FR3153153A1 - System for measuring the concentration of at least one chemical component of a flowing fluid - Google Patents

Abstract

The invention relates to a system (100) for measuring a concentration of at least one chemical component of a flowing fluid (200) comprising: - a light source (10) configured to emit an excitation light beam (11), - a measuring cell (20) comprising a fluid conduit adapted to a flow of the fluid comprising portholes (23, 24) respectively arranged to receive the excitation light beam and transmit a first light beam (12) formed by diffusion and/or transmission of the excitation light beam through the fluid, - an optical device (30) positioned to reflect the first light beam and form a reflected light beam (13) in the direction of the fluid, a second light beam (14) being formed by diffusion and/or transmission of the reflected light beam through the fluid, - a Raman spectrometer (45) configured to receive the second light beam and generate a spectrometry measurement, - a pressure sensor (50) adapted to measure a pressure of the fluid, - a computing unit (60) programmed to determine the concentration of at least one chemical component based on the spectrometry measurement and the fluid pressure. Figure for abstract: Fig. 1

Description

System for measuring the concentration of at least one chemical component of a flowing fluid Technical field of the invention

The present invention relates generally to the measurement of concentration in fluids, in particular gases.

It relates more particularly to a system for measuring a concentration of at least one chemical component of a flowing fluid for an electrochemical generator system of the fuel cell or electrolyser type.

The invention finds a particularly advantageous application in the measurement of gas entering or leaving such an electrochemical generator system.

State of the art

An electrochemical generator system such as a fuel cell generates electrical energy from the oxidation of fuel. This fuel is, for example, hydrogen. This produces electricity from hydrogen.

Conversely, an electrochemical generator system such as an electrolyzer can generate a chemical component from electrical energy. For example, an electrochemical generator system comprising an electrolytic cell based on the electrolysis of water can generate hydrogen and oxygen using electrical energy. This results in the generation of hydrogen.

In order to be able to characterize the state of such an electrochemical generator system in operation, and thus estimate the performance in real time, it is necessary to measure the concentrations of the different chemical elements entering and/or leaving the electrochemical generator system.

Solutions consist of extracting part of the gas at the inlet or outlet of the electrochemical generator system and analyzing said gas with or without destroying the extracted sample. In practice, part of the flow is diverted to a measuring system in which the pressure is controlled. However, this extraction causes disturbances in the operation of the electrochemical generator system.

Furthermore, during the operation of the electrochemical generator system, the pressure of the flowing fluid is likely to vary, particularly when it passes from a resting state to an active state. For example, the use of the electrochemical generator system for generating current is accompanied by a higher consumption of dihydrogen and a high production of water, which leads to a reduction in the pressure at the outlet of the electrochemical generator system.

Presentation of the invention

In this context, the present invention provides a system for measuring a concentration of at least one chemical component of a flowing fluid for an electrochemical generator system, the measuring system comprising:
- a light source configured to emit an excitation light beam,
- a measuring cell comprising a fluid conduit adapted to a flow of the fluid in flux, the measuring cell comprising two sealed portholes arranged laterally on the fluid conduit and positioned opposite one another on a main optical axis transverse to the fluid conduit, the portholes being respectively arranged to receive the excitation light beam and transmit a first light beam formed by diffusion and/or transmission of the excitation light beam through the fluid in flux,
- an at least partially reflective optical device positioned to reflect the first light beam and form a reflected light beam in the direction of the flowing fluid, the portholes being respectively arranged to receive the reflected light beam and transmit a second light beam formed by diffusion and/or transmission of the reflected light beam through the flowing fluid,
- a Raman spectrometer configured to receive the second light beam and generate, based on the second light beam, a spectrometry measurement,
- a pressure sensor suitable for measuring the pressure of the flowing fluid,
- a computing unit programmed to determine the concentration of the at least one chemical component on the basis of the spectrometry measurement and the pressure of the flowing fluid.

Thus, the measuring cell according to the invention makes it possible to measure the concentrations of the different chemical elements without diversion of the flow.

Furthermore, thanks to the invention, intrinsic variations in the pressure of the flowing fluid are taken into account when measuring the concentration. In other words, the signal from the spectrometer is corrected for pressure variations. This makes it possible to obtain a concentration measurement that is independent of the pressure of the flowing fluid.

Other advantageous and non-limiting characteristics of the system according to the invention, taken individually or in all technically possible combinations, are the following:
- 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 connected pressure sensor;
- the pressure sensor is suitable for measuring a pressure lower than 6 bars;
- the pressure sensor is adapted to measure the pressure of the flowing fluid repeatedly at a frequency between 0.1 and 10 Hz;
- the at least one chemical component is selected from water, nitrogen, hydrogen and oxygen;
- the computing unit is programmed to calculate the concentration of the at least one chemical component on the basis of a division of the spectrometry measurement by the pressure of the flowing fluid;
- the at least one chemical component is also present in the ambient air, and the computing unit is programmed to apply a correction to the spectrometry measurement based on a reference spectrometry measurement generated by the spectrometer when a reference flow fluid that is devoid of said chemical component flows in the fluid conduit.

The invention also provides a method for measuring a concentration of at least one chemical component of a flowing fluid comprising the following steps:
- emission of an excitation light beam;
- diffusion and/or transmission of the excitation light beam through the flowing fluid so as to form a first light beam;
- reflection of the first light beam into a light beam reflected towards the flowing fluid and diffusion and/or transmission of the reflected light beam through the flowing fluid so as to form a second light beam;
- generation, by a Raman spectrometer, of a spectrometry measurement based on the second light beam;
- measurement of fluid pressure in flow;
- calculation of the concentration of at least one chemical component based on the spectrometry measurement and the pressure of the flowing fluid.

Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

Detailed description of the invention

The description which follows with reference to the attached drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

On the attached drawings:

FIG. 1 is a schematic representation of a measuring system according to the invention.

FIG. 2 is a block diagram of a sequence of steps for measuring the concentration of a chemical component of a flowing fluid.

FIG. 3 is a graphical representation of two signals from a spectrometer of the system of the FIG. 1 .

FIG. 4 is a graphical representation of a spectrum obtained by the spectrometer of the system of the FIG. 1 .

FIG. 5 is a graphical representation of the concentrations (in percentage) of two chemical components of a flowing fluid, measured using the system of FIG. 1 , over time.

On the FIG. 1 , a schematic view of a measuring system 100 is shown, making it possible in particular to measure concentrations 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. The term "flowing" here means, as will be clearly understood below, that the flowing fluid 200 is flowing at the time of measurement. The flowing fluid 200 is subsequently simply called fluid 200.

As shown in the FIG. 1 , the measuring system 100 here comprises a light source 10, a measuring cell 20, an optical device 30, a spectrometer 45, a pressure sensor 50 and a calculation unit 60.

The measuring system 100 is particularly suitable for measuring the fluid 200 coming from or supplying 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 used for the production of hydrogen. The electrochemical generator system 301 then consumes electricity in order to produce hydrogen.

In another application, the electrochemical generator system 301 is used to generate electricity. In this case, the electrochemical generator system 301 consumes a fuel, for example hydrogen, in order to produce electricity.

The spectrometer 45 is particularly suitable for measuring the concentration of at least one chemical component of the fluid 200 among water, for example in the form of water vapor, nitrogen, hydrogen and oxygen.

Thus, the spectrometer 45 is preferably a Raman spectrometer.

Here, as shown in the FIG. 1 , the light source 10 and the spectrometer 45 are here part of a spectrometry device 40. In the example of the FIG. 1 , the spectrometry device 40 is placed opposite the measuring cell 20. Conventionally, the light source 10 and the spectrometer 45 could be placed at a distance from the measuring cell 20 and the light beams could be routed using fiber optic cables.

The light source 10 is preferably a laser having a high intensity. Here, the light source 10 is for example a laser with a power of 1.5 W which emits a monochromatic light beam at a wavelength of 532 nm. The light source 10 is of high power in order to obtain a Raman signal having an intensity sufficiently strong to allow an integration time compatible with real-time monitoring, for example at a rate of between 0.1 Hz and 10 Hz. Alternatively, the excitation light beam is generated from any light source suitable for Raman spectrometry. The light source 10 is for example controlled by the spectrometer 45.

The measuring cell 20 comprises an inlet opening 21, an outlet opening 22, a first porthole 23, a second porthole 24 and a casing 25. The ports 23, 24 are positioned at lateral openings provided in the casing 25. The casing 25 and the ports 23, 24 here delimit a fluid conduit inside which the fluid 200 flows. The fluid conduit therefore extends from the inlet opening 21 to the outlet opening 22 of the measuring cell 20.

As represented in FIG. 1 , the inlet opening 21 is connected to a first conveying conduit 302 for the fluid 200, itself connected to the electrochemical generator system 301. This first conveying conduit 302 thus fluidically connects the electrochemical generator system 301 to the measuring cell 20. The outlet opening 22 is connected to a second conveying conduit 303 for the fluid 2, itself connected to a reservoir 304 designed to collect the fluid 200. This second conveying conduit 304 thus fluidically connects the measuring cell 20 to the reservoir 304.

So, as it is represented on the FIG. 1 , the measuring cell 20 makes it possible to carry out measurements on the outgoing fluid 200, i.e. produced by the electrochemical generator system 301. As shown in the FIG. 1 , the measuring cell 20 is for example connected to an output of an electrolyzer for the generation of hydrogen.

Of course, conversely, the outlet opening can be connected to a fluid flow conduit at the inlet of the electrochemical generator system. In this case, the measuring cell can be used to carry out measurements on the fluid entering the electrochemical generator system. The measuring cell is, for example, connected to an inlet of an electrochemical generator system of the hydrogen fuel cell type for generating electricity from hydrogen.

In order not to cause any change in pressure or flow rate of the fluid 200, the section of the inlet opening 21, the section of the outlet opening 22 and the section of the casing 25 are each greater than or equal to the section of the conveying conduits 302, 303 of the fluid 200.

The portholes 23, 24 are watertight, which means that the fluid 200 cannot escape from the fluid conduit at the side openings.

Here, the measuring cell 20 comprises seals (not shown) interposed between the casing 25 and the portholes 23, 24. The measuring cell 20 comprises, for example, one seal per porthole 23, 24.

For example, seals are made from a fluoroelastomer material (commonly called FKM or viton).

Here, the term “porthole” is understood to mean a glazed part of any shape allowing optical access to the interior of the casing 25, that is to say to the interior of the fluid conduit.

Thus, each porthole 23, 24 here comprises a glass slide. These glass slides are preferably made from a borosilicate or aluminosilicate glass or an alkali-aluminosilicate glass, for example from BK7 or with Gorilla Glass. Preferably, the glass slides do not have a surface coating on their face in contact with the fluid 200 (i.e. their face oriented towards the inside of the casing 25). The composition and arrangement of the glass slides make it possible to avoid any degassing or contamination of the fluid 200 which would be likely to pollute the measurement.

The two portholes 23, 24 are arranged laterally on the casing 25 downstream of the inlet opening 21 and upstream of the outlet opening 22 with reference to the flow of the fluid 200. The two portholes 23, 24 are positioned opposite one another. For example, when the casing 25 is of circular section, the two portholes 23, 24 are arranged diametrically opposite one another. In another example, when the casing 25 is of square or rectangular section, the two portholes 23, 24 are arranged on two opposite faces of the casing 25. In all cases, the two portholes 23, 24 are arranged so that the fluid 200 flows between the portholes 23, 24.

As it appears on the FIG. 1 , the measuring cell 20 is arranged so that the two portholes 23, 24 are aligned on a main optical axis OA transverse to the direction of flow of the fluid 200. This means that the portholes 23, 24, and more particularly their glass plate, intersect the main optical axis OA. In the example shown in FIG. 1 , the principal optical axis OA is more specifically perpendicular to the direction of flow of the fluid 200.

The two portholes 23, 24, and more particularly their glass blade, are configured to transmit the excitation light beam 11. Preferably, as shown in the FIG. 1 , the excitation light beam 11 propagates along a main illumination axis aligned with the main optical axis OA, i.e. parallel to the main optical axis OA.

The system 1 also comprises an optical element 70 arranged on the path of the excitation light beam 11, between the light source 10 and the first porthole 23. The optical element 70 is configured to focus the excitation light beam 11 in the fluid 200 between the two ports 23, 24 of the measuring cell 20. The optical element 70 is for example a lens or an objective.

The optical device 30 is at least partially reflective. Preferably, the optical device 30 is a concave mirror. The device 30 comprises, for example, a spherical mirror arranged so that its center of curvature is on the main optical axis OA, equidistant between the two portholes 23, 24.

As shown in the FIG. 1 , the optical device 30 is arranged opposite the second porthole 24. The optical device 30 thus makes it possible to reflect the light coming from the latter towards the second porthole 24. The optical device 30 is therefore placed opposite the light source 10 relative to the measuring cell 20.

The measuring cell 20 is thus of the double pass type because, associated with the optical device 30, it allows double excitation of the fluid 200. Indeed, the excitation beam 11 passes through the measuring cell 20 and is then refocused in the fluid 200, which makes it possible to double the excitation. This optical configuration also has the advantage of doubling the solid collection angle by collecting the light emitted towards the spectrometer 45 but also that emitted towards the optical device 30 which is then reflected and returned to the spectrometer 45. The term “double pass” is thus linked to the round trip path of the light beam in the measuring cell 20. However, the fluid 200 only passes through the measuring cell 20 once, in the direction of the flow, without interruption of the flow.

The pressure sensor 50 is adapted to measure a pressure of the fluid 200. The pressure sensor 50 is more particularly adapted to measure the pressure of the fluid 200 in the measuring cell 20, that is to say in the fluid conduit. The sections of the conveying conduits 302, 303 and of the casing 25 being chosen to avoid pressure changes, the pressure of the fluid 200 can in practice be measured in the conveying conduits 302, 303 or in the fluid conduit. The pressure sensor 50 can therefore be placed at these locations.

However, the pressure sensor 50 is preferably placed in the measuring cell 20, i.e. inside the fluid conduit. It is for example arranged against the casing 25, and more specifically against the face of the casing 25 which is in contact with the fluid 200, as shown in FIG. 1 .

Even more preferably, the pressure sensor 50 is located less than 10 cm from one of the portholes 23, 24.

The pressure sensor 50 is preferably a connected pressure sensor, which simplifies its connection with the computing unit 60. Alternatively, the pressure sensor may be a pressure gauge.

The pressure sensor 50 is suitable for measuring pressures between 0 and 6 bars. Preferably, the pressure sensor 50 is adapted to measure the pressure of the fluid 200 at a frequency between 0.1 Hz and 10 Hz.

The computing unit 60 comprises at least one memory and at least one processor. The computing unit 60 also comprises interfaces allowing the computing unit 60 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 acquisitions from the spectrometer 45 and the pressure sensor 50, which means that the computing unit 60 controls the data acquisitions.

The memory of the computing unit 60 is a computer-readable recording medium comprising instructions which, when executed by the processor, make it possible to determine the concentration of at least one chemical component of the fluid 200 on the basis of data provided by the spectrometer 45 and the pressure sensor 50.

The measuring system 100 makes it possible to implement a method for measuring the concentration of at least one chemical component of the fluid 200. This method is described with reference to Figures 3 to 5. In these figures, the fluid 200 comprises, for example, two components, namely nitrogen and hydrogen. For illustrative purposes, the concentrations are predetermined: the nitrogen concentration is 20% and the hydrogen concentration is 80%. Here, we will verify that the method makes it possible to find these predetermined concentrations by measurement. Similarly, in these figures, the pressure variations of the fluid 200 are monitored.

Preferably, the steps of the method are repeated to allow monitoring of concentrations in real time, i.e. continuously. However, it is possible to implement these steps only once to obtain a single measurement at a given time.

As shown in the FIG. 2 , this method begins with a first step E1 of emission of the excitation light beam 11 by the light source 10.

The method continues with a second step E2 comprising the diffusion and/or transmission of the excitation light beam 11 through the fluid 200 so as to form a first light beam 12.

As visible on the FIG. 1 , this second step E2 also comprises the transmission of the excitation light beam 11 through the first porthole 23 and the transmission of the first light beam 12 through the second porthole 24. The first light beam 12 passes through the second porthole 24 towards the optical device 30.

The method then comprises a third step E3 in which the optical device 30 reflects the first light beam 12 into a reflected light beam 13 in the direction of the second porthole 24, and therefore in the direction of the fluid 200. The optical device 30 is positioned to receive the first light beam 12. The reflective optical device 30 is positioned outside the measuring cell 20. This arrangement avoids any interaction between the fluid 200 and a reflective coating, for example metallic, of the optical device 30, which makes it possible to avoid polluting the fluid 200. The optical device 30 is configured to focus the reflected light beam 13 in the measuring cell 20 between the two portholes 23, 24, for example in the middle of the two portholes 23, 24.

The method then comprises a fourth step E4 comprising the diffusion and/or transmission of the reflected light beam 13 through the fluid 200 so as to form a second light beam 14.

As visible on the FIG. 1 , this fourth step E4 also comprises the transmission of the reflected light beam 13 by the second porthole 24 and the transmission of the second light beam 14 by the first porthole 23. The second light beam 14 passes through the first porthole 23 in the direction of the optical element 70. The optical element 70 makes it possible to focus the second light beam 14 in the direction of the spectrometer 45.

The method then comprises a fifth step E5 of generation, by the spectrometer 45, of at least one spectrometry measurement on the basis of the second light beam 14. The spectrometer 45 here generates one spectrometry measurement per chemical component, i.e. here one for nitrogen and one for hydrogen.

When the fifth step E5 is repeated over time (for example every second), all the spectrometry measurements associated with each chemical component form a spectrometry signal associated with this chemical component. Each signal therefore comprises several measurements. The measurements are, for example, generated at a frequency between 0.1 Hz and 1 Hz.

In the example of the FIG. 3 , the spectrometer 45 here generates a first spectrometry signal 41 for nitrogen and a second spectrometry signal 42 for hydrogen. In this example, the spectrometry measurements are generated every second over a period of approximately one hour.

In order to carry out these measurements, the spectrometer 45 is configured to receive the second light beam 14, which here comprises Raman signals emitted by the fluid 200. The spectrometer 45 is more particularly adapted to detect, in the second light beam 14, a Raman signal emitted by the fluid 200. The Raman signal is emitted in particular thanks to the excitation of the fluid 200 by the excitation light beam 11 and by the reflected light beam 13. Conventionally, the spectrometer 45 comprises a diffraction grating and a light sensor. It also comprises a processing system for reading the light sensor and deducing the spectrometry measurements therefrom.

Spectrometry measurements can be deduced from a spectrum obtained by summing a part of the pixels of the same column of the light sensor. FIG. 4 represents an example of such a Raman spectrum. On the Raman spectrum of the FIG. 4 , an intensity I of the signal provided by the light sensor is represented as a function of the Raman shift Δω (in cm ^-1 ). This intensity I presents in particular a first peak at approximately 2301 cm ^-1 corresponding to dinitrogen (N ₂ ) and a second peak at approximately 4100 cm ^-1 corresponding to dihydrogen (H ₂ ). On the FIG. 4 , the intensities are presented in arbitrary units corresponding for example to a photon count by the light sensor. These spectra are for example generated at a frequency between 0.1 Hz and 1 Hz.

Conventionally, for each chemical component, the spectrometry measurement can correspond to the height of the associated peak (for example the peak maximum), or to the area of this peak, i.e. the surface of this peak which is for example calculated for a predetermined shift interval.

Each spectrometry measurement depends on the concentration of the chemical element in the fluid 200, the pressure of the fluid 200 and the power of the excitation beam 11 (the latter being known). Here, each spectrometry measurement depends in a globally linear manner on the pressure of the fluid 200.

Thus, as shown in the FIG. 3 , the first spectrometry signal 41 and the second spectrometry signal 42 vary when the fluid pressure 200 varies. On the FIG. 3 , the pressure of the fluid 200 varies in stages and in a controlled manner. The pressure of the fluid 200 is here incremented or decremented approximately every 240 seconds by ±0.1 bar ±0.2 bar or ±0.3 bar. As a result, the spectrometry signals 41, 42 also vary in stages, which is particularly visible for dihydrogen which is present in greater concentration. On the FIG. 3 , the peaks visible between the levels correspond here to transient regimes during pressure changes, the pressure then being momentarily excessive before stabilizing at the requested pressure.

In order to take into account pressure variations, the method comprises a sixth step E6 of measuring the pressure of the fluid 200 by means of the pressure sensor 50. As shown in FIG. 2 , the sixth step E6 is implemented in parallel with steps E1 to E5.

The pressure measurement is preferably performed synchronously with the spectrometry measurement of each chemical component. Also, when the spectrometry measurements are generated every second, the pressure is preferably also measured every second. Typically, the pressure is, for example, measured at a frequency between 0.1 Hz and 10 Hz.

Each pressure measurement made by the pressure sensor 50 provides the calculation unit 60 with a pressure value.

The calculation unit 60 is then programmed to calculate, during a seventh step E7 of the method, a concentration of each chemical component. More specifically, it calculates a concentration for each spectrometry measurement.

Here we describe in detail the calculation of the concentration only for one spectrometry measurement, and therefore only for one chemical component, called the chemical component.

The computing unit 60 first associates the spectrometry measurement with a pressure value, more specifically the pressure value corresponding to the time when the spectrometry measurement is generated. The spectrometry measurement and the pressure measurement associated with it are therefore concomitant, and preferably simultaneous. Here, this means, for example, that the pressure measurement and the spectrometry measurement are separated by less than 10 seconds and preferably by less than 5 seconds and even more preferably by less than 1 second.

The seventh step E7 then includes the conversion of the spectrometry measurement into the initial concentration of the chemical component by means of a calibration function.

The calibration function is here pre-recorded in the memory of the calculation unit 60. The calibration function is representative of an affine relationship between the spectrometry measurement and the concentration of the chemical component. It is for example determined by measuring a standard fluid comprising a known concentration of the chemical component. The calibration function is established for a predetermined and controlled reference pressure of the standard fluid. The calibration function is for example established for a reference pressure of between 1 and 2 bars. For example, it is established here for a reference pressure of 1.5 bars.

The calibration function is specific to the chemical component. In practice, the computing unit 60 therefore has in memory a calibration function per chemical component.

The initial concentration of the chemical component is currently dependent on the fluid pressure 200.

The seventh step E7 then includes the calculation of an intermediate concentration of the chemical component by multiplying the initial concentration of the chemical component by the reference pressure, i.e. the pressure at which the calibration function was established. The initial concentration is therefore, for example, multiplied by a factor of 1.5 corresponding to the reference pressure mentioned in the example above. When the calibration has been carried out at a reference pressure of 1 bar, this calculation is optional since it amounts to multiplying the initial concentration by 1.

The seventh step E7 then comprises the calculation of the concentration of the chemical component by dividing the intermediate concentration by the pressure value, provided by the pressure sensor 50 in the sixth step E6, which is associated with the spectrometry measurement.

The concentration is then independent of the pressure of the fluid 200.

When spectrometry measurements are repeated over time, the entire concentration range can be plotted for each chemical component. FIG. 5 illustrates the concentrations (in percentage) of fluid 200 on the same time scale as that of the FIG. 3 . In this figure, we observe that fluid 200 does indeed have stable concentrations despite the pressure changes in steps. The calculated concentration of nitrogen is approximately 20% and that of hydrogen approximately 80% (which gives a total concentration of chemical component of 100%). The data represented on the FIG. 5 thus correspond to those of the FIG. 3 once corrected for pressure. The peaks visible on the FIG. 5 correspond here again to the transient regimes during pressure changes.

When spectrometry measurements are repeated over time, it can be noted that the same pressure value can be associated with several successive spectrometry measurements, in particular when the frequency of generation of the spectrometry measurements is higher than that of pressure measurement. However, as mentioned previously, the frequency of generation of the spectrometry measurements is preferably equal to that of pressure measurement.

When the chemical component of interest, i.e. the one whose concentration is to be measured, is also present in the air, an additional correction is applied. Typically, this correction is applied for nitrogen. Indeed, the different light beams will interact with this component present in the air, which is not sensitive to pressure variations in the fluid conduit.

It is therefore planned to acquire a reference spectrometry measurement generated by the spectrometer 45 when a flowing fluid devoid of this chemical component, here nitrogen, flows in the fluid conduit.

Prior to converting the spectrometry measurement into an initial concentration, the spectrometry measurement is corrected for the reference signal. In practice, the calculation unit 60 calculates a difference between the nitrogen spectrometry measurement and the reference measurement, which allows the contribution of the ambient air to be subtracted. This difference is then converted into an initial concentration.

The present invention is in no way limited to the embodiments described and shown, but those skilled in the art will be able to provide any variation in accordance with the invention.

For example, pressure values can of course be expressed in units other than bars. It is only necessary that the pressure values are expressed in the same units for all calculations in step seven E7.

Claims (10)

A system (100) for measuring a concentration of at least one chemical component of a flowing fluid (200) for an electrochemical generator system (301), the measuring system (100) comprising:
- a light source (10) configured to emit an excitation light beam (11),
- a measuring cell (20) comprising a fluid conduit adapted to a flow of the fluid in flux (200), the measuring cell (20) comprising two sealed portholes (23, 24) arranged laterally on the fluid conduit and positioned opposite one another on a main optical axis (OA) transverse to the fluid conduit, the portholes (23, 24) being respectively arranged to receive the excitation light beam (11) and transmit a first light beam (12) formed by diffusion and/or transmission of the excitation light beam (11) through the fluid in flux (200),
- an optical device (30) at least partially reflecting positioned to reflect the first light beam (12) and form a reflected light beam (13) towards the flowing fluid (200), the portholes (23, 24) being respectively arranged to receive the reflected light beam (13) and transmit a second light beam (14) formed by diffusion and/or transmission of the reflected light beam (13) through the flowing fluid (200),
- a Raman spectrometer (45) configured to receive the second light beam (14) and generate, based on the second light beam (14), a spectrometry measurement,
- a pressure sensor (50) adapted to measure a pressure of the flowing fluid (200),
- a computing unit (60) programmed to determine the concentration of the at least one chemical component on the basis of the spectrometry measurement and the pressure of the flowing fluid (200). The system (100) of claim 1, wherein the pressure sensor (50) is arranged inside the fluid conduit. System (100) according to claim 1 or 2, wherein the pressure sensor (50) is positioned less than 10 cm from one of the portholes (23, 24). System (100) according to one of claims 1 to 3, wherein the pressure sensor (50) is a pressure gauge or a connected pressure sensor. System (100) according to one of claims 1 to 4, in which the pressure sensor (50) is adapted to measure a pressure less than 6 bars. System (100) according to one of claims 1 to 5, wherein the pressure sensor (50) is adapted to measure the pressure of the flowing fluid (200) repeatedly at a frequency of between 0.1 and 10 Hz. System (100) according to one of claims 1 to 6, wherein the at least one chemical component is selected from water, nitrogen, hydrogen and oxygen. System (100) according to one of claims 1 to 7, wherein the calculation unit (60) is programmed to calculate the concentration of the at least one chemical component on the basis of a division of the spectrometry measurement by the pressure of the flowing fluid (200). System (100) according to one of claims 1 to 8, wherein the at least one chemical component is also present in the ambient air, and wherein the computing unit (60) is programmed to apply a correction to the spectrometry measurement on the basis of a reference spectrometry measurement generated by the spectrometer (45) when a reference flowing fluid (200) which is devoid of said chemical component flows in the fluid conduit. A method for measuring a concentration of at least one chemical component of a flowing fluid (200) comprising the following steps:
- emission of an excitation light beam (11);
- diffusion and/or transmission of the excitation light beam (11) through the flowing fluid (200) so as to form a first light beam (12);
- reflection of the first light beam (12) into a reflected light beam (13) in the direction of the flowing fluid (200) and diffusion and/or transmission of the reflected light beam (13) through the flowing fluid (200) so as to form a second light beam (14);
- generation, by a Raman spectrometer (45) of a spectrometry measurement on the basis of the second light beam (14);
- measurement of a pressure of the fluid in flow (200);
- calculating the concentration of the at least one chemical component based on the spectrometry measurement and the pressure of the flowing fluid (200).