Optimum fractionation and steam production

Claim 1

IN THE FRACTIONATION OF A HOT VAPORCONTAINING FEED, THE STEPS COMPRISING FEEDING A HOT VAPOR CONTAINING FEED TO A FRACTIONATION ZONE NEAR ONE END THEREOF, REMOVING LIQUID FROM SAID END OF SAID ZONE, PASSING SAID LIQUID THROUGH A HEAT ETRACTION ZONE TO EXTRACT HEAT FROM SAID LIQUID, RETURNING TO THE FRACTIONATION ZONE AT A POINT THEREOF INTERMEDIATE THE VAPOR CONTAINING FEED POINT AND THE OTHER END OF SAID FRACTIONATION ZONE AS AN INTERMEDIATE REFLUX THEREFOR LIQUID FROMWHICH HEAT HAS BEEN EXTRACTED IN SAID EXTRACTION ZOE, INTRODUCING A REFLUX INTO SAID FRACTIONATION ZONE AT SAID OTHER END OF SAID FRACTIONATION ZONE, SENSING FLOW OF REFLUX PASSING A POINT IN SAID FRACTIONATION ZONE INTERMEDIATE THE POINT AT WHICH SAID INTERMEDIATE REFLUX IS INTRODUCED AND THE INTRODUCTION OF REFLUX TO SAID OTHER END OF SAID FRACTIONATION ZONE, CONTROLLING THE RATE OF FLOW OF SAID FRACTIONATION ZONE, CONTROLLING THE RATE OF FLOW OF SAID LIQUID FROM SAID END OF SAID FRACTIONATION ZONE TO, THROUGH, AND BACK FROM SAID HEAT EXTRACTION ZONE AND ADJUSTING SAID RATE OF FLOW RESPONSIVE TO SAID SENSED FLOW OF REFLUX PASSING SAID POINT IN SAID FRACTIONATION ZONE.