Offshore electrolysis plant and method for operating an offshore electrolysis plant

Abstract

The invention relates to an offshore electrolysis plant (20), comprising an electrolyzer, which is disposed in a container (2), and a heat exchanger (4), which is designed to absorb process heat from the electrolysis and to discharge said process heat out of the container (2) in a closed coolant circuit (3). A coolant pump (5) for conveying the coolant in the coolant circuit (3) is disposed in the container (2). The invention also relates to a method for operating an offshore electrolysis plant (20) having an electrolyzer disposed in a container (2). In said method, in order to absorb process heat from the electrolysis and to discharge said process heat out of the container (2), coolant is conducted in a closed coolant circuit (3), wherein a coolant pump (5) disposed in the container (2) is operated.

Description

[0001] The invention relates to an offshore electrolysis plant and a method for operating an offshore electrolysis plant.

[0002] An electrolysis plant is a device that uses electrical current to transform a substance (electrolysis). Due to the variety of different electrochemical electrolysis processes, there are also a variety of electrolysis plants, such as an electrolysis plant for water electrolysis.

[0003] Today, hydrogen is produced from water using processes such as proton exchange membrane (PEM) electrolysis or alkaline electrolysis. These electrolysis systems use electrical energy to produce hydrogen and oxygen from the supplied water. This process takes place in an electrolysis stack composed of several electrolysis cells. Water is introduced as the reactant into the electrolysis stack, which is under DC voltage. After passing through the electrolysis cells, two fluid streams emerge, consisting of water and gas bubbles (O2 and H2, respectively).

[0004] Current considerations are to use surplus energy from renewable energy sources during periods of abundant sun and wind, i.e., when solar or wind power generation is above average, to generate valuable materials. One such valuable material could be hydrogen, which is produced by water electrolysis plants. Hydrogen can be used, for example, to produce so-called renewable gas.

[0005] A renewable energy gas is a combustible gas that is produced using electrical energy from renewable sources.

[0006] Hydrogen represents a particularly environmentally friendly and sustainable energy source. It has the unique potential to realize energy systems, transport, and large parts of the chemical industry without CO2 emissions. For this to succeed, however, the hydrogen cannot come from fossil sources, but must be produced using renewable energy.

[0007] One source of renewable energy is wind power. Large electrical outputs can be achieved, particularly with coastal, so-called offshore wind turbines. However, the challenge is that consumers have to be located at great distances. The energy must therefore be transported to the consumer with as little loss as possible. Hydrogen is an ideal transport medium. It can be transported in gaseous form, for example, via pipelines. A positive side effect is that a hydrogen-carrying pipeline can also serve as an energy storage device, since the internal pressure can be varied within certain limits. For this reason, it is particularly interesting to produce hydrogen directly at the site of energy generation, i.e. to locate offshore electrolysis plants directly at or in the immediate vicinity of offshore wind turbines.

[0008] In offshore electrolysis plants, special attention must be paid to preventing corrosion, as the presence of saltwater can lead to significantly higher corrosion rates, jeopardizing the long-term uninterrupted operation of an electrolysis plant. In principle, offshore electrolysis plants can be equipped with electrolyzers and housed within closed enclosures, known as containers. This can provide a certain degree of protection for the electrolyzer from external environmental influences. However, for operational reasons, the electrolyzer must be cooled to dissipate the waste heat generated during the electrolysis process into the environment.

[0009] Efficient cooling and waste heat utilization of an onshore electrolysis plant is described, for example, in EP 2 623 640 A1. The efficiency of an electrolyzer for generating hydrogen and oxygen by decomposing water is increased by storing waste heat generated in the electrolyzer in a heat transfer medium, feeding the heat transfer medium to a water treatment plant, and producing deionized water from raw water in the water treatment plant using the waste heat. The heat transfer medium is pumped in a closed circuit between the electrolyzer and the water treatment plant. A respective heat exchanger ensures the absorption and removal of heat from the electrolysis plant housing and the corresponding heat transfer and supply to the water treatment plant.

[0010] In comparison, the cooling requirements during operation of offshore electrolysis plants are particularly important due to their closed container design, i.e., the enclosure and protection of the electrolyzer, to prevent overheating and failure. Thus, in an offshore electrolysis plant, an interface between the electrolyzer and the environment is ultimately unavoidable in order to adequately dissipate the process heat flow and enable safe operation. At the same time, environmental considerations in the maritime sector are significant, particularly regulatory requirements for the protection of marine fauna and flora.

[0011] The object of the present invention is therefore to provide an offshore electrolysis plant that enables safe and environmentally friendly operation. A further object is to provide a method for operating an offshore electrolysis plant.

[0012] The object directed to an offshore electrolysis plant is achieved according to the invention by an offshore electrolysis plant comprising an electrolyzer arranged in a container, as well as a heat exchanger which is designed for the heat absorption and dissipation of process heat from the electrolysis into a closed coolant circuit from the container, wherein a coolant pump for conveying the coolant in the coolant circuit is arranged in the container.

[0013] The object directed to a method for operating an offshore electrolysis plant is achieved according to the invention by a method for operating an offshore electrolysis plant with an electrolyzer arranged in a container, in which coolant is guided in a closed coolant circuit for the heat absorption and dissipation of process heat from the electrolysis from the container, wherein a coolant pump arranged in the container is operated.

[0014] The advantages and preferred configurations listed below with regard to the offshore electrolysis plant can be applied analogously to the method for operating the electrolysis plant.

[0015] The invention is based on the realization that the increasingly installed, more powerful offshore wind turbines and their growing electrical generation capacity require correspondingly more powerful electrolysis systems. It is therefore expected that the power class of an offshore electrolysis system and their number will increase significantly in the future. The associated, increasing demands for safe and environmentally friendly operation in the maritime environment must be taken into account. Due to the scaling efforts towards larger offshore electrolysis systems, the issue of environmental compatibility is becoming a focus of discussion. Operation with the least possible impact from an environmental perspective must be ensured. Solving the cooling problem for operation is therefore of particular importance, while simultaneously ensuring operational reliability and the performance of the offshore electrolysis system.

[0016] The offshore electrolysis plant according to the invention recognizes and overcomes for the first time the disadvantages of conventional open cooling approaches for the cooling medium. For example, a concept in which seawater is pumped directly from the sea and extracted as a cooling medium for a heat exchanger. After being exposed to the process heat of the offshore electrolysis plant and heat transfer to the seawater, the seawater is immediately returned to the sea. This proves to be highly disadvantageous from an environmental perspective and also requires intensive maintenance.

[0017] Other cooling concepts using ambient air require large heat exchange surfaces with the atmosphere and extensive fan systems or blowers for cooling air supply to achieve the required cooling capacity. Such systems in offshore applications are highly susceptible to corrosion failure due to the direct exposure to saline aerosols in maritime environments and require significant maintenance.

[0018] The invention overcomes these disadvantages and enables safe and environmentally friendly operation of an offshore electrolysis plant in a closed container design with an electrolyzer arranged in the container, for example a PEM electrolyzer for hydrogen production, and with a coolant pump arranged in the container or a coolant pump tightly flanged to the container. In the latter case, a housing unit is formed between the container and the flanged coolant pump, so that, in the sense understood, the coolant pump is also arranged in the container. With the closed cooling circuit, the heat absorption of the process heat from the electrolysis at the plant is achieved via the heat exchanger in the container.Both the use of seawater for cooling purposes, which involves sucking in and recirculating it, and the significant corrosion problems associated with air cooling during open cooling operations at sea are avoided. The invention takes a different approach than conventional offshore systems with open cooling.

[0019] In particular, the problems described above are avoided by not sucking in seawater and instead using a closed coolant circuit. Foreign matter cannot be sucked in, and undesirable inorganic layers or biofouling cannot form inside the heat exchanger, which increases operational reliability. In particular, no heated water is discharged into the environment. A further advantage is that, in addition to (fresh) water, other particularly suitable cooling media or additives can be used in the closed cooling circuit, which can then significantly reduce the required heat transfer capacity or the design of the surfaces required for heat absorption of the process heat from the container at a high temperature level, its dissipation, and ultimately transfer to a suitable heat sink.

[0020] In the offshore electrolysis plant, a coolant pump is arranged in the coolant circuit to pump the coolant. The coolant pump is designed according to the cooling capacity. To protect it from the effects of the weather, the coolant pump is therefore housed in the container itself, for example near the electrolyzer of the offshore electrolysis plant to be cooled. In principle, a fixed coupling is also possible by tightly flanging the coolant pump directly to the container, for example from the outside, so that an integral housing unit of the coolant pump and the container is then formed. The protection and cooling concept should therefore be understood within the scope of the invention such that even if the coolant pump is flanged, screwed or otherwise directly coupled to the container, the electrolyzer and the coolant pump are considered to be housed in the same container, forming a housing unit.This is particularly advantageous for maintenance and overhaul purposes on the coolant pump, as it allows for easier access to the coolant pump from the outside if necessary. This protects particularly sensitive components, such as the electrolyzer, heat exchanger, and coolant pump, for offshore use, and the offshore electrolysis system is specially designed for offshore operation.

[0021] According to a particularly preferred embodiment, a heat exchanger with a correspondingly large-area heat exchanger surface, which can be immersed in the sea, is provided in the closed coolant circuit for the heat dissipation of the process heat absorbed by the coolant. By integrating a heat exchanger designed with a correspondingly large-area heat exchanger surface into the closed cooling circuit, a particularly effective coupling to the selected heat sink, the seawater, is achieved, and the immersion capability enables heat transfer of the dissipated process heat from the large-area heat exchanger to the seawater. The coolant circuit with the cooling medium, which is independent of the seawater, proves to be particularly advantageous here.

[0022] The invention thus envisages the use of seawater as a heat sink in a virtually large reservoir of cooling medium, with a closed cooling circuit allowing only the heat to be released by the heat exchanger immersed in the sea. This enables high cooling capacities for electrolysis, and large heat flows from powerful offshore electrolyzers to be transferred to the seawater via the coolant. The environmental impact of this design is minimal, particularly since the material decoupling of the coolant and seawater is provided. To enable the heat exchanger to be immersed in seawater, suitably configured swivel devices and / or lifting gear are provided on the offshore electrolysis plant, enabling the heat exchanger to be moved in and out of the seawater.

[0023] Through appropriate thermal engineering, the generally relatively large exchange surface for the large-area heat exchanger can be advantageously dimensioned and designed to meet the required cooling capacity. Unlike open cooling concepts, it is no longer necessary to extract seawater via pumps, actively convey it to the water surface, and directly feed it to the offshore electrolysis plant for cooling. Instead, heat is removed indirectly via the large-area heat exchanger through convection in the seawater.

[0024] To provide a large heat transfer surface, the heat exchanger, in particular the large-area heat exchanger, advantageously has a pipe which is designed with ribs and / or fins on the coolant-carrying pipe outer surface and / or is guided in a plurality of pipe bends.

[0025] These design measures involving a pipe or pipe bundle are taken to increase the surface area for efficient heat transfer. Various options are possible, such as designing the heat exchanger as a meandering and / or finned pipe. Furthermore, as in a shell-and-tube heat exchanger, the coolant flow rate can be distributed across several parallel pipes to achieve a larger heat exchange surface.

[0026] In an advantageous embodiment, the pipeline, in particular the pipeline bundle, is made of steel, preferably corrosion-resistant stainless steel. Further advantageously, the pipeline, in particular the pipeline bundle, has a corrosion protection layer on its outer surface.

[0027] In principle, a large-surface heat exchanger immersed in seawater can be made of steel. Similar to ships, however, measures to counteract corrosion should preferably be taken, such as cathodic corrosion protection or the use of a sacrificial anode. Simple protective coatings, on the other hand, could reduce the desired heat transfer and are therefore not recommended unless the protective coating is adapted and suitable with regard to its influence on the desired heat transfer. For example, sufficiently thin coatings can be advantageously used to combat so-called fouling, which do not noticeably impede heat transfer. This "fouling" of heat exchangers and heat exchangers, and the resulting cleaning, repeatedly pose a challenge for operation.High-salt water, high temperatures, and contaminants in the water are responsible for the various deposits. These impair both the heating and cooling performance of a heat exchanger. The harder and thicker the deposits become, the worse the heat transfer becomes.

[0028] In a particularly advantageous embodiment, the corrosion protection layer comprises titanium. It can also be made of titanium. In a preferred embodiment, it is also possible to use titanium piping for the large-surface heat exchanger.

[0029] When using titanium as the material for the large-surface heat exchanger, such additional corrosion protection layers or anti-fouling paints can be dispensed with, making this type of design particularly advantageous. Titanium exhibits very good corrosion resistance to seawater. When using titanium tubes, it is preferable to avoid electrical contact with steel components by using suitable insulators to separate the materials. Otherwise, there is the potential for so-called local elements to form, which can cause corrosion phenomena. Local elements are generally small-area corrosion elements (or contact elements) that are barely visible to the naked eye. Local elements can form at the contact points between two dissimilar metals due to the effects of moisture, for example caused by aerosols, and often cause significant corrosion there.

[0030] In an advantageous embodiment, the large-area heat exchanger is arranged in a frame that encloses the heat exchanger and holds the heat exchanger in position for the respective operating state via fastenings.

[0031] Housing and securing the heat exchanger in a frame significantly simplifies its immersion in seawater. It also greatly facilitates its handling and manipulation for different operating conditions. This allows for a modular design with a single module comprising the heat exchanger and frame as a single unit, as well as auxiliary attachments such as connectors or flange connections for the piping for connection to the offshore electrolysis plant's container.

[0032] The submersible heat exchanger is housed in a frame that preferably has the dimensions of a standard logistics container. This makes it particularly easy to transport the heat exchanger and, if necessary, replace it after a certain period of operation, which is advantageous for maintenance and service purposes.

[0033] Preferably, therefore, the frame with the large-area heat exchanger is fixed in such a way that it can be removed or tilted out of the seawater as required.

[0034] Preferably, the frame with the large-area heat exchanger can be tilted out via a rotatable fastening.

[0035] It is particularly practical and advantageous to design the large-area heat exchanger immersed in seawater in such a way that it can be "folded out" or tilted out of the water using simple means, for example, with the help of a cable winch. This can preferably be achieved by a rotatable or rotatable / tiltable fastening device on the frame.

[0036] The ability to fold the large-surface heat exchanger out of the seawater is a particularly advantageous design feature, especially given the offshore requirements of an offshore electrolysis plant. Alternative pipe routings for the heat exchanger are conceivable that do not require the removal of pipe sections to fold out the heat exchanger. For example, the frame can be tilted around the heat exchanger using the rotatable fastening. With a corresponding flange connection for the supply and return lines, which are precisely mounted and aligned on the corresponding rotation axis, only the flange needs to be opened and fitted with blanking plates to fold out the heat exchanger.Within the meaning of the invention, flexible hoses or bellows systems, or combinations of these piping elements, can also be used to connect the container to the electrolyzer, allowing it to be lifted or tipped out without having to loosen, cut, or seal a pipe. Depending on the temperature level of the coolant in the supply and return lines of the coolant circuit, such hoses can also be made of a suitable plastic.

[0037] The offshore electrolysis plant is designed in a particularly advantageous manner with a connection unit for feeding in electrical power from an offshore wind turbine.

[0038] This means that excess electricity from an offshore wind farm can be used directly at sea to produce hydrogen by feeding the electricity via the connection unit of the offshore electrolysis plant.

[0039] This combination of renewable energy and hydrogen production is particularly advantageous for offshore wind farms and other wind turbines located in remote areas. The increased expansion of renewable energy has so far suffered from a lack of grid infrastructure. In Germany, for example, there are no power lines to transport wind power from the sea to the interior and further to southern Germany. An offshore electrolysis plant can help here. With this plant, the electricity generated at sea could be used directly on-site to split seawater.

[0040] In a preferred embodiment, the offshore electrolysis plant according to the invention is therefore installed on an offshore platform in the sea. For example, decommissioned oil or gas platforms, such as those abundant in the North Sea, could serve as the basis for such a wind-powered electrolysis system. The hydrogen produced there could then be conveniently transported to onshore power plants via existing natural gas pipelines.

[0041] In the method for operating an offshore electrolysis plant with an electrolyzer arranged in a container, a coolant is guided in a closed coolant circuit for the heat absorption and dissipation of process heat from the electrolysis from the container, whereby a coolant pump arranged in the container is operated.

[0042] As already explained in the case of the offshore electrolysis plant, a coolant pump arranged in the container is also understood, in principle, to be a fixed coupling by tightly flanging the coolant pump directly to the container from the outside, so that a housing unit of the coolant pump and the container is then formed. Within the scope of the invention, this should be understood to mean that even if the coolant pump is flanged or coupled to the container, the electrolyzer and the coolant pump are housed in the same container, forming a housing unit.

[0043] In a particularly advantageous embodiment of the method, heat is transferred from the coolant heated by the process heat to seawater in the closed coolant circuit, thereby cooling the coolant.

[0044] Preferably, the damaging ingress of seawater into the coolant circuit is monitored. For this purpose, a suitable sensor for detecting leaks in the coolant circuit can be used. Preferably, a measurement of the electrical conductivity is performed using a conductivity sensor that reacts sensitively to seawater-related salinity, so that unwanted ingress of seawater is indicated and appropriate countermeasures can be taken.

[0045] Embodiments of the invention are explained in more detail with reference to the accompanying drawings. These show schematically and in a highly simplified manner: FIG 1 shows an electrolysis plant with air cooling; FIG 2 shows an offshore electrolysis plant using seawater as a coolant in an open coolant circuit; FIG 3 shows an embodiment of an offshore electrolysis plant according to the invention with a closed coolant circuit; FIG 4 shows a further embodiment of an offshore electrolysis plant according to the invention.

[0046] The same reference symbols have the same meaning in the figures.

[0047] In Figure 11a is shown, in which an electrolyzer (not shown in detail), for example a PEM or alkali electrolyzer, is arranged in a container 2 or other housing. The electrolyzer is designed to generate hydrogen as a product from the electrolysis of water as the reactant. For cooling and heat dissipation of the process heat during operation of the electrolyzer, the electrolysis system 1a has an air cooler 6. A coolant circuit 3 ensures the circulation of a coolant, with a medium to be cooled being led to the atmosphere through a heat exchanger 4 with correspondingly large heat exchange surfaces. A coolant pump 5 pumps the coolant. For use of the electrolysis system 1a in the offshore area at sea, this configuration is disadvantageous and is therefore not recommended for offshore applications.Since wind and weather disperse seawater in the form of saline aerosols, the heat exchanger surfaces and the associated external fans of electrolysis plant 1a would be exposed to a highly aggressive environment. High corrosion rates are to be expected here, which would impair the safe operation of electrolysis plant 1a and lead to short downtimes and high maintenance costs in offshore operations.

[0048] In Figure 2An offshore electrolysis plant 1b is shown, in which an electrolyzer (not shown in detail), for example a PEM or alkali electrolyzer, is arranged in a container 2. The offshore electrolysis plant 1b is arranged on a support structure 10, an offshore platform, which is located above sea level 11 and anchored to the seabed. In the container 2, an electrolyzer (not shown in detail), a coolant pump 5 and a heat exchanger (4) are provided. Seawater is used as the coolant and is pumped up from the sea to the heat exchanger 4 by means of the coolant pump 5 for cooling purposes. As a supply for the seawater, an intake nozzle 12 is provided underwater in the suction line leading to the heat exchanger 4, in which the coolant pump 5 is installed. The latter must be designed with appropriate performance due to the height difference. If the coolant pump 5, as in Figure 2shown, are arranged inside the container 2, the vapor pressure of the seawater may even have a limiting effect and cavitation may occur if the height difference is too great. In this case, even the most powerful pumps would not be able to suck in the seawater, which is very detrimental to efficient cooling operation. Alternatively, the pump would have to be placed closer to the water surface, where it may be more exposed to environmental influences and access for maintenance and repair would be more difficult. In order to return the seawater after the heat has been absorbed in the heat exchanger 4, the return line 13 is connected downstream of the heat exchanger (4). The return line 13 dips below sea level 11 and returns the heated seawater.As a result, an open cooling concept has been implemented in the offshore electrolysis plant 1b, which uses seawater as a coolant and is not only disadvantageous from an environmental perspective in the maritime sector, but also with regard to operational safety and downtime, which is explained below using a few selected aspects:

[0049] During operation of the electrolyzer, seawater is sucked in through the intake port 12 located below sea level 11 with the help of the powerful coolant pump 5 and conveyed through the heat exchanger 4. On the opposite side of the heat exchanger 4, the medium of the electrolyzer to be cooled is conducted (in Figure 2not shown), so that the heat is transferred directly to the seawater used as coolant. The heated seawater is returned to the sea via the return line 13 through an outlet opening. This cooling concept has disadvantages. To avoid blockages or defects in the coolant pump 5, it must be ensured that no large foreign objects or even marine life are sucked in. This can be achieved with complex filter systems, but these can become clogged over time and therefore require regular cleaning. This causes significant labor, associated with high maintenance and repair costs, and requires frequent on-site work. Furthermore, even with the finest filters, disruptive "scaling" layers form inside the coolant lines and the heat exchanger 4. These layers can be so-called biofouling, although inorganic layers can also form.Inorganic deposits occur primarily due to the unfavorable temperature dependence of calcite's solubility. Calcite preferentially forms in warmer areas, i.e., inside heat exchanger 4, where such deposits are particularly disruptive and cleaning is difficult or even impossible due to poor accessibility.

[0050] Furthermore, there may be regulations and requirements that prohibit the return of large quantities of heated water to the sea to protect flora and fauna. Such regulations could significantly limit operation, particularly for high-capacity electrolyzers. These problems are overcome in offshore electrolysis plants by the cooling concept of the invention:

[0051] In Figure 3 An offshore electrolysis plant 20 according to the invention is shown. This electrolysis plant 20 overcomes in particular the disadvantages of the above Figure 1 and Figure 2described embodiments. Accordingly, the offshore electrolysis plant 20 shows a container 2 in which an electrolyzer (not shown in detail), for example a PEM or alkali electrolyzer, is arranged. The offshore electrolysis plant 20 is arranged on a support structure 10, an offshore platform, and is designed for offshore use. A coolant pump (5) and a heat exchanger 4, in particular a heat exchanger, are arranged in the container 2. A closed coolant circuit 3 is realized, wherein a large-area heat exchanger 21 can be installed in the coolant circuit 3 in a flow-tight manner via removable pipes 23, so that during operation a coolant can be guided through the coolant pump 5 in a closed coolant circuit 3. The large-area heat exchanger 21 is arranged in a frame 22, fastened, and positioned accordingly ready for operation.The assembly comprising frame 22 and large-area heat exchanger 21 is detachably attached to the support structure 10 by means of fastening elements 24a, 24b. The large-area heat exchanger 21 is submerged below sea level 11. The large-area heat exchanger 21 is arranged in the frame 22 such that the frame 22 encloses the heat exchanger 21 and holds the heat exchanger 21 in position for the respective operating state via the fastenings 24a, 24b. Thus, the operating position of the large-area heat exchanger 21 can be flexibly adjusted, including immersion in seawater or inspection or maintenance positions.

[0052] The seawater provides a particularly efficient heat sink, allowing process heat from the electrolysis to be diverted from the container (2) and transferred to the seawater solely via convection. The closed coolant circuit (3) prevents any damaging mass transfer between the coolant circulating in the circuit and the seawater. These areas are fluidically separated from each other.

[0053] To provide a correspondingly large heat transfer surface and heat transfer efficiency, the heat exchanger 21 has a pipe that is designed with ribs and / or fins on the coolant-carrying pipe outer surface and / or is guided in a plurality of pipe bends. This specific and particularly advantageous embodiment is described in Figure 3 Not illustrated in detail for reasons of clarity. The pipeline is made of steel and has a corrosion protection coating on its outer surface.

[0054] The invention thus provides for the use of seawater as a heat sink in a reservoir of almost unlimited size as a cooling medium, wherein, with a closed coolant circuit (3), only the heat is transferred to the seawater through the heat exchanger (21) immersed in the sea and released to the seawater. This enables high cooling capacities for offshore electrolysis and large heat flows from powerful offshore electrolyzers to be transferred to the seawater via the coolant. The environmental impact of this design is minimal, particularly since a material decoupling of coolant and seawater is provided. In particular, the fact that no seawater is sucked in and instead a closed coolant circuit 3 is present avoids the numerous problems described during operation.No foreign matter can be sucked in, and no undesirable inorganic layers or biofouling can form inside the heat exchanger 21, which increases operational reliability. To enable the heat exchanger 21 to be submerged in seawater, suitable swivel devices and / or lifting tools or cable winches are provided on the offshore electrolysis plant, enabling the heat exchanger 21 to be moved in and out, such as submerging or lifting. This makes it possible to replace or service the heat exchanger 21 as needed after a certain period of operation of the offshore electrolysis plant 20.

[0055] In Figure 4 A further exemplary embodiment of a particularly advantageous configuration of an offshore electrolysis plant 20 according to the invention is shown. Compared to the exemplary embodiment in Figure 3The frame 22 with the heat exchanger 21 is fastened in such a way that, as required, it can be led out, tilted out, or folded out of the seawater. For this purpose, a rotatable fastening 24a of the structural unit, comprising the frame 22 with the large-area heat exchanger 21, to the structure 10 is provided. This advantageous development opens up the possibility of flexibly folding the heat exchanger 21 out of the seawater as required via a rotating mechanism, which considerably facilitates handling. Alternative pipe guides for the heat exchanger are possible, which can be carried out without removing the removable pipe sections 23 - according to the embodiment in Figure 3 - get along.

[0056] The offshore electrolysis plant according to Figure 3 and Figure 4is equipped with a connection unit (not shown in detail) for feeding in electrical power from an offshore wind turbine. An offshore wind turbine can be mounted on the same support structure 10 together with the offshore electrolysis plant 20 comprising the container 2, allowing a direct electrical connection and feeding in electrolysis power generated by the offshore wind turbine.

[0057] During operation of the offshore electrolysis plant 20 for hydrogen production, the electrolyzer arranged in the container 2 is cooled to dissipate the process heat. To absorb and dissipate the process heat from the electrolysis from the container 2, the coolant is conducted in a closed coolant circuit 3, effectively cooling the container 2 and its internal components, in particular the electrolyzer. In the closed coolant circuit 3, heat is transferred from the coolant heated by the process heat from the electrolysis to seawater, thereby cooling the coolant. Damaging penetration of seawater into the coolant circuit 3 or other undesirable leaks in the coolant circuit are monitored.

Claims

1. Offshore electrolysis plant (20) comprising an electrolyser arranged in a container (2) and a heat exchanger (4), which is designed for heat absorption and discharge of process heat from the electrolysis in a closed coolant circuit (3) from the container (2), characterized in that a coolant pump (5) for conveying the coolant in the coolant circuit (3) is arranged in the container (2).

2. Offshore electrolysis plant (20) according to Claim 1, in which a heat exchanger (21), which is immersible in the ocean, is provided in the closed coolant circuit (3) for the heat dissipation of the process heat absorbed by the coolant.

3. Offshore electrolysis plant (20) according to Claim 2, in which to provide a large heat exchanger surface, the heat exchanger (21) has a pipeline, which is embodied having ribs and / or fins on the coolant-guiding pipe outer surface and / or is guided in a large number of pipe curves.

4. Offshore electrolysis plant (20) according to Claim 3, in which the pipeline is made of steel, wherein the pipeline has a corrosion protection layer on the outer surface.

5. Offshore electrolysis plant (20) according to Claim 4, in which the corrosion protection layer comprises titanium.

6. Offshore electrolysis plant (20) according to any one of Claims 2 to 5, wherein the heat exchanger (21) is arranged in a framework (22), which encloses the heat exchanger (21) and holds the heat exchanger (21) in position for the respective operating state via fasteners (24a, 24b).

7. Offshore electrolysis plant (20) according to Claim 6, in which the framework (22) having the heat exchanger (21) is fastened such that if needed guiding or tilting out of the ocean water can be effectuated.

8. Offshore electrolysis plant (20) according to one of Claims 6 or 7, in which the framework (22) having the heat exchanger (21) can be tilted out via a rotatable fastener (24a).

9. Offshore electrolysis plant (20) according to any one of the preceding claims, having a connection unit for feeding electric current from an offshore wind turbine.

10. Method for operating an offshore electrolysis plant (20) having an electrolyser arranged in a container (2), in which coolant is guided out of the container (2) in a closed coolant circuit (3) for the heat absorption and discharge of process heat from the electrolysis, wherein a coolant pump (5) arranged in the container (5) is operated.

11. Method according to Claim 10, in which heat is transferred to ocean water in the closed coolant circuit (3) from the coolant heated by the process heat and the coolant is thus cooled.

12. Method according to one of Claims 10 or 11, in which a damaging penetration of ocean water into the coolant circuit (3) is monitored.

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