Continuous dewaxing of oil - by direct contact with boiling refrigerant opt with dewaxing solvent

摘要

Continuous dewaxing of a petroleum oil, e.g. a lube oil of boiling range 400 - 1500 degrees F, opt. with a dewaxing solvent, by introducing the oil into a multi-stage chilling vessel, introducing a liq refrigerant incrementally along the length of the vessel into at least some of the stages, maintaining agitation in the vessel so that oil and refrigerant mix instantaneously, maintaining the pressure in each stage so that at least some of the refrigerant vaporises on contact with the oil thereby cooling it and pptg at least some of the wax, and removing a slurry of oil and wax from the vessel. The refrigerant is pref a 2-4C hydrocarbon and the oil is pref cooled at 1 - 10 degrees F/min. When a dewaxing solvent is used it is pref a 3-6C ketone with or without an aromatic.