Method for fractionating gaseous mixtures

Claim 1

METHOD OF SEPARATING GASEOUS MIXTURE IN A FRACTIONATING OPERATION, IN WHICH OPERATION COOLED GASEOUS MIXTURE IS SUBJECTED TO FRACTIONATION IN A RELATIVELY HIGH PRESSURE FRACTIONATING ZONE AND A RELATIVELY LOW PRESSURE FRACTIONATING ZONE THEREBY TO PRODUCE COLD COMPONENTS OF THE GASEOUS MIXTURE, COMPRISING THE STEPS OF COOLING COMPRESSED GASEOUS MIXTURE BY HEAT INTERCHANGE WITH AT LEAST ONE COLD COMPONENT OF THE GASEOUS MIXTURE TO EFFECT PARTIAL LIQUEFACTION OF THE GASEOUS MIXTURE, SEPARATING THE PARTIALLY LIQUEFIED GASEOUS MIXTURE INTO A VAPOR PORTION AND A LIQUID PORTION, SAID PORTIONS BEING IN CONTACT WITH EACH OTHER, EXPANDING THE LIQUID PORTION TO A LOWER PRESSURE WITH PRODUCTION OF EXTERNAL WORK, SUPERHEATING THE VAPOR PORTION BY HEAT INTERCHANGE WITH COMPRESSED GASESOUS MIXTURE DURING THE COOLING AND PARTIAL LIQUEFACTION OF THE GASEOUS MIXTURE, EXPANDING THE SUPERHEATED VAPOR PORTION TO A LOWER PRESSURE WITH PRODUCTION OF EXTERNAL WORK, THE EXPANSION OF THE LIQUID PORTION AND THE EXPANSION OF THE VAPOR PORTION BEING CONDUCTED IN SEPARATE ZONES, AND PASSING THE EXPANDED LIQUID PORTION AND AT LEAST A PORTION OF THE EXPANDED VAPOR PORTION, AT EQUAL PRESSURES, TO SID RELATIVELY HIGH PRESSURE FRACTIONATING ZONE.