Jet fuel manufacture

Claim 1

A PROCESS FOR MANUFACTURING THERMALLY STABLE JET FUEL, WHICH PROCESS COMPRISES SEPARATING BY DISTILLATION FROM CATALYTICALLY CRACKED GAS OIL CONTAINING CONDENSED BICYCLIC HYDROCARBONS A PLURALITY OF FRACTIONS EACH BOILING WITHIN A 60*F. BOILING RANGE AND ALSO EACH BOILING WITHIN THE RANGE OF ABOUT 450 TO 570*F., SUBJECTING EACH OF SAID FRACTIONS TO A FIRST HYDROGENATION IN THE PRESENCE OF HYDROGEN AND A SULFUR-RESISTANT HYDROGENATION CATALYST UNDER HYDROGENATION CONDITIONS INCLUDING A TEMPERATURE IN THE RANGE OF ABOUT 675 TO 800*F., A PRESSURE IN THE RANGE OF ABOUT 400 TO 2500 P.S.I.G. AND A LIQUID-HOURLY SPACE VELOCITY IN THE RANGE OF ABOUT 0.1 TO 10, EFFECTIVE TO CONVERT SULFUR-CONTAINING AND NITROGEN-CONTAINING COMPOUNDS IN EACH OF SAID FRACTIONS TO SULFUR- AND NITROGENCONTAINING COMPOUNDS BOILING BELOW SAID FRACTIONS AND EFFECTIVE TO CONVERT A SUBSTANTIAL PROPORTION OF THE CONDENSED BICYCLIC AROMATICS IN EACH OF SAID FRACTIONS TO TETRALINS, SEPARATING FROM THE EFFLUENT FROM EACH OF SAID FIRST HYDROGENATIONS SULFUR- AND INTROGEN-CONTAINING COMPOUNDS BOILING BELOW SAID FRACTIONS AND HYDROGEN, THEREAFTER SUBJECTING THE REMAINDER OF SAID HYDROGENATION EFFLUENTS TO A SECOND HYDROGENATION IN THE PRESENCE OF HYDROGEN AND A SECOND HYDROGENATION CATALYST WHICH IS MORE ACTIVE FOR HYDROGENATION OF HYDROCARBONS THAN SAID SULFURRESISTANT CATALYST UNDER CONDITIONS INCLUDING A TEMPERATURE IN THE RANGE OF ABOUT 575 TO 700*F., A PRESSURE IN THE RANGE OF ABOUT 400 TO 2500 P.S.I.G. AND A LIQUID HOURLY SPACE VELOCITY IN THE RANGE OF ABOUT 0.1 TO 5, EFFECTIVE TO CONVERT CONDENSED BICYCLIC HYDROCARBONS TO DECALINS AND SEPARATING BY DISTILLATION FROM THE EFFLUENT OF EACH OF SAID SECOND HYDROGENATIONS A THERMALLY STABLE JET FUEL COMPRISING DECALINS SUBSTANTIALLY FREE OF AROMATICS AND PARAFFINS, SAID JET FUEL HAVING A HEAT OF COMBUSTION OF AT LEAST ABOUT 18,400 B.T.U. PER POUND, AND ABOUT 131,000 B.T.U. PER GALLON, AND A FREEZING POINT OF NOT GREATER THAN ABOUT -70*F.