Disclosed is an apparatus and process for controlling the sulfur content of effluent from a hydrocarbon fractionation column. The effluent includes a low boiling stream, a middle boiling stream and a high boiling stream. Either of the feed or the low boiling stream may be subjected to a mercaptan removal treatment such as thioetherification or mercaptan oxidation treatment. The high boiling stream is subjected to hydrotreatment which will rid the high boiling stream of almost all organic sulfur compounds. The middle boiling stream may be subjected to a sulfur treatment complex which may comprise a sulfur removal unit and/or a catalytic reforming unit which may already be present in the refinery. Control valves govern the flow of adding the middle boiling stream to the low boiling stream and the high boiling stream in response to the sulfur concentration of the overhead stream downstream of the mercaptan removal treatment.