Abstract: A vertical electrostatic coalescer comprises a first and second electrode surface and a horizontally disposed foraminous surface. The first electrode surface and horizontally disposed foraminous surface are at ground potential. The first and second electrode surfaces share the same planar orientation relative to the central longitudinal axis of the vessel. The unique arrangement of the vessel and opposing pairs of first and second electrode surfaces provides for a substantially uniform voltage field around a perimeter of the vessel and an effective voltage field for coalescence within a center of the vessel. A circular-shaped distributor pipe or a distributor housing serves to absorb momentum of the incoming emulsion stream and distribute the stream into an interior of the vessel.

Abstract: A method of removing entrained salt containing water from an inlet crude oil stream includes the steps of applying an electrical energy to at least one electrode of a plurality of horizontally oriented, spaced-apart electrodes (12, 14, 16) housed within an elongated desalting vessel (10) and distributing an inlet crude oil stream between the electrodes. Each electrode in the plurality of electrodes is housed in an upper portion of the desalting vessel and may be in communication with a first, second and third transformer (42, 44, 46), respectively. The electrical energy may be at a single frequency and voltage or at a modulated voltage. Or, the electrical energy may be a modulated frequency at a single or modulated voltage. Fresh water may be mixed with the inlet crude oil stream either exteriorly or interiorly of the vessel.