Abstract: An improved process for the solvent dewaxing of petroleum oil stocks. Wax-containing oil is chilled in an elongated chilling zone by introducing cold dewaxing solvent into said zone, at a plurality of points along same, said chilling zone containing or having associated with it a plurality of static means for mixing the solvent and wax-containing oil under conditions of plug flow radial mixing, thereby avoiding shock chilling without the need for the intense agitation and/or dynamic agitators normally required for such processes.

Abstract: An improved dilution chilling dewaxing process for waxy petroleum oils wherein the dewaxed oil yield is increased and the solvent recovery requirements are decreased by recycling solvent-rich wash filtrate from the first stage wax filters back into the dilution chilling dewaxing zone.

Abstract: Ketone dewaxing solvent is separated and recovered from dewaxed oil and a wax slurry through the use of flash vaporization or distillation followed by steam stripping. Water is removed from the recovered solvent through the use of a combination of a decanting drum to form a solvent phase and a water phase, a deketonizer tower which strips solvent from the water phase, and a simple distillation tower which functions as a solvent dehydrator. It has been found that feeding a portion of the overhead vapors from the flash vaporization step directly to the bottom of the dehydrator provides enough heat to eliminate the need for a reboiler on the dehydrator tower.