Reverse osmosis membrane assembly

Abstract

The utility model discloses a reverse osmosis membrane assembly which comprises a reverse osmosis core and sealing covers arranged at the two ends of the reverse osmosis core in a sealing manner, the reverse osmosis core comprises a middle inner membrane supporting layer as well as two groups of micro-filtration membranes and two groups of ultra-filtration membranes which wrap the outer side of the inner membrane supporting layer, a laminated pre-filtration layer is arranged between the micro-filtration membranes and the ultra-filtration membranes wrapping the inner membrane supporting layer, a PA reverse osmosis membrane wraps the rear parts of the micro-filtration membranes and the ultra-filtration membranes, and a separation net is arranged behind the PA reverse osmosis membrane; due to the synergistic effect of the multiple layers of membranes, the system can treat a more complex and worse seawater environment, and the stability and reliability of the effluent quality are ensured; due to the design of the laminated pre-filtering layer and the separation net, pollutants are effectively prevented from being in direct contact with the membrane holes and blocking the membrane holes, and the stability of the membrane assembly is further enhanced. Due to the introduction of the automatic backwashing device, the automatic backwashing device can be automatically started at regular intervals or according to a water quality monitoring result, the pre-filter is subjected to backwashing, the service life of the pre-filter is prolonged, and the maintenance cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to reverse osmosis membrane module technical field, concretely is a kind of reverse osmosis membrane module and its operating method. BACKGROUND

[0002] With the increasingly serious global water resource shortage problem, seawater desalination technology, as one of the important means to solve water resource crisis, has received extensive attention and research. Traditional seawater desalination methods include distillation method, electrodialysis method, etc., but these methods often have problems such as high energy consumption, complex equipment, high maintenance cost, etc. Therefore, developing efficient, energy-saving and environmentally friendly seawater desalination technology has become a research hotspot.

[0003] In the seawater desalination process, reverse osmosis technology is widely used due to its high efficiency, energy saving and easy operation. However, traditional reverse osmosis membrane modules often face problems such as membrane fouling, flux decline, and rejection performance decline when treating seawater, which seriously affects the efficiency and water quality of seawater desalination. Therefore, improving the anti-fouling property, stability and rejection performance of reverse osmosis membrane modules has become the key to improving the level of seawater desalination technology.

[0004] Existing reverse osmosis membrane modules usually include single or multi-layer membrane structures, but these membrane structures have deficiencies in removing suspended particles, bacteria, large particulate organic matter, small molecule organic matter, oil, heavy metal ions, etc. in seawater. At the same time, traditional reverse osmosis membrane materials often have unstable membrane performance and are prone to fouling during preparation. SUMMARY

[0005] The technical problem solved by the utility model is to overcome the defects mentioned in the background art and provide a reverse osmosis membrane module.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a reverse osmosis membrane module, comprising a reverse osmosis core and a cover sealingly installed at both ends of the reverse osmosis core; the reverse osmosis core comprises an inner membrane support layer in the middle and two groups of microfiltration membranes and two groups of ultrafiltration membranes wrapped outside the inner membrane support layer; a laminated pre-filter layer is arranged between the microfiltration membranes and the ultrafiltration membranes wrapped around the inner membrane support layer; a PA reverse osmosis membrane is wrapped behind the microfiltration membranes and the ultrafiltration membranes, and a screen is arranged behind the PA reverse osmosis membrane, an activated carbon layer is arranged outside the screen, and the activated carbon layer is composed of an activated carbon inner protective layer, an activated carbon outer protective layer and two groups of internally filled activated carbon.

[0007] Compared with the prior art, the utility model has the advantages of:

[0008] Significantly improve the efficiency and water quality of seawater desalination:

[0009] The reverse osmosis membrane assembly of the utility model adopts multilayer composite membrane structure, including microfiltration membrane, ultrafiltration membrane and PA reverse osmosis membrane, and laminated prefilter layer and activated carbon layer, these design layers progress one after another, effectively remove suspended particles, bacteria, large particle organic matter, small molecule organic matter, oil and heavy metal ions in seawater, significantly improve the efficiency and effluent quality of seawater desalination.

[0010] Enhance the anti-pollution and stability of membrane assembly:

[0011] The PA reverse osmosis membrane prepared by adopting interface polymerization method combined with IP-UV graft polymerization coupling technology not only improves the interception performance and flux of the membrane, but also significantly enhances the anti-pollution of the membrane. The introduction of high solubility ionic liquid and new additives optimizes the structure and performance of the membrane, so that the membrane is not easy to be polluted in the long-term use process, prolongs the service life of the membrane. At the same time, the design of laminated prefilter layer and screen also effectively prevents the direct contact and clogging of the membrane holes by pollutants, further enhances the stability of the membrane assembly.

[0012] Optimize the pretreatment and cleaning unit, reduce the maintenance cost:

[0013] The seawater desalination system of the utility model designs efficient pretreatment unit and cleaning unit. The pretreatment unit removes most of the impurities in seawater through the layer-by-layer treatment of prefilter, membrane filtration assembly and adsorption filter, reduces the load of subsequent membrane assembly. At the same time, the introduction of automatic backwashing device can periodically or automatically start according to the water quality monitoring results, backwash the prefilter, prolong the service life of the prefilter and reduce the maintenance cost. The cleaning unit adopts the combination of ultrasonic cleaning and chemical cleaning, which can completely remove the pollutants on the surface of the membrane assembly, restore the flux and interception performance of the membrane assembly, reduce the system downtime and maintenance cost caused by membrane pollution.

[0014] Enhance the reliability and durability of the system:

[0015] The reverse osmosis membrane assembly and seawater desalination system of the utility model are made of high-strength and corrosion-resistant materials, such as inner membrane support layer made of polypropylene material and screen made of stainless steel wire mesh. These materials have good physical and chemical properties, can be used in harsh seawater environment for a long time without damage. At the same time, the multilayer composite membrane structure and the optimized cleaning unit design also enhance the reliability and durability of the system, so that the system can maintain high-efficiency and stable operation state for a long time. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the structure schematic view of the reverse osmosis membrane assembly of the utility model.

[0017] Figure 2 The utility model discloses a seawater desalination system schematic diagram.

[0018] The figure mark: 1, the cover; 2, reverse osmosis core; 3, inner membrane support layer; 4, laminated prefilter layer; 5, microfiltration membrane; 6, ultrafiltration membrane; 7, PA reverse osmosis membrane; 8, screen; 9, activated carbon inner protective layer; 10, activated carbon outer protective layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the utility model will be apparently and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model and not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the range protected by the utility model. EMBODIMENT

[0020] Please refer to Figure 1 The utility model provides a technical scheme: a reverse osmosis membrane assembly, the manufacture of reverse osmosis membrane assembly

[0021] Step one: prepare material

[0022] Inner membrane support layer 3: select high-strength, corrosion-resistant polypropylene material, after microporous treatment, to increase its surface area and filtration effect.

[0023] Microfiltration membrane 5: adopt polyvinylidene fluoride hollow fiber membrane, prepare two kinds of membranes with different molecular weight cut-off, and they are 500ku and 300ku respectively.

[0024] Ultrafiltration membrane 6: select polyether sulfone hollow fiber membrane, also prepare two kinds of membranes with different molecular weight cut-off, and they are 100ku and 50ku respectively.

[0025] Laminated prefilter layer 4: it is made of multiple layers of polypropylene fiber non-woven fabric, and a support framework is arranged between each layer to ensure the stability and filtration effect of the filter layer, and the molecular weight cut-off thereof is 50mu.

[0026] PA reverse osmosis membrane 7: the raw materials are m-phenylenediamine and benzene triformyl chloride, and additives 1-allyl-3-methyl imidazole chloride and tween 80.

[0027] Screen 8: it is woven by stainless steel wire mesh, and the mesh number is 100 to 200.

[0028] Activated carbon layer: it is composed of activated carbon inner protective layer 9, activated carbon outer protective layer 10 and two groups of internally filled activated carbon.

[0029] Step two: Assemble the reverse osmosis core 2

[0030] Place the treated inner membrane support layer 3 on the assembly table.

[0031] First wrap the laminated pre-filter layer 4 on the outside of the inner membrane support layer 3, and make sure the support skeleton is in the right position between the non-woven layers to increase the filtration area and effect.

[0032] Then wrap the two groups of microfiltration membranes 5 and the two groups of ultrafiltration membranes 6 on the outside of the laminated pre-filter layer 4 in turn, and make sure they are tightly attached without air bubbles or wrinkles.

[0033] Wrap the PA reverse osmosis membrane 7 on the outer layer of the ultrafiltration membrane 6. Pay special attention to the flatness and sealing of the membrane in this step.

[0034] Install the screen 8 behind the PA reverse osmosis membrane 7 to support and protect the subsequent activated carbon layer.

[0035] Finally, set up the activated carbon layer on the outside of the screen 8, which is composed of the activated carbon inner protective layer 9, the activated carbon outer protective layer 10, and the two groups of internally filled activated carbon, to ensure that the activated carbon layer can effectively adsorb organic matter and impurities in water.

[0036] Step three: Install the cover 1

[0037] Install the sealed cover 1 on both ends of the assembled reverse osmosis core 2 to ensure the sealing and integrity of the entire reverse osmosis membrane assembly.

[0038] Step four: Overall test:

[0039] Perform comprehensive performance tests on the assembled reverse osmosis membrane assembly, including but not limited to pressure test, permeation flux test, desalination rate test, and anti-pollution test; according to the test results, make necessary adjustments and optimizations to the assembly to ensure that all performance indicators meet the design requirements.

[0040] PA reverse osmosis membrane 7 production:

[0041] Step one: Interface polymerization preparation

[0042] Prepare the reaction monomers m-phenylenediamine and trimesoyl chloride, as well as the additive 1-allyl-3-methylimidazolium chloride.

[0043] Add high-solubility ionic liquid 1-allyl-3-methylimidazolium chloride to the aqueous phase, and adjust the solution concentration and pH value to the appropriate range.

[0044] Step two: IP-UV grafting polymerization coupling

[0045] Prepare the aqueous phase and the organic phase containing TMC and Tween 80 respectively, and make sure the reaction conditions are stable.

[0046] In the aqueous phase, the formation of the primary polyamide layer is promoted by controlling the diffusion rate of MPD.

[0047] A UV-initiated grafting polymerization step was carried out using a 254nm ultraviolet light source under nitrogen protection to ensure the uniformity and efficiency of the grafting reaction.

[0048] The reacted membrane was reconstructed by heat treatment, and heated continuously at a temperature range of 120°C to 150°C for 30 to 60 minutes to optimize the membrane structure and performance.

[0049] In the organic phase, Tween 80 reacts with TMC to generate TW-TMC products, which help to further improve the hydrophilicity and antifouling properties of the membrane.

[0050] Step 3: Membrane post-processing and testing

[0051] The prepared PA reverse osmosis membrane 7 is cleaned, dried, and its performance is tested to ensure that it meets the design requirements. Then it is assembled according to the steps above. Example

[0052] This utility model provides a technical solution: a reverse osmosis membrane module, and the manufacturing process of the reverse osmosis membrane module is as follows:

[0053] I. Material Preparation

[0054] Membrane material: High-performance polyamide (PA) material is selected as the main component of the reverse osmosis membrane. This material has excellent desalination performance, high flux and good antifouling properties.

[0055] Support layer: Polyester nonwoven fabric is used as the support layer. Its surface is smooth and free of loose fibers, which helps to form a stable membrane structure.

[0056] Intermediate carrier layer: A porous polysulfone (PSF) material with a diameter of approximately 150 angstroms (15 nanometers) is selected as the intermediate carrier layer, which can provide good support and filtration effect.

[0057] Separation layer: A highly cross-linked aromatic acrylic resin is used as the separation layer material. Its thickness is about 0.2 micrometers. It has high chemical stability and durability and is the key layer for achieving efficient desalination.

[0058] Other auxiliary materials include adhesives, sealing tapes, etc., used for the assembly and sealing of membrane elements.

[0059] II. Preparation Process

[0060] Membrane material preparation:

[0061] The polyamide material is pretreated, such as dissolution, filtration, etc., to ensure its purity and uniformity.

[0062] The treated polyamide material is deposited on the support layer by methods such as immersion, phase transfer or biaxial stretching, etc., to form a thin film.

[0063] The pore size and performance of the membrane are controlled through chemical modification and physical membrane structure adjustment to meet different filtration requirements.

[0064] Preparation of intermediate carrier layer and separation layer:

[0065] The polysulfone material is processed into a porous structure and fixed on the support layer to form an intermediate carrier layer.

[0066] A high-crosslinking aromatic acrylic resin is coated on the intermediate carrier layer to form an ultra-thin separation layer.

[0067] Membrane element assembly:

[0068] The prepared membrane sheets are stacked in a certain layering order to ensure tight adhesion between the layers and no air bubbles.

[0069] The adhesive is used to bond the layers of membrane sheets together to form a complete membrane element structure.

[0070] Sealing tape is used to seal the ends and sides of the membrane element to ensure the sealing and integrity of the membrane element.

[0071] Curing and post-processing:

[0072] The assembled membrane element is placed in a constant temperature and humidity space for curing treatment to improve the stability and durability of the membrane element.

[0073] The cured membrane element is subjected to necessary post-processing operations such as cleaning, testing, etc. to ensure that it meets the quality requirements.

[0074] Quality detection and packaging:

[0075] The membrane element is 100% detected by using automatic reverse osmosis membrane element detection equipment, including flow test, salinity test, pH test, and pollutant test, etc. to ensure that the membrane element meets the high-quality quality requirements.

[0076] The qualified membrane element is transported to the packaging workshop for sterile packaging to prevent contamination during transportation and storage. Embodiment

[0077] Please refer to Figure 2 The utility model provides a kind of technical scheme: a kind of efficient seawater desalination system, and the system includes pretreatment unit, reverse osmosis membrane component, control system and cleaning unit.

[0078] Pre-treatment unit:

[0079] Pre-filter: Stainless steel filter screen with a pore size of 50 μm is used as the pre-filter, which is installed at the seawater inlet to preliminarily filter out large-particle impurities such as seaweed and shell fragments in seawater.

[0080] Membrane filtration assembly:

[0081] Microfiltration membrane assembly: Polyvinylidene fluoride hollow fiber membrane is used to further remove small particles, colloids and part of bacteria in seawater.

[0082] Ultrafiltration membrane assembly: Polyether sulfone hollow fiber membrane is selected to remove smaller bacteria and suspended solids with relatively large molecular weight.

[0083] Adsorption filter: Activated carbon particles are built-in to adsorb small-molecule organic matter, oil, heavy metal ions and the like in seawater, thereby improving the quality of the effluent.

[0084] Automatic backwashing device: Installed after the pre-filter, equipped with a water quality monitoring sensor, when the water quality is detected to be decreased or the preset time is reached, the backwashing program is automatically started to remove impurities on the pre-filter.

[0085] Reverse osmosis membrane assembly:

[0086] The reverse osmosis membrane assembly of Example 1 is selected, which has high desalination rate, high flux and good anti-pollution property.

[0087] The membrane assembly is designed to be modular, which is convenient for replacement and maintenance.

[0088] Control system:

[0089] Equipped with a PLC programmable logic controller and a touch screen interface, the transmembrane pressure difference of each membrane assembly and the water quality parameters: turbidity, UV254 are monitored in real time.

[0090] The preset transmembrane pressure difference threshold is reached or exceeded, the cleaning program is automatically started.

[0091] Cleaning unit:

[0092] Ultrasonic cleaning equipment: Through ultrasonic vibration, loose dirt on the surface of the membrane assembly is preliminarily removed.

[0093] Chemical cleaning system: Including a cleaning liquid storage tank, a circulating pump and a heating device, which is used to configure and circulate chemical cleaning liquid to deeply clean stubborn pollutants in the membrane pores.

[0094] Pre-treatment effect analysis:

[0095] Record the turbidity and suspended solids content of seawater before and after pretreatment using water quality monitoring sensors to analyze the removal efficiency of the pre-filter and membrane filtration components.

[0096] Regularly check the clogging of the pre-filter and evaluate the effectiveness of the automatic backwashing device.

[0097] Performance monitoring of reverse osmosis membrane components:

[0098] Real-time monitoring of transmembrane pressure difference, recording and analyzing its trend to evaluate the degree of membrane component pollution and cleaning needs.

[0099] Regularly test the water quality parameters: turbidity, UV254, conductivity to ensure that the water quality meets the design requirements.

[0100] Cleaning effect evaluation:

[0101] After each cleaning, compare the transmembrane pressure difference and water quality before and after cleaning to evaluate the cleaning effect.

[0102] Analyze the synergistic effect of ultrasonic cleaning and chemical cleaning, optimize the cleaning program and cleaning fluid formula.

[0103] System maintenance and optimization:

[0104] According to the data analysis results, adjust the cleaning cycle and cleaning intensity of the pretreatment unit.

[0105] Optimize the cleaning strategy of reverse osmosis membrane components, reduce unnecessary cleaning times, and prolong the service life of membrane components.

[0106] Regularly check and maintain the system to ensure long-term stable operation of the system.

Claims

1. A reverse osmosis membrane module, characterized by: It includes reverse osmosis core (2) and the sealing installation of reverse osmosis core (2) both ends cover (1);The reverse osmosis core (2) includes the inner membrane support layer (3) in the middle and the two groups of microfiltration membrane (5) and two groups of ultrafiltration membrane (6) wrapped outside the inner membrane support layer (3), the microfiltration membrane (5) and ultrafiltration membrane (6) are wrapped between the inner membrane support layer (3) and set up the laminated prefilter layer (4), the microfiltration membrane (5) and ultrafiltration membrane (6) are wrapped with PA reverse osmosis membrane (7) behind, and set up the screen (8) behind PA reverse osmosis membrane (7), and set up the activated carbon layer outside the screen (8), and the activated carbon layer is composed of activated carbon inner protective layer (9), activated carbon outer protective layer (10) and two groups of internal filling activated carbon.

2. A reverse osmosis membrane module according to claim 1, wherein: The microfiltration membrane (5) adopts polyvinylidene fluoride hollow fiber membrane, and the molecular weight cut-off is 500ku and 300ku in turn, while the ultrafiltration membrane (6) adopts polyether sulfone hollow fiber membrane, and the molecular weight cut-off is 100ku and 50ku in turn, and the laminated prefilter layer (4) has a molecular weight cut-off of 50μm.

3. A reverse osmosis membrane module according to claim 2, wherein: The screen (8) is woven by stainless steel wire mesh, and the mesh count is 100 to 200, the inner membrane support layer (3) is made of high-strength, corrosion-resistant polypropylene material, and the surface is subjected to microporous treatment.

4. A reverse osmosis membrane module according to claim 3, wherein: The laminated prefilter layer (4) is stacked by multiple layers of polypropylene fiber non-woven fabric, and a support framework is arranged between each layer.

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