Abstract: A compact desalting system for use in a process of desalting crude oil comprises a plurality of separation stages. Each separation stage includes a compact electrostatic coalescer (42, 62) for coalescing water droplets carried with the crude oil and settling means (91, 92; 95, 96) for settling separated oil and coalesced water droplets. The system includes a vessel (46) comprising a plurality of compartments containing the settling means and the compact electrostatic coalescers are each mounted in a housing on top of the vessel.

Abstract: A method of separating oil and water in a flow-stream through a gravity settling vessel (10) in which the flow-stream (12) separates into a lower water layer (22) and an upper oil layer (26), includes feeding an off-take stream (34) of the oil layer and/or an emulsion layer (20) that forms between the oil layer and the water layer through a compact electrostatic coalescer (CEC) (38) that has electrically isolated electrodes. The CEC coalesces water droplets in the off-take stream, and the coalesced off-take stream is then returned to the settling vessel. An associated separator apparatus for comprises: a gravity settling vessel (10); a CEC (38) including electrically isolated electrodes; a coalescer feed line (34) configured to provide an off-take stream of an oil phase and/or an emulsion layer from the settling vessel to the CEC; and a return line (40) from the CEC for returning the off-take stream to the settling vessel.