Electrolysis system comprising a rapid gas detection device

Abstract

The invention relates to a water electrolysis system (2) comprising an electrolyser with electrolytic membranes (21) and a separator (22) intended to carry out a liquid / gas separation of a fluid supplied by the electrolyser (21), the separator (22) comprising an inlet portion (221) connected to the electrolyser (21), a liquid / gas separation space (223) and an outlet portion (22) through which a gas mixture exits, characterised in that the water electrolysis system (2) comprises a device (25) for detecting a gas contained in the gas mixture, said detection device (25) being connected to the inlet portion (221) of the separator (22).

Description

[0001]DESCRIPTION Title of the invention: Electrolysis system comprising a rapid gas detection device. The present invention relates to the field of water electrolysis and, more particularly, to the analysis of gases present in the streams from electrolyzers. Water electrolysis is a technique that consists of dissociating water molecules into gaseous oxygen and hydrogen by passing an electric current through water. The oxygen and hydrogen formed by water electrolysis can then be used in numerous applications. The oxygen produced by water electrolysis has multiple uses in industry and the environment. For example, it is useful in water purification processes by helping to remove contaminants and can also be used to reoxygenate aquatic environments to support ecological regeneration.Furthermore, dioxygen is notably used in oxy-combustion processes for glassmaking and is widely used in medical systems for oxygen cylinders and certain other applications requiring high purity. Water electrolysis thus allows the production of two streams: one composed of a first gas and water, and the other composed of a second gas and water. To obtain these pure gases, the first and second gases must be separated from the water contained in their respective streams. This separation is typically carried out in large tanks called separators, where the first gas and water, and / or the second gas and water, are separated by gravity. The water collects at the bottom of the separator, while the first or second gas rises to the top. It should be noted that the first gas obtained after water electrolysis may contain traces of the second gas, and vice versa.A major challenge in producing these gases by water electrolysis is the risk of explosion due to the reaction between the first and second gases. For example, when the first gas is oxygen and the second gas is hydrogen, there is a particular risk of explosion when the concentration of hydrogen in the oxygen exceeds 4%. To counter this risk of explosion, separators are equipped with analytical systems that detect the presence and concentration of the first gas mixed with the second gas, or of the second gas mixed with the first gas. These analytical systems are designed to stop the electrolysis process if a critical level of either the first or second gas is reached.However, these analysis systems have limitations, especially in large separators, where the time required to transport the gas to the analysis system can be significant, thus delaying detection and all subsequent steps to ensure the safety of the installation. The limit of the first gas within the second gas, or the limit of the second gas within the first gas, may then be exceeded before the analysis system can detect it. This problem is exacerbated in industrial settings where electrolyzers are designed to operate over a wide range of capacities. The analysis systems may then fail to provide sufficiently rapid responses, particularly when the electrolyzers are operating well below their maximum capacity, for example, at 10% of their rated power.Indeed, this type of practice results in a reduced flow rate, prolonging the gas transit time and, consequently, the time required for analytical systems to react. If detection is too slow, the system may not intervene before the concentration of the first or second gas reaches the critical threshold, thus posing a significant risk of contamination of the first or second gas by the second or first gas, thereby increasing the risk of explosion. The objective of the invention described in this document is therefore to overcome the disadvantages of the prior art by presenting a water electrolysis system comprising a gas detection device in a gas mixture, designed to allow a reduced transit time for this gas for analysis. This reduced transit time thus helps to avoid dangerous situations related to high levels of said gas.The present invention relates primarily to a water electrolysis system comprising an electrolyzer with electrolytic membranes and a separator for performing liquid / gas separation of a fluid supplied by the electrolyzer. The separator comprises an inlet portion connected to the electrolyzer, a liquid / gas separation volume, and an outlet portion through which a gaseous mixture exits. The system is characterized in that the water electrolysis system includes a device for detecting a gas contained in the gaseous mixture, said detection device being connected to the inlet portion of the separator. The electrolyzer is therefore an electrolyzer with electrolytic membranes. It thus comprises at least one assembly consisting of an anode and a cathode separated by an electrolytic membrane. Water flows through the electrolyzer and, through the application of an electric current, forms dioxygen and dihydrogen.The electrolytic membrane electrolyzer is also called a proton exchange membrane electrolyzer and is commonly referred to by the acronym PEM electrolyzer. At the cathode end, the electrolyzer produces a mixture of hydrogen and water. At the anode end, it produces a fluid containing water and a gaseous mixture, this gaseous mixture being primarily composed of oxygen and, to a lesser extent, hydrogen. The separator is designed to separate the gaseous mixture and water from the fluid produced by the electrolyzer's anode. The inlet portion of the separator allows the fluid that has been delivered from the electrolyzer to enter the separator. The separator, as mentioned previously, comprises a separation volume that is typically tank-shaped. Within this separation volume, the water falls by gravity into the lower part of the separation volume, while the gaseous mixture accumulates in the upper part.The outlet portion allows the gas mixture to be discharged from the separator. The detection device is connected to the inlet portion of the separator. This means it is directly connected to the inlet portion; there are no intermediate components between the detection device and the inlet portion, apart from a fluid transport line. Thus, thanks to this direct connection and the fact that the detection device is connected to the inlet portion of the separator, the gas present in the gas mixture is detected more quickly. Indeed, these characteristics allow the gas to be detected before it passes through the separator. Consequently, the transit time is very short, leading to very rapid detection of the gas in the gas mixture.This process therefore allows for a rapid response to excessively high gas concentrations, even if the system is operating at a low flow rate. It should be noted that the transit time represents the time required for the gas to be detected by the detection device after being produced by the electrolyzer. According to an optional feature of the invention, the detection device comprises at least one gas detection line and at least one flow acceleration means that increases the flow rate of the gas mixture circulating in the gas detection line. The gas detection line is an element of the detection device comprising a means designed to detect the gas in the gas mixture. The flow acceleration means increases the flow rate of the gas mixture in the gas detection line. Furthermore, this flow acceleration means also increases the flow rate in the rest of the detection device.This flow rate acceleration further reduces the transit time, thus enabling a rapid response to the gas concentration measured by the detection device. The flow rate acceleration method is generally an acceleration line that draws a portion of the gas mixture passing through the detection device. This acceleration increases the overall velocity of the gas mixture flowing through the detection device. According to an optional feature of the invention, the detection device includes a liquid-gas separator, the separator being connected to the inlet portion of the separator. The separator is designed to separate the gas mixture from the water in the fluid drawn from the inlet portion of the separator.It is important to understand that the separator is directly connected to the inlet; that is, it is the element of the detection device that is in direct contact with the inlet portion of the separator. This separator is positioned in this way so that only the gas mixture flows through the rest of the detection device. This optimizes detection and allows for the determination of a precise gas concentration while avoiding the presence of water from the fluid. According to an optional feature of the invention, the separator includes at least one heat exchanger containing spheres that increase the contact surface area with the fluid. The heat exchanger cools the fluid drawn from the inlet portion by exchanging heat with a third fluid. To maximize this heat transfer, the heat exchanger includes spheres. These spheres increase the contact surface area between the heat exchanger and the fluid.Consequently, water accumulates on the outer periphery of the spheres and falls by gravity into the inlet portion, while the gas mixture is drawn into the rest of the detection device. According to an optional feature of the invention, the detection line includes a detector for said gas. The detector can, for example, be used to detect dihydrogen in a mixture containing predominantly dioxygen and a minority of dihydrogen, thus enabling the detection of low levels of dihydrogen. More specifically, it can be designed to detect if the dihydrogen level exceeds 2% of the gas mixture in order to shut down the electrolysis system and prevent a potentially explosive situation when the level reaches 4%. According to an optional feature of the invention, the detection line includes at least one pressure regulator, a flow control valve, and the detector for said gas.The pressure regulator lowers the pressure of the gas mixture so that, when the gas mixture reaches the detector, the detector can accurately measure the gas without being damaged. Similarly, the flow control valve controls the flow rate of the gas mixture so that the detector can perform an optimal measurement of the gas contained in the mixture and avoid damage. It should be noted that, optionally, the detection line may consist solely of the gas detector. According to an optional feature of the invention, the flow control valve is located between the pressure regulator and the detector. It should be understood that, when the gas mixture flows through the detection device, it first passes through the pressure regulator, then through the flow control valve, and finally through the detector.This sequence first reduces the pressure and then regulates the flow rate, so that the gas mixture reaches the detector with the appropriate pressure and flow rate. According to an optional feature of the invention, the flow acceleration means includes an inlet connected to the detection line and positioned upstream of the gas detector in the direction of gas flow. According to another optional feature of the invention, the flow acceleration means includes an outlet positioned downstream of the gas detector in the direction of gas flow. According to yet another optional feature of the invention, the inlet is positioned between the separator and the pressure regulator.When the inlet of the flow accelerator is connected to the detection line, the gas mixture flowing through the detection device is split into two parts: one part flows through the detection line, and the other part passes through the inlet of the flow accelerator. The point where the gas mixture is thus split is the inlet of the flow accelerator, and it is located between the separator and the pressure regulator. Optionally, the outlet can be connected to the detection line. This outlet is connected so that it is positioned at a point on the detection line where the gas mixture has already passed through the detector. In this way, the portion of the gas mixture drawn by the flow accelerator rejoins the portion of the gas mixture flowing through the detection line.This configuration creates a suction effect in the detection line, further reducing the transit time within the detection device. After circulating through the flow acceleration means, the gas mixture can either return to the detection line if the flow acceleration means includes an outlet connected to this detection line, or be vented. The gas mixture circulating in the detection line can also be vented. Thus, when the gas mixture that has circulated in the flow acceleration means rejoins the mixture that has circulated in the detection line, the resulting mixture can either join the gas mixture from the separator or be vented through a single vent. According to an optional feature of the invention, the flow acceleration means includes a flow control valve.This flow control valve allows control of the gas mixture flow rate in the flow acceleration means. Thus, by adjusting the gas mixture flow rate in the acceleration means, the gas mixture flow rate in the detection device can be increased or decreased, thereby controlling the gas transit time. According to an optional feature of the invention, the detection line is designed to detect the presence of dihydrogen in a gas mixture containing at least dioxygen. In this case, the fluid is composed of water and a gas mixture consisting primarily of dioxygen and, to a lesser extent, dihydrogen. For these gases, the explosive limit is set at 4% dihydrogen in dioxygen. The detection line is designed to detect a dihydrogen concentration starting at 2% and subsequently trigger the shutdown of the electrolysis system.According to an optional feature of the invention, the flow acceleration means is configured so that the flow rate of the detection line is between 1 and 2 NL / min. The flow rate of the detection line is influenced, in particular, by the setting of the regulating valve of the acceleration means, by the setting of the regulating valve of the detection line, and by the pressure upstream and downstream of the flow acceleration means. By way of example, the acceleration means is set to a flow rate approximately 10 times higher than the desired flow rate in the detection line; for example, a flow rate of 11 NL / min for a flow rate of 1 to 2 NL / min in the detection line. In another aspect, the invention relates to a method for detecting a gas within a gas mixture circulating in a water electrolysis system as described herein, during which the gas transit time is less than 15 seconds.Thanks to this particularly short transit time, the process allows for a rapid response to urgent situations where the gas concentration would increase rapidly. This prevents the gas concentration from becoming significant before the detection device has detected an anomaly. In the case of dihydrogen in dioxygen, the explosive limit is set at 4%, and the electrolysis system shuts down if the concentration exceeds 2%. This rapid transit time ensures that the measured concentration corresponds to the actual concentration within the separator. Other features, details, and advantages of the invention will become clearer upon reading the following description, on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings, on the other hand, in which: [Fig. 1] is a schematic diagram of an electrolysis system according to the prior art. [Fig.Figure 2] is a schematic diagram of an electrolysis system according to a first embodiment of the invention. Figure 3 is a schematic diagram of a separation element of a detection device for the electrolysis system according to the embodiment of Figure 2. Figure 4 is a schematic diagram of an electrolysis system according to a second embodiment of the invention. The features and variations of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived comprising only a selection of the features described below, isolated from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.In the figures, elements common to several figures retain the same reference numeral. Figure 1 is a schematic diagram of an electrolysis system 1 according to the prior art. In the prior art, electrolysis systems 1 may include an electrolyzer 11, a gas / liquid separator 12, and an analytical assembly 15. The electrolyzer 11 enables the formation of gas from water. In particular, it produces a fluid composed of water and a gas mixture, the fluid being then sent to the separator 12. This fluid is conveyed to the separator 12 via an inlet pipe 13. The gas mixture is primarily composed of a first gas, but a second gas may also be present. The first gas may, for example, be oxygen and the second gas may be hydrogen. Once introduced into the separator 12, the water is separated from the gas mixture by gravity.This process causes the water to flow down to a lower part of the separator 12, while the gas mixture accumulates in an upper part of the separator 12, also known as the separator 12 ceiling. The gas mixture in the upper part of the separator 12 is then discharged from the separator 12 through an outlet pipe 14. As mentioned earlier, when the first gas is oxygen and the second gas is hydrogen, it is necessary to detect the hydrogen present in the oxygen, since a concentration of 4% hydrogen in the gas mixture poses a risk of a major explosion due to a reaction between oxygen and hydrogen. For this purpose, the electrolysis system 1, according to the prior art, includes an analysis unit 15, which detects the concentration of hydrogen in the oxygen. The analysis unit 15 is connected to the outlet pipe 14 and collects the gas mixture from the separator for analysis.If the hydrogen concentration exceeds 2%, the analysis unit 15 sends stop signals to the electrolysis system 1 to prevent an explosive situation, i.e., a hydrogen concentration exceeding 4%. The problem with prior art technology lies in the significant transit time. Indeed, the hydrogen concentration is measured only after it has passed through the separator 12. Consequently, the measured concentration does not reflect the actual hydrogen concentration in the separator 12. For example, a detected concentration of 2% could actually correspond to a concentration exceeding 4% in the separator, which is above the explosive threshold. Due to the industrialization of water electrolysis processes, the size of separators tends to increase and their range of applications becomes broader, exacerbating these problems.Indeed, in large separators, and especially when using a low flow rate, the transit time is increased; thus, the analysis assembly 15 is unsatisfactory and cannot guarantee the absence of explosion risk. Figure 2 is a schematic diagram of an electrolysis system 2 according to a first embodiment of the invention. The electrolysis system 2 comprises at least one electrolyzer 21, a separator 22, an inlet pipe 23, an outlet pipe 24, and a detection device 25. The electrolyzer 21 is capable of performing water electrolysis, that is, extracting dioxygen and dihydrogen from water by applying an electric current. It is typically an electrolyzer with electrolytic membranes.Electrolytic membrane electrolyzers, such as electrolyzer 21, are part of the so-called polymer electrolyte membrane (PEM) technology. Such an electrolytic membrane is positioned between a cathode and an anode. The electrolytic membrane is permeable to protons but electrically insulating, meaning it is impermeable to electrons. Electrolyzer 21, through which a flow of water passes, applies an electric current so that oxygen and hydrogen ions are produced from the water at the anode. The hydrogen ions then migrate, carried by the electric current, to the cathode via the electrolytic membrane, where they are produced as hydrogen. Thus, with this technology, one side of the membrane is used for oxygen production and the other side for hydrogen production.The hydrogen is then recovered for processing, as is the oxygen. Electrolysis system 2, for example, is dedicated to processing the oxygen produced by this technology. Electrolyzer 21 delivers a fluid comprising a gas mixture and water. This fluid is exiting the anode and must be processed to extract only the gas mixture. This gas mixture, primarily composed of oxygen, may contain small quantities of other gases, such as hydrogen. Indeed, during electrolysis, hydrogen ions can remain at the anode and form hydrogen. This fluid is conveyed from electrolyzer 21 to separator 22 via the inlet pipe 23. Separator 22 is a large tank. This separator 22 includes an inlet portion 221, an outlet portion 222, and a liquid / gas separation volume 223 to separate the gas mixture from the water.The inlet portion 221 is a part of the separator 22 through which the fluid supplied by the electrolyzer 21 enters the separator 22. This inlet portion 221 is therefore connected to the electrolyzer 21 via the inlet pipe 23. In this figure, the inlet portion 221 is represented as a protrusion for ease of understanding. This is not mandatory, and the inlet portion 221 can, for example, be an integral part of the separation volume 223, as long as it constitutes the area through which the fluid enters the separator 22. The liquid / gas separation volume 223 is designed to separate the gaseous mixture of water from the fluid entering the separator 22 through the inlet portion 221. For example, for an electrolyzer with a capacity of 1000 Nm³. 3The standard dimensions of the liquid / gas separation volume 223, denoted L for length and H for height in Figure 2, can be between 2600 and 4200 cm and between 560 and 860 cm, respectively. The height H corresponds to the average distance between a first vertical end 2231 and a second vertical end 2232 of the separation volume 223. The length L corresponds to the average distance between a first horizontal end 2233 and a second horizontal end 2234 of the separator 22, these ends being opposite each other in a horizontal direction, said horizontal direction being perpendicular to the vertical direction. In this embodiment, the inlet portion 221 is positioned on the first horizontal end 2233, and the outlet portion 222 on the second horizontal end 2234.Thanks to this configuration of the separation volume 223, the water from the fluid falls by gravity and is collected in liquid form in a lower zone 2235 of the separation volume 223. This lower zone 2235 is delimited by the second vertical end 2232, the first horizontal end 2233, and the second horizontal end 2234. The gaseous mixture remains in an upper zone 2236 of the separation volume 223, delimited by the first vertical end 2231, the first horizontal end 2233, and the second horizontal end 2234. The outlet portion 222 is the part of the separator 22 through which the gaseous mixture exits the separator 22. It is connected to the outlet pipe 24. Thus, the gaseous mixture is discharged from the separator 22 via the outlet portion 222 and then through the outlet pipe 24, to be directed to other subsequent stages, such as conditioning stages.The outlet portion 222 and the outlet pipe 24 constitute the means of oxygen production, and it is by these means that the majority of the oxygen is produced. The electrolysis system 1 also includes a detection device 25. This detection device 25 is fluidically connected to the separator 22, specifically to the inlet portion 221 of the separator 22. The detection device 25 includes a separation element 255, which is directly connected to the inlet portion 221 of the separator 22. This separation element 255 is thus the element of the detection device 25 that is in direct contact with the inlet portion 221. It is designed to draw off a portion of the fluid from the electrolyzer 21 and direct it to the separator 22.Further details of the separation element 255 will be presented in the description of Figure 3; however, it should be noted that its role is to separate the gas mixture from the water contained in the portion of fluid taken from the inlet portion 221. The detection device 25 also includes an inlet line 251, positioned downstream of the separation element 255. The inlet line 251 carries the gas mixture, resulting from the separation of the water and this gas mixture, to the other components of the detection device 25. In addition, the detection device 25 is equipped with a gas detection line 252 and a flow acceleration means 253. The gas detection line 252 and the flow acceleration means 253 are downstream of the inlet line 251.It is therefore important to understand that the inlet line 251 is connected on one side to the separation unit 255 and on the other side, it splits into the gas detection line 252 and the flow acceleration device 253. The detection line 252 includes a gas detector 2523. This gas detector 2523 is, for example, a hydrogen detector, designed to detect low concentrations of hydrogen. More precisely, this gas detector is commonly called a "HiOD," or "Hydrogen in Oxygen Detector," thus enabling the detection of low concentrations of hydrogen in an oxygen stream, corresponding, for example, to a dihydrogen concentration in the gas mixture of less than 10%, and in particular less than 4%. In addition, the detection line 252 includes a pressure regulator 2521 and a flow control valve 2522. The pressure regulator 2521 is the element of the detection line 252 located closest to the inlet line 251.Its role is to lower the pressure of the gas mixture flowing through the detection line 252. Lowering the sample pressure reduces the relative humidity and moves it away from saturation conditions, thus limiting the risk of condensation downstream while the sample flows through the gas detector. Furthermore, this allows the ideal pressure for gas detection to be achieved. The flow control valve 2522 regulates the flow of the gas mixture to prevent damage to the detector 2523 and to ensure optimal detection. This valve is positioned between the pressure regulator 2521 and the gas detector 2523. The gas detector 2523 is the element of the detection line, among said gas detector 2523, the pressure regulator 2521 and the flow control valve 2522, furthest from the inlet line 251. The flow acceleration means 253 is a flow acceleration line comprising an inlet 2531 and an outlet 2532.Depending on the direction of gas mixture flow, the inlet 2531 of the flow acceleration means 253 is preferably positioned upstream of the gas detector 2523. Furthermore, depending on the same direction of flow, the outlet 2532 of the flow acceleration means 253 is advantageously positioned downstream of the gas detector 2523. More specifically, the inlet 2531 of the flow acceleration means is positioned between the separation element 255 and the pressure regulator 2521, thus corresponding to the point where the inlet line 251 splits into the flow acceleration means 253 and the detection line 252. This inlet of the flow acceleration means 2531 allows the flow acceleration means 253 to draw a portion of the gas mixture flowing in the inlet line 251. In this embodiment, the flow acceleration means 253 joins gas detection line 252.The flow acceleration means 253 therefore includes an outlet 2532 of the detection line 252 located where the flow acceleration means 253 joins the gas detection line 252. This outlet of the flow acceleration means 2532 thus allows the portion of the gas mixture previously sampled at the inlet of the flow acceleration means 2531 to be reintroduced into the detection line 252. By connecting at this outlet of the flow acceleration means 2532, the flow acceleration means 253 and the detection line 252 connect to a single output line 254, which thus combines the portion of the gas mixture analyzed in the detection line 252 and the portion of the gas mixture that has passed through the flow acceleration means 253. The main role of this flow acceleration means 253 is to accelerate the flow rate of the gas mixture within the device of detection 25.The flow acceleration means 253 is designed to have a high flow rate, thereby increasing the flow rate of the inlet line 251 through a suction effect and allowing the gas mixture to reach the detection line 252 more quickly by reducing its transit time. The flow acceleration means 253 thus enables a flow rate of between 1 and 2 NL / min in the detection line 252. Furthermore, the flow acceleration means 253 also accelerates the flow rate of the detection line 252 because the inlet of the flow acceleration means 2531 of the acceleration means 253 is located just before the detection line 252, and the outlet of the flow acceleration means 2532 is located just after, thus creating a suction effect. This also reduces the transit time and thus increases the detection speed.The flow acceleration means 253 includes a flow control valve 2533 for regulating the flow rate of the gas mixture circulating within the flow acceleration means 253, and thus for regulating the flow rate of the gas mixture circulating throughout the detection device 25. As mentioned previously, the gas detection line 252 and the flow acceleration means 253 join to form a common line called the outlet line 254, whose role is to discharge the gas mixture from the detection device 25. The outlet line 254 carries this gas mixture to the outlet pipe 24 to mix it with the mixture from the separator 22. The gas mixture is then directed by the outlet pipe 24 to other treatment systems. It should be noted that the invention also relates to a method for detecting a gas within a gas mixture circulating in a water electrolysis system.The water electrolysis system can, for example, be the electrolysis system 2 described in the embodiment of Figure 2. This gas detection method thus uses the detection device 25 in order to obtain a short transit time and to allow a rapid response of said detection device 25. More specifically, thanks to the flow acceleration means 253 and the positioning of the detection device 25, the gas transit time is less than 15 seconds. Figure 3 is a schematic diagram of the separation element of the detection device of the electrolysis system, according to the embodiment of Figure 2. As mentioned previously, the separation element 255 is directly connected to the inlet portion 221 of the separator 22. In this embodiment, the inlet portion 221 comprises an upper part 2211 and a lower part 2212. In this particular case, the separation element 255 is positioned on the upper part 2212.The separation element 255 includes an inlet 2552 and an outlet 2553. The inlet 2552 is connected to the upper part 2211 of the inlet portion 221 of the separator 22. The outlet 2553, on the other hand, is directly connected to the inlet line 251 of the detection device 25. The separation element 255 includes a heat exchanger 2551, said heat exchanger 2551 comprising a passage space 2555 and spheres 2554 increasing the contact surface of the heat exchanger 2551. The heat exchanger 2551 is a coaxial heat exchanger. Its role is to cool the fluid composed of water and a gas mixture in order to condense the water present in the fluid. The passage space 2555 is an empty space located in the center of the heat exchanger 2551, used to allow the passage of the gas mixture taken from the inlet portion 221.The spheres 2554 are arranged in the passage space 2555 in order to increase the contact area between the heat exchanger 2551 and the fluid, which promotes better condensation of the water present in the fluid. Thus, when a portion of fluid enters the passage space 2555 of the heat exchanger 2551, it interacts with the spheres 2554, and the water in the fluid condenses while the gas mixture does not condense and passes through the sector containing the spheres 2554. Consequently, the water condenses on the outer wall of the spheres 255, then drips by gravity towards the inlet portion 221, while the gas mixture continues its path and exits the separation element 255 through the inlet line 251 of the detection device 25. This separation element 255 therefore makes it possible to obtain a flow of water-free gas mixture, thus facilitating the detection of dihydrogen in dioxygen.Figure 4 is a schematic diagram of an electrolysis system 3 according to a second embodiment of the invention. This second embodiment is identical in all respects to the first embodiment, except for one difference: the detection device 3 includes a vent 2534 for venting the gas mixture passing through the flow acceleration means 253. More specifically, the electrolysis system 3 comprises an electrolyzer 21, a separator 22, an inlet line 23, and an outlet line 24, identical to those of the first embodiment. The electrolysis system also includes a detection device 25, which thus comprises an inlet line 251, a detection line 252, and a flow acceleration means 253. Unlike the first embodiment, the detection device 3, and more specifically the flow acceleration means 253, includes a vent 2534.In this way, the flow acceleration device 253 and the detection line 252 remain separate and thus do not join to form an outlet line. The gas mixture flowing through the flow acceleration device 253 is therefore vented through vent 2534. This gas mixture can also, instead of being vented, be routed out of the electrolysis system 2 for other uses. As for the detection line 252, it connects directly to the outlet pipe 24 of the electrolysis system 2, thus allowing the gas mixture to continue its path. However, similarly to the flow acceleration means 253 according to the second embodiment, the detection line 252 may also include a vent to vent the gas mixture circulating within it after passing through the detector 2523. This gas mixture may also be vented out of the electrolysis system by other means to serve other applications.The present invention thus proposes an electrolysis system comprising an electrolyzer, a gas / liquid separator for a fluid from the electrolyzer, and a gas detection device. The electrolysis system and its components are arranged to minimize gas transit time, thereby enabling safety functions to respond before any hazardous situation arises. However, the present invention is not limited to the means and configurations described and illustrated herein, and also extends to any equivalent means and configuration, as well as any technically feasible combination thereof.

Claims

CLAIMS:

1. Water electrolysis system (2) comprising an electrolyzer with electrolytic membranes (21) and a separator (22) for carrying out liquid / gas separation of a fluid supplied by the electrolyzer (21), the separator (22) comprising an inlet portion (221) connected to the electrolyzer (21), a liquid / gas separation volume (223) and an outlet portion (222) through which a gas mixture exits, characterized in that the water electrolysis system (2) comprises a detection device (25) for a gas contained in the gas mixture, said detection device (25) being connected to the inlet portion (221) of the separator (22).

2. Water electrolysis system (2) according to claim 1, wherein the detection device (25) comprises at least one gas detection line (252) and at least one flow acceleration means (253) accelerating the flow of the gas mixture circulating in the gas detection line (252). 3.A water electrolysis system (2) according to claim 2, wherein the detection device (25) comprises a liquid-gas separator (255), the separator (255) being connected to the inlet portion (221) of the separator (22).

4. A water electrolysis system (2) according to claim 3, wherein the separator (255) comprises at least one heat exchanger (2551) having spheres (25511) increasing the contact surface with the fluid.

5. A water electrolysis system (2) according to any one of claims 2 to 4, wherein the detection line (252) comprises at least one pressure regulator (2521), a flow control valve (2522), and a detector (2523) of said gas.

6. Water electrolysis system (2) according to claim 5, wherein the flow control valve (2522) is disposed between the pressure regulator (2521) and the detector (2523). 7.Water electrolysis system (2) according to any one of claims 5 or 6, wherein the flow acceleration means (253) comprises an inlet (2531) connected to the detection line (252) between the separation member (255) and the regulator (2521).

8. A water electrolysis system (2) according to any one of claims 2 to 7, wherein the flow acceleration means (253) comprises a flow control valve (2533).

9. A water electrolysis system (2) according to any one of claims 2 to 8, wherein the detection line (252) is intended to detect the presence of dihydrogen in a gas mixture containing predominantly dioxygen.

10. A water electrolysis system (2) according to any one of claims 2 to 9, wherein the flow acceleration means (253) is configured so that the flow rate of the detection line (252) is between 1 and 2 NL / min.

11. Method for detecting a gas within a gas mixture circulating in a water electrolysis system (2) according to any one of claims 1 to 10, during which the transit time of the gas is less than 15 seconds.

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