Solvent dewaxing process

Claim 1

IN A CONTINUOUS METHOD FOR THE LOW TEMPERATURE DEWAXING OF A PARAFFINIC LUBRICATING OIL FRACTION WHEREIN A SOLVENT IS EMPLOYED, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF MIXING THE FEED STOCK WITH FRESH SOLVENT, CHILLING THE MIXTURE TO A TEMPERATURE SUFFICIENT TO FORM AN INITIAL SLURRY OF CRYSTALLIZED OIL-CONTAINING WAX IN A MOTHER LIQUOR COMPRISED OF DEWAXED OIL AND SOLVENT, PASSING THE RESULTANT SLURRY THROUGH A FIRST TURBULENT ISOTHERMAL FILTRATION ZONE AND TURBULENTLY ISOTHERMALLY REMOVING FROM ABOUT 20 TO 60 VOLUME PERCENT OF SAID MOTHER LIQUOR CONTAINED THEREIN TO PROVIDE A FIRST FILTRATE FRACTION AND A FIRST CONCENTRATED SLURRY FRACTION, RECOVERING DEWAXED OIL FROM SAID FIRST FILTRATE FRACTION, ADDING TO SAID FIRST CONCENTRATED SLURRY FRACTION AN AMOUNT OF FRESH SOLVENT SUBSTANTIALLY EQUIVALENT TO THE AMOUNT OF MOTHER LIQUOR RECOVERED FROM SAID FIRST FILTRATE FRACTION TO THEREBY FORM A DILUTED FIRST SLURRY, HEATING SAID DILUTED FIRST SLURRY TO A TEMPERATURE GREATER THAN THAT OF SAID FIRST TURBULENT ISOTHERMAL FILTRATION ZONE, PASSING SAID HEATED FIRST SLURRY THROUGH AT LEAST A SECOND TURBULENT ISOTHERMAL FILTRATION ZONE AND TURBULENTLY ISOTHERMALLY REMOVING FROM ABOUT 20 TO 60 VOLUME PERCENT OF THE MOTHER LIQUOR THEREFROM TO PROVIDE A SECOND FILTRATE FRACTION AND A SECOND CONCENTRATED SLURRY FRACTION AND RECOVERING FROM SAID SECOND FILTRATE FRACTION A DEWAXED OIL HAVING A POUR POINT GREATER THAN THE POUR POINT OF THE DEWAXED OIL RECOVERED FROM SAID FIRST FILTRATE FRACTION.