System for measuring concentration of at least one chemical component in flowing fluid

Abstract

The invention relates to a system (100) for measuring the concentration of at least one chemical component in a flowing fluid (200), comprising: a light source (10) configured to emit an excitation light beam (11); a measurement cell (20) comprising a fluid conduit adapted to flow the fluid and portholes (23, 24), one of which is arranged to receive the excitation light beam and the other arranged to transmit a first light beam (12) formed by the excitation light beam scattered and / or transmitted through the fluid; optical means (30) positioned to reflect the first light beam and to form a reflected light beam (13) towards the fluid, the second light beam (14) being formed by scattering and / or transmission of the reflected light beam in the fluid; a Raman spectrometer (45) configured to receive the second light beam and generate a spectral measurement; a calculation unit (50) adapted to measure the pressure of the fluid; a computing unit (60) programmed to determine a concentration of the at least one chemical component based on the spectral measurements and the fluid pressure.

Description

System for measuring the concentration of at least one chemical component in a flowing fluid. Technical Field

[0001] This invention generally relates to the measurement of concentrations in fluids (particularly gases).

[0002] More specifically, the present invention relates to a system for measuring the concentration of at least one chemical component in a flowing fluid, the system being used in an electrochemical generator system of the type of fuel cell or electrolyzer.

[0003] Particularly advantageously, the present invention can be applied to measuring gases entering or leaving such electrochemical generator systems. Background Technology

[0004] Fuel cell-type electrochemical generator systems can produce electricity through the oxidation of fuel, such as hydrogen. The result is the generation of electricity from hydrogen.

[0005] Conversely, electrochemical generator systems of the electrolyzer type can generate chemical components from electrical energy. For example, electrochemical generator systems including water electrolysis-based electrolyzers can produce hydrogen and oxygen using electrical energy. The result is the production of hydrogen.

[0006] In order to characterize the operating state of such electrochemical generator systems and thus assess their performance in real time, it is of practical significance to measure the concentrations of different chemical elements entering and / or leaving the electrochemical generator system.

[0007] The solution involves extracting a portion of the gas at the inlet or outlet of the electrochemical generator system and analyzing its composition based on destructive or non-destructive treatment of the extracted sample. In practice, a portion of the fluid is directed to a pressure-controlled measurement system. However, this extraction method can disrupt the operation of the electrochemical generator system.

[0008] Furthermore, the pressure of the flowing fluid changes during the operation of the electrochemical generator system, especially when the system switches from a quiescent to an active state. For example, generating current using an electrochemical generator system is accompanied by higher hydrogen consumption and a large amount of water production, which leads to a decrease in pressure at the outlet of the electrochemical generator system. Summary of the Invention

[0009] Against this background, the present invention relates to a system for measuring the concentration of at least one chemical component in a flowing fluid in an electrochemical generator system, the measuring system comprising: - a light source configured to emit an excitation beam; - a measuring cell comprising a fluid conduit suitable for the flowing fluid to flow therein, the measuring cell comprising two watertight ports arranged laterally on the fluid conduit and positioned opposite each other transversely to the principal optical axis of the fluid conduit, one of the two ports being arranged to receive the excitation beam and the other being arranged to transmit a first beam formed by scattering and / or transmission of a reflected beam through the flowing fluid; - at least partially reflective optics positioned to reflect the first beam and form a reflected beam toward the flowing fluid, one of the two ports being arranged to receive the excitation beam and the other being arranged to transmit a second beam formed by scattering and / or transmission of the reflected beam through the flowing fluid; - a Raman spectrometer configured to receive the second beam and generate spectral measurements based on the second beam; - a pressure sensor suitable for measuring the pressure of the flowing fluid; - a computing unit programmed to determine the concentration of at least one chemical component based on the spectral measurements and the pressure of the flowing fluid.

[0010] Therefore, the measuring cell according to the present invention enables the measurement of the concentration of different chemical elements without producing flow deviation.

[0011] Furthermore, due to this invention, the inherent changes in the pressure of the flowing fluid are taken into account during concentration measurement. In other words, the signal from the spectrometer is corrected for pressure changes. Therefore, concentration measurements independent of the flowing fluid pressure can be obtained.

[0012] Other non-limiting and advantageous features of the system according to the invention (which may be used individually or in any combination of all technically feasible options) are as follows: - The pressure sensor is arranged inside the fluid conduit; - The pressure sensor is positioned less than 10 cm from one of the portholes; - The pressure sensor is a pressure gauge or a networked pressure sensor; - The pressure sensor is adapted to measure pressures below 6 bar; - The pressure sensor is adapted to repeatedly measure the pressure of the flowing fluid at a frequency between 0.1 and 10 Hz; - At least one chemical component is selected from water, molecular nitrogen, molecular hydrogen, or molecular oxygen; - The calculation unit is programmed to calculate the concentration of at least one chemical component based on the ratio of the spectral measurement to the pressure of the flowing fluid; - At least one chemical component is also present in ambient air, and the calculation unit is programmed to apply a correction to the spectral measurement based on the reference spectral measurement generated by the spectrometer when a reference flowing fluid without the chemical component flows in the fluid conduit.

[0013] The present invention also proposes a method for measuring the concentration of at least one chemical component in a flowing fluid, comprising the following steps: - emitting an excitation beam; - causing the excitation beam to scatter and / or transmit through the flowing fluid to form a first beam; - reflecting the first beam into a reflected beam directed toward the flowing fluid, and causing the reflected beam to scatter and / or transmit through the flowing fluid to form a second beam; - generating spectral measurements based on the second beam using a Raman spectrometer; - measuring the pressure of the flowing fluid; - calculating the concentration of at least one chemical component based on the spectral measurements and the pressure of the flowing fluid.

[0014] Obviously, the different features, alternatives and embodiments of the present invention can be associated with each other in various combinations, as long as they are not mutually exclusive or mutually exclusive. Attached Figure Description

[0015] The following description, taken in conjunction with the accompanying drawings which are given by way of non-limiting example, will help to provide a full understanding of the structure of the invention and its implementation.

[0016] In the accompanying drawings: Figure 1 is a schematic diagram of the measurement system according to the present invention; Figure 2 is a block diagram of the sequence of steps for measuring the concentration of chemical components in a flowing fluid; Figure 3 is a graphical representation of two signals from the spectrometer of the system of Figure 1; Figure 4 is a graphical representation of the spectrum obtained by the spectrometer of the system of Figure 1; and Figure 5 is a graphical representation of the concentrations (in percentage) of two chemical components in the flowing fluid measured over time by the system of Figure 1. Detailed Implementation

[0017] Figure 1 shows a schematic diagram of a measurement system 100, which is particularly suitable for measuring the concentration of chemical components (i.e., chemical elements, typically molecules) present in a flowing fluid 200. The flowing fluid 200 may be in gaseous or liquid form. As will be understood below, the term "flowing" as used herein means that the flowing fluid 200 is in a flowing state at the time of measurement. The flowing fluid 200 is hereinafter simply referred to as fluid 200.

[0018] As shown in Figure 1, the measurement system 100 here includes a light source 10, a measurement cell 20, an optical device 30, a spectrometer 45, a pressure sensor 50, and a computing unit 60.

[0019] The measuring system 100 is particularly suitable for measuring fluid 200 from or supplied to an electrochemical generator system 301. The electrochemical generator system 301 can be used as an electrolyzer. For example, the electrochemical generator system 301 is an electrolyzer for producing hydrogen. The electrochemical generator system 301 then consumes electricity to produce hydrogen.

[0020] In another application, the electrochemical generator system 301 is used to generate electricity. In this case, the electrochemical generator system 301 consumes fuel (e.g., hydrogen) to produce electricity.

[0021] The spectrometer 45 is particularly suitable for measuring the concentration of at least one chemical component in a fluid 200, which is selected from water (such as water vapor), molecular nitrogen, molecular hydrogen, and molecular oxygen.

[0022] Therefore, the spectrometer 45 is preferably a Raman spectrometer.

[0023] Here, as shown in Figure 1, the light source 10 and the spectrometer 45 together form part of the spectral measurement device 40. In the example of Figure 1, the spectral measurement device 40 is positioned facing the measurement cell 20. Conventionally, the light source 10 and the spectrometer 45 can be placed away from the measurement cell 20, and the light beam can be transmitted via fiber optic cable.

[0024] The light source 10 is preferably a high-intensity laser. Here, the light source 10 is, for example, a laser with a power of 1.5W that emits a monochromatic beam with a wavelength of 532nm. The light source 10 is a high-power light source to obtain a Raman signal with sufficiently high intensity, thereby achieving an integration time compatible with real-time monitoring, for example, at a frequency between 0.1Hz and 10Hz. Alternatively, the excitation beam can be generated by any light source suitable for Raman spectroscopy analysis. For example, the light source 10 is controlled by a spectrometer 45.

[0025] The measuring tank 20 includes an inlet opening 21, an outlet opening 22, a first porthole 23, a second porthole 24, and a housing 25. Portholes 23 and 24 are located at lateral openings in the housing 25. Here, the housing 25, along with portholes 23 and 24, defines a fluid conduit for the flow of fluid 200. Therefore, this fluid conduit extends from the inlet opening 21 of the measuring tank 20 to the outlet opening 22.

[0026] As shown in Figure 1, the inlet opening 21 is connected to a first delivery conduit 302 for fluid 200, which itself is connected to the electrochemical generator system 301. This first delivery conduit 302 then fluidly communicates the electrochemical generator system 301 with the measuring cell 20. The outlet opening 22 is connected to a second delivery conduit 303 for fluid 200, which itself is connected to a storage tank 304 designed to collect fluid 200. Therefore, this second delivery conduit 304 fluidly communicates the measuring cell 20 with the storage tank 304.

[0027] Therefore, as shown in Figure 1, the measuring cell 20 is capable of measuring the outflowing fluid 200, i.e., the fluid generated by the electrochemical generator system 301. As shown in Figure 1, the measuring cell 20 is, for example, connected to the outlet of an electrolyzer for generating hydrogen.

[0028] Conversely, the outlet opening can be connected to a flow delivery conduit at the inlet of the electrochemical generator system. In this case, the measuring cell can measure the fluid entering the electrochemical generator system. The measuring cell can, for example, be connected to the inlet of a hydrogen fuel cell-type electrochemical generator system used for generating electricity from hydrogen.

[0029] In order to prevent any pressure or flow rate changes in the fluid 200, the cross-sections of the inlet opening 21, the outlet opening 22, and the housing 25 are each higher than or equal to the cross-sections of the conduits 302 and 303 used to transport the fluid 200.

[0030] Portholes 23 and 24 are watertight, which means that fluid 200 cannot escape from the fluid conduit through the side openings.

[0031] Here, the measuring cell 20 includes gaskets (not shown) placed between the housing 25 and the portholes 23, 24. For example, the measuring unit 20 includes one gasket for each porthole 23, 24.

[0032] These gaskets are made, for example, of fluoroelastomer materials (commonly known as FKM or Viton).

[0033] The term "porthole" as understood here refers to a glass panel of any shape that provides an optical pathway to the interior of housing 25 (i.e., the interior of the fluid conduit).

[0034] Therefore, each porthole 23, 24 comprises a glass pane. These glass panes are preferably made of borosilicate glass, aluminosilicate glass, or alkali aluminosilicate glass, for example, BK7 glass or Gorilla Glass. Preferably, the side of the glass pane in contact with the fluid 200 (i.e., the side facing the interior of the housing 25) has no surface coating. The composition and arrangement of the glass panes prevent the release of any gases that might affect the measurement or contaminate the fluid 200.

[0035] Referring to the flow direction of fluid 200, two portholes 23 and 24 are laterally disposed on the shell 25, located downstream of inlet opening 21 and upstream of outlet opening 22. The two portholes 23 and 24 are arranged opposite each other. For example, when the shell 25 is circular, the two portholes 23 and 24 are arranged with their diameters opposite each other. In another example, when the shell 25 has a square or rectangular cross-section, the two portholes 23 and 24 are arranged on two opposite faces of the shell 25. In any case, the arrangement of the two portholes 23 and 24 allows fluid 200 to flow between the portholes 23 and 24.

[0036] As shown in Figure 1, the measuring cell 20 is arranged such that the two portholes 23, 24 are aligned along the principal optical axis OA, which is transverse to the flow direction of the fluid 200. This means that the portholes 23, 24, and more specifically their glass plates, intersect the principal optical axis OA. In the example shown in Figure 1, the principal optical axis OA is more specifically perpendicular to the flow direction of the fluid 200.

[0037] The two portholes 23 and 24, more specifically their glass panes, are configured to transmit the excitation beam 11. Preferably, as shown in FIG1, the excitation beam 11 propagates along the main illumination axis aligned with (i.e., parallel to) the main optical axis OA.

[0038] System 1 also includes an optical element 70 arranged in the path of the excitation beam 11, located between the light source 10 and the first porthole 23. The optical element 70 is configured to focus the excitation beam 11 into the fluid 200 between the two portholes 23, 24 of the measuring cell 20. The optical element 70 is, for example, a lens or objective lens.

[0039] Optical device 30 is at least partially reflective. Preferably, optical device 30 is a concave mirror. Device 30 includes, for example, a spherical mirror, which is arranged such that its center of curvature is located on the principal optical axis OA and is equidistant from the two portholes 23, 24.

[0040] As shown in Figure 1, the optical device 30 is arranged to face the second porthole 24. Therefore, the optical device 30 allows light from the second porthole 24 to be reflected back into the second porthole 24. Thus, the optical device 30 is positioned opposite the light source 10 relative to the measuring cell 20.

[0041] Therefore, the measuring cell 20 is of the two-way type because, when used in conjunction with the optics 30, it can doubly excite the fluid 200. In fact, the excitation beam 11 passes through the measuring cell 20 and is subsequently refocused into the fluid 200, thus achieving dual excitation. Furthermore, this optical configuration has the advantage of collecting not only light emitted toward the spectrometer 45, but also light emitted toward the optics 30 and reflected back to the spectrometer 45, thereby doubling the effective stereo collection angle. Therefore, the term "two-way" relates to the round-trip journey of the beam within the measuring cell 20. However, the fluid 200 only passes through the measuring cell 20 once in the flow direction, and the flow is uninterrupted.

[0042] Pressure sensor 50 is suitable for measuring the pressure of fluid 200. Pressure sensor 50 is particularly suitable for measuring the pressure of fluid 200 in measuring tank 20, i.e., the pressure in the fluid conduit. The cross-sections of delivery conduits 302, 303 and housing 25 are selected to avoid pressure variations, so that the pressure of fluid 200 can actually be measured in delivery conduits 302, 303 or in the fluid conduit. Therefore, pressure sensor 50 can be placed in these locations.

[0043] However, the pressure sensor 50 is preferably placed in the measuring cell 20, i.e., inside the fluid conduit. For example, as shown in FIG1, it is arranged to rest against the housing 25, and more specifically, against the surface of the housing 25 that is in contact with the fluid 200.

[0044] More preferably, the pressure sensor 50 is located less than 10 centimeters from the portholes 23 and 24.

[0045] The pressure sensor 50 is preferably a networked pressure sensor, which simplifies its connection to the computing unit 60. Alternatively, the pressure sensor can be a pressure gauge.

[0046] Pressure sensor 50 is suitable for measuring pressures between 0 and 6 bar. Preferably, pressure sensor 50 is suitable for measuring the pressure of fluid 200 at frequencies between 0.1 Hz and 10 Hz.

[0047] The computing unit 60 includes at least one memory and at least one processor. The computing unit 60 also includes an interface that enables it to receive information from the spectrometer 45 and the pressure sensor 50. Here, the computing unit 60 acts as a synchronization box and triggers data acquisition from the spectrometer 45 and the pressure sensor 50, meaning that the computing unit 60 controls data acquisition.

[0048] The memory of the computing unit 60 is a computer-readable recording medium containing instructions that, when executed by a processor, are capable of determining the concentration of at least one chemical component in the fluid 200 based on data provided by the spectrometer 45 and the pressure sensor 50.

[0049] The measuring system 100 enables a method for measuring the concentration of at least one chemical component in fluid 200. This method is described with reference to Figures 3 through 5. In these figures, fluid 200 exemplarily contains two components: molecular nitrogen and molecular hydrogen. For illustration, the concentrations are preset: molecular nitrogen concentration is 20%, and molecular hydrogen concentration is 80%. Here we will verify that the method can indeed determine these preset concentrations by measurement. Similarly, in these figures, the pressure change of fluid 200 is controlled.

[0050] Preferably, the steps of the method are repeated to achieve real-time (i.e., continuous) tracking of concentration. However, these steps can also be performed only once to obtain a single measurement result at a specific time.

[0051] As shown in Figure 2, the method begins with the first step E1: the light source 10 emits an excitation beam 11.

[0052] The method continues to perform a second step E2, which includes causing the excitation beam 11 to be scattered and / or transmitted through the fluid 200 to form a first beam 12.

[0053] As shown in Figure 1, the second step E2 also includes the transmission of the excitation beam 11 through the first porthole 23 and the transmission of the first beam 12 through the second porthole 24. The first beam 12 passes through the second porthole 24 and is directed toward the optical device 30.

[0054] The method then includes a third step E3, in which the optics 30 reflects the first beam 12 as a reflected beam 13 toward the second porthole 24, thereby directing it toward the fluid 200. The optics 30 are positioned to receive the first beam 12. The reflective optics 30 are located outside the measuring pool 20. This arrangement avoids any interaction between the fluid 200 and the reflective coating (e.g., a metallic coating) of the optics 30, thereby preventing contamination of the fluid 200. The optics 30 are configured to focus the reflected beam 13 between the two portholes 23, 24 within the measuring pool 20, for example, at the midpoint between the two portholes 23, 24.

[0055] The method then includes a fourth step E4, which involves scattering and / or transmitting the reflected beam 13 through the fluid 200 to form a second beam 14.

[0056] As shown in Figure 1, the fourth step E4 further includes the reflected beam 13 being transmitted through the second porthole 24, and the second beam 14 being transmitted through the first porthole 23. The second beam 14 passes through the first porthole 23 and is directed toward the optical element 70. The optical element 70 enables the second beam 14 to be focused onto the spectrometer 45.

[0057] The method then includes a fifth step E5: generating at least one spectral measurement by spectrometer 45 based on the second beam 14. Here, spectrometer 45 generates one spectral measurement for each chemical component, that is, one measurement for molecular nitrogen and one for molecular hydrogen.

[0058] When step E5 is repeated over time (e.g., once per second), all the spectral measurements associated with the chemical component form a spectral signal associated with that chemical component. Each signal therefore contains several measurements. These measurements are generated, for example, at frequencies between 0.1 Hz and 1 Hz.

[0059] In the example of Figure 3, spectrometer 45 generates a first spectral signal 41 for molecular nitrogen and a second spectral signal 42 for molecular hydrogen. In this example, one spectral measurement is generated per second over a period of approximately one hour.

[0060] To perform these measurements, spectrometer 45 is configured to receive a second beam 14, which contains a Raman signal emitted by fluid 200. Spectrometer 45 is particularly well-suited for detecting the Raman signal emitted by fluid 200 in the second beam 14. The emission of the Raman signal is particularly facilitated by the excitation of fluid 200 by excitation beam 11 and reflected beam 13. Conventionally, spectrometer 45 includes a diffraction grating and a light sensor. It also includes a processing system capable of reading from the light sensor and thereby deriving spectral measurements.

[0061] Spectral measurements can be derived by summing the spectra of a subset of pixels in the same column of the optical sensor. For example, Figure 4 shows such a Raman spectrum. The Raman spectrum in Figure 4 shows the signal intensity I provided by the optical sensor as a function of the Raman shift Δω (unit: cm). -1 The intensity I is specifically shown as: corresponding to molecular nitrogen (N2), located at approximately 2301 cm⁻¹ -1 The first peak at [location missing], and the peak corresponding to molecular hydrogen (H2) at approximately 4100 cm⁻¹. -1 The second peak is located at [a certain point]. In Figure 4, the intensity is expressed in arbitrary units, such as corresponding to the photon count of the optical sensor. These spectra are generated, for example, at frequencies between 0.1 Hz and 1 Hz.

[0062] Typically, for each chemical component, the spectral measurement can correspond to the height of the relevant peak (e.g., the peak value), or the area of ​​the peak, i.e., the surface area of ​​the peak calculated for a predetermined shift range.

[0063] Each spectral measurement depends on the concentration of the chemical element in fluid 200, the pressure of fluid 200, and the power of the excitation beam 11 (the latter being known). Here, each spectral measurement is perfectly linearly related to the pressure of fluid 200.

[0064] Therefore, as shown in Figure 3, the first spectral signal 41 and the second spectral signal 42 change when the pressure of fluid 200 changes. In Figure 3, the pressure of fluid 200 changes in a controlled manner in a stepwise manner. Here, the pressure of fluid 200 increases or decreases by approximately ±0.1 bar, ±0.2 bar, or ±0.3 bar every 240 seconds. Therefore, spectral signals 41 and 42 also exhibit stepwise changes, which is particularly evident in high concentrations of molecular nitrogen. In Figure 3, the peaks visible between the steps correspond to transient conditions during pressure changes, where the pressure is briefly too high before stabilizing to the desired pressure.

[0065] To account for pressure changes, the method includes a sixth step, E6, in which the pressure of fluid 200 is measured using pressure sensor 50. As shown in Figure 2, the sixth step, E6, is performed in parallel with steps E1 to E5.

[0066] Pressure measurements are preferably performed simultaneously with the spectral measurements of each chemical component. Similarly, while generating one spectral measurement value per second, pressure is preferably measured once per second. Typically, the frequency of pressure measurements is, for example, between 0.1 Hz and 10 Hz.

[0067] Each pressure measurement performed by pressure sensor 50 provides a pressure value to calculation unit 60.

[0068] Subsequently, the calculation unit 60 is programmed to calculate the concentration of each chemical component during the seventh step E7 of the method. More specifically, it calculates a concentration for each spectral measurement.

[0069] The concentration calculation will now be described in detail for only one spectral measurement (and therefore only for one chemical component, referred to as the chemical component).

[0070] The calculation unit 60 first correlates the spectral measurement value with the pressure value, and more specifically, with the pressure value corresponding to the generation of the spectral measurement. Therefore, the spectral measurement and its associated pressure measurement occur simultaneously, and preferably synchronously. Here, this means, for example, that the time interval between the pressure measurement and the spectral measurement is less than 10 seconds, preferably less than 5 seconds, and more preferably less than 1 second.

[0071] Subsequently, step E7 involves converting the spectral measurements into the initial concentration of the chemical component using a calibration function.

[0072] The calibration function is pre-recorded in the memory of the computing unit 60. This calibration function represents an affine relationship between the spectral measurement value and the concentration of the chemical component. For example, it can be determined by measuring a standard fluid containing a known concentration of the chemical component. The calibration function is established for a predetermined and controlled reference pressure of the standard fluid. For example, the calibration function is established for a reference pressure of 1 to 2 bar. For instance, here the calibration function is established for a reference pressure of 1.5 bar.

[0073] The calibration function is specific to the chemical component. In fact, the computing unit 60 therefore stores one calibration function in memory for each chemical component.

[0074] The initial concentration of the chemical component currently depends on the pressure of fluid 200.

[0075] Step E7 then involves calculating the intermediate concentration of the chemical component by multiplying its initial concentration by a reference pressure (i.e., the pressure at which the calibration function is established). Thus, the initial concentration is multiplied, for example, by a factor of 1.5, which corresponds to the reference pressure mentioned in the example above. This calculation is optional when calibration is performed at a reference pressure of 1 bar, as it is equivalent to multiplying the initial concentration by 1.

[0076] Step E7 then includes calculating the chemical composition by dividing the intermediate concentration by the pressure value provided by pressure sensor 50 in step E6 (which is associated with the spectral measurement).

[0077] At this point, the concentration is independent of the pressure of fluid 200.

[0078] When the spectroscopic measurements were repeated over time, all concentrations could be represented graphically, presented separately for each chemical component. Figure 5 shows the concentration of fluid 200 (in percentage), with the time scale consistent with Figure 3. As can be seen from this figure, the concentration of fluid 200 does indeed remain stable despite the stepwise changes in pressure. The calculated molecular nitrogen concentration is approximately 20%, and the molecular hydrogen concentration is approximately 80% (the actual total chemical composition is exactly 100%). Therefore, the data shown in Figure 5 corresponds to the pressure-corrected data in Figure 3. The peaks visible in Figure 5 also correspond to transient conditions during pressure changes.

[0079] When spectral measurements are repeated over time, it can be noted that the same pressure value may be associated with multiple consecutive spectral measurements, especially when the frequency of spectral measurement generation is higher than the frequency of pressure measurement. However, as mentioned above, the frequency of spectral measurement generation is preferably equal to the frequency of pressure measurement.

[0080] When the chemical component of interest (i.e., the chemical whose concentration will be measured) is also present in the air, additional correction is required. Typically, this correction applies to molecular nitrogen. In practice, different light beams will interact with this component present in the air, which is insensitive to pressure changes in the fluid conduit.

[0081] Therefore, it is planned to obtain reference spectral measurements generated by spectrometer 45 when a fluid lacking this chemical component (in this case, molecular nitrogen) flows through a fluid conduit.

[0082] Before converting the spectral measurements to the initial concentration, the spectral measurements need to be corrected using a reference signal. In practice, the calculation unit 60 calculates the difference between the molecular nitrogen spectral measurement and the reference measurement, thereby deducting the contribution from ambient air. Subsequently, this difference is used to convert the initial concentration.

[0083] This invention is by no means limited to the embodiments described and illustrated, and those skilled in the art will know how to apply any variations according to this invention.

[0084] For example, pressure values ​​can certainly be expressed in units other than bar. Just ensure that pressure values ​​are expressed in the same unit throughout all calculations in step E7.

Claims

1. A system (100) for measuring the concentration of at least one chemical component in a flowing fluid (200) in an electrochemical generator system (301), said measuring system (100) comprising: - A light source (10) configured to emit an excitation beam (11); - A measuring cell (20) including a fluid conduit adapted for the flow of the fluid (200) therein, the measuring cell (20) including two watertight ports (23, 24) arranged laterally on the fluid conduit and positioned opposite each other on a transverse optical axis (OA) of the fluid conduit, one of the ports (23, 24) being arranged to receive the excitation beam (11) and the other being arranged to transmit a first beam (12) formed by the scattering and / or transmission of the excitation beam (11) through the flow of the fluid (200); - At least Partially reflective optical devices (30) are positioned to reflect the first light beam (12) and form a reflected light beam (13) toward the flowing fluid (200); one of the portholes (23, 24) is arranged to receive the reflected light beam (13), and the other is arranged to transmit a second light beam (14) formed by scattering and / or transmission of the reflected light beam (13) through the flowing fluid (200); a Raman spectrometer (45) is configured to receive the second light beam (14) and generate spectral measurements based on the second light beam (14); and a pressure sensor (50) is adapted to measure the pressure of the flowing fluid (200). - The calculation unit (60) is programmed to determine the concentration of the at least one chemical component based on the spectral measurements and the pressure of the flowing fluid (200).

2. The system (100) according to claim 1, wherein, The pressure sensor (50) is arranged inside the fluid conduit.

3. The system (100) according to claim 1 or 2, wherein, The pressure sensor (50) is positioned less than 10 centimeters from one of the portholes (23, 24).

4. The system (100) according to any one of claims 1 to 3, wherein, The pressure sensor (50) is a pressure gauge or a networked pressure sensor.

5. The system (100) according to any one of claims 1 to 4, wherein, The pressure sensor (50) is suitable for measuring pressures less than 6 bar.

6. The system (100) according to any one of claims 1 to 5, wherein, The pressure sensor (50) is adapted to repeatedly measure the pressure of the flowing fluid (200) at a frequency between 0.1 and 10 Hz.

7. The system (100) according to any one of claims 1 to 6, wherein, The at least one chemical component is selected from water, molecular nitrogen, molecular hydrogen, or molecular oxygen.

8. The system (100) according to any one of claims 1 to 7, wherein, The calculation unit (60) is programmed to calculate the concentration of the at least one chemical component based on the ratio of the spectral measurement value to the pressure of the flowing fluid (200).

9. The system (100) according to any one of claims 1 to 8, wherein, The at least one chemical component is also present in ambient air, and the computing unit (60) is programmed to apply correction to the spectral measurements based on reference spectral measurements generated by the spectrometer (45) when a reference flowing fluid (200) without the chemical component flows in the fluid conduit.

10. A method for measuring the concentration of at least one chemical component in a flowing fluid (200), comprising the following steps: - Emit an excitation beam (11); - Cause the excitation beam (11) to be scattered and / or transmitted through the flowing fluid (200) to form a first beam (12); - Reflect the first beam (12) into a reflected beam (13) directed toward the flowing fluid (200), and cause the reflected beam (13) to be scattered and / or transmitted through the flowing fluid (200) to form a second beam (14); - Generate spectral measurements based on the second beam (14) using a Raman spectrometer (45); - Measure the pressure of the flowing fluid (200); - Calculate the concentration of the at least one chemical component based on the spectral measurements and the pressure of the flowing fluid (200).

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