Pressure cycle for molecular sieve separation of normal paraffins from hydrocarbon mixtures

Claim 1

A PROCESS FOR SEPARATING NORMAL PARAFFINS CONTAINING AT LEAST FOUR CARBON ATOMS FROM A VAPOR FEED MIXTURE THEREOF WITH AT LEAST OTHER HYDROCARBON WHICH PROCESS COMPRISES: REPEATING IN SEQUENCE THE STEPS OF FLOWING THE HYDROCARBON CONTAINING VAPOR FEED MIXTURE AT A SELECTED INITIAL RELATIVELY HIGH PRESSURE INTO ONE END OF AN ADSORPTION ZONE ALSO HAVING ANOTHER END AND CONTAINING CRYSTALLINE ZEOLITIC MOLECULAR SIEVE MATERIAL WHICH SELECTIVELY ADSORBS SAID NORMAL PARAFFINS HAVING CRITICAL DIMENSIONS UP TO ABOUT 5 ANGSTROM UNITS, AND CONTACTING SAID VAPOR FEED MIXTURES AND SAID MOLECULAR SIEVE MATERIAL AT SAID SELECTED INITIAL RELATIVELY HIGH PRESSURE AND TEMPERATURES BETWEEN ABOUT 660*F. AND 850*F.; DISCHARGING GASEOUS EFFLUENT STREAM FROM THE OTHER END OF SAID ADSORPTION ZONE AT SUBSTANTIALLY THE SELECTED INITIAL RELATIVELY HIGH PRESSURE OF SAID VAPOR FEED MIXTURE TERMINATING THE FLOW OF VAPOR FEED MIXTURE TO SAID ADSORPTION ZONE WHEN SAID MOLECULAR SIEVE IS AT LEAST PARTIALLY LOADED WITH SAID NORMAL PARAFFIN, REDUCING THE