50 T/Day Marine Seawater Desalination System
A commercial cargo vessel operating in tropical regions required a reliable freshwater supply for crew consumption, equipment cooling, and onboard services. With limited access to port facilities and high freshwater costs in remote areas, the shipowner sought a compact, energy-efficient seawater desalination system capable of producing 50 tons of freshwater per day.
Facing the following challenges
1. Space limitations: The installation space for vessel’s engine room is limited.
2. High salinity and high temperature: Operating in seawater with a salinity as high as 45,000 ppm and a temperature up to 35°C.
3. Energy Efficiency: Minimize power consumption to be in line with the capacity of the ship's diesel generator.
4. Durability: Resistant to corrosion, vibration and fluctuating working conditions.
VOCEE Solution
A reverse osmosis (RO) desalination system was designed and installed, optimized for marine environments.
Key features included:
1.Compact Modular Design: Pre-engineered skid-mounted components for easy integration into tight spaces.
2.High-Efficiency RO Membranes: Dow Filmtec™ SW30HRLE-400 elements to handle high salinity and temperature.
3.Energy Recovery Device (ERD): Reduced energy consumption by 35% by recycling hydraulic energy from the brine stream.
4.Automated Control System: PLC-based interface for real-time monitoring of pressure, salinity, and flow rates, with automatic flushing and shutdown protocols.
Main Technical Specifications
1)Capacity: 50 m³/day (12,500 gallons/day) at 40% recovery rate.
2)Power Consumption: 3.8–4.2 kWh/m³ (including pretreatment and pumps).
3)Output Water Quality: < 700 ppm TDS, compliant with WHO drinking standards.
4)Pretreatment: Multi-media filtration, security filters (5 μm), and antiscalant dosing to prevent membrane fouling.
5)Materials:High-pressure pump made of duplex steel 2507, FRP membrane housings, and corrosion-resistant piping.
Results
1)Reliable Supply: Achieved consistent 50 T/day output, meeting 100% of the vessel’s freshwater demand.
2)Cost Savings: Reduced freshwater procurement costs by $12,000/month.
3)Energy Efficiency: Energy consumption lowered to 3.9 kWh/m³, compatible with the vessel’s 440V/60Hz power system.
4)Low Maintenance: Automated CIP (clean-in-place) cycles extended membrane life to 3+ years.
