

[0041] If the fitting values of D and K are consistent with the corresponding standard values, it is determined that there are no defects;

[0042] If the fitting value of D is larger than the corresponding standard value, it is determined that the diaphragm has a defect of perforation or small thickness;

[0043] If the fitting value of K is larger than the corresponding standard value, it is determined that the catalytic layer has a defect of structural damage.

[0044] In some embodiments, when the operating condition deviates, the adjustment based on the sensing parameters restores the operating condition to normal, specifically:

[0045] Obtaining real-time detection values of each parameter at the corresponding position of the hydrogen production system;

[0046] Comparing the real-time detection values of each parameter with the corresponding set range values of each parameter;

[0047] When there is a deviation between the real-time detection values and the corresponding set range values, adjusting the power of the control component of the corresponding parameter of the hydrogen production system to the real-time detection value of the corresponding parameter within the corresponding set range value.

[0048] In the above technical solution, the sensing system is provided to detect multiple points and multiple parameters of the hydrogen production system. Compared with the prior art of using multiple sensors to detect respectively, the overall structure is simplified, the instrument cost is reduced, and the overall system is more convenient to debug. In addition, the sensing system provided in the embodiments of the present application transmits signals, which is not easy to be distorted or lose data due to external interference, and improves the accuracy of information transmission. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0050] Figure 1 The sensing system provided in some embodiments of the present application detects each point and each parameter of the hydrogen production system;

[0051] Figure 2 The structural schematic diagram of the sensing system provided in some embodiments of the present application;

[0052] Figure 3 The structural schematic diagram of the detection section provided in some embodiments of the present application;

[0053] Figure 4 The structural schematic diagram of the detection section for pressure detection provided in some embodiments of the present application;

[0054] Figure 5 The structural schematic diagram of the detection section for pressure detection provided in some embodiments of the present application;

[0055] Figure 6 The structural schematic diagram of the detection section for pressure detection provided in some embodiments of the present application;

[0056] Figure 7 Structure diagram of the conductive optical fiber and the protective sleeve provided for some embodiments of the present application;

[0057] Figure 8 Structure diagram of the detection section for flow detection provided for some embodiments of the present application;

[0058] Figure 9 Flow node diagram of the diagnostic method provided for some embodiments of the present application;

[0059] Figure 10 Relative relationship diagram of the experimental value and the fitted value of the diffusion coefficient of the diaphragm at different temperatures provided for some embodiments of the present application;

[0060] Figure 11 Relative relationship diagram of the experimental value and the fitted value of the mass transfer coefficient of the diffusion layer at different temperatures provided for some embodiments of the present application.

[0061] The reference signs are as follows:

[0062] 1. Light source;

[0063] 2. Demodulator;

[0064] 3. Conductive optical fiber, 31, conductive section, 32, detection section, 33, detection grating, 34, reference grating;

[0065] 4. Circulator;

[0066] 5. Triggering component;

[0067] 6. Protective shell;

[0068] 7. Protective sleeve. DETAILED DESCRIPTION

[0069] The present application will be further described below by means of the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become more apparent.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and the above description of drawings are intended to cover non-exclusive inclusion.

[0071] The term "example" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as an "example" is not necessarily to be construed as preferred or advantageous over other implementations. While several aspects of embodiments have been disclosed herein, it should be apparent that other aspects can be employed, and that the disclosed aspects, processes, systems, and methods can be modified. All of the information provided herein is meant as illustrative only and should not be construed as limiting the scope of the claims.

[0072] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Although the various aspects of embodiments have been illustrated herein, it should be apparent that other aspects can be employed, and that the disclosed aspects, processes, systems, and methods can be modified. All of the information provided herein is meant as illustrative only and should not be construed as limiting the scope of the claims.

[0073] In the description of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0074] In the description of the present application, the technical term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0075] In the description of the present application, the technical terms "upper", "lower", "inner", "outer", "front", "back", "left", "right", "top", "bottom", etc. indicate the orientation or position relationship based on the working state of the present application, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0076] In the description of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0077] In the description of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or simply indicate that the first feature is higher in horizontal height than the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or simply indicate that the first feature is lower in horizontal height than the second feature.

[0078] In the description of the present application, the meaning of "a plurality of" is more than two (including two), unless otherwise explicitly specified and limited.

[0079] In the description of the present application, the same reference signs represent the same parts, and for the sake of brevity, detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length, etc. of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, etc. of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0080] As part of the inventive concept of the present application, before describing the embodiments of the present application, the reasons for the problems of high cost and detection precision susceptible to interference in the related art for multi-parameter detection of a hydrogen production system are analyzed, and the technical solution of the embodiments of the present application is obtained through reasonable analysis.

[0081] In the related art, various parameters of a hydrogen production system are detected, generally using multiple sensors to detect respectively, and transmitting the detection information to a central control system for corresponding data processing, and detecting the working state of the hydrogen production system according to the collected data; at multiple points to be detected, temperature sensors, pressure sensors, flow sensors, etc. are installed respectively, and the cost of the sensors themselves is high, and the cost of installing and debugging multiple sensors and maintaining them later is also high.

[0082] In some special places, for example, for offshore power generation hydrogen production, the detected information needs to be transmitted over a long distance, but in the traditional way, the sensors collect the corresponding parameter information, and the data is transmitted through the network, and the signal is susceptible to interference, causing distortion of the detected information.

[0083] Therefore, the present application provides a sensing system suitable for a hybrid hydrogen production system and an electrolytic cell in-situ diagnosis method, thereby solving the technical problems of high cost and transmission signal susceptible to interference in the prior art, causing detection information error.

[0084] The technical solutions of the embodiments of the present application are described in detail below with reference to the drawings. The technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0085] For the convenience of describing the following embodiments, the present application takes the sensing system applied to a hybrid hydrogen production system, and the electrolytic cell diagnosis method is taken as an example for a PEM electrolytic cell. In other embodiments, the above sensing system and diagnosis method can also be applied to other hydrogen production systems and electrolytic cell structures, or other structures that need to detect related physical quantities. By making appropriate modifications to the related structures, they can be adapted to the objects to which they are applied.

[0086] In the embodiments of the present application, a sensing system suitable for a hybrid hydrogen production system is provided, referred to as a "sensing system". The sensing system is applied to a hybrid hydrogen production system to detect physical quantities such as temperature, pressure, flow rate, and gas concentration at different points, so as to determine the working condition of the hydrogen production system. Figure 1 The above-mentioned sensing system is used to detect different parameters at different points in the hydrogen production system, including temperature, pressure, flow rate, liquid level, humidity, and gas. It should be noted that the embodiments of the present application only exemplarily show some of the points, and other positions or different parameters corresponding to the positions can also be detected in actual applications.

[0087] The sensing system uses an optical fiber structure, in which grating structures are arranged at different positions on the entire optical fiber. When light is transmitted in the optical fiber and passes through the grating structure, the grating will partially reflect the light. When different temperatures or pressures act on the grating, the grating will deform by a certain amount, which will change the properties of the reflected light, including the wavelength and phase of the reflected light.

[0088] The reflected light is received and demodulated, and the deformation amount of the corresponding grating is obtained according to the correspondence between the wavelength of the light and the shape of the grating. Then, the value of the temperature or pressure acting on the grating to cause the deformation is determined by the deformation amount, so as to realize the detection of temperature and pressure. As for the flow rate and gas concentration, corresponding structures can be arranged to convert them into temperature or pressure acting on the grating to cause deformation, so as to realize the detection of the corresponding parameters.

[0089] Reference Figure 2The sensing system comprises a light source 1, a demodulator 2 and a conducting optical fiber 3. The light source 1 is configured to emit light, and the demodulator 2 is configured to receive the light and demodulate the received light. The conducting optical fiber 3 comprises a plurality of conducting segments 31 and a plurality of detection segments 32. The plurality of detection segments 32 are distributed at a plurality of detection points, and the plurality of conducting segments 31 are connected between the plurality of detection segments 32, so that the conducting optical fiber 3 forms an optical channel. It should be noted that the conducting optical fiber 3 can be provided as an integrated structure, and the conducting segments 31 and the detection segments 32 are different segments of the conducting optical fiber 3. Alternatively, the conducting segments 31 and the detection segments 32 can be provided as separate optical fibers which are connected to form the conducting optical fiber.

[0090] The detection segment 32 is provided with a detection grating 33. The detection grating 33 reflects the light transmitted therethrough. Part of the light is reflected by the detection grating 33, and part of the light penetrates through the detection grating 33 and continues to be conducted along the conducting optical fiber 3. The reflected light is transmitted along the conducting optical fiber 3 to the demodulator 2 for demodulation.

[0091] The light source 1, the demodulator 2 and the conducting optical fiber 3 are connected through a circulator 4. The circulator 4 has at least three ports, and the light source 1, the demodulator 2 and the conducting optical fiber 3 are connected to the first port, the second port and the third port respectively. The circulator 4 is configured to transmit the light in a specific port sequence. The light input from the first port is output from the second port, and the light input from the second port is output from the third port. Through the circulator 4, the light emitted by the light source 1 is conducted along the conducting optical fiber 3, and the reflected light is conducted to the demodulator 4 for demodulation.

[0092] When the light enters the detection grating 33, Bragg reflection occurs. In the case that the grating period and the effective refractive index of the detection grating 33 are determined, the central wavelength of the reflected light can be determined. Under the action of external temperature and pressure, the grating period and the effective refractive index of the detection grating 33 change, that is, the central wavelength of the reflected light changes. Thus, according to the characteristics of the detection grating 33, the change amount of the detection grating 33 corresponding to the wavelength change of the reflected light can be determined, so as to determine the values of the temperature and pressure acting on the detection grating 33.

[0093] It should be noted that the change of the detection grating 33 is not only reflected in the wavelength change of the reflected light, but also in the intensity and phase of the reflected light. In the embodiments of the present application, only the reflected light is demodulated, and the change of the detection grating 33 is determined by the wavelength change. In other embodiments, the change of the detection grating 33 can also be determined by analyzing the intensity and phase change of the reflected light, or by analyzing multiple characteristics, which will not be discussed herein.

[0094] In the hydrogen production system, the changes of multiple positions and multiple parameters need to be monitored, which can be achieved by using one transmission optical fiber 3. The transmission optical fiber 3 is arranged along multiple detection points, and light is transmitted along the transmission optical fiber 3. When passing through each detection grating 33 position, part of the light is reflected, and the reflected light is transmitted to the demodulator 2. The change of the reflected light is determined by demodulation and analysis, and the change of the corresponding detection grating 33, i.e. the change of the grating period and the effective reflectivity, is determined. Only a single light source 1 and a demodulator 2 are needed to complete the corresponding work.

[0095] Compared with the prior art, multiple sensors are arranged and installed at multiple detection points, which effectively reduces the hardware cost of instruments and meters, optimizes the system structure, and is more convenient in installation, debugging, data acquisition and instrument maintenance. In addition, the optical fiber sensing-based long-distance signal transmission method has stronger anti-interference ability, and the long-distance signal transmission effect is better for related scenes such as offshore wind power hydrogen production.

[0096] In actual use, the hydrogen production system not only needs to directly detect temperature and pressure information, but also needs to detect flow, gas concentration and other parameters. Figure 3 The sensing system further includes a triggering component 5, which is arranged corresponding to the detection grating 33. The triggering component 5 is configured to convert the change of the parameter other than temperature and / or pressure into a change of temperature and / or pressure, and apply the converted temperature and / or pressure to the corresponding detection grating 33.

[0097] Specifically, the fluid, gas and moisture act on the triggering component 5, which is converted into a certain temperature and / or pressure through the action of the triggering component 5. In this way, the triggering component 5 can act on the detection grating 33 in the form of temperature and / or pressure. When the flow, gas concentration and humidity change, the temperature and / or pressure acting on the detection grating 33 change, the grating period and effective reflectivity of the detection grating 33 change, and the wavelength of the reflected light changes correspondingly, realizing the detection of multiple parameters.

[0098] It should be noted that the triggering component 5 not only converts the change of the parameter other than temperature and / or pressure into a change of temperature and / or pressure, but also can convert temperature into pressure, or convert pressure into temperature, or transmit or change the direction of pressure. Of course, in actual use, in order to simplify the structure, reduce the cost, ensure the stable operation and other factors, when detecting temperature and pressure, the temperature and pressure can directly act on the corresponding detection grating 33, i.e. when detecting temperature and pressure, whether to set the corresponding triggering component 5 can be selected according to actual needs.

[0099] For example, referring to Figure 3The triggering component 5 is a reactant coated on the detection section 32 at a position corresponding to the detection grating 33, which reacts with a specific type of substance to be detected and generates different degrees of temperature change and / or shape change in response to the change in the amount of the substance to be detected, and the generated temperature change and / or shape change acts on the corresponding detection grating 33, so that the performance of the detection grating 33 changes accordingly.

[0100] Specifically, the reactant is a gas-sensitive coating, which is deposited on the surface of the detection section 32 by using a gas-sensitive material such as platinum, palladium, etc., which can be used to detect the concentration of hydrogen in oxygen. Platinum and palladium change in temperature and shape by adsorbing hydrogen or reacting with hydrogen, and the temperature change acts on the detection grating 33, or the shape change exerts different pressures on the detection grating 33, which will cause the properties of the detection grating 33 to change, so as to determine the corresponding gas concentration, pressure, etc.

[0101] In another embodiment, the triggering component 5 is a high polymer film deposited on the outer periphery of the detection section 32. When the humidity in the environment changes, the high polymer film will swell or shrink accordingly, generating a stress change that acts on the corresponding detection grating 33, changes the characteristics of the detection grating 33, and is reflected in the change in the properties of the reflected light, achieving detection of humidity.

[0102] That is, by setting the reactant on the detection section 32 to interact with the substance to be detected, the temperature change and stress change generated under the action of physical and / or chemical changes act on the detection grating 33, and the corresponding change in the reflected light is detected to determine the value of the parameter to be detected.

[0103] Reference Figure 4 The sensing system is also provided with a protective shell 6, which is coated on the outer side of the detection section 32. On the one hand, it can better protect the detection section 32, and on the other hand, by setting the protective shell 6, it is more convenient to install the triggering component 5 and to keep the stability of the force exerted by the triggering component 5 on the detection grating 33 under the detection of pressure.

[0104] Specifically, the protective shell 6 is a sleeve structure made of metal material, the transmission optical fiber 3 passes through the protective shell 6, and the detection section 32 is located in the protective shell 6. The triggering component 5 is connected with the protective shell 6 and at least part of it can displace relative to the protective shell 6. That is, the triggering component 5 can be connected with the protective shell 6 in a sliding manner, and under the action of pressure, it can slide relative to the protective shell 6, or the triggering component 5 can be deformed under the action of pressure to exert a force on the detection grating 33. One side of the triggering component 5 is connected with the environment to be detected, and the other side abuts against the position on the detection section 32 corresponding to the detection grating 33.

[0105] The trigger component 5 is driven by the pressure of the environment to be detected, and can be displaced relative to the part of the protective shell 6, that is, relative to the detection section 32. In the case of different pressures of the environment to be detected, the load applied by the trigger component 5 to the detection section 32 and the detection grating 33 is also different, which in turn affects the characteristics of the reflected light. By demodulating and analyzing the reflected light, the corresponding pressure can be determined.

[0106] For example, referring to Figure 4 , the trigger component 5 is a metal diaphragm. The pressure of the environment to be detected acts on the metal diaphragm, causing the metal diaphragm to deform. The deformed part of the metal diaphragm is fixedly connected to an abutting protrusion on the side facing the detection section 32. In the initial state, the abutting protrusion is in close contact with the detection section 32. When the metal diaphragm is subjected to external pressure, the metal diaphragm deforms, and the abutting protrusion presses the detection section 32, causing the corresponding detection grating 33 to deform.

[0107] For example, referring to Figure 5 , a schematic diagram of detecting the liquid level using the sensing system is shown. The protective shell 6 is fixedly connected to the bottom of the corresponding container. The side of the metal diaphragm facing away from the detection grating 33 is in communication with the inside of the container. The liquid in the container contacts the metal diaphragm, and the stress generated by the pressure acts on the metal diaphragm, causing the metal diaphragm to deform. The rise and fall of the liquid level in the container changes the pressure at the metal diaphragm, which in turn changes the amount of deformation of the metal diaphragm and the pressure acting on the metal diaphragm. The detection grating 33 deforms, achieving detection of the liquid level.

[0108] Figure 4 One of the load application methods is only exemplary in the embodiment. In other embodiments, the load can also be applied to the detection grating in different directions. For example, referring to Figure 6 , the load is applied to the detection grating 33 along the radial direction of the transmission optical fiber 3.

[0109] In addition, in order to avoid the problem of damage to the detection grating 33 or the transmission optical fiber 3 caused by the applied pressure load, referring to Figure 4 and Figure 6 , a protective sleeve 7 is wrapped around the corresponding detection section 32 during pressure detection. For example, the protective sleeve 7 is made of flexible polymer material. On the one hand, it ensures that the load is smoothly transmitted to the detection grating 33. On the other hand, it can provide good protection for the transmission optical fiber 3. In actual use, the protective sleeve 7 is connected to the protective shell 6, which can more conveniently limit the position of the transmission optical fiber 3 relative to the protective shell 6, facilitating the layout of the transmission optical fiber 3.

[0110] For example, referring to Figure 7The arrangement structure of the conductive optical fiber 3 is exemplarily shown, and the protective sleeve 7 is arranged to assist in fixing the position of the conductive optical fiber 3. When detecting pressure, the stability of the pressure applied on the corresponding detection grating 33 can be improved.

[0111] With reference to Figure 8 When detecting flow, the trigger component 5 is fixedly connected to the protective sleeve 7, and the trigger component 5 is divided into a force receiving part and a connecting part. The connecting part is fixedly connected to the protective sleeve 7, and the cross-sectional area of the force receiving part perpendicular to the fluid flow direction is greater than the cross-sectional area of the connecting part perpendicular to the fluid flow direction. The flow size can be more accurately detected, and the detection of small changes is more sensitive. In other embodiments, the flow direction of the fluid can be perpendicular to the extension direction of the detection section 32.

[0112] With reference to Figure 3 The detection section 32 is further provided with a reference grating 34 corresponding to the detection grating 33. The reference grating 34 has the same structure as the detection grating 33, and the reference grating 34 is kept separate from the trigger component. When detecting parameters such as pressure, flow, oxygen-hydrogen concentration, and humidity, the detection grating 33 is not only affected by the state applied by the trigger component 5, but also affected by the temperature of the environment, which can affect the accuracy of the detection result of the detection grating 33 and cause errors. By combining and analyzing the reflected light of the detection grating 33 and the reflected light of the corresponding reference grating 34, the change in the reflected light of the detection grating 33 caused by factors other than the to-be-detected parameters can be removed, and the proportion of the change caused by the to-be-detected parameters can be obtained. The influence of other irrelevant factors in the environment can be eliminated, and the accuracy of the detection result can be improved.

[0113] In the case of the protective sleeve 7, the reference grating 34 should also be located in the protective sleeve 7 to keep the same environment as the corresponding detection grating 33.

[0114] In addition, the present application also provides an electrolytic cell in-situ diagnosis method, which is realized based on the above-mentioned sensing system, with reference to Figure 9 The above-mentioned method is a real-time flow node schematic diagram, which specifically includes the following steps.

[0115] Firstly, the sensing system is used to detect the parameters of the hydrogen production system, and the real-time concentration of oxygen-hydrogen is obtained. The real-time concentration of oxygen-hydrogen is compared with the set oxygen-hydrogen concentration. If the real-time concentration is consistent with the above-mentioned concentration, it is determined to be normal. If the real-time concentration is not consistent with the above-mentioned concentration, it is determined to be abnormal. The set oxygen-hydrogen concentration is the factory value of the equipment, which can be determined according to the corresponding standard of the hydrogen production system. The specific determination method is well known to those skilled in the art, and will not be described here.

[0116] If the determination result is normal, it indicates that the hydrogen production system is running normally, and no subsequent adjustment and detection steps are needed.

[0117] When the above determination is abnormal, it is necessary to determine whether the operating condition of the hydrogen production system deviates. If the operating condition deviates, adjustment is made based on the sensing parameters obtained by the sensing system until the operating condition returns to normal. If the operating condition does not deviate, there is a risk of electrolytic cell structure failure or damage, and the electrolytic cell needs to be diagnosed to determine whether the electrolytic cell structure has a fault and the specific type of the fault.

[0118] The operating condition specifically refers to whether the operating parameters such as temperature, pressure, and flow rate are within the set normal operating range. Deviation of the operating condition can be caused by multiple factors. For example, low power of the cooling system or failure of the cooling system or blockage of the cooling pipeline can cause abnormal temperature rise. Lack of necessary insulation measures can cause excessively low temperature. Fault of the pressure regulating valve or abnormal operation of the hydrogen compressor can cause excessively high system pressure. Leakage of components or poor sealing of connection points can cause excessively low system pressure.

[0119] To determine whether the operating condition deviates, adjustment is made based on the relevant parameters detected by the sensing system when the operating condition deviates, so that the operating condition returns to normal. In the process, the corresponding parameters of the hydrogen production system are detected based on the sensing system. Specifically, the real-time detection values of temperature, pressure, and flow rate at the corresponding positions of the hydrogen production system are obtained by the sensing system. Of course, in other embodiments, related parameters such as humidity and gas concentration can also be included. In the embodiments of the present application, temperature, pressure, and flow rate are used as exemplary descriptions, but this does not limit the application scenarios of the present application.

[0120] Then, the obtained real-time detection values of temperature, pressure, and flow rate are compared with the set range values of temperature, pressure, and flow rate. If the obtained real-time detection values are within the corresponding set range values, it indicates that the operating parameters have not deviated from the operating condition. If the real-time detection values deviate from the corresponding set range values, the power of the corresponding parameter adjustment component of the hydrogen production system is adjusted until the real-time detection value of the corresponding parameter is within the corresponding set range value.

[0121] For example, if the real-time detection value of the temperature is too high, the corresponding adjustment component, i.e., the working power of the cooling system, is adjusted to increase the cooling power and reduce the temperature until the real-time detection value of the temperature is within the corresponding set range value.

[0122] Of course, in actual operation, if the corresponding control component is adjusted for a certain period of time, the corresponding parameter still does not return to the normal value, the corresponding component needs to be detected to determine whether there is a structural damage problem, and corresponding maintenance work is needed in time.

[0123] In addition, if there is no deviation of the above operating condition, the electrolytic cell needs to be diagnosed. Specifically, through the change of the corresponding parameters during the operation of the electrolytic cell, the working state of the corresponding components can be reflected. Specifically, the electrolytic cell includes a diaphragm and a catalyst layer. When the diaphragm and the catalyst layer are in a constant working environment state, for example, when they are in a state of a certain temperature and pressure, the diffusion coefficient D of the diaphragm and the mass transfer coefficient K of the catalyst layer are determined, that is, the properties of the diaphragm and the catalyst layer are determined.

[0124] In this way, after obtaining the temperature and pressure parameter values, the amount of hydrogen permeated by the diaphragm and transmitted by the catalyst layer can be determined. If there is a deviation between the flux N of hydrogen permeated by the diaphragm and the predetermined value, or there is a deviation between the hydrogen partial pressure P on the cathode side and the predetermined value, it indicates that the properties of the diaphragm or the catalyst layer have changed, that is, D and K have changed. N is determined by measuring the concentration of hydrogen in oxygen, and P is determined by measuring the hydrogen pressure on the cathode side. Of course, the above situation is determined when the working power of the electrolytic cell is determined, that is, the working current density i is determined.

[0125] Most of the hydrogen produced by the cathode in the electrolytic cell is discharged to the outlet direction through the catalyst layer, and a small part penetrates the diaphragm to the anode. These two processes are related to the catalyst layer and the diaphragm material respectively. Most of the hydrogen permeated through the diaphragm is transmitted in the form of dissolved hydrogen, which can be described by Fick's diffusion law. Based on the above two points, the diffusion equation and the mass conservation equation are established to satisfy the following relationship:

[0126] ;

[0127] ;

[0128] Where S is the solubility of hydrogen in water, P is the hydrogen partial pressure on the cathode side, C is the saturation concentration of hydrogen, δ is the thickness of the diaphragm, and F is the Faraday constant.

[0129] In actual operation, S, C, δ, and F in the above relationship are all fixed values, N and P can be measured by the aforementioned sensing system, and the value of i is the set value of the hydrogen production system. Thus, by obtaining the corresponding values ​​of N, P, and i during the hydrogen production process, and based on the above relationship, the permeability coefficient D of the membrane and the mass transfer coefficient K of the catalyst layer can be fitted. By comparing the fitted values ​​of D and K with the standard values ​​(historical values ​​or equipment factory values) that the membrane and catalyst layer should maintain in the corresponding working environment, the structural information of the membrane and catalyst layer can be determined. Based on the comparison information, it can be determined whether the membrane and catalyst layer have malfunctioned, and what type of malfunction exists.

[0130] refer to Figure 10 The trend of the membrane permeability coefficient D with temperature includes the value of permeability coefficient D determined by experimental testing (i.e., the standard value) and the fitted value of permeability coefficient D obtained by fitting the above relationship. It can be seen that the fitted value of permeability coefficient D is basically the same as the actual value of permeability coefficient D (i.e., the standard value).

[0131] Additionally, refer to Figure 11 The diagram shows the relationship between the mass transfer coefficient of the catalyst layer and temperature. It also includes the actual value (i.e., the standard value) of the mass transfer coefficient K determined by experiments, as well as the fitted value of the mass transfer coefficient K obtained by fitting the above relationship. Similarly, the fitted value of the mass transfer coefficient K is basically the same as the actual value (i.e., the standard value) of the mass transfer coefficient K.

[0132] As can be seen from the above, based on the fitting relationship provided in the embodiments of this application, and combined with the values ​​of relevant parameters detected in real time, the fitting values ​​of the permeability coefficient D of the diaphragm and the mass transfer coefficient K of the catalyst layer can be accurately obtained. That is, the structural defects of the diaphragm and catalyst layer can be accurately determined based on the obtained fitting values. In addition, the "basically the same" in the embodiments of this application means that the two values ​​are the same, or the difference is within the allowable error range.

[0133] Based on the aforementioned sensing system and corresponding methods, the values ​​of permeability coefficient and mass transfer coefficient can be determined relatively easily and accurately, which helps to determine whether the corresponding membrane and catalyst layer have malfunctions and to carry out timely maintenance and repair.

[0134] In actual operation, the permeation coefficient D of the diaphragm and the mass transfer coefficient K of the catalytic layer are obtained by fitting according to the above method; then, the predetermined values of D and K are determined according to the temperature values obtained by using the above sensing system, and the corresponding structure information of the diaphragm and the catalytic layer can be determined by comparison. If the value of D obtained by fitting is too large, it indicates that the thickness of the diaphragm is thinned (the resistance of the permeation diaphragm is reduced) or there is a pinhole defect (the number of permeation channels increases, and the interface size of the permeation channel increases), wherein the thickness reduction of the diaphragm may be caused by chemical attenuation or other reasons; if the value of K obtained by fitting is too small, it indicates that the structure of the catalytic layer is damaged, and there is a related type of fault such as the hydrogen transmission channel being damaged. For the type of specific fault, after the mass transfer coefficient K of the catalytic layer is determined, the type of specific fault can be determined according to the existing technology in the art.

[0135] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for in-situ diagnosis of an electrolytic cell, characterized in that, Includes the following steps: The real-time concentration of hydrogen in oxygen is obtained and compared with the set concentration of hydrogen in oxygen. If the real-time concentration matches the set concentration of hydrogen in oxygen, it is determined to be normal; otherwise, it is determined to be abnormal. After the anomaly occurs, it is determined whether the operating conditions have deviated, and if the operating conditions deviate, adjustments are made based on the sensor parameters to restore the operating conditions to normal. If there is no deviation from the operating conditions, then the electrolytic cell should be diagnosed. The real-time hydrogen concentration in oxygen and the sensing parameters are obtained by a sensing system, which includes: a light source for emitting light; a demodulator for receiving and demodulating the received light; and a conductive optical fiber connected to the light source to conduct the light emitted by the light source. The conductive optical fiber includes a conductive section and a detection section. Multiple detection sections are placed at different detection points in the hydrogen production system. Multiple conductive sections are also provided, connected between the multiple detection sections, forming an optical channel. A detection grating is provided within each detection section. Light conducted along the conductive optical fiber is partially reflected by the detection grating and partially penetrates it. The demodulator is also connected to the conductive optical fiber to receive and demodulate the light reflected by the detection grating. The detection grating deforms under temperature and / or pressure, changing the characteristics of the reflected light. The diagnosis of the electrolyzer includes: Obtain the current density i, the partial pressure P of hydrogen on the cathode side, and the flux N of hydrogen permeation; The diffusion permeation coefficient D of the membrane and the mass transfer coefficient K of the catalyst layer satisfy the following relationship: ； ； Based on the detected values ​​of i, P, and N, obtain the fitted values ​​of D and K; The fitted values ​​of D and K are compared with the corresponding standard values ​​to determine whether there are defects in the corresponding membrane and catalyst layer. Where S is the solubility of hydrogen in water, C is the saturation concentration of hydrogen, δ is the thickness of the diaphragm, and F is the Faraday constant.

2. The in-situ diagnostic method for electrolytic cells according to claim 1, characterized in that, The step of comparing the obtained fitted values ​​of D and K with the corresponding standard values ​​to determine whether there are defects in the corresponding membrane and catalyst layer includes: If the fitted values ​​of D and K match the corresponding standard values, then it is determined that there is no defect. If the fitted value of D is larger than the corresponding standard value, it is determined that the diaphragm has defects such as perforation or thinning. If the fitted value of K is smaller than the corresponding standard value, it is determined that the catalyst layer has a defect of structural damage.

3. The in-situ diagnostic method for electrolytic cells according to claim 1, characterized in that, When the operating conditions deviate from the normal range, adjustments are made based on sensor parameters to restore the operating conditions to normal. Specifically: Obtain real-time detection values ​​of various parameters at corresponding locations in the hydrogen production system; Compare the real-time detection values ​​of each parameter with the corresponding set range values ​​of each parameter; When the real-time detected value deviates from the corresponding set range value, the power of the control component of the corresponding parameter in the hydrogen production system is adjusted until the real-time detected value of the corresponding parameter is within the corresponding set range value.

4. The in-situ diagnostic method for electrolytic cells according to claim 1, characterized in that, It also includes a triggering component, which is configured correspondingly to the detection grating; The triggering element is configured to respond to a parameter change other than temperature and / or pressure, convert the parameter change other than temperature and / or pressure into a temperature and / or pressure change, and apply the temperature and / or pressure to the corresponding detection grating.

5. The in-situ diagnostic method for electrolytic cells according to claim 4, characterized in that, The detection section is also provided with a reference grating, which has the same structure as the detection grating. The reference grating is separated from the triggering component.

6. The in-situ diagnostic method for electrolytic cells according to claim 4 or 5, characterized in that, The triggering component is a reactant wrapped around the detection segment at a position corresponding to the detection grating; The reactants react with a specific type of analyte and, in response to different concentrations of the analyte, produce varying degrees of temperature and / or shape changes. The reactant acts on the corresponding detection grating, causing the detection grating to deform.

7. The in-situ diagnostic method for electrolytic cells according to claim 4 or 5, characterized in that, One side of the triggering component is connected to the environment to be detected, and the other side abuts against the corresponding position of the detection grating on the detection segment. The triggering component is displaced relative to the detection segment under the pressure of the environment to be detected, thereby applying a load to the detection segment.

8. The in-situ diagnostic method for electrolytic cells according to claim 7, characterized in that, It also includes a protective shell that covers the outside of the detection section.

9. The in-situ diagnostic method for electrolytic cells according to claim 8, characterized in that, It also includes a protective sleeve, which is located inside the protective shell and connected to the protective shell; The detection section is installed inside the protective sleeve.

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