Integral, floating centrifugal reverse osmosis system for the desalination of saline aqueous solutions with intrinsic energy storage capability and energy recovery from friction losses.

Abstract

The invention relates to a centrifugal reverse osmosis system for the desalination of saline aqueous solutions such as seawater or brackish water. The system includes a rotating body that is primarily suspended by a float, enabling very large rotational diameters of up to 100 meters or more. This allows for membrane areas of up to several tens of thousands of square meters per unit. Due to the inherent energy recovery properties of centrifugal reverse osmosis, the very low-friction mounting, and additional energy recovery features, energy consumption close to the theoretical minimum of this method, approximately 1.9 kWh per cubic meter, can be achieved. With an average of approximately 2.2 kWh per cubic meter, only about 50% of the energy required by typical reverse osmosis systems is needed.Due to its design and low energy consumption, it is possible to operate economically with a reduced purified water yield of approximately 25 to 30%. This leads to intrinsic self-cleaning and enables a significantly longer service life for the expensive membrane material, as well as a considerable reduction in typical chemical additives. Overall, this can substantially and significantly reduce the environmental impact of the reverse osmosis process.

Description

[0001] The invention relates to a centrifugal reverse osmosis system for the desalination of saline aqueous solutions such as seawater or brackish water. The system includes a rotating body that is primarily suspended by a float, enabling very large rotation radii of up to 100 meters or more. This allows for the production of very large quantities of salt-free or low-salinity permeate water. Additionally, the invention incorporates an intrinsic energy storage system to ensure continuous day / night operation. Furthermore, friction and energy losses are largely utilized for additional purposes.

[0002] Approximately 97.4% of the world's available water resources consist of saline seawater. The average salinity of seawater is about 35 g / liter (brackish water: about 7.5 g / liter). Of the remaining 2.6% of freshwater, most is locked up in polar ice caps and glaciers. Less than 0.5% of the world's water resources are suitable for drinking and directly accessible. Access to clean drinking water is not guaranteed in all regions of the world. In the long term, this problem will worsen due to demographic trends. For health reasons, drinking water should have a salinity of no more than 0.01 percent. Water with a salinity of up to 0.05 percent is considered freshwater. Agriculture can tolerate up to 0.2 percent for irrigation. Desalination of seawater could be a possible solution.The higher the salt content of the water, the more difficult, environmentally damaging, energy-intensive, and therefore expensive it becomes for currently available technologies to remove the salt and produce drinking water or at least fresh water. As a result, large seawater desalination plants have been built for a long time and continue to be built today. The most common processes are multistage flash evaporation (MSF), multi-effect distillation (MED), vapor compression (VC), and reverse osmosis. Besides the environmental impact, cost is a major concern for seawater desalination. Water scarcity is particularly prevalent in regions with high temperatures and abundant sunshine. Some of these countries are wealthy, while many are not. It is therefore hardly surprising that large-scale seawater desalination plants are primarily located in affluent Arab states.Saudi Arabia, Kuwait, the Emirates, and Qatar produce almost half of the world's desalinated drinking water. While older thermal processes, consuming approximately 20 to 30 kWh per cubic meter of fresh water, are still largely used in these countries, newly constructed plants are increasingly based on the more energy-efficient principle of reverse osmosis, which now consumes between 3.5 and 4.5 kWh per cubic meter. The theoretical minimum energy consumption for this method is around 1.9 kWh per cubic meter, primarily electrical energy. Reverse osmosis was introduced in the 1970s and has evolved into a technology whose market share is steadily growing due to significant advances in membrane development and cost reduction. Reverse osmosis uses membranes that are permeable in one direction only, functioning similarly to a filter at the molecular level.When an aqueous solution is forced through such a membrane under high pressure, greater than the osmotic pressure of the salt water (typically between 55 and 70 bar, more recently up to approximately 80 bar), the majority of all salts, bacteria, and potentially other substances such as detergents, pesticides, and the like remain in the concentrate. Virtually pure water is separated by the membrane. The salt retention capacities of membranes from leading manufacturers such as Dow Chemical, Hydranautics, Osmonics, and Toray range between approximately 99.4 and 99.8%. Flow rates of such membranes, at sufficiently high pressure, range between approximately 800 and 1200 liters per day per square meter of membrane surface. Table 1 summarizes a typical percentage cost structure, with a 10-year depreciation period, for such modern reverse osmosis systems, with the electrical energy for the high-pressure pumps representing the main cost driver. Table 1 Investment costs 14% Membrane costs 7% Consumables costs 26% Energy costs 41% Personnel costs 1% Spare part costs 11%

[0003] Besides the high energy costs, the cost of consumables also plays a significant role in this technology. This primarily involves costs for additive chemicals required during operation to extend the lifespan of the materials, especially the membrane material. These include antifouling agents, anti-limescale agents, and anti-foaming agents. These chemicals are usually not removed from the concentrate discharge, meaning they almost always enter the environment along with the concentrated brine and can cause corresponding damage. Spare part costs mainly include the cost of necessary membrane replacement [approximately every 5 to 7 years (in exceptional cases, 13)] and the cost of the sensitive high-pressure pumps. To ensure the longevity of both components, significant costs for feedwater pretreatment are unavoidable in addition to the cost of the reverse osmosis unit itself.The pressure required for reverse osmosis is generated using technically complex high-pressure pumps. A significant disadvantage of a simple reverse osmosis system is that the concentrate outlet is also pressurized, resulting in a considerable loss of the previously applied energy during its discharge. Various efforts have been undertaken to recover the energy used in the concentrate's expansion process. For example, as described in German patent DE2907429, turbines have been employed to recover the energy contained in the concentration outlet and feed it back into the overall system. German patent DE3941133A1 pursues a similar objective, but describes a dual-pump system for energy recovery. Pressure exchanger systems are more widely used.Numerous technical implementations exist for this purpose; examples include the documents CN1994905; DE3719292; DE10327401; EP1508361; EP1631369; US3405641; US3431747; and US6540487. The more cost-effective turbine systems exhibit an energy recovery rate of approximately 30 to 40%, while the more expensive pressure exchanger systems achieve an energy recovery rate of 50 to 60%. Document US2006 / 0065597 describes a hydraulic motor-based energy recovery system in detail. Overall, the energy loss is considerable at this point, especially when not using the highest possible permeate yields, which in turn lead to faster clogging or wear of the membranes. To circumvent these difficulties, or...To significantly reduce energy loss, patent application DE3112647 proposes not using a pump system to generate the necessary pressure, but rather subjecting the reverse osmosis modules and their feeders, along with the liquid they contain, to centrifugal acceleration. After exiting the reverse osmosis modules, the concentrate is guided inwards within the rotating system, where the kinetic energy contained in the concentrate is largely recovered as drive power. In addition to the centrifugal force, the liquid, rotating in the largely closed system at an angular velocity in a plane perpendicular to the axis of rotation, experiences an additional inertial force as it moves radially inwards. This additional force results in energy recovery. Furthermore, the permeate, i.e., the fresh water, is expelled through nozzle outlets to assist the rotational movement with a recoil force.This energy recovery property is utilized in many centrifugal reverse osmosis (CRO) systems and represents the decisive advantage over simple single-stage reverse osmosis (SSRO) systems. Centrifugal reverse osmosis systems have been known for some time, and there are numerous technical implementation proposals. For example, Grenci describes a CRO system in US3400074, in which the saline water is set into rotation by a rotating hollow cylinder, and the resulting centrifugal force exerted on the liquid generates the necessary pressure in front of the semipermeable membrane. A similar principle, which sets the saline liquid into rotation but in which the membranes themselves are stationary, is described in ES2326024.Further CRO systems with different technical designs and specific technical advantages are disclosed in documents ES2299349; GB1308165; US3398833; US3567030; US3883434; US4230564; US4333822; US4886597; US6132613; WO98 / 36823; WO2021 / 071435; and WO2023 / 158503. A comprehensive technical and theoretical discussion can be found in publications DS1 and DS2. Many of the proposals either use only a single outer membrane or at least only a few layers, or employ typical reverse osmosis cartridges oriented differently to the centrifugal force to increase the membrane surface area. In publication DS3, Bergen et al. describe a typical stack structure of a multilayer membrane assembly. Despite the possibility of a multi-layer structure for the described systems, there is still a limitation on the total membrane area.Due to the mechanical bearings used for the rotating bodies, the resulting weight imposes strict technical limitations. Comparable typical flywheel masses with high rotational speeds reach their technical and economic limit at approximately 8 tons. Since the permeate flow rate per day and square meter of membrane area is only about 1 cubic meter, the solutions mentioned above are usually economically unfeasible. Attempts are being made to overcome this limitation, for example, using magnetic levitation technology as described in US2020 / 0017378 and US2020 / 0290897, or using a superconducting magnetic levitation system as described in the internet link IL1.

[0004] The gradual growth and clogging of the sensitive membranes is problematic in both classic reverse osmosis systems, where a large portion of the mass flow is perpendicular to the membrane surface, and in CRO systems, necessitating regular flushing or backwashing. To extend the intervals between these cleaning processes, or even eliminate them entirely, German patent applications DE2007474 and DE2837489 propose a slightly inclined orientation of the membranes relative to the centrifugal force acting at right angles. This aims to facilitate a rinsing process at the membrane surface using the primary water. A detailed investigation of this cleaning process can be found in publication DS4. In addition to these design approaches, significant efforts are being made to modify the membranes themselves to minimize and maintain their tendency to clogging.The lifespan of the membranes currently ranges from approximately 5 to 13 years, depending on the pressure load. This lifespan decreases with an increasing proportion of pure water recovery. Documents DS1 and DS5 postulate a roughly threefold increase in the membranes' lifespan when the proportion of pure water recovery is reduced from approximately 40% to 30%.

[0005] The energy efficiency of the CRO process compared to the energy consumption of the standard pressurized reverse osmosis process has been evaluated and calculated in several studies. Paper DS6 estimates annual energy savings of approximately 50% for a 20% purified water recovery rate compared to a typical purified water recovery rate of approximately 40%, starting at a production volume of approximately 12,000 US gallons per day, and savings of up to approximately 60% for a production volume of approximately 80,000 US gallons per day. Energy consumption is expected to increase with increasing purified water recovery. In contrast, according to Paper DS7, the specific energy consumption of the CRO process can be reduced by approximately 31% at 50% purified water recovery and by approximately 44% at a higher purified water recovery rate of 65%, meaning that the relative specific energy consumption decreases with increasing purified water recovery.According to our own research, specific energy consumption decreases with a decreasing proportion of pure water production.

[0006] To realize very large loads of 100 to more than 100,000 tons in a rotating or flywheel body, Werner Thoma described a flywheel-based energy storage system with an electric motor / generator device in patent DE102005044123. This system is characterized by the fact that the flywheel has a floating body with a rotationally symmetrical outer surface, which is rotatable about its axis of rotation and is mounted to float in water. The floating body has a significantly smaller diameter than the flywheel rim. Building on this generic principle, further floating-body-based flywheel systems have been disclosed in patents WO2011138480, EP3205876, and WO2011008153. Hennig describes a similar system in patent DE102024000621.4. A similar system is used, in which the energy loss over time is significantly reduced by decreasing the volume of the float and the associated reduction in the frictional area and velocity at the liquid / float shell interface. The float floats in a gravitational fluid with a significantly higher density than water. This means that the storage capacity is not limited to a single day / night cycle, but can be bridged efficiently and economically for several days (up to 12).

[0007] In addition to desalination processes for fresh and drinking water, reverse osmosis, in combination with forward osmosis or reverse electrodialysis, can also be used for energy storage. Falah et al. describe such a system in German patent DE102021107575, which can be directly integrated into wind turbines. Energy generation through forward osmosis is well-documented, and a large difference in salinity between the two liquids is highly advantageous. For example, German patent DE102014225190 describes a process that produces a more concentrated brine solution from saltwater by supplying energy, with fresh water also being generated as a byproduct. Electrical energy can then be generated from the combination of saltwater and brine solution in a forward osmosis process or reverse electrodialysis.

[0008] The present invention aims to provide a centrifugal reverse osmosis system capable of producing very large quantities of drinking or fresh water from seawater or brackish water, without the unfavorable ratio of mechanical design to usable semipermeable membrane surface area that is necessary according to the current state of the art. The objective is to provide a rotating body with a very large outer circumference, ranging from approximately twenty to several hundred meters, or even reaching approximately 1000 meters. Furthermore, a multitude of membrane or reverse osmosis cells should be arranged staggered or stacked on its outer surface, without the centrifugal force acting on the inner and outer cells differing too greatly and being sufficiently large for a good purified water permeate flow across the entire sequence.Additionally, the system should be designed to allow energy absorption during daylight hours while also storing the necessary energy for operation during the night. This will enable 24-hour operation using photovoltaically generated solar power without the need for additional energy storage, such as batteries or similar devices. Energy losses resulting from unavoidable friction and the inherent pressure drop within the system should be minimized. The resulting residual energy loss, which leads to a temperature increase within the system, should be used for further energy recovery.

[0009] These problems are solved by providing an integral or integrated reverse osmosis system for desalinating saline aqueous solutions such as seawater or brackish water. The system is characterized in that the aqueous saline solution according to claim 1 is fed into a system comprising a basin filled with either water, a heavy liquid, a thermofluid, or combinations thereof. A rotating body with a float, having a rotationally symmetrical outer surface, can float and be rotatably mounted in the basin. The rotating body has a much larger circumference above the liquid surface compared to the float. A centrifugal reverse osmosis unit is attached to the unwetted outer edge of the rotating body, along with a flywheel.The basic structure of the system is entirely analogous to the flywheel design for energy storage as disclosed in DE 102005044123 or DE102024000621.4. Overall, the flywheel mass contained in the flywheel ring is relatively less significant than in the aforementioned documents, since the energy output is only sufficient to largely provide the energy for the reverse osmosis process, including friction losses, during nighttime operation. According to the invention, however, it should be high enough to ensure a sufficient rotational speed for almost this entire period.The volume of the floating body is designed such that the total mass of the displaced fluid equals or only slightly falls short of the total mass of the rotating system, including the floating body, the cantilever supports, the additional flywheel mass, the displacement mass (see below), the mass of the reverse osmosis system, and any pumps, balancing weights, piping systems, control units, and power transmission systems. This results in the entire unit floating like a ship in the aforementioned basin. Therefore, the rotating body according to the invention does not require a massive and costly load-bearing axle structure, which all alternative systems according to the prior art exhibit. To ensure inherent stability, only comparatively small and therefore cost-effective bearings are necessary to fix the axis of rotation.The fluid within the basin primarily acts as a bearing for the relatively large total mass of the rotating body, with the axis of rotation generally arranged parallel to the direction of gravity for design reasons. A horizontal orientation of the axis of rotation is also possible in principle and is expressly included in this invention. In this case, the floating body is submerged to approximately less than half its circumference, thus eliminating the need for any sealing measures at the outer bearings. If the entire floating body is submerged, the bearings must be designed to be liquid-tight. The advantage of such a design is that two rotating rings, each with a corresponding reverse osmosis system, can be mounted to the left and right of the floating body. However, the vertical orientation is generally easier to implement technically. The energy supply, or rather...Optional power generation can be achieved either by an electric motor / generator device mounted in the outer region of the rotating body, as proposed in DE102005044123, or preferably by a magnetic levitation device in the outer or outer region of the rotating body. The buoyancy of the floating body in the liquid should not be 100%, but rather between 70% and 99.99% of the total mass of the rotating system, so that the remaining weight is compensated by the magnetic levitation device, thus keeping the system suspended and firmly on a rotational path. Guidance via such a magnetic levitation system stabilizes the inherent stability of the rotating body and relieves the remaining lateral forces in the bearings.

[0010] If the goal is to recover friction losses through a thermal energy recovery process, a high-temperature heavy fluid with a low kinematic viscosity, as described in German patent DE102024000621.4 or similar, is recommended. Despite the higher initial investment, this design offers the advantage of significantly smaller friction surfaces and a smaller diameter for the float, thus greatly reducing energy loss. In contrast, using a thermal fluid only allows for thermal energy recovery, but the additional investment required is considerably lower than with water.Depending on the size of the rotating body and the membrane surfaces that can be installed on it—that is, the higher the overall mass—the remaining weight force can be transferred to one or more rotational tracks via the corresponding chassis units and their support magnets. Lateral stabilization is achieved using guide magnets commonly found in magnetic levitation technology. Integrating such guide magnets into the overall chassis may eliminate the need for a central bearing of the rotational axis at the top of the rotating body. Thus, a bearing is only required at the bottom of the rotational axis, which is almost 100% pressure-relieved and only has to absorb lateral forces (minor imbalances) and gyroscopic effects. Reference should be made here to the document DE102024000621.The four listed emergency braking and emergency devices should be explicitly pointed out, and should be included and supplemented in a similar manner in the system described here.

[0011] The reverse osmosis unit itself can preferably be constructed in a stacked configuration, with a recurring sequence consisting of an inlet area with integrated spacers, followed by an adjacent membrane surface, followed by a permeate area with integrated spacers, and finally by an impermeable end layer. The permeate areas are interconnected by several outflow channels and merged into a single overall permeate outflow channel. The rotational speed of the rotating body and the number of stack levels are selected such that a rotational speed of between 500 and 280 km / h, preferably between 450 and 380 km / h, can be achieved on the outer surface of the stack, and a circumferential speed of between 420 and 280 km / h, preferably between 420 and 350 km / h, can be achieved on the inner surface of the stack.The goal of these velocity specifications is to achieve a pressure level of approximately 50 to 80 bar at the membrane surfaces to ensure a consistently high permeate flow without causing the membrane sheets to burst. As an alternative to this stacked design, commercially available reverse osmosis cartridges or modules can also be stacked in the direction of the centrifugal forces, for example, according to the basic design described in US2020017378A1 and US20200290897. In this case, the cartridge length or the length of the cartridge sequence should be dimensioned so that the rotational velocity is approximately 350 km / h at the inner end and approximately 420 km / h at the outer end of the cartridges.

[0012] In order to maintain the aforementioned rotational speeds as far as possible and continuously for continuous operation, the rotating bodies according to claim 3 are designed such that the flywheel in the unwetted outer area is sufficiently massive to maintain the outer circumferential speed of at least 280 km / h during a day-night cycle even with reduced external energy input during the nighttime dark phase, whereby during this period the energy consumption of the reverse osmosis process and any friction losses are utilized by the amount of energy stored in the rotating flywheel and which can be released during the decelerating rotational speed.During the night phase, maintaining the necessary rotational speed for the reverse osmosis process, particularly the minimum rotational speed, can be achieved additionally by a built-in weight mass shift within the rotating body, according to claims 3 and 4, from the outer area of ​​the flywheel towards the central region of the rotating body. Such a mass shift, aimed at increasing the slowing rotational speed, is generally known in figure skating during a fast spin. For example, the initially extended arms are brought close to the body, thereby increasing the rotational speed without any additional energy input. When the arms are brought close to the body, the skater's moment of inertia decreases. Since the angular momentum is conserved, the angular velocity ω of the rotation increases.This pirouette effect, based on the law of conservation of angular momentum, can be achieved in rotating bodies using various mass displacement devices. One method involves using a displacement unit to move a solid body towards or away from the center of rotation to control the rotational speed. A simpler technical approach is to pump a quantity of liquid. According to claim 4, water, a heavy liquid, or combinations thereof can be transferred from a main storage tank within the unwetted outer area to a storage tank within the floating body using a pump or compressed air system. During the daytime phase, when the entire rotating system is absorbing energy, the liquid can be transported back.Optionally, an additional storage tank can be attached to the outer edge of the rotating body. When there is excess power, this tank is filled with water or heavy fluid from the main storage tank, thus acting as an additional energy storage device. When the excess energy is dissipated, the heavy fluid is transferred back to the main storage tank, creating a battery-like effect. Besides water, the use of a heavy fluid is particularly preferred to minimize volume. This allows for the use of highly concentrated salt solutions in water, such as sodium polytungstate solutions with a density of approximately 3.1 g / cm³. 3 or Clerici solutions with densities up to 4.25 g / cm³ 3 or Thoulet solutions with a density of approximately 3.2 g / cm³ 3among others. To prevent disruptive sloshing, appropriate anti-sloshing balloon inserts must be used. According to claim 5, the energy absorption and, if applicable, energy output of the rotating body is achieved either by means of an electric motor / generator device, wherein preferably a circular arrangement of magnets and / or coils fixed to the rotating body and a rotationally fixed circular arrangement of coils and / or magnets are arranged such that the magnets and coils face each other with a gap between them and form a translational motor / generator system that runs around the rotating body. This type of energy transfer is preferably used for smaller units; for larger and especially very large units, the energy exchange is advantageously implemented via a magnetic levitation system, in which case the floating body only provides buoyancy for approximately 90 to approximately 100 degrees.The rotating body provides 99.95% of the total mass of the rotating system, and the remaining lifting force for low-friction movement is provided by the magnetic levitation system, which is preferably located on the outer surface of the rotating body. The required speed of approximately 380 to 420 km / h is state of the art for Transrapid and Maglev systems, meaning that their track systems, chassis, and other technology can be used directly.

[0013] According to claim 6, the rotating body is typically characterized by being rotatably mounted at the top and bottom in fixed bearings around the axis of rotation. The inflow and outflow of the saline solution and concentrate occur at the center of the rotating body, with the solution being transported under sufficient pressure along the cantilever supports towards the unwetted outer area into the reverse osmosis system and back. The inlet of the reverse osmosis system is positioned significantly closer to the center of rotation than the concentrate outlet to further drive the circulation flow and to continuously support a certain degree of membrane self-cleaning. The central axis of rotation is designed as a robust double-pipe construction, with the cross-sectional area of ​​the inlet being larger in proportion to the percentage of pure water produced compared to the concentrate outlet.To overcome any flow resistance, the inflow must have a sufficiently high inlet pressure of a few bar, which is ensured by an external pumping system. Due to the tilt of the reverse osmosis membrane surfaces relative to the vertical, an additional pressure increase can occur in the central area of ​​the concentrate outflow stream, which is then subjected to energy recovery at the outlet via a turbine solution. The angle of tilt of the reverse osmosis membrane surfaces relative to the vertical should be between approximately 0.3° and 3°, preferably between approximately 0.8° and 2.2°, so that at an operating pressure of approximately 80 bar, an additional pressure of approximately 0.4 to 4.2 bar builds up at the membrane outlet in the concentrate stream.

[0014] According to claim 7, the open, initially pressure-reduced permeate region is bounded by a convex or slightly V-shaped collection wall, so that the permeate collects centrally and, after being discharged through corresponding permeate channels, passes through a nozzle-like, almost tangentially arranged outlet opening, thereby generating a recoil force that supports the rotation. The permeate discharge can be continuous or pulsed. If the permeate is discharged in pulses through the nozzles to ensure better recoil and momentum transfer, a liquid collection region must be placed upstream of the nozzles. In this region, a high pressure can build up, at least partially, due to the existing centrifugal force, since it is located at the outermost radius of rotation. The height of the V-shaped collection wall can range from approximately 50 cm to several meters. However, wall heights of approximately...A height of 150 cm is preferred, and if greater heights are desired, it is advisable to stack the module stacks in multiple tiers. Two to four tiers have proven suitable. To improve permeate flow and its concentration towards the collection lines, it has been shown that the collection walls should have a slightly steeper inclination than the membrane surface. Angles between approximately 2° and 4° are advantageous. To avoid excessively increasing the cell depth within the stack, the collection walls are divided vertically into several segments. This also has the advantage of providing more space for the permeate channels. A division into vertical segments of approximately 50 cm is preferred. The permeate channels of the stacked units are arranged alternately in a forked pattern (see drawings).Overall, the cross-sections of the collection lines and permeate channels, as well as the volume of the liquid collection area and the pure water-containing module area, must be designed to be large enough to prevent liquid build-up and the resulting increased back pressure on the back of the membranes. To ensure the necessary pressure conditions for a sufficiently large and economical permeate flow both on the rotating ring side facing the center of rotation and on the outer edge of the rotating ring, the ring area where the module stacks are mounted should occupy approximately 10 to 15% of the rotation radius. This is not the case, for example, in documents US2020 / 0017378 and US2020 / 0290897, where the modules are arranged over a radius of approximately 77%.Thus, nearly 80% of the modules are located in an area where only a low permeate flow is possible without causing the membranes to burst at the outer edge, making this design uneconomical in terms of the ratio of module area to permeate flow rate. If we take, for example, an inventive unit with an outer radius of approximately 25 m and thus a diameter of 50 m as a basis, then a ring width of approximately 2.5 to 3.75 m is available to accommodate the module stacks. With a cell depth of approximately 3 to 6 cm per individual cell of the stack, which is necessary to structurally absorb the prevailing forces and to accommodate the aforementioned misalignments, approximately 40 to 120 individual cells can be stacked one behind the other. The final containment wall must be designed to be correspondingly robust to absorb all the pressure forces caused by the centrifugal force.In addition to the main spacers between the individual containment walls, corresponding spacer fabrics must be installed in front of and behind the membranes. Document DS7 summarizes their optimization possibilities. Using two module layers of 150 cm each and a membrane area coverage of approximately 90%, this can result in a coverage of approximately 15,000 to 46,000 m². 2 Membrane surface area per unit can be installed with an average production rate of 15,000 to 25,000 m² 3Pure drinking water per 12 hours per day. This production volume can be further increased during the night phase, if the production rate is reduced, or doubled if sufficient electricity is available. For large-scale plants with a capacity of approximately half a million cubic meters per day, roughly 20 to 25 such units would be required. It should be noted that a significant pressure increase of approximately 5.5 to a maximum of approximately 8 bar occurs within the membrane stack. Depending on the position, different membrane types can be used to optimize the balance between permeate flow and membrane costs at the respective pressure level. A small percentage of the total energy loss is due to frictional losses of the floating element in the supporting fluid, provided that the fluid is inexpensive water.Care must be taken to ensure that the water layer thickness between the floating body wall and the pool wall is sufficiently large to produce a lamellar, turbulence-free flow pattern. A purely laminar Couette flow is particularly preferred, but a laminar Taylor-Couette flow can also be achieved without excessively increasing friction losses. If a thermofluid is used, its kinematic viscosity must not significantly exceed 1 cPs at the operating temperature.

[0015] In large-scale systems with multiple units, it can be advantageous, according to claim 8, to utilize the energy losses resulting from frictional losses of the rotating float in the liquid-filled basin, coupled with a simultaneous temperature increase. For this purpose, the basins must be thermally insulated as effectively as possible and equipped with a heat exchanger. The dissipated heat energy can be utilized in different ways depending on the temperature level. Examples include additional thermal evaporative desalination or utilization according to the method described in German patent DE102014225190. Similar processes using large-area evaporation basins, such as those used in sea salt production, can also be employed here to obtain a highly saline brine solution.Here, the combination of the available heat energy from the units and solar-driven natural evaporation is easily achievable, as only low requirements are placed on the temperature level of the unit waste heat.

[0016] The following is a description of an exemplary embodiment with reference to drawings. All subsequent explanatory illustrations are schematic and symbolic only and are not to scale. They serve to explain the basic principles of the device according to the invention, whereby any modifications that lead to similar results are not excluded and are included in the invention. Some angles to be shown have only a few degrees, which would be difficult to discern in the illustrations; therefore, these angles are shown significantly larger for better visibility, and their true size can be found in the text above. Fig.Figure 1 shows a cross-sectional view of the main components of the reverse osmosis system 1 according to claim 1. Alternative embodiments, insofar as they differ fundamentally, are shown schematically to the left and right of the axis of rotation 2. The saline aqueous solutions, such as brackish or seawater, are first fed via an inlet 3 to a purification or pretreatment unit 4, which is standard for reverse osmosis systems. If necessary, additives such as antifouling agents, anti-limescale agents, and anti-foaming agents can be added to the treatment stream here, although to a significantly lesser extent than in comparable conventional reverse osmosis systems. The liquid stream then passes through a first pressure boosting unit 5 to generate sufficient pre-pressure. The solution is then fed via a pipe 5A and a support bridge 6 to the central inner pipe 7 of the double-pipe construction 8.The double-tube structure 8 serves as the upper part of the central axis or shaft of the rotating body 9 and is additionally held in a pivot bearing 10 centrally located in the support bridge 6. This bearing can be a low-friction roller or ball bearing. The pivot bearing 10 and the support bridge 6 only need to be dimensioned to withstand any residual imbalances and the forces acting during operation on the translational motor system or the magnetic levitation technology. In addition to its own weight, the support bridge 6 must, of course, bear the weight of the water-filled pipes. If it is designed as a closed disc structure, it can simultaneously serve as a roof structure to protect against environmental influences such as rain or dust storms. In this case, a suitable roof slope must be incorporated.The rotating body 9, which carries the reverse osmosis modules 11A and 11B, floats in a concrete-lined basin 12 embedded in the ground 13 (shown in dashed lines). The basin 12 is rotationally symmetrical about a central axis 2. A thermal insulation layer 14 is incorporated into the concrete structure of the entire basin 12 to retain the heat generated by frictional losses within the basin 12. The heating of the supporting fluid 15 is cooled by a heat exchanger system 16 additionally incorporated in front of the insulation layer 14, or the heat is dissipated for energy recovery. The essential component of the reverse osmosis system according to the invention, compared to prior art techniques for CRO systems, is the floating body 17. The floating body 17 has a relatively thin wall compared to its size.The vessel is made of steel or reinforced concrete and should be coated to prevent corrosion, reduce friction, and provide protection. It is otherwise essentially hollow, although, particularly in the lower section, the walls may be reinforced and / or equipped with internal support elements 18 to increase strength, especially in the case of very large floats, due to the increasingly higher hydrostatic pressure conditions and to prevent buckling. The ratio of the float radius to the height of the submerged hollow cylinder portion should be approximately between 2 and 3.5, preferably between 2.4 and 3. The aim of this aspect ratio is to achieve the smallest possible radius in order to minimize the outer surface velocity for friction reduction, while simultaneously maximizing the internal volume and minimizing the vessel wall area to reduce weight and the outer surface area of ​​the vessel wall.The submerged hollow cylinder portion is also thermally insulated from the upper area 19. Around the upper edge of the float 17, several supports or cantilever arms 20 are attached to the float 17 in a rotationally symmetrical arrangement with respect to the central axis 2. These extend horizontally and radially to the actual annular module support ring 21 or the somewhat wider flywheel ring 22. The supports 20 are rigidly connected to the hollow cylinder 17, and additional tension struts 23 may need to be incorporated inside the cylinder 17 to absorb centrifugal forces. The primary function of the supports or cantilever arms 20 is to lift the module support ring 21 and the massive flywheel ring 22. If very large projections are required between the center of rotation 2 and the edge of the rotating body 24, or if the ring structure is particularly massive and heavy, the supports or cantilever arms 20 can also be designed as a closed support disc.This can be particularly advantageous with regard to improved aerodynamics. In addition to the upper bearing 10, the rotating body 9 also has a sufficiently robust pivot bearing 25 at the lower axis of rotation. However, the main stabilization of the rotational movement is ensured by a magnetic levitation system 26, which carries only a small proportion of the load but, due to the external rail guidance, provides excellent stabilization of the rotating body's movement. This stabilization is essentially ensured by the lateral guide magnets 27. The track 28 of the track system 29 is constructed using conventional reinforced concrete construction, possibly supported by stilts, and equipped with the long stators 30. The bogies 31, which are rigidly or slidably connected to the entire rotating ring 32 with vibration damping, have the necessary load-bearing 33 and guide magnets 27.If this system is insufficient for energy input and, if necessary, energy output, further magnet / coil systems 34 can be attached to the rotating ring 32. Within the flywheel ring 22, corresponding movable heavy-duty mass sections are integrated for additional angular velocity control. Two alternative embodiments, among others, can be used for this purpose. The left side of the rotating body of the... Fig.Figure 1 shows the pump- or pressure-regulated system with a corresponding heavy fluid. For this system, two different multi-cavern container arrangements or two rotationally symmetrical ring-shaped container sections 35A and 35B are incorporated into the flywheel ring 22. Additionally, a rotationally symmetrical receiving tank 36 is located in the central float cylinder 17, allowing the heavy fluid to be pumped back and forth. The fluid transport is regulated either by pumps 37 or by compressed air control 38A, 38B, and 38C. The ease of control of this system is offset by the risk of sloshing in the caverns, which can be prevented by appropriately safe and stable integrated balloon structures. On the right side of the depicted rotating body 9 in Fig.Figure 1 additionally depicts the second alternative of a movable heavy-duty mass area. Here, a solid mass unit 39, e.g., made of iron, steel, or lead, is moved back and forth by means of a rail-guided sliding system 40. Such a system is technically more complex, but has the advantage that, due to the high density of the material of the mass unit 39, significantly smaller volumes need to be moved, or, with a similar volume compared to liquid transfer, significantly larger mass fractions are available and can be moved. Once the saline aqueous solution has reached the double-pipe structure 8, it first passes through the inner pipe 41 to the distribution pipes 42, which are attached along the supports or cantilevers 20, and then, under continuous pressure increase, reaches the reverse osmosis module units 11A or 11B.There, the liquid is fed to the individual reverse osmosis module cells 44A or 44B via corresponding dividing devices 43A or 43B. In these cells, the pure or fresh water is separated from the saline aqueous solution, while the more concentrated brine is also formed. Two flow paths are now created. The concentrated brine is combined in a collection area 45A or 45B and returned to the central casing pipe 47 almost to the center of rotation via reflux pipes 46. During this process, the high pressure is reduced, and the stored energy is almost completely recovered automatically, at least for the concentrate flow. Due to the inlet pressure and the inclination of the reverse osmosis module cells 44A, the resulting outlet pressure should be adjusted as needed.This should be sufficient to economically operate a more cost-effective turbine system 48 for residual energy recovery at the end of the discharge line 5B, which also runs along the support bridge 6. If several units are operated simultaneously in parallel, a common energy recovery turbine should be used for efficiency reasons. The brine then leaves the unit and, after final treatment, such as pre-dilution, is discharged back into the sea over a wide area. The purified water stream is also collected in corresponding collection areas 49A or 49B and, if applicable, transferred to a liquid collection area 50 in the case of pulsed discharge. The purified water is then discharged via nearly tangentially arranged nozzles 51 through valves that are pulsed in short intervals [e.g., after each revolution (in the example above, approximately every 1 / 48th of a minute)].The nozzles are not ideally horizontal and perpendicular to the radius of rotation, but rather angled a few degrees downwards and towards the clean water collection device 52. The collected clean water is discharged and, after final treatment, supplied to the desired application. The assemblies of the present invention have total masses ranging from approximately a few hundred to a few tens of thousands of tons and must therefore be protected very effectively and quickly from significant imbalances by a balancing device 53. By way of example, in the above-mentioned example, the total weight of the rotating body, including the mass of the float, the support mass, and the water-filled module mass, can be roughly estimated at 2500 tons, and the additional flywheel mass at roughly 4500 tons, resulting in a total weight of approximately 6500 tons. A float 17 with a radius of approximately 9 m and an immersion depth of approximately 26 m would thus support approximately 98% of the total weight.Such a system therefore has only about 1 / 10th the mass of those used in documents DE102005044123 or DE102024000621.4. Nevertheless, reference should be made here to the safety measures and emergency braking devices listed in document DE102024000621.4. Such and supplementary protective devices are also to be installed in the present rotating body according to the invention.

[0017] As described above, two different types of reverse osmosis systems can be installed on the module support ring 21. The horizontal installation of commercially available reverse osmosis cartridges, based on US2020 / 0017378 and US2020 / 0290897, is technically simpler. This installation variant has the disadvantage that a significant empty volume of at least 21.5% for a cubic arrangement and 9.3% for a hexagonal arrangement is unavoidable when stacking the elongated cartridge tubes. This empty volume is further increased by the radii increasing from the inner to the outer area of ​​the module support ring 21. Despite the simpler fluid flow in this configuration, a stacked arrangement of the module cells is preferred here and will be described in [reference to relevant document / section]. Fig. 2. will be described in more detail, with the fluid flows illustrated by corresponding arrows. Fig.2A shows schematically and only partially, here two cells, a side view of cell packing 54 and Fig. Figure 2B shows in plan view the angulation of the left and right sides of the water-impermeable cell back wall 55 and the arrangement of the clean water outlet channels 56 of six cells. Fig.Figure 2A shows the individual module cells 57, each extending laterally over a small circumferential area of ​​approximately one to a few meters, with the saltwater-bearing primary area 58 in which a corresponding spacer fabric 59 is embedded. This fabric performs both a supporting function and the function of ensuring a uniform flow distribution. The membranes 60 delimit the primary area 58 and are mechanically stabilized by additional support fabrics 61. Further support elements 18 are incorporated in a larger grid. The primary area 58 is slightly inclined so that the fluid flow accumulates at the lower end of the individual module cell 57 in a collection area 45 due to the slightly increased centrifugal forces and flows into the return pipes 46. The inflow to the upper area of ​​the primary area 58 occurs via the corresponding distribution devices 43.The secondary compartment 62, which carries pure water, connects behind the membrane 60 and is segmented 63 to allow for a slightly steeper inclination of the water-impermeable cell back wall 55 relative to the primary compartment inclination, without taking up too much volume. This increased inclination is intended to ensure the confluence of the pure water into the outlet channels 56 at the lower end of the segments 63. The secondary compartment is also filled with a spacer tissue 59A. Fig.As shown in Figure 2B, the cell back wall 55 is either slightly convex or slightly V-shaped to concentrate the clean water flow in the center 64 of the cell back wall 55. The individual outlet channels 56 are arranged in a fork-like manner and are grouped into corresponding collection areas 49 to finally exit the rotating body 9 in a pulsed manner with a corresponding recoil impulse. The number of outlet channels 56 can be quite large, depending on the number of cells arranged in series in the stack. Therefore, care must be taken to ensure that the intermediate areas are sufficiently large to prevent an excessive increase in flow resistance. They are positively connected to the cell back walls 55, thus contributing significantly to the support function within the module block. Cited non-patent literature DS1 Wild, Peter Martin. 1996. „Development, Optimization and Implementation of the Design for a Centrifugal Reverse-Osmosis Desalination System.“ dissertation, Ottawa: National Library of Canada. DS2 Wild PM, Vickers GW, Djilali N. The fundamental principles and design considerations for the implementation of centrifugal reverse osmosis. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering. 1997;211(2):67-81. doi:10.1243 / 0954408971529566 DS3 A Bergen, T.M Fyles, D.S Lycon, G.W Vickers, P Wild. Flux enhancement in reverse osmosis using centrifugal membrane separation. Journal of Membrane Science, Volume 176, Issue 2, 2000, 257-266. doi:10.1016 / S0376-7388(00)00473-7. DS4 T.M Fyles, D.S Lycon. Fouling reduction using centrifugal membrane separation. Journal of Membrane Science, Volume 176, Issue 2, 2000, 267-276. doi:10.1016 / S0376-7388(00)00472-5. DS5 Leon Awerbuch, Sherman May, Randall Soo-Hoo, Victor van der Mast. Hybrid desalting systems. Desalination, Volume 76, 1989, 189-197. doi:10.1016 / 0011-9164(89)87046-8. DS6 Peter M. Wild, Geoffrey W. Vickers. The technical and economic benefits of centrifugal reverse osmosis desalination. Desalination, Volume 89, Issue 1, 1992, 33-40. doi:10.1016 / 0011-9164(92)80150-8. DS7 William B. Krantz, Tzyy Haur Chong. Centrifugal reverse osmosis (CRO) - a novel energy-efficient membrane process for desalination near local thermodynamic equilibrium. Journal of Membrane Science, Volume 637, 2021, 119630. doi.org / 1 0.1 016 / j.memsci.2021.119630. DS8 A.H. Haidari, S.G.J. Heijman, W.G.J. van der Meer. Optimal design of spacers in reverse osmosis. Separation and Purification Technology, Volume 192, 2018, 441-456, doi:1 0.1 016 / j.seppur.2017.1 0.042. IL1 https: / Iwww.centrifugalsolutions.com ZITATE ENTHALTEN IN DER BESCHREIBUNG

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 2907429

[0003] DE 3941133A1

[0003] CN 1994905

[0003] DE 3719292

[0003] DE 10327401

[0003] EP 1508361

[0003] EP 1631369

[0003] US 3405641

[0003] US 3431747

[0003] US 6540487

[0003] US 2006 / 0065597

[0003] DE 3112647

[0003] US 3400074

[0003] ES 2326024

[0003] ES 2299349

[0003] GB 1308165

[0003] US 3398833

[0003] US 3567030

[0003] US 3883434

[0003] US 4230564

[0003] US 4333822

[0003] US 4886597

[0003] US 6132613

[0003] WO 98 / 36823

[0003] WO 2021 / 071435

[0003] WO 2023 / 158503

[0003] US 2020 / 0017378 [0003, 0014, 0017] US 2020 / 0290897 [0003, 0011, 0014, 0017] DE 2007474

[0004] DE 2837489

[0004] DE 102005044123 [0006, 0009, 0016] WO 2011138480

[0006] EP 3205876

[0006] WO 2011008153

[0006] DE 102024000621.4 [0006, 0009, 0010, 0016] DE 102021107575

[0007] DE 102014225190 [0007, 0015] US 2020017378A1

[0011] Zitierte Nicht-Patentliteratur

[0000] Wild, Peter Martin. 1996. „Development, Optimization and Implementation of the Design for a Centrifugal Reverse-Osmosis Desalination System.“ dissertation, Ottawa: National Library of Canada

[0017] Wild PM, Vickers GW, Djilali N. The fundamental principles and design considerations for the implementation of centrifugal reverse osmosis. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering. 1997;211(2):67-81. doi:10.1243 / 0954408971529566

[0017] A Bergen, T.M Fyles, D.S Lycon, G.W Vickers, P Wild. Flux enhancement in reverse osmosis using centrifugal membrane separation. Journal of Membrane Science, Volume 176, Issue 2, 2000, 257-266. doi:10.1016 / S0376-7388(00)00473-7

[0017] T.M Fyles, D.S Lycon. Fouling reduction using centrifugal membrane separation. Journal of Membrane Science, Volume 176, Issue 2, 2000, 267-276. doi:10.1016 / S0376-7388(00)00472-5

[0017] Leon Awerbuch, Sherman May, Randall Soo-Hoo, Victor van der Mast. Hybrid desalting systems. Desalination, Volume 76, 1989, 189-197. doi:10.1016 / 0011-9164(89)87046-8

[0017] Peter M. Wild, Geoffrey W. Vickers. The technical and economic benefits of centrifugal reverse osmosis desalination. Desalination, Volume 89, Issue 1, 1992, 33-40. doi:10.1016 / 0011-9164(92)80150-8

[0017] William B. Krantz, Tzyy Haur Chong. Centrifugal reverse osmosis (CRO) - a novel energy-efficient membrane process for desalination near local thermodynamic equilibrium. Journal of Membrane Science, Volume 637, 2021, 119630. doi.org / 1 0.1 016 / j.memsci.2021.119630

[0017] A.H. Haidari, S.G.J. Heijman, W.G.J. van der Meer. Optimal design of spacers in reverse osmosis. Separation and Purification Technology, Volume 192, 2018, 441-456, doi:1 0.1 016 / j.seppur.2017.1 0.042

[0017] https: / Iwww.centrifugalsolutions.com

[0017]

Claims

Integral or integrated reverse osmosis system for the desalination of saline aqueous solutions, characterized in that a saltwater source is provided and the system has a basin that is filled either with water or a heavy liquid or a thermofluid or combinations thereof, so that a rotating body with a float having a rotationally symmetric outer surface can float and be rotatably mounted in the basin, wherein the rotating body has a much larger circumference above the liquid surface in contrast to the float, and a centrifugal reverse osmosis unit is attached to the unwetted outer edge region of the rotating body next to a flywheel. A rotating body with a reverse osmosis unit according to claim 1, characterized in that the reverse osmosis unit is constructed in a stack-like manner, wherein a recurring sequence is maintained, consisting of an inlet area with integrated spacers, followed by an adjacent membrane surface, followed by a permeate area with integrated spacers, and finally followed by an impermeable end layer, wherein the permeate areas are interconnected by several outflow channels and merged into a single overall permeate outflow channel. The rotational speed of the rotating body and the number of stack levels are to be selected such that a rotational speed of between 500 and 280 km / h, preferably between 450 and 380 km / h, can be set on the outer surface of the stack, and a circumferential speed of between 420 and 280 km / h, preferably between 420 and 350 km / h, can be set in the inner area of ​​the stack.A rotating body according to one of the above claims, characterized in that the flywheel in the unwetted outer area is sufficiently massive to maintain the outer circumferential speed of at least 280 km / h during a day-night cycle, even with reduced external energy input during a nighttime dark phase. During this period, the energy consumption of the reverse osmosis process and any friction losses are utilized by the energy stored in the rotating flywheel, which can be released during the deceleration of the rotational speed.During the night phase, the maintenance of the necessary rotational speed for the reverse osmosis process, in particular the minimum rotational speed, can be additionally achieved by a built-in weight mass displacement within the rotating body by means of a liquid pump system or a mass displacement system from the outside of the rotating body towards the central area of ​​the rotating body. A liquid pumping system according to claim 3, characterized in that water or a heavy liquid or combinations thereof is transferred from a main storage tank within the unwetted outer area to a storage tank in the floating body by means of a pumping device or a compressed air device. During the daytime phase, during an energy absorption period of the entire rotating system, the liquid can be transported back. Optionally, a further storage tank can be attached to the outer edge of the rotating body to be filled with the liquid or heavy liquid from the main storage tank when there is excess power, thus acting as an additional energy storage device, whereby when the excess energy is dissipated, the liquid is transferred back to the main storage tank. A rotating body according to one of the above claims, characterized in that the energy absorption and, optionally, energy output is carried out either by means of an electric motor / generator device, wherein preferably a circular arrangement of magnets and / or coils fixed to the rotating body and a rotationally fixed circular arrangement of coils and / or magnets are arranged such that the magnets and coils are opposite each other with a gap between them and form a translational motor / generator system which runs around the rotating body, or that the energy exchange takes place via a magnetic levitation system, wherein in this case the floating body only provides buoyancy for approximately 90 to 99.95% of the total mass of the rotating system and the remaining lifting force for low-friction movement is provided by the magnetic levitation system. A rotating body according to one of the above claims, characterized in that it is additionally rotatably mounted at the top and bottom in fixed bearings about the axis of rotation, wherein the inflow and outflow of the saline solution and the concentrate take place in the center of the rotating body, wherein the solution transport, subjected to a sufficiently high pre-pressure, takes place along the cantilever supports towards the unwetted outer area into the reverse osmosis system and back, wherein the inlet of the reverse osmosis system is positioned significantly closer to the center of rotation than the concentrate outlet in order to further drive the circulation flow and to continuously support a certain degree of membrane self-cleaning. A rotating body according to one of the above claims, characterized in that the pressure-reduced permeate hits a convex or slightly V-shaped collecting wall and, after being discharged through corresponding permeate channels, passes through a nozzle-like, almost tangentially arranged outlet opening, thereby generating a recoil force that supports the rotation, wherein the permeate outlet can be continuous or pulsed. A reverse osmosis system according to claim 1, characterized in that the energy loss resulting from frictional losses of the rotating float in the liquid-filled basin is additionally utilized. The energy loss leading to a temperature increase within the basin, which is thermally insulated from the environment as effectively as possible, is also utilized.

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