The oil extracted from oilfield, always have some dissolved salts in waters. The most common salts in the oil are Calcium, Sodium, Magnesium and Chloride salts. The presence of water and salt in crude oil will cause many operational problems such as corrosion, blockage of pipelines, etc. The first equipment after separation of oil and gas is desalter. Desalter is an equipment that water and therefore inorganic salts of crude oil would be separated by that.