Catalytic desulfurization of petroleum hydrocarbons

Claim 1

A PROCESS FOR THE RECOVERY OF SULPHUR-FREE PRODUCTS FROM NAPHTHENE-CONTAINING CRUDE PETROLEUM BY THE HYDROCATALYTIC DESULPHURISATION PROCESS WITHOUT THE NEED FOR AN EXTRANEOUS SOURCE OF HYDROGEN, WHICH COMPRISES FRACTIONATING THE CRUDE PETROLEUM FOR THE RECOVERY OF A SELECTED NAPHTHENE-CONTAINING LOW-BOILING FRACTION AND A RESIDUE, PASSING SAID LOW-BOILING FRACTION IN ADMIXTURE WITH HYDROGEN DERIVED SOLELY FROM SAID FRACTION TO A FIRST DESULPHURISATION ZONE WHEREIN IT IS CONTACTED WITH A SULPHUR-RESISTANT DEHYDROGENATION-HYDROGENATION CATALYST WHICH IS IMMUNE TO SULPHUR POISONING AND COMBINES ACTIVITY FOR THE DEHYDROGENATION OF NAPHTHENES TO AROMATICS WITH ACTIVITY FOR THE HYDROGENATION OF ORGANICALLY COMBINED SULPHUR IN SAID FRACTION TO HYDROGEN SULPHIDE AT A SELECTED TEMPERATURE WITHIN THE RANGE 750-800* F. AND A SELECTED PRESSURE WITHIN THE RANGE 50-250 P. S. I. GA., SAID TEMPERATURE AND PRESSURE BEING CORRELATED SO THAT ORGANICALLY COMBINED SULPHUR IN SAID FRACTION IS CONVERTED INTO HYDROGEN SULPHIDE AND HYDROGEN IS PRODUCED BY DEHYDROGENATION OF NAPHTHENES CONTAINED IN SAID LOW-BOILING FRACTION IN AN AMOUNT IN EXCESS OF THAT REQUIRED TO CONVERT ORGANICALLY COMBINED SULPHUR CONTAINED IN SAID LOW-BOILING FRACTION INTO HYDROGEN SULPHIDE AND MAINTAIN THE NECESSARY PARTIAL PRESSURE OF HYDROGEN IN SAID ZONE, SEPARATING HYDROGEN SULPHIDE AND A HYDROGEN-RICH GAS MIXTURE FROM THE PRODUCTS OF SAID FIRST DESULPHURISATION ZONE, RECYCLING A PORTION OF SAID HYDROGEN-RICH GAS MIXTURE TO SAID FIRST DESULPHURISATION ZONE TO CONSTITUTE THE WHOLE OF THE HYDROGEN SUPPLIED TO SAID ZONE, THE HYDROGEN RECYCLE RATE BEING SUFFICIENT TO MAINTAIN THE NECESSARY PARTIAL PRESSURE OF HYDROGEN IN SAID ZONE THEREIN, PASSING ANOTHER PORTION OF SAID HYDROGEN-RICH GAS MIXTURE IN ADMIXTURE WITH SAID RESIDUE TO A SECOND DESULPHURISATION ZONE WHEREIN SAID RESIDUE IS CONTACTED WITH A SULPHUR-RESISTANT HYDROGENATION CATALYST AND HYDROGEN OF THE MIXTURE AT A TEMPERATURE AND PRESSURE SUITABLE FOR HYDROFINING OF SAID RESIDUE WHEREBY ORGANICALLY COMBINED SULPHUR CONTAINED IN SAID RESIDUE IS CONVERTED INTO HYDROGEN SULPHIDE, SAID HYDROGEN-RICH GAS MIXTURE CONSTITUTING THE SOLE SOURCE OF HYDROGEN SUPPLIED TO SAHD HYDROFINING STAGE, SEPARATING HYDROGEN SULPHIDE FROM THE PRODUCTS OF SAID SECOND DESULPHURISATION ZONE, AND RECOVERING A SUBSTANTIALLY SULPHUR-FREE PRODUCTS FROM BOTH SAID DESULPHURISATION ZONES.