Hydrogen production facility comprising hydrogen recirculation assembly

Abstract

The invention relates to a hydrogen production facility (222) comprising a hydrogen recirculation assembly (100, 200). The hydrogen production facility (222) comprises at least one main compressor (226, 426) which is fluidically connected to at least one electrolyzer (224, 424) via a main hydrogen flow fluid network (232), wherein the hydrogen recirculation assembly (100, 200) comprises a first fluid inlet (102, 202) which can be connected to a first hydrogen leakage point (240) of the hydrogen production facility (222) and which is connected to at least one collecting container (106, 206) of the hydrogen recirculation assembly (100, 200) via at least one first fluid connection (110, 210); a second fluid inlet (104, 204) which can be connected to a second hydrogen leakage point (242) of the hydrogen production facility (222) and which is connected to the collecting container (106, 206) via at least one second fluid connection (112, 212); at least one recirculation compressor (108, 208) which is connected to the collecting container (106, 206) via at least one third fluid connection (114), and at least one first fluid outlet (118, 218) which can be connected to a main hydrogen flow fluid network (232) of the hydrogen production facility (222) and which is connected to the recirculation compressor (108, 208) via at least one fourth fluid connection (116).

Description

[0001] Hydrogen production plant with hydrogen recirculation system

[0002] The invention relates to a hydrogen recirculation arrangement for a hydrogen production plant, wherein the hydrogen production plant comprises at least one main compressor fluidly connected to at least one electrolyzer via a main hydrogen flow fluid network. Furthermore, the invention relates to a hydrogen production plant and a hydrogen recirculation method.

[0003] Hydrogen, especially hydrogen gas, is increasingly being used as an energy carrier these days. Hydrogen can be produced from water through electrolysis. Electrolysis involves the application of electrical energy or power to force a redox reaction, thereby generating hydrogen.

[0004] The generated or produced hydrogen can then be stored, for example, in suitable storage facilities and / or fed into a hydrogen network or pipeline network. Alternatively, the hydrogen can also be converted into methane, which can then be stored and / or fed into a corresponding pipeline network. The stored hydrogen (or methane) can, for example, be converted into electrical energy, for example, using a hydrogen fuel cell (also known as reverse electrolysis) or by combustion in a gas-fired power plant. It is understood that the hydrogen and / or methane produced can also be used for other chemical processes.

[0005] Preferably, electrical energy from so-called renewable energies (e.g., hydropower, photovoltaics, wind power, etc.) can be provided for the electrical energy supply. A hydrogen production plant comprises a plurality of production devices. In particular, at least one electrolyzer can be fluidly connected to a main compressor of the hydrogen production plant via a main hydrogen flow fluid network.

[0006] A hydrogen production plant typically has several known hydrogen loss points. In particular, at various points in a hydrogen production plant, streams of largely pure hydrogen occur whose pressure is below the pressure of the electrolysis process (especially the operating pressure of the raw hydrogen).

[0007] In particular, it has been recognized that, for example, the following hydrogen loss points can exist in a hydrogen production plant:

[0008] 1. Main compressor of the hydrogen production plant: Cracked gas losses in the main compressor, particularly in the form of at least one piston compressor. So-called dry gas seals are generally used in a main compressor. The reason for this is primarily that oil-lubricated pistons in a main compressor would contaminate the produced hydrogen with oil. Multiple seal packings on the piston rods can reduce hydrogen losses from the interior towards the center, for example at 30-70 bar. Nitrogen can be added from the outside as a barrier gas, but this must be removed separately with a hydrogen content. In particular, it has been found that hydrogen losses in the form of cracked gas losses in the center amount to between 1% and 2% of the production quantity per compressor stage and increase particularly as the seal packings age.

[0009] 2. Hydrogen analysis device of the hydrogen production plant: Hydrogen losses occur at the at least one hydrogen analysis device after the measurement. At least one such hydrogen analysis device can be provided for each electrolysis module of the electrolyzer. The hydrogen analysis device can include a bypass around the actual measuring device. The larger the current through this bypass, the smaller the time delay of the measured value compared to the actual value within the electrolysis module or the process device. Increasing the bypass current in conjunction with its recirculation thus enables a reduction in the measurement delay without additional product loss.

[0010] 3. Low-pressure separators in the hydrogen production plant: Hydrogen losses also occur in low-pressure separators. In a low-pressure separator, the liquid phase from the high-pressure separator is depressurized to a lower pressure to remove further hydrogen from the water phase. This is particularly necessary because some of this water can later reach the oxygen side. For safety reasons, dissolved hydrogen should be as low as possible here. On the oxygen side, in particular, the maximum hydrogen content in the oxygen must be 2%, as this is half the lower explosion protection limit. Low-pressure separators typically operate at an operating pressure between 3 barg and 8 barg.

[0011] 4. Drying device of the hydrogen production plant: Furthermore, hydrogen regeneration gas losses can occur during drying by adsorption. Regeneration of the adsorber bed occurs particularly at higher temperatures (so-called TSA (temperature swing adsorption)) and / or lower pressure (so-called PSA). This also leads to hydrogen losses.

[0012] It is known from the state of the art to collect these hydrogen losses for safety reasons and release them into the environment via a fluid network and vents. However, this state-of-the-art solution is problematic from an environmental perspective. For example, hydrogen has a greenhouse effect. Therefore, one solution discussed in the state of the art is to burn the lost hydrogen in a flare in the future. However, in a flare, this lost hydrogen cannot be utilized as a product, and combustion generates further air emissions. As previously described and recognized, the total hydrogen losses in a state-of-the-art hydrogen production plant can amount to more than 3%.

[0013] Therefore, the object of the invention is to provide a possibility with which the disadvantages of the prior art are at least reduced and, in particular, a hydrogen production plant can be operated with increased efficiency.

[0014] According to a first aspect of the invention, the object is achieved by a hydrogen recirculation arrangement according to claim 1 for a hydrogen production plant. The hydrogen production plant comprises at least one main compressor fluidly connected to at least one electrolyzer via a main hydrogen flow fluid network. The hydrogen recirculation arrangement comprises a first fluid inlet connectable to a first hydrogen loss point of the hydrogen production plant. The first fluid inlet is connected to at least one collecting tank of the hydrogen recirculation arrangement via at least one first fluid connection. The hydrogen recirculation arrangement comprises a second fluid inlet connectable to a second hydrogen loss point of the hydrogen production plant. The second fluid inlet is connected to the collecting tank via at least one second fluid connection.The hydrogen recirculation arrangement comprises at least one recirculation compressor connected to the collection tank via at least one third fluid connection. The hydrogen recirculation arrangement comprises at least one first fluid outlet connectable to a main hydrogen flow fluid network of the hydrogen production plant. The first fluid outlet is connected to the recirculation compressor via at least one fourth fluid connection.

[0015] A further aspect of the invention is a hydrogen production plant. The hydrogen production plant comprises at least one main compressor fluidically connected to at least one electrolyzer of the hydrogen production plant. The hydrogen production plant comprises at least one first hydrogen loss point and one second hydrogen loss point. The hydrogen production plant comprises a hydrogen recirculation arrangement as described above. The first fluid inlet of the hydrogen recirculation arrangement is connected to the first hydrogen loss point, and the second fluid inlet of the hydrogen recirculation arrangement is connected to the second hydrogen loss point. In particular, the first fluid outlet is fluidically connected to a main hydrogen flow fluid network of the hydrogen production plant.

[0016] By providing, in contrast to the prior art, a hydrogen recirculation arrangement for a hydrogen production plant, which recirculates the lost hydrogen escaping from at least two hydrogen loss points of the hydrogen production plant back into the hydrogen production plant, the disadvantages of the prior art are at least reduced and, in particular, operation of the hydrogen production plant with increased efficiency is enabled. In particular, it has been recognized that the lost hydrogen of the hydrogen production plant can be recirculated or recycled by means of a collection tank and a recirculation compressor. The hydrogen production plant according to the invention is preferably an onshore hydrogen production plant, but can also be an offshore hydrogen production plant.

[0017] The hydrogen production plant according to the invention comprises at least one electrolyzer. The electrolyzer can comprise at least one electrolysis module, in particular an electrolyzer stack, for example a proton exchange membrane (PEM) electrolyzer. It is understood that in variants of the invention, the at least one electrolyzer can alternatively or additionally be an electrolyzer of a different type, such as an alkaline water electrolyzer (AWE), high-temperature electrolyzer, or the like.

[0018] Furthermore, the hydrogen production plant according to the invention comprises at least one main compressor or main compressor. A main compressor can comprise at least one compressor module, preferably a plurality n of compressor modules or compression modules, where n is a natural number, for example between 2 and 10, preferably between 2 and 5. The at least one compressor module can be arranged in a compressor housing, in particular in the form of a compressor building. A compressor module can be configured to compress the hydrogen generated (and in particular processed) by the electrolyzer, in particular the dried hydrogen. A compressor module can comprise at least one hydrogen compressor, in particular a piston compressor.

[0019] The hydrogen production plant can preferably comprise at least one main hydrogen flow fluid network with at least one fluid connection (e.g., a fluid pipe or fluid line). The main compressor is fluidly connected to the electrolyzer via the main hydrogen flow fluid network, for example (directly or indirectly) via one or more fluid connections. The hydrogen production plant has at least two hydrogen loss points. A hydrogen loss point refers, in particular, to a location in the hydrogen production plant at which (unpreventable) hydrogen escapes from a specific component of the hydrogen production plant during (normal) operation of the hydrogen production plant (continuously or discontinuously). The escaped hydrogen, also referred to as lost hydrogen, can be captured or collected (in a known manner, in particular by the hydrogen loss point).

[0020] The hydrogen return arrangement (also referred to as recycling system) is particularly designed to return or recycle lost hydrogen from the hydrogen production plant into the hydrogen production plant.

[0021] According to the invention, the hydrogen recirculation arrangement comprises at least two fluid inlets, in particular at least one first fluid inlet and one second fluid inlet. Each fluid inlet is configured, in particular, for fluid coupling to a respective hydrogen loss point. In other words, the lost hydrogen (escaped from the hydrogen production plant) enters the hydrogen recirculation arrangement, in particular via a fluid inlet, thus flowing, in particular, into a recirculation hydrogen flow fluid network having, in particular, a plurality of fluid connections.

[0022] The first fluid inlet is fluidically connected (directly or indirectly) to at least one collecting container via at least one first fluid connection (e.g., a fluid pipe). The second fluid inlet is fluidically connected (directly or indirectly) to the collecting container via at least one second fluid connection (e.g., a fluid pipe).

[0023] The hydrogen recirculation arrangement comprises at least one collecting tank.

[0024] The collection tank in the form of a hydrogen collection tank is particularly designed to collect or (temporarily) store the lost hydrogen. In particular, due to a pressure difference between the operating pressure in the collection tank and the respective operating pressure at the respective hydrogen loss points, the lost hydrogen can flow (automatically) from a respective hydrogen loss point via the respective fluid inlet and the respective fluid connection into the collection tank.

[0025] Furthermore, the hydrogen recirculation arrangement comprises at least one recirculation compressor. The recirculation compressor may comprise at least one compressor module. The at least one compressor module may be arranged in a compressor housing. A compressor module of the recirculation compressor may be configured to compress the lost hydrogen collected in the collection container. A compressor module of the recirculation compressor may comprise at least one hydrogen compressor (in particular a piston compressor).

[0026] The recirculation compressor is fluidically connected to the recirculation compressor in particular via the recirculation hydrogen flow fluid network, in particular at least a third fluid connection (e.g. a fluid pipe).

[0027] The hydrogen recirculation arrangement according to the invention comprises at least one first fluid outlet. The first fluid outlet is configured to feed the lost hydrogen compressed by the recirculation compressor into the hydrogen production plant, in particular into the main hydrogen flow fluid network of the hydrogen production plant.

[0028] In particular, the first fluid outlet is configured for fluidly coupling the recirculation hydrogen flow fluid network to the main hydrogen flow fluid network. The first fluid outlet is fluidly connected to the main hydrogen flow fluid network, in particular via the recirculation hydrogen flow fluid network, in particular at least one fourth fluid connection (e.g., a fluid pipe).

[0029] According to a preferred embodiment of the hydrogen recirculation arrangement according to the invention, the first fluid inlet and / or the first fluid connection can comprise at least one first backflow prevention module. The at least one first backflow prevention module can, in particular, be a pressure-maintaining valve, a check valve, and / or a shut-off valve. It is understood that other backflow prevention modules can also be provided in variants of the invention.

[0030] Alternatively or additionally, the second fluid inlet and / or the second fluid connection can comprise at least one second backflow prevention module. The at least one second backflow prevention module can, in particular, be a pressure-maintaining valve, a check valve, and / or a shut-off valve. It is understood that other backflow prevention modules can also be provided in variants of the invention.

[0031] Preferably, each fluid inlet and / or the respective fluid connection of the hydrogen recirculation arrangement connected thereto can comprise at least one backflow prevention module. A backflow prevention module is particularly configured to block a backflow of the lost hydrogen, in particular from the collection container via the respective fluid connection and the respective fluid inlet into the respective loss point.

[0032] A pressure control valve or a PCV (pressure control valve) (e.g. a spring-loaded or actively controlled valve) (in the fluid connection from the loss point to the collection container) is in particular designed to maintain the operating pressure on the side of the hydrogen loss point at a substantially constant pressure. Alternatively or additionally, a pressure control valve or a PCV (pressure control valve) (e.g. spring-loaded or actively controlled valves) (in the fluid connection from the loss point to the collection container) is in particular designed to limit the operating pressure on the side of the collection container to a predetermined maximum pressure limit. If a shut-off valve is provided (in the fluid connection from the loss point to the collection container), a valve for blowing out can be opened upstream of the loss point, for example automatically by a control system when the respective shut-off valve is closed or indirectly via the pressure increase.

[0033] In particular, it has been recognized here that the pressure at the at least two hydrogen loss points should be maintained within a (respective) defined pressure range. The reason for this is, in particular, that no process-related disruptions due to pressure fluctuations and / or backflow from the hydrogen recirculation arrangement occur at the at least two hydrogen loss points. As described, backflow of lost hydrogen can be achieved, in particular, by the measures described above. The hydrogen recirculation arrangement can be operated in a particularly safe manner.

[0034] Alternatively or additionally, the first fluid outlet may comprise at least one backflow prevention module (as previously described).

[0035] According to a preferred embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise at least one hydrogen analysis device. The hydrogen analysis device can be configured to analyze hydrogen. In particular, a partial flow of the lost hydrogen from the recirculation hydrogen flow fluid network can be conducted to the hydrogen analysis device. The at least one hydrogen analysis device is configured, in particular, to determine the composition of the lost hydrogen or of the fluid flow flowing through the hydrogen recirculation arrangement. In particular, the at least one hydrogen analysis device can be configured to (approximately) determine the nitrogen concentration in the lost hydrogen.Preferably, in addition, the at least one hydrogen analysis device can be configured to (approximately) determine the oxygen concentration in the lost hydrogen.

[0036] For example, the hydrogen analysis device can comprise or form at least one thermal conductivity analyzer. The thermal conductivity analyzer can be configured, in particular, to measure the nitrogen and oxygen in the lost hydrogen. Alternatively or additionally, the hydrogen analysis device can comprise or form at least one fuel cell sensor. The fuel cell sensor can be configured to measure the oxygen concentration in the lost hydrogen.

[0037] It is understood that in variants of the invention, other devices can also be used, such as a so-called thermo-paramagnetic oxygen sensor (e.g. Michell XTP501), optically operating sensors and / or gas chromatographs.

[0038] According to a further embodiment, the at least one hydrogen analysis device can be connectable or connected to the fourth fluid connection at a fluid connection point (for example, via a controllable valve). Preferably, the hydrogen recirculation arrangement can comprise at least one second fluid outlet (in particular comprising an outlet valve) arranged in the fourth fluid connection downstream of the fluid connection point of the hydrogen analysis device in the flow direction. The second fluid outlet can be controllable, at least based on an analysis result of the hydrogen analysis device. In particular, according to a preferred embodiment of the hydrogen recirculation arrangement according to the invention, at least one contamination criterion can be predetermined, for example, stored in the hydrogen analysis device.The contamination criterion can in particular be selected such that the fulfillment of the contamination criterion (e.g. concentration limits, such as a maximum permissible oxygen concentration value and / or a maximum permissible nitrogen concentration value) indicates that the lost hydrogen is contaminated with other substances (in particular oxygen and / or nitrogen) to such an extent that refeeding should be omitted.

[0039] In particular, the hydrogen recirculation arrangement can measure the concentration of oxygen and / or nitrogen and compare it with the at least one contamination criterion. If the hydrogen analysis device determines that the contamination criterion is met, for example, the maximum permissible oxygen concentration value (e.g.

[0040] If the oxygen concentration (e.g., 1.5%, in particular 2% oxygen in the fluid stream) and / or the maximum permissible nitrogen concentration value (e.g., 2% nitrogen in the fluid stream) is exceeded, the hydrogen analysis device can control the at least one second fluid outlet such that it is opened, in particular so that the (contaminated) lost hydrogen can flow out. In other words, the lost hydrogen can be discharged. For example, a three-way valve can be provided as the second fluid outlet, which blocks flow to the first fluid outlet and allows the lost hydrogen to flow out.

[0041] The second fluid outlet can preferably be configured to forward the discharged (waste) hydrogen to at least one consumer entity, in particular a gas-fired power plant (of the hydrogen recirculation arrangement and / or the hydrogen production plant) or a pilot burner (of the hydrogen recirculation arrangement and / or the hydrogen production plant). The safety during operation of the hydrogen recirculation arrangement and / or the hydrogen production plant can be further improved.

[0042] Arranging the hydrogen analysis device downstream of the recirculation compressor is particularly advantageous compared to arranging it upstream of the recirculation compressor due to the increased pressure present there. In particular, a partial flow can be easily directed to the hydrogen analysis device.

[0043] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise at least one (further) hydrogen analysis device configured to analyze hydrogen (as already described). For example, the hydrogen recirculation arrangement can comprise two hydrogen analysis devices or just a single one.

[0044] According to a further embodiment, the at least one (further) hydrogen analysis device can be connectable to the third fluid connection. As already described, the hydrogen recirculation arrangement can comprise at least one second fluid outlet arranged in the fourth fluid connection (in particular comprising an outlet valve). As also described, the second fluid outlet can be controllable based on an analysis result of the (further) hydrogen analysis device. This hydrogen analysis device can operate or function analogously to the previously described hydrogen analysis device.

[0045] Arranging the hydrogen analysis device upstream of the recirculation compressor is advantageous compared to arranging it downstream of the recirculation compressor, particularly due to the longer time required for the lost hydrogen to flow to the second fluid outlet. In particular, the time available for performing the (previously described) analysis of the lost hydrogen by the hydrogen analysis device is increased. The safety of operating the hydrogen recirculation system and / or the hydrogen production plant can be further improved.

[0046] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise at least one (yet further) hydrogen analysis device configured to analyze hydrogen (as already described). For example, the hydrogen recirculation arrangement can comprise two or three hydrogen analysis devices, or just a single one.

[0047] The at least one (in particular yet another) hydrogen analysis device can be connectable to the first and / or second fluid connection (or a further fluid connection between the hydrogen loss point and the collection container). As already described, the hydrogen recirculation arrangement can comprise at least one second fluid outlet (in particular comprising an outlet valve) arranged in the fourth fluid connection (but also in the first or second fluid connection downstream of the hydrogen analysis device in the flow direction or in the third fluid connection). As also described, the second fluid outlet can be controllable based on an analysis result of the (further) hydrogen analysis device. This hydrogen analysis device can operate or function analogously to the previously described hydrogen analysis device.In particular, if it can be assumed that a hydrogen loss point has an increased risk of contamination compared to at least one other hydrogen loss point, this hydrogen loss point must be monitored (separately) by a hydrogen analysis device.

[0048] According to a further embodiment of the invention

[0049] In a hydrogen recirculation arrangement, the recirculation compressor can be a water-injected screw compressor, a piston compressor, a diaphragm compressor, or a combination thereof. Experience has shown that such compressors are particularly suitable for use as recirculation compressors in the hydrogen recirculation arrangement.

[0050] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the collection tank can have an operating pressure between -0.5 barg and 10 barg, preferably between 0 barg and 1 barg (particularly preferably substantially 0.5 barg). By setting a corresponding operating pressure of the collection tank, it can be easily ensured that the lost hydrogen flows from the at least two hydrogen loss points to or into the collection tank.

[0051] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the collection container can be a (simple) pressure vessel without internal components. Preferably, the collection container can be a collection container with an internal membrane (as in heating systems) or a gasometer. More preferably, the collection container can be a vertical container or a standing container, in particular with connection nozzles for the fluid connections from the hydrogen loss points on the lower container bottom.

[0052] According to a preferred embodiment of the hydrogen recirculation arrangement according to the invention, a fluid connection (e.g., in the form of separate nozzles) can be arranged on the collection container for at least the first and second (preferably for all) hydrogen loss points (as well as a corresponding respective fluid connection). This can reduce pressure and / or concentration fluctuations and any potential repercussions at the hydrogen loss points.

[0053] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the collecting container can comprise at least one pressure relief valve (e.g. a PCV and / or a PSV (pressure safety valve)) (in particular arranged in the ceiling area). The at least one pressure relief valve can be fluidically connected to a flare of the hydrogen recirculation arrangement. In particular, a spring-loaded relief valve against excess pressure can be arranged as the pressure relief valve. In particular, the pressure relief valve can be designed with a trigger pressure below the operating pressure at the hydrogen loss point with the lowest operating pressure. In particular, it has been recognized that the pressure at the at least two hydrogen loss points is thereby kept within a defined pressure range.

[0054] According to a further preferred embodiment of the hydrogen recirculation arrangement according to the invention, the at least one collecting container can be arranged adjacent to the hydrogen loss point of the at least two hydrogen loss points of the hydrogen production plant that has the lowest operating pressure among the at least two hydrogen loss points of the hydrogen production plant. In particular, it has been recognized that the pressure difference between a hydrogen loss point with a low (in particular lowest) operating pressure and the collecting container can be small. To nevertheless ensure reliable operation, the spatial distance, in particular the length of the at least one fluid connection between the hydrogen loss point and the collecting container, can be as small as possible.

[0055] In particular, it is therefore proposed to arrange the collection container as close as possible (preferably with a fluid connection length of less than 20 m, in particular less than 10 m, particularly preferably less than 5 m) to the hydrogen loss point of the at least two hydrogen loss points of the hydrogen production plant that has the lowest operating pressure among the at least two hydrogen loss points of the hydrogen production plant. According to a further preferred embodiment of the hydrogen recirculation arrangement according to the invention, the at least one collection container can be arranged in the compressor housing (in particular a compressor building) of the at least one main compressor of the hydrogen production plant.In particular, the collection container is thereby arranged in a secure manner and simultaneously adjacent to a hydrogen loss point of the hydrogen production plant (in particular the hydrogen loss point with the lowest operating pressure). Preferably, the at least one recirculation compressor can additionally be arranged in the compressor housing (in particular a compressor building) of the at least one main compressor of the hydrogen production plant.

[0056] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise at least one hydrogen processing device. The at least one hydrogen processing device can be configured to process (waste) hydrogen. In particular, the at least one hydrogen processing device can be configured to remove nitrogen from the fluid stream. According to a preferred variant, the activation of the hydrogen processing device can be based on the at least one (previously described) analysis result.

[0057] In particular, the hydrogen processing device in the hydrogen recirculation arrangement can be arranged downstream of the recirculation compressor in the flow direction.

[0058] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can further comprise a third fluid inlet connectable to a third hydrogen loss point of the hydrogen production plant. The third fluid inlet can be connected to the collection container at least via a fifth fluid connection of the recirculation hydrogen flow fluid network.

[0059] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise a fourth fluid inlet connectable to a fourth hydrogen loss point of the hydrogen production plant. The fourth fluid inlet can be connected to the collection container via at least one sixth fluid connection of the recirculation hydrogen flow fluid network.

[0060] According to a further embodiment of the hydrogen recirculation arrangement according to the invention, the hydrogen recirculation arrangement can comprise at least a fifth fluid inlet connected to a first hydrogen loss point of the hydrogen recirculation arrangement (e.g., the recirculation compressor and / or an optional hydrogen analysis device of the hydrogen recirculation arrangement). The fifth fluid inlet can be connected to the collection container via at least one seventh fluid connection of the recirculation hydrogen flow fluid network. By additionally capturing and recirculating the (unavoidable) hydrogen losses in the hydrogen recirculation arrangement, the operating efficiency of the hydrogen production plant can be further improved. It is understood that, in variants of the invention, additional fluid inlets can be provided for additional hydrogen loss points of the hydrogen recirculation arrangement or the hydrogen production plant.

[0061] As already described, another aspect of the invention is a hydrogen production plant.

[0062] According to one embodiment of the hydrogen production plant according to the invention, the hydrogen production plant can comprise at least one further production device. In particular, the at least one further production device can be a main processing device. The main processing device can be configured to process the hydrogen generated by the electrolyzer. The main processing device can preferably be arranged between the electrolyzer and the main compressor and, in particular, can be fluidically connected to the electrolyzer and the main compressor.

[0063] The at least one hydrogen processing module of the main processing device can, in particular, be a drying module (or a drying device). The drying module can be configured to dry the (wet) hydrogen obtained from the electrolyzer. Wet hydrogen is understood here to mean, in particular, hydrogen saturated with water or a two-phase mixture of water-saturated hydrogen and liquid water. Dry hydrogen is understood here to mean, in particular, hydrogen that is not saturated with water, i.e., whose dew point is (significantly) below the actual temperature at the prevailing pressure. In other words, an electrolyzer produces, in particular, moist hydrogen gas, which, upon cooling, becomes a gas-liquid mixture in the form of a water-hydrogen mixture.In other words, a two-phase stream of hydrogen and water flows through the main hydrogen flow fluid network, specifically as so-called "wet" hydrogen. The gas, or gaseous phase, carries the liquid phase with it.

[0064] Preferably, an adsorption drying module (in particular a TSA (temperature swing adsorption) system) and / or a cold drying module can be provided as the drying device (after separation of the liquid phase). The adsorption drying module is in particular configured to dry the wet hydrogen by adsorption using a (suitable) absorber, in particular silica spheres. The respective drying module can be configured to cool the wet hydrogen to a temperature of at least less than 5°C. It is understood that in variants of the application, other hydrogen drying devices can be used alternatively or additionally.

[0065] Furthermore, the main processing device can optionally comprise a catalytic deoxification stage or a plurality of corresponding modules, in particular for treating the wet hydrogen prior to the drying process described above. Such a stage serves to remove oxygen (<0.5%). In variants of the invention, such treatment can also be carried out at a later time.

[0066] As already described, the hydrogen production plant may comprise a main hydrogen flow fluid network.

[0067] According to a further embodiment of the hydrogen production plant according to the invention, the hydrogen production plant can comprise at least one water treatment device, preferably with a plurality of first water treatment modules. A water treatment module can be configured to treat the water such that the treated water can be used in the electrolyzer for hydrogen production.

[0068] For example, especially in an offshore hydrogen production plant, the water treatment plant can prepare seawater for electrolysis.

[0069] Preferably, a water treatment device can be a seawater desalination device with membrane-based pressure filtration. Such a seawater desalination device can, in particular, perform reverse osmosis, ultrafiltration, and / or electrodialysis (also called electrodeionization (EDI)) to treat the water, or treat the seawater accordingly. Such a treatment can be used, particularly in an energy-efficient manner, to treat seawater that can be used for water electrolysis in an electrolysis device. The treated water can also be referred to as ultrapure water or "demine water." It is understood that in other variants of the invention, other water treatment devices can also be used alternatively or additionally, such as a seawater desalination device with thermal (vacuum) distillation.

[0070] According to a preferred embodiment of the hydrogen production plant, the first hydrogen loss point can be the main compressor. In particular, it has been recognized that the following hydrogen loss points can exist in a hydrogen production plant:

[0071] 1. Main compressor of the hydrogen production plant: Cracked gas losses to at least one main compressor, particularly in the form of a piston compressor. So-called dry gas seals are generally used in a main compressor. The reason for this is in particular that oil-lubricated pistons of a main compressor would contaminate the produced hydrogen with oil. Several seal packings on the piston rods can reduce hydrogen losses from the interior towards the center at, for example, 30-70 bar. Nitrogen can be added from the outside as a barrier gas, but this must be removed separately with a hydrogen content. In particular, it has been found that hydrogen losses in the form of cracked gas losses in the center amount to between 1% and 2% of the production quantity per compressor stage and increase particularly as the seal packings age.

[0072] 2. Hydrogen analysis device of the hydrogen production plant: Hydrogen losses occur at the at least one hydrogen analysis device after the measurement. At least one such hydrogen analysis device can be provided per electrolysis module of the electrolyzer. The hydrogen analysis device can include a bypass around the actual measuring device. The larger the current through this bypass, the smaller the time delay of the measured value compared to the actual value within the electrolysis module or the process device. Increasing the bypass current in conjunction with its recirculation thus enables a reduction in the measurement delay without additional product loss.

[0073] 3. Low-pressure separators of the hydrogen production plant: Hydrogen losses also occur at low-pressure separators. In a low-pressure separator, the liquid phase from the high-pressure separator is depressurized to a lower pressure to remove further hydrogen from the water phase. This is particularly necessary because some of this water can later reach the oxygen side. For safety reasons, no dissolved hydrogen should be present here. On the oxygen side, in particular, the maximum hydrogen content in the oxygen is 2%, as this is half the lower explosion limit.

[0074] Low-pressure separators typically operate at an operating pressure between 3 barg and 8 barg.

[0075] 4. Drying device of the hydrogen production plant: Furthermore, hydrogen regeneration gas losses can occur during drying by adsorption. Regeneration of the adsorber bed occurs particularly at higher temperatures (so-called TSA) and / or lower pressures (so-called PSA). This also leads to hydrogen losses.

[0076] At least two of the hydrogen loss points mentioned, preferably at least three, particularly preferably all hydrogen loss points of the hydrogen production plant can be fluidically coupled to the hydrogen return arrangement in the manner described above.

[0077] According to a preferred embodiment of the invention

[0078] In a hydrogen production plant, the electrolyzer may have an operating pressure between 3 barg and 70 barg (preferably between 25 barg and 40 barg, more preferably substantially 32 barg).

[0079] Alternatively or additionally, the main compressor may be configured to compress the hydrogen generated by the electrolyzer to an operating pressure between 60 barg and 250 bar, preferably between 70 barg and 200 barg.

[0080] Furthermore, at least one controller can be provided, configured to control the components of the hydrogen production plant and / or the

[0081] Hydrogen recirculation arrangement.

[0082] Yet another aspect of the invention is a hydrogen recycling process for a hydrogen production plant (particularly as described above). The hydrogen production plant comprises at least one main compressor fluidly connected to at least one electrolyzer via a main hydrogen flow fluid network. The hydrogen recycling process comprises:

[0083] Passing at a first hydrogen loss point of the

[0084] hydrogen production plant via a first fluid connection to a collecting tank of the hydrogen recirculation arrangement,

[0085] Passing at a second hydrogen loss point of the

[0086] hydrogen production plant via a second fluid connection to the collection tank,

[0087] Passing the hydrogen collected in the collection container via a third fluid connection to a recirculation compressor, and

[0088] Conveying the hydrogen compressed by the recirculation compressor via a fourth fluid connection to the main hydrogen flow fluid network of the hydrogen production plant. The method is used in particular for operating a previously described hydrogen recirculation arrangement, in particular in a previously described hydrogen production plant.

[0089] A previously described module, arrangement, device, etc. may comprise at least some hardware elements (e.g., processor, memory means, etc.) and / or at least some software elements (e.g., executable code). It should also be noted that terms such as "first," "second," "further," etc., do not indicate a sequence, but rather serve to distinguish between two elements (e.g., fluid inlet, fluid outlet, etc.).

[0090] The features of the hydrogen recycling system, the hydrogen production plants, and the hydrogen recycling processes can be freely combined with one another. In particular, features of the description and / or the dependent claims can be independently inventive, even if they completely or partially circumvent features of the independent claims, either alone or in freely combined form.

[0091] There are now numerous possibilities for designing and further developing the hydrogen recycling arrangement, the hydrogen production plant, and the hydrogen recycling process according to the invention. Reference is made, on the one hand, to the claims subordinate to the independent patent claims and, on the other hand, to the description of exemplary embodiments in conjunction with the drawing. The drawing shows:

[0092] Fig. 1 is a schematic view of an embodiment of a hydrogen recirculation arrangement according to the present invention, Fig. 2 is a schematic view of an embodiment of a hydrogen production plant according to the present invention with an embodiment of a hydrogen recirculation arrangement according to the present invention,

[0093] Fig. 3 is a diagram of an embodiment of a hydrogen recycling process according to the present invention, and

[0094] Fig. 4 shows an embodiment of a compressor housing of a main compressor of an embodiment of a hydrogen production plant according to the present invention.

[0095] In the following, similar reference numerals are used for similar elements.

[0096] Figure 1 shows a schematic view of an embodiment of a hydrogen recirculation arrangement 100 according to the present invention for a hydrogen production plant (not shown). The hydrogen production plant comprises at least one main compressor fluidly connected to at least one electrolyzer of the hydrogen production plant via a main hydrogen flow fluid network.

[0097] The hydrogen recirculation arrangement 100 comprises a first fluid inlet 102 connectable to a first hydrogen loss point of the hydrogen production plant. The first fluid inlet 102 is connected to at least one collecting container 106 of the hydrogen recirculation arrangement 100 via at least one first fluid connection 110 (for example in the form of a fluid pipe or a fluid line) of a recirculation hydrogen flow fluid network 120.

[0098] In particular, the hydrogen recirculation arrangement 100 can comprise the recirculation hydrogen stream fluid network 120. Furthermore, the hydrogen recirculation arrangement 100 comprises a second fluid inlet 104 connectable to a second hydrogen loss point of the hydrogen production plant. The second fluid inlet 104 is connected to the collection container 106 via at least one second fluid connection 112 (for example, in the form of a fluid pipe or a fluid line) of the recirculation hydrogen stream fluid network 120.

[0099] It is understood that in variants of the invention, three or more fluid inlets may also be present. A respective fluid inlet 102, 104 is configured, in particular, for fluidically coupling the respective hydrogen loss point to the recirculation hydrogen flow fluid network 120, in particular such that the lost hydrogen exiting the hydrogen production plant at the respective hydrogen loss point and, in particular, captured by the hydrogen loss point, is or can flow through the respective fluid inlet 102, 104 into the recirculation hydrogen flow fluid network 120 and, in particular, to the collection container 106.

[0100] The collection tank 106 can be a (simple) pressure vessel without any internal components. Preferably, the collection tank 106 can be a collection tank 106 with an internal membrane (as in heating systems) or a gasometer. Preferably, the collection tank 106 can be a vertical container.

[0101] The operating pressure of the collection tank 106 is selected, in particular, such that it is at least lower than the respective operating pressure of the at least two hydrogen loss points. In particular, the collection tank 106 can have an operating pressure between -0.5 barg and 10 barg, preferably between 0 barg and 1 barg.

[0102] As can also be seen from Figure 1, the

[0103] Hydrogen recirculation arrangement 100 at least one recirculation compressor 108 connected to the collection container 106 via at least one third fluid connection 114 (for example in the form of a fluid pipe or a fluid line) of the recirculation hydrogen flow fluid network 120. The at least one recirculation compressor 108 is in particular a water-injected screw compressor or a piston compressor or a diaphragm compressor or a combination thereof.

[0104] The hydrogen recirculation arrangement 100 comprises at least one first fluid outlet 118 connectable to a main hydrogen flow fluid network of the hydrogen production plant. The first fluid outlet 118 is connected to the recirculation compressor 108 via at least one fourth fluid connection 116 (for example in the form of a fluid pipe or a fluid line) of the recirculation hydrogen flow fluid network 120.

[0105] Figure 2 shows a schematic view of an embodiment of a hydrogen production plant 222 according to the present invention with an embodiment of a hydrogen recirculation arrangement 200 according to the present invention. To avoid repetition, only the differences from the embodiment according to Figure 1 are described below, and otherwise reference is made to the explanations for Figure 1.

[0106] The hydrogen production plant 222 comprises at least one main compressor 226 fluidly connected to at least one electrolyzer 224 of the hydrogen production plant 222. In particular, the hydrogen production plant 222 comprises a main hydrogen flow fluid network 232 with preferably a plurality of (main) fluid connections 234, 236, 238 (e.g., each in the form of a fluid pipe or a fluid line).

[0107] The electrolyzer 224 may, in particular, comprise an electrolyzer stack, for example, a proton exchange membrane (PEM) electrolyzer. The electrolyzer 224 may have an operating pressure between 3 barg and 70 barg. In particular, treated water may be supplied to the electrolyzer 224 via a further fluid line 266, in particular from a water treatment device (not shown) of the hydrogen production plant 222.

[0108] The main compressor 226 can be configured to compress the hydrogen generated (and in particular processed) by the electrolyzer 224, in particular the dried hydrogen, preferably to an operating pressure between 60 barg and 250 barg, preferably between 70 barg and 200 barg. A compressor of the main compressor 226 can comprise at least one hydrogen compressor (in particular a piston compressor).

[0109] Preferably, the hydrogen production plant 222 may comprise at least one further production device, in this case, for example, a main processing device 228. The optional main processing device 228 may be configured to process the hydrogen generated by the electrolyzer 224. As illustrated, the main processing device 228 may preferably be arranged between the electrolyzer 224 (connected via at least one fluid connection 234) and the main compressor 226 (connected via at least one fluid connection 234).

[0110] The at least one hydrogen processing module of the main processing device 228 can, in particular, be a drying module (or a drying device). The drying module can be configured to dry the (wet) hydrogen produced by the electrolyzer 224. Preferably, a TSA system and / or a cold drying module can be provided as the drying device. The adsorption drying module is, in particular, configured to dry the wet hydrogen by adsorption using a (suitable) absorber, in particular silica spheres.

[0111] Furthermore, the main treatment device 228 may optionally comprise a catalytic

[0112] A deoxo stage or a plurality of corresponding modules, particularly for treating the wet hydrogen prior to the drying process described above, is included. Such a stage serves to remove oxygen (<0.5%).

[0113] In addition, the hydrogen production plant 222 may comprise a fluid outlet 230 (connected to the main compressor 226 via at least one fluid connection 238), in particular to deliver the produced hydrogen to a hydrogen consumer, for example an external hydrogen network or pipeline network.

[0114] The hydrogen production plant 222 comprises at least a first hydrogen loss point 240 and a second hydrogen loss point 242. By way of example, the hydrogen production plant 222 here comprises a third hydrogen loss point 244.

[0115] Exemplary and non-limiting hydrogen loss points are the main compressor 226, a hydrogen analysis device (not shown) of the hydrogen production plant 222, a low-pressure separator (not shown) of the hydrogen production plant 222, and a drying device of the hydrogen production plant 222. In variants of the invention, the hydrogen recirculation assembly 200 may include at least one fifth fluid inlet (not shown) connected to a first (not shown) hydrogen loss point of the hydrogen recirculation assembly (e.g., the recirculation compressor and / or an optional hydrogen analysis device) and connected to the collection container 206 via a fluid connection (not shown).

[0116] As previously described, the hydrogen production system 222 includes a hydrogen recirculation assembly 200. The first fluid inlet 202 of the hydrogen recirculation assembly 200 is connected to the first hydrogen loss point 240, and the second fluid inlet 204 of the hydrogen recirculation assembly 200 is connected to the second hydrogen loss point 242. Furthermore, a third fluid inlet 268 of the hydrogen recirculation assembly 200 is shown connected to the third hydrogen loss point 244.

[0117] As can be seen, the collecting container 206 is connected to the first fluid inlet 202 via a first fluid connection 210, to the second fluid inlet 204 via a second fluid connection 212 and, for example, to the third fluid inlet 268 via a fifth fluid connection 246. For example, the first fluid connection 210 and the second fluid connection 212 are directly connected to a respective connection of the collecting container 206, while the fifth fluid connection 246 is indirectly connected to the collecting container 206 via the second fluid connection 212.

[0118] Furthermore, in this case, the first, second, and fifth fluid connections 246 each have a backflow prevention module 248, 250, 252. For example, the first backflow prevention module 248 is a pressure-maintaining valve, the second backflow prevention module 250 is a check valve, and the third backflow prevention module 252 is a shut-off valve. It is understood that in other variants of the invention, a different valve configuration may be provided, for example, three identical backflow prevention modules.

[0119] Furthermore, Figure 2 shows that the collection vessel 206 includes at least one pressure relief valve 262 (e.g., a PCV and / or a PSV). The pressure relief valve 262 may be connected to a flare of the hydrogen recirculation assembly 200.

[0120] As already described, the collection tank 206 is connected to the recirculation compressor 208 via a third fluid connection 214. Furthermore, the recirculation compressor 208 is connected to a first fluid outlet 218 (e.g., a 3-way valve) via at least one fourth fluid connection 216.1, 216.2 (here, for example, two fourth fluid connections 216.1, 216.2) and via an optional hydrogen processing device 264. The first fluid outlet 218 is fluidly connected, in particular, to the main hydrogen stream fluid network 232. Preferably, the first fluid outlet 218 can be connected to the fluid connection 234 of the main hydrogen stream fluid network 232, which is directly connected to the electrolyzer 224, as shown in Figure 2.

[0121] The (optional) hydrogen processing device 264 is particularly configured to remove nitrogen from the waste hydrogen stream.

[0122] In addition, the hydrogen recirculation arrangement 200 comprises, in the present case, three hydrogen analysis devices 254, 256, 258, by way of example. In variants of the invention, only two hydrogen analysis devices (for example 256 and 258) or only one hydrogen analysis device, such as in particular the hydrogen analysis device 256, can be provided.

[0123] As can further be seen from Figure 2, for example, a first hydrogen analysis device 254 is connected to the third fluid connection 214, a second hydrogen analysis device 256 is connected to one of the fourth fluid connections 216.2, and the third hydrogen analysis device 258 is connected to the second fluid connection 212, in particular downstream of the connection point between the second fluid connection 212 and the fifth fluid connection 246.

[0124] The at least one hydrogen analysis device 254, 256, 258 can be configured to analyze lost hydrogen or the lost fluid stream. In particular, a partial stream of the lost hydrogen from the recirculation hydrogen stream fluid network 220 can be directed to the respective hydrogen analysis device 254, 256, 258.

[0125] The at least one hydrogen analysis device 254, 256, 258 is particularly configured to determine the composition of the lost hydrogen or the corresponding fluid stream. In particular, the at least one hydrogen analysis device 254, 256, 258 can be configured to (approximately) determine the nitrogen concentration in the lost hydrogen. Preferably, the at least one hydrogen analysis device 254, 256, 258 can additionally be configured to (approximately) determine the oxygen concentration in the lost hydrogen.

[0126] For example, the hydrogen analysis device 254, 256, 258 may include at least one thermal conductivity analyzer. The thermal conductivity analyzer may, in particular, be configured to measure the nitrogen and oxygen in the lost hydrogen. Alternatively or additionally, the hydrogen analysis device 254, 256, 258 may include at least one fuel cell sensor. The fuel cell sensor may be configured to measure the oxygen concentration in the lost hydrogen.

[0127] Preferably, the hydrogen recirculation arrangement can comprise at least one second fluid outlet 260 (in particular comprising an outlet valve, such as a 3-way valve or two shut-off valves) arranged in one of the fourth fluid connections 216.2 downstream of the fluid connection point of the second hydrogen analysis device 256. The second fluid outlet 260 can be controlled, at least based on an analysis result of the at least one hydrogen analysis device 254, 256, 258.

[0128] In particular, at least one contamination criterion can be specified, which can be stored, for example, in a data memory of the hydrogen analysis device 254, 256, 258. The contamination criterion can, in particular, be selected such that fulfillment of the contamination criterion (e.g. at least one concentration limit value, such as a maximum permissible oxygen concentration value and / or a maximum permissible nitrogen concentration value) indicates that the lost hydrogen is contaminated with other substances (in particular oxygen and / or nitrogen) to such an extent that feedback into the main hydrogen stream fluid network 232 should be prevented. In particular, fulfillment of the contamination criterion can be determined by comparing the measured concentration value, such as the nitrogen concentration value and / or oxygen concentration value, and the maximum permissible oxygen concentration value orthe maximum permissible nitrogen concentration value. The contamination criterion can depend on the mass ratio of the recirculated stream to the main stream, as well as the contamination of the main stream from the electrolyzer 224 and the resulting mathematically expected mixed contamination at the fluid outlet 230.

[0129] If the at least one hydrogen analysis device 254, 256, 258 determines that the contamination criterion is met, for example, the maximum permissible oxygen concentration value (e.g., 1.5%, in particular 2% oxygen in the fluid stream) and / or the maximum permissible nitrogen concentration value (e.g., 2% nitrogen in the fluid stream) is exceeded, the hydrogen analysis device 254, 256, 258 can control the at least one second fluid outlet 260 such that it is opened so that the (contaminated) hydrogen can flow out (completely). In particular, a flow to the first fluid outlet 218 can be blocked by the second fluid outlet 260 at the same time.

[0130] In other words, all of the lost hydrogen can be removed. In particular, the hydrogen recirculation system 200 and, if applicable, the hydrogen production system 222 can then be cleaned in a known manner.

[0131] The second fluid outlet 260 can preferably be configured to forward the discharged (waste) hydrogen to at least one consumer entity (not shown), in particular a gas-fired power plant (of the hydrogen recirculation arrangement 200 and / or the hydrogen production plant 222) or a pilot burner (of the hydrogen recirculation arrangement 200 and / or the hydrogen production plant 222). Figure 3 shows a diagram of an embodiment of a hydrogen recirculation method according to the present invention. The method serves in particular for operating a previously described hydrogen recirculation arrangement 100, 200 (see, for example, Fig. 1 and / or 2), in particular in a previously described hydrogen production plant 222 (see, for example, Fig. 2).

[0132] In a step 301, hydrogen exiting at a first hydrogen loss point of the hydrogen production plant or a lost hydrogen stream is conducted via a first fluid connection to a collecting container of the hydrogen recirculation arrangement, as described.

[0133] In step 303, hydrogen exiting at a second hydrogen loss point of the hydrogen production plant or a lost hydrogen stream is passed via a second fluid connection to the collection container, as described.

[0134] In a step 305, the hydrogen collected in the collection container is passed via a third fluid connection to a recirculation compressor, as described.

[0135] In a step 307, the hydrogen compressed by the recirculation compressor is passed via a fourth fluid connection to the main hydrogen stream fluid network of the hydrogen production plant, as already described.

[0136] Steps 301, 303, 305 and 307 may be performed at least partially simultaneously.

[0137] Figure 4 shows an embodiment of a compressor housing 470 of a

[0138] Main compressor 426 of an embodiment of a hydrogen production plant according to the present invention. In particular, the embodiment of Figure 4 can be combined with the embodiment of Figure 2.

[0139] According to the illustrated preferred embodiment of a hydrogen production plant, the at least one collection container 406 can be arranged adjacent to the hydrogen loss point (here, for example, the main compressor 426) of the at least two hydrogen loss points of the hydrogen production plant that has the lowest operating pressure among the at least two hydrogen loss points of the hydrogen production plant. In particular, the collection container is arranged as adjacent as possible (preferably with a fluid connection length of less than 20 m, in particular less than 10 m, particularly preferably less than 5 m) to the hydrogen loss point of the at least two hydrogen loss points of the hydrogen production plant that has the lowest operating pressure among the at least two hydrogen loss points of the hydrogen production plant.

[0140] In particular, the at least one collection container 406 can be arranged in the compressor housing 470 (in particular a compressor building) of the at least one main compressor 426 of the hydrogen production plant. Preferably, the at least one recirculation compressor 408 can additionally be arranged in the compressor housing 470 (in particular a compressor building) of the at least one main compressor 426 of the hydrogen production plant.

[0141] In a further variant of the invention, non-continuous streams can also be recycled via the hydrogen recirculation system (also referred to as a recycling system). This can be hydrogen that still contains too much nitrogen upon startup after an off- or cold standby, for example, containing 20% ​​nitrogen. Particularly preferably, the hydrogen accumulating during depressurization during a shutdown process (in off- or low-pressure standby) is recycled, as this is not contaminated and the depressurization process can be delayed if necessary, depending on the available free capacity of the hydrogen recirculation system.

[0142]

[0143] 100 hydrogen recirculation arrangement

[0144] 102 first fluid inlet

[0145] 104 second fluid inlet

[0146] 106 collection containers

[0147] 108 Recirculation compressor

[0148] 110 first fluid connection

[0149] 112 second fluid connection

[0150] 114 third fluid connection

[0151] 116 fourth fluid connection

[0152] 118 first fluid outlet

[0153] 120 recycle hydrogen stream fluid network

[0154] 200 hydrogen recirculation arrangement

[0155] 202 first fluid inlet

[0156] 204 second fluid inlet

[0157] 206 collection containers

[0158] 208 Recirculation compressor

[0159] 210 first fluid connection

[0160] 212 second fluid connection

[0161] 214 third fluid connection

[0162] 216 fourth fluid connection

[0163] 218 first fluid outlet

[0164] 220 Recycle hydrogen stream fluid network

[0165] 222 Hydrogen production plant

[0166] 224 Electrolyzer

[0167] 226 Main compressor

[0168] 228 Main treatment device

[0169] 230 Fluid outlet of the hydrogen production plant

[0170] 232 Main hydrogen flow fluid network 234 Fluid connection

[0171] 238 Fluid connection

[0172] 240 first hydrogen loss point

[0173] 242 second hydrogen loss point

[0174] 244 third hydrogen loss point

[0175] 246 fifth fluid connection

[0176] 248 first backflow prevention module

[0177] 250 second backflow prevention module

[0178] 252 third backflow prevention module

[0179] 254 Hydrogen analysis device

[0180] 256 Hydrogen analysis device

[0181] 258 Hydrogen analysis device

[0182] 260 second fluid outlet

[0183] 262 pressure relief valve

[0184] 264 Hydrogen processing device

[0185] 266 Fluid line

[0186] 268 third fluid inlet

[0187] 301 step

[0188] 303 steps

[0189] 305 steps

[0190] 307 steps

[0191] 406 collection containers

[0192] 408 Recirculation compressor

[0193] 426 Main compressor

[0194] 470 compressor housing

Claims

Patent claims 1. Hydrogen recirculation arrangement (100, 200) for a Hydrogen production plant (222), wherein the hydrogen production plant (222) comprises at least one main compressor (226, 426) fluidically connected to at least one electrolyzer (224, 424) via a main hydrogen flow fluid network (232), characterized in that the hydrogen recirculation arrangement (100, 200) comprises: a first fluid inlet (102, 202) connectable to a first hydrogen loss point (240) of the hydrogen production plant (222), which is connected via at least one first fluid connection (110, 210) to at least one collecting container (106, 206) of the hydrogen recirculation arrangement (100, 200), a second fluid inlet (104, 204) connectable to a second hydrogen loss point (242) of the hydrogen production plant (222), which is connected via at least one second fluid connection (112, 212) to the collecting container (106, 206), at least one via at least one third fluid connection (114) with the collecting container (106,206) connected to a recirculation compressor (108, 208), and at least one first fluid outlet (118, 218) connectable to a main hydrogen stream fluid network (232) of the hydrogen production plant (222), which is connected to the recirculation compressor (108, 208) via at least one fourth fluid connection (116).

2. Hydrogen recirculation arrangement (100, 200) according to claim 1, characterized in that the first fluid inlet (102, 202) and / or the first fluid connection (110, 210) comprises at least one backflow prevention module (248), and / or the second fluid inlet (104, 204) and / or the second fluid connection (112, 212) comprises at least one backflow prevention module (250), and / or the first fluid outlet (118, 218) and / or the fourth fluid connection (116, 216) comprises at least one backflow prevention module (252).

3. Hydrogen recirculation arrangement (100, 200) according to claim 1 or 2, characterized in that the hydrogen recirculation arrangement (100, 200) further comprises: at least one hydrogen analysis device (254, 256, 258) configured to analyze hydrogen, wherein the at least one hydrogen analysis device (254, 256, 258) is connectable to the fourth fluid connection (116, 216) at a fluid connection point, and at least one second fluid outlet (260) arranged in the fourth fluid connection (116, 216) downstream of the fluid connection point of the hydrogen analysis device (254, 256, 258), wherein the second fluid outlet (260) is controllable, at least based on an analysis result of the hydrogen analysis device (254, 256, 258).

4. Hydrogen recirculation arrangement (100, 200) according to one of the previous Claims, characterized in that the Hydrogen recirculation arrangement (100, 200) further comprises: at least one hydrogen analysis device (254, 256, 258) configured to analyze hydrogen, wherein the at least one hydrogen analysis device (254, 256, 258) is connectable to the third fluid connection (114, 214), and at least one second fluid outlet (260) arranged in the fourth fluid connection (116, 216), wherein the second fluid outlet (260) is controllable based on an analysis result of the hydrogen analysis device (254, 256, 258).

5. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the recirculation compressor (108, 208) is a water-injected screw compressor, or a piston compressor or a diaphragm compressor or a combination thereof.

6. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the collecting container (106, 206) has an operating pressure between -0.5 barg and 10 barg, preferably between 0 barg and 1 barg.

7. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the collecting container (106, 206) comprises at least one pressure relief valve (262).

8. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the at least one collecting container (106, 206) is arranged adjacent to the hydrogen loss point (240, 242, 244) of the at least two hydrogen loss points (240, 242, 244) of the hydrogen production plant (222) which has the lowest operating pressure among the at least two hydrogen loss points (240, 242, 244) of the hydrogen production plant (222).

9. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the at least one collecting container (106, 206) is arranged in the compressor housing (470) of the at least one main compressor (226, 426) of the hydrogen production plant (222).

10. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the hydrogen recirculation arrangement (100, 200) further comprises: at least one hydrogen processing device (228) configured to process hydrogen, wherein in particular the hydrogen processing device (228) is arranged in the hydrogen recirculation arrangement (100, 200) downstream of the recirculation compressor (108, 208) in the flow direction.

11. Hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, characterized in that the hydrogen recirculation arrangement (100, 200) further comprises: a third fluid inlet (268) connectable to a third hydrogen loss point (244) of the hydrogen production plant (222), which is connected to the collecting container (106, 206) via a fifth fluid connection (246).

12. Hydrogen production plant (222), comprising: at least one main compressor (226, 426) fluidically connected to at least one electrolyzer (224, 424) of the hydrogen production plant (222), at least one first hydrogen loss point (240) and one second hydrogen loss point (242), characterized in that the hydrogen production plant (222) further comprises a hydrogen recirculation arrangement (100, 200) according to one of the preceding claims, wherein the first fluid inlet (102, 202) of the hydrogen recirculation arrangement (100, 200) is connected to the first hydrogen loss point (240) and the second fluid inlet (104, 204) of the hydrogen recirculation arrangement (100, 200) is connected to the second hydrogen loss point (242).

13. Hydrogen production plant (222) according to claim 12, characterized in that the first hydrogen loss point (240) is the main compressor (226, 426).

14. Hydrogen production plant (222) according to claim 12 or 13, characterized in that the electrolyzer (224, 424) has an operating pressure between 3 barg and 70 barg, and / or the main compressor (226, 426) is designed to compress hydrogen to an operating pressure between 60 barg and 250 barg, preferably between 70 barg and 200 barg.

15. A hydrogen recirculation method for a hydrogen production plant (222), the hydrogen production plant (222) comprising at least one main compressor (226, 426) fluidly connected to at least one electrolyzer (224, 424) via a main hydrogen flow fluid network (232), the method comprising: Conducting hydrogen escaping from a first hydrogen loss point (240) of the hydrogen production plant (222) via a first fluid connection (110, 210) to a collecting container (106, 206) of the hydrogen recirculation arrangement (100, 200), conducting hydrogen escaping from a second hydrogen loss point (242) of the hydrogen production plant (222) via a second fluid connection (112, 212) to the collection container (106, 206), Directing the hydrogen collected in the collection container (106, 206) via a third fluid connection (114, 214) to a recirculation compressor (108, 208), and Passing the hydrogen compressed by the recirculation compressor (108, 208) via a fourth fluid connection (116, 216) to the Main hydrogen flow fluid network (232) of the hydrogen production plant (222).

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