Production of naphthalene

Claim 1

A TWO-STAGE PROCESS FOR MAKING NAPHTHALENE FROM A SULFUR-CONTAINING PETROLEUM FRACTION BOILING MAINLY WITHIN THE RANGE OF 400*F. TO 550*F. AND COMPOSED OF AT LEAST 50% AROMATIC HYDROCARBONS COMPRISING MAINLY ALKYLNAPHTHALENES AND THE REMAINDER COMPRISIANG MAINLY NON-AROMATIC HYDROCARBONS WHICH COMPRISES SUBJECTING SAID PETROLEUM FRACTION TO CONDITIONING TREATMENT IN THE PRESENCE OF DESULFURIZATION CATALYST AND ADDED HYDROGEN UNDER REACTIN CONDITIONS INCLUDING A TEMPERATURE BETWEEN 800* AND 980*F. AND A PRESSURE BETWEEN 150 AND 1000 P.S.I.G.; REGULATING THE TEMPERATURE, PRESSURE, AND AMOUNT OF HYDROGEN ADDED IN SAID CONDITINING STEP TO EFFECT HYDROGEN CONSUMPTION OF FROM 65 TO 500 STANDARD CUBIC FEET PER PERCENT SULFUR IN SAID PETROLEUM FRACTION PER BARREL OF SAID PETROLEUM FRACTION TO CONVERT NONAROMATIC HYDROCARBONS TO LOWER BOILING COMPOUNDS, TO CONVERT SULFUR MAINLY TO HYDROGEN SULFIDE, AND TO AT LEAST PARTIALLY HYDROGENATE A MINOR PROPORTION OF THE AROMATIC HYDROCARBONS WITHOUT SUBSTANTIAL CONVERSION OF THE ALKYLNAPHTHALENES TO NAPHTHALENE; SUBJECTING CONDITIONED REACTION PRODUCT BOILING MAINLY WITHIN THE RANGE OF 400*F. TO 550*F. TO THERMAL TREATMENT IN THE PRESENCE OF ADDED HYDROGEN AT A PRESSURE BETWEEN 150 AND 1000 P.S.I.G., A HYDROGEN TO HYDROCARBON MOLE RATIO OF FROM 3:1 TO 25:1, A RESIDENCE TIME OF FROM 2 TO 300 SECONDS, AND A TEMPERATURE ABOVE 1000*F. SUFFICIENT TO EFFECT DEALKYLATION OF ALKYLNAPHTHALENES AND DEHYDROGENATION OF SAID HYDROGENATED AROMATIC HYDROCARBONS; AND FRACTIONATING THE FINAL REACTION PRODUCT TO RECOVER NAPHTHALENE IN HIGH CONCENTRATION.