Neda Neisi - NISOC (National Iranian South Oil Company
Salem Banooni - Department of Mechanical Engineering, Shahid Chamran university, Ahwaz, Iran

In most of wells, produced oil contain water and dissolved salts, mainly NaCl, CaCl2 and MgCl2,which cause several problems in the refining processes. Maximum allowable water content in theoutlet crude oil has been limited up to 0.1% volume and salt content up to 10 pounds in thousandbarrels, So dilution water mixes with crude oil to reduce salinity of crude oil. At first, dilution water mixes with formation water, then it removes from crude oil. The injection rate of dilutionwater is usually between 3 to 7 percent of the inlet crude oil. In this research, a two stagesdesalting plant is modelled and reveals, by 100 ppm increasing salinity of the dilution water (from 700 to 1500 ppm), the amount of dilution water rises 25.39 barrel per day which means by reducing salinity of dilution water, the required dilution water decreased

crude oil desalting, two stage desalting, dilution water, salinity