Qjivaiiov snoonilnod

Claim 1

AN INTERNAL-REFRIGERANT LOW-TEMPERATURE FRACTIONAL DISTILLATION PROCESS FOR SEPARATING A MULTI-COMPONENT MIXTURE OF VAPORIZABLE MATERIAL INTO A LOW-BOILING FRACTION AND HIGH-BOILING FRACTION WHICH COMPRISES, PASSING SAID MIXTURE INTO FRACTIONATION ZONE, WITHDRAWING A LIQUID STREAM OF KETTLE PRODUCT FROM SAID FRACTIONATION ZONE, PASSING AT LEAST A PORTION OF SAID STREAM THROUGH AN EXPANSION ZONE AND THEREIN VAPORIZATING AT LEAST A PORTION OF AND COOLING SAME, PASSING SAID EXPANDED MATERIAL IN INDIRECT HEAT-EXCHANGE RELATIONSHIP WITH OVERHEAD VAPORS OF SAID FRACTIONATION ZONE TO CONDENSE AT LEAST A PORTION OF SAID OVERHEAD VAPORS, UTILIZATING RESULTING CONDENSED LIQUID AS REFLUXING LIQUID IN SAID FRACTIONATION ZONE, WITHDRAWING A FURTHER PORTION OF SAID OVERHEAD VAPORS AS SAID LOWBOILING FRACTION OF SAID MULTI-COMPONENT MIXTURE, WITHDRAWING A FURTHER PORTION OF KETTLE PRODUCT FROM SAID FRACTIONATION ZONE, PASSING SAID WITHDRAWN LIQUID STREAM THROUGH AN EXPANSION ZONE AND VAPORIZING AT LEAST A PORTION OF AND COOLING THE SAME AND PASSING RESULTING EXPANDED AND COOLED MATERIAL IN INDIRECT HEAT-EXCHANGE RELATIONSHIP WITH SAID MIXTURE PASSED INTO SAID FRACTIONATION ZONE, COMPRESSING AND PARTIALLY COOLING SAID EXPANDED MATERIAL, SUBSEQUENTLY PASSING SAID COMPRESSED MATERIAL INTO DIRECT HEAT-EXCHANGE RELATIONSHIP WITH THE KETTLE PRODUCT OF SAID FRACTIONATION ZONE TO TRANSFER HEAT FROM SAID MATERIAL TO SAID KETTLE PRODUCT, AND WITHDRAWING AT LEAST A PORTION OF SAID KETTLE PRODUCT AS SAID HIGHBOILING FRACTION OF SAID MULTI-COMPONENT MIXTURE.