Process for producing high octane gasoline

Claim 1

A PROCESS FOR UPGRADING A HYDROCARBON STREAM CONSISTING PRINCIPALLY OF A MIXTURE OF C6-C7 HYDROCARBONS INCLUDING A SUBSTANTIAL AMOUNT OF N-HEPTANE WHICH COMPRISES THE STEPS OF: (1) REFORMING SAID MIXTURE TO PRODUCE AN EFFLUENT STREAM CONTAINING PARAFFINS, NAPHTHENES, AND AROMATICS INCLUDING BENZENE; (2) FRACTIONATING THE EFFLUENT STREAM OFSTEP (1) TO RECOVER AN OVERHEAD STREAM OF PRINCIPALLY C7 AND LIGHTER HYDROCARBONS AND A BOTTOMS STREAM OF PRINCIPALLY C8 AND HEAVIER HYDROCARBONS: (3) SOLVENT EXTRACTING THE OVERHEAD STREAM OF STEP (2) TO RECOVER AN AROMATIC EXTRACT STREAM OF PRINCIPALLY BENZENE AND A RAFFINATE STREAM OF PRINCIPALLY PARAFFINIC AND NAPHTHENIC OF C6-C7 HYDROCARBONS: (4) FRACTIONATING THE RAFFINATE STREAM OF STEP (3) TO RECOVER AN OVERHEAD STREAM OF PRINCIPALLY C6 HYDROCARBONS AND A BOTTOM STREAM OF PRINCIPALLY C7 HYDROCARBONS INCLUDING SUBSTANTIALLY ALL OF THE N-HEPTANE IN SAID RAFFINATE STREAM; (5) ISOMERIZING THE BOTTOMS STREAM OF STEP (4) AT A TEMPERATURE IN THE RANGE OF 200 TO 350*F. TO PRINCIPALLY A STREAM OF C7 BRANCHED CHAIN ISOMERS; (6) FRACTIONATING THE ISOMERIZATE FROM STEP (5) INTO A LIGHTER STREAM COMPRISING HYDROCARBONS BOILING BELOW ABOUT 190*F. AS A HIGH OCTANE MOTOR FUEL, AN INTERMEDIATE STREAM BOILING IN THE RANGE OF ABOUT 190 TO 200*F., AND A HEAVIER STREAM BOILING ABOVE ABOUT 200*F.; (7) RECYCLING THE HEAVIER STREAM OF STEP (6) TO STEP (1); AND (8) RECYCLING THE INTERMEDIATE STREAM OF STEP (6) TO STEP (5) TO FORM HIGHER OCTANE ISOMERS THEREOF.