Offshore electrolysis system and method for operating offshore electrolysis system

Abstract

The invention relates to an offshore electrolysis system (100) comprising a wind power generation device (1) having a platform (3) and an electrolysis device (5) arranged on the platform (3), the electrolysis device being coupled to the wind power generation device (1) for supplying an electrolysis current, and further comprising a heat supply device (7) coupled to the electrolysis device (5), the heat supply device having a combustion device (13), the fuel reservoir (15) is coupled to the heat supply device (7) in such a way that heat generated by the combustion device (13) can be transferred to the electrolysis device (5) during shutdown operation in order to maintain the temperature above the minimum temperature. The invention also relates to a corresponding method for operating an offshore electrolysis system (100), in which heat is generated by means of the heat supply device (7) and transferred to the electrolysis plant (5) during shutdown operation in order to maintain the temperature above the minimum temperature and prevent freezing of the water delivery components of the electrolysis plant (5).

Description

Technical Field

[0001] This invention relates to an offshore electrolysis system and a method for operating the offshore electrolysis system. Background Technology

[0002] An electrolysis device is a device that uses electric current to achieve the transformation (electrolysis) of substances. Depending on the various electrochemical electrolysis processes, there are many types of electrolysis devices, such as those used for water electrolysis. To supply direct current for electrolysis, the electrolysis device is connected to a production capacity device, thus forming an electrolysis system in this combination. Typically, an electrolysis device has multiple electrolytic cells, thereby enabling large-scale electrolysis power for the transformation of electrochemical substances under appropriate design.

[0003] Currently, hydrogen is produced from water, for example, through proton exchange membrane (PEM) electrolysis or alkaline electrolysis. Electrolysis equipment uses electrical energy to produce hydrogen and oxygen from supplied water. This process takes place in an electrolytic reactor consisting of multiple electrolytic cells. Water is introduced as a reactant into the electrolytic reactor under direct current voltage, and after flowing through the electrolytic cells, two fluid streams emerge, consisting of water and gas bubbles (O2 or H2).

[0004] Current research focuses on utilizing surplus energy from renewable energy sources to produce useful substances during periods of abundant sunshine and wind—when solar or wind power generation is above average. One such useful substance could be hydrogen produced through water electrolysis. Hydrogen can then be used to prepare so-called EE gases (renewable energy gases). EE gases are combustible gases obtained from renewable energy sources using electricity.

[0005] Hydrogen is a particularly environmentally friendly and sustainable energy carrier. It has the unique potential to achieve carbon dioxide-free energy systems, transportation, and most chemical industries. To achieve this, hydrogen must not be derived from fossil fuels but must be produced using renewable energy sources.

[0006] Wind power is a source of renewable energy. Especially with offshore wind power systems, large electrical outputs can be achieved. However, a challenge lies in overcoming the long distances between the wind turbines and the load. Therefore, energy should be delivered to the load with as little loss as possible. Hydrogen is very suitable as a transmission medium. For example, hydrogen can be transported in gaseous form through pipelines. An added advantage is that the pipelines guiding the hydrogen can also function as energy storage devices, as the internal pressure can vary within a certain range. Based on this idea, it is significant to directly produce hydrogen on-site at the energy acquisition site, i.e., to place offshore electrolysis equipment directly on or adjacent to offshore wind power systems. Therefore, current research focuses on offshore electrolysis systems, where the electrolysis equipment is directly mounted on the platform of the offshore wind power system. Here, the wind power system can be connected to the electrolysis equipment, forming a basically self-sufficient, nearly grid-independent electrolysis system, specifically designed for operation on isolated offshore islands.

[0007] Ideally, electrolysis systems, including combinations of wind power generation units and electrolysis equipment, can be constructed entirely without auxiliary connections to the power grid and are specifically designed for island operation. This is particularly suitable for electrolysis systems built in offshore areas to avoid long-distance connection paths to the coastal public power grid. Here, electrolysis equipment equipped with multiple electrolyzers is ideally placed directly near renewable energy sources, namely wind power generation units, thereby reducing or avoiding transformer and line losses. Therefore, there is currently significant research and development on offshore electrolysis systems equipped with electrolysis equipment, which are directly installed on platforms with offshore wind power generation units. For this type of coupling, whether "onshore" or "offshore," the equipment can operate without grid connection. However, during periods of no wind, weak winds, or scheduled maintenance of wind turbines, power cannot be supplied by generators or the grid without grid coupling.

[0008] In offshore electrolysis systems, it is crucial to prevent corrosion of the electrolysis equipment, as the presence of seawater leads to a significantly higher corrosion rate, jeopardizing the long-term uninterrupted operation of the equipment. In principle, offshore electrolysis equipment can be equipped with electrolytic cells housed in enclosed hulls, i.e., containers. This provides a degree of protection against external environmental influences. However, for operational needs, the electrolytic cells must be cooled during normal operation to continuously release the waste heat generated during electrolysis into the surrounding environment. Overall, thermal management of offshore electrolysis equipment presents significant challenges compared to onshore systems, specifically in terms of both the required cooling during normal operation and maintaining minimum temperatures during long-term shutdowns. In the latter case, especially during winter months when there is no wind or sunlight and wind power generation is shut down, it is essential to ensure adequate freeze protection for the water-containing electrolytic cells. Therefore, considering the cooling requirements of offshore electrolysis equipment during normal operation, at least one enclosed container structure should be installed, i.e., a sealing structure should be set up to protect the electrolyzer. This requires preventing both overheating and failure of the electrolyzer, and also avoiding harmful corrosion caused by exposure to marine salt. Consequently, in offshore electrolysis equipment, the interface and exchange between the electrolyzer and the environment are ultimately unavoidable, in order to properly dissipate the heat flow from the process during normal operation and ensure safe operation of the equipment.

[0009] Therefore, to protect the electrolyzer from environmental impacts, as mentioned above, it requires an enclosed structure, such as a container. PEM (proton exchange membrane) water electrolyzers must also operate using deionized water, especially high-purity water. Simultaneously, the internal temperature of the container must generally not fall below approximately 5°C. Otherwise, the water-containing supply components may freeze, causing the entire system to shut down. This would contradict the initial intention of offshore electrolysis systems with wind power generation to operate with minimal maintenance and self-sufficiency without grid coupling.

[0010] When the external temperature outside the encapsulation structure is below 5°C, heat will be transferred from the inside of the container to the outside through thermal conduction, convection, and radiation. At a minimum design temperature of -20°C in the external area, approximately 1 to 2 kW of heat energy is lost per hour from the corresponding container of the electrolysis equipment. However, heat loss also depends on the container's own insulation. Heat must be replenished to the container to maintain a relatively constant temperature of 5°C and reliably prevent freezing damage. During normal operation of the electrolysis equipment, i.e., when the electrolysis current is supplied by the wind power generation unit, the temperature inside the container can be maintained even in extremely low ambient temperatures because the electrolysis process provides sufficient waste heat.

[0011] Conversely, if no renewable electricity is available in extremely cold weather, for example due to lack of wind, or if wind power generation equipment needs to be shut down for possible unexpected maintenance, then other means must reliably provide the thermal energy required to maintain the temperature of the electrolysis equipment. Otherwise, the electrolyzers will face irreversible damage due to freezing, and the electrolytic cells installed in the equipment may even be completely rendered unusable. The water supply pipes between the containers and encapsulation structures must also be kept above the minimum temperature to prevent freezing. This also requires energy, which must be provided by other energy sources when there is no wind.

[0012] Existing solutions include using and configuring appropriately designed battery energy storage devices within the electrolysis system. These devices provide electrical power to maintain electric heating and temperature control. However, this approach has significant drawbacks. Firstly, the battery pack capacity is limited; secondly, installation space on offshore platforms is also significantly limited. In practice, for current applications on offshore wind power platforms, a relatively high battery capacity of at least 100 to 150 kWh is required to ensure temperature maintenance during extended shutdowns. This appears uneconomical given current battery technology. Especially at cold ambient temperatures, cold conditions weaken battery performance. Low temperatures increase electrolyte viscosity and make it more difficult to penetrate, resulting in fewer ions reaching the positive electrode and a sharp drop in battery power. Low temperatures also significantly slow down the reaction process within the battery, causing faster wear than normal. So-called battery energy storage systems (BESS) also suffer from high cost, large size, and heavy weight. Therefore, there is an urgent need for other, superior solutions for temperature maintenance during shutdowns of offshore electrolysis systems.

[0013] Another technically simpler solution is to integrate a diesel generator on the offshore platform for emergency power supply and heating. However, this solution has the drawback that the diesel fuel needs to be replenished regularly, thus failing to achieve the fundamental concept and goal of developing a reliable, CO2-free offshore electrolysis system. Summary of the Invention

[0014] Therefore, the object of this invention is to provide a marine electrolysis system that enables safe and environmentally friendly operation, while also being designed to be as self-sufficient and low-maintenance as possible. Another object is to provide a method for operating the marine electrolysis system.

[0015] According to the present invention, the objective proposed regarding the offshore electrolysis system is achieved by an offshore electrolysis system comprising a wind power generation unit having a platform and an electrolysis device arranged on the platform, the electrolysis device being connected to the wind power generation unit to supply electrolysis current, and further comprising a heating device coupled to the electrolysis device, the heating device having a combustion device, wherein a fuel reservoir is connected to the heating device so that, during shutdown operation, the heat generated by the combustion device can be transferred to the electrolysis device, thereby maintaining the temperature above a minimum temperature.

[0016] According to the present invention, the objective proposed regarding the operation method of the corresponding marine electrolysis system is achieved by the following operation method of the marine electrolysis system, wherein during shutdown operation, heat is generated by a heating device and transferred to the electrolysis equipment, thereby maintaining the temperature above the minimum temperature and preventing the water supply components of the electrolysis equipment from freezing.

[0017] The following advantages and preferred embodiments of the marine electrolysis system can be adapted to the operation method of the electrolysis system accordingly.

[0018] This invention is based on the understanding that the increasing number of installed, higher-power, and grid-independent offshore wind power generation devices, along with their ever-increasing power output, necessitates correspondingly higher-power electrolysis equipment. Therefore, it is anticipated that the power ratings and number of offshore electrolysis systems will increase significantly in the future.

[0019] The increasing demands for safe and environmentally friendly operation in marine environments must be considered. As efforts to scale up offshore electrolysis systems to larger scales in the open ocean become more focused, in addition to the environmental compatibility of such systems, the issue of achieving self-sufficiency—that is, operating independently of the power grid and utilizing 100% renewable wind energy for hydrogen production in isolated islands—has become a key point of discussion. Here, from an environmental perspective, operation with the lowest possible impact must be ensured. Therefore, providing a self-sufficient solution for reliably maintaining the temperature of the water supply components, especially the particularly sensitive submerged electrolyzers in PEM electrolysis equipment, is crucial, particularly for shutdown operations, especially when wind power generation fails and electrolysis current is interrupted.

[0020] The solution of this invention reliably ensures heating and temperature maintenance, even during winter months when there is no wind or light and the ambient temperature is low, posing a risk of freezing, without concern for the failure or damage of water supply components. This invention employs an integrated combustion-based heat preservation scheme in the marine electrolysis system, which possesses extremely high reliability and inherent fail-safe characteristics under harsh weather conditions and operating conditions. For this purpose, the heating system includes a combustion device and a fuel reservoir. The fuel reservoir can advantageously function as an element of the heating device, working in conjunction with and integrated with the electrolysis equipment, for example, mounted on a platform. The combustion device is connected to the fuel reservoir via fuel piping and can be designed, for example, as a combustion reactor, from which heat can be generated directly or indirectly and transferred to the water supply components of the electrolysis equipment that are at risk of freezing. This achieves a virtually maintenance-free marine electrolysis system, in which the risk of freezing damage due to freezing of the water supply components of the electrolysis equipment, especially the electrolytic cells and electrolytic pools, is reliably addressed. This results in a long service life and ensures immediate availability and operational readiness for resuming normal operation after shutdown. A fuel reservoir provides virtually unlimited standby capacity for maintenance-free fuel, whose energy can be utilized directly or indirectly as heat when needed by drawing fuel from the reservoir and converting it. The combustion device can be designed, for example, to implement the conversion through a typical combustion process based on the oxidation of fuel and its reaction with oxygen in the burner, generating heat directly through the flame. However, the combustion device can also be configured to perform an electrochemical conversion reaction. In this sense, the combustion device, as an element of a heating system, can be broadly understood as a reactor or reaction chamber into which fuel is fed and converted, ultimately generating heat in the heating system to maintain temperature and transfer it to the electrolysis equipment.

[0021] The marine electrolysis system of this invention advantageously identifies and overcomes, for the first time, the shortcomings of conventional heating schemes in grid-independent electrolysis systems. As previously mentioned, conventional heating schemes use large-capacity battery packs and diesel generators mounted on the platform to heat the electrolysis equipment. These schemes are not only extremely environmentally unfavorable but also expensive and cumbersome to maintain. In contrast, a combustion-based heating system can ensure temperature maintenance for days or even weeks in windless and sunless conditions, where heat transfer can be regulated by fuel consumption relative to the required minimum temperature to maintain that minimum temperature. Therefore, this heating system can be tailored to the needs of the electrolysis equipment, matching minimal heat emissions and minimal heat consumption to maintain the temperature, thus bridging long periods when wind power generation is unavailable for electrolysis.

[0022] In a particularly preferred design of an offshore electrolysis system, a product gas pipeline branches off from the electrolysis equipment, and a fuel storage tank is connected to this product gas pipeline, so that the product gas generated by electrolysis can be transported to the fuel storage tank during normal operation.

[0023] This allows for a particularly advantageous supply of fuel, which is then introduced into a fuel reservoir for storage. A key feature is that the fuel or its precursors can be generated as product gases during electrolysis and extracted from the electrolysis unit. Product gas pipelines allow the fuel reservoir to be replenished as needed or continuously, or refilled after shutdown, depending on its design and volume. This on-site supply of product gases provides a self-sufficient offshore electrolysis system that maintains temperature even during shutdown. This is particularly economically significant for the optimal island operation of offshore electrolysis systems.

[0024] In a particularly preferred design of an offshore electrolysis system, a product gas pipeline is connected to a conduit that serves as a fuel reservoir, and the product gas can be extracted from the conduit via a sump.

[0025] By connecting to and utilizing the pipeline, the pipeline itself can serve as a fuel storage device in addition to its conventional function of transporting product gases to the onshore receiving station, thus achieving a beneficial dual purpose. The product gas pipeline connects directly or indirectly to the pipeline, where the product gases are provided as pressurized products at the operating pressure within the pipeline. During shutdown operation, pressurized product gases can be extracted as needed via extraction lines on the pipeline and delivered to the combustion unit for heat generation. Due to the established and present operating pressure within the pipeline, the product gases can flow into the combustion unit automatically without the need for other delivery devices, such as pumps.

[0026] In a particularly preferred design of the marine electrolysis system, the product gas pipeline is connected to a gas storage tank, which constitutes a fuel reservoir from which the product gas can be extracted via a extraction pipeline.

[0027] Therefore, as an alternative to or supplement to pipelines, fuel storage devices in the form of gas storage units are provided. These gas storage units can be filled with pressurized product gas through product gas pipelines during normal operation and are designed as pressurized gas storage units. In this way, large quantities of product gas fuel can be stored at operating pressure. Additionally, a gas compressor can be connected to achieve higher filling pressures, thereby increasing the energy density within the gas storage unit. Furthermore, it is advantageous that the gas storage unit can operate independently of the pipeline and can be, for example, arranged on a platform and integrated into the electrolysis system. Therefore, even during pipeline failure, depressurization in the pipeline, or pipeline maintenance, shutdown operation can still be guaranteed, and redundancy is achieved through the gas storage unit, especially the pressurized gas storage unit.

[0028] In the preferred design of an offshore electrolysis system, the gas storage unit is located on a platform and / or installed inside the tower of a wind power generation unit.

[0029] This proposes a gas storage unit that is fully integrated into the offshore electrolysis system. Consequently, the gas storage unit can be located and operated near the heating unit (which serves as the load) and the electrolysis equipment (which generates the product gas). Therefore, the filling of the gas storage unit with product gas via product gas pipelines, the extraction of the stored product gas via extraction pipelines, and its delivery to the combustion unit can all be compactly achieved on the platform. The gas storage unit can be mounted on the platform or mounted below the platform and suspended and fixed thereto.

[0030] In addition to being installed on a platform, the tower of a wind power plant can also house a gas storage device.

[0031] In a particularly advantageous improvement and design for offshore electrolysis systems, a heating device is connected to and supplied by a gas storage tank, which serves as a fuel reservoir, installed inside the tower of a wind turbine. In this way, the gas storage tank can be simply formed or machined into a cavity inside the wind turbine tower. The gas storage tank is thus preferably installed deep below the water surface inside the tower, taking advantage of the relatively constant underwater ambient temperature and pressure conditions within the gas container. Simultaneously, introducing a gas storage tank into a cavity deep inside the tower has minimal impact on the tower structure and the mechanical stability of the nacelle housing the wind turbine. Furthermore, structural space can be provided or fully utilized for the pressurized gas storage tank, as this space would otherwise be unused. In this design, the gas storage tank does not occupy any area or structural space of the platform itself; the platform can be used for the electrolysis equipment and its components, without being limited by the heating device.

[0032] In advantageous designs of offshore electrolysis systems, the gas storage tank has a pressure vessel into which the product gas can be injected and stored. The gas storage tank is preferably designed as a tubular storage tank. Tubular storage tanks are designed for high gas pressures and, for example, can be easily installed below the platform and put into operation.

[0033] This provides a compact and easy-to-install gas storage device. Pressurized product gas storage can be carried out in steel containers or containers made of composite materials. Gaseous product gases supplied under high pressure, especially hydrogen (CGH2 = compressed hydrogen) produced by electrolysis equipment during normal operation, can be stored or transported in cylindrical containers made of steel. Lighter containers made of aluminum or plastic and covered with carbon fiber can also be used.

[0034] In a particularly preferred design of an offshore electrolysis system, the combustion unit has a fuel cell and a heating element, so that the fuel cell can provide current to drive the heating element during shutdown operation.

[0035] Fuel cells are connected to a gas storage tank via a pipe to achieve electrochemical conversion. Extracting electricity from a chemical energy carrier typically involves combustion, using the resulting hot gas to drive a heat engine and a subsequent generator. Thus, chemical energy is first converted into heat through combustion, then into mechanical work, and finally, the mechanical work generates electricity in the generator. Fuel cells, however, can achieve this conversion without converting it into heat or force, thus potentially offering higher efficiency. Unlike internal combustion engines, fuel cells directly convert chemical energy into electrical energy, avoiding the inherently lower efficiency of internal combustion engines. The theoretically achievable effective work is limited only by the free enthalpy of the chemical reaction, and therefore can exceed the efficiency of a heat engine (Carnot efficiency) coupled with a generator to produce electricity.

[0036] A fuel cell is a technological device that belongs to the category of electrical energy: it converts the chemical reaction energy of a continuously supplied fuel and oxidant into electrical energy. In marine electrolysis systems, hydrogen-oxygen fuel cells are preferred. Through water electrolysis, hydrogen is produced as a product gas in addition to oxygen in the electrolysis equipment. This hydrogen can be transported to a gas storage tank and used in the fuel cell process. The current generated by the fuel cell can be used to drive heating elements, thereby maintaining the temperature of the water supply system of the electrolysis equipment through heat transfer during shutdown. However, certain types of fuel cells can also use other fuels instead of hydrogen, especially methanol, butane, or natural gas. Fuel cells, like batteries, belong to the category of primary cells. Therefore, in principle, other fuels can also be stored in the fuel storage tank. Water electrolysis-based electrolysis equipment is particularly advantageous by integrating hydrogen-oxygen fuel cells into the heating unit, because the key reactant in the fuel cell process is generated as a product gas through electrolysis.

[0037] In another preferred design of the marine electrolysis system, current can be supplied by a fuel cell to maintain the control device of the electrolysis equipment.

[0038] Because fuel cells provide current, in addition to being used as heating current in heating devices, they can also be used for standby operation, particularly to continue powering the control devices and critical equipment components of electrolysis equipment.

[0039] Standby or standby operation refers to a state in which the actual working functions of an electrolysis unit are temporarily suspended, but can be reactivated at any time without preparation or a long waiting period. Maintaining standby status typically requires only a specific minimum power consumption reduction relative to normal operation.

[0040] In a particularly preferred design of an offshore electrolysis system, the combustion device has a gas burner, which allows the product gases to be burned and heat generated during shutdown operation.

[0041] Compared to fuel cells, combustion devices with gas burners have lower technical requirements and are equally reliable. Combustion heat is generated directly here and can be transferred to a medium such as water. The gas burner extends into a boiler with a circulating medium (especially water), and gaseous fuel is supplied from a gas storage tank via a drawdown line. Here, the circulating medium absorbs heat and is heated. The combustion heat from the gas burner can thus be used for temperature maintenance.

[0042] In a particularly preferred design of an offshore electrolysis system, the electrolysis equipment includes an electrolytic cell arranged in a container and a heat exchanger that, during normal operation, discharges the process heat generated by electrolysis from the container and, during shutdown operation, transfers the heat generated in the combustion unit.

[0043] This configuration enables particularly safe and environmentally friendly operation of offshore electrolysis equipment with containerized structures housing electrolyzers (e.g., PEM electrolyzers for hydrogen production). It also advantageously allows waste heat generated by the electrolysis process during normal operation to be additionally used, as needed, for temperature maintenance in optional thermal storage tanks during shutdown operations, rather than simply being released into the environment. Typically, during electrolysis operation, process heat is released into the environment from the container surrounding the electrolyzer and protected from weather effects and salinity intrusion. The optional thermal storage tank provides additional heat storage.

[0044] In this invention, the heat exchanger is advantageously designed to selectively dissipate the process heat generated during electrolysis from the container. This allows the heat exchanger to assist in cooling the container and, consequently, the electrolytic cell containing numerous electrolytic cells during normal operation. For this purpose, the heat exchanger can, for example, be connected to and thermally coupled to the coolant circuit driven by the coolant pump of the electrolytic cell on the primary side, thereby enabling targeted heat absorption, release, and potential subsequent utilization in the heating system on the secondary side of the heat exchanger. This advantageously enables the safe and environmentally friendly operation of a marine electrolysis system employing a closed container structure, which has an electrolytic cell (e.g., a PEM electrolytic cell for hydrogen production) arranged within the container, as well as coolant pumps arranged within the container and tightly flanged to the container. In the latter case, a housing unit is formed between the container and the flanged-connected coolant pump, thus the coolant pump is also understood to be arranged within the container. Through the closed cooling circuit, heat can be absorbed from the process heat generated during electrolysis at the equipment via the heat exchanger within the container. Multiple heat exchangers can also be installed here, with each specially configured heat exchanger being part of the heating system.

[0045] On the other hand, the heat exchanger is also designed to transfer the heat generated in the combustion device during shutdown operation, thereby achieving bidirectional heat exchange as needed, i.e., dual purpose: cooling function during normal operation, and temperature maintenance by starting the combustion device and generating heat during shutdown operation.

[0046] In a preferred design of an offshore electrolysis system, the electrolysis equipment has an electrolyzer for water electrolysis based on proton exchange membrane (PEM) electrolysis and / or alkaline electrolysis, with hydrogen as the product gas.

[0047] This allows for the combination of different electrolyzers in the offshore electrolysis system for water electrolysis, with adjustments made according to the load scheme. Alkaline electrolyzers operate in a quasi-steady-state at rated power under optimal conditions, while PEM electrolyzers have partial load capacity, particularly at lower partial loads below 30% of rated power. Both technologies produce hydrogen and oxygen as product gases. Hydrogen, besides being piped away and further utilized onshore as per regulations, can be partially stored in fuel reserves and used for temperature maintenance in the combustion unit when needed.

[0048] Another aspect of the present invention relates to a method for operating a corresponding marine electrolysis system.

[0049] Here, during shutdown operation, heat is generated by burning fuel in the combustion device using a heating device, and the generated heat is transferred to the electrolysis equipment to maintain the temperature above the minimum temperature and prevent the water supply components of the electrolysis equipment from freezing.

[0050] This method can be advantageously implemented in a self-sufficient manner, i.e., without requiring a power grid connection to the offshore electrolysis system. The electrolysis system is very advantageously designed for island operation, ensuring temperature maintenance even during periods of no wind and no light, and preventing freezing of water transport components.

[0051] In a preferred embodiment of the method, when the external temperature is below 5°C, temperature maintenance is initiated by converting fuel in a combustion device, where heat is generated and transferred to the water supply component of the electrolysis equipment, thereby achieving antifreeze protection.

[0052] To couple or transfer heat generated in the combustion unit to the freezing-prone water supply components of the electrolysis unit during shutdown operation, one or more heat exchangers may be used. These heat exchangers can simultaneously cool the electrolysis unit and dissipate process heat generated during electrolysis during normal operation; that is, they serve a bidirectional cooling purpose for the electrolysis unit by selectively dissipating process heat.

[0053] In another preferred embodiment of the method, hydrogen is converted as fuel in a fuel cell to generate an electric current, which is used to power the control device of the electrolysis equipment, thereby maintaining standby operation.

[0054] Here, hydrogen is generated as a product gas in the electrolysis unit and temporarily stored as needed, and is also used for shutdown operations. Advantageously, electrical energy is directly generated in the combustion unit equipped with a fuel cell. This electrical energy is used both as heating current for temperature maintenance and as system current for the standby operation of the electrical components of the electrolysis unit, particularly for the continued operation of the control devices. This allows for rapid restart after shutdown and immediate initiation of the normal operation startup procedure for the electrolysis system. Attached Figure Description

[0055] The implementation methods, features, and / or advantages of the marine electrolysis systems described herein also apply to the operating methods, and vice versa. Embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawings are shown in a schematic and highly simplified form:

[0056] Figure 1 An offshore electrolysis system with electrolysis equipment and wind power generation device is shown;

[0057] Figure 2 The thermal coupling of the heating device on the electrolysis equipment and its operation in a marine electrolysis system are illustrated.

[0058] Figure 3 A heating device is shown, in which the combustion device has a fuel cell;

[0059] Figure 4 A heating device is shown, in which the combustion device has a gas burner;

[0060] Figure 5 A schematic side view of an offshore electrolysis system with a fuel storage tank is shown. Detailed Implementation

[0061] The same reference numerals in the accompanying drawings have the same meaning.

[0062] Figure 1 The image shows an offshore electrolysis system 100. The offshore electrolysis system 100 includes an electrolysis unit 5 and a wind power generation device 1, the wind power generation device having a tower 19 and a turbine rotor, such as... Figure 1 As shown in the upper right section. In the lower region of tower 19, a platform 3 located above sea level 25 is fixed on tower 19 (see...). Figure 5 The platform is specifically designed and constructed to house the various equipment components required for the intended operation of the offshore electrolysis system 100. These equipment components are... Figure 1 The lower part is shown as an example in a magnified view:

[0063] An electrolysis unit 5 is installed on platform 3 and systematically connected to the wind power generation unit 1 to form an offshore electrolysis system 100. For this purpose, a container 9 is specifically provided on platform 3, housing electrolysis units (not shown in detail), such as individual electrolyzers, thereby protecting the particularly sensitive functional components of the electrolysis unit 5 from weather conditions. Each container 9 on platform 3 contains and protectively houses control devices 27, or so-called "peripheral equipment." This is a selected container 9, typically dedicated solely to housing and operating these control devices 27 and any other possible auxiliary systems for the electrolysis unit 5. The electrolyzers for electrochemical conversion are arranged within containers 9 dedicated to this purpose. Other components or equipment housings in the container 9 may also include storage containers for the electrolyte used to operate the electrolyzers, or, particularly, deionized water or potassium hydroxide solutions, especially in the case of the PEM (proton exchange membrane) of the electrolyzers or, optionally, alkaline water electrolysis.

[0064] In this scheme, the wind power generation device 1 preferably does not have a grid connection or grid coupling, but instead directly supplies power to the electrolysis equipment 5 using received wind energy in a self-sufficient offshore electrolysis system 100. The electrolysis equipment 5 is configured to produce preferably green hydrogen through water electrolysis. Therefore, the offshore electrolysis system 100 is configured to operate in an isolated manner, independent of the power grid, and is suitable for self-sufficient applications in remote offshore areas. Therefore, the wind power generation device 1 is an offshore wind turbine. Figure 1 and Figure 5 Unlike the illustration, the mechanism proposed in this invention for improving the heating and temperature maintenance of the offshore electrolysis system 100 can also be directly applied to "land-based" equipment.

[0065] The strategy of supplying the electrolysis equipment 5 using multiple containers 9, preferably ISO containers, effectively ensures a simple maintenance and repair process, while simultaneously protecting equipment components from the effects of climate and weather, corrosion, and harmful mechanical influences during operation. The electrolysis system 100 is particularly vulnerable under freezing conditions when the wind power generation unit 1 cannot supply power to the electrolysis system. Consequently, the water supply system of the electrolysis equipment 5 faces an urgent risk of freezing, especially during prolonged periods without wind or sunlight, and in situations where severe freezing occurs during shutdown.

[0066] The present invention addresses this problem by means of a heating device 7, which is advantageously integrated into the electrolysis system 100. Therefore, as... Figure 1 As exemplarily shown, the heating device 7 may be installed in an selected container 9 of the offshore electrolysis system 100, or the container 9 may contain specific equipment components or functional elements of the heating device 7. The heating device 7 is here coupled to the electrolysis equipment 5 and configured to transfer heat to the electrolysis equipment 5 during shutdown operation, thereby maintaining the temperature of the water supply system above a minimum temperature.

[0067] The thermal coupling of the heating device 7 to the electrolysis equipment 5 and its operation in the marine electrolysis system 100 will be achieved by means of... Figure 2 Further explanation: The heating device 7 includes a combustion device 13, which supplies fuel from a fuel reservoir 15 via an extraction pipe 21. The fuel reservoir 15 is connected to the electrolysis unit 5 via a product gas pipe 17. During normal operation of the electrolysis unit 5, hydrogen H2 is produced as a product gas 23. Hydrogen H2 is produced from water, for example, by proton exchange membrane (PEM) electrolysis or alkaline electrolysis. The electrolysis unit 5 uses electrical energy to produce hydrogen H2 and oxygen O2 from the supplied water. This process takes place in an electrolysis stack consisting of multiple electrolytic cells. Water is introduced as a reactant into the electrolysis stack under DC voltage, wherein two fluid streams, consisting of water and gas bubbles (O2 or H2), flow out after passing through the electrolysis cells, and the two product gases are separated and discharged through their respective product gas pipes 17. During normal operation of the electrolysis unit 5, the fuel reservoir 15 is filled with hydrogen H2, thereby providing hydrogen H2 as fuel and storing it for necessary shutdown operations. The fuel reservoir can be constructed as a gas reservoir 39, such as a tubular reservoir, which, if necessary, is filled with hydrogen (H2) generated from the electrolysis unit 5 at a high reservoir pressure by recompression. Thus, the gas reservoir 39 can be constructed and designed in a simple manner as an integrated component of the offshore electrolysis system 100 and, for example, fixed to its supporting structure or arranged in the container 9. The combustion unit 13 is thermally coupled to the electrolysis unit 5 via a heat exchanger 11. Supply lines 47a and return lines 47b are provided here, achieving thermal coupling and transferring heat to the electrolysis unit 5 via the heat exchanger 11 to maintain its temperature. The heat exchanger 11 is supplied with heat from combustion on the primary side, wherein the heat generated in the combustion unit 13 during shutdown operation is first transferred to a suitable heat exchange medium in the container, such as circulating water. On the secondary side, the circulating process water in the electrolysis unit can absorb the heat generated in the combustion unit 13 via the heat exchanger 11 to maintain a minimum temperature. This reliably prevents the water supply components of the electrolysis unit 5 from freezing. When the wind power generation unit 1 stops generating electricity (e.g., due to lack of wind and sunlight) and the external temperature is below 5°C, shutdown operation is initiated by converting the hydrogen (H2) stored in the fuel accumulator in the combustion unit 13. The combustion unit 13 can be configured as, for example, an open-flame heated boiler or an electric heated boiler. Therefore, for heat generation, an electrically operated water heater or a gas-operated water heater can be used, which is coupled to the heat exchanger 11 on the primary side.

[0068] The following will use Figure 3 and Figure 4 These schemes are shown and explained. To this end, Figure 3A heating device 7 is shown, in which a combustion device 13 has a fuel cell 41 and a heating element 43. The fuel cell 41 uses hydrogen (H2) and oxygen (O2) as reactants. Hydrogen (H2) is drawn from a fuel reservoir 15 via a drawdown line 21 and delivered to the cathode side. Correspondingly, pure oxygen (O2) can be delivered from a spare reservoir or purified ambient air via the drawdown line 21 to the anode side of the fuel cell 41. The fuel cell 41 provides electrical power for heating in the heating device 7. During shutdown operation, the fuel cell 41 supplies current to the heating element 43, thereby achieving resistance heating. The generated resistance heat can be... Figure 2 The heat exchange medium is heated on the primary side and delivered to heat exchanger 11. Alternatively, the heating element 43 can be directly connected to the process water circulation loop of the electrolysis unit 5 via thermal loop technology, for example, by arranging the heating element 43 within the heat exchanger 11 or by extending a heating coil into it. In this way, a separate heat exchange medium is not required, as the primary loop is eliminated. Temperature maintenance is also achieved through the supply line 47a and return line 47b of the heat exchanger 11. Simultaneously, electrical power from the fuel cell 41 can be supplied to the electrical system of the electrolysis unit 5, such as the control device 27, to maintain standby operation.

[0069] In contrast, Figure 4 Heating device 7 is shown, in which combustion device 13 has a gas burner 45 suitable for burning hydrogen H2. In this way, water electrolysis product gas 23 in gas storage tank 39 can also be advantageously used. Product gas 23 is generated and stored in gas storage tank 39 during normal operation of electrolysis unit 5 and is stored therefor later use. Hydrogen H2, as product gas 23, is supplied to gas burner 45 via extraction line 21, and the hydrogen H2 is burned together with oxygen O2 or combustion air L stored in the electrolysis. The released heat of combustion is transferred in the hydrogen-burning heating boiler to the heat exchange medium in the water supply line and delivered on the primary side to heat exchanger 11, where it exchanges heat with the process water to be heated in the electrolysis. Heat transfer is achieved by the circulation or rotation of process water via supply line 47a and return line 47b. A circulation pump is provided for this purpose, powered by a miniaturized and normally rechargeable battery storage unit.

[0070] exist Figure 3 and Figure 4In both embodiments of the heating device 7 shown, the heat exchanger 11 can be additionally designed for bidirectional operation, i.e., during normal operation, it can also be used to discharge process heat from the electrolysis process from the container 9, and during shutdown operation, it can maintain temperature by transferring heat generated in the combustion device 13 to the water supply components and system of the electrolysis unit 5. For example, process heat can be discharged via a separate coolant circuit (not shown in detail), into which the heat exchanger 11 is additionally connected. The coolant circuit is activated during normal operation for cooling purposes. During shutdown operation, the coolant circuit is closed, wherein heat generated in the combustion device 13 is transferred as described. In this way, the marine electrolysis system 100 with the heating device 7 is suitable for switching from cooling operation to heating operation.

[0071] Figure 5 A schematic side view of an offshore electrolysis system 100 is shown, comprising a wind power generation unit 1, a platform 3, and an electrolysis unit 5 arranged on the platform 3. The platform is fixed to a tower 19 in a surface area 29 above sea level 25. The electrolysis unit 5 comprises multiple containers 9, each containing at least one electrolysis cell. The offshore electrolysis system 100 shown here is advantageously equipped with an integrated combustion-based heating unit 7. The heating unit 7 has a fuel reservoir 15 connected to it, so that the hydrogen (H2) obtained from electrolysis can be stored in the fuel reservoir 15 and converted as fuel for heat generation when needed. The heating unit 7 is arranged on the platform 3, and here it can also be installed together with the mechanism of the electrolysis unit 5, such as the electrolysis cell, in one of the containers 9. The tower 19 extends from the surface area 29 to the underwater area 31 and is securely anchored to the seabed 35 via a base 33.

[0072] Fuel reservoir 15 is designed as a gas reservoir 39, so that product gas 23 (here, hydrogen H2) can be stored in gas reservoir 39 at storage pressure. Gas reservoir 39 is advantageously designed with a pressure-resistant container, for example, constructed as multiple hydrogen pipe reservoirs. Gas reservoir 39 is suspended and fixed below platform 3, thus not occupying space on the platform. In addition, a cavity is formed within the tower 19 of the wind power generation unit 1 (in this embodiment, the cavity extends into the base 33 below sea level 25) and has a corresponding storage volume for hydrogen H2. Pressure-resistant and hydrogen-sealed gas reservoir 39 is installed within this cavity. Therefore, during normal operation of the offshore electrolysis system 100, hydrogen H2 produced during electrolysis, as product gas 23, can be stored in gas reservoir 39 under pressure and fill gas reservoir 39. It is injected into gas reservoir 39 through product gas pipeline 17 or a corresponding branch pipeline of product gas pipeline 17. Simultaneously, platform 3 is equipped with a connection unit connected to pipe 37 for outputting product gas 23. This connection unit is connected to or supplied through product gas pipeline 17. Pipeline 37 is led off from platform 3, submerged in underwater area 31, and guided to land via seabed 35. Product gas 23 can be received and further processed on land. Therefore, during normal operation of electrolysis system 100, product gas 23 (here, hydrogen H2) can be fed into pipeline 37 under pipeline pressure and transported to land. Product gas pipeline 17 is connected to pipeline 37, whereby pipeline 37 functions as gas storage 39. Thus, fuel storage 15 is simultaneously provided through pipeline 37, and product gas 23 can be extracted from fuel storage 15 as needed at the connection unit via extraction pipeline 21. Hydrogen H2 is extracted from the gas storage tank 39 or the pipeline 37 via the extraction pipeline 21. This extraction pipeline supplies the combustion-based heating device 7 when the electrolysis system is shut down, so that the generated heat can be transferred to the electrolysis equipment 5, thereby maintaining the temperature above the minimum temperature and achieving antifreeze protection.

Claims

1. An offshore electrolysis system (100) comprising a wind power generation unit (1) having a platform (3) and an electrolysis device (5) arranged on the platform (3), the electrolysis device being connected to the wind power generation unit (1) to supply electrolysis current, the offshore electrolysis system further comprising a heating device (7) coupled to the electrolysis device (5), the heating device having a combustion device (13), wherein, The fuel reservoir (15) is connected to the heating device (7) so that the heat generated by the combustion device (13) can be transferred to the electrolysis device (5) during shutdown operation, thereby keeping the temperature above the minimum temperature.

2. The marine electrolysis system (100) according to claim 1, characterized in that, A product gas pipeline (17) branches off from the electrolysis equipment (5), and a fuel reservoir (15) is connected to the product gas pipeline, so that the product gas (23) generated by electrolysis can be delivered to the fuel reservoir (15) during normal operation.

3. The marine electrolysis system (100) according to claim 1 or 2, characterized in that, The product gas pipeline (17) is connected to the pipeline (37), wherein the pipeline (37) constitutes a fuel reservoir (15), and the product gas (23) can be extracted from the pipeline through the extraction pipeline (21).

4. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The product gas pipeline (17) is connected to the gas storage tank (39), which constitutes the fuel storage tank (15). Product gas can be extracted from the fuel storage tank through the extraction pipeline (21).

5. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The gas storage unit (39) is located on the platform (3) and / or installed in the tower (19) of the wind power generation unit (1).

6. The marine electrolysis system (100) according to claim 5, characterized in that, The gas storage unit (39) is designed as a tubular storage unit.

7. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The combustion device (13) has a fuel cell (41) and a heating element (43), so that the fuel cell (41) can provide current to drive the heating element (43) during shutdown operation.

8. The marine electrolysis system (100) according to claim 7, characterized in that, A control device (27) that can be powered by a fuel cell (41) to maintain the electrolysis equipment (5).

9. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The combustion device (13) has a gas burner (45) so that the product gas (23) can be burned in the gas burner (45) and heat is generated during shutdown operation.

10. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The electrolysis equipment (5) includes an electrolytic cell arranged in a container (9) and a heat exchanger (11) which is used to remove the process heat generated by electrolysis from the container (9) during normal operation and to transfer the heat generated in the combustion device (13) during shutdown operation.

11. The marine electrolysis system (100) according to any one of the preceding claims, characterized in that, The electrolysis equipment (5) has an electrolytic cell for water electrolysis, which is based on proton exchange membrane (PEM) electrolysis or alkaline electrolysis, and the product gas is hydrogen (H2).

12. A method of operating the marine electrolysis system (100) according to any one of the preceding claims, wherein, During shutdown operation, heat is generated by the heating device (7) and transferred to the electrolysis equipment (5), thereby maintaining the temperature above the minimum temperature and preventing the water supply components of the electrolysis equipment (5) from freezing.

13. The method according to claim 12, characterized in that, When the external temperature is below 5°C, the temperature is maintained by converting the fuel in the combustion device (13), where heat is generated and transferred to the water supply component of the electrolysis device (5), thereby achieving antifreeze protection.

14. The method according to claim 13, characterized in that, In the fuel cell (41), hydrogen is converted as fuel to generate an electric current, which is used to power the control device (27) of the electrolysis device (5) to maintain standby operation.

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