Patent ID: 8986536
Filing Date: 2015-03-24
Classification: B01D,C10M

Abstract:
1. A method for recovery of spent lubricating oil, the method comprising steps of: passing the spent lubricating oil having ambient temperature and a pressure ranging between 150 to 1030 mbar through a first evaporator having a first heating device for heating the spent lubricating oil to a temperature ranging between 70° C. to 240° C., thereby forming vapours of light hydrocarbons, water, and/or ethylene glycol from the spent lubricating oil; condensing vapours received from the first evaporator in a first condenser; separating vapours and liquid from the vapours received from the first condenser in a first separator; compressing the vapours from the first separator in a first compressor; passing the spent lubricating oil pumped from the first evaporator having a temperature ranging between 70° C. to 240° C. through a second evaporator at a pressure ranging between 6 to 30 mbar and having a second heating device for heating the spent lubricating oil to a temperature ranging between 200° C. to 290° C., thereby forming vapours of light vacuum gasoil from the spent lubricating oil; condensing the vapours received from the second evaporator in a second condenser; separating vapours and liquid from the condensed vapours received from the second condenser in a second separator; compressing the vapours received from the second separator in a second compressor; passing the spent lubricating oil pumped from the second evaporator having a temperature ranging between 200° C. to 290° C. through a third evaporator at a pressure ranging between 0.5 to 15 mbar having a third heating device for heating the spent lubricating oil to a temperature ranging between 250° C. to 320° C., thereby forming vapours of heavy gasoil from the spent lubricating oil; condensing the vapours received from the third evaporator in a third condenser; separating vapours and liquid from the condensed vapours received from the third condenser in a third separator; compressing the vapours received from the third separator in the third compressor, thereby recovering the spent lubricating oil; wherein one or more of the first, second, and third heating devices include heat transfer tubes arranged vertically, whereby oil is distributed to the heat transfer tubes to form a flowing liquid film over a surface of the heat transfer tubes.