Comparing of reverse osmosis and MED technique for producing of desalinated water from sea water

Two plants for producing of desalinated water from Persian Gulf; Ro and MED existing in MOBIN PETROCHEMICAL COMPANY situated in ASSALUYEH is compared economically, In RO plant, 500 m3/day of desalinated water with 150 ppm of TDS is produced while in MED plant, it is produced 38,000 m3/day with 5 ppm of TDS from seawater with 45,000 ppm of TDS. If the ion exchange treatment be added to further treatment of membrane technique to produce desalinated water with 5 ppm of TDS, it is concluded, for producing of 1 m3/day of desalinated water with 5 ppm of TDS, Construction cost is 1,000-1,500 $ for RO and MED, investment cost is 1,600 $ for RO and MED, power consumption is 3.5 kwh for RO and 2.5 kwh for MED, chemical consumption cost is 0.03 $ for RO and 0.04 $ for MED, labor cost is 0.03 $ for RO and 0.02 $ for MED, maintenance cost is %2/year of investment cost for RO and %1/year of investment cost for MED and finally 20% of membrane should be exchanged in every year in membrane plant and in MED plant, steam consumption is 125 kg/m3 of desalinated water.It is concluded, in a situation with steam available, a perfect technique for desalinating of sea water is MED.

Keywords:

Desalination , MED , RO