Electrolysis device, method for measuring concentration of gas component in electrolysis device, computer program product, use of measurer and simulation program product

Abstract

The invention relates to an electrolysis device, to a method for measuring the concentration of a gas component in an electrolysis device, to a computer program product, to the use of a measurer and to a simulation program product. The electrolysis device (10) comprises a separation membrane (16) for generating hydrogen (13) and oxygen (15) from water. The electrolysis device (10) has a first line (12) for discharging hydrogen (15) in the hydrogen fluid (17), in the region of which a measuring device (20) for detecting impurities (18), for example oxygen impurities, in the hydrogen fluid (17) is arranged. According to the invention, the measuring device (20) is designed to detect an acoustic characteristic variable in the hydrogen fluid (17). The invention also relates to a method (100) which can be used for determining the concentration (32) of the impurity (18) in the electrolysis device (10). The invention further relates to a computer program product (45) which can be used to carry out such a method (100) and to a simulation program product (60) which can be used to simulate the operating behavior of such an electrolysis device (10). The invention further relates to the use of a measuring device (20) in an electrolysis device (10), said measuring device being designed to measure the velocity (42) of sound in a mixed gas (11).

Description

TECHNICAL FIELD

[0001] The present invention relates to an electrolysis device and a method for concentration measurement of a gas component in such an electrolysis device. The invention likewise relates to a computer program product for carrying out such a method and a corresponding application of a measuring device. Furthermore, the invention also relates to a simulation program product for simulating the operating behavior of a corresponding electrolysis device. BACKGROUND

[0002] From the international application WO 2022 / 039596 Al a MEMS (Micro Electro Mechanical System) based microphone is known which has a body with a recess, a resonator and a ventilation system. The resonator is designed to vibrate at a mechanical resonance frequency which is higher than a characteristic equilibrium frequency.

[0003] The document "Speed of sound measurements in gas-mixtures at varying compositions using an ultrasonic gas flow meter with silicon based transducers" (authors Torbjoern Loefqvist, Kestutis Sokas and Jerker Delsing) describes speed of sound measurements in monoatomic, diatomic and triatomic gases. Herein argon, oxygen or carbon dioxide are added to air or nitrogen as additives. The document discloses that by temperature and speed of sound measurements the concentration and molar composition of the respective mixed gas can be determined.

[0004] The patent application IN 201941019317 A discloses a method for determining the concentration of a gas in a mixed gas. The method is based on the photoacoustic spectroscopy technique and is used to make the concentration of a mixed gas component influence the speed of sound therein. SUMMARY

[0005] Hydrogen and oxygen in molecular form are produced when an electrolysis device is in operation. The formation of ignitable detonation gas mixtures is to be avoided. Wear of the separation membrane in an electrolysis device can lead to the occurrence of oxygen impurities on the hydrogen side of the separation membrane. A method is required which is able to detect such oxygen impurities safely, quickly and reliably. It is the basic object of the present invention to provide a feasible solution which advantageously identifies the production of potentially dangerous mixed gases in an electrolysis device.

[0006] The object is achieved by an electrolysis device according to the invention. The electrolysis device comprises a separation membrane which is designed for electrolytic separation of water thereon, separating the water into hydrogen and oxygen, i.e. into substantially molecular hydrogen and substantially molecular oxygen. The hydrogen produced thereat can be conducted as a hydrogen fluid. Likewise, the oxygen produced at the separation membrane can be conducted as an oxygen fluid. The electrolysis device further comprises a first conduit which is designed for conducting the hydrogen fluid, for example into a compressor or a container. In the region of the first conduit, a measuring device is provided which is designed for detecting impurities, for example oxygen impurities and / or nitrogen impurities, in the hydrogen fluid. The measuring device can be in fluid connection with the first conduit and can be traversed by a portion of the hydrogen fluid. The measuring device can be designed for monitoring the impurities, in particular oxygen impurities and / or nitrogen impurities, in the hydrogen fluid periodically or continuously. According to the invention, the measuring device is designed for detecting an acoustic characteristic variable in the hydrogen fluid. By detecting this acoustic characteristic variable, the presence of oxygen impurities in the hydrogen fluid can be detected. The invention is based, inter alia, on the recognition that oxygen impurities cause a significant change in the acoustic characteristic variable in the hydrogen fluid, even at low concentrations. In particular, the change in the acoustic characteristic variable caused by oxygen impurities in the hydrogen fluid is significantly stronger than the change caused by hydrogen impurities in the oxygen fluid at the corresponding inverse concentration ratio. Thus, the electrolysis device according to the invention can ensure early identification of oxygen impurities in the hydrogen fluid. Likewise, by identifying the presence of oxygen impurities in the hydrogen fluid, the automatic identification of a damaged or worn separation membrane in the electrolysis device can be accelerated. Below the limit value at which oxygen impurities can cause an explosion hazard, the rapid identification of a damaged or worn separation membrane makes it possible to replace the separation membrane in time, in order to ensure efficient operation of the electrolysis device. Furthermore, after flushing the electrolysis cell with nitrogen, a reduction in nitrogen impurities is detectable. By precise measurement, it is identifiable when the electrolysis device can resume production operation and obtain a sufficiently pure hydrogen output. The electrolysis device according to the invention can thus be operated safely, reliably and economically on a continuous basis in a simple manner.

[0007] In one embodiment of the electrolysis device as claimed, the acoustic characteristic variable for detecting impurities is the speed of sound in the hydrogen fluid. In particular, the speed of sound in the hydrogen fluid changes significantly when oxygen impurities and / or nitrogen impurities are present in the hydrogen fluid. When 0.1 volume percent of hydrogen is added to an otherwise pure oxygen fluid, the density of the mixed gas changes by about 0.001 kg / m3, from 1.428 kg / m3to 1.429 kg / m3. 3 When 0.1 volume percent of oxygen is added to an otherwise pure hydrogen fluid, the density of the mixed gas likewise changes by about 0.001 kg / m3, from 0.085 kg / m3to 0.084 kg / m3. 3 3 When 0.1 volume percent of oxygen is added to an otherwise pure hydrogen fluid, the density of the mixed gas likewise changes by about 0.001 kg / m3, from 0.085 kg / m3to 0.084 kg / m3. 3 3 When 0.1 volume percent of oxygen is added to an otherwise pure hydrogen fluid, the density of the mixed gas likewise changes by about 0.001 kg / m3, from 0.085 kg / m3to 0.084 kg / m3. 3 ​​. Thus, there is a relative density change of about 16 times higher in a hydrogen fluid with oxygen impurities than in an oxygen fluid with hydrogen impurities. Since oxygen and nitrogen have a similar molecular weight, nitrogen impurities also have a similar effect. The speed of sound in the respective mixture gas depends on its density. Thus, it is possible to detect the speed of sound in a hydrogen fluid with incorporated oxygen impurities and / or nitrogen impurities, and thus to detect the relative density change. Accordingly, the measurer in the electrolysis device as claimed can be designed as a sound speed measurer. Such a sound speed measurer is readily available and provides a higher measurement accuracy. Thus, even at low oxygen or nitrogen concentrations, impurities in the hydrogen fluid can be reliably identified.

[0008] Furthermore, the measurer can be designed for exciting and detecting an acoustic resonance in a sample of matter taken from the hydrogen fluid. The measurer can have a measurement chamber which is essentially elongated, i.e. prismatic, into which the sample of matter can be introduced. The measurement chamber can have end faces at both ends and be designed such that the sample of matter introduced from the hydrogen fluid flows essentially in a longitudinal direction, i.e. from one end face to the opposite end face, through the measurement chamber. For exciting the acoustic resonance, at least one end face can be provided with a sound emitter, also referred to as a transducer. The sound emitter can be designed in particular as a piezoelectric transducer. The sound emitter can be driven by a frequency generator, which can be connected to a control unit, for tuning. The excited acoustic resonance can be a first, second, etc. harmonic vibration mode. Thus, it is possible to precisely measure the frequency of the harmonic vibration mode in the sample of matter and thus to reliably determine the speed of sound present therein. In particular, the frequency generator can be designed for exciting a third or fourth harmonic longitudinal vibration in the measurement chamber. These vibrations exhibit a significant change in the resonance frequency with increasing oxygen concentration in the sample of matter. Thus, the ease and accuracy of the speed of sound measurement is ensured. The reliability of the impurity detection, in particular the oxygen impurity detection, in the hydrogen fluid is further improved thereby.

[0009] In a further embodiment of the electrolysis device as claimed, the measurer has a microphone, which can be arranged in the measurement chamber. The microphone can be arranged centrally along the main axis, in particular at a central position of the measurement chamber. The main axis extends essentially from one end face of the measurement chamber to the opposite end face. The longitudinal direction of the measurement chamber is essentially defined by the orientation of the main axis. By the central positioning of the microphone, there is an anti-node of the even order harmonic vibration at this point. In the region of the anti-node, in particular at its extreme points, there is a maximum amplitude, i.e. acoustic loudness. In the case of even order harmonic vibrations, there is always a central anti-node in the measurement chamber which can be detected by the microphone. Thus, the measurement chamber requires only one microphone or one microphone arrangement arranged centrally along the main axis. Thus, the measurer and the electrolysis device as claimed can be manufactured economically and efficiently. Furthermore, by the thus reduced number of components, the risk of component failure is reduced. The measurer overall provides a higher measurement accuracy and an enhanced robustness.

[0010] Furthermore, the measurer can comprise at least one further microphone arranged in the measuring chamber. By using multiple microphones, an enhanced measurement signal can be generated, allowing for more precise measurements, in particular more precise speed of sound measurements in the hydrogen fluid.

[0011] Furthermore, the measurer can be equipped with an evaluation unit designed to determine the concentration of impurities in the hydrogen fluid. The evaluation unit can in particular be designed to quantitatively determine the present impurities based on the measurement signals generated when carrying out the measurement process in the measuring chamber. To this end, the change in the speed of sound of the substance sample in the hydrogen fluid can be detected and based thereon the relative density difference with respect to a pure hydrogen fluid can be determined. Based on the relative density difference, the concentration of the impurities can be quantified. The evaluation unit can be equipped with a suitably designed computer program product. Furthermore, the evaluation unit can be designed as a functional unit of a control unit with which the measurer can be equipped. The evaluation unit can also be designed to output a warning to a user and / or a data interface when the detected oxygen impurity concentration numerically exceeds a predefinable limit value. Correspondingly, a notification about a drop in the nitrogen impurity concentration can also be output when the nitrogen impurity concentration numerically falls below a corresponding predefinable limit value. Alternatively or additionally, control instructions for predefining the operating mode of the electrolysis device can be output. Thereby, the automatic reaction behavior of the electrolysis device can be adjusted in a targeted manner overall. The electrolysis device claimed can thus be adapted to a wide range of safety requirements and can be operated economically.

[0012] In particular, the evaluation unit can have a bandpass filter. The bandpass filter can be designed to evaluate at least the measurement signals from the microphone of the middle section in the measuring chamber. The bandpass filter can also be designed to additionally evaluate the measurement signals from the at least one further microphone. By using the bandpass filter, for example, noise can be reduced, allowing for more precise measurements, in particular speed of sound measurements in the hydrogen fluid.

[0013] Furthermore, the measurer of the electrolysis device claimed can be equipped with a temperature measurer. The temperature measurer can be designed as a temperature sensor and be designed to detect the temperature of the substance sample in the measuring chamber. Likewise, the measurer can be designed to carry out a temperature compensation when determining the speed of sound in the substance sample based on the temperature detected by the temperature measurer. Thereby, the influence of the temperature on the measured speed of sound can be compensated for, allowing for precise concentration measurements. The measurer can function properly over a wide temperature range of the hydrogen fluid and can thus be installed at any position on the first pipe carrying the hydrogen fluid. Thereby, an existing electrolysis device can be easily retrofitted.

[0014] In another embodiment of the application, the measuring device on the electrolysis device can be equipped with a pressure sensor. The detection of the concentration of oxygen mixed with hydrogen is related to the pressure. In particular, there is a proportional relationship in the gas density measurement to the measured gas pressure. Accordingly, the measuring device can be designed to determine the concentration of impurities by pressure compensation. Alternatively or additionally, the hydrogen concentration in a substance sample from the hydrogen fluid can be determined by pressure-compensated measurement. The achievable measurement accuracy is thus further improved.

[0015] Furthermore, the side face, which essentially delimits the measuring chamber between the end faces along the main axis, can be formed by a profile body, in particular an extruded profile body. The profile body can have a wall thickness, by which an essentially uniform temperature distribution is produced along the side face. Accordingly, the temperature distribution in the measuring chamber is likewise essentially uniform. The profile body can be made of a metallic material, for example an aluminum alloy or a copper alloy. The higher the thermal conductivity of the profile body, the better. The higher the wall thickness of the profile body, the greater the thermal inertia of the profile body, which stabilizes the uniform temperature distribution in the sleeve surface and in the measuring chamber. The profile body can be manufactured economically and efficiently in a wide range of wall thicknesses. The measuring device can thus be manufactured economically and efficiently, while the measurements carried out by it have better reproducibility.

[0016] Furthermore, the electrolysis device can be equipped with a database, which stores the concentration of oxygen impurities as historical measurement data and provides for evaluation. The database can be designed as a component of the electrolysis device control unit. The historical measurement data can be collected on the electrolysis device itself and / or on electrolysis devices of the same construction. The database can be evaluated by means of a simulation program product, in which the electrolysis device is mapped, for example as a digital twin. Causes for an increase in the oxygen impurity concentration in the hydrogen fluid can thus be diagnosed in a targeted manner, which in turn allows a safe operation of the electrolysis device.

[0017] The object is likewise achieved by a method for detecting impurities, for example oxygen impurities and / or nitrogen impurities, in hydrogen in a hydrogen fluid in an electrolysis device according to the application. The hydrogen fluid is introduced into a first pipe. The method comprises a first step, in which the electrolysis device is operated. During operation of the electrolysis device, molecular hydrogen is produced at a separation membrane. When the separation membrane is damaged or worn, oxygen impurities are produced, which form a mixed gas together with the molecular hydrogen and are introduced into the first pipe. After flushing with nitrogen, nitrogen impurities can remain, which are mixed with the hydrogen. The purity, i.e. the quality, of the hydrogen produced is thus reduced. The impurities in the hydrogen fluid need to be detected during the method according to the application. The method comprises a second step, in which the speed of sound in the mixed gas conveyed through the first pipe is determined. To this end, the electrolysis device can be equipped with a corresponding measuring device, which is in fluid communication with the first pipe. For detecting the speed of sound in the mixed gas, a substance sample from the hydrogen fluid in the first pipe can be introduced into a measuring chamber of the measuring device. In the second step, it is also provided to compare the detected speed of sound with a reference speed of sound.

[0018] The method according to the application further comprises a third step in which the concentration of the impurities in the mixed gas is determined depending on the result of the comparison in the second step. The difference between the determined speed of sound and the reference speed of sound forms a favorable measure for the concentration of the impurities in the hydrogen fluid, i.e. a measure in the mixed gas. Furthermore, in the third step a warning is issued when the determined concentration of oxygen impurities exceeds a predefinable limit value in terms of magnitude. The warning can be output to a user and / or a data interface. Furthermore, a control command can likewise be output by means of which the operating mode of the electrolysis device can be predefinable. To this end, the electrolysis device, in particular the measuring cell, can be equipped with an evaluation unit on which a corresponding executable computer program product can be stored.

[0019] The method according to the application advantageously enables a reliable detection of low concentrations of oxygen impurities, so that a risk-mitigating intervention in the operation of the electrolysis device can be made as early as possible. In particular, a damaged or worn-out separation membrane in the electrolysis device can be quickly identified. By replacing the separation membrane as early as possible, a particularly efficient operation of the electrolysis device can be achieved. It is likewise possible to identify whether the nitrogen impurities have been sufficiently flushed in order to produce hydrogen having the desired purity. This enables the electrolysis device to be operated particularly economically.

[0020] In the method as claimed, the underlying electrolysis device can be designed according to one of the above-described embodiments. The features of the above-described electrolysis device can be applied directly to the method as claimed, individually or in combination. The method as claimed is therefore suitable for a variety of different electrolysis devices.

[0021] In a further embodiment of the method as claimed, the temperature and / or the pressure of the detected mixed gas is taken into account in the second step for determining the speed of sound. Accordingly, the determination of the speed of sound is carried out with temperature compensation and / or pressure compensation. By means of temperature compensation and / or pressure compensation, an adaptive adjustment of the substance sample to be detected, i.e. a pretreatment of the substance sample to reference conditions, becomes unnecessary. By means of the method as claimed, the presence of oxygen impurities in a substance sample having a wide range of thermodynamic states, i.e. temperatures and pressures, can be directly detected. The pressure and temperature compensation can be implemented by means of pure algebraic operations or characteristic maps, so that a technically expedient solution in terms of saving of computing resources can be achieved. The method as claimed is therefore characterized by speed, robustness and precision. To this end, the electrolysis device can be equipped with a corresponding temperature measuring cell which can be designed for detecting the temperature of the substance sample in the measuring cell. Furthermore, the measuring cell can be equipped with a corresponding pressure sensor which can be provided for detecting the pressure of the substance sample in the measuring cell. The pressure and temperature of the substance sample from the hydrogen fluid can be detected precisely and intrinsically safe. The execution of the temperature compensation and / or the pressure compensation can be implemented by means of an evaluation unit which can be coupled to the measuring cell. Thereby, the achievable measurement precision is increased and at the same time an explosion protection is achieved.

[0022] The above basic object is likewise achieved by a computer program product according to the application. The computer program product is designed to receive and process a measurement signal of a microphone. The computer program product is likewise designed to determine a concentration of oxygen impurities in a hydrogen-containing mixed gas. The determination of the oxygen impurity concentration is based on a plurality of factors, including the measurement signal transmitted by the microphone to the computer program product. According to the application, the computer program product is configured to carry out at least one embodiment of the above-described method. The features of the respective method and the associated electrolysis device can thus be applied individually or in combination to the computer program product according to the application. The computer program product can be configured to be executable in an evaluation unit of the electrolysis device, wherein the evaluation unit can belong to a control unit of the electrolysis device. Furthermore, the computer program product can be designed in one piece, i.e. designed to be executable on a single hardware platform. Alternatively, the computer program product can be designed modularly, i.e. comprise a plurality of subprograms which are executable on separate hardware platforms and are connected to each other by a communication data connection. The subprograms thus work together to achieve the functionality of the computer program product. The computer program product can for example be designed to be executable on a memory programmable controller (SPS for short), a host computer or a computer cloud. The computer program product claimed is able to identify the presence of impurities quickly and reliably with reduced computing power requirements. The computer program product can also have a data interface via which a warning can be output to a user and / or a control program of the electrolysis device.

[0023] The above object is also achieved by the use of a measuring device according to the application. The measuring device is configured to determine the speed of sound in a mixed gas containing hydrogen, in particular molecular hydrogen, and impurities, in particular oxygen impurities and / or nitrogen impurities. According to the application, the measuring device is used in an electrolysis device. In particular, the measuring device is used to determine the concentration of oxygen impurities in a hydrogen fluid in which the products of the electrolysis reaction carried out are discharged during operation of the electrolysis device. The features of the measuring device and the electrolysis device as described above can thus be transferred individually or in combination to the use according to the application. The measuring device suitable for measuring the speed of sound in a mixed gas is available in a simple manner and is suitable for a plurality of mixed gases. The use claimed advantageously allows, for example, the use of an existing measuring device which is provided, for example, as laboratory equipment, for use in an industrial electrolysis device. The electrolysis device can for example have a hydrogen yield of at least 0.25 Nm 3 / h, in particular at least 10 Nm 3 / h, preferably at least 100 Nm 3 / h, particularly preferably at least 1000 Nm 3 / h. The unit Nm 3 / h here denotes normal cubic meters per hour.

[0024] Furthermore, the object set out at the outset is achieved by means of a simulation program product according to the application. The simulation program product contains instructions which enable a computer, when executed, to simulate the operating behavior of an electrolysis device. Accordingly, the simulation program product is designed to reproduce the operating behavior of an electrolysis device. According to the application, the electrolysis device is designed in accordance with one of the above-mentioned embodiments. The simulation program product is suitable for a run-parallel and / or a prior simulation of the operating behavior of a corresponding electrolysis device. Likewise, the simulation program product is suitable for reproducing a previous operating state of an electrolysis device on the basis of historical operating data.

[0025] The simulation program product can be provided with a data interface via which predetermined operating conditions for carrying out the simulation can be set. The predetermined operating conditions can be set by a user, another simulation-oriented computer program and / or suitable sensor technology. The predetermined operating conditions can include the existing molecular hydrogen and molecular oxygen yields, the flow behavior of the hydrogen fluid, i.e. the mixed gas containing the generated molecular hydrogen, and / or the existing concentration of oxygen impurities in the hydrogen fluid. Furthermore, the temperature, the pressure, the density, the speed of sound present therein of the mixed gas, control instructions to the sound emitter, and / or an indication of the damage of the separation membrane of the electrolysis device can belong to the presettable operating conditions.

[0026] The simulation program product can comprise a physical module which can have a digital image of the electrolysis device and / or a corresponding calculation model. The physical module is suitable for determining at least one presettable parameter in the electrolysis device which depends on the presettable operating conditions on the basis of the presettable operating conditions. Among the presettable parameters to be determined, for example, the measurement signal resulting from the simulationally exciting a resonance in the measurement chamber can be included. The physical effects on which the corresponding action chains are based can essentially be implemented algebraically in the electrolysis device. In particular, since the wall thickness of the measurement chamber profile body ensures the homogenization of the temperature distribution in the measurement chamber, the influence of the impurities on the speed of sound in the mixed gas can essentially be calculated idealistically. During the simulation of the operating behavior, interference effects and / or transient effects can be neglected without limiting the realism. The application is based on the surprising finding that the measurement chamber used and the thermodynamic effects occurring therein are particularly suitable for simulation.

[0027] The analog measurement signal may, for example, be an analog microphone measurement signal. Alternatively or additionally, the speed of sound in the mixed gas of the substance sample located in the analog measurement chamber thus determined can also be used as a measurement signal. It can thus be verified, for example, whether the determined impurity concentration, i.e. the concentration of oxygen impurities and / or nitrogen impurities, is likely to be real or whether at least one component of the electrolysis device, in particular the microphone, the temperature measurer and / or the pressure sensor in the measurement chamber, is likely to have been damaged. To this end, the analog program product may, for example, be connected to a database containing historical measurement data. A sudden increase in the impurity concentration can typically be caused by a sensor fault, while a sustained increase can be caused by degradation of the separation membrane. The analog program product can contain or be coupled to an artificial intelligence to carry out such plausibility checks.

[0028] Furthermore, the analog program product can contain a data interface via which preset parameters can be output as analog results. The analog results can be output to a user and / or to other analog-oriented computer programs via the data interface. Alternatively or additionally, the analog results can be output to a control program of the electrolysis device in order to issue control commands by which the electrolysis device identified as being in an abnormal operating state is converted into a safe operating state. The analog program product according to the application can constitute a so-called digital twin, as described, for example, in document US 2017 / 286572 A1. The disclosure of US 2017 / 286572 A1 is incorporated by reference into the present application. The electrolysis device, in particular its measurers, on the basis of which the analog program product according to the application is based, can be simulated in a surprisingly simple manner. At the same time, the analog program product provides a higher degree of realism here. Overall, the analog program product of the application is suitable for monitoring the operation of the respective electrolysis device. This monitoring can be carried out essentially in real time, which allows particularly fast-responding and thus safe operation of the electrolysis device. Thereby, the technical useful life of the wear-prone components in the simulated electrolysis device can be more fully utilized, which allows less interrupted and at the same time economic operation. The analog program product can be suitable for determining when a critical concentration of oxygen impurities in the hydrogen fluid is to be expected by pre-simulating the operation of the electrolysis device. The maintenance operation of the electrolysis device can thus be scheduled in advance of the approach to the critical concentration. By means of the analog program product of the application, particularly advantageous operation of the respective electrolysis device can generally be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0029] The application will be explained in detail below with the aid of various embodiments in conjunction with the drawings. The various drawings are to be understood complementarily, i.e. identical reference signs in different drawings have the same technical meaning. The features of the various embodiments can also be combined with one another. Furthermore, the features of the embodiments shown in the drawings can be combined with the features outlined above. Specifically shown:

[0030] Figure 1schematic diagram showing an embodiment of the electrolysis device for which protection is sought;

[0031] Figure 2 longitudinal sectional view of a measuring device showing an embodiment of the electrolysis device for which protection is sought. DETAILED DESCRIPTION

[0032] In Figure 1 The construction of an embodiment of the electrolysis device 10 for which protection is sought is shown in schematic form in the figure. The electrolysis device 10 comprises an electrolysis cell 39 in which, during operation of the electrolysis device 10, an electrolysis reaction takes place from which molecular hydrogen 13 and molecular oxygen 15 are obtained from water. The electrolysis device 10 further comprises a separation membrane 16 which is arranged in the electrolysis cell 39. The obtained molecular hydrogen 13 is conducted from the electrolysis cell 39 through a first pipe 12, and the molecular oxygen 15 is conducted through a second pipe 14. As a result, a hydrogen fluid 17 is present in the first pipe 12, and an oxygen fluid 19 is present in the second pipe 14. When the separation membrane 16 suffers damage and / or wear, oxygen enters the first pipe 12, so that the hydrogen fluid 17 forms a mixed gas 11 consisting of molecular hydrogen 13 and oxygen impurities 18. When the oxygen impurities 18 in the mixed gas 11 reach a sufficient concentration, the mixed gas will become a flammable gas. In addition to the oxygen impurities 18, nitrogen impurities, which are not shown in detail in the figure, can also be present in the hydrogen fluid 17.

[0033] The measuring device 20 is hydraulically connected to the first pipe 12, so that a substance sample 22 is continuously, i.e. in connection with the operation, introduced into the measuring device 20 from the mixed gas 11. The substance sample 22 is representative of the hydrogen fluid 17 with oxygen impurities 18 in the first pipe 12, i.e. of the same mixed gas 11, in terms of its composition of molecular hydrogen 13 and oxygen impurities 18. The measuring device 20 is connected to the first pipe 12 by means of a supply pipe 21 and a discharge pipe 23, through which the substance sample 22 flows. The measuring device 20 is connected to an evaluation unit 40, which in turn belongs to a control unit 50 of the electrolysis device 10. On the evaluation unit 40, a computer program product 45 is stored executable, which is designed to detect the concentration 32 of oxygen impurities 18 in the substance sample 22, and thus also the oxygen impurity concentration in the hydrogen fluid 17. The computer program product 45 is adapted to receive and evaluate a measurement signal 27 from the measuring device 20. The evaluation unit 40 is connected to the control unit 50 by means of a data interface 44, so that the electrolysis device 10 can be controlled in response to the detected concentration 32 of oxygen impurities 18. To this end, the control unit 50 is equipped with a frequency generator and a control program 55 stored executable thereon, which is designed to generate and output control instructions 29. Furthermore, on the evaluation unit 40, a simulation program product 60 is stored executable, which is designed as a digital twin of the electrolysis device 10.

[0034] A method 100 for detecting the concentration 32 of oxygen impurities 18 in hydrogen fluid 17 can be implemented on the electrolysis apparatus 10. Method 100 begins with a first step 110, in which the electrolysis apparatus 10 is operated, such as... Figure 1 As shown, at least hydrogen fluid 17 from electrolyzer 39 is present. Method 100 also includes a second step 120, in which the velocity of sound 42 in the mixed gas 11 supplied to the measuring device 20 as a material sample 22 is detected by the measuring device 20. The detected velocity of sound 42 is compared with a reference velocity of sound 41 by a computer program product 40 in the second step 120. Furthermore, method 100 includes a third step 130, which is also performed in the computer program product 45. In the third step 130, the concentration 32 of oxygen impurities 18 in the mixed gas 11 is determined. This is based on the comparison performed in the second step 120. Also in the third step 130, a warning 48 is output when the determined concentration 32 of oxygen impurities 18 numerically exceeds a preset threshold value 34.

[0035] according to Figure 1 The measuring device 20 of the illustrated embodiment is in Figure 2 The image is schematically shown in longitudinal section. For example... Figure 1 As shown, the measuring device 20 can be used in the electrolysis apparatus 10. The measuring device 20 is designed, especially in applications such as... Figure 1 In the method 100 shown for detecting the concentration 32 of oxygen impurities 18 in hydrogen fluid 17, a second step 120 is performed. The measuring device 20 includes a measuring chamber 30 through which a material sample 22 flows during operation. The material sample 22 is input through a supply pipe 21 and output through an outlet pipe 23. The measuring chamber 30 is permeated by the material sample 22 along the flow direction 31. Furthermore, the measuring chamber 30 has a profile body 37 that extends substantially along a main axis 25. The profile body 37 has a wall thickness 35 on its outer surface, such that the profile body 37 acts as a heat conductor and thermal buffer. The profile body 37 is made of a metallic material, such as an aluminum alloy, thereby presenting a substantially uniform temperature distribution in the material sample 22 within the measuring chamber 30. The profile body 37 and the measuring chamber 30 are closedly formed at their end faces 28.

[0036] An acoustic emitter 24 is disposed on one of the end faces 28, and the acoustic emitter is controlled by the evaluation unit 40 via control command 29. The acoustic emitter 24 is designed to be tunable, so that sound waves with a preset frequency or wavelength can be generated in the measurement chamber 30 and thus in the material sample 22. In particular, harmonic vibrations 49 can be generated, wherein... Figure 2 The first harmonic vibration is illustrated exemplarily in the diagram. Figure 2The sound pressure of the harmonic oscillation 49 is shown in the middle. Along the main axis 15, a microphone 26 is arranged at the middle section 33 of the wall of the measuring chamber 30. This microphone 26 is suitable for detecting the harmonic oscillation 49. By positioning the microphone 26 at the middle section 33, it is suitable for detecting the amplitude maximum of the even harmonic oscillation 49. For this purpose, the microphone 26 is connected to the evaluation unit 40, so that the measuring signal 27 can be transmitted to the evaluation unit 40. By means of a corresponding frequency scan of the sound emitter 24, it is possible to identify at which excitation frequency the sound emitter 24 generates an even harmonic oscillation 49 in the measuring chamber 30. By means of the microphone 26, it is also possible to determine the existing resonance frequency of the harmonic oscillation 49. There is a physical correlation between the existing resonance frequency in the substance sample 22 and the speed of sound 42 therein. In a second step 120, the existing speed of sound 42 is compared with the reference speed of sound 43 and a speed of sound difference 43 is determined. The reference speed of sound 41 corresponds to the speed of sound in the hydrogen fluid 17 without the oxygen impurities 18. The speed of sound difference 43 represents a measure of the concentration of the oxygen impurities 18. The determination of the concentration 32 of the oxygen impurities 18 takes place in a third step 130, which is not shown in detail.

[0037] The measuring device 20 is provided with a temperature measuring device 36 and a pressure sensor 38 at the wall of the measuring chamber 30, which are designed to detect the current temperature and pressure in the measuring chamber 30. The temperature measuring device 36 and the pressure sensor 38 are coupled to the evaluation unit 40 and are suitable for transmitting the respective measured values as measuring signals 27 to the evaluation unit 40. On the basis of the measuring signals 27 from the temperature measuring device 36 and / or the pressure sensor 38, the determination of the speed of sound 42 in the substance sample 22 is temperature- and / or pressure-compensated. The respective pressure and / or temperature compensation is provided by means of the computer program product 45 on the evaluation unit 40.

[0038] When, for example, in the case of a hydrogen fluid 17, the speed of sound 42 is determined in the substance sample 22, the substance sample 22 is preferably a hydrogen fluid 17, which is preferably contained in a tank 10. The hydrogen fluid 17 is preferably a hydrogen gas, which is preferably used as a fuel in a fuel cell. Figure 1The evaluation unit 40 outputs a warning 48 to the user and / or to the data interface 44 when the concentration 32 of the oxygen impurities 18 is determined in the third step 130 and exceeds a predefinable limit value 34. The evaluation unit 40 belongs to a control unit 50 of the electrolysis device 10 and is connected to the control unit via the data interface 44. A control program 55 is stored on the control unit 50, by means of which control instructions 29 (not shown in detail) for predefining the operating mode of the electrolysis device 10 can be output. A database 52 is also provided in the control unit 50, in which the concentration 32 of the oxygen impurities 18 obtained from historical measurement data is analytically provided. The historical measurement data can be collected on the electrolysis device 10 itself and / or on identical electrolysis devices. The database 52 can be evaluated analytically by means of a digital twin 60 of the electrolysis device 10. In this way, when the concentration 32 of the oxygen impurities 18 rises, it can be determined what the cause is. Furthermore, the electrolysis device 10 is mapped in the digital twin 60, which is executed in real time on the evaluation unit 40. The digital twin 60 is designed to identify defective components of the electrolysis device 10, in particular a damaged or worn-out separation membrane 16 as shown. Figure 1 the concentration 32 of the oxygen impurities 18 is determined in the third step 130 and exceeds a predefinable limit value 34. The evaluation unit 40 belongs to a control unit 50 of the electrolysis device 10 and is connected to the control unit via the data interface 44. A control program 55 is stored on the control unit 50, by means of which control instructions 29 (not shown in detail) for predefining the operating mode of the electrolysis device 10 can be output. A database 52 is also provided in the control unit 50, in which the concentration 32 of the oxygen impurities 18 obtained from historical measurement data is analytically provided. The historical measurement data can be collected on the electrolysis device 10 itself and / or on identical electrolysis devices. The database 52 can be evaluated analytically by means of a digital twin 60 of the electrolysis device 10. In this way, when the concentration 32 of the oxygen impurities 18 rises, it can be determined what the cause is. Furthermore, the electrolysis device 10 is mapped in the digital twin 60, which is executed in real time on the evaluation unit 40. The digital twin 60 is designed to identify defective components of the electrolysis device 10, in particular a damaged or worn-out separation membrane 16 as shown. Figure 1 the concentration

Claims

1. An electrolysis apparatus (10) comprising a separation membrane (16) for generating hydrogen (13) and oxygen (15) from water and a first conduit (12) for extracting hydrogen (15) in a hydrogen fluid (17), wherein, A measuring device (20) for detecting impurities (18) in the hydrogen fluid (17) is arranged in the region of the first pipe (12), wherein the impurities (18) are oxygen impurities, characterized in that the measuring device (20) is designed to detect acoustic characteristic parameters in the hydrogen fluid (17) to detect the presence of the oxygen impurities in the hydrogen fluid (17).

2. The electrolysis apparatus (10) according to claim 1, characterized in that, The acoustic characteristic parameter is the velocity of sound (42) in the hydrogen fluid (17), and / or the measuring device (20) is designed as a sound velocity measuring device.

3. The electrolysis apparatus (10) according to claim 1 or 2, characterized in that, The measuring instrument (20) is designed to excite and detect acoustic resonances in a material sample (22) taken from the hydrogen fluid (17).

4. The electrolysis apparatus (10) according to any one of claims 1 to 3, characterized in that, The measuring instrument (20) has a microphone (26) which is arranged in the middle section (33) along the main axis (15) of the measuring chamber (20).

5. The electrolysis apparatus (10) according to claim 4, characterized in that, The measuring instrument (20) has at least one additional microphone (26) arranged in the measuring chamber (30).

6. The electrolysis apparatus (10) according to any one of claims 1 to 5, characterized in that, The measuring device (20) is equipped with an evaluation unit (40) designed to determine the concentration (32) of the impurity (18) in the hydrogen fluid (17).

7. The electrolysis apparatus (10) according to claim 6, characterized in that, The evaluation unit (40) has a bandpass filter for evaluating the measurement signal (27) from the microphone (26).

8. The electrolysis apparatus (10) according to any one of claims 1 to 7, characterized in that, The measuring device (20) is equipped with a temperature measuring device (36).

9. The electrolysis apparatus (10) according to any one of claims 1 to 8, characterized in that, The measuring device (20) is equipped with a pressure sensor (38).

10. A method (100) for detecting the concentration (32) of impurities (18) in hydrogen (13) in hydrogen fluid (17) in an electrolysis apparatus (10), comprising the following steps: a) Operate the electrolysis unit (10) and introduce a mixed gas (11) containing hydrogen (13) and impurities (18) into the first pipe (12); b) Detect the speed of sound (42) in the gas mixture (11) and compare it with a reference speed of sound (43); c) Determine the concentration of impurity (18) in the mixed gas (44) based on the comparison in step b), and output a warning (48) when the determined concentration (32) of the impurity (18) exceeds a preset boundary value (34), wherein the impurity (18) is an oxygen impurity.

11. The method (100) according to claim 10, characterized in that, The method (100) is performed on the electrolysis apparatus (10) according to any one of claims 1 to 9.

12. The method (100) according to claim 10 or 11, characterized in that, In step b), the velocity of the sound (42) is determined taking into account the detected temperature and / or detected pressure of the mixed gas (11).

13. A computer program product (45) for receiving and evaluating measurement signals (27) from a microphone (26) designed to determine the concentration (32) of impurities (18) in a gas mixture (11) containing hydrogen (13), characterized in that, The computer program product (45) includes instructions that cause the evaluation unit (40) of the measuring instrument (20) of the electrolysis apparatus (10) according to any one of claims 1 to 9 to perform the method (100) according to any one of claims 10 to 12.

14. An application of a measuring instrument (20) designed to determine the velocity (42) of sound in a mixture of gas (11) containing hydrogen (13) and impurities (18), characterized in that, The measuring device (20) is installed in the electrolysis apparatus (10) according to any one of claims 1 to 9.

15. A simulation program product (60) comprising instructions that, when executed by a computer, cause the computer to simulate the operating behavior of the electrolysis apparatus (10) according to any one of claims 1 to 9.

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