Solvent dewaxing process

In a process for dewaxing a waxy lubricating oil stock by cooling said stock in the presence of a dewaxing solvent to a temperature effective for the removal of wax therefrom by filtration the improvement which comprises introducing said oil stock into a chilling zone into countercurrent liquid-liquid contact with a chilled immiscible heat exchange liquid, separating said heat exchange liquid from resulting chilled oil stock, introducing dewaxing solvent into admixture with said chilled oil stock at substantially dewaxing temperature, separating by filtration solidified wax from resulting dewaxed oil and solvent, recovering a mixture of solvent and oil of diminished wax content from said filtration step, and passing said dewaxed oil/solvent mixture at substantially said dewaxing temperature into intimate countercurrent liquid-liquid contact with immiscible liquid coolant from said cooling zone thereby chilling said heat exchange liquid for reuse in said cooling zone and warming said mixture of dewaxed oil and solvent, separating said warmed dewaxed oil and solvent from said heat exchange liquid, chilling said heat exchange liquid to substantially dewaxing temperature and reintroducing said chilled heat exchange liquid into said cooling zone.