SWC5-8040 High Rejection Seawater RO Membrane For Large Desalination Plants

SWC5-8040 High Rejection Seawater RO Membrane For Large Desalination Plants

SWC5-8040 seawater reverse osmosis membrane is a mainstream 8-inch spiral wound SWRO element, matched with SWC4 high-salinity seawater membrane, SWC6 low-energy seawater RO membrane and large flow security filter cartridge for coastal seawater desalination, offshore platform water making and high TDS brackish water treatment. It adopts LD low-differential pressure anti-fouling structure and high-crosslink aromatic polyamide separation layer, reaching 99.8% nominal salt rejection and 92% typical boron removal rate, delivering stable high flux under 5.5MPa standard test pressure. This seawater membrane supports wide pH chemical cleaning, effectively alleviates concentration polarization and colloidal fouling, reduces energy consumption of large-scale desalination systems, and becomes the core filter component preferred by global marine engineering contractors and municipal desalination projects.

Product Description

SWC5-8040 seawater RO membrane element follows international standard 8040 spiral wound structural specification, belonging to medium energy-saving high-rejection SWRO series, which can form two-stage desalination system together with PROC10 standard brackish water RO membrane and EDI ultra-pure water polishing equipment to produce drinking water compliant with WHO standards. The overall dimension is 8-inch diameter × 40-inch length, with effective membrane area of 400 sq.ft (37.2㎡), rated permeate flow 9000GPD (34.1m³/d) under standard seawater test condition of 32000ppm NaCl solution. Different from ordinary high-pressure seawater membrane, SWC5-8040 optimizes feed spacer and membrane surface formula targeting coastal raw seawater containing algae, suspended colloid and boron compounds, balancing high salt rejection, boron interception and running energy consumption, without relying on ultra-high booster pressure to maintain stable daily water yield. The integrated end cap flow equalization structure eliminates water hammer damage during frequent start-stop of offshore water-making equipment, and is fully compatible with all universal 8-inch fiberglass and stainless steel membrane pressure vessels, no customized pipeline modification required for old desalination equipment renovation. All membrane raw materials meet food-grade water contact safety standards, no toxic monomer precipitation under long-term continuous high-pressure operation, suitable for 24-hour uninterrupted large-scale seawater desalination working conditions.

Working Principle

High-pressure seawater reverse osmosis separation mechanism is the core operation logic of SWC5-8040. Natural osmosis makes pure water molecules flow from low-concentration permeate side to high-salinity seawater side through semi-permeable membrane. When external pressure higher than seawater osmotic pressure (5.5MPa standard test pressure) is applied on the raw seawater side of SWC5-8040 element, the solvent flow reverses. Small water molecules penetrate dense polyamide thin-film composite layer and converge into central permeate tube, while NaCl salt ions, boron compounds, suspended colloids, marine algae and heavy metal particles are fully intercepted on feed water side to form concentrated brine discharged from concentrate channel. The built-in 34mil widened LD feed spacer generates continuous turbulent flow on membrane surface, weakening concentration polarization effect, slowing down pollutant deposition and realizing long-cycle stable separation of fresh permeate and concentrated seawater under constant high-pressure circulation.

Technical Features

1. 99.8% nominal high salt rejection & 92% typical boron removal rate

The proprietary high-crosslink aromatic polyamide membrane separation layer achieves nominal salt rejection up to 99.8%, minimum guaranteed desalination rate 99.7%, and typical boron interception efficiency 92%. It can effectively remove soluble sodium chloride, magnesium sulfate and trace boron elements in seawater, one-stage permeate TDS meets domestic water standards, eliminating secondary boron removal treatment for most coastal desalination projects.

2. 34mil LD low-differential pressure anti-fouling feed spacer

Compared with conventional 28mil thin spacer seawater RO membrane, 34mil widened flow channel reduces membrane surface concentration polarization by over 45%, single element maximum pressure drop controlled within 10psi. Marine colloids, algal sludge and organic contaminants are hard to accumulate, chemical cleaning cycle extends to 6–8 months, far longer than common seawater membrane products.

3. Ultra-smooth low-adsorption membrane surface treatment

Special hydrophilic coating forms ultra-smooth membrane surface with few adsorption sites, marine biological slime and humic acid substances hardly adhere to separation layer. After standard acid and alkali cleaning, flux recovery rate reaches 96% above, long-term operation flux attenuation is gentle without sharp performance decline.

4. Wide-range chemical cleaning pH tolerance

Continuous operation pH range 2–11, short-term chemical cleaning allowable pH expands to 1–13. Resistant to citric acid pickling, sodium hydroxide alkaline cleaning and sodium hypochlorite biocide, can thoroughly dissolve inorganic scaling, organic filter cake and biological film formed on membrane surface after long-term seawater operation.

5. 8.27MPa high pressure resistant integral winding structure

Maximum allowable operating pressure reaches 1200psig (8.27MPa), adapting to high-salinity deep seawater and high-recovery concentrated brine circulation systems. Integrated hot winding technology avoids membrane slice delamination under long-term high-pressure impact, reducing element rupture failure rate of offshore floating desalination equipment.

Product Advantages

1. Medium energy-saving design cuts overall desalination power consumption

Standard test pressure only 5.5MPa, stable flux within 5.2–6.0MPa operating window, lower booster pump power demand than ultra-high pressure seawater RO membrane. Large-scale coastal desalination plants can reduce total power consumption by nearly 28%, forming remarkable long-term electricity cost savings for million-ton water-making projects.

2. Extended service life lowers spare parts replacement cost

LD anti-fouling structure plus wide chemical cleaning window slows irreversible membrane fouling, actual service life reaches 3–4 years in coastal raw seawater working condition, 1.5 times longer than ordinary 8040 seawater membrane. Less membrane replacement frequency cuts procurement expense and equipment shutdown maintenance loss.

3. Universal 8040 standard size without equipment transformation

8-inch × 40-inch international standard dimension, compatible with all mainstream 8-inch membrane pressure vessels, connectors and O-rings on the market. Old offshore platform water-making equipment renovation can directly replace outdated membrane elements, zero extra cost for pipeline and support customization.

4. Strong anti-interference capacity adapts to fluctuating seawater quality

Stable rejection performance against seasonal seawater salinity, turbidity and algae content fluctuation. Even during rainy season coastal runoff mixing leads to raw water quality deterioration, permeate TDS and boron index still meet drinking water standards, avoiding production halt caused by unqualified fresh water output.

5. Low full-cycle operation and maintenance cost

Long chemical cleaning interval reduces cleaning agent consumption and manual labor hours; low membrane rupture failure rate cuts spare parts inventory cost; stable flux avoids excessive pump power waste, forming comprehensive low-cost operation advantage for medium and large seawater desalination systems.

Application Fields

1. Coastal municipal large-scale seawater desalination stations

Treat offshore raw seawater for municipal domestic tap water supply, one-stage permeate can be directly supplied to urban residents after simple disinfection, effectively solving coastal city fresh water shortage and meeting local environmental protection emission regulations.

2. Offshore oil & gas platform seawater desalination equipment

Deployed on floating production platforms to convert seawater into drinking water and equipment cooling replenishment water, compact 8040 size fits limited cabin space, stable high pressure resistance adapts to marine vibration and temperature fluctuation working conditions.

3. Island independent water-making engineering projects

Serve remote islands without land freshwater pipeline transportation, match pretreatment multi-media filter and security filter to build independent off-grid desalination system, fully meet island resident living and tourism base water demand.

4. High TDS brackish water desalination in inland salt lake areas

Process salt lake high-salinity raw water and underground brine with TDS above 30000ppm, remove excess salt and boron elements, produce fresh water for farmland irrigation and factory production water replenishment.

5. Marine aquaculture wastewater recycling treatment

Treat high-salinity breeding drainage, intercept residual bait organic matter, algae and soluble salts, recycled permeate for circulating aquaculture water, reduce seawater intake and waste brine discharge of large breeding farms.

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