Gasoline hydrocarbon separation recovery process using zeolitic molecular sieves

Claim 1

AN IMPROVED PROCESS FOR SEPARATING STRAIGHT-CHAIN PARAFFINIC HYDROCARBONS FROM A FEED CONTAINING SAID STRAIGHT-CHAIN HYDROCARBONS IN MIXTURE WITH NON-STRAIGHTCHAIN HYDROCARBONS WHICH COMPRISES PASSING A GASEOUS STREAM OF SAID FEED INTO A MOLECULAR SIEVE ZONE CONTAINING MOLECULAR SIEVES HAVING PORE DIAMETERS OF ABOUT 5 ANGSTROM UNITS, MAINTAINING AN ADSORPTION TEMPERATURE OF ABOUT 175* TO ABOUT 400*F. AND AN ADSORPTION PRESSURE OF FROM ABOUT 5 TO ABOUT 100 P.S.I.G. IN SAID SIEVEZONE, WITHDRAWING UNADSORBED NON-STRAIGHT-CHAIN HYDROCARBONS FROM SAID SIEVE ZONE WHILE ADSORBING STRAIGHTCHAIN HYDROCARBONS ON SAID MOLECULAR SIEVES, ESTABLISHING OPEN COMMUNICATION BETWEEN SAID SIEVE ZONE AND A QUENCHING ZONE MAINTAINED AT A LOWER PRESSURE THAN SAID SIEVE ZONE, DEPRESSURING SAID SIEVE ZONE BY PASSING AT LEAST A PORTIUON OF THE VAPORS IN SAID SIEVE ZONE TO SAID QUENCHING ZONE, MAINTAINING A REDUCED PRESSURE IN SAID QUENCHING ZONE BY QUENCHING SAID VAPORS WITH COLD FEED TO A TEMPERATURE CORRESPONDING TO A PRESSURE SUBSTANTIALLY THE SAME AS A DESIRED DESOPTION PRESSURE UNTIL SAID DESORPTION PRESSURE OBTAINS WITHIN SAID SIEVE ZONE, PASSING A HYDROCARBON GAS INTO SAID SIEVE ZONE, WHEREBY NORMAL PARAFFINS ARE DESORBED AND SAID HYDROCARBON GAS ADSORBED, MAINTAINING A PRESSURE OF FROM ABOUT 5 TO 20 P.S.I.G. IN SAID SIEVE ZONE DURING SAID DESORPTION STEP, SAID DESORPTION PRESSURE BEING LOWER THAN SAID ADSORPTION PRESSURE, WITHDRAWING SAID NORMAL DESORBED HYDROCARBONS, THEREAFTER REPRESSURING THE SAID SIEVE ZONE TO ADSORPTION PRESSURES, AND AGAIN PASSING SAID GASEOUS STREAM INTO SAID SIEVE ZONE.