Dewaxing process

Claim 1

A METHOD OF DEWAXING A WAX-BEARING OIL STOCK COMPRISING MIXING THE WAX-BEARING OIL WITH A DEWAXING SOLVENT, CHILLING THE SOLUTION THUS OBTAINED TO A TEMPERATURE SUFFICIENTLY LOW TO PRECIPITATET A SUBSTANTIAL PORTION OF THE WAX CONTAINED THEREIN, FILTERING THE RESULTING MIXTURE IN A FIRST FILTERING ZONE TO REMOVE THE PRECIPITATED WAX AS A FIRST FILTER CAKE AND TO PRODUCE A DEWAXED FILTRATE, ADMIXING SAID FILTER CAKE WITH COOLED SOLVENT AND PASSING THE ADMIXTURE THUS OBTAINED INTO A SECOND FILTERING ZONE TO PRODUCE A SECOND FILTER CAKE AND A DEWAXED FILTRATE, RECOVERING THE RETAINED SOLVENT FROM SAID SECOND FILTER CAKE THE THUS RECOVERED SOLVENT CONTAINING A SMALL AMOUNT OF LIGHT WAX, MIXING WITH SAID RECOVERED SOLVENT A POUR POINT DEPRESSANT IN SUCH AMOUNT AS TO SUBSTANTIALLY PREVENT THE PRECIPITATION OF SAID LIGHT WAX WHEN COOLING SAID RECOVERED SOLVENT TO A DESIRABLE TEMPERATURE, PASSING THE RESULTING MIXTURE OF RECOVERED SOLVENT AND POUR POINT DEPRESSANT INTO HEAT EXCHANGING RELATIONSHIP WITH A COOLING MEDIUM TO COOL SAID RECOVERED SOLVENT TO A TEMPERATURE LOWER THAN THAT PREVIOUSLY OBTAINABLE WITHOUT THE ADDITION OF SAID POUR POINT DEPRESSANT DUE TO THE PRECIPITATION OF SAID LIGHT WAX, AND RECYCLING THE THUS COOLED SOLVENT DIRECTLY TO THE STEP OF ADMIXING SAID FIRST FILTER CAKE WITH COOLED SOLVENT.

Claim 2

A METHOD OF DEWAXING A WAX-BEARING OIL STOCK COMPRISING MIXING THE WAX-BEARING OIL WITH A DEWAXING SOLVENT, CHILLING THE SOLUTION THUS OBTAINED TO A TEMPERATURE SUFFICIENTLY LOW TO PRECIPITATET A SUBSTANTIAL PORTION OF THE WAX CONTAINED THEREIN, FILTERING THE RESULTING MIXTURE IN A FIRST FILTERING ZONE TO REMOVE THE PRECIPITATED WAX AS A FIRST FILTER CAKE AND TO PRODUCE A DEWAXED FILTRATE, ADMIXING SAID FILTER CAKE WITH COOLED SOLVENT AND PASSING THE ADMIXTURE THUS OBTAINED INTO A SECOND FILTERING ZONE TO PRODUCE A SECOND FILTER CAKE AND A DEWAXED FILTRATE, RECOVERING THE RETAINED SOLVENT FROM SAID SECOND FILTER CAKE THE THUS RECOVERED SOLVENT CONTAINING A SMALL AMOUNT OF LIGHT WAX, MIXING WITH SAID RECOVERED SOLVENT A POUR POINT DEPRESSANT IN SUCH AMOUNT AS TO SUBSTANTIALLY PREVENT THE PRECIPITATION OF SAID LIGHT WAX WHEN COOLING SAID RECOVERED SOLVENT TO A DESIRABLE TEMPERATURE, PASSING THE RESULTING MIXTURE OF RECOVERED SOLVENT AND POUR POINT DEPRESSANT INTO HEAT EXCHANGING RELATIONSHIP WITH A COOLING MEDIUM TO COOL SAID RECOVERED SOLVENT TO A TEMPERATURE LOWER THAN THAT PREVIOUSLY OBTAINABLE WITHOUT THE ADDITION OF SAID POUR POINT DEPRESSANT DUE TO THE PRECIPITATION OF SAID LIGHT WAX, AND RECYCLING THE THUS COOLED SOLVENT DIRECTLY TO THE STEP OF ADMIXING SAID FIRST FILTER CAKE WITH COOLED SOLVENT.