Modular electrolysis system

Abstract

The present invention relates to a modular electrolysis system comprising a plurality of modules wherein each module of the plurality of modules comprises a support frame and at least one interface accessible from outside the support frame and configured to connect the module with at least one of the remaining modules, the plurality of modules includes: a water-gas crude separation module located downstream of the anode outlet of the electrolytic cell module; and a water-gas fine separation module located downstream of the liquid outlet of the water-gas coarse separation module.

Description

[0001] This invention relates to a modular electrolysis system. Background Technology

[0002] Typically, electrolysis equipment for producing hydrogen and optionally oxygen from water is designed to meet specific customer needs and is adapted to local requirements such as climate conditions and on-site energy availability. Therefore, a typical large-scale electrolysis system is a custom-made unit. Electrolysis is preferably carried out in a PEM electrolytic cell.

[0003] One of the major safety challenges associated with water electrolysis is the explosion hazard caused by hydrogen leaking into the oxygen products. Hydrogen is a very small molecule with a very high diffusion coefficient, and is therefore very difficult to contain within the confined space of such electrolysis equipment. Hydrogen can form an explosive mixture with the oxygen produced by the electrolysis system, which, in some cases, can ignite and damage the electrolysis system due to the resulting explosion.

[0004] Some exemplary reasons for the formation of such explosive mixtures of hydrogen and oxygen in electrolysis systems should be noted here: the pressure difference between the electrodes can cause a constant transfer of hydrogen across the membrane (so-called "cross-permeation"). Therefore, in certain operating scenarios (e.g., partial loading, startup, shutdown, or quiescence of a standalone electrolyzer or a so-called stack), hydrogen may accumulate on the oxygen side of the electrolysis unit during operation. Hydrogen may also leak from the cathode side to the anode side through membrane perforations, for example, at bar exceeding 20 or 30 bar, due to undetected membrane defects during electrolyzer operation. Membrane rupture can cause a sudden transfer of large amounts of hydrogen from the cathode side to the anode side.

[0005] As a remedy for such situations, EP 3 971 324 A1 discloses, for example, an electrolysis apparatus in which an inert gas is incorporated into the oxygen product stream to reduce the hydrogen concentration.

[0006] However, because measures are only taken when a certain hydrogen concentration is detected, the measures described in EP 3 971 324 A1 cannot guarantee inherently safe operation. Furthermore, analytical equipment often has excessively long response times that prevent safe operation from being ensured. Summary of the Invention

[0007] In the context outlined above, the task is to reduce the risk of explosions in water electrolysis (e.g., PEM (proton exchange membrane) electrolysis) and thus improve the operation of the electrolysis system. In this regard, within the context of this invention, internal leakage means the cross-permeation of hydrogen from the high-pressure system (hydrogen system; cathode side of the electrolysis) to the low-pressure system (oxygen / water system; anode side of the electrolysis). In the context of this invention, the operating pressure of the hydrogen system can be approximately 30 bar, and the oxygen / water side can operate under low-pressure conditions (e.g., in the range of atmospheric pressure up to 3 or 5 bar). A potential point of cross-permeation is the electrolysis reactor. At the electrolysis reactor, a membrane separates the hydrogen from the oxygen / water system.

[0008] Another objective of this invention is to reduce the development, investment, and maintenance costs associated with large-scale electrolysis systems.

[0009] The present invention addresses these objectives in at least part by providing a modular electrolysis system and corresponding modules according to the appended independent claims. Advantageous embodiments and additional aspects are the subject matter of the corresponding dependent claims and the following description.

[0010] The modular electrolysis system according to the invention comprises a plurality of modules, each of which includes a support frame and at least one interface accessible from outside the support frame and configured to connect the respective module to at least one of the remaining modules. The frame and interface allow each module to be prefabricated individually in a workshop remote from the installation site and transported separately from the workshop to the installation site. "Remote" means more than 10 km, more than 100 km, or even thousands of kilometers.

[0011] The multiple modules include two modules for water-gas separation: a coarse water-gas separation module located downstream of the anode outlet of the electrolytic cell module; and a fine water-gas separation module located downstream of the liquid outlet of the coarse water-gas separation module. In embodiments, the multiple modules also include at least one of the following: a power supply module, a water supply module, and an electrolytic cell module comprising at least one electrolytic cell stack. The term "multiple" means "at least two," "at least three," "at least five," or even "at least ten." Preferably, the system includes more than ten modules, for example, 12 to 24, more preferably 13 to 17; even higher numbers, for example, 100 to 700, are possible. If the system includes a single electrolytic cell module, the system may have four to ten (preferably five to seven) modules. If the system includes more than one electrolytic cell module, the total number of modules is correspondingly higher, for example, about 120 for a 200MW system. If the system becomes even larger, for example, 500MW or 1000MW, then the number is approximately proportionally higher. The system may contain one, multiple, or several modules of each type, for example, multiple electrolyzer modules or multiple water-gas coarse separation modules.

[0012] A coarse water-gas separation module is configured to process a water-containing mixture drawn from an electrolysis module via an interface between two modules. This coarse water-gas separation module then delivers a gas-lean mixture to a fine water-gas separation module, which is configured to further separate gas from the gas-lean mixture and deliver an additional gas-lean fluid, preferably pure water free of gas. The gas-lean mixture is conveyed through the interfaces of both the coarse and fine water-gas separation modules.

[0013] In the electrolytic cell module, refined, cooled, and filtered demineralized water is pumped to five electrolytic stack assemblies, such as the electrolytic cell module itself. These five electrolytic stack assemblies can be load-dependent and flow-controlled. For example, each assembly consists of a 2MW electrolytic cell stack assembly with three stacks. These three stacks may have a common hydraulic compression system, are process-connected in parallel, electrical-connected in series, and therefore cannot be operated independently. Here, the supplied process water is decomposed into oxygen and hydrogen. Due to heat losses during electrolysis, the process water flows within the electrolytic assembly.

[0014] As the reactor assembly heats up, the narrow temperature band required for high-performance operation is controlled by the flow rate of electrolytic process water heading to the reactor for cooling.

[0015] Two separate two-phase flows emerge from the electrolyzer module: a water / oxygen flow, possibly at 0 bar, which is supplied to a two-stage O2 / H2O separation unit and a cooling unit. Another effluent from the electrolyzer module is a water / hydrogen flow, preferably at a higher pressure above 30 bar, which is directed to a downstream two-stage H2 / H2O separation unit. The two-stage O2 / H2O separation unit and / or the two-stage H2 / H2O separation unit comprises a coarse water-gas separation module and a subsequent fine water-gas separation module. To initiate and sustain the electrolysis reaction, a continuous direct current (DC) electrical energy supply is required to the electrolyzer assembly, provided by a dedicated power source (preferably implemented as a module).

[0016] In the water module, the main water pump supplies demineralized water for electrolysis to the five electrolyzer stack assemblies. Simultaneously, the feedwater circulation provides the necessary cooling capacity to compensate for temperature rises due to heat losses from electrolysis; therefore, more water is pumped through the stack than is needed just to compensate for the water demand of the electrolysis process. The main water pump, part of the water module, can be frequency-controlled to ensure load-dependent flow of demineralized water to the PEM stack. The main heat exchanger is also part of the water module. This main heat exchanger uses cooling water as the cooling medium. Depending on the heat load, process water is directed to the heat exchanger for cooling, or a constant cooling water flow can partially bypass the heat exchanger, or preferably, the cooling water flow to the heat exchanger is controlled according to the amount of heat to be removed from the process water. To ensure the high purity required in the process water loop, a portion of the process water flow from electrolysis is continuously recirculated to a water purification system implemented as a water purification module via a flow-controlled recirculation flow. This portion of the flow can be taken from the outlet flow of the main heat exchanger and can be directed through another centralized heat exchanger outside the water module. To ensure that particulate contamination of the PEM stack can be excluded, a dedicated process filter with a mesh size of preferably 10 μm (or 5 μm to 100 μm, specifically 5 μm to 20 μm, 30 μm, 40 μm, 50 μm or 100 μm) is integrated before the process water leaves the water module and enters the electrolysis cell module.

[0017] Modular structures reduce investment, maintenance, and development costs because standardized functional units (i.e., corresponding modules) with standardized interfaces can be combined to meet the specific requirements of a particular project. In at least one embodiment, at least some modules may be prefabricated partially or entirely off-site and then shipped to the construction site for final assembly. This high degree of pre-engineering and possible prefabrication significantly reduces assembly and testing costs and shortens project execution time. Modules can be designed such that they can be set up at test-proven locations and assembled on-site with minimal effort. Therefore, quality checks may already be performed off-site, reducing overall assembly time and the risk of delays. In at least one embodiment, the support frame may include a stackable self-supporting steel frame structure. This eliminates the need for foundation-specific equipment requirements. This reduces interdependencies during project execution and saves time and money during the assembly, transportation, and construction phases.

[0018] The module can be configured such that both internal (indoor, i.e., unaffected by atmospheric conditions) and external (outdoor, i.e., subjected to atmospheric conditions) installation of the module are possible without altering the geometry of the components and / or the module.

[0019] Decomposing the entire electrolysis system into functional units (i.e., modules) is a key element of standardized functional unit blocks. These functional unit blocks enable customized large-scale electrolysis systems to meet the specific requirements of different projects.

[0020] The present invention also relates to each of the modules individually pointed out above herein, namely the power supply module, the water supply module, the electrolytic cell module, the water-gas coarse separation module, and the water-gas fine separation module. Each of these modules can be used within such a modular electrolysis system, or in combination with one or more other modules among these modules.

[0021] As mentioned above, a constant amount of hydrogen cross-permeation will occur due to the pressure difference at the membrane (within the electrolyzer module). During normal production, the cross-permeated hydrogen will be diluted by the generated oxygen and will not form a hazardous atmosphere. Therefore, a minimum operating load can be defined to prevent the formation of an explosive mixture on or downstream of the anode side of the electrolyzer module.

[0022] For the operating mode that maintains hydrogen pressure and does not produce oxygen, dilution gas can be injected downstream of the electrolytic reactor to prevent the formation of an explosive atmosphere (the main explosion-proof measure).

[0023] Unlike the constant cross-permeability during normal operation, membrane defects are failure scenarios and are unpredictable. Detecting such defects, for example, by measuring the hydrogen concentration on the anode side, is unreliable and, moreover, too slow to initiate actions to prevent the consequences of the scenario. Therefore, primary explosion protection measures are not feasible for such defects. Completely eliminating all ignition sources (secondary explosion protection measures) is also impossible in the case of cross-permeability and considering the extremely low ignition energy of the hydrogen / oxygen mixture. However, ignition sources should be minimized as much as possible and eliminated if possible. This is particularly relevant to equipment downstream of the anode side of the electrolyzer module (i.e., the water-gas coarse separation module).

[0024] In the implementation plan, in addition to the interfaces and support framework already mentioned, the power module also includes a power transformer and at least one rectifier.

[0025] In the implementation scheme, the power module includes a standard shipping container (specifically a 20-foot or 40-foot container) as a support frame.

[0026] In implementations of the power module, at least one rectifier is configured as an active front-end rectifier. Such active front-end rectifiers, in particular in contrast to commonly used thyristor rectifiers, exhibit low harmonics and / or adjustable reactive power, which is beneficial for providing grid services (e.g., adjustable loads).

[0027] In the implementation of the power module, at least two rectifiers are connected to a single power transformer.

[0028] In the implementation scheme, in addition to the support frame and interface already mentioned, the water supply module also includes at least one pump for providing electrolytic feed water to an interface terminal configured to be connected to the electrolytic cell module, and for receiving cooling water from and / or providing cooling water to the interface terminal of any one or more modules configured to be connected to the system.

[0029] In the implementation scheme, the feedwater is also used as cooling water. This eliminates the need for any dedicated heat exchangers in the electrolytic cell module, thus saving costs and materials.

[0030] In one implementation, the water supply module includes a purification component for purifying one or more water streams before supplying them to the respective interface terminals.

[0031] In the implementation, the water supply module includes temperature control components for adjusting the heat in the cooling water and / or feed water. Specifically, a heat exchanger may be provided in the water supply module for removing heat from or adding heat to the corresponding water flow. The heat exchanger can be implemented as a compact and cost-effective plate heat exchanger. Depending on its specific configuration, the heat exchanger may utilize ambient heat or operate in conjunction with a heat pump (e.g., refrigerant circulation). Preferably, a secondary cooling or heating loop is used to operate the heat exchanger. This allows the use of regulated heat transfer fluids, such as regulated water or ethylene glycol. Therefore, deposits in the heat exchanger (e.g., due to insufficiently regulated cooling water) can be avoided, and more cost-effective control of cooling water flow rate can be achieved compared to process water control, while avoiding scaling.

[0032] In the implementation scheme, the water supply module includes a filter system, specifically a dual filter system with mesh sizes of 500 μm and 10 μm in the process water loop upstream of the interface terminals leading toward the electrolyzer module, to protect the sensitive membrane stack.

[0033] In the implementation, the water supply module can be configured to intermittently or continuously recirculate a portion of the water flow from the process water loop surrounding the electrolyzer module to the water purification system to prevent contaminant buildup. Such a water purification system can be integrated within the water supply module or provided as a separate module with its own dedicated support frame and interfaces. Specifically, the flow-controlled recirculated flow of the water purification system can be obtained from the outlet flow of the temperature control component mentioned in the implementation of the water supply module. Separating the water purification functionality from the electrolyzer module provides the benefit of better scalability.

[0034] The recirculation rate can be varied based on analytical parameters to ideally utilize a water treatment system (i.e., a water purification system and / or purification components) that provides the feedstock for hydrogen production. The required process analyzer (including the ability to adapt the recirculation rate to the existing water quality in the process water loop) can be part of the water supply module and / or electrolyzer module.

[0035] Then, purified water, also referred to here as process water for electrolysis, can be injected into the electrolytic cell module in a load-dependent and flow-controlled manner.

[0036] In the implementation scheme, some or all of the pumps in the modular system are controlled in a load-dependent manner to minimize power consumption in low-load scenarios. Additionally or alternatively, it is foreseeable that the recirculation rate can be adjusted based on continuous water analysis, thus optimizing water treatment usage, which also improves the efficiency of the overall system and specifically the efficiency of the water supply module.

[0037] In addition to the support frame and interface already mentioned, the electrolytic cell module also includes at least one water electrolytic cell stack having a plurality of electrolytic cells connected in series with each other, each electrolytic cell including a membrane that separates the anode and cathode of the electrolytic cell.

[0038] In one embodiment, the electrolytic cell module includes at least one stack compartment and a single valve compartment. The at least one stack compartment is used to house at least one electrolytic cell stack in each of the at least one compartments, and the single valve compartment houses a plurality of valves configured to control one or more fluid flows into and / or out of the at least one stack compartment.

[0039] In implementations of such electrolytic cell modules, each cell compartment has a length in the range of 2000 mm to 3500 mm and / or a width in the range of 750 mm to 1500 mm and / or a height in the range of 2000 mm to 3500 mm.

[0040] Specifically, the valve compartment may include a purging component configured to purge the internal volume of the valve surrounding the valve compartment with a purging airflow.

[0041] In an implementation of an electrolytic cell module, each electrolytic cell stack is configured to have a nominal power consumption in the range of 0.5MW to 5MW (e.g., 2MW), and / or the electrolytic cell module has a combined power consumption in the range of 0.5MW to 100MW (e.g., 20MW or 50MW).

[0042] In addition to the support frame and interface already mentioned, the water-gas coarse separation module according to the invention also includes a separator configured to separate a mixed-phase fluid containing water and gas supplied to the water-gas coarse separation module into: a water stream containing at least 70%, 80%, 90%, 95%, 98%, 99% or more than 99.5% of water contained in the mixed-phase fluid; and a gas stream containing at least 90%, 95%, 98%, 99%, 99.5% or more than 99.8% of any gas contained in the mixed-phase fluid, specifically oxygen and / or hydrogen.

[0043] In one embodiment of the water-gas coarse separation module, the mixed-phase fluid separation is achieved using a pipe with specific geometric boundary conditions. In other words, the water-gas coarse separation module is configured to provide mixed-phase fluid separation by means of its geometry.

[0044] In the implementation plan, the water-gas coarse separation module is configured to withstand an explosion within it.

[0045] Since the ignition of the aforementioned failure scenarios and the potential formation of hazardous atmospheres cannot be ruled out, the consequences are minimized to a level that ensures no personnel are harmed through constructive explosion-proof measures according to embodiments of the invention. Constructive explosion-proof measures are considered to refer to the design of relevant equipment and piping (connecting pipes between the electrolytic reactor and the water-gas pre-separation module, the water-gas pre-separation module, and O2 emission lines) to be explosion-proof / shock-proof. In the context of this invention, there is no distinction between explosion-proof pressure and explosion-proof pressure shock; both designs will accommodate explosions with or without permanent deformation. This ensures the mechanical integrity of the system. It eliminates the release of hazardous substances and potential harm to personnel. Consequently, the number of system parts requiring high mechanical strength through design measures is limited. This allows for thinner wall thicknesses in other components, and more specifically in all modules except the water-gas pre-separation module, and thus reduces the resources and costs required during the construction, transportation, and fabrication of individual modules.

[0046] In one implementation, the water-gas coarse separation module includes a liquid outlet facing the interface of the water-gas coarse separation module, wherein the liquid outlet is configured as a siphon.

[0047] In one embodiment of the invention, the water-gas coarse separation module is equipped with a vibration and / or acceleration sensor, which can be used to immediately detect an explosion event, and this information can be used for the control system of the electrolysis equipment.

[0048] In addition to the support frame and interface already mentioned, the water-air fine separation module according to the invention also includes a separator configured to separate the mixed fluid supplied to the water-air fine separation module into a water stream containing less than 1%, 0.3%, 0.1%, 0.03%, or less than 0.01% of gaseous and / or dissolved gaseous components of the mixed fluid, and an air stream containing at least 99.9% of gaseous and / or diluted gaseous components of the mixed fluid.

[0049] In one embodiment, the water-gas fine separation module includes a purging component configured to provide a hydrogen-free purge gas stream to the water-gas fine separation module, wherein the purge gas stream is extracted from the water-gas fine separation module together with the gas stream. Preferably, the purge gas stream is free of carbon dioxide (less than 200 ppm CO2, preferably less than 100 μm, more preferably 1 ppm to 100 ppm). The purge gas stream may be formed from gaseous nitrogen or CO2-free air.

[0050] In the implementation scheme, the water-air fine separation module may have an interface terminal for outputting at least a portion of the water flow to the water supply module for recirculation to other modules.

[0051] An additional interface terminal can be anticipated within the water-air fine separation module for receiving pretreated water flow from the water-air coarse separation module. Specifically, this interface terminal can be configured to receive the pretreated water flow by siphoning it from the water-air coarse separation module, thereby limiting pressure transmission in the event of an explosion within the water-air coarse separation module. This significantly reduces the mechanical stability requirements of the water-air fine separation module, and thus substantially reduces investment costs and resource consumption without compromising operational safety.

[0052] In one implementation, the gas stream output from the water-gas fine separation module may be additionally diluted with a hydrogen-free gas (e.g., nitrogen or air or a gas derived therefrom) to absolutely eliminate any possibility of an explosion downstream of the water-gas fine separation module. Optionally, the atmosphere surrounding the separator may also be purged with a hydrogen-free gas to dilute any potentially leaked hydrogen to a concentration well below that of an explosive mixture.

[0053] In the implementation scheme, the water-gas fine separation module is configured to separate gas microbubbles from the mixed fluid, specifically gases derived from the electrolysis of water within the electrolytic cell module. For this purpose, specialized equipment, for example, with structured plastic packing can be used.

[0054] Both the coarse and fine water-gas separation modules can operate under ambient or atmospheric pressure conditions (i.e., within a pressure range of 0.8 bar to 1.2 bar). The corresponding water flow and corresponding gas flow can both be output from the respective water-gas separation modules at these ambient or atmospheric pressure levels.

[0055] In the implementation scheme, where technically feasible, the modular electrolysis system is provided with interfaces for outputting and / or recovering usable process heat and making it available. The primary interfaces for this purpose are those for integrating process waste heat into a closed cooling / heating loop and for directly using process heat from safety purging or oxygen or hydrogen product streams within the HVAC system. Additionally, waste heat from the rectifier system can be made available within the HVAC system. Such HVAC systems can be configured as add-on modules (with corresponding support frames and interfaces) that are connected to the system via one or more interfaces from at least five modules of the system. This recovered process heat can be used either within or off the electrolysis system, i.e., output to consumers outside the electrolysis system. To recover this process heat, any module that generates a significant amount of heat (specifically, one or more of the water supply module, power supply module, and electrolysis cell module) can have one or more interface terminals within its respective interface for outputting heat from the corresponding module.

[0056] In addition to the modules already described (which can be considered the core modules of the system), additional modules may be provided to provide additional functionality and / or facilitate the installation of the system as a whole.

[0057] One such potential add-on module is a piping module in which up to 30% of the entire system piping can be pre-installed. The piping module may include dedicated conduits for specific fluids such as: water, specifically cooling water and / or process water; nitrogen and air, specifically carbon dioxide-free air and / or one or more electrolytic products: oxygen and / or hydrogen.

[0058] Another potential add-on module is the already mentioned HVAC system, which can be provided as a separate module and can be used, for example, to supply pre-conditioned air to one or more other modules (specifically core modules, such as the electrolytic cell module), in which such air can be used, for example, to purge the mentioned valve compartments.

[0059] In such HVAC modules, return air from the power module and associated electrical system (e.g., heated by losses in the rectifier) ​​can be directly recirculated back into the rectifier (to keep the supply temperature above the frosting temperature and above the condensation temperature) and / or used directly for the supply of the electrolytic cell modules (so that they also remain frost-free).

[0060] Direct conduit connections from the power module and electrolytic cell module to the air handling system (HVAC module) can be provided to prevent uncontrolled release into the space where the rectifier is located.

[0061] Return air from the electrolyzer module (e.g., heated by heat loss through piping) can be specifically used for direct recirculation back into the electrolyzer module's supply. In this case, the recirculation volume can be limited to an acceptable hydrogen concentration only when the supply air is present. The maximum amount of recirculated air can be determined through safety calculations, and the supply air can be monitored via a gas detector. A heat recovery system can be utilized between the exhaust gas from the electrolyzer module and the supply air from the HVAC module to the electrolyzer module and / or to the power module to maintain desired temperature levels and improve efficiency. In the context of the HVAC module, a closed-loop circuit system can be used. By using such a closed loop, any unwanted transfer of potentially hazardous air to the supply air stream is prevented, as the transfer medium acts as a barrier.

[0062] This design offers relevant advantages in terms of energy supply for heating and air conditioning in electrolysis systems. Typically, for safety reasons, electrolysis equipment requires a large amount of purge air (to dilute any hydrogen that may leak and / or reduce the extension of potentially hazardous atmosphere zones). Normally, conditioning these airflows to the required parameters (frost-free and below the typical maximum temperature of 35°C or 40°C) using conventional solutions consumes both thermal and electrical energy (in the case of cooling).

[0063] Using the HVAC modules described above, the additional heat required for operating equipment (even for external temperatures as low as -25°C and below) can be reduced to almost zero. If needed in hot climates, cooling energy can also be reduced through air recirculation and heat recovery systems via the electrolytic cell modules.

[0064] The oxygen stream released into the free atmosphere can optionally be combined with the purge gas stream exiting the electrolyzer module. As an example, the purge gas volumetric flow rate for each electrolyzer stack within the electrolyzer module can be constant, for example, 12,000 m³ / h, and can be limited by safety requirements. By combining the two streams (the purge gas used and the oxygen exhaust stream), fog cloud formation can be significantly reduced by lowering the relative humidity at the emission location. Specifically, a dedicated mixing device (e.g., a dedicated nozzle arrangement) can be used to combine the two streams, and this dedicated mixing device can be part of the HVAC module.

[0065] Another potential add-on module is an oxygen product post-processing module, which can interface with a water-gas coarse separation module and / or a water-gas fine separation module in the corresponding gas flow path. This oxygen product post-processing module may, for example, include a recombination reactor for removing hydrogen from the oxygen product stream, as well as product recycling and / or purification, to provide an oxygen product with desired quality specifications.

[0066] This type of oxygen product purification can also be achieved as a separate add-on module.

[0067] Another additional module can be provided for supplying purge gas to the electrolysis system. This purge gas supply module can be configured to provide purge gas, specifically carbon dioxide-free air, to prevent carbon dioxide contamination of the process water, as this would alter the pH of the process water and thus interfere with the electrolysis process. Removing carbon dioxide from the air is generally much less cost-intensive than providing any other suitable purge gas, such as nitrogen.

[0068] Other possible additional modules available in the context of the system provided by the present invention include a hydrogen purification module, a product liquefaction module, and a storage module, specifically a pressurization and / or liquid product storage module.

[0069] The advantages and other aspects of the invention are described below with reference to the accompanying drawings, in which...

[0070] Figure 1 An embodiment of the modular electrolysis system according to the present invention is illustrated schematically.

[0071] exist Figure 1 The implementation scheme of the modular electrolysis system is schematically depicted, and the modular electrolysis system is uniformly represented by 100.

[0072] System 100 includes multiple modules (110, 120, 130, 140, 150), each of which includes a support frame 101 and an interface 102 for connecting the modules to each other.

[0073] The support frame 101 may include, for example, carrier elements (such as steel beams), and optional wall panels and / or top and / or bottom panels. The support frame 101 may be specifically configured for the stacking assembly of modules, i.e., the support frame 101 of a module may be mechanically stable enough to support the weight of more than one module, and more specifically to support the combined weight of at least two modules, such that one module can be assembled on top of another module without any additional support structure.

[0074] In the illustrated embodiment, system 100 includes a power supply module 110, a water supply module 120, an electrolysis cell module 130, a water-gas coarse separation module 140, and a water-gas fine separation module 150. As already mentioned, more than these five modules can be combined to provide additional functionality, but these five modules are typically required for the electrolysis of water to produce hydrogen.

[0075] In the example shown, power module 110 receives electrical energy from outside the electrolysis system 100. For example, such input electrical energy may be provided in the form of high-voltage alternating current (AC), such as 10kV, 15kV, 20kV, or 30kV. The input current may be single-phase AC or multi-phase AC, specifically three-phase AC. The power module includes at least one transformer for converting the input AC to a different voltage, for example, to a voltage in the range of 0.5kV to 3kV, such as 1.5kV AC. Power module 110 also includes at least one rectifier, and more specifically, as many rectifiers as the electrolytic cell stack in electrolytic cell module 130. The rectifiers are configured to convert the AC from the transformer into direct current suitable for electrolysis. For example, the DC output from the power module via interface 102 downstream of the rectifier may be 1.5kV DC.

[0076] The power module interface 102 includes at least one power transfer interface terminal for electrically connecting the power module 110 to the electrolytic cell module 130.

[0077] Water supply module 120 is configured to provide cooling water and process water flows to other modules 110, 130, 140, and 150 via its interface 102. Water supply module 120 may be configured to receive water from outside system 100 (e.g., from a groundwater storage tank, rainwater harvesting tank, river, lake, or ocean) and to regulate the input water, for example, by removing contaminants such as dissolved salts and / or gases and / or suspended particles. Water supply module 120 may also be configured to receive return water from any of the other modules 110, 130, 140, and 150.

[0078] Electrolytic cell module 130 includes at least one pool stack, specifically, at least one pool stack is included in a defined compartment. Electrolytic cell module 130 is provided with direct current for electrolysis from power supply module 110 and process water to be electrolyzed from water supply module 120. Additionally, electrolytic cell module 130 receives cooling water (which may be the same as the process water) from water supply module 120. An oxygenated water stream (also referred to as a mixed fluid) is output from the anode side of electrolytic cell module 130 to water-gas coarse separation module 140 via interface 102.

[0079] In the water-gas coarse separation module 140, the mixed-phase fluid from the electrolytic cell module 130 is coarsely separated into gas and water streams. The gas stream can be discharged into the atmosphere surrounding the system 100 at a safe location (i.e., a location with good ventilation and no ignition source, ideally away from any other equipment). The gas stream can also be used as a byproduct, specifically after certain post-treatment.

[0080] In the illustrated implementation, the water-gas coarse separation module is mechanically stable enough to withstand the explosion of hydrogen and oxygen within it.

[0081] The water flow from the water-gas coarse separation module is preferably conveyed to the water-gas fine separation module 150 via a siphon line. The water-gas fine separation module 150 is configured to remove residual dilution gases or suspended gases from the water received from the water-gas coarse separation module 140. Typically, during water electrolysis, oxygen microbubbles can form in the process water. These microbubbles are relatively stable in the process water and are therefore difficult to separate from the water. The water-gas fine separation module 150 is configured to effectively remove such microbubbles. For this purpose, the water-gas fine separation module 150 may, for example, include a fluid tank into which the water flow from the water-gas coarse separation module 140 is conveyed. The tank may contain structured plastic packing that causes the microbubbles to aggregate, thereby forming larger bubbles, which combine themselves into an airflow by gravity. This airflow may also be discharged to a safe location or may be combined with the airflow from the water-gas coarse separation module 140 as a byproduct. Then, the water flow generated from the water-air fine separation module 150 can be recycled to the water supply module 120.

[0082] This embodiment or other embodiments of the present invention may further include one, more, or all of the following modules:

[0083] The fault ride-through support module provides power to the minimum required unit operation (equipment) to immediately restore rectifier operation after power restoration following a grid failure. As a preferred implementation of such a module, the flywheel is used in conjunction with a backup internal combustion engine generator. Another implementation is a battery-based backup system, with a typical power requirement of 2MW for a 100MW electrolysis unit, lasting from 1 to 20 seconds.

[0084] The PEM stack regeneration module provides and circulates a liquid through the stack to remove the ion-contaminated layer from the PTL (porous transfer layer). This type of method is used to extract cationic impurities from ionomers in an electrolyzer to restore performance during battery operation. A corresponding method has been described in: Babic et al., Journal of The Electrochemical Society, 166 (10) F610-F619 (2019), CO2-Assisted Regeneration of a Polymer Electrolyte Water Electrolyzer. A preferred embodiment of the PEM stack regeneration module consists of a valve assembly separating the stack to be regenerated from the process and another valve assembly connecting the stack regeneration module to a flush port on the stack. Alternative embodiments include a centralized arrangement of the module and connections of the stack and valve assembly to a manifold. Other embodiments may include a portable stack regeneration module that can be temporarily connected to the stack flush port for regeneration.

[0085] The PEM process water analyzer module preferably includes an analyzer set for measuring parameters such as conductivity, TOC, TIC, contamination index, and fluoride using a combined sample preparation plate, providing permanent monitoring of process water going to and from the electrolyzer stack per 10 MW. Another embodiment may be a centralized arrangement of process water analyzers using the analyzer set and combined sample preparation plate, and applicable to 20 MW, 30 MW, 40 MW, or 50 MW systems by switching between individual sample points using a minimal number of analyzers.

Claims

1. A modular electrolysis system (100) comprising multiple modules, wherein each of the multiple modules includes a support frame (101) and at least one interface (102), the at least one interface being accessible from outside the support frame and configured to connect the module to at least one of the remaining modules, the multiple modules comprising -Electrolysis cell module, -Water-gas coarse separation module (140), the water-gas coarse separation module is located downstream of the anode outlet of the electrolytic cell module, and - A water-gas fine separation module (150) is located downstream of the liquid outlet of the water-gas coarse separation module.

2. The system (100) according to claim 1, wherein the water-gas coarse separation module is configured to withstand an explosion therein.

3. The system (100) according to claim 1 or 2, wherein the water-gas coarse separation module includes a liquid outlet facing the interface of the water-gas fine separation module, wherein the liquid outlet is configured as a siphon.

4. The system (100) according to any one of the preceding claims, wherein the water-gas fine separation module includes a purging component configured to provide a hydrogen-free purging gas flow into the water-gas fine separation module, wherein the purging gas flow is extracted from the water-gas fine separation module together with the gas flow, and specifically wherein the purging gas flow guided into the water-gas fine separation module is free of carbon dioxide.

5. The system (100) according to any one of the preceding claims, wherein the plurality of modules further comprises at least one of the following: a power supply module (110), a water supply module (120), and an electrolytic cell module (130) comprising at least one electrolytic cell stack.

6. The system (100) according to claim 5, wherein the power supply module of the system includes a power transformer and at least one rectifier.

7. The system (100) of claim 6, wherein the power module includes a standard shipping container, specifically a 20-foot container or a 40-foot container, as the support frame, and / or wherein, in the power module, the at least one rectifier is configured as an active front-end rectifier, and / or wherein, In the power module, at least two rectifiers are connected to a single power transformer.

8. The system (100) according to any one of the preceding claims, wherein the water supply module includes at least one pump for providing electrolytic feed water to an interface terminal configured to be connected to an electrolytic cell module, and for receiving cooling water from and / or providing cooling water to the interface terminal of any one or more modules configured to be connected to the system.

9. The system (100) according to claim 8, wherein the water supply module includes a purification component for purifying one or more water streams before supplying the respective water streams to the respective interface terminals.

10. The system (100) according to any one of the preceding claims, wherein the electrolytic cell module comprises at least one water electrolytic cell stack having a plurality of electrolytic cells connected in series with each other, each electrolytic cell comprising a membrane separating the anode and cathode of the electrolytic cell.

11. The system (100) of claim 10, wherein the electrolytic cell module includes at least one stack compartment and a single valve compartment, the at least one stack compartment being configured to accommodate at least one electrolytic cell stack in each of the at least one compartment, and the single valve compartment accommodating a plurality of valves configured to control one or more fluid flows into and / or out of the at least one stack compartment.

12. The system (100) according to claim 11, wherein, In the electrolytic cell module, the valve compartment includes a purging component configured to purge the internal volume of the valve surrounding the valve compartment with a purging airflow.

13. The system according to claim 11 or 12, wherein, In the electrolytic cell module, each electrolytic cell stack is configured to have a nominal power consumption in the range of 0.5MW to 5MW, and / or the electrolytic cell module has a combined power consumption in the range of 0.5MW to 100MW.

14. The system (100) according to any one of the preceding claims, wherein the electrolytic cell module comprises a PEM electrolytic cell.

15. A water-gas coarse separation module configured for use with a system (100) according to any one of the preceding claims, the water-gas coarse separation module comprising a separator configured to separate a mixed fluid supplied to the water-gas coarse separation module into - A water flow containing at least 70%, 80%, 90%, 95%, 98%, 99%, or more than 99.5% water contained in the mixed fluid, and - An airflow containing at least 90%, 95%, 98%, 99%, 99.5%, or more than 99.8% of any gas contained in the mixed fluid, specifically oxygen and / or hydrogen. The water-gas coarse separation module is preferably configured to withstand an explosion therein, and / or preferably includes a liquid outlet facing the interface of the water-gas coarse separation module, wherein the liquid outlet is configured as a siphon.

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