Separation process

Claim 1

A PROCESS FOR SEPARATING A FEED GAS MIXTURE CONTAINING MOLECULES CAPABLE OF BEING INTERNALLY ADSORBED WITHIN A BED OF ZEOLITIC MOLECULAR SIEVE FROM OTHER MOLECULES WHEREIN A PORTION OF SAID OTHER MOLECULES ARE NON-INTERNALLY SORBED WITHIN SAID BED WHICH COMPRISES THE STEPS OF CONTACTING SAID FEED GAS MIXTURE AT A FIRST HIGHER PRESSURE WITH ONE END OF SAID BED THEREBY ADSORBING THE INTERNALLY ADSORBABLE MOLECULES AND WITHDRAWING A GAS STREAM SUBSTANTIALLY DEPLETED OF SAID INTERNALLY ADSORBABLE MOLECULES AT SAID FIRST HIGHER PRESSURE; CONTINUING SAID CONTACT UNTIL THE LEADING ADSORPTION FRONT REACHES A PREDETERMINED LOCATION AT LEAST PARTIALLY WITHIN THE BED; COCURRENTLY PASSING A PURGE GAS STREAM OF AN EASILY REMOVABLE GAS AT A PRESSURE AT LEAST EQUAL TO THE SUM OF THE PARTIAL PRESSURES OF SAID INTERNALLY ADSORBABLE MOLECULES IN SAID FEED GAS MIXTURE AND ABOUT ADSORPTION TEMPERATURE THROUGH SAID BED UNTIL THE PURGE GAS IN THE EFFLUENT STREAM FROM THE OTHER END OF SAID BED CONSTITUTES AT LEAST 5 VOLUME PERCENT OF SAID EFFLUENT BUT LESS THAN 8 BED VOLUMES AFTER SAID PURGE GAS HAS REACHED EQUILIBRIUM; DEPRESSURIZING SAID BED TO A SECOND LAYER PRESSURE SO AS TO REMOVE ONLY A PORTION OF SAID EASILY REMOVABLE GAS AND SAID OTHER MOLECULES FROM SAID BED; AND FURTHER DEPRESSURIZING SAID BED TO A THIRD LOWEST PRESSURE THEREBY REMOVING SAID INTERNALLY ADSORBABLE MOLECULES FROM SAID BED.