Desalination
Sep-Pro Systems designs and manufactures two types of desalination units.
- Multi-effect evaporators for seawater or brines
- Reverse Osmosis for seawater desalination
The multi-effect evaporators are used to concentrate and reduce the volume of oil field produced water by producing distilled water. A different design is used for seawater desalination. Waste heat from engine, gas turbine exhaust, or other sources is usually used. The use of high priced energy is usually not justified. 75% of oilfield brine volume can be distilled to potable water depending on concentration. Multi-effect evaporation is cost effective using four to six effects when waste heat is available. Brackish water is more treatable with multi-effect evaporators than reverse osmosis because of unpredictable TDS composition and concentration. MEE is more expensive than reverse osmosis for conventional seawater desalination.
Reverse osmosis is typically used for seawater desalination and for predictable process separations i.e. cooling tower make-up, food process separations. Overcoming the osmotic pressure and hydraulic resistance can require pressure from 700-900 psig. For seawater desalination typically a 30-40% permeate (potable water) recovery is possible. The RO membranes are very susceptible to fouling and multi-media filters or ultra filtration is usually required. Periodic membrane flushing is necessary. Reverse osmosis to treat produced water from oil field is not recommended.
Sep-Prop Systems designs the necessary feed water intake, pretreatment filter, reverse osmosis or mutli-effect evaporator and concentrate disposal systems. |
