Regenerative heat exchange in low temperature gas fractionation

Claim 1

IN A PROCESS FOR THE LOW TEMPERATURE FRACTIONAL SEPARATION OF A PREDETERMINED AMOUNT OF A GAS MIXTURE IN A RECTIFICATION COLUMN, WHICH PROCESS COMPRISES THE PRELIMINARY STEPS OF PASSING AN IMPURE GAS MIXTURE FEED THROUGH ONE OF AT LEAST THREE CYCLICALLY INTERCHANGEABLE REGENERATORS, THE GENERATOR IN THE FIRST CYCLE SERVING TO COOL SAID FEED AND CONDENSE THE CONDENSABLE IMPURITIES IN THE IMPURE FEED, THE REGENERATOR IN THE SECOND CYCLE SERVING TO REMOVE THE IMPURITIES BY HAVING A SCAVENGER GAS TRAVERSE THE REGENERATOR TO SUBLIME AND CARRY AWAY SAID IMPURITIES, AND THE REGENERATOR IN THE THIRD CYCLE SERVING TO HEAT THE IMPROVEMENT WHICH COMPRISES PASSING AN FIRST CYCLE, THE IMPROVEMENT WHICH COMPRISES PASSSING AN AMOUNT OF SAID IMPURE FEED THROUGH THE FIRST-CYCLE REGENERATOR IN EXCESS OF THE PREDETERMINED AMOUNT OF GAS MIXTURE FRACTIONATED AND SEPARATED IN THE RECTIFICATION COLUMN, PASSING THE HEATED EXCESS OF SUBSTANTIALLY UNSATURATED GAS MIXTURE EFFLUENT FROM THE THIRD-CYCLE REGENERATOR IN INDIRECT HEAT EXCHANGE WITH PURE GAS FRACTIONS SEPARATED IN THE RECTIFICATION COLUMN, EXPANDING THE EXCESS GAS MIXTURE AND PASSING IT THROUGH THE SECOND-CYCLE REGENERATOR AS SCAVENGER GAS, THEREBY SUBLIMING AND REMOVING THE CONDENSED IMPURITIES OBTAINED IN THE FIRST CYCLE, AND THEN DISCARDING SAID SCAVENGER GAS WITH THE CONDENSED IMPURITIES THEREIN.