Low temperature process

Claim 1

METHOD OF REFRIGERATING GASEOUS MATERIAL UNDER SUPERATMOSPHERIC PRESSURE IN A FRACTIONATING OPERATION, IN WHICH OPERATION COMPRESSED GASEOUS FEED MIXTURE IS COOLED AND SEPARATED IN A FRACTIONATING ZONE PRODUCING COLD FRACTIONS OF THE GASEOUS MIXTURE AT LEAST ONE OF WHICH IS PASSED IN HEAT EXCHANGE RELATION WITH THE FEED MIXTURE TO COOL THE FEED MIXTURE AND IN WHICH MAKE-UP REFRIGERATION IS PROVIDED FOR THE FRACTIONATING OPERATION, COMPRISING THE STEPS OF ESTABLISHING HEAT INTERCHANGE BETWEEN GASEOUS MATERIAL UNDER SUPERATMOSPHERIC PRESSURE AND AT LEAST ONE RELATIVELY COLD FLUID OF THE FRACTIONATING OPERATION TO TRANSFER A QUANTITY OF REFRIGERATION TO THE GASEOUS MATERIAL UNDER SUPRATMOSPHERIC PRESSURE. THE QUANTITY OF REFRIGERATION TRANSFERRED TO THE GASEOUS MATERIAL UNDER SUPERATMOSPHERIC PRESSURE PROVIDING A TOTAL REFRIGERATION CONTANT OF THE GASEOUS MATERIAL SUFFICIENT TO EFFECT LIQUEFACTION OF THE GASEOUS MATERAIAL WHEN UNDER A PRESSURE NO GREATER THAN THE CRITICAL PRESSURE OF THE GASEOUS MATERIAL. WITHDRAWING THE GASEOUS MATERIAL CONTAINING TRANSFERRED REFRIGERATION FROM THE FRACTIONATING OPERATION AFTER THE HEAT INTERCHANGE. AND EXPANDING A HIGH PRESSURE FLUID OF THE FRACTIONATING OPERATION WHILE DOING WORK TO PROVIDE REFRIGERATION IN EXCESS OF THE MAKE-UP REFRIGERATION FOR THE FRACTIONATING OPERATION, THE REFRIGATION IN EXCESS OF THE MAKE-UP REFRIGERATION COMPENSATING FOR THE QUANTITY OF REFRIGERATION TRANSFERRED TO THE GASEOUS MATERIAL WITHDRAWN FROM THE FRACTIONATING OPERATION.