Upgrading a naphtha by separation into two fractions and separate treatment of each fraction

Claim 1

A PROCESS FOR UPGRADING A NAPHTHA WHICH COMPRISES SEPARATING SAID NAPHTHA INTO A LIGHT FRACTION HAVING A FINAL BOILING POINT BETWEEN 200*F. AND 280*F. AND A HEAVY FRACTION HAVING AN INITIAL BOILING POINT BETWEEN 200*F. AND 280*F., CONTACTING THE HEAVY FRACTION WITH A CATALYST COMPRISING ZINC OXIDE AND ZINC CHROMITE AND CONTAINING BETWEEN ABOUT 10 AND 90% ZINC OXIDE BASED ON THE COMBINED WEIGHTS OF ZINC OXIDE AND ZINC CHROMITE AT A TEMPERATURE BETWEEN ABOUT 900-1050*F., A PRESSURE BETWEEN ABOUT 400 AND 600 P.S.I.G. IN THE PRESENCE OF ADDED HYDROGEN TO EFFECT THE SUBSTANTIAL SATURATION OF OLEFINS PRESENT IN SAID HEAVY FRACTION AND TO EFFECT THE SUBSTANTIAL PRODUCTION OF AROMATIC HYDROCARBONS, DESULFURIZING THE LIGHT NAPHTHA FRACTION, INTRODUCING THE DESULFURIZED LIGHT NAPHTHA FRACTION TO A SEPARATION ZONE WHEREIN STRAIGHT CHAIN HYDROCARBONS ARE SEPARATED FROM NON-STRAIGHT CHAIN HYDROCARBONS, COMBINING THE SEPARATED NON-STRAIGHT CHAIN HYDROCARBONS WITH THE TREATED HEAVY FRACTION, CONTACTING THE STRAIGHT CHAIN HYDROCARBONS IN AN ISOMERIZATION ZONE WITH AN ISOMERIZATION CATALYST AND RETURNING THE PRODUCTS OF SAID ISOMERIZATION ZONE TO SAID SEPARATION ZONE.