Builder of water processing systems in USA since 1929 – and trusted for diverse extreme applications from military to offshore, Aqua-Chem is the leading water treatment company in the world, providing complete range of thermal and membrane treatment technologies.


Aqua-Chem’s vapor compression distillation watermakers provide reliable, proven solutions for offshore desalination of seawater, killing bacteria and removing suspended solids, dissolved minerals and organic contaminants. These units are designed to operate in the challenging conditions encountered in offshore operations, and are backed by decades of successful operating history. Our vapor compression distillation watermakers consistently produce purified water with less than 5 ppm of total dissolved solids.

Design Features

Evaporator – The evaporator features a horizontal design using the patented Spray-Film® process. In use for over 40 years now, this technology continues to be the design of choice in conditions that demand maximum reliability, lowest operating costs and maximum production.

Heat Source – The vapor compression process uses its own compressed steam as its primary heat source, resulting in vastly improved efficiency.

Materials of Construction – We use corrosion-resistant titanium and copper-nickel tubes, titanium compressor impellers and heat exchangers, plus copper-nickel evaporator shells.

Automation – Watermakers are designed to operate automatically with a pushbutton start. A programmable logic controller (PLC) and human machine interface (HMI) are standard.

Insulation – The evaporator is insulated with fiberglass and covered with aluminum cladding.

  • From the North Sea to Southeast Asia, you can count on crystal-clear water at the rated capacity, confident that performance, capacity and water quality are not affected by feedwater characteristics.
  • Custom engineering is available to meet international electrical codes, rig specifications and unique operating conditions.
  • Patented Spray-Film evaporator design provides improved wetting of the tube bundle which minimizes scaling. This means less downtime for cleaning and less chemical use.
  • Spray-Film design also includes built-in, on-line cleaning for removing any scale, reducing maintenance costs and increasing operating life.
  • The most reliable steam compressor design incorporates a unique journal bearing with thin film technology for long-lasting performance, which is superior to ball bearings.
  • Simple layout improves safety and ease of maintenance to extend operating life. All major components are accessible from floor level, with the compressor and pumps located at the edge of the skid for easy serviceability.
  • Easy, low-cost installation, with only five piping connections and one electrical connection.
  • Reliable and durable materials with proven performance after more than four decades of offshore use by Aqua-Chem.
  • Factory tested to ensure trouble-free startup.
  • Efficiency is 0.05-0.07 kw per gallon of purified water produced.
Operating Characteristics
Type Rate SR200 SR300 SR400 SR600 SR700
Flows Feedwater Gallons Per Hour 400 600 800 1200 1400
Cubic Meters PerDay 36.4 54.5 72.7 109 127
Blowdown Gallons Per Hour 200 300 400 600 700
Cubic Meters PerDay 18.2 27.3 36.4 54.5 63.6
Distillate Gallons Per Hour 200 300 400 600 700
Cubic Meters PerDay 18.2 27.3 36.4 54.5 63.6
Power Motor Size
Compressor 20 30 40 50 60
Rec. Pump 3 3 5 7.5 7.5
Dist. Pump 2 2 2 2 2
Lube Oil 0.5 0.5 0.5 0.5 0.5
Electric Heaters
With Plate Type
Heat Exchanger
(3) 9 (3) 9 (3) 12 (3) 12 (3) 12
Motor Operating
Power at Rated
Capacity Kw/Hr
Compressor & Pumps 16 21.5 30 39.5 43
Heat Make Up Heat
Electrical (Kw) 12 14 14 18.5 18.5
Steam Lb/Hr 42 50 50 65 68
Steam Kg/Hr 19 23 23 30 32
All Electric Unit Kw - Hr / Hr 28 35.5 44 58 60.5
Steam Make Up
Kw - Hr / Hr 26 21.5 30 39.5 44.5
Electric Motor
Drive w/Steam
Make Up Heat
Kw 18 25.5 34.5 44.7 53
All Electric Kw 45 52.5 70.5 80.7 89.1
Economy All Electric Kw - Hr / 1000 gal. 140 118 110 96 95
Specific Energy Btu/Lb of Product Water 57 48 45 39.4 38.5


Aqua-Chem supplies an innovative vacuum vapor compression desalination system. Vacuum evaporation improves the performance of the distillation process by lowering the evaporation operating temperature. The lower operating temperature retards the formation of scale, improves the heat transfer and reduces maintenance and chemical cleaning cycles.

Design Features

Compressors – Our compressors use high-speed journal bearings to ensure maximum life. In addition, Thin Film Oil technology protects the bearings and shaft from wear. Materials of construction include titanium impellers and 90/10 CuNi or stainless steel housing.

Evaporator – The evaporator features a horizontal shell and tube design that uses the Spray-Film® process.

Heat Source – The vapor compression process uses its own compressed steam as its primary heat source, resulting in vastly improved efficiency.

Vacuum Evaporation Technology – Vacuum evaporation technology reduces the boiling point of the water to less than 150° F, which helps to retard the formation of scale while concurrently increasing the running time between maintenance and cleaning.

Custom Design – Our units can be easily customized to comply with standards established by CE, ABS, DNV and others. The flexibility to make modifications to meet your specific requirements helps set us apart in the industry.

Materials of Construction – Our components are made of the strongest, most durable materials available to extend system life. Evaporator shells include 90/10 copper nickel or stainless steel, while our evaporator tubes are made with titanium and copper nickel, or duplex stainless steel and aluminum brass. All the piping in our vacuum vapor compression distillers consists of copper nickel, stainless steel or bronze.

  • Aqua-Chem distillers supply high-quality potable and process water to meet critical customer specifications..
  • Distillation can be used in any seawater condition, regardless of salinity, temperature or silt. Distillation produces the most consistent, high-quality water, with less than 5 ppm total dissolved solids (TDS).
  • Aqua-Chem distillers have set the standard for innovations that reduce maintenance costs and downtime, while increasing operating life. We have units that continue to provide excellent service after more than 30 years of operation. Over the years, continual improvements have solidified our reputation as the most innovative designer of offshore desalination equipment.
  • All Aqua-Chem vacuum vapor compression distillers use our patented Spray-Film evaporator design which provides improved wetting of the tube bundle and reduced scaling compared to rising film or plate-type designs. This results in less downtime for cleaning. The Spray-Film design also includes built-in on-line cleaning for removing scale, thus avoiding any disassembly or manual cleaning.
  • Aqua-Chem distillers offer improved safety and ease of maintenance with all major components readily accessible from the deck level. The compressor and pumps are specifically located at the edge of the skid for easy serviceability, encouraging regular maintenance and ensuring a long operating life.
How Aqua-Chem Spray-Film® Vacuum Vapor Compression Works

Incoming feedwater is preheated by the outgoing blowdown and distillate. Feedwater and recirculation water are combined and sprayed over the evaporator tube bundle. Start-up/ make-up steam is produced in the evaporator boiler. A portion of the spray is evaporated as pure steam and the remainder is collected in the sump to be further recirculated. Some of the collected water is discharged as blowdown to maintain the desired brine concentration. Steam generated inside the evaporator is drawn through the demisters by the centrifugal compressor, and is superheated to 250° F in the compression process. The steam condenses inside the evaporator tube bundle and is collected as pure distillate. The distillate is pumped through the heat exchanger and into storage. Vapor compression is significantly more energy efficient than other distillation methods because energy is recycled back into the process.

Equipment Characteristics
Model Capacity
Dimensions (Inches) Weight
Length Width Height
SV30 30 87 116 115 10,000
SV50 50 87 116 115 15,000
SV70 70 87 140 115 18,000


Aqua-Chem is well known in the marine industry for supplying seawater distillers that use waste heat from diesel engine jacket water or other sources to desalinate seawater. In many cases, this wasted energy can be used to make water with little or no additional energy input. Our waste heat units are in service on offshore oil rigs, naval vessels and merchant ships, and have provided years of efficient service. These units consistently produce purified water with less than 5 ppm of total dissolved solids.

Design Features

Heat Source – Diesel engine jacket cooling water is used to supply heat to the unit. Use of waste heat requires little or no additional energy input. If necessary, supplemental steam or electric heat can be provided to compensate for insufficient heat during low engine load operations.

Materials of Construction – We use corrosion-resistant duplex stainless steel, copper-nickel and stainless steel for the shell and piping, and titanium plate packs for the heat exchanger.

Automation – Watermakers are designed for simplicity of operation. Units are controlled by manual startup and shutdown with automatic operation. Product water is continuously monitored with automatic diversion if salinity exceeds programmed limits.

Electricals – ATEX, IEC and CE designs. Accessories/Options – Remineralizers, hydrophores, UV sterilizers, booster pumps, electric heaters and other options are available on request.

  • Compact units with simple operation, only one pump is required to operate.
  • Use of waste heat requires little or no additional energy input.
  • Low-temperature operation reduces corrosion and scaling potential.
  • Custom engineering is available to meet international electrical codes, rig specifications and unique operating conditions.
  • Unit operates automatically after startup with minimal supervision.
  • Easy, low-cost installation, with only five piping connections and one electrical connection.
  • Reliable and durable materials with proven performance after more than four decades of offshore use by Aqua-Chem.
  • DNV/ABS/NR-13 compliance.
  • Double-effect watermakers are also available when waste heat availability is limited.
  • Factory tested to ensure trouble-free startup.
How Aqua-Chem Seawater Plate Distillers Work
  • Seawater first passes through the condenser on one side of each plate in the upper plate pack. It condenses the water vapor into distilled water on the other side of each plate.
  • About 10 percent of incoming seawater is then diverted to the evaporator or lower plate pack of the distiller.
  • The heating water from the waste heat source passes through the evaporator and heats the seawater to boiling. Since the unit operates at a vacuum, the seawater boils at 50° C to 60° C.
  • The water vapor rises toward the top of the unit and passes through a wire mesh mist eliminator before entering the upper plate pack and condensing into distilled water.
  • Distilled water collected in the upper plate pack drains to the distillate pump. Before being pumped to the storage tank, the conductivity is continuously monitored and automatically dumps to drain if the conductivity is too high.
  • The bulk of the seawater flows through the eductor. The seawater drives this suction device which draws vacuum, removes air and gases from the water vapor, and removes concentrated seawater from the bottom of the distiller.
Equipment Characteristics
Model Capacity
Dimensions (mm) Weight
Length Width Height
Single Effect (two plate packs)
SPD13-10 10 350 1,100 1,300 1,600 500
SPD13-25 25 750 1,400 1,300 1,600 550
SPD22-30 30 1,050 1,200 1,600 1,700 1,000
SPD35-40 40 1,400 1,700 1,600 2,400 1,400
SPD35-50 50 1,750 1,700 1,600 2,400 1,500
SPD35-60 60 2,100 2,000 1,600 2,400 1,900
Double Effect (two plate packs)
SPD235-40 40 1,000 2,400 1,800 3,200 2,700
SPD235-60 60 1,400 2,800 1,800 3,200 2,900


Aqua-Chem provides a full range of reverse osmosis systems for offshore oil, gas and drilling customers. Our systems have provided potable water for more than 20 years and are in service around the world. Each reverse osmosis system affords low initial cost and economical life-cycle operating costs.

Design Features
  • Sized to fit in minimum space. Modular, 2 and 3 piece options available to facilitate installation.
  • Robust skid & frame. Can be turned on end to pass through vertical hatch openings. Top side lifting lugs. Frames coated for offshore service.
  • PLC Control of start-up, backwash, shutdown and alarm sequences of operation
  • Automatic freshwater flush at shutdown
  • Design includes automatic back-washable media filters to minimize operating cost
  • Cartridge filters for final filtration
  • Membrane cleaning system included
  • Long-lasting, efficient, positive displacement pump for RO pressure
  • Top quality instrumentation and PLC mounted in NEMA-4X panel
  • Motor starters and high voltage in separate NEMA-4X box
  • Conservative membrane array using proven TFC elements
  • Field proven design. Models in service for over 10 years.
How Aqua-Chem Reverse Osmosis Works

Desalination by Reverse Osmosis (RO) is a process whereby fresh water is extracted from seawater through the use of a semipermeable membrane. An RO watermaker consists of several key components. Prefiltration removes particulate matter from the seawater. Then, a high-pressure pump pressurizes the seawater to approximately 800-1,000 psi. Pressure vessels house the RO membranes where the separation of fresh water from seawater occurs. Approximately 40 percent of the seawater feed is extracted as fresh product. The balance of the water, referred to as “concentrate,” is discharged to drain. A real-time conductivity instrument measures the conductivity of the product water. If the maximum conductivity limit is exceeded, product water is automatically diverted to waste.

Equipment Characteristics
Tons / Day US Gallons
Per Day
Membranes Pressure
30 7,926 25 2 1
50 13,210 30 4 2
60 15,852 34 4 2
80 21,136 35 6 3
100 26,420 35 8 4
120 31,704 39 10 4


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