Ultrafiltration seawater desalination equipment and system

Abstract

The invention discloses ultrafiltration seawater desalination equipment and system, and belongs to the technical field of seawater desalination, the equipment comprises: a tank body, the tank body comprises a shell, a first seal head and a second seal head, and the shell is used for defining an accommodating space; a plurality of tubular ultrafiltration membrane elements are arranged in the accommodating space, so that ultrafiltration water supply chambers are formed outside the ultrafiltration membrane elements, and ultrafiltration cavities are formed in the ultrafiltration membrane elements; a water-permeable supporting plate is arranged at one end, facing the first sealing head, of the shell, a plurality of first water-permeable openings are formed in the water-permeable supporting plate, a part of the first water-permeable openings are communicated with the ultrafiltration membrane element so as to supply water into the ultrafiltration cavity, a part of the first water-permeable openings are communicated with the ultrafiltration water supply chamber, and a water-impermeable supporting plate is arranged at the other end of the shell so as to supply water into the ultrafiltration cavity. A plurality of second water permeable ports are formed in the waterproof supporting plate and are communicated with the ultrafiltration membrane elements in a one-to-one correspondence manner. And the compactness and reliability of the equipment body are realized, so that necessary equipment conditions are provided for the simplification of the process flow of the whole system by virtue of the high-pressure potential brought by the tank body.

Description

Technical Field

[0001] This invention belongs to the field of seawater desalination technology, specifically relating to an ultrafiltration seawater desalination device and system. Background Technology

[0002] Seawater desalination technology is one of the important ways to solve the global water shortage problem, especially in offshore operations such as offshore platforms and floating production storage and offloading (FPSO) facilities far from land, where a stable supply of fresh water is crucial for personnel living, equipment operation, and production processes. In these special scenarios with limited space, compact layout, and extremely high requirements for system reliability and ease of maintenance, traditional large-scale and complex land-based seawater desalination systems are difficult to apply directly.

[0003] Ultrafiltration-reverse osmosis (UOS) is currently the mainstream seawater desalination technology. UOS, as the core pretreatment unit for reverse osmosis, removes suspended solids, colloids, microorganisms, and other contaminants from seawater to protect the expensive downstream reverse osmosis membranes. In traditional processes, UOS systems typically employ dozens to hundreds of independent UOS membrane elements, connected in parallel through complex piping networks to form a large membrane module. While this meets treatment requirements, it also introduces significant drawbacks. First, it results in a loosely structured equipment with numerous piping interfaces, occupying a huge area and significantly increasing installation complexity, material costs, and potential leakage risks. Second, the cumbersome piping makes daily maintenance, membrane element inspection, and replacement extremely inconvenient.

[0004] More critically, the pressure resistance of the ultrafiltration membrane itself is a significant factor. Limited by the sealing structure and material strength at the membrane element's ends, traditional ultrafiltration membrane elements typically withstand low internal and external pressure differences (generally operating pressures below 0.35 MPa). To prevent damage to the ultrafiltration membrane during operation or pressure fluctuations, traditional designs necessitate the installation of buffer tanks before and after the ultrafiltration system, along with multi-stage intermediate pumps for segmented pressurization and stabilization. This results in a lengthy process flow, a large number of equipment, high system energy consumption, and further encroaches on valuable space.

[0005] Therefore, there is an urgent need for a seawater desalination equipment that can be highly integrated in structure, simplify pipeline connections, and effectively overcome the pressure limitations of ultrafiltration units. Summary of the Invention

[0006] This invention provides an ultrafiltration seawater desalination device and system. By designing an integrated tank structure with significantly improved pressure resistance, multiple ultrafiltration membrane elements are compactly encapsulated within it. The parallel fixing and flow channel distribution of the membrane elements are achieved using permeable and impermeable support plates. This solves the technical problems of traditional decentralized pipeline ultrafiltration systems, such as loose structure, complex connections, large footprint, low pressure resistance, and the need for buffer tanks and multi-stage pump stations, which result in a lengthy process flow, high energy consumption, inconvenient maintenance, and difficulty in being applied to space-constrained occasions such as offshore platforms.

[0007] The technical solution adopted in this invention is as follows: An ultrafiltration seawater desalination device, comprising: A tank body, the tank body comprising a shell and a first end cap and a second end cap disposed at both ends of the shell, the shell being used to enclose a receiving space; The accommodating space is provided with a plurality of tubular ultrafiltration membrane elements to form an ultrafiltration feed water chamber outside the ultrafiltration membrane elements and an ultrafiltration cavity inside the ultrafiltration membrane elements; A water-permeable support plate is provided at one end of the housing facing the first end cap. The water-permeable support plate is provided with a plurality of first water permeable ports. Some of the first water permeable ports are connected to the ultrafiltration membrane element to supply water to the ultrafiltration chamber, and some of the first water permeable ports are connected to the ultrafiltration water supply chamber. The other end of the shell is provided with a water-impermeable support plate, which is provided with a plurality of second water inlets. The second water inlets are connected to the ultrafiltration membrane elements one by one to discharge the purified seawater.

[0008] The ultrafiltration seawater desalination equipment disclosed in this invention also has the following additional technical features: In operation, the tank is in a vertical position, with the first end cap located at the lower end of the shell. The first end cap is provided with a water inlet, and a pre-filter is provided between the water inlet and the permeable support plate.

[0009] The pre-filter is a plate-shaped structure and is inclined so that the normal of the pre-filter faces the water inlet.

[0010] The first end cap is also provided with a flushing port and a drain port. The flushing port is located between the pre-filter and the permeable support plate, and the drain port is located on the other side of the pre-filter opposite to the flushing port. The upper edge of the water inlet is lower than the upper edge of the flushing port, and the upper edge of the drain outlet is lower than the upper edge of the water inlet.

[0011] The housing is provided with a water supply chamber cleaning inlet and a water supply chamber cleaning outlet that connect to the ultrafiltration water supply chamber. The water supply chamber cleaning inlet and the water supply chamber cleaning outlet are respectively located on both sides of the housing in the radial direction.

[0012] In operation, the tank is in a vertical position, and the water supply chamber cleaning inlet and water supply chamber cleaning outlet are located at opposite ends of the shell in the axial direction. The upper edge of the water supply chamber cleaning inlet is lower than the upper edge of the water supply chamber cleaning outlet.

[0013] When in operation, the tank is in a vertical position, the second end cap is located at the upper end of the shell, and the second end cap is provided with a clean water outlet, an air inlet and a chemical cleaning port; The upper edges of the air inlet and the chemical cleaning port are lower than the upper edge of the purified water outlet, and the air inlet and the chemical cleaning port are respectively located on both sides of the radial direction of the housing.

[0014] This invention provides another ultrafiltration reverse osmosis seawater desalination system. Includes a water intake pump connected in sequence, the ultrafiltration seawater desalination equipment, and a freshwater storage and distribution equipment; The water intake pump is used to supply seawater to the ultrafiltration seawater desalination equipment; The freshwater storage and distribution equipment is used to receive the purified water produced by the ultrafiltration seawater desalination equipment.

[0015] A coarse filter is also connected between the water intake pump and the ultrafiltration seawater desalination equipment. The coarse filter is one or more of the following: sand filter, activated carbon filter, multi-media filter, and self-cleaning filter.

[0016] The ultrafiltration reverse osmosis seawater desalination system also includes: A reverse osmosis high-pressure pump is connected to the purified water outlet of the ultrafiltration seawater desalination equipment to pressurize the ultrafiltration treated influent. A reverse osmosis membrane module is connected to the outlet of the reverse osmosis high-pressure pump; An energy recovery unit, the high-pressure side inlet of which is connected to the high-pressure concentrate outlet of the reverse osmosis membrane module, is used to recover the pressure energy of the high-pressure concentrate and transfer the recovered energy to the inlet side or drive shaft of the reverse osmosis high-pressure pump.

[0017] Due to the adoption of the above technical solution, the beneficial effects achieved by this invention are as follows: 1. In this invention, dozens to hundreds of ultrafiltration membrane elements, which are connected by dispersed pipelines in traditional processes, are integrated and packaged into a unified tank-shaped container, eliminating the large and complex external connection network of the membrane module in traditional systems. This achieves a significant simplification and compactness of the equipment's physical structure, and significantly reduces the overall footprint and volume of the equipment.

[0018] Furthermore, because the membrane elements are built-in and fixed within the tank, their permeate is collected through an integrated impermeable support plate and discharged through a single (or a few) outlets, replacing the independent external piping for each membrane element's permeate end in traditional systems. This drastically reduces the number of external interfaces for the entire ultrafiltration unit. Consequently, it effectively reduces the potential leakage risks associated with numerous pipes, flanges, and joints, while simplifying installation and connection complexity, and improving the reliability and maintainability of the equipment.

[0019] The permeable support plate is equipped with multiple first permeate ports. Some of these first permeate ports are connected to the ultrafiltration membrane element to supply water to the ultrafiltration chamber, while others are connected to the ultrafiltration feed chamber. This ensures consistent pressure inside and outside the ultrafiltration membrane element, preventing damage caused by excessive pressure differential. The pressure borne by the ultrafiltration membrane element is transferred to the tank. As a robust pressure vessel, the tank's pressure-bearing capacity is primarily determined by the mechanical strength of the tank body (shell and end caps), rather than being limited by the pressure-bearing capacity of a single ultrafiltration membrane element (traditionally typically below 0.35 MPa), thus endowing the entire ultrafiltration equipment with the potential for high-pressure operation. This high-pressure capability allows the permeate from the ultrafiltration equipment to directly enter downstream high-pressure stages (such as reverse osmosis high-pressure pumps), providing the possibility and structural guarantee for eliminating the traditional buffer tank and intermediate booster pump located between ultrafiltration and reverse osmosis in the system flow.

[0020] In summary, the system achieves compactness and reliability, and, leveraging the high-pressure potential of the tank, provides the necessary equipment conditions for simplifying the entire system's process flow (eliminating buffer tanks and reducing the number of pumps). It solves core problems such as large space occupation, system complexity, high energy consumption, and unsuitability for offshore platforms. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a cross-sectional schematic diagram of the ultrafiltration seawater desalination device according to one embodiment of the present invention, wherein the arrows in the figure indicate the direction of water flow; Figure 2 This is a top view of the ultrafiltration seawater desalination device according to one embodiment of the present invention at section aa; Figure 3 This is a bottom view of the ultrafiltration seawater desalination device according to one embodiment of the present invention at section aa; Figure 4 This is a schematic diagram of the ultrafiltration reverse osmosis seawater desalination system according to one embodiment of the present invention.

[0022] in, 1. Tank body; 11. Shell; 111. Water supply chamber cleaning inlet; 112. Water supply chamber cleaning outlet; 12. First end cap; 121. Water inlet; 122. Pre-filter; 123. Flushing port; 124. Sewage outlet; 13. Second end cap; 131. Clean water outlet; 132. Air inlet; 133. Chemical cleaning port; 2. Ultrafiltration membrane element; 21. Ultrafiltration feed chamber; 22. Ultrafiltration cavity; 3. Permeable support plate; 31. First permeable inlet; 4. Impermeable support plate; 41. Second water inlet. Detailed Implementation

[0023] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0025] like Figures 1 to 3 As shown, an ultrafiltration seawater desalination device includes: Tank 1, the tank 1 includes a shell 11 and a first end cap 12 and a second end cap 13 disposed at both ends of the shell 11, the shell 11 being used to enclose an accommodating space; The accommodating space is provided with a plurality of tubular ultrafiltration membrane elements 2, so as to form an ultrafiltration water supply chamber 21 outside the ultrafiltration membrane elements 2 and an ultrafiltration cavity 22 inside the ultrafiltration membrane elements 2. A water-permeable support plate 3 is provided at one end of the housing 11 facing the first end cap 12. The water-permeable support plate 3 is provided with a plurality of first water permeable ports 31. Some of the first water permeable ports 31 are connected to the ultrafiltration membrane element 2 to supply water to the ultrafiltration chamber 22, and some of the first water permeable ports 31 are connected to the ultrafiltration water supply chamber 21. The other end of the housing 11 is provided with a water-impermeable support plate 4. The water-impermeable support plate 4 is provided with a plurality of second water inlets 41. The second water inlets 41 are connected to the ultrafiltration membrane element 2 in a one-to-one correspondence to discharge the purified seawater.

[0026] The core objective of this solution is to provide a highly integrated ultrafiltration device to address the inherent drawbacks of traditional seawater desalination pretreatment processes, such as loose equipment layout, large footprint, complex piping, and difficult maintenance caused by the use of decentralized pipelines to connect numerous membrane elements. The aim is to achieve a compact and modular design, laying the foundation for simplifying the entire seawater desalination system process and improving its pressure adaptability.

[0027] The device uses a tank 1 as its basic framework. The tank 1 is formed by a shell 11 and a first end cap 12 and a second end cap 13 that seal its two ends, creating a sealed containment space. This design transforms the traditional ultrafiltration membrane module from an open system connected by externally distributed pipelines into a complete, integrated pressure vessel.

[0028] It should be noted that there are no restrictions on the cross-sectional shape of the shell 11. It can be a circular cross-section, that is, the shell 11 is a cylinder. Similarly, the cross-sectional shape can also be square or rectangular.

[0029] Within the containment space, multiple tubular ultrafiltration membrane elements 2 are disposed. These membrane elements are not independently externally connected, but are built-in and fixed within the tank 1. The parallel arrangement of these membrane elements naturally divides the tank 1 into two key hydraulic spaces: a common ultrafiltration feed chamber 21 is formed in the annular area outside the multiple membrane elements; and an ultrafiltration chamber 22 is formed in the internal tubular cavity of each membrane element.

[0030] Multiple ultrafiltration membrane elements 2 are housed within a containment space. They can extend parallel to the axis of the containment space to reduce flow resistance; similarly, they can also extend spirally within the containment space to increase thread length.

[0031] By integrating dozens or even hundreds of independent membrane elements into a single tank, the complex and bulky external connection networks and supports of traditional processes are completely eliminated. The equipment exists as an integrated, modular unit, reducing its footprint and volume, which is suitable for applications such as offshore platforms (FPSOs) with extremely high space utilization requirements.

[0032] Furthermore, the drastically reduced number of external pipes, flanges, and joints significantly decreases the potential leakage points of the entire system, enhancing the reliability of equipment operation. Simultaneously, the modular tank design simplifies and expedites the transportation, installation, and potential future replacement or maintenance of the entire equipment.

[0033] The permeable support plate 3 (located on the side of the first end cap 12) is provided with multiple first water permeates 31. These water permeates are divided into two functional groups. One group is connected to the end of the ultrafiltration membrane element 2 for directly supplying water to the ultrafiltration chamber 22 (inside the membrane). The other group is connected to the ultrafiltration feed chamber 21 (outside the membrane). This means that after the feed water passes through this plate, it is simultaneously and at the same pressure distributed to both the inside and outside of the membrane element.

[0034] This design ensures that the static pressure on both the inner and outer sides of the ultrafiltration membrane element 2 (i.e., the ultrafiltration feed chamber 21 and the ultrafiltration cavity 22) is essentially the same during operation, thereby effectively eliminating the huge net pressure difference acting on the membrane tube wall and protecting the membrane element itself, which has a low pressure resistance. The tank 1 can be designed to withstand higher pressures (e.g., 1.6 MPa or higher) depending on system requirements. This ensures that its permeate has sufficient pressure to directly enter downstream high-pressure stages (such as the reverse osmosis high-pressure pump).

[0035] Furthermore, the impermeable support plate 4 (located on the side of the second end cap 13) is provided with multiple second water perforations 41, which are connected to the other end of each ultrafiltration membrane element 2. It is understood that the plate itself is impermeable, and its water perforations serve only as channels to collect the purified water (i.e., permeate) produced by all ultrafiltration membrane elements 2. The purified water, after membrane filtration, flows out from each ultrafiltration chamber 22, passes through the corresponding second water perforation 41, collects in the space behind the plate (usually located inside the second end cap 13), and is finally discharged through a unified purified water outlet 131.

[0036] As a preferred embodiment of the present invention, such as Figure 1 As shown, in the working state, the tank 1 is in a vertical position, and the first end cap 12 is located at the lower end of the shell 11. The first end cap 12 is provided with a water inlet 121, and a pre-filter 122 is provided between the water inlet 121 and the water-permeable support plate 3.

[0037] The core objective of this embodiment is to solve specific engineering problems encountered in actual operation of the equipment, such as solid particle deposition, pretreatment efficiency, space adaptability and maintenance convenience, by setting the tank 1 to a vertical working state and optimizing the water inlet and pretreatment structure at its bottom (first end cap 12), thereby further improving the operational stability and environmental adaptability of the integrated ultrafiltration equipment.

[0038] When the equipment is in operation, the entire tank 1 is in a vertical position. The first end cap 12 is located at the lower end of the shell 11, serving as the bottom, and the second end cap 13 is located at the upper end of the shell 11, serving as the top. The equipment's base support ensures that the tank 1 maintains a stable vertical posture after installation.

[0039] An inlet 121 is provided on the first end cap 12 at the lower end. This means that the raw water (pretreated seawater) enters from the bottom of the tank 1. A pre-filter 122 is added between the inlet 121 and the internal permeable support plate 3. This pre-filter 122 constitutes the last physical barrier before the raw water enters the membrane system.

[0040] Raw water flows into the first end cap 12 chamber from the bottom side inlet 121 → it first impacts and passes through the pre-filter 122, intercepting any larger particles or suspended solids that may remain in the water → the pre-filtered, relatively clean water flows upward and reaches the permeable support plate 3, and is then distributed to the membrane element for ultrafiltration.

[0041] The vertical structure offers advantages such as small footprint, low center of gravity, and good stability, making it particularly suitable for compact deployment on space-constrained offshore platforms (FPSOs). Furthermore, the vertical structure, combined with bottom inlet, allows water to flow upwards within the tank. Denser particles or flocs that are not completely intercepted by the pre-filter 122 are subject to gravity as they flow upwards. This helps these impurities settle naturally in areas with lower upward flow velocities (such as the first end cap 12 chamber or the bottom of the membrane shell), rather than being entirely carried to the membrane surface by the water flow. This effectively slows down the accumulation rate of suspended solids on the membrane element, reduces the risk of membrane fouling, and extends chemical cleaning cycles.

[0042] Meanwhile, all impurities that may settle and the dirt discharged during backwashing naturally collect in the bottom first end cap 12. This makes the design of the drain pipe more direct and efficient. Simply set a drain port 124 at the bottom or lowest point of the first end cap 12 to completely empty the sediment by gravity, resulting in better cleaning.

[0043] Furthermore, integrating the pre-filter 122 directly after the inlet 121 and before the permeable support plate 3 is equivalent to setting up a front-line defense inside the high-pressure tank 1. This effectively intercepts relatively large mechanical impurities that leak from the upstream pretreatment system, preventing these impurities from directly impacting, clogging, or scratching the precision permeable ports on the permeable support plate 3 and the ends of the ultrafiltration membrane element 2, thus protecting the core ultrafiltration membrane.

[0044] As a preferred embodiment of this implementation, such as Figure 1 As shown, the pre-filter 122 has a plate-like structure and is inclined so that the normal of the pre-filter 122 faces the water inlet 121.

[0045] The core objective of this embodiment is to optimize the physical form and spatial orientation of the pre-filter 122 to solve problems such as impact, clogging and flow field distribution of the pre-filter 122 by the influent, thereby improving the stability and durability of the pre-filtration efficiency and indirectly protecting the downstream core membrane element.

[0046] The pre-filter 122 is specifically embodied as a plate-shaped filter unit. This can be a sieve plate, a perforated plate, or a plate structure with a specific filtration precision (such as pore size or mesh count) stretched over a frame. The plate-shaped member is designed to completely cover the cross-section of the necessary passage for water flow from the inlet 121 to the permeable support plate 3, as a single interception surface.

[0047] The plate-shaped pre-filter 122 is not installed vertically or horizontally, but rather at an angle relative to the horizontal plane or the axis of the tank 1. The key requirement for its installation angle is that the normal direction of the plate plane (i.e., the direction perpendicular to the plate surface) should be aligned with or approximately aligned with the inflow direction of the inlet 121. By designing corresponding support or slot structures inside the first end cap 12, the pre-filter plate is fixed at the preset inclination angle, ensuring that the centerline of the inlet 121 is substantially coincident with the normal direction of the plate surface.

[0048] When water flows out from the inlet 121 at a high velocity, if it impacts a vertical plane, a high-pressure zone is easily formed at the center of the impact point, while eddies or low-pressure zones may be generated around it. This results in an extremely uneven distribution of water flow and impurities through the filter surface, and local areas are prone to rapid blockage.

[0049] Setting the filter plate at an angle with its normal aligned with the inlet 121 means that the water flow is impacting (or nearly impacting) the plate surface. This arrangement allows the water flow impact force to be more evenly distributed across the entire plate surface, promoting a more uniform flow of water and impurities across the entire effective area of ​​the filter plate. This avoids premature local clogging, thereby improving the overall dirt-holding capacity and efficiency of the pre-filter 122.

[0050] Furthermore, the inclined plate surface provides a downward tendency for trapped solid particles to slide. After the particles settle on the plate surface, under the combined action of their own gravity along the plate surface and the shear force of the water flow, they are more likely to slide and converge along the inclined surface to the lower side, rather than being firmly attached to the area directly facing the water flow. This helps to slow down the clogging rate of the filter plate pores, achieving a certain degree of self-cleaning or self-sludge removal effect, and extending the interval between manual cleaning or backwashing.

[0051] Furthermore, the positive impact-uniform diffusion flow pattern, compared to the turbulent reflected flow generated by impacting a vertical plane, can create a smoother and more orderly upward water flow. This smooth water flow, after pre-filtration, can reach and pass through the permeable support plate 3 more evenly, providing a more balanced feed water distribution for the subsequent ultrafiltration membrane element 2. This avoids the problem of some membrane elements being overloaded and prematurely fouled due to uneven feed water distribution, which helps protect the ultrafiltration membrane element 2 and extends its service life and cleaning cycle.

[0052] As another embodiment of this implementation, such as Figure 1 As shown, the first end cap 12 is also provided with a flushing port 123 and a drain port 124. The flushing port 123 is disposed between the pre-filter 122 and the permeable support plate 3, and the drain port 124 is located on the other side of the pre-filter 122 opposite to the flushing port 123. The upper edge of the water inlet 121 is lower than the upper edge of the flushing port 123, and the upper edge of the drain port 124 is lower than the upper edge of the water inlet 121.

[0053] The core objective of this embodiment is to integrate a set of functional interfaces dedicated to maintenance, cleaning, and impurity discharge on the first end cap 12, and to solve problems such as low cleaning efficiency, incomplete sewage discharge, and cumbersome operation during equipment operation and maintenance by precisely defining their relative positional relationships. This enables efficient and convenient maintenance of the core area of ​​the equipment and ensures its long-term stable operation.

[0054] A flushing port 123 is formed on the first end cap 12, located in the chamber area between the pre-filter 122 and the permeable support plate 3. This means that the flushing medium (such as water or a water-air mixture) can be directly injected into this area. Positioning the flushing port 123 after the pre-filter 122 and before the permeable support plate 3 allows the injected flushing water or airflow to directly flush the back (outlet side) of the pre-filter 122 and the water-facing surface of the permeable support plate 3, which is precisely the area where impurities are most likely to adhere and clog.

[0055] The drain outlet 124 is also located on the first end cap 12, on the other side of the pre-filter 122 (i.e., on both sides of the pre-filter 122, which is separated from the flushing outlet 123). This usually refers to the side of the pre-filter 122 closer to the inlet 121, i.e., the chamber area where the inlet 121 is located.

[0056] The drain outlet 124 is located before the pre-filter 122 (on the water inlet side) and on the opposite side of the flushing outlet 123, so that the dirt washed off from the pre-filter 122 can be carried by the water flow, bypass the edge of the pre-filter 122 (or through some of its pores) and enter the water inlet side chamber, and finally be discharged from the lowest drain outlet 124.

[0057] On the shell 11 of the first end cap 12, according to the position of the internal components (pre-filter 122), holes are opened on the chamber walls on both sides and pipes are connected to form a flushing port 123 and a drain port 124 with independent functions.

[0058] The upper edges of the three openings follow a strict vertical height order: upper edge of drain port 124 < upper edge of inlet port 121 < upper edge of flushing port 123. When designing and manufacturing the first end cap 12, the center position of each pipe opening is determined according to this height order to ensure that the aforementioned height relationship is met when the equipment is in a vertical working state.

[0059] The lowest position of the drain outlet 124 ensures that after the pump stops or the pressure is released, the accumulated liquid and settled solids in the entire first head 12 chamber (including the water inlet side and the back side of the pre-filter 122) can be discharged by gravity from the drain outlet 124 at the lowest point, without any residual dead corners.

[0060] Furthermore, the inlet 121 is higher than the outlet 124, ensuring that the inlet 121 maintains a reasonable immersion depth during normal operation and preventing air from being sucked in. During drainage, as the liquid level drops, the inlet 121 will emerge from the water surface before the outlet 124, preventing siphoning, facilitating air entry, and promoting the smooth drainage of accumulated liquid.

[0061] The flushing port 123 is positioned at the highest point, ensuring that the flushing medium can be injected from a higher position during the flushing operation. This helps to create sufficient agitation and coverage within the chamber and prevents the flushing water from escaping directly from the lower port before it has served its purpose.

[0062] The flushing port 123 and the drain port 124 are respectively located on both sides of the pre-filter 122, effectively dividing the interior of the first end cap 12 into two functionally independent sub-regions: a water inlet / drainage chamber and a flushing / buffering chamber. During normal filtration, the water inlet chamber and the flushing chamber are connected through the pre-filter 122, but the flushing port 123 is closed to avoid unnecessary flow path interference. During flushing, a certain pressure difference or flow direction can be formed between the two chambers, driving the directional movement of contaminants.

[0063] As a preferred embodiment of the present invention, such as Figure 1 As shown, the housing 11 is provided with a water supply chamber cleaning inlet 111 and a water supply chamber cleaning outlet 112 that communicate with the ultrafiltration water supply chamber 21. The water supply chamber cleaning inlet 111 and the water supply chamber cleaning outlet 112 are respectively located on both sides of the housing 11 in the radial direction.

[0064] The core objective of this embodiment is to provide an efficient and thorough dedicated cleaning pathway for the ultrafiltration feed water chamber 21, so as to solve the problem of contaminant accumulation on the outside of the ultrafiltration membrane element 2 during long-term operation and the difficulty in effective cleaning, thereby ensuring the long-term stability of membrane separation performance and simplifying equipment maintenance.

[0065] Two independent interfaces are directly provided on the housing 11 of the device, namely the water supply chamber cleaning inlet 111 and the water supply chamber cleaning outlet 112. These two interfaces are directly connected to the ultrafiltration water supply chamber 21 (i.e., the annular common space outside the multiple ultrafiltration membrane elements 2) through the wall of the housing 11.

[0066] When processing the shell 11, two flanged or threaded pipes are welded or machined on the wall of its cylindrical body, corresponding to the axial height position of the ultrafiltration water supply chamber 21, to serve as the inlet and outlet of the cleaning medium.

[0067] The water supply chamber cleaning inlet 111 and water supply chamber cleaning outlet 112 are designed to be located on opposite sides of the housing 11 in the radial direction. This typically means that they are arranged approximately 180 degrees symmetrically (or in relative positions within allowable deviations) in the circumferential direction of the housing 11. When determining the location of the openings on the housing 11, an imaginary diameter line passing through the axis of the housing 11 is selected, and the cleaning inlet and cleaning outlet are respectively located near the two ends of this diameter line.

[0068] The fundamental purpose of placing the cleaning inlet and outlet on opposite radial sides is to ensure that when the cleaning fluid (such as chemical cleaning agent or clean water) is injected into the ultrafiltration feed chamber 21 from one inlet, it can traverse the entire cross-section of the annular chamber laterally and flow out from the outlet on the other side. This through-flow pattern establishes a cleaning flow field with a clear direction and a long path within the feed chamber. Compared to the potential short-circuit flow or eddy current areas that might result from setting the inlet and outlet on the same side or near the housing 11, this forces the cleaning fluid to contact the outer surfaces of more membrane elements and flush a wider area within the chamber, greatly reducing cleaning dead zones. This achieves a more comprehensive and thorough cleaning of the ultrafiltration feed chamber 21 and the outer walls of all membrane elements.

[0069] In a preferred embodiment of this implementation, the tank 1 is in a vertical position during operation. The water supply chamber cleaning inlet 111 and the water supply chamber cleaning outlet 112 are respectively located at the two ends of the shell 11 in the axial direction. The upper edge of the water supply chamber cleaning inlet 111 is lower than the upper edge of the water supply chamber cleaning outlet 112.

[0070] The core objective of this embodiment is to optimize the spatial layout and flow direction of the dedicated cleaning passage in the water supply chamber to solve problems such as uneven distribution of cleaning fluid, gas retention, and incomplete discharge that may occur when performing chemical cleaning or enhanced backwashing in the vertical tank 1, thereby achieving a more efficient and thorough online cleaning effect and simplifying the operation process.

[0071] With the tank 1 in a vertical working state, the water supply chamber cleaning inlet 111 and the water supply chamber cleaning outlet 112 are respectively located at both ends of the shell 11 in the axial direction. This means that one cleaning port is located in the area near the lower end (first end cap 12 side) of the shell 11, and the other is located in the area near the upper end (second end cap 13 side) of the shell 11.

[0072] When designing and manufacturing the cylindrical shell 11, an interface is opened near the lower end of the cylinder as a cleaning inlet (or outlet), and another interface is opened near the upper end as a corresponding outlet (or inlet), with the two being significantly separated by an axial distance.

[0073] By positioning the cleaning inlet and outlet at opposite ends of the axial direction (one at the bottom and one at the top), the cleaning fluid, when injected from the bottom inlet, naturally flows upwards and eventually exits from the top outlet. This bottom-in, top-out axial flow field forces the cleaning fluid to flow upwards across most of the axial height of the ultrafiltration feed chamber 21. Compared to radial through-flow, which primarily acts on a single cross-section, this axial flow achieves sequential flushing of the entire feed chamber's three-dimensional space (from bottom to top), ensuring that the outer surfaces of all axially arranged membrane elements are effectively contacted and cleaned by the cleaning fluid, eliminating cleaning dead zones along the axial height.

[0074] Specifically, the upper edge of the water supply chamber cleaning inlet 111 is lower than the upper edge of the water supply chamber cleaning outlet 112. When the equipment is upright, the inlet is lower than the outlet in vertical height. This height relationship must be strictly followed when determining the specific opening height of the two axial interfaces for positioning and machining.

[0075] Before cleaning begins, air may be present in the water supply chamber; during the cleaning process, certain chemical reactions may also generate gases. By adopting a low inlet and high outlet layout, the cleaning fluid enters from the lower level, naturally driving air or reaction gases upwards, and finally smoothly exiting from the highest outlet, effectively avoiding airlock. Airlock would prevent the cleaning fluid from filling the water supply chamber, leading to incomplete cleaning.

[0076] Lighter suspended contaminants shed during the cleaning process are carried to the top outlet by the rising current and buoyancy, preventing them from settling again in the water supply chamber.

[0077] It should be noted that there is no limit to the number of water supply chamber cleaning inlets 111 and outlets 112. One water supply chamber cleaning inlet 111 and / or one water supply chamber cleaning outlet 112 can be provided; similarly, multiple water supply chamber cleaning inlets 111 and multiple water supply chamber cleaning outlets 112 can be provided. The water supply chamber cleaning inlets 111 and outlets 112 can be arranged according to the positions described in the above embodiments.

[0078] As a preferred embodiment of the present invention, such as Figure 1 As shown, in the working state, the tank 1 is in a vertical position, the second end cap 13 is located at the upper end of the shell 11, and the second end cap 13 is provided with a clean water outlet 131, an air inlet 132 and a chemical cleaning outlet 133. The upper edges of the air inlet 132 and the chemical cleaning port 133 are lower than the upper edge of the purified water outlet 131. The air inlet 132 and the chemical cleaning port 133 are respectively located on both sides of the housing 11 in the radial direction.

[0079] The core objective of this embodiment is to optimize the functional integration and spatial layout of the top of the equipment (second end cap 13). By precisely defining the relative positions and height relationships of different functional interfaces such as water production, air intake, and chemical cleaning, the engineering problems of the equipment in water production collection, membrane system maintenance (air scrubbing, chemical cleaning), and prevention of cross-contamination are solved, thereby ensuring water production quality and improving the effectiveness and convenience of maintenance operations.

[0080] Three core functional interfaces are centrally located on the second end cap 13 at the upper end of the shell 11: a clean water outlet 131, an air inlet 132, and a chemical cleaning inlet 133. Based on the functional requirements of each interface, holes are made and pipes are welded onto the shell 11 of the second end cap 13, and corresponding valves and pipes are configured to achieve connection with external systems.

[0081] The upper edges of the air inlet 132 and the chemical cleaning port 133 must be lower than the upper edge of the clean water outlet 131. During design and manufacturing, the center line of the opening of the clean water outlet 131 is set at the highest relative position of the second end cap 13, while the center lines of the air inlet 132 and the chemical cleaning port 133 are set at a lower position to ensure the aforementioned height difference is achieved after the equipment is installed vertically.

[0082] Setting the purified water outlet 131 at the highest point is a key design feature to ensure the reliability of the water production system. During normal operation, the freshwater collected from the ultrafiltration membrane chamber into the second end cap 13 may contain trace amounts of dissolved gases or occasional entrained air bubbles. Because the purified water outlet 131 is located at the highest point, these gases can naturally accumulate at the top and be discharged through the outlet pipe (or through a designed vent valve) without accumulating inside the end cap and forming an air blockage. This ensures that the water production line is always filled with liquid, the flow rate is stable, and gas is prevented from entering the downstream freshwater storage system.

[0083] During air scouring maintenance, compressed air is injected through the lower-positioned air inlet 132. Since air density is much lower than water, it rises rapidly immediately after injection, violently agitating the water surrounding the ultrafiltration membrane element 2 during its ascent. This creates effective shear scouring on the membrane fiber surface, causing adhering contaminants to detach. This design is often combined with bottom water inlet or flushing to form an upward air-water flow, resulting in better cleaning performance.

[0084] When chemical cleaning of the membrane element interior (ultrafiltration chamber 22) is required, the cleaning solution is injected from the lower chemical cleaning port 133 (at which time the purified water outlet 131 may be closed or as part of the loop), ensuring that the cleaning solution fills the entire membrane chamber from bottom to top.

[0085] The air inlet 132 and the chemical cleaning port 133 are located on opposite sides of the housing 11 in the radial direction. They are generally understood to be arranged approximately 180 degrees opposite each other on the circumference of the head. When determining the circumferential positions of the air inlet 132 and the chemical cleaning port 133, a diameter line passing through the center of the head is selected, and the two ports are arranged near both ends of this line.

[0086] By radially separating the chemical cleaning port 133 and the air inlet 132 on opposite sides, the two different maintenance functions are physically separated. This avoids incorrect pipe connections and facilitates clear labeling of interfaces for different purposes on the equipment. Both ports are located below the purified water outlet 131, ensuring that during operation, the residual liquid level in both the chemical cleaning and air inlet lines remains below the purified water outlet 131, completely eliminating the possibility of maintenance media accidentally entering the product water system and ensuring the safety of the product water quality.

[0087] This invention also provides an ultrafiltration reverse osmosis seawater desalination system, such as... Figure 4 As shown, Includes a water intake pump connected in sequence, the ultrafiltration seawater desalination equipment, and a freshwater storage and distribution equipment; The water intake pump is used to supply seawater to the ultrafiltration seawater desalination equipment; The freshwater storage and distribution equipment is used to receive the purified water produced by the ultrafiltration seawater desalination equipment.

[0088] It should be noted that there is no limit to the number of ultrafiltration seawater desalination devices. One ultrafiltration seawater desalination device can be connected to form an ultrafiltration reverse osmosis seawater desalination system; similarly, multiple ultrafiltration seawater desalination devices can be connected in parallel to form an ultrafiltration reverse osmosis seawater desalination system.

[0089] This system can achieve any of the effects described in the corresponding embodiments of the ultrafiltration seawater desalination equipment, which will not be elaborated here.

[0090] As a preferred embodiment of the present invention, such as Figure 4As shown, a coarse filter is also connected between the water intake pump and the ultrafiltration seawater desalination equipment. The coarse filter is one or more of the following: sand filter, activated carbon filter, multi-media filter, and self-cleaning filter.

[0091] The core objective of this implementation is to establish a reliable and diverse pretreatment barrier before seawater enters the core tank-type ultrafiltration reverse osmosis equipment. This addresses the potential pollution, blockage, and damage to the subsequent core membrane system caused by impurities such as suspended solids, large particles, some colloids, and organic matter in seawater, thereby ensuring the long-term stable operation of the core equipment and reducing its maintenance frequency and intensity.

[0092] The coarse filter is installed in the process flow between the water intake pump and the ultrafiltration seawater desalination equipment. The connection relationship is as follows: the water intake pump draws seawater → the seawater flows through the coarse filter → the pre-filtered seawater enters the subsequent tank-type ultrafiltration equipment.

[0093] The outlet of the water intake pump is connected to the inlet of the coarse filter via a pipeline, and then the outlet of the coarse filter is connected to the inlet of the ultrafiltration equipment, thus integrating the pretreatment unit in series into the main path of the entire seawater desalination system.

[0094] The coarse filter is one or more of the following: sand filter, activated carbon filter, multi-media filter, and self-cleaning filter. This indicates that these mature and common filtration technologies can be flexibly selected or combined according to the raw seawater quality, treatment objectives, and economic considerations.

[0095] Specifically, sand filters use quartz sand and other similar media to trap suspended solids through the pores between particles. Activated carbon filters use activated carbon media, primarily adsorbing organic matter, residual chlorine, and some odors. Multi-media filters use two or more media of different densities and particle sizes (such as anthracite and quartz sand) layered together to achieve more efficient gradient filtration. Self-cleaning filters are equipped with automatic cleaning mechanisms (such as brushing and backwashing) that can automatically remove impurities trapped in the filter screen without shutting down the system.

[0096] For highly turbid seawater, sand filters or multi-media filters can be used for efficient solid-liquid separation. For seawater with high levels of organic pollutants or residual chlorine, activated carbon filters can be used or additional filters can be added for adsorption. For scenarios with high requirements for automated operation and maintenance (such as unmanned platforms), self-cleaning filters can be used to reduce manual intervention.

[0097] Seawater has a complex composition, containing a large amount of mechanical impurities such as silt, algae, and shell fragments. The coarse filter, as the first physical barrier, effectively removes these larger suspended solids and particulate matter. This significantly reduces the load on subsequent tank-type ultrafiltration systems (especially their built-in pre-filter element 122 and ultrafiltration membrane element 2), preventing large particles from directly impacting, clogging, or scratching the delicate membrane surface. It is an indispensable step in protecting core, expensive membrane assets, directly contributing to extending the service life and cleaning cycle of ultrafiltration and reverse osmosis membranes.

[0098] As a preferred embodiment of the present invention, such as Figure 4 As shown, the ultrafiltration reverse osmosis seawater desalination system further includes: A reverse osmosis high-pressure pump is connected to the purified water outlet 131 of the ultrafiltration seawater desalination equipment to pressurize the ultrafiltration treated influent. A reverse osmosis membrane module is connected to the outlet of the reverse osmosis high-pressure pump; An energy recovery unit, the high-pressure side inlet of which is connected to the high-pressure concentrate outlet of the reverse osmosis membrane module, is used to recover the pressure energy of the high-pressure concentrate and transfer the recovered energy to the inlet side or drive shaft of the reverse osmosis high-pressure pump.

[0099] The core objective of this embodiment is to integrate a high-efficiency and energy-saving reverse osmosis desalination core unit after the compact ultrafiltration pretreatment system, and to solve the inherent high energy consumption problem of the reverse osmosis process through energy recovery technology, thereby constructing a complete, efficient and economical seawater desalination system from pretreatment to desalination and then to energy recovery.

[0100] The reverse osmosis high-pressure pump is directly connected downstream of the purified water outlet 131 of the ultrafiltration seawater desalination equipment. Its core function is to provide the high pressure (typically 5.5-8.0 MPa) required for reverse osmosis desalination to the purified feed water that has already undergone ultrafiltration. The ultrafiltration permeate is directly fed into the suction end of the reverse osmosis high-pressure pump through pipelines, and discharged after being pressurized by the pump.

[0101] The inlet 121 of the reverse osmosis membrane module is connected to the outlet of the reverse osmosis high-pressure pump to receive high-pressure feed water. When the high-pressure feed water enters the reverse osmosis membrane module, under pressure, some water molecules permeate through the membrane to form fresh water (product water), while most of the salt and a small amount of water are concentrated and discharged from the dedicated outlet of the membrane module as "high-pressure concentrate" which still has a high pressure.

[0102] The energy recovery component (such as a piston-type pressure exchanger or a turbine-type energy recovery device) has its high-pressure side inlet connected to the high-pressure concentrate outlet of the reverse osmosis membrane module, and is used to receive and recover the pressure energy contained in the high-pressure concentrate. Its function is to transfer the recovered pressure energy to the inlet side or drive shaft of the reverse osmosis high-pressure pump.

[0103] The energy recovery unit directly transfers the pressure energy of the high-pressure concentrate to a portion of the low-pressure feed water (from ultrafiltration permeate), significantly increasing its pressure. This pre-pressurized feed water is then mixed with the rest of the feed water before entering the high-pressure pump. This directly reduces the pressure head required by the high-pressure pump.

[0104] The energy recovery unit converts the pressure energy of the high-pressure concentrate into mechanical shaft work, which is directly connected to and assists in driving the shaft of the reverse osmosis high-pressure pump, thus directly sharing the driving load of the motor.

[0105] The main cost of reverse osmosis desalination stems from electricity consumption, with the high-pressure pump being the largest energy consumer. Integrating a highly efficient energy recovery device can recover the pressure energy from the high-pressure concentrate. This reduces the energy consumption per ton of water for the entire system. This improves economic viability for offshore platforms (FPSOs) and remote islands where energy costs are high and power supply is limited.

[0106] The introduction of energy recovery technology allows for the use of smaller-capacity reverse osmosis high-pressure pumps and motors while achieving the same water production rate. This not only reduces equipment procurement costs but also further reduces the size and weight of the high-pressure pump unit. It enhances the advantages of the entire system's high integration, small footprint, and light weight, making it particularly suitable for offshore platforms with limited space and load capacity.

[0107] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0108] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0109] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An ultrafiltration seawater desalination device, characterized in that, include: A tank body, the tank body comprising a shell and a first end cap and a second end cap disposed at both ends of the shell, the shell being used to enclose a receiving space; The accommodating space is provided with a plurality of tubular ultrafiltration membrane elements to form an ultrafiltration feed water chamber outside the ultrafiltration membrane elements and an ultrafiltration cavity inside the ultrafiltration membrane elements; A water-permeable support plate is provided at one end of the housing facing the first end cap. The water-permeable support plate is provided with a plurality of first water permeable ports. Some of the first water permeable ports are connected to the ultrafiltration membrane element to supply water to the ultrafiltration chamber, and some of the first water permeable ports are connected to the ultrafiltration water supply chamber. The other end of the shell is provided with a water-impermeable support plate, which is provided with a plurality of second water inlets. The second water inlets are connected to the ultrafiltration membrane elements one by one to discharge the purified seawater.

2. The ultrafiltration seawater desalination equipment according to claim 1, characterized in that, In operation, the tank is in a vertical position, with the first end cap located at the lower end of the shell. The first end cap is provided with a water inlet, and a pre-filter is provided between the water inlet and the permeable support plate.

3. The ultrafiltration seawater desalination equipment according to claim 2, characterized in that, The pre-filter is a plate-shaped structure and is inclined so that the normal of the pre-filter faces the water inlet.

4. The ultrafiltration seawater desalination equipment according to claim 2, characterized in that, The first end cap is also provided with a flushing port and a drain port. The flushing port is located between the pre-filter and the permeable support plate, and the drain port is located on the other side of the pre-filter opposite to the flushing port. The upper edge of the water inlet is lower than the upper edge of the flushing port, and the upper edge of the drain outlet is lower than the upper edge of the water inlet.

5. The ultrafiltration seawater desalination equipment according to claim 1, characterized in that, The housing is provided with a water supply chamber cleaning inlet and a water supply chamber cleaning outlet that connect to the ultrafiltration water supply chamber. The water supply chamber cleaning inlet and the water supply chamber cleaning outlet are respectively located on both sides of the housing in the radial direction.

6. The ultrafiltration seawater desalination equipment according to claim 5, characterized in that, In operation, the tank is in a vertical position, and the water supply chamber cleaning inlet and water supply chamber cleaning outlet are located at opposite ends of the shell in the axial direction. The upper edge of the water supply chamber cleaning inlet is lower than the upper edge of the water supply chamber cleaning outlet.

7. The ultrafiltration seawater desalination equipment according to claim 1, characterized in that, When in operation, the tank is in a vertical position, the second end cap is located at the upper end of the shell, and the second end cap is provided with a clean water outlet, an air inlet and a chemical cleaning port; The upper edges of the air inlet and the chemical cleaning port are lower than the upper edge of the purified water outlet, and the air inlet and the chemical cleaning port are respectively located on both sides of the radial direction of the housing.

8. An ultrafiltration reverse osmosis seawater desalination system, characterized in that, Includes water intake pumps connected in sequence, the ultrafiltration seawater desalination equipment as described in any one of claims 1 to 7, and freshwater storage and distribution equipment; The water intake pump is used to supply seawater to the ultrafiltration seawater desalination equipment; The freshwater storage and distribution equipment is used to receive the purified water produced by the ultrafiltration seawater desalination equipment.

9. The ultrafiltration reverse osmosis seawater desalination system according to claim 8, characterized in that, A coarse filter is also connected between the water intake pump and the ultrafiltration seawater desalination equipment. The coarse filter is one or more of the following: sand filter, activated carbon filter, multi-media filter, and self-cleaning filter.

10. The ultrafiltration reverse osmosis seawater desalination system according to claim 8, characterized in that, Also includes: A reverse osmosis high-pressure pump is connected to the purified water outlet of the ultrafiltration seawater desalination equipment to pressurize the ultrafiltration treated influent. A reverse osmosis membrane module is connected to the outlet of the reverse osmosis high-pressure pump; An energy recovery unit, the high-pressure side inlet of which is connected to the high-pressure concentrate outlet of the reverse osmosis membrane module, is used to recover the pressure energy of the high-pressure concentrate and transfer the recovered energy to the inlet side or drive shaft of the reverse osmosis high-pressure pump.

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