Fractionation control system for controlling and optimizing fractionation tower material balance and heat input

Claim 1

IN A FRACTIONATION SYSTEM WHEREIN MEANS ARE PROVIDED FOR DIRECTING A FEED MIXTURE CONTAINING AT LEAST TWO COMPONENTS TO A FRACTIONATION COLUMN, WHEREIN MEANS ARE PROVIDED FOR WITHDRAWING AN OVERHEAD PRODUCT FROM AN UPPER PORTION OF SAID ZONE AND FOR RETURNING A PORTION OF SAID OVERHEAD PRODUCT TO THE ZONE AS EXTERNAL REFLUX, WITH MEANS THEREAFTER FOR WITHDRAWING A BOTTOM PRODUCT FROM A LOWER PORTION OF SAID ZONE, AND MEANS FOR INTRODUCING HEAT INTO SAID LOWER PORTION OF SAID ZONE, IN COMBINATION THEREWITH A CONTROL SYSTEM COMPRISING MEANS TO MEASURE THE FEED FLOW RATE TO THE SAID FRACTIONATION COLUMN AND TO ESTABLISH A FIRST SIGNAL REPRESENTATIVE OF THE MEASURED FLOW RATE, MEANS TO MEASURE THE MOL PERCENT OF LIGHT KEY AND LIGHTER COMPONENTS IN SAID FEED AND TO ESTABLISH A SECOND SIGNAL REPRESENTATIVE OF THE MEASURED MOL PERCENTAGE, MEANS RESPONSIVE TO SAID FIRST AND SECOND SIGNALS TO ESTABLISH A THIRD SIGNAL REPRESENTATIVE OF THE RATE OF WITHDRAWAL OF OVERHEAD PRODUCT FROM SAID FRACTIONATION COLUMN, MEANS RESPONSIVE TO SAID THIRD SIGNAL TO ADJUST THE RATE OF WITHDRAWAL OF OVERHEAD PRODUCT FROM SAID FRACTIONATION COLUMN, MEANS RESPONSIVE TO SAID FIRST SIGNAL TO ESTABLISH A FOURTH SIGNAL REPRESENTATIVE OF RATE OF INTRODUCTION OF HEAT TO SAID FRACTIONATION COLUMN, MEANS RESPONSIVE TO SAID FOURTH SIGNAL TO ADJUST THE RATE OF INTRO-