Method for distilling oils

Claim 1

THE METHOD OF SEPARATING A HYDROCARBON MIXTURE BY FRACTIONAL DISTILLATION WHICH COMPRISES, HEATING THE MIXTURE AND PASSING IT TO A PRIMARY FRACTIONATION COLUMN TO OBTAIN A LIGHT DISTILLATE AND A BOTTOMS UNDER CONDITIONS WHICH INCOMPLETELY REMOVE FROM THE BOTTOMS, MATERIALS BOILING WITHIN THE RANGE OF THE LIGHT DISTILLATE, WITHDRAWING THE LIGHT DISTILLATE AS AN OVERHEAD FROM SAID COLUMN, WITHDRAWING AN INTERMEDIATE SIDE STREAM OF CONTROLLED END POINT FROM SAID COLUMN, STRIPPING THE REMAINDER OF THE MIXTURE IN SAID COLUMN TO PRODUCE THE DESIRED BOTTOMS, WITHDRAWING SAID BOTTOMS, HEATING ONE PORTION OF THE WITHDRAWN BOTTOMS IN A SEPARATE REBOILING CIRCUIT AND REBOILING SAID PRIMARY COLUMN WITH THE HOT BOTTOMS, HEATING A SECOND PORTION OF SAID BOTTOMS AND PASSING SAID SECOND PORTION TO A SECONDARY COLUMN, STRIPPING SAID BOTTOMS IN THE LOWER PART OF SAID SECONDARY COLUMN AND WITHDRAWING STRIPPED BOTTOMS AS PRODUCT FROM SAID SECONDARY COLUMN, SUBSTANTIALLY REDUCING THE VAPOR LOAD AT THE TOP OF SAID SECONDARY COLUMN BY REFLUXING SAID SECONDARY COLUMN AT THE TOP THEREOF WITH A REFLUX CIRCUIT COMPRISING WITHDRAWING A CONDENSED SIDE CUT FROM THE UPPER PART OF SAID COLUMN, PASSING A PORTION OF THE WITHDRAWN SIDE CUT TO A SEPARATE STRIPPING OPERATION, COOLING THE REMAINING PORTION OF THE WITHDRAWN SIDE CUT AND REINTRODUCING SAID COOLED PORTION INTO SAID TOWER ABOVE THE POINT OF WITHDRAWAL SO AS TO CONTROL THE AMOUNT OF OVERHEAD IN SAID COLUMN WITHDRAWING AN OVERHEAD FROM SAID SECONDARY COLUMN WHICH INCLUDES ALL OF THE MATERIAL BOILING WITHIN THE RANGE OF THE OVERHEAD OF SAID PRIMARY COLUMN, CONDENSING SAID OVERHEAD, WITHDRAWING A PORTION OF SAID CONDENSED OVERHEAD AS PRODUCT AND RETURNING THE REMAINING PORTION OF CONDENSED OVERHEAD COMPRISING NOT MORE THAN 2% BY WEIGHT OF THE INITIAL FEED TO THE PRIMARY COLUMN.

Claim 2

THE METHOD OF SEPARATING A HYDROCARBON MIXTURE BY FRACTIONAL DISTILLATION WHICH COMPRISES, HEATING THE MIXTURE AND PASSING IT TO A PRIMARY FRACTIONATION COLUMN TO OBTAIN A LIGHT DISTILLATE AND A BOTTOMS UNDER CONDITIONS WHICH INCOMPLETELY REMOVE FROM THE BOTTOMS, MATERIALS BOILING WITHIN THE RANGE OF THE LIGHT DISTILLATE, WITHDRAWING THE LIGHT DISTILLATE AS AN OVERHEAD FROM SAID COLUMN, WITHDRAWING AN INTERMEDIATE SIDE STREAM OF CONTROLLED END POINT FROM SAID COLUMN, STRIPPING THE REMAINDER OF THE MIXTURE IN SAID COLUMN TO PRODUCE THE DESIRED BOTTOMS, WITHDRAWING SAID BOTTOMS, HEATING ONE PORTION OF THE WITHDRAWN BOTTOMS IN A SEPARATE REBOILING CIRCUIT AND REBOILING SAID PRIMARY COLUMN WITH THE HOT BOTTOMS, HEATING A SECOND PORTION OF SAID BOTTOMS AND PASSING SAID SECOND PORTION TO A SECONDARY COLUMN, STRIPPING SAID BOTTOMS IN THE LOWER PART OF SAID SECONDARY COLUMN AND WITHDRAWING STRIPPED BOTTOMS AS PRODUCT FROM SAID SECONDARY COLUMN, SUBSTANTIALLY REDUCING THE VAPOR LOAD AT THE TOP OF SAID SECONDARY COLUMN BY REFLUXING SAID SECONDARY COLUMN AT THE TOP THEREOF WITH A REFLUX CIRCUIT COMPRISING WITHDRAWING A CONDENSED SIDE CUT FROM THE UPPER PART OF SAID COLUMN, PASSING A PORTION OF THE WITHDRAWN SIDE CUT TO A SEPARATE STRIPPING OPERATION, COOLING THE REMAINING PORTION OF THE WITHDRAWN SIDE CUT AND REINTRODUCING SAID COOLED PORTION INTO SAID TOWER ABOVE THE POINT OF WITHDRAWAL SO AS TO CONTROL THE AMOUNT OF OVERHEAD IN SAID COLUMN WITHDRAWING AN OVERHEAD FROM SAID SECONDARY COLUMN WHICH INCLUDES ALL OF THE MATERIAL BOILING WITHIN THE RANGE OF THE OVERHEAD OF SAID PRIMARY COLUMN, CONDENSING SAID OVERHEAD, WITHDRAWING A PORTION OF SAID CONDENSED OVERHEAD AS PRODUCT AND RETURNING THE REMAINING PORTION OF CONDENSED OVERHEAD COMPRISING NOT MORE THAN 2% BY WEIGHT OF THE INITIAL FEED TO THE PRIMARY COLUMN.