Electrochemical cell plant

Abstract

1. A system comprising an electrolyzer stack connected via an inlet pipe and an outlet pipe to a water / gas separation vessel, the separation vessel adapted to passively separate water and gas, the separation vessel housing a heat exchanger, and the separation vessel constructed of a polymeric material.

Description

Technical Field

[0001] The present invention relates to an electrolytic cell system, as well as the separation and cooling of water and gas.

Background Art

[0002] Conventionally, a water electrolysis system releases hydrogen as a beneficial component, oxygen, and heat to the atmosphere. This green hydrogen produced from renewable resources via electrolysis is used in a growing set of applications. Examples of such applications are transportation fuels, long-term energy storage, and renewable chemistry, etc.

[0003] Conventionally, an electrolytic cell stack is connected to a heat exchanger and associated pumps via a plurality of pipes. The heat exchanger / pump is then connected to a gas separation tower. The water and oxygen produced by the electrolytic cell stack are supplied via pipes to separate pumps / heat exchangers to allow cooling, and then the oxygen and hydrogen are supplied to separate gas separation towers. Once cooled, the water is supplied via pipes back to the electrolytic cell stack. Conventionally, these components are positioned separately from each other and are connected by pipes covering long distances. This is due to the preference for using large pumps in the industry (thought to be cheaper / easier). In this system, water is required to be pumped back and forth over long distances, which can lead to pressure losses and has material costs for more piping work. There is also a large balance of the plant in these systems.

[0004] The separate positioning of components and the long distances between components also mean that no test facility is possible at the site where all pumps, heat exchangers, and electrolytic cell stacks are located. This is not optimal since the final system cannot be tested before construction.

[0005] Therefore, conventional electrolytic cell systems possess elements that cannot be manufactured in an efficient factory setting. Instead, they require numerous links to be assembled in the field without prior testing.

[0006] Oxygen and heat are also becoming beneficial by-products of electrolysis (hydrogen is not the only beneficial product). To extract these by-products, components are added to the electrolytic cell system rather than being efficiently integrated. These components are typically metal-based. The conventional manufacturing techniques that are usually relied upon are metal fusion, flange joint assemblies with wrenches, and field pipeline assemblies that give little consideration to the number of components being deployed, which poses considerable manufacturing challenges in modern plant deployment schemes.

[0007] Currently, in the design of electrolytic plants, the field of process engineering involves the placement of separate and general-purpose process equipment comprising an electrolytic cell stack, piping, a heat exchanger (to remove heat from the treated water), more piping, a "knockout" separation tower (to separate water and oxygen gas), numerous flange joints (with nuts, bolts, and tie rods), a pump skid, a glycol tank with pipelines, and associated airflow cooling (adjacent to primary cooling). Furthermore, massive fabrication is required to package these together and link them to large-bore water pipes with trace heating, thermal compensation, and structural support (weight hangers, struts, etc.). These are also complemented by new schemes for oxygen recovery, hydrogen and / or oxygen compression, gas storage, and heat recovery. These components may be located over long distances, contributing to a large footprint, which in itself naturally leads to larger bore pipelines, assembly complexity, and high costs.

[0008] The present invention provides a system including a powerful and cost-effectively manufactured compact oxygen separation vessel. [Overview of the project]

[0009] This invention provides an effective and environmentally sustainable complete water electrolysis system (for cooling water and separating gas from water) that can be fully constructed in a factory setting with repeatable units. It can also be tested in a factory before deployment, which offers numerous advantages, including maintaining a high level of cleanliness. The entire system is located in a single site, with short distances for water and gas to travel. This offers economic and environmental benefits.

[0010] Therefore, according to a first aspect of the present invention, the system comprises an electrolytic cell stack connected to a water / gas separation container via an inlet pipe and an outlet pipe, The separation vessel is adapted to passively separate water and gas. The separation vessel includes a heat exchanger. The separation container is constructed from polymer material.

[0011] According to a second aspect of the present invention, a method for electrolyzing water uses a system as defined above, wherein a gas / water separation vessel contains water, an electrolytic cell electrolyzes the water to produce hydrogen and oxygen, the hydrogen and oxygen then flow through pipes to a separation vessel, and one of the hydrogen and oxygen is passively separated from the water and extracted from the system.

[0012] According to a third aspect of the present invention, an oxygen separation vessel is provided for passively separating water from a mixture of oxygen and water, the vessel comprising: a plurality of inlet nozzles for receiving the mixture of oxygen and water; a heat exchanger positioned within the vessel for cooling the mixture of oxygen and water; at least one oxygen outlet for producing oxygen separated from the mixture of oxygen and water; and at least one water outlet nozzle for outputting water separated from the mixture of oxygen and water.

[0013] The containers of the third embodiment may be used in combination with the systems and methods of the first and second embodiments, respectively. The containers of the third embodiment are preferably for use in combination with an electrolytic cell stack, for example, an electrolytic cell stack for generating hydrogen.

[0014] The third embodiment provides a robust, compact, and cost-effective oxygen separation container.

[0015] Having multiple inlet nozzles leads to the creation of numerous columns of the mixture within the container in use, which significantly improves the oxygen / water separation rate at a given container height, thereby allowing for much shorter containers than conventional oxygen separation containers. For example, the container according to the present invention may be about 2.5 m in height, while conventional containers are generally about three times this height.

[0016] There may be two inlet nozzles, three inlet nozzles, four inlet nozzles, five inlet nozzles, or any other number of inlet nozzles that exceeds one. Preferably, there are three inlet nozzles, which allow three columns of the mixture to be produced.

[0017] Furthermore, having an oxygen separator equipped with a heat exchanger (i.e., heat exchange occurring inside the oxygen separation container) is unconventional and reduces the power required to pump water from the container.

[0018] In conventional systems, the heat exchanger is located downstream of the oxygen separation vessel, and the pump is located between the oxygen separation vessel and the heat exchanger. In this conventional arrangement, the pump is located before the heat exchanger to overcome the pressure drop through the heat exchanger.

[0019] Placing the heat exchanger inside the vessel means that the electrochemically generated oxygen pressure (i.e., generated during electrolysis) leads to an increased pressure inside the vessel, which in turn puts pressure on the free surface of the water within the vessel. This pressure helps overcome the pressure drop caused by the heat exchanger, which means that the pump output can be reduced accordingly.

[0020] This configuration allows for an 18% reduction in pump output, which leads to significant energy savings. Since the power used by the pump during electrolysis is "parasitic" power use, such reductions effectively lower the cost of hydrogen production. This is especially important in low-power scenarios, such as when the electrolytic cell is powered by solar panels on a cloudy day or by a wind turbine on a calm day. In these low-power scenarios, the power required by the pump can represent a significant portion of the total power consumed.

[0021] Preferably, the container (i.e., the body of the container) is constructed from a plastic / polymer material. The container may be constructed from partially crosslinked linear low-density polyethylene "LLDPE" (such as ICORENE (trademark) LLDPE). Alternatively, the container may be constructed from high-performance hexane-high-density polyethylene.

[0022] Preferably, the inlet nozzle is located at or near the top of the oxygen separation vessel. Near the top means that the nozzle is located in the area defined by the top 25% of the vessel in use, and more preferably within the top 10% of the vessel.

[0023] Positioning the inlet nozzle near the top of the container means that the numerous columns of the mixture produced by the inlet container will be larger / higher, thereby allowing for enhanced water / oxygen separation.

[0024] The container may further include at least one through-hole for receiving a lateral cross-member element, and preferably, the at least one through-hole has a substantially rectangular or substantially elliptical cross-section.

[0025] The through-hole may be referred to as a through-opening, a through-passage, or the like.

[0026] The through-hole allows the container to be provided with lateral elements that reinforce / strengthen the container. During use, high pressures are experienced within the container, which could otherwise lead to buckling / failure of the container. Also, the through-hole itself improves the strength of the container by providing a bridge between the side walls, and the through-hole provides vacuum stability against a vacuum that may occur as a result of the negative suction head of the pump (i.e., the through-hole provides a strengthening effect even in the absence of cross-member elements).

[0027] The use of a through-hole having a rectangular or square cross-section is particularly preferred because it promotes the uniformity of the wall thickness of the polymer / plastic liner during manufacture, thereby simplifying the manufacture.

[0028] Preferably, the container further comprises a lateral cross-member element received in the at least one through-hole. Each through-hole may have a lateral cross-member element. The lateral cross-member element is preferably made of steel. The lateral cross-member element may be a tie rod or the like. Alternatively, the cross-member element may be referred to as a reinforcing element or the like.

[0029] Preferably, the container further comprises an external sheet cladding covering at least a part of the outer surface of the container. Preferably, the cladding is made of steel such as a pressure steel plate (e.g., EN10028 P460 pressure steel plate). The cladding may also be provided as a glass fiber reinforcement. The glass fiber reinforcement, also referred to as glass reinforced plastic (GRP), may be used with a linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), polypropylene (PP), or high density polyethylene (HDPE) liner.

[0030] Cladding reinforces the container and increases the pressure it can withstand.

[0031] While cladding and lateral bracing elements alone each provide substantial reinforcement, using them in combination further enhances the reinforcement effect because the bracing elements help distribute the load on the side walls of the container, thereby increasing the load that the container can withstand before it breaks or buckles.

[0032] Alternatively, the container may have at least one circumferential groove for receiving circumferential bracing elements. For example, such circumferential bracing elements may be steel rings or similar that reinforce the container.

[0033] Preferably, the container further comprises two external end plates positioned at opposing ends of the container, the external end plates being joined by one or more longitudinal bracing elements.

[0034] Such end plates and longitudinal bracing elements provide further reinforcement to the vessel. Preferably, the end plates are made from steel such as EN10028 P460 pressure steel, or P350 steel, or 300 series stainless steel of a suitable thickness. The bracing elements are preferably made from steel. The bracing elements may be tie rods or similar.

[0035] Optionally, multiple inlet nozzles and at least one water outlet nozzle may be integrated with the container and constructed from the same material as the container, preferably the nozzles being connected to the pipe by polymer fusion, which is very cost-effective.

[0036] Preferably, the inlet nozzles are positioned at substantially the same height (i.e., when the gas separator is in the orientation in which the gas separator is used). Substantially, this means that the inlet nozzles are at the same height within a 10% deviation of the total height of the container.

[0037] Preferably, the container is rotationally molded in a single, one-shot process.

[0038] Preferably, the container has a flat, elliptical cross-section, with flat side walls positioned vertically during use.

[0039] More preferably, the inlet nozzle is positioned during use such that it directs the fluid flow towards the (preferably flat) side wall of the container, thereby creating a cyclone effect. This improves the efficiency of the water / oxygen separation process and allows the container to be even more compact.

[0040] In other words, the inlet nozzle may be positioned during use to direct the fluid flow along the curvature of one side wall of the container and to the opposing side wall, thereby utilizing centrifugal force to enhance the separation of the fluid and gas mixture.

[0041] Preferably, the container is constructed of high-performance hexane-density polyethylene. High-performance hexane-density polyethylene is clean, highly rigid, and offers high resistance to environmental stress cracking. Alternatively, the container may be constructed of other materials, such as partially crosslinked linear low-density polyethylene.

[0042] Optionally, the vessel may have a tapered collector located between the heat exchanger and at least one water outlet nozzle. This increases the velocity of the fluid flow through the water outlet nozzle.

[0043] Optionally, the heat exchanger may be a tubular heat exchanger.

[0044] Preferably, the oxygen separation vessel further comprises a sleeve arranged around a tubular heat exchanger, and preferably the sleeve is made of a polymer material.

[0045] Preferably, the sleeve comprises an inlet, an outlet, and one or more baffle plates arranged to cause the fluid to flow transversely around the heat exchanger during use. The baffles mean that the interruption of the fluid at the boundary layer between the fluid and the heat exchanger is maximized, thereby improving heat exchange. Transverse flow means that the fluid flows in a direction having a non-zero component perpendicular to the tubular portion of the heat exchanger.

[0046] According to a fourth aspect of the present invention, a system for generating hydrogen is provided, the system comprising an electrolytic cell stack connected to an oxygen separation vessel according to the third aspect.

[0047] Preferably, the system further comprises a pump connected to at least one water outlet nozzle, the pump being located downstream of the oxygen separation vessel. As previously considered, having the pump downstream of the gas separation vessel allows for a reduction in pump power, thereby saving power. The pump drives the flow of water from the oxygen separation vessel. [Brief explanation of the drawing]

[0048] [Figure 1] A schematic diagram of a preferred embodiment of the present invention is shown. [Figure 2] This graph shows that pump power savings in a 2MW system can amount to up to 1.5% of the total power consumption. When the plant is idle with the pumps running, this could potentially save up to 70% of the current plant power. [Figure 3] This is a schematic diagram illustrating the fluid flow in a preferred embodiment of the present invention (only the container is shown). [Figure 4] This is a schematic diagram showing a preferred embodiment of the present invention. [Figures 5a-5c] The first configuration of the container is shown. [Figures 6a-6d] The second configuration of the container is shown. [Figures 7a-7d] The third configuration of the container is shown. [Figures 8a-8d] The fourth configuration of the container is shown.

[0049] Labels in the figure 1. Phase-separated heat exchange O2 pressure one-shot molded vessel (1a, 1b, and 1c represent various configurations of the vessel). 2. Secondary cooling circuit. 3. Pump. 4. Electrolytic stack. 5.Heat exchanger. 6. Molding nozzle (6a is the inlet nozzle / port, 6b is the outlet nozzle / port). 7. Cooling supply. 8. Heat outlet. 9. Water / oxygen mixture. 10. Pressure relief device. 11.Primary cooling circuit. 12. Up to 3 layers of walls. 13. Composite material pressure shell. 14. Antimicrobial additives. 15. The region of turbulence created. 16. H2O collector. 17. Grooves on the container. 18. Refrigerant inlet port. 19. Refrigerant outlet port. 20. Internal conduit. 21. Through hole. 22. Oxygen outlet. 23. External cladding. 24. Lateral tightness. 25. End plate. 26. Longitudinal tie rod.

[0050] Description of Preferred Embodiments As used herein, electrolytic cell stack and water / gas separation vessel (or tower) are terms used in the art. A stack comprises multiple electrolytic cell units.

[0051] As used herein, heat exchanger is a term known in the art. In the context of an electrolytic cell, an electrolytic cell cools water that flows through an electrolytic cell system.

[0052] The inventors have devised an electrolytic cell system comprising a multi-purpose container that combines large-scale purified water storage, separation of oxygen and / or hydrogen from water, heat exchange, and optionally, manufacturing-free porting (i.e., avoiding the need for manufacturing and additional processes on additional ports), and improved purity in a single module.

[0053] The advantage of the present invention is that, in contrast to the prior art which requires electrolytic cells to be assembled in the field with pipes, separation towers, and pumps and then tested, it allows for a large number of self-sufficient electrolytic modules, i.e., repeatable and manageable units.

[0054] The oxygen separation container of the present invention is also smaller than conventional separation containers, thereby making transportation and installation easier and allowing it to be installed in a smaller space.

[0055] The core of this invention involves a twofold modification to existing systems. Firstly, locating the heat exchanger inside the gas separation tower reduces plant balance and improves efficiency. Secondly, the integrated heat exchanger and gas separation unit can be coupled to the electrolytic cell over a short distance (due to component compatibility), which improves system efficiency. Previously, due to the large plant balance, the electrolytic cell stack had to be connected to the large water / gas separation tower and individual heat exchangers over a much longer distance. This made field assembly and testing extremely difficult.

[0056] The gas separation vessel is constructed from a polymer material. Preferably, the gas separation vessel is constructed from a plastic material.

[0057] The gas separation vessel may be constructed of partially crosslinked linear low-density polyethylene "LLDPE" (such as ICORENE® LLDPE) or high-performance hexane-high-density polyethylene. Alternatively, the gas separation vessel may have a multi-walled structure with pressure steel plates as the outer liner or cladding (such as EN 10028 P460 or P350 steel or 300 series stainless steel of a suitable thickness). Alternatively, the outer liner or cladding may be glass fiber reinforced.

[0058] The separation vessel preferably includes multiple nozzles for connecting to inlet and outlet pipes, the pipes being integral with the vessel and constructed from the same polymer material as the vessel. This offers several manufacturing advantages.

[0059] In a preferred embodiment, the container comprises at least four nozzles, at least two of which are fitted to communicate with fluids in each pipe.

[0060] More preferably, the system comprises at least six nozzles, with at least three nozzles adapted to communicate with fluids in each pipe.

[0061] Preferably, the container (preferably including a nozzle) is injection molded or rotationally molded in a single, one-shot process from a polymer material. More preferably, the pipe is also constructed from a polymer material. This is advantageous because various components can be connected by polymer fusion. This avoids the need for complex metalwork and flanges as in the prior art.

[0062] The reduced number of parts in the system of the present invention leads to design efficiency and ease of deployment, which can be achieved in the proposed invention by rotational molding technology that generates up to 15 ports / nozzles directly into the container wall itself. The aforementioned nozzles can then be directly connected to the piping via automated polymer fusion welding, which eliminates the need for conventional fusion fittings, flanges, wrenches, gaskets, nuts, bolts, and washers, and also ensures leak-proof airtightness.

[0063] The placement of conventional, separated accessories (towers and associated equipment) away from the hydrogen production (stack) involves calculations of many parts (due to the large bore, force, and weight involved) and leads to difficulties in controlling flow and cleanliness. For example, this involves lifting heavy objects at the assembly site, and the ends of pipes may be open to elements at the construction site.

[0064] The system of the present invention is shown in Figure 1. In the system of the present invention, water from the electrolytic cell stack is supplied into an integrated gas separation and heat exchanger unit. In this integrated unit, the heat exchanger is submerged in the water flowing into the gas separation tower during use, and plays a role in cooling the surrounding water. This cooled water is then supplied back to the electrolytic cell.

[0065] In a preferred embodiment, the electrolytic cell stack is connected to the separation container over a short distance, and as a result, can be located within the same building, preferably in close proximity to each other. Reducing the distance between the electrolytic cell stack and the heat exchanger and gas separation unit integrated therein avoids various drawbacks of the prior art, such as the economic impact associated with transporting and pumping water over long distances.

[0066] This invention integrates the auxiliary functions of electrolysis into a least common denominator (module) by using design and assembly rules associated with lean assembly (fewer parts and a rational interface), establishing all manufacturing and testing in the factory under controlled conditions. Forming the product into such an architecture benefits the organization in several ways: firstly, it standardizes the auxiliary functions with an emphasis on interchangeability; secondly, it reduces parts inventory and improves quality (e.g., the number of parts in one pump); and thirdly, it shortens inventory (and all management tasks), manufacturing cycle time, and also minimizes field installation time. This invention allows for the use of "snap-and-go" piping because the pipes are constructed from polymer material. The system can then be connected via integrated nozzles, and pipes with small bore diameters of less than 50 mm can be used, reducing the burden on workers and decreasing the need for heavy machinery, and currently this task is best described as a simple piping task. This is in stark contrast to the use of 350 mm bore in the prior art, which is best described as a heavy industry task. Because this invention can be assembled in a factory setting, it reduces the burden on installation space, pump losses, and contamination.

[0067] The present invention is preferably manufactured by a one-shot injection molding method, which has the advantage of being easy to manufacture. The present invention is also preferably formed by rotational molding, which allows for rapid manufacturing.

[0068] In preferred embodiments, the container is insulated to allow preheating, installation of convenient instruments (measurement of water conductivity, level, and temperature), and prevention of microbial growth. In preferred embodiments, the polymer container of the present invention contains an antimicrobial or antifungal agent. Such agents are known in the art. The agent may be provided to a preferably single-piece-free, recyclable thermoplastic mold by including an additive in the molding process.

[0069] The vessel of the present invention allows for complete factory assembly, integration, and testing, and its tight integration with the stack avoids the need for flange and porting fabrication, while requiring smaller bores, shorter piping lengths, and less head loss. This results in savings in assembly time, reduced potential for leaks, reduced head pressure, and improved flow control. This is because the elements of the system are no longer separated from the electrolytic cell stack and from each other.

[0070] This invention reduces the number of parts and complexity, and the use of pumping energy. Significant pump power savings are achieved through several factors. Typical embodiments of this invention reduce losses through the arrangement of heat exchangers (see Figure 2), shorter duct lengths (a beneficial aspect of which is reduced friction losses), and the ability to use multi-stage pumps, which allows for a greater degree of energy saving adjustment than is possible with other methods that do not use this invention.

[0071] In a preferred embodiment, the container has a flat elliptical cross-section with flat side walls positioned vertically during use. This embodiment is shown in Figure 3. Preferably, the nozzle is positioned during use such that it directs the fluid flow to the (preferably flat) side walls of the container, resulting in the creation of a cyclone or centrifugal force effect. The nozzle directs the fluid flow along the curvature of one side wall of the container and toward the opposing side wall. This is also shown in Figure 3. Preferably, the fluid flow is directed at an angle of about 45 degrees to the side walls so that a region of turbulence or a cyclone is created. This allows for efficient water / gas separation. The angle of the nozzle (i.e., the inlet nozzle) may be 30 to 60 degrees, more preferably 35 to 55 degrees, even more preferably 40 to 50 degrees, and most preferably about 45 degrees (i.e., 44 to 46 degrees).

[0072] The wire brush may be positioned within at least one nozzle so that the kinetic energy of the fluid flow is interrupted during use.

[0073] In a preferred embodiment, a vortex breaker, vortex spoiler, or demister pad is located inside at least one of the pipes.

[0074] In a preferred embodiment, the container ratio is such that the ratio of the container's height to its width is less than 3:1 or 2:1, or preferably about 1:1. While we do not wish to be constrained by theory, this may be possible for nozzles that direct the fluid flow toward the sidewalls so that a cyclone / centrifugal effect is created. This allows for more effective water / gas separation and means that the separation container does not need to be as tall as conventional separation containers.

[0075] Conventional vessels have a height-to-width ratio that is mostly vertical, approximately 6:1, to accurately separate gas and water. This is to prevent the mixture of water and gas from re-flowing into the pump inlet. Polymer-based and fusion-welded vessels with a 6:1 ratio are ergonomically and manufacturably difficult to handle. Polymer-based and fusion-welded vessels with a 6:1 ratio are brittle and prone to breakage, inevitably leading to other costly and necessary precautions. In a preferred embodiment of the present invention, the ease of manufacturing the vessel itself, with its split ports (multiple nozzles) and 1:1 ratio, is achieved by a rotational molding process, and the cleanliness of the process side is achieved by joining flanges, or by manually drilling or deburring the plastic (these features are essential for molding in a "one-shot" process), ensuring that no burrs are created.

[0076] The gas separation "knockout" tower used in conventional systems is 1m in diameter and 6m in height (total 4.8m). 3 The columns are 2.6m × 2.6m × 1m (total 6.8m), which makes handling and manufacturing in a well-equipped factory impractical and difficult to export (via road or sea freight) or assemble on-site. This reduces the range for effective deployment of a series of units. In contrast, the typical aspect ratio of a typical embodiment of the proposed invention is 2.6m × 2.6m × 1m (total 6.8m).3 It is a rectangular prism and a much more practical load for effective handling.

[0077] Conventional techniques involve joining many flanges one by one and bolting them to the tower on-site (because the finished assembly is too large to transport in some cases), and include inefficient practices and tools, which are at least prone to more leaks that need to be corrected on-site from the start.

[0078] The heat exchanger used in this invention is preferably a tubular heat exchanger. This heat exchanger has a supply of coolant, preferably chilled water flowing through the inside of its tubular structure, which then cools the outer surface of the metal, and then this chilled metal exterior cools the surrounding water in the gas separation tower supplied from the electrolytic cell stack. The process fluid is drawn in from the shell side to the pump inlet, while the tubular side of the heat exchanger is connected to the refrigerant circuit. In current state-of-the-art technology, the heat exchanger is located downstream of the pump. In this invention, the heat exchanger is located upstream of the process pump. In this invention, the pressure drop through the heat exchanger is overcome by the electrochemically generated oxygen pressure, particularly the absolute pressure applied to the free liquid surface in the suction vessel. Therefore, the pump output can be reduced accordingly. A pressure drop reduction of 0.6 to 1 bar g leads to a reduction of about 10 to 16% in pump output. (In such a system, the overall pressure drop is about 6 bar).

[0079] The present invention significantly reduces the footprint and number of parts, and improves manufacturing capacity through a nozzle without numerous joints. The present invention allows for a variety of coolant types through a specific selection of heat exchanger types (enabling diverse downstream integration possibilities) and the virtual elimination of pump head losses from the primary cooling side to avoid pump "parasitic losses" in reduced regimes, while oxygen pressure capacity and "integrated antimicrobial measures" also ensure maximum cleanliness during idle time.

[0080] In a preferred embodiment, the heat exchanger, preferably a tubular heat exchanger, is located in the highest flow region of the vessel, thereby avoiding considerable resistance to flow on the "shell" side of the vessel compared to a conventional plate heat exchanger. This reduces pump losses compared to a conventional plate heat exchanger (which is made from numerous narrow, fluid-colliding openings). Head pressure savings are assessed using the law of pump affinity, which manages centrifugal pump-based water circulation and derives a minimum pump energy saving of 14%, a figure achieved through pressure head reduction by a floating tubular heat exchanger alone. In addition, compared to a plate heat exchanger which typically includes multiple plates, seals, end plates, studs, washers, and nuts, a tubular heat exchanger is made from a single fabricated part.

[0081] The robustness and versatility of the selected type of heat exchanger can be described in terms of "fouling" in addition to chemical lifespan, chemical salt resistance, resistance to debris, and low pressure loss. The colder flow is on the tube side (the colder flow flows internally on the tube side). This is unusual and actually reduces the heat exchange coefficient (the ability to release heat), and conventionally this is not adopted. However, the reduction in the heat exchange coefficient is very modest and does not constitute a major compromise. The other advantages, such as the larger pump and flow rate on the electrolytic side, more than compensate for this, and this more than balances out this negative aspect. This arrangement allows a wide range of coolant types that cannot be accommodated on the shell side to be used on the tube side (internal), resulting in a significant reduction in the amount of equipment on the secondary cooling side.

[0082] The system of the present invention opens up the possibility of using natural water channels or seawater as a coolant in electrolytic processes. In heating large-scale swimming facilities, districts, or industrial spaces, the heat exchanger is resistant to chlorinated water or inhibitors, and heat can be recovered, increasing overall efficiency toward a fully passive system standard. Tests have shown that energy efficiencies exceeding 95% can be achieved in some cases. The main advantage of the present invention is the permissible coolant type and specification, which can be any fluid that is roughly filtered and provided at temperatures in the range of above freezing ~40°C. Coolants such as seawater or water from channels, which are not normally conceivable, become possible with the present invention. This takes precedence over concerns of heat exchange performance, privileged system integration, and small footprint. Cooling primary treated water is particularly attractive in offshore applications such as offshore wind turbines, though not limited to offshore wind turbines, allowing for significant reductions in footprint and paving the way for future wind turbine integration. The size of the stack module associated with the module can be selected very carefully to match the "Type IV" DC link voltage of 690V (suitable for electrolysis) of the wind turbine. Thus, the system of the present invention can be adjusted to have 300-350 electrochemical cells as standard. It is important to match the DC voltage of the electron donor (wind turbine) to the load voltage (electrolytic cell). The present invention can define a container volume that matches the stack that the container will receive.

[0083] In this invention, the required length of ducts or pipes is shortened due to the juxtaposition and merging of accessories. This results in a considerable amount of parts and space savings (pipe length is obvious, but elbows, unions, flanges, shut-off valves, strainers, filters, metal bellows, pipe hangers, anchors, lugs, heat traces all add more head loss, etc.) and leads to a minimum pump power reduction of 1% (this is a conservative estimate as it only considers the reduction in pipe length). A reduction of 0.6–1 bar over 6 bar (common in PEM electrolytic cell stacks) and the repositioning of heat exchangers to utilize the head of pressure generated above the liquid surface in the tank reduces pump power by 10–16%. The ideal situation is to achieve the largest possible bore with the shortest possible length. This points the way to truly optimized development in terms of head loss and parasitic head loss. This approach is unnatural to many engineers, whose natural tendency is to add rather than reduce parts.

[0084] In preferred embodiments, a centrifugal pump, preferably a multistage centrifugal pump, is used in the present invention. Specifically, a preferred location for the pump, which is within the piping leading from the separation vessel to the electrolytic cell stack, is shown in Figure 1. Multistage centrifugal pumps are preferred to the present invention because they offer a greater potential for "turndown" than single impeller pumps and provide the best synergistic effect for power savings. "Turndown" is typically thought of when hydrogen demand is low and the need for primary coolant flow is reduced. With partial or reduced hydrogen demand, less fluid needs to be pumped around the system, which is referred to as "turndown." The general idea is that turning down the pump speed reduces power consumption, which is highly beneficial as pump applications consume 20% of the world's electricity and green systems should be exemplary in energy saving. Turndown is even more important for electrolysis systems that are widely deployed using very large pumps, such as the system of the present invention. Turndown also significantly reduces the client's operating costs and provides a competitive advantage.

[0085] In a preferred embodiment, the pump is capable of achieving a lower shaft speed for the same output flow rate. This is referred to as turndown capability, and in other words, the pump of the present invention preferably has good turndown capability. When properly planned, turndown is expected to save up to 40% of the pump's energy consumption.

[0086] Multistage centrifugal pumps allow for greater turndown when controlling the pump using speed, and as stated by the law of affinity, the greater the speed reduction, the greater the reduction in kilowatt-hours used. The synergistic effect of pump selection with the present invention is that the head pressure can be reduced, and as a result the number of stages in the pump can be optimized (from 6 to 3 stages, see Figure 2), as well as benefiting from the turndown capability (generally 37% for multistage pumps compared to 5% for single-impeller pumps), which is argued to reduce the power used beyond standards that are similarly achievable with multistage or single-impeller pumps, and thus constitute the advantage of this feature.

[0087] In the field of two-phase gas-liquid separation, there are various separation techniques. As previously referenced, the vertical knockout tower is the simplest and most common state-of-the-art form, but it suffers from the slowest separation and the largest footprint of all. This is because it relies on the residence time of the gas-water mixture (and to accommodate this, the minimum column height required) as well as gravity, allowing the water to "fall" towards the top of the container at the collector outlet and the gas bubbles to "rise."

[0088] Figure 1 shows three nozzles connected to each pipe. Thus, this preferred embodiment divides the flow and height by the maximum possible 3, leading to the selection of the typical height of 2.6 m described above. This leads to more efficient separation.

[0089] In one embodiment, the present invention includes a Schoepentoeter device that divides a mixed-phase feed stream into a series of lateral and curved flows. These curved flows dissipate the kinetic energy of the flow for smooth entry into the container and also provide centrifugal acceleration to facilitate the separation of liquid from gas.

[0090] In some embodiments, a tangential cyclone is created within the separation vessel. This relies on centrifugal acceleration to separate the gas and water. Figure 3 shows how this can be achieved, namely by angling and directing the fluid flow toward the side walls of the separation vessel.

[0091] In a preferred embodiment, the nozzle is provided tangentially or near tangentially to create centrifugal acceleration (this mechanism enhances separation efficiency). This is schematically shown in Figure 3. The nozzle directs the flow toward the vessel wall, and as the flow hits the bottom, it wraps around or swirls around the heat exchanger as the curvature of the vessel decreases, mimicking the effect of baffles placed around conventional cooling heat exchangers. Swirling and turbulence around tubular heat exchangers are beneficial.

[0092] The container of this invention potentially has a large number of nozzles. However, this does not add complexity because the nozzles are molded as part of the rotationally molded container itself.

[0093] In preferred embodiments, the present invention includes the use of a demister pad consisting of a fine mesh or mesh grid to further remove mist from the vapor after the separation has been affected. Additional features also include vortex breakers and vortex spoilers.

[0094] In one embodiment, the kinetic energy of the flow is interrupted by a set wire brush arrangement coaxially located with the inlet nozzle. These types of brushes are known to be cost-effective in small air-gas separators.

[0095] In preferred embodiments, the container walls may include foam insulation (to reduce radiant heat when off), as well as a three-wall structure consisting of polypropylene, foam, and polypropylene. Further lightness, ease of handling, cleanliness, antimicrobial resistance, and deployability in specific environments of varying sizes (such as containerized packages or within single-story buildings, facilitated by appropriate aspect ratios) are defining utility features, and all market segments can be accommodated as numerous modules are efficiently fitted together by small-bore pipes. Reducing the number of parts is significant. A single container is designed for the most demanding applications. This module can be manufactured in a factory many times faster than current technology (reducing the time from four days to a few hours for comparable container manufacturing), and avoids the lengthy deburring phase (reduced from two weeks to zero). Current alkaline units of the prior art inherit heavy industry methods, component-intensive designs, corrosive systems, and outdated chemistry. For example, designs such as the conversion of chloroalkali to water electrolysis, while successfully attempted by many competitors, are outdated in that they were hardly considered when the lean manufacturing method was conceived, a characteristic unique to the chemical / process industry, highly self-limiting, and very frequently overlooked. Outdated plants are simply rearranged and reused, maintaining the previous physical embodiment by merely adapting the chemical properties or coatings of the electrodes, with the rest added in a logical but makeshift manner. The production volume of fusion welds, the weight of the steel structures used are simply astonishing, and in some cases, in line with existing practices, the height is up to three stories, 7m compared to 2.6m. The suitability of outdated plants for their intended purpose is questionable, and when faced with the task of deploying hydrogen on a large scale in a rapidly changing world, outdated plants seem like mere distractions.

[0096] The energy cost of oxygen-air separation is 6.6 kWh / kg. Oxygen is not typically collected as a byproduct of hydrogen production. Therefore, a net economic benefit can be achieved if pressurized. Decarburization in the steel industry, oxygen combustion, and even fish farms are just a few of the possible applications. For pressure retention, in some embodiments, the vessel has a composite external structure covering a polymer wall obtained by rotational molding. Therefore, in some embodiments, a metal, preferably aluminum, sheath is wrapped around the vessel of the present invention and riveted. Preferably, at least two structural members are arranged longitudinally and vertically to reinforce and mitigate the inevitable creep of the polymer vessel under pressure.

[0097] In some embodiments, the vessel of the present invention includes ports for sensor level control (e.g., three ports), a port for sensor pressure control (e.g., one port), a port for conductivity control (e.g., one port), ports for deionized water circulation (e.g., inlet and outlet, two ports), a port for oxygen ventilation (e.g., one port), a port for oxygen pressure relief (e.g., one port), ports for heat exchanger (e.g., inlet and outlet, two ports), a port for pump outlet (e.g., one port), return ports for the mixed phase port (three in a typical embodiment), and discharge ports (e.g., two ports). A total of up to 17 ports are provided, constituting savings over the prior art.

[0098] Preferably, the container for use in the present invention includes a tapered collector positioned beneath the heat exchanger. The container is preferably directly connected to the heat exchanger. The container is preferably constructed from a polymer material. Figure 4 illustrates a tapered collector. Item 13 is a tapered collector (preferably polymer-processed) that fits snugly beneath the heat exchanger and is connected to the inlet of the main pump to increase the velocity of water passing through the heat exchanger. Pump (3) is connected to the pump outlet of the container and has suction force, which drags the flow vigorously through the heat exchanger to maximize the cooling capacity.

[0099] The uniformity of the crossflow velocity through the heat exchanger is controlled by the provided tippings, which mitigate the velocity near the pump outlet port and increase the velocity further away from the outlet (towards the obtuse angle) (effectively reducing the longitudinal variation of the crossflow), and are arranged to obtain less longitudinal velocity variation.

[0100] Alternatively, the container for use in the present invention includes a sleeve positioned around the heat exchanger. The sleeve is made of a polymer material. The sleeve includes baffle plates arranged such that the fluid direction is "cross-flow" around the tube, maximizing boundary layer disruption between the tube and the fluid to maximize heat exchange. The baffles, tube gaps, and tube lengths are adapted to design the pressure loss characteristics of the heat exchanger according to Figure 8b.

[0101] Figures 5a to 5c show the first configuration of the oxygen separation container 1a. Figure 5a shows a side view of the container 1a, Figure 5b shows an end view of the container 1a, and Figure 5c shows a cross-sectional view of the container 1a passing through the cross-sectional line CC.

[0102] The illustrated container 1a has three inlet nozzles 6a, five outlet nozzles 6b, a series of circumferentially parallel grooves 17, a coolant inlet port 18, and a coolant outlet port 19.

[0103] The groove 17 is shaped to receive a bracing element, such as a metal reinforcing ring. Such a bracing element provides additional strength to the container 1a, thereby reducing the risk of buckling of the container 1a due to the high pressure applied inside the container 1a during use.

[0104] As illustrated in Figures 5b and 5c, the inlet nozzle 6a is positioned during use at an angle (approximately 45 degrees in the illustrated example) that directs the fluid flow toward the (flat) side wall of the container, thereby creating a cyclone / centrifugal effect (as described above).

[0105] As illustrated in Figure 5c, the internal conduit 20 is formed between the coolant inlet port 18 and the coolant outlet port 19. This internal conduit may have additional channels that allow the flow of coolant through the container 1a and also allow the flow of other fluids, such as water separated from the water / oxygen mixture (the additional channels may be coupled to one or more outlet nozzles 6b). The internal conduit 20 may also have additional components, not illustrated, that act (or house) as a heat exchanger and enable it to function as or house such a heat exchanger (such as the heat exchanger in Figure 8b).

[0106] The second configuration of container 1b is shown in Figures 6a to 6d. Figure 6a shows a graph projection of container 1b, Figure 6b shows a side view of container 1b, Figure 6c shows a bottom view of container 1b, and Figure 6d shows an end view of container 1b.

[0107] Container 1b has three inlet nozzles 6a, five outlet nozzles 6b, two oxygen outlets 22 located at the top of container 1a, a coolant inlet 18, and a coolant outlet 19. Unlike container 1a in Figures 5a-c, container 1b in Figures 6a-d does not have grooves, but instead has a plurality of lateral through-holes 21 between the side walls of container 1b. The illustrated holes 21 have a (substantially) circular cross-section. The exemplary container 1b has nine holes arranged at regular intervals, but alternative numbers of holes, such as four, six, or eight, may be used.

[0108] Each hole 21 is positioned to receive a bracing element, such as a tie rod or similar, capable of maintaining tension. During use, the bracing element reinforces the container 1b against high internal pressure, thereby preventing the container 1b from buckling or otherwise breaking / deforming. Using through holes instead of grooves (as shown in Figures 5a-c) means that the side walls of the container 1b can be manufactured smoothly while maintaining the strength and integrity of the container 1b. Since having smooth side walls is easier to manufacture than having grooved side walls, the use of through holes 21 allows for easier and cheaper manufacturing than grooved containers.

[0109] Figures 7a to 7d show alternative containers 1c. The figures in Figures 7a to 7d correspond to the figures in Figures 6a to 6d, respectively.

[0110] Container 1c is similar to the containers in Figures 6a-d, except that the nine circular through-holes are replaced by six through-holes 21 having a substantially square cross-section. It should be understood that the through-holes may have other cross-sections, such as (substantially) elliptical or (substantially) rectangular, and may be selected depending on the tooling requirements during manufacturing and / or the type of bracing element used. Similarly, there may be more or fewer through-holes. In any case, the through-holes 21 are preferably arranged regularly to ensure uniform distribution of load by the lateral bracing element.

[0111] Figures 8a to 8d show container 1b of Figures 6a to 6d with reinforcing elements. The figures in Figures 8a to 8d correspond to the figures in Figures 6a to 6d, respectively.

[0112] The container 1b is preferably provided with an external sheet cladding 23 which is steel such as EN 10028 P460 pressure steel or equivalent. The cladding 23 reinforces the container 1b and thereby helps maintain the integrity of the container during use and reduce the risk of buckling or the like.

[0113] The container also includes lateral bracing elements 24 received within the through-holes 21 in the form of lateral tie rods. These bracing elements 24 are preferably made of steel, and alternative lateral bracing elements may be used instead of tie rods.

[0114] While the cladding 23 and the lateral bracing elements 24 each provide substantial reinforcement individually, using them in combination further enhances the reinforcement effect by helping to distribute the load applied by the bracing elements 24 to the side walls of the container 1b, thereby increasing the load that the container 1b can withstand before it breaks or buckles.

[0115] In addition to the cladding 23, the container 1b is provided with two end plates 25, each positioned at an opposing end of the container 1b. The end plates 25 are connected by longitudinal bracing elements 26, which may also be tie rods or similar, and are preferably made of steel. The longitudinal bracing elements 26 extend between the end plates 25 and are joined to one of the end plates 25 at each end. In this way, the end plates 25 combined with the longitudinal bracing elements 26 provide reinforcement to the container 1b, preventing the container from buckling or breaking due to the high internal pressures experienced during use. Preferably, there are four longitudinal bracing elements 26, for example, by joining each corner section of one end plate 25 to the corresponding corner section of the opposing end plate 25.

[0116] The end plate 25 is preferably made of steel such as EN10028 P460 pressure steel or equivalent.

[0117] The cladding 23, bracing elements 24, 26, and end plates 25 are described in relation to the container 1b illustrated in Figures 6a-d, but they may be used with other containers as shown in Figures 7a-d. The use of the lateral tie rods 24 requires the container to have through holes 21, but the cladding and end plates may be used with containers that do not have through holes.

[0118] Alternatively, the rolled aluminum or steel shell foam can be replaced with a glass fiber semi-cylindrical shell foam (to accommodate the lightweight and tensile stress of the circular portion of the container), while the side walls (subject to bending stress) can be made from ductile steel or aluminum.

[0119] Figures 5a-c, 6a-d, 7a-d, and 8a-d are technical drawings showing the container to scale; i.e., the proportions in the drawings are accurate. The dimensions shown in these figures are given in millimeters (mm). While the dimensions illustrated in these figures are preferred values, they should not be construed as limiting unless otherwise stated in the claims.

[0120] It should be understood that the number of inlet nozzles 6a in any of the above examples can be varied. The example has three nozzles, but alternatively there may be one, two, or four or more nozzles. However, it is preferable to have more than one inlet nozzle because this leads to the creation of numerous columns of the mixture in the container, which greatly increases the separation rate at a given container height, thereby allowing the container to be much shorter than a conventional oxygen separation container.

[0121] Not all of the exemplary vessels are illustrated with oxygen outlets 22, which are omitted for the sake of simplicity in the drawings, and it should be understood that each vessel is intended to have at least one oxygen outlet.

[0122] Any of the containers shown in Figures 5a-c, 6a-d, 7a-d, and 8a-d can be used in combination with the system described above, referring to Figures 1-4.

[0123] The container may be referred to, in other words, as a gas separation container or an oxygen separation container. A preferred embodiment of the container is as an oxygen separation container for separating oxygen from a mixture containing oxygen and water (particularly in the context of green hydrogen production from renewable energy), but it can also separate other gases from other mixtures. Generally, because mixtures of oxygen and hydrogen are unstable / volatile, oxygen and water are separated at various stages.

Claims

1. A system in which an electrolytic cell stack and a water / gas separation vessel are connected via an inlet pipe and an outlet pipe, The separation container has a flat first side wall and a flat second side wall, which are arranged vertically and facing each other during use, The first side wall and the second side wall are connected to the upper and lower curved walls, It further comprises a third side wall and a fourth side wall arranged opposite to each other, The third and fourth side walls are continuous with the first side wall, the second side wall, the upper curved wall, and the lower curved wall, respectively, and are integrally molded to form a sealed space within the separation container. Multiple inlet nozzles for receiving a mixture of water and gas are provided on the upper part or near the upper part of the first side wall of the separation container, At least one outlet nozzle for producing water separated from a mixture of gas and water, located at or near the bottom of the separation container, The separation container comprises a heat exchanger located in or near the bottom of the container for cooling the mixture of gas and water, The separation container has an elliptical cross-sectional shape with a flat portion, obtained perpendicular to the first side surface. The separation container and the electrolytic cell stack are connected to each other via fluid communication through an inlet pipe via the plurality of inlet nozzles and an outlet pipe via the outlet nozzles. The separation container is adapted to passively separate the gas and water by utilizing the cyclone effect generated by the fluid inside the separation container during use. The separation container is constructed of polymer material, The plurality of inlet nozzles are positioned such that their openings are inclined at an angle of 30 to 60 degrees clockwise with respect to the flat portion in a cross-sectional view of the first side wall of the separation container, and during use, the plurality of inlet nozzles are positioned to direct the fluid flow along the curvature of the upper or lower curved wall of the separation container and toward the opposing second side wall, thereby creating a cyclone effect. The third side wall has a coolant inlet port, and the fourth side wall has a coolant outlet port. The coolant inlet port and coolant outlet port are connected via an internal conduit. The system wherein the internal conduit allows the flow of coolant through the separation container and functions as a heat exchanger or houses a heat exchanger.

2. The system according to claim 1, wherein the separation container further comprises a plurality of outlet nozzles for connecting each of the outlet pipes, and the inlet nozzles and outlet nozzles are integral with the separation container and are constructed of the same polymer material as the separation container.

3. The system according to claim 2, wherein the separation container comprises at least four nozzles, at least two inlet nozzles fitted to fluidly communicate with the inlet pipe, and at least two outlet nozzles fitted to fluidly communicate with the outlet pipe.

4. The system according to claim 2 or 3, comprising at least six nozzles, wherein at least three inlet nozzles are adapted to communicate fluidly with the inlet pipe, and at least three outlet nozzles are adapted to communicate fluidly with the outlet pipe.

5. The separation container is rotationally molded from the polymer material in a single one-shot process, according to any one of claims 1 to 4.

6. The system according to any one of claims 1 to 5, wherein the inlet pipe and outlet pipe are constructed from a polymer material.

7. The system according to any one of claims 1 to 6, wherein the inlet nozzle is connected to the inlet pipe and the outlet nozzle is connected to the outlet pipe by polymer fusion.

8. The system according to any one of claims 1 to 7, wherein a vortex breaker, vortex spoiler, or demister pad is located in at least one of the inlet or outlet pipes.

9. The separation container comprises an antibacterial or antifungal additive, according to any one of claims 1 to 8.

10. The system according to any one of claims 1 to 9, wherein the heat exchanger is a tubular heat exchanger.

11. The system according to any one of claims 1 to 10, wherein the heat exchanger is adapted to use water, for example, seawater, as a coolant.

12. The system according to any one of claims 1 to 11, wherein at least one pipe includes a pump for enabling the flow of fluid around the system during use, the pump being located within the pipe that flows from the separation container to the electrolytic cell stack.

13. The system according to claim 12, wherein the pump is a centrifugal pump.

14. The system according to any one of claims 1 to 13, wherein the separation vessel includes ports for sensor level control, sensor pressure control, conductivity control, deionized water circulation, oxygen pressure release, or connection to and from the heat exchanger.

15. The system according to any one of claims 1 to 14, wherein a tapered collector is located between the heat exchanger and the outlet pipe, and the velocity of the fluid flow to the outlet pipe is increased during use.

16. The system according to any one of claims 1 to 15, wherein the coolant inlet port is located below or near the third side wall, and the coolant outlet port is located below or near the fourth side wall.

17. A method for electrolyzing water using a system according to any one of claims 1 to 16, wherein the water / gas separation vessel contains water, the electrolytic cell stack electrolyzes the water to produce hydrogen and oxygen, the hydrogen and oxygen then flow through pipes to the separation vessel, and one or both of the hydrogen and oxygen are passively separated from the water by utilizing the cyclone effect of the fluid generated in the separation vessel during use and extracted from the system.

18. An oxygen separation vessel for passively separating water from a mixture of oxygen and water by utilizing the cyclone effect generated by the fluid in the separation vessel during use, wherein the oxygen separation vessel is It has an elliptical cross-section with a flat section, A first side wall and a second side wall are flat and perpendicular to the mounting surface, and are positioned opposite each other. The first and second side walls are connected to the upper and lower curved walls, respectively. It further comprises a third side wall and a fourth side wall arranged opposite to each other, The third and fourth side walls are continuous with the first side wall, the second side wall, the upper curved wall, and the lower curved wall, respectively, and are integrally molded to form a sealed space within the oxygen separation container. A plurality of inlet nozzles for receiving the mixture of oxygen and water are provided on or near the upper part of the first side wall, A heat exchanger located in or near the bottom of the inside of the oxygen separation container for cooling the mixture of oxygen and water, At least one oxygen outlet for producing oxygen separated from the mixture of oxygen and water, The system comprises at least one water outlet nozzle for producing water separated from the mixture of oxygen and water, The plurality of inlet nozzles are positioned at an angle of 30 to 60 degrees clockwise with respect to the flat portion in a cross-sectional view of the first side wall of the oxygen separation container, and are positioned during use to direct the fluid flow along the curvature of the upper or lower curved wall of the oxygen separation container and toward the opposing second side wall, thereby creating a cyclone effect. The third side wall has a coolant inlet port, and the fourth side wall has a coolant outlet port. The coolant inlet port and coolant outlet port are connected via an internal conduit. The internal conduit allows the flow of coolant through the oxygen separation container and functions as a heat exchanger or houses a heat exchanger in the oxygen separation container.

19. The oxygen separation container according to claim 18, wherein the oxygen separation container is constructed from a polymer material.

20. The oxygen separation container according to claim 18 or 19, wherein the plurality of inlet nozzles are located in a region defined by the upper 25% of the oxygen separation container in use.

21. The oxygen separation vessel according to any one of claims 18 to 20, further comprising at least one through-hole for receiving a lateral bracing element.

22. The oxygen separation container according to claim 21, further comprising a lateral bracing element received in the at least one through hole.

23. The oxygen separation container according to any one of claims 18 to 22, further comprising external sheet cladding covering at least a portion of the outer surface of the oxygen separation container.

24. The oxygen separation vessel according to claim 23, wherein the external sheet cladding is made of steel.

25. The oxygen separation vessel according to any one of claims 18 to 24, wherein the coolant inlet port is located below or near the third side wall, and the coolant outlet port is located below or near the fourth side wall.

26. The oxygen separation container according to any one of claims 18 to 25, wherein the plurality of inlet nozzles and the at least one water outlet nozzle are integral with the oxygen separation container and are constructed from the same material as the oxygen separation container.

27. The oxygen separation vessel according to any one of claims 18 to 25, wherein the plurality of inlet nozzles are positioned at substantially the same height.

28. The oxygen separation vessel according to any one of claims 18 to 27, wherein the oxygen separation vessel is rotationally molded in a single one-shot process.

29. The oxygen separation container according to any one of claims 18 to 28, wherein during use, the first side wall, second side wall, third side wall, and fourth side wall are each positioned vertically, and the cross-sectional shape obtained perpendicular to the first side surface is an ellipse with a flat portion.

30. The oxygen separation container according to any one of claims 18 to 29, wherein the oxygen separation container is constructed of high-performance hexane-density polyethylene.

31. The oxygen separation vessel according to any one of claims 18 to 30, further comprising a tapered collector located between the heat exchanger and the at least one water outlet nozzle.

32. The oxygen separation container according to any one of claims 18 to 31, wherein the heat exchanger is a tubular heat exchanger.

33. The tubular heat exchanger further comprises a sleeve arranged around it, The oxygen separation container according to claim 32, wherein the sleeve comprises an inlet, an outlet, and one or more baffle plates arranged to allow fluid to flow transversely around the heat exchanger during use.

34. A system for generating hydrogen, the system comprising an electrolytic cell stack connected to the oxygen separation container according to any one of claims 18 to 33.

35. The system according to claim 34, further comprising a pump connected to at least one water outlet nozzle, wherein the pump is located downstream of the oxygen separation vessel.

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