Evaporators

Main principle EWS evaporator

When seawater is boiled in a vacuum chamber, vapour can be produced at temperatures as low as 40°C. It is this principle of low temperature/low pressure distillation, which is applied in the evaporator for the production of fresh water from seawater. It utilizes a source of low-grade heat, mostly waste heat from diesel engines, to produce the vapour.

In the evaporator a controlled amount of seawater is supplied as feed water, to the bottom of the heat exchanger. Here the seawater is heated in a vacuum and evaporated. The remaining non-evaporated seawater is discharged continuously in order to control the brine density. The evaporator uses the rejected heat from the fresh water-cooling system of the ship's engines. This hot jacket water, which may reach a temperature between 75°C and 90°C, is passed outside the tubes of the heat exchanger.
Depending on the amount of cooling water, as it passes through, the temperature will drop between 3°C and 14°C, before returning to the ship's system.

The evaporators, marketed under the EWS banner, are compact, suitable for bulkhead or stand-alone installations. Combined with a UV sterilizer, the quality of the fresh drinking water produced, meets the high standards set by of the World Health Organisation (WHO).

The installation contains:

The stainless steel EWS evaporators are standard provided with:

  • Ejector pump
  • Fresh water pump
  • Salinity indicator
  • Internal piping
  • Gauges
  • Thermometers
  • Ejectors
  • Colour of your choice without extra costs (standard colour light blue)
  • Electric panel, motor starters and wiring
 
EWS 0,5
  
EWS 20

Advantages EWS evaporators

  • Low use of chemicals
  • No demister needed
  • Unaffected roll and pitch
  • No coating (RVS 316L body evaporator chamber)
  • Low maintenance costs

Accessories EWS evaporators

  • Steam injector
  • UV disinfection unit
  • Silver ions disinfection unit
  • Neutralising filter
  • Extra connection for heater
  • Thermal oil connection


Types of Drema evaporators

Bulkhead installation
Type
Capacity
(m3/24h)
Height
(mm)
Depth
(mm)
Width
(mm)
Weight
(kg)
EWS 0,5
Max. 3
1250
570
800
350
EWS 5
Max. 5
1300
650
1100
525
EWS 10
Max. 10
1450
850
1400
750
 
Stand-alone installation
Type
Capacity
(m3/24h)
Height
(mm)
Depth
(mm)
Width
(mm)
Weight
(kg)
EWS 15
Max. 15
2010
1465
1615
1150
EWS 20
Max. 20
2010
1465
1615
1300
EWS 25
Max. 25
2010
1465
1615
1500
EWS 36
Max. 40
2150
1550
2000
1850

On request, all our units can have an accompanying Lloyds, Rina, Veritas, etc., certificate.

Drema Waterbehandeling B.V. also can deliver larger capacities on request.