Extractive distillation in combination with multi-stage evaporation

Claim 1

PROCESS FOR THE EXTRACTIVE DISTILLATION OF A COMPONENT MIXTURE WHICH COMPRISES INTRODUCING INTO A MAIN DISTILLATION ZONE HAVING A HEAD AND A SUMP A PREHEATED SUBSTANTIALLY VAPOR PHASE STARTING MIXTURE OF SUBSTANTIALLY LESS DIFFICULTLY VOLATILE AND MORE DIFFICULTLY VOLATILE COMPONENTS AT A FIRST POINT INTERMEDIATE SAID HEAD AND SUMP AND A LIQUID PHASE SUBSTANTIALLY HIGH BOILING ADDED COMPONENT AT A SECOND POINT ABOVE SAID FIRST POINT FOR CARRYING OUT SAID EXTRACTIVE DISTILLATION, RECOVERING SUBSTANTIALLY SAID LESS DIFFICULTLY VOLATILE COMHEAD AND SUBSTANTIALLY SAID MORE DIFFICULTLY VOLATILE COMPONENTS AT A THIRD POINT JUST ABOVE SAID SUMP AND SUBSTANTIALLY BELOW SAID FIRST AND SECOND POINTS, REMOVING FROM SAID SUMP LIQUID PHASE SUMP MIXTURE INCLUDING SUBSTANTIALLY SAID ADDED COMPONENT AND ATTENDANT MORE DIFFICULTLY VOLATILE COMPONENTS, PASSING SAID SUMP MIXTURE IN SERIES FLOW THROUGH A PLURALITY OF SERIES EVAPORATION ZONES EACH FOLLOWED BY A CORRESPONDING AUXILIARY DISTILLATION ZONE HAVING AN AUILIARY SUMP, SUCH THAT IN EACH SERIES EVAPORATION ZONE QUANTITIES SUBSTANTIALLY OF MORE DIFFICULTLY VOLATILE COMPONENTS ARE VAPORIZED FROM SAID SUMP MIXTURE AND IN EACH FOLLOWING CORRESPONDING AUXILIARY DISTILLATION ZONE FURTHER QUANTITIES SUBSTANTIALLY OF MORE DIFFICULTLY VOLATILE COMPONENTS ARE VAPORIZED THEREFROM, WITH THE SUMP PRODUCT IN THE LAST AUXILIARY DISTILLATION ZONE BEING COMPOSED ESSENTIALLY OF ADDED COMPONENT, PASSING VAPORIZED QUANTITIES SUBSTANTIALLY OF MORE DIFFICULTLY VOLATILE COMPONENTS FROM EACH SUBSEQUENT SERIES EVAPORATION ZONE AND FOLLOWING CORRESPONDING AUXILIARY ZONE BACK TO THE SUMP OF THE NEXT PRECEDING AUXILIARY ZONE AND PASSING VAPORIZED QUANTITIES SUBSTANTIALLY OF MORE DIFFICULTLY VOLATILE COMPONENTS FROM THE FIRST SERIES EVAPORATION ZONE AND FOLLOWING CORRESPONDING AUXILIARY ZONE BACK TO THE SUMP OF SAID MAIN DISTILLATION ZONE, AND SUPPLYING THE ENTIRE HEAT FOR THE SYSTEM TO THE SUMP OF SAID LAST AUXILIARY ZONE AND RECYCLING THE SO-HEATED ADDED COMPONENT FROM THE SUMP OF SAID LAST AUSILIARY ZONE BACK TO SAID SECOND POINT OF INTRODUCTION INTO THE MAIN DISTILLATION ZONE AFTER PASSAGE IN INDIRECT HEAT EXCHANGE FIRST WITH EACH OF SAID SERIES EVAPORATION ZONES FROM THE LAST TO THE FIRSTS, RESPECTIVELY, AND THEREAFTER WITH THE STRATING MIXTURE PRIOR TO INTRODUCTION OF SUCH STARTING MIXTURE INTO THE MAIN DISTILLATION ZONE, WHEREBY THE SO-HEATED ADDED COMPONENT PROVIDES THE NECESSARY HEAT FOR VAPORIZING THE MORE DIFFICULTLY VOLATILE COMPONENTS BEING PASSED BACK TO THE SUMP OF SAID MAIN DISTILLATION ZONE, FOR PREHEATING THE STARTING MIXTURE INTRODUCED INTO SAID MAIN DISTILLATION ZONE, AND FOR CARRYING OUT THE EXTRACTIVE DISTILLATION IN SAID MAIN DISTILLATION ZONE.