Electrolysis system including a rapid gas detection device

Abstract

Electrolysis system comprising a rapid gas detection device. The invention relates to a water electrolysis system (2) comprising an electrolyzer with electrolytic membranes (21) and a separator (22) for performing liquid / gas separation of a fluid supplied by the electrolyzer (21). The separator (22) comprises an inlet portion (221) connected to the electrolyzer (21), a liquid / gas separation volume (223), and an outlet portion (22) through which a gaseous mixture exits. The system is characterized in that the water electrolysis system (2) comprises a detection device (25) for a gas contained in the gaseous mixture, said detection device (25) being connected to the inlet portion (221) of the separator (22). (Figure 2)

Description

Title of the invention: Electrolysis system comprising a rapid gas detection device

[0001] The present invention relates to the field of water electrolysis and more particularly to the analysis of gases present in the flows from electrolyzers.

[0002] Water electrolysis is a technique that involves 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.

[0003] 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. In addition, oxygen 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.

[0004] The electrolysis of water thus makes it possible to produce, on the one hand, a stream composed of a first gas and water, and on the other hand, a stream composed of a second gas and water. In order to obtain these pure gases, the first gas and the second gas must therefore be separated from the water contained in their respective streams. This separation is conventionally 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 accumulating at the bottom of the separator while the first or second gas rises to the top of the separator.

[0005] 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 the production of 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 dioxygen and the second gas is dihydrogen, there is a particular risk of explosion when the concentration of dihydrogen in the dioxygen exceeds 4%.

[0006] To counter the risk of explosion, the separators are equipped with analysis 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 analysis systems are designed to stop electrolysis if a critical level of 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 the subsequent steps to secure the installation. The limit threshold of the first gas within the second gas or the limit threshold of the second gas within the first gas may then be exceeded before the analysis system can detect it.

[0007] This problem is exacerbated in industrialized contexts where electrolyzers are designed to operate over a wide range of capacities. Analytical systems may then fail to provide sufficiently rapid responses, particularly when the electrolyzers operate 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.

[0008] If the detection is too slow, the system may not intervene before the concentration of the first gas or the second gas reaches the critical threshold, thus posing a significant risk of contamination of the first gas or the second gas by the second gas or the first gas and thereby increasing the risk of explosion.

[0009] 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 of this gas for the purpose of its analysis. This reduced transit time thus helps to avoid dangerous situations related to high levels of said gas.

[0010] The present invention thus has as its main object a water electrolysis system comprising an electrolyzer with electrolytic membranes and a separator intended to carry out a liquid / gas separation of a fluid supplied by the electrolyzer, the separator comprising an inlet portion connected to the electrolyzer, a liquid / gas separation volume and an outlet portion through which a gaseous mixture exits, characterized in that the water electrolysis system comprises a device for detecting a gas contained in the gaseous mixture, said detection device being connected to the inlet portion of the separator.

[0011] The electrolyzer is therefore an electrolytic membrane electrolyzer. 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, produces 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.

[0012] On the cathode side, the electrolyzer produces a mixture of dihydrogen and water. On the anode side, it produces a fluid comprising water and a gaseous mixture, this gaseous mixture being mainly composed of dioxygen and, in smaller quantities, dihydrogen.

[0013] The separator is designed to separate the gas mixture and water from the fluid produced by the electrolyzer anode. The inlet portion of the separator allows the fluid, which has been supplied 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 volume, while the gas mixture accumulates in the upper part. The outlet portion allows the gas mixture to be discharged from the separator.

[0014] Regarding the detection device, it is connected to the inlet portion of the separator. This means that it is directly connected to the inlet portion; that is, there are no other intermediate elements between the detection device and the inlet portion, apart from a fluid transport conduit. 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 present in the gas mixture to be detected before it passes through the separator. Consequently, the transit time is very short and leads to very rapid detection of the gas present in the gas mixture. This process therefore allows for a rapid response to excessively high gas concentrations, even if the installation is operating at a low flow rate.

[0015] It should be noted that the transit time represents the time required for the gas to be detected by the detection device after it has been produced by the electrolyzer.

[0016] According to an optional feature of the invention, the detection device includes at least one gas detection line and at least one flow acceleration means accelerating the flow of the gas mixture circulating in the gas detection line.

[0017] The gas detection line is an element of the detection device comprising a means designed to detect gas in the gas mixture.

[0018] The flow acceleration means accelerates 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 acceleration further reduces the transit time, thus enabling a rapid response to the gas concentration measured by the detection device.

[0019] The flow acceleration means is generally an acceleration line that draws a portion of the gas mixture passing through the detection device. Such acceleration increases the overall velocity of the gas mixture flowing through the detection device.

[0020] According to an optional feature of the invention, the detection device includes a liquid and gas separation element, the separation element being connected to the inlet portion of the separator.

[0021] The separation element is designed to separate the gaseous mixture from the water of the fluid taken from the inlet portion of the separator.

[0022] It should be understood that the separating element is connected directly 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 separating element is positioned in this way so that only the gas mixture flows through the rest of the detection device. This optimizes detection and makes it possible to determine a precise gas concentration by preventing the presence of water from the fluid.

[0023] According to an optional feature of the invention, the separation element comprises at least one heat exchanger containing spheres which increase the contact area with the fluid.

[0024] 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 incorporates 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 gaseous mixture is drawn into the rest of the sensing device.

[0025] According to an optional feature of the invention, the detection line includes at least one pressure regulator, a flow control valve and a detector of said gas.

[0026] The regulator allows the pressure of the gas mixture to be lowered so that, when the gas mixture reaches the detector, the latter can correctly measure the gas without being damaged.

[0027] Similarly, the flow control valve allows the flow of the gas mixture to be controlled so that the detector can perform an optimal measurement of the gas contained in the mixture and avoid damage.

[0028] The detector can, for example, be used to detect dihydrogen in a mixture containing mostly dioxygen and a small amount of dihydrogen, allowing it to capture low levels of dihydrogen. More specifically, it can be designed to detect if the dihydrogen concentration exceeds 2% of the gas mixture in order to shut down the electrolysis system and prevent a potentially explosive situation when the concentration reaches 4%.

[0029] According to an optional feature of the invention, the flow control valve is arranged between the pressure regulator and the detector.

[0030] 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 allows the pressure to be reduced first and the flow rate to be regulated, so that the gas mixture reaches the detector with the appropriate pressure and flow rate.

[0031] According to an optional feature of the invention, the flow acceleration means includes an inlet connected to the detection line and positioned between the separating element and the pressure regulator.

[0032] When the inlet of the flow acceleration means is connected to the detection line, the gas mixture flowing in the detection device is separated into two parts: a first part flows in the detection line and a second part passes through the inlet of the flow acceleration means. The point where the gas mixture is thus divided is therefore the inlet of the flow acceleration means, and it is thus located between the separator and the pressure regulator.

[0033] The flow acceleration means may optionally include an outlet connected to the detection line. This outlet is connected so as to be 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 acceleration means rejoins the portion of the gas mixture flowing in the detection line. This configuration creates a suction effect in the detection line, further reducing the transit time within the detection device.

[0034] After circulating in the flow acceleration means, the gas mixture can thus either join the detection line when the flow acceleration means includes an outlet connected to this detection line, or be evacuated through a vent.

[0035] The gas mixture flowing in the detection line can also be vented through a vent. Thus, when the gas mixture that has flowed through the flow acceleration means rejoins that which has flowed in the detection line, the resulting mixture can either rejoin the gas mixture from the separator or be vented through a single vent.

[0036] According to an optional feature of the invention, the flow acceleration means includes a flow control valve.

[0037] This flow control valve allows the flow rate of the gas mixture in the flow acceleration means to be controlled. Thus, by adjusting the flow rate of the gas mixture in the acceleration means, the flow rate of the gas mixture in the detection device can be increased or decreased, thereby controlling the gas transit time.

[0038] According to an optional feature of the invention, the detection line is intended to detect the presence of dihydrogen within a gaseous mixture containing at least dioxygen.

[0039] In this case, the fluid is composed of water and a gaseous mixture consisting mainly 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 level of dihydrogen starting at 2% and, subsequently, trigger the shutdown of the electrolysis system.

[0040] 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.

[0041] The flow rate of the detection line is influenced in particular by the setting of the control valve of the acceleration means, by the setting of the control valve of the detection line, as well as by the pressure upstream and downstream of the flow acceleration means.

[0042] By way of example, the acceleration means is set to a flow rate approximately 10 times higher than the flow rate that is to be obtained in the detection line, for example a flow rate of the acceleration means of 11 NL / min for a flow rate of the detection line between 1 and 2 NL / min.

[0043] According to another aspect, the invention relates to a method for detecting a gas within a gas mixture circulating in a water electrolysis system as described in this document, during which the transit time of the gas is less than 15 seconds.

[0044] Thanks to this particularly short transit time, the process allows for a rapid response to urgent situations where the gas level would increase rapidly. This prevents the gas level from becoming significant before the detection device has detected an anomaly.

[0045] In the case of dihydrogen in dioxygen, the explosive limit is set at 4% and the electrolysis system stops if the concentration exceeds 2%. Thanks to this rapid transit time, it is ensured that the measured concentration corresponds to the actual concentration within the separator.

[0046] 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:

[0047] [Fig-1] is a schematic diagram of an electrolysis system according to the prior art.

[0048] [Fig.2] is a schematic diagram of an electrolysis system according to a first mode of the realization of the invention.

[0049] [Fig.3] is a schematic diagram of a separation element of a detection device of the electrolysis system according to the embodiment of [Fig.2].

[0050] [Fig.4] is a schematic diagram of an electrolysis system according to a second embodiment of the invention.

[0051] The features and variants of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants 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.

[0052] In the figures, the elements common to several figures retain the same reference.

[0053] The [Fig.1] is a schematic diagram of an electrolysis system 1 according to the prior art.

[0054] In the prior art, electrolysis systems 1 may include an electrolyzer 11, a gas / liquid separator 12, and an analysis unit 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 then being sent to the separator 12. This fluid is conveyed to the separator 12 via an inlet pipe 13.

[0055] 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. Gravity 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 top of the separator 12. The gas mixture in the upper part of the separator 12 is then discharged from the separator 12 through an outlet pipe 14.

[0056] As mentioned earlier, when the first gas is dioxygen and the second gas is dihydrogen, it is necessary to detect the dihydrogen present in the dioxygen, since a level of 4% dihydrogen in the gas mixture leads to a risk of major explosion by reaction between dioxygen and dihydrogen.

[0057] For this purpose, the prior art electrolysis system 1 comprises an analysis unit 15, enabling the detection of the concentration of dihydrogen in dioxygen. The analysis unit 15 is connected to the outlet line 14 and recovers the gas mixture from the separator for analysis.

[0058] If the concentration of dihydrogen is greater than 2%, the analysis assembly 15 sends stop signals to the electrolysis system 1 to avoid any explosive situation, i.e. a concentration of dihydrogen greater than 4%.

[0059] The problem with the technology used in the prior art lies in the significant transit time. Indeed, the hydrogen concentration is measured only after the hydrogen has passed through the separator 12. Consequently, the measured concentration does not reflect the actual hydrogen concentration in the separator 12. For example, a detection of 2% could actually correspond to a concentration greater than 4% in the separator, which is above the explosive threshold. Due to the industrialization of water electrolysis processes, the dimensions of separators tend to increase and their range of applications to become broader, which exacerbates these problems. In large separators, and especially when using a low flow rate, the transit time is increased, so the analysis assembly 15 is unsatisfactory and cannot guarantee the absence of explosion risk.

[0060] The [Fig.2] is a schematic diagram of an electrolysis system 2 according to a first embodiment of the invention.

[0061] The electrolysis system 2 includes at least one electrolyzer 21, a separator 22, an inlet pipe 23, an outlet pipe 24 and a detection device 25.

[0062] 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. Electrolyzers with electrolytic membranes, such as electrolyzer 21, are part of the so-called polymer electrolyte technology (known by the acronym PEM, which stands for proton-exchange membrane or polymer electrolyte membrane). Such an electrolytic membrane is arranged between a cathode and an anode. The electrolytic membrane is permeable to protons but electrically insulating, that is, impermeable to electrons.

[0063] The electrolyzer 21, through which a flow of water passes, applies an electric current such that dioxygen and hydrogen ions are formed from water at the anode. The hydrogen ions then migrate, via the electric current, to the cathode through the electrolytic membrane and are formed there as dihydrogen. Thus, with this technology, one side of the membrane is used for the production of dioxygen and the other side for the production of dihydrogen. The dihydrogen is then recovered for processing, as is the dioxygen on its side. The electrolysis system 2 is dedicated, by way of example, to the processing of the dioxygen produced by this technology.

[0064] The electrolyzer 21 delivers a fluid comprising a gaseous mixture and water. This fluid is exited from the anode side and must be treated to extract only The gaseous mixture. This gaseous mixture, mainly composed of dioxygen, may contain small quantities of other gases, such as dihydrogen. Indeed, during electrolysis, hydrogen ions can remain on the anode side and form dihydrogen.

[0065] This fluid is conveyed from the electrolyzer 21 to the separator 22 via the inlet pipe 23.

[0066] The separator 22 is in the form of a large tank. This separator 22 comprises an inlet portion 221, an outlet portion 222, and a liquid / gas separation volume 223 for separating the gas mixture from the water.

[0067] 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 may, 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.

[0068] 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.

[0069] By way of example, for an electrolyzer with a capacity of 1000 Nm3 / h, the standard dimensions of the liquid / gas separation volume 223, noted L for length and H for height on [Fig.2], can be respectively between 2600 and 4200 cm and between 560 and 860 cm.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The outlet portion 222 is the part of the separator 22 through which the gas mixture exits the separator 22. It is connected to the outlet line 24. Thus, the gas mixture is discharged from the separator 22 via the outlet portion 222 and then through the outlet line 24, to be directed to other subsequent stages, such as conditioning stages. The outlet portion 222 and the outlet line 24 constitute the means for producing dioxygen, and it is by these means that the majority of the dioxygen is produced.

[0074] The electrolysis system 1 also includes a detection device 25. This detection device 25 is fluidly connected to the separator 22, in particular to the inlet portion 221 of the separator 22.

[0075] The detection device 25 includes a separating element 255, which is directly connected to the inlet portion 221 of the separator 22. This separating 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 a portion of the fluid from the electrolyzer 21 and directed to the separator 22. Further details of the separating element 255 will be presented in the description of [Fig. 3]; however, it should be noted that its role is to separate the gas mixture from the water contained in the portion of fluid drawn from the inlet portion 221.

[0076] The detection device 25 also includes an inlet line 251, positioned downstream of the separation member 255. The inlet line 251 carries the gaseous mixture, resulting from the separation of the water and this gaseous mixture, to the other components of the detection device 25.

[0077] 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 should therefore be understood that the inlet line 251 is connected on one side to the separation element 255 and on the other, it divides into the gas detection line 252 and the flow acceleration means 253.

[0078] The detection line 252 includes a pressure regulator 2521, a flow control valve 2522, and a gas detector 2523. The pressure regulator 2521 is the component 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 said detection line 252. Lowering the sample pressure reduces the relative humidity and moves away from saturation conditions, thus limiting the risk of condensation downstream while the sample flows through the gas detector. Furthermore, this allows an ideal pressure for gas detection to be achieved.

[0079] The flow control valve 2522 controls the flow rate of the gas mixture to prevent damage to the detector 2523 and to allow for optimal detection. This valve is positioned between the pressure regulator 2521 and the gas detector 2523.

[0080] The 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. The gas detector 2523 is the element of the detection line furthest from the inlet line 251.

[0081] The flow acceleration means 253 is a flow acceleration line comprising an inlet 2531 and an outlet 2532. The inlet 2531 of the flow acceleration means is positioned between the separator 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 sensing 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.

[0082] In this embodiment, the flow acceleration means 253 connects to the gas detection line 252. The flow acceleration means 253 therefore includes an outlet 2532 of the detection line 252 located at the point where the flow acceleration means 253 connects to 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 outlet 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 passed through the flow acceleration means. 253.

[0083] The main role of this flow acceleration means 253 is to accelerate the flow of gas mixture within the detection device 25. The flow acceleration means 253 is thus designed to have a high flow rate, thereby increasing the flow rate of the inlet line 251 by a suction phenomenon and allowing the gas mixture to reach the detection line 252 more quickly by reducing its transit time.

[0084] The flow acceleration means 253 thus makes it possible to obtain a flow rate of the detection line 252 between 1 and 2 NL / min.

[0085] Furthermore, the flow acceleration means 253 also accelerates the flow rate of the detection line 252 since 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 means The flow rate acceleration at 2532, immediately following, creates a suction effect. This also reduces transit time and thus increases detection speed.

[0086] The flow acceleration means 253 includes a flow control valve 2533 allowing the flow of the gas mixture circulating in the flow acceleration means 253 to be regulated, and thus allowing the flow of the gas mixture circulating in the entire detection device 25 to be regulated.

[0087] 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 evacuate 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 that from the separator 22. The gas mixture is then directed by the outlet pipe 24 to other processing systems.

[0088] It should be emphasized that the invention also relates to a method for detecting a gas within a gas mixture circulating in a water electrolysis system. Said water electrolysis system may, for example, be the electrolysis system 2 described in the embodiment of [Fig. 2].

[0089] This method for detecting a gas 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 transit time of the gas is less than 15 seconds.

[0090] The [Fig.3] is a schematic diagram of the separation element of the detection device of the electrolysis system, according to the embodiment of the [Fig.2].

[0091] As mentioned previously, the separating member 255 is connected directly 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 the present case, the separating member 255 is positioned on the upper part 2212.

[0092] The separating element 255 comprises 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.

[0093] The separating element 255 comprises 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.

[0094] The passage space 2555 is an empty space located in the center of the heat exchanger 2551, used to allow the passage of the gaseous mixture taken from the inlet portion 221.

[0095] 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.

[0096] 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. As a result, 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 member 255 through the inlet line 251 of the detection device 25.

[0097] This separation element 255 therefore makes it possible to obtain a water-free gas mixture flow, thus facilitating the detection of dihydrogen in dioxygen.

[0098] The [Fig.4] is a schematic diagram of an electrolysis system 3 according to a second embodiment of the invention.

[0099] This second embodiment is identical in every respect to the first embodiment, except for one difference which lies in the fact that the detection device 3 includes a vent 2534 allowing the gas mixture passing through the flow acceleration means 253 to be evacuated.

[0100] 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.

[0101] 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 means 253 and the detection line 252 remain separate and thus do not join to form an outlet line. The gas mixture circulating in the flow acceleration means 253 is thus vented through the vent 2534. This gas mixture can also, instead of being vented, be routed out of the electrolysis system 2 for other uses.

[0102] Regarding 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 evacuate the gas mixture circulating within it after passing through the detector 2523. This gas mixture can also be evacuated from the electrolysis system by other means to serve other applications.

[0103] 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 in such a way as to minimize the gas transit time, in order to allow the safety functions to respond before any hazardous situation arises.

[0104] The present invention is not limited to the means and configurations described and illustrated herein and extends also to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

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 flowing in the gas detection line (252).

3. Water electrolysis system (2) according to claim 2, wherein the detection device (25) comprises a liquid and gas separation member (255), the separation member (255) being connected to the inlet portion (221) of the separator (22).

4. Water electrolysis system (2) according to claim 3, wherein the separation member (255) comprises at least one heat exchanger (2551) having spheres (25511) increasing the contact area with the fluid.

5. 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 separating member (255) and the regulator (2521).

8. 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. 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 within a gaseous mixture containing mostly dioxygen.

10. 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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