Shanghai Tongjie pitches offshore seawater desalination plants for rigs and vessels

Shanghai Tongjie says offshore drilling rigs, FPSOs and marine vessels can cut freshwater logistics costs by producing potable and technical water onboard from seawater. The company outlines plant sizing, redundancy, hazardous-area standards and remote monitoring for offshore operators.

Why it matters: - Offshore operators depend on steady freshwater for crew health and core technical work, including drilling mud preparation, boiler makeup, turbine washing and deck sanitation. - Onsite desalination can reduce reliance on supply barges that are expensive and vulnerable to weather delays. - Shanghai Tongjie says offshore freshwater produced onboard can lower operating costs and improve supply security.

What happened: - Shanghai Tongjie Environmental Protection Technology Co., Ltd. promoted its offshore seawater desalination systems on Sept. 18, 2026, from Shanghai. - The company positioned its equipment for offshore drilling rigs, FPSOs, pipelay barges, construction vessels and other commercial marine assets. - The release framed shipboard desalination as a replacement for water bunkering via supply boats.

The details: - Shanghai Tongjie distinguishes between compact marine watermakers and full shipboard seawater desalination plants. - Compact watermakers are described as 1 to 20 tons per day, designed for tugboats, trawlers and utility craft with intermittent 8- to 12-hour runtimes. - Full shipboard desalination plants are described as 50 to 500+ tons per day, built for continuous 24/7 operation on larger offshore assets. - The larger systems include multi-stage pretreatment, high-pressure pumps, duplex stainless manifolds, energy recovery devices and automated safety interlocks. - Offshore water demand is split into three streams: potable life-support water, technical process and boiler makeup water, and drilling mud and heavy utility water. - Potable water is described as meeting WHO and MLC standards, with TDS under 500 mg/L, neutral pH and zero coliforms. - Technical water for turbines and boilers is described as requiring two-pass RO or RO-EDI polishing, with conductivity below 1 to 5 µS/cm and silica under 10 ppb. - Drilling mud and heavy utility water are described as needing basic desalting, with TDS below 1,000 mg/L. - The company says offshore systems should be sized around feedwater conditions, salinity shifts, contaminant loads, runtime needs and peak demand. - Open-ocean seawater is described as ranging from 32,000 ppm in open seas to 45,000 ppm in enclosed gulfs. - The release says equatorial water above 35°C raises biofouling risk, while sub-arctic water below 4°C raises viscosity and feed-pressure needs. - For continuity, the release recommends redundant trains such as 2 x 50% or 3 x 33% configurations. - Offshore skids and containerized modules should be certified for lifting under DNV GL-ST-E271 or ISO 10855, the release says. - In hazardous Zone 1 and Zone 2 locations, the skids are described as requiring ATEX or IECEx explosion-proof construction, Ex d motor enclosures, Ex p control cabinets and intrinsically safe sensors. - External interfaces must be planned for suction, three-phase power and brine discharge. - High-pressure seawater manifolds operating at 55 to 70 bar are described as needing 2507 super duplex stainless steel or duplex 2205 alloys. - Low-pressure manifolds are described as suitable for FRP or Schedule 80 UPVC. - External frames are described as needing marine epoxy coatings that meet ISO 12944 C5-M durability criteria. - Shanghai Tongjie says its offshore desalination plants include remote SCADA integration that sends operating data to onshore technical centers. - The monitored data includes membrane flux, recovery rates, inter-stage pressure drops and permeate conductivity. - The release says isobaric energy recovery devices can reduce specific energy consumption from about 7.5 kWh/m³ to 3.0 to 3.5 kWh/m³.

Between the lines: - Shanghai Tongjie is selling offshore desalination as both a logistics tool and a reliability upgrade. - The emphasis on redundancy, hazardous-area compliance and remote monitoring suggests the target market is oil, gas and industrial marine operations where downtime is costly. - The economics section is meant to sharpen the case against water bunkering by comparing delivered water costs with onsite operating costs.

What's next: - Shanghai Tongjie is asking operators to submit vessel type, daily freshwater volume, power parameters and deck layout constraints. - The company says its offshore engineering team can then provide custom P&IDs, general arrangement drawings and lifecycle economic assessments. - The release points operators to Shanghai Tongjie for custom plant configuration work based on site-specific conditions.

The bottom line: - Shanghai Tongjie is pitching shipboard desalination as a lower-cost, lower-risk way for offshore operators to secure freshwater without relying on barges and port logistics.