Борьба с коррозией под воздействием морской воды: почему титановые насосы с разъемным корпусом доминируют в сфере опреснения воды

Seawater is one of the most aggressive fluids in industrial pumping. With chloride levels up to 19,000 ppm, a conductivity of ~50 mS/cm, and the constant threat of pitting, crevice corrosion, and stress corrosion cracking (SCC), standard pump materials like cast iron or even stainless steel 316L often fail within months. In the desalination industry – whether reverse osmosis (RO) or thermal multi-stage flash (MSF) – reliability is not optional. Downtime means lost fresh water production for entire communities.

So, what material truly conquers seawater? Титан.

In this post, we explain why titanium split case pumps from Hunan Durafort Pumps are the ultimate solution for beating seawater corrosion, and why they dominate the global desalination market.

The Corrosion Challenge in Desalination

Desalination plants handle either raw seawater (high chlorides, oxygen, microbes) or hot brine (concentrated salts, elevated temperatures up to 120°C+). Both environments attack conventional alloys:

• SS316L: PREN ~25 – suffers pitting and crevice corrosion in ambient seawater within 1-2 years.
• Super Duplex SS2507: PREN >40 – good but can still suffer localized attack in hot, stagnant conditions or in the presence of biofilms.
• Copper alloys: Susceptible to ammonia and sulfide attack; not suitable for high-velocity or polluted seawater.
• High-grade austenitic stainless (904L, 6% Mo): Expensive but still less corrosion-resistant than titanium in hot chlorides.

Titanium (Grade 2 or Grade 12) offers a quantum leap in corrosion resistance.

Why Titanium Split Case Pumps Dominate Seawater Service

1. Unbeatable Corrosion Resistance in Seawater

Titanium forms a tenacious, self-healing oxide film (TiO₂) that remains stable in seawater up to >120°C. It is virtually immune to:

• Pitting corrosion
• Crevice corrosion
• Stress corrosion cracking (SCC)
• Erosion-corrosion

In fact, titanium has been used in seawater-cooled condensers and desalination plants for over 50 years with virtually no corrosion failures. For a насос с горизонтально разделённым корпусом continuously handling raw or brine seawater, titanium delivers decades of service without material degradation.

2. High Strength-to-Weight Ratio

Grade 2 titanium has a yield strength of ~275–450 MPa (similar to 316L) but at only 60% of the density of steel (4.51 g/cm³ vs 7.9 g/cm³). This means:

• Lighter rotating components – lower bearing loads and reduced starting torque.
• Easier handling and installation – critical for large XSP pumps with flows up to 38,000 m³/h.

For higher pressure or cyclic duty, Grade 5 (Ti-6Al-4V) or Grade 12 titanium can be specified.

3. Excellent Resistance to High-Velocity Seawater

Seawater velocities above 3 m/s cause impingement attack on copper alloys and even some stainless steels. Titanium resists erosion-corrosion at velocities exceeding 10 m/s, making it ideal for:

• High-capacity seawater intake pumps
• Cooling water circulation in power-desalination co-generation plants
• High-flow brine recirculation in MSF units

4. Biofouling Resistance

Marine biofouling (mussels, barnacles, algae) often accelerates under-deposit corrosion on stainless steels. Titanium’s smooth, passive surface strongly resists biofouling, reducing maintenance cleaning frequency and chemical treatment costs.

Hunan Durafort XSP Titanium Split Case Pumps: Engineered for Desalination

Hunan Durafort Pumps is a professional pump manufacturer in China with extensive experience casting and fabricating titanium components. The Горизонтальный насос с разъемным корпусом XSP is available in titanium (Grade 2, Grade 12, or Grade 5) , alongside other alloys like carbon steel, SS316L, duplex 2205, супердуплекс 2507, 904L, and CD4MCu.

XSP Series Key Parameters (Titanium Construction)

Why the Split Case Design for Desalination?

• Top pull-out design: Impeller and wear rings can be inspected or replaced without disturbing piping or motor – critical for plants where downtime costs >$10,000 per hour.
• Double suction impeller: Hydraulically balanced, eliminating axial thrust, enabling higher speed and longer bearing life.
• High efficiency (87%): Lowers energy consumption – a major operational cost in desalination (energy can be 30-50% of water production cost).

Applications in Desalination Plants

1. Seawater Intake Pumps (RO and MSF)

Raw seawater from open intakes or beach wells. Titanium XSP pumps handle debris, sand, and full salinity without pitting or erosion. Flows up to 38,000 m³/h match large plant capacities.

2. High-Pressure Brine Recirculation (MSF / MED)

In multi-stage flash distillation, brine at 110°C with 2x seawater salt concentration is highly corrosive. Titanium Grade 12 (with added molybdenum and nickel) resists hot chloride SCC perfectly.

3. Cooling Water Supply for Co-Generation Plants

Many large desalination plants are paired with power plants. Titanium split case pumps provide cooling water to condensers and then feed the desalination process – a single corrosion-resistant pump serves two critical duties.

4. Chemical Dosing & Flushing Services

While smaller pumps are often used for anti-scalant or sodium bisulfite dosing, titanium XSP pumps can handle large-volume low-pressure flushing or emergency seawater supply.

Titanium vs. Other Materials for Desalination Pumps

Note: While titanium has higher upfront cost, its lifecycle cost in seawater service is often the lowest because of zero corrosion failures, minimal maintenance, and no replacement.

Real-World Success: Titanium Split Case Pumps in Action

A large Middle Eastern desalination plant (800,000 m³/day) switched from super duplex SS2507 seawater intake pumps to titanium after experiencing crevice corrosion under biofouling deposits every 3 years. The titanium XSP pumps from a Chinese manufacturer (like Hunan Durafort) have now operated for 8 years with zero corrosion-related downtime, paying back the premium in less than 2 years.

When Is Titanium the Right Choice for Your Split Case Pump?

• You are building or upgrading a seawater desalination plant (RO, MSF, MED).
• Your seawater temperature regularly exceeds 60°C (e.g., tropical climates or power plant cooling discharge).
• You have experienced pitting or SCC failures with duplex or super duplex stainless steels.
• You require a pump life of >15 years without major overhaul.
• Your plant has limited access for maintenance (offshore, remote location).

If any of these apply, a titanium horizontal split case pump is not an option – it is a necessity.

Why Choose Hunan Durafort Pumps for Titanium Split Case Pumps?

Hunan Durafort Pumps combines:

• Professional manufacturing of XSP split case, Вертикальный турбонасос LC, HD vertical mixed flow, и ZLB vertical axial flow pumps.
• Full material flexibility: carbon steel, ductile iron, SS304, SS316L, duplex 2205, super duplex 2507, 904L, CD4MCu, and titanium.
• High efficiency (87%) and large capacity up to 38,000 m³/h.
• Custom engineering: titanium casting and welding expertise, plus design for seawater/brine service.
• Global track record: serving municipal, power, marine, and industrial desalination markets.

Final Verdict: Titanium Split Case Pumps Dominate Desalination

When the goal is beating seawater corrosion reliably for decades, no material outperforms titanium. Its immunity to pitting, crevice corrosion, and SCC in hot, high-chloride environments makes it the undisputed champion for desalination pumps. The XSP horizontal split case pump from Hunan Durafort, available in titanium and other advanced alloys, delivers the flow, head, and efficiency that modern desalination plants demand – with the lowest total cost of ownership.

Ready to stop fighting corrosion? Contact Hunan Durafort Pumps today to discuss your seawater pumping requirements. Send your flow, head, temperature, and salinity data – we will recommend the optimal titanium grade and pump configuration.