Method and apparatus for the control of a continuously operating superatmospheric distillation process

Claim 1

IN A PROCESS FOR THE CONTINUOUS DISTILLATION OF A STREAM OF AN INTAKE MIXTURE AT SUPERAOMSPHERIC PRESSURE IN A MULISTAGE DISTILLATION COLUMN IN WHICH OVERHEAD VAPORS ARE REMOVED AND CONDENSED IN A TOP PRODUCT CONDENSER, COLLECTED IN AN ACCUMULATOR AND BOTH REFLUX IN THE UPPER PORTION AND RE-EVAPORATION IN THE BOTTOM PORTION OF THE COLUMN OCCUR, AND WHEREIN THE AMOUNT OF REFLUX, THE DEGREE OF RE-EVAPORATION, THE TOP PRODUCT FLOW AND THE BOTTOM PRODUCT FLOW ARE CONTROLLED SUCH THAT THE TOP PRODUCT ACCUMULATOR LEVEL AND THE BOTTOM PRODUCT LEVEL ARE ADJUSTED TO PREDETERMINED LEVELS AND THE DERSIRED QUALITY OF THE TOP AND BOTTOM PRODUCTS ATTAINED, THE IMPROVEMENT COMPRISING: CONTROLLING THE FLOW OF COOLING MEDIUM SUPPLIED TO THE CONDENSER, SAID CONTROL BEING IN A DIRECTION TO SUPPLY THE MAXIMUM POSSIBLE QUANTITY OF COOLING MEDIUM TO THE CONDENSE; MEASURING THE PRESSURE IN THE COLUMN; AND ONLY DECREASING SAID SUPPLY OF COOLING MEDIUM WHEN SAID MEASURED PRESSURE SUBSTANTIALLY EQUALS THE MINIMUM PERMISSIBLE PRESSURE IN THE COLUMN.