SW30XHR-400/34i Seawater RO Membrane – Ultra High Rejection For Cold High Salinity Seawater

Product Introduction

As a full-spectrum industrial liquid filtration solution supplier centered on Liquid Filters, we develop dedicated seawater separation elements to address the long-standing pain points of coastal desalination projects. The SW30XHR series, represented by SW30XHR-400/34i, is categorized as professional seawater RO membrane, engineered with ultra-high salt rejection performance to adapt to two harsh raw water conditions that plague conventional desalination components: high salinity seawater and low-temperature coastal seawater.

Coastal seawater varies drastically with seasons and geographic locations. Cold winter seawater reduces the permeability of ordinary seawater RO membrane, leading to insufficient daily water output; offshore high-salinity seawater imposes heavy ion interception pressure on standard elements, resulting in elevated permeate TDS that fails to meet domestic and industrial freshwater standards. SW30XHR-400/34i adopts a compactly optimized polyamide separation layer structure, locking in ultra-stable ultra-high rejection under both low-temperature and high-salinity working conditions. It follows universal 8-inch spiral wound dimensional specifications, compatible with all mainstream seawater pressure vessels on the market, supporting direct replacement of aging desalination membrane elements without large-scale pipeline and high-pressure pump reconstruction. It has become the core pre-desalination component for coastal municipal freshwater stations, offshore platform water supply systems, and industrial seawater desalination facilities.

Working Principle of Ultra High Rejection Low-Temperature Seawater RO Membrane

Separation follows the standard solution-diffusion mechanism of reverse osmosis, rather than simple physical screening. The dense cross-linked polyamide active layer acts as a selective barrier: water molecules dissolve and diffuse through the membrane matrix under designated seawater driving pressure, while sodium, magnesium, chloride and other monovalent and divalent salt ions are repelled via Donnan electrostatic exclusion effect to achieve deep desalination.

Compared with conventional standard seawater RO membrane elements, SW30XHR-400/34i upgrades two core structural designs to fit cold high-salinity seawater scenarios. First, the tightly arranged molecular structure of the separation layer raises baseline salt rejection, effectively intercepting massive dissolved ions in high-salinity raw water. Second, the optimized hydrophilic membrane surface retains stable water molecule permeability at low temperatures, mitigating severe flux attenuation that commonly occurs to ordinary elements in winter coastal environments. Equipped with wide streamline feed spacers, it eliminates internal flow dead zones and suppresses concentration polarization, avoiding gradual rejection decline caused by local salt accumulation during long-term continuous desalination operation.

Under standardized chemical cleaning procedures (pH 1–13, cleaning temperature ≤35°C, single cycle within 2 hours), its salt rejection and permeate flux can recover to more than 96% of factory calibrated values, maintaining consistent ultra-high desalination capacity for year-round cold and high-salinity seawater treatment cycles.

Core Standard Technical Parameters

All certified indicators are measured under unified seawater simulation test conditions, fully matching the working environment of coastal desalination projects:

• Product Positioning: Ultra high rejection spiral wound seawater RO membrane for cold, high-salinity seawater

• Structural Type: Spiral wound industrial RO membrane element

• Standard Test Condition: 25°C, 800 psi, 32000 ppm simulated seawater

• Stabilized Salt Rejection Rate: ≥99.8%

• Rated Permeate Flux (8040 spec): 7600–8900 GPD

• Continuous Operating Pressure Range: 600–900 psi

• Maximum Continuous Operating Temperature: ≤45°C

• Minimum Applicable Raw Water Temperature: 5°C

• Long-Term Stable Operating pH Range: 2.0–11.0

• Short-Term Chemical Cleaning pH Limit: 1.0–13.0

• Maximum Allowable Feed Water SDI: ≤3

• Single Element Pressure Drop: ≤15 psig

Official Performance Guarantee Clauses For Desalination Tender & Contract

1. Flux and salt rejection data are calibrated at 25°C standard temperature; permeate flux drops roughly 3% per 1°C temperature reduction. Temperature correction coefficients must be applied for engineering design calculation of winter cold seawater projects.

2. Stable ≥99.6% minimum salt rejection can be guaranteed within operating temperature 5–45°C and feed water salinity ≤38000 ppm.

3. Long-cycle ultra-high rejection performance is premised on complete removal of free chlorine in pretreatment system to prevent irreversible oxidation damage to the polyamide separation layer.

Core Product Advantages For Cold High Salinity Seawater Desalination

1. Ultra-high salt rejection stabilizes permeate water quality for high-salinity seawater

   With certified ≥99.8% stabilized salt rejection rate, SW30XHR-400/34i delivers deep interception of dissolved mineral ions in high-salinity offshore seawater. It effectively lowers permeate TDS to meet drinking water and industrial process freshwater standards in a single separation stage, reducing the post-treatment load of secondary polishing equipment and cutting chemical consumption for downstream water adjustment processes.

2. Optimized low-temperature permeability avoids seasonal flux shortage

   The hydrophilic modified separation layer maintains stable water permeability at raw water temperatures as low as 5°C, solving the core pain point of drastically reduced daily water output for desalination stations in cold coastal winters. Compared with standard seawater RO membrane, it maintains 18%–25% higher effective flux under identical low-temperature raw water conditions, eliminating the need for auxiliary raw water heating equipment and lowering overall system energy expenditure.

3. Wide anti-concentration-polarization flow channel adapts to 24/7 uninterrupted desalination

   Wide streamline feed spacers eliminate internal dead zones and slow salt deposition on the membrane surface during round-the-clock continuous operation. Compared with conventional seawater elements, its routine chemical cleaning cycle can be extended by 20–25 days based on the 90-day standard cycle of ordinary desalination membranes, reducing system shutdown maintenance frequency and improving the continuous water supply stability of coastal desalination projects.

4. Universal standard spiral wound size lowers renovation investment

   SW30XHR-400/34i adopts unified 8-inch industrial spiral wound dimensions, fully compatible with mainstream seawater pressure vessels on the market. When aging membrane elements lose performance, direct plug-and-play replacement can be completed without pipeline or high-pressure pump reconstruction, shortening the construction cycle of desalination system upgrades and reducing equipment transformation costs for water treatment operators.

5. Excellent cleaning recovery extends overall RO membrane lifespan

   The anti-scaling hydrophilic surface delivers outstanding performance recovery after standardized acid-base cleaning. Under qualified pretreatment and regular maintenance cycles, the element retains qualified ultra-high rejection indicators for extended service cycles, reducing the annual membrane replacement quantity of large-scale seawater desalination stations.

Application Fields

Relying on its dual core strengths of ultra-high salt rejection and low-temperature flux stability, SW30XHR series elements represented by SW30XHR-400/34i are widely deployed in all seawater desalination scenarios facing cold or high-salinity raw water. All design and performance indicators conform to national seawater desalination engineering industry specifications.

• Coastal municipal seawater desalination plants: Core desalination component for large-scale urban freshwater supply, adapting to seasonal temperature fluctuations and offshore high-salinity raw water intake.

• Offshore oil & gas platform water supply systems: Compact RO units for isolated marine facilities, stably producing qualified drinking and process freshwater from year-round cold seawater.

• Island resident freshwater stations: Small and medium-sized desalination equipment for remote islands with high-salinity surrounding seawater and low annual average water temperature.

• Industrial coastal factory desalination projects: Supporting continuous production process water supply for chemical, aquaculture and port manufacturing enterprises, handling fluctuating raw water salinity and temperature.

For seawater desalination EPC engineers and water station design institutes, complete salt rejection, low-temperature flux and temperature correction test data provide reliable basis for membrane quantity, high-pressure pump and pretreatment system sizing, supporting standardized design of low-maintenance desalination RO systems adapted to harsh coastal water quality.

Quality Control Standards

Every batch of SW30XHR-400/34i seawater RO membrane undergoes simulated cold high-salinity seawater full performance testing before delivery, with serial-numbered inspection reports recording salt rejection, low-temperature flux, pressure drop and cleaning recovery indicators. The whole production flow complies with ISO 9001 quality management system, all water-contact raw materials satisfy industrial seawater desalination safety specifications, and core ultra-high rejection indicators pass third-party desalination engineering certification.

Complete datasheets with temperature correction curves, low-temperature operation guidelines and batch traceability documents are delivered together for project tender filing, engineering design and plant acceptance inspection. Finished membrane elements are vacuum sealed with dedicated anti-drying preservation liquid to avoid separation layer damage during transit and storage, ensuring on-site installation performance consistent with factory certified ultra-high rejection benchmarks under qualified pretreatment conditions.

Future Development Direction

Our R&D team continues to optimize the polyamide separation layer compactness and low-temperature hydrophilic modification formula for this SW30XHR series seawater element. Ongoing material upgrades target further stabilization of long-cycle ultra-high salt rejection and enhanced tolerance to extreme low-temperature seawater fluctuations, reinforcing the low-maintenance, long-life performance that coastal desalination systems require. Future generations of this series will retain universal standard spiral wound sizes while further reducing operating pressure demand to cut full-cycle energy consumption for large desalination projects.

Summary

This industrial spiral wound seawater RO membrane model SW30XHR-400/34i takes certified ultra-high salt rejection and stable low-temperature flux as core technical advantages, specially developed to solve the dual challenges of high-salinity and cold raw water in coastal seawater desalination projects. Through compact optimized polyamide separation layer and wide anti-concentration-polarization feed spacer design, it realizes deep interception of dissolved salts under year-round fluctuating seawater temperature and salinity conditions.

Compared with conventional standard seawater RO membrane elements, SW30XHR-400/34i maintains consistent stable permeate water quality and sufficient daily water output in harsh coastal water environments, effectively reducing post-treatment chemical consumption, auxiliary heating energy costs and maintenance downtime, bringing reliable freshwater supply guarantee and long-term operation cost reduction for coastal desalination stations, offshore platforms and island water facilities. For seawater desalination EPC companies, marine facility operation and maintenance teams and coastal water treatment design institutes pursuing stable ultra-high rejection performance in cold high-salinity seawater, it is a professional high-performance industrial seawater RO element solution.

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