Seawater Desalination
Seawater desalination systems require reliable and corrosion-resistant flow control. ZZJG butterfly valves are widely used in seawater intake, pretreatment, and desalination processes, offering durable sealing, stable operation, and long service life in harsh marine environments.
Seawater Intake
Flange Type Centric Butterfly Valve
Media & Conditions: Raw seawater with sediment & microorganisms. Low pressure (PN10/16), large diameter (DN300+).
Recommended Materials
- Body: GGG50 + 250μm Fusion Bonded Epoxy (FBE) Coating
- Disc: C95800 (Aluminum Bronze) or 2507 (Super Duplex Steel)
- Shaft: Monel K500 or 2507
- Seat: EPDM
Operation
- Selection Challenge: Strong corrosion, biofouling, and partial abrasion.
- Recommended Actuator: Electric / Manual Gear
Selection Reasoning
Rigidity & Economy: For large diameters, flanged connections offer superior pipeline rigidity and sealing. A ductile iron body with a heavy-duty coating (compliant with EN-ISO 12944 C5-M) is the best balance of corrosion protection and cost.
Anti-Corrosion: Aluminum Bronze (C95800) naturally resists seawater corrosion and bio-adhesion. Super Duplex (2507) is a higher-performance option for more aggressive water quality.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
Pre-treatment
Heavy-Body Wafer/Lug Butterfly Valve
Media & Conditions: Filtered seawater with small amounts of chemicals (e.g., flocculants, chlorine). Low pressure (PN16), frequent cycling.
Recommended Materials
- Body: CF8M (316 Stainless Steel)
- Disc: 2205 (Duplex Steel) or 2507
- Shaft: 2205 or 17-4PH
- Seat: EPDM (General) / HTEPDM (at chlorination points)
Operation
- Selection Challenge: Sustained corrosion and durability under frequent operation.
- Recommended Actuator: Pneumatic
Selection Reasoning
Cost-Effectiveness & Durability: Wafer/Lug styles are flexible and economical. The heavy-body design is optimized for frequent cycling, withstanding higher torque and potential water hammer.
Precise Material Matching: 2205 Duplex Steel offers excellent cost-performance in this role, fully resisting filtered seawater. A CF8M body provides superior corrosion resistance compared to coated cast iron.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
HP Pump / RO Feed
Triple Offset Double Flanged Butterfly Valve
Media & Conditions: Clean seawater, ultra-high pressure (PN63/PN100), Temp < 45°C.
Recommended Materials
- Body: 2507 (Super Duplex Steel) or 1.4529 / 6Mo
- Disc: 2507 (Super Duplex Steel)
- Shaft: 2507 (Super Duplex Steel)
- Seat: SS316+Graphite (Laminated Metal Seat)
Operation
- Selection Challenge: Ultra-high pressure, strong corrosion, and absolute zero-leakage requirement.
- Recommended Actuator: Pneumatic (with Spring Return) / Electric
Selection Reasoning
Ultimate Performance Guarantee: This is the system core, demanding the strictest performance. The "torque-sealing" and "friction-free" design of a Triple Offset Valve (TOV) achieves durable, zero-leakage with a metal seat, perfectly handling ultra-high pressure.
Top-Tier Materials: A full Super Duplex (2507) or 6Mo Austenitic Stainless Steel package is the industry standard to resist high-pressure, high-velocity chloride crevice corrosion and pitting. The double flanged structure provides maximum rigidity for high-pressure lines.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
RO Brine/Concentrate
High-Performance Double Offset or Triple Offset Valve (Wafer/Lug)
Media & Conditions: High salinity concentrated seawater (salinity x2), high pressure (PN63).
Recommended Materials
- Body: 2507 (Super Duplex Steel)
- Disc: 2507 or 1.4529 (926)
- Shaft: 2507 or Hastelloy C-276
- Seat: RPTFE (Double Offset) / Metal Seat (Triple Offset)
Operation
- Selection Challenge: Extreme corrosiveness and high pressure.
- Recommended Actuator: Electric
Selection Reasoning
Confronting Extreme Corrosion: Concentrate brine is the most corrosive medium in the plant. A High-Performance Double Offset valve is the economical solution, while a Triple Offset offers a longer service life and more reliable shutoff.
Material Upgrade is a Must: Materials must start at Super Duplex. For modulating service or lines with energy recovery devices, the shaft may even require Hastelloy (C-276) to withstand the harsh challenges of high-velocity flow.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
Product / Permeate Water
General Service SS Centric Wafer Butterfly Valve
Media & Conditions: Ultra-pure or drinking water, low pressure (PN10/16).
Recommended Materials
- Body: CF8M (316 Stainless Steel)
- Disc: CF8M (316/316L) with mirror polish
- Shaft: SS316L
- Seat: EPDM (with drinking water certification, e.g., WRAS, NSF-61)
Operation
- Selection Challenge: Preventing secondary contamination, meeting hygienic standards.
- Recommended Actuator: Manual (Lever/Gear) / Electric
Selection Reasoning
Clean & Contaminant-Free: 316/316L stainless steel is sufficient for pure water and will not leach contaminants. A mirror-polished disc reduces bacterial adhesion and is easier to clean.
Safety Certification: The seat material MUST be certified to drinking water standards like WRAS or NSF/ANSI 61 to ensure the final product water is safe for consumption.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
Brine Discharge
Flanged or Heavy-Body Wafer/Lug Type
Media & Conditions: High salinity concentrated seawater, pressure reduced to < PN10.
Recommended Materials
- Body: GGG50 + 250μm FBE Coating
- Disc: 2205 (Duplex Steel) or C95800 (Aluminum Bronze)
- Shaft: 2205 or Monel K500
- Seat: EPDM
Operation
- Selection Challenge: Strong corrosion resistance and cost-effectiveness for large diameters.
- Recommended Actuator: Electric / Manual Gear
Selection Reasoning
The Cost/Performance Sweet Spot: With pressure reduced, the main challenge is corrosion. The combination of a "coated ductile iron body + Duplex/Bronze disc" is the most classic and cost-effective solution for low-pressure, highly corrosive brine, widely proven in global desalination projects.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
Chemical Dosing / CIP
Stainless Steel Wafer Butterfly Valve
Media & Conditions: Acids, alkalis, sodium hypochlorite, antiscalants. Low pressure, small diameter.
Recommended Materials
- Body: CF8M (316 Stainless Steel)
- Disc: CF8M / 2205 (depending on chemical)
- Shaft: SS316 / 2205
- Seat: PTFE / FKM (Viton®)
Operation
- Selection Challenge: Resistance to specific, strong chemical corrosion.
- Recommended Actuator: Pneumatic / Electric
Selection Reasoning
The Seat is Key: The critical factor here is the seat's chemical resistance. PTFE is resistant to nearly all chemicals; FKM (Viton®) has excellent resistance to a wide range of chemicals and oils.
Targeted Material Selection: For strong oxidizing agents like sodium hypochlorite, upgrading the disc and stem to 2205 Duplex Steel is recommended to prevent pitting corrosion.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
Equipment Isolation
Same type as main valve, but with manual operator
Media & Conditions: Covers all plant media; operated only during maintenance.
Recommended Materials
- Body: Match material of the pipeline
- Disc: Match material of the pipeline
- Shaft: Match material of the pipeline
- Seat: Match material of the pipeline
Operation
- Selection Challenge: Reliable shutoff, cost-effectiveness, and operability after long static periods.
- Recommended Actuator: Manual Gear (DN>150) / Manual Lever (DN≤150)
Selection Reasoning
Practicality First: Isolation valves are for manual operation, so expensive automation is unnecessary. The core requirement is "it must close reliably when needed."
Cost Optimization: Selecting the same or slightly lower material configuration as the main pipeline valve balances safety with cost control. For example, using a "coated iron body + 2205 disc" for a seawater line isolation valve is a best practice.
Let our engineers analyze your application and demonstrate how a purpose-built valve can lower your Total Cost of Ownership and bring stability to your operations.
ZZJG SOURCE FACTORY
We are not just a supplier, we are your manufacturing partner. Our integrated capabilities provide unmatched quality control, flexibility, and value.
Source Factory · Flexible Customization
As a source factory, ZZJG delivers premium valves directly to you, offering flexible designs to meet all your industrial needs.
Integrated Casting · Superior Performance
ZZJG valves combine state-of-the-art integrated casting with rigorous quality control to provide high-performance, reliable valves for every project.
API Certified, Guaranteed Reliability
ZZJG’s API-certified valves deliver superior safety, compliance, and operational excellence—direct from our factory to your project.
From Raw Material to Finished Product
1. Raw Material Inspection
2. In-House Foundry Casting
3. Precision CNC Machining
4. Fusion Bonded Epoxy Coating
5. Assembly & Pressure Testing
6. Final Product Ready for ShipmentTechnical Deep-Dive
Material Science for Seawater Service
Selecting the right alloy is the single most important factor for valve longevity in desalination. Here’s why we use specific grades:
- Duplex (2205) & Super Duplex (2507)
- These are the workhorses. Their high chromium, molybdenum, and nitrogen content provides excellent resistance to chloride pitting and crevice corrosion. PREN value (Pitting Resistance Equivalent Number) quantifies this: 2205 PREN ≈ 35, 2507 PREN > 40. Super Duplex is essential for high-pressure, high-salinity brine.
- Nickel-Aluminum Bronze (e.g., C95800)
- Offers outstanding resistance to biofouling and general seawater corrosion. It's an extremely cost-effective choice for seawater intake lines where marine growth is a primary concern.
- Monel & Hastelloy
- These nickel-based alloys provide ultimate resistance in the most aggressive conditions, such as high-velocity, high-concentration brine or specific chemical dosing lines. They are specified when even Super Duplex may face challenges.
Actuation & Control Options
The right actuator ensures reliable operation and system safety. We configure each valve for its specific duty:
- Manual (Lever / Gear)
For isolation and infrequent operation. We offer lockout-tagout (LOTO) accessories for safety, and gear operators can be fitted with a tamper switch to signal unauthorized operation.
Use-case: Equipment Isolation Valves. - On/Off Actuation (Electric / Pneumatic)
For automated open/close sequences. This is the most common automated setup for isolation tasks.
Use-case: Pre-treatment filter backwash sequence. - Modulating Actuation (Electric / Pneumatic)
For precise flow control, typically using a 4-20mA signal. Paired with our high-performance or triple-offset valves for accurate throttling.
Use-case: Controlling flow to energy recovery devices. - Fail-Safe Actuation (Spring-Return Pneumatic)
Designed for emergency shutdown (ESD). The valve automatically closes (or opens) upon loss of air pressure or power, ensuring plant safety.
Use-case: High-pressure pump outlet emergency isolation.
API 609
BV
ISO 9001
CE/PED
DNV
ZZJG Butterfly Valves
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