Patent ID: 6228239
Filing Date: 2001-05-08
Classification: C10G

Abstract:
A method for removing a brine of salt and water from a crude oil, the method comprising:(a) adding to the crude oil a chemical demulsifier formulation, the chemical demulsifier formulation being present in an amount ranging from about 1 ppm to about 1,000 ppm based on the weight of the crude oil;(b) adding wash water to the crude oil and chemical demulsifier formulation in an amount ranging from about 0.5 vol. % to about 3.0 vol. %, provided that no wash water is added when the concentration of the brine in the crude oil is greater than about 3.0 vol. % being based on the total volume of the crude oil; and(c) separating the brine from the crude oil and chemical demulsifier formulation under electrostatic desalting conditions at a temperature ranging from about 220.degree. F. to about 300.degree. F., at an electrostatic potential ranging from about 500 to about 5000 volts per inch and for a time ranging from about 1 to about 30 minuteswherein the chemical demulsifier formulation contains about 35 wt. % to about 75 wt. % of at least one delivery solvent selected from the group consisting of dipropylene monobutyl ether, isoparaffinic solvent, cycloparaffinic solvent, diethylene glycol monobutyl ether, benzyl alcohol; about 5 wt. % to about 15 wt. of heavy aromatic naphtha; and a chemical emulsion breaker present in an amount ranging from about 10 wt. % to about 60 wt. % and having a formula: ##STR4##x ranges from 1 to 5, y ranges from 0 to 2, R is an alkyl group having 4 to 9 carbon atoms, and n ranges from 3 to 9;all wt. % being based on the weight of the chemical demulsifier formulation.