**1.4 The salts in crude oil**

The salts and minerals often present in the oil are mainly magnesium, calcium, and sodium chlorides with sodium chloride being the abundant type. These salts cause corrosion of equipment. For example, hydrogen chloride (HCl). Hydrogen chloride dissolves in the emulsion's water producing hydrochloric acid, an extremely corrosive acid. However, NaCl = Na<sup>+</sup> + Cl�. Water, though slight, but dissociates into ions, and the equilibrium is established: H2O=H+ +OH�, thus, in the salt solution, there is a mixture of Na<sup>+</sup> cations and OH�, Cl�anions. Ions in the solution move randomly and constantly collide with each other [21]. But these collisions of Na<sup>+</sup> and OH� ions, H+ and Cl� ions do not lead to the formation of compounds, since NaOH is a strong base, and HCl is a strong acid. Since weak electrolytes are not formed when sodium chloride is dissolved in water, sodium chloride is not hydrolyzed. The concentration of H+ ions is equal to the concentration of OH� ions, so the color of the indicators does not change [13, 20]. All chemical compounds based on chlorine hydrolyze, except for NaCl, hydrolyze at high temperature to hydrogen chloride:

$$\text{CaCl}\_2 + 2\text{H}\_2\text{O} \rightarrow \text{Ca(OH)}\_2 + 2\text{HCl} \tag{1}$$

$$\text{MgCl}\_2 + 2\text{H}\_2\text{O} \rightarrow \text{Mg(OH)}\_2 + 2\text{HCl} \tag{2}$$

Any remaining salts are neutralized by the injection of sodium hydroxide which reacts with the calcium and magnesium chloride to produce sodium chloride because NaCl does not hydrolyze to the corrosive hydrogen chloride.

$$\text{CaCl}\_2 + 2\text{NaOH} \rightarrow \text{Ca(OH)}\_2 + 2\text{NaCl} \tag{3}$$

#### **1.5 Description of dewatering of oil emulsions with electrostatic desalter**

The electrical conductivity of oil emulsions is due to the ionic conductivity of oil, the conductivity of dispersed water droplets in oil. Under certain conditions, droplets of emulsified water in oil form conductive structures in the form of "chains", located along the field lines [12, 22]. The electrical conductivity of the system in such cases increases sharply (hundreds and thousands of times) in comparison with the electrical conductivity of anhydrous oil. Electrical Conductivity of hydrocarbons (oil), the hydrocarbons have three types of conductivity regimes in general [23]:

