Hydrorefining of heavy mineral oils

Claim 1

A PROCESS FOR HYDROREFINING OF A CRUDE MINERAL OIL HAVING AN END-BOILING-POINT IN EXCESS OF ABOUT 700* F. AND CONTAINING COMPONENTS BOILING BELOW ABOUT 500* F., AND WHICH NORMALLY TENDS TO DEPOSIT CARBONACEOUS MATERIALS UPON HOT SURFACES, AND WHEREIN THE HYDROGEN UTILIZED UPON HOT SURFACES, AHD WHEREIN THE HYDROGEN GEN STREAM AND A RECYCLE HYDROGEN STREAM CONTAMINATED WITH LIGHT HYDROCARBONS, WHICH COMPRISES HEATING SAID OIL TO SUBSTANTIALLY THE DESIRED HYDROREFINING TEMPERATURE, SUBJECTING THE HEATED OIL TO PARTIAL VAPORIZATION IN THE ABSENCE OF HYDROGEN AND AT A PRESSURE SUBSTANTIALLY LOWER THAN THE PRESSURES TO BE EMPLOYED IN THE HEREINAFTER-DEFINED LIQUID PHASE AND VAPOR PHASE HYDROREFINING ZONES, SAID PRESSURE AND TEMPERATURE OF VAPORIZATION BEING ADJUSTED TO PRODUCE (1) A VAPOR PHASE COMPRISING SUBSTANTIALLY ALL OF THE OIL COMPONENTS BOILING BELOW ABOUT 250* F. AND THE PREDOMINANT PORTION OF OIL COMPONENTS BOILING BELOW ABOUT 500*F. AND (2) A LIQUID RESIDUAL OIL PHASE, SUBJECTING SAID LIQUID PHASE TO CATALYTIC HYDROREFINING IN A FIRST CATALYTIC CONTACTING ZONE IN ADMIXTURE WITH SUBSTANTIALLY ALL OF SAID MAKEUP HYDROGEN STREAM AND IN THE ABSENCE OF SAID VAPOR PHASE, SUBJECTING SAID VAPOR PHASE TO CATALYTIC HYDROREFINING IN A SECOND CATALYTIC CONTACTING ZONE IN ADMIXTURE WITH AT LEAST A SUBSTANTIAL PORTION OF SAID RECYCLE HYDROGEN STREAM, AND RECOVERING A REBLENDED MIXTURE OF HYDROREFINED OILS FROM SAID CONTACTING ZONES, THE TOTAL HYDROGEN ADMIXED WITH SAID LIQUID PHASE BEING RELATIVELY LESS CONTAMINATED WITH LIGHT HYDROCARBONS THAN THE TOTAL HYDROGEN STREAM ADMIXED WITH SAID VAPOR PHASE.