Method of controlling fractionating column reflux

Claim 1

A METHOD FOR FRACTIONALLY DISLILLING A DISTILLABLE MIXTURE IN A FRACTIONAL DISTILLATION ZONE COMPRISING INTRODUCING SAID MIXTURE INTO SAID DISTILLATION ZONE AT A POINT INTERMEDATE THE ENDS, ADDING REBOILING HEAT TO THE KETTLE SECTION OF SAID ZONE, REMOVING LIQUID FROM SAID KETTLE SECTION AS ONE PRODUCT OF THE PROCESS, REMOVING VAPORS FROM THE TOP OF SAID ZONE, CONDENSING AT LEAST A PORTION OF SAID VAPORS, INTRODUCTING AT LEAST A PROTION OF THE CONDENSATE AS REFLUX INTO THE UPPER PORTION OF SAID ZONE AT A MAXIUMUM RATE SHORT OF FLOODING AS DETERMINED BY A FIRST PRESSURE DIFFERTION ZONE, MEASURING A CHANGE IN THE PRESSURE DIFFERENTIAL ACROSS SAID TRAY, REGULATION THE RATE OF INTRODUCTION OF SAID REFLUX INTO SAID ZONE AT A NEW MAXIMUM RATE OF SHORT OF FLOODING IN RESPONSE TO SAID CHANGE IN PRESSURE DIFFERENTIAL, AND REMOVING THE REMAINING CONDENSATE AS A SECOND PRODUCT OF THE PROCESS.

Claim 2

A METHOD FOR FRACTIONALLY DISLILLING A DISTILLABLE MIXTURE IN A FRACTIONAL DISTILLATION ZONE COMPRISING INTRODUCING SAID MIXTURE INTO SAID DISTILLATION ZONE AT A POINT INTERMEDATE THE ENDS, ADDING REBOILING HEAT TO THE KETTLE SECTION OF SAID ZONE, REMOVING LIQUID FROM SAID KETTLE SECTION AS ONE PRODUCT OF THE PROCESS, REMOVING VAPORS FROM THE TOP OF SAID ZONE, CONDENSING AT LEAST A PORTION OF SAID VAPORS, INTRODUCTING AT LEAST A PROTION OF THE CONDENSATE AS REFLUX INTO THE UPPER PORTION OF SAID ZONE AT A MAXIUMUM RATE SHORT OF FLOODING AS DETERMINED BY A FIRST PRESSURE DIFFERTION ZONE, MEASURING A CHANGE IN THE PRESSURE DIFFERENTIAL ACROSS SAID TRAY, REGULATION THE RATE OF INTRODUCTION OF SAID REFLUX INTO SAID ZONE AT A NEW MAXIMUM RATE OF SHORT OF FLOODING IN RESPONSE TO SAID CHANGE IN PRESSURE DIFFERENTIAL, AND REMOVING THE REMAINING CONDENSATE AS A SECOND PRODUCT OF THE PROCESS.