Process for refining methanol

Claim 1

IN A PROCESS FOR REFINING CRUDE METHANOL TYPICALLY CONTAINING ABOUT 93 TO 98% BY WEIGHT METHANOL, 1 TO 3% HIGH BOILERS, SOME WHICH ARE CAPABLE OF DEGRADING TO LOW BOILING IMPURITIES UNDER DISTILLATION CONDITIONS, AND 1 TO 4% LOW BOILERS, THE STEPS OF INTRODUCING CRUDE METHANOL INTO THE BOTTOM HALF PORTION OF A FIRST DISTILLATION COLUMN, DISTILLING SAID CRUDE METHANOL BY WITHDRAWING A BOTTOM STREAM CONTAINING SUBSTANTIALLY ALL OF THE HIGH BOILERS WHILE WITHDRAWING AN OVERHEAD STREAM CONTAINING LOW BOILERS, METHANOL, AND SUBSTANTIALLY FREE OF HIGH BOILERS, INTRODUCING SAID OVERHEAD STREAM INTO THE UPPER HALF PORTION OF A SECOND DISTILLATION COLUMN, AND REMOVING OVERHEAD IN SAID SECOND COLUMN THE LOW BOILERS WHILE WITHDRAWING FROM THE BOTTOM OF THIS SECOND COLUMN A LIQUID STREAM OF REFINED METHANOL SUBSTANTIALLY FREE FROM OXIDIZABLE IMPURITIES AND LOW BOILERS.