Atmospheric andvacuumdistillationdeviceisthe first proces-
sing unitinarefinery.Electricdesaltingisthe first procedurefor
the atmosphericandvacuumdistillationofcrudeoil.Thispre-
treatment processisnecessarytoprovidequalified crudeoilfor
downstreamunits.Oilconcentrationineffluent electricdesalting
wastewater(EDW)shouldgenerallymeettherequirementof
below 200mg/L.Electricdesaltingdeviceshaverecentlybecome
increasinglydifficult tooperatebecauseoftheaggravatingtrendof
heavieranddeterioratedcrudeoil