Abstract: A vessel for treating an oil-in-water inlet stream houses an inlet flow distributor arranged to direct an inlet flow toward a perforated baffle of a coalescing section, the coalescing section housing a packing and being arranged upstream of a second baffle; a flotation section arranged to receive a flow exiting the coalescing section and being divided by one or more perforated baffles; and an outlet water collecting pipe arranged to receive a flow exiting the flotation section, the outlet water collecting pipe having one or more openings located along its length. The coalescing section may be divided into two sections, with one section preferably housing a different pre-selected sized packing than the other section. The flotation section may include one or more gas-inducing devices. A solid baffle may be arranged downstream of the second baffle and ahead of the flotation section to provide single or dual flow through that section.

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.