Dual frequency electrostatic coalescence

A method of desalting a liquid hydrocarbon comprising:

• providing an AC voltage source of readily selectable frequency:
• flowing salty hydrocarbon into a portion of a vessel;
• providing a plurality of substantially paralleled spaced apart electrodes within said vessel;
• in response to the characteristics of the liquid hydrocarbon, selecting from said AC voltage source a selected frequency F1;
• applying said selected frequency F1 to said electrodes to thereby establish an electric field between adjacent electrodes, and modulating said selected frequency in amplitude at frequency F2 where F1 is greater than F2;
• conducting said salty hydrocarbon between adjacent of said electrodes;
• flowing fresh water into said vessel between adjacent said electrodes counter current to the flow of said hydrocarbon;
• withdrawing water from a portion of said vessel;
• and
• withdrawing reduced salty hydrocarbon from a portion of said vessel.

A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• introducing the emulsion into at least one distribution conduit submerged within liquid within an interior of a vessel;
• passing emulsion within each said distribution conduit into aid vessel through a plurality of small dimensioned openings to provide a plurality of small streams;
• rapidly attenuating the momentum of said small streams passing into said vessel from said small dimensioned openings to substantially dissipate kinetic energies thereof and to thereby provide substantially turbulence free emulsion movement in said vessel;
• selecting from said AC voltage source a selected frequency F1;
• establishing at least one electric field within said vessel employing said AC voltage source of frequency F1:
• modulating the amplitude of said electric field at a frequency F2 where F1 is greater than F2.

A method of augmenting the coalescence of water in an emulsion having a water component that is relatively electrically conductive and an oil component that is relatively non-conductive comprising:

• providing an AC voltage source of readily selectable frequency;
• tangentially injecting the emulsion into the interior of an electrically conductive cylindrical vessel having an cylindrical sidewall, opposed first and second ends and a vessel cylindrical axis and tangentially withdrawing the emulsion from the vessel interior to cause the emulsion to flow circumferentially within the vessel around the vessel cylindrical axis to thereby impart by the force of fluid flow alone, centrifugal force on the emulsion to create a first area within the vessel adjacent the vessel sidewall to which a heavier component of the emulsion migrates and a second area within the vessel interior adjacent to the vessel cylindrical axis toward which a lighter component migrates;
• selecting from said AC voltage source a selected frequency F1;
• imposing said AC voltage of selected frequency between an elongated conductive central electrode of external diameter less than the internal diameter of the vessel and said cylindrical sidewall, the central electrode extending concentrically along the vessel cylindrical axis;
• and modulating the amplitude of said AC voltage source of frequency F1 at a frequency F2 wherein F1 is greater than F2 to cause at least a portion of the water component of the emulsion to coalescence.

A method of coalescing water in a water/oil emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• passing the emulsion into a vessel in which water is maintained in a lower portion thereof at a preselected water level, the water serving as electrical ground potential;
• providing spaced apart electrodes in the vessel above said water level;
• passing the emulsion upwardly between said electrodes;
• selecting from said AC voltage source a selected frequency F1;
• rectifying said AC voltage of frequency F1 to obtain a rectified voltage source of a first polarity that is applied to one of said electrodes;
• half wave rectifying said AC voltage of frequency F1 to obtain a rectified voltage potential of the opposite polarity that is applied to the other of said electrodes, the voltage potential applied between said electrodes and said water ground potential thereby varying at a frequency F1;
• modulating in amplitude said selected AC voltage of frequency F1 at a frequency F2 where F1 is greater than F2;
• withdrawing water from said vessel lower portion as required to maintain said water level;
• and
• withdrawing emulsion having a reduced water content from an upper portion of said vessel.

A method of augmenting the coalescence of water in a water-in-oil emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• tangentially injecting the emulsion into a cylindrically walled electrically conductive vessel having a cylindrical interior surface and opposed ends to cause the emulsion to flow circumferentially within the vessel around the exterior of a substantially cylindrical tubular electrode extending concentrically within said vessel to thereby cause a heavier component of the emulsion to migrate toward the vessel's cylindrical exterior surface and to maintain a higher percentage of a lighter component within the vessel interior;
• thereafter passing said emulsion axially through an annular area between the interior of said tubular electrode and the exterior of an elongated central electrode extending concentrically within said tubular electrode, the vessel, the tubular electrode and the central electrode being electrically insulate from each other, the emulsion flowing to an outlet within said tubular electrode;
• selecting from said AC voltage source a selected frequency F1;
• rectifying said selected AC voltage of frequency F1 to obtain a first half wave rectified voltage of a first polarity and frequency F1;
• applying said half wave rectified voltage of a first polarity and frequency F1 between said vessel and said tubular electrode;
• rectifying said selected AC voltage of frequency F1 to obtain half wave rectified voltage of an opposite polarity and frequency F1;
• and
• applying said half wave rectified voltage of an opposite polarity between said tubular electrode and said central electrode, said AC voltage of selected frequency F1 being modulated in amplitude at a frequency F2 where F1 is greater than F2.

A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• determining the threshold voltage of the emulsion;
• conducting the emulsion into a treatment vessel;
• selecting from said AC voltage source a selected frequency F1;
• employing said AC voltage of selected frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
• and
• modulating the intensity of said selected AC voltage at a frequency F2 wherein F1 is greater than F2 and wherein the minimum voltage is about 0.8 to 1.2 times the determined threshold voltage.

A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• determining at least some of the physical characteristics of the emulsion;
• conducting the emulsion into a treatment vessel;
• selecting from said AC voltage source a selected frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
• and
• modulating the amplitude of said AC voltage of selected frequency F1 at a selected frequency F2 wherein F1 is greater than F2 and wherein F1 and F2 are separately selected in accordance with determined emulsion physical characteristics.

A method of augmenting the separation of immiscible heavier and lighter components of a conductive emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• passing the emulsion into a treatment vessel,
• employing an AC voltage from said source of selected frequency F1 to establish at least one electric field within said vessel through which the emulsion passes, F1 being selected according to the emulsion conductivity;
• and
• modulating the intensity of said AC voltage at a selected frequency F2 wherein F1 is greater than F2.

A method of augmenting the separation of immiscible heavier and lighter components of an emulsion having droplets of variable mass, comprising;

• providing an AC voltage source of readily selectable frequency;
• conducting the emulsion into a treatment vessel;
• selecting from said AC voltage source a selected frequency F1;
• employing said selected voltage of frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
• and
• modulating the intensity of said selected voltage source of frequency F1 at a selected frequency F2 wherein F1 is greater than F2, and wherein F2 is selected to attain effective growth of droplet mass.

A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:

• providing an AC voltage source of readily selectable frequency;
• measuring the interfacial tension of the emulsion;
• conducting the emulsion into a treatment vessel;
• selecting AC voltage of frequency F1 from said AC voltage to establish at least one electric field within said vessel through which the emulsion passes;
• and
• modulating the intensity of said AC voltage of frequency F1 at a selected frequency F2 wherein F1 is greater than F2, and wherein F2 is determined essentially by the measured interfacial tension.