Patent ID: 7117722

Claim:
A method for desalting oils comprising: a. determining TAN and viscosity of the oil, b. mixing the oil with water to form a water-in-oil emulsion, c. determining viscosity of the water-in-oil emulsion in accordance with the expression: η ( emul ) = K ⁢ ⁢ η ( oil ) ⁢ TAN - r ( 1 - ϕ ) 2.5 wherein η (oil) is the viscosity the oil, TAN is the total acid number of the oil, φ is a number in the range of 0.1 to 0.8, r is a number in the range of about 0.5 to 2, and K is a number from about 1 to 20, said determined value, η (emul) being the viscosity of the water-in-oil emulsion, d. adjusting the TAN of the oil sufficiently to adjust the viscosity of the emulsion, η (emul) , as determined in accordance with step c, to a predetermined value, and e. demulsifying the emulsion.