The present invention relates to an apparatus for separation of hydrocarbons from hydrocarbon-containing produced water, comprising; a separator tank, at least one inlet tube (22, 27), at least one branch means (6) distributing the produced water stream, at least one outlet nozzle (7) and at least one guide vane (8.1) mounted under each outlet nozzle and leading water over the next outlet nozzle; at least one outlet (12) in the bottom of the tank for cleaned water and at least one outlet (9, 35, 36) rejecting rising gas with adherent oil droplets, at least one shroud (39) is arranged entirely or partly along the inside of at least one guide vane (8.1) in an angle of 30° to 150° related to the at least one guide vane (8.1). Further the invention relates to a process for separation of hydrocarbons from hydrocarbon-containing produced water.