Process for the separation of fluids by extractive distillation

Claim 1

A PROCESS FOR SEPARATING A LIQUID MIXTURE OF COMPONENTS A AND B WHERE THE RELATIVE VOLATILITY OF A TO B IS RESPONSIVE TO CHANGES IN THE CONCENTRATION OF A LIQUID COMBINING AGENT IN CONTACT WITH SAID MIXTURE, SAID COMBINING AGENT BEING CAPABLE OF SELECTIVE COMBINATION WITH AT LEAST ONE OF THE COMPONENTS, COMPRISING THE STEPS OF INTRODUCING SAID LIQUID MIXTURE AND SAID COMBINING AGENT INTO THE TOP OF A FIRST MULTI-STAGE FRACTIONATION ZONE, REGULATING THE CONCENTRATION OF SAID COMBINING AGENT IN SAID FIRST ZONE SO THAT A IS MORE VOLATILE THAN B, FRACTIONATING SAID LIQUID MIXTURE TO PRODUCE A VAPOR ENRICHED IN A AND A FIRST LIQUID PHASE CONTAINING B AND SAID COMBINING AGENT, WITHDRAWING A PORTION OF SAID VAPOR ENRICHED IN A AS A PRODUCT, AND INTRODUCING THE REMAINDER OF SAID VAPOR INTO THE BOTTOM OF A SECOND MULTI-STAGE FRACTIONATING ZONE, INTRODUCING SAID FIRST LIQUID PHASE INTO THE TOP OF SAID SECOND ZONE, CONTACTING DOWNWARDLY FLOWING LIQUID WITH RISING VAPOR TO CONDENSE A VAPOR AND STRIP B FROM SAID FIRST LIQUID PHASE, THEREBY FORMING A VAPOR PHASE ENRICHED IN B AND A SECOND LIQUID PHASE CONTAINING A, B, AND SAID COMBINING AGENT, WHEREIN THE RATIO OF B TO COMBINING AGENT IN SAID SECOND LIQUID PHASE IS LESS THAN IN SAID FIRST LIQUID PHASE, RECYCLING AT LEAST A PORTION OF SAID VAPOR PHASE ENRICHED IN B TO THE BOTTOM OF SAID FIRST ZONE, RECYCLING ALL OF SAID SECOND LIQUID PHASE TO THE TOP OF SAID FIRST ZONE AND PASSING SAID SECOND LIQUID PHASE DOWNWARDLY THROUGH SAID FIRST ZONE COUNTERCURRENT TO RISING VAPOR ENRICHED IN B, WHEREBY A IS STRIPPED FROM SAID SECOND LIQUID PHASE, WITHDRAWING LIQUID MIXTURE OF B AND COMBINING AGENT FROM THE BOTTOM OF SAID FIRST FRACTIONATION ZONE, AND PASSING A PORTION THEREOF TO A SEPARATION ZONE WHEREIN B AND COMBINING AGENT ARE SEPARATED.