Abstract: A process and apparatus for dewatering a recovered oil stream prior to the recovered oil stream being fed to a fractionator for reprocessing into product s rea s uses a blowdown drum controlled like a drstillatron tower so that the bottoms temperature of the blowdown drum is maintained at a temperature above the dewpoint temperature of the water in the blowdown drum by a reboiler. For refineries that contain a delayed coker unit and a coker fractionator which is used for fractionating light products from residual oil serving as coker feedstock, which coker fractionator is also used to fractionate recovered oil containing water and hydrocarbons, a coker blowdown drum is controlled to maintain an appropriate bottoms temperature to achieve separation in the blowdown drum of water from the hydrocarbons in the recovered oil stream, and the blowdown drum is thus used for dewatering the recovered oil before it is fed to the coker fractionator.