In this paper performances of single and multiple-effect evaporation (SEE/MEE) mechanical vapor recompression (MVR) systems, for wastewater treatment of the crude oil desalting plants are compared, using ASPEN PLUS software. All the simulated SEE/MEE systems were optimized for feed salinity of 70 g/kg, containing 5000 ppm oil and zero liquid discharge, by allowing the brine salinity discharge to be close to salt saturation conditions (300g/kg). The results showed that the MEE-MVR including thermal integration system has the best performance for desalination of the wastewater, in terms of energy consumption and operational expenditures (OPEX). Sensitivity analysis were carried out on the effect of the feed salinity and salt type in MEE-MVR system. Increasing salinity (NaCl), up to 120 g/kg, resulted in higher energy consumption, however OPEX decreased as salinity increased above 140 g/kg. Waste water containing CaCl2 needed more energy to be treated, compared to water containing NaCl and MgSO4.

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