Multiple frequency electrostatic coalescence
AssigneeNational Tank Company
InventorGary W. Sams
Life of this patent
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Abstract
A method of augmenting the separation of immiscible heavier and lighter components of an emulsion including the steps of conducting the emulsion into a treatment vessel, providing an AC voltage source, employing from the source an AC voltage of at least one selected frequency F1 to establish at least one electric filed within the vessel through which the emulsion passes, and cyclically modulating the AC voltage with a method of modulation selected from: (a) amplitude modulation; (b) frequency modulation; and (c) combined amplitude and frequency modulation.
Claims35
A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:
- conducting the emulsion into a treatment vessel;
- providing an AC voltage source of readily selectable frequencies;
- employing from said source an AC voltage of a base frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency of F1 at a modulation frequency F2.
A method of coalescing water in a water/oil emulsion comprising:
- providing an AC voltage source;
- 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 an electrical ground potential;
- providing spaced apart electrodes in the vessel above said water level;
- passing the emulsion upwardly between said electrodes;
- employing from said AC voltage source a base frequency F1;
- half wave rectifying said AC voltage to obtain a rectified voltage source of a first polarity that is applied to one of said electrodes;
- half wave rectifying said AC voltage 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;
- cyclically modulating the frequency of F1 at a modulation frequency 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 desalting a liquid hydrocarbon comprising:
- providing an AC voltage source;
- 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, employing from said AC voltage source an AC voltage of base frequency F1;
- applying said AC voltage of frequency F1 to said electrodes to thereby establish an electric field between adjacent electrodes;
- cyclically modulating the frequency of F1 at a modulation frequency 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;
- determining the threshold voltage of the emulsion;
- conducting the emulsion into a treatment vessel;
- employing from said AC voltage source an AC voltage of base frequency F1;
- employing said AC voltage of frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency F1 of said AC voltage at a modulation frequency F2, wherein the minimum voltage employed 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;
- determining at least some of the physical characteristics of the emulsion;
- conducting the emulsion into a treatment vessel;
- employing from said AC voltage source a base frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency of F1 at a modulation frequency 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;
- passing the emulsion into a treatment vessel;
- employing an AC voltage from said source of base 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
- cyclically modulating the frequency F1 of said AC voltage at a selected modulation 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;
- conducting the emulsion into a treatment vessel;
- employing from said AC voltage source a base frequency F1;
- employing said voltage of base frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency of said base frequency F1 at a selected modulation frequency F2 wherein F1 is greater than F2, 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;
- measuring the interfacial tension of the emulsion;
- conducting the emulsion into a treatment vessel;
- employing AC voltage of base frequency F1 from said AC voltage source to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency of said AC voltage of base frequency F1 at a selected modulation frequency F2 wherein F1 is greater than F2, and wherein F2 is determined essentially by the measured interfacial tension.
A method of augmenting the separation of immiscible heavier and lighter components of an emulsion comprising:
- conducting the emulsion into a treatment vessel;
- providing an AC voltage source;
- employing from said source an AC voltage of at least one base frequency F1 to establish at least one electric field within said vessel through which the emulsion passes;
- and
- cyclically modulating the frequency F1 of said AC voltage at a modulation frequency F2.
Dependencies are inferred from the claim text.