Hydroisomerization process

Claim 1

A COMBINATION HYDROISOMERIZATION AND DEHYDROGENATION PROCESS FOR THE SIMULTANEOUS PRODUCTION OF DIMETHYLBUTANES AND BENZENE, SAID PROCESS SELF-SUFFICIENT IN HYDROGEN REQUIREMENT, WHICH COMPRISES PASSING TO A FIRST FRACTIONATION ZONE AN ISOMERIZABLE HEXANE HYDROCARBON FRACTION IN COMBINATION WITH LIQUID PHASE HYDROISOMERIZATION ZONE EFFLUENT PRODUCED AS HEREINAFTER DESCRIBED, FRACTIONATING SAID HYDROCARBONS TO PRODUCE A SUBSTANTIALLY CYCLOHEXANE-FREE OVERHEAD HYDROCARBON FRACTION AND TO PRODUCE A SUBSTANTIALLY PURE CYCLIS HYDROCARBON BOTTOMS FRACTION COMPRISING CYCLOHEXANE, PASSING SAID CYCLOHEXANE BOTTOMS FRACTION TO A DEHYDROGENATION ZONE HEREINAFTER DESCRIBED, PASSING SAID SUBSTANTIALLY CYCLOHEXANE-FREE OVERHEAD HEXANE FRACTION FROM SAID FIRST FRACTIONATION ZONE TO A SECOND FRACTIONATION ZONE AS FEED THEREFOR, FRACTIONATING SAID HYDROCARBONS TO PRODUCE AN OVERHEAD HYDROCARBON FRACTION CONTAINING 2,2- AND 2,3DIMETHYLBUTANES AND TO PRODUCE A BOTTOMS HYDROCARBON FRACTION CONTAINING METHYLPENTANES, NORMAL HEXANE, AND METHYLCYCLOPENTANE, REMOVING SAID OVERHEAD HYDROCARBON FRACTION CONTAINING 2,2- AND 2,3-DIMETHYLBUTANES AS ONE PRODUCT FROM THE PROCESS, PASSING SAID LAST MENTIONED BOTTOMS HYDROCARBON FRACTION CONTAINING METHYLPENTANES, NORMAL HEXANE, AND METHYLCYCLOPENTANE ALONG WITH HYDROGEN AT LEAST SOME OF WHICH IS PRODUCED BY DEHYDROGENATION AS HEREINAFTER DESCRIBED TO A HYDROISOMERIZATION ZONE MAINTAINED AT A TEMPERATURE OF FROM ABOUT 300* F. TO ABOUT 500*F. AND AT A PRESSURE OF FROM ABOUT 300*F. ABOUT 1000 POUNDS PER SQUARE INCH WHEREIN METHYLPENTANES, NORMAL HEXANE, AND METHYLCYCLOPENTANE ARE ISOMERIZED AT A LIQUID HOURLY SPACE VELOCITY OF FROM ABOUT 0.1 TO ABOUT 10 IN THE PRESENCE OF A HYDROISOMERIZATION CATALYST COMPRISING A HYDROGENATION COMPONENT DEPOSITED ON AN ACID-ACTING SUPPORT TO AN EQUILIBRIUM MIXTURE OF HEXANE HYDROCARBONS INCLUDING 2,2- AND 2,3-DIMETHYLBUTANES, METHYLPENTANCES, NORMAL HEXANE, METHYLCYCLOPENTANE, AND CYCLOHEXANE, RECYCLING THE HYDROISOMERIZATION ZONE EFFLUENT TO THE FIRST MENTIONED FRACTIONATION ZONE AS AFORESAID TO RECOVER CYCLOHEXANE THEREFROM AND TO ALLOW RECOVERY THEREFROM OF 2,2- AND 2,3-DIMETHYLBUTANES PRODUCED IN THE PROCESS IN SAID SECOND FRACTIONATION ZONE AS AFORESAID AND TO SEPARATE METHYLPENTANES, NORMAL HEXANE, AND METHYLCYCLOPENTANE AS AFORESAID FOR REUSE AND INTERNAL RECYCLE IN SAID PROCESS, DEHYDROGENATING SAID CYCLOHEXABE FROM THE BOTTOM OF SAID FIRST FRACTIONATION ZONE IN A DEHYDROGENATION ZONE IN THE PRESENCE OF A DEHYDROGENATION CATALYST AT DEHYDROGENATION CONDITIONS TO PRODUCE HYDROGEN AND BENZENE, REMOVING SAID BENZENE AS THE SECOND PRODUCT FROM THE PROCESS, AND RECYCLING AT LEAST A PORTION OF SAID HYDROGEN TO THE HYDROISOMERIZATION ZONE AS THE SOLE SOURCE OF MAKEUP HYDROGEN THEREFOR.