GB824635A - Process for improving kerosenes and diesel fuels - Google Patents

Abstract

A process for upgrading petroleum fractions containing aromatic and sulphur compounds and boiling in the range 300 DEG to 650 DEG F. comprises first desulphurizing the fractions to not more than 20 p.p.m. of sulphur and thereafter hydrogenating them over a nickel catalyst at hydrogen rates in excess of 2000 SCF/Bbl. The first stage desulphurization is preferably effected by hydrofining over cobalt molybdate on alumina at 600 DEG to 800 DEG F., 200 to 800 p.s.i.g. and 1 V/hr./V. In the second hydrogenation stage the nickel is preferably supported on kieselguhr, the preferred conditions being 500-550 DEG F., 200-800 p.s.i.g., 1-5 V/hr/V and 2000-10,000 SCF/B. Recycle hydrogen may be used in both stages, H2S being scrubbed out before contact with the Ni catalyst, but preferably retained for the cobalt molybdate hydrofining stage. In an example a 300-650 DEG F. diesel fuel fraction is heated to 725 DEG F. and passed downwardly first over cobalt molybdate and then nickel in countercurrent to H2S free hydrogen which is not scrubbed free from the H2S formed in the Ni stage between stages. The oil is cooled to 500-550 DEG F. by heat exchange with the cold feed between the stages. The process is particularly applicable to the saturation of fractions containing 10-50% of atomatics and having a naphthalene ring content below 30%.ALSO:A process for upgrading petroleum fractions containing aromatic and sulphur compounds and boiling in the range 300 DEG to 650 DEG F., comprises first desulphurizing the fractions to not more than 20 p.p.m. of sulphur and thereafter hydrogenating them over a nickel catalyst at hydrogen rates in excess of 2000 SCF/Bbl. The first stage desulphurization is preferably effected by hydrofining over cobalt molybdate/alumina at 600 DEG to 800 DEG F., 200 to 800 p.s.i.g., and 1 v./H2/v. In the second hydrogenation stage the nickel is preferably supported on kieselguhr, the preferred conditions being 500-550 DEG F., 200-800 p.s.i.g., 1-5 v./H2/v. and 2000-10,000 SCF/B. Recycle hydrogen may be used in both stages, H2S being scrubbed out before contact with the Ni catalyst, but preferably retained for the cobalt molybdate hydrofining stage. In an example a 300-650 DEG F. diesel fuel fraction is heated to 725 DEG F. and passed downwardly first over cobalt molybdate and then nickel in countercurrent to H2S-free hydrogen which is not scrubbed free from the H2S formed in the Ni stage between stages. The oil is cooled to 500-550 DEG F. by heat exchange with the cold feed between the stages. The process is particularly applicable to the saturation of fractions containing 10-50% of aromatics and having a naphthalene ring content below 30%.